1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/ext4/extents_status.c
4 *
5 * Written by Yongqiang Yang <xiaoqiangnk@gmail.com>
6 * Modified by
7 * Allison Henderson <achender@linux.vnet.ibm.com>
8 * Hugh Dickins <hughd@google.com>
9 * Zheng Liu <wenqing.lz@taobao.com>
10 *
11 * Ext4 extents status tree core functions.
12 */
13#include <linux/list_sort.h>
14#include <linux/proc_fs.h>
15#include <linux/seq_file.h>
16#include "ext4.h"
17
18#include <trace/events/ext4.h>
19
20/*
21 * According to previous discussion in Ext4 Developer Workshop, we
22 * will introduce a new structure called io tree to track all extent
23 * status in order to solve some problems that we have met
24 * (e.g. Reservation space warning), and provide extent-level locking.
25 * Delay extent tree is the first step to achieve this goal. It is
26 * original built by Yongqiang Yang. At that time it is called delay
27 * extent tree, whose goal is only track delayed extents in memory to
28 * simplify the implementation of fiemap and bigalloc, and introduce
29 * lseek SEEK_DATA/SEEK_HOLE support. That is why it is still called
30 * delay extent tree at the first commit. But for better understand
31 * what it does, it has been rename to extent status tree.
32 *
33 * Step1:
34 * Currently the first step has been done. All delayed extents are
35 * tracked in the tree. It maintains the delayed extent when a delayed
36 * allocation is issued, and the delayed extent is written out or
37 * invalidated. Therefore the implementation of fiemap and bigalloc
38 * are simplified, and SEEK_DATA/SEEK_HOLE are introduced.
39 *
40 * The following comment describes the implemenmtation of extent
41 * status tree and future works.
42 *
43 * Step2:
44 * In this step all extent status are tracked by extent status tree.
45 * Thus, we can first try to lookup a block mapping in this tree before
46 * finding it in extent tree. Hence, single extent cache can be removed
47 * because extent status tree can do a better job. Extents in status
48 * tree are loaded on-demand. Therefore, the extent status tree may not
49 * contain all of the extents in a file. Meanwhile we define a shrinker
50 * to reclaim memory from extent status tree because fragmented extent
51 * tree will make status tree cost too much memory. written/unwritten/-
52 * hole extents in the tree will be reclaimed by this shrinker when we
53 * are under high memory pressure. Delayed extents will not be
54 * reclimed because fiemap, bigalloc, and seek_data/hole need it.
55 */
56
57/*
58 * Extent status tree implementation for ext4.
59 *
60 *
61 * ==========================================================================
62 * Extent status tree tracks all extent status.
63 *
64 * 1. Why we need to implement extent status tree?
65 *
66 * Without extent status tree, ext4 identifies a delayed extent by looking
67 * up page cache, this has several deficiencies - complicated, buggy,
68 * and inefficient code.
69 *
70 * FIEMAP, SEEK_HOLE/DATA, bigalloc, and writeout all need to know if a
71 * block or a range of blocks are belonged to a delayed extent.
72 *
73 * Let us have a look at how they do without extent status tree.
74 * -- FIEMAP
75 * FIEMAP looks up page cache to identify delayed allocations from holes.
76 *
77 * -- SEEK_HOLE/DATA
78 * SEEK_HOLE/DATA has the same problem as FIEMAP.
79 *
80 * -- bigalloc
81 * bigalloc looks up page cache to figure out if a block is
82 * already under delayed allocation or not to determine whether
83 * quota reserving is needed for the cluster.
84 *
85 * -- writeout
86 * Writeout looks up whole page cache to see if a buffer is
87 * mapped, If there are not very many delayed buffers, then it is
88 * time consuming.
89 *
90 * With extent status tree implementation, FIEMAP, SEEK_HOLE/DATA,
91 * bigalloc and writeout can figure out if a block or a range of
92 * blocks is under delayed allocation(belonged to a delayed extent) or
93 * not by searching the extent tree.
94 *
95 *
96 * ==========================================================================
97 * 2. Ext4 extent status tree impelmentation
98 *
99 * -- extent
100 * A extent is a range of blocks which are contiguous logically and
101 * physically. Unlike extent in extent tree, this extent in ext4 is
102 * a in-memory struct, there is no corresponding on-disk data. There
103 * is no limit on length of extent, so an extent can contain as many
104 * blocks as they are contiguous logically and physically.
105 *
106 * -- extent status tree
107 * Every inode has an extent status tree and all allocation blocks
108 * are added to the tree with different status. The extent in the
109 * tree are ordered by logical block no.
110 *
111 * -- operations on a extent status tree
112 * There are three important operations on a delayed extent tree: find
113 * next extent, adding a extent(a range of blocks) and removing a extent.
114 *
115 * -- race on a extent status tree
116 * Extent status tree is protected by inode->i_es_lock.
117 *
118 * -- memory consumption
119 * Fragmented extent tree will make extent status tree cost too much
120 * memory. Hence, we will reclaim written/unwritten/hole extents from
121 * the tree under a heavy memory pressure.
122 *
123 * ==========================================================================
124 * 3. Assurance of Ext4 extent status tree consistency
125 *
126 * When mapping blocks, Ext4 queries the extent status tree first and should
127 * always trusts that the extent status tree is consistent and up to date.
128 * Therefore, it is important to adheres to the following rules when createing,
129 * modifying and removing extents.
130 *
131 * 1. Besides fastcommit replay, when Ext4 creates or queries block mappings,
132 * the extent information should always be processed through the extent
133 * status tree instead of being organized manually through the on-disk
134 * extent tree.
135 *
136 * 2. When updating the extent tree, Ext4 should acquire the i_data_sem
137 * exclusively and update the extent status tree atomically. If the extents
138 * to be modified are large enough to exceed the range that a single
139 * i_data_sem can process (as ext4_datasem_ensure_credits() may drop
140 * i_data_sem to restart a transaction), it must (e.g. as ext4_punch_hole()
141 * does):
142 *
143 * a) Hold the i_rwsem and invalidate_lock exclusively. This ensures
144 * exclusion against page faults, as well as reads and writes that may
145 * concurrently modify the extent status tree.
146 * b) Evict all page cache in the affected range and recommend rebuilding
147 * or dropping the extent status tree after modifying the on-disk
148 * extent tree. This ensures exclusion against concurrent writebacks
149 * that do not hold those locks but only holds a folio lock.
150 *
151 * 3. Based on the rules above, when querying block mappings, Ext4 should at
152 * least hold the i_rwsem or invalidate_lock or folio lock(s) for the
153 * specified querying range.
154 *
155 * ==========================================================================
156 * 4. Performance analysis
157 *
158 * -- overhead
159 * 1. There is a cache extent for write access, so if writes are
160 * not very random, adding space operaions are in O(1) time.
161 *
162 * -- gain
163 * 2. Code is much simpler, more readable, more maintainable and
164 * more efficient.
165 *
166 *
167 * ==========================================================================
168 * 5. TODO list
169 *
170 * -- Refactor delayed space reservation
171 *
172 * -- Extent-level locking
173 */
174
175static struct kmem_cache *ext4_es_cachep;
176static struct kmem_cache *ext4_pending_cachep;
177
178static int __es_insert_extent(struct inode *inode, struct extent_status *newes,
179 struct extent_status *prealloc);
180static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
181 ext4_lblk_t end, int *reserved,
182 struct extent_status *prealloc);
183static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan);
184static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan,
185 struct ext4_inode_info *locked_ei);
186static int __revise_pending(struct inode *inode, ext4_lblk_t lblk,
187 ext4_lblk_t len,
188 struct pending_reservation **prealloc);
189
190int __init ext4_init_es(void)
191{
192 ext4_es_cachep = KMEM_CACHE(extent_status, SLAB_RECLAIM_ACCOUNT);
193 if (ext4_es_cachep == NULL)
194 return -ENOMEM;
195 return 0;
196}
197
198void ext4_exit_es(void)
199{
200 kmem_cache_destroy(s: ext4_es_cachep);
201}
202
203void ext4_es_init_tree(struct ext4_es_tree *tree)
204{
205 tree->root = RB_ROOT;
206 tree->cache_es = NULL;
207}
208
209#ifdef ES_DEBUG__
210static void ext4_es_print_tree(struct inode *inode)
211{
212 struct ext4_es_tree *tree;
213 struct rb_node *node;
214
215 printk(KERN_DEBUG "status extents for inode %lu:", inode->i_ino);
216 tree = &EXT4_I(inode)->i_es_tree;
217 node = rb_first(&tree->root);
218 while (node) {
219 struct extent_status *es;
220 es = rb_entry(node, struct extent_status, rb_node);
221 printk(KERN_DEBUG " [%u/%u) %llu %x",
222 es->es_lblk, es->es_len,
223 ext4_es_pblock(es), ext4_es_status(es));
224 node = rb_next(node);
225 }
226 printk(KERN_DEBUG "\n");
227}
228#else
229#define ext4_es_print_tree(inode)
230#endif
231
232static inline ext4_lblk_t ext4_es_end(struct extent_status *es)
233{
234 BUG_ON(es->es_lblk + es->es_len < es->es_lblk);
235 return es->es_lblk + es->es_len - 1;
236}
237
238static inline void ext4_es_inc_seq(struct inode *inode)
239{
240 struct ext4_inode_info *ei = EXT4_I(inode);
241
242 WRITE_ONCE(ei->i_es_seq, ei->i_es_seq + 1);
243}
244
245/*
246 * search through the tree for an delayed extent with a given offset. If
247 * it can't be found, try to find next extent.
248 */
249static struct extent_status *__es_tree_search(struct rb_root *root,
250 ext4_lblk_t lblk)
251{
252 struct rb_node *node = root->rb_node;
253 struct extent_status *es = NULL;
254
255 while (node) {
256 es = rb_entry(node, struct extent_status, rb_node);
257 if (lblk < es->es_lblk)
258 node = node->rb_left;
259 else if (lblk > ext4_es_end(es))
260 node = node->rb_right;
261 else
262 return es;
263 }
264
265 if (es && lblk < es->es_lblk)
266 return es;
267
268 if (es && lblk > ext4_es_end(es)) {
269 node = rb_next(&es->rb_node);
270 return node ? rb_entry(node, struct extent_status, rb_node) :
271 NULL;
272 }
273
274 return NULL;
275}
276
277/*
278 * ext4_es_find_extent_range - find extent with specified status within block
279 * range or next extent following block range in
280 * extents status tree
281 *
282 * @inode - file containing the range
283 * @matching_fn - pointer to function that matches extents with desired status
284 * @lblk - logical block defining start of range
285 * @end - logical block defining end of range
286 * @es - extent found, if any
287 *
288 * Find the first extent within the block range specified by @lblk and @end
289 * in the extents status tree that satisfies @matching_fn. If a match
290 * is found, it's returned in @es. If not, and a matching extent is found
291 * beyond the block range, it's returned in @es. If no match is found, an
292 * extent is returned in @es whose es_lblk, es_len, and es_pblk components
293 * are 0.
294 */
295static void __es_find_extent_range(struct inode *inode,
296 int (*matching_fn)(struct extent_status *es),
297 ext4_lblk_t lblk, ext4_lblk_t end,
298 struct extent_status *es)
299{
300 struct ext4_es_tree *tree = NULL;
301 struct extent_status *es1 = NULL;
302 struct rb_node *node;
303
304 WARN_ON(es == NULL);
305 WARN_ON(end < lblk);
306
307 tree = &EXT4_I(inode)->i_es_tree;
308
309 /* see if the extent has been cached */
310 es->es_lblk = es->es_len = es->es_pblk = 0;
311 es1 = READ_ONCE(tree->cache_es);
312 if (es1 && in_range(lblk, es1->es_lblk, es1->es_len)) {
313 es_debug("%u cached by [%u/%u) %llu %x\n",
314 lblk, es1->es_lblk, es1->es_len,
315 ext4_es_pblock(es1), ext4_es_status(es1));
316 goto out;
317 }
318
319 es1 = __es_tree_search(root: &tree->root, lblk);
320
321out:
322 if (es1 && !matching_fn(es1)) {
323 while ((node = rb_next(&es1->rb_node)) != NULL) {
324 es1 = rb_entry(node, struct extent_status, rb_node);
325 if (es1->es_lblk > end) {
326 es1 = NULL;
327 break;
328 }
329 if (matching_fn(es1))
330 break;
331 }
332 }
333
334 if (es1 && matching_fn(es1)) {
335 WRITE_ONCE(tree->cache_es, es1);
336 es->es_lblk = es1->es_lblk;
337 es->es_len = es1->es_len;
338 es->es_pblk = es1->es_pblk;
339 }
340
341}
342
343/*
344 * Locking for __es_find_extent_range() for external use
345 */
346void ext4_es_find_extent_range(struct inode *inode,
347 int (*matching_fn)(struct extent_status *es),
348 ext4_lblk_t lblk, ext4_lblk_t end,
349 struct extent_status *es)
350{
351 es->es_lblk = es->es_len = es->es_pblk = 0;
352
353 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
354 return;
355
356 trace_ext4_es_find_extent_range_enter(inode, lblk);
357
358 read_lock(&EXT4_I(inode)->i_es_lock);
359 __es_find_extent_range(inode, matching_fn, lblk, end, es);
360 read_unlock(&EXT4_I(inode)->i_es_lock);
361
362 trace_ext4_es_find_extent_range_exit(inode, es);
363}
364
365/*
366 * __es_scan_range - search block range for block with specified status
367 * in extents status tree
368 *
369 * @inode - file containing the range
370 * @matching_fn - pointer to function that matches extents with desired status
371 * @lblk - logical block defining start of range
372 * @end - logical block defining end of range
373 *
374 * Returns true if at least one block in the specified block range satisfies
375 * the criterion specified by @matching_fn, and false if not. If at least
376 * one extent has the specified status, then there is at least one block
377 * in the cluster with that status. Should only be called by code that has
378 * taken i_es_lock.
379 */
380static bool __es_scan_range(struct inode *inode,
381 int (*matching_fn)(struct extent_status *es),
382 ext4_lblk_t start, ext4_lblk_t end)
383{
384 struct extent_status es;
385
386 __es_find_extent_range(inode, matching_fn, lblk: start, end, es: &es);
387 if (es.es_len == 0)
388 return false; /* no matching extent in the tree */
389 else if (es.es_lblk <= start &&
390 start < es.es_lblk + es.es_len)
391 return true;
392 else if (start <= es.es_lblk && es.es_lblk <= end)
393 return true;
394 else
395 return false;
396}
397/*
398 * Locking for __es_scan_range() for external use
399 */
400bool ext4_es_scan_range(struct inode *inode,
401 int (*matching_fn)(struct extent_status *es),
402 ext4_lblk_t lblk, ext4_lblk_t end)
403{
404 bool ret;
405
406 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
407 return false;
408
409 read_lock(&EXT4_I(inode)->i_es_lock);
410 ret = __es_scan_range(inode, matching_fn, start: lblk, end);
411 read_unlock(&EXT4_I(inode)->i_es_lock);
412
413 return ret;
414}
415
416/*
417 * __es_scan_clu - search cluster for block with specified status in
418 * extents status tree
419 *
420 * @inode - file containing the cluster
421 * @matching_fn - pointer to function that matches extents with desired status
422 * @lblk - logical block in cluster to be searched
423 *
424 * Returns true if at least one extent in the cluster containing @lblk
425 * satisfies the criterion specified by @matching_fn, and false if not. If at
426 * least one extent has the specified status, then there is at least one block
427 * in the cluster with that status. Should only be called by code that has
428 * taken i_es_lock.
429 */
430static bool __es_scan_clu(struct inode *inode,
431 int (*matching_fn)(struct extent_status *es),
432 ext4_lblk_t lblk)
433{
434 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
435 ext4_lblk_t lblk_start, lblk_end;
436
437 lblk_start = EXT4_LBLK_CMASK(sbi, lblk);
438 lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
439
440 return __es_scan_range(inode, matching_fn, start: lblk_start, end: lblk_end);
441}
442
443/*
444 * Locking for __es_scan_clu() for external use
445 */
446bool ext4_es_scan_clu(struct inode *inode,
447 int (*matching_fn)(struct extent_status *es),
448 ext4_lblk_t lblk)
449{
450 bool ret;
451
452 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
453 return false;
454
455 read_lock(&EXT4_I(inode)->i_es_lock);
456 ret = __es_scan_clu(inode, matching_fn, lblk);
457 read_unlock(&EXT4_I(inode)->i_es_lock);
458
459 return ret;
460}
461
462static void ext4_es_list_add(struct inode *inode)
463{
464 struct ext4_inode_info *ei = EXT4_I(inode);
465 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
466
467 if (!list_empty(head: &ei->i_es_list))
468 return;
469
470 spin_lock(lock: &sbi->s_es_lock);
471 if (list_empty(head: &ei->i_es_list)) {
472 list_add_tail(new: &ei->i_es_list, head: &sbi->s_es_list);
473 sbi->s_es_nr_inode++;
474 }
475 spin_unlock(lock: &sbi->s_es_lock);
476}
477
478static void ext4_es_list_del(struct inode *inode)
479{
480 struct ext4_inode_info *ei = EXT4_I(inode);
481 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
482
483 spin_lock(lock: &sbi->s_es_lock);
484 if (!list_empty(head: &ei->i_es_list)) {
485 list_del_init(entry: &ei->i_es_list);
486 sbi->s_es_nr_inode--;
487 WARN_ON_ONCE(sbi->s_es_nr_inode < 0);
488 }
489 spin_unlock(lock: &sbi->s_es_lock);
490}
491
492static inline struct pending_reservation *__alloc_pending(bool nofail)
493{
494 if (!nofail)
495 return kmem_cache_alloc(ext4_pending_cachep, GFP_ATOMIC);
496
497 return kmem_cache_zalloc(ext4_pending_cachep, GFP_KERNEL | __GFP_NOFAIL);
498}
499
500static inline void __free_pending(struct pending_reservation *pr)
501{
502 kmem_cache_free(s: ext4_pending_cachep, objp: pr);
503}
504
505/*
506 * Returns true if we cannot fail to allocate memory for this extent_status
507 * entry and cannot reclaim it until its status changes.
508 */
509static inline bool ext4_es_must_keep(struct extent_status *es)
510{
511 /* fiemap, bigalloc, and seek_data/hole need to use it. */
512 if (ext4_es_is_delayed(es))
513 return true;
514
515 return false;
516}
517
518static inline struct extent_status *__es_alloc_extent(bool nofail)
519{
520 if (!nofail)
521 return kmem_cache_alloc(ext4_es_cachep, GFP_ATOMIC);
522
523 return kmem_cache_zalloc(ext4_es_cachep, GFP_KERNEL | __GFP_NOFAIL);
524}
525
526static void ext4_es_init_extent(struct inode *inode, struct extent_status *es,
527 ext4_lblk_t lblk, ext4_lblk_t len, ext4_fsblk_t pblk)
528{
529 es->es_lblk = lblk;
530 es->es_len = len;
531 es->es_pblk = pblk;
532
533 /* We never try to reclaim a must kept extent, so we don't count it. */
534 if (!ext4_es_must_keep(es)) {
535 if (!EXT4_I(inode)->i_es_shk_nr++)
536 ext4_es_list_add(inode);
537 percpu_counter_inc(fbc: &EXT4_SB(sb: inode->i_sb)->
538 s_es_stats.es_stats_shk_cnt);
539 }
540
541 EXT4_I(inode)->i_es_all_nr++;
542 percpu_counter_inc(fbc: &EXT4_SB(sb: inode->i_sb)->s_es_stats.es_stats_all_cnt);
543}
544
545static inline void __es_free_extent(struct extent_status *es)
546{
547 kmem_cache_free(s: ext4_es_cachep, objp: es);
548}
549
550static void ext4_es_free_extent(struct inode *inode, struct extent_status *es)
551{
552 EXT4_I(inode)->i_es_all_nr--;
553 percpu_counter_dec(fbc: &EXT4_SB(sb: inode->i_sb)->s_es_stats.es_stats_all_cnt);
554
555 /* Decrease the shrink counter when we can reclaim the extent. */
556 if (!ext4_es_must_keep(es)) {
557 BUG_ON(EXT4_I(inode)->i_es_shk_nr == 0);
558 if (!--EXT4_I(inode)->i_es_shk_nr)
559 ext4_es_list_del(inode);
560 percpu_counter_dec(fbc: &EXT4_SB(sb: inode->i_sb)->
561 s_es_stats.es_stats_shk_cnt);
562 }
563
564 __es_free_extent(es);
565}
566
567/*
568 * Check whether or not two extents can be merged
569 * Condition:
570 * - logical block number is contiguous
571 * - physical block number is contiguous
572 * - status is equal
573 */
574static int ext4_es_can_be_merged(struct extent_status *es1,
575 struct extent_status *es2)
576{
577 if (ext4_es_type(es: es1) != ext4_es_type(es: es2))
578 return 0;
579
580 if (((__u64) es1->es_len) + es2->es_len > EXT_MAX_BLOCKS) {
581 pr_warn("ES assertion failed when merging extents. "
582 "The sum of lengths of es1 (%d) and es2 (%d) "
583 "is bigger than allowed file size (%d)\n",
584 es1->es_len, es2->es_len, EXT_MAX_BLOCKS);
585 WARN_ON(1);
586 return 0;
587 }
588
589 if (((__u64) es1->es_lblk) + es1->es_len != es2->es_lblk)
590 return 0;
591
592 if ((ext4_es_is_written(es: es1) || ext4_es_is_unwritten(es: es1)) &&
593 (ext4_es_pblock(es: es1) + es1->es_len == ext4_es_pblock(es: es2)))
594 return 1;
595
596 if (ext4_es_is_hole(es: es1))
597 return 1;
598
599 /* we need to check delayed extent */
600 if (ext4_es_is_delayed(es: es1))
601 return 1;
602
603 return 0;
604}
605
606static struct extent_status *
607ext4_es_try_to_merge_left(struct inode *inode, struct extent_status *es)
608{
609 struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
610 struct extent_status *es1;
611 struct rb_node *node;
612
613 node = rb_prev(&es->rb_node);
614 if (!node)
615 return es;
616
617 es1 = rb_entry(node, struct extent_status, rb_node);
618 if (ext4_es_can_be_merged(es1, es2: es)) {
619 es1->es_len += es->es_len;
620 if (ext4_es_is_referenced(es))
621 ext4_es_set_referenced(es: es1);
622 rb_erase(&es->rb_node, &tree->root);
623 ext4_es_free_extent(inode, es);
624 es = es1;
625 }
626
627 return es;
628}
629
630static struct extent_status *
631ext4_es_try_to_merge_right(struct inode *inode, struct extent_status *es)
632{
633 struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
634 struct extent_status *es1;
635 struct rb_node *node;
636
637 node = rb_next(&es->rb_node);
638 if (!node)
639 return es;
640
641 es1 = rb_entry(node, struct extent_status, rb_node);
642 if (ext4_es_can_be_merged(es1: es, es2: es1)) {
643 es->es_len += es1->es_len;
644 if (ext4_es_is_referenced(es: es1))
645 ext4_es_set_referenced(es);
646 rb_erase(node, &tree->root);
647 ext4_es_free_extent(inode, es: es1);
648 }
649
650 return es;
651}
652
653#ifdef ES_AGGRESSIVE_TEST
654#include "ext4_extents.h" /* Needed when ES_AGGRESSIVE_TEST is defined */
655
656static void ext4_es_insert_extent_ext_check(struct inode *inode,
657 struct extent_status *es)
658{
659 struct ext4_ext_path *path = NULL;
660 struct ext4_extent *ex;
661 ext4_lblk_t ee_block;
662 ext4_fsblk_t ee_start;
663 unsigned short ee_len;
664 int depth, ee_status, es_status;
665
666 path = ext4_find_extent(inode, es->es_lblk, NULL, EXT4_EX_NOCACHE);
667 if (IS_ERR(path))
668 return;
669
670 depth = ext_depth(inode);
671 ex = path[depth].p_ext;
672
673 if (ex) {
674
675 ee_block = le32_to_cpu(ex->ee_block);
676 ee_start = ext4_ext_pblock(ex);
677 ee_len = ext4_ext_get_actual_len(ex);
678
679 ee_status = ext4_ext_is_unwritten(ex) ? 1 : 0;
680 es_status = ext4_es_is_unwritten(es) ? 1 : 0;
681
682 /*
683 * Make sure ex and es are not overlap when we try to insert
684 * a delayed/hole extent.
685 */
686 if (!ext4_es_is_written(es) && !ext4_es_is_unwritten(es)) {
687 if (in_range(es->es_lblk, ee_block, ee_len)) {
688 pr_warn("ES insert assertion failed for "
689 "inode: %lu we can find an extent "
690 "at block [%d/%d/%llu/%c], but we "
691 "want to add a delayed/hole extent "
692 "[%d/%d/%llu/%x]\n",
693 inode->i_ino, ee_block, ee_len,
694 ee_start, ee_status ? 'u' : 'w',
695 es->es_lblk, es->es_len,
696 ext4_es_pblock(es), ext4_es_status(es));
697 }
698 goto out;
699 }
700
701 /*
702 * We don't check ee_block == es->es_lblk, etc. because es
703 * might be a part of whole extent, vice versa.
704 */
705 if (es->es_lblk < ee_block ||
706 ext4_es_pblock(es) != ee_start + es->es_lblk - ee_block) {
707 pr_warn("ES insert assertion failed for inode: %lu "
708 "ex_status [%d/%d/%llu/%c] != "
709 "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
710 ee_block, ee_len, ee_start,
711 ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
712 ext4_es_pblock(es), es_status ? 'u' : 'w');
713 goto out;
714 }
715
716 if (ee_status ^ es_status) {
717 pr_warn("ES insert assertion failed for inode: %lu "
718 "ex_status [%d/%d/%llu/%c] != "
719 "es_status [%d/%d/%llu/%c]\n", inode->i_ino,
720 ee_block, ee_len, ee_start,
721 ee_status ? 'u' : 'w', es->es_lblk, es->es_len,
722 ext4_es_pblock(es), es_status ? 'u' : 'w');
723 }
724 } else {
725 /*
726 * We can't find an extent on disk. So we need to make sure
727 * that we don't want to add an written/unwritten extent.
728 */
729 if (!ext4_es_is_delayed(es) && !ext4_es_is_hole(es)) {
730 pr_warn("ES insert assertion failed for inode: %lu "
731 "can't find an extent at block %d but we want "
732 "to add a written/unwritten extent "
733 "[%d/%d/%llu/%x]\n", inode->i_ino,
734 es->es_lblk, es->es_lblk, es->es_len,
735 ext4_es_pblock(es), ext4_es_status(es));
736 }
737 }
738out:
739 ext4_free_ext_path(path);
740}
741
742static void ext4_es_insert_extent_ind_check(struct inode *inode,
743 struct extent_status *es)
744{
745 struct ext4_map_blocks map;
746 int retval;
747
748 /*
749 * Here we call ext4_ind_map_blocks to lookup a block mapping because
750 * 'Indirect' structure is defined in indirect.c. So we couldn't
751 * access direct/indirect tree from outside. It is too dirty to define
752 * this function in indirect.c file.
753 */
754
755 map.m_lblk = es->es_lblk;
756 map.m_len = es->es_len;
757
758 retval = ext4_ind_map_blocks(NULL, inode, &map, 0);
759 if (retval > 0) {
760 if (ext4_es_is_delayed(es) || ext4_es_is_hole(es)) {
761 /*
762 * We want to add a delayed/hole extent but this
763 * block has been allocated.
764 */
765 pr_warn("ES insert assertion failed for inode: %lu "
766 "We can find blocks but we want to add a "
767 "delayed/hole extent [%d/%d/%llu/%x]\n",
768 inode->i_ino, es->es_lblk, es->es_len,
769 ext4_es_pblock(es), ext4_es_status(es));
770 return;
771 } else if (ext4_es_is_written(es)) {
772 if (retval != es->es_len) {
773 pr_warn("ES insert assertion failed for "
774 "inode: %lu retval %d != es_len %d\n",
775 inode->i_ino, retval, es->es_len);
776 return;
777 }
778 if (map.m_pblk != ext4_es_pblock(es)) {
779 pr_warn("ES insert assertion failed for "
780 "inode: %lu m_pblk %llu != "
781 "es_pblk %llu\n",
782 inode->i_ino, map.m_pblk,
783 ext4_es_pblock(es));
784 return;
785 }
786 } else {
787 /*
788 * We don't need to check unwritten extent because
789 * indirect-based file doesn't have it.
790 */
791 BUG();
792 }
793 } else if (retval == 0) {
794 if (ext4_es_is_written(es)) {
795 pr_warn("ES insert assertion failed for inode: %lu "
796 "We can't find the block but we want to add "
797 "a written extent [%d/%d/%llu/%x]\n",
798 inode->i_ino, es->es_lblk, es->es_len,
799 ext4_es_pblock(es), ext4_es_status(es));
800 return;
801 }
802 }
803}
804
805static inline void ext4_es_insert_extent_check(struct inode *inode,
806 struct extent_status *es)
807{
808 /*
809 * We don't need to worry about the race condition because
810 * caller takes i_data_sem locking.
811 */
812 BUG_ON(!rwsem_is_locked(&EXT4_I(inode)->i_data_sem));
813 if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
814 ext4_es_insert_extent_ext_check(inode, es);
815 else
816 ext4_es_insert_extent_ind_check(inode, es);
817}
818#else
819static inline void ext4_es_insert_extent_check(struct inode *inode,
820 struct extent_status *es)
821{
822}
823#endif
824
825static int __es_insert_extent(struct inode *inode, struct extent_status *newes,
826 struct extent_status *prealloc)
827{
828 struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
829 struct rb_node **p = &tree->root.rb_node;
830 struct rb_node *parent = NULL;
831 struct extent_status *es;
832
833 while (*p) {
834 parent = *p;
835 es = rb_entry(parent, struct extent_status, rb_node);
836
837 if (newes->es_lblk < es->es_lblk) {
838 if (ext4_es_can_be_merged(es1: newes, es2: es)) {
839 /*
840 * Here we can modify es_lblk directly
841 * because it isn't overlapped.
842 */
843 es->es_lblk = newes->es_lblk;
844 es->es_len += newes->es_len;
845 if (ext4_es_is_written(es) ||
846 ext4_es_is_unwritten(es))
847 ext4_es_store_pblock(es,
848 pb: newes->es_pblk);
849 es = ext4_es_try_to_merge_left(inode, es);
850 goto out;
851 }
852 p = &(*p)->rb_left;
853 } else if (newes->es_lblk > ext4_es_end(es)) {
854 if (ext4_es_can_be_merged(es1: es, es2: newes)) {
855 es->es_len += newes->es_len;
856 es = ext4_es_try_to_merge_right(inode, es);
857 goto out;
858 }
859 p = &(*p)->rb_right;
860 } else {
861 BUG();
862 return -EINVAL;
863 }
864 }
865
866 if (prealloc)
867 es = prealloc;
868 else
869 es = __es_alloc_extent(nofail: false);
870 if (!es)
871 return -ENOMEM;
872 ext4_es_init_extent(inode, es, lblk: newes->es_lblk, len: newes->es_len,
873 pblk: newes->es_pblk);
874
875 rb_link_node(node: &es->rb_node, parent, rb_link: p);
876 rb_insert_color(&es->rb_node, &tree->root);
877
878out:
879 tree->cache_es = es;
880 return 0;
881}
882
883/*
884 * ext4_es_insert_extent() adds information to an inode's extent
885 * status tree.
886 */
887void ext4_es_insert_extent(struct inode *inode, ext4_lblk_t lblk,
888 ext4_lblk_t len, ext4_fsblk_t pblk,
889 unsigned int status, bool delalloc_reserve_used)
890{
891 struct extent_status newes;
892 ext4_lblk_t end = lblk + len - 1;
893 int err1 = 0, err2 = 0, err3 = 0;
894 int resv_used = 0, pending = 0;
895 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
896 struct extent_status *es1 = NULL;
897 struct extent_status *es2 = NULL;
898 struct pending_reservation *pr = NULL;
899 bool revise_pending = false;
900
901 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
902 return;
903
904 es_debug("add [%u/%u) %llu %x %d to extent status tree of inode %lu\n",
905 lblk, len, pblk, status, delalloc_reserve_used, inode->i_ino);
906
907 if (!len)
908 return;
909
910 BUG_ON(end < lblk);
911 WARN_ON_ONCE(status & EXTENT_STATUS_DELAYED);
912
913 newes.es_lblk = lblk;
914 newes.es_len = len;
915 ext4_es_store_pblock_status(es: &newes, pb: pblk, status);
916
917 ext4_es_insert_extent_check(inode, es: &newes);
918
919 revise_pending = sbi->s_cluster_ratio > 1 &&
920 test_opt(inode->i_sb, DELALLOC) &&
921 (status & (EXTENT_STATUS_WRITTEN |
922 EXTENT_STATUS_UNWRITTEN));
923retry:
924 if (err1 && !es1)
925 es1 = __es_alloc_extent(nofail: true);
926 if ((err1 || err2) && !es2)
927 es2 = __es_alloc_extent(nofail: true);
928 if ((err1 || err2 || err3 < 0) && revise_pending && !pr)
929 pr = __alloc_pending(nofail: true);
930 write_lock(&EXT4_I(inode)->i_es_lock);
931
932 err1 = __es_remove_extent(inode, lblk, end, reserved: &resv_used, prealloc: es1);
933 if (err1 != 0)
934 goto error;
935 /* Free preallocated extent if it didn't get used. */
936 if (es1) {
937 if (!es1->es_len)
938 __es_free_extent(es: es1);
939 es1 = NULL;
940 }
941
942 err2 = __es_insert_extent(inode, newes: &newes, prealloc: es2);
943 if (err2 == -ENOMEM && !ext4_es_must_keep(es: &newes))
944 err2 = 0;
945 if (err2 != 0)
946 goto error;
947 /* Free preallocated extent if it didn't get used. */
948 if (es2) {
949 if (!es2->es_len)
950 __es_free_extent(es: es2);
951 es2 = NULL;
952 }
953
954 if (revise_pending) {
955 err3 = __revise_pending(inode, lblk, len, prealloc: &pr);
956 if (err3 < 0)
957 goto error;
958 if (pr) {
959 __free_pending(pr);
960 pr = NULL;
961 }
962 pending = err3;
963 }
964 /*
965 * TODO: For cache on-disk extents, there is no need to increment
966 * the sequence counter, this requires future optimization.
967 */
968 ext4_es_inc_seq(inode);
969error:
970 write_unlock(&EXT4_I(inode)->i_es_lock);
971 /*
972 * Reduce the reserved cluster count to reflect successful deferred
973 * allocation of delayed allocated clusters or direct allocation of
974 * clusters discovered to be delayed allocated. Once allocated, a
975 * cluster is not included in the reserved count.
976 *
977 * When direct allocating (from fallocate, filemap, DIO, or clusters
978 * allocated when delalloc has been disabled by ext4_nonda_switch())
979 * an extent either 1) contains delayed blocks but start with
980 * non-delayed allocated blocks (e.g. hole) or 2) contains non-delayed
981 * allocated blocks which belong to delayed allocated clusters when
982 * bigalloc feature is enabled, quota has already been claimed by
983 * ext4_mb_new_blocks(), so release the quota reservations made for
984 * any previously delayed allocated clusters instead of claim them
985 * again.
986 */
987 resv_used += pending;
988 if (resv_used)
989 ext4_da_update_reserve_space(inode, used: resv_used,
990 quota_claim: delalloc_reserve_used);
991
992 if (err1 || err2 || err3 < 0)
993 goto retry;
994
995 trace_ext4_es_insert_extent(inode, es: &newes);
996 ext4_es_print_tree(inode);
997 return;
998}
999
1000/*
1001 * ext4_es_cache_extent() inserts information into the extent status
1002 * tree if and only if there isn't information about the range in
1003 * question already.
1004 */
1005void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
1006 ext4_lblk_t len, ext4_fsblk_t pblk,
1007 unsigned int status)
1008{
1009 struct extent_status *es;
1010 struct extent_status newes;
1011 ext4_lblk_t end = lblk + len - 1;
1012
1013 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
1014 return;
1015
1016 newes.es_lblk = lblk;
1017 newes.es_len = len;
1018 ext4_es_store_pblock_status(es: &newes, pb: pblk, status);
1019 trace_ext4_es_cache_extent(inode, es: &newes);
1020
1021 if (!len)
1022 return;
1023
1024 BUG_ON(end < lblk);
1025
1026 write_lock(&EXT4_I(inode)->i_es_lock);
1027
1028 es = __es_tree_search(root: &EXT4_I(inode)->i_es_tree.root, lblk);
1029 if (!es || es->es_lblk > end)
1030 __es_insert_extent(inode, newes: &newes, NULL);
1031 write_unlock(&EXT4_I(inode)->i_es_lock);
1032}
1033
1034/*
1035 * ext4_es_lookup_extent() looks up an extent in extent status tree.
1036 *
1037 * ext4_es_lookup_extent is called by ext4_map_blocks/ext4_da_map_blocks.
1038 *
1039 * Return: 1 on found, 0 on not
1040 */
1041int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
1042 ext4_lblk_t *next_lblk, struct extent_status *es,
1043 u64 *pseq)
1044{
1045 struct ext4_es_tree *tree;
1046 struct ext4_es_stats *stats;
1047 struct extent_status *es1 = NULL;
1048 struct rb_node *node;
1049 int found = 0;
1050
1051 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
1052 return 0;
1053
1054 trace_ext4_es_lookup_extent_enter(inode, lblk);
1055 es_debug("lookup extent in block %u\n", lblk);
1056
1057 tree = &EXT4_I(inode)->i_es_tree;
1058 read_lock(&EXT4_I(inode)->i_es_lock);
1059
1060 /* find extent in cache firstly */
1061 es->es_lblk = es->es_len = es->es_pblk = 0;
1062 es1 = READ_ONCE(tree->cache_es);
1063 if (es1 && in_range(lblk, es1->es_lblk, es1->es_len)) {
1064 es_debug("%u cached by [%u/%u)\n",
1065 lblk, es1->es_lblk, es1->es_len);
1066 found = 1;
1067 goto out;
1068 }
1069
1070 node = tree->root.rb_node;
1071 while (node) {
1072 es1 = rb_entry(node, struct extent_status, rb_node);
1073 if (lblk < es1->es_lblk)
1074 node = node->rb_left;
1075 else if (lblk > ext4_es_end(es: es1))
1076 node = node->rb_right;
1077 else {
1078 found = 1;
1079 break;
1080 }
1081 }
1082
1083out:
1084 stats = &EXT4_SB(sb: inode->i_sb)->s_es_stats;
1085 if (found) {
1086 BUG_ON(!es1);
1087 es->es_lblk = es1->es_lblk;
1088 es->es_len = es1->es_len;
1089 es->es_pblk = es1->es_pblk;
1090 if (!ext4_es_is_referenced(es: es1))
1091 ext4_es_set_referenced(es: es1);
1092 percpu_counter_inc(fbc: &stats->es_stats_cache_hits);
1093 if (next_lblk) {
1094 node = rb_next(&es1->rb_node);
1095 if (node) {
1096 es1 = rb_entry(node, struct extent_status,
1097 rb_node);
1098 *next_lblk = es1->es_lblk;
1099 } else
1100 *next_lblk = 0;
1101 }
1102 if (pseq)
1103 *pseq = EXT4_I(inode)->i_es_seq;
1104 } else {
1105 percpu_counter_inc(fbc: &stats->es_stats_cache_misses);
1106 }
1107
1108 read_unlock(&EXT4_I(inode)->i_es_lock);
1109
1110 trace_ext4_es_lookup_extent_exit(inode, es, found);
1111 return found;
1112}
1113
1114struct rsvd_count {
1115 int ndelayed;
1116 bool first_do_lblk_found;
1117 ext4_lblk_t first_do_lblk;
1118 ext4_lblk_t last_do_lblk;
1119 struct extent_status *left_es;
1120 bool partial;
1121 ext4_lblk_t lclu;
1122};
1123
1124/*
1125 * init_rsvd - initialize reserved count data before removing block range
1126 * in file from extent status tree
1127 *
1128 * @inode - file containing range
1129 * @lblk - first block in range
1130 * @es - pointer to first extent in range
1131 * @rc - pointer to reserved count data
1132 *
1133 * Assumes es is not NULL
1134 */
1135static void init_rsvd(struct inode *inode, ext4_lblk_t lblk,
1136 struct extent_status *es, struct rsvd_count *rc)
1137{
1138 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1139 struct rb_node *node;
1140
1141 rc->ndelayed = 0;
1142
1143 /*
1144 * for bigalloc, note the first delayed block in the range has not
1145 * been found, record the extent containing the block to the left of
1146 * the region to be removed, if any, and note that there's no partial
1147 * cluster to track
1148 */
1149 if (sbi->s_cluster_ratio > 1) {
1150 rc->first_do_lblk_found = false;
1151 if (lblk > es->es_lblk) {
1152 rc->left_es = es;
1153 } else {
1154 node = rb_prev(&es->rb_node);
1155 rc->left_es = node ? rb_entry(node,
1156 struct extent_status,
1157 rb_node) : NULL;
1158 }
1159 rc->partial = false;
1160 }
1161}
1162
1163/*
1164 * count_rsvd - count the clusters containing delayed blocks in a range
1165 * within an extent and add to the running tally in rsvd_count
1166 *
1167 * @inode - file containing extent
1168 * @lblk - first block in range
1169 * @len - length of range in blocks
1170 * @es - pointer to extent containing clusters to be counted
1171 * @rc - pointer to reserved count data
1172 *
1173 * Tracks partial clusters found at the beginning and end of extents so
1174 * they aren't overcounted when they span adjacent extents
1175 */
1176static void count_rsvd(struct inode *inode, ext4_lblk_t lblk, long len,
1177 struct extent_status *es, struct rsvd_count *rc)
1178{
1179 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1180 ext4_lblk_t i, end, nclu;
1181
1182 if (!ext4_es_is_delayed(es))
1183 return;
1184
1185 WARN_ON(len <= 0);
1186
1187 if (sbi->s_cluster_ratio == 1) {
1188 rc->ndelayed += (int) len;
1189 return;
1190 }
1191
1192 /* bigalloc */
1193
1194 i = (lblk < es->es_lblk) ? es->es_lblk : lblk;
1195 end = lblk + (ext4_lblk_t) len - 1;
1196 end = (end > ext4_es_end(es)) ? ext4_es_end(es) : end;
1197
1198 /* record the first block of the first delayed extent seen */
1199 if (!rc->first_do_lblk_found) {
1200 rc->first_do_lblk = i;
1201 rc->first_do_lblk_found = true;
1202 }
1203
1204 /* update the last lblk in the region seen so far */
1205 rc->last_do_lblk = end;
1206
1207 /*
1208 * if we're tracking a partial cluster and the current extent
1209 * doesn't start with it, count it and stop tracking
1210 */
1211 if (rc->partial && (rc->lclu != EXT4_B2C(sbi, i))) {
1212 rc->ndelayed++;
1213 rc->partial = false;
1214 }
1215
1216 /*
1217 * if the first cluster doesn't start on a cluster boundary but
1218 * ends on one, count it
1219 */
1220 if (EXT4_LBLK_COFF(sbi, i) != 0) {
1221 if (end >= EXT4_LBLK_CFILL(sbi, i)) {
1222 rc->ndelayed++;
1223 rc->partial = false;
1224 i = EXT4_LBLK_CFILL(sbi, i) + 1;
1225 }
1226 }
1227
1228 /*
1229 * if the current cluster starts on a cluster boundary, count the
1230 * number of whole delayed clusters in the extent
1231 */
1232 if ((i + sbi->s_cluster_ratio - 1) <= end) {
1233 nclu = (end - i + 1) >> sbi->s_cluster_bits;
1234 rc->ndelayed += nclu;
1235 i += nclu << sbi->s_cluster_bits;
1236 }
1237
1238 /*
1239 * start tracking a partial cluster if there's a partial at the end
1240 * of the current extent and we're not already tracking one
1241 */
1242 if (!rc->partial && i <= end) {
1243 rc->partial = true;
1244 rc->lclu = EXT4_B2C(sbi, i);
1245 }
1246}
1247
1248/*
1249 * __pr_tree_search - search for a pending cluster reservation
1250 *
1251 * @root - root of pending reservation tree
1252 * @lclu - logical cluster to search for
1253 *
1254 * Returns the pending reservation for the cluster identified by @lclu
1255 * if found. If not, returns a reservation for the next cluster if any,
1256 * and if not, returns NULL.
1257 */
1258static struct pending_reservation *__pr_tree_search(struct rb_root *root,
1259 ext4_lblk_t lclu)
1260{
1261 struct rb_node *node = root->rb_node;
1262 struct pending_reservation *pr = NULL;
1263
1264 while (node) {
1265 pr = rb_entry(node, struct pending_reservation, rb_node);
1266 if (lclu < pr->lclu)
1267 node = node->rb_left;
1268 else if (lclu > pr->lclu)
1269 node = node->rb_right;
1270 else
1271 return pr;
1272 }
1273 if (pr && lclu < pr->lclu)
1274 return pr;
1275 if (pr && lclu > pr->lclu) {
1276 node = rb_next(&pr->rb_node);
1277 return node ? rb_entry(node, struct pending_reservation,
1278 rb_node) : NULL;
1279 }
1280 return NULL;
1281}
1282
1283/*
1284 * get_rsvd - calculates and returns the number of cluster reservations to be
1285 * released when removing a block range from the extent status tree
1286 * and releases any pending reservations within the range
1287 *
1288 * @inode - file containing block range
1289 * @end - last block in range
1290 * @right_es - pointer to extent containing next block beyond end or NULL
1291 * @rc - pointer to reserved count data
1292 *
1293 * The number of reservations to be released is equal to the number of
1294 * clusters containing delayed blocks within the range, minus the number of
1295 * clusters still containing delayed blocks at the ends of the range, and
1296 * minus the number of pending reservations within the range.
1297 */
1298static unsigned int get_rsvd(struct inode *inode, ext4_lblk_t end,
1299 struct extent_status *right_es,
1300 struct rsvd_count *rc)
1301{
1302 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
1303 struct pending_reservation *pr;
1304 struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree;
1305 struct rb_node *node;
1306 ext4_lblk_t first_lclu, last_lclu;
1307 bool left_delayed, right_delayed, count_pending;
1308 struct extent_status *es;
1309
1310 if (sbi->s_cluster_ratio > 1) {
1311 /* count any remaining partial cluster */
1312 if (rc->partial)
1313 rc->ndelayed++;
1314
1315 if (rc->ndelayed == 0)
1316 return 0;
1317
1318 first_lclu = EXT4_B2C(sbi, rc->first_do_lblk);
1319 last_lclu = EXT4_B2C(sbi, rc->last_do_lblk);
1320
1321 /*
1322 * decrease the delayed count by the number of clusters at the
1323 * ends of the range that still contain delayed blocks -
1324 * these clusters still need to be reserved
1325 */
1326 left_delayed = right_delayed = false;
1327
1328 es = rc->left_es;
1329 while (es && ext4_es_end(es) >=
1330 EXT4_LBLK_CMASK(sbi, rc->first_do_lblk)) {
1331 if (ext4_es_is_delayed(es)) {
1332 rc->ndelayed--;
1333 left_delayed = true;
1334 break;
1335 }
1336 node = rb_prev(&es->rb_node);
1337 if (!node)
1338 break;
1339 es = rb_entry(node, struct extent_status, rb_node);
1340 }
1341 if (right_es && (!left_delayed || first_lclu != last_lclu)) {
1342 if (end < ext4_es_end(es: right_es)) {
1343 es = right_es;
1344 } else {
1345 node = rb_next(&right_es->rb_node);
1346 es = node ? rb_entry(node, struct extent_status,
1347 rb_node) : NULL;
1348 }
1349 while (es && es->es_lblk <=
1350 EXT4_LBLK_CFILL(sbi, rc->last_do_lblk)) {
1351 if (ext4_es_is_delayed(es)) {
1352 rc->ndelayed--;
1353 right_delayed = true;
1354 break;
1355 }
1356 node = rb_next(&es->rb_node);
1357 if (!node)
1358 break;
1359 es = rb_entry(node, struct extent_status,
1360 rb_node);
1361 }
1362 }
1363
1364 /*
1365 * Determine the block range that should be searched for
1366 * pending reservations, if any. Clusters on the ends of the
1367 * original removed range containing delayed blocks are
1368 * excluded. They've already been accounted for and it's not
1369 * possible to determine if an associated pending reservation
1370 * should be released with the information available in the
1371 * extents status tree.
1372 */
1373 if (first_lclu == last_lclu) {
1374 if (left_delayed | right_delayed)
1375 count_pending = false;
1376 else
1377 count_pending = true;
1378 } else {
1379 if (left_delayed)
1380 first_lclu++;
1381 if (right_delayed)
1382 last_lclu--;
1383 if (first_lclu <= last_lclu)
1384 count_pending = true;
1385 else
1386 count_pending = false;
1387 }
1388
1389 /*
1390 * a pending reservation found between first_lclu and last_lclu
1391 * represents an allocated cluster that contained at least one
1392 * delayed block, so the delayed total must be reduced by one
1393 * for each pending reservation found and released
1394 */
1395 if (count_pending) {
1396 pr = __pr_tree_search(root: &tree->root, lclu: first_lclu);
1397 while (pr && pr->lclu <= last_lclu) {
1398 rc->ndelayed--;
1399 node = rb_next(&pr->rb_node);
1400 rb_erase(&pr->rb_node, &tree->root);
1401 __free_pending(pr);
1402 if (!node)
1403 break;
1404 pr = rb_entry(node, struct pending_reservation,
1405 rb_node);
1406 }
1407 }
1408 }
1409 return rc->ndelayed;
1410}
1411
1412
1413/*
1414 * __es_remove_extent - removes block range from extent status tree
1415 *
1416 * @inode - file containing range
1417 * @lblk - first block in range
1418 * @end - last block in range
1419 * @reserved - number of cluster reservations released
1420 * @prealloc - pre-allocated es to avoid memory allocation failures
1421 *
1422 * If @reserved is not NULL and delayed allocation is enabled, counts
1423 * block/cluster reservations freed by removing range and if bigalloc
1424 * enabled cancels pending reservations as needed. Returns 0 on success,
1425 * error code on failure.
1426 */
1427static int __es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
1428 ext4_lblk_t end, int *reserved,
1429 struct extent_status *prealloc)
1430{
1431 struct ext4_es_tree *tree = &EXT4_I(inode)->i_es_tree;
1432 struct rb_node *node;
1433 struct extent_status *es;
1434 struct extent_status orig_es;
1435 ext4_lblk_t len1, len2;
1436 ext4_fsblk_t block;
1437 int err = 0;
1438 bool count_reserved = true;
1439 struct rsvd_count rc;
1440
1441 if (reserved == NULL || !test_opt(inode->i_sb, DELALLOC))
1442 count_reserved = false;
1443
1444 es = __es_tree_search(root: &tree->root, lblk);
1445 if (!es)
1446 goto out;
1447 if (es->es_lblk > end)
1448 goto out;
1449
1450 /* Simply invalidate cache_es. */
1451 tree->cache_es = NULL;
1452 if (count_reserved)
1453 init_rsvd(inode, lblk, es, rc: &rc);
1454
1455 orig_es.es_lblk = es->es_lblk;
1456 orig_es.es_len = es->es_len;
1457 orig_es.es_pblk = es->es_pblk;
1458
1459 len1 = lblk > es->es_lblk ? lblk - es->es_lblk : 0;
1460 len2 = ext4_es_end(es) > end ? ext4_es_end(es) - end : 0;
1461 if (len1 > 0)
1462 es->es_len = len1;
1463 if (len2 > 0) {
1464 if (len1 > 0) {
1465 struct extent_status newes;
1466
1467 newes.es_lblk = end + 1;
1468 newes.es_len = len2;
1469 block = 0x7FDEADBEEFULL;
1470 if (ext4_es_is_written(es: &orig_es) ||
1471 ext4_es_is_unwritten(es: &orig_es))
1472 block = ext4_es_pblock(es: &orig_es) +
1473 orig_es.es_len - len2;
1474 ext4_es_store_pblock_status(es: &newes, pb: block,
1475 status: ext4_es_status(es: &orig_es));
1476 err = __es_insert_extent(inode, newes: &newes, prealloc);
1477 if (err) {
1478 if (!ext4_es_must_keep(es: &newes))
1479 return 0;
1480
1481 es->es_lblk = orig_es.es_lblk;
1482 es->es_len = orig_es.es_len;
1483 goto out;
1484 }
1485 } else {
1486 es->es_lblk = end + 1;
1487 es->es_len = len2;
1488 if (ext4_es_is_written(es) ||
1489 ext4_es_is_unwritten(es)) {
1490 block = orig_es.es_pblk + orig_es.es_len - len2;
1491 ext4_es_store_pblock(es, pb: block);
1492 }
1493 }
1494 if (count_reserved)
1495 count_rsvd(inode, lblk: orig_es.es_lblk + len1,
1496 len: orig_es.es_len - len1 - len2, es: &orig_es, rc: &rc);
1497 goto out_get_reserved;
1498 }
1499
1500 if (len1 > 0) {
1501 if (count_reserved)
1502 count_rsvd(inode, lblk, len: orig_es.es_len - len1,
1503 es: &orig_es, rc: &rc);
1504 node = rb_next(&es->rb_node);
1505 if (node)
1506 es = rb_entry(node, struct extent_status, rb_node);
1507 else
1508 es = NULL;
1509 }
1510
1511 while (es && ext4_es_end(es) <= end) {
1512 if (count_reserved)
1513 count_rsvd(inode, lblk: es->es_lblk, len: es->es_len, es, rc: &rc);
1514 node = rb_next(&es->rb_node);
1515 rb_erase(&es->rb_node, &tree->root);
1516 ext4_es_free_extent(inode, es);
1517 if (!node) {
1518 es = NULL;
1519 break;
1520 }
1521 es = rb_entry(node, struct extent_status, rb_node);
1522 }
1523
1524 if (es && es->es_lblk < end + 1) {
1525 ext4_lblk_t orig_len = es->es_len;
1526
1527 len1 = ext4_es_end(es) - end;
1528 if (count_reserved)
1529 count_rsvd(inode, lblk: es->es_lblk, len: orig_len - len1,
1530 es, rc: &rc);
1531 es->es_lblk = end + 1;
1532 es->es_len = len1;
1533 if (ext4_es_is_written(es) || ext4_es_is_unwritten(es)) {
1534 block = es->es_pblk + orig_len - len1;
1535 ext4_es_store_pblock(es, pb: block);
1536 }
1537 }
1538
1539out_get_reserved:
1540 if (count_reserved)
1541 *reserved = get_rsvd(inode, end, right_es: es, rc: &rc);
1542out:
1543 return err;
1544}
1545
1546/*
1547 * ext4_es_remove_extent - removes block range from extent status tree
1548 *
1549 * @inode - file containing range
1550 * @lblk - first block in range
1551 * @len - number of blocks to remove
1552 *
1553 * Reduces block/cluster reservation count and for bigalloc cancels pending
1554 * reservations as needed.
1555 */
1556void ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk,
1557 ext4_lblk_t len)
1558{
1559 ext4_lblk_t end;
1560 int err = 0;
1561 int reserved = 0;
1562 struct extent_status *es = NULL;
1563
1564 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
1565 return;
1566
1567 es_debug("remove [%u/%u) from extent status tree of inode %lu\n",
1568 lblk, len, inode->i_ino);
1569
1570 if (!len)
1571 return;
1572
1573 end = lblk + len - 1;
1574 BUG_ON(end < lblk);
1575
1576retry:
1577 if (err && !es)
1578 es = __es_alloc_extent(nofail: true);
1579 /*
1580 * ext4_clear_inode() depends on us taking i_es_lock unconditionally
1581 * so that we are sure __es_shrink() is done with the inode before it
1582 * is reclaimed.
1583 */
1584 write_lock(&EXT4_I(inode)->i_es_lock);
1585 err = __es_remove_extent(inode, lblk, end, reserved: &reserved, prealloc: es);
1586 if (err)
1587 goto error;
1588 /* Free preallocated extent if it didn't get used. */
1589 if (es) {
1590 if (!es->es_len)
1591 __es_free_extent(es);
1592 es = NULL;
1593 }
1594 ext4_es_inc_seq(inode);
1595error:
1596 write_unlock(&EXT4_I(inode)->i_es_lock);
1597 if (err)
1598 goto retry;
1599
1600 trace_ext4_es_remove_extent(inode, lblk, len);
1601 ext4_es_print_tree(inode);
1602 ext4_da_release_space(inode, to_free: reserved);
1603}
1604
1605static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan,
1606 struct ext4_inode_info *locked_ei)
1607{
1608 struct ext4_inode_info *ei;
1609 struct ext4_es_stats *es_stats;
1610 ktime_t start_time;
1611 u64 scan_time;
1612 int nr_to_walk;
1613 int nr_shrunk = 0;
1614 int retried = 0, nr_skipped = 0;
1615
1616 es_stats = &sbi->s_es_stats;
1617 start_time = ktime_get();
1618
1619retry:
1620 spin_lock(lock: &sbi->s_es_lock);
1621 nr_to_walk = sbi->s_es_nr_inode;
1622 while (nr_to_walk-- > 0) {
1623 if (list_empty(head: &sbi->s_es_list)) {
1624 spin_unlock(lock: &sbi->s_es_lock);
1625 goto out;
1626 }
1627 ei = list_first_entry(&sbi->s_es_list, struct ext4_inode_info,
1628 i_es_list);
1629 /* Move the inode to the tail */
1630 list_move_tail(list: &ei->i_es_list, head: &sbi->s_es_list);
1631
1632 /*
1633 * Normally we try hard to avoid shrinking precached inodes,
1634 * but we will as a last resort.
1635 */
1636 if (!retried && ext4_test_inode_state(inode: &ei->vfs_inode,
1637 bit: EXT4_STATE_EXT_PRECACHED)) {
1638 nr_skipped++;
1639 continue;
1640 }
1641
1642 if (ei == locked_ei || !write_trylock(&ei->i_es_lock)) {
1643 nr_skipped++;
1644 continue;
1645 }
1646 /*
1647 * Now we hold i_es_lock which protects us from inode reclaim
1648 * freeing inode under us
1649 */
1650 spin_unlock(lock: &sbi->s_es_lock);
1651
1652 nr_shrunk += es_reclaim_extents(ei, nr_to_scan: &nr_to_scan);
1653 write_unlock(&ei->i_es_lock);
1654
1655 if (nr_to_scan <= 0)
1656 goto out;
1657 spin_lock(lock: &sbi->s_es_lock);
1658 }
1659 spin_unlock(lock: &sbi->s_es_lock);
1660
1661 /*
1662 * If we skipped any inodes, and we weren't able to make any
1663 * forward progress, try again to scan precached inodes.
1664 */
1665 if ((nr_shrunk == 0) && nr_skipped && !retried) {
1666 retried++;
1667 goto retry;
1668 }
1669
1670 if (locked_ei && nr_shrunk == 0)
1671 nr_shrunk = es_reclaim_extents(ei: locked_ei, nr_to_scan: &nr_to_scan);
1672
1673out:
1674 scan_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1675 if (likely(es_stats->es_stats_scan_time))
1676 es_stats->es_stats_scan_time = (scan_time +
1677 es_stats->es_stats_scan_time*3) / 4;
1678 else
1679 es_stats->es_stats_scan_time = scan_time;
1680 if (scan_time > es_stats->es_stats_max_scan_time)
1681 es_stats->es_stats_max_scan_time = scan_time;
1682 if (likely(es_stats->es_stats_shrunk))
1683 es_stats->es_stats_shrunk = (nr_shrunk +
1684 es_stats->es_stats_shrunk*3) / 4;
1685 else
1686 es_stats->es_stats_shrunk = nr_shrunk;
1687
1688 trace_ext4_es_shrink(sb: sbi->s_sb, nr_shrunk, scan_time,
1689 nr_skipped, retried);
1690 return nr_shrunk;
1691}
1692
1693static unsigned long ext4_es_count(struct shrinker *shrink,
1694 struct shrink_control *sc)
1695{
1696 unsigned long nr;
1697 struct ext4_sb_info *sbi;
1698
1699 sbi = shrink->private_data;
1700 nr = percpu_counter_read_positive(fbc: &sbi->s_es_stats.es_stats_shk_cnt);
1701 trace_ext4_es_shrink_count(sb: sbi->s_sb, nr_to_scan: sc->nr_to_scan, cache_cnt: nr);
1702 return nr;
1703}
1704
1705static unsigned long ext4_es_scan(struct shrinker *shrink,
1706 struct shrink_control *sc)
1707{
1708 struct ext4_sb_info *sbi = shrink->private_data;
1709 int nr_to_scan = sc->nr_to_scan;
1710 int ret, nr_shrunk;
1711
1712 ret = percpu_counter_read_positive(fbc: &sbi->s_es_stats.es_stats_shk_cnt);
1713 trace_ext4_es_shrink_scan_enter(sb: sbi->s_sb, nr_to_scan, cache_cnt: ret);
1714
1715 nr_shrunk = __es_shrink(sbi, nr_to_scan, NULL);
1716
1717 ret = percpu_counter_read_positive(fbc: &sbi->s_es_stats.es_stats_shk_cnt);
1718 trace_ext4_es_shrink_scan_exit(sb: sbi->s_sb, nr_shrunk, cache_cnt: ret);
1719 return nr_shrunk;
1720}
1721
1722int ext4_seq_es_shrinker_info_show(struct seq_file *seq, void *v)
1723{
1724 struct ext4_sb_info *sbi = EXT4_SB(sb: (struct super_block *) seq->private);
1725 struct ext4_es_stats *es_stats = &sbi->s_es_stats;
1726 struct ext4_inode_info *ei, *max = NULL;
1727 unsigned int inode_cnt = 0;
1728
1729 if (v != SEQ_START_TOKEN)
1730 return 0;
1731
1732 /* here we just find an inode that has the max nr. of objects */
1733 spin_lock(lock: &sbi->s_es_lock);
1734 list_for_each_entry(ei, &sbi->s_es_list, i_es_list) {
1735 inode_cnt++;
1736 if (max && max->i_es_all_nr < ei->i_es_all_nr)
1737 max = ei;
1738 else if (!max)
1739 max = ei;
1740 }
1741 spin_unlock(lock: &sbi->s_es_lock);
1742
1743 seq_printf(m: seq, fmt: "stats:\n %lld objects\n %lld reclaimable objects\n",
1744 percpu_counter_sum_positive(fbc: &es_stats->es_stats_all_cnt),
1745 percpu_counter_sum_positive(fbc: &es_stats->es_stats_shk_cnt));
1746 seq_printf(m: seq, fmt: " %lld/%lld cache hits/misses\n",
1747 percpu_counter_sum_positive(fbc: &es_stats->es_stats_cache_hits),
1748 percpu_counter_sum_positive(fbc: &es_stats->es_stats_cache_misses));
1749 if (inode_cnt)
1750 seq_printf(m: seq, fmt: " %d inodes on list\n", inode_cnt);
1751
1752 seq_printf(m: seq, fmt: "average:\n %llu us scan time\n",
1753 div_u64(dividend: es_stats->es_stats_scan_time, divisor: 1000));
1754 seq_printf(m: seq, fmt: " %lu shrunk objects\n", es_stats->es_stats_shrunk);
1755 if (inode_cnt)
1756 seq_printf(m: seq,
1757 fmt: "maximum:\n %lu inode (%u objects, %u reclaimable)\n"
1758 " %llu us max scan time\n",
1759 max->vfs_inode.i_ino, max->i_es_all_nr, max->i_es_shk_nr,
1760 div_u64(dividend: es_stats->es_stats_max_scan_time, divisor: 1000));
1761
1762 return 0;
1763}
1764
1765int ext4_es_register_shrinker(struct ext4_sb_info *sbi)
1766{
1767 int err;
1768
1769 /* Make sure we have enough bits for physical block number */
1770 BUILD_BUG_ON(ES_SHIFT < 48);
1771 INIT_LIST_HEAD(list: &sbi->s_es_list);
1772 sbi->s_es_nr_inode = 0;
1773 spin_lock_init(&sbi->s_es_lock);
1774 sbi->s_es_stats.es_stats_shrunk = 0;
1775 err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_hits, 0,
1776 GFP_KERNEL);
1777 if (err)
1778 return err;
1779 err = percpu_counter_init(&sbi->s_es_stats.es_stats_cache_misses, 0,
1780 GFP_KERNEL);
1781 if (err)
1782 goto err1;
1783 sbi->s_es_stats.es_stats_scan_time = 0;
1784 sbi->s_es_stats.es_stats_max_scan_time = 0;
1785 err = percpu_counter_init(&sbi->s_es_stats.es_stats_all_cnt, 0, GFP_KERNEL);
1786 if (err)
1787 goto err2;
1788 err = percpu_counter_init(&sbi->s_es_stats.es_stats_shk_cnt, 0, GFP_KERNEL);
1789 if (err)
1790 goto err3;
1791
1792 sbi->s_es_shrinker = shrinker_alloc(flags: 0, fmt: "ext4-es:%s", sbi->s_sb->s_id);
1793 if (!sbi->s_es_shrinker) {
1794 err = -ENOMEM;
1795 goto err4;
1796 }
1797
1798 sbi->s_es_shrinker->scan_objects = ext4_es_scan;
1799 sbi->s_es_shrinker->count_objects = ext4_es_count;
1800 sbi->s_es_shrinker->private_data = sbi;
1801
1802 shrinker_register(shrinker: sbi->s_es_shrinker);
1803
1804 return 0;
1805err4:
1806 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_shk_cnt);
1807err3:
1808 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_all_cnt);
1809err2:
1810 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_cache_misses);
1811err1:
1812 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_cache_hits);
1813 return err;
1814}
1815
1816void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi)
1817{
1818 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_cache_hits);
1819 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_cache_misses);
1820 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_all_cnt);
1821 percpu_counter_destroy(fbc: &sbi->s_es_stats.es_stats_shk_cnt);
1822 shrinker_free(shrinker: sbi->s_es_shrinker);
1823}
1824
1825/*
1826 * Shrink extents in given inode from ei->i_es_shrink_lblk till end. Scan at
1827 * most *nr_to_scan extents, update *nr_to_scan accordingly.
1828 *
1829 * Return 0 if we hit end of tree / interval, 1 if we exhausted nr_to_scan.
1830 * Increment *nr_shrunk by the number of reclaimed extents. Also update
1831 * ei->i_es_shrink_lblk to where we should continue scanning.
1832 */
1833static int es_do_reclaim_extents(struct ext4_inode_info *ei, ext4_lblk_t end,
1834 int *nr_to_scan, int *nr_shrunk)
1835{
1836 struct inode *inode = &ei->vfs_inode;
1837 struct ext4_es_tree *tree = &ei->i_es_tree;
1838 struct extent_status *es;
1839 struct rb_node *node;
1840
1841 es = __es_tree_search(root: &tree->root, lblk: ei->i_es_shrink_lblk);
1842 if (!es)
1843 goto out_wrap;
1844
1845 while (*nr_to_scan > 0) {
1846 if (es->es_lblk > end) {
1847 ei->i_es_shrink_lblk = end + 1;
1848 return 0;
1849 }
1850
1851 (*nr_to_scan)--;
1852 node = rb_next(&es->rb_node);
1853
1854 if (ext4_es_must_keep(es))
1855 goto next;
1856 if (ext4_es_is_referenced(es)) {
1857 ext4_es_clear_referenced(es);
1858 goto next;
1859 }
1860
1861 rb_erase(&es->rb_node, &tree->root);
1862 ext4_es_free_extent(inode, es);
1863 (*nr_shrunk)++;
1864next:
1865 if (!node)
1866 goto out_wrap;
1867 es = rb_entry(node, struct extent_status, rb_node);
1868 }
1869 ei->i_es_shrink_lblk = es->es_lblk;
1870 return 1;
1871out_wrap:
1872 ei->i_es_shrink_lblk = 0;
1873 return 0;
1874}
1875
1876static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan)
1877{
1878 struct inode *inode = &ei->vfs_inode;
1879 int nr_shrunk = 0;
1880 ext4_lblk_t start = ei->i_es_shrink_lblk;
1881 static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
1882 DEFAULT_RATELIMIT_BURST);
1883
1884 if (ei->i_es_shk_nr == 0)
1885 return 0;
1886
1887 if (ext4_test_inode_state(inode, bit: EXT4_STATE_EXT_PRECACHED) &&
1888 __ratelimit(&_rs))
1889 ext4_warning(inode->i_sb, "forced shrink of precached extents");
1890
1891 if (!es_do_reclaim_extents(ei, EXT_MAX_BLOCKS, nr_to_scan, nr_shrunk: &nr_shrunk) &&
1892 start != 0)
1893 es_do_reclaim_extents(ei, end: start - 1, nr_to_scan, nr_shrunk: &nr_shrunk);
1894
1895 ei->i_es_tree.cache_es = NULL;
1896 return nr_shrunk;
1897}
1898
1899/*
1900 * Called to support EXT4_IOC_CLEAR_ES_CACHE. We can only remove
1901 * discretionary entries from the extent status cache. (Some entries
1902 * must be present for proper operations.)
1903 */
1904void ext4_clear_inode_es(struct inode *inode)
1905{
1906 struct ext4_inode_info *ei = EXT4_I(inode);
1907 struct extent_status *es;
1908 struct ext4_es_tree *tree;
1909 struct rb_node *node;
1910
1911 write_lock(&ei->i_es_lock);
1912 tree = &EXT4_I(inode)->i_es_tree;
1913 tree->cache_es = NULL;
1914 node = rb_first(root: &tree->root);
1915 while (node) {
1916 es = rb_entry(node, struct extent_status, rb_node);
1917 node = rb_next(node);
1918 if (!ext4_es_must_keep(es)) {
1919 rb_erase(&es->rb_node, &tree->root);
1920 ext4_es_free_extent(inode, es);
1921 }
1922 }
1923 ext4_clear_inode_state(inode, bit: EXT4_STATE_EXT_PRECACHED);
1924 write_unlock(&ei->i_es_lock);
1925}
1926
1927#ifdef ES_DEBUG__
1928static void ext4_print_pending_tree(struct inode *inode)
1929{
1930 struct ext4_pending_tree *tree;
1931 struct rb_node *node;
1932 struct pending_reservation *pr;
1933
1934 printk(KERN_DEBUG "pending reservations for inode %lu:", inode->i_ino);
1935 tree = &EXT4_I(inode)->i_pending_tree;
1936 node = rb_first(&tree->root);
1937 while (node) {
1938 pr = rb_entry(node, struct pending_reservation, rb_node);
1939 printk(KERN_DEBUG " %u", pr->lclu);
1940 node = rb_next(node);
1941 }
1942 printk(KERN_DEBUG "\n");
1943}
1944#else
1945#define ext4_print_pending_tree(inode)
1946#endif
1947
1948int __init ext4_init_pending(void)
1949{
1950 ext4_pending_cachep = KMEM_CACHE(pending_reservation, SLAB_RECLAIM_ACCOUNT);
1951 if (ext4_pending_cachep == NULL)
1952 return -ENOMEM;
1953 return 0;
1954}
1955
1956void ext4_exit_pending(void)
1957{
1958 kmem_cache_destroy(s: ext4_pending_cachep);
1959}
1960
1961void ext4_init_pending_tree(struct ext4_pending_tree *tree)
1962{
1963 tree->root = RB_ROOT;
1964}
1965
1966/*
1967 * __get_pending - retrieve a pointer to a pending reservation
1968 *
1969 * @inode - file containing the pending cluster reservation
1970 * @lclu - logical cluster of interest
1971 *
1972 * Returns a pointer to a pending reservation if it's a member of
1973 * the set, and NULL if not. Must be called holding i_es_lock.
1974 */
1975static struct pending_reservation *__get_pending(struct inode *inode,
1976 ext4_lblk_t lclu)
1977{
1978 struct ext4_pending_tree *tree;
1979 struct rb_node *node;
1980 struct pending_reservation *pr = NULL;
1981
1982 tree = &EXT4_I(inode)->i_pending_tree;
1983 node = (&tree->root)->rb_node;
1984
1985 while (node) {
1986 pr = rb_entry(node, struct pending_reservation, rb_node);
1987 if (lclu < pr->lclu)
1988 node = node->rb_left;
1989 else if (lclu > pr->lclu)
1990 node = node->rb_right;
1991 else if (lclu == pr->lclu)
1992 return pr;
1993 }
1994 return NULL;
1995}
1996
1997/*
1998 * __insert_pending - adds a pending cluster reservation to the set of
1999 * pending reservations
2000 *
2001 * @inode - file containing the cluster
2002 * @lblk - logical block in the cluster to be added
2003 * @prealloc - preallocated pending entry
2004 *
2005 * Returns 1 on successful insertion and -ENOMEM on failure. If the
2006 * pending reservation is already in the set, returns successfully.
2007 */
2008static int __insert_pending(struct inode *inode, ext4_lblk_t lblk,
2009 struct pending_reservation **prealloc)
2010{
2011 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
2012 struct ext4_pending_tree *tree = &EXT4_I(inode)->i_pending_tree;
2013 struct rb_node **p = &tree->root.rb_node;
2014 struct rb_node *parent = NULL;
2015 struct pending_reservation *pr;
2016 ext4_lblk_t lclu;
2017 int ret = 0;
2018
2019 lclu = EXT4_B2C(sbi, lblk);
2020 /* search to find parent for insertion */
2021 while (*p) {
2022 parent = *p;
2023 pr = rb_entry(parent, struct pending_reservation, rb_node);
2024
2025 if (lclu < pr->lclu) {
2026 p = &(*p)->rb_left;
2027 } else if (lclu > pr->lclu) {
2028 p = &(*p)->rb_right;
2029 } else {
2030 /* pending reservation already inserted */
2031 goto out;
2032 }
2033 }
2034
2035 if (likely(*prealloc == NULL)) {
2036 pr = __alloc_pending(nofail: false);
2037 if (!pr) {
2038 ret = -ENOMEM;
2039 goto out;
2040 }
2041 } else {
2042 pr = *prealloc;
2043 *prealloc = NULL;
2044 }
2045 pr->lclu = lclu;
2046
2047 rb_link_node(node: &pr->rb_node, parent, rb_link: p);
2048 rb_insert_color(&pr->rb_node, &tree->root);
2049 ret = 1;
2050
2051out:
2052 return ret;
2053}
2054
2055/*
2056 * __remove_pending - removes a pending cluster reservation from the set
2057 * of pending reservations
2058 *
2059 * @inode - file containing the cluster
2060 * @lblk - logical block in the pending cluster reservation to be removed
2061 *
2062 * Returns successfully if pending reservation is not a member of the set.
2063 */
2064static void __remove_pending(struct inode *inode, ext4_lblk_t lblk)
2065{
2066 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
2067 struct pending_reservation *pr;
2068 struct ext4_pending_tree *tree;
2069
2070 pr = __get_pending(inode, EXT4_B2C(sbi, lblk));
2071 if (pr != NULL) {
2072 tree = &EXT4_I(inode)->i_pending_tree;
2073 rb_erase(&pr->rb_node, &tree->root);
2074 __free_pending(pr);
2075 }
2076}
2077
2078/*
2079 * ext4_remove_pending - removes a pending cluster reservation from the set
2080 * of pending reservations
2081 *
2082 * @inode - file containing the cluster
2083 * @lblk - logical block in the pending cluster reservation to be removed
2084 *
2085 * Locking for external use of __remove_pending.
2086 */
2087void ext4_remove_pending(struct inode *inode, ext4_lblk_t lblk)
2088{
2089 struct ext4_inode_info *ei = EXT4_I(inode);
2090
2091 write_lock(&ei->i_es_lock);
2092 __remove_pending(inode, lblk);
2093 write_unlock(&ei->i_es_lock);
2094}
2095
2096/*
2097 * ext4_is_pending - determine whether a cluster has a pending reservation
2098 * on it
2099 *
2100 * @inode - file containing the cluster
2101 * @lblk - logical block in the cluster
2102 *
2103 * Returns true if there's a pending reservation for the cluster in the
2104 * set of pending reservations, and false if not.
2105 */
2106bool ext4_is_pending(struct inode *inode, ext4_lblk_t lblk)
2107{
2108 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
2109 struct ext4_inode_info *ei = EXT4_I(inode);
2110 bool ret;
2111
2112 read_lock(&ei->i_es_lock);
2113 ret = (bool)(__get_pending(inode, EXT4_B2C(sbi, lblk)) != NULL);
2114 read_unlock(&ei->i_es_lock);
2115
2116 return ret;
2117}
2118
2119/*
2120 * ext4_es_insert_delayed_extent - adds some delayed blocks to the extents
2121 * status tree, adding a pending reservation
2122 * where needed
2123 *
2124 * @inode - file containing the newly added block
2125 * @lblk - start logical block to be added
2126 * @len - length of blocks to be added
2127 * @lclu_allocated/end_allocated - indicates whether a physical cluster has
2128 * been allocated for the logical cluster
2129 * that contains the start/end block. Note that
2130 * end_allocated should always be set to false
2131 * if the start and the end block are in the
2132 * same cluster
2133 */
2134void ext4_es_insert_delayed_extent(struct inode *inode, ext4_lblk_t lblk,
2135 ext4_lblk_t len, bool lclu_allocated,
2136 bool end_allocated)
2137{
2138 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
2139 struct extent_status newes;
2140 ext4_lblk_t end = lblk + len - 1;
2141 int err1 = 0, err2 = 0, err3 = 0;
2142 struct extent_status *es1 = NULL;
2143 struct extent_status *es2 = NULL;
2144 struct pending_reservation *pr1 = NULL;
2145 struct pending_reservation *pr2 = NULL;
2146
2147 if (EXT4_SB(sb: inode->i_sb)->s_mount_state & EXT4_FC_REPLAY)
2148 return;
2149
2150 es_debug("add [%u/%u) delayed to extent status tree of inode %lu\n",
2151 lblk, len, inode->i_ino);
2152 if (!len)
2153 return;
2154
2155 WARN_ON_ONCE((EXT4_B2C(sbi, lblk) == EXT4_B2C(sbi, end)) &&
2156 end_allocated);
2157
2158 newes.es_lblk = lblk;
2159 newes.es_len = len;
2160 ext4_es_store_pblock_status(es: &newes, pb: ~0, EXTENT_STATUS_DELAYED);
2161
2162 ext4_es_insert_extent_check(inode, es: &newes);
2163
2164retry:
2165 if (err1 && !es1)
2166 es1 = __es_alloc_extent(nofail: true);
2167 if ((err1 || err2) && !es2)
2168 es2 = __es_alloc_extent(nofail: true);
2169 if (err1 || err2 || err3 < 0) {
2170 if (lclu_allocated && !pr1)
2171 pr1 = __alloc_pending(nofail: true);
2172 if (end_allocated && !pr2)
2173 pr2 = __alloc_pending(nofail: true);
2174 }
2175 write_lock(&EXT4_I(inode)->i_es_lock);
2176
2177 err1 = __es_remove_extent(inode, lblk, end, NULL, prealloc: es1);
2178 if (err1 != 0)
2179 goto error;
2180 /* Free preallocated extent if it didn't get used. */
2181 if (es1) {
2182 if (!es1->es_len)
2183 __es_free_extent(es: es1);
2184 es1 = NULL;
2185 }
2186
2187 err2 = __es_insert_extent(inode, newes: &newes, prealloc: es2);
2188 if (err2 != 0)
2189 goto error;
2190 /* Free preallocated extent if it didn't get used. */
2191 if (es2) {
2192 if (!es2->es_len)
2193 __es_free_extent(es: es2);
2194 es2 = NULL;
2195 }
2196
2197 if (lclu_allocated) {
2198 err3 = __insert_pending(inode, lblk, prealloc: &pr1);
2199 if (err3 < 0)
2200 goto error;
2201 if (pr1) {
2202 __free_pending(pr: pr1);
2203 pr1 = NULL;
2204 }
2205 }
2206 if (end_allocated) {
2207 err3 = __insert_pending(inode, lblk: end, prealloc: &pr2);
2208 if (err3 < 0)
2209 goto error;
2210 if (pr2) {
2211 __free_pending(pr: pr2);
2212 pr2 = NULL;
2213 }
2214 }
2215 ext4_es_inc_seq(inode);
2216error:
2217 write_unlock(&EXT4_I(inode)->i_es_lock);
2218 if (err1 || err2 || err3 < 0)
2219 goto retry;
2220
2221 trace_ext4_es_insert_delayed_extent(inode, es: &newes, lclu_allocated,
2222 end_allocated);
2223 ext4_es_print_tree(inode);
2224 ext4_print_pending_tree(inode);
2225 return;
2226}
2227
2228/*
2229 * __revise_pending - makes, cancels, or leaves unchanged pending cluster
2230 * reservations for a specified block range depending
2231 * upon the presence or absence of delayed blocks
2232 * outside the range within clusters at the ends of the
2233 * range
2234 *
2235 * @inode - file containing the range
2236 * @lblk - logical block defining the start of range
2237 * @len - length of range in blocks
2238 * @prealloc - preallocated pending entry
2239 *
2240 * Used after a newly allocated extent is added to the extents status tree.
2241 * Requires that the extents in the range have either written or unwritten
2242 * status. Must be called while holding i_es_lock. Returns number of new
2243 * inserts pending cluster on insert pendings, returns 0 on remove pendings,
2244 * return -ENOMEM on failure.
2245 */
2246static int __revise_pending(struct inode *inode, ext4_lblk_t lblk,
2247 ext4_lblk_t len,
2248 struct pending_reservation **prealloc)
2249{
2250 struct ext4_sb_info *sbi = EXT4_SB(sb: inode->i_sb);
2251 ext4_lblk_t end = lblk + len - 1;
2252 ext4_lblk_t first, last;
2253 bool f_del = false, l_del = false;
2254 int pendings = 0;
2255 int ret = 0;
2256
2257 if (len == 0)
2258 return 0;
2259
2260 /*
2261 * Two cases - block range within single cluster and block range
2262 * spanning two or more clusters. Note that a cluster belonging
2263 * to a range starting and/or ending on a cluster boundary is treated
2264 * as if it does not contain a delayed extent. The new range may
2265 * have allocated space for previously delayed blocks out to the
2266 * cluster boundary, requiring that any pre-existing pending
2267 * reservation be canceled. Because this code only looks at blocks
2268 * outside the range, it should revise pending reservations
2269 * correctly even if the extent represented by the range can't be
2270 * inserted in the extents status tree due to ENOSPC.
2271 */
2272
2273 if (EXT4_B2C(sbi, lblk) == EXT4_B2C(sbi, end)) {
2274 first = EXT4_LBLK_CMASK(sbi, lblk);
2275 if (first != lblk)
2276 f_del = __es_scan_range(inode, matching_fn: &ext4_es_is_delayed,
2277 start: first, end: lblk - 1);
2278 if (f_del) {
2279 ret = __insert_pending(inode, lblk: first, prealloc);
2280 if (ret < 0)
2281 goto out;
2282 pendings += ret;
2283 } else {
2284 last = EXT4_LBLK_CMASK(sbi, end) +
2285 sbi->s_cluster_ratio - 1;
2286 if (last != end)
2287 l_del = __es_scan_range(inode,
2288 matching_fn: &ext4_es_is_delayed,
2289 start: end + 1, end: last);
2290 if (l_del) {
2291 ret = __insert_pending(inode, lblk: last, prealloc);
2292 if (ret < 0)
2293 goto out;
2294 pendings += ret;
2295 } else
2296 __remove_pending(inode, lblk: last);
2297 }
2298 } else {
2299 first = EXT4_LBLK_CMASK(sbi, lblk);
2300 if (first != lblk)
2301 f_del = __es_scan_range(inode, matching_fn: &ext4_es_is_delayed,
2302 start: first, end: lblk - 1);
2303 if (f_del) {
2304 ret = __insert_pending(inode, lblk: first, prealloc);
2305 if (ret < 0)
2306 goto out;
2307 pendings += ret;
2308 } else
2309 __remove_pending(inode, lblk: first);
2310
2311 last = EXT4_LBLK_CMASK(sbi, end) + sbi->s_cluster_ratio - 1;
2312 if (last != end)
2313 l_del = __es_scan_range(inode, matching_fn: &ext4_es_is_delayed,
2314 start: end + 1, end: last);
2315 if (l_del) {
2316 ret = __insert_pending(inode, lblk: last, prealloc);
2317 if (ret < 0)
2318 goto out;
2319 pendings += ret;
2320 } else
2321 __remove_pending(inode, lblk: last);
2322 }
2323out:
2324 return (ret < 0) ? ret : pendings;
2325}
2326

source code of linux/fs/ext4/extents_status.c