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 #define EXT4FS_DEBUG
14
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17
18 #include "ext4_jbd2.h"
19
20 struct ext4_rcu_ptr {
21 struct rcu_head rcu;
22 void *ptr;
23 };
24
ext4_rcu_ptr_callback(struct rcu_head * head)25 static void ext4_rcu_ptr_callback(struct rcu_head *head)
26 {
27 struct ext4_rcu_ptr *ptr;
28
29 ptr = container_of(head, struct ext4_rcu_ptr, rcu);
30 kvfree(ptr->ptr);
31 kfree(ptr);
32 }
33
ext4_kvfree_array_rcu(void * to_free)34 void ext4_kvfree_array_rcu(void *to_free)
35 {
36 struct ext4_rcu_ptr *ptr = kzalloc(sizeof(*ptr), GFP_KERNEL);
37
38 if (ptr) {
39 ptr->ptr = to_free;
40 call_rcu(&ptr->rcu, ext4_rcu_ptr_callback);
41 return;
42 }
43 synchronize_rcu();
44 kvfree(to_free);
45 }
46
ext4_resize_begin(struct super_block * sb)47 int ext4_resize_begin(struct super_block *sb)
48 {
49 struct ext4_sb_info *sbi = EXT4_SB(sb);
50 int ret = 0;
51
52 if (!capable(CAP_SYS_RESOURCE))
53 return -EPERM;
54
55 /*
56 * If the reserved GDT blocks is non-zero, the resize_inode feature
57 * should always be set.
58 */
59 if (EXT4_SB(sb)->s_es->s_reserved_gdt_blocks &&
60 !ext4_has_feature_resize_inode(sb)) {
61 ext4_error(sb, "resize_inode disabled but reserved GDT blocks non-zero");
62 return -EFSCORRUPTED;
63 }
64
65 /*
66 * If we are not using the primary superblock/GDT copy don't resize,
67 * because the user tools have no way of handling this. Probably a
68 * bad time to do it anyways.
69 */
70 if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
71 le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
72 ext4_warning(sb, "won't resize using backup superblock at %llu",
73 (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);
74 return -EPERM;
75 }
76
77 /*
78 * We are not allowed to do online-resizing on a filesystem mounted
79 * with error, because it can destroy the filesystem easily.
80 */
81 if (EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS) {
82 ext4_warning(sb, "There are errors in the filesystem, "
83 "so online resizing is not allowed");
84 return -EPERM;
85 }
86
87 if (ext4_has_feature_sparse_super2(sb)) {
88 ext4_msg(sb, KERN_ERR, "Online resizing not supported with sparse_super2");
89 return -EOPNOTSUPP;
90 }
91
92 if (test_and_set_bit_lock(EXT4_FLAGS_RESIZING,
93 &EXT4_SB(sb)->s_ext4_flags))
94 ret = -EBUSY;
95
96 return ret;
97 }
98
ext4_resize_end(struct super_block * sb)99 void ext4_resize_end(struct super_block *sb)
100 {
101 clear_bit_unlock(EXT4_FLAGS_RESIZING, &EXT4_SB(sb)->s_ext4_flags);
102 smp_mb__after_atomic();
103 }
104
ext4_meta_bg_first_group(struct super_block * sb,ext4_group_t group)105 static ext4_group_t ext4_meta_bg_first_group(struct super_block *sb,
106 ext4_group_t group) {
107 return (group >> EXT4_DESC_PER_BLOCK_BITS(sb)) <<
108 EXT4_DESC_PER_BLOCK_BITS(sb);
109 }
110
ext4_meta_bg_first_block_no(struct super_block * sb,ext4_group_t group)111 static ext4_fsblk_t ext4_meta_bg_first_block_no(struct super_block *sb,
112 ext4_group_t group) {
113 group = ext4_meta_bg_first_group(sb, group);
114 return ext4_group_first_block_no(sb, group);
115 }
116
ext4_group_overhead_blocks(struct super_block * sb,ext4_group_t group)117 static ext4_grpblk_t ext4_group_overhead_blocks(struct super_block *sb,
118 ext4_group_t group) {
119 ext4_grpblk_t overhead;
120 overhead = ext4_bg_num_gdb(sb, group);
121 if (ext4_bg_has_super(sb, group))
122 overhead += 1 +
123 le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
124 return overhead;
125 }
126
127 #define outside(b, first, last) ((b) < (first) || (b) >= (last))
128 #define inside(b, first, last) ((b) >= (first) && (b) < (last))
129
verify_group_input(struct super_block * sb,struct ext4_new_group_data * input)130 static int verify_group_input(struct super_block *sb,
131 struct ext4_new_group_data *input)
132 {
133 struct ext4_sb_info *sbi = EXT4_SB(sb);
134 struct ext4_super_block *es = sbi->s_es;
135 ext4_fsblk_t start = ext4_blocks_count(es);
136 ext4_fsblk_t end = start + input->blocks_count;
137 ext4_group_t group = input->group;
138 ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
139 unsigned overhead;
140 ext4_fsblk_t metaend;
141 struct buffer_head *bh = NULL;
142 ext4_grpblk_t free_blocks_count, offset;
143 int err = -EINVAL;
144
145 if (group != sbi->s_groups_count) {
146 ext4_warning(sb, "Cannot add at group %u (only %u groups)",
147 input->group, sbi->s_groups_count);
148 return -EINVAL;
149 }
150
151 overhead = ext4_group_overhead_blocks(sb, group);
152 metaend = start + overhead;
153 input->free_clusters_count = free_blocks_count =
154 input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
155
156 if (test_opt(sb, DEBUG))
157 printk(KERN_DEBUG "EXT4-fs: adding %s group %u: %u blocks "
158 "(%d free, %u reserved)\n",
159 ext4_bg_has_super(sb, input->group) ? "normal" :
160 "no-super", input->group, input->blocks_count,
161 free_blocks_count, input->reserved_blocks);
162
163 ext4_get_group_no_and_offset(sb, start, NULL, &offset);
164 if (offset != 0)
165 ext4_warning(sb, "Last group not full");
166 else if (input->reserved_blocks > input->blocks_count / 5)
167 ext4_warning(sb, "Reserved blocks too high (%u)",
168 input->reserved_blocks);
169 else if (free_blocks_count < 0)
170 ext4_warning(sb, "Bad blocks count %u",
171 input->blocks_count);
172 else if (IS_ERR(bh = ext4_sb_bread(sb, end - 1, 0))) {
173 err = PTR_ERR(bh);
174 bh = NULL;
175 ext4_warning(sb, "Cannot read last block (%llu)",
176 end - 1);
177 } else if (outside(input->block_bitmap, start, end))
178 ext4_warning(sb, "Block bitmap not in group (block %llu)",
179 (unsigned long long)input->block_bitmap);
180 else if (outside(input->inode_bitmap, start, end))
181 ext4_warning(sb, "Inode bitmap not in group (block %llu)",
182 (unsigned long long)input->inode_bitmap);
183 else if (outside(input->inode_table, start, end) ||
184 outside(itend - 1, start, end))
185 ext4_warning(sb, "Inode table not in group (blocks %llu-%llu)",
186 (unsigned long long)input->inode_table, itend - 1);
187 else if (input->inode_bitmap == input->block_bitmap)
188 ext4_warning(sb, "Block bitmap same as inode bitmap (%llu)",
189 (unsigned long long)input->block_bitmap);
190 else if (inside(input->block_bitmap, input->inode_table, itend))
191 ext4_warning(sb, "Block bitmap (%llu) in inode table "
192 "(%llu-%llu)",
193 (unsigned long long)input->block_bitmap,
194 (unsigned long long)input->inode_table, itend - 1);
195 else if (inside(input->inode_bitmap, input->inode_table, itend))
196 ext4_warning(sb, "Inode bitmap (%llu) in inode table "
197 "(%llu-%llu)",
198 (unsigned long long)input->inode_bitmap,
199 (unsigned long long)input->inode_table, itend - 1);
200 else if (inside(input->block_bitmap, start, metaend))
201 ext4_warning(sb, "Block bitmap (%llu) in GDT table (%llu-%llu)",
202 (unsigned long long)input->block_bitmap,
203 start, metaend - 1);
204 else if (inside(input->inode_bitmap, start, metaend))
205 ext4_warning(sb, "Inode bitmap (%llu) in GDT table (%llu-%llu)",
206 (unsigned long long)input->inode_bitmap,
207 start, metaend - 1);
208 else if (inside(input->inode_table, start, metaend) ||
209 inside(itend - 1, start, metaend))
210 ext4_warning(sb, "Inode table (%llu-%llu) overlaps GDT table "
211 "(%llu-%llu)",
212 (unsigned long long)input->inode_table,
213 itend - 1, start, metaend - 1);
214 else
215 err = 0;
216 brelse(bh);
217
218 return err;
219 }
220
221 /*
222 * ext4_new_flex_group_data is used by 64bit-resize interface to add a flex
223 * group each time.
224 */
225 struct ext4_new_flex_group_data {
226 struct ext4_new_group_data *groups; /* new_group_data for groups
227 in the flex group */
228 __u16 *bg_flags; /* block group flags of groups
229 in @groups */
230 ext4_group_t count; /* number of groups in @groups
231 */
232 };
233
234 /*
235 * alloc_flex_gd() allocates a ext4_new_flex_group_data with size of
236 * @flexbg_size.
237 *
238 * Returns NULL on failure otherwise address of the allocated structure.
239 */
alloc_flex_gd(unsigned long flexbg_size)240 static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
241 {
242 struct ext4_new_flex_group_data *flex_gd;
243
244 flex_gd = kmalloc(sizeof(*flex_gd), GFP_NOFS);
245 if (flex_gd == NULL)
246 goto out3;
247
248 if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_group_data))
249 goto out2;
250 flex_gd->count = flexbg_size;
251
252 flex_gd->groups = kmalloc_array(flexbg_size,
253 sizeof(struct ext4_new_group_data),
254 GFP_NOFS);
255 if (flex_gd->groups == NULL)
256 goto out2;
257
258 flex_gd->bg_flags = kmalloc_array(flexbg_size, sizeof(__u16),
259 GFP_NOFS);
260 if (flex_gd->bg_flags == NULL)
261 goto out1;
262
263 return flex_gd;
264
265 out1:
266 kfree(flex_gd->groups);
267 out2:
268 kfree(flex_gd);
269 out3:
270 return NULL;
271 }
272
free_flex_gd(struct ext4_new_flex_group_data * flex_gd)273 static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
274 {
275 kfree(flex_gd->bg_flags);
276 kfree(flex_gd->groups);
277 kfree(flex_gd);
278 }
279
280 /*
281 * ext4_alloc_group_tables() allocates block bitmaps, inode bitmaps
282 * and inode tables for a flex group.
283 *
284 * This function is used by 64bit-resize. Note that this function allocates
285 * group tables from the 1st group of groups contained by @flexgd, which may
286 * be a partial of a flex group.
287 *
288 * @sb: super block of fs to which the groups belongs
289 *
290 * Returns 0 on a successful allocation of the metadata blocks in the
291 * block group.
292 */
ext4_alloc_group_tables(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd,int flexbg_size)293 static int ext4_alloc_group_tables(struct super_block *sb,
294 struct ext4_new_flex_group_data *flex_gd,
295 int flexbg_size)
296 {
297 struct ext4_new_group_data *group_data = flex_gd->groups;
298 ext4_fsblk_t start_blk;
299 ext4_fsblk_t last_blk;
300 ext4_group_t src_group;
301 ext4_group_t bb_index = 0;
302 ext4_group_t ib_index = 0;
303 ext4_group_t it_index = 0;
304 ext4_group_t group;
305 ext4_group_t last_group;
306 unsigned overhead;
307 __u16 uninit_mask = (flexbg_size > 1) ? ~EXT4_BG_BLOCK_UNINIT : ~0;
308 int i;
309
310 BUG_ON(flex_gd->count == 0 || group_data == NULL);
311
312 src_group = group_data[0].group;
313 last_group = src_group + flex_gd->count - 1;
314
315 BUG_ON((flexbg_size > 1) && ((src_group & ~(flexbg_size - 1)) !=
316 (last_group & ~(flexbg_size - 1))));
317 next_group:
318 group = group_data[0].group;
319 if (src_group >= group_data[0].group + flex_gd->count)
320 return -ENOSPC;
321 start_blk = ext4_group_first_block_no(sb, src_group);
322 last_blk = start_blk + group_data[src_group - group].blocks_count;
323
324 overhead = ext4_group_overhead_blocks(sb, src_group);
325
326 start_blk += overhead;
327
328 /* We collect contiguous blocks as much as possible. */
329 src_group++;
330 for (; src_group <= last_group; src_group++) {
331 overhead = ext4_group_overhead_blocks(sb, src_group);
332 if (overhead == 0)
333 last_blk += group_data[src_group - group].blocks_count;
334 else
335 break;
336 }
337
338 /* Allocate block bitmaps */
339 for (; bb_index < flex_gd->count; bb_index++) {
340 if (start_blk >= last_blk)
341 goto next_group;
342 group_data[bb_index].block_bitmap = start_blk++;
343 group = ext4_get_group_number(sb, start_blk - 1);
344 group -= group_data[0].group;
345 group_data[group].mdata_blocks++;
346 flex_gd->bg_flags[group] &= uninit_mask;
347 }
348
349 /* Allocate inode bitmaps */
350 for (; ib_index < flex_gd->count; ib_index++) {
351 if (start_blk >= last_blk)
352 goto next_group;
353 group_data[ib_index].inode_bitmap = start_blk++;
354 group = ext4_get_group_number(sb, start_blk - 1);
355 group -= group_data[0].group;
356 group_data[group].mdata_blocks++;
357 flex_gd->bg_flags[group] &= uninit_mask;
358 }
359
360 /* Allocate inode tables */
361 for (; it_index < flex_gd->count; it_index++) {
362 unsigned int itb = EXT4_SB(sb)->s_itb_per_group;
363 ext4_fsblk_t next_group_start;
364
365 if (start_blk + itb > last_blk)
366 goto next_group;
367 group_data[it_index].inode_table = start_blk;
368 group = ext4_get_group_number(sb, start_blk);
369 next_group_start = ext4_group_first_block_no(sb, group + 1);
370 group -= group_data[0].group;
371
372 if (start_blk + itb > next_group_start) {
373 flex_gd->bg_flags[group + 1] &= uninit_mask;
374 overhead = start_blk + itb - next_group_start;
375 group_data[group + 1].mdata_blocks += overhead;
376 itb -= overhead;
377 }
378
379 group_data[group].mdata_blocks += itb;
380 flex_gd->bg_flags[group] &= uninit_mask;
381 start_blk += EXT4_SB(sb)->s_itb_per_group;
382 }
383
384 /* Update free clusters count to exclude metadata blocks */
385 for (i = 0; i < flex_gd->count; i++) {
386 group_data[i].free_clusters_count -=
387 EXT4_NUM_B2C(EXT4_SB(sb),
388 group_data[i].mdata_blocks);
389 }
390
391 if (test_opt(sb, DEBUG)) {
392 int i;
393 group = group_data[0].group;
394
395 printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
396 "%d groups, flexbg size is %d:\n", flex_gd->count,
397 flexbg_size);
398
399 for (i = 0; i < flex_gd->count; i++) {
400 ext4_debug(
401 "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
402 ext4_bg_has_super(sb, group + i) ? "normal" :
403 "no-super", group + i,
404 group_data[i].blocks_count,
405 group_data[i].free_clusters_count,
406 group_data[i].mdata_blocks);
407 }
408 }
409 return 0;
410 }
411
bclean(handle_t * handle,struct super_block * sb,ext4_fsblk_t blk)412 static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
413 ext4_fsblk_t blk)
414 {
415 struct buffer_head *bh;
416 int err;
417
418 bh = sb_getblk(sb, blk);
419 if (unlikely(!bh))
420 return ERR_PTR(-ENOMEM);
421 BUFFER_TRACE(bh, "get_write_access");
422 if ((err = ext4_journal_get_write_access(handle, bh))) {
423 brelse(bh);
424 bh = ERR_PTR(err);
425 } else {
426 memset(bh->b_data, 0, sb->s_blocksize);
427 set_buffer_uptodate(bh);
428 }
429
430 return bh;
431 }
432
ext4_resize_ensure_credits_batch(handle_t * handle,int credits)433 static int ext4_resize_ensure_credits_batch(handle_t *handle, int credits)
434 {
435 return ext4_journal_ensure_credits_fn(handle, credits,
436 EXT4_MAX_TRANS_DATA, 0, 0);
437 }
438
439 /*
440 * set_flexbg_block_bitmap() mark clusters [@first_cluster, @last_cluster] used.
441 *
442 * Helper function for ext4_setup_new_group_blocks() which set .
443 *
444 * @sb: super block
445 * @handle: journal handle
446 * @flex_gd: flex group data
447 */
set_flexbg_block_bitmap(struct super_block * sb,handle_t * handle,struct ext4_new_flex_group_data * flex_gd,ext4_fsblk_t first_cluster,ext4_fsblk_t last_cluster)448 static int set_flexbg_block_bitmap(struct super_block *sb, handle_t *handle,
449 struct ext4_new_flex_group_data *flex_gd,
450 ext4_fsblk_t first_cluster, ext4_fsblk_t last_cluster)
451 {
452 struct ext4_sb_info *sbi = EXT4_SB(sb);
453 ext4_group_t count = last_cluster - first_cluster + 1;
454 ext4_group_t count2;
455
456 ext4_debug("mark clusters [%llu-%llu] used\n", first_cluster,
457 last_cluster);
458 for (count2 = count; count > 0;
459 count -= count2, first_cluster += count2) {
460 ext4_fsblk_t start;
461 struct buffer_head *bh;
462 ext4_group_t group;
463 int err;
464
465 group = ext4_get_group_number(sb, EXT4_C2B(sbi, first_cluster));
466 start = EXT4_B2C(sbi, ext4_group_first_block_no(sb, group));
467 group -= flex_gd->groups[0].group;
468
469 count2 = EXT4_CLUSTERS_PER_GROUP(sb) - (first_cluster - start);
470 if (count2 > count)
471 count2 = count;
472
473 if (flex_gd->bg_flags[group] & EXT4_BG_BLOCK_UNINIT) {
474 BUG_ON(flex_gd->count > 1);
475 continue;
476 }
477
478 err = ext4_resize_ensure_credits_batch(handle, 1);
479 if (err < 0)
480 return err;
481
482 bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
483 if (unlikely(!bh))
484 return -ENOMEM;
485
486 BUFFER_TRACE(bh, "get_write_access");
487 err = ext4_journal_get_write_access(handle, bh);
488 if (err) {
489 brelse(bh);
490 return err;
491 }
492 ext4_debug("mark block bitmap %#04llx (+%llu/%u)\n",
493 first_cluster, first_cluster - start, count2);
494 ext4_set_bits(bh->b_data, first_cluster - start, count2);
495
496 err = ext4_handle_dirty_metadata(handle, NULL, bh);
497 brelse(bh);
498 if (unlikely(err))
499 return err;
500 }
501
502 return 0;
503 }
504
505 /*
506 * Set up the block and inode bitmaps, and the inode table for the new groups.
507 * This doesn't need to be part of the main transaction, since we are only
508 * changing blocks outside the actual filesystem. We still do journaling to
509 * ensure the recovery is correct in case of a failure just after resize.
510 * If any part of this fails, we simply abort the resize.
511 *
512 * setup_new_flex_group_blocks handles a flex group as follow:
513 * 1. copy super block and GDT, and initialize group tables if necessary.
514 * In this step, we only set bits in blocks bitmaps for blocks taken by
515 * super block and GDT.
516 * 2. allocate group tables in block bitmaps, that is, set bits in block
517 * bitmap for blocks taken by group tables.
518 */
setup_new_flex_group_blocks(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd)519 static int setup_new_flex_group_blocks(struct super_block *sb,
520 struct ext4_new_flex_group_data *flex_gd)
521 {
522 int group_table_count[] = {1, 1, EXT4_SB(sb)->s_itb_per_group};
523 ext4_fsblk_t start;
524 ext4_fsblk_t block;
525 struct ext4_sb_info *sbi = EXT4_SB(sb);
526 struct ext4_super_block *es = sbi->s_es;
527 struct ext4_new_group_data *group_data = flex_gd->groups;
528 __u16 *bg_flags = flex_gd->bg_flags;
529 handle_t *handle;
530 ext4_group_t group, count;
531 struct buffer_head *bh = NULL;
532 int reserved_gdb, i, j, err = 0, err2;
533 int meta_bg;
534
535 BUG_ON(!flex_gd->count || !group_data ||
536 group_data[0].group != sbi->s_groups_count);
537
538 reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
539 meta_bg = ext4_has_feature_meta_bg(sb);
540
541 /* This transaction may be extended/restarted along the way */
542 handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
543 if (IS_ERR(handle))
544 return PTR_ERR(handle);
545
546 group = group_data[0].group;
547 for (i = 0; i < flex_gd->count; i++, group++) {
548 unsigned long gdblocks;
549 ext4_grpblk_t overhead;
550
551 gdblocks = ext4_bg_num_gdb(sb, group);
552 start = ext4_group_first_block_no(sb, group);
553
554 if (meta_bg == 0 && !ext4_bg_has_super(sb, group))
555 goto handle_itb;
556
557 if (meta_bg == 1) {
558 ext4_group_t first_group;
559 first_group = ext4_meta_bg_first_group(sb, group);
560 if (first_group != group + 1 &&
561 first_group != group + EXT4_DESC_PER_BLOCK(sb) - 1)
562 goto handle_itb;
563 }
564
565 block = start + ext4_bg_has_super(sb, group);
566 /* Copy all of the GDT blocks into the backup in this group */
567 for (j = 0; j < gdblocks; j++, block++) {
568 struct buffer_head *gdb;
569
570 ext4_debug("update backup group %#04llx\n", block);
571 err = ext4_resize_ensure_credits_batch(handle, 1);
572 if (err < 0)
573 goto out;
574
575 gdb = sb_getblk(sb, block);
576 if (unlikely(!gdb)) {
577 err = -ENOMEM;
578 goto out;
579 }
580
581 BUFFER_TRACE(gdb, "get_write_access");
582 err = ext4_journal_get_write_access(handle, gdb);
583 if (err) {
584 brelse(gdb);
585 goto out;
586 }
587 memcpy(gdb->b_data, sbi_array_rcu_deref(sbi,
588 s_group_desc, j)->b_data, gdb->b_size);
589 set_buffer_uptodate(gdb);
590
591 err = ext4_handle_dirty_metadata(handle, NULL, gdb);
592 if (unlikely(err)) {
593 brelse(gdb);
594 goto out;
595 }
596 brelse(gdb);
597 }
598
599 /* Zero out all of the reserved backup group descriptor
600 * table blocks
601 */
602 if (ext4_bg_has_super(sb, group)) {
603 err = sb_issue_zeroout(sb, gdblocks + start + 1,
604 reserved_gdb, GFP_NOFS);
605 if (err)
606 goto out;
607 }
608
609 handle_itb:
610 /* Initialize group tables of the grop @group */
611 if (!(bg_flags[i] & EXT4_BG_INODE_ZEROED))
612 goto handle_bb;
613
614 /* Zero out all of the inode table blocks */
615 block = group_data[i].inode_table;
616 ext4_debug("clear inode table blocks %#04llx -> %#04lx\n",
617 block, sbi->s_itb_per_group);
618 err = sb_issue_zeroout(sb, block, sbi->s_itb_per_group,
619 GFP_NOFS);
620 if (err)
621 goto out;
622
623 handle_bb:
624 if (bg_flags[i] & EXT4_BG_BLOCK_UNINIT)
625 goto handle_ib;
626
627 /* Initialize block bitmap of the @group */
628 block = group_data[i].block_bitmap;
629 err = ext4_resize_ensure_credits_batch(handle, 1);
630 if (err < 0)
631 goto out;
632
633 bh = bclean(handle, sb, block);
634 if (IS_ERR(bh)) {
635 err = PTR_ERR(bh);
636 goto out;
637 }
638 overhead = ext4_group_overhead_blocks(sb, group);
639 if (overhead != 0) {
640 ext4_debug("mark backup superblock %#04llx (+0)\n",
641 start);
642 ext4_set_bits(bh->b_data, 0,
643 EXT4_NUM_B2C(sbi, overhead));
644 }
645 ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
646 sb->s_blocksize * 8, bh->b_data);
647 err = ext4_handle_dirty_metadata(handle, NULL, bh);
648 brelse(bh);
649 if (err)
650 goto out;
651
652 handle_ib:
653 if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
654 continue;
655
656 /* Initialize inode bitmap of the @group */
657 block = group_data[i].inode_bitmap;
658 err = ext4_resize_ensure_credits_batch(handle, 1);
659 if (err < 0)
660 goto out;
661 /* Mark unused entries in inode bitmap used */
662 bh = bclean(handle, sb, block);
663 if (IS_ERR(bh)) {
664 err = PTR_ERR(bh);
665 goto out;
666 }
667
668 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
669 sb->s_blocksize * 8, bh->b_data);
670 err = ext4_handle_dirty_metadata(handle, NULL, bh);
671 brelse(bh);
672 if (err)
673 goto out;
674 }
675
676 /* Mark group tables in block bitmap */
677 for (j = 0; j < GROUP_TABLE_COUNT; j++) {
678 count = group_table_count[j];
679 start = (&group_data[0].block_bitmap)[j];
680 block = start;
681 for (i = 1; i < flex_gd->count; i++) {
682 block += group_table_count[j];
683 if (block == (&group_data[i].block_bitmap)[j]) {
684 count += group_table_count[j];
685 continue;
686 }
687 err = set_flexbg_block_bitmap(sb, handle,
688 flex_gd,
689 EXT4_B2C(sbi, start),
690 EXT4_B2C(sbi,
691 start + count
692 - 1));
693 if (err)
694 goto out;
695 count = group_table_count[j];
696 start = (&group_data[i].block_bitmap)[j];
697 block = start;
698 }
699
700 if (count) {
701 err = set_flexbg_block_bitmap(sb, handle,
702 flex_gd,
703 EXT4_B2C(sbi, start),
704 EXT4_B2C(sbi,
705 start + count
706 - 1));
707 if (err)
708 goto out;
709 }
710 }
711
712 out:
713 err2 = ext4_journal_stop(handle);
714 if (err2 && !err)
715 err = err2;
716
717 return err;
718 }
719
720 /*
721 * Iterate through the groups which hold BACKUP superblock/GDT copies in an
722 * ext4 filesystem. The counters should be initialized to 1, 5, and 7 before
723 * calling this for the first time. In a sparse filesystem it will be the
724 * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
725 * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
726 */
ext4_list_backups(struct super_block * sb,unsigned * three,unsigned * five,unsigned * seven)727 static unsigned ext4_list_backups(struct super_block *sb, unsigned *three,
728 unsigned *five, unsigned *seven)
729 {
730 unsigned *min = three;
731 int mult = 3;
732 unsigned ret;
733
734 if (!ext4_has_feature_sparse_super(sb)) {
735 ret = *min;
736 *min += 1;
737 return ret;
738 }
739
740 if (*five < *min) {
741 min = five;
742 mult = 5;
743 }
744 if (*seven < *min) {
745 min = seven;
746 mult = 7;
747 }
748
749 ret = *min;
750 *min *= mult;
751
752 return ret;
753 }
754
755 /*
756 * Check that all of the backup GDT blocks are held in the primary GDT block.
757 * It is assumed that they are stored in group order. Returns the number of
758 * groups in current filesystem that have BACKUPS, or -ve error code.
759 */
verify_reserved_gdb(struct super_block * sb,ext4_group_t end,struct buffer_head * primary)760 static int verify_reserved_gdb(struct super_block *sb,
761 ext4_group_t end,
762 struct buffer_head *primary)
763 {
764 const ext4_fsblk_t blk = primary->b_blocknr;
765 unsigned three = 1;
766 unsigned five = 5;
767 unsigned seven = 7;
768 unsigned grp;
769 __le32 *p = (__le32 *)primary->b_data;
770 int gdbackups = 0;
771
772 while ((grp = ext4_list_backups(sb, &three, &five, &seven)) < end) {
773 if (le32_to_cpu(*p++) !=
774 grp * EXT4_BLOCKS_PER_GROUP(sb) + blk){
775 ext4_warning(sb, "reserved GDT %llu"
776 " missing grp %d (%llu)",
777 blk, grp,
778 grp *
779 (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
780 blk);
781 return -EINVAL;
782 }
783 if (++gdbackups > EXT4_ADDR_PER_BLOCK(sb))
784 return -EFBIG;
785 }
786
787 return gdbackups;
788 }
789
790 /*
791 * Called when we need to bring a reserved group descriptor table block into
792 * use from the resize inode. The primary copy of the new GDT block currently
793 * is an indirect block (under the double indirect block in the resize inode).
794 * The new backup GDT blocks will be stored as leaf blocks in this indirect
795 * block, in group order. Even though we know all the block numbers we need,
796 * we check to ensure that the resize inode has actually reserved these blocks.
797 *
798 * Don't need to update the block bitmaps because the blocks are still in use.
799 *
800 * We get all of the error cases out of the way, so that we are sure to not
801 * fail once we start modifying the data on disk, because JBD has no rollback.
802 */
add_new_gdb(handle_t * handle,struct inode * inode,ext4_group_t group)803 static int add_new_gdb(handle_t *handle, struct inode *inode,
804 ext4_group_t group)
805 {
806 struct super_block *sb = inode->i_sb;
807 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
808 unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
809 ext4_fsblk_t gdblock = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
810 struct buffer_head **o_group_desc, **n_group_desc = NULL;
811 struct buffer_head *dind = NULL;
812 struct buffer_head *gdb_bh = NULL;
813 int gdbackups;
814 struct ext4_iloc iloc = { .bh = NULL };
815 __le32 *data;
816 int err;
817
818 if (test_opt(sb, DEBUG))
819 printk(KERN_DEBUG
820 "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
821 gdb_num);
822
823 gdb_bh = ext4_sb_bread(sb, gdblock, 0);
824 if (IS_ERR(gdb_bh))
825 return PTR_ERR(gdb_bh);
826
827 gdbackups = verify_reserved_gdb(sb, group, gdb_bh);
828 if (gdbackups < 0) {
829 err = gdbackups;
830 goto errout;
831 }
832
833 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
834 dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
835 if (IS_ERR(dind)) {
836 err = PTR_ERR(dind);
837 dind = NULL;
838 goto errout;
839 }
840
841 data = (__le32 *)dind->b_data;
842 if (le32_to_cpu(data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)]) != gdblock) {
843 ext4_warning(sb, "new group %u GDT block %llu not reserved",
844 group, gdblock);
845 err = -EINVAL;
846 goto errout;
847 }
848
849 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
850 err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
851 if (unlikely(err))
852 goto errout;
853
854 BUFFER_TRACE(gdb_bh, "get_write_access");
855 err = ext4_journal_get_write_access(handle, gdb_bh);
856 if (unlikely(err))
857 goto errout;
858
859 BUFFER_TRACE(dind, "get_write_access");
860 err = ext4_journal_get_write_access(handle, dind);
861 if (unlikely(err)) {
862 ext4_std_error(sb, err);
863 goto errout;
864 }
865
866 /* ext4_reserve_inode_write() gets a reference on the iloc */
867 err = ext4_reserve_inode_write(handle, inode, &iloc);
868 if (unlikely(err))
869 goto errout;
870
871 n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
872 GFP_KERNEL);
873 if (!n_group_desc) {
874 err = -ENOMEM;
875 ext4_warning(sb, "not enough memory for %lu groups",
876 gdb_num + 1);
877 goto errout;
878 }
879
880 /*
881 * Finally, we have all of the possible failures behind us...
882 *
883 * Remove new GDT block from inode double-indirect block and clear out
884 * the new GDT block for use (which also "frees" the backup GDT blocks
885 * from the reserved inode). We don't need to change the bitmaps for
886 * these blocks, because they are marked as in-use from being in the
887 * reserved inode, and will become GDT blocks (primary and backup).
888 */
889 data[gdb_num % EXT4_ADDR_PER_BLOCK(sb)] = 0;
890 err = ext4_handle_dirty_metadata(handle, NULL, dind);
891 if (unlikely(err)) {
892 ext4_std_error(sb, err);
893 goto errout;
894 }
895 inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >>
896 (9 - EXT4_SB(sb)->s_cluster_bits);
897 ext4_mark_iloc_dirty(handle, inode, &iloc);
898 memset(gdb_bh->b_data, 0, sb->s_blocksize);
899 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
900 if (unlikely(err)) {
901 ext4_std_error(sb, err);
902 iloc.bh = NULL;
903 goto errout;
904 }
905 brelse(dind);
906
907 rcu_read_lock();
908 o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
909 memcpy(n_group_desc, o_group_desc,
910 EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
911 rcu_read_unlock();
912 n_group_desc[gdb_num] = gdb_bh;
913 rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
914 EXT4_SB(sb)->s_gdb_count++;
915 ext4_kvfree_array_rcu(o_group_desc);
916
917 lock_buffer(EXT4_SB(sb)->s_sbh);
918 le16_add_cpu(&es->s_reserved_gdt_blocks, -1);
919 ext4_superblock_csum_set(sb);
920 unlock_buffer(EXT4_SB(sb)->s_sbh);
921 err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
922 if (err)
923 ext4_std_error(sb, err);
924 return err;
925 errout:
926 kvfree(n_group_desc);
927 brelse(iloc.bh);
928 brelse(dind);
929 brelse(gdb_bh);
930
931 ext4_debug("leaving with error %d\n", err);
932 return err;
933 }
934
935 /*
936 * add_new_gdb_meta_bg is the sister of add_new_gdb.
937 */
add_new_gdb_meta_bg(struct super_block * sb,handle_t * handle,ext4_group_t group)938 static int add_new_gdb_meta_bg(struct super_block *sb,
939 handle_t *handle, ext4_group_t group) {
940 ext4_fsblk_t gdblock;
941 struct buffer_head *gdb_bh;
942 struct buffer_head **o_group_desc, **n_group_desc;
943 unsigned long gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
944 int err;
945
946 gdblock = ext4_meta_bg_first_block_no(sb, group) +
947 ext4_bg_has_super(sb, group);
948 gdb_bh = ext4_sb_bread(sb, gdblock, 0);
949 if (IS_ERR(gdb_bh))
950 return PTR_ERR(gdb_bh);
951 n_group_desc = kvmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
952 GFP_KERNEL);
953 if (!n_group_desc) {
954 brelse(gdb_bh);
955 err = -ENOMEM;
956 ext4_warning(sb, "not enough memory for %lu groups",
957 gdb_num + 1);
958 return err;
959 }
960
961 rcu_read_lock();
962 o_group_desc = rcu_dereference(EXT4_SB(sb)->s_group_desc);
963 memcpy(n_group_desc, o_group_desc,
964 EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
965 rcu_read_unlock();
966 n_group_desc[gdb_num] = gdb_bh;
967
968 BUFFER_TRACE(gdb_bh, "get_write_access");
969 err = ext4_journal_get_write_access(handle, gdb_bh);
970 if (err) {
971 kvfree(n_group_desc);
972 brelse(gdb_bh);
973 return err;
974 }
975
976 rcu_assign_pointer(EXT4_SB(sb)->s_group_desc, n_group_desc);
977 EXT4_SB(sb)->s_gdb_count++;
978 ext4_kvfree_array_rcu(o_group_desc);
979 return err;
980 }
981
982 /*
983 * Called when we are adding a new group which has a backup copy of each of
984 * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
985 * We need to add these reserved backup GDT blocks to the resize inode, so
986 * that they are kept for future resizing and not allocated to files.
987 *
988 * Each reserved backup GDT block will go into a different indirect block.
989 * The indirect blocks are actually the primary reserved GDT blocks,
990 * so we know in advance what their block numbers are. We only get the
991 * double-indirect block to verify it is pointing to the primary reserved
992 * GDT blocks so we don't overwrite a data block by accident. The reserved
993 * backup GDT blocks are stored in their reserved primary GDT block.
994 */
reserve_backup_gdb(handle_t * handle,struct inode * inode,ext4_group_t group)995 static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
996 ext4_group_t group)
997 {
998 struct super_block *sb = inode->i_sb;
999 int reserved_gdb =le16_to_cpu(EXT4_SB(sb)->s_es->s_reserved_gdt_blocks);
1000 int cluster_bits = EXT4_SB(sb)->s_cluster_bits;
1001 struct buffer_head **primary;
1002 struct buffer_head *dind;
1003 struct ext4_iloc iloc;
1004 ext4_fsblk_t blk;
1005 __le32 *data, *end;
1006 int gdbackups = 0;
1007 int res, i;
1008 int err;
1009
1010 primary = kmalloc_array(reserved_gdb, sizeof(*primary), GFP_NOFS);
1011 if (!primary)
1012 return -ENOMEM;
1013
1014 data = EXT4_I(inode)->i_data + EXT4_DIND_BLOCK;
1015 dind = ext4_sb_bread(sb, le32_to_cpu(*data), 0);
1016 if (IS_ERR(dind)) {
1017 err = PTR_ERR(dind);
1018 dind = NULL;
1019 goto exit_free;
1020 }
1021
1022 blk = EXT4_SB(sb)->s_sbh->b_blocknr + 1 + EXT4_SB(sb)->s_gdb_count;
1023 data = (__le32 *)dind->b_data + (EXT4_SB(sb)->s_gdb_count %
1024 EXT4_ADDR_PER_BLOCK(sb));
1025 end = (__le32 *)dind->b_data + EXT4_ADDR_PER_BLOCK(sb);
1026
1027 /* Get each reserved primary GDT block and verify it holds backups */
1028 for (res = 0; res < reserved_gdb; res++, blk++) {
1029 if (le32_to_cpu(*data) != blk) {
1030 ext4_warning(sb, "reserved block %llu"
1031 " not at offset %ld",
1032 blk,
1033 (long)(data - (__le32 *)dind->b_data));
1034 err = -EINVAL;
1035 goto exit_bh;
1036 }
1037 primary[res] = ext4_sb_bread(sb, blk, 0);
1038 if (IS_ERR(primary[res])) {
1039 err = PTR_ERR(primary[res]);
1040 primary[res] = NULL;
1041 goto exit_bh;
1042 }
1043 gdbackups = verify_reserved_gdb(sb, group, primary[res]);
1044 if (gdbackups < 0) {
1045 brelse(primary[res]);
1046 err = gdbackups;
1047 goto exit_bh;
1048 }
1049 if (++data >= end)
1050 data = (__le32 *)dind->b_data;
1051 }
1052
1053 for (i = 0; i < reserved_gdb; i++) {
1054 BUFFER_TRACE(primary[i], "get_write_access");
1055 if ((err = ext4_journal_get_write_access(handle, primary[i])))
1056 goto exit_bh;
1057 }
1058
1059 if ((err = ext4_reserve_inode_write(handle, inode, &iloc)))
1060 goto exit_bh;
1061
1062 /*
1063 * Finally we can add each of the reserved backup GDT blocks from
1064 * the new group to its reserved primary GDT block.
1065 */
1066 blk = group * EXT4_BLOCKS_PER_GROUP(sb);
1067 for (i = 0; i < reserved_gdb; i++) {
1068 int err2;
1069 data = (__le32 *)primary[i]->b_data;
1070 /* printk("reserving backup %lu[%u] = %lu\n",
1071 primary[i]->b_blocknr, gdbackups,
1072 blk + primary[i]->b_blocknr); */
1073 data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
1074 err2 = ext4_handle_dirty_metadata(handle, NULL, primary[i]);
1075 if (!err)
1076 err = err2;
1077 }
1078
1079 inode->i_blocks += reserved_gdb * sb->s_blocksize >> (9 - cluster_bits);
1080 ext4_mark_iloc_dirty(handle, inode, &iloc);
1081
1082 exit_bh:
1083 while (--res >= 0)
1084 brelse(primary[res]);
1085 brelse(dind);
1086
1087 exit_free:
1088 kfree(primary);
1089
1090 return err;
1091 }
1092
1093 /*
1094 * Update the backup copies of the ext4 metadata. These don't need to be part
1095 * of the main resize transaction, because e2fsck will re-write them if there
1096 * is a problem (basically only OOM will cause a problem). However, we
1097 * _should_ update the backups if possible, in case the primary gets trashed
1098 * for some reason and we need to run e2fsck from a backup superblock. The
1099 * important part is that the new block and inode counts are in the backup
1100 * superblocks, and the location of the new group metadata in the GDT backups.
1101 *
1102 * We do not need take the s_resize_lock for this, because these
1103 * blocks are not otherwise touched by the filesystem code when it is
1104 * mounted. We don't need to worry about last changing from
1105 * sbi->s_groups_count, because the worst that can happen is that we
1106 * do not copy the full number of backups at this time. The resize
1107 * which changed s_groups_count will backup again.
1108 */
update_backups(struct super_block * sb,sector_t blk_off,char * data,int size,int meta_bg)1109 static void update_backups(struct super_block *sb, sector_t blk_off, char *data,
1110 int size, int meta_bg)
1111 {
1112 struct ext4_sb_info *sbi = EXT4_SB(sb);
1113 ext4_group_t last;
1114 const int bpg = EXT4_BLOCKS_PER_GROUP(sb);
1115 unsigned three = 1;
1116 unsigned five = 5;
1117 unsigned seven = 7;
1118 ext4_group_t group = 0;
1119 int rest = sb->s_blocksize - size;
1120 handle_t *handle;
1121 int err = 0, err2;
1122
1123 handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, EXT4_MAX_TRANS_DATA);
1124 if (IS_ERR(handle)) {
1125 group = 1;
1126 err = PTR_ERR(handle);
1127 goto exit_err;
1128 }
1129
1130 if (meta_bg == 0) {
1131 group = ext4_list_backups(sb, &three, &five, &seven);
1132 last = sbi->s_groups_count;
1133 } else {
1134 group = ext4_get_group_number(sb, blk_off) + 1;
1135 last = (ext4_group_t)(group + EXT4_DESC_PER_BLOCK(sb) - 2);
1136 }
1137
1138 while (group < sbi->s_groups_count) {
1139 struct buffer_head *bh;
1140 ext4_fsblk_t backup_block;
1141
1142 /* Out of journal space, and can't get more - abort - so sad */
1143 err = ext4_resize_ensure_credits_batch(handle, 1);
1144 if (err < 0)
1145 break;
1146
1147 if (meta_bg == 0)
1148 backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1149 else
1150 backup_block = (ext4_group_first_block_no(sb, group) +
1151 ext4_bg_has_super(sb, group));
1152
1153 bh = sb_getblk(sb, backup_block);
1154 if (unlikely(!bh)) {
1155 err = -ENOMEM;
1156 break;
1157 }
1158 ext4_debug("update metadata backup %llu(+%llu)\n",
1159 backup_block, backup_block -
1160 ext4_group_first_block_no(sb, group));
1161 BUFFER_TRACE(bh, "get_write_access");
1162 if ((err = ext4_journal_get_write_access(handle, bh))) {
1163 brelse(bh);
1164 break;
1165 }
1166 lock_buffer(bh);
1167 memcpy(bh->b_data, data, size);
1168 if (rest)
1169 memset(bh->b_data + size, 0, rest);
1170 set_buffer_uptodate(bh);
1171 unlock_buffer(bh);
1172 err = ext4_handle_dirty_metadata(handle, NULL, bh);
1173 if (unlikely(err))
1174 ext4_std_error(sb, err);
1175 brelse(bh);
1176
1177 if (meta_bg == 0)
1178 group = ext4_list_backups(sb, &three, &five, &seven);
1179 else if (group == last)
1180 break;
1181 else
1182 group = last;
1183 }
1184 if ((err2 = ext4_journal_stop(handle)) && !err)
1185 err = err2;
1186
1187 /*
1188 * Ugh! Need to have e2fsck write the backup copies. It is too
1189 * late to revert the resize, we shouldn't fail just because of
1190 * the backup copies (they are only needed in case of corruption).
1191 *
1192 * However, if we got here we have a journal problem too, so we
1193 * can't really start a transaction to mark the superblock.
1194 * Chicken out and just set the flag on the hope it will be written
1195 * to disk, and if not - we will simply wait until next fsck.
1196 */
1197 exit_err:
1198 if (err) {
1199 ext4_warning(sb, "can't update backup for group %u (err %d), "
1200 "forcing fsck on next reboot", group, err);
1201 sbi->s_mount_state &= ~EXT4_VALID_FS;
1202 sbi->s_es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
1203 mark_buffer_dirty(sbi->s_sbh);
1204 }
1205 }
1206
1207 /*
1208 * ext4_add_new_descs() adds @count group descriptor of groups
1209 * starting at @group
1210 *
1211 * @handle: journal handle
1212 * @sb: super block
1213 * @group: the group no. of the first group desc to be added
1214 * @resize_inode: the resize inode
1215 * @count: number of group descriptors to be added
1216 */
ext4_add_new_descs(handle_t * handle,struct super_block * sb,ext4_group_t group,struct inode * resize_inode,ext4_group_t count)1217 static int ext4_add_new_descs(handle_t *handle, struct super_block *sb,
1218 ext4_group_t group, struct inode *resize_inode,
1219 ext4_group_t count)
1220 {
1221 struct ext4_sb_info *sbi = EXT4_SB(sb);
1222 struct ext4_super_block *es = sbi->s_es;
1223 struct buffer_head *gdb_bh;
1224 int i, gdb_off, gdb_num, err = 0;
1225 int meta_bg;
1226
1227 meta_bg = ext4_has_feature_meta_bg(sb);
1228 for (i = 0; i < count; i++, group++) {
1229 int reserved_gdb = ext4_bg_has_super(sb, group) ?
1230 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1231
1232 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1233 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1234
1235 /*
1236 * We will only either add reserved group blocks to a backup group
1237 * or remove reserved blocks for the first group in a new group block.
1238 * Doing both would be mean more complex code, and sane people don't
1239 * use non-sparse filesystems anymore. This is already checked above.
1240 */
1241 if (gdb_off) {
1242 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1243 gdb_num);
1244 BUFFER_TRACE(gdb_bh, "get_write_access");
1245 err = ext4_journal_get_write_access(handle, gdb_bh);
1246
1247 if (!err && reserved_gdb && ext4_bg_num_gdb(sb, group))
1248 err = reserve_backup_gdb(handle, resize_inode, group);
1249 } else if (meta_bg != 0) {
1250 err = add_new_gdb_meta_bg(sb, handle, group);
1251 } else {
1252 err = add_new_gdb(handle, resize_inode, group);
1253 }
1254 if (err)
1255 break;
1256 }
1257 return err;
1258 }
1259
ext4_get_bitmap(struct super_block * sb,__u64 block)1260 static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
1261 {
1262 struct buffer_head *bh = sb_getblk(sb, block);
1263 if (unlikely(!bh))
1264 return NULL;
1265 if (!bh_uptodate_or_lock(bh)) {
1266 if (ext4_read_bh(bh, 0, NULL) < 0) {
1267 brelse(bh);
1268 return NULL;
1269 }
1270 }
1271
1272 return bh;
1273 }
1274
ext4_set_bitmap_checksums(struct super_block * sb,ext4_group_t group,struct ext4_group_desc * gdp,struct ext4_new_group_data * group_data)1275 static int ext4_set_bitmap_checksums(struct super_block *sb,
1276 ext4_group_t group,
1277 struct ext4_group_desc *gdp,
1278 struct ext4_new_group_data *group_data)
1279 {
1280 struct buffer_head *bh;
1281
1282 if (!ext4_has_metadata_csum(sb))
1283 return 0;
1284
1285 bh = ext4_get_bitmap(sb, group_data->inode_bitmap);
1286 if (!bh)
1287 return -EIO;
1288 ext4_inode_bitmap_csum_set(sb, group, gdp, bh,
1289 EXT4_INODES_PER_GROUP(sb) / 8);
1290 brelse(bh);
1291
1292 bh = ext4_get_bitmap(sb, group_data->block_bitmap);
1293 if (!bh)
1294 return -EIO;
1295 ext4_block_bitmap_csum_set(sb, group, gdp, bh);
1296 brelse(bh);
1297
1298 return 0;
1299 }
1300
1301 /*
1302 * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg
1303 */
ext4_setup_new_descs(handle_t * handle,struct super_block * sb,struct ext4_new_flex_group_data * flex_gd)1304 static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb,
1305 struct ext4_new_flex_group_data *flex_gd)
1306 {
1307 struct ext4_new_group_data *group_data = flex_gd->groups;
1308 struct ext4_group_desc *gdp;
1309 struct ext4_sb_info *sbi = EXT4_SB(sb);
1310 struct buffer_head *gdb_bh;
1311 ext4_group_t group;
1312 __u16 *bg_flags = flex_gd->bg_flags;
1313 int i, gdb_off, gdb_num, err = 0;
1314
1315
1316 for (i = 0; i < flex_gd->count; i++, group_data++, bg_flags++) {
1317 group = group_data->group;
1318
1319 gdb_off = group % EXT4_DESC_PER_BLOCK(sb);
1320 gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1321
1322 /*
1323 * get_write_access() has been called on gdb_bh by ext4_add_new_desc().
1324 */
1325 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc, gdb_num);
1326 /* Update group descriptor block for new group */
1327 gdp = (struct ext4_group_desc *)(gdb_bh->b_data +
1328 gdb_off * EXT4_DESC_SIZE(sb));
1329
1330 memset(gdp, 0, EXT4_DESC_SIZE(sb));
1331 ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap);
1332 ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap);
1333 err = ext4_set_bitmap_checksums(sb, group, gdp, group_data);
1334 if (err) {
1335 ext4_std_error(sb, err);
1336 break;
1337 }
1338
1339 ext4_inode_table_set(sb, gdp, group_data->inode_table);
1340 ext4_free_group_clusters_set(sb, gdp,
1341 group_data->free_clusters_count);
1342 ext4_free_inodes_set(sb, gdp, EXT4_INODES_PER_GROUP(sb));
1343 if (ext4_has_group_desc_csum(sb))
1344 ext4_itable_unused_set(sb, gdp,
1345 EXT4_INODES_PER_GROUP(sb));
1346 gdp->bg_flags = cpu_to_le16(*bg_flags);
1347 ext4_group_desc_csum_set(sb, group, gdp);
1348
1349 err = ext4_handle_dirty_metadata(handle, NULL, gdb_bh);
1350 if (unlikely(err)) {
1351 ext4_std_error(sb, err);
1352 break;
1353 }
1354
1355 /*
1356 * We can allocate memory for mb_alloc based on the new group
1357 * descriptor
1358 */
1359 err = ext4_mb_add_groupinfo(sb, group, gdp);
1360 if (err)
1361 break;
1362 }
1363 return err;
1364 }
1365
1366 /*
1367 * ext4_update_super() updates the super block so that the newly added
1368 * groups can be seen by the filesystem.
1369 *
1370 * @sb: super block
1371 * @flex_gd: new added groups
1372 */
ext4_update_super(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd)1373 static void ext4_update_super(struct super_block *sb,
1374 struct ext4_new_flex_group_data *flex_gd)
1375 {
1376 ext4_fsblk_t blocks_count = 0;
1377 ext4_fsblk_t free_blocks = 0;
1378 ext4_fsblk_t reserved_blocks = 0;
1379 struct ext4_new_group_data *group_data = flex_gd->groups;
1380 struct ext4_sb_info *sbi = EXT4_SB(sb);
1381 struct ext4_super_block *es = sbi->s_es;
1382 int i;
1383
1384 BUG_ON(flex_gd->count == 0 || group_data == NULL);
1385 /*
1386 * Make the new blocks and inodes valid next. We do this before
1387 * increasing the group count so that once the group is enabled,
1388 * all of its blocks and inodes are already valid.
1389 *
1390 * We always allocate group-by-group, then block-by-block or
1391 * inode-by-inode within a group, so enabling these
1392 * blocks/inodes before the group is live won't actually let us
1393 * allocate the new space yet.
1394 */
1395 for (i = 0; i < flex_gd->count; i++) {
1396 blocks_count += group_data[i].blocks_count;
1397 free_blocks += EXT4_C2B(sbi, group_data[i].free_clusters_count);
1398 }
1399
1400 reserved_blocks = ext4_r_blocks_count(es) * 100;
1401 reserved_blocks = div64_u64(reserved_blocks, ext4_blocks_count(es));
1402 reserved_blocks *= blocks_count;
1403 do_div(reserved_blocks, 100);
1404
1405 lock_buffer(sbi->s_sbh);
1406 ext4_blocks_count_set(es, ext4_blocks_count(es) + blocks_count);
1407 ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + free_blocks);
1408 le32_add_cpu(&es->s_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1409 flex_gd->count);
1410 le32_add_cpu(&es->s_free_inodes_count, EXT4_INODES_PER_GROUP(sb) *
1411 flex_gd->count);
1412
1413 ext4_debug("free blocks count %llu", ext4_free_blocks_count(es));
1414 /*
1415 * We need to protect s_groups_count against other CPUs seeing
1416 * inconsistent state in the superblock.
1417 *
1418 * The precise rules we use are:
1419 *
1420 * * Writers must perform a smp_wmb() after updating all
1421 * dependent data and before modifying the groups count
1422 *
1423 * * Readers must perform an smp_rmb() after reading the groups
1424 * count and before reading any dependent data.
1425 *
1426 * NB. These rules can be relaxed when checking the group count
1427 * while freeing data, as we can only allocate from a block
1428 * group after serialising against the group count, and we can
1429 * only then free after serialising in turn against that
1430 * allocation.
1431 */
1432 smp_wmb();
1433
1434 /* Update the global fs size fields */
1435 sbi->s_groups_count += flex_gd->count;
1436 sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
1437 (EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
1438
1439 /* Update the reserved block counts only once the new group is
1440 * active. */
1441 ext4_r_blocks_count_set(es, ext4_r_blocks_count(es) +
1442 reserved_blocks);
1443 ext4_superblock_csum_set(sb);
1444 unlock_buffer(sbi->s_sbh);
1445
1446 /* Update the free space counts */
1447 percpu_counter_add(&sbi->s_freeclusters_counter,
1448 EXT4_NUM_B2C(sbi, free_blocks));
1449 percpu_counter_add(&sbi->s_freeinodes_counter,
1450 EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
1451
1452 ext4_debug("free blocks count %llu",
1453 percpu_counter_read(&sbi->s_freeclusters_counter));
1454 if (ext4_has_feature_flex_bg(sb) && sbi->s_log_groups_per_flex) {
1455 ext4_group_t flex_group;
1456 struct flex_groups *fg;
1457
1458 flex_group = ext4_flex_group(sbi, group_data[0].group);
1459 fg = sbi_array_rcu_deref(sbi, s_flex_groups, flex_group);
1460 atomic64_add(EXT4_NUM_B2C(sbi, free_blocks),
1461 &fg->free_clusters);
1462 atomic_add(EXT4_INODES_PER_GROUP(sb) * flex_gd->count,
1463 &fg->free_inodes);
1464 }
1465
1466 /*
1467 * Update the fs overhead information
1468 */
1469 ext4_calculate_overhead(sb);
1470 es->s_overhead_clusters = cpu_to_le32(sbi->s_overhead);
1471
1472 if (test_opt(sb, DEBUG))
1473 printk(KERN_DEBUG "EXT4-fs: added group %u:"
1474 "%llu blocks(%llu free %llu reserved)\n", flex_gd->count,
1475 blocks_count, free_blocks, reserved_blocks);
1476 }
1477
1478 /* Add a flex group to an fs. Ensure we handle all possible error conditions
1479 * _before_ we start modifying the filesystem, because we cannot abort the
1480 * transaction and not have it write the data to disk.
1481 */
ext4_flex_group_add(struct super_block * sb,struct inode * resize_inode,struct ext4_new_flex_group_data * flex_gd)1482 static int ext4_flex_group_add(struct super_block *sb,
1483 struct inode *resize_inode,
1484 struct ext4_new_flex_group_data *flex_gd)
1485 {
1486 struct ext4_sb_info *sbi = EXT4_SB(sb);
1487 struct ext4_super_block *es = sbi->s_es;
1488 ext4_fsblk_t o_blocks_count;
1489 ext4_grpblk_t last;
1490 ext4_group_t group;
1491 handle_t *handle;
1492 unsigned reserved_gdb;
1493 int err = 0, err2 = 0, credit;
1494
1495 BUG_ON(!flex_gd->count || !flex_gd->groups || !flex_gd->bg_flags);
1496
1497 reserved_gdb = le16_to_cpu(es->s_reserved_gdt_blocks);
1498 o_blocks_count = ext4_blocks_count(es);
1499 ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1500 BUG_ON(last);
1501
1502 err = setup_new_flex_group_blocks(sb, flex_gd);
1503 if (err)
1504 goto exit;
1505 /*
1506 * We will always be modifying at least the superblock and GDT
1507 * blocks. If we are adding a group past the last current GDT block,
1508 * we will also modify the inode and the dindirect block. If we
1509 * are adding a group with superblock/GDT backups we will also
1510 * modify each of the reserved GDT dindirect blocks.
1511 */
1512 credit = 3; /* sb, resize inode, resize inode dindirect */
1513 /* GDT blocks */
1514 credit += 1 + DIV_ROUND_UP(flex_gd->count, EXT4_DESC_PER_BLOCK(sb));
1515 credit += reserved_gdb; /* Reserved GDT dindirect blocks */
1516 handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credit);
1517 if (IS_ERR(handle)) {
1518 err = PTR_ERR(handle);
1519 goto exit;
1520 }
1521
1522 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1523 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1524 if (err)
1525 goto exit_journal;
1526
1527 group = flex_gd->groups[0].group;
1528 BUG_ON(group != sbi->s_groups_count);
1529 err = ext4_add_new_descs(handle, sb, group,
1530 resize_inode, flex_gd->count);
1531 if (err)
1532 goto exit_journal;
1533
1534 err = ext4_setup_new_descs(handle, sb, flex_gd);
1535 if (err)
1536 goto exit_journal;
1537
1538 ext4_update_super(sb, flex_gd);
1539
1540 err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1541
1542 exit_journal:
1543 err2 = ext4_journal_stop(handle);
1544 if (!err)
1545 err = err2;
1546
1547 if (!err) {
1548 int gdb_num = group / EXT4_DESC_PER_BLOCK(sb);
1549 int gdb_num_end = ((group + flex_gd->count - 1) /
1550 EXT4_DESC_PER_BLOCK(sb));
1551 int meta_bg = ext4_has_feature_meta_bg(sb);
1552 sector_t old_gdb = 0;
1553
1554 update_backups(sb, ext4_group_first_block_no(sb, 0),
1555 (char *)es, sizeof(struct ext4_super_block), 0);
1556 for (; gdb_num <= gdb_num_end; gdb_num++) {
1557 struct buffer_head *gdb_bh;
1558
1559 gdb_bh = sbi_array_rcu_deref(sbi, s_group_desc,
1560 gdb_num);
1561 if (old_gdb == gdb_bh->b_blocknr)
1562 continue;
1563 update_backups(sb, gdb_bh->b_blocknr, gdb_bh->b_data,
1564 gdb_bh->b_size, meta_bg);
1565 old_gdb = gdb_bh->b_blocknr;
1566 }
1567 }
1568 exit:
1569 return err;
1570 }
1571
ext4_setup_next_flex_gd(struct super_block * sb,struct ext4_new_flex_group_data * flex_gd,ext4_fsblk_t n_blocks_count,unsigned long flexbg_size)1572 static int ext4_setup_next_flex_gd(struct super_block *sb,
1573 struct ext4_new_flex_group_data *flex_gd,
1574 ext4_fsblk_t n_blocks_count,
1575 unsigned long flexbg_size)
1576 {
1577 struct ext4_sb_info *sbi = EXT4_SB(sb);
1578 struct ext4_super_block *es = sbi->s_es;
1579 struct ext4_new_group_data *group_data = flex_gd->groups;
1580 ext4_fsblk_t o_blocks_count;
1581 ext4_group_t n_group;
1582 ext4_group_t group;
1583 ext4_group_t last_group;
1584 ext4_grpblk_t last;
1585 ext4_grpblk_t clusters_per_group;
1586 unsigned long i;
1587
1588 clusters_per_group = EXT4_CLUSTERS_PER_GROUP(sb);
1589
1590 o_blocks_count = ext4_blocks_count(es);
1591
1592 if (o_blocks_count == n_blocks_count)
1593 return 0;
1594
1595 ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1596 BUG_ON(last);
1597 ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &last);
1598
1599 last_group = group | (flexbg_size - 1);
1600 if (last_group > n_group)
1601 last_group = n_group;
1602
1603 flex_gd->count = last_group - group + 1;
1604
1605 for (i = 0; i < flex_gd->count; i++) {
1606 int overhead;
1607
1608 group_data[i].group = group + i;
1609 group_data[i].blocks_count = EXT4_BLOCKS_PER_GROUP(sb);
1610 overhead = ext4_group_overhead_blocks(sb, group + i);
1611 group_data[i].mdata_blocks = overhead;
1612 group_data[i].free_clusters_count = EXT4_CLUSTERS_PER_GROUP(sb);
1613 if (ext4_has_group_desc_csum(sb)) {
1614 flex_gd->bg_flags[i] = EXT4_BG_BLOCK_UNINIT |
1615 EXT4_BG_INODE_UNINIT;
1616 if (!test_opt(sb, INIT_INODE_TABLE))
1617 flex_gd->bg_flags[i] |= EXT4_BG_INODE_ZEROED;
1618 } else
1619 flex_gd->bg_flags[i] = EXT4_BG_INODE_ZEROED;
1620 }
1621
1622 if (last_group == n_group && ext4_has_group_desc_csum(sb))
1623 /* We need to initialize block bitmap of last group. */
1624 flex_gd->bg_flags[i - 1] &= ~EXT4_BG_BLOCK_UNINIT;
1625
1626 if ((last_group == n_group) && (last != clusters_per_group - 1)) {
1627 group_data[i - 1].blocks_count = EXT4_C2B(sbi, last + 1);
1628 group_data[i - 1].free_clusters_count -= clusters_per_group -
1629 last - 1;
1630 }
1631
1632 return 1;
1633 }
1634
1635 /* Add group descriptor data to an existing or new group descriptor block.
1636 * Ensure we handle all possible error conditions _before_ we start modifying
1637 * the filesystem, because we cannot abort the transaction and not have it
1638 * write the data to disk.
1639 *
1640 * If we are on a GDT block boundary, we need to get the reserved GDT block.
1641 * Otherwise, we may need to add backup GDT blocks for a sparse group.
1642 *
1643 * We only need to hold the superblock lock while we are actually adding
1644 * in the new group's counts to the superblock. Prior to that we have
1645 * not really "added" the group at all. We re-check that we are still
1646 * adding in the last group in case things have changed since verifying.
1647 */
ext4_group_add(struct super_block * sb,struct ext4_new_group_data * input)1648 int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
1649 {
1650 struct ext4_new_flex_group_data flex_gd;
1651 struct ext4_sb_info *sbi = EXT4_SB(sb);
1652 struct ext4_super_block *es = sbi->s_es;
1653 int reserved_gdb = ext4_bg_has_super(sb, input->group) ?
1654 le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
1655 struct inode *inode = NULL;
1656 int gdb_off;
1657 int err;
1658 __u16 bg_flags = 0;
1659
1660 gdb_off = input->group % EXT4_DESC_PER_BLOCK(sb);
1661
1662 if (gdb_off == 0 && !ext4_has_feature_sparse_super(sb)) {
1663 ext4_warning(sb, "Can't resize non-sparse filesystem further");
1664 return -EPERM;
1665 }
1666
1667 if (ext4_blocks_count(es) + input->blocks_count <
1668 ext4_blocks_count(es)) {
1669 ext4_warning(sb, "blocks_count overflow");
1670 return -EINVAL;
1671 }
1672
1673 if (le32_to_cpu(es->s_inodes_count) + EXT4_INODES_PER_GROUP(sb) <
1674 le32_to_cpu(es->s_inodes_count)) {
1675 ext4_warning(sb, "inodes_count overflow");
1676 return -EINVAL;
1677 }
1678
1679 if (reserved_gdb || gdb_off == 0) {
1680 if (!ext4_has_feature_resize_inode(sb) ||
1681 !le16_to_cpu(es->s_reserved_gdt_blocks)) {
1682 ext4_warning(sb,
1683 "No reserved GDT blocks, can't resize");
1684 return -EPERM;
1685 }
1686 inode = ext4_iget(sb, EXT4_RESIZE_INO, EXT4_IGET_SPECIAL);
1687 if (IS_ERR(inode)) {
1688 ext4_warning(sb, "Error opening resize inode");
1689 return PTR_ERR(inode);
1690 }
1691 }
1692
1693
1694 err = verify_group_input(sb, input);
1695 if (err)
1696 goto out;
1697
1698 err = ext4_alloc_flex_bg_array(sb, input->group + 1);
1699 if (err)
1700 goto out;
1701
1702 err = ext4_mb_alloc_groupinfo(sb, input->group + 1);
1703 if (err)
1704 goto out;
1705
1706 flex_gd.count = 1;
1707 flex_gd.groups = input;
1708 flex_gd.bg_flags = &bg_flags;
1709 err = ext4_flex_group_add(sb, inode, &flex_gd);
1710 out:
1711 iput(inode);
1712 return err;
1713 } /* ext4_group_add */
1714
1715 /*
1716 * extend a group without checking assuming that checking has been done.
1717 */
ext4_group_extend_no_check(struct super_block * sb,ext4_fsblk_t o_blocks_count,ext4_grpblk_t add)1718 static int ext4_group_extend_no_check(struct super_block *sb,
1719 ext4_fsblk_t o_blocks_count, ext4_grpblk_t add)
1720 {
1721 struct ext4_super_block *es = EXT4_SB(sb)->s_es;
1722 handle_t *handle;
1723 int err = 0, err2;
1724
1725 /* We will update the superblock, one block bitmap, and
1726 * one group descriptor via ext4_group_add_blocks().
1727 */
1728 handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, 3);
1729 if (IS_ERR(handle)) {
1730 err = PTR_ERR(handle);
1731 ext4_warning(sb, "error %d on journal start", err);
1732 return err;
1733 }
1734
1735 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access");
1736 err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
1737 if (err) {
1738 ext4_warning(sb, "error %d on journal write access", err);
1739 goto errout;
1740 }
1741
1742 lock_buffer(EXT4_SB(sb)->s_sbh);
1743 ext4_blocks_count_set(es, o_blocks_count + add);
1744 ext4_free_blocks_count_set(es, ext4_free_blocks_count(es) + add);
1745 ext4_superblock_csum_set(sb);
1746 unlock_buffer(EXT4_SB(sb)->s_sbh);
1747 ext4_debug("freeing blocks %llu through %llu\n", o_blocks_count,
1748 o_blocks_count + add);
1749 /* We add the blocks to the bitmap and set the group need init bit */
1750 err = ext4_group_add_blocks(handle, sb, o_blocks_count, add);
1751 if (err)
1752 goto errout;
1753 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh);
1754 ext4_debug("freed blocks %llu through %llu\n", o_blocks_count,
1755 o_blocks_count + add);
1756 errout:
1757 err2 = ext4_journal_stop(handle);
1758 if (err2 && !err)
1759 err = err2;
1760
1761 if (!err) {
1762 if (test_opt(sb, DEBUG))
1763 printk(KERN_DEBUG "EXT4-fs: extended group to %llu "
1764 "blocks\n", ext4_blocks_count(es));
1765 update_backups(sb, ext4_group_first_block_no(sb, 0),
1766 (char *)es, sizeof(struct ext4_super_block), 0);
1767 }
1768 return err;
1769 }
1770
1771 /*
1772 * Extend the filesystem to the new number of blocks specified. This entry
1773 * point is only used to extend the current filesystem to the end of the last
1774 * existing group. It can be accessed via ioctl, or by "remount,resize=<size>"
1775 * for emergencies (because it has no dependencies on reserved blocks).
1776 *
1777 * If we _really_ wanted, we could use default values to call ext4_group_add()
1778 * allow the "remount" trick to work for arbitrary resizing, assuming enough
1779 * GDT blocks are reserved to grow to the desired size.
1780 */
ext4_group_extend(struct super_block * sb,struct ext4_super_block * es,ext4_fsblk_t n_blocks_count)1781 int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
1782 ext4_fsblk_t n_blocks_count)
1783 {
1784 ext4_fsblk_t o_blocks_count;
1785 ext4_grpblk_t last;
1786 ext4_grpblk_t add;
1787 struct buffer_head *bh;
1788 int err;
1789 ext4_group_t group;
1790
1791 o_blocks_count = ext4_blocks_count(es);
1792
1793 if (test_opt(sb, DEBUG))
1794 ext4_msg(sb, KERN_DEBUG,
1795 "extending last group from %llu to %llu blocks",
1796 o_blocks_count, n_blocks_count);
1797
1798 if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
1799 return 0;
1800
1801 if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
1802 ext4_msg(sb, KERN_ERR,
1803 "filesystem too large to resize to %llu blocks safely",
1804 n_blocks_count);
1805 return -EINVAL;
1806 }
1807
1808 if (n_blocks_count < o_blocks_count) {
1809 ext4_warning(sb, "can't shrink FS - resize aborted");
1810 return -EINVAL;
1811 }
1812
1813 /* Handle the remaining blocks in the last group only. */
1814 ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
1815
1816 if (last == 0) {
1817 ext4_warning(sb, "need to use ext2online to resize further");
1818 return -EPERM;
1819 }
1820
1821 add = EXT4_BLOCKS_PER_GROUP(sb) - last;
1822
1823 if (o_blocks_count + add < o_blocks_count) {
1824 ext4_warning(sb, "blocks_count overflow");
1825 return -EINVAL;
1826 }
1827
1828 if (o_blocks_count + add > n_blocks_count)
1829 add = n_blocks_count - o_blocks_count;
1830
1831 if (o_blocks_count + add < n_blocks_count)
1832 ext4_warning(sb, "will only finish group (%llu blocks, %u new)",
1833 o_blocks_count + add, add);
1834
1835 /* See if the device is actually as big as what was requested */
1836 bh = ext4_sb_bread(sb, o_blocks_count + add - 1, 0);
1837 if (IS_ERR(bh)) {
1838 ext4_warning(sb, "can't read last block, resize aborted");
1839 return -ENOSPC;
1840 }
1841 brelse(bh);
1842
1843 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
1844 return err;
1845 } /* ext4_group_extend */
1846
1847
num_desc_blocks(struct super_block * sb,ext4_group_t groups)1848 static int num_desc_blocks(struct super_block *sb, ext4_group_t groups)
1849 {
1850 return (groups + EXT4_DESC_PER_BLOCK(sb) - 1) / EXT4_DESC_PER_BLOCK(sb);
1851 }
1852
1853 /*
1854 * Release the resize inode and drop the resize_inode feature if there
1855 * are no more reserved gdt blocks, and then convert the file system
1856 * to enable meta_bg
1857 */
ext4_convert_meta_bg(struct super_block * sb,struct inode * inode)1858 static int ext4_convert_meta_bg(struct super_block *sb, struct inode *inode)
1859 {
1860 handle_t *handle;
1861 struct ext4_sb_info *sbi = EXT4_SB(sb);
1862 struct ext4_super_block *es = sbi->s_es;
1863 struct ext4_inode_info *ei = EXT4_I(inode);
1864 ext4_fsblk_t nr;
1865 int i, ret, err = 0;
1866 int credits = 1;
1867
1868 ext4_msg(sb, KERN_INFO, "Converting file system to meta_bg");
1869 if (inode) {
1870 if (es->s_reserved_gdt_blocks) {
1871 ext4_error(sb, "Unexpected non-zero "
1872 "s_reserved_gdt_blocks");
1873 return -EPERM;
1874 }
1875
1876 /* Do a quick sanity check of the resize inode */
1877 if (inode->i_blocks != 1 << (inode->i_blkbits -
1878 (9 - sbi->s_cluster_bits)))
1879 goto invalid_resize_inode;
1880 for (i = 0; i < EXT4_N_BLOCKS; i++) {
1881 if (i == EXT4_DIND_BLOCK) {
1882 if (ei->i_data[i])
1883 continue;
1884 else
1885 goto invalid_resize_inode;
1886 }
1887 if (ei->i_data[i])
1888 goto invalid_resize_inode;
1889 }
1890 credits += 3; /* block bitmap, bg descriptor, resize inode */
1891 }
1892
1893 handle = ext4_journal_start_sb(sb, EXT4_HT_RESIZE, credits);
1894 if (IS_ERR(handle))
1895 return PTR_ERR(handle);
1896
1897 BUFFER_TRACE(sbi->s_sbh, "get_write_access");
1898 err = ext4_journal_get_write_access(handle, sbi->s_sbh);
1899 if (err)
1900 goto errout;
1901
1902 lock_buffer(sbi->s_sbh);
1903 ext4_clear_feature_resize_inode(sb);
1904 ext4_set_feature_meta_bg(sb);
1905 sbi->s_es->s_first_meta_bg =
1906 cpu_to_le32(num_desc_blocks(sb, sbi->s_groups_count));
1907 ext4_superblock_csum_set(sb);
1908 unlock_buffer(sbi->s_sbh);
1909
1910 err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
1911 if (err) {
1912 ext4_std_error(sb, err);
1913 goto errout;
1914 }
1915
1916 if (inode) {
1917 nr = le32_to_cpu(ei->i_data[EXT4_DIND_BLOCK]);
1918 ext4_free_blocks(handle, inode, NULL, nr, 1,
1919 EXT4_FREE_BLOCKS_METADATA |
1920 EXT4_FREE_BLOCKS_FORGET);
1921 ei->i_data[EXT4_DIND_BLOCK] = 0;
1922 inode->i_blocks = 0;
1923
1924 err = ext4_mark_inode_dirty(handle, inode);
1925 if (err)
1926 ext4_std_error(sb, err);
1927 }
1928
1929 errout:
1930 ret = ext4_journal_stop(handle);
1931 if (!err)
1932 err = ret;
1933 return ret;
1934
1935 invalid_resize_inode:
1936 ext4_error(sb, "corrupted/inconsistent resize inode");
1937 return -EINVAL;
1938 }
1939
1940 /*
1941 * ext4_resize_fs() resizes a fs to new size specified by @n_blocks_count
1942 *
1943 * @sb: super block of the fs to be resized
1944 * @n_blocks_count: the number of blocks resides in the resized fs
1945 */
ext4_resize_fs(struct super_block * sb,ext4_fsblk_t n_blocks_count)1946 int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
1947 {
1948 struct ext4_new_flex_group_data *flex_gd = NULL;
1949 struct ext4_sb_info *sbi = EXT4_SB(sb);
1950 struct ext4_super_block *es = sbi->s_es;
1951 struct buffer_head *bh;
1952 struct inode *resize_inode = NULL;
1953 ext4_grpblk_t add, offset;
1954 unsigned long n_desc_blocks;
1955 unsigned long o_desc_blocks;
1956 ext4_group_t o_group;
1957 ext4_group_t n_group;
1958 ext4_fsblk_t o_blocks_count;
1959 ext4_fsblk_t n_blocks_count_retry = 0;
1960 unsigned long last_update_time = 0;
1961 int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
1962 int meta_bg;
1963
1964 /* See if the device is actually as big as what was requested */
1965 bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);
1966 if (IS_ERR(bh)) {
1967 ext4_warning(sb, "can't read last block, resize aborted");
1968 return -ENOSPC;
1969 }
1970 brelse(bh);
1971
1972 /*
1973 * For bigalloc, trim the requested size to the nearest cluster
1974 * boundary to avoid creating an unusable filesystem. We do this
1975 * silently, instead of returning an error, to avoid breaking
1976 * callers that blindly resize the filesystem to the full size of
1977 * the underlying block device.
1978 */
1979 if (ext4_has_feature_bigalloc(sb))
1980 n_blocks_count &= ~((1 << EXT4_CLUSTER_BITS(sb)) - 1);
1981
1982 retry:
1983 o_blocks_count = ext4_blocks_count(es);
1984
1985 ext4_msg(sb, KERN_INFO, "resizing filesystem from %llu "
1986 "to %llu blocks", o_blocks_count, n_blocks_count);
1987
1988 if (n_blocks_count < o_blocks_count) {
1989 /* On-line shrinking not supported */
1990 ext4_warning(sb, "can't shrink FS - resize aborted");
1991 return -EINVAL;
1992 }
1993
1994 if (n_blocks_count == o_blocks_count)
1995 /* Nothing need to do */
1996 return 0;
1997
1998 n_group = ext4_get_group_number(sb, n_blocks_count - 1);
1999 if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
2000 ext4_warning(sb, "resize would cause inodes_count overflow");
2001 return -EINVAL;
2002 }
2003 ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
2004
2005 n_desc_blocks = num_desc_blocks(sb, n_group + 1);
2006 o_desc_blocks = num_desc_blocks(sb, sbi->s_groups_count);
2007
2008 meta_bg = ext4_has_feature_meta_bg(sb);
2009
2010 if (ext4_has_feature_resize_inode(sb)) {
2011 if (meta_bg) {
2012 ext4_error(sb, "resize_inode and meta_bg enabled "
2013 "simultaneously");
2014 return -EINVAL;
2015 }
2016 if (n_desc_blocks > o_desc_blocks +
2017 le16_to_cpu(es->s_reserved_gdt_blocks)) {
2018 n_blocks_count_retry = n_blocks_count;
2019 n_desc_blocks = o_desc_blocks +
2020 le16_to_cpu(es->s_reserved_gdt_blocks);
2021 n_group = n_desc_blocks * EXT4_DESC_PER_BLOCK(sb);
2022 n_blocks_count = (ext4_fsblk_t)n_group *
2023 EXT4_BLOCKS_PER_GROUP(sb) +
2024 le32_to_cpu(es->s_first_data_block);
2025 n_group--; /* set to last group number */
2026 }
2027
2028 if (!resize_inode)
2029 resize_inode = ext4_iget(sb, EXT4_RESIZE_INO,
2030 EXT4_IGET_SPECIAL);
2031 if (IS_ERR(resize_inode)) {
2032 ext4_warning(sb, "Error opening resize inode");
2033 return PTR_ERR(resize_inode);
2034 }
2035 }
2036
2037 if ((!resize_inode && !meta_bg) || n_blocks_count == o_blocks_count) {
2038 err = ext4_convert_meta_bg(sb, resize_inode);
2039 if (err)
2040 goto out;
2041 if (resize_inode) {
2042 iput(resize_inode);
2043 resize_inode = NULL;
2044 }
2045 if (n_blocks_count_retry) {
2046 n_blocks_count = n_blocks_count_retry;
2047 n_blocks_count_retry = 0;
2048 goto retry;
2049 }
2050 }
2051
2052 /*
2053 * Make sure the last group has enough space so that it's
2054 * guaranteed to have enough space for all metadata blocks
2055 * that it might need to hold. (We might not need to store
2056 * the inode table blocks in the last block group, but there
2057 * will be cases where this might be needed.)
2058 */
2059 if ((ext4_group_first_block_no(sb, n_group) +
2060 ext4_group_overhead_blocks(sb, n_group) + 2 +
2061 sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) {
2062 n_blocks_count = ext4_group_first_block_no(sb, n_group);
2063 n_group--;
2064 n_blocks_count_retry = 0;
2065 if (resize_inode) {
2066 iput(resize_inode);
2067 resize_inode = NULL;
2068 }
2069 goto retry;
2070 }
2071
2072 /* extend the last group */
2073 if (n_group == o_group)
2074 add = n_blocks_count - o_blocks_count;
2075 else
2076 add = EXT4_C2B(sbi, EXT4_CLUSTERS_PER_GROUP(sb) - (offset + 1));
2077 if (add > 0) {
2078 err = ext4_group_extend_no_check(sb, o_blocks_count, add);
2079 if (err)
2080 goto out;
2081 }
2082
2083 if (ext4_blocks_count(es) == n_blocks_count && n_blocks_count_retry == 0)
2084 goto out;
2085
2086 err = ext4_alloc_flex_bg_array(sb, n_group + 1);
2087 if (err)
2088 goto out;
2089
2090 err = ext4_mb_alloc_groupinfo(sb, n_group + 1);
2091 if (err)
2092 goto out;
2093
2094 flex_gd = alloc_flex_gd(flexbg_size);
2095 if (flex_gd == NULL) {
2096 err = -ENOMEM;
2097 goto out;
2098 }
2099
2100 /* Add flex groups. Note that a regular group is a
2101 * flex group with 1 group.
2102 */
2103 while (ext4_setup_next_flex_gd(sb, flex_gd, n_blocks_count,
2104 flexbg_size)) {
2105 if (jiffies - last_update_time > HZ * 10) {
2106 if (last_update_time)
2107 ext4_msg(sb, KERN_INFO,
2108 "resized to %llu blocks",
2109 ext4_blocks_count(es));
2110 last_update_time = jiffies;
2111 }
2112 if (ext4_alloc_group_tables(sb, flex_gd, flexbg_size) != 0)
2113 break;
2114 err = ext4_flex_group_add(sb, resize_inode, flex_gd);
2115 if (unlikely(err))
2116 break;
2117 }
2118
2119 if (!err && n_blocks_count_retry) {
2120 n_blocks_count = n_blocks_count_retry;
2121 n_blocks_count_retry = 0;
2122 free_flex_gd(flex_gd);
2123 flex_gd = NULL;
2124 if (resize_inode) {
2125 iput(resize_inode);
2126 resize_inode = NULL;
2127 }
2128 goto retry;
2129 }
2130
2131 out:
2132 if (flex_gd)
2133 free_flex_gd(flex_gd);
2134 if (resize_inode != NULL)
2135 iput(resize_inode);
2136 if (err)
2137 ext4_warning(sb, "error (%d) occurred during "
2138 "file system resize", err);
2139 ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
2140 ext4_blocks_count(es));
2141 return err;
2142 }
2143