1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* linux/fs/ext4/resize.c
4	*
5	* Support for resizing an ext4 filesystem while it is mounted.
6	*
7	* Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
8	*
9	* This could probably be made into a module, because it is not often in use.
10	*/
11
12
13	#include <linux/errno.h>
14	#include <linux/slab.h>
15	#include <linux/jiffies.h>
16
17	#include "ext4_jbd2.h"
18
19	struct ext4_rcu_ptr {
20	struct rcu_head rcu;
21	void *ptr;
22	};
23
24	static void ext4_rcu_ptr_callback(struct rcu_head *head)
25	{
26	struct ext4_rcu_ptr *ptr;
27
28	ptr = container_of(head, struct ext4_rcu_ptr, rcu);
29	kvfree(addr: ptr->ptr);
30	kfree(objp: ptr);
31	}
32
33	void ext4_kvfree_array_rcu(void *to_free)
34	{
35	struct ext4_rcu_ptr *ptr = kzalloc(size: sizeof(*ptr), GFP_KERNEL);
36
37	if (ptr) {
38	ptr->ptr = to_free;
39	call_rcu(head: &ptr->rcu, func: ext4_rcu_ptr_callback);
40	return;
41	}
42	synchronize_rcu();
43	kvfree(addr: to_free);
44	}
45
46	int ext4_resize_begin(struct super_block *sb)
47	{
48	struct ext4_sb_info *sbi = EXT4_SB(sb);
49	int ret = 0;
50
51	if (!capable(CAP_SYS_RESOURCE))
52	return -EPERM;
53
54	/*
55	* If the reserved GDT blocks is non-zero, the resize_inode feature
56	* should always be set.
57	*/
58	if (sbi->s_es->s_reserved_gdt_blocks &&
59	!ext4_has_feature_resize_inode(sb)) {
60	ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
61	return -EFSCORRUPTED;
62	}
63
64	/*
65	* If we are not using the primary superblock/GDT copy don't resize,
66	* because the user tools have no way of handling this. Probably a
67	* bad time to do it anyways.
68	*/
69	if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
70	le32_to_cpu(sbi->s_es->s_first_data_block)) {
71	ext4_warning(sb, "won't resize using backup superblock at %llu",
72	(unsigned long long)sbi->s_sbh->b_blocknr);
73	return -EPERM;
74	}
75
76	/*
77	* We are not allowed to do online-resizing on a filesystem mounted
78	* with error, because it can destroy the filesystem easily.
79	*/
80	if (sbi->s_mount_state & EXT4_ERROR_FS) {
81	ext4_warning(sb, "There are errors in the filesystem, "
82	"so online resizing is not allowed");
83	return -EPERM;
84	}
85
86	if (ext4_has_feature_sparse_super2(sb)) {
87	ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
88	return -EOPNOTSUPP;
89	}
90
91	if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
92	addr: &sbi->s_ext4_flags))
93	ret = -EBUSY;
94
95	return ret;
96	}
97
98	int ext4_resize_end(struct super_block *sb, bool update_backups)
99	{
100	clear_bit_unlock(EXT4_FLAGS_RESIZING, addr: &EXT4_SB(sb)->s_ext4_flags);
101	smp_mb__after_atomic();
102	if (update_backups)
103	return ext4_update_overhead(sb, force: true);
104	return 0;
105	}
106
107	static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
108	ext4_group_t group) {
109	ext4_grpblk_t overhead;
110	overhead = ext4_bg_num_gdb(sb, group);
111	if (ext4_bg_has_super(sb, group))
112	overhead += 1 +
113	le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
114	return overhead;
115	}
116
117	#define outside(b, first, last) ((b) < (first) || (b) >= (last))
118	#define inside(b, first, last) ((b) >= (first) && (b) < (last))
119
120	static int verify_group_input(struct super_block *sb,
121	struct ext4_new_group_data *input)
122	{
123	struct ext4_sb_info *sbi = EXT4_SB(sb);
124	struct ext4_super_block *es = sbi->s_es;
125	ext4_fsblk_t start = ext4_blocks_count(es);
126	ext4_fsblk_t end = start + input->blocks_count;
127	ext4_group_t group = input->group;
128	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
129	unsigned overhead;
130	ext4_fsblk_t metaend;
131	struct buffer_head *bh = NULL;
132	ext4_grpblk_t free_blocks_count, offset;
133	int err = -EINVAL;
134
135	if (group != sbi->s_groups_count) {
136	ext4_warning(sb, "Cannot add at group %u (only %u groups)",
137	input->group, sbi->s_groups_count);
138	return -EINVAL;
139	}
140
141	overhead = ext4_group_overhead_blocks(sb, group);
142	metaend = start + overhead;
143	free_blocks_count = input->blocks_count - 2 - overhead -
144	sbi->s_itb_per_group;
145	input->free_clusters_count = EXT4_B2C(sbi, free_blocks_count);
146
147	if (test_opt(sb, DEBUG))
148	printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
149	"(%d free, %u reserved)\n",
150	ext4_bg_has_super(sb, input->group) ? "normal" :
151	"no-super", input->group, input->blocks_count,
152	free_blocks_count, input->reserved_blocks);
153
154	ext4_get_group_no_and_offset(sb, blocknr: start, NULL, offsetp: &offset);
155	if (offset != 0)
156	ext4_warning(sb, "Last group not full");
157	else if (input->reserved_blocks > input->blocks_count / 5)
158	ext4_warning(sb, "Reserved blocks too high (%u)",
159	input->reserved_blocks);
160	else if (free_blocks_count < 0)
161	ext4_warning(sb, "Bad blocks count %u",
162	input->blocks_count);
163	else if (IS_ERR(ptr: bh = ext4_sb_bread(sb, block: end - 1, op_flags: 0))) {
164	err = PTR_ERR(ptr: bh);
165	bh = NULL;
166	ext4_warning(sb, "Cannot read last block (%llu)",
167	end - 1);
168	} else if (outside(input->block_bitmap, start, end))
169	ext4_warning(sb, "Block bitmap not in group (block %llu)",
170	(unsigned long long)input->block_bitmap);
171	else if (outside(input->inode_bitmap, start, end))
172	ext4_warning(sb, "Inode bitmap not in group (block %llu)",
173	(unsigned long long)input->inode_bitmap);
174	else if (outside(input->inode_table, start, end) ||
175	outside(itend - 1, start, end))
176	ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
177	(unsigned long long)input->inode_table, itend - 1);
178	else if (input->inode_bitmap == input->block_bitmap)
179	ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
180	(unsigned long long)input->block_bitmap);
181	else if (inside(input->block_bitmap, input->inode_table, itend))
182	ext4_warning(sb, "Block bitmap (%llu) in inode table "
183	"(%llu-%llu)",
184	(unsigned long long)input->block_bitmap,
185	(unsigned long long)input->inode_table, itend - 1);
186	else if (inside(input->inode_bitmap, input->inode_table, itend))
187	ext4_warning(sb, "Inode bitmap (%llu) in inode table "
188	"(%llu-%llu)",
189	(unsigned long long)input->inode_bitmap,
190	(unsigned long long)input->inode_table, itend - 1);
191	else if (inside(input->block_bitmap, start, metaend))
192	ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
193	(unsigned long long)input->block_bitmap,
194	start, metaend - 1);
195	else if (inside(input->inode_bitmap, start, metaend))
196	ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
197	(unsigned long long)input->inode_bitmap,
198	start, metaend - 1);
199	else if (inside(input->inode_table, start, metaend) ||
200	inside(itend - 1, start, metaend))
201	ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
202	"(%llu-%llu)",
203	(unsigned long long)input->inode_table,
204	itend - 1, start, metaend - 1);
205	else
206	err = 0;
207	brelse(bh);
208
209	return err;
210	}
211
212	/*
213	* ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
214	* group each time.
215	*/
216	struct ext4_new_flex_group_data {
217	struct ext4_new_group_data *groups; /* new_group_data for groups
218	in the flex group */
219	__u16 *bg_flags; /* block group flags of groups
220	in @groups */
221	ext4_group_t resize_bg; /* number of allocated
222	new_group_data */
223	ext4_group_t count; /* number of groups in @groups
224	*/
225	};
226
227	/*
228	* Avoiding memory allocation failures due to too many groups added each time.
229	*/
230	#define MAX_RESIZE_BG 16384
231
232	/*
233	* alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
234	* @flexbg_size.
235	*
236	* Returns NULL on failure otherwise address of the allocated structure.
237	*/
238	static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size,
239	ext4_group_t o_group, ext4_group_t n_group)
240	{
241	ext4_group_t last_group;
242	struct ext4_new_flex_group_data *flex_gd;
243
244	flex_gd = kmalloc(size: sizeof(*flex_gd), GFP_NOFS);
245	if (flex_gd == NULL)
246	goto out3;
247
248	if (unlikely(flexbg_size > MAX_RESIZE_BG))
249	flex_gd->resize_bg = MAX_RESIZE_BG;
250	else
251	flex_gd->resize_bg = flexbg_size;
252
253	/* Avoid allocating large 'groups' array if not needed */
254	last_group = o_group | (flex_gd->resize_bg - 1);
255	if (n_group <= last_group)
256	flex_gd->resize_bg = 1 << fls(x: n_group - o_group + 1);
257	else if (n_group - last_group < flex_gd->resize_bg)
258	flex_gd->resize_bg = 1 << max(fls(last_group - o_group + 1),
259	fls(n_group - last_group));
260
261	flex_gd->groups = kmalloc_array(n: flex_gd->resize_bg,
262	size: sizeof(struct ext4_new_group_data),
263	GFP_NOFS);
264	if (flex_gd->groups == NULL)
265	goto out2;
266
267	flex_gd->bg_flags = kmalloc_array(n: flex_gd->resize_bg, size: sizeof(__u16),
268	GFP_NOFS);
269	if (flex_gd->bg_flags == NULL)
270	goto out1;
271
272	return flex_gd;
273
274	out1:
275	kfree(objp: flex_gd->groups);
276	out2:
277	kfree(objp: flex_gd);
278	out3:
279	return NULL;
280	}
281
282	static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
283	{
284	kfree(objp: flex_gd->bg_flags);
285	kfree(objp: flex_gd->groups);
286	kfree(objp: flex_gd);
287	}
288
289	/*
290	* ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
291	* and inode tables for a flex group.
292	*
293	* This function is used by 64bit-resize. Note that this function allocates
294	* group tables from the 1st group of groups contained by @flexgd, which may
295	* be a partial of a flex group.
296	*
297	* @sb: super block of fs to which the groups belongs
298	*
299	* Returns 0 on a successful allocation of the metadata blocks in the
300	* block group.
301	*/
302	static int ext4_alloc_group_tables(struct super_block *sb,
303	struct ext4_new_flex_group_data *flex_gd,
304	unsigned int flexbg_size)
305	{
306	struct ext4_new_group_data *group_data = flex_gd->groups;
307	ext4_fsblk_t start_blk;
308	ext4_fsblk_t last_blk;
309	ext4_group_t src_group;
310	ext4_group_t bb_index = 0;
311	ext4_group_t ib_index = 0;
312	ext4_group_t it_index = 0;
313	ext4_group_t group;
314	ext4_group_t last_group;
315	unsigned overhead;
316	__u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
317	int i;
318
319	BUG_ON(flex_gd->count == 0 || group_data == NULL);
320
321	src_group = group_data[0].group;
322	last_group = src_group + flex_gd->count - 1;
323
324	BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
325	(last_group & ~(flexbg_size - 1))));
326	next_group:
327	group = group_data[0].group;
328	if (src_group >= group_data[0].group + flex_gd->count)
329	return -ENOSPC;
330	start_blk = ext4_group_first_block_no(sb, group_no: src_group);
331	last_blk = start_blk + group_data[src_group - group].blocks_count;
332
333	overhead = ext4_group_overhead_blocks(sb, group: src_group);
334
335	start_blk += overhead;
336
337	/* We collect contiguous blocks as much as possible. */
338	src_group++;
339	for (; src_group <= last_group; src_group++) {
340	overhead = ext4_group_overhead_blocks(sb, group: src_group);
341	if (overhead == 0)
342	last_blk += group_data[src_group - group].blocks_count;
343	else
344	break;
345	}
346
347	/* Allocate block bitmaps */
348	for (; bb_index < flex_gd->count; bb_index++) {
349	if (start_blk >= last_blk)
350	goto next_group;
351	group_data[bb_index].block_bitmap = start_blk++;
352	group = ext4_get_group_number(sb, block: start_blk - 1);
353	group -= group_data[0].group;
354	group_data[group].mdata_blocks++;
355	flex_gd->bg_flags[group] &= uninit_mask;
356	}
357
358	/* Allocate inode bitmaps */
359	for (; ib_index < flex_gd->count; ib_index++) {
360	if (start_blk >= last_blk)
361	goto next_group;
362	group_data[ib_index].inode_bitmap = start_blk++;
363	group = ext4_get_group_number(sb, block: start_blk - 1);
364	group -= group_data[0].group;
365	group_data[group].mdata_blocks++;
366	flex_gd->bg_flags[group] &= uninit_mask;
367	}
368
369	/* Allocate inode tables */
370	for (; it_index < flex_gd->count; it_index++) {
371	unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
372	ext4_fsblk_t next_group_start;
373
374	if (start_blk + itb > last_blk)
375	goto next_group;
376	group_data[it_index].inode_table = start_blk;
377	group = ext4_get_group_number(sb, block: start_blk);
378	next_group_start = ext4_group_first_block_no(sb, group_no: group + 1);
379	group -= group_data[0].group;
380
381	if (start_blk + itb > next_group_start) {
382	flex_gd->bg_flags[group + 1] &= uninit_mask;
383	overhead = start_blk + itb - next_group_start;
384	group_data[group + 1].mdata_blocks += overhead;
385	itb -= overhead;
386	}
387
388	group_data[group].mdata_blocks += itb;
389	flex_gd->bg_flags[group] &= uninit_mask;
390	start_blk += EXT4_SB(sb)->s_itb_per_group;
391	}
392
393	/* Update free clusters count to exclude metadata blocks */
394	for (i = 0; i < flex_gd->count; i++) {
395	group_data[i].free_clusters_count -=
396	EXT4_NUM_B2C(EXT4_SB(sb),
397	group_data[i].mdata_blocks);
398	}
399
400	if (test_opt(sb, DEBUG)) {
401	int i;
402	group = group_data[0].group;
403
404	printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
405	"%u groups, flexbg size is %u:\n", flex_gd->count,
406	flexbg_size);
407
408	for (i = 0; i < flex_gd->count; i++) {
409	ext4_debug(
410	"adding %s group %u: %u blocks (%u free, %u mdata blocks)\n",
411	ext4_bg_has_super(sb, group + i) ? "normal" :
412	"no-super", group + i,
413	group_data[i].blocks_count,
414	group_data[i].free_clusters_count,
415	group_data[i].mdata_blocks);
416	}
417	}
418	return 0;
419	}
420
421	static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
422	ext4_fsblk_t blk)
423	{
424	struct buffer_head *bh;
425	int err;
426
427	bh = sb_getblk(sb, block: blk);
428	if (unlikely(!bh))
429	return ERR_PTR(error: -ENOMEM);
430	BUFFER_TRACE(bh, "get_write_access");
431	err = ext4_journal_get_write_access(handle, sb, bh, EXT4_JTR_NONE);
432	if (err) {
433	brelse(bh);
434	bh = ERR_PTR(error: err);
435	} else {
436	memset(bh->b_data, 0, sb->s_blocksize);
437	set_buffer_uptodate(bh);
438	}
439
440	return bh;
441	}
442
443	static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
444	{
445	return ext4_journal_ensure_credits_fn(handle, credits,
446	EXT4_MAX_TRANS_DATA, 0, 0);
447	}
448
449	/*
450	* set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
451	*
452	* Helper function for ext4_setup_new_group_blocks() which set .
453	*
454	* @sb: super block
455	* @handle: journal handle
456	* @flex_gd: flex group data
457	*/
458	static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
459	struct ext4_new_flex_group_data *flex_gd,
460	ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
461	{
462	struct ext4_sb_info *sbi = EXT4_SB(sb);
463	ext4_group_t count = last_cluster - first_cluster + 1;
464	ext4_group_t count2;
465
466	ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
467	last_cluster);
468	for (; count > 0; count -= count2, first_cluster += count2) {
469	ext4_fsblk_t start;
470	struct buffer_head *bh;
471	ext4_group_t group;
472	int err;
473
474	group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
475	start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
476	group -= flex_gd->groups[0].group;
477
478	count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
479	if (count2 > count)
480	count2 = count;
481
482	if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
483	BUG_ON(flex_gd->count > 1);
484	continue;
485	}
486
487	err = ext4_resize_ensure_credits_batch(handle, credits: 1);
488	if (err < 0)
489	return err;
490
491	bh = sb_getblk(sb, block: flex_gd->groups[group].block_bitmap);
492	if (unlikely(!bh))
493	return -ENOMEM;
494
495	BUFFER_TRACE(bh, "get_write_access");
496	err = ext4_journal_get_write_access(handle, sb, bh,
497	EXT4_JTR_NONE);
498	if (err) {
499	brelse(bh);
500	return err;
501	}
502	ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
503	first_cluster, first_cluster - start, count2);
504	mb_set_bits(bm: bh->b_data, cur: first_cluster - start, len: count2);
505
506	err = ext4_handle_dirty_metadata(handle, NULL, bh);
507	brelse(bh);
508	if (unlikely(err))
509	return err;
510	}
511
512	return 0;
513	}
514
515	/*
516	* Set up the block and inode bitmaps, and the inode table for the new groups.
517	* This doesn't need to be part of the main transaction, since we are only
518	* changing blocks outside the actual filesystem. We still do journaling to
519	* ensure the recovery is correct in case of a failure just after resize.
520	* If any part of this fails, we simply abort the resize.
521	*
522	* setup_new_flex_group_blocks handles a flex group as follow:
523	* 1. copy super block and GDT, and initialize group tables if necessary.
524	* In this step, we only set bits in blocks bitmaps for blocks taken by
525	* super block and GDT.
526	* 2. allocate group tables in block bitmaps, that is, set bits in block
527	* bitmap for blocks taken by group tables.
528	*/
529	static int setup_new_flex_group_blocks(struct super_block *sb,
530	struct ext4_new_flex_group_data *flex_gd)
531	{
532	int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
533	ext4_fsblk_t start;
534	ext4_fsblk_t block;
535	struct ext4_sb_info *sbi = EXT4_SB(sb);
536	struct ext4_super_block *es = sbi->s_es;
537	struct ext4_new_group_data *group_data = flex_gd->groups;
538	__u16 *bg_flags = flex_gd->bg_flags;
539	handle_t *handle;
540	ext4_group_t group, count;
541	struct buffer_head *bh = NULL;
542	int reserved_gdb, i, j, err = 0, err2;
543	int meta_bg;
544
545	BUG_ON(!flex_gd->count || !group_data ||
546	group_data[0].group != sbi->s_groups_count);
547
548	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
549	meta_bg = ext4_has_feature_meta_bg(sb);
550
551	/* This transaction may be extended/restarted along the way */
552	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
553	if (IS_ERR(ptr: handle))
554	return PTR_ERR(ptr: handle);
555
556	group = group_data[0].group;
557	for (i = 0; i < flex_gd->count; i++, group++) {
558	unsigned long gdblocks;
559	ext4_grpblk_t overhead;
560
561	gdblocks = ext4_bg_num_gdb(sb, group);
562	start = ext4_group_first_block_no(sb, group_no: group);
563
564	if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
565	goto handle_itb;
566
567	if (meta_bg == 1)
568	goto handle_itb;
569
570	block = start + ext4_bg_has_super(sb, group);
571	/* Copy all of the GDT blocks into the backup in this group */
572	for (j = 0; j < gdblocks; j++, block++) {
573	struct buffer_head *gdb;
574
575	ext4_debug("update backup group %#04llx\n", block);
576	err = ext4_resize_ensure_credits_batch(handle, credits: 1);
577	if (err < 0)
578	goto out;
579
580	gdb = sb_getblk(sb, block);
581	if (unlikely(!gdb)) {
582	err = -ENOMEM;
583	goto out;
584	}
585
586	BUFFER_TRACE(gdb, "get_write_access");
587	err = ext4_journal_get_write_access(handle, sb, gdb,
588	EXT4_JTR_NONE);
589	if (err) {
590	brelse(bh: gdb);
591	goto out;
592	}
593	memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
594	s_group_desc, j)->b_data, gdb->b_size);
595	set_buffer_uptodate(gdb);
596
597	err = ext4_handle_dirty_metadata(handle, NULL, gdb);
598	if (unlikely(err)) {
599	brelse(bh: gdb);
600	goto out;
601	}
602	brelse(bh: gdb);
603	}
604
605	/* Zero out all of the reserved backup group descriptor
606	* table blocks
607	*/
608	if (ext4_bg_has_super(sb, group)) {
609	err = sb_issue_zeroout(sb, block: gdblocks + start + 1,
610	nr_blocks: reserved_gdb, GFP_NOFS);
611	if (err)
612	goto out;
613	}
614
615	handle_itb:
616	/* Initialize group tables of the group @group */
617	if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
618	goto handle_bb;
619
620	/* Zero out all of the inode table blocks */
621	block = group_data[i].inode_table;
622	ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
623	block, sbi->s_itb_per_group);
624	err = sb_issue_zeroout(sb, block, nr_blocks: sbi->s_itb_per_group,
625	GFP_NOFS);
626	if (err)
627	goto out;
628
629	handle_bb:
630	if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
631	goto handle_ib;
632
633	/* Initialize block bitmap of the @group */
634	block = group_data[i].block_bitmap;
635	err = ext4_resize_ensure_credits_batch(handle, credits: 1);
636	if (err < 0)
637	goto out;
638
639	bh = bclean(handle, sb, blk: block);
640	if (IS_ERR(ptr: bh)) {
641	err = PTR_ERR(ptr: bh);
642	goto out;
643	}
644	overhead = ext4_group_overhead_blocks(sb, group);
645	if (overhead != 0) {
646	ext4_debug("mark backup superblock %#04llx (+0)\n",
647	start);
648	mb_set_bits(bm: bh->b_data, cur: 0,
649	EXT4_NUM_B2C(sbi, overhead));
650	}
651	ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
652	end_bit: sb->s_blocksize * 8, bitmap: bh->b_data);
653	err = ext4_handle_dirty_metadata(handle, NULL, bh);
654	brelse(bh);
655	if (err)
656	goto out;
657
658	handle_ib:
659	if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
660	continue;
661
662	/* Initialize inode bitmap of the @group */
663	block = group_data[i].inode_bitmap;
664	err = ext4_resize_ensure_credits_batch(handle, credits: 1);
665	if (err < 0)
666	goto out;
667	/* Mark unused entries in inode bitmap used */
668	bh = bclean(handle, sb, blk: block);
669	if (IS_ERR(ptr: bh)) {
670	err = PTR_ERR(ptr: bh);
671	goto out;
672	}
673
674	ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
675	end_bit: sb->s_blocksize * 8, bitmap: bh->b_data);
676	err = ext4_handle_dirty_metadata(handle, NULL, bh);
677	brelse(bh);
678	if (err)
679	goto out;
680	}
681
682	/* Mark group tables in block bitmap */
683	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
684	count = group_table_count[j];
685	start = (&group_data[0].block_bitmap)[j];
686	block = start;
687	for (i = 1; i < flex_gd->count; i++) {
688	block += group_table_count[j];
689	if (block == (&group_data[i].block_bitmap)[j]) {
690	count += group_table_count[j];
691	continue;
692	}
693	err = set_flexbg_block_bitmap(sb, handle,
694	flex_gd,
695	EXT4_B2C(sbi, start),
696	EXT4_B2C(sbi,
697	start + count
698	- 1));
699	if (err)
700	goto out;
701	count = group_table_count[j];
702	start = (&group_data[i].block_bitmap)[j];
703	block = start;
704	}
705
706	err = set_flexbg_block_bitmap(sb, handle,
707	flex_gd,
708	EXT4_B2C(sbi, start),
709	EXT4_B2C(sbi,
710	start + count
711	- 1));
712	if (err)
713	goto out;
714	}
715
716	out:
717	err2 = ext4_journal_stop(handle);
718	if (err2 && !err)
719	err = err2;
720
721	return err;
722	}
723
724	/*
725	* Iterate through the groups which hold BACKUP superblock/GDT copies in an
726	* ext4 filesystem. The counters should be initialized to 1, 5, and 7 before
727	* calling this for the first time. In a sparse filesystem it will be the
728	* sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
729	* For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
730	*/
731	unsigned int ext4_list_backups(struct super_block *sb, unsigned int *three,
732	unsigned int *five, unsigned int *seven)
733	{
734	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
735	unsigned int *min = three;
736	int mult = 3;
737	unsigned int ret;
738
739	if (ext4_has_feature_sparse_super2(sb)) {
740	do {
741	if (*min > 2)
742	return UINT_MAX;
743	ret = le32_to_cpu(es->s_backup_bgs[*min - 1]);
744	*min += 1;
745	} while (!ret);
746	return ret;
747	}
748
749	if (!ext4_has_feature_sparse_super(sb)) {
750	ret = *min;
751	*min += 1;
752	return ret;
753	}
754
755	if (*five < *min) {
756	min = five;
757	mult = 5;
758	}
759	if (*seven < *min) {
760	min = seven;
761	mult = 7;
762	}
763
764	ret = *min;
765	*min *= mult;
766
767	return ret;
768	}
769
770	/*
771	* Check that all of the backup GDT blocks are held in the primary GDT block.
772	* It is assumed that they are stored in group order. Returns the number of
773	* groups in current filesystem that have BACKUPS, or -ve error code.
774	*/
775	static int verify_reserved_gdb(struct super_block *sb,
776	ext4_group_t end,
777	struct buffer_head *primary)
778	{
779	const ext4_fsblk_t blk = primary->b_blocknr;
780	unsigned three = 1;
781	unsigned five = 5;
782	unsigned seven = 7;
783	unsigned grp;
784	__le32 *p = (__le32 *)primary->b_data;
785	int gdbackups = 0;
786
787	while ((grp = ext4_list_backups(sb, three: &three, five: &five, seven: &seven)) < end) {
788	if (le32_to_cpu(*p++) !=
789	grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
790	ext4_warning(sb, "reserved GDT %llu"
791	" missing grp %d (%llu)",
792	blk, grp,
793	grp *
794	(ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
795	blk);
796	return -EINVAL;
797	}
798	if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
799	return -EFBIG;
800	}
801
802	return gdbackups;
803	}
804
805	/*
806	* Called when we need to bring a reserved group descriptor table block into
807	* use from the resize inode. The primary copy of the new GDT block currently
808	* is an indirect block (under the double indirect block in the resize inode).
809	* The new backup GDT blocks will be stored as leaf blocks in this indirect
810	* block, in group order. Even though we know all the block numbers we need,
811	* we check to ensure that the resize inode has actually reserved these blocks.
812	*
813	* Don't need to update the block bitmaps because the blocks are still in use.
814	*
815	* We get all of the error cases out of the way, so that we are sure to not
816	* fail once we start modifying the data on disk, because JBD has no rollback.
817	*/
818	static int add_new_gdb(handle_t *handle, struct inode *inode,
819	ext4_group_t group)
820	{
821	struct super_block *sb = inode->i_sb;
822	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
823	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
824	ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
825	struct buffer_head **o_group_desc, **n_group_desc = NULL;
826	struct buffer_head *dind = NULL;
827	struct buffer_head *gdb_bh = NULL;
828	int gdbackups;
829	struct ext4_iloc iloc = { .bh = NULL };
830	__le32 *data;
831	int err;
832
833	if (test_opt(sb, DEBUG))
834	printk(KERN_DEBUG
835	"EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
836	gdb_num);
837
838	gdb_bh = ext4_sb_bread(sb, block: gdblock, op_flags: 0);
839	if (IS_ERR(ptr: gdb_bh))
840	return PTR_ERR(ptr: gdb_bh);
841
842	gdbackups = verify_reserved_gdb(sb, end: group, primary: gdb_bh);
843	if (gdbackups < 0) {
844	err = gdbackups;
845	goto errout;
846	}
847
848	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
849	dind = ext4_sb_bread(sb, le32_to_cpu(*data), op_flags: 0);
850	if (IS_ERR(ptr: dind)) {
851	err = PTR_ERR(ptr: dind);
852	dind = NULL;
853	goto errout;
854	}
855
856	data = (__le32 *)dind->b_data;
857	if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
858	ext4_warning(sb, "new group %u GDT block %llu not reserved",
859	group, gdblock);
860	err = -EINVAL;
861	goto errout;
862	}
863
864	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
865	err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
866	EXT4_JTR_NONE);
867	if (unlikely(err))
868	goto errout;
869
870	BUFFER_TRACE(gdb_bh, "get_write_access");
871	err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
872	if (unlikely(err))
873	goto errout;
874
875	BUFFER_TRACE(dind, "get_write_access");
876	err = ext4_journal_get_write_access(handle, sb, dind, EXT4_JTR_NONE);
877	if (unlikely(err)) {
878	ext4_std_error(sb, err);
879	goto errout;
880	}
881
882	/* ext4_reserve_inode_write() gets a reference on the iloc */
883	err = ext4_reserve_inode_write(handle, inode, iloc: &iloc);
884	if (unlikely(err))
885	goto errout;
886
887	n_group_desc = kvmalloc(size: (gdb_num + 1) * sizeof(struct buffer_head *),
888	GFP_KERNEL);
889	if (!n_group_desc) {
890	err = -ENOMEM;
891	ext4_warning(sb, "not enough memory for %lu groups",
892	gdb_num + 1);
893	goto errout;
894	}
895
896	/*
897	* Finally, we have all of the possible failures behind us...
898	*
899	* Remove new GDT block from inode double-indirect block and clear out
900	* the new GDT block for use (which also "frees" the backup GDT blocks
901	* from the reserved inode). We don't need to change the bitmaps for
902	* these blocks, because they are marked as in-use from being in the
903	* reserved inode, and will become GDT blocks (primary and backup).
904	*/
905	data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
906	err = ext4_handle_dirty_metadata(handle, NULL, dind);
907	if (unlikely(err)) {
908	ext4_std_error(sb, err);
909	goto errout;
910	}
911	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
912	(9 - EXT4_SB(sb)->s_cluster_bits);
913	ext4_mark_iloc_dirty(handle, inode, iloc: &iloc);
914	memset(gdb_bh->b_data, 0, sb->s_blocksize);
915	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
916	if (unlikely(err)) {
917	ext4_std_error(sb, err);
918	iloc.bh = NULL;
919	goto errout;
920	}
921	brelse(bh: dind);
922
923	rcu_read_lock();
924	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
925	memcpy(n_group_desc, o_group_desc,
926	EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
927	rcu_read_unlock();
928	n_group_desc[gdb_num] = gdb_bh;
929	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
930	EXT4_SB(sb)->s_gdb_count++;
931	ext4_kvfree_array_rcu(to_free: o_group_desc);
932
933	lock_buffer(bh: EXT4_SB(sb)->s_sbh);
934	le16_add_cpu(var: &es->s_reserved_gdt_blocks, val: -1);
935	ext4_superblock_csum_set(sb);
936	unlock_buffer(bh: EXT4_SB(sb)->s_sbh);
937	err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
938	if (err)
939	ext4_std_error(sb, err);
940	return err;
941	errout:
942	kvfree(addr: n_group_desc);
943	brelse(bh: iloc.bh);
944	brelse(bh: dind);
945	brelse(bh: gdb_bh);
946
947	ext4_debug("leaving with error %d\n", err);
948	return err;
949	}
950
951	/*
952	* If there is no available space in the existing block group descriptors for
953	* the new block group and there are no reserved block group descriptors, then
954	* the meta_bg feature will get enabled, and es->s_first_meta_bg will get set
955	* to the first block group that is managed using meta_bg and s_first_meta_bg
956	* must be a multiple of EXT4_DESC_PER_BLOCK(sb).
957	* This function will be called when first group of meta_bg is added to bring
958	* new group descriptors block of new added meta_bg.
959	*/
960	static int add_new_gdb_meta_bg(struct super_block *sb,
961	handle_t *handle, ext4_group_t group) {
962	ext4_fsblk_t gdblock;
963	struct buffer_head *gdb_bh;
964	struct buffer_head **o_group_desc, **n_group_desc;
965	unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
966	int err;
967
968	gdblock = ext4_group_first_block_no(sb, group_no: group) +
969	ext4_bg_has_super(sb, group);
970	gdb_bh = ext4_sb_bread(sb, block: gdblock, op_flags: 0);
971	if (IS_ERR(ptr: gdb_bh))
972	return PTR_ERR(ptr: gdb_bh);
973	n_group_desc = kvmalloc(size: (gdb_num + 1) * sizeof(struct buffer_head *),
974	GFP_KERNEL);
975	if (!n_group_desc) {
976	brelse(bh: gdb_bh);
977	err = -ENOMEM;
978	ext4_warning(sb, "not enough memory for %lu groups",
979	gdb_num + 1);
980	return err;
981	}
982
983	rcu_read_lock();
984	o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
985	memcpy(n_group_desc, o_group_desc,
986	EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
987	rcu_read_unlock();
988	n_group_desc[gdb_num] = gdb_bh;
989
990	BUFFER_TRACE(gdb_bh, "get_write_access");
991	err = ext4_journal_get_write_access(handle, sb, gdb_bh, EXT4_JTR_NONE);
992	if (err) {
993	kvfree(addr: n_group_desc);
994	brelse(bh: gdb_bh);
995	return err;
996	}
997
998	rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
999	EXT4_SB(sb)->s_gdb_count++;
1000	ext4_kvfree_array_rcu(to_free: o_group_desc);
1001	return err;
1002	}
1003
1004	/*
1005	* Called when we are adding a new group which has a backup copy of each of
1006	* the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
1007	* We need to add these reserved backup GDT blocks to the resize inode, so
1008	* that they are kept for future resizing and not allocated to files.
1009	*
1010	* Each reserved backup GDT block will go into a different indirect block.
1011	* The indirect blocks are actually the primary reserved GDT blocks,
1012	* so we know in advance what their block numbers are. We only get the
1013	* double-indirect block to verify it is pointing to the primary reserved
1014	* GDT blocks so we don't overwrite a data block by accident. The reserved
1015	* backup GDT blocks are stored in their reserved primary GDT block.
1016	*/
1017	static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
1018	ext4_group_t group)
1019	{
1020	struct super_block *sb = inode->i_sb;
1021	int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1022	int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1023	struct buffer_head **primary;
1024	struct buffer_head *dind;
1025	struct ext4_iloc iloc;
1026	ext4_fsblk_t blk;
1027	__le32 *data, *end;
1028	int gdbackups = 0;
1029	int res, i;
1030	int err;
1031
1032	primary = kmalloc_array(n: reserved_gdb, size: sizeof(*primary), GFP_NOFS);
1033	if (!primary)
1034	return -ENOMEM;
1035
1036	data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1037	dind = ext4_sb_bread(sb, le32_to_cpu(*data), op_flags: 0);
1038	if (IS_ERR(ptr: dind)) {
1039	err = PTR_ERR(ptr: dind);
1040	dind = NULL;
1041	goto exit_free;
1042	}
1043
1044	blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1045	data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1046	EXT4_ADDR_PER_BLOCK(sb));
1047	end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1048
1049	/* Get each reserved primary GDT block and verify it holds backups */
1050	for (res = 0; res < reserved_gdb; res++, blk++) {
1051	if (le32_to_cpu(*data) != blk) {
1052	ext4_warning(sb, "reserved block %llu"
1053	" not at offset %ld",
1054	blk,
1055	(long)(data - (__le32 *)dind->b_data));
1056	err = -EINVAL;
1057	goto exit_bh;
1058	}
1059	primary[res] = ext4_sb_bread(sb, block: blk, op_flags: 0);
1060	if (IS_ERR(ptr: primary[res])) {
1061	err = PTR_ERR(ptr: primary[res]);
1062	primary[res] = NULL;
1063	goto exit_bh;
1064	}
1065	gdbackups = verify_reserved_gdb(sb, end: group, primary: primary[res]);
1066	if (gdbackups < 0) {
1067	brelse(bh: primary[res]);
1068	err = gdbackups;
1069	goto exit_bh;
1070	}
1071	if (++data >= end)
1072	data = (__le32 *)dind->b_data;
1073	}
1074
1075	for (i = 0; i < reserved_gdb; i++) {
1076	BUFFER_TRACE(primary[i], "get_write_access");
1077	if ((err = ext4_journal_get_write_access(handle, sb, primary[i],
1078	EXT4_JTR_NONE)))
1079	goto exit_bh;
1080	}
1081
1082	if ((err = ext4_reserve_inode_write(handle, inode, iloc: &iloc)))
1083	goto exit_bh;
1084
1085	/*
1086	* Finally we can add each of the reserved backup GDT blocks from
1087	* the new group to its reserved primary GDT block.
1088	*/
1089	blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1090	for (i = 0; i < reserved_gdb; i++) {
1091	int err2;
1092	data = (__le32 *)primary[i]->b_data;
1093	data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1094	err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1095	if (!err)
1096	err = err2;
1097	}
1098
1099	inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1100	ext4_mark_iloc_dirty(handle, inode, iloc: &iloc);
1101
1102	exit_bh:
1103	while (--res >= 0)
1104	brelse(bh: primary[res]);
1105	brelse(bh: dind);
1106
1107	exit_free:
1108	kfree(objp: primary);
1109
1110	return err;
1111	}
1112
1113	static inline void ext4_set_block_group_nr(struct super_block *sb, char *data,
1114	ext4_group_t group)
1115	{
1116	struct ext4_super_block *es = (struct ext4_super_block *) data;
1117
1118	es->s_block_group_nr = cpu_to_le16(group);
1119	if (ext4_has_metadata_csum(sb))
1120	es->s_checksum = ext4_superblock_csum(sb, es);
1121	}
1122
1123	/*
1124	* Update the backup copies of the ext4 metadata. These don't need to be part
1125	* of the main resize transaction, because e2fsck will re-write them if there
1126	* is a problem (basically only OOM will cause a problem). However, we
1127	* _should_ update the backups if possible, in case the primary gets trashed
1128	* for some reason and we need to run e2fsck from a backup superblock. The
1129	* important part is that the new block and inode counts are in the backup
1130	* superblocks, and the location of the new group metadata in the GDT backups.
1131	*
1132	* We do not need take the s_resize_lock for this, because these
1133	* blocks are not otherwise touched by the filesystem code when it is
1134	* mounted. We don't need to worry about last changing from
1135	* sbi->s_groups_count, because the worst that can happen is that we
1136	* do not copy the full number of backups at this time. The resize
1137	* which changed s_groups_count will backup again.
1138	*/
1139	static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1140	int size, int meta_bg)
1141	{
1142	struct ext4_sb_info *sbi = EXT4_SB(sb);
1143	ext4_group_t last;
1144	const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1145	unsigned three = 1;
1146	unsigned five = 5;
1147	unsigned seven = 7;
1148	ext4_group_t group = 0;
1149	int rest = sb->s_blocksize - size;
1150	handle_t *handle;
1151	int err = 0, err2;
1152
1153	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1154	if (IS_ERR(ptr: handle)) {
1155	group = 1;
1156	err = PTR_ERR(ptr: handle);
1157	goto exit_err;
1158	}
1159
1160	if (meta_bg == 0) {
1161	group = ext4_list_backups(sb, three: &three, five: &five, seven: &seven);
1162	last = sbi->s_groups_count;
1163	} else {
1164	group = ext4_get_group_number(sb, block: blk_off) + 1;
1165	last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1166	}
1167
1168	while (group < sbi->s_groups_count) {
1169	struct buffer_head *bh;
1170	ext4_fsblk_t backup_block;
1171	int has_super = ext4_bg_has_super(sb, group);
1172	ext4_fsblk_t first_block = ext4_group_first_block_no(sb, group_no: group);
1173
1174	/* Out of journal space, and can't get more - abort - so sad */
1175	err = ext4_resize_ensure_credits_batch(handle, credits: 1);
1176	if (err < 0)
1177	break;
1178
1179	if (meta_bg == 0)
1180	backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1181	else
1182	backup_block = first_block + has_super;
1183
1184	bh = sb_getblk(sb, block: backup_block);
1185	if (unlikely(!bh)) {
1186	err = -ENOMEM;
1187	break;
1188	}
1189	ext4_debug("update metadata backup %llu(+%llu)\n",
1190	backup_block, backup_block -
1191	ext4_group_first_block_no(sb, group));
1192	BUFFER_TRACE(bh, "get_write_access");
1193	if ((err = ext4_journal_get_write_access(handle, sb, bh,
1194	EXT4_JTR_NONE))) {
1195	brelse(bh);
1196	break;
1197	}
1198	lock_buffer(bh);
1199	memcpy(bh->b_data, data, size);
1200	if (rest)
1201	memset(bh->b_data + size, 0, rest);
1202	if (has_super && (backup_block == first_block))
1203	ext4_set_block_group_nr(sb, data: bh->b_data, group);
1204	set_buffer_uptodate(bh);
1205	unlock_buffer(bh);
1206	err = ext4_handle_dirty_metadata(handle, NULL, bh);
1207	if (unlikely(err))
1208	ext4_std_error(sb, err);
1209	brelse(bh);
1210
1211	if (meta_bg == 0)
1212	group = ext4_list_backups(sb, three: &three, five: &five, seven: &seven);
1213	else if (group == last)
1214	break;
1215	else
1216	group = last;
1217	}
1218	if ((err2 = ext4_journal_stop(handle)) && !err)
1219	err = err2;
1220
1221	/*
1222	* Ugh! Need to have e2fsck write the backup copies. It is too
1223	* late to revert the resize, we shouldn't fail just because of
1224	* the backup copies (they are only needed in case of corruption).
1225	*
1226	* However, if we got here we have a journal problem too, so we
1227	* can't really start a transaction to mark the superblock.
1228	* Chicken out and just set the flag on the hope it will be written
1229	* to disk, and if not - we will simply wait until next fsck.
1230	*/
1231	exit_err:
1232	if (err) {
1233	ext4_warning(sb, "can't update backup for group %u (err %d), "
1234	"forcing fsck on next reboot", group, err);
1235	sbi->s_mount_state &= ~EXT4_VALID_FS;
1236	sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1237	mark_buffer_dirty(bh: sbi->s_sbh);
1238	}
1239	}
1240
1241	/*
1242	* ext4_add_new_descs() adds @count group descriptor of groups
1243	* starting at @group
1244	*
1245	* @handle: journal handle
1246	* @sb: super block
1247	* @group: the group no. of the first group desc to be added
1248	* @resize_inode: the resize inode
1249	* @count: number of group descriptors to be added
1250	*/
1251	static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1252	ext4_group_t group, struct inode *resize_inode,
1253	ext4_group_t count)
1254	{
1255	struct ext4_sb_info *sbi = EXT4_SB(sb);
1256	struct ext4_super_block *es = sbi->s_es;
1257	struct buffer_head *gdb_bh;
1258	int i, gdb_off, gdb_num, err = 0;
1259	int meta_bg;
1260
1261	meta_bg = ext4_has_feature_meta_bg(sb);
1262	for (i = 0; i < count; i++, group++) {
1263	int reserved_gdb = ext4_bg_has_super(sb, group) ?
1264	le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1265
1266	gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1267	gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1268
1269	/*
1270	* We will only either add reserved group blocks to a backup group
1271	* or remove reserved blocks for the first group in a new group block.
1272	* Doing both would be mean more complex code, and sane people don't
1273	* use non-sparse filesystems anymore. This is already checked above.
1274	*/
1275	if (gdb_off) {
1276	gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1277	gdb_num);
1278	BUFFER_TRACE(gdb_bh, "get_write_access");
1279	err = ext4_journal_get_write_access(handle, sb, gdb_bh,
1280	EXT4_JTR_NONE);
1281
1282	if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1283	err = reserve_backup_gdb(handle, inode: resize_inode, group);
1284	} else if (meta_bg != 0) {
1285	err = add_new_gdb_meta_bg(sb, handle, group);
1286	} else {
1287	err = add_new_gdb(handle, inode: resize_inode, group);
1288	}
1289	if (err)
1290	break;
1291	}
1292	return err;
1293	}
1294
1295	static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1296	{
1297	struct buffer_head *bh = sb_getblk(sb, block);
1298	if (unlikely(!bh))
1299	return NULL;
1300	if (!bh_uptodate_or_lock(bh)) {
1301	if (ext4_read_bh(bh, op_flags: 0, NULL) < 0) {
1302	brelse(bh);
1303	return NULL;
1304	}
1305	}
1306
1307	return bh;
1308	}
1309
1310	static int ext4_set_bitmap_checksums(struct super_block *sb,
1311	struct ext4_group_desc *gdp,
1312	struct ext4_new_group_data *group_data)
1313	{
1314	struct buffer_head *bh;
1315
1316	if (!ext4_has_metadata_csum(sb))
1317	return 0;
1318
1319	bh = ext4_get_bitmap(sb, block: group_data->inode_bitmap);
1320	if (!bh)
1321	return -EIO;
1322	ext4_inode_bitmap_csum_set(sb, gdp, bh,
1323	EXT4_INODES_PER_GROUP(sb) / 8);
1324	brelse(bh);
1325
1326	bh = ext4_get_bitmap(sb, block: group_data->block_bitmap);
1327	if (!bh)
1328	return -EIO;
1329	ext4_block_bitmap_csum_set(sb, gdp, bh);
1330	brelse(bh);
1331
1332	return 0;
1333	}
1334
1335	/*
1336	* ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1337	*/
1338	static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1339	struct ext4_new_flex_group_data *flex_gd)
1340	{
1341	struct ext4_new_group_data *group_data = flex_gd->groups;
1342	struct ext4_group_desc *gdp;
1343	struct ext4_sb_info *sbi = EXT4_SB(sb);
1344	struct buffer_head *gdb_bh;
1345	ext4_group_t group;
1346	__u16 *bg_flags = flex_gd->bg_flags;
1347	int i, gdb_off, gdb_num, err = 0;
1348
1349
1350	for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1351	group = group_data->group;
1352
1353	gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1354	gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1355
1356	/*
1357	* get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1358	*/
1359	gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1360	/* Update group descriptor block for new group */
1361	gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1362	gdb_off * EXT4_DESC_SIZE(sb));
1363
1364	memset(gdp, 0, EXT4_DESC_SIZE(sb));
1365	ext4_block_bitmap_set(sb, bg: gdp, blk: group_data->block_bitmap);
1366	ext4_inode_bitmap_set(sb, bg: gdp, blk: group_data->inode_bitmap);
1367	err = ext4_set_bitmap_checksums(sb, gdp, group_data);
1368	if (err) {
1369	ext4_std_error(sb, err);
1370	break;
1371	}
1372
1373	ext4_inode_table_set(sb, bg: gdp, blk: group_data->inode_table);
1374	ext4_free_group_clusters_set(sb, bg: gdp,
1375	count: group_data->free_clusters_count);
1376	ext4_free_inodes_set(sb, bg: gdp, EXT4_INODES_PER_GROUP(sb));
1377	if (ext4_has_group_desc_csum(sb))
1378	ext4_itable_unused_set(sb, bg: gdp,
1379	EXT4_INODES_PER_GROUP(sb));
1380	gdp->bg_flags = cpu_to_le16(*bg_flags);
1381	ext4_group_desc_csum_set(sb, group, gdp);
1382
1383	err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1384	if (unlikely(err)) {
1385	ext4_std_error(sb, err);
1386	break;
1387	}
1388
1389	/*
1390	* We can allocate memory for mb_alloc based on the new group
1391	* descriptor
1392	*/
1393	err = ext4_mb_add_groupinfo(sb, i: group, desc: gdp);
1394	if (err)
1395	break;
1396	}
1397	return err;
1398	}
1399
1400	static void ext4_add_overhead(struct super_block *sb,
1401	const ext4_fsblk_t overhead)
1402	{
1403	struct ext4_sb_info *sbi = EXT4_SB(sb);
1404	struct ext4_super_block *es = sbi->s_es;
1405
1406	sbi->s_overhead += overhead;
1407	es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1408	smp_wmb();
1409	}
1410
1411	/*
1412	* ext4_update_super() updates the super block so that the newly added
1413	* groups can be seen by the filesystem.
1414	*
1415	* @sb: super block
1416	* @flex_gd: new added groups
1417	*/
1418	static void ext4_update_super(struct super_block *sb,
1419	struct ext4_new_flex_group_data *flex_gd)
1420	{
1421	ext4_fsblk_t blocks_count = 0;
1422	ext4_fsblk_t free_blocks = 0;
1423	ext4_fsblk_t reserved_blocks = 0;
1424	struct ext4_new_group_data *group_data = flex_gd->groups;
1425	struct ext4_sb_info *sbi = EXT4_SB(sb);
1426	struct ext4_super_block *es = sbi->s_es;
1427	int i;
1428
1429	BUG_ON(flex_gd->count == 0 || group_data == NULL);
1430	/*
1431	* Make the new blocks and inodes valid next. We do this before
1432	* increasing the group count so that once the group is enabled,
1433	* all of its blocks and inodes are already valid.
1434	*
1435	* We always allocate group-by-group, then block-by-block or
1436	* inode-by-inode within a group, so enabling these
1437	* blocks/inodes before the group is live won't actually let us
1438	* allocate the new space yet.
1439	*/
1440	for (i = 0; i < flex_gd->count; i++) {
1441	blocks_count += group_data[i].blocks_count;
1442	free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1443	}
1444
1445	reserved_blocks = ext4_r_blocks_count(es) * 100;
1446	reserved_blocks = div64_u64(dividend: reserved_blocks, divisor: ext4_blocks_count(es));
1447	reserved_blocks *= blocks_count;
1448	do_div(reserved_blocks, 100);
1449
1450	lock_buffer(bh: sbi->s_sbh);
1451	ext4_blocks_count_set(es, blk: ext4_blocks_count(es) + blocks_count);
1452	ext4_free_blocks_count_set(es, blk: ext4_free_blocks_count(es) + free_blocks);
1453	le32_add_cpu(var: &es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1454	flex_gd->count);
1455	le32_add_cpu(var: &es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1456	flex_gd->count);
1457
1458	ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1459	/*
1460	* We need to protect s_groups_count against other CPUs seeing
1461	* inconsistent state in the superblock.
1462	*
1463	* The precise rules we use are:
1464	*
1465	* * Writers must perform a smp_wmb() after updating all
1466	* dependent data and before modifying the groups count
1467	*
1468	* * Readers must perform an smp_rmb() after reading the groups
1469	* count and before reading any dependent data.
1470	*
1471	* NB. These rules can be relaxed when checking the group count
1472	* while freeing data, as we can only allocate from a block
1473	* group after serialising against the group count, and we can
1474	* only then free after serialising in turn against that
1475	* allocation.
1476	*/
1477	smp_wmb();
1478
1479	/* Update the global fs size fields */
1480	sbi->s_groups_count += flex_gd->count;
1481	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1482	(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1483
1484	/* Update the reserved block counts only once the new group is
1485	* active. */
1486	ext4_r_blocks_count_set(es, blk: ext4_r_blocks_count(es) +
1487	reserved_blocks);
1488
1489	/* Update the free space counts */
1490	percpu_counter_add(fbc: &sbi->s_freeclusters_counter,
1491	EXT4_NUM_B2C(sbi, free_blocks));
1492	percpu_counter_add(fbc: &sbi->s_freeinodes_counter,
1493	EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1494
1495	ext4_debug("free blocks count %llu",
1496	percpu_counter_read(&sbi->s_freeclusters_counter));
1497	if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1498	ext4_group_t flex_group;
1499	struct flex_groups *fg;
1500
1501	flex_group = ext4_flex_group(sbi, block_group: group_data[0].group);
1502	fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1503	atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1504	v: &fg->free_clusters);
1505	atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1506	v: &fg->free_inodes);
1507	}
1508
1509	/*
1510	* Update the fs overhead information.
1511	*
1512	* For bigalloc, if the superblock already has a properly calculated
1513	* overhead, update it with a value based on numbers already computed
1514	* above for the newly allocated capacity.
1515	*/
1516	if (ext4_has_feature_bigalloc(sb) && (sbi->s_overhead != 0))
1517	ext4_add_overhead(sb,
1518	EXT4_NUM_B2C(sbi, blocks_count - free_blocks));
1519	else
1520	ext4_calculate_overhead(sb);
1521	es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1522
1523	ext4_superblock_csum_set(sb);
1524	unlock_buffer(bh: sbi->s_sbh);
1525	if (test_opt(sb, DEBUG))
1526	printk(KERN_DEBUG "EXT4-fs: added group %u:"
1527	"%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1528	blocks_count, free_blocks, reserved_blocks);
1529	}
1530
1531	/* Add a flex group to an fs. Ensure we handle all possible error conditions
1532	* _before_ we start modifying the filesystem, because we cannot abort the
1533	* transaction and not have it write the data to disk.
1534	*/
1535	static int ext4_flex_group_add(struct super_block *sb,
1536	struct inode *resize_inode,
1537	struct ext4_new_flex_group_data *flex_gd)
1538	{
1539	struct ext4_sb_info *sbi = EXT4_SB(sb);
1540	struct ext4_super_block *es = sbi->s_es;
1541	ext4_fsblk_t o_blocks_count;
1542	ext4_grpblk_t last;
1543	ext4_group_t group;
1544	handle_t *handle;
1545	unsigned reserved_gdb;
1546	int err = 0, err2 = 0, credit;
1547
1548	BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1549
1550	reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1551	o_blocks_count = ext4_blocks_count(es);
1552	ext4_get_group_no_and_offset(sb, blocknr: o_blocks_count, blockgrpp: &group, offsetp: &last);
1553	BUG_ON(last);
1554
1555	err = setup_new_flex_group_blocks(sb, flex_gd);
1556	if (err)
1557	goto exit;
1558	/*
1559	* We will always be modifying at least the superblock and GDT
1560	* blocks. If we are adding a group past the last current GDT block,
1561	* we will also modify the inode and the dindirect block. If we
1562	* are adding a group with superblock/GDT backups we will also
1563	* modify each of the reserved GDT dindirect blocks.
1564	*/
1565	credit = 3; /* sb, resize inode, resize inode dindirect */
1566	/* GDT blocks */
1567	credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1568	credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1569	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1570	if (IS_ERR(ptr: handle)) {
1571	err = PTR_ERR(ptr: handle);
1572	goto exit;
1573	}
1574
1575	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1576	err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1577	EXT4_JTR_NONE);
1578	if (err)
1579	goto exit_journal;
1580
1581	group = flex_gd->groups[0].group;
1582	BUG_ON(group != sbi->s_groups_count);
1583	err = ext4_add_new_descs(handle, sb, group,
1584	resize_inode, count: flex_gd->count);
1585	if (err)
1586	goto exit_journal;
1587
1588	err = ext4_setup_new_descs(handle, sb, flex_gd);
1589	if (err)
1590	goto exit_journal;
1591
1592	ext4_update_super(sb, flex_gd);
1593
1594	err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1595
1596	exit_journal:
1597	err2 = ext4_journal_stop(handle);
1598	if (!err)
1599	err = err2;
1600
1601	if (!err) {
1602	int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1603	int gdb_num_end = ((group + flex_gd->count - 1) /
1604	EXT4_DESC_PER_BLOCK(sb));
1605	int meta_bg = ext4_has_feature_meta_bg(sb) &&
1606	gdb_num >= le32_to_cpu(es->s_first_meta_bg);
1607	sector_t padding_blocks = meta_bg ? 0 : sbi->s_sbh->b_blocknr -
1608	ext4_group_first_block_no(sb, group_no: 0);
1609
1610	update_backups(sb, blk_off: ext4_group_first_block_no(sb, group_no: 0),
1611	data: (char *)es, size: sizeof(struct ext4_super_block), meta_bg: 0);
1612	for (; gdb_num <= gdb_num_end; gdb_num++) {
1613	struct buffer_head *gdb_bh;
1614
1615	gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1616	gdb_num);
1617	update_backups(sb, blk_off: gdb_bh->b_blocknr - padding_blocks,
1618	data: gdb_bh->b_data, size: gdb_bh->b_size, meta_bg);
1619	}
1620	}
1621	exit:
1622	return err;
1623	}
1624
1625	static int ext4_setup_next_flex_gd(struct super_block *sb,
1626	struct ext4_new_flex_group_data *flex_gd,
1627	ext4_fsblk_t n_blocks_count)
1628	{
1629	struct ext4_sb_info *sbi = EXT4_SB(sb);
1630	struct ext4_super_block *es = sbi->s_es;
1631	struct ext4_new_group_data *group_data = flex_gd->groups;
1632	ext4_fsblk_t o_blocks_count;
1633	ext4_group_t n_group;
1634	ext4_group_t group;
1635	ext4_group_t last_group;
1636	ext4_grpblk_t last;
1637	ext4_grpblk_t clusters_per_group;
1638	unsigned long i;
1639
1640	clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1641
1642	o_blocks_count = ext4_blocks_count(es);
1643
1644	if (o_blocks_count == n_blocks_count)
1645	return 0;
1646
1647	ext4_get_group_no_and_offset(sb, blocknr: o_blocks_count, blockgrpp: &group, offsetp: &last);
1648	BUG_ON(last);
1649	ext4_get_group_no_and_offset(sb, blocknr: n_blocks_count - 1, blockgrpp: &n_group, offsetp: &last);
1650
1651	last_group = group | (flex_gd->resize_bg - 1);
1652	if (last_group > n_group)
1653	last_group = n_group;
1654
1655	flex_gd->count = last_group - group + 1;
1656
1657	for (i = 0; i < flex_gd->count; i++) {
1658	int overhead;
1659
1660	group_data[i].group = group + i;
1661	group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1662	overhead = ext4_group_overhead_blocks(sb, group: group + i);
1663	group_data[i].mdata_blocks = overhead;
1664	group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1665	if (ext4_has_group_desc_csum(sb)) {
1666	flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1667	EXT4_BG_INODE_UNINIT;
1668	if (!test_opt(sb, INIT_INODE_TABLE))
1669	flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1670	} else
1671	flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1672	}
1673
1674	if (last_group == n_group && ext4_has_group_desc_csum(sb))
1675	/* We need to initialize block bitmap of last group. */
1676	flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1677
1678	if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1679	group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1680	group_data[i - 1].free_clusters_count -= clusters_per_group -
1681	last - 1;
1682	}
1683
1684	return 1;
1685	}
1686
1687	/* Add group descriptor data to an existing or new group descriptor block.
1688	* Ensure we handle all possible error conditions _before_ we start modifying
1689	* the filesystem, because we cannot abort the transaction and not have it
1690	* write the data to disk.
1691	*
1692	* If we are on a GDT block boundary, we need to get the reserved GDT block.
1693	* Otherwise, we may need to add backup GDT blocks for a sparse group.
1694	*
1695	* We only need to hold the superblock lock while we are actually adding
1696	* in the new group's counts to the superblock. Prior to that we have
1697	* not really "added" the group at all. We re-check that we are still
1698	* adding in the last group in case things have changed since verifying.
1699	*/
1700	int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1701	{
1702	struct ext4_new_flex_group_data flex_gd;
1703	struct ext4_sb_info *sbi = EXT4_SB(sb);
1704	struct ext4_super_block *es = sbi->s_es;
1705	int reserved_gdb = ext4_bg_has_super(sb, group: input->group) ?
1706	le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1707	struct inode *inode = NULL;
1708	int gdb_off;
1709	int err;
1710	__u16 bg_flags = 0;
1711
1712	gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1713
1714	if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1715	ext4_warning(sb, "Can't resize non-sparse filesystem further");
1716	return -EPERM;
1717	}
1718
1719	if (ext4_blocks_count(es) + input->blocks_count <
1720	ext4_blocks_count(es)) {
1721	ext4_warning(sb, "blocks_count overflow");
1722	return -EINVAL;
1723	}
1724
1725	if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1726	le32_to_cpu(es->s_inodes_count)) {
1727	ext4_warning(sb, "inodes_count overflow");
1728	return -EINVAL;
1729	}
1730
1731	if (reserved_gdb || gdb_off == 0) {
1732	if (!ext4_has_feature_resize_inode(sb) ||
1733	!le16_to_cpu(es->s_reserved_gdt_blocks)) {
1734	ext4_warning(sb,
1735	"No reserved GDT blocks, can't resize");
1736	return -EPERM;
1737	}
1738	inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1739	if (IS_ERR(ptr: inode)) {
1740	ext4_warning(sb, "Error opening resize inode");
1741	return PTR_ERR(ptr: inode);
1742	}
1743	}
1744
1745
1746	err = verify_group_input(sb, input);
1747	if (err)
1748	goto out;
1749
1750	err = ext4_alloc_flex_bg_array(sb, ngroup: input->group + 1);
1751	if (err)
1752	goto out;
1753
1754	err = ext4_mb_alloc_groupinfo(sb, ngroups: input->group + 1);
1755	if (err)
1756	goto out;
1757
1758	flex_gd.count = 1;
1759	flex_gd.groups = input;
1760	flex_gd.bg_flags = &bg_flags;
1761	err = ext4_flex_group_add(sb, resize_inode: inode, flex_gd: &flex_gd);
1762	out:
1763	iput(inode);
1764	return err;
1765	} /* ext4_group_add */
1766
1767	/*
1768	* extend a group without checking assuming that checking has been done.
1769	*/
1770	static int ext4_group_extend_no_check(struct super_block *sb,
1771	ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1772	{
1773	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1774	handle_t *handle;
1775	int err = 0, err2;
1776
1777	/* We will update the superblock, one block bitmap, and
1778	* one group descriptor via ext4_group_add_blocks().
1779	*/
1780	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1781	if (IS_ERR(ptr: handle)) {
1782	err = PTR_ERR(ptr: handle);
1783	ext4_warning(sb, "error %d on journal start", err);
1784	return err;
1785	}
1786
1787	BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1788	err = ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh,
1789	EXT4_JTR_NONE);
1790	if (err) {
1791	ext4_warning(sb, "error %d on journal write access", err);
1792	goto errout;
1793	}
1794
1795	lock_buffer(bh: EXT4_SB(sb)->s_sbh);
1796	ext4_blocks_count_set(es, blk: o_blocks_count + add);
1797	ext4_free_blocks_count_set(es, blk: ext4_free_blocks_count(es) + add);
1798	ext4_superblock_csum_set(sb);
1799	unlock_buffer(bh: EXT4_SB(sb)->s_sbh);
1800	ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1801	o_blocks_count + add);
1802	/* We add the blocks to the bitmap and set the group need init bit */
1803	err = ext4_group_add_blocks(handle, sb, block: o_blocks_count, count: add);
1804	if (err)
1805	goto errout;
1806	ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
1807	ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1808	o_blocks_count + add);
1809	errout:
1810	err2 = ext4_journal_stop(handle);
1811	if (err2 && !err)
1812	err = err2;
1813
1814	if (!err) {
1815	if (test_opt(sb, DEBUG))
1816	printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1817	"blocks\n", ext4_blocks_count(es));
1818	update_backups(sb, blk_off: ext4_group_first_block_no(sb, group_no: 0),
1819	data: (char *)es, size: sizeof(struct ext4_super_block), meta_bg: 0);
1820	}
1821	return err;
1822	}
1823
1824	/*
1825	* Extend the filesystem to the new number of blocks specified. This entry
1826	* point is only used to extend the current filesystem to the end of the last
1827	* existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
1828	* for emergencies (because it has no dependencies on reserved blocks).
1829	*
1830	* If we _really_ wanted, we could use default values to call ext4_group_add()
1831	* allow the "remount" trick to work for arbitrary resizing, assuming enough
1832	* GDT blocks are reserved to grow to the desired size.
1833	*/
1834	int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1835	ext4_fsblk_t n_blocks_count)
1836	{
1837	ext4_fsblk_t o_blocks_count;
1838	ext4_grpblk_t last;
1839	ext4_grpblk_t add;
1840	struct buffer_head *bh;
1841	ext4_group_t group;
1842
1843	o_blocks_count = ext4_blocks_count(es);
1844
1845	if (test_opt(sb, DEBUG))
1846	ext4_msg(sb, KERN_DEBUG,
1847	"extending last group from %llu to %llu blocks",
1848	o_blocks_count, n_blocks_count);
1849
1850	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1851	return 0;
1852
1853	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1854	ext4_msg(sb, KERN_ERR,
1855	"filesystem too large to resize to %llu blocks safely",
1856	n_blocks_count);
1857	return -EINVAL;
1858	}
1859
1860	if (n_blocks_count < o_blocks_count) {
1861	ext4_warning(sb, "can't shrink FS - resize aborted");
1862	return -EINVAL;
1863	}
1864
1865	/* Handle the remaining blocks in the last group only. */
1866	ext4_get_group_no_and_offset(sb, blocknr: o_blocks_count, blockgrpp: &group, offsetp: &last);
1867
1868	if (last == 0) {
1869	ext4_warning(sb, "need to use ext2online to resize further");
1870	return -EPERM;
1871	}
1872
1873	add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1874
1875	if (o_blocks_count + add < o_blocks_count) {
1876	ext4_warning(sb, "blocks_count overflow");
1877	return -EINVAL;
1878	}
1879
1880	if (o_blocks_count + add > n_blocks_count)
1881	add = n_blocks_count - o_blocks_count;
1882
1883	if (o_blocks_count + add < n_blocks_count)
1884	ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1885	o_blocks_count + add, add);
1886
1887	/* See if the device is actually as big as what was requested */
1888	bh = ext4_sb_bread(sb, block: o_blocks_count + add - 1, op_flags: 0);
1889	if (IS_ERR(ptr: bh)) {
1890	ext4_warning(sb, "can't read last block, resize aborted");
1891	return -ENOSPC;
1892	}
1893	brelse(bh);
1894
1895	return ext4_group_extend_no_check(sb, o_blocks_count, add);
1896	} /* ext4_group_extend */
1897
1898
1899	static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1900	{
1901	return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1902	}
1903
1904	/*
1905	* Release the resize inode and drop the resize_inode feature if there
1906	* are no more reserved gdt blocks, and then convert the file system
1907	* to enable meta_bg
1908	*/
1909	static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1910	{
1911	handle_t *handle;
1912	struct ext4_sb_info *sbi = EXT4_SB(sb);
1913	struct ext4_super_block *es = sbi->s_es;
1914	struct ext4_inode_info *ei = EXT4_I(inode);
1915	ext4_fsblk_t nr;
1916	int i, ret, err = 0;
1917	int credits = 1;
1918
1919	ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1920	if (inode) {
1921	if (es->s_reserved_gdt_blocks) {
1922	ext4_error(sb, "Unexpected non-zero "
1923	"s_reserved_gdt_blocks");
1924	return -EPERM;
1925	}
1926
1927	/* Do a quick sanity check of the resize inode */
1928	if (inode->i_blocks != 1 << (inode->i_blkbits -
1929	(9 - sbi->s_cluster_bits)))
1930	goto invalid_resize_inode;
1931	for (i = 0; i < EXT4_N_BLOCKS; i++) {
1932	if (i == EXT4_DIND_BLOCK) {
1933	if (ei->i_data[i])
1934	continue;
1935	else
1936	goto invalid_resize_inode;
1937	}
1938	if (ei->i_data[i])
1939	goto invalid_resize_inode;
1940	}
1941	credits += 3; /* block bitmap, bg descriptor, resize inode */
1942	}
1943
1944	handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1945	if (IS_ERR(ptr: handle))
1946	return PTR_ERR(ptr: handle);
1947
1948	BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1949	err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
1950	EXT4_JTR_NONE);
1951	if (err)
1952	goto errout;
1953
1954	lock_buffer(bh: sbi->s_sbh);
1955	ext4_clear_feature_resize_inode(sb);
1956	ext4_set_feature_meta_bg(sb);
1957	sbi->s_es->s_first_meta_bg =
1958	cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1959	ext4_superblock_csum_set(sb);
1960	unlock_buffer(bh: sbi->s_sbh);
1961
1962	err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1963	if (err) {
1964	ext4_std_error(sb, err);
1965	goto errout;
1966	}
1967
1968	if (inode) {
1969	nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1970	ext4_free_blocks(handle, inode, NULL, block: nr, count: 1,
1971	EXT4_FREE_BLOCKS_METADATA |
1972	EXT4_FREE_BLOCKS_FORGET);
1973	ei->i_data[EXT4_DIND_BLOCK] = 0;
1974	inode->i_blocks = 0;
1975
1976	err = ext4_mark_inode_dirty(handle, inode);
1977	if (err)
1978	ext4_std_error(sb, err);
1979	}
1980
1981	errout:
1982	ret = ext4_journal_stop(handle);
1983	return err ? err : ret;
1984
1985	invalid_resize_inode:
1986	ext4_error(sb, "corrupted/inconsistent resize inode");
1987	return -EINVAL;
1988	}
1989
1990	/*
1991	* ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1992	*
1993	* @sb: super block of the fs to be resized
1994	* @n_blocks_count: the number of blocks resides in the resized fs
1995	*/
1996	int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1997	{
1998	struct ext4_new_flex_group_data *flex_gd = NULL;
1999	struct ext4_sb_info *sbi = EXT4_SB(sb);
2000	struct ext4_super_block *es = sbi->s_es;
2001	struct buffer_head *bh;
2002	struct inode *resize_inode = NULL;
2003	ext4_grpblk_t add, offset;
2004	unsigned long n_desc_blocks;
2005	unsigned long o_desc_blocks;
2006	ext4_group_t o_group;
2007	ext4_group_t n_group;
2008	ext4_fsblk_t o_blocks_count;
2009	ext4_fsblk_t n_blocks_count_retry = 0;
2010	unsigned long last_update_time = 0;
2011	int err = 0;
2012	int meta_bg;
2013	unsigned int flexbg_size = ext4_flex_bg_size(sbi);
2014
2015	/* See if the device is actually as big as what was requested */
2016	bh = ext4_sb_bread(sb, block: n_blocks_count - 1, op_flags: 0);
2017	if (IS_ERR(ptr: bh)) {
2018	ext4_warning(sb, "can't read last block, resize aborted");
2019	return -ENOSPC;
2020	}
2021	brelse(bh);
2022
2023	/*
2024	* For bigalloc, trim the requested size to the nearest cluster
2025	* boundary to avoid creating an unusable filesystem. We do this
2026	* silently, instead of returning an error, to avoid breaking
2027	* callers that blindly resize the filesystem to the full size of
2028	* the underlying block device.
2029	*/
2030	if (ext4_has_feature_bigalloc(sb))
2031	n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
2032
2033	retry:
2034	o_blocks_count = ext4_blocks_count(es);
2035
2036	ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
2037	"to %llu blocks", o_blocks_count, n_blocks_count);
2038
2039	if (n_blocks_count < o_blocks_count) {
2040	/* On-line shrinking not supported */
2041	ext4_warning(sb, "can't shrink FS - resize aborted");
2042	return -EINVAL;
2043	}
2044
2045	if (n_blocks_count == o_blocks_count)
2046	/* Nothing need to do */
2047	return 0;
2048
2049	n_group = ext4_get_group_number(sb, block: n_blocks_count - 1);
2050	if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
2051	ext4_warning(sb, "resize would cause inodes_count overflow");
2052	return -EINVAL;
2053	}
2054	ext4_get_group_no_and_offset(sb, blocknr: o_blocks_count - 1, blockgrpp: &o_group, offsetp: &offset);
2055
2056	n_desc_blocks = num_desc_blocks(sb, groups: n_group + 1);
2057	o_desc_blocks = num_desc_blocks(sb, groups: sbi->s_groups_count);
2058
2059	meta_bg = ext4_has_feature_meta_bg(sb);
2060
2061	if (ext4_has_feature_resize_inode(sb)) {
2062	if (meta_bg) {
2063	ext4_error(sb, "resize_inode and meta_bg enabled "
2064	"simultaneously");
2065	return -EINVAL;
2066	}
2067	if (n_desc_blocks > o_desc_blocks +
2068	le16_to_cpu(es->s_reserved_gdt_blocks)) {
2069	n_blocks_count_retry = n_blocks_count;
2070	n_desc_blocks = o_desc_blocks +
2071	le16_to_cpu(es->s_reserved_gdt_blocks);
2072	n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2073	n_blocks_count = (ext4_fsblk_t)n_group *
2074	EXT4_BLOCKS_PER_GROUP(sb) +
2075	le32_to_cpu(es->s_first_data_block);
2076	n_group--; /* set to last group number */
2077	}
2078
2079	if (!resize_inode)
2080	resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2081	EXT4_IGET_SPECIAL);
2082	if (IS_ERR(ptr: resize_inode)) {
2083	ext4_warning(sb, "Error opening resize inode");
2084	return PTR_ERR(ptr: resize_inode);
2085	}
2086	}
2087
2088	if ((!resize_inode && !meta_bg && n_desc_blocks > o_desc_blocks) || n_blocks_count == o_blocks_count) {
2089	err = ext4_convert_meta_bg(sb, inode: resize_inode);
2090	if (err)
2091	goto out;
2092	if (resize_inode) {
2093	iput(resize_inode);
2094	resize_inode = NULL;
2095	}
2096	if (n_blocks_count_retry) {
2097	n_blocks_count = n_blocks_count_retry;
2098	n_blocks_count_retry = 0;
2099	goto retry;
2100	}
2101	}
2102
2103	/*
2104	* Make sure the last group has enough space so that it's
2105	* guaranteed to have enough space for all metadata blocks
2106	* that it might need to hold. (We might not need to store
2107	* the inode table blocks in the last block group, but there
2108	* will be cases where this might be needed.)
2109	*/
2110	if ((ext4_group_first_block_no(sb, group_no: n_group) +
2111	ext4_group_overhead_blocks(sb, group: n_group) + 2 +
2112	sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2113	n_blocks_count = ext4_group_first_block_no(sb, group_no: n_group);
2114	n_group--;
2115	n_blocks_count_retry = 0;
2116	if (resize_inode) {
2117	iput(resize_inode);
2118	resize_inode = NULL;
2119	}
2120	goto retry;
2121	}
2122
2123	/* extend the last group */
2124	if (n_group == o_group)
2125	add = n_blocks_count - o_blocks_count;
2126	else
2127	add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2128	if (add > 0) {
2129	err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2130	if (err)
2131	goto out;
2132	}
2133
2134	if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
2135	goto out;
2136
2137	err = ext4_alloc_flex_bg_array(sb, ngroup: n_group + 1);
2138	if (err)
2139	goto out;
2140
2141	err = ext4_mb_alloc_groupinfo(sb, ngroups: n_group + 1);
2142	if (err)
2143	goto out;
2144
2145	flex_gd = alloc_flex_gd(flexbg_size, o_group, n_group);
2146	if (flex_gd == NULL) {
2147	err = -ENOMEM;
2148	goto out;
2149	}
2150
2151	/* Add flex groups. Note that a regular group is a
2152	* flex group with 1 group.
2153	*/
2154	while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count)) {
2155	if (time_is_before_jiffies(last_update_time + HZ * 10)) {
2156	if (last_update_time)
2157	ext4_msg(sb, KERN_INFO,
2158	"resized to %llu blocks",
2159	ext4_blocks_count(es));
2160	last_update_time = jiffies;
2161	}
2162	if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2163	break;
2164	err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2165	if (unlikely(err))
2166	break;
2167	}
2168
2169	if (!err && n_blocks_count_retry) {
2170	n_blocks_count = n_blocks_count_retry;
2171	n_blocks_count_retry = 0;
2172	free_flex_gd(flex_gd);
2173	flex_gd = NULL;
2174	if (resize_inode) {
2175	iput(resize_inode);
2176	resize_inode = NULL;
2177	}
2178	goto retry;
2179	}
2180
2181	out:
2182	if (flex_gd)
2183	free_flex_gd(flex_gd);
2184	if (resize_inode != NULL)
2185	iput(resize_inode);
2186	if (err)
2187	ext4_warning(sb, "error (%d) occurred during "
2188	"file system resize", err);
2189	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2190	ext4_blocks_count(es));
2191	return err;
2192	}
2193