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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 | ||
26 | static unsigned ext4_num_base_meta_clusters(struct super_block *sb, | |
27 | ext4_group_t block_group); | |
28 | /* | |
29 | * balloc.c contains the blocks allocation and deallocation routines | |
30 | */ | |
31 | ||
32 | /* | |
33 | * Calculate block group number for a given block number | |
34 | */ | |
35 | ext4_group_t ext4_get_group_number(struct super_block *sb, | |
36 | ext4_fsblk_t block) | |
37 | { | |
38 | ext4_group_t group; | |
39 | ||
40 | if (test_opt2(sb, STD_GROUP_SIZE)) | |
41 | group = (block - | |
42 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) >> | |
43 | (EXT4_BLOCK_SIZE_BITS(sb) + EXT4_CLUSTER_BITS(sb) + 3); | |
44 | else | |
45 | ext4_get_group_no_and_offset(sb, block, &group, NULL); | |
46 | return group; | |
47 | } | |
48 | ||
49 | /* | |
50 | * Calculate the block group number and offset into the block/cluster | |
51 | * allocation bitmap, given a block number | |
52 | */ | |
53 | void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, | |
54 | ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) | |
55 | { | |
56 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; | |
57 | ext4_grpblk_t offset; | |
58 | ||
59 | blocknr = blocknr - le32_to_cpu(es->s_first_data_block); | |
60 | offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> | |
61 | EXT4_SB(sb)->s_cluster_bits; | |
62 | if (offsetp) | |
63 | *offsetp = offset; | |
64 | if (blockgrpp) | |
65 | *blockgrpp = blocknr; | |
66 | ||
67 | } | |
68 | ||
69 | /* | |
70 | * Check whether the 'block' lives within the 'block_group'. Returns 1 if so | |
71 | * and 0 otherwise. | |
72 | */ | |
73 | static inline int ext4_block_in_group(struct super_block *sb, | |
74 | ext4_fsblk_t block, | |
75 | ext4_group_t block_group) | |
76 | { | |
77 | ext4_group_t actual_group; | |
78 | ||
79 | actual_group = ext4_get_group_number(sb, block); | |
80 | return (actual_group == block_group) ? 1 : 0; | |
81 | } | |
82 | ||
83 | /* Return the number of clusters used for file system metadata; this | |
84 | * represents the overhead needed by the file system. | |
85 | */ | |
86 | static unsigned ext4_num_overhead_clusters(struct super_block *sb, | |
87 | ext4_group_t block_group, | |
88 | struct ext4_group_desc *gdp) | |
89 | { | |
90 | unsigned num_clusters; | |
91 | int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; | |
92 | ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); | |
93 | ext4_fsblk_t itbl_blk; | |
94 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
95 | ||
96 | /* This is the number of clusters used by the superblock, | |
97 | * block group descriptors, and reserved block group | |
98 | * descriptor blocks */ | |
99 | num_clusters = ext4_num_base_meta_clusters(sb, block_group); | |
100 | ||
101 | /* | |
102 | * For the allocation bitmaps and inode table, we first need | |
103 | * to check to see if the block is in the block group. If it | |
104 | * is, then check to see if the cluster is already accounted | |
105 | * for in the clusters used for the base metadata cluster, or | |
106 | * if we can increment the base metadata cluster to include | |
107 | * that block. Otherwise, we will have to track the cluster | |
108 | * used for the allocation bitmap or inode table explicitly. | |
109 | * Normally all of these blocks are contiguous, so the special | |
110 | * case handling shouldn't be necessary except for *very* | |
111 | * unusual file system layouts. | |
112 | */ | |
113 | if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { | |
114 | block_cluster = EXT4_B2C(sbi, | |
115 | ext4_block_bitmap(sb, gdp) - start); | |
116 | if (block_cluster < num_clusters) | |
117 | block_cluster = -1; | |
118 | else if (block_cluster == num_clusters) { | |
119 | num_clusters++; | |
120 | block_cluster = -1; | |
121 | } | |
122 | } | |
123 | ||
124 | if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { | |
125 | inode_cluster = EXT4_B2C(sbi, | |
126 | ext4_inode_bitmap(sb, gdp) - start); | |
127 | if (inode_cluster < num_clusters) | |
128 | inode_cluster = -1; | |
129 | else if (inode_cluster == num_clusters) { | |
130 | num_clusters++; | |
131 | inode_cluster = -1; | |
132 | } | |
133 | } | |
134 | ||
135 | itbl_blk = ext4_inode_table(sb, gdp); | |
136 | for (i = 0; i < sbi->s_itb_per_group; i++) { | |
137 | if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { | |
138 | c = EXT4_B2C(sbi, itbl_blk + i - start); | |
139 | if ((c < num_clusters) || (c == inode_cluster) || | |
140 | (c == block_cluster) || (c == itbl_cluster)) | |
141 | continue; | |
142 | if (c == num_clusters) { | |
143 | num_clusters++; | |
144 | continue; | |
145 | } | |
146 | num_clusters++; | |
147 | itbl_cluster = c; | |
148 | } | |
149 | } | |
150 | ||
151 | if (block_cluster != -1) | |
152 | num_clusters++; | |
153 | if (inode_cluster != -1) | |
154 | num_clusters++; | |
155 | ||
156 | return num_clusters; | |
157 | } | |
158 | ||
159 | static unsigned int num_clusters_in_group(struct super_block *sb, | |
160 | ext4_group_t block_group) | |
161 | { | |
162 | unsigned int blocks; | |
163 | ||
164 | if (block_group == ext4_get_groups_count(sb) - 1) { | |
165 | /* | |
166 | * Even though mke2fs always initializes the first and | |
167 | * last group, just in case some other tool was used, | |
168 | * we need to make sure we calculate the right free | |
169 | * blocks. | |
170 | */ | |
171 | blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - | |
172 | ext4_group_first_block_no(sb, block_group); | |
173 | } else | |
174 | blocks = EXT4_BLOCKS_PER_GROUP(sb); | |
175 | return EXT4_NUM_B2C(EXT4_SB(sb), blocks); | |
176 | } | |
177 | ||
178 | /* Initializes an uninitialized block bitmap */ | |
179 | static int ext4_init_block_bitmap(struct super_block *sb, | |
180 | struct buffer_head *bh, | |
181 | ext4_group_t block_group, | |
182 | struct ext4_group_desc *gdp) | |
183 | { | |
184 | unsigned int bit, bit_max; | |
185 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
186 | ext4_fsblk_t start, tmp; | |
187 | int flex_bg = 0; | |
188 | struct ext4_group_info *grp; | |
189 | ||
190 | J_ASSERT_BH(bh, buffer_locked(bh)); | |
191 | ||
192 | /* If checksum is bad mark all blocks used to prevent allocation | |
193 | * essentially implementing a per-group read-only flag. */ | |
194 | if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) { | |
195 | grp = ext4_get_group_info(sb, block_group); | |
196 | if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
197 | percpu_counter_sub(&sbi->s_freeclusters_counter, | |
198 | grp->bb_free); | |
199 | set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); | |
200 | if (!EXT4_MB_GRP_IBITMAP_CORRUPT(grp)) { | |
201 | int count; | |
202 | count = ext4_free_inodes_count(sb, gdp); | |
203 | percpu_counter_sub(&sbi->s_freeinodes_counter, | |
204 | count); | |
205 | } | |
206 | set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state); | |
207 | return -EFSBADCRC; | |
208 | } | |
209 | memset(bh->b_data, 0, sb->s_blocksize); | |
210 | ||
211 | bit_max = ext4_num_base_meta_clusters(sb, block_group); | |
212 | if ((bit_max >> 3) >= bh->b_size) | |
213 | return -EFSCORRUPTED; | |
214 | ||
215 | for (bit = 0; bit < bit_max; bit++) | |
216 | ext4_set_bit(bit, bh->b_data); | |
217 | ||
218 | start = ext4_group_first_block_no(sb, block_group); | |
219 | ||
220 | if (ext4_has_feature_flex_bg(sb)) | |
221 | flex_bg = 1; | |
222 | ||
223 | /* Set bits for block and inode bitmaps, and inode table */ | |
224 | tmp = ext4_block_bitmap(sb, gdp); | |
225 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
226 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); | |
227 | ||
228 | tmp = ext4_inode_bitmap(sb, gdp); | |
229 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
230 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); | |
231 | ||
232 | tmp = ext4_inode_table(sb, gdp); | |
233 | for (; tmp < ext4_inode_table(sb, gdp) + | |
234 | sbi->s_itb_per_group; tmp++) { | |
235 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
236 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); | |
237 | } | |
238 | ||
239 | /* | |
240 | * Also if the number of blocks within the group is less than | |
241 | * the blocksize * 8 ( which is the size of bitmap ), set rest | |
242 | * of the block bitmap to 1 | |
243 | */ | |
244 | ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), | |
245 | sb->s_blocksize * 8, bh->b_data); | |
246 | ext4_block_bitmap_csum_set(sb, block_group, gdp, bh); | |
247 | ext4_group_desc_csum_set(sb, block_group, gdp); | |
248 | return 0; | |
249 | } | |
250 | ||
251 | /* Return the number of free blocks in a block group. It is used when | |
252 | * the block bitmap is uninitialized, so we can't just count the bits | |
253 | * in the bitmap. */ | |
254 | unsigned ext4_free_clusters_after_init(struct super_block *sb, | |
255 | ext4_group_t block_group, | |
256 | struct ext4_group_desc *gdp) | |
257 | { | |
258 | return num_clusters_in_group(sb, block_group) - | |
259 | ext4_num_overhead_clusters(sb, block_group, gdp); | |
260 | } | |
261 | ||
262 | /* | |
263 | * The free blocks are managed by bitmaps. A file system contains several | |
264 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
265 | * block for inodes, N blocks for the inode table and data blocks. | |
266 | * | |
267 | * The file system contains group descriptors which are located after the | |
268 | * super block. Each descriptor contains the number of the bitmap block and | |
269 | * the free blocks count in the block. The descriptors are loaded in memory | |
270 | * when a file system is mounted (see ext4_fill_super). | |
271 | */ | |
272 | ||
273 | /** | |
274 | * ext4_get_group_desc() -- load group descriptor from disk | |
275 | * @sb: super block | |
276 | * @block_group: given block group | |
277 | * @bh: pointer to the buffer head to store the block | |
278 | * group descriptor | |
279 | */ | |
280 | struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, | |
281 | ext4_group_t block_group, | |
282 | struct buffer_head **bh) | |
283 | { | |
284 | unsigned int group_desc; | |
285 | unsigned int offset; | |
286 | ext4_group_t ngroups = ext4_get_groups_count(sb); | |
287 | struct ext4_group_desc *desc; | |
288 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
289 | ||
290 | if (block_group >= ngroups) { | |
291 | ext4_error(sb, "block_group >= groups_count - block_group = %u," | |
292 | " groups_count = %u", block_group, ngroups); | |
293 | ||
294 | return NULL; | |
295 | } | |
296 | ||
297 | group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); | |
298 | offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); | |
299 | if (!sbi->s_group_desc[group_desc]) { | |
300 | ext4_error(sb, "Group descriptor not loaded - " | |
301 | "block_group = %u, group_desc = %u, desc = %u", | |
302 | block_group, group_desc, offset); | |
303 | return NULL; | |
304 | } | |
305 | ||
306 | desc = (struct ext4_group_desc *)( | |
307 | (__u8 *)sbi->s_group_desc[group_desc]->b_data + | |
308 | offset * EXT4_DESC_SIZE(sb)); | |
309 | if (bh) | |
310 | *bh = sbi->s_group_desc[group_desc]; | |
311 | return desc; | |
312 | } | |
313 | ||
314 | /* | |
315 | * Return the block number which was discovered to be invalid, or 0 if | |
316 | * the block bitmap is valid. | |
317 | */ | |
318 | static ext4_fsblk_t ext4_valid_block_bitmap(struct super_block *sb, | |
319 | struct ext4_group_desc *desc, | |
320 | ext4_group_t block_group, | |
321 | struct buffer_head *bh) | |
322 | { | |
323 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
324 | ext4_grpblk_t offset; | |
325 | ext4_grpblk_t next_zero_bit; | |
326 | ext4_fsblk_t blk; | |
327 | ext4_fsblk_t group_first_block; | |
328 | ||
329 | if (ext4_has_feature_flex_bg(sb)) { | |
330 | /* with FLEX_BG, the inode/block bitmaps and itable | |
331 | * blocks may not be in the group at all | |
332 | * so the bitmap validation will be skipped for those groups | |
333 | * or it has to also read the block group where the bitmaps | |
334 | * are located to verify they are set. | |
335 | */ | |
336 | return 0; | |
337 | } | |
338 | group_first_block = ext4_group_first_block_no(sb, block_group); | |
339 | ||
340 | /* check whether block bitmap block number is set */ | |
341 | blk = ext4_block_bitmap(sb, desc); | |
342 | offset = blk - group_first_block; | |
343 | if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) | |
344 | /* bad block bitmap */ | |
345 | return blk; | |
346 | ||
347 | /* check whether the inode bitmap block number is set */ | |
348 | blk = ext4_inode_bitmap(sb, desc); | |
349 | offset = blk - group_first_block; | |
350 | if (!ext4_test_bit(EXT4_B2C(sbi, offset), bh->b_data)) | |
351 | /* bad block bitmap */ | |
352 | return blk; | |
353 | ||
354 | /* check whether the inode table block number is set */ | |
355 | blk = ext4_inode_table(sb, desc); | |
356 | offset = blk - group_first_block; | |
357 | next_zero_bit = ext4_find_next_zero_bit(bh->b_data, | |
358 | EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group), | |
359 | EXT4_B2C(sbi, offset)); | |
360 | if (next_zero_bit < | |
361 | EXT4_B2C(sbi, offset + EXT4_SB(sb)->s_itb_per_group)) | |
362 | /* bad bitmap for inode tables */ | |
363 | return blk; | |
364 | return 0; | |
365 | } | |
366 | ||
367 | static int ext4_validate_block_bitmap(struct super_block *sb, | |
368 | struct ext4_group_desc *desc, | |
369 | ext4_group_t block_group, | |
370 | struct buffer_head *bh) | |
371 | { | |
372 | ext4_fsblk_t blk; | |
373 | struct ext4_group_info *grp = ext4_get_group_info(sb, block_group); | |
374 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
375 | ||
376 | if (buffer_verified(bh)) | |
377 | return 0; | |
378 | if (EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
379 | return -EFSCORRUPTED; | |
380 | ||
381 | ext4_lock_group(sb, block_group); | |
382 | if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, | |
383 | desc, bh))) { | |
384 | ext4_unlock_group(sb, block_group); | |
385 | ext4_error(sb, "bg %u: bad block bitmap checksum", block_group); | |
386 | if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
387 | percpu_counter_sub(&sbi->s_freeclusters_counter, | |
388 | grp->bb_free); | |
389 | set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); | |
390 | return -EFSBADCRC; | |
391 | } | |
392 | blk = ext4_valid_block_bitmap(sb, desc, block_group, bh); | |
393 | if (unlikely(blk != 0)) { | |
394 | ext4_unlock_group(sb, block_group); | |
395 | ext4_error(sb, "bg %u: block %llu: invalid block bitmap", | |
396 | block_group, blk); | |
397 | if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
398 | percpu_counter_sub(&sbi->s_freeclusters_counter, | |
399 | grp->bb_free); | |
400 | set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); | |
401 | return -EFSCORRUPTED; | |
402 | } | |
403 | set_buffer_verified(bh); | |
404 | ext4_unlock_group(sb, block_group); | |
405 | return 0; | |
406 | } | |
407 | ||
408 | /** | |
409 | * ext4_read_block_bitmap_nowait() | |
410 | * @sb: super block | |
411 | * @block_group: given block group | |
412 | * | |
413 | * Read the bitmap for a given block_group,and validate the | |
414 | * bits for block/inode/inode tables are set in the bitmaps | |
415 | * | |
416 | * Return buffer_head on success or NULL in case of failure. | |
417 | */ | |
418 | struct buffer_head * | |
419 | ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) | |
420 | { | |
421 | struct ext4_group_desc *desc; | |
422 | struct buffer_head *bh; | |
423 | ext4_fsblk_t bitmap_blk; | |
424 | int err; | |
425 | ||
426 | desc = ext4_get_group_desc(sb, block_group, NULL); | |
427 | if (!desc) | |
428 | return ERR_PTR(-EFSCORRUPTED); | |
429 | bitmap_blk = ext4_block_bitmap(sb, desc); | |
430 | bh = sb_getblk(sb, bitmap_blk); | |
431 | if (unlikely(!bh)) { | |
432 | ext4_error(sb, "Cannot get buffer for block bitmap - " | |
433 | "block_group = %u, block_bitmap = %llu", | |
434 | block_group, bitmap_blk); | |
435 | return ERR_PTR(-ENOMEM); | |
436 | } | |
437 | ||
438 | if (bitmap_uptodate(bh)) | |
439 | goto verify; | |
440 | ||
441 | lock_buffer(bh); | |
442 | if (bitmap_uptodate(bh)) { | |
443 | unlock_buffer(bh); | |
444 | goto verify; | |
445 | } | |
446 | ext4_lock_group(sb, block_group); | |
447 | if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { | |
448 | err = ext4_init_block_bitmap(sb, bh, block_group, desc); | |
449 | set_bitmap_uptodate(bh); | |
450 | set_buffer_uptodate(bh); | |
451 | ext4_unlock_group(sb, block_group); | |
452 | unlock_buffer(bh); | |
453 | if (err) { | |
454 | ext4_error(sb, "Failed to init block bitmap for group " | |
455 | "%u: %d", block_group, err); | |
456 | goto out; | |
457 | } | |
458 | goto verify; | |
459 | } | |
460 | ext4_unlock_group(sb, block_group); | |
461 | if (buffer_uptodate(bh)) { | |
462 | /* | |
463 | * if not uninit if bh is uptodate, | |
464 | * bitmap is also uptodate | |
465 | */ | |
466 | set_bitmap_uptodate(bh); | |
467 | unlock_buffer(bh); | |
468 | goto verify; | |
469 | } | |
470 | /* | |
471 | * submit the buffer_head for reading | |
472 | */ | |
473 | set_buffer_new(bh); | |
474 | trace_ext4_read_block_bitmap_load(sb, block_group); | |
475 | bh->b_end_io = ext4_end_bitmap_read; | |
476 | get_bh(bh); | |
477 | submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh); | |
478 | return bh; | |
479 | verify: | |
480 | err = ext4_validate_block_bitmap(sb, desc, block_group, bh); | |
481 | if (err) | |
482 | goto out; | |
483 | return bh; | |
484 | out: | |
485 | put_bh(bh); | |
486 | return ERR_PTR(err); | |
487 | } | |
488 | ||
489 | /* Returns 0 on success, 1 on error */ | |
490 | int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, | |
491 | struct buffer_head *bh) | |
492 | { | |
493 | struct ext4_group_desc *desc; | |
494 | ||
495 | if (!buffer_new(bh)) | |
496 | return 0; | |
497 | desc = ext4_get_group_desc(sb, block_group, NULL); | |
498 | if (!desc) | |
499 | return -EFSCORRUPTED; | |
500 | wait_on_buffer(bh); | |
501 | if (!buffer_uptodate(bh)) { | |
502 | ext4_error(sb, "Cannot read block bitmap - " | |
503 | "block_group = %u, block_bitmap = %llu", | |
504 | block_group, (unsigned long long) bh->b_blocknr); | |
505 | return -EIO; | |
506 | } | |
507 | clear_buffer_new(bh); | |
508 | /* Panic or remount fs read-only if block bitmap is invalid */ | |
509 | return ext4_validate_block_bitmap(sb, desc, block_group, bh); | |
510 | } | |
511 | ||
512 | struct buffer_head * | |
513 | ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) | |
514 | { | |
515 | struct buffer_head *bh; | |
516 | int err; | |
517 | ||
518 | bh = ext4_read_block_bitmap_nowait(sb, block_group); | |
519 | if (IS_ERR(bh)) | |
520 | return bh; | |
521 | err = ext4_wait_block_bitmap(sb, block_group, bh); | |
522 | if (err) { | |
523 | put_bh(bh); | |
524 | return ERR_PTR(err); | |
525 | } | |
526 | return bh; | |
527 | } | |
528 | ||
529 | /** | |
530 | * ext4_has_free_clusters() | |
531 | * @sbi: in-core super block structure. | |
532 | * @nclusters: number of needed blocks | |
533 | * @flags: flags from ext4_mb_new_blocks() | |
534 | * | |
535 | * Check if filesystem has nclusters free & available for allocation. | |
536 | * On success return 1, return 0 on failure. | |
537 | */ | |
538 | static int ext4_has_free_clusters(struct ext4_sb_info *sbi, | |
539 | s64 nclusters, unsigned int flags) | |
540 | { | |
541 | s64 free_clusters, dirty_clusters, rsv, resv_clusters; | |
542 | struct percpu_counter *fcc = &sbi->s_freeclusters_counter; | |
543 | struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; | |
544 | ||
545 | free_clusters = percpu_counter_read_positive(fcc); | |
546 | dirty_clusters = percpu_counter_read_positive(dcc); | |
547 | resv_clusters = atomic64_read(&sbi->s_resv_clusters); | |
548 | ||
549 | /* | |
550 | * r_blocks_count should always be multiple of the cluster ratio so | |
551 | * we are safe to do a plane bit shift only. | |
552 | */ | |
553 | rsv = (ext4_r_blocks_count(sbi->s_es) >> sbi->s_cluster_bits) + | |
554 | resv_clusters; | |
555 | ||
556 | if (free_clusters - (nclusters + rsv + dirty_clusters) < | |
557 | EXT4_FREECLUSTERS_WATERMARK) { | |
558 | free_clusters = percpu_counter_sum_positive(fcc); | |
559 | dirty_clusters = percpu_counter_sum_positive(dcc); | |
560 | } | |
561 | /* Check whether we have space after accounting for current | |
562 | * dirty clusters & root reserved clusters. | |
563 | */ | |
564 | if (free_clusters >= (rsv + nclusters + dirty_clusters)) | |
565 | return 1; | |
566 | ||
567 | /* Hm, nope. Are (enough) root reserved clusters available? */ | |
568 | if (uid_eq(sbi->s_resuid, current_fsuid()) || | |
569 | (!gid_eq(sbi->s_resgid, GLOBAL_ROOT_GID) && in_group_p(sbi->s_resgid)) || | |
570 | capable(CAP_SYS_RESOURCE) || | |
571 | (flags & EXT4_MB_USE_ROOT_BLOCKS)) { | |
572 | ||
573 | if (free_clusters >= (nclusters + dirty_clusters + | |
574 | resv_clusters)) | |
575 | return 1; | |
576 | } | |
577 | /* No free blocks. Let's see if we can dip into reserved pool */ | |
578 | if (flags & EXT4_MB_USE_RESERVED) { | |
579 | if (free_clusters >= (nclusters + dirty_clusters)) | |
580 | return 1; | |
581 | } | |
582 | ||
583 | return 0; | |
584 | } | |
585 | ||
586 | int ext4_claim_free_clusters(struct ext4_sb_info *sbi, | |
587 | s64 nclusters, unsigned int flags) | |
588 | { | |
589 | if (ext4_has_free_clusters(sbi, nclusters, flags)) { | |
590 | percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); | |
591 | return 0; | |
592 | } else | |
593 | return -ENOSPC; | |
594 | } | |
595 | ||
596 | /** | |
597 | * ext4_should_retry_alloc() | |
598 | * @sb: super block | |
599 | * @retries number of attemps has been made | |
600 | * | |
601 | * ext4_should_retry_alloc() is called when ENOSPC is returned, and if | |
602 | * it is profitable to retry the operation, this function will wait | |
603 | * for the current or committing transaction to complete, and then | |
604 | * return TRUE. We will only retry once. | |
605 | */ | |
606 | int ext4_should_retry_alloc(struct super_block *sb, int *retries) | |
607 | { | |
608 | if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || | |
609 | (*retries)++ > 1 || | |
610 | !EXT4_SB(sb)->s_journal) | |
611 | return 0; | |
612 | ||
613 | smp_mb(); | |
614 | if (EXT4_SB(sb)->s_mb_free_pending == 0) | |
615 | return 0; | |
616 | ||
617 | jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); | |
618 | jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); | |
619 | return 1; | |
620 | } | |
621 | ||
622 | /* | |
623 | * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks | |
624 | * | |
625 | * @handle: handle to this transaction | |
626 | * @inode: file inode | |
627 | * @goal: given target block(filesystem wide) | |
628 | * @count: pointer to total number of clusters needed | |
629 | * @errp: error code | |
630 | * | |
631 | * Return 1st allocated block number on success, *count stores total account | |
632 | * error stores in errp pointer | |
633 | */ | |
634 | ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, | |
635 | ext4_fsblk_t goal, unsigned int flags, | |
636 | unsigned long *count, int *errp) | |
637 | { | |
638 | struct ext4_allocation_request ar; | |
639 | ext4_fsblk_t ret; | |
640 | ||
641 | memset(&ar, 0, sizeof(ar)); | |
642 | /* Fill with neighbour allocated blocks */ | |
643 | ar.inode = inode; | |
644 | ar.goal = goal; | |
645 | ar.len = count ? *count : 1; | |
646 | ar.flags = flags; | |
647 | ||
648 | ret = ext4_mb_new_blocks(handle, &ar, errp); | |
649 | if (count) | |
650 | *count = ar.len; | |
651 | /* | |
652 | * Account for the allocated meta blocks. We will never | |
653 | * fail EDQUOT for metdata, but we do account for it. | |
654 | */ | |
655 | if (!(*errp) && (flags & EXT4_MB_DELALLOC_RESERVED)) { | |
656 | dquot_alloc_block_nofail(inode, | |
657 | EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); | |
658 | } | |
659 | return ret; | |
660 | } | |
661 | ||
662 | /** | |
663 | * ext4_count_free_clusters() -- count filesystem free clusters | |
664 | * @sb: superblock | |
665 | * | |
666 | * Adds up the number of free clusters from each block group. | |
667 | */ | |
668 | ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) | |
669 | { | |
670 | ext4_fsblk_t desc_count; | |
671 | struct ext4_group_desc *gdp; | |
672 | ext4_group_t i; | |
673 | ext4_group_t ngroups = ext4_get_groups_count(sb); | |
674 | struct ext4_group_info *grp; | |
675 | #ifdef EXT4FS_DEBUG | |
676 | struct ext4_super_block *es; | |
677 | ext4_fsblk_t bitmap_count; | |
678 | unsigned int x; | |
679 | struct buffer_head *bitmap_bh = NULL; | |
680 | ||
681 | es = EXT4_SB(sb)->s_es; | |
682 | desc_count = 0; | |
683 | bitmap_count = 0; | |
684 | gdp = NULL; | |
685 | ||
686 | for (i = 0; i < ngroups; i++) { | |
687 | gdp = ext4_get_group_desc(sb, i, NULL); | |
688 | if (!gdp) | |
689 | continue; | |
690 | grp = NULL; | |
691 | if (EXT4_SB(sb)->s_group_info) | |
692 | grp = ext4_get_group_info(sb, i); | |
693 | if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
694 | desc_count += ext4_free_group_clusters(sb, gdp); | |
695 | brelse(bitmap_bh); | |
696 | bitmap_bh = ext4_read_block_bitmap(sb, i); | |
697 | if (IS_ERR(bitmap_bh)) { | |
698 | bitmap_bh = NULL; | |
699 | continue; | |
700 | } | |
701 | ||
702 | x = ext4_count_free(bitmap_bh->b_data, | |
703 | EXT4_CLUSTERS_PER_GROUP(sb) / 8); | |
704 | printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", | |
705 | i, ext4_free_group_clusters(sb, gdp), x); | |
706 | bitmap_count += x; | |
707 | } | |
708 | brelse(bitmap_bh); | |
709 | printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" | |
710 | ", computed = %llu, %llu\n", | |
711 | EXT4_NUM_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), | |
712 | desc_count, bitmap_count); | |
713 | return bitmap_count; | |
714 | #else | |
715 | desc_count = 0; | |
716 | for (i = 0; i < ngroups; i++) { | |
717 | gdp = ext4_get_group_desc(sb, i, NULL); | |
718 | if (!gdp) | |
719 | continue; | |
720 | grp = NULL; | |
721 | if (EXT4_SB(sb)->s_group_info) | |
722 | grp = ext4_get_group_info(sb, i); | |
723 | if (!grp || !EXT4_MB_GRP_BBITMAP_CORRUPT(grp)) | |
724 | desc_count += ext4_free_group_clusters(sb, gdp); | |
725 | } | |
726 | ||
727 | return desc_count; | |
728 | #endif | |
729 | } | |
730 | ||
731 | static inline int test_root(ext4_group_t a, int b) | |
732 | { | |
733 | while (1) { | |
734 | if (a < b) | |
735 | return 0; | |
736 | if (a == b) | |
737 | return 1; | |
738 | if ((a % b) != 0) | |
739 | return 0; | |
740 | a = a / b; | |
741 | } | |
742 | } | |
743 | ||
744 | /** | |
745 | * ext4_bg_has_super - number of blocks used by the superblock in group | |
746 | * @sb: superblock for filesystem | |
747 | * @group: group number to check | |
748 | * | |
749 | * Return the number of blocks used by the superblock (primary or backup) | |
750 | * in this group. Currently this will be only 0 or 1. | |
751 | */ | |
752 | int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) | |
753 | { | |
754 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; | |
755 | ||
756 | if (group == 0) | |
757 | return 1; | |
758 | if (ext4_has_feature_sparse_super2(sb)) { | |
759 | if (group == le32_to_cpu(es->s_backup_bgs[0]) || | |
760 | group == le32_to_cpu(es->s_backup_bgs[1])) | |
761 | return 1; | |
762 | return 0; | |
763 | } | |
764 | if ((group <= 1) || !ext4_has_feature_sparse_super(sb)) | |
765 | return 1; | |
766 | if (!(group & 1)) | |
767 | return 0; | |
768 | if (test_root(group, 3) || (test_root(group, 5)) || | |
769 | test_root(group, 7)) | |
770 | return 1; | |
771 | ||
772 | return 0; | |
773 | } | |
774 | ||
775 | static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, | |
776 | ext4_group_t group) | |
777 | { | |
778 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
779 | ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); | |
780 | ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; | |
781 | ||
782 | if (group == first || group == first + 1 || group == last) | |
783 | return 1; | |
784 | return 0; | |
785 | } | |
786 | ||
787 | static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, | |
788 | ext4_group_t group) | |
789 | { | |
790 | if (!ext4_bg_has_super(sb, group)) | |
791 | return 0; | |
792 | ||
793 | if (ext4_has_feature_meta_bg(sb)) | |
794 | return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); | |
795 | else | |
796 | return EXT4_SB(sb)->s_gdb_count; | |
797 | } | |
798 | ||
799 | /** | |
800 | * ext4_bg_num_gdb - number of blocks used by the group table in group | |
801 | * @sb: superblock for filesystem | |
802 | * @group: group number to check | |
803 | * | |
804 | * Return the number of blocks used by the group descriptor table | |
805 | * (primary or backup) in this group. In the future there may be a | |
806 | * different number of descriptor blocks in each group. | |
807 | */ | |
808 | unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) | |
809 | { | |
810 | unsigned long first_meta_bg = | |
811 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); | |
812 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
813 | ||
814 | if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) | |
815 | return ext4_bg_num_gdb_nometa(sb, group); | |
816 | ||
817 | return ext4_bg_num_gdb_meta(sb,group); | |
818 | ||
819 | } | |
820 | ||
821 | /* | |
822 | * This function returns the number of file system metadata clusters at | |
823 | * the beginning of a block group, including the reserved gdt blocks. | |
824 | */ | |
825 | static unsigned ext4_num_base_meta_clusters(struct super_block *sb, | |
826 | ext4_group_t block_group) | |
827 | { | |
828 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
829 | unsigned num; | |
830 | ||
831 | /* Check for superblock and gdt backups in this group */ | |
832 | num = ext4_bg_has_super(sb, block_group); | |
833 | ||
834 | if (!ext4_has_feature_meta_bg(sb) || | |
835 | block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * | |
836 | sbi->s_desc_per_block) { | |
837 | if (num) { | |
838 | num += ext4_bg_num_gdb(sb, block_group); | |
839 | num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); | |
840 | } | |
841 | } else { /* For META_BG_BLOCK_GROUPS */ | |
842 | num += ext4_bg_num_gdb(sb, block_group); | |
843 | } | |
844 | return EXT4_NUM_B2C(sbi, num); | |
845 | } | |
846 | /** | |
847 | * ext4_inode_to_goal_block - return a hint for block allocation | |
848 | * @inode: inode for block allocation | |
849 | * | |
850 | * Return the ideal location to start allocating blocks for a | |
851 | * newly created inode. | |
852 | */ | |
853 | ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) | |
854 | { | |
855 | struct ext4_inode_info *ei = EXT4_I(inode); | |
856 | ext4_group_t block_group; | |
857 | ext4_grpblk_t colour; | |
858 | int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); | |
859 | ext4_fsblk_t bg_start; | |
860 | ext4_fsblk_t last_block; | |
861 | ||
862 | block_group = ei->i_block_group; | |
863 | if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { | |
864 | /* | |
865 | * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME | |
866 | * block groups per flexgroup, reserve the first block | |
867 | * group for directories and special files. Regular | |
868 | * files will start at the second block group. This | |
869 | * tends to speed up directory access and improves | |
870 | * fsck times. | |
871 | */ | |
872 | block_group &= ~(flex_size-1); | |
873 | if (S_ISREG(inode->i_mode)) | |
874 | block_group++; | |
875 | } | |
876 | bg_start = ext4_group_first_block_no(inode->i_sb, block_group); | |
877 | last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; | |
878 | ||
879 | /* | |
880 | * If we are doing delayed allocation, we don't need take | |
881 | * colour into account. | |
882 | */ | |
883 | if (test_opt(inode->i_sb, DELALLOC)) | |
884 | return bg_start; | |
885 | ||
886 | if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) | |
887 | colour = (current->pid % 16) * | |
888 | (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); | |
889 | else | |
890 | colour = (current->pid % 16) * ((last_block - bg_start) / 16); | |
891 | return bg_start + colour; | |
892 | } | |
893 |