1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * linux/fs/ext4/balloc.c |
4 | * |
5 | * Copyright (C) 1992, 1993, 1994, 1995 |
6 | * Remy Card (card@masi.ibp.fr) |
7 | * Laboratoire MASI - Institut Blaise Pascal |
8 | * Universite Pierre et Marie Curie (Paris VI) |
9 | * |
10 | * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 |
11 | * Big-endian to little-endian byte-swapping/bitmaps by |
12 | * David S. Miller (davem@caip.rutgers.edu), 1995 |
13 | */ |
14 | |
15 | #include <linux/time.h> |
16 | #include <linux/capability.h> |
17 | #include <linux/fs.h> |
18 | #include <linux/quotaops.h> |
19 | #include <linux/buffer_head.h> |
20 | #include "ext4.h" |
21 | #include "ext4_jbd2.h" |
22 | #include "mballoc.h" |
23 | |
24 | #include <trace/events/ext4.h> |
25 | #include <kunit/static_stub.h> |
26 | |
27 | static unsigned ext4_num_base_meta_clusters(struct super_block *sb, |
28 | ext4_group_t block_group); |
29 | /* |
30 | * balloc.c contains the blocks allocation and deallocation routines |
31 | */ |
32 | |
33 | /* |
34 | * Calculate block group number for a given block number |
35 | */ |
36 | ext4_group_t ext4_get_group_number(struct super_block *sb, |
37 | ext4_fsblk_t block) |
38 | { |
39 | ext4_group_t group; |
40 | |
41 | if (test_opt2(sb, STD_GROUP_SIZE)) |
42 | group = (block - |
43 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> |
44 | (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); |
45 | else |
46 | ext4_get_group_no_and_offset(sb, blocknr: block, blockgrpp: &group, NULL); |
47 | return group; |
48 | } |
49 | |
50 | /* |
51 | * Calculate the block group number and offset into the block/cluster |
52 | * allocation bitmap, given a block number |
53 | */ |
54 | void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, |
55 | ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) |
56 | { |
57 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
58 | ext4_grpblk_t offset; |
59 | |
60 | blocknr = blocknr - le32_to_cpu(es->s_first_data_block); |
61 | offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> |
62 | EXT4_SB(sb)->s_cluster_bits; |
63 | if (offsetp) |
64 | *offsetp = offset; |
65 | if (blockgrpp) |
66 | *blockgrpp = blocknr; |
67 | |
68 | } |
69 | |
70 | /* |
71 | * Check whether the 'block' lives within the 'block_group'. Returns 1 if so |
72 | * and 0 otherwise. |
73 | */ |
74 | static inline int ext4_block_in_group(struct super_block *sb, |
75 | ext4_fsblk_t block, |
76 | ext4_group_t block_group) |
77 | { |
78 | ext4_group_t actual_group; |
79 | |
80 | actual_group = ext4_get_group_number(sb, block); |
81 | return (actual_group == block_group) ? 1 : 0; |
82 | } |
83 | |
84 | /* |
85 | * Return the number of clusters used for file system metadata; this |
86 | * represents the overhead needed by the file system. |
87 | */ |
88 | static unsigned ext4_num_overhead_clusters(struct super_block *sb, |
89 | ext4_group_t block_group, |
90 | struct ext4_group_desc *gdp) |
91 | { |
92 | unsigned base_clusters, num_clusters; |
93 | int block_cluster = -1, inode_cluster; |
94 | int itbl_cluster_start = -1, itbl_cluster_end = -1; |
95 | ext4_fsblk_t start = ext4_group_first_block_no(sb, group_no: block_group); |
96 | ext4_fsblk_t end = start + EXT4_BLOCKS_PER_GROUP(sb) - 1; |
97 | ext4_fsblk_t itbl_blk_start, itbl_blk_end; |
98 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
99 | |
100 | /* This is the number of clusters used by the superblock, |
101 | * block group descriptors, and reserved block group |
102 | * descriptor blocks */ |
103 | base_clusters = ext4_num_base_meta_clusters(sb, block_group); |
104 | num_clusters = base_clusters; |
105 | |
106 | /* |
107 | * Account and record inode table clusters if any cluster |
108 | * is in the block group, or inode table cluster range is |
109 | * [-1, -1] and won't overlap with block/inode bitmap cluster |
110 | * accounted below. |
111 | */ |
112 | itbl_blk_start = ext4_inode_table(sb, bg: gdp); |
113 | itbl_blk_end = itbl_blk_start + sbi->s_itb_per_group - 1; |
114 | if (itbl_blk_start <= end && itbl_blk_end >= start) { |
115 | itbl_blk_start = max(itbl_blk_start, start); |
116 | itbl_blk_end = min(itbl_blk_end, end); |
117 | |
118 | itbl_cluster_start = EXT4_B2C(sbi, itbl_blk_start - start); |
119 | itbl_cluster_end = EXT4_B2C(sbi, itbl_blk_end - start); |
120 | |
121 | num_clusters += itbl_cluster_end - itbl_cluster_start + 1; |
122 | /* check if border cluster is overlapped */ |
123 | if (itbl_cluster_start == base_clusters - 1) |
124 | num_clusters--; |
125 | } |
126 | |
127 | /* |
128 | * For the allocation bitmaps, we first need to check to see |
129 | * if the block is in the block group. If it is, then check |
130 | * to see if the cluster is already accounted for in the clusters |
131 | * used for the base metadata cluster and inode tables cluster. |
132 | * Normally all of these blocks are contiguous, so the special |
133 | * case handling shouldn't be necessary except for *very* |
134 | * unusual file system layouts. |
135 | */ |
136 | if (ext4_block_in_group(sb, block: ext4_block_bitmap(sb, bg: gdp), block_group)) { |
137 | block_cluster = EXT4_B2C(sbi, |
138 | ext4_block_bitmap(sb, gdp) - start); |
139 | if (block_cluster >= base_clusters && |
140 | (block_cluster < itbl_cluster_start || |
141 | block_cluster > itbl_cluster_end)) |
142 | num_clusters++; |
143 | } |
144 | |
145 | if (ext4_block_in_group(sb, block: ext4_inode_bitmap(sb, bg: gdp), block_group)) { |
146 | inode_cluster = EXT4_B2C(sbi, |
147 | ext4_inode_bitmap(sb, gdp) - start); |
148 | /* |
149 | * Additional check if inode bitmap is in just accounted |
150 | * block_cluster |
151 | */ |
152 | if (inode_cluster != block_cluster && |
153 | inode_cluster >= base_clusters && |
154 | (inode_cluster < itbl_cluster_start || |
155 | inode_cluster > itbl_cluster_end)) |
156 | num_clusters++; |
157 | } |
158 | |
159 | return num_clusters; |
160 | } |
161 | |
162 | static unsigned int num_clusters_in_group(struct super_block *sb, |
163 | ext4_group_t block_group) |
164 | { |
165 | unsigned int blocks; |
166 | |
167 | if (block_group == ext4_get_groups_count(sb) - 1) { |
168 | /* |
169 | * Even though mke2fs always initializes the first and |
170 | * last group, just in case some other tool was used, |
171 | * we need to make sure we calculate the right free |
172 | * blocks. |
173 | */ |
174 | blocks = ext4_blocks_count(es: EXT4_SB(sb)->s_es) - |
175 | ext4_group_first_block_no(sb, group_no: block_group); |
176 | } else |
177 | blocks = EXT4_BLOCKS_PER_GROUP(sb); |
178 | return EXT4_NUM_B2C(EXT4_SB(sb), blocks); |
179 | } |
180 | |
181 | /* Initializes an uninitialized block bitmap */ |
182 | static int ext4_init_block_bitmap(struct super_block *sb, |
183 | struct buffer_head *bh, |
184 | ext4_group_t block_group, |
185 | struct ext4_group_desc *gdp) |
186 | { |
187 | unsigned int bit, bit_max; |
188 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
189 | ext4_fsblk_t start, tmp; |
190 | |
191 | ASSERT(buffer_locked(bh)); |
192 | |
193 | if (!ext4_group_desc_csum_verify(sb, group: block_group, gdp)) { |
194 | ext4_mark_group_bitmap_corrupted(sb, block_group, |
195 | EXT4_GROUP_INFO_BBITMAP_CORRUPT | |
196 | EXT4_GROUP_INFO_IBITMAP_CORRUPT); |
197 | return -EFSBADCRC; |
198 | } |
199 | memset(bh->b_data, 0, sb->s_blocksize); |
200 | |
201 | bit_max = ext4_num_base_meta_clusters(sb, block_group); |
202 | if ((bit_max >> 3) >= bh->b_size) |
203 | return -EFSCORRUPTED; |
204 | |
205 | for (bit = 0; bit < bit_max; bit++) |
206 | ext4_set_bit(nr: bit, addr: bh->b_data); |
207 | |
208 | start = ext4_group_first_block_no(sb, group_no: block_group); |
209 | |
210 | /* Set bits for block and inode bitmaps, and inode table */ |
211 | tmp = ext4_block_bitmap(sb, bg: gdp); |
212 | if (ext4_block_in_group(sb, block: tmp, block_group)) |
213 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), addr: bh->b_data); |
214 | |
215 | tmp = ext4_inode_bitmap(sb, bg: gdp); |
216 | if (ext4_block_in_group(sb, block: tmp, block_group)) |
217 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), addr: bh->b_data); |
218 | |
219 | tmp = ext4_inode_table(sb, bg: gdp); |
220 | for (; tmp < ext4_inode_table(sb, bg: gdp) + |
221 | sbi->s_itb_per_group; tmp++) { |
222 | if (ext4_block_in_group(sb, block: tmp, block_group)) |
223 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), addr: bh->b_data); |
224 | } |
225 | |
226 | /* |
227 | * Also if the number of blocks within the group is less than |
228 | * the blocksize * 8 ( which is the size of bitmap ), set rest |
229 | * of the block bitmap to 1 |
230 | */ |
231 | ext4_mark_bitmap_end(start_bit: num_clusters_in_group(sb, block_group), |
232 | end_bit: sb->s_blocksize * 8, bitmap: bh->b_data); |
233 | return 0; |
234 | } |
235 | |
236 | /* Return the number of free blocks in a block group. It is used when |
237 | * the block bitmap is uninitialized, so we can't just count the bits |
238 | * in the bitmap. */ |
239 | unsigned ext4_free_clusters_after_init(struct super_block *sb, |
240 | ext4_group_t block_group, |
241 | struct ext4_group_desc *gdp) |
242 | { |
243 | return num_clusters_in_group(sb, block_group) - |
244 | ext4_num_overhead_clusters(sb, block_group, gdp); |
245 | } |
246 | |
247 | /* |
248 | * The free blocks are managed by bitmaps. A file system contains several |
249 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap |
250 | * block for inodes, N blocks for the inode table and data blocks. |
251 | * |
252 | * The file system contains group descriptors which are located after the |
253 | * super block. Each descriptor contains the number of the bitmap block and |
254 | * the free blocks count in the block. The descriptors are loaded in memory |
255 | * when a file system is mounted (see ext4_fill_super). |
256 | */ |
257 | |
258 | /** |
259 | * ext4_get_group_desc() -- load group descriptor from disk |
260 | * @sb: super block |
261 | * @block_group: given block group |
262 | * @bh: pointer to the buffer head to store the block |
263 | * group descriptor |
264 | */ |
265 | struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, |
266 | ext4_group_t block_group, |
267 | struct buffer_head **bh) |
268 | { |
269 | unsigned int group_desc; |
270 | unsigned int offset; |
271 | ext4_group_t ngroups = ext4_get_groups_count(sb); |
272 | struct ext4_group_desc *desc; |
273 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
274 | struct buffer_head *bh_p; |
275 | |
276 | KUNIT_STATIC_STUB_REDIRECT(ext4_get_group_desc, |
277 | sb, block_group, bh); |
278 | |
279 | if (block_group >= ngroups) { |
280 | ext4_error(sb, "block_group >= groups_count - block_group = %u," |
281 | " groups_count = %u" , block_group, ngroups); |
282 | |
283 | return NULL; |
284 | } |
285 | |
286 | group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); |
287 | offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); |
288 | bh_p = sbi_array_rcu_deref(sbi, s_group_desc, group_desc); |
289 | /* |
290 | * sbi_array_rcu_deref returns with rcu unlocked, this is ok since |
291 | * the pointer being dereferenced won't be dereferenced again. By |
292 | * looking at the usage in add_new_gdb() the value isn't modified, |
293 | * just the pointer, and so it remains valid. |
294 | */ |
295 | if (!bh_p) { |
296 | ext4_error(sb, "Group descriptor not loaded - " |
297 | "block_group = %u, group_desc = %u, desc = %u" , |
298 | block_group, group_desc, offset); |
299 | return NULL; |
300 | } |
301 | |
302 | desc = (struct ext4_group_desc *)( |
303 | (__u8 *)bh_p->b_data + |
304 | offset * EXT4_DESC_SIZE(sb)); |
305 | if (bh) |
306 | *bh = bh_p; |
307 | return desc; |
308 | } |
309 | |
310 | static ext4_fsblk_t ext4_valid_block_bitmap_padding(struct super_block *sb, |
311 | ext4_group_t block_group, |
312 | struct buffer_head *bh) |
313 | { |
314 | ext4_grpblk_t next_zero_bit; |
315 | unsigned long bitmap_size = sb->s_blocksize * 8; |
316 | unsigned int offset = num_clusters_in_group(sb, block_group); |
317 | |
318 | if (bitmap_size <= offset) |
319 | return 0; |
320 | |
321 | next_zero_bit = ext4_find_next_zero_bit(addr: bh->b_data, size: bitmap_size, offset); |
322 | |
323 | return (next_zero_bit < bitmap_size ? next_zero_bit : 0); |
324 | } |
325 | |
326 | struct ext4_group_info *ext4_get_group_info(struct super_block *sb, |
327 | ext4_group_t group) |
328 | { |
329 | struct ext4_group_info **grp_info; |
330 | long indexv, indexh; |
331 | |
332 | if (unlikely(group >= EXT4_SB(sb)->s_groups_count)) |
333 | return NULL; |
334 | indexv = group >> (EXT4_DESC_PER_BLOCK_BITS(sb)); |
335 | indexh = group & ((EXT4_DESC_PER_BLOCK(sb)) - 1); |
336 | grp_info = sbi_array_rcu_deref(EXT4_SB(sb), s_group_info, indexv); |
337 | return grp_info[indexh]; |
338 | } |
339 | |
340 | /* |
341 | * Return the block number which was discovered to be invalid, or 0 if |
342 | * the block bitmap is valid. |
343 | */ |
344 | static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, |
345 | struct ext4_group_desc *desc, |
346 | ext4_group_t block_group, |
347 | struct buffer_head *bh) |
348 | { |
349 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
350 | ext4_grpblk_t offset; |
351 | ext4_grpblk_t next_zero_bit; |
352 | ext4_grpblk_t max_bit = EXT4_CLUSTERS_PER_GROUP(sb); |
353 | ext4_fsblk_t blk; |
354 | ext4_fsblk_t group_first_block; |
355 | |
356 | if (ext4_has_feature_flex_bg(sb)) { |
357 | /* with FLEX_BG, the inode/block bitmaps and itable |
358 | * blocks may not be in the group at all |
359 | * so the bitmap validation will be skipped for those groups |
360 | * or it has to also read the block group where the bitmaps |
361 | * are located to verify they are set. |
362 | */ |
363 | return 0; |
364 | } |
365 | group_first_block = ext4_group_first_block_no(sb, group_no: block_group); |
366 | |
367 | /* check whether block bitmap block number is set */ |
368 | blk = ext4_block_bitmap(sb, bg: desc); |
369 | offset = blk - group_first_block; |
370 | if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
371 | !ext4_test_bit(EXT4_B2C(sbi, offset), addr: bh->b_data)) |
372 | /* bad block bitmap */ |
373 | return blk; |
374 | |
375 | /* check whether the inode bitmap block number is set */ |
376 | blk = ext4_inode_bitmap(sb, bg: desc); |
377 | offset = blk - group_first_block; |
378 | if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
379 | !ext4_test_bit(EXT4_B2C(sbi, offset), addr: bh->b_data)) |
380 | /* bad block bitmap */ |
381 | return blk; |
382 | |
383 | /* check whether the inode table block number is set */ |
384 | blk = ext4_inode_table(sb, bg: desc); |
385 | offset = blk - group_first_block; |
386 | if (offset < 0 || EXT4_B2C(sbi, offset) >= max_bit || |
387 | EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) >= max_bit) |
388 | return blk; |
389 | next_zero_bit = ext4_find_next_zero_bit(addr: bh->b_data, |
390 | EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) + 1, |
391 | EXT4_B2C(sbi, offset)); |
392 | if (next_zero_bit < |
393 | EXT4_B2C(sbi, offset + sbi->s_itb_per_group - 1) + 1) |
394 | /* bad bitmap for inode tables */ |
395 | return blk; |
396 | return 0; |
397 | } |
398 | |
399 | static int ext4_validate_block_bitmap(struct super_block *sb, |
400 | struct ext4_group_desc *desc, |
401 | ext4_group_t block_group, |
402 | struct buffer_head *bh) |
403 | { |
404 | ext4_fsblk_t blk; |
405 | struct ext4_group_info *grp; |
406 | |
407 | if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY) |
408 | return 0; |
409 | |
410 | grp = ext4_get_group_info(sb, group: block_group); |
411 | |
412 | if (buffer_verified(bh)) |
413 | return 0; |
414 | if (!grp || EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
415 | return -EFSCORRUPTED; |
416 | |
417 | ext4_lock_group(sb, group: block_group); |
418 | if (buffer_verified(bh)) |
419 | goto verified; |
420 | if (unlikely(!ext4_block_bitmap_csum_verify(sb, desc, bh) || |
421 | ext4_simulate_fail(sb, EXT4_SIM_BBITMAP_CRC))) { |
422 | ext4_unlock_group(sb, group: block_group); |
423 | ext4_error(sb, "bg %u: bad block bitmap checksum" , block_group); |
424 | ext4_mark_group_bitmap_corrupted(sb, block_group, |
425 | EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
426 | return -EFSBADCRC; |
427 | } |
428 | blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); |
429 | if (unlikely(blk != 0)) { |
430 | ext4_unlock_group(sb, group: block_group); |
431 | ext4_error(sb, "bg %u: block %llu: invalid block bitmap" , |
432 | block_group, blk); |
433 | ext4_mark_group_bitmap_corrupted(sb, block_group, |
434 | EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
435 | return -EFSCORRUPTED; |
436 | } |
437 | blk = ext4_valid_block_bitmap_padding(sb, block_group, bh); |
438 | if (unlikely(blk != 0)) { |
439 | ext4_unlock_group(sb, group: block_group); |
440 | ext4_error(sb, "bg %u: block %llu: padding at end of block bitmap is not set" , |
441 | block_group, blk); |
442 | ext4_mark_group_bitmap_corrupted(sb, block_group, |
443 | EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
444 | return -EFSCORRUPTED; |
445 | } |
446 | set_buffer_verified(bh); |
447 | verified: |
448 | ext4_unlock_group(sb, group: block_group); |
449 | return 0; |
450 | } |
451 | |
452 | /** |
453 | * ext4_read_block_bitmap_nowait() |
454 | * @sb: super block |
455 | * @block_group: given block group |
456 | * @ignore_locked: ignore locked buffers |
457 | * |
458 | * Read the bitmap for a given block_group,and validate the |
459 | * bits for block/inode/inode tables are set in the bitmaps |
460 | * |
461 | * Return buffer_head on success or an ERR_PTR in case of failure. |
462 | */ |
463 | struct buffer_head * |
464 | ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group, |
465 | bool ignore_locked) |
466 | { |
467 | struct ext4_group_desc *desc; |
468 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
469 | struct buffer_head *bh; |
470 | ext4_fsblk_t bitmap_blk; |
471 | int err; |
472 | |
473 | KUNIT_STATIC_STUB_REDIRECT(ext4_read_block_bitmap_nowait, |
474 | sb, block_group, ignore_locked); |
475 | |
476 | desc = ext4_get_group_desc(sb, block_group, NULL); |
477 | if (!desc) |
478 | return ERR_PTR(error: -EFSCORRUPTED); |
479 | bitmap_blk = ext4_block_bitmap(sb, bg: desc); |
480 | if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) || |
481 | (bitmap_blk >= ext4_blocks_count(es: sbi->s_es))) { |
482 | ext4_error(sb, "Invalid block bitmap block %llu in " |
483 | "block_group %u" , bitmap_blk, block_group); |
484 | ext4_mark_group_bitmap_corrupted(sb, block_group, |
485 | EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
486 | return ERR_PTR(error: -EFSCORRUPTED); |
487 | } |
488 | bh = sb_getblk(sb, block: bitmap_blk); |
489 | if (unlikely(!bh)) { |
490 | ext4_warning(sb, "Cannot get buffer for block bitmap - " |
491 | "block_group = %u, block_bitmap = %llu" , |
492 | block_group, bitmap_blk); |
493 | return ERR_PTR(error: -ENOMEM); |
494 | } |
495 | |
496 | if (ignore_locked && buffer_locked(bh)) { |
497 | /* buffer under IO already, return if called for prefetching */ |
498 | put_bh(bh); |
499 | return NULL; |
500 | } |
501 | |
502 | if (bitmap_uptodate(bh)) |
503 | goto verify; |
504 | |
505 | lock_buffer(bh); |
506 | if (bitmap_uptodate(bh)) { |
507 | unlock_buffer(bh); |
508 | goto verify; |
509 | } |
510 | ext4_lock_group(sb, group: block_group); |
511 | if (ext4_has_group_desc_csum(sb) && |
512 | (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) { |
513 | if (block_group == 0) { |
514 | ext4_unlock_group(sb, group: block_group); |
515 | unlock_buffer(bh); |
516 | ext4_error(sb, "Block bitmap for bg 0 marked " |
517 | "uninitialized" ); |
518 | err = -EFSCORRUPTED; |
519 | goto out; |
520 | } |
521 | err = ext4_init_block_bitmap(sb, bh, block_group, gdp: desc); |
522 | if (err) { |
523 | ext4_unlock_group(sb, group: block_group); |
524 | unlock_buffer(bh); |
525 | ext4_error(sb, "Failed to init block bitmap for group " |
526 | "%u: %d" , block_group, err); |
527 | goto out; |
528 | } |
529 | set_bitmap_uptodate(bh); |
530 | set_buffer_uptodate(bh); |
531 | set_buffer_verified(bh); |
532 | ext4_unlock_group(sb, group: block_group); |
533 | unlock_buffer(bh); |
534 | return bh; |
535 | } |
536 | ext4_unlock_group(sb, group: block_group); |
537 | if (buffer_uptodate(bh)) { |
538 | /* |
539 | * if not uninit if bh is uptodate, |
540 | * bitmap is also uptodate |
541 | */ |
542 | set_bitmap_uptodate(bh); |
543 | unlock_buffer(bh); |
544 | goto verify; |
545 | } |
546 | /* |
547 | * submit the buffer_head for reading |
548 | */ |
549 | set_buffer_new(bh); |
550 | trace_ext4_read_block_bitmap_load(sb, group: block_group, prefetch: ignore_locked); |
551 | ext4_read_bh_nowait(bh, REQ_META | REQ_PRIO | |
552 | (ignore_locked ? REQ_RAHEAD : 0), |
553 | end_io: ext4_end_bitmap_read); |
554 | return bh; |
555 | verify: |
556 | err = ext4_validate_block_bitmap(sb, desc, block_group, bh); |
557 | if (err) |
558 | goto out; |
559 | return bh; |
560 | out: |
561 | put_bh(bh); |
562 | return ERR_PTR(error: err); |
563 | } |
564 | |
565 | /* Returns 0 on success, -errno on error */ |
566 | int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, |
567 | struct buffer_head *bh) |
568 | { |
569 | struct ext4_group_desc *desc; |
570 | |
571 | KUNIT_STATIC_STUB_REDIRECT(ext4_wait_block_bitmap, |
572 | sb, block_group, bh); |
573 | |
574 | if (!buffer_new(bh)) |
575 | return 0; |
576 | desc = ext4_get_group_desc(sb, block_group, NULL); |
577 | if (!desc) |
578 | return -EFSCORRUPTED; |
579 | wait_on_buffer(bh); |
580 | ext4_simulate_fail_bh(sb, bh, EXT4_SIM_BBITMAP_EIO); |
581 | if (!buffer_uptodate(bh)) { |
582 | ext4_error_err(sb, EIO, "Cannot read block bitmap - " |
583 | "block_group = %u, block_bitmap = %llu" , |
584 | block_group, (unsigned long long) bh->b_blocknr); |
585 | ext4_mark_group_bitmap_corrupted(sb, block_group, |
586 | EXT4_GROUP_INFO_BBITMAP_CORRUPT); |
587 | return -EIO; |
588 | } |
589 | clear_buffer_new(bh); |
590 | /* Panic or remount fs read-only if block bitmap is invalid */ |
591 | return ext4_validate_block_bitmap(sb, desc, block_group, bh); |
592 | } |
593 | |
594 | struct buffer_head * |
595 | ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) |
596 | { |
597 | struct buffer_head *bh; |
598 | int err; |
599 | |
600 | bh = ext4_read_block_bitmap_nowait(sb, block_group, ignore_locked: false); |
601 | if (IS_ERR(ptr: bh)) |
602 | return bh; |
603 | err = ext4_wait_block_bitmap(sb, block_group, bh); |
604 | if (err) { |
605 | put_bh(bh); |
606 | return ERR_PTR(error: err); |
607 | } |
608 | return bh; |
609 | } |
610 | |
611 | /** |
612 | * ext4_has_free_clusters() |
613 | * @sbi: in-core super block structure. |
614 | * @nclusters: number of needed blocks |
615 | * @flags: flags from ext4_mb_new_blocks() |
616 | * |
617 | * Check if filesystem has nclusters free & available for allocation. |
618 | * On success return 1, return 0 on failure. |
619 | */ |
620 | static int ext4_has_free_clusters(struct ext4_sb_info *sbi, |
621 | s64 nclusters, unsigned int flags) |
622 | { |
623 | s64 free_clusters, dirty_clusters, rsv, resv_clusters; |
624 | struct percpu_counter *fcc = &sbi->s_freeclusters_counter; |
625 | struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; |
626 | |
627 | free_clusters = percpu_counter_read_positive(fbc: fcc); |
628 | dirty_clusters = percpu_counter_read_positive(fbc: dcc); |
629 | resv_clusters = atomic64_read(v: &sbi->s_resv_clusters); |
630 | |
631 | /* |
632 | * r_blocks_count should always be multiple of the cluster ratio so |
633 | * we are safe to do a plane bit shift only. |
634 | */ |
635 | rsv = (ext4_r_blocks_count(es: sbi->s_es) >> sbi->s_cluster_bits) + |
636 | resv_clusters; |
637 | |
638 | if (free_clusters - (nclusters + rsv + dirty_clusters) < |
639 | EXT4_FREECLUSTERS_WATERMARK) { |
640 | free_clusters = percpu_counter_sum_positive(fbc: fcc); |
641 | dirty_clusters = percpu_counter_sum_positive(fbc: dcc); |
642 | } |
643 | /* Check whether we have space after accounting for current |
644 | * dirty clusters & root reserved clusters. |
645 | */ |
646 | if (free_clusters >= (rsv + nclusters + dirty_clusters)) |
647 | return 1; |
648 | |
649 | /* Hm, nope. Are (enough) root reserved clusters available? */ |
650 | if (uid_eq(left: sbi->s_resuid, current_fsuid()) || |
651 | (!gid_eq(left: sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || |
652 | capable(CAP_SYS_RESOURCE) || |
653 | (flags & EXT4_MB_USE_ROOT_BLOCKS)) { |
654 | |
655 | if (free_clusters >= (nclusters + dirty_clusters + |
656 | resv_clusters)) |
657 | return 1; |
658 | } |
659 | /* No free blocks. Let's see if we can dip into reserved pool */ |
660 | if (flags & EXT4_MB_USE_RESERVED) { |
661 | if (free_clusters >= (nclusters + dirty_clusters)) |
662 | return 1; |
663 | } |
664 | |
665 | return 0; |
666 | } |
667 | |
668 | int ext4_claim_free_clusters(struct ext4_sb_info *sbi, |
669 | s64 nclusters, unsigned int flags) |
670 | { |
671 | if (ext4_has_free_clusters(sbi, nclusters, flags)) { |
672 | percpu_counter_add(fbc: &sbi->s_dirtyclusters_counter, amount: nclusters); |
673 | return 0; |
674 | } else |
675 | return -ENOSPC; |
676 | } |
677 | |
678 | /** |
679 | * ext4_should_retry_alloc() - check if a block allocation should be retried |
680 | * @sb: superblock |
681 | * @retries: number of retry attempts made so far |
682 | * |
683 | * ext4_should_retry_alloc() is called when ENOSPC is returned while |
684 | * attempting to allocate blocks. If there's an indication that a pending |
685 | * journal transaction might free some space and allow another attempt to |
686 | * succeed, this function will wait for the current or committing transaction |
687 | * to complete and then return TRUE. |
688 | */ |
689 | int ext4_should_retry_alloc(struct super_block *sb, int *retries) |
690 | { |
691 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
692 | |
693 | if (!sbi->s_journal) |
694 | return 0; |
695 | |
696 | if (++(*retries) > 3) { |
697 | percpu_counter_inc(fbc: &sbi->s_sra_exceeded_retry_limit); |
698 | return 0; |
699 | } |
700 | |
701 | /* |
702 | * if there's no indication that blocks are about to be freed it's |
703 | * possible we just missed a transaction commit that did so |
704 | */ |
705 | smp_mb(); |
706 | if (sbi->s_mb_free_pending == 0) { |
707 | if (test_opt(sb, DISCARD)) { |
708 | atomic_inc(v: &sbi->s_retry_alloc_pending); |
709 | flush_work(work: &sbi->s_discard_work); |
710 | atomic_dec(v: &sbi->s_retry_alloc_pending); |
711 | } |
712 | return ext4_has_free_clusters(sbi, nclusters: 1, flags: 0); |
713 | } |
714 | |
715 | /* |
716 | * it's possible we've just missed a transaction commit here, |
717 | * so ignore the returned status |
718 | */ |
719 | ext4_debug("%s: retrying operation after ENOSPC\n" , sb->s_id); |
720 | (void) jbd2_journal_force_commit_nested(sbi->s_journal); |
721 | return 1; |
722 | } |
723 | |
724 | /* |
725 | * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks |
726 | * |
727 | * @handle: handle to this transaction |
728 | * @inode: file inode |
729 | * @goal: given target block(filesystem wide) |
730 | * @count: pointer to total number of clusters needed |
731 | * @errp: error code |
732 | * |
733 | * Return 1st allocated block number on success, *count stores total account |
734 | * error stores in errp pointer |
735 | */ |
736 | ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, |
737 | ext4_fsblk_t goal, unsigned int flags, |
738 | unsigned long *count, int *errp) |
739 | { |
740 | struct ext4_allocation_request ar; |
741 | ext4_fsblk_t ret; |
742 | |
743 | memset(&ar, 0, sizeof(ar)); |
744 | /* Fill with neighbour allocated blocks */ |
745 | ar.inode = inode; |
746 | ar.goal = goal; |
747 | ar.len = count ? *count : 1; |
748 | ar.flags = flags; |
749 | |
750 | ret = ext4_mb_new_blocks(handle, &ar, errp); |
751 | if (count) |
752 | *count = ar.len; |
753 | /* |
754 | * Account for the allocated meta blocks. We will never |
755 | * fail EDQUOT for metdata, but we do account for it. |
756 | */ |
757 | if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { |
758 | dquot_alloc_block_nofail(inode, |
759 | EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); |
760 | } |
761 | return ret; |
762 | } |
763 | |
764 | /** |
765 | * ext4_count_free_clusters() -- count filesystem free clusters |
766 | * @sb: superblock |
767 | * |
768 | * Adds up the number of free clusters from each block group. |
769 | */ |
770 | ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) |
771 | { |
772 | ext4_fsblk_t desc_count; |
773 | struct ext4_group_desc *gdp; |
774 | ext4_group_t i; |
775 | ext4_group_t ngroups = ext4_get_groups_count(sb); |
776 | struct ext4_group_info *grp; |
777 | #ifdef EXT4FS_DEBUG |
778 | struct ext4_super_block *es; |
779 | ext4_fsblk_t bitmap_count; |
780 | unsigned int x; |
781 | struct buffer_head *bitmap_bh = NULL; |
782 | |
783 | es = EXT4_SB(sb)->s_es; |
784 | desc_count = 0; |
785 | bitmap_count = 0; |
786 | gdp = NULL; |
787 | |
788 | for (i = 0; i < ngroups; i++) { |
789 | gdp = ext4_get_group_desc(sb, i, NULL); |
790 | if (!gdp) |
791 | continue; |
792 | grp = NULL; |
793 | if (EXT4_SB(sb)->s_group_info) |
794 | grp = ext4_get_group_info(sb, i); |
795 | if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
796 | desc_count += ext4_free_group_clusters(sb, gdp); |
797 | brelse(bitmap_bh); |
798 | bitmap_bh = ext4_read_block_bitmap(sb, i); |
799 | if (IS_ERR(bitmap_bh)) { |
800 | bitmap_bh = NULL; |
801 | continue; |
802 | } |
803 | |
804 | x = ext4_count_free(bitmap_bh->b_data, |
805 | EXT4_CLUSTERS_PER_GROUP(sb) / 8); |
806 | printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n" , |
807 | i, ext4_free_group_clusters(sb, gdp), x); |
808 | bitmap_count += x; |
809 | } |
810 | brelse(bitmap_bh); |
811 | printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" |
812 | ", computed = %llu, %llu\n" , |
813 | EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), |
814 | desc_count, bitmap_count); |
815 | return bitmap_count; |
816 | #else |
817 | desc_count = 0; |
818 | for (i = 0; i < ngroups; i++) { |
819 | gdp = ext4_get_group_desc(sb, block_group: i, NULL); |
820 | if (!gdp) |
821 | continue; |
822 | grp = NULL; |
823 | if (EXT4_SB(sb)->s_group_info) |
824 | grp = ext4_get_group_info(sb, group: i); |
825 | if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) |
826 | desc_count += ext4_free_group_clusters(sb, bg: gdp); |
827 | } |
828 | |
829 | return desc_count; |
830 | #endif |
831 | } |
832 | |
833 | static inline int test_root(ext4_group_t a, int b) |
834 | { |
835 | while (1) { |
836 | if (a < b) |
837 | return 0; |
838 | if (a == b) |
839 | return 1; |
840 | if ((a % b) != 0) |
841 | return 0; |
842 | a = a / b; |
843 | } |
844 | } |
845 | |
846 | /** |
847 | * ext4_bg_has_super - number of blocks used by the superblock in group |
848 | * @sb: superblock for filesystem |
849 | * @group: group number to check |
850 | * |
851 | * Return the number of blocks used by the superblock (primary or backup) |
852 | * in this group. Currently this will be only 0 or 1. |
853 | */ |
854 | int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) |
855 | { |
856 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; |
857 | |
858 | if (group == 0) |
859 | return 1; |
860 | if (ext4_has_feature_sparse_super2(sb)) { |
861 | if (group == le32_to_cpu(es->s_backup_bgs[0]) || |
862 | group == le32_to_cpu(es->s_backup_bgs[1])) |
863 | return 1; |
864 | return 0; |
865 | } |
866 | if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) |
867 | return 1; |
868 | if (!(group & 1)) |
869 | return 0; |
870 | if (test_root(a: group, b: 3) || (test_root(a: group, b: 5)) || |
871 | test_root(a: group, b: 7)) |
872 | return 1; |
873 | |
874 | return 0; |
875 | } |
876 | |
877 | static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, |
878 | ext4_group_t group) |
879 | { |
880 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
881 | ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); |
882 | ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; |
883 | |
884 | if (group == first || group == first + 1 || group == last) |
885 | return 1; |
886 | return 0; |
887 | } |
888 | |
889 | static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, |
890 | ext4_group_t group) |
891 | { |
892 | if (!ext4_bg_has_super(sb, group)) |
893 | return 0; |
894 | |
895 | if (ext4_has_feature_meta_bg(sb)) |
896 | return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
897 | else |
898 | return EXT4_SB(sb)->s_gdb_count; |
899 | } |
900 | |
901 | /** |
902 | * ext4_bg_num_gdb - number of blocks used by the group table in group |
903 | * @sb: superblock for filesystem |
904 | * @group: group number to check |
905 | * |
906 | * Return the number of blocks used by the group descriptor table |
907 | * (primary or backup) in this group. In the future there may be a |
908 | * different number of descriptor blocks in each group. |
909 | */ |
910 | unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) |
911 | { |
912 | unsigned long first_meta_bg = |
913 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); |
914 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); |
915 | |
916 | if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) |
917 | return ext4_bg_num_gdb_nometa(sb, group); |
918 | |
919 | return ext4_bg_num_gdb_meta(sb,group); |
920 | |
921 | } |
922 | |
923 | /* |
924 | * This function returns the number of file system metadata blocks at |
925 | * the beginning of a block group, including the reserved gdt blocks. |
926 | */ |
927 | unsigned int ext4_num_base_meta_blocks(struct super_block *sb, |
928 | ext4_group_t block_group) |
929 | { |
930 | struct ext4_sb_info *sbi = EXT4_SB(sb); |
931 | unsigned num; |
932 | |
933 | /* Check for superblock and gdt backups in this group */ |
934 | num = ext4_bg_has_super(sb, group: block_group); |
935 | |
936 | if (!ext4_has_feature_meta_bg(sb) || |
937 | block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * |
938 | sbi->s_desc_per_block) { |
939 | if (num) { |
940 | num += ext4_bg_num_gdb_nometa(sb, group: block_group); |
941 | num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); |
942 | } |
943 | } else { /* For META_BG_BLOCK_GROUPS */ |
944 | num += ext4_bg_num_gdb_meta(sb, group: block_group); |
945 | } |
946 | return num; |
947 | } |
948 | |
949 | static unsigned int ext4_num_base_meta_clusters(struct super_block *sb, |
950 | ext4_group_t block_group) |
951 | { |
952 | return EXT4_NUM_B2C(EXT4_SB(sb), ext4_num_base_meta_blocks(sb, block_group)); |
953 | } |
954 | |
955 | /** |
956 | * ext4_inode_to_goal_block - return a hint for block allocation |
957 | * @inode: inode for block allocation |
958 | * |
959 | * Return the ideal location to start allocating blocks for a |
960 | * newly created inode. |
961 | */ |
962 | ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) |
963 | { |
964 | struct ext4_inode_info *ei = EXT4_I(inode); |
965 | ext4_group_t block_group; |
966 | ext4_grpblk_t colour; |
967 | int flex_size = ext4_flex_bg_size(sbi: EXT4_SB(sb: inode->i_sb)); |
968 | ext4_fsblk_t bg_start; |
969 | ext4_fsblk_t last_block; |
970 | |
971 | block_group = ei->i_block_group; |
972 | if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { |
973 | /* |
974 | * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME |
975 | * block groups per flexgroup, reserve the first block |
976 | * group for directories and special files. Regular |
977 | * files will start at the second block group. This |
978 | * tends to speed up directory access and improves |
979 | * fsck times. |
980 | */ |
981 | block_group &= ~(flex_size-1); |
982 | if (S_ISREG(inode->i_mode)) |
983 | block_group++; |
984 | } |
985 | bg_start = ext4_group_first_block_no(sb: inode->i_sb, group_no: block_group); |
986 | last_block = ext4_blocks_count(es: EXT4_SB(sb: inode->i_sb)->s_es) - 1; |
987 | |
988 | /* |
989 | * If we are doing delayed allocation, we don't need take |
990 | * colour into account. |
991 | */ |
992 | if (test_opt(inode->i_sb, DELALLOC)) |
993 | return bg_start; |
994 | |
995 | if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) |
996 | colour = (task_pid_nr(current) % 16) * |
997 | (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); |
998 | else |
999 | colour = (task_pid_nr(current) % 16) * |
1000 | ((last_block - bg_start) / 16); |
1001 | return bg_start + colour; |
1002 | } |
1003 | |
1004 | |