1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* Copyright (C) 2008 Oracle. All rights reserved.
4	*/
5
6	#include <linux/sched.h>
7	#include <linux/slab.h>
8	#include <linux/blkdev.h>
9	#include <linux/list_sort.h>
10	#include <linux/iversion.h>
11	#include "misc.h"
12	#include "ctree.h"
13	#include "tree-log.h"
14	#include "disk-io.h"
15	#include "locking.h"
16	#include "backref.h"
17	#include "compression.h"
18	#include "qgroup.h"
19	#include "block-group.h"
20	#include "space-info.h"
21	#include "inode-item.h"
22	#include "fs.h"
23	#include "accessors.h"
24	#include "extent-tree.h"
25	#include "root-tree.h"
26	#include "dir-item.h"
27	#include "file-item.h"
28	#include "file.h"
29	#include "orphan.h"
30	#include "tree-checker.h"
31
32	#define MAX_CONFLICT_INODES 10
33
34	/* magic values for the inode_only field in btrfs_log_inode:
35	*
36	* LOG_INODE_ALL means to log everything
37	* LOG_INODE_EXISTS means to log just enough to recreate the inode
38	* during log replay
39	*/
40	enum {
41	LOG_INODE_ALL,
42	LOG_INODE_EXISTS,
43	};
44
45	/*
46	* directory trouble cases
47	*
48	* 1) on rename or unlink, if the inode being unlinked isn't in the fsync
49	* log, we must force a full commit before doing an fsync of the directory
50	* where the unlink was done.
51	* ---> record transid of last unlink/rename per directory
52	*
53	* mkdir foo/some_dir
54	* normal commit
55	* rename foo/some_dir foo2/some_dir
56	* mkdir foo/some_dir
57	* fsync foo/some_dir/some_file
58	*
59	* The fsync above will unlink the original some_dir without recording
60	* it in its new location (foo2). After a crash, some_dir will be gone
61	* unless the fsync of some_file forces a full commit
62	*
63	* 2) we must log any new names for any file or dir that is in the fsync
64	* log. ---> check inode while renaming/linking.
65	*
66	* 2a) we must log any new names for any file or dir during rename
67	* when the directory they are being removed from was logged.
68	* ---> check inode and old parent dir during rename
69	*
70	* 2a is actually the more important variant. With the extra logging
71	* a crash might unlink the old name without recreating the new one
72	*
73	* 3) after a crash, we must go through any directories with a link count
74	* of zero and redo the rm -rf
75	*
76	* mkdir f1/foo
77	* normal commit
78	* rm -rf f1/foo
79	* fsync(f1)
80	*
81	* The directory f1 was fully removed from the FS, but fsync was never
82	* called on f1, only its parent dir. After a crash the rm -rf must
83	* be replayed. This must be able to recurse down the entire
84	* directory tree. The inode link count fixup code takes care of the
85	* ugly details.
86	*/
87
88	/*
89	* stages for the tree walking. The first
90	* stage (0) is to only pin down the blocks we find
91	* the second stage (1) is to make sure that all the inodes
92	* we find in the log are created in the subvolume.
93	*
94	* The last stage is to deal with directories and links and extents
95	* and all the other fun semantics
96	*/
97	enum {
98	LOG_WALK_PIN_ONLY,
99	LOG_WALK_REPLAY_INODES,
100	LOG_WALK_REPLAY_DIR_INDEX,
101	LOG_WALK_REPLAY_ALL,
102	};
103
104	static int btrfs_log_inode(struct btrfs_trans_handle *trans,
105	struct btrfs_inode *inode,
106	int inode_only,
107	struct btrfs_log_ctx *ctx);
108	static int link_to_fixup_dir(struct btrfs_trans_handle *trans,
109	struct btrfs_root *root,
110	struct btrfs_path *path, u64 objectid);
111	static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
112	struct btrfs_root *root,
113	struct btrfs_root *log,
114	struct btrfs_path *path,
115	u64 dirid, int del_all);
116	static void wait_log_commit(struct btrfs_root *root, int transid);
117
118	/*
119	* tree logging is a special write ahead log used to make sure that
120	* fsyncs and O_SYNCs can happen without doing full tree commits.
121	*
122	* Full tree commits are expensive because they require commonly
123	* modified blocks to be recowed, creating many dirty pages in the
124	* extent tree an 4x-6x higher write load than ext3.
125	*
126	* Instead of doing a tree commit on every fsync, we use the
127	* key ranges and transaction ids to find items for a given file or directory
128	* that have changed in this transaction. Those items are copied into
129	* a special tree (one per subvolume root), that tree is written to disk
130	* and then the fsync is considered complete.
131	*
132	* After a crash, items are copied out of the log-tree back into the
133	* subvolume tree. Any file data extents found are recorded in the extent
134	* allocation tree, and the log-tree freed.
135	*
136	* The log tree is read three times, once to pin down all the extents it is
137	* using in ram and once, once to create all the inodes logged in the tree
138	* and once to do all the other items.
139	*/
140
141	/*
142	* start a sub transaction and setup the log tree
143	* this increments the log tree writer count to make the people
144	* syncing the tree wait for us to finish
145	*/
146	static int start_log_trans(struct btrfs_trans_handle *trans,
147	struct btrfs_root *root,
148	struct btrfs_log_ctx *ctx)
149	{
150	struct btrfs_fs_info *fs_info = root->fs_info;
151	struct btrfs_root *tree_root = fs_info->tree_root;
152	const bool zoned = btrfs_is_zoned(fs_info);
153	int ret = 0;
154	bool created = false;
155
156	/*
157	* First check if the log root tree was already created. If not, create
158	* it before locking the root's log_mutex, just to keep lockdep happy.
159	*/
160	if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &tree_root->state)) {
161	mutex_lock(&tree_root->log_mutex);
162	if (!fs_info->log_root_tree) {
163	ret = btrfs_init_log_root_tree(trans, fs_info);
164	if (!ret) {
165	set_bit(nr: BTRFS_ROOT_HAS_LOG_TREE, addr: &tree_root->state);
166	created = true;
167	}
168	}
169	mutex_unlock(lock: &tree_root->log_mutex);
170	if (ret)
171	return ret;
172	}
173
174	mutex_lock(&root->log_mutex);
175
176	again:
177	if (root->log_root) {
178	int index = (root->log_transid + 1) % 2;
179
180	if (btrfs_need_log_full_commit(trans)) {
181	ret = BTRFS_LOG_FORCE_COMMIT;
182	goto out;
183	}
184
185	if (zoned && atomic_read(v: &root->log_commit[index])) {
186	wait_log_commit(root, transid: root->log_transid - 1);
187	goto again;
188	}
189
190	if (!root->log_start_pid) {
191	clear_bit(nr: BTRFS_ROOT_MULTI_LOG_TASKS, addr: &root->state);
192	root->log_start_pid = current->pid;
193	} else if (root->log_start_pid != current->pid) {
194	set_bit(nr: BTRFS_ROOT_MULTI_LOG_TASKS, addr: &root->state);
195	}
196	} else {
197	/*
198	* This means fs_info->log_root_tree was already created
199	* for some other FS trees. Do the full commit not to mix
200	* nodes from multiple log transactions to do sequential
201	* writing.
202	*/
203	if (zoned && !created) {
204	ret = BTRFS_LOG_FORCE_COMMIT;
205	goto out;
206	}
207
208	ret = btrfs_add_log_tree(trans, root);
209	if (ret)
210	goto out;
211
212	set_bit(nr: BTRFS_ROOT_HAS_LOG_TREE, addr: &root->state);
213	clear_bit(nr: BTRFS_ROOT_MULTI_LOG_TASKS, addr: &root->state);
214	root->log_start_pid = current->pid;
215	}
216
217	atomic_inc(v: &root->log_writers);
218	if (!ctx->logging_new_name) {
219	int index = root->log_transid % 2;
220	list_add_tail(new: &ctx->list, head: &root->log_ctxs[index]);
221	ctx->log_transid = root->log_transid;
222	}
223
224	out:
225	mutex_unlock(lock: &root->log_mutex);
226	return ret;
227	}
228
229	/*
230	* returns 0 if there was a log transaction running and we were able
231	* to join, or returns -ENOENT if there were not transactions
232	* in progress
233	*/
234	static int join_running_log_trans(struct btrfs_root *root)
235	{
236	const bool zoned = btrfs_is_zoned(fs_info: root->fs_info);
237	int ret = -ENOENT;
238
239	if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &root->state))
240	return ret;
241
242	mutex_lock(&root->log_mutex);
243	again:
244	if (root->log_root) {
245	int index = (root->log_transid + 1) % 2;
246
247	ret = 0;
248	if (zoned && atomic_read(v: &root->log_commit[index])) {
249	wait_log_commit(root, transid: root->log_transid - 1);
250	goto again;
251	}
252	atomic_inc(v: &root->log_writers);
253	}
254	mutex_unlock(lock: &root->log_mutex);
255	return ret;
256	}
257
258	/*
259	* This either makes the current running log transaction wait
260	* until you call btrfs_end_log_trans() or it makes any future
261	* log transactions wait until you call btrfs_end_log_trans()
262	*/
263	void btrfs_pin_log_trans(struct btrfs_root *root)
264	{
265	atomic_inc(v: &root->log_writers);
266	}
267
268	/*
269	* indicate we're done making changes to the log tree
270	* and wake up anyone waiting to do a sync
271	*/
272	void btrfs_end_log_trans(struct btrfs_root *root)
273	{
274	if (atomic_dec_and_test(v: &root->log_writers)) {
275	/* atomic_dec_and_test implies a barrier */
276	cond_wake_up_nomb(wq: &root->log_writer_wait);
277	}
278	}
279
280	/*
281	* the walk control struct is used to pass state down the chain when
282	* processing the log tree. The stage field tells us which part
283	* of the log tree processing we are currently doing. The others
284	* are state fields used for that specific part
285	*/
286	struct walk_control {
287	/* should we free the extent on disk when done? This is used
288	* at transaction commit time while freeing a log tree
289	*/
290	int free;
291
292	/* pin only walk, we record which extents on disk belong to the
293	* log trees
294	*/
295	int pin;
296
297	/* what stage of the replay code we're currently in */
298	int stage;
299
300	/*
301	* Ignore any items from the inode currently being processed. Needs
302	* to be set every time we find a BTRFS_INODE_ITEM_KEY and we are in
303	* the LOG_WALK_REPLAY_INODES stage.
304	*/
305	bool ignore_cur_inode;
306
307	/* the root we are currently replaying */
308	struct btrfs_root *replay_dest;
309
310	/* the trans handle for the current replay */
311	struct btrfs_trans_handle *trans;
312
313	/* the function that gets used to process blocks we find in the
314	* tree. Note the extent_buffer might not be up to date when it is
315	* passed in, and it must be checked or read if you need the data
316	* inside it
317	*/
318	int (*process_func)(struct btrfs_root *log, struct extent_buffer *eb,
319	struct walk_control *wc, u64 gen, int level);
320	};
321
322	/*
323	* process_func used to pin down extents, write them or wait on them
324	*/
325	static int process_one_buffer(struct btrfs_root *log,
326	struct extent_buffer *eb,
327	struct walk_control *wc, u64 gen, int level)
328	{
329	struct btrfs_fs_info *fs_info = log->fs_info;
330	int ret = 0;
331
332	/*
333	* If this fs is mixed then we need to be able to process the leaves to
334	* pin down any logged extents, so we have to read the block.
335	*/
336	if (btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
337	struct btrfs_tree_parent_check check = {
338	.level = level,
339	.transid = gen
340	};
341
342	ret = btrfs_read_extent_buffer(buf: eb, check: &check);
343	if (ret)
344	return ret;
345	}
346
347	if (wc->pin) {
348	ret = btrfs_pin_extent_for_log_replay(trans: wc->trans, eb);
349	if (ret)
350	return ret;
351
352	if (btrfs_buffer_uptodate(buf: eb, parent_transid: gen, atomic: 0) &&
353	btrfs_header_level(eb) == 0)
354	ret = btrfs_exclude_logged_extents(eb);
355	}
356	return ret;
357	}
358
359	/*
360	* Item overwrite used by replay and tree logging. eb, slot and key all refer
361	* to the src data we are copying out.
362	*
363	* root is the tree we are copying into, and path is a scratch
364	* path for use in this function (it should be released on entry and
365	* will be released on exit).
366	*
367	* If the key is already in the destination tree the existing item is
368	* overwritten. If the existing item isn't big enough, it is extended.
369	* If it is too large, it is truncated.
370	*
371	* If the key isn't in the destination yet, a new item is inserted.
372	*/
373	static int overwrite_item(struct btrfs_trans_handle *trans,
374	struct btrfs_root *root,
375	struct btrfs_path *path,
376	struct extent_buffer *eb, int slot,
377	struct btrfs_key *key)
378	{
379	int ret;
380	u32 item_size;
381	u64 saved_i_size = 0;
382	int save_old_i_size = 0;
383	unsigned long src_ptr;
384	unsigned long dst_ptr;
385	bool inode_item = key->type == BTRFS_INODE_ITEM_KEY;
386
387	/*
388	* This is only used during log replay, so the root is always from a
389	* fs/subvolume tree. In case we ever need to support a log root, then
390	* we'll have to clone the leaf in the path, release the path and use
391	* the leaf before writing into the log tree. See the comments at
392	* copy_items() for more details.
393	*/
394	ASSERT(root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID);
395
396	item_size = btrfs_item_size(eb, slot);
397	src_ptr = btrfs_item_ptr_offset(eb, slot);
398
399	/* Look for the key in the destination tree. */
400	ret = btrfs_search_slot(NULL, root, key, p: path, ins_len: 0, cow: 0);
401	if (ret < 0)
402	return ret;
403
404	if (ret == 0) {
405	char *src_copy;
406	char *dst_copy;
407	u32 dst_size = btrfs_item_size(eb: path->nodes[0],
408	slot: path->slots[0]);
409	if (dst_size != item_size)
410	goto insert;
411
412	if (item_size == 0) {
413	btrfs_release_path(p: path);
414	return 0;
415	}
416	dst_copy = kmalloc(size: item_size, GFP_NOFS);
417	src_copy = kmalloc(size: item_size, GFP_NOFS);
418	if (!dst_copy || !src_copy) {
419	btrfs_release_path(p: path);
420	kfree(objp: dst_copy);
421	kfree(objp: src_copy);
422	return -ENOMEM;
423	}
424
425	read_extent_buffer(eb, dst: src_copy, start: src_ptr, len: item_size);
426
427	dst_ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
428	read_extent_buffer(eb: path->nodes[0], dst: dst_copy, start: dst_ptr,
429	len: item_size);
430	ret = memcmp(p: dst_copy, q: src_copy, size: item_size);
431
432	kfree(objp: dst_copy);
433	kfree(objp: src_copy);
434	/*
435	* they have the same contents, just return, this saves
436	* us from cowing blocks in the destination tree and doing
437	* extra writes that may not have been done by a previous
438	* sync
439	*/
440	if (ret == 0) {
441	btrfs_release_path(p: path);
442	return 0;
443	}
444
445	/*
446	* We need to load the old nbytes into the inode so when we
447	* replay the extents we've logged we get the right nbytes.
448	*/
449	if (inode_item) {
450	struct btrfs_inode_item *item;
451	u64 nbytes;
452	u32 mode;
453
454	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
455	struct btrfs_inode_item);
456	nbytes = btrfs_inode_nbytes(eb: path->nodes[0], s: item);
457	item = btrfs_item_ptr(eb, slot,
458	struct btrfs_inode_item);
459	btrfs_set_inode_nbytes(eb, s: item, val: nbytes);
460
461	/*
462	* If this is a directory we need to reset the i_size to
463	* 0 so that we can set it up properly when replaying
464	* the rest of the items in this log.
465	*/
466	mode = btrfs_inode_mode(eb, s: item);
467	if (S_ISDIR(mode))
468	btrfs_set_inode_size(eb, s: item, val: 0);
469	}
470	} else if (inode_item) {
471	struct btrfs_inode_item *item;
472	u32 mode;
473
474	/*
475	* New inode, set nbytes to 0 so that the nbytes comes out
476	* properly when we replay the extents.
477	*/
478	item = btrfs_item_ptr(eb, slot, struct btrfs_inode_item);
479	btrfs_set_inode_nbytes(eb, s: item, val: 0);
480
481	/*
482	* If this is a directory we need to reset the i_size to 0 so
483	* that we can set it up properly when replaying the rest of
484	* the items in this log.
485	*/
486	mode = btrfs_inode_mode(eb, s: item);
487	if (S_ISDIR(mode))
488	btrfs_set_inode_size(eb, s: item, val: 0);
489	}
490	insert:
491	btrfs_release_path(p: path);
492	/* try to insert the key into the destination tree */
493	path->skip_release_on_error = 1;
494	ret = btrfs_insert_empty_item(trans, root, path,
495	key, data_size: item_size);
496	path->skip_release_on_error = 0;
497
498	/* make sure any existing item is the correct size */
499	if (ret == -EEXIST || ret == -EOVERFLOW) {
500	u32 found_size;
501	found_size = btrfs_item_size(eb: path->nodes[0],
502	slot: path->slots[0]);
503	if (found_size > item_size)
504	btrfs_truncate_item(trans, path, new_size: item_size, from_end: 1);
505	else if (found_size < item_size)
506	btrfs_extend_item(trans, path, data_size: item_size - found_size);
507	} else if (ret) {
508	return ret;
509	}
510	dst_ptr = btrfs_item_ptr_offset(path->nodes[0],
511	path->slots[0]);
512
513	/* don't overwrite an existing inode if the generation number
514	* was logged as zero. This is done when the tree logging code
515	* is just logging an inode to make sure it exists after recovery.
516	*
517	* Also, don't overwrite i_size on directories during replay.
518	* log replay inserts and removes directory items based on the
519	* state of the tree found in the subvolume, and i_size is modified
520	* as it goes
521	*/
522	if (key->type == BTRFS_INODE_ITEM_KEY && ret == -EEXIST) {
523	struct btrfs_inode_item *src_item;
524	struct btrfs_inode_item *dst_item;
525
526	src_item = (struct btrfs_inode_item *)src_ptr;
527	dst_item = (struct btrfs_inode_item *)dst_ptr;
528
529	if (btrfs_inode_generation(eb, s: src_item) == 0) {
530	struct extent_buffer *dst_eb = path->nodes[0];
531	const u64 ino_size = btrfs_inode_size(eb, s: src_item);
532
533	/*
534	* For regular files an ino_size == 0 is used only when
535	* logging that an inode exists, as part of a directory
536	* fsync, and the inode wasn't fsynced before. In this
537	* case don't set the size of the inode in the fs/subvol
538	* tree, otherwise we would be throwing valid data away.
539	*/
540	if (S_ISREG(btrfs_inode_mode(eb, src_item)) &&
541	S_ISREG(btrfs_inode_mode(dst_eb, dst_item)) &&
542	ino_size != 0)
543	btrfs_set_inode_size(eb: dst_eb, s: dst_item, val: ino_size);
544	goto no_copy;
545	}
546
547	if (S_ISDIR(btrfs_inode_mode(eb, src_item)) &&
548	S_ISDIR(btrfs_inode_mode(path->nodes[0], dst_item))) {
549	save_old_i_size = 1;
550	saved_i_size = btrfs_inode_size(eb: path->nodes[0],
551	s: dst_item);
552	}
553	}
554
555	copy_extent_buffer(dst: path->nodes[0], src: eb, dst_offset: dst_ptr,
556	src_offset: src_ptr, len: item_size);
557
558	if (save_old_i_size) {
559	struct btrfs_inode_item *dst_item;
560	dst_item = (struct btrfs_inode_item *)dst_ptr;
561	btrfs_set_inode_size(eb: path->nodes[0], s: dst_item, val: saved_i_size);
562	}
563
564	/* make sure the generation is filled in */
565	if (key->type == BTRFS_INODE_ITEM_KEY) {
566	struct btrfs_inode_item *dst_item;
567	dst_item = (struct btrfs_inode_item *)dst_ptr;
568	if (btrfs_inode_generation(eb: path->nodes[0], s: dst_item) == 0) {
569	btrfs_set_inode_generation(eb: path->nodes[0], s: dst_item,
570	val: trans->transid);
571	}
572	}
573	no_copy:
574	btrfs_mark_buffer_dirty(trans, buf: path->nodes[0]);
575	btrfs_release_path(p: path);
576	return 0;
577	}
578
579	static int read_alloc_one_name(struct extent_buffer *eb, void *start, int len,
580	struct fscrypt_str *name)
581	{
582	char *buf;
583
584	buf = kmalloc(size: len, GFP_NOFS);
585	if (!buf)
586	return -ENOMEM;
587
588	read_extent_buffer(eb, dst: buf, start: (unsigned long)start, len);
589	name->name = buf;
590	name->len = len;
591	return 0;
592	}
593
594	/*
595	* simple helper to read an inode off the disk from a given root
596	* This can only be called for subvolume roots and not for the log
597	*/
598	static noinline struct inode *read_one_inode(struct btrfs_root *root,
599	u64 objectid)
600	{
601	struct inode *inode;
602
603	inode = btrfs_iget(s: root->fs_info->sb, ino: objectid, root);
604	if (IS_ERR(ptr: inode))
605	inode = NULL;
606	return inode;
607	}
608
609	/* replays a single extent in 'eb' at 'slot' with 'key' into the
610	* subvolume 'root'. path is released on entry and should be released
611	* on exit.
612	*
613	* extents in the log tree have not been allocated out of the extent
614	* tree yet. So, this completes the allocation, taking a reference
615	* as required if the extent already exists or creating a new extent
616	* if it isn't in the extent allocation tree yet.
617	*
618	* The extent is inserted into the file, dropping any existing extents
619	* from the file that overlap the new one.
620	*/
621	static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
622	struct btrfs_root *root,
623	struct btrfs_path *path,
624	struct extent_buffer *eb, int slot,
625	struct btrfs_key *key)
626	{
627	struct btrfs_drop_extents_args drop_args = { 0 };
628	struct btrfs_fs_info *fs_info = root->fs_info;
629	int found_type;
630	u64 extent_end;
631	u64 start = key->offset;
632	u64 nbytes = 0;
633	struct btrfs_file_extent_item *item;
634	struct inode *inode = NULL;
635	unsigned long size;
636	int ret = 0;
637
638	item = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
639	found_type = btrfs_file_extent_type(eb, s: item);
640
641	if (found_type == BTRFS_FILE_EXTENT_REG ||
642	found_type == BTRFS_FILE_EXTENT_PREALLOC) {
643	nbytes = btrfs_file_extent_num_bytes(eb, s: item);
644	extent_end = start + nbytes;
645
646	/*
647	* We don't add to the inodes nbytes if we are prealloc or a
648	* hole.
649	*/
650	if (btrfs_file_extent_disk_bytenr(eb, s: item) == 0)
651	nbytes = 0;
652	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
653	size = btrfs_file_extent_ram_bytes(eb, s: item);
654	nbytes = btrfs_file_extent_ram_bytes(eb, s: item);
655	extent_end = ALIGN(start + size,
656	fs_info->sectorsize);
657	} else {
658	ret = 0;
659	goto out;
660	}
661
662	inode = read_one_inode(root, objectid: key->objectid);
663	if (!inode) {
664	ret = -EIO;
665	goto out;
666	}
667
668	/*
669	* first check to see if we already have this extent in the
670	* file. This must be done before the btrfs_drop_extents run
671	* so we don't try to drop this extent.
672	*/
673	ret = btrfs_lookup_file_extent(trans, root, path,
674	objectid: btrfs_ino(inode: BTRFS_I(inode)), bytenr: start, mod: 0);
675
676	if (ret == 0 &&
677	(found_type == BTRFS_FILE_EXTENT_REG ||
678	found_type == BTRFS_FILE_EXTENT_PREALLOC)) {
679	struct btrfs_file_extent_item cmp1;
680	struct btrfs_file_extent_item cmp2;
681	struct btrfs_file_extent_item *existing;
682	struct extent_buffer *leaf;
683
684	leaf = path->nodes[0];
685	existing = btrfs_item_ptr(leaf, path->slots[0],
686	struct btrfs_file_extent_item);
687
688	read_extent_buffer(eb, dst: &cmp1, start: (unsigned long)item,
689	len: sizeof(cmp1));
690	read_extent_buffer(eb: leaf, dst: &cmp2, start: (unsigned long)existing,
691	len: sizeof(cmp2));
692
693	/*
694	* we already have a pointer to this exact extent,
695	* we don't have to do anything
696	*/
697	if (memcmp(p: &cmp1, q: &cmp2, size: sizeof(cmp1)) == 0) {
698	btrfs_release_path(p: path);
699	goto out;
700	}
701	}
702	btrfs_release_path(p: path);
703
704	/* drop any overlapping extents */
705	drop_args.start = start;
706	drop_args.end = extent_end;
707	drop_args.drop_cache = true;
708	ret = btrfs_drop_extents(trans, root, inode: BTRFS_I(inode), args: &drop_args);
709	if (ret)
710	goto out;
711
712	if (found_type == BTRFS_FILE_EXTENT_REG ||
713	found_type == BTRFS_FILE_EXTENT_PREALLOC) {
714	u64 offset;
715	unsigned long dest_offset;
716	struct btrfs_key ins;
717
718	if (btrfs_file_extent_disk_bytenr(eb, s: item) == 0 &&
719	btrfs_fs_incompat(fs_info, NO_HOLES))
720	goto update_inode;
721
722	ret = btrfs_insert_empty_item(trans, root, path, key,
723	data_size: sizeof(*item));
724	if (ret)
725	goto out;
726	dest_offset = btrfs_item_ptr_offset(path->nodes[0],
727	path->slots[0]);
728	copy_extent_buffer(dst: path->nodes[0], src: eb, dst_offset: dest_offset,
729	src_offset: (unsigned long)item, len: sizeof(*item));
730
731	ins.objectid = btrfs_file_extent_disk_bytenr(eb, s: item);
732	ins.offset = btrfs_file_extent_disk_num_bytes(eb, s: item);
733	ins.type = BTRFS_EXTENT_ITEM_KEY;
734	offset = key->offset - btrfs_file_extent_offset(eb, s: item);
735
736	/*
737	* Manually record dirty extent, as here we did a shallow
738	* file extent item copy and skip normal backref update,
739	* but modifying extent tree all by ourselves.
740	* So need to manually record dirty extent for qgroup,
741	* as the owner of the file extent changed from log tree
742	* (doesn't affect qgroup) to fs/file tree(affects qgroup)
743	*/
744	ret = btrfs_qgroup_trace_extent(trans,
745	bytenr: btrfs_file_extent_disk_bytenr(eb, s: item),
746	num_bytes: btrfs_file_extent_disk_num_bytes(eb, s: item));
747	if (ret < 0)
748	goto out;
749
750	if (ins.objectid > 0) {
751	struct btrfs_ref ref = { 0 };
752	u64 csum_start;
753	u64 csum_end;
754	LIST_HEAD(ordered_sums);
755
756	/*
757	* is this extent already allocated in the extent
758	* allocation tree? If so, just add a reference
759	*/
760	ret = btrfs_lookup_data_extent(fs_info, start: ins.objectid,
761	len: ins.offset);
762	if (ret < 0) {
763	goto out;
764	} else if (ret == 0) {
765	btrfs_init_generic_ref(generic_ref: &ref,
766	action: BTRFS_ADD_DELAYED_REF,
767	bytenr: ins.objectid, len: ins.offset, parent: 0,
768	owning_root: root->root_key.objectid);
769	btrfs_init_data_ref(generic_ref: &ref,
770	ref_root: root->root_key.objectid,
771	ino: key->objectid, offset, mod_root: 0, skip_qgroup: false);
772	ret = btrfs_inc_extent_ref(trans, generic_ref: &ref);
773	if (ret)
774	goto out;
775	} else {
776	/*
777	* insert the extent pointer in the extent
778	* allocation tree
779	*/
780	ret = btrfs_alloc_logged_file_extent(trans,
781	root_objectid: root->root_key.objectid,
782	owner: key->objectid, offset, ins: &ins);
783	if (ret)
784	goto out;
785	}
786	btrfs_release_path(p: path);
787
788	if (btrfs_file_extent_compression(eb, s: item)) {
789	csum_start = ins.objectid;
790	csum_end = csum_start + ins.offset;
791	} else {
792	csum_start = ins.objectid +
793	btrfs_file_extent_offset(eb, s: item);
794	csum_end = csum_start +
795	btrfs_file_extent_num_bytes(eb, s: item);
796	}
797
798	ret = btrfs_lookup_csums_list(root: root->log_root,
799	start: csum_start, end: csum_end - 1,
800	list: &ordered_sums, search_commit: 0, nowait: false);
801	if (ret)
802	goto out;
803	/*
804	* Now delete all existing cums in the csum root that
805	* cover our range. We do this because we can have an
806	* extent that is completely referenced by one file
807	* extent item and partially referenced by another
808	* file extent item (like after using the clone or
809	* extent_same ioctls). In this case if we end up doing
810	* the replay of the one that partially references the
811	* extent first, and we do not do the csum deletion
812	* below, we can get 2 csum items in the csum tree that
813	* overlap each other. For example, imagine our log has
814	* the two following file extent items:
815	*
816	* key (257 EXTENT_DATA 409600)
817	* extent data disk byte 12845056 nr 102400
818	* extent data offset 20480 nr 20480 ram 102400
819	*
820	* key (257 EXTENT_DATA 819200)
821	* extent data disk byte 12845056 nr 102400
822	* extent data offset 0 nr 102400 ram 102400
823	*
824	* Where the second one fully references the 100K extent
825	* that starts at disk byte 12845056, and the log tree
826	* has a single csum item that covers the entire range
827	* of the extent:
828	*
829	* key (EXTENT_CSUM EXTENT_CSUM 12845056) itemsize 100
830	*
831	* After the first file extent item is replayed, the
832	* csum tree gets the following csum item:
833	*
834	* key (EXTENT_CSUM EXTENT_CSUM 12865536) itemsize 20
835	*
836	* Which covers the 20K sub-range starting at offset 20K
837	* of our extent. Now when we replay the second file
838	* extent item, if we do not delete existing csum items
839	* that cover any of its blocks, we end up getting two
840	* csum items in our csum tree that overlap each other:
841	*
842	* key (EXTENT_CSUM EXTENT_CSUM 12845056) itemsize 100
843	* key (EXTENT_CSUM EXTENT_CSUM 12865536) itemsize 20
844	*
845	* Which is a problem, because after this anyone trying
846	* to lookup up for the checksum of any block of our
847	* extent starting at an offset of 40K or higher, will
848	* end up looking at the second csum item only, which
849	* does not contain the checksum for any block starting
850	* at offset 40K or higher of our extent.
851	*/
852	while (!list_empty(head: &ordered_sums)) {
853	struct btrfs_ordered_sum *sums;
854	struct btrfs_root *csum_root;
855
856	sums = list_entry(ordered_sums.next,
857	struct btrfs_ordered_sum,
858	list);
859	csum_root = btrfs_csum_root(fs_info,
860	bytenr: sums->logical);
861	if (!ret)
862	ret = btrfs_del_csums(trans, root: csum_root,
863	bytenr: sums->logical,
864	len: sums->len);
865	if (!ret)
866	ret = btrfs_csum_file_blocks(trans,
867	root: csum_root,
868	sums);
869	list_del(entry: &sums->list);
870	kfree(objp: sums);
871	}
872	if (ret)
873	goto out;
874	} else {
875	btrfs_release_path(p: path);
876	}
877	} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
878	/* inline extents are easy, we just overwrite them */
879	ret = overwrite_item(trans, root, path, eb, slot, key);
880	if (ret)
881	goto out;
882	}
883
884	ret = btrfs_inode_set_file_extent_range(inode: BTRFS_I(inode), start,
885	len: extent_end - start);
886	if (ret)
887	goto out;
888
889	update_inode:
890	btrfs_update_inode_bytes(inode: BTRFS_I(inode), add_bytes: nbytes, del_bytes: drop_args.bytes_found);
891	ret = btrfs_update_inode(trans, inode: BTRFS_I(inode));
892	out:
893	iput(inode);
894	return ret;
895	}
896
897	static int unlink_inode_for_log_replay(struct btrfs_trans_handle *trans,
898	struct btrfs_inode *dir,
899	struct btrfs_inode *inode,
900	const struct fscrypt_str *name)
901	{
902	int ret;
903
904	ret = btrfs_unlink_inode(trans, dir, inode, name);
905	if (ret)
906	return ret;
907	/*
908	* Whenever we need to check if a name exists or not, we check the
909	* fs/subvolume tree. So after an unlink we must run delayed items, so
910	* that future checks for a name during log replay see that the name
911	* does not exists anymore.
912	*/
913	return btrfs_run_delayed_items(trans);
914	}
915
916	/*
917	* when cleaning up conflicts between the directory names in the
918	* subvolume, directory names in the log and directory names in the
919	* inode back references, we may have to unlink inodes from directories.
920	*
921	* This is a helper function to do the unlink of a specific directory
922	* item
923	*/
924	static noinline int drop_one_dir_item(struct btrfs_trans_handle *trans,
925	struct btrfs_path *path,
926	struct btrfs_inode *dir,
927	struct btrfs_dir_item *di)
928	{
929	struct btrfs_root *root = dir->root;
930	struct inode *inode;
931	struct fscrypt_str name;
932	struct extent_buffer *leaf;
933	struct btrfs_key location;
934	int ret;
935
936	leaf = path->nodes[0];
937
938	btrfs_dir_item_key_to_cpu(eb: leaf, item: di, cpu_key: &location);
939	ret = read_alloc_one_name(eb: leaf, start: di + 1, len: btrfs_dir_name_len(eb: leaf, s: di), name: &name);
940	if (ret)
941	return -ENOMEM;
942
943	btrfs_release_path(p: path);
944
945	inode = read_one_inode(root, objectid: location.objectid);
946	if (!inode) {
947	ret = -EIO;
948	goto out;
949	}
950
951	ret = link_to_fixup_dir(trans, root, path, objectid: location.objectid);
952	if (ret)
953	goto out;
954
955	ret = unlink_inode_for_log_replay(trans, dir, inode: BTRFS_I(inode), name: &name);
956	out:
957	kfree(objp: name.name);
958	iput(inode);
959	return ret;
960	}
961
962	/*
963	* See if a given name and sequence number found in an inode back reference are
964	* already in a directory and correctly point to this inode.
965	*
966	* Returns: < 0 on error, 0 if the directory entry does not exists and 1 if it
967	* exists.
968	*/
969	static noinline int inode_in_dir(struct btrfs_root *root,
970	struct btrfs_path *path,
971	u64 dirid, u64 objectid, u64 index,
972	struct fscrypt_str *name)
973	{
974	struct btrfs_dir_item *di;
975	struct btrfs_key location;
976	int ret = 0;
977
978	di = btrfs_lookup_dir_index_item(NULL, root, path, dir: dirid,
979	index, name, mod: 0);
980	if (IS_ERR(ptr: di)) {
981	ret = PTR_ERR(ptr: di);
982	goto out;
983	} else if (di) {
984	btrfs_dir_item_key_to_cpu(eb: path->nodes[0], item: di, cpu_key: &location);
985	if (location.objectid != objectid)
986	goto out;
987	} else {
988	goto out;
989	}
990
991	btrfs_release_path(p: path);
992	di = btrfs_lookup_dir_item(NULL, root, path, dir: dirid, name, mod: 0);
993	if (IS_ERR(ptr: di)) {
994	ret = PTR_ERR(ptr: di);
995	goto out;
996	} else if (di) {
997	btrfs_dir_item_key_to_cpu(eb: path->nodes[0], item: di, cpu_key: &location);
998	if (location.objectid == objectid)
999	ret = 1;
1000	}
1001	out:
1002	btrfs_release_path(p: path);
1003	return ret;
1004	}
1005
1006	/*
1007	* helper function to check a log tree for a named back reference in
1008	* an inode. This is used to decide if a back reference that is
1009	* found in the subvolume conflicts with what we find in the log.
1010	*
1011	* inode backreferences may have multiple refs in a single item,
1012	* during replay we process one reference at a time, and we don't
1013	* want to delete valid links to a file from the subvolume if that
1014	* link is also in the log.
1015	*/
1016	static noinline int backref_in_log(struct btrfs_root *log,
1017	struct btrfs_key *key,
1018	u64 ref_objectid,
1019	const struct fscrypt_str *name)
1020	{
1021	struct btrfs_path *path;
1022	int ret;
1023
1024	path = btrfs_alloc_path();
1025	if (!path)
1026	return -ENOMEM;
1027
1028	ret = btrfs_search_slot(NULL, root: log, key, p: path, ins_len: 0, cow: 0);
1029	if (ret < 0) {
1030	goto out;
1031	} else if (ret == 1) {
1032	ret = 0;
1033	goto out;
1034	}
1035
1036	if (key->type == BTRFS_INODE_EXTREF_KEY)
1037	ret = !!btrfs_find_name_in_ext_backref(leaf: path->nodes[0],
1038	slot: path->slots[0],
1039	ref_objectid, name);
1040	else
1041	ret = !!btrfs_find_name_in_backref(leaf: path->nodes[0],
1042	slot: path->slots[0], name);
1043	out:
1044	btrfs_free_path(p: path);
1045	return ret;
1046	}
1047
1048	static inline int __add_inode_ref(struct btrfs_trans_handle *trans,
1049	struct btrfs_root *root,
1050	struct btrfs_path *path,
1051	struct btrfs_root *log_root,
1052	struct btrfs_inode *dir,
1053	struct btrfs_inode *inode,
1054	u64 inode_objectid, u64 parent_objectid,
1055	u64 ref_index, struct fscrypt_str *name)
1056	{
1057	int ret;
1058	struct extent_buffer *leaf;
1059	struct btrfs_dir_item *di;
1060	struct btrfs_key search_key;
1061	struct btrfs_inode_extref *extref;
1062
1063	again:
1064	/* Search old style refs */
1065	search_key.objectid = inode_objectid;
1066	search_key.type = BTRFS_INODE_REF_KEY;
1067	search_key.offset = parent_objectid;
1068	ret = btrfs_search_slot(NULL, root, key: &search_key, p: path, ins_len: 0, cow: 0);
1069	if (ret == 0) {
1070	struct btrfs_inode_ref *victim_ref;
1071	unsigned long ptr;
1072	unsigned long ptr_end;
1073
1074	leaf = path->nodes[0];
1075
1076	/* are we trying to overwrite a back ref for the root directory
1077	* if so, just jump out, we're done
1078	*/
1079	if (search_key.objectid == search_key.offset)
1080	return 1;
1081
1082	/* check all the names in this back reference to see
1083	* if they are in the log. if so, we allow them to stay
1084	* otherwise they must be unlinked as a conflict
1085	*/
1086	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1087	ptr_end = ptr + btrfs_item_size(eb: leaf, slot: path->slots[0]);
1088	while (ptr < ptr_end) {
1089	struct fscrypt_str victim_name;
1090
1091	victim_ref = (struct btrfs_inode_ref *)ptr;
1092	ret = read_alloc_one_name(eb: leaf, start: (victim_ref + 1),
1093	len: btrfs_inode_ref_name_len(eb: leaf, s: victim_ref),
1094	name: &victim_name);
1095	if (ret)
1096	return ret;
1097
1098	ret = backref_in_log(log: log_root, key: &search_key,
1099	ref_objectid: parent_objectid, name: &victim_name);
1100	if (ret < 0) {
1101	kfree(objp: victim_name.name);
1102	return ret;
1103	} else if (!ret) {
1104	inc_nlink(inode: &inode->vfs_inode);
1105	btrfs_release_path(p: path);
1106
1107	ret = unlink_inode_for_log_replay(trans, dir, inode,
1108	name: &victim_name);
1109	kfree(objp: victim_name.name);
1110	if (ret)
1111	return ret;
1112	goto again;
1113	}
1114	kfree(objp: victim_name.name);
1115
1116	ptr = (unsigned long)(victim_ref + 1) + victim_name.len;
1117	}
1118	}
1119	btrfs_release_path(p: path);
1120
1121	/* Same search but for extended refs */
1122	extref = btrfs_lookup_inode_extref(NULL, root, path, name,
1123	inode_objectid, ref_objectid: parent_objectid, ins_len: 0,
1124	cow: 0);
1125	if (IS_ERR(ptr: extref)) {
1126	return PTR_ERR(ptr: extref);
1127	} else if (extref) {
1128	u32 item_size;
1129	u32 cur_offset = 0;
1130	unsigned long base;
1131	struct inode *victim_parent;
1132
1133	leaf = path->nodes[0];
1134
1135	item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]);
1136	base = btrfs_item_ptr_offset(leaf, path->slots[0]);
1137
1138	while (cur_offset < item_size) {
1139	struct fscrypt_str victim_name;
1140
1141	extref = (struct btrfs_inode_extref *)(base + cur_offset);
1142
1143	if (btrfs_inode_extref_parent(eb: leaf, s: extref) != parent_objectid)
1144	goto next;
1145
1146	ret = read_alloc_one_name(eb: leaf, start: &extref->name,
1147	len: btrfs_inode_extref_name_len(eb: leaf, s: extref),
1148	name: &victim_name);
1149	if (ret)
1150	return ret;
1151
1152	search_key.objectid = inode_objectid;
1153	search_key.type = BTRFS_INODE_EXTREF_KEY;
1154	search_key.offset = btrfs_extref_hash(parent_objectid,
1155	name: victim_name.name,
1156	len: victim_name.len);
1157	ret = backref_in_log(log: log_root, key: &search_key,
1158	ref_objectid: parent_objectid, name: &victim_name);
1159	if (ret < 0) {
1160	kfree(objp: victim_name.name);
1161	return ret;
1162	} else if (!ret) {
1163	ret = -ENOENT;
1164	victim_parent = read_one_inode(root,
1165	objectid: parent_objectid);
1166	if (victim_parent) {
1167	inc_nlink(inode: &inode->vfs_inode);
1168	btrfs_release_path(p: path);
1169
1170	ret = unlink_inode_for_log_replay(trans,
1171	dir: BTRFS_I(inode: victim_parent),
1172	inode, name: &victim_name);
1173	}
1174	iput(victim_parent);
1175	kfree(objp: victim_name.name);
1176	if (ret)
1177	return ret;
1178	goto again;
1179	}
1180	kfree(objp: victim_name.name);
1181	next:
1182	cur_offset += victim_name.len + sizeof(*extref);
1183	}
1184	}
1185	btrfs_release_path(p: path);
1186
1187	/* look for a conflicting sequence number */
1188	di = btrfs_lookup_dir_index_item(trans, root, path, dir: btrfs_ino(inode: dir),
1189	index: ref_index, name, mod: 0);
1190	if (IS_ERR(ptr: di)) {
1191	return PTR_ERR(ptr: di);
1192	} else if (di) {
1193	ret = drop_one_dir_item(trans, path, dir, di);
1194	if (ret)
1195	return ret;
1196	}
1197	btrfs_release_path(p: path);
1198
1199	/* look for a conflicting name */
1200	di = btrfs_lookup_dir_item(trans, root, path, dir: btrfs_ino(inode: dir), name, mod: 0);
1201	if (IS_ERR(ptr: di)) {
1202	return PTR_ERR(ptr: di);
1203	} else if (di) {
1204	ret = drop_one_dir_item(trans, path, dir, di);
1205	if (ret)
1206	return ret;
1207	}
1208	btrfs_release_path(p: path);
1209
1210	return 0;
1211	}
1212
1213	static int extref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr,
1214	struct fscrypt_str *name, u64 *index,
1215	u64 *parent_objectid)
1216	{
1217	struct btrfs_inode_extref *extref;
1218	int ret;
1219
1220	extref = (struct btrfs_inode_extref *)ref_ptr;
1221
1222	ret = read_alloc_one_name(eb, start: &extref->name,
1223	len: btrfs_inode_extref_name_len(eb, s: extref), name);
1224	if (ret)
1225	return ret;
1226
1227	if (index)
1228	*index = btrfs_inode_extref_index(eb, s: extref);
1229	if (parent_objectid)
1230	*parent_objectid = btrfs_inode_extref_parent(eb, s: extref);
1231
1232	return 0;
1233	}
1234
1235	static int ref_get_fields(struct extent_buffer *eb, unsigned long ref_ptr,
1236	struct fscrypt_str *name, u64 *index)
1237	{
1238	struct btrfs_inode_ref *ref;
1239	int ret;
1240
1241	ref = (struct btrfs_inode_ref *)ref_ptr;
1242
1243	ret = read_alloc_one_name(eb, start: ref + 1, len: btrfs_inode_ref_name_len(eb, s: ref),
1244	name);
1245	if (ret)
1246	return ret;
1247
1248	if (index)
1249	*index = btrfs_inode_ref_index(eb, s: ref);
1250
1251	return 0;
1252	}
1253
1254	/*
1255	* Take an inode reference item from the log tree and iterate all names from the
1256	* inode reference item in the subvolume tree with the same key (if it exists).
1257	* For any name that is not in the inode reference item from the log tree, do a
1258	* proper unlink of that name (that is, remove its entry from the inode
1259	* reference item and both dir index keys).
1260	*/
1261	static int unlink_old_inode_refs(struct btrfs_trans_handle *trans,
1262	struct btrfs_root *root,
1263	struct btrfs_path *path,
1264	struct btrfs_inode *inode,
1265	struct extent_buffer *log_eb,
1266	int log_slot,
1267	struct btrfs_key *key)
1268	{
1269	int ret;
1270	unsigned long ref_ptr;
1271	unsigned long ref_end;
1272	struct extent_buffer *eb;
1273
1274	again:
1275	btrfs_release_path(p: path);
1276	ret = btrfs_search_slot(NULL, root, key, p: path, ins_len: 0, cow: 0);
1277	if (ret > 0) {
1278	ret = 0;
1279	goto out;
1280	}
1281	if (ret < 0)
1282	goto out;
1283
1284	eb = path->nodes[0];
1285	ref_ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
1286	ref_end = ref_ptr + btrfs_item_size(eb, slot: path->slots[0]);
1287	while (ref_ptr < ref_end) {
1288	struct fscrypt_str name;
1289	u64 parent_id;
1290
1291	if (key->type == BTRFS_INODE_EXTREF_KEY) {
1292	ret = extref_get_fields(eb, ref_ptr, name: &name,
1293	NULL, parent_objectid: &parent_id);
1294	} else {
1295	parent_id = key->offset;
1296	ret = ref_get_fields(eb, ref_ptr, name: &name, NULL);
1297	}
1298	if (ret)
1299	goto out;
1300
1301	if (key->type == BTRFS_INODE_EXTREF_KEY)
1302	ret = !!btrfs_find_name_in_ext_backref(leaf: log_eb, slot: log_slot,
1303	ref_objectid: parent_id, name: &name);
1304	else
1305	ret = !!btrfs_find_name_in_backref(leaf: log_eb, slot: log_slot, name: &name);
1306
1307	if (!ret) {
1308	struct inode *dir;
1309
1310	btrfs_release_path(p: path);
1311	dir = read_one_inode(root, objectid: parent_id);
1312	if (!dir) {
1313	ret = -ENOENT;
1314	kfree(objp: name.name);
1315	goto out;
1316	}
1317	ret = unlink_inode_for_log_replay(trans, dir: BTRFS_I(inode: dir),
1318	inode, name: &name);
1319	kfree(objp: name.name);
1320	iput(dir);
1321	if (ret)
1322	goto out;
1323	goto again;
1324	}
1325
1326	kfree(objp: name.name);
1327	ref_ptr += name.len;
1328	if (key->type == BTRFS_INODE_EXTREF_KEY)
1329	ref_ptr += sizeof(struct btrfs_inode_extref);
1330	else
1331	ref_ptr += sizeof(struct btrfs_inode_ref);
1332	}
1333	ret = 0;
1334	out:
1335	btrfs_release_path(p: path);
1336	return ret;
1337	}
1338
1339	/*
1340	* replay one inode back reference item found in the log tree.
1341	* eb, slot and key refer to the buffer and key found in the log tree.
1342	* root is the destination we are replaying into, and path is for temp
1343	* use by this function. (it should be released on return).
1344	*/
1345	static noinline int add_inode_ref(struct btrfs_trans_handle *trans,
1346	struct btrfs_root *root,
1347	struct btrfs_root *log,
1348	struct btrfs_path *path,
1349	struct extent_buffer *eb, int slot,
1350	struct btrfs_key *key)
1351	{
1352	struct inode *dir = NULL;
1353	struct inode *inode = NULL;
1354	unsigned long ref_ptr;
1355	unsigned long ref_end;
1356	struct fscrypt_str name;
1357	int ret;
1358	int log_ref_ver = 0;
1359	u64 parent_objectid;
1360	u64 inode_objectid;
1361	u64 ref_index = 0;
1362	int ref_struct_size;
1363
1364	ref_ptr = btrfs_item_ptr_offset(eb, slot);
1365	ref_end = ref_ptr + btrfs_item_size(eb, slot);
1366
1367	if (key->type == BTRFS_INODE_EXTREF_KEY) {
1368	struct btrfs_inode_extref *r;
1369
1370	ref_struct_size = sizeof(struct btrfs_inode_extref);
1371	log_ref_ver = 1;
1372	r = (struct btrfs_inode_extref *)ref_ptr;
1373	parent_objectid = btrfs_inode_extref_parent(eb, s: r);
1374	} else {
1375	ref_struct_size = sizeof(struct btrfs_inode_ref);
1376	parent_objectid = key->offset;
1377	}
1378	inode_objectid = key->objectid;
1379
1380	/*
1381	* it is possible that we didn't log all the parent directories
1382	* for a given inode. If we don't find the dir, just don't
1383	* copy the back ref in. The link count fixup code will take
1384	* care of the rest
1385	*/
1386	dir = read_one_inode(root, objectid: parent_objectid);
1387	if (!dir) {
1388	ret = -ENOENT;
1389	goto out;
1390	}
1391
1392	inode = read_one_inode(root, objectid: inode_objectid);
1393	if (!inode) {
1394	ret = -EIO;
1395	goto out;
1396	}
1397
1398	while (ref_ptr < ref_end) {
1399	if (log_ref_ver) {
1400	ret = extref_get_fields(eb, ref_ptr, name: &name,
1401	index: &ref_index, parent_objectid: &parent_objectid);
1402	/*
1403	* parent object can change from one array
1404	* item to another.
1405	*/
1406	if (!dir)
1407	dir = read_one_inode(root, objectid: parent_objectid);
1408	if (!dir) {
1409	ret = -ENOENT;
1410	goto out;
1411	}
1412	} else {
1413	ret = ref_get_fields(eb, ref_ptr, name: &name, index: &ref_index);
1414	}
1415	if (ret)
1416	goto out;
1417
1418	ret = inode_in_dir(root, path, dirid: btrfs_ino(inode: BTRFS_I(inode: dir)),
1419	objectid: btrfs_ino(inode: BTRFS_I(inode)), index: ref_index, name: &name);
1420	if (ret < 0) {
1421	goto out;
1422	} else if (ret == 0) {
1423	/*
1424	* look for a conflicting back reference in the
1425	* metadata. if we find one we have to unlink that name
1426	* of the file before we add our new link. Later on, we
1427	* overwrite any existing back reference, and we don't
1428	* want to create dangling pointers in the directory.
1429	*/
1430	ret = __add_inode_ref(trans, root, path, log_root: log,
1431	dir: BTRFS_I(inode: dir), inode: BTRFS_I(inode),
1432	inode_objectid, parent_objectid,
1433	ref_index, name: &name);
1434	if (ret) {
1435	if (ret == 1)
1436	ret = 0;
1437	goto out;
1438	}
1439
1440	/* insert our name */
1441	ret = btrfs_add_link(trans, parent_inode: BTRFS_I(inode: dir), inode: BTRFS_I(inode),
1442	name: &name, add_backref: 0, index: ref_index);
1443	if (ret)
1444	goto out;
1445
1446	ret = btrfs_update_inode(trans, inode: BTRFS_I(inode));
1447	if (ret)
1448	goto out;
1449	}
1450	/* Else, ret == 1, we already have a perfect match, we're done. */
1451
1452	ref_ptr = (unsigned long)(ref_ptr + ref_struct_size) + name.len;
1453	kfree(objp: name.name);
1454	name.name = NULL;
1455	if (log_ref_ver) {
1456	iput(dir);
1457	dir = NULL;
1458	}
1459	}
1460
1461	/*
1462	* Before we overwrite the inode reference item in the subvolume tree
1463	* with the item from the log tree, we must unlink all names from the
1464	* parent directory that are in the subvolume's tree inode reference
1465	* item, otherwise we end up with an inconsistent subvolume tree where
1466	* dir index entries exist for a name but there is no inode reference
1467	* item with the same name.
1468	*/
1469	ret = unlink_old_inode_refs(trans, root, path, inode: BTRFS_I(inode), log_eb: eb, log_slot: slot,
1470	key);
1471	if (ret)
1472	goto out;
1473
1474	/* finally write the back reference in the inode */
1475	ret = overwrite_item(trans, root, path, eb, slot, key);
1476	out:
1477	btrfs_release_path(p: path);
1478	kfree(objp: name.name);
1479	iput(dir);
1480	iput(inode);
1481	return ret;
1482	}
1483
1484	static int count_inode_extrefs(struct btrfs_inode *inode, struct btrfs_path *path)
1485	{
1486	int ret = 0;
1487	int name_len;
1488	unsigned int nlink = 0;
1489	u32 item_size;
1490	u32 cur_offset = 0;
1491	u64 inode_objectid = btrfs_ino(inode);
1492	u64 offset = 0;
1493	unsigned long ptr;
1494	struct btrfs_inode_extref *extref;
1495	struct extent_buffer *leaf;
1496
1497	while (1) {
1498	ret = btrfs_find_one_extref(root: inode->root, inode_objectid, start_off: offset,
1499	path, ret_extref: &extref, found_off: &offset);
1500	if (ret)
1501	break;
1502
1503	leaf = path->nodes[0];
1504	item_size = btrfs_item_size(eb: leaf, slot: path->slots[0]);
1505	ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
1506	cur_offset = 0;
1507
1508	while (cur_offset < item_size) {
1509	extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
1510	name_len = btrfs_inode_extref_name_len(eb: leaf, s: extref);
1511
1512	nlink++;
1513
1514	cur_offset += name_len + sizeof(*extref);
1515	}
1516
1517	offset++;
1518	btrfs_release_path(p: path);
1519	}
1520	btrfs_release_path(p: path);
1521
1522	if (ret < 0 && ret != -ENOENT)
1523	return ret;
1524	return nlink;
1525	}
1526
1527	static int count_inode_refs(struct btrfs_inode *inode, struct btrfs_path *path)
1528	{
1529	int ret;
1530	struct btrfs_key key;
1531	unsigned int nlink = 0;
1532	unsigned long ptr;
1533	unsigned long ptr_end;
1534	int name_len;
1535	u64 ino = btrfs_ino(inode);
1536
1537	key.objectid = ino;
1538	key.type = BTRFS_INODE_REF_KEY;
1539	key.offset = (u64)-1;
1540
1541	while (1) {
1542	ret = btrfs_search_slot(NULL, root: inode->root, key: &key, p: path, ins_len: 0, cow: 0);
1543	if (ret < 0)
1544	break;
1545	if (ret > 0) {
1546	if (path->slots[0] == 0)
1547	break;
1548	path->slots[0]--;
1549	}
1550	process_slot:
1551	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key,
1552	nr: path->slots[0]);
1553	if (key.objectid != ino ||
1554	key.type != BTRFS_INODE_REF_KEY)
1555	break;
1556	ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
1557	ptr_end = ptr + btrfs_item_size(eb: path->nodes[0],
1558	slot: path->slots[0]);
1559	while (ptr < ptr_end) {
1560	struct btrfs_inode_ref *ref;
1561
1562	ref = (struct btrfs_inode_ref *)ptr;
1563	name_len = btrfs_inode_ref_name_len(eb: path->nodes[0],
1564	s: ref);
1565	ptr = (unsigned long)(ref + 1) + name_len;
1566	nlink++;
1567	}
1568
1569	if (key.offset == 0)
1570	break;
1571	if (path->slots[0] > 0) {
1572	path->slots[0]--;
1573	goto process_slot;
1574	}
1575	key.offset--;
1576	btrfs_release_path(p: path);
1577	}
1578	btrfs_release_path(p: path);
1579
1580	return nlink;
1581	}
1582
1583	/*
1584	* There are a few corners where the link count of the file can't
1585	* be properly maintained during replay. So, instead of adding
1586	* lots of complexity to the log code, we just scan the backrefs
1587	* for any file that has been through replay.
1588	*
1589	* The scan will update the link count on the inode to reflect the
1590	* number of back refs found. If it goes down to zero, the iput
1591	* will free the inode.
1592	*/
1593	static noinline int fixup_inode_link_count(struct btrfs_trans_handle *trans,
1594	struct inode *inode)
1595	{
1596	struct btrfs_root *root = BTRFS_I(inode)->root;
1597	struct btrfs_path *path;
1598	int ret;
1599	u64 nlink = 0;
1600	u64 ino = btrfs_ino(inode: BTRFS_I(inode));
1601
1602	path = btrfs_alloc_path();
1603	if (!path)
1604	return -ENOMEM;
1605
1606	ret = count_inode_refs(inode: BTRFS_I(inode), path);
1607	if (ret < 0)
1608	goto out;
1609
1610	nlink = ret;
1611
1612	ret = count_inode_extrefs(inode: BTRFS_I(inode), path);
1613	if (ret < 0)
1614	goto out;
1615
1616	nlink += ret;
1617
1618	ret = 0;
1619
1620	if (nlink != inode->i_nlink) {
1621	set_nlink(inode, nlink);
1622	ret = btrfs_update_inode(trans, inode: BTRFS_I(inode));
1623	if (ret)
1624	goto out;
1625	}
1626	BTRFS_I(inode)->index_cnt = (u64)-1;
1627
1628	if (inode->i_nlink == 0) {
1629	if (S_ISDIR(inode->i_mode)) {
1630	ret = replay_dir_deletes(trans, root, NULL, path,
1631	dirid: ino, del_all: 1);
1632	if (ret)
1633	goto out;
1634	}
1635	ret = btrfs_insert_orphan_item(trans, root, offset: ino);
1636	if (ret == -EEXIST)
1637	ret = 0;
1638	}
1639
1640	out:
1641	btrfs_free_path(p: path);
1642	return ret;
1643	}
1644
1645	static noinline int fixup_inode_link_counts(struct btrfs_trans_handle *trans,
1646	struct btrfs_root *root,
1647	struct btrfs_path *path)
1648	{
1649	int ret;
1650	struct btrfs_key key;
1651	struct inode *inode;
1652
1653	key.objectid = BTRFS_TREE_LOG_FIXUP_OBJECTID;
1654	key.type = BTRFS_ORPHAN_ITEM_KEY;
1655	key.offset = (u64)-1;
1656	while (1) {
1657	ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1);
1658	if (ret < 0)
1659	break;
1660
1661	if (ret == 1) {
1662	ret = 0;
1663	if (path->slots[0] == 0)
1664	break;
1665	path->slots[0]--;
1666	}
1667
1668	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]);
1669	if (key.objectid != BTRFS_TREE_LOG_FIXUP_OBJECTID ||
1670	key.type != BTRFS_ORPHAN_ITEM_KEY)
1671	break;
1672
1673	ret = btrfs_del_item(trans, root, path);
1674	if (ret)
1675	break;
1676
1677	btrfs_release_path(p: path);
1678	inode = read_one_inode(root, objectid: key.offset);
1679	if (!inode) {
1680	ret = -EIO;
1681	break;
1682	}
1683
1684	ret = fixup_inode_link_count(trans, inode);
1685	iput(inode);
1686	if (ret)
1687	break;
1688
1689	/*
1690	* fixup on a directory may create new entries,
1691	* make sure we always look for the highset possible
1692	* offset
1693	*/
1694	key.offset = (u64)-1;
1695	}
1696	btrfs_release_path(p: path);
1697	return ret;
1698	}
1699
1700
1701	/*
1702	* record a given inode in the fixup dir so we can check its link
1703	* count when replay is done. The link count is incremented here
1704	* so the inode won't go away until we check it
1705	*/
1706	static noinline int link_to_fixup_dir(struct btrfs_trans_handle *trans,
1707	struct btrfs_root *root,
1708	struct btrfs_path *path,
1709	u64 objectid)
1710	{
1711	struct btrfs_key key;
1712	int ret = 0;
1713	struct inode *inode;
1714
1715	inode = read_one_inode(root, objectid);
1716	if (!inode)
1717	return -EIO;
1718
1719	key.objectid = BTRFS_TREE_LOG_FIXUP_OBJECTID;
1720	key.type = BTRFS_ORPHAN_ITEM_KEY;
1721	key.offset = objectid;
1722
1723	ret = btrfs_insert_empty_item(trans, root, path, key: &key, data_size: 0);
1724
1725	btrfs_release_path(p: path);
1726	if (ret == 0) {
1727	if (!inode->i_nlink)
1728	set_nlink(inode, nlink: 1);
1729	else
1730	inc_nlink(inode);
1731	ret = btrfs_update_inode(trans, inode: BTRFS_I(inode));
1732	} else if (ret == -EEXIST) {
1733	ret = 0;
1734	}
1735	iput(inode);
1736
1737	return ret;
1738	}
1739
1740	/*
1741	* when replaying the log for a directory, we only insert names
1742	* for inodes that actually exist. This means an fsync on a directory
1743	* does not implicitly fsync all the new files in it
1744	*/
1745	static noinline int insert_one_name(struct btrfs_trans_handle *trans,
1746	struct btrfs_root *root,
1747	u64 dirid, u64 index,
1748	const struct fscrypt_str *name,
1749	struct btrfs_key *location)
1750	{
1751	struct inode *inode;
1752	struct inode *dir;
1753	int ret;
1754
1755	inode = read_one_inode(root, objectid: location->objectid);
1756	if (!inode)
1757	return -ENOENT;
1758
1759	dir = read_one_inode(root, objectid: dirid);
1760	if (!dir) {
1761	iput(inode);
1762	return -EIO;
1763	}
1764
1765	ret = btrfs_add_link(trans, parent_inode: BTRFS_I(inode: dir), inode: BTRFS_I(inode), name,
1766	add_backref: 1, index);
1767
1768	/* FIXME, put inode into FIXUP list */
1769
1770	iput(inode);
1771	iput(dir);
1772	return ret;
1773	}
1774
1775	static int delete_conflicting_dir_entry(struct btrfs_trans_handle *trans,
1776	struct btrfs_inode *dir,
1777	struct btrfs_path *path,
1778	struct btrfs_dir_item *dst_di,
1779	const struct btrfs_key *log_key,
1780	u8 log_flags,
1781	bool exists)
1782	{
1783	struct btrfs_key found_key;
1784
1785	btrfs_dir_item_key_to_cpu(eb: path->nodes[0], item: dst_di, cpu_key: &found_key);
1786	/* The existing dentry points to the same inode, don't delete it. */
1787	if (found_key.objectid == log_key->objectid &&
1788	found_key.type == log_key->type &&
1789	found_key.offset == log_key->offset &&
1790	btrfs_dir_flags(eb: path->nodes[0], s: dst_di) == log_flags)
1791	return 1;
1792
1793	/*
1794	* Don't drop the conflicting directory entry if the inode for the new
1795	* entry doesn't exist.
1796	*/
1797	if (!exists)
1798	return 0;
1799
1800	return drop_one_dir_item(trans, path, dir, di: dst_di);
1801	}
1802
1803	/*
1804	* take a single entry in a log directory item and replay it into
1805	* the subvolume.
1806	*
1807	* if a conflicting item exists in the subdirectory already,
1808	* the inode it points to is unlinked and put into the link count
1809	* fix up tree.
1810	*
1811	* If a name from the log points to a file or directory that does
1812	* not exist in the FS, it is skipped. fsyncs on directories
1813	* do not force down inodes inside that directory, just changes to the
1814	* names or unlinks in a directory.
1815	*
1816	* Returns < 0 on error, 0 if the name wasn't replayed (dentry points to a
1817	* non-existing inode) and 1 if the name was replayed.
1818	*/
1819	static noinline int replay_one_name(struct btrfs_trans_handle *trans,
1820	struct btrfs_root *root,
1821	struct btrfs_path *path,
1822	struct extent_buffer *eb,
1823	struct btrfs_dir_item *di,
1824	struct btrfs_key *key)
1825	{
1826	struct fscrypt_str name;
1827	struct btrfs_dir_item *dir_dst_di;
1828	struct btrfs_dir_item *index_dst_di;
1829	bool dir_dst_matches = false;
1830	bool index_dst_matches = false;
1831	struct btrfs_key log_key;
1832	struct btrfs_key search_key;
1833	struct inode *dir;
1834	u8 log_flags;
1835	bool exists;
1836	int ret;
1837	bool update_size = true;
1838	bool name_added = false;
1839
1840	dir = read_one_inode(root, objectid: key->objectid);
1841	if (!dir)
1842	return -EIO;
1843
1844	ret = read_alloc_one_name(eb, start: di + 1, len: btrfs_dir_name_len(eb, s: di), name: &name);
1845	if (ret)
1846	goto out;
1847
1848	log_flags = btrfs_dir_flags(eb, s: di);
1849	btrfs_dir_item_key_to_cpu(eb, item: di, cpu_key: &log_key);
1850	ret = btrfs_lookup_inode(trans, root, path, location: &log_key, mod: 0);
1851	btrfs_release_path(p: path);
1852	if (ret < 0)
1853	goto out;
1854	exists = (ret == 0);
1855	ret = 0;
1856
1857	dir_dst_di = btrfs_lookup_dir_item(trans, root, path, dir: key->objectid,
1858	name: &name, mod: 1);
1859	if (IS_ERR(ptr: dir_dst_di)) {
1860	ret = PTR_ERR(ptr: dir_dst_di);
1861	goto out;
1862	} else if (dir_dst_di) {
1863	ret = delete_conflicting_dir_entry(trans, dir: BTRFS_I(inode: dir), path,
1864	dst_di: dir_dst_di, log_key: &log_key,
1865	log_flags, exists);
1866	if (ret < 0)
1867	goto out;
1868	dir_dst_matches = (ret == 1);
1869	}
1870
1871	btrfs_release_path(p: path);
1872
1873	index_dst_di = btrfs_lookup_dir_index_item(trans, root, path,
1874	dir: key->objectid, index: key->offset,
1875	name: &name, mod: 1);
1876	if (IS_ERR(ptr: index_dst_di)) {
1877	ret = PTR_ERR(ptr: index_dst_di);
1878	goto out;
1879	} else if (index_dst_di) {
1880	ret = delete_conflicting_dir_entry(trans, dir: BTRFS_I(inode: dir), path,
1881	dst_di: index_dst_di, log_key: &log_key,
1882	log_flags, exists);
1883	if (ret < 0)
1884	goto out;
1885	index_dst_matches = (ret == 1);
1886	}
1887
1888	btrfs_release_path(p: path);
1889
1890	if (dir_dst_matches && index_dst_matches) {
1891	ret = 0;
1892	update_size = false;
1893	goto out;
1894	}
1895
1896	/*
1897	* Check if the inode reference exists in the log for the given name,
1898	* inode and parent inode
1899	*/
1900	search_key.objectid = log_key.objectid;
1901	search_key.type = BTRFS_INODE_REF_KEY;
1902	search_key.offset = key->objectid;
1903	ret = backref_in_log(log: root->log_root, key: &search_key, ref_objectid: 0, name: &name);
1904	if (ret < 0) {
1905	goto out;
1906	} else if (ret) {
1907	/* The dentry will be added later. */
1908	ret = 0;
1909	update_size = false;
1910	goto out;
1911	}
1912
1913	search_key.objectid = log_key.objectid;
1914	search_key.type = BTRFS_INODE_EXTREF_KEY;
1915	search_key.offset = key->objectid;
1916	ret = backref_in_log(log: root->log_root, key: &search_key, ref_objectid: key->objectid, name: &name);
1917	if (ret < 0) {
1918	goto out;
1919	} else if (ret) {
1920	/* The dentry will be added later. */
1921	ret = 0;
1922	update_size = false;
1923	goto out;
1924	}
1925	btrfs_release_path(p: path);
1926	ret = insert_one_name(trans, root, dirid: key->objectid, index: key->offset,
1927	name: &name, location: &log_key);
1928	if (ret && ret != -ENOENT && ret != -EEXIST)
1929	goto out;
1930	if (!ret)
1931	name_added = true;
1932	update_size = false;
1933	ret = 0;
1934
1935	out:
1936	if (!ret && update_size) {
1937	btrfs_i_size_write(inode: BTRFS_I(inode: dir), size: dir->i_size + name.len * 2);
1938	ret = btrfs_update_inode(trans, inode: BTRFS_I(inode: dir));
1939	}
1940	kfree(objp: name.name);
1941	iput(dir);
1942	if (!ret && name_added)
1943	ret = 1;
1944	return ret;
1945	}
1946
1947	/* Replay one dir item from a BTRFS_DIR_INDEX_KEY key. */
1948	static noinline int replay_one_dir_item(struct btrfs_trans_handle *trans,
1949	struct btrfs_root *root,
1950	struct btrfs_path *path,
1951	struct extent_buffer *eb, int slot,
1952	struct btrfs_key *key)
1953	{
1954	int ret;
1955	struct btrfs_dir_item *di;
1956
1957	/* We only log dir index keys, which only contain a single dir item. */
1958	ASSERT(key->type == BTRFS_DIR_INDEX_KEY);
1959
1960	di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
1961	ret = replay_one_name(trans, root, path, eb, di, key);
1962	if (ret < 0)
1963	return ret;
1964
1965	/*
1966	* If this entry refers to a non-directory (directories can not have a
1967	* link count > 1) and it was added in the transaction that was not
1968	* committed, make sure we fixup the link count of the inode the entry
1969	* points to. Otherwise something like the following would result in a
1970	* directory pointing to an inode with a wrong link that does not account
1971	* for this dir entry:
1972	*
1973	* mkdir testdir
1974	* touch testdir/foo
1975	* touch testdir/bar
1976	* sync
1977	*
1978	* ln testdir/bar testdir/bar_link
1979	* ln testdir/foo testdir/foo_link
1980	* xfs_io -c "fsync" testdir/bar
1981	*
1982	* <power failure>
1983	*
1984	* mount fs, log replay happens
1985	*
1986	* File foo would remain with a link count of 1 when it has two entries
1987	* pointing to it in the directory testdir. This would make it impossible
1988	* to ever delete the parent directory has it would result in stale
1989	* dentries that can never be deleted.
1990	*/
1991	if (ret == 1 && btrfs_dir_ftype(eb, item: di) != BTRFS_FT_DIR) {
1992	struct btrfs_path *fixup_path;
1993	struct btrfs_key di_key;
1994
1995	fixup_path = btrfs_alloc_path();
1996	if (!fixup_path)
1997	return -ENOMEM;
1998
1999	btrfs_dir_item_key_to_cpu(eb, item: di, cpu_key: &di_key);
2000	ret = link_to_fixup_dir(trans, root, path: fixup_path, objectid: di_key.objectid);
2001	btrfs_free_path(p: fixup_path);
2002	}
2003
2004	return ret;
2005	}
2006
2007	/*
2008	* directory replay has two parts. There are the standard directory
2009	* items in the log copied from the subvolume, and range items
2010	* created in the log while the subvolume was logged.
2011	*
2012	* The range items tell us which parts of the key space the log
2013	* is authoritative for. During replay, if a key in the subvolume
2014	* directory is in a logged range item, but not actually in the log
2015	* that means it was deleted from the directory before the fsync
2016	* and should be removed.
2017	*/
2018	static noinline int find_dir_range(struct btrfs_root *root,
2019	struct btrfs_path *path,
2020	u64 dirid,
2021	u64 *start_ret, u64 *end_ret)
2022	{
2023	struct btrfs_key key;
2024	u64 found_end;
2025	struct btrfs_dir_log_item *item;
2026	int ret;
2027	int nritems;
2028
2029	if (*start_ret == (u64)-1)
2030	return 1;
2031
2032	key.objectid = dirid;
2033	key.type = BTRFS_DIR_LOG_INDEX_KEY;
2034	key.offset = *start_ret;
2035
2036	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
2037	if (ret < 0)
2038	goto out;
2039	if (ret > 0) {
2040	if (path->slots[0] == 0)
2041	goto out;
2042	path->slots[0]--;
2043	}
2044	if (ret != 0)
2045	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]);
2046
2047	if (key.type != BTRFS_DIR_LOG_INDEX_KEY || key.objectid != dirid) {
2048	ret = 1;
2049	goto next;
2050	}
2051	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2052	struct btrfs_dir_log_item);
2053	found_end = btrfs_dir_log_end(eb: path->nodes[0], s: item);
2054
2055	if (*start_ret >= key.offset && *start_ret <= found_end) {
2056	ret = 0;
2057	*start_ret = key.offset;
2058	*end_ret = found_end;
2059	goto out;
2060	}
2061	ret = 1;
2062	next:
2063	/* check the next slot in the tree to see if it is a valid item */
2064	nritems = btrfs_header_nritems(eb: path->nodes[0]);
2065	path->slots[0]++;
2066	if (path->slots[0] >= nritems) {
2067	ret = btrfs_next_leaf(root, path);
2068	if (ret)
2069	goto out;
2070	}
2071
2072	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]);
2073
2074	if (key.type != BTRFS_DIR_LOG_INDEX_KEY || key.objectid != dirid) {
2075	ret = 1;
2076	goto out;
2077	}
2078	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
2079	struct btrfs_dir_log_item);
2080	found_end = btrfs_dir_log_end(eb: path->nodes[0], s: item);
2081	*start_ret = key.offset;
2082	*end_ret = found_end;
2083	ret = 0;
2084	out:
2085	btrfs_release_path(p: path);
2086	return ret;
2087	}
2088
2089	/*
2090	* this looks for a given directory item in the log. If the directory
2091	* item is not in the log, the item is removed and the inode it points
2092	* to is unlinked
2093	*/
2094	static noinline int check_item_in_log(struct btrfs_trans_handle *trans,
2095	struct btrfs_root *log,
2096	struct btrfs_path *path,
2097	struct btrfs_path *log_path,
2098	struct inode *dir,
2099	struct btrfs_key *dir_key)
2100	{
2101	struct btrfs_root *root = BTRFS_I(inode: dir)->root;
2102	int ret;
2103	struct extent_buffer *eb;
2104	int slot;
2105	struct btrfs_dir_item *di;
2106	struct fscrypt_str name;
2107	struct inode *inode = NULL;
2108	struct btrfs_key location;
2109
2110	/*
2111	* Currently we only log dir index keys. Even if we replay a log created
2112	* by an older kernel that logged both dir index and dir item keys, all
2113	* we need to do is process the dir index keys, we (and our caller) can
2114	* safely ignore dir item keys (key type BTRFS_DIR_ITEM_KEY).
2115	*/
2116	ASSERT(dir_key->type == BTRFS_DIR_INDEX_KEY);
2117
2118	eb = path->nodes[0];
2119	slot = path->slots[0];
2120	di = btrfs_item_ptr(eb, slot, struct btrfs_dir_item);
2121	ret = read_alloc_one_name(eb, start: di + 1, len: btrfs_dir_name_len(eb, s: di), name: &name);
2122	if (ret)
2123	goto out;
2124
2125	if (log) {
2126	struct btrfs_dir_item *log_di;
2127
2128	log_di = btrfs_lookup_dir_index_item(trans, root: log, path: log_path,
2129	dir: dir_key->objectid,
2130	index: dir_key->offset, name: &name, mod: 0);
2131	if (IS_ERR(ptr: log_di)) {
2132	ret = PTR_ERR(ptr: log_di);
2133	goto out;
2134	} else if (log_di) {
2135	/* The dentry exists in the log, we have nothing to do. */
2136	ret = 0;
2137	goto out;
2138	}
2139	}
2140
2141	btrfs_dir_item_key_to_cpu(eb, item: di, cpu_key: &location);
2142	btrfs_release_path(p: path);
2143	btrfs_release_path(p: log_path);
2144	inode = read_one_inode(root, objectid: location.objectid);
2145	if (!inode) {
2146	ret = -EIO;
2147	goto out;
2148	}
2149
2150	ret = link_to_fixup_dir(trans, root, path, objectid: location.objectid);
2151	if (ret)
2152	goto out;
2153
2154	inc_nlink(inode);
2155	ret = unlink_inode_for_log_replay(trans, dir: BTRFS_I(inode: dir), inode: BTRFS_I(inode),
2156	name: &name);
2157	/*
2158	* Unlike dir item keys, dir index keys can only have one name (entry) in
2159	* them, as there are no key collisions since each key has a unique offset
2160	* (an index number), so we're done.
2161	*/
2162	out:
2163	btrfs_release_path(p: path);
2164	btrfs_release_path(p: log_path);
2165	kfree(objp: name.name);
2166	iput(inode);
2167	return ret;
2168	}
2169
2170	static int replay_xattr_deletes(struct btrfs_trans_handle *trans,
2171	struct btrfs_root *root,
2172	struct btrfs_root *log,
2173	struct btrfs_path *path,
2174	const u64 ino)
2175	{
2176	struct btrfs_key search_key;
2177	struct btrfs_path *log_path;
2178	int i;
2179	int nritems;
2180	int ret;
2181
2182	log_path = btrfs_alloc_path();
2183	if (!log_path)
2184	return -ENOMEM;
2185
2186	search_key.objectid = ino;
2187	search_key.type = BTRFS_XATTR_ITEM_KEY;
2188	search_key.offset = 0;
2189	again:
2190	ret = btrfs_search_slot(NULL, root, key: &search_key, p: path, ins_len: 0, cow: 0);
2191	if (ret < 0)
2192	goto out;
2193	process_leaf:
2194	nritems = btrfs_header_nritems(eb: path->nodes[0]);
2195	for (i = path->slots[0]; i < nritems; i++) {
2196	struct btrfs_key key;
2197	struct btrfs_dir_item *di;
2198	struct btrfs_dir_item *log_di;
2199	u32 total_size;
2200	u32 cur;
2201
2202	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: i);
2203	if (key.objectid != ino || key.type != BTRFS_XATTR_ITEM_KEY) {
2204	ret = 0;
2205	goto out;
2206	}
2207
2208	di = btrfs_item_ptr(path->nodes[0], i, struct btrfs_dir_item);
2209	total_size = btrfs_item_size(eb: path->nodes[0], slot: i);
2210	cur = 0;
2211	while (cur < total_size) {
2212	u16 name_len = btrfs_dir_name_len(eb: path->nodes[0], s: di);
2213	u16 data_len = btrfs_dir_data_len(eb: path->nodes[0], s: di);
2214	u32 this_len = sizeof(*di) + name_len + data_len;
2215	char *name;
2216
2217	name = kmalloc(size: name_len, GFP_NOFS);
2218	if (!name) {
2219	ret = -ENOMEM;
2220	goto out;
2221	}
2222	read_extent_buffer(eb: path->nodes[0], dst: name,
2223	start: (unsigned long)(di + 1), len: name_len);
2224
2225	log_di = btrfs_lookup_xattr(NULL, root: log, path: log_path, dir: ino,
2226	name, name_len, mod: 0);
2227	btrfs_release_path(p: log_path);
2228	if (!log_di) {
2229	/* Doesn't exist in log tree, so delete it. */
2230	btrfs_release_path(p: path);
2231	di = btrfs_lookup_xattr(trans, root, path, dir: ino,
2232	name, name_len, mod: -1);
2233	kfree(objp: name);
2234	if (IS_ERR(ptr: di)) {
2235	ret = PTR_ERR(ptr: di);
2236	goto out;
2237	}
2238	ASSERT(di);
2239	ret = btrfs_delete_one_dir_name(trans, root,
2240	path, di);
2241	if (ret)
2242	goto out;
2243	btrfs_release_path(p: path);
2244	search_key = key;
2245	goto again;
2246	}
2247	kfree(objp: name);
2248	if (IS_ERR(ptr: log_di)) {
2249	ret = PTR_ERR(ptr: log_di);
2250	goto out;
2251	}
2252	cur += this_len;
2253	di = (struct btrfs_dir_item *)((char *)di + this_len);
2254	}
2255	}
2256	ret = btrfs_next_leaf(root, path);
2257	if (ret > 0)
2258	ret = 0;
2259	else if (ret == 0)
2260	goto process_leaf;
2261	out:
2262	btrfs_free_path(p: log_path);
2263	btrfs_release_path(p: path);
2264	return ret;
2265	}
2266
2267
2268	/*
2269	* deletion replay happens before we copy any new directory items
2270	* out of the log or out of backreferences from inodes. It
2271	* scans the log to find ranges of keys that log is authoritative for,
2272	* and then scans the directory to find items in those ranges that are
2273	* not present in the log.
2274	*
2275	* Anything we don't find in the log is unlinked and removed from the
2276	* directory.
2277	*/
2278	static noinline int replay_dir_deletes(struct btrfs_trans_handle *trans,
2279	struct btrfs_root *root,
2280	struct btrfs_root *log,
2281	struct btrfs_path *path,
2282	u64 dirid, int del_all)
2283	{
2284	u64 range_start;
2285	u64 range_end;
2286	int ret = 0;
2287	struct btrfs_key dir_key;
2288	struct btrfs_key found_key;
2289	struct btrfs_path *log_path;
2290	struct inode *dir;
2291
2292	dir_key.objectid = dirid;
2293	dir_key.type = BTRFS_DIR_INDEX_KEY;
2294	log_path = btrfs_alloc_path();
2295	if (!log_path)
2296	return -ENOMEM;
2297
2298	dir = read_one_inode(root, objectid: dirid);
2299	/* it isn't an error if the inode isn't there, that can happen
2300	* because we replay the deletes before we copy in the inode item
2301	* from the log
2302	*/
2303	if (!dir) {
2304	btrfs_free_path(p: log_path);
2305	return 0;
2306	}
2307
2308	range_start = 0;
2309	range_end = 0;
2310	while (1) {
2311	if (del_all)
2312	range_end = (u64)-1;
2313	else {
2314	ret = find_dir_range(root: log, path, dirid,
2315	start_ret: &range_start, end_ret: &range_end);
2316	if (ret < 0)
2317	goto out;
2318	else if (ret > 0)
2319	break;
2320	}
2321
2322	dir_key.offset = range_start;
2323	while (1) {
2324	int nritems;
2325	ret = btrfs_search_slot(NULL, root, key: &dir_key, p: path,
2326	ins_len: 0, cow: 0);
2327	if (ret < 0)
2328	goto out;
2329
2330	nritems = btrfs_header_nritems(eb: path->nodes[0]);
2331	if (path->slots[0] >= nritems) {
2332	ret = btrfs_next_leaf(root, path);
2333	if (ret == 1)
2334	break;
2335	else if (ret < 0)
2336	goto out;
2337	}
2338	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &found_key,
2339	nr: path->slots[0]);
2340	if (found_key.objectid != dirid ||
2341	found_key.type != dir_key.type) {
2342	ret = 0;
2343	goto out;
2344	}
2345
2346	if (found_key.offset > range_end)
2347	break;
2348
2349	ret = check_item_in_log(trans, log, path,
2350	log_path, dir,
2351	dir_key: &found_key);
2352	if (ret)
2353	goto out;
2354	if (found_key.offset == (u64)-1)
2355	break;
2356	dir_key.offset = found_key.offset + 1;
2357	}
2358	btrfs_release_path(p: path);
2359	if (range_end == (u64)-1)
2360	break;
2361	range_start = range_end + 1;
2362	}
2363	ret = 0;
2364	out:
2365	btrfs_release_path(p: path);
2366	btrfs_free_path(p: log_path);
2367	iput(dir);
2368	return ret;
2369	}
2370
2371	/*
2372	* the process_func used to replay items from the log tree. This
2373	* gets called in two different stages. The first stage just looks
2374	* for inodes and makes sure they are all copied into the subvolume.
2375	*
2376	* The second stage copies all the other item types from the log into
2377	* the subvolume. The two stage approach is slower, but gets rid of
2378	* lots of complexity around inodes referencing other inodes that exist
2379	* only in the log (references come from either directory items or inode
2380	* back refs).
2381	*/
2382	static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb,
2383	struct walk_control *wc, u64 gen, int level)
2384	{
2385	int nritems;
2386	struct btrfs_tree_parent_check check = {
2387	.transid = gen,
2388	.level = level
2389	};
2390	struct btrfs_path *path;
2391	struct btrfs_root *root = wc->replay_dest;
2392	struct btrfs_key key;
2393	int i;
2394	int ret;
2395
2396	ret = btrfs_read_extent_buffer(buf: eb, check: &check);
2397	if (ret)
2398	return ret;
2399
2400	level = btrfs_header_level(eb);
2401
2402	if (level != 0)
2403	return 0;
2404
2405	path = btrfs_alloc_path();
2406	if (!path)
2407	return -ENOMEM;
2408
2409	nritems = btrfs_header_nritems(eb);
2410	for (i = 0; i < nritems; i++) {
2411	btrfs_item_key_to_cpu(eb, cpu_key: &key, nr: i);
2412
2413	/* inode keys are done during the first stage */
2414	if (key.type == BTRFS_INODE_ITEM_KEY &&
2415	wc->stage == LOG_WALK_REPLAY_INODES) {
2416	struct btrfs_inode_item *inode_item;
2417	u32 mode;
2418
2419	inode_item = btrfs_item_ptr(eb, i,
2420	struct btrfs_inode_item);
2421	/*
2422	* If we have a tmpfile (O_TMPFILE) that got fsync'ed
2423	* and never got linked before the fsync, skip it, as
2424	* replaying it is pointless since it would be deleted
2425	* later. We skip logging tmpfiles, but it's always
2426	* possible we are replaying a log created with a kernel
2427	* that used to log tmpfiles.
2428	*/
2429	if (btrfs_inode_nlink(eb, s: inode_item) == 0) {
2430	wc->ignore_cur_inode = true;
2431	continue;
2432	} else {
2433	wc->ignore_cur_inode = false;
2434	}
2435	ret = replay_xattr_deletes(trans: wc->trans, root, log,
2436	path, ino: key.objectid);
2437	if (ret)
2438	break;
2439	mode = btrfs_inode_mode(eb, s: inode_item);
2440	if (S_ISDIR(mode)) {
2441	ret = replay_dir_deletes(trans: wc->trans,
2442	root, log, path, dirid: key.objectid, del_all: 0);
2443	if (ret)
2444	break;
2445	}
2446	ret = overwrite_item(trans: wc->trans, root, path,
2447	eb, slot: i, key: &key);
2448	if (ret)
2449	break;
2450
2451	/*
2452	* Before replaying extents, truncate the inode to its
2453	* size. We need to do it now and not after log replay
2454	* because before an fsync we can have prealloc extents
2455	* added beyond the inode's i_size. If we did it after,
2456	* through orphan cleanup for example, we would drop
2457	* those prealloc extents just after replaying them.
2458	*/
2459	if (S_ISREG(mode)) {
2460	struct btrfs_drop_extents_args drop_args = { 0 };
2461	struct inode *inode;
2462	u64 from;
2463
2464	inode = read_one_inode(root, objectid: key.objectid);
2465	if (!inode) {
2466	ret = -EIO;
2467	break;
2468	}
2469	from = ALIGN(i_size_read(inode),
2470	root->fs_info->sectorsize);
2471	drop_args.start = from;
2472	drop_args.end = (u64)-1;
2473	drop_args.drop_cache = true;
2474	ret = btrfs_drop_extents(trans: wc->trans, root,
2475	inode: BTRFS_I(inode),
2476	args: &drop_args);
2477	if (!ret) {
2478	inode_sub_bytes(inode,
2479	bytes: drop_args.bytes_found);
2480	/* Update the inode's nbytes. */
2481	ret = btrfs_update_inode(trans: wc->trans,
2482	inode: BTRFS_I(inode));
2483	}
2484	iput(inode);
2485	if (ret)
2486	break;
2487	}
2488
2489	ret = link_to_fixup_dir(trans: wc->trans, root,
2490	path, objectid: key.objectid);
2491	if (ret)
2492	break;
2493	}
2494
2495	if (wc->ignore_cur_inode)
2496	continue;
2497
2498	if (key.type == BTRFS_DIR_INDEX_KEY &&
2499	wc->stage == LOG_WALK_REPLAY_DIR_INDEX) {
2500	ret = replay_one_dir_item(trans: wc->trans, root, path,
2501	eb, slot: i, key: &key);
2502	if (ret)
2503	break;
2504	}
2505
2506	if (wc->stage < LOG_WALK_REPLAY_ALL)
2507	continue;
2508
2509	/* these keys are simply copied */
2510	if (key.type == BTRFS_XATTR_ITEM_KEY) {
2511	ret = overwrite_item(trans: wc->trans, root, path,
2512	eb, slot: i, key: &key);
2513	if (ret)
2514	break;
2515	} else if (key.type == BTRFS_INODE_REF_KEY ||
2516	key.type == BTRFS_INODE_EXTREF_KEY) {
2517	ret = add_inode_ref(trans: wc->trans, root, log, path,
2518	eb, slot: i, key: &key);
2519	if (ret && ret != -ENOENT)
2520	break;
2521	ret = 0;
2522	} else if (key.type == BTRFS_EXTENT_DATA_KEY) {
2523	ret = replay_one_extent(trans: wc->trans, root, path,
2524	eb, slot: i, key: &key);
2525	if (ret)
2526	break;
2527	}
2528	/*
2529	* We don't log BTRFS_DIR_ITEM_KEY keys anymore, only the
2530	* BTRFS_DIR_INDEX_KEY items which we use to derive the
2531	* BTRFS_DIR_ITEM_KEY items. If we are replaying a log from an
2532	* older kernel with such keys, ignore them.
2533	*/
2534	}
2535	btrfs_free_path(p: path);
2536	return ret;
2537	}
2538
2539	/*
2540	* Correctly adjust the reserved bytes occupied by a log tree extent buffer
2541	*/
2542	static void unaccount_log_buffer(struct btrfs_fs_info *fs_info, u64 start)
2543	{
2544	struct btrfs_block_group *cache;
2545
2546	cache = btrfs_lookup_block_group(info: fs_info, bytenr: start);
2547	if (!cache) {
2548	btrfs_err(fs_info, "unable to find block group for %llu", start);
2549	return;
2550	}
2551
2552	spin_lock(lock: &cache->space_info->lock);
2553	spin_lock(lock: &cache->lock);
2554	cache->reserved -= fs_info->nodesize;
2555	cache->space_info->bytes_reserved -= fs_info->nodesize;
2556	spin_unlock(lock: &cache->lock);
2557	spin_unlock(lock: &cache->space_info->lock);
2558
2559	btrfs_put_block_group(cache);
2560	}
2561
2562	static int clean_log_buffer(struct btrfs_trans_handle *trans,
2563	struct extent_buffer *eb)
2564	{
2565	int ret;
2566
2567	btrfs_tree_lock(eb);
2568	btrfs_clear_buffer_dirty(trans, buf: eb);
2569	wait_on_extent_buffer_writeback(eb);
2570	btrfs_tree_unlock(eb);
2571
2572	if (trans) {
2573	ret = btrfs_pin_reserved_extent(trans, eb);
2574	if (ret)
2575	return ret;
2576	} else {
2577	unaccount_log_buffer(fs_info: eb->fs_info, start: eb->start);
2578	}
2579
2580	return 0;
2581	}
2582
2583	static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
2584	struct btrfs_root *root,
2585	struct btrfs_path *path, int *level,
2586	struct walk_control *wc)
2587	{
2588	struct btrfs_fs_info *fs_info = root->fs_info;
2589	u64 bytenr;
2590	u64 ptr_gen;
2591	struct extent_buffer *next;
2592	struct extent_buffer *cur;
2593	int ret = 0;
2594
2595	while (*level > 0) {
2596	struct btrfs_tree_parent_check check = { 0 };
2597
2598	cur = path->nodes[*level];
2599
2600	WARN_ON(btrfs_header_level(cur) != *level);
2601
2602	if (path->slots[*level] >=
2603	btrfs_header_nritems(eb: cur))
2604	break;
2605
2606	bytenr = btrfs_node_blockptr(eb: cur, nr: path->slots[*level]);
2607	ptr_gen = btrfs_node_ptr_generation(eb: cur, nr: path->slots[*level]);
2608	check.transid = ptr_gen;
2609	check.level = *level - 1;
2610	check.has_first_key = true;
2611	btrfs_node_key_to_cpu(eb: cur, cpu_key: &check.first_key, nr: path->slots[*level]);
2612
2613	next = btrfs_find_create_tree_block(fs_info, bytenr,
2614	owner_root: btrfs_header_owner(eb: cur),
2615	level: *level - 1);
2616	if (IS_ERR(ptr: next))
2617	return PTR_ERR(ptr: next);
2618
2619	if (*level == 1) {
2620	ret = wc->process_func(root, next, wc, ptr_gen,
2621	*level - 1);
2622	if (ret) {
2623	free_extent_buffer(eb: next);
2624	return ret;
2625	}
2626
2627	path->slots[*level]++;
2628	if (wc->free) {
2629	ret = btrfs_read_extent_buffer(buf: next, check: &check);
2630	if (ret) {
2631	free_extent_buffer(eb: next);
2632	return ret;
2633	}
2634
2635	ret = clean_log_buffer(trans, eb: next);
2636	if (ret) {
2637	free_extent_buffer(eb: next);
2638	return ret;
2639	}
2640	}
2641	free_extent_buffer(eb: next);
2642	continue;
2643	}
2644	ret = btrfs_read_extent_buffer(buf: next, check: &check);
2645	if (ret) {
2646	free_extent_buffer(eb: next);
2647	return ret;
2648	}
2649
2650	if (path->nodes[*level-1])
2651	free_extent_buffer(eb: path->nodes[*level-1]);
2652	path->nodes[*level-1] = next;
2653	*level = btrfs_header_level(eb: next);
2654	path->slots[*level] = 0;
2655	cond_resched();
2656	}
2657	path->slots[*level] = btrfs_header_nritems(eb: path->nodes[*level]);
2658
2659	cond_resched();
2660	return 0;
2661	}
2662
2663	static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
2664	struct btrfs_root *root,
2665	struct btrfs_path *path, int *level,
2666	struct walk_control *wc)
2667	{
2668	int i;
2669	int slot;
2670	int ret;
2671
2672	for (i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
2673	slot = path->slots[i];
2674	if (slot + 1 < btrfs_header_nritems(eb: path->nodes[i])) {
2675	path->slots[i]++;
2676	*level = i;
2677	WARN_ON(*level == 0);
2678	return 0;
2679	} else {
2680	ret = wc->process_func(root, path->nodes[*level], wc,
2681	btrfs_header_generation(eb: path->nodes[*level]),
2682	*level);
2683	if (ret)
2684	return ret;
2685
2686	if (wc->free) {
2687	ret = clean_log_buffer(trans, eb: path->nodes[*level]);
2688	if (ret)
2689	return ret;
2690	}
2691	free_extent_buffer(eb: path->nodes[*level]);
2692	path->nodes[*level] = NULL;
2693	*level = i + 1;
2694	}
2695	}
2696	return 1;
2697	}
2698
2699	/*
2700	* drop the reference count on the tree rooted at 'snap'. This traverses
2701	* the tree freeing any blocks that have a ref count of zero after being
2702	* decremented.
2703	*/
2704	static int walk_log_tree(struct btrfs_trans_handle *trans,
2705	struct btrfs_root *log, struct walk_control *wc)
2706	{
2707	int ret = 0;
2708	int wret;
2709	int level;
2710	struct btrfs_path *path;
2711	int orig_level;
2712
2713	path = btrfs_alloc_path();
2714	if (!path)
2715	return -ENOMEM;
2716
2717	level = btrfs_header_level(eb: log->node);
2718	orig_level = level;
2719	path->nodes[level] = log->node;
2720	atomic_inc(v: &log->node->refs);
2721	path->slots[level] = 0;
2722
2723	while (1) {
2724	wret = walk_down_log_tree(trans, root: log, path, level: &level, wc);
2725	if (wret > 0)
2726	break;
2727	if (wret < 0) {
2728	ret = wret;
2729	goto out;
2730	}
2731
2732	wret = walk_up_log_tree(trans, root: log, path, level: &level, wc);
2733	if (wret > 0)
2734	break;
2735	if (wret < 0) {
2736	ret = wret;
2737	goto out;
2738	}
2739	}
2740
2741	/* was the root node processed? if not, catch it here */
2742	if (path->nodes[orig_level]) {
2743	ret = wc->process_func(log, path->nodes[orig_level], wc,
2744	btrfs_header_generation(eb: path->nodes[orig_level]),
2745	orig_level);
2746	if (ret)
2747	goto out;
2748	if (wc->free)
2749	ret = clean_log_buffer(trans, eb: path->nodes[orig_level]);
2750	}
2751
2752	out:
2753	btrfs_free_path(p: path);
2754	return ret;
2755	}
2756
2757	/*
2758	* helper function to update the item for a given subvolumes log root
2759	* in the tree of log roots
2760	*/
2761	static int update_log_root(struct btrfs_trans_handle *trans,
2762	struct btrfs_root *log,
2763	struct btrfs_root_item *root_item)
2764	{
2765	struct btrfs_fs_info *fs_info = log->fs_info;
2766	int ret;
2767
2768	if (log->log_transid == 1) {
2769	/* insert root item on the first sync */
2770	ret = btrfs_insert_root(trans, root: fs_info->log_root_tree,
2771	key: &log->root_key, item: root_item);
2772	} else {
2773	ret = btrfs_update_root(trans, root: fs_info->log_root_tree,
2774	key: &log->root_key, item: root_item);
2775	}
2776	return ret;
2777	}
2778
2779	static void wait_log_commit(struct btrfs_root *root, int transid)
2780	{
2781	DEFINE_WAIT(wait);
2782	int index = transid % 2;
2783
2784	/*
2785	* we only allow two pending log transactions at a time,
2786	* so we know that if ours is more than 2 older than the
2787	* current transaction, we're done
2788	*/
2789	for (;;) {
2790	prepare_to_wait(wq_head: &root->log_commit_wait[index],
2791	wq_entry: &wait, TASK_UNINTERRUPTIBLE);
2792
2793	if (!(root->log_transid_committed < transid &&
2794	atomic_read(v: &root->log_commit[index])))
2795	break;
2796
2797	mutex_unlock(lock: &root->log_mutex);
2798	schedule();
2799	mutex_lock(&root->log_mutex);
2800	}
2801	finish_wait(wq_head: &root->log_commit_wait[index], wq_entry: &wait);
2802	}
2803
2804	static void wait_for_writer(struct btrfs_root *root)
2805	{
2806	DEFINE_WAIT(wait);
2807
2808	for (;;) {
2809	prepare_to_wait(wq_head: &root->log_writer_wait, wq_entry: &wait,
2810	TASK_UNINTERRUPTIBLE);
2811	if (!atomic_read(v: &root->log_writers))
2812	break;
2813
2814	mutex_unlock(lock: &root->log_mutex);
2815	schedule();
2816	mutex_lock(&root->log_mutex);
2817	}
2818	finish_wait(wq_head: &root->log_writer_wait, wq_entry: &wait);
2819	}
2820
2821	void btrfs_init_log_ctx(struct btrfs_log_ctx *ctx, struct inode *inode)
2822	{
2823	ctx->log_ret = 0;
2824	ctx->log_transid = 0;
2825	ctx->log_new_dentries = false;
2826	ctx->logging_new_name = false;
2827	ctx->logging_new_delayed_dentries = false;
2828	ctx->logged_before = false;
2829	ctx->inode = inode;
2830	INIT_LIST_HEAD(list: &ctx->list);
2831	INIT_LIST_HEAD(list: &ctx->ordered_extents);
2832	INIT_LIST_HEAD(list: &ctx->conflict_inodes);
2833	ctx->num_conflict_inodes = 0;
2834	ctx->logging_conflict_inodes = false;
2835	ctx->scratch_eb = NULL;
2836	}
2837
2838	void btrfs_init_log_ctx_scratch_eb(struct btrfs_log_ctx *ctx)
2839	{
2840	struct btrfs_inode *inode = BTRFS_I(inode: ctx->inode);
2841
2842	if (!test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &inode->runtime_flags) &&
2843	!test_bit(BTRFS_INODE_COPY_EVERYTHING, &inode->runtime_flags))
2844	return;
2845
2846	/*
2847	* Don't care about allocation failure. This is just for optimization,
2848	* if we fail to allocate here, we will try again later if needed.
2849	*/
2850	ctx->scratch_eb = alloc_dummy_extent_buffer(fs_info: inode->root->fs_info, start: 0);
2851	}
2852
2853	void btrfs_release_log_ctx_extents(struct btrfs_log_ctx *ctx)
2854	{
2855	struct btrfs_ordered_extent *ordered;
2856	struct btrfs_ordered_extent *tmp;
2857
2858	ASSERT(inode_is_locked(ctx->inode));
2859
2860	list_for_each_entry_safe(ordered, tmp, &ctx->ordered_extents, log_list) {
2861	list_del_init(entry: &ordered->log_list);
2862	btrfs_put_ordered_extent(entry: ordered);
2863	}
2864	}
2865
2866
2867	static inline void btrfs_remove_log_ctx(struct btrfs_root *root,
2868	struct btrfs_log_ctx *ctx)
2869	{
2870	mutex_lock(&root->log_mutex);
2871	list_del_init(entry: &ctx->list);
2872	mutex_unlock(lock: &root->log_mutex);
2873	}
2874
2875	/*
2876	* Invoked in log mutex context, or be sure there is no other task which
2877	* can access the list.
2878	*/
2879	static inline void btrfs_remove_all_log_ctxs(struct btrfs_root *root,
2880	int index, int error)
2881	{
2882	struct btrfs_log_ctx *ctx;
2883	struct btrfs_log_ctx *safe;
2884
2885	list_for_each_entry_safe(ctx, safe, &root->log_ctxs[index], list) {
2886	list_del_init(entry: &ctx->list);
2887	ctx->log_ret = error;
2888	}
2889	}
2890
2891	/*
2892	* Sends a given tree log down to the disk and updates the super blocks to
2893	* record it. When this call is done, you know that any inodes previously
2894	* logged are safely on disk only if it returns 0.
2895	*
2896	* Any other return value means you need to call btrfs_commit_transaction.
2897	* Some of the edge cases for fsyncing directories that have had unlinks
2898	* or renames done in the past mean that sometimes the only safe
2899	* fsync is to commit the whole FS. When btrfs_sync_log returns -EAGAIN,
2900	* that has happened.
2901	*/
2902	int btrfs_sync_log(struct btrfs_trans_handle *trans,
2903	struct btrfs_root *root, struct btrfs_log_ctx *ctx)
2904	{
2905	int index1;
2906	int index2;
2907	int mark;
2908	int ret;
2909	struct btrfs_fs_info *fs_info = root->fs_info;
2910	struct btrfs_root *log = root->log_root;
2911	struct btrfs_root *log_root_tree = fs_info->log_root_tree;
2912	struct btrfs_root_item new_root_item;
2913	int log_transid = 0;
2914	struct btrfs_log_ctx root_log_ctx;
2915	struct blk_plug plug;
2916	u64 log_root_start;
2917	u64 log_root_level;
2918
2919	mutex_lock(&root->log_mutex);
2920	log_transid = ctx->log_transid;
2921	if (root->log_transid_committed >= log_transid) {
2922	mutex_unlock(lock: &root->log_mutex);
2923	return ctx->log_ret;
2924	}
2925
2926	index1 = log_transid % 2;
2927	if (atomic_read(v: &root->log_commit[index1])) {
2928	wait_log_commit(root, transid: log_transid);
2929	mutex_unlock(lock: &root->log_mutex);
2930	return ctx->log_ret;
2931	}
2932	ASSERT(log_transid == root->log_transid);
2933	atomic_set(v: &root->log_commit[index1], i: 1);
2934
2935	/* wait for previous tree log sync to complete */
2936	if (atomic_read(v: &root->log_commit[(index1 + 1) % 2]))
2937	wait_log_commit(root, transid: log_transid - 1);
2938
2939	while (1) {
2940	int batch = atomic_read(v: &root->log_batch);
2941	/* when we're on an ssd, just kick the log commit out */
2942	if (!btrfs_test_opt(fs_info, SSD) &&
2943	test_bit(BTRFS_ROOT_MULTI_LOG_TASKS, &root->state)) {
2944	mutex_unlock(lock: &root->log_mutex);
2945	schedule_timeout_uninterruptible(timeout: 1);
2946	mutex_lock(&root->log_mutex);
2947	}
2948	wait_for_writer(root);
2949	if (batch == atomic_read(v: &root->log_batch))
2950	break;
2951	}
2952
2953	/* bail out if we need to do a full commit */
2954	if (btrfs_need_log_full_commit(trans)) {
2955	ret = BTRFS_LOG_FORCE_COMMIT;
2956	mutex_unlock(lock: &root->log_mutex);
2957	goto out;
2958	}
2959
2960	if (log_transid % 2 == 0)
2961	mark = EXTENT_DIRTY;
2962	else
2963	mark = EXTENT_NEW;
2964
2965	/* we start IO on all the marked extents here, but we don't actually
2966	* wait for them until later.
2967	*/
2968	blk_start_plug(&plug);
2969	ret = btrfs_write_marked_extents(fs_info, dirty_pages: &log->dirty_log_pages, mark);
2970	/*
2971	* -EAGAIN happens when someone, e.g., a concurrent transaction
2972	* commit, writes a dirty extent in this tree-log commit. This
2973	* concurrent write will create a hole writing out the extents,
2974	* and we cannot proceed on a zoned filesystem, requiring
2975	* sequential writing. While we can bail out to a full commit
2976	* here, but we can continue hoping the concurrent writing fills
2977	* the hole.
2978	*/
2979	if (ret == -EAGAIN && btrfs_is_zoned(fs_info))
2980	ret = 0;
2981	if (ret) {
2982	blk_finish_plug(&plug);
2983	btrfs_set_log_full_commit(trans);
2984	mutex_unlock(lock: &root->log_mutex);
2985	goto out;
2986	}
2987
2988	/*
2989	* We _must_ update under the root->log_mutex in order to make sure we
2990	* have a consistent view of the log root we are trying to commit at
2991	* this moment.
2992	*
2993	* We _must_ copy this into a local copy, because we are not holding the
2994	* log_root_tree->log_mutex yet. This is important because when we
2995	* commit the log_root_tree we must have a consistent view of the
2996	* log_root_tree when we update the super block to point at the
2997	* log_root_tree bytenr. If we update the log_root_tree here we'll race
2998	* with the commit and possibly point at the new block which we may not
2999	* have written out.
3000	*/
3001	btrfs_set_root_node(item: &log->root_item, node: log->node);
3002	memcpy(&new_root_item, &log->root_item, sizeof(new_root_item));
3003
3004	btrfs_set_root_log_transid(root, log_transid: root->log_transid + 1);
3005	log->log_transid = root->log_transid;
3006	root->log_start_pid = 0;
3007	/*
3008	* IO has been started, blocks of the log tree have WRITTEN flag set
3009	* in their headers. new modifications of the log will be written to
3010	* new positions. so it's safe to allow log writers to go in.
3011	*/
3012	mutex_unlock(lock: &root->log_mutex);
3013
3014	if (btrfs_is_zoned(fs_info)) {
3015	mutex_lock(&fs_info->tree_root->log_mutex);
3016	if (!log_root_tree->node) {
3017	ret = btrfs_alloc_log_tree_node(trans, root: log_root_tree);
3018	if (ret) {
3019	mutex_unlock(lock: &fs_info->tree_root->log_mutex);
3020	blk_finish_plug(&plug);
3021	goto out;
3022	}
3023	}
3024	mutex_unlock(lock: &fs_info->tree_root->log_mutex);
3025	}
3026
3027	btrfs_init_log_ctx(ctx: &root_log_ctx, NULL);
3028
3029	mutex_lock(&log_root_tree->log_mutex);
3030
3031	index2 = log_root_tree->log_transid % 2;
3032	list_add_tail(new: &root_log_ctx.list, head: &log_root_tree->log_ctxs[index2]);
3033	root_log_ctx.log_transid = log_root_tree->log_transid;
3034
3035	/*
3036	* Now we are safe to update the log_root_tree because we're under the
3037	* log_mutex, and we're a current writer so we're holding the commit
3038	* open until we drop the log_mutex.
3039	*/
3040	ret = update_log_root(trans, log, root_item: &new_root_item);
3041	if (ret) {
3042	list_del_init(entry: &root_log_ctx.list);
3043	blk_finish_plug(&plug);
3044	btrfs_set_log_full_commit(trans);
3045	if (ret != -ENOSPC)
3046	btrfs_err(fs_info,
3047	"failed to update log for root %llu ret %d",
3048	root->root_key.objectid, ret);
3049	btrfs_wait_tree_log_extents(root: log, mark);
3050	mutex_unlock(lock: &log_root_tree->log_mutex);
3051	goto out;
3052	}
3053
3054	if (log_root_tree->log_transid_committed >= root_log_ctx.log_transid) {
3055	blk_finish_plug(&plug);
3056	list_del_init(entry: &root_log_ctx.list);
3057	mutex_unlock(lock: &log_root_tree->log_mutex);
3058	ret = root_log_ctx.log_ret;
3059	goto out;
3060	}
3061
3062	if (atomic_read(v: &log_root_tree->log_commit[index2])) {
3063	blk_finish_plug(&plug);
3064	ret = btrfs_wait_tree_log_extents(root: log, mark);
3065	wait_log_commit(root: log_root_tree,
3066	transid: root_log_ctx.log_transid);
3067	mutex_unlock(lock: &log_root_tree->log_mutex);
3068	if (!ret)
3069	ret = root_log_ctx.log_ret;
3070	goto out;
3071	}
3072	ASSERT(root_log_ctx.log_transid == log_root_tree->log_transid);
3073	atomic_set(v: &log_root_tree->log_commit[index2], i: 1);
3074
3075	if (atomic_read(v: &log_root_tree->log_commit[(index2 + 1) % 2])) {
3076	wait_log_commit(root: log_root_tree,
3077	transid: root_log_ctx.log_transid - 1);
3078	}
3079
3080	/*
3081	* now that we've moved on to the tree of log tree roots,
3082	* check the full commit flag again
3083	*/
3084	if (btrfs_need_log_full_commit(trans)) {
3085	blk_finish_plug(&plug);
3086	btrfs_wait_tree_log_extents(root: log, mark);
3087	mutex_unlock(lock: &log_root_tree->log_mutex);
3088	ret = BTRFS_LOG_FORCE_COMMIT;
3089	goto out_wake_log_root;
3090	}
3091
3092	ret = btrfs_write_marked_extents(fs_info,
3093	dirty_pages: &log_root_tree->dirty_log_pages,
3094	mark: EXTENT_DIRTY | EXTENT_NEW);
3095	blk_finish_plug(&plug);
3096	/*
3097	* As described above, -EAGAIN indicates a hole in the extents. We
3098	* cannot wait for these write outs since the waiting cause a
3099	* deadlock. Bail out to the full commit instead.
3100	*/
3101	if (ret == -EAGAIN && btrfs_is_zoned(fs_info)) {
3102	btrfs_set_log_full_commit(trans);
3103	btrfs_wait_tree_log_extents(root: log, mark);
3104	mutex_unlock(lock: &log_root_tree->log_mutex);
3105	goto out_wake_log_root;
3106	} else if (ret) {
3107	btrfs_set_log_full_commit(trans);
3108	mutex_unlock(lock: &log_root_tree->log_mutex);
3109	goto out_wake_log_root;
3110	}
3111	ret = btrfs_wait_tree_log_extents(root: log, mark);
3112	if (!ret)
3113	ret = btrfs_wait_tree_log_extents(root: log_root_tree,
3114	mark: EXTENT_NEW | EXTENT_DIRTY);
3115	if (ret) {
3116	btrfs_set_log_full_commit(trans);
3117	mutex_unlock(lock: &log_root_tree->log_mutex);
3118	goto out_wake_log_root;
3119	}
3120
3121	log_root_start = log_root_tree->node->start;
3122	log_root_level = btrfs_header_level(eb: log_root_tree->node);
3123	log_root_tree->log_transid++;
3124	mutex_unlock(lock: &log_root_tree->log_mutex);
3125
3126	/*
3127	* Here we are guaranteed that nobody is going to write the superblock
3128	* for the current transaction before us and that neither we do write
3129	* our superblock before the previous transaction finishes its commit
3130	* and writes its superblock, because:
3131	*
3132	* 1) We are holding a handle on the current transaction, so no body
3133	* can commit it until we release the handle;
3134	*
3135	* 2) Before writing our superblock we acquire the tree_log_mutex, so
3136	* if the previous transaction is still committing, and hasn't yet
3137	* written its superblock, we wait for it to do it, because a
3138	* transaction commit acquires the tree_log_mutex when the commit
3139	* begins and releases it only after writing its superblock.
3140	*/
3141	mutex_lock(&fs_info->tree_log_mutex);
3142
3143	/*
3144	* The previous transaction writeout phase could have failed, and thus
3145	* marked the fs in an error state. We must not commit here, as we
3146	* could have updated our generation in the super_for_commit and
3147	* writing the super here would result in transid mismatches. If there
3148	* is an error here just bail.
3149	*/
3150	if (BTRFS_FS_ERROR(fs_info)) {
3151	ret = -EIO;
3152	btrfs_set_log_full_commit(trans);
3153	btrfs_abort_transaction(trans, ret);
3154	mutex_unlock(lock: &fs_info->tree_log_mutex);
3155	goto out_wake_log_root;
3156	}
3157
3158	btrfs_set_super_log_root(s: fs_info->super_for_commit, val: log_root_start);
3159	btrfs_set_super_log_root_level(s: fs_info->super_for_commit, val: log_root_level);
3160	ret = write_all_supers(fs_info, max_mirrors: 1);
3161	mutex_unlock(lock: &fs_info->tree_log_mutex);
3162	if (ret) {
3163	btrfs_set_log_full_commit(trans);
3164	btrfs_abort_transaction(trans, ret);
3165	goto out_wake_log_root;
3166	}
3167
3168	/*
3169	* We know there can only be one task here, since we have not yet set
3170	* root->log_commit[index1] to 0 and any task attempting to sync the
3171	* log must wait for the previous log transaction to commit if it's
3172	* still in progress or wait for the current log transaction commit if
3173	* someone else already started it. We use <= and not < because the
3174	* first log transaction has an ID of 0.
3175	*/
3176	ASSERT(btrfs_get_root_last_log_commit(root) <= log_transid);
3177	btrfs_set_root_last_log_commit(root, commit_id: log_transid);
3178
3179	out_wake_log_root:
3180	mutex_lock(&log_root_tree->log_mutex);
3181	btrfs_remove_all_log_ctxs(root: log_root_tree, index: index2, error: ret);
3182
3183	log_root_tree->log_transid_committed++;
3184	atomic_set(v: &log_root_tree->log_commit[index2], i: 0);
3185	mutex_unlock(lock: &log_root_tree->log_mutex);
3186
3187	/*
3188	* The barrier before waitqueue_active (in cond_wake_up) is needed so
3189	* all the updates above are seen by the woken threads. It might not be
3190	* necessary, but proving that seems to be hard.
3191	*/
3192	cond_wake_up(wq: &log_root_tree->log_commit_wait[index2]);
3193	out:
3194	mutex_lock(&root->log_mutex);
3195	btrfs_remove_all_log_ctxs(root, index: index1, error: ret);
3196	root->log_transid_committed++;
3197	atomic_set(v: &root->log_commit[index1], i: 0);
3198	mutex_unlock(lock: &root->log_mutex);
3199
3200	/*
3201	* The barrier before waitqueue_active (in cond_wake_up) is needed so
3202	* all the updates above are seen by the woken threads. It might not be
3203	* necessary, but proving that seems to be hard.
3204	*/
3205	cond_wake_up(wq: &root->log_commit_wait[index1]);
3206	return ret;
3207	}
3208
3209	static void free_log_tree(struct btrfs_trans_handle *trans,
3210	struct btrfs_root *log)
3211	{
3212	int ret;
3213	struct walk_control wc = {
3214	.free = 1,
3215	.process_func = process_one_buffer
3216	};
3217
3218	if (log->node) {
3219	ret = walk_log_tree(trans, log, wc: &wc);
3220	if (ret) {
3221	/*
3222	* We weren't able to traverse the entire log tree, the
3223	* typical scenario is getting an -EIO when reading an
3224	* extent buffer of the tree, due to a previous writeback
3225	* failure of it.
3226	*/
3227	set_bit(nr: BTRFS_FS_STATE_LOG_CLEANUP_ERROR,
3228	addr: &log->fs_info->fs_state);
3229
3230	/*
3231	* Some extent buffers of the log tree may still be dirty
3232	* and not yet written back to storage, because we may
3233	* have updates to a log tree without syncing a log tree,
3234	* such as during rename and link operations. So flush
3235	* them out and wait for their writeback to complete, so
3236	* that we properly cleanup their state and pages.
3237	*/
3238	btrfs_write_marked_extents(fs_info: log->fs_info,
3239	dirty_pages: &log->dirty_log_pages,
3240	mark: EXTENT_DIRTY | EXTENT_NEW);
3241	btrfs_wait_tree_log_extents(root: log,
3242	mark: EXTENT_DIRTY | EXTENT_NEW);
3243
3244	if (trans)
3245	btrfs_abort_transaction(trans, ret);
3246	else
3247	btrfs_handle_fs_error(log->fs_info, ret, NULL);
3248	}
3249	}
3250
3251	extent_io_tree_release(tree: &log->dirty_log_pages);
3252	extent_io_tree_release(tree: &log->log_csum_range);
3253
3254	btrfs_put_root(root: log);
3255	}
3256
3257	/*
3258	* free all the extents used by the tree log. This should be called
3259	* at commit time of the full transaction
3260	*/
3261	int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root)
3262	{
3263	if (root->log_root) {
3264	free_log_tree(trans, log: root->log_root);
3265	root->log_root = NULL;
3266	clear_bit(nr: BTRFS_ROOT_HAS_LOG_TREE, addr: &root->state);
3267	}
3268	return 0;
3269	}
3270
3271	int btrfs_free_log_root_tree(struct btrfs_trans_handle *trans,
3272	struct btrfs_fs_info *fs_info)
3273	{
3274	if (fs_info->log_root_tree) {
3275	free_log_tree(trans, log: fs_info->log_root_tree);
3276	fs_info->log_root_tree = NULL;
3277	clear_bit(nr: BTRFS_ROOT_HAS_LOG_TREE, addr: &fs_info->tree_root->state);
3278	}
3279	return 0;
3280	}
3281
3282	/*
3283	* Check if an inode was logged in the current transaction. This correctly deals
3284	* with the case where the inode was logged but has a logged_trans of 0, which
3285	* happens if the inode is evicted and loaded again, as logged_trans is an in
3286	* memory only field (not persisted).
3287	*
3288	* Returns 1 if the inode was logged before in the transaction, 0 if it was not,
3289	* and < 0 on error.
3290	*/
3291	static int inode_logged(const struct btrfs_trans_handle *trans,
3292	struct btrfs_inode *inode,
3293	struct btrfs_path *path_in)
3294	{
3295	struct btrfs_path *path = path_in;
3296	struct btrfs_key key;
3297	int ret;
3298
3299	if (inode->logged_trans == trans->transid)
3300	return 1;
3301
3302	/*
3303	* If logged_trans is not 0, then we know the inode logged was not logged
3304	* in this transaction, so we can return false right away.
3305	*/
3306	if (inode->logged_trans > 0)
3307	return 0;
3308
3309	/*
3310	* If no log tree was created for this root in this transaction, then
3311	* the inode can not have been logged in this transaction. In that case
3312	* set logged_trans to anything greater than 0 and less than the current
3313	* transaction's ID, to avoid the search below in a future call in case
3314	* a log tree gets created after this.
3315	*/
3316	if (!test_bit(BTRFS_ROOT_HAS_LOG_TREE, &inode->root->state)) {
3317	inode->logged_trans = trans->transid - 1;
3318	return 0;
3319	}
3320
3321	/*
3322	* We have a log tree and the inode's logged_trans is 0. We can't tell
3323	* for sure if the inode was logged before in this transaction by looking
3324	* only at logged_trans. We could be pessimistic and assume it was, but
3325	* that can lead to unnecessarily logging an inode during rename and link
3326	* operations, and then further updating the log in followup rename and
3327	* link operations, specially if it's a directory, which adds latency
3328	* visible to applications doing a series of rename or link operations.
3329	*
3330	* A logged_trans of 0 here can mean several things:
3331	*
3332	* 1) The inode was never logged since the filesystem was mounted, and may
3333	* or may have not been evicted and loaded again;
3334	*
3335	* 2) The inode was logged in a previous transaction, then evicted and
3336	* then loaded again;
3337	*
3338	* 3) The inode was logged in the current transaction, then evicted and
3339	* then loaded again.
3340	*
3341	* For cases 1) and 2) we don't want to return true, but we need to detect
3342	* case 3) and return true. So we do a search in the log root for the inode
3343	* item.
3344	*/
3345	key.objectid = btrfs_ino(inode);
3346	key.type = BTRFS_INODE_ITEM_KEY;
3347	key.offset = 0;
3348
3349	if (!path) {
3350	path = btrfs_alloc_path();
3351	if (!path)
3352	return -ENOMEM;
3353	}
3354
3355	ret = btrfs_search_slot(NULL, root: inode->root->log_root, key: &key, p: path, ins_len: 0, cow: 0);
3356
3357	if (path_in)
3358	btrfs_release_path(p: path);
3359	else
3360	btrfs_free_path(p: path);
3361
3362	/*
3363	* Logging an inode always results in logging its inode item. So if we
3364	* did not find the item we know the inode was not logged for sure.
3365	*/
3366	if (ret < 0) {
3367	return ret;
3368	} else if (ret > 0) {
3369	/*
3370	* Set logged_trans to a value greater than 0 and less then the
3371	* current transaction to avoid doing the search in future calls.
3372	*/
3373	inode->logged_trans = trans->transid - 1;
3374	return 0;
3375	}
3376
3377	/*
3378	* The inode was previously logged and then evicted, set logged_trans to
3379	* the current transacion's ID, to avoid future tree searches as long as
3380	* the inode is not evicted again.
3381	*/
3382	inode->logged_trans = trans->transid;
3383
3384	/*
3385	* If it's a directory, then we must set last_dir_index_offset to the
3386	* maximum possible value, so that the next attempt to log the inode does
3387	* not skip checking if dir index keys found in modified subvolume tree
3388	* leaves have been logged before, otherwise it would result in attempts
3389	* to insert duplicate dir index keys in the log tree. This must be done
3390	* because last_dir_index_offset is an in-memory only field, not persisted
3391	* in the inode item or any other on-disk structure, so its value is lost
3392	* once the inode is evicted.
3393	*/
3394	if (S_ISDIR(inode->vfs_inode.i_mode))
3395	inode->last_dir_index_offset = (u64)-1;
3396
3397	return 1;
3398	}
3399
3400	/*
3401	* Delete a directory entry from the log if it exists.
3402	*
3403	* Returns < 0 on error
3404	* 1 if the entry does not exists
3405	* 0 if the entry existed and was successfully deleted
3406	*/
3407	static int del_logged_dentry(struct btrfs_trans_handle *trans,
3408	struct btrfs_root *log,
3409	struct btrfs_path *path,
3410	u64 dir_ino,
3411	const struct fscrypt_str *name,
3412	u64 index)
3413	{
3414	struct btrfs_dir_item *di;
3415
3416	/*
3417	* We only log dir index items of a directory, so we don't need to look
3418	* for dir item keys.
3419	*/
3420	di = btrfs_lookup_dir_index_item(trans, root: log, path, dir: dir_ino,
3421	index, name, mod: -1);
3422	if (IS_ERR(ptr: di))
3423	return PTR_ERR(ptr: di);
3424	else if (!di)
3425	return 1;
3426
3427	/*
3428	* We do not need to update the size field of the directory's
3429	* inode item because on log replay we update the field to reflect
3430	* all existing entries in the directory (see overwrite_item()).
3431	*/
3432	return btrfs_delete_one_dir_name(trans, root: log, path, di);
3433	}
3434
3435	/*
3436	* If both a file and directory are logged, and unlinks or renames are
3437	* mixed in, we have a few interesting corners:
3438	*
3439	* create file X in dir Y
3440	* link file X to X.link in dir Y
3441	* fsync file X
3442	* unlink file X but leave X.link
3443	* fsync dir Y
3444	*
3445	* After a crash we would expect only X.link to exist. But file X
3446	* didn't get fsync'd again so the log has back refs for X and X.link.
3447	*
3448	* We solve this by removing directory entries and inode backrefs from the
3449	* log when a file that was logged in the current transaction is
3450	* unlinked. Any later fsync will include the updated log entries, and
3451	* we'll be able to reconstruct the proper directory items from backrefs.
3452	*
3453	* This optimizations allows us to avoid relogging the entire inode
3454	* or the entire directory.
3455	*/
3456	void btrfs_del_dir_entries_in_log(struct btrfs_trans_handle *trans,
3457	struct btrfs_root *root,
3458	const struct fscrypt_str *name,
3459	struct btrfs_inode *dir, u64 index)
3460	{
3461	struct btrfs_path *path;
3462	int ret;
3463
3464	ret = inode_logged(trans, inode: dir, NULL);
3465	if (ret == 0)
3466	return;
3467	else if (ret < 0) {
3468	btrfs_set_log_full_commit(trans);
3469	return;
3470	}
3471
3472	ret = join_running_log_trans(root);
3473	if (ret)
3474	return;
3475
3476	mutex_lock(&dir->log_mutex);
3477
3478	path = btrfs_alloc_path();
3479	if (!path) {
3480	ret = -ENOMEM;
3481	goto out_unlock;
3482	}
3483
3484	ret = del_logged_dentry(trans, log: root->log_root, path, dir_ino: btrfs_ino(inode: dir),
3485	name, index);
3486	btrfs_free_path(p: path);
3487	out_unlock:
3488	mutex_unlock(lock: &dir->log_mutex);
3489	if (ret < 0)
3490	btrfs_set_log_full_commit(trans);
3491	btrfs_end_log_trans(root);
3492	}
3493
3494	/* see comments for btrfs_del_dir_entries_in_log */
3495	void btrfs_del_inode_ref_in_log(struct btrfs_trans_handle *trans,
3496	struct btrfs_root *root,
3497	const struct fscrypt_str *name,
3498	struct btrfs_inode *inode, u64 dirid)
3499	{
3500	struct btrfs_root *log;
3501	u64 index;
3502	int ret;
3503
3504	ret = inode_logged(trans, inode, NULL);
3505	if (ret == 0)
3506	return;
3507	else if (ret < 0) {
3508	btrfs_set_log_full_commit(trans);
3509	return;
3510	}
3511
3512	ret = join_running_log_trans(root);
3513	if (ret)
3514	return;
3515	log = root->log_root;
3516	mutex_lock(&inode->log_mutex);
3517
3518	ret = btrfs_del_inode_ref(trans, root: log, name, inode_objectid: btrfs_ino(inode),
3519	ref_objectid: dirid, index: &index);
3520	mutex_unlock(lock: &inode->log_mutex);
3521	if (ret < 0 && ret != -ENOENT)
3522	btrfs_set_log_full_commit(trans);
3523	btrfs_end_log_trans(root);
3524	}
3525
3526	/*
3527	* creates a range item in the log for 'dirid'. first_offset and
3528	* last_offset tell us which parts of the key space the log should
3529	* be considered authoritative for.
3530	*/
3531	static noinline int insert_dir_log_key(struct btrfs_trans_handle *trans,
3532	struct btrfs_root *log,
3533	struct btrfs_path *path,
3534	u64 dirid,
3535	u64 first_offset, u64 last_offset)
3536	{
3537	int ret;
3538	struct btrfs_key key;
3539	struct btrfs_dir_log_item *item;
3540
3541	key.objectid = dirid;
3542	key.offset = first_offset;
3543	key.type = BTRFS_DIR_LOG_INDEX_KEY;
3544	ret = btrfs_insert_empty_item(trans, root: log, path, key: &key, data_size: sizeof(*item));
3545	/*
3546	* -EEXIST is fine and can happen sporadically when we are logging a
3547	* directory and have concurrent insertions in the subvolume's tree for
3548	* items from other inodes and that result in pushing off some dir items
3549	* from one leaf to another in order to accommodate for the new items.
3550	* This results in logging the same dir index range key.
3551	*/
3552	if (ret && ret != -EEXIST)
3553	return ret;
3554
3555	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
3556	struct btrfs_dir_log_item);
3557	if (ret == -EEXIST) {
3558	const u64 curr_end = btrfs_dir_log_end(eb: path->nodes[0], s: item);
3559
3560	/*
3561	* btrfs_del_dir_entries_in_log() might have been called during
3562	* an unlink between the initial insertion of this key and the
3563	* current update, or we might be logging a single entry deletion
3564	* during a rename, so set the new last_offset to the max value.
3565	*/
3566	last_offset = max(last_offset, curr_end);
3567	}
3568	btrfs_set_dir_log_end(eb: path->nodes[0], s: item, val: last_offset);
3569	btrfs_mark_buffer_dirty(trans, buf: path->nodes[0]);
3570	btrfs_release_path(p: path);
3571	return 0;
3572	}
3573
3574	static int flush_dir_items_batch(struct btrfs_trans_handle *trans,
3575	struct btrfs_inode *inode,
3576	struct extent_buffer *src,
3577	struct btrfs_path *dst_path,
3578	int start_slot,
3579	int count)
3580	{
3581	struct btrfs_root *log = inode->root->log_root;
3582	char *ins_data = NULL;
3583	struct btrfs_item_batch batch;
3584	struct extent_buffer *dst;
3585	unsigned long src_offset;
3586	unsigned long dst_offset;
3587	u64 last_index;
3588	struct btrfs_key key;
3589	u32 item_size;
3590	int ret;
3591	int i;
3592
3593	ASSERT(count > 0);
3594	batch.nr = count;
3595
3596	if (count == 1) {
3597	btrfs_item_key_to_cpu(eb: src, cpu_key: &key, nr: start_slot);
3598	item_size = btrfs_item_size(eb: src, slot: start_slot);
3599	batch.keys = &key;
3600	batch.data_sizes = &item_size;
3601	batch.total_data_size = item_size;
3602	} else {
3603	struct btrfs_key *ins_keys;
3604	u32 *ins_sizes;
3605
3606	ins_data = kmalloc(size: count * sizeof(u32) +
3607	count * sizeof(struct btrfs_key), GFP_NOFS);
3608	if (!ins_data)
3609	return -ENOMEM;
3610
3611	ins_sizes = (u32 *)ins_data;
3612	ins_keys = (struct btrfs_key *)(ins_data + count * sizeof(u32));
3613	batch.keys = ins_keys;
3614	batch.data_sizes = ins_sizes;
3615	batch.total_data_size = 0;
3616
3617	for (i = 0; i < count; i++) {
3618	const int slot = start_slot + i;
3619
3620	btrfs_item_key_to_cpu(eb: src, cpu_key: &ins_keys[i], nr: slot);
3621	ins_sizes[i] = btrfs_item_size(eb: src, slot);
3622	batch.total_data_size += ins_sizes[i];
3623	}
3624	}
3625
3626	ret = btrfs_insert_empty_items(trans, root: log, path: dst_path, batch: &batch);
3627	if (ret)
3628	goto out;
3629
3630	dst = dst_path->nodes[0];
3631	/*
3632	* Copy all the items in bulk, in a single copy operation. Item data is
3633	* organized such that it's placed at the end of a leaf and from right
3634	* to left. For example, the data for the second item ends at an offset
3635	* that matches the offset where the data for the first item starts, the
3636	* data for the third item ends at an offset that matches the offset
3637	* where the data of the second items starts, and so on.
3638	* Therefore our source and destination start offsets for copy match the
3639	* offsets of the last items (highest slots).
3640	*/
3641	dst_offset = btrfs_item_ptr_offset(dst, dst_path->slots[0] + count - 1);
3642	src_offset = btrfs_item_ptr_offset(src, start_slot + count - 1);
3643	copy_extent_buffer(dst, src, dst_offset, src_offset, len: batch.total_data_size);
3644	btrfs_release_path(p: dst_path);
3645
3646	last_index = batch.keys[count - 1].offset;
3647	ASSERT(last_index > inode->last_dir_index_offset);
3648
3649	/*
3650	* If for some unexpected reason the last item's index is not greater
3651	* than the last index we logged, warn and force a transaction commit.
3652	*/
3653	if (WARN_ON(last_index <= inode->last_dir_index_offset))
3654	ret = BTRFS_LOG_FORCE_COMMIT;
3655	else
3656	inode->last_dir_index_offset = last_index;
3657
3658	if (btrfs_get_first_dir_index_to_log(inode) == 0)
3659	btrfs_set_first_dir_index_to_log(inode, index: batch.keys[0].offset);
3660	out:
3661	kfree(objp: ins_data);
3662
3663	return ret;
3664	}
3665
3666	static int clone_leaf(struct btrfs_path *path, struct btrfs_log_ctx *ctx)
3667	{
3668	const int slot = path->slots[0];
3669
3670	if (ctx->scratch_eb) {
3671	copy_extent_buffer_full(dst: ctx->scratch_eb, src: path->nodes[0]);
3672	} else {
3673	ctx->scratch_eb = btrfs_clone_extent_buffer(src: path->nodes[0]);
3674	if (!ctx->scratch_eb)
3675	return -ENOMEM;
3676	}
3677
3678	btrfs_release_path(p: path);
3679	path->nodes[0] = ctx->scratch_eb;
3680	path->slots[0] = slot;
3681	/*
3682	* Add extra ref to scratch eb so that it is not freed when callers
3683	* release the path, so we can reuse it later if needed.
3684	*/
3685	atomic_inc(v: &ctx->scratch_eb->refs);
3686
3687	return 0;
3688	}
3689
3690	static int process_dir_items_leaf(struct btrfs_trans_handle *trans,
3691	struct btrfs_inode *inode,
3692	struct btrfs_path *path,
3693	struct btrfs_path *dst_path,
3694	struct btrfs_log_ctx *ctx,
3695	u64 *last_old_dentry_offset)
3696	{
3697	struct btrfs_root *log = inode->root->log_root;
3698	struct extent_buffer *src;
3699	const int nritems = btrfs_header_nritems(eb: path->nodes[0]);
3700	const u64 ino = btrfs_ino(inode);
3701	bool last_found = false;
3702	int batch_start = 0;
3703	int batch_size = 0;
3704	int ret;
3705
3706	/*
3707	* We need to clone the leaf, release the read lock on it, and use the
3708	* clone before modifying the log tree. See the comment at copy_items()
3709	* about why we need to do this.
3710	*/
3711	ret = clone_leaf(path, ctx);
3712	if (ret < 0)
3713	return ret;
3714
3715	src = path->nodes[0];
3716
3717	for (int i = path->slots[0]; i < nritems; i++) {
3718	struct btrfs_dir_item *di;
3719	struct btrfs_key key;
3720	int ret;
3721
3722	btrfs_item_key_to_cpu(eb: src, cpu_key: &key, nr: i);
3723
3724	if (key.objectid != ino || key.type != BTRFS_DIR_INDEX_KEY) {
3725	last_found = true;
3726	break;
3727	}
3728
3729	di = btrfs_item_ptr(src, i, struct btrfs_dir_item);
3730
3731	/*
3732	* Skip ranges of items that consist only of dir item keys created
3733	* in past transactions. However if we find a gap, we must log a
3734	* dir index range item for that gap, so that index keys in that
3735	* gap are deleted during log replay.
3736	*/
3737	if (btrfs_dir_transid(eb: src, s: di) < trans->transid) {
3738	if (key.offset > *last_old_dentry_offset + 1) {
3739	ret = insert_dir_log_key(trans, log, path: dst_path,
3740	dirid: ino, first_offset: *last_old_dentry_offset + 1,
3741	last_offset: key.offset - 1);
3742	if (ret < 0)
3743	return ret;
3744	}
3745
3746	*last_old_dentry_offset = key.offset;
3747	continue;
3748	}
3749
3750	/* If we logged this dir index item before, we can skip it. */
3751	if (key.offset <= inode->last_dir_index_offset)
3752	continue;
3753
3754	/*
3755	* We must make sure that when we log a directory entry, the
3756	* corresponding inode, after log replay, has a matching link
3757	* count. For example:
3758	*
3759	* touch foo
3760	* mkdir mydir
3761	* sync
3762	* ln foo mydir/bar
3763	* xfs_io -c "fsync" mydir
3764	* <crash>
3765	* <mount fs and log replay>
3766	*
3767	* Would result in a fsync log that when replayed, our file inode
3768	* would have a link count of 1, but we get two directory entries
3769	* pointing to the same inode. After removing one of the names,
3770	* it would not be possible to remove the other name, which
3771	* resulted always in stale file handle errors, and would not be
3772	* possible to rmdir the parent directory, since its i_size could
3773	* never be decremented to the value BTRFS_EMPTY_DIR_SIZE,
3774	* resulting in -ENOTEMPTY errors.
3775	*/
3776	if (!ctx->log_new_dentries) {
3777	struct btrfs_key di_key;
3778
3779	btrfs_dir_item_key_to_cpu(eb: src, item: di, cpu_key: &di_key);
3780	if (di_key.type != BTRFS_ROOT_ITEM_KEY)
3781	ctx->log_new_dentries = true;
3782	}
3783
3784	if (batch_size == 0)
3785	batch_start = i;
3786	batch_size++;
3787	}
3788
3789	if (batch_size > 0) {
3790	int ret;
3791
3792	ret = flush_dir_items_batch(trans, inode, src, dst_path,
3793	start_slot: batch_start, count: batch_size);
3794	if (ret < 0)
3795	return ret;
3796	}
3797
3798	return last_found ? 1 : 0;
3799	}
3800
3801	/*
3802	* log all the items included in the current transaction for a given
3803	* directory. This also creates the range items in the log tree required
3804	* to replay anything deleted before the fsync
3805	*/
3806	static noinline int log_dir_items(struct btrfs_trans_handle *trans,
3807	struct btrfs_inode *inode,
3808	struct btrfs_path *path,
3809	struct btrfs_path *dst_path,
3810	struct btrfs_log_ctx *ctx,
3811	u64 min_offset, u64 *last_offset_ret)
3812	{
3813	struct btrfs_key min_key;
3814	struct btrfs_root *root = inode->root;
3815	struct btrfs_root *log = root->log_root;
3816	int ret;
3817	u64 last_old_dentry_offset = min_offset - 1;
3818	u64 last_offset = (u64)-1;
3819	u64 ino = btrfs_ino(inode);
3820
3821	min_key.objectid = ino;
3822	min_key.type = BTRFS_DIR_INDEX_KEY;
3823	min_key.offset = min_offset;
3824
3825	ret = btrfs_search_forward(root, min_key: &min_key, path, min_trans: trans->transid);
3826
3827	/*
3828	* we didn't find anything from this transaction, see if there
3829	* is anything at all
3830	*/
3831	if (ret != 0 || min_key.objectid != ino ||
3832	min_key.type != BTRFS_DIR_INDEX_KEY) {
3833	min_key.objectid = ino;
3834	min_key.type = BTRFS_DIR_INDEX_KEY;
3835	min_key.offset = (u64)-1;
3836	btrfs_release_path(p: path);
3837	ret = btrfs_search_slot(NULL, root, key: &min_key, p: path, ins_len: 0, cow: 0);
3838	if (ret < 0) {
3839	btrfs_release_path(p: path);
3840	return ret;
3841	}
3842	ret = btrfs_previous_item(root, path, min_objectid: ino, BTRFS_DIR_INDEX_KEY);
3843
3844	/* if ret == 0 there are items for this type,
3845	* create a range to tell us the last key of this type.
3846	* otherwise, there are no items in this directory after
3847	* *min_offset, and we create a range to indicate that.
3848	*/
3849	if (ret == 0) {
3850	struct btrfs_key tmp;
3851
3852	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &tmp,
3853	nr: path->slots[0]);
3854	if (tmp.type == BTRFS_DIR_INDEX_KEY)
3855	last_old_dentry_offset = tmp.offset;
3856	} else if (ret > 0) {
3857	ret = 0;
3858	}
3859
3860	goto done;
3861	}
3862
3863	/* go backward to find any previous key */
3864	ret = btrfs_previous_item(root, path, min_objectid: ino, BTRFS_DIR_INDEX_KEY);
3865	if (ret == 0) {
3866	struct btrfs_key tmp;
3867
3868	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &tmp, nr: path->slots[0]);
3869	/*
3870	* The dir index key before the first one we found that needs to
3871	* be logged might be in a previous leaf, and there might be a
3872	* gap between these keys, meaning that we had deletions that
3873	* happened. So the key range item we log (key type
3874	* BTRFS_DIR_LOG_INDEX_KEY) must cover a range that starts at the
3875	* previous key's offset plus 1, so that those deletes are replayed.
3876	*/
3877	if (tmp.type == BTRFS_DIR_INDEX_KEY)
3878	last_old_dentry_offset = tmp.offset;
3879	} else if (ret < 0) {
3880	goto done;
3881	}
3882
3883	btrfs_release_path(p: path);
3884
3885	/*
3886	* Find the first key from this transaction again or the one we were at
3887	* in the loop below in case we had to reschedule. We may be logging the
3888	* directory without holding its VFS lock, which happen when logging new
3889	* dentries (through log_new_dir_dentries()) or in some cases when we
3890	* need to log the parent directory of an inode. This means a dir index
3891	* key might be deleted from the inode's root, and therefore we may not
3892	* find it anymore. If we can't find it, just move to the next key. We
3893	* can not bail out and ignore, because if we do that we will simply
3894	* not log dir index keys that come after the one that was just deleted
3895	* and we can end up logging a dir index range that ends at (u64)-1
3896	* (@last_offset is initialized to that), resulting in removing dir
3897	* entries we should not remove at log replay time.
3898	*/
3899	search:
3900	ret = btrfs_search_slot(NULL, root, key: &min_key, p: path, ins_len: 0, cow: 0);
3901	if (ret > 0) {
3902	ret = btrfs_next_item(root, p: path);
3903	if (ret > 0) {
3904	/* There are no more keys in the inode's root. */
3905	ret = 0;
3906	goto done;
3907	}
3908	}
3909	if (ret < 0)
3910	goto done;
3911
3912	/*
3913	* we have a block from this transaction, log every item in it
3914	* from our directory
3915	*/
3916	while (1) {
3917	ret = process_dir_items_leaf(trans, inode, path, dst_path, ctx,
3918	last_old_dentry_offset: &last_old_dentry_offset);
3919	if (ret != 0) {
3920	if (ret > 0)
3921	ret = 0;
3922	goto done;
3923	}
3924	path->slots[0] = btrfs_header_nritems(eb: path->nodes[0]);
3925
3926	/*
3927	* look ahead to the next item and see if it is also
3928	* from this directory and from this transaction
3929	*/
3930	ret = btrfs_next_leaf(root, path);
3931	if (ret) {
3932	if (ret == 1) {
3933	last_offset = (u64)-1;
3934	ret = 0;
3935	}
3936	goto done;
3937	}
3938	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &min_key, nr: path->slots[0]);
3939	if (min_key.objectid != ino || min_key.type != BTRFS_DIR_INDEX_KEY) {
3940	last_offset = (u64)-1;
3941	goto done;
3942	}
3943	if (btrfs_header_generation(eb: path->nodes[0]) != trans->transid) {
3944	/*
3945	* The next leaf was not changed in the current transaction
3946	* and has at least one dir index key.
3947	* We check for the next key because there might have been
3948	* one or more deletions between the last key we logged and
3949	* that next key. So the key range item we log (key type
3950	* BTRFS_DIR_LOG_INDEX_KEY) must end at the next key's
3951	* offset minus 1, so that those deletes are replayed.
3952	*/
3953	last_offset = min_key.offset - 1;
3954	goto done;
3955	}
3956	if (need_resched()) {
3957	btrfs_release_path(p: path);
3958	cond_resched();
3959	goto search;
3960	}
3961	}
3962	done:
3963	btrfs_release_path(p: path);
3964	btrfs_release_path(p: dst_path);
3965
3966	if (ret == 0) {
3967	*last_offset_ret = last_offset;
3968	/*
3969	* In case the leaf was changed in the current transaction but
3970	* all its dir items are from a past transaction, the last item
3971	* in the leaf is a dir item and there's no gap between that last
3972	* dir item and the first one on the next leaf (which did not
3973	* change in the current transaction), then we don't need to log
3974	* a range, last_old_dentry_offset is == to last_offset.
3975	*/
3976	ASSERT(last_old_dentry_offset <= last_offset);
3977	if (last_old_dentry_offset < last_offset)
3978	ret = insert_dir_log_key(trans, log, path, dirid: ino,
3979	first_offset: last_old_dentry_offset + 1,
3980	last_offset);
3981	}
3982
3983	return ret;
3984	}
3985
3986	/*
3987	* If the inode was logged before and it was evicted, then its
3988	* last_dir_index_offset is (u64)-1, so we don't the value of the last index
3989	* key offset. If that's the case, search for it and update the inode. This
3990	* is to avoid lookups in the log tree every time we try to insert a dir index
3991	* key from a leaf changed in the current transaction, and to allow us to always
3992	* do batch insertions of dir index keys.
3993	*/
3994	static int update_last_dir_index_offset(struct btrfs_inode *inode,
3995	struct btrfs_path *path,
3996	const struct btrfs_log_ctx *ctx)
3997	{
3998	const u64 ino = btrfs_ino(inode);
3999	struct btrfs_key key;
4000	int ret;
4001
4002	lockdep_assert_held(&inode->log_mutex);
4003
4004	if (inode->last_dir_index_offset != (u64)-1)
4005	return 0;
4006
4007	if (!ctx->logged_before) {
4008	inode->last_dir_index_offset = BTRFS_DIR_START_INDEX - 1;
4009	return 0;
4010	}
4011
4012	key.objectid = ino;
4013	key.type = BTRFS_DIR_INDEX_KEY;
4014	key.offset = (u64)-1;
4015
4016	ret = btrfs_search_slot(NULL, root: inode->root->log_root, key: &key, p: path, ins_len: 0, cow: 0);
4017	/*
4018	* An error happened or we actually have an index key with an offset
4019	* value of (u64)-1. Bail out, we're done.
4020	*/
4021	if (ret <= 0)
4022	goto out;
4023
4024	ret = 0;
4025	inode->last_dir_index_offset = BTRFS_DIR_START_INDEX - 1;
4026
4027	/*
4028	* No dir index items, bail out and leave last_dir_index_offset with
4029	* the value right before the first valid index value.
4030	*/
4031	if (path->slots[0] == 0)
4032	goto out;
4033
4034	/*
4035	* btrfs_search_slot() left us at one slot beyond the slot with the last
4036	* index key, or beyond the last key of the directory that is not an
4037	* index key. If we have an index key before, set last_dir_index_offset
4038	* to its offset value, otherwise leave it with a value right before the
4039	* first valid index value, as it means we have an empty directory.
4040	*/
4041	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0] - 1);
4042	if (key.objectid == ino && key.type == BTRFS_DIR_INDEX_KEY)
4043	inode->last_dir_index_offset = key.offset;
4044
4045	out:
4046	btrfs_release_path(p: path);
4047
4048	return ret;
4049	}
4050
4051	/*
4052	* logging directories is very similar to logging inodes, We find all the items
4053	* from the current transaction and write them to the log.
4054	*
4055	* The recovery code scans the directory in the subvolume, and if it finds a
4056	* key in the range logged that is not present in the log tree, then it means
4057	* that dir entry was unlinked during the transaction.
4058	*
4059	* In order for that scan to work, we must include one key smaller than
4060	* the smallest logged by this transaction and one key larger than the largest
4061	* key logged by this transaction.
4062	*/
4063	static noinline int log_directory_changes(struct btrfs_trans_handle *trans,
4064	struct btrfs_inode *inode,
4065	struct btrfs_path *path,
4066	struct btrfs_path *dst_path,
4067	struct btrfs_log_ctx *ctx)
4068	{
4069	u64 min_key;
4070	u64 max_key;
4071	int ret;
4072
4073	ret = update_last_dir_index_offset(inode, path, ctx);
4074	if (ret)
4075	return ret;
4076
4077	min_key = BTRFS_DIR_START_INDEX;
4078	max_key = 0;
4079
4080	while (1) {
4081	ret = log_dir_items(trans, inode, path, dst_path,
4082	ctx, min_offset: min_key, last_offset_ret: &max_key);
4083	if (ret)
4084	return ret;
4085	if (max_key == (u64)-1)
4086	break;
4087	min_key = max_key + 1;
4088	}
4089
4090	return 0;
4091	}
4092
4093	/*
4094	* a helper function to drop items from the log before we relog an
4095	* inode. max_key_type indicates the highest item type to remove.
4096	* This cannot be run for file data extents because it does not
4097	* free the extents they point to.
4098	*/
4099	static int drop_inode_items(struct btrfs_trans_handle *trans,
4100	struct btrfs_root *log,
4101	struct btrfs_path *path,
4102	struct btrfs_inode *inode,
4103	int max_key_type)
4104	{
4105	int ret;
4106	struct btrfs_key key;
4107	struct btrfs_key found_key;
4108	int start_slot;
4109
4110	key.objectid = btrfs_ino(inode);
4111	key.type = max_key_type;
4112	key.offset = (u64)-1;
4113
4114	while (1) {
4115	ret = btrfs_search_slot(trans, root: log, key: &key, p: path, ins_len: -1, cow: 1);
4116	if (ret < 0) {
4117	break;
4118	} else if (ret > 0) {
4119	if (path->slots[0] == 0)
4120	break;
4121	path->slots[0]--;
4122	}
4123
4124	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &found_key,
4125	nr: path->slots[0]);
4126
4127	if (found_key.objectid != key.objectid)
4128	break;
4129
4130	found_key.offset = 0;
4131	found_key.type = 0;
4132	ret = btrfs_bin_search(eb: path->nodes[0], first_slot: 0, key: &found_key, slot: &start_slot);
4133	if (ret < 0)
4134	break;
4135
4136	ret = btrfs_del_items(trans, root: log, path, slot: start_slot,
4137	nr: path->slots[0] - start_slot + 1);
4138	/*
4139	* If start slot isn't 0 then we don't need to re-search, we've
4140	* found the last guy with the objectid in this tree.
4141	*/
4142	if (ret || start_slot != 0)
4143	break;
4144	btrfs_release_path(p: path);
4145	}
4146	btrfs_release_path(p: path);
4147	if (ret > 0)
4148	ret = 0;
4149	return ret;
4150	}
4151
4152	static int truncate_inode_items(struct btrfs_trans_handle *trans,
4153	struct btrfs_root *log_root,
4154	struct btrfs_inode *inode,
4155	u64 new_size, u32 min_type)
4156	{
4157	struct btrfs_truncate_control control = {
4158	.new_size = new_size,
4159	.ino = btrfs_ino(inode),
4160	.min_type = min_type,
4161	.skip_ref_updates = true,
4162	};
4163
4164	return btrfs_truncate_inode_items(trans, root: log_root, control: &control);
4165	}
4166
4167	static void fill_inode_item(struct btrfs_trans_handle *trans,
4168	struct extent_buffer *leaf,
4169	struct btrfs_inode_item *item,
4170	struct inode *inode, int log_inode_only,
4171	u64 logged_isize)
4172	{
4173	struct btrfs_map_token token;
4174	u64 flags;
4175
4176	btrfs_init_map_token(token: &token, eb: leaf);
4177
4178	if (log_inode_only) {
4179	/* set the generation to zero so the recover code
4180	* can tell the difference between an logging
4181	* just to say 'this inode exists' and a logging
4182	* to say 'update this inode with these values'
4183	*/
4184	btrfs_set_token_inode_generation(token: &token, s: item, val: 0);
4185	btrfs_set_token_inode_size(token: &token, s: item, val: logged_isize);
4186	} else {
4187	btrfs_set_token_inode_generation(token: &token, s: item,
4188	val: BTRFS_I(inode)->generation);
4189	btrfs_set_token_inode_size(token: &token, s: item, val: inode->i_size);
4190	}
4191
4192	btrfs_set_token_inode_uid(token: &token, s: item, val: i_uid_read(inode));
4193	btrfs_set_token_inode_gid(token: &token, s: item, val: i_gid_read(inode));
4194	btrfs_set_token_inode_mode(token: &token, s: item, val: inode->i_mode);
4195	btrfs_set_token_inode_nlink(token: &token, s: item, val: inode->i_nlink);
4196
4197	btrfs_set_token_timespec_sec(token: &token, s: &item->atime,
4198	val: inode_get_atime_sec(inode));
4199	btrfs_set_token_timespec_nsec(token: &token, s: &item->atime,
4200	val: inode_get_atime_nsec(inode));
4201
4202	btrfs_set_token_timespec_sec(token: &token, s: &item->mtime,
4203	val: inode_get_mtime_sec(inode));
4204	btrfs_set_token_timespec_nsec(token: &token, s: &item->mtime,
4205	val: inode_get_mtime_nsec(inode));
4206
4207	btrfs_set_token_timespec_sec(token: &token, s: &item->ctime,
4208	val: inode_get_ctime_sec(inode));
4209	btrfs_set_token_timespec_nsec(token: &token, s: &item->ctime,
4210	val: inode_get_ctime_nsec(inode));
4211
4212	/*
4213	* We do not need to set the nbytes field, in fact during a fast fsync
4214	* its value may not even be correct, since a fast fsync does not wait
4215	* for ordered extent completion, which is where we update nbytes, it
4216	* only waits for writeback to complete. During log replay as we find
4217	* file extent items and replay them, we adjust the nbytes field of the
4218	* inode item in subvolume tree as needed (see overwrite_item()).
4219	*/
4220
4221	btrfs_set_token_inode_sequence(token: &token, s: item, val: inode_peek_iversion(inode));
4222	btrfs_set_token_inode_transid(token: &token, s: item, val: trans->transid);
4223	btrfs_set_token_inode_rdev(token: &token, s: item, val: inode->i_rdev);
4224	flags = btrfs_inode_combine_flags(flags: BTRFS_I(inode)->flags,
4225	ro_flags: BTRFS_I(inode)->ro_flags);
4226	btrfs_set_token_inode_flags(token: &token, s: item, val: flags);
4227	btrfs_set_token_inode_block_group(token: &token, s: item, val: 0);
4228	}
4229
4230	static int log_inode_item(struct btrfs_trans_handle *trans,
4231	struct btrfs_root *log, struct btrfs_path *path,
4232	struct btrfs_inode *inode, bool inode_item_dropped)
4233	{
4234	struct btrfs_inode_item *inode_item;
4235	int ret;
4236
4237	/*
4238	* If we are doing a fast fsync and the inode was logged before in the
4239	* current transaction, then we know the inode was previously logged and
4240	* it exists in the log tree. For performance reasons, in this case use
4241	* btrfs_search_slot() directly with ins_len set to 0 so that we never
4242	* attempt a write lock on the leaf's parent, which adds unnecessary lock
4243	* contention in case there are concurrent fsyncs for other inodes of the
4244	* same subvolume. Using btrfs_insert_empty_item() when the inode item
4245	* already exists can also result in unnecessarily splitting a leaf.
4246	*/
4247	if (!inode_item_dropped && inode->logged_trans == trans->transid) {
4248	ret = btrfs_search_slot(trans, root: log, key: &inode->location, p: path, ins_len: 0, cow: 1);
4249	ASSERT(ret <= 0);
4250	if (ret > 0)
4251	ret = -ENOENT;
4252	} else {
4253	/*
4254	* This means it is the first fsync in the current transaction,
4255	* so the inode item is not in the log and we need to insert it.
4256	* We can never get -EEXIST because we are only called for a fast
4257	* fsync and in case an inode eviction happens after the inode was
4258	* logged before in the current transaction, when we load again
4259	* the inode, we set BTRFS_INODE_NEEDS_FULL_SYNC on its runtime
4260	* flags and set ->logged_trans to 0.
4261	*/
4262	ret = btrfs_insert_empty_item(trans, root: log, path, key: &inode->location,
4263	data_size: sizeof(*inode_item));
4264	ASSERT(ret != -EEXIST);
4265	}
4266	if (ret)
4267	return ret;
4268	inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4269	struct btrfs_inode_item);
4270	fill_inode_item(trans, leaf: path->nodes[0], item: inode_item, inode: &inode->vfs_inode,
4271	log_inode_only: 0, logged_isize: 0);
4272	btrfs_release_path(p: path);
4273	return 0;
4274	}
4275
4276	static int log_csums(struct btrfs_trans_handle *trans,
4277	struct btrfs_inode *inode,
4278	struct btrfs_root *log_root,
4279	struct btrfs_ordered_sum *sums)
4280	{
4281	const u64 lock_end = sums->logical + sums->len - 1;
4282	struct extent_state *cached_state = NULL;
4283	int ret;
4284
4285	/*
4286	* If this inode was not used for reflink operations in the current
4287	* transaction with new extents, then do the fast path, no need to
4288	* worry about logging checksum items with overlapping ranges.
4289	*/
4290	if (inode->last_reflink_trans < trans->transid)
4291	return btrfs_csum_file_blocks(trans, root: log_root, sums);
4292
4293	/*
4294	* Serialize logging for checksums. This is to avoid racing with the
4295	* same checksum being logged by another task that is logging another
4296	* file which happens to refer to the same extent as well. Such races
4297	* can leave checksum items in the log with overlapping ranges.
4298	*/
4299	ret = lock_extent(tree: &log_root->log_csum_range, start: sums->logical, end: lock_end,
4300	cached: &cached_state);
4301	if (ret)
4302	return ret;
4303	/*
4304	* Due to extent cloning, we might have logged a csum item that covers a
4305	* subrange of a cloned extent, and later we can end up logging a csum
4306	* item for a larger subrange of the same extent or the entire range.
4307	* This would leave csum items in the log tree that cover the same range
4308	* and break the searches for checksums in the log tree, resulting in
4309	* some checksums missing in the fs/subvolume tree. So just delete (or
4310	* trim and adjust) any existing csum items in the log for this range.
4311	*/
4312	ret = btrfs_del_csums(trans, root: log_root, bytenr: sums->logical, len: sums->len);
4313	if (!ret)
4314	ret = btrfs_csum_file_blocks(trans, root: log_root, sums);
4315
4316	unlock_extent(tree: &log_root->log_csum_range, start: sums->logical, end: lock_end,
4317	cached: &cached_state);
4318
4319	return ret;
4320	}
4321
4322	static noinline int copy_items(struct btrfs_trans_handle *trans,
4323	struct btrfs_inode *inode,
4324	struct btrfs_path *dst_path,
4325	struct btrfs_path *src_path,
4326	int start_slot, int nr, int inode_only,
4327	u64 logged_isize, struct btrfs_log_ctx *ctx)
4328	{
4329	struct btrfs_root *log = inode->root->log_root;
4330	struct btrfs_file_extent_item *extent;
4331	struct extent_buffer *src;
4332	int ret;
4333	struct btrfs_key *ins_keys;
4334	u32 *ins_sizes;
4335	struct btrfs_item_batch batch;
4336	char *ins_data;
4337	int dst_index;
4338	const bool skip_csum = (inode->flags & BTRFS_INODE_NODATASUM);
4339	const u64 i_size = i_size_read(inode: &inode->vfs_inode);
4340
4341	/*
4342	* To keep lockdep happy and avoid deadlocks, clone the source leaf and
4343	* use the clone. This is because otherwise we would be changing the log
4344	* tree, to insert items from the subvolume tree or insert csum items,
4345	* while holding a read lock on a leaf from the subvolume tree, which
4346	* creates a nasty lock dependency when COWing log tree nodes/leaves:
4347	*
4348	* 1) Modifying the log tree triggers an extent buffer allocation while
4349	* holding a write lock on a parent extent buffer from the log tree.
4350	* Allocating the pages for an extent buffer, or the extent buffer
4351	* struct, can trigger inode eviction and finally the inode eviction
4352	* will trigger a release/remove of a delayed node, which requires
4353	* taking the delayed node's mutex;
4354	*
4355	* 2) Allocating a metadata extent for a log tree can trigger the async
4356	* reclaim thread and make us wait for it to release enough space and
4357	* unblock our reservation ticket. The reclaim thread can start
4358	* flushing delayed items, and that in turn results in the need to
4359	* lock delayed node mutexes and in the need to write lock extent
4360	* buffers of a subvolume tree - all this while holding a write lock
4361	* on the parent extent buffer in the log tree.
4362	*
4363	* So one task in scenario 1) running in parallel with another task in
4364	* scenario 2) could lead to a deadlock, one wanting to lock a delayed
4365	* node mutex while having a read lock on a leaf from the subvolume,
4366	* while the other is holding the delayed node's mutex and wants to
4367	* write lock the same subvolume leaf for flushing delayed items.
4368	*/
4369	ret = clone_leaf(path: src_path, ctx);
4370	if (ret < 0)
4371	return ret;
4372
4373	src = src_path->nodes[0];
4374
4375	ins_data = kmalloc(size: nr * sizeof(struct btrfs_key) +
4376	nr * sizeof(u32), GFP_NOFS);
4377	if (!ins_data)
4378	return -ENOMEM;
4379
4380	ins_sizes = (u32 *)ins_data;
4381	ins_keys = (struct btrfs_key *)(ins_data + nr * sizeof(u32));
4382	batch.keys = ins_keys;
4383	batch.data_sizes = ins_sizes;
4384	batch.total_data_size = 0;
4385	batch.nr = 0;
4386
4387	dst_index = 0;
4388	for (int i = 0; i < nr; i++) {
4389	const int src_slot = start_slot + i;
4390	struct btrfs_root *csum_root;
4391	struct btrfs_ordered_sum *sums;
4392	struct btrfs_ordered_sum *sums_next;
4393	LIST_HEAD(ordered_sums);
4394	u64 disk_bytenr;
4395	u64 disk_num_bytes;
4396	u64 extent_offset;
4397	u64 extent_num_bytes;
4398	bool is_old_extent;
4399
4400	btrfs_item_key_to_cpu(eb: src, cpu_key: &ins_keys[dst_index], nr: src_slot);
4401
4402	if (ins_keys[dst_index].type != BTRFS_EXTENT_DATA_KEY)
4403	goto add_to_batch;
4404
4405	extent = btrfs_item_ptr(src, src_slot,
4406	struct btrfs_file_extent_item);
4407
4408	is_old_extent = (btrfs_file_extent_generation(eb: src, s: extent) <
4409	trans->transid);
4410
4411	/*
4412	* Don't copy extents from past generations. That would make us
4413	* log a lot more metadata for common cases like doing only a
4414	* few random writes into a file and then fsync it for the first
4415	* time or after the full sync flag is set on the inode. We can
4416	* get leaves full of extent items, most of which are from past
4417	* generations, so we can skip them - as long as the inode has
4418	* not been the target of a reflink operation in this transaction,
4419	* as in that case it might have had file extent items with old
4420	* generations copied into it. We also must always log prealloc
4421	* extents that start at or beyond eof, otherwise we would lose
4422	* them on log replay.
4423	*/
4424	if (is_old_extent &&
4425	ins_keys[dst_index].offset < i_size &&
4426	inode->last_reflink_trans < trans->transid)
4427	continue;
4428
4429	if (skip_csum)
4430	goto add_to_batch;
4431
4432	/* Only regular extents have checksums. */
4433	if (btrfs_file_extent_type(eb: src, s: extent) != BTRFS_FILE_EXTENT_REG)
4434	goto add_to_batch;
4435
4436	/*
4437	* If it's an extent created in a past transaction, then its
4438	* checksums are already accessible from the committed csum tree,
4439	* no need to log them.
4440	*/
4441	if (is_old_extent)
4442	goto add_to_batch;
4443
4444	disk_bytenr = btrfs_file_extent_disk_bytenr(eb: src, s: extent);
4445	/* If it's an explicit hole, there are no checksums. */
4446	if (disk_bytenr == 0)
4447	goto add_to_batch;
4448
4449	disk_num_bytes = btrfs_file_extent_disk_num_bytes(eb: src, s: extent);
4450
4451	if (btrfs_file_extent_compression(eb: src, s: extent)) {
4452	extent_offset = 0;
4453	extent_num_bytes = disk_num_bytes;
4454	} else {
4455	extent_offset = btrfs_file_extent_offset(eb: src, s: extent);
4456	extent_num_bytes = btrfs_file_extent_num_bytes(eb: src, s: extent);
4457	}
4458
4459	csum_root = btrfs_csum_root(fs_info: trans->fs_info, bytenr: disk_bytenr);
4460	disk_bytenr += extent_offset;
4461	ret = btrfs_lookup_csums_list(root: csum_root, start: disk_bytenr,
4462	end: disk_bytenr + extent_num_bytes - 1,
4463	list: &ordered_sums, search_commit: 0, nowait: false);
4464	if (ret)
4465	goto out;
4466
4467	list_for_each_entry_safe(sums, sums_next, &ordered_sums, list) {
4468	if (!ret)
4469	ret = log_csums(trans, inode, log_root: log, sums);
4470	list_del(entry: &sums->list);
4471	kfree(objp: sums);
4472	}
4473	if (ret)
4474	goto out;
4475
4476	add_to_batch:
4477	ins_sizes[dst_index] = btrfs_item_size(eb: src, slot: src_slot);
4478	batch.total_data_size += ins_sizes[dst_index];
4479	batch.nr++;
4480	dst_index++;
4481	}
4482
4483	/*
4484	* We have a leaf full of old extent items that don't need to be logged,
4485	* so we don't need to do anything.
4486	*/
4487	if (batch.nr == 0)
4488	goto out;
4489
4490	ret = btrfs_insert_empty_items(trans, root: log, path: dst_path, batch: &batch);
4491	if (ret)
4492	goto out;
4493
4494	dst_index = 0;
4495	for (int i = 0; i < nr; i++) {
4496	const int src_slot = start_slot + i;
4497	const int dst_slot = dst_path->slots[0] + dst_index;
4498	struct btrfs_key key;
4499	unsigned long src_offset;
4500	unsigned long dst_offset;
4501
4502	/*
4503	* We're done, all the remaining items in the source leaf
4504	* correspond to old file extent items.
4505	*/
4506	if (dst_index >= batch.nr)
4507	break;
4508
4509	btrfs_item_key_to_cpu(eb: src, cpu_key: &key, nr: src_slot);
4510
4511	if (key.type != BTRFS_EXTENT_DATA_KEY)
4512	goto copy_item;
4513
4514	extent = btrfs_item_ptr(src, src_slot,
4515	struct btrfs_file_extent_item);
4516
4517	/* See the comment in the previous loop, same logic. */
4518	if (btrfs_file_extent_generation(eb: src, s: extent) < trans->transid &&
4519	key.offset < i_size &&
4520	inode->last_reflink_trans < trans->transid)
4521	continue;
4522
4523	copy_item:
4524	dst_offset = btrfs_item_ptr_offset(dst_path->nodes[0], dst_slot);
4525	src_offset = btrfs_item_ptr_offset(src, src_slot);
4526
4527	if (key.type == BTRFS_INODE_ITEM_KEY) {
4528	struct btrfs_inode_item *inode_item;
4529
4530	inode_item = btrfs_item_ptr(dst_path->nodes[0], dst_slot,
4531	struct btrfs_inode_item);
4532	fill_inode_item(trans, leaf: dst_path->nodes[0], item: inode_item,
4533	inode: &inode->vfs_inode,
4534	log_inode_only: inode_only == LOG_INODE_EXISTS,
4535	logged_isize);
4536	} else {
4537	copy_extent_buffer(dst: dst_path->nodes[0], src, dst_offset,
4538	src_offset, len: ins_sizes[dst_index]);
4539	}
4540
4541	dst_index++;
4542	}
4543
4544	btrfs_mark_buffer_dirty(trans, buf: dst_path->nodes[0]);
4545	btrfs_release_path(p: dst_path);
4546	out:
4547	kfree(objp: ins_data);
4548
4549	return ret;
4550	}
4551
4552	static int extent_cmp(void *priv, const struct list_head *a,
4553	const struct list_head *b)
4554	{
4555	const struct extent_map *em1, *em2;
4556
4557	em1 = list_entry(a, struct extent_map, list);
4558	em2 = list_entry(b, struct extent_map, list);
4559
4560	if (em1->start < em2->start)
4561	return -1;
4562	else if (em1->start > em2->start)
4563	return 1;
4564	return 0;
4565	}
4566
4567	static int log_extent_csums(struct btrfs_trans_handle *trans,
4568	struct btrfs_inode *inode,
4569	struct btrfs_root *log_root,
4570	const struct extent_map *em,
4571	struct btrfs_log_ctx *ctx)
4572	{
4573	struct btrfs_ordered_extent *ordered;
4574	struct btrfs_root *csum_root;
4575	u64 csum_offset;
4576	u64 csum_len;
4577	u64 mod_start = em->mod_start;
4578	u64 mod_len = em->mod_len;
4579	LIST_HEAD(ordered_sums);
4580	int ret = 0;
4581
4582	if (inode->flags & BTRFS_INODE_NODATASUM ||
4583	(em->flags & EXTENT_FLAG_PREALLOC) ||
4584	em->block_start == EXTENT_MAP_HOLE)
4585	return 0;
4586
4587	list_for_each_entry(ordered, &ctx->ordered_extents, log_list) {
4588	const u64 ordered_end = ordered->file_offset + ordered->num_bytes;
4589	const u64 mod_end = mod_start + mod_len;
4590	struct btrfs_ordered_sum *sums;
4591
4592	if (mod_len == 0)
4593	break;
4594
4595	if (ordered_end <= mod_start)
4596	continue;
4597	if (mod_end <= ordered->file_offset)
4598	break;
4599
4600	/*
4601	* We are going to copy all the csums on this ordered extent, so
4602	* go ahead and adjust mod_start and mod_len in case this ordered
4603	* extent has already been logged.
4604	*/
4605	if (ordered->file_offset > mod_start) {
4606	if (ordered_end >= mod_end)
4607	mod_len = ordered->file_offset - mod_start;
4608	/*
4609	* If we have this case
4610	*
4611	* |--------- logged extent ---------|
4612	* |----- ordered extent ----|
4613	*
4614	* Just don't mess with mod_start and mod_len, we'll
4615	* just end up logging more csums than we need and it
4616	* will be ok.
4617	*/
4618	} else {
4619	if (ordered_end < mod_end) {
4620	mod_len = mod_end - ordered_end;
4621	mod_start = ordered_end;
4622	} else {
4623	mod_len = 0;
4624	}
4625	}
4626
4627	/*
4628	* To keep us from looping for the above case of an ordered
4629	* extent that falls inside of the logged extent.
4630	*/
4631	if (test_and_set_bit(nr: BTRFS_ORDERED_LOGGED_CSUM, addr: &ordered->flags))
4632	continue;
4633
4634	list_for_each_entry(sums, &ordered->list, list) {
4635	ret = log_csums(trans, inode, log_root, sums);
4636	if (ret)
4637	return ret;
4638	}
4639	}
4640
4641	/* We're done, found all csums in the ordered extents. */
4642	if (mod_len == 0)
4643	return 0;
4644
4645	/* If we're compressed we have to save the entire range of csums. */
4646	if (extent_map_is_compressed(em)) {
4647	csum_offset = 0;
4648	csum_len = max(em->block_len, em->orig_block_len);
4649	} else {
4650	csum_offset = mod_start - em->start;
4651	csum_len = mod_len;
4652	}
4653
4654	/* block start is already adjusted for the file extent offset. */
4655	csum_root = btrfs_csum_root(fs_info: trans->fs_info, bytenr: em->block_start);
4656	ret = btrfs_lookup_csums_list(root: csum_root, start: em->block_start + csum_offset,
4657	end: em->block_start + csum_offset +
4658	csum_len - 1, list: &ordered_sums, search_commit: 0, nowait: false);
4659	if (ret)
4660	return ret;
4661
4662	while (!list_empty(head: &ordered_sums)) {
4663	struct btrfs_ordered_sum *sums = list_entry(ordered_sums.next,
4664	struct btrfs_ordered_sum,
4665	list);
4666	if (!ret)
4667	ret = log_csums(trans, inode, log_root, sums);
4668	list_del(entry: &sums->list);
4669	kfree(objp: sums);
4670	}
4671
4672	return ret;
4673	}
4674
4675	static int log_one_extent(struct btrfs_trans_handle *trans,
4676	struct btrfs_inode *inode,
4677	const struct extent_map *em,
4678	struct btrfs_path *path,
4679	struct btrfs_log_ctx *ctx)
4680	{
4681	struct btrfs_drop_extents_args drop_args = { 0 };
4682	struct btrfs_root *log = inode->root->log_root;
4683	struct btrfs_file_extent_item fi = { 0 };
4684	struct extent_buffer *leaf;
4685	struct btrfs_key key;
4686	enum btrfs_compression_type compress_type;
4687	u64 extent_offset = em->start - em->orig_start;
4688	u64 block_len;
4689	int ret;
4690
4691	btrfs_set_stack_file_extent_generation(s: &fi, val: trans->transid);
4692	if (em->flags & EXTENT_FLAG_PREALLOC)
4693	btrfs_set_stack_file_extent_type(s: &fi, val: BTRFS_FILE_EXTENT_PREALLOC);
4694	else
4695	btrfs_set_stack_file_extent_type(s: &fi, val: BTRFS_FILE_EXTENT_REG);
4696
4697	block_len = max(em->block_len, em->orig_block_len);
4698	compress_type = extent_map_compression(em);
4699	if (compress_type != BTRFS_COMPRESS_NONE) {
4700	btrfs_set_stack_file_extent_disk_bytenr(s: &fi, val: em->block_start);
4701	btrfs_set_stack_file_extent_disk_num_bytes(s: &fi, val: block_len);
4702	} else if (em->block_start < EXTENT_MAP_LAST_BYTE) {
4703	btrfs_set_stack_file_extent_disk_bytenr(s: &fi, val: em->block_start -
4704	extent_offset);
4705	btrfs_set_stack_file_extent_disk_num_bytes(s: &fi, val: block_len);
4706	}
4707
4708	btrfs_set_stack_file_extent_offset(s: &fi, val: extent_offset);
4709	btrfs_set_stack_file_extent_num_bytes(s: &fi, val: em->len);
4710	btrfs_set_stack_file_extent_ram_bytes(s: &fi, val: em->ram_bytes);
4711	btrfs_set_stack_file_extent_compression(s: &fi, val: compress_type);
4712
4713	ret = log_extent_csums(trans, inode, log_root: log, em, ctx);
4714	if (ret)
4715	return ret;
4716
4717	/*
4718	* If this is the first time we are logging the inode in the current
4719	* transaction, we can avoid btrfs_drop_extents(), which is expensive
4720	* because it does a deletion search, which always acquires write locks
4721	* for extent buffers at levels 2, 1 and 0. This not only wastes time
4722	* but also adds significant contention in a log tree, since log trees
4723	* are small, with a root at level 2 or 3 at most, due to their short
4724	* life span.
4725	*/
4726	if (ctx->logged_before) {
4727	drop_args.path = path;
4728	drop_args.start = em->start;
4729	drop_args.end = em->start + em->len;
4730	drop_args.replace_extent = true;
4731	drop_args.extent_item_size = sizeof(fi);
4732	ret = btrfs_drop_extents(trans, root: log, inode, args: &drop_args);
4733	if (ret)
4734	return ret;
4735	}
4736
4737	if (!drop_args.extent_inserted) {
4738	key.objectid = btrfs_ino(inode);
4739	key.type = BTRFS_EXTENT_DATA_KEY;
4740	key.offset = em->start;
4741
4742	ret = btrfs_insert_empty_item(trans, root: log, path, key: &key,
4743	data_size: sizeof(fi));
4744	if (ret)
4745	return ret;
4746	}
4747	leaf = path->nodes[0];
4748	write_extent_buffer(eb: leaf, src: &fi,
4749	btrfs_item_ptr_offset(leaf, path->slots[0]),
4750	len: sizeof(fi));
4751	btrfs_mark_buffer_dirty(trans, buf: leaf);
4752
4753	btrfs_release_path(p: path);
4754
4755	return ret;
4756	}
4757
4758	/*
4759	* Log all prealloc extents beyond the inode's i_size to make sure we do not
4760	* lose them after doing a full/fast fsync and replaying the log. We scan the
4761	* subvolume's root instead of iterating the inode's extent map tree because
4762	* otherwise we can log incorrect extent items based on extent map conversion.
4763	* That can happen due to the fact that extent maps are merged when they
4764	* are not in the extent map tree's list of modified extents.
4765	*/
4766	static int btrfs_log_prealloc_extents(struct btrfs_trans_handle *trans,
4767	struct btrfs_inode *inode,
4768	struct btrfs_path *path,
4769	struct btrfs_log_ctx *ctx)
4770	{
4771	struct btrfs_root *root = inode->root;
4772	struct btrfs_key key;
4773	const u64 i_size = i_size_read(inode: &inode->vfs_inode);
4774	const u64 ino = btrfs_ino(inode);
4775	struct btrfs_path *dst_path = NULL;
4776	bool dropped_extents = false;
4777	u64 truncate_offset = i_size;
4778	struct extent_buffer *leaf;
4779	int slot;
4780	int ins_nr = 0;
4781	int start_slot = 0;
4782	int ret;
4783
4784	if (!(inode->flags & BTRFS_INODE_PREALLOC))
4785	return 0;
4786
4787	key.objectid = ino;
4788	key.type = BTRFS_EXTENT_DATA_KEY;
4789	key.offset = i_size;
4790	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
4791	if (ret < 0)
4792	goto out;
4793
4794	/*
4795	* We must check if there is a prealloc extent that starts before the
4796	* i_size and crosses the i_size boundary. This is to ensure later we
4797	* truncate down to the end of that extent and not to the i_size, as
4798	* otherwise we end up losing part of the prealloc extent after a log
4799	* replay and with an implicit hole if there is another prealloc extent
4800	* that starts at an offset beyond i_size.
4801	*/
4802	ret = btrfs_previous_item(root, path, min_objectid: ino, BTRFS_EXTENT_DATA_KEY);
4803	if (ret < 0)
4804	goto out;
4805
4806	if (ret == 0) {
4807	struct btrfs_file_extent_item *ei;
4808
4809	leaf = path->nodes[0];
4810	slot = path->slots[0];
4811	ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
4812
4813	if (btrfs_file_extent_type(eb: leaf, s: ei) ==
4814	BTRFS_FILE_EXTENT_PREALLOC) {
4815	u64 extent_end;
4816
4817	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: slot);
4818	extent_end = key.offset +
4819	btrfs_file_extent_num_bytes(eb: leaf, s: ei);
4820
4821	if (extent_end > i_size)
4822	truncate_offset = extent_end;
4823	}
4824	} else {
4825	ret = 0;
4826	}
4827
4828	while (true) {
4829	leaf = path->nodes[0];
4830	slot = path->slots[0];
4831
4832	if (slot >= btrfs_header_nritems(eb: leaf)) {
4833	if (ins_nr > 0) {
4834	ret = copy_items(trans, inode, dst_path, src_path: path,
4835	start_slot, nr: ins_nr, inode_only: 1, logged_isize: 0, ctx);
4836	if (ret < 0)
4837	goto out;
4838	ins_nr = 0;
4839	}
4840	ret = btrfs_next_leaf(root, path);
4841	if (ret < 0)
4842	goto out;
4843	if (ret > 0) {
4844	ret = 0;
4845	break;
4846	}
4847	continue;
4848	}
4849
4850	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: slot);
4851	if (key.objectid > ino)
4852	break;
4853	if (WARN_ON_ONCE(key.objectid < ino) ||
4854	key.type < BTRFS_EXTENT_DATA_KEY ||
4855	key.offset < i_size) {
4856	path->slots[0]++;
4857	continue;
4858	}
4859	if (!dropped_extents) {
4860	/*
4861	* Avoid logging extent items logged in past fsync calls
4862	* and leading to duplicate keys in the log tree.
4863	*/
4864	ret = truncate_inode_items(trans, log_root: root->log_root, inode,
4865	new_size: truncate_offset,
4866	BTRFS_EXTENT_DATA_KEY);
4867	if (ret)
4868	goto out;
4869	dropped_extents = true;
4870	}
4871	if (ins_nr == 0)
4872	start_slot = slot;
4873	ins_nr++;
4874	path->slots[0]++;
4875	if (!dst_path) {
4876	dst_path = btrfs_alloc_path();
4877	if (!dst_path) {
4878	ret = -ENOMEM;
4879	goto out;
4880	}
4881	}
4882	}
4883	if (ins_nr > 0)
4884	ret = copy_items(trans, inode, dst_path, src_path: path,
4885	start_slot, nr: ins_nr, inode_only: 1, logged_isize: 0, ctx);
4886	out:
4887	btrfs_release_path(p: path);
4888	btrfs_free_path(p: dst_path);
4889	return ret;
4890	}
4891
4892	static int btrfs_log_changed_extents(struct btrfs_trans_handle *trans,
4893	struct btrfs_inode *inode,
4894	struct btrfs_path *path,
4895	struct btrfs_log_ctx *ctx)
4896	{
4897	struct btrfs_ordered_extent *ordered;
4898	struct btrfs_ordered_extent *tmp;
4899	struct extent_map *em, *n;
4900	LIST_HEAD(extents);
4901	struct extent_map_tree *tree = &inode->extent_tree;
4902	int ret = 0;
4903	int num = 0;
4904
4905	write_lock(&tree->lock);
4906
4907	list_for_each_entry_safe(em, n, &tree->modified_extents, list) {
4908	list_del_init(entry: &em->list);
4909	/*
4910	* Just an arbitrary number, this can be really CPU intensive
4911	* once we start getting a lot of extents, and really once we
4912	* have a bunch of extents we just want to commit since it will
4913	* be faster.
4914	*/
4915	if (++num > 32768) {
4916	list_del_init(entry: &tree->modified_extents);
4917	ret = -EFBIG;
4918	goto process;
4919	}
4920
4921	if (em->generation < trans->transid)
4922	continue;
4923
4924	/* We log prealloc extents beyond eof later. */
4925	if ((em->flags & EXTENT_FLAG_PREALLOC) &&
4926	em->start >= i_size_read(inode: &inode->vfs_inode))
4927	continue;
4928
4929	/* Need a ref to keep it from getting evicted from cache */
4930	refcount_inc(r: &em->refs);
4931	em->flags |= EXTENT_FLAG_LOGGING;
4932	list_add_tail(new: &em->list, head: &extents);
4933	num++;
4934	}
4935
4936	list_sort(NULL, head: &extents, cmp: extent_cmp);
4937	process:
4938	while (!list_empty(head: &extents)) {
4939	em = list_entry(extents.next, struct extent_map, list);
4940
4941	list_del_init(entry: &em->list);
4942
4943	/*
4944	* If we had an error we just need to delete everybody from our
4945	* private list.
4946	*/
4947	if (ret) {
4948	clear_em_logging(tree, em);
4949	free_extent_map(em);
4950	continue;
4951	}
4952
4953	write_unlock(&tree->lock);
4954
4955	ret = log_one_extent(trans, inode, em, path, ctx);
4956	write_lock(&tree->lock);
4957	clear_em_logging(tree, em);
4958	free_extent_map(em);
4959	}
4960	WARN_ON(!list_empty(&extents));
4961	write_unlock(&tree->lock);
4962
4963	if (!ret)
4964	ret = btrfs_log_prealloc_extents(trans, inode, path, ctx);
4965	if (ret)
4966	return ret;
4967
4968	/*
4969	* We have logged all extents successfully, now make sure the commit of
4970	* the current transaction waits for the ordered extents to complete
4971	* before it commits and wipes out the log trees, otherwise we would
4972	* lose data if an ordered extents completes after the transaction
4973	* commits and a power failure happens after the transaction commit.
4974	*/
4975	list_for_each_entry_safe(ordered, tmp, &ctx->ordered_extents, log_list) {
4976	list_del_init(entry: &ordered->log_list);
4977	set_bit(nr: BTRFS_ORDERED_LOGGED, addr: &ordered->flags);
4978
4979	if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
4980	spin_lock_irq(lock: &inode->ordered_tree_lock);
4981	if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
4982	set_bit(nr: BTRFS_ORDERED_PENDING, addr: &ordered->flags);
4983	atomic_inc(v: &trans->transaction->pending_ordered);
4984	}
4985	spin_unlock_irq(lock: &inode->ordered_tree_lock);
4986	}
4987	btrfs_put_ordered_extent(entry: ordered);
4988	}
4989
4990	return 0;
4991	}
4992
4993	static int logged_inode_size(struct btrfs_root *log, struct btrfs_inode *inode,
4994	struct btrfs_path *path, u64 *size_ret)
4995	{
4996	struct btrfs_key key;
4997	int ret;
4998
4999	key.objectid = btrfs_ino(inode);
5000	key.type = BTRFS_INODE_ITEM_KEY;
5001	key.offset = 0;
5002
5003	ret = btrfs_search_slot(NULL, root: log, key: &key, p: path, ins_len: 0, cow: 0);
5004	if (ret < 0) {
5005	return ret;
5006	} else if (ret > 0) {
5007	*size_ret = 0;
5008	} else {
5009	struct btrfs_inode_item *item;
5010
5011	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5012	struct btrfs_inode_item);
5013	*size_ret = btrfs_inode_size(eb: path->nodes[0], s: item);
5014	/*
5015	* If the in-memory inode's i_size is smaller then the inode
5016	* size stored in the btree, return the inode's i_size, so
5017	* that we get a correct inode size after replaying the log
5018	* when before a power failure we had a shrinking truncate
5019	* followed by addition of a new name (rename / new hard link).
5020	* Otherwise return the inode size from the btree, to avoid
5021	* data loss when replaying a log due to previously doing a
5022	* write that expands the inode's size and logging a new name
5023	* immediately after.
5024	*/
5025	if (*size_ret > inode->vfs_inode.i_size)
5026	*size_ret = inode->vfs_inode.i_size;
5027	}
5028
5029	btrfs_release_path(p: path);
5030	return 0;
5031	}
5032
5033	/*
5034	* At the moment we always log all xattrs. This is to figure out at log replay
5035	* time which xattrs must have their deletion replayed. If a xattr is missing
5036	* in the log tree and exists in the fs/subvol tree, we delete it. This is
5037	* because if a xattr is deleted, the inode is fsynced and a power failure
5038	* happens, causing the log to be replayed the next time the fs is mounted,
5039	* we want the xattr to not exist anymore (same behaviour as other filesystems
5040	* with a journal, ext3/4, xfs, f2fs, etc).
5041	*/
5042	static int btrfs_log_all_xattrs(struct btrfs_trans_handle *trans,
5043	struct btrfs_inode *inode,
5044	struct btrfs_path *path,
5045	struct btrfs_path *dst_path,
5046	struct btrfs_log_ctx *ctx)
5047	{
5048	struct btrfs_root *root = inode->root;
5049	int ret;
5050	struct btrfs_key key;
5051	const u64 ino = btrfs_ino(inode);
5052	int ins_nr = 0;
5053	int start_slot = 0;
5054	bool found_xattrs = false;
5055
5056	if (test_bit(BTRFS_INODE_NO_XATTRS, &inode->runtime_flags))
5057	return 0;
5058
5059	key.objectid = ino;
5060	key.type = BTRFS_XATTR_ITEM_KEY;
5061	key.offset = 0;
5062
5063	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
5064	if (ret < 0)
5065	return ret;
5066
5067	while (true) {
5068	int slot = path->slots[0];
5069	struct extent_buffer *leaf = path->nodes[0];
5070	int nritems = btrfs_header_nritems(eb: leaf);
5071
5072	if (slot >= nritems) {
5073	if (ins_nr > 0) {
5074	ret = copy_items(trans, inode, dst_path, src_path: path,
5075	start_slot, nr: ins_nr, inode_only: 1, logged_isize: 0, ctx);
5076	if (ret < 0)
5077	return ret;
5078	ins_nr = 0;
5079	}
5080	ret = btrfs_next_leaf(root, path);
5081	if (ret < 0)
5082	return ret;
5083	else if (ret > 0)
5084	break;
5085	continue;
5086	}
5087
5088	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: slot);
5089	if (key.objectid != ino || key.type != BTRFS_XATTR_ITEM_KEY)
5090	break;
5091
5092	if (ins_nr == 0)
5093	start_slot = slot;
5094	ins_nr++;
5095	path->slots[0]++;
5096	found_xattrs = true;
5097	cond_resched();
5098	}
5099	if (ins_nr > 0) {
5100	ret = copy_items(trans, inode, dst_path, src_path: path,
5101	start_slot, nr: ins_nr, inode_only: 1, logged_isize: 0, ctx);
5102	if (ret < 0)
5103	return ret;
5104	}
5105
5106	if (!found_xattrs)
5107	set_bit(nr: BTRFS_INODE_NO_XATTRS, addr: &inode->runtime_flags);
5108
5109	return 0;
5110	}
5111
5112	/*
5113	* When using the NO_HOLES feature if we punched a hole that causes the
5114	* deletion of entire leafs or all the extent items of the first leaf (the one
5115	* that contains the inode item and references) we may end up not processing
5116	* any extents, because there are no leafs with a generation matching the
5117	* current transaction that have extent items for our inode. So we need to find
5118	* if any holes exist and then log them. We also need to log holes after any
5119	* truncate operation that changes the inode's size.
5120	*/
5121	static int btrfs_log_holes(struct btrfs_trans_handle *trans,
5122	struct btrfs_inode *inode,
5123	struct btrfs_path *path)
5124	{
5125	struct btrfs_root *root = inode->root;
5126	struct btrfs_fs_info *fs_info = root->fs_info;
5127	struct btrfs_key key;
5128	const u64 ino = btrfs_ino(inode);
5129	const u64 i_size = i_size_read(inode: &inode->vfs_inode);
5130	u64 prev_extent_end = 0;
5131	int ret;
5132
5133	if (!btrfs_fs_incompat(fs_info, NO_HOLES) || i_size == 0)
5134	return 0;
5135
5136	key.objectid = ino;
5137	key.type = BTRFS_EXTENT_DATA_KEY;
5138	key.offset = 0;
5139
5140	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
5141	if (ret < 0)
5142	return ret;
5143
5144	while (true) {
5145	struct extent_buffer *leaf = path->nodes[0];
5146
5147	if (path->slots[0] >= btrfs_header_nritems(eb: path->nodes[0])) {
5148	ret = btrfs_next_leaf(root, path);
5149	if (ret < 0)
5150	return ret;
5151	if (ret > 0) {
5152	ret = 0;
5153	break;
5154	}
5155	leaf = path->nodes[0];
5156	}
5157
5158	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]);
5159	if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY)
5160	break;
5161
5162	/* We have a hole, log it. */
5163	if (prev_extent_end < key.offset) {
5164	const u64 hole_len = key.offset - prev_extent_end;
5165
5166	/*
5167	* Release the path to avoid deadlocks with other code
5168	* paths that search the root while holding locks on
5169	* leafs from the log root.
5170	*/
5171	btrfs_release_path(p: path);
5172	ret = btrfs_insert_hole_extent(trans, root: root->log_root,
5173	objectid: ino, pos: prev_extent_end,
5174	num_bytes: hole_len);
5175	if (ret < 0)
5176	return ret;
5177
5178	/*
5179	* Search for the same key again in the root. Since it's
5180	* an extent item and we are holding the inode lock, the
5181	* key must still exist. If it doesn't just emit warning
5182	* and return an error to fall back to a transaction
5183	* commit.
5184	*/
5185	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
5186	if (ret < 0)
5187	return ret;
5188	if (WARN_ON(ret > 0))
5189	return -ENOENT;
5190	leaf = path->nodes[0];
5191	}
5192
5193	prev_extent_end = btrfs_file_extent_end(path);
5194	path->slots[0]++;
5195	cond_resched();
5196	}
5197
5198	if (prev_extent_end < i_size) {
5199	u64 hole_len;
5200
5201	btrfs_release_path(p: path);
5202	hole_len = ALIGN(i_size - prev_extent_end, fs_info->sectorsize);
5203	ret = btrfs_insert_hole_extent(trans, root: root->log_root, objectid: ino,
5204	pos: prev_extent_end, num_bytes: hole_len);
5205	if (ret < 0)
5206	return ret;
5207	}
5208
5209	return 0;
5210	}
5211
5212	/*
5213	* When we are logging a new inode X, check if it doesn't have a reference that
5214	* matches the reference from some other inode Y created in a past transaction
5215	* and that was renamed in the current transaction. If we don't do this, then at
5216	* log replay time we can lose inode Y (and all its files if it's a directory):
5217	*
5218	* mkdir /mnt/x
5219	* echo "hello world" > /mnt/x/foobar
5220	* sync
5221	* mv /mnt/x /mnt/y
5222	* mkdir /mnt/x # or touch /mnt/x
5223	* xfs_io -c fsync /mnt/x
5224	* <power fail>
5225	* mount fs, trigger log replay
5226	*
5227	* After the log replay procedure, we would lose the first directory and all its
5228	* files (file foobar).
5229	* For the case where inode Y is not a directory we simply end up losing it:
5230	*
5231	* echo "123" > /mnt/foo
5232	* sync
5233	* mv /mnt/foo /mnt/bar
5234	* echo "abc" > /mnt/foo
5235	* xfs_io -c fsync /mnt/foo
5236	* <power fail>
5237	*
5238	* We also need this for cases where a snapshot entry is replaced by some other
5239	* entry (file or directory) otherwise we end up with an unreplayable log due to
5240	* attempts to delete the snapshot entry (entry of type BTRFS_ROOT_ITEM_KEY) as
5241	* if it were a regular entry:
5242	*
5243	* mkdir /mnt/x
5244	* btrfs subvolume snapshot /mnt /mnt/x/snap
5245	* btrfs subvolume delete /mnt/x/snap
5246	* rmdir /mnt/x
5247	* mkdir /mnt/x
5248	* fsync /mnt/x or fsync some new file inside it
5249	* <power fail>
5250	*
5251	* The snapshot delete, rmdir of x, mkdir of a new x and the fsync all happen in
5252	* the same transaction.
5253	*/
5254	static int btrfs_check_ref_name_override(struct extent_buffer *eb,
5255	const int slot,
5256	const struct btrfs_key *key,
5257	struct btrfs_inode *inode,
5258	u64 *other_ino, u64 *other_parent)
5259	{
5260	int ret;
5261	struct btrfs_path *search_path;
5262	char *name = NULL;
5263	u32 name_len = 0;
5264	u32 item_size = btrfs_item_size(eb, slot);
5265	u32 cur_offset = 0;
5266	unsigned long ptr = btrfs_item_ptr_offset(eb, slot);
5267
5268	search_path = btrfs_alloc_path();
5269	if (!search_path)
5270	return -ENOMEM;
5271	search_path->search_commit_root = 1;
5272	search_path->skip_locking = 1;
5273
5274	while (cur_offset < item_size) {
5275	u64 parent;
5276	u32 this_name_len;
5277	u32 this_len;
5278	unsigned long name_ptr;
5279	struct btrfs_dir_item *di;
5280	struct fscrypt_str name_str;
5281
5282	if (key->type == BTRFS_INODE_REF_KEY) {
5283	struct btrfs_inode_ref *iref;
5284
5285	iref = (struct btrfs_inode_ref *)(ptr + cur_offset);
5286	parent = key->offset;
5287	this_name_len = btrfs_inode_ref_name_len(eb, s: iref);
5288	name_ptr = (unsigned long)(iref + 1);
5289	this_len = sizeof(*iref) + this_name_len;
5290	} else {
5291	struct btrfs_inode_extref *extref;
5292
5293	extref = (struct btrfs_inode_extref *)(ptr +
5294	cur_offset);
5295	parent = btrfs_inode_extref_parent(eb, s: extref);
5296	this_name_len = btrfs_inode_extref_name_len(eb, s: extref);
5297	name_ptr = (unsigned long)&extref->name;
5298	this_len = sizeof(*extref) + this_name_len;
5299	}
5300
5301	if (this_name_len > name_len) {
5302	char *new_name;
5303
5304	new_name = krealloc(objp: name, new_size: this_name_len, GFP_NOFS);
5305	if (!new_name) {
5306	ret = -ENOMEM;
5307	goto out;
5308	}
5309	name_len = this_name_len;
5310	name = new_name;
5311	}
5312
5313	read_extent_buffer(eb, dst: name, start: name_ptr, len: this_name_len);
5314
5315	name_str.name = name;
5316	name_str.len = this_name_len;
5317	di = btrfs_lookup_dir_item(NULL, root: inode->root, path: search_path,
5318	dir: parent, name: &name_str, mod: 0);
5319	if (di && !IS_ERR(ptr: di)) {
5320	struct btrfs_key di_key;
5321
5322	btrfs_dir_item_key_to_cpu(eb: search_path->nodes[0],
5323	item: di, cpu_key: &di_key);
5324	if (di_key.type == BTRFS_INODE_ITEM_KEY) {
5325	if (di_key.objectid != key->objectid) {
5326	ret = 1;
5327	*other_ino = di_key.objectid;
5328	*other_parent = parent;
5329	} else {
5330	ret = 0;
5331	}
5332	} else {
5333	ret = -EAGAIN;
5334	}
5335	goto out;
5336	} else if (IS_ERR(ptr: di)) {
5337	ret = PTR_ERR(ptr: di);
5338	goto out;
5339	}
5340	btrfs_release_path(p: search_path);
5341
5342	cur_offset += this_len;
5343	}
5344	ret = 0;
5345	out:
5346	btrfs_free_path(p: search_path);
5347	kfree(objp: name);
5348	return ret;
5349	}
5350
5351	/*
5352	* Check if we need to log an inode. This is used in contexts where while
5353	* logging an inode we need to log another inode (either that it exists or in
5354	* full mode). This is used instead of btrfs_inode_in_log() because the later
5355	* requires the inode to be in the log and have the log transaction committed,
5356	* while here we do not care if the log transaction was already committed - our
5357	* caller will commit the log later - and we want to avoid logging an inode
5358	* multiple times when multiple tasks have joined the same log transaction.
5359	*/
5360	static bool need_log_inode(const struct btrfs_trans_handle *trans,
5361	struct btrfs_inode *inode)
5362	{
5363	/*
5364	* If a directory was not modified, no dentries added or removed, we can
5365	* and should avoid logging it.
5366	*/
5367	if (S_ISDIR(inode->vfs_inode.i_mode) && inode->last_trans < trans->transid)
5368	return false;
5369
5370	/*
5371	* If this inode does not have new/updated/deleted xattrs since the last
5372	* time it was logged and is flagged as logged in the current transaction,
5373	* we can skip logging it. As for new/deleted names, those are updated in
5374	* the log by link/unlink/rename operations.
5375	* In case the inode was logged and then evicted and reloaded, its
5376	* logged_trans will be 0, in which case we have to fully log it since
5377	* logged_trans is a transient field, not persisted.
5378	*/
5379	if (inode_logged(trans, inode, NULL) == 1 &&
5380	!test_bit(BTRFS_INODE_COPY_EVERYTHING, &inode->runtime_flags))
5381	return false;
5382
5383	return true;
5384	}
5385
5386	struct btrfs_dir_list {
5387	u64 ino;
5388	struct list_head list;
5389	};
5390
5391	/*
5392	* Log the inodes of the new dentries of a directory.
5393	* See process_dir_items_leaf() for details about why it is needed.
5394	* This is a recursive operation - if an existing dentry corresponds to a
5395	* directory, that directory's new entries are logged too (same behaviour as
5396	* ext3/4, xfs, f2fs, reiserfs, nilfs2). Note that when logging the inodes
5397	* the dentries point to we do not acquire their VFS lock, otherwise lockdep
5398	* complains about the following circular lock dependency / possible deadlock:
5399	*
5400	* CPU0 CPU1
5401	* ---- ----
5402	* lock(&type->i_mutex_dir_key#3/2);
5403	* lock(sb_internal#2);
5404	* lock(&type->i_mutex_dir_key#3/2);
5405	* lock(&sb->s_type->i_mutex_key#14);
5406	*
5407	* Where sb_internal is the lock (a counter that works as a lock) acquired by
5408	* sb_start_intwrite() in btrfs_start_transaction().
5409	* Not acquiring the VFS lock of the inodes is still safe because:
5410	*
5411	* 1) For regular files we log with a mode of LOG_INODE_EXISTS. It's possible
5412	* that while logging the inode new references (names) are added or removed
5413	* from the inode, leaving the logged inode item with a link count that does
5414	* not match the number of logged inode reference items. This is fine because
5415	* at log replay time we compute the real number of links and correct the
5416	* link count in the inode item (see replay_one_buffer() and
5417	* link_to_fixup_dir());
5418	*
5419	* 2) For directories we log with a mode of LOG_INODE_ALL. It's possible that
5420	* while logging the inode's items new index items (key type
5421	* BTRFS_DIR_INDEX_KEY) are added to fs/subvol tree and the logged inode item
5422	* has a size that doesn't match the sum of the lengths of all the logged
5423	* names - this is ok, not a problem, because at log replay time we set the
5424	* directory's i_size to the correct value (see replay_one_name() and
5425	* overwrite_item()).
5426	*/
5427	static int log_new_dir_dentries(struct btrfs_trans_handle *trans,
5428	struct btrfs_inode *start_inode,
5429	struct btrfs_log_ctx *ctx)
5430	{
5431	struct btrfs_root *root = start_inode->root;
5432	struct btrfs_fs_info *fs_info = root->fs_info;
5433	struct btrfs_path *path;
5434	LIST_HEAD(dir_list);
5435	struct btrfs_dir_list *dir_elem;
5436	u64 ino = btrfs_ino(inode: start_inode);
5437	struct btrfs_inode *curr_inode = start_inode;
5438	int ret = 0;
5439
5440	/*
5441	* If we are logging a new name, as part of a link or rename operation,
5442	* don't bother logging new dentries, as we just want to log the names
5443	* of an inode and that any new parents exist.
5444	*/
5445	if (ctx->logging_new_name)
5446	return 0;
5447
5448	path = btrfs_alloc_path();
5449	if (!path)
5450	return -ENOMEM;
5451
5452	/* Pairs with btrfs_add_delayed_iput below. */
5453	ihold(inode: &curr_inode->vfs_inode);
5454
5455	while (true) {
5456	struct inode *vfs_inode;
5457	struct btrfs_key key;
5458	struct btrfs_key found_key;
5459	u64 next_index;
5460	bool continue_curr_inode = true;
5461	int iter_ret;
5462
5463	key.objectid = ino;
5464	key.type = BTRFS_DIR_INDEX_KEY;
5465	key.offset = btrfs_get_first_dir_index_to_log(inode: curr_inode);
5466	next_index = key.offset;
5467	again:
5468	btrfs_for_each_slot(root->log_root, &key, &found_key, path, iter_ret) {
5469	struct extent_buffer *leaf = path->nodes[0];
5470	struct btrfs_dir_item *di;
5471	struct btrfs_key di_key;
5472	struct inode *di_inode;
5473	int log_mode = LOG_INODE_EXISTS;
5474	int type;
5475
5476	if (found_key.objectid != ino ||
5477	found_key.type != BTRFS_DIR_INDEX_KEY) {
5478	continue_curr_inode = false;
5479	break;
5480	}
5481
5482	next_index = found_key.offset + 1;
5483
5484	di = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
5485	type = btrfs_dir_ftype(eb: leaf, item: di);
5486	if (btrfs_dir_transid(eb: leaf, s: di) < trans->transid)
5487	continue;
5488	btrfs_dir_item_key_to_cpu(eb: leaf, item: di, cpu_key: &di_key);
5489	if (di_key.type == BTRFS_ROOT_ITEM_KEY)
5490	continue;
5491
5492	btrfs_release_path(p: path);
5493	di_inode = btrfs_iget(s: fs_info->sb, ino: di_key.objectid, root);
5494	if (IS_ERR(ptr: di_inode)) {
5495	ret = PTR_ERR(ptr: di_inode);
5496	goto out;
5497	}
5498
5499	if (!need_log_inode(trans, inode: BTRFS_I(inode: di_inode))) {
5500	btrfs_add_delayed_iput(inode: BTRFS_I(inode: di_inode));
5501	break;
5502	}
5503
5504	ctx->log_new_dentries = false;
5505	if (type == BTRFS_FT_DIR)
5506	log_mode = LOG_INODE_ALL;
5507	ret = btrfs_log_inode(trans, inode: BTRFS_I(inode: di_inode),
5508	inode_only: log_mode, ctx);
5509	btrfs_add_delayed_iput(inode: BTRFS_I(inode: di_inode));
5510	if (ret)
5511	goto out;
5512	if (ctx->log_new_dentries) {
5513	dir_elem = kmalloc(size: sizeof(*dir_elem), GFP_NOFS);
5514	if (!dir_elem) {
5515	ret = -ENOMEM;
5516	goto out;
5517	}
5518	dir_elem->ino = di_key.objectid;
5519	list_add_tail(new: &dir_elem->list, head: &dir_list);
5520	}
5521	break;
5522	}
5523
5524	btrfs_release_path(p: path);
5525
5526	if (iter_ret < 0) {
5527	ret = iter_ret;
5528	goto out;
5529	} else if (iter_ret > 0) {
5530	continue_curr_inode = false;
5531	} else {
5532	key = found_key;
5533	}
5534
5535	if (continue_curr_inode && key.offset < (u64)-1) {
5536	key.offset++;
5537	goto again;
5538	}
5539
5540	btrfs_set_first_dir_index_to_log(inode: curr_inode, index: next_index);
5541
5542	if (list_empty(head: &dir_list))
5543	break;
5544
5545	dir_elem = list_first_entry(&dir_list, struct btrfs_dir_list, list);
5546	ino = dir_elem->ino;
5547	list_del(entry: &dir_elem->list);
5548	kfree(objp: dir_elem);
5549
5550	btrfs_add_delayed_iput(inode: curr_inode);
5551	curr_inode = NULL;
5552
5553	vfs_inode = btrfs_iget(s: fs_info->sb, ino, root);
5554	if (IS_ERR(ptr: vfs_inode)) {
5555	ret = PTR_ERR(ptr: vfs_inode);
5556	break;
5557	}
5558	curr_inode = BTRFS_I(inode: vfs_inode);
5559	}
5560	out:
5561	btrfs_free_path(p: path);
5562	if (curr_inode)
5563	btrfs_add_delayed_iput(inode: curr_inode);
5564
5565	if (ret) {
5566	struct btrfs_dir_list *next;
5567
5568	list_for_each_entry_safe(dir_elem, next, &dir_list, list)
5569	kfree(objp: dir_elem);
5570	}
5571
5572	return ret;
5573	}
5574
5575	struct btrfs_ino_list {
5576	u64 ino;
5577	u64 parent;
5578	struct list_head list;
5579	};
5580
5581	static void free_conflicting_inodes(struct btrfs_log_ctx *ctx)
5582	{
5583	struct btrfs_ino_list *curr;
5584	struct btrfs_ino_list *next;
5585
5586	list_for_each_entry_safe(curr, next, &ctx->conflict_inodes, list) {
5587	list_del(entry: &curr->list);
5588	kfree(objp: curr);
5589	}
5590	}
5591
5592	static int conflicting_inode_is_dir(struct btrfs_root *root, u64 ino,
5593	struct btrfs_path *path)
5594	{
5595	struct btrfs_key key;
5596	int ret;
5597
5598	key.objectid = ino;
5599	key.type = BTRFS_INODE_ITEM_KEY;
5600	key.offset = 0;
5601
5602	path->search_commit_root = 1;
5603	path->skip_locking = 1;
5604
5605	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
5606	if (WARN_ON_ONCE(ret > 0)) {
5607	/*
5608	* We have previously found the inode through the commit root
5609	* so this should not happen. If it does, just error out and
5610	* fallback to a transaction commit.
5611	*/
5612	ret = -ENOENT;
5613	} else if (ret == 0) {
5614	struct btrfs_inode_item *item;
5615
5616	item = btrfs_item_ptr(path->nodes[0], path->slots[0],
5617	struct btrfs_inode_item);
5618	if (S_ISDIR(btrfs_inode_mode(path->nodes[0], item)))
5619	ret = 1;
5620	}
5621
5622	btrfs_release_path(p: path);
5623	path->search_commit_root = 0;
5624	path->skip_locking = 0;
5625
5626	return ret;
5627	}
5628
5629	static int add_conflicting_inode(struct btrfs_trans_handle *trans,
5630	struct btrfs_root *root,
5631	struct btrfs_path *path,
5632	u64 ino, u64 parent,
5633	struct btrfs_log_ctx *ctx)
5634	{
5635	struct btrfs_ino_list *ino_elem;
5636	struct inode *inode;
5637
5638	/*
5639	* It's rare to have a lot of conflicting inodes, in practice it is not
5640	* common to have more than 1 or 2. We don't want to collect too many,
5641	* as we could end up logging too many inodes (even if only in
5642	* LOG_INODE_EXISTS mode) and slow down other fsyncs or transaction
5643	* commits.
5644	*/
5645	if (ctx->num_conflict_inodes >= MAX_CONFLICT_INODES)
5646	return BTRFS_LOG_FORCE_COMMIT;
5647
5648	inode = btrfs_iget(s: root->fs_info->sb, ino, root);
5649	/*
5650	* If the other inode that had a conflicting dir entry was deleted in
5651	* the current transaction then we either:
5652	*
5653	* 1) Log the parent directory (later after adding it to the list) if
5654	* the inode is a directory. This is because it may be a deleted
5655	* subvolume/snapshot or it may be a regular directory that had
5656	* deleted subvolumes/snapshots (or subdirectories that had them),
5657	* and at the moment we can't deal with dropping subvolumes/snapshots
5658	* during log replay. So we just log the parent, which will result in
5659	* a fallback to a transaction commit if we are dealing with those
5660	* cases (last_unlink_trans will match the current transaction);
5661	*
5662	* 2) Do nothing if it's not a directory. During log replay we simply
5663	* unlink the conflicting dentry from the parent directory and then
5664	* add the dentry for our inode. Like this we can avoid logging the
5665	* parent directory (and maybe fallback to a transaction commit in
5666	* case it has a last_unlink_trans == trans->transid, due to moving
5667	* some inode from it to some other directory).
5668	*/
5669	if (IS_ERR(ptr: inode)) {
5670	int ret = PTR_ERR(ptr: inode);
5671
5672	if (ret != -ENOENT)
5673	return ret;
5674
5675	ret = conflicting_inode_is_dir(root, ino, path);
5676	/* Not a directory or we got an error. */
5677	if (ret <= 0)
5678	return ret;
5679
5680	/* Conflicting inode is a directory, so we'll log its parent. */
5681	ino_elem = kmalloc(size: sizeof(*ino_elem), GFP_NOFS);
5682	if (!ino_elem)
5683	return -ENOMEM;
5684	ino_elem->ino = ino;
5685	ino_elem->parent = parent;
5686	list_add_tail(new: &ino_elem->list, head: &ctx->conflict_inodes);
5687	ctx->num_conflict_inodes++;
5688
5689	return 0;
5690	}
5691
5692	/*
5693	* If the inode was already logged skip it - otherwise we can hit an
5694	* infinite loop. Example:
5695	*
5696	* From the commit root (previous transaction) we have the following
5697	* inodes:
5698	*
5699	* inode 257 a directory
5700	* inode 258 with references "zz" and "zz_link" on inode 257
5701	* inode 259 with reference "a" on inode 257
5702	*
5703	* And in the current (uncommitted) transaction we have:
5704	*
5705	* inode 257 a directory, unchanged
5706	* inode 258 with references "a" and "a2" on inode 257
5707	* inode 259 with reference "zz_link" on inode 257
5708	* inode 261 with reference "zz" on inode 257
5709	*
5710	* When logging inode 261 the following infinite loop could
5711	* happen if we don't skip already logged inodes:
5712	*
5713	* - we detect inode 258 as a conflicting inode, with inode 261
5714	* on reference "zz", and log it;
5715	*
5716	* - we detect inode 259 as a conflicting inode, with inode 258
5717	* on reference "a", and log it;
5718	*
5719	* - we detect inode 258 as a conflicting inode, with inode 259
5720	* on reference "zz_link", and log it - again! After this we
5721	* repeat the above steps forever.
5722	*
5723	* Here we can use need_log_inode() because we only need to log the
5724	* inode in LOG_INODE_EXISTS mode and rename operations update the log,
5725	* so that the log ends up with the new name and without the old name.
5726	*/
5727	if (!need_log_inode(trans, inode: BTRFS_I(inode))) {
5728	btrfs_add_delayed_iput(inode: BTRFS_I(inode));
5729	return 0;
5730	}
5731
5732	btrfs_add_delayed_iput(inode: BTRFS_I(inode));
5733
5734	ino_elem = kmalloc(size: sizeof(*ino_elem), GFP_NOFS);
5735	if (!ino_elem)
5736	return -ENOMEM;
5737	ino_elem->ino = ino;
5738	ino_elem->parent = parent;
5739	list_add_tail(new: &ino_elem->list, head: &ctx->conflict_inodes);
5740	ctx->num_conflict_inodes++;
5741
5742	return 0;
5743	}
5744
5745	static int log_conflicting_inodes(struct btrfs_trans_handle *trans,
5746	struct btrfs_root *root,
5747	struct btrfs_log_ctx *ctx)
5748	{
5749	struct btrfs_fs_info *fs_info = root->fs_info;
5750	int ret = 0;
5751
5752	/*
5753	* Conflicting inodes are logged by the first call to btrfs_log_inode(),
5754	* otherwise we could have unbounded recursion of btrfs_log_inode()
5755	* calls. This check guarantees we can have only 1 level of recursion.
5756	*/
5757	if (ctx->logging_conflict_inodes)
5758	return 0;
5759
5760	ctx->logging_conflict_inodes = true;
5761
5762	/*
5763	* New conflicting inodes may be found and added to the list while we
5764	* are logging a conflicting inode, so keep iterating while the list is
5765	* not empty.
5766	*/
5767	while (!list_empty(head: &ctx->conflict_inodes)) {
5768	struct btrfs_ino_list *curr;
5769	struct inode *inode;
5770	u64 ino;
5771	u64 parent;
5772
5773	curr = list_first_entry(&ctx->conflict_inodes,
5774	struct btrfs_ino_list, list);
5775	ino = curr->ino;
5776	parent = curr->parent;
5777	list_del(entry: &curr->list);
5778	kfree(objp: curr);
5779
5780	inode = btrfs_iget(s: fs_info->sb, ino, root);
5781	/*
5782	* If the other inode that had a conflicting dir entry was
5783	* deleted in the current transaction, we need to log its parent
5784	* directory. See the comment at add_conflicting_inode().
5785	*/
5786	if (IS_ERR(ptr: inode)) {
5787	ret = PTR_ERR(ptr: inode);
5788	if (ret != -ENOENT)
5789	break;
5790
5791	inode = btrfs_iget(s: fs_info->sb, ino: parent, root);
5792	if (IS_ERR(ptr: inode)) {
5793	ret = PTR_ERR(ptr: inode);
5794	break;
5795	}
5796
5797	/*
5798	* Always log the directory, we cannot make this
5799	* conditional on need_log_inode() because the directory
5800	* might have been logged in LOG_INODE_EXISTS mode or
5801	* the dir index of the conflicting inode is not in a
5802	* dir index key range logged for the directory. So we
5803	* must make sure the deletion is recorded.
5804	*/
5805	ret = btrfs_log_inode(trans, inode: BTRFS_I(inode),
5806	inode_only: LOG_INODE_ALL, ctx);
5807	btrfs_add_delayed_iput(inode: BTRFS_I(inode));
5808	if (ret)
5809	break;
5810	continue;
5811	}
5812
5813	/*
5814	* Here we can use need_log_inode() because we only need to log
5815	* the inode in LOG_INODE_EXISTS mode and rename operations
5816	* update the log, so that the log ends up with the new name and
5817	* without the old name.
5818	*
5819	* We did this check at add_conflicting_inode(), but here we do
5820	* it again because if some other task logged the inode after
5821	* that, we can avoid doing it again.
5822	*/
5823	if (!need_log_inode(trans, inode: BTRFS_I(inode))) {
5824	btrfs_add_delayed_iput(inode: BTRFS_I(inode));
5825	continue;
5826	}
5827
5828	/*
5829	* We are safe logging the other inode without acquiring its
5830	* lock as long as we log with the LOG_INODE_EXISTS mode. We
5831	* are safe against concurrent renames of the other inode as
5832	* well because during a rename we pin the log and update the
5833	* log with the new name before we unpin it.
5834	*/
5835	ret = btrfs_log_inode(trans, inode: BTRFS_I(inode), inode_only: LOG_INODE_EXISTS, ctx);
5836	btrfs_add_delayed_iput(inode: BTRFS_I(inode));
5837	if (ret)
5838	break;
5839	}
5840
5841	ctx->logging_conflict_inodes = false;
5842	if (ret)
5843	free_conflicting_inodes(ctx);
5844
5845	return ret;
5846	}
5847
5848	static int copy_inode_items_to_log(struct btrfs_trans_handle *trans,
5849	struct btrfs_inode *inode,
5850	struct btrfs_key *min_key,
5851	const struct btrfs_key *max_key,
5852	struct btrfs_path *path,
5853	struct btrfs_path *dst_path,
5854	const u64 logged_isize,
5855	const int inode_only,
5856	struct btrfs_log_ctx *ctx,
5857	bool *need_log_inode_item)
5858	{
5859	const u64 i_size = i_size_read(inode: &inode->vfs_inode);
5860	struct btrfs_root *root = inode->root;
5861	int ins_start_slot = 0;
5862	int ins_nr = 0;
5863	int ret;
5864
5865	while (1) {
5866	ret = btrfs_search_forward(root, min_key, path, min_trans: trans->transid);
5867	if (ret < 0)
5868	return ret;
5869	if (ret > 0) {
5870	ret = 0;
5871	break;
5872	}
5873	again:
5874	/* Note, ins_nr might be > 0 here, cleanup outside the loop */
5875	if (min_key->objectid != max_key->objectid)
5876	break;
5877	if (min_key->type > max_key->type)
5878	break;
5879
5880	if (min_key->type == BTRFS_INODE_ITEM_KEY) {
5881	*need_log_inode_item = false;
5882	} else if (min_key->type == BTRFS_EXTENT_DATA_KEY &&
5883	min_key->offset >= i_size) {
5884	/*
5885	* Extents at and beyond eof are logged with
5886	* btrfs_log_prealloc_extents().
5887	* Only regular files have BTRFS_EXTENT_DATA_KEY keys,
5888	* and no keys greater than that, so bail out.
5889	*/
5890	break;
5891	} else if ((min_key->type == BTRFS_INODE_REF_KEY ||
5892	min_key->type == BTRFS_INODE_EXTREF_KEY) &&
5893	(inode->generation == trans->transid ||
5894	ctx->logging_conflict_inodes)) {
5895	u64 other_ino = 0;
5896	u64 other_parent = 0;
5897
5898	ret = btrfs_check_ref_name_override(eb: path->nodes[0],
5899	slot: path->slots[0], key: min_key, inode,
5900	other_ino: &other_ino, other_parent: &other_parent);
5901	if (ret < 0) {
5902	return ret;
5903	} else if (ret > 0 &&
5904	other_ino != btrfs_ino(inode: BTRFS_I(inode: ctx->inode))) {
5905	if (ins_nr > 0) {
5906	ins_nr++;
5907	} else {
5908	ins_nr = 1;
5909	ins_start_slot = path->slots[0];
5910	}
5911	ret = copy_items(trans, inode, dst_path, src_path: path,
5912	start_slot: ins_start_slot, nr: ins_nr,
5913	inode_only, logged_isize, ctx);
5914	if (ret < 0)
5915	return ret;
5916	ins_nr = 0;
5917
5918	btrfs_release_path(p: path);
5919	ret = add_conflicting_inode(trans, root, path,
5920	ino: other_ino,
5921	parent: other_parent, ctx);
5922	if (ret)
5923	return ret;
5924	goto next_key;
5925	}
5926	} else if (min_key->type == BTRFS_XATTR_ITEM_KEY) {
5927	/* Skip xattrs, logged later with btrfs_log_all_xattrs() */
5928	if (ins_nr == 0)
5929	goto next_slot;
5930	ret = copy_items(trans, inode, dst_path, src_path: path,
5931	start_slot: ins_start_slot,
5932	nr: ins_nr, inode_only, logged_isize, ctx);
5933	if (ret < 0)
5934	return ret;
5935	ins_nr = 0;
5936	goto next_slot;
5937	}
5938
5939	if (ins_nr && ins_start_slot + ins_nr == path->slots[0]) {
5940	ins_nr++;
5941	goto next_slot;
5942	} else if (!ins_nr) {
5943	ins_start_slot = path->slots[0];
5944	ins_nr = 1;
5945	goto next_slot;
5946	}
5947
5948	ret = copy_items(trans, inode, dst_path, src_path: path, start_slot: ins_start_slot,
5949	nr: ins_nr, inode_only, logged_isize, ctx);
5950	if (ret < 0)
5951	return ret;
5952	ins_nr = 1;
5953	ins_start_slot = path->slots[0];
5954	next_slot:
5955	path->slots[0]++;
5956	if (path->slots[0] < btrfs_header_nritems(eb: path->nodes[0])) {
5957	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: min_key,
5958	nr: path->slots[0]);
5959	goto again;
5960	}
5961	if (ins_nr) {
5962	ret = copy_items(trans, inode, dst_path, src_path: path,
5963	start_slot: ins_start_slot, nr: ins_nr, inode_only,
5964	logged_isize, ctx);
5965	if (ret < 0)
5966	return ret;
5967	ins_nr = 0;
5968	}
5969	btrfs_release_path(p: path);
5970	next_key:
5971	if (min_key->offset < (u64)-1) {
5972	min_key->offset++;
5973	} else if (min_key->type < max_key->type) {
5974	min_key->type++;
5975	min_key->offset = 0;
5976	} else {
5977	break;
5978	}
5979
5980	/*
5981	* We may process many leaves full of items for our inode, so
5982	* avoid monopolizing a cpu for too long by rescheduling while
5983	* not holding locks on any tree.
5984	*/
5985	cond_resched();
5986	}
5987	if (ins_nr) {
5988	ret = copy_items(trans, inode, dst_path, src_path: path, start_slot: ins_start_slot,
5989	nr: ins_nr, inode_only, logged_isize, ctx);
5990	if (ret)
5991	return ret;
5992	}
5993
5994	if (inode_only == LOG_INODE_ALL && S_ISREG(inode->vfs_inode.i_mode)) {
5995	/*
5996	* Release the path because otherwise we might attempt to double
5997	* lock the same leaf with btrfs_log_prealloc_extents() below.
5998	*/
5999	btrfs_release_path(p: path);
6000	ret = btrfs_log_prealloc_extents(trans, inode, path: dst_path, ctx);
6001	}
6002
6003	return ret;
6004	}
6005
6006	static int insert_delayed_items_batch(struct btrfs_trans_handle *trans,
6007	struct btrfs_root *log,
6008	struct btrfs_path *path,
6009	const struct btrfs_item_batch *batch,
6010	const struct btrfs_delayed_item *first_item)
6011	{
6012	const struct btrfs_delayed_item *curr = first_item;
6013	int ret;
6014
6015	ret = btrfs_insert_empty_items(trans, root: log, path, batch);
6016	if (ret)
6017	return ret;
6018
6019	for (int i = 0; i < batch->nr; i++) {
6020	char *data_ptr;
6021
6022	data_ptr = btrfs_item_ptr(path->nodes[0], path->slots[0], char);
6023	write_extent_buffer(eb: path->nodes[0], src: &curr->data,
6024	start: (unsigned long)data_ptr, len: curr->data_len);
6025	curr = list_next_entry(curr, log_list);
6026	path->slots[0]++;
6027	}
6028
6029	btrfs_release_path(p: path);
6030
6031	return 0;
6032	}
6033
6034	static int log_delayed_insertion_items(struct btrfs_trans_handle *trans,
6035	struct btrfs_inode *inode,
6036	struct btrfs_path *path,
6037	const struct list_head *delayed_ins_list,
6038	struct btrfs_log_ctx *ctx)
6039	{
6040	/* 195 (4095 bytes of keys and sizes) fits in a single 4K page. */
6041	const int max_batch_size = 195;
6042	const int leaf_data_size = BTRFS_LEAF_DATA_SIZE(info: trans->fs_info);
6043	const u64 ino = btrfs_ino(inode);
6044	struct btrfs_root *log = inode->root->log_root;
6045	struct btrfs_item_batch batch = {
6046	.nr = 0,
6047	.total_data_size = 0,
6048	};
6049	const struct btrfs_delayed_item *first = NULL;
6050	const struct btrfs_delayed_item *curr;
6051	char *ins_data;
6052	struct btrfs_key *ins_keys;
6053	u32 *ins_sizes;
6054	u64 curr_batch_size = 0;
6055	int batch_idx = 0;
6056	int ret;
6057
6058	/* We are adding dir index items to the log tree. */
6059	lockdep_assert_held(&inode->log_mutex);
6060
6061	/*
6062	* We collect delayed items before copying index keys from the subvolume
6063	* to the log tree. However just after we collected them, they may have
6064	* been flushed (all of them or just some of them), and therefore we
6065	* could have copied them from the subvolume tree to the log tree.
6066	* So find the first delayed item that was not yet logged (they are
6067	* sorted by index number).
6068	*/
6069	list_for_each_entry(curr, delayed_ins_list, log_list) {
6070	if (curr->index > inode->last_dir_index_offset) {
6071	first = curr;
6072	break;
6073	}
6074	}
6075
6076	/* Empty list or all delayed items were already logged. */
6077	if (!first)
6078	return 0;
6079
6080	ins_data = kmalloc(size: max_batch_size * sizeof(u32) +
6081	max_batch_size * sizeof(struct btrfs_key), GFP_NOFS);
6082	if (!ins_data)
6083	return -ENOMEM;
6084	ins_sizes = (u32 *)ins_data;
6085	batch.data_sizes = ins_sizes;
6086	ins_keys = (struct btrfs_key *)(ins_data + max_batch_size * sizeof(u32));
6087	batch.keys = ins_keys;
6088
6089	curr = first;
6090	while (!list_entry_is_head(curr, delayed_ins_list, log_list)) {
6091	const u32 curr_size = curr->data_len + sizeof(struct btrfs_item);
6092
6093	if (curr_batch_size + curr_size > leaf_data_size ||
6094	batch.nr == max_batch_size) {
6095	ret = insert_delayed_items_batch(trans, log, path,
6096	batch: &batch, first_item: first);
6097	if (ret)
6098	goto out;
6099	batch_idx = 0;
6100	batch.nr = 0;
6101	batch.total_data_size = 0;
6102	curr_batch_size = 0;
6103	first = curr;
6104	}
6105
6106	ins_sizes[batch_idx] = curr->data_len;
6107	ins_keys[batch_idx].objectid = ino;
6108	ins_keys[batch_idx].type = BTRFS_DIR_INDEX_KEY;
6109	ins_keys[batch_idx].offset = curr->index;
6110	curr_batch_size += curr_size;
6111	batch.total_data_size += curr->data_len;
6112	batch.nr++;
6113	batch_idx++;
6114	curr = list_next_entry(curr, log_list);
6115	}
6116
6117	ASSERT(batch.nr >= 1);
6118	ret = insert_delayed_items_batch(trans, log, path, batch: &batch, first_item: first);
6119
6120	curr = list_last_entry(delayed_ins_list, struct btrfs_delayed_item,
6121	log_list);
6122	inode->last_dir_index_offset = curr->index;
6123	out:
6124	kfree(objp: ins_data);
6125
6126	return ret;
6127	}
6128
6129	static int log_delayed_deletions_full(struct btrfs_trans_handle *trans,
6130	struct btrfs_inode *inode,
6131	struct btrfs_path *path,
6132	const struct list_head *delayed_del_list,
6133	struct btrfs_log_ctx *ctx)
6134	{
6135	const u64 ino = btrfs_ino(inode);
6136	const struct btrfs_delayed_item *curr;
6137
6138	curr = list_first_entry(delayed_del_list, struct btrfs_delayed_item,
6139	log_list);
6140
6141	while (!list_entry_is_head(curr, delayed_del_list, log_list)) {
6142	u64 first_dir_index = curr->index;
6143	u64 last_dir_index;
6144	const struct btrfs_delayed_item *next;
6145	int ret;
6146
6147	/*
6148	* Find a range of consecutive dir index items to delete. Like
6149	* this we log a single dir range item spanning several contiguous
6150	* dir items instead of logging one range item per dir index item.
6151	*/
6152	next = list_next_entry(curr, log_list);
6153	while (!list_entry_is_head(next, delayed_del_list, log_list)) {
6154	if (next->index != curr->index + 1)
6155	break;
6156	curr = next;
6157	next = list_next_entry(next, log_list);
6158	}
6159
6160	last_dir_index = curr->index;
6161	ASSERT(last_dir_index >= first_dir_index);
6162
6163	ret = insert_dir_log_key(trans, log: inode->root->log_root, path,
6164	dirid: ino, first_offset: first_dir_index, last_offset: last_dir_index);
6165	if (ret)
6166	return ret;
6167	curr = list_next_entry(curr, log_list);
6168	}
6169
6170	return 0;
6171	}
6172
6173	static int batch_delete_dir_index_items(struct btrfs_trans_handle *trans,
6174	struct btrfs_inode *inode,
6175	struct btrfs_path *path,
6176	struct btrfs_log_ctx *ctx,
6177	const struct list_head *delayed_del_list,
6178	const struct btrfs_delayed_item *first,
6179	const struct btrfs_delayed_item **last_ret)
6180	{
6181	const struct btrfs_delayed_item *next;
6182	struct extent_buffer *leaf = path->nodes[0];
6183	const int last_slot = btrfs_header_nritems(eb: leaf) - 1;
6184	int slot = path->slots[0] + 1;
6185	const u64 ino = btrfs_ino(inode);
6186
6187	next = list_next_entry(first, log_list);
6188
6189	while (slot < last_slot &&
6190	!list_entry_is_head(next, delayed_del_list, log_list)) {
6191	struct btrfs_key key;
6192
6193	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: slot);
6194	if (key.objectid != ino ||
6195	key.type != BTRFS_DIR_INDEX_KEY ||
6196	key.offset != next->index)
6197	break;
6198
6199	slot++;
6200	*last_ret = next;
6201	next = list_next_entry(next, log_list);
6202	}
6203
6204	return btrfs_del_items(trans, root: inode->root->log_root, path,
6205	slot: path->slots[0], nr: slot - path->slots[0]);
6206	}
6207
6208	static int log_delayed_deletions_incremental(struct btrfs_trans_handle *trans,
6209	struct btrfs_inode *inode,
6210	struct btrfs_path *path,
6211	const struct list_head *delayed_del_list,
6212	struct btrfs_log_ctx *ctx)
6213	{
6214	struct btrfs_root *log = inode->root->log_root;
6215	const struct btrfs_delayed_item *curr;
6216	u64 last_range_start = 0;
6217	u64 last_range_end = 0;
6218	struct btrfs_key key;
6219
6220	key.objectid = btrfs_ino(inode);
6221	key.type = BTRFS_DIR_INDEX_KEY;
6222	curr = list_first_entry(delayed_del_list, struct btrfs_delayed_item,
6223	log_list);
6224
6225	while (!list_entry_is_head(curr, delayed_del_list, log_list)) {
6226	const struct btrfs_delayed_item *last = curr;
6227	u64 first_dir_index = curr->index;
6228	u64 last_dir_index;
6229	bool deleted_items = false;
6230	int ret;
6231
6232	key.offset = curr->index;
6233	ret = btrfs_search_slot(trans, root: log, key: &key, p: path, ins_len: -1, cow: 1);
6234	if (ret < 0) {
6235	return ret;
6236	} else if (ret == 0) {
6237	ret = batch_delete_dir_index_items(trans, inode, path, ctx,
6238	delayed_del_list, first: curr,
6239	last_ret: &last);
6240	if (ret)
6241	return ret;
6242	deleted_items = true;
6243	}
6244
6245	btrfs_release_path(p: path);
6246
6247	/*
6248	* If we deleted items from the leaf, it means we have a range
6249	* item logging their range, so no need to add one or update an
6250	* existing one. Otherwise we have to log a dir range item.
6251	*/
6252	if (deleted_items)
6253	goto next_batch;
6254
6255	last_dir_index = last->index;
6256	ASSERT(last_dir_index >= first_dir_index);
6257	/*
6258	* If this range starts right after where the previous one ends,
6259	* then we want to reuse the previous range item and change its
6260	* end offset to the end of this range. This is just to minimize
6261	* leaf space usage, by avoiding adding a new range item.
6262	*/
6263	if (last_range_end != 0 && first_dir_index == last_range_end + 1)
6264	first_dir_index = last_range_start;
6265
6266	ret = insert_dir_log_key(trans, log, path, dirid: key.objectid,
6267	first_offset: first_dir_index, last_offset: last_dir_index);
6268	if (ret)
6269	return ret;
6270
6271	last_range_start = first_dir_index;
6272	last_range_end = last_dir_index;
6273	next_batch:
6274	curr = list_next_entry(last, log_list);
6275	}
6276
6277	return 0;
6278	}
6279
6280	static int log_delayed_deletion_items(struct btrfs_trans_handle *trans,
6281	struct btrfs_inode *inode,
6282	struct btrfs_path *path,
6283	const struct list_head *delayed_del_list,
6284	struct btrfs_log_ctx *ctx)
6285	{
6286	/*
6287	* We are deleting dir index items from the log tree or adding range
6288	* items to it.
6289	*/
6290	lockdep_assert_held(&inode->log_mutex);
6291
6292	if (list_empty(head: delayed_del_list))
6293	return 0;
6294
6295	if (ctx->logged_before)
6296	return log_delayed_deletions_incremental(trans, inode, path,
6297	delayed_del_list, ctx);
6298
6299	return log_delayed_deletions_full(trans, inode, path, delayed_del_list,
6300	ctx);
6301	}
6302
6303	/*
6304	* Similar logic as for log_new_dir_dentries(), but it iterates over the delayed
6305	* items instead of the subvolume tree.
6306	*/
6307	static int log_new_delayed_dentries(struct btrfs_trans_handle *trans,
6308	struct btrfs_inode *inode,
6309	const struct list_head *delayed_ins_list,
6310	struct btrfs_log_ctx *ctx)
6311	{
6312	const bool orig_log_new_dentries = ctx->log_new_dentries;
6313	struct btrfs_fs_info *fs_info = trans->fs_info;
6314	struct btrfs_delayed_item *item;
6315	int ret = 0;
6316
6317	/*
6318	* No need for the log mutex, plus to avoid potential deadlocks or
6319	* lockdep annotations due to nesting of delayed inode mutexes and log
6320	* mutexes.
6321	*/
6322	lockdep_assert_not_held(&inode->log_mutex);
6323
6324	ASSERT(!ctx->logging_new_delayed_dentries);
6325	ctx->logging_new_delayed_dentries = true;
6326
6327	list_for_each_entry(item, delayed_ins_list, log_list) {
6328	struct btrfs_dir_item *dir_item;
6329	struct inode *di_inode;
6330	struct btrfs_key key;
6331	int log_mode = LOG_INODE_EXISTS;
6332
6333	dir_item = (struct btrfs_dir_item *)item->data;
6334	btrfs_disk_key_to_cpu(cpu_key: &key, disk_key: &dir_item->location);
6335
6336	if (key.type == BTRFS_ROOT_ITEM_KEY)
6337	continue;
6338
6339	di_inode = btrfs_iget(s: fs_info->sb, ino: key.objectid, root: inode->root);
6340	if (IS_ERR(ptr: di_inode)) {
6341	ret = PTR_ERR(ptr: di_inode);
6342	break;
6343	}
6344
6345	if (!need_log_inode(trans, inode: BTRFS_I(inode: di_inode))) {
6346	btrfs_add_delayed_iput(inode: BTRFS_I(inode: di_inode));
6347	continue;
6348	}
6349
6350	if (btrfs_stack_dir_ftype(item: dir_item) == BTRFS_FT_DIR)
6351	log_mode = LOG_INODE_ALL;
6352
6353	ctx->log_new_dentries = false;
6354	ret = btrfs_log_inode(trans, inode: BTRFS_I(inode: di_inode), inode_only: log_mode, ctx);
6355
6356	if (!ret && ctx->log_new_dentries)
6357	ret = log_new_dir_dentries(trans, start_inode: BTRFS_I(inode: di_inode), ctx);
6358
6359	btrfs_add_delayed_iput(inode: BTRFS_I(inode: di_inode));
6360
6361	if (ret)
6362	break;
6363	}
6364
6365	ctx->log_new_dentries = orig_log_new_dentries;
6366	ctx->logging_new_delayed_dentries = false;
6367
6368	return ret;
6369	}
6370
6371	/* log a single inode in the tree log.
6372	* At least one parent directory for this inode must exist in the tree
6373	* or be logged already.
6374	*
6375	* Any items from this inode changed by the current transaction are copied
6376	* to the log tree. An extra reference is taken on any extents in this
6377	* file, allowing us to avoid a whole pile of corner cases around logging
6378	* blocks that have been removed from the tree.
6379	*
6380	* See LOG_INODE_ALL and related defines for a description of what inode_only
6381	* does.
6382	*
6383	* This handles both files and directories.
6384	*/
6385	static int btrfs_log_inode(struct btrfs_trans_handle *trans,
6386	struct btrfs_inode *inode,
6387	int inode_only,
6388	struct btrfs_log_ctx *ctx)
6389	{
6390	struct btrfs_path *path;
6391	struct btrfs_path *dst_path;
6392	struct btrfs_key min_key;
6393	struct btrfs_key max_key;
6394	struct btrfs_root *log = inode->root->log_root;
6395	int ret;
6396	bool fast_search = false;
6397	u64 ino = btrfs_ino(inode);
6398	struct extent_map_tree *em_tree = &inode->extent_tree;
6399	u64 logged_isize = 0;
6400	bool need_log_inode_item = true;
6401	bool xattrs_logged = false;
6402	bool inode_item_dropped = true;
6403	bool full_dir_logging = false;
6404	LIST_HEAD(delayed_ins_list);
6405	LIST_HEAD(delayed_del_list);
6406
6407	path = btrfs_alloc_path();
6408	if (!path)
6409	return -ENOMEM;
6410	dst_path = btrfs_alloc_path();
6411	if (!dst_path) {
6412	btrfs_free_path(p: path);
6413	return -ENOMEM;
6414	}
6415
6416	min_key.objectid = ino;
6417	min_key.type = BTRFS_INODE_ITEM_KEY;
6418	min_key.offset = 0;
6419
6420	max_key.objectid = ino;
6421
6422
6423	/* today the code can only do partial logging of directories */
6424	if (S_ISDIR(inode->vfs_inode.i_mode) ||
6425	(!test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
6426	&inode->runtime_flags) &&
6427	inode_only >= LOG_INODE_EXISTS))
6428	max_key.type = BTRFS_XATTR_ITEM_KEY;
6429	else
6430	max_key.type = (u8)-1;
6431	max_key.offset = (u64)-1;
6432
6433	if (S_ISDIR(inode->vfs_inode.i_mode) && inode_only == LOG_INODE_ALL)
6434	full_dir_logging = true;
6435
6436	/*
6437	* If we are logging a directory while we are logging dentries of the
6438	* delayed items of some other inode, then we need to flush the delayed
6439	* items of this directory and not log the delayed items directly. This
6440	* is to prevent more than one level of recursion into btrfs_log_inode()
6441	* by having something like this:
6442	*
6443	* $ mkdir -p a/b/c/d/e/f/g/h/...
6444	* $ xfs_io -c "fsync" a
6445	*
6446	* Where all directories in the path did not exist before and are
6447	* created in the current transaction.
6448	* So in such a case we directly log the delayed items of the main
6449	* directory ("a") without flushing them first, while for each of its
6450	* subdirectories we flush their delayed items before logging them.
6451	* This prevents a potential unbounded recursion like this:
6452	*
6453	* btrfs_log_inode()
6454	* log_new_delayed_dentries()
6455	* btrfs_log_inode()
6456	* log_new_delayed_dentries()
6457	* btrfs_log_inode()
6458	* log_new_delayed_dentries()
6459	* (...)
6460	*
6461	* We have thresholds for the maximum number of delayed items to have in
6462	* memory, and once they are hit, the items are flushed asynchronously.
6463	* However the limit is quite high, so lets prevent deep levels of
6464	* recursion to happen by limiting the maximum depth to be 1.
6465	*/
6466	if (full_dir_logging && ctx->logging_new_delayed_dentries) {
6467	ret = btrfs_commit_inode_delayed_items(trans, inode);
6468	if (ret)
6469	goto out;
6470	}
6471
6472	mutex_lock(&inode->log_mutex);
6473
6474	/*
6475	* For symlinks, we must always log their content, which is stored in an
6476	* inline extent, otherwise we could end up with an empty symlink after
6477	* log replay, which is invalid on linux (symlink(2) returns -ENOENT if
6478	* one attempts to create an empty symlink).
6479	* We don't need to worry about flushing delalloc, because when we create
6480	* the inline extent when the symlink is created (we never have delalloc
6481	* for symlinks).
6482	*/
6483	if (S_ISLNK(inode->vfs_inode.i_mode))
6484	inode_only = LOG_INODE_ALL;
6485
6486	/*
6487	* Before logging the inode item, cache the value returned by
6488	* inode_logged(), because after that we have the need to figure out if
6489	* the inode was previously logged in this transaction.
6490	*/
6491	ret = inode_logged(trans, inode, path_in: path);
6492	if (ret < 0)
6493	goto out_unlock;
6494	ctx->logged_before = (ret == 1);
6495	ret = 0;
6496
6497	/*
6498	* This is for cases where logging a directory could result in losing a
6499	* a file after replaying the log. For example, if we move a file from a
6500	* directory A to a directory B, then fsync directory A, we have no way
6501	* to known the file was moved from A to B, so logging just A would
6502	* result in losing the file after a log replay.
6503	*/
6504	if (full_dir_logging && inode->last_unlink_trans >= trans->transid) {
6505	ret = BTRFS_LOG_FORCE_COMMIT;
6506	goto out_unlock;
6507	}
6508
6509	/*
6510	* a brute force approach to making sure we get the most uptodate
6511	* copies of everything.
6512	*/
6513	if (S_ISDIR(inode->vfs_inode.i_mode)) {
6514	clear_bit(nr: BTRFS_INODE_COPY_EVERYTHING, addr: &inode->runtime_flags);
6515	if (ctx->logged_before)
6516	ret = drop_inode_items(trans, log, path, inode,
6517	BTRFS_XATTR_ITEM_KEY);
6518	} else {
6519	if (inode_only == LOG_INODE_EXISTS && ctx->logged_before) {
6520	/*
6521	* Make sure the new inode item we write to the log has
6522	* the same isize as the current one (if it exists).
6523	* This is necessary to prevent data loss after log
6524	* replay, and also to prevent doing a wrong expanding
6525	* truncate - for e.g. create file, write 4K into offset
6526	* 0, fsync, write 4K into offset 4096, add hard link,
6527	* fsync some other file (to sync log), power fail - if
6528	* we use the inode's current i_size, after log replay
6529	* we get a 8Kb file, with the last 4Kb extent as a hole
6530	* (zeroes), as if an expanding truncate happened,
6531	* instead of getting a file of 4Kb only.
6532	*/
6533	ret = logged_inode_size(log, inode, path, size_ret: &logged_isize);
6534	if (ret)
6535	goto out_unlock;
6536	}
6537	if (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
6538	&inode->runtime_flags)) {
6539	if (inode_only == LOG_INODE_EXISTS) {
6540	max_key.type = BTRFS_XATTR_ITEM_KEY;
6541	if (ctx->logged_before)
6542	ret = drop_inode_items(trans, log, path,
6543	inode, max_key_type: max_key.type);
6544	} else {
6545	clear_bit(nr: BTRFS_INODE_NEEDS_FULL_SYNC,
6546	addr: &inode->runtime_flags);
6547	clear_bit(nr: BTRFS_INODE_COPY_EVERYTHING,
6548	addr: &inode->runtime_flags);
6549	if (ctx->logged_before)
6550	ret = truncate_inode_items(trans, log_root: log,
6551	inode, new_size: 0, min_type: 0);
6552	}
6553	} else if (test_and_clear_bit(nr: BTRFS_INODE_COPY_EVERYTHING,
6554	addr: &inode->runtime_flags) ||
6555	inode_only == LOG_INODE_EXISTS) {
6556	if (inode_only == LOG_INODE_ALL)
6557	fast_search = true;
6558	max_key.type = BTRFS_XATTR_ITEM_KEY;
6559	if (ctx->logged_before)
6560	ret = drop_inode_items(trans, log, path, inode,
6561	max_key_type: max_key.type);
6562	} else {
6563	if (inode_only == LOG_INODE_ALL)
6564	fast_search = true;
6565	inode_item_dropped = false;
6566	goto log_extents;
6567	}
6568
6569	}
6570	if (ret)
6571	goto out_unlock;
6572
6573	/*
6574	* If we are logging a directory in full mode, collect the delayed items
6575	* before iterating the subvolume tree, so that we don't miss any new
6576	* dir index items in case they get flushed while or right after we are
6577	* iterating the subvolume tree.
6578	*/
6579	if (full_dir_logging && !ctx->logging_new_delayed_dentries)
6580	btrfs_log_get_delayed_items(inode, ins_list: &delayed_ins_list,
6581	del_list: &delayed_del_list);
6582
6583	ret = copy_inode_items_to_log(trans, inode, min_key: &min_key, max_key: &max_key,
6584	path, dst_path, logged_isize,
6585	inode_only, ctx,
6586	need_log_inode_item: &need_log_inode_item);
6587	if (ret)
6588	goto out_unlock;
6589
6590	btrfs_release_path(p: path);
6591	btrfs_release_path(p: dst_path);
6592	ret = btrfs_log_all_xattrs(trans, inode, path, dst_path, ctx);
6593	if (ret)
6594	goto out_unlock;
6595	xattrs_logged = true;
6596	if (max_key.type >= BTRFS_EXTENT_DATA_KEY && !fast_search) {
6597	btrfs_release_path(p: path);
6598	btrfs_release_path(p: dst_path);
6599	ret = btrfs_log_holes(trans, inode, path);
6600	if (ret)
6601	goto out_unlock;
6602	}
6603	log_extents:
6604	btrfs_release_path(p: path);
6605	btrfs_release_path(p: dst_path);
6606	if (need_log_inode_item) {
6607	ret = log_inode_item(trans, log, path: dst_path, inode, inode_item_dropped);
6608	if (ret)
6609	goto out_unlock;
6610	/*
6611	* If we are doing a fast fsync and the inode was logged before
6612	* in this transaction, we don't need to log the xattrs because
6613	* they were logged before. If xattrs were added, changed or
6614	* deleted since the last time we logged the inode, then we have
6615	* already logged them because the inode had the runtime flag
6616	* BTRFS_INODE_COPY_EVERYTHING set.
6617	*/
6618	if (!xattrs_logged && inode->logged_trans < trans->transid) {
6619	ret = btrfs_log_all_xattrs(trans, inode, path, dst_path, ctx);
6620	if (ret)
6621	goto out_unlock;
6622	btrfs_release_path(p: path);
6623	}
6624	}
6625	if (fast_search) {
6626	ret = btrfs_log_changed_extents(trans, inode, path: dst_path, ctx);
6627	if (ret)
6628	goto out_unlock;
6629	} else if (inode_only == LOG_INODE_ALL) {
6630	struct extent_map *em, *n;
6631
6632	write_lock(&em_tree->lock);
6633	list_for_each_entry_safe(em, n, &em_tree->modified_extents, list)
6634	list_del_init(entry: &em->list);
6635	write_unlock(&em_tree->lock);
6636	}
6637
6638	if (full_dir_logging) {
6639	ret = log_directory_changes(trans, inode, path, dst_path, ctx);
6640	if (ret)
6641	goto out_unlock;
6642	ret = log_delayed_insertion_items(trans, inode, path,
6643	delayed_ins_list: &delayed_ins_list, ctx);
6644	if (ret)
6645	goto out_unlock;
6646	ret = log_delayed_deletion_items(trans, inode, path,
6647	delayed_del_list: &delayed_del_list, ctx);
6648	if (ret)
6649	goto out_unlock;
6650	}
6651
6652	spin_lock(lock: &inode->lock);
6653	inode->logged_trans = trans->transid;
6654	/*
6655	* Don't update last_log_commit if we logged that an inode exists.
6656	* We do this for three reasons:
6657	*
6658	* 1) We might have had buffered writes to this inode that were
6659	* flushed and had their ordered extents completed in this
6660	* transaction, but we did not previously log the inode with
6661	* LOG_INODE_ALL. Later the inode was evicted and after that
6662	* it was loaded again and this LOG_INODE_EXISTS log operation
6663	* happened. We must make sure that if an explicit fsync against
6664	* the inode is performed later, it logs the new extents, an
6665	* updated inode item, etc, and syncs the log. The same logic
6666	* applies to direct IO writes instead of buffered writes.
6667	*
6668	* 2) When we log the inode with LOG_INODE_EXISTS, its inode item
6669	* is logged with an i_size of 0 or whatever value was logged
6670	* before. If later the i_size of the inode is increased by a
6671	* truncate operation, the log is synced through an fsync of
6672	* some other inode and then finally an explicit fsync against
6673	* this inode is made, we must make sure this fsync logs the
6674	* inode with the new i_size, the hole between old i_size and
6675	* the new i_size, and syncs the log.
6676	*
6677	* 3) If we are logging that an ancestor inode exists as part of
6678	* logging a new name from a link or rename operation, don't update
6679	* its last_log_commit - otherwise if an explicit fsync is made
6680	* against an ancestor, the fsync considers the inode in the log
6681	* and doesn't sync the log, resulting in the ancestor missing after
6682	* a power failure unless the log was synced as part of an fsync
6683	* against any other unrelated inode.
6684	*/
6685	if (inode_only != LOG_INODE_EXISTS)
6686	inode->last_log_commit = inode->last_sub_trans;
6687	spin_unlock(lock: &inode->lock);
6688
6689	/*
6690	* Reset the last_reflink_trans so that the next fsync does not need to
6691	* go through the slower path when logging extents and their checksums.
6692	*/
6693	if (inode_only == LOG_INODE_ALL)
6694	inode->last_reflink_trans = 0;
6695
6696	out_unlock:
6697	mutex_unlock(lock: &inode->log_mutex);
6698	out:
6699	btrfs_free_path(p: path);
6700	btrfs_free_path(p: dst_path);
6701
6702	if (ret)
6703	free_conflicting_inodes(ctx);
6704	else
6705	ret = log_conflicting_inodes(trans, root: inode->root, ctx);
6706
6707	if (full_dir_logging && !ctx->logging_new_delayed_dentries) {
6708	if (!ret)
6709	ret = log_new_delayed_dentries(trans, inode,
6710	delayed_ins_list: &delayed_ins_list, ctx);
6711
6712	btrfs_log_put_delayed_items(inode, ins_list: &delayed_ins_list,
6713	del_list: &delayed_del_list);
6714	}
6715
6716	return ret;
6717	}
6718
6719	static int btrfs_log_all_parents(struct btrfs_trans_handle *trans,
6720	struct btrfs_inode *inode,
6721	struct btrfs_log_ctx *ctx)
6722	{
6723	struct btrfs_fs_info *fs_info = trans->fs_info;
6724	int ret;
6725	struct btrfs_path *path;
6726	struct btrfs_key key;
6727	struct btrfs_root *root = inode->root;
6728	const u64 ino = btrfs_ino(inode);
6729
6730	path = btrfs_alloc_path();
6731	if (!path)
6732	return -ENOMEM;
6733	path->skip_locking = 1;
6734	path->search_commit_root = 1;
6735
6736	key.objectid = ino;
6737	key.type = BTRFS_INODE_REF_KEY;
6738	key.offset = 0;
6739	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
6740	if (ret < 0)
6741	goto out;
6742
6743	while (true) {
6744	struct extent_buffer *leaf = path->nodes[0];
6745	int slot = path->slots[0];
6746	u32 cur_offset = 0;
6747	u32 item_size;
6748	unsigned long ptr;
6749
6750	if (slot >= btrfs_header_nritems(eb: leaf)) {
6751	ret = btrfs_next_leaf(root, path);
6752	if (ret < 0)
6753	goto out;
6754	else if (ret > 0)
6755	break;
6756	continue;
6757	}
6758
6759	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: slot);
6760	/* BTRFS_INODE_EXTREF_KEY is BTRFS_INODE_REF_KEY + 1 */
6761	if (key.objectid != ino || key.type > BTRFS_INODE_EXTREF_KEY)
6762	break;
6763
6764	item_size = btrfs_item_size(eb: leaf, slot);
6765	ptr = btrfs_item_ptr_offset(leaf, slot);
6766	while (cur_offset < item_size) {
6767	struct btrfs_key inode_key;
6768	struct inode *dir_inode;
6769
6770	inode_key.type = BTRFS_INODE_ITEM_KEY;
6771	inode_key.offset = 0;
6772
6773	if (key.type == BTRFS_INODE_EXTREF_KEY) {
6774	struct btrfs_inode_extref *extref;
6775
6776	extref = (struct btrfs_inode_extref *)
6777	(ptr + cur_offset);
6778	inode_key.objectid = btrfs_inode_extref_parent(
6779	eb: leaf, s: extref);
6780	cur_offset += sizeof(*extref);
6781	cur_offset += btrfs_inode_extref_name_len(eb: leaf,
6782	s: extref);
6783	} else {
6784	inode_key.objectid = key.offset;
6785	cur_offset = item_size;
6786	}
6787
6788	dir_inode = btrfs_iget(s: fs_info->sb, ino: inode_key.objectid,
6789	root);
6790	/*
6791	* If the parent inode was deleted, return an error to
6792	* fallback to a transaction commit. This is to prevent
6793	* getting an inode that was moved from one parent A to
6794	* a parent B, got its former parent A deleted and then
6795	* it got fsync'ed, from existing at both parents after
6796	* a log replay (and the old parent still existing).
6797	* Example:
6798	*
6799	* mkdir /mnt/A
6800	* mkdir /mnt/B
6801	* touch /mnt/B/bar
6802	* sync
6803	* mv /mnt/B/bar /mnt/A/bar
6804	* mv -T /mnt/A /mnt/B
6805	* fsync /mnt/B/bar
6806	* <power fail>
6807	*
6808	* If we ignore the old parent B which got deleted,
6809	* after a log replay we would have file bar linked
6810	* at both parents and the old parent B would still
6811	* exist.
6812	*/
6813	if (IS_ERR(ptr: dir_inode)) {
6814	ret = PTR_ERR(ptr: dir_inode);
6815	goto out;
6816	}
6817
6818	if (!need_log_inode(trans, inode: BTRFS_I(inode: dir_inode))) {
6819	btrfs_add_delayed_iput(inode: BTRFS_I(inode: dir_inode));
6820	continue;
6821	}
6822
6823	ctx->log_new_dentries = false;
6824	ret = btrfs_log_inode(trans, inode: BTRFS_I(inode: dir_inode),
6825	inode_only: LOG_INODE_ALL, ctx);
6826	if (!ret && ctx->log_new_dentries)
6827	ret = log_new_dir_dentries(trans,
6828	start_inode: BTRFS_I(inode: dir_inode), ctx);
6829	btrfs_add_delayed_iput(inode: BTRFS_I(inode: dir_inode));
6830	if (ret)
6831	goto out;
6832	}
6833	path->slots[0]++;
6834	}
6835	ret = 0;
6836	out:
6837	btrfs_free_path(p: path);
6838	return ret;
6839	}
6840
6841	static int log_new_ancestors(struct btrfs_trans_handle *trans,
6842	struct btrfs_root *root,
6843	struct btrfs_path *path,
6844	struct btrfs_log_ctx *ctx)
6845	{
6846	struct btrfs_key found_key;
6847
6848	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &found_key, nr: path->slots[0]);
6849
6850	while (true) {
6851	struct btrfs_fs_info *fs_info = root->fs_info;
6852	struct extent_buffer *leaf;
6853	int slot;
6854	struct btrfs_key search_key;
6855	struct inode *inode;
6856	u64 ino;
6857	int ret = 0;
6858
6859	btrfs_release_path(p: path);
6860
6861	ino = found_key.offset;
6862
6863	search_key.objectid = found_key.offset;
6864	search_key.type = BTRFS_INODE_ITEM_KEY;
6865	search_key.offset = 0;
6866	inode = btrfs_iget(s: fs_info->sb, ino, root);
6867	if (IS_ERR(ptr: inode))
6868	return PTR_ERR(ptr: inode);
6869
6870	if (BTRFS_I(inode)->generation >= trans->transid &&
6871	need_log_inode(trans, inode: BTRFS_I(inode)))
6872	ret = btrfs_log_inode(trans, inode: BTRFS_I(inode),
6873	inode_only: LOG_INODE_EXISTS, ctx);
6874	btrfs_add_delayed_iput(inode: BTRFS_I(inode));
6875	if (ret)
6876	return ret;
6877
6878	if (search_key.objectid == BTRFS_FIRST_FREE_OBJECTID)
6879	break;
6880
6881	search_key.type = BTRFS_INODE_REF_KEY;
6882	ret = btrfs_search_slot(NULL, root, key: &search_key, p: path, ins_len: 0, cow: 0);
6883	if (ret < 0)
6884	return ret;
6885
6886	leaf = path->nodes[0];
6887	slot = path->slots[0];
6888	if (slot >= btrfs_header_nritems(eb: leaf)) {
6889	ret = btrfs_next_leaf(root, path);
6890	if (ret < 0)
6891	return ret;
6892	else if (ret > 0)
6893	return -ENOENT;
6894	leaf = path->nodes[0];
6895	slot = path->slots[0];
6896	}
6897
6898	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &found_key, nr: slot);
6899	if (found_key.objectid != search_key.objectid ||
6900	found_key.type != BTRFS_INODE_REF_KEY)
6901	return -ENOENT;
6902	}
6903	return 0;
6904	}
6905
6906	static int log_new_ancestors_fast(struct btrfs_trans_handle *trans,
6907	struct btrfs_inode *inode,
6908	struct dentry *parent,
6909	struct btrfs_log_ctx *ctx)
6910	{
6911	struct btrfs_root *root = inode->root;
6912	struct dentry *old_parent = NULL;
6913	struct super_block *sb = inode->vfs_inode.i_sb;
6914	int ret = 0;
6915
6916	while (true) {
6917	if (!parent || d_really_is_negative(dentry: parent) ||
6918	sb != parent->d_sb)
6919	break;
6920
6921	inode = BTRFS_I(inode: d_inode(dentry: parent));
6922	if (root != inode->root)
6923	break;
6924
6925	if (inode->generation >= trans->transid &&
6926	need_log_inode(trans, inode)) {
6927	ret = btrfs_log_inode(trans, inode,
6928	inode_only: LOG_INODE_EXISTS, ctx);
6929	if (ret)
6930	break;
6931	}
6932	if (IS_ROOT(parent))
6933	break;
6934
6935	parent = dget_parent(dentry: parent);
6936	dput(old_parent);
6937	old_parent = parent;
6938	}
6939	dput(old_parent);
6940
6941	return ret;
6942	}
6943
6944	static int log_all_new_ancestors(struct btrfs_trans_handle *trans,
6945	struct btrfs_inode *inode,
6946	struct dentry *parent,
6947	struct btrfs_log_ctx *ctx)
6948	{
6949	struct btrfs_root *root = inode->root;
6950	const u64 ino = btrfs_ino(inode);
6951	struct btrfs_path *path;
6952	struct btrfs_key search_key;
6953	int ret;
6954
6955	/*
6956	* For a single hard link case, go through a fast path that does not
6957	* need to iterate the fs/subvolume tree.
6958	*/
6959	if (inode->vfs_inode.i_nlink < 2)
6960	return log_new_ancestors_fast(trans, inode, parent, ctx);
6961
6962	path = btrfs_alloc_path();
6963	if (!path)
6964	return -ENOMEM;
6965
6966	search_key.objectid = ino;
6967	search_key.type = BTRFS_INODE_REF_KEY;
6968	search_key.offset = 0;
6969	again:
6970	ret = btrfs_search_slot(NULL, root, key: &search_key, p: path, ins_len: 0, cow: 0);
6971	if (ret < 0)
6972	goto out;
6973	if (ret == 0)
6974	path->slots[0]++;
6975
6976	while (true) {
6977	struct extent_buffer *leaf = path->nodes[0];
6978	int slot = path->slots[0];
6979	struct btrfs_key found_key;
6980
6981	if (slot >= btrfs_header_nritems(eb: leaf)) {
6982	ret = btrfs_next_leaf(root, path);
6983	if (ret < 0)
6984	goto out;
6985	else if (ret > 0)
6986	break;
6987	continue;
6988	}
6989
6990	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &found_key, nr: slot);
6991	if (found_key.objectid != ino ||
6992	found_key.type > BTRFS_INODE_EXTREF_KEY)
6993	break;
6994
6995	/*
6996	* Don't deal with extended references because they are rare
6997	* cases and too complex to deal with (we would need to keep
6998	* track of which subitem we are processing for each item in
6999	* this loop, etc). So just return some error to fallback to
7000	* a transaction commit.
7001	*/
7002	if (found_key.type == BTRFS_INODE_EXTREF_KEY) {
7003	ret = -EMLINK;
7004	goto out;
7005	}
7006
7007	/*
7008	* Logging ancestors needs to do more searches on the fs/subvol
7009	* tree, so it releases the path as needed to avoid deadlocks.
7010	* Keep track of the last inode ref key and resume from that key
7011	* after logging all new ancestors for the current hard link.
7012	*/
7013	memcpy(&search_key, &found_key, sizeof(search_key));
7014
7015	ret = log_new_ancestors(trans, root, path, ctx);
7016	if (ret)
7017	goto out;
7018	btrfs_release_path(p: path);
7019	goto again;
7020	}
7021	ret = 0;
7022	out:
7023	btrfs_free_path(p: path);
7024	return ret;
7025	}
7026
7027	/*
7028	* helper function around btrfs_log_inode to make sure newly created
7029	* parent directories also end up in the log. A minimal inode and backref
7030	* only logging is done of any parent directories that are older than
7031	* the last committed transaction
7032	*/
7033	static int btrfs_log_inode_parent(struct btrfs_trans_handle *trans,
7034	struct btrfs_inode *inode,
7035	struct dentry *parent,
7036	int inode_only,
7037	struct btrfs_log_ctx *ctx)
7038	{
7039	struct btrfs_root *root = inode->root;
7040	struct btrfs_fs_info *fs_info = root->fs_info;
7041	int ret = 0;
7042	bool log_dentries = false;
7043
7044	if (btrfs_test_opt(fs_info, NOTREELOG)) {
7045	ret = BTRFS_LOG_FORCE_COMMIT;
7046	goto end_no_trans;
7047	}
7048
7049	if (btrfs_root_refs(s: &root->root_item) == 0) {
7050	ret = BTRFS_LOG_FORCE_COMMIT;
7051	goto end_no_trans;
7052	}
7053
7054	/*
7055	* Skip already logged inodes or inodes corresponding to tmpfiles
7056	* (since logging them is pointless, a link count of 0 means they
7057	* will never be accessible).
7058	*/
7059	if ((btrfs_inode_in_log(inode, generation: trans->transid) &&
7060	list_empty(head: &ctx->ordered_extents)) ||
7061	inode->vfs_inode.i_nlink == 0) {
7062	ret = BTRFS_NO_LOG_SYNC;
7063	goto end_no_trans;
7064	}
7065
7066	ret = start_log_trans(trans, root, ctx);
7067	if (ret)
7068	goto end_no_trans;
7069
7070	ret = btrfs_log_inode(trans, inode, inode_only, ctx);
7071	if (ret)
7072	goto end_trans;
7073
7074	/*
7075	* for regular files, if its inode is already on disk, we don't
7076	* have to worry about the parents at all. This is because
7077	* we can use the last_unlink_trans field to record renames
7078	* and other fun in this file.
7079	*/
7080	if (S_ISREG(inode->vfs_inode.i_mode) &&
7081	inode->generation < trans->transid &&
7082	inode->last_unlink_trans < trans->transid) {
7083	ret = 0;
7084	goto end_trans;
7085	}
7086
7087	if (S_ISDIR(inode->vfs_inode.i_mode) && ctx->log_new_dentries)
7088	log_dentries = true;
7089
7090	/*
7091	* On unlink we must make sure all our current and old parent directory
7092	* inodes are fully logged. This is to prevent leaving dangling
7093	* directory index entries in directories that were our parents but are
7094	* not anymore. Not doing this results in old parent directory being
7095	* impossible to delete after log replay (rmdir will always fail with
7096	* error -ENOTEMPTY).
7097	*
7098	* Example 1:
7099	*
7100	* mkdir testdir
7101	* touch testdir/foo
7102	* ln testdir/foo testdir/bar
7103	* sync
7104	* unlink testdir/bar
7105	* xfs_io -c fsync testdir/foo
7106	* <power failure>
7107	* mount fs, triggers log replay
7108	*
7109	* If we don't log the parent directory (testdir), after log replay the
7110	* directory still has an entry pointing to the file inode using the bar
7111	* name, but a matching BTRFS_INODE_[REF|EXTREF]_KEY does not exist and
7112	* the file inode has a link count of 1.
7113	*
7114	* Example 2:
7115	*
7116	* mkdir testdir
7117	* touch foo
7118	* ln foo testdir/foo2
7119	* ln foo testdir/foo3
7120	* sync
7121	* unlink testdir/foo3
7122	* xfs_io -c fsync foo
7123	* <power failure>
7124	* mount fs, triggers log replay
7125	*
7126	* Similar as the first example, after log replay the parent directory
7127	* testdir still has an entry pointing to the inode file with name foo3
7128	* but the file inode does not have a matching BTRFS_INODE_REF_KEY item
7129	* and has a link count of 2.
7130	*/
7131	if (inode->last_unlink_trans >= trans->transid) {
7132	ret = btrfs_log_all_parents(trans, inode, ctx);
7133	if (ret)
7134	goto end_trans;
7135	}
7136
7137	ret = log_all_new_ancestors(trans, inode, parent, ctx);
7138	if (ret)
7139	goto end_trans;
7140
7141	if (log_dentries)
7142	ret = log_new_dir_dentries(trans, start_inode: inode, ctx);
7143	else
7144	ret = 0;
7145	end_trans:
7146	if (ret < 0) {
7147	btrfs_set_log_full_commit(trans);
7148	ret = BTRFS_LOG_FORCE_COMMIT;
7149	}
7150
7151	if (ret)
7152	btrfs_remove_log_ctx(root, ctx);
7153	btrfs_end_log_trans(root);
7154	end_no_trans:
7155	return ret;
7156	}
7157
7158	/*
7159	* it is not safe to log dentry if the chunk root has added new
7160	* chunks. This returns 0 if the dentry was logged, and 1 otherwise.
7161	* If this returns 1, you must commit the transaction to safely get your
7162	* data on disk.
7163	*/
7164	int btrfs_log_dentry_safe(struct btrfs_trans_handle *trans,
7165	struct dentry *dentry,
7166	struct btrfs_log_ctx *ctx)
7167	{
7168	struct dentry *parent = dget_parent(dentry);
7169	int ret;
7170
7171	ret = btrfs_log_inode_parent(trans, inode: BTRFS_I(inode: d_inode(dentry)), parent,
7172	inode_only: LOG_INODE_ALL, ctx);
7173	dput(parent);
7174
7175	return ret;
7176	}
7177
7178	/*
7179	* should be called during mount to recover any replay any log trees
7180	* from the FS
7181	*/
7182	int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
7183	{
7184	int ret;
7185	struct btrfs_path *path;
7186	struct btrfs_trans_handle *trans;
7187	struct btrfs_key key;
7188	struct btrfs_key found_key;
7189	struct btrfs_root *log;
7190	struct btrfs_fs_info *fs_info = log_root_tree->fs_info;
7191	struct walk_control wc = {
7192	.process_func = process_one_buffer,
7193	.stage = LOG_WALK_PIN_ONLY,
7194	};
7195
7196	path = btrfs_alloc_path();
7197	if (!path)
7198	return -ENOMEM;
7199
7200	set_bit(nr: BTRFS_FS_LOG_RECOVERING, addr: &fs_info->flags);
7201
7202	trans = btrfs_start_transaction(root: fs_info->tree_root, num_items: 0);
7203	if (IS_ERR(ptr: trans)) {
7204	ret = PTR_ERR(ptr: trans);
7205	goto error;
7206	}
7207
7208	wc.trans = trans;
7209	wc.pin = 1;
7210
7211	ret = walk_log_tree(trans, log: log_root_tree, wc: &wc);
7212	if (ret) {
7213	btrfs_abort_transaction(trans, ret);
7214	goto error;
7215	}
7216
7217	again:
7218	key.objectid = BTRFS_TREE_LOG_OBJECTID;
7219	key.offset = (u64)-1;
7220	key.type = BTRFS_ROOT_ITEM_KEY;
7221
7222	while (1) {
7223	ret = btrfs_search_slot(NULL, root: log_root_tree, key: &key, p: path, ins_len: 0, cow: 0);
7224
7225	if (ret < 0) {
7226	btrfs_abort_transaction(trans, ret);
7227	goto error;
7228	}
7229	if (ret > 0) {
7230	if (path->slots[0] == 0)
7231	break;
7232	path->slots[0]--;
7233	}
7234	btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &found_key,
7235	nr: path->slots[0]);
7236	btrfs_release_path(p: path);
7237	if (found_key.objectid != BTRFS_TREE_LOG_OBJECTID)
7238	break;
7239
7240	log = btrfs_read_tree_root(tree_root: log_root_tree, key: &found_key);
7241	if (IS_ERR(ptr: log)) {
7242	ret = PTR_ERR(ptr: log);
7243	btrfs_abort_transaction(trans, ret);
7244	goto error;
7245	}
7246
7247	wc.replay_dest = btrfs_get_fs_root(fs_info, objectid: found_key.offset,
7248	check_ref: true);
7249	if (IS_ERR(ptr: wc.replay_dest)) {
7250	ret = PTR_ERR(ptr: wc.replay_dest);
7251
7252	/*
7253	* We didn't find the subvol, likely because it was
7254	* deleted. This is ok, simply skip this log and go to
7255	* the next one.
7256	*
7257	* We need to exclude the root because we can't have
7258	* other log replays overwriting this log as we'll read
7259	* it back in a few more times. This will keep our
7260	* block from being modified, and we'll just bail for
7261	* each subsequent pass.
7262	*/
7263	if (ret == -ENOENT)
7264	ret = btrfs_pin_extent_for_log_replay(trans, eb: log->node);
7265	btrfs_put_root(root: log);
7266
7267	if (!ret)
7268	goto next;
7269	btrfs_abort_transaction(trans, ret);
7270	goto error;
7271	}
7272
7273	wc.replay_dest->log_root = log;
7274	ret = btrfs_record_root_in_trans(trans, root: wc.replay_dest);
7275	if (ret)
7276	/* The loop needs to continue due to the root refs */
7277	btrfs_abort_transaction(trans, ret);
7278	else
7279	ret = walk_log_tree(trans, log, wc: &wc);
7280
7281	if (!ret && wc.stage == LOG_WALK_REPLAY_ALL) {
7282	ret = fixup_inode_link_counts(trans, root: wc.replay_dest,
7283	path);
7284	if (ret)
7285	btrfs_abort_transaction(trans, ret);
7286	}
7287
7288	if (!ret && wc.stage == LOG_WALK_REPLAY_ALL) {
7289	struct btrfs_root *root = wc.replay_dest;
7290
7291	btrfs_release_path(p: path);
7292
7293	/*
7294	* We have just replayed everything, and the highest
7295	* objectid of fs roots probably has changed in case
7296	* some inode_item's got replayed.
7297	*
7298	* root->objectid_mutex is not acquired as log replay
7299	* could only happen during mount.
7300	*/
7301	ret = btrfs_init_root_free_objectid(root);
7302	if (ret)
7303	btrfs_abort_transaction(trans, ret);
7304	}
7305
7306	wc.replay_dest->log_root = NULL;
7307	btrfs_put_root(root: wc.replay_dest);
7308	btrfs_put_root(root: log);
7309
7310	if (ret)
7311	goto error;
7312	next:
7313	if (found_key.offset == 0)
7314	break;
7315	key.offset = found_key.offset - 1;
7316	}
7317	btrfs_release_path(p: path);
7318
7319	/* step one is to pin it all, step two is to replay just inodes */
7320	if (wc.pin) {
7321	wc.pin = 0;
7322	wc.process_func = replay_one_buffer;
7323	wc.stage = LOG_WALK_REPLAY_INODES;
7324	goto again;
7325	}
7326	/* step three is to replay everything */
7327	if (wc.stage < LOG_WALK_REPLAY_ALL) {
7328	wc.stage++;
7329	goto again;
7330	}
7331
7332	btrfs_free_path(p: path);
7333
7334	/* step 4: commit the transaction, which also unpins the blocks */
7335	ret = btrfs_commit_transaction(trans);
7336	if (ret)
7337	return ret;
7338
7339	log_root_tree->log_root = NULL;
7340	clear_bit(nr: BTRFS_FS_LOG_RECOVERING, addr: &fs_info->flags);
7341	btrfs_put_root(root: log_root_tree);
7342
7343	return 0;
7344	error:
7345	if (wc.trans)
7346	btrfs_end_transaction(trans: wc.trans);
7347	clear_bit(nr: BTRFS_FS_LOG_RECOVERING, addr: &fs_info->flags);
7348	btrfs_free_path(p: path);
7349	return ret;
7350	}
7351
7352	/*
7353	* there are some corner cases where we want to force a full
7354	* commit instead of allowing a directory to be logged.
7355	*
7356	* They revolve around files there were unlinked from the directory, and
7357	* this function updates the parent directory so that a full commit is
7358	* properly done if it is fsync'd later after the unlinks are done.
7359	*
7360	* Must be called before the unlink operations (updates to the subvolume tree,
7361	* inodes, etc) are done.
7362	*/
7363	void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans,
7364	struct btrfs_inode *dir, struct btrfs_inode *inode,
7365	bool for_rename)
7366	{
7367	/*
7368	* when we're logging a file, if it hasn't been renamed
7369	* or unlinked, and its inode is fully committed on disk,
7370	* we don't have to worry about walking up the directory chain
7371	* to log its parents.
7372	*
7373	* So, we use the last_unlink_trans field to put this transid
7374	* into the file. When the file is logged we check it and
7375	* don't log the parents if the file is fully on disk.
7376	*/
7377	mutex_lock(&inode->log_mutex);
7378	inode->last_unlink_trans = trans->transid;
7379	mutex_unlock(lock: &inode->log_mutex);
7380
7381	if (!for_rename)
7382	return;
7383
7384	/*
7385	* If this directory was already logged, any new names will be logged
7386	* with btrfs_log_new_name() and old names will be deleted from the log
7387	* tree with btrfs_del_dir_entries_in_log() or with
7388	* btrfs_del_inode_ref_in_log().
7389	*/
7390	if (inode_logged(trans, inode: dir, NULL) == 1)
7391	return;
7392
7393	/*
7394	* If the inode we're about to unlink was logged before, the log will be
7395	* properly updated with the new name with btrfs_log_new_name() and the
7396	* old name removed with btrfs_del_dir_entries_in_log() or with
7397	* btrfs_del_inode_ref_in_log().
7398	*/
7399	if (inode_logged(trans, inode, NULL) == 1)
7400	return;
7401
7402	/*
7403	* when renaming files across directories, if the directory
7404	* there we're unlinking from gets fsync'd later on, there's
7405	* no way to find the destination directory later and fsync it
7406	* properly. So, we have to be conservative and force commits
7407	* so the new name gets discovered.
7408	*/
7409	mutex_lock(&dir->log_mutex);
7410	dir->last_unlink_trans = trans->transid;
7411	mutex_unlock(lock: &dir->log_mutex);
7412	}
7413
7414	/*
7415	* Make sure that if someone attempts to fsync the parent directory of a deleted
7416	* snapshot, it ends up triggering a transaction commit. This is to guarantee
7417	* that after replaying the log tree of the parent directory's root we will not
7418	* see the snapshot anymore and at log replay time we will not see any log tree
7419	* corresponding to the deleted snapshot's root, which could lead to replaying
7420	* it after replaying the log tree of the parent directory (which would replay
7421	* the snapshot delete operation).
7422	*
7423	* Must be called before the actual snapshot destroy operation (updates to the
7424	* parent root and tree of tree roots trees, etc) are done.
7425	*/
7426	void btrfs_record_snapshot_destroy(struct btrfs_trans_handle *trans,
7427	struct btrfs_inode *dir)
7428	{
7429	mutex_lock(&dir->log_mutex);
7430	dir->last_unlink_trans = trans->transid;
7431	mutex_unlock(lock: &dir->log_mutex);
7432	}
7433
7434	/*
7435	* Update the log after adding a new name for an inode.
7436	*
7437	* @trans: Transaction handle.
7438	* @old_dentry: The dentry associated with the old name and the old
7439	* parent directory.
7440	* @old_dir: The inode of the previous parent directory for the case
7441	* of a rename. For a link operation, it must be NULL.
7442	* @old_dir_index: The index number associated with the old name, meaningful
7443	* only for rename operations (when @old_dir is not NULL).
7444	* Ignored for link operations.
7445	* @parent: The dentry associated with the directory under which the
7446	* new name is located.
7447	*
7448	* Call this after adding a new name for an inode, as a result of a link or
7449	* rename operation, and it will properly update the log to reflect the new name.
7450	*/
7451	void btrfs_log_new_name(struct btrfs_trans_handle *trans,
7452	struct dentry *old_dentry, struct btrfs_inode *old_dir,
7453	u64 old_dir_index, struct dentry *parent)
7454	{
7455	struct btrfs_inode *inode = BTRFS_I(inode: d_inode(dentry: old_dentry));
7456	struct btrfs_root *root = inode->root;
7457	struct btrfs_log_ctx ctx;
7458	bool log_pinned = false;
7459	int ret;
7460
7461	/*
7462	* this will force the logging code to walk the dentry chain
7463	* up for the file
7464	*/
7465	if (!S_ISDIR(inode->vfs_inode.i_mode))
7466	inode->last_unlink_trans = trans->transid;
7467
7468	/*
7469	* if this inode hasn't been logged and directory we're renaming it
7470	* from hasn't been logged, we don't need to log it
7471	*/
7472	ret = inode_logged(trans, inode, NULL);
7473	if (ret < 0) {
7474	goto out;
7475	} else if (ret == 0) {
7476	if (!old_dir)
7477	return;
7478	/*
7479	* If the inode was not logged and we are doing a rename (old_dir is not
7480	* NULL), check if old_dir was logged - if it was not we can return and
7481	* do nothing.
7482	*/
7483	ret = inode_logged(trans, inode: old_dir, NULL);
7484	if (ret < 0)
7485	goto out;
7486	else if (ret == 0)
7487	return;
7488	}
7489	ret = 0;
7490
7491	/*
7492	* If we are doing a rename (old_dir is not NULL) from a directory that
7493	* was previously logged, make sure that on log replay we get the old
7494	* dir entry deleted. This is needed because we will also log the new
7495	* name of the renamed inode, so we need to make sure that after log
7496	* replay we don't end up with both the new and old dir entries existing.
7497	*/
7498	if (old_dir && old_dir->logged_trans == trans->transid) {
7499	struct btrfs_root *log = old_dir->root->log_root;
7500	struct btrfs_path *path;
7501	struct fscrypt_name fname;
7502
7503	ASSERT(old_dir_index >= BTRFS_DIR_START_INDEX);
7504
7505	ret = fscrypt_setup_filename(inode: &old_dir->vfs_inode,
7506	iname: &old_dentry->d_name, lookup: 0, fname: &fname);
7507	if (ret)
7508	goto out;
7509	/*
7510	* We have two inodes to update in the log, the old directory and
7511	* the inode that got renamed, so we must pin the log to prevent
7512	* anyone from syncing the log until we have updated both inodes
7513	* in the log.
7514	*/
7515	ret = join_running_log_trans(root);
7516	/*
7517	* At least one of the inodes was logged before, so this should
7518	* not fail, but if it does, it's not serious, just bail out and
7519	* mark the log for a full commit.
7520	*/
7521	if (WARN_ON_ONCE(ret < 0)) {
7522	fscrypt_free_filename(fname: &fname);
7523	goto out;
7524	}
7525
7526	log_pinned = true;
7527
7528	path = btrfs_alloc_path();
7529	if (!path) {
7530	ret = -ENOMEM;
7531	fscrypt_free_filename(fname: &fname);
7532	goto out;
7533	}
7534
7535	/*
7536	* Other concurrent task might be logging the old directory,
7537	* as it can be triggered when logging other inode that had or
7538	* still has a dentry in the old directory. We lock the old
7539	* directory's log_mutex to ensure the deletion of the old
7540	* name is persisted, because during directory logging we
7541	* delete all BTRFS_DIR_LOG_INDEX_KEY keys and the deletion of
7542	* the old name's dir index item is in the delayed items, so
7543	* it could be missed by an in progress directory logging.
7544	*/
7545	mutex_lock(&old_dir->log_mutex);
7546	ret = del_logged_dentry(trans, log, path, dir_ino: btrfs_ino(inode: old_dir),
7547	name: &fname.disk_name, index: old_dir_index);
7548	if (ret > 0) {
7549	/*
7550	* The dentry does not exist in the log, so record its
7551	* deletion.
7552	*/
7553	btrfs_release_path(p: path);
7554	ret = insert_dir_log_key(trans, log, path,
7555	dirid: btrfs_ino(inode: old_dir),
7556	first_offset: old_dir_index, last_offset: old_dir_index);
7557	}
7558	mutex_unlock(lock: &old_dir->log_mutex);
7559
7560	btrfs_free_path(p: path);
7561	fscrypt_free_filename(fname: &fname);
7562	if (ret < 0)
7563	goto out;
7564	}
7565
7566	btrfs_init_log_ctx(ctx: &ctx, inode: &inode->vfs_inode);
7567	ctx.logging_new_name = true;
7568	btrfs_init_log_ctx_scratch_eb(ctx: &ctx);
7569	/*
7570	* We don't care about the return value. If we fail to log the new name
7571	* then we know the next attempt to sync the log will fallback to a full
7572	* transaction commit (due to a call to btrfs_set_log_full_commit()), so
7573	* we don't need to worry about getting a log committed that has an
7574	* inconsistent state after a rename operation.
7575	*/
7576	btrfs_log_inode_parent(trans, inode, parent, inode_only: LOG_INODE_EXISTS, ctx: &ctx);
7577	free_extent_buffer(eb: ctx.scratch_eb);
7578	ASSERT(list_empty(&ctx.conflict_inodes));
7579	out:
7580	/*
7581	* If an error happened mark the log for a full commit because it's not
7582	* consistent and up to date or we couldn't find out if one of the
7583	* inodes was logged before in this transaction. Do it before unpinning
7584	* the log, to avoid any races with someone else trying to commit it.
7585	*/
7586	if (ret < 0)
7587	btrfs_set_log_full_commit(trans);
7588	if (log_pinned)
7589	btrfs_end_log_trans(root);
7590	}
7591
7592