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1 | /* | |
2 | * linux/fs/ext4/balloc.c | |
3 | * | |
4 | * Copyright (C) 1992, 1993, 1994, 1995 | |
5 | * Remy Card (card@masi.ibp.fr) | |
6 | * Laboratoire MASI - Institut Blaise Pascal | |
7 | * Universite Pierre et Marie Curie (Paris VI) | |
8 | * | |
9 | * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 | |
10 | * Big-endian to little-endian byte-swapping/bitmaps by | |
11 | * David S. Miller (davem@caip.rutgers.edu), 1995 | |
12 | */ | |
13 | ||
14 | #include <linux/time.h> | |
15 | #include <linux/capability.h> | |
16 | #include <linux/fs.h> | |
17 | #include <linux/jbd2.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 the block group number and offset into the block/cluster | |
34 | * allocation bitmap, given a block number | |
35 | */ | |
36 | void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, | |
37 | ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) | |
38 | { | |
39 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; | |
40 | ext4_grpblk_t offset; | |
41 | ||
42 | blocknr = blocknr - le32_to_cpu(es->s_first_data_block); | |
43 | offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> | |
44 | EXT4_SB(sb)->s_cluster_bits; | |
45 | if (offsetp) | |
46 | *offsetp = offset; | |
47 | if (blockgrpp) | |
48 | *blockgrpp = blocknr; | |
49 | ||
50 | } | |
51 | ||
52 | static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block, | |
53 | ext4_group_t block_group) | |
54 | { | |
55 | ext4_group_t actual_group; | |
56 | ext4_get_group_no_and_offset(sb, block, &actual_group, NULL); | |
57 | if (actual_group == block_group) | |
58 | return 1; | |
59 | return 0; | |
60 | } | |
61 | ||
62 | /* Return the number of clusters used for file system metadata; this | |
63 | * represents the overhead needed by the file system. | |
64 | */ | |
65 | unsigned ext4_num_overhead_clusters(struct super_block *sb, | |
66 | ext4_group_t block_group, | |
67 | struct ext4_group_desc *gdp) | |
68 | { | |
69 | unsigned num_clusters; | |
70 | int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; | |
71 | ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); | |
72 | ext4_fsblk_t itbl_blk; | |
73 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
74 | ||
75 | /* This is the number of clusters used by the superblock, | |
76 | * block group descriptors, and reserved block group | |
77 | * descriptor blocks */ | |
78 | num_clusters = ext4_num_base_meta_clusters(sb, block_group); | |
79 | ||
80 | /* | |
81 | * For the allocation bitmaps and inode table, we first need | |
82 | * to check to see if the block is in the block group. If it | |
83 | * is, then check to see if the cluster is already accounted | |
84 | * for in the clusters used for the base metadata cluster, or | |
85 | * if we can increment the base metadata cluster to include | |
86 | * that block. Otherwise, we will have to track the cluster | |
87 | * used for the allocation bitmap or inode table explicitly. | |
88 | * Normally all of these blocks are contiguous, so the special | |
89 | * case handling shouldn't be necessary except for *very* | |
90 | * unusual file system layouts. | |
91 | */ | |
92 | if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { | |
93 | block_cluster = EXT4_B2C(sbi, (start - | |
94 | ext4_block_bitmap(sb, gdp))); | |
95 | if (block_cluster < num_clusters) | |
96 | block_cluster = -1; | |
97 | else if (block_cluster == num_clusters) { | |
98 | num_clusters++; | |
99 | block_cluster = -1; | |
100 | } | |
101 | } | |
102 | ||
103 | if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { | |
104 | inode_cluster = EXT4_B2C(sbi, | |
105 | start - ext4_inode_bitmap(sb, gdp)); | |
106 | if (inode_cluster < num_clusters) | |
107 | inode_cluster = -1; | |
108 | else if (inode_cluster == num_clusters) { | |
109 | num_clusters++; | |
110 | inode_cluster = -1; | |
111 | } | |
112 | } | |
113 | ||
114 | itbl_blk = ext4_inode_table(sb, gdp); | |
115 | for (i = 0; i < sbi->s_itb_per_group; i++) { | |
116 | if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { | |
117 | c = EXT4_B2C(sbi, start - itbl_blk + i); | |
118 | if ((c < num_clusters) || (c == inode_cluster) || | |
119 | (c == block_cluster) || (c == itbl_cluster)) | |
120 | continue; | |
121 | if (c == num_clusters) { | |
122 | num_clusters++; | |
123 | continue; | |
124 | } | |
125 | num_clusters++; | |
126 | itbl_cluster = c; | |
127 | } | |
128 | } | |
129 | ||
130 | if (block_cluster != -1) | |
131 | num_clusters++; | |
132 | if (inode_cluster != -1) | |
133 | num_clusters++; | |
134 | ||
135 | return num_clusters; | |
136 | } | |
137 | ||
138 | static unsigned int num_clusters_in_group(struct super_block *sb, | |
139 | ext4_group_t block_group) | |
140 | { | |
141 | unsigned int blocks; | |
142 | ||
143 | if (block_group == ext4_get_groups_count(sb) - 1) { | |
144 | /* | |
145 | * Even though mke2fs always initializes the first and | |
146 | * last group, just in case some other tool was used, | |
147 | * we need to make sure we calculate the right free | |
148 | * blocks. | |
149 | */ | |
150 | blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - | |
151 | ext4_group_first_block_no(sb, block_group); | |
152 | } else | |
153 | blocks = EXT4_BLOCKS_PER_GROUP(sb); | |
154 | return EXT4_NUM_B2C(EXT4_SB(sb), blocks); | |
155 | } | |
156 | ||
157 | /* Initializes an uninitialized block bitmap */ | |
158 | void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, | |
159 | ext4_group_t block_group, | |
160 | struct ext4_group_desc *gdp) | |
161 | { | |
162 | unsigned int bit, bit_max; | |
163 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
164 | ext4_fsblk_t start, tmp; | |
165 | int flex_bg = 0; | |
166 | ||
167 | J_ASSERT_BH(bh, buffer_locked(bh)); | |
168 | ||
169 | /* If checksum is bad mark all blocks used to prevent allocation | |
170 | * essentially implementing a per-group read-only flag. */ | |
171 | if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { | |
172 | ext4_error(sb, "Checksum bad for group %u", block_group); | |
173 | ext4_free_group_clusters_set(sb, gdp, 0); | |
174 | ext4_free_inodes_set(sb, gdp, 0); | |
175 | ext4_itable_unused_set(sb, gdp, 0); | |
176 | memset(bh->b_data, 0xff, sb->s_blocksize); | |
177 | return; | |
178 | } | |
179 | memset(bh->b_data, 0, sb->s_blocksize); | |
180 | ||
181 | bit_max = ext4_num_base_meta_clusters(sb, block_group); | |
182 | for (bit = 0; bit < bit_max; bit++) | |
183 | ext4_set_bit(bit, bh->b_data); | |
184 | ||
185 | start = ext4_group_first_block_no(sb, block_group); | |
186 | ||
187 | if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) | |
188 | flex_bg = 1; | |
189 | ||
190 | /* Set bits for block and inode bitmaps, and inode table */ | |
191 | tmp = ext4_block_bitmap(sb, gdp); | |
192 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
193 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); | |
194 | ||
195 | tmp = ext4_inode_bitmap(sb, gdp); | |
196 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
197 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); | |
198 | ||
199 | tmp = ext4_inode_table(sb, gdp); | |
200 | for (; tmp < ext4_inode_table(sb, gdp) + | |
201 | sbi->s_itb_per_group; tmp++) { | |
202 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
203 | ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); | |
204 | } | |
205 | ||
206 | /* | |
207 | * Also if the number of blocks within the group is less than | |
208 | * the blocksize * 8 ( which is the size of bitmap ), set rest | |
209 | * of the block bitmap to 1 | |
210 | */ | |
211 | ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), | |
212 | sb->s_blocksize * 8, bh->b_data); | |
213 | } | |
214 | ||
215 | /* Return the number of free blocks in a block group. It is used when | |
216 | * the block bitmap is uninitialized, so we can't just count the bits | |
217 | * in the bitmap. */ | |
218 | unsigned ext4_free_clusters_after_init(struct super_block *sb, | |
219 | ext4_group_t block_group, | |
220 | struct ext4_group_desc *gdp) | |
221 | { | |
222 | return num_clusters_in_group(sb, block_group) - | |
223 | ext4_num_overhead_clusters(sb, block_group, gdp); | |
224 | } | |
225 | ||
226 | /* | |
227 | * The free blocks are managed by bitmaps. A file system contains several | |
228 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
229 | * block for inodes, N blocks for the inode table and data blocks. | |
230 | * | |
231 | * The file system contains group descriptors which are located after the | |
232 | * super block. Each descriptor contains the number of the bitmap block and | |
233 | * the free blocks count in the block. The descriptors are loaded in memory | |
234 | * when a file system is mounted (see ext4_fill_super). | |
235 | */ | |
236 | ||
237 | /** | |
238 | * ext4_get_group_desc() -- load group descriptor from disk | |
239 | * @sb: super block | |
240 | * @block_group: given block group | |
241 | * @bh: pointer to the buffer head to store the block | |
242 | * group descriptor | |
243 | */ | |
244 | struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, | |
245 | ext4_group_t block_group, | |
246 | struct buffer_head **bh) | |
247 | { | |
248 | unsigned int group_desc; | |
249 | unsigned int offset; | |
250 | ext4_group_t ngroups = ext4_get_groups_count(sb); | |
251 | struct ext4_group_desc *desc; | |
252 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
253 | ||
254 | if (block_group >= ngroups) { | |
255 | ext4_error(sb, "block_group >= groups_count - block_group = %u," | |
256 | " groups_count = %u", block_group, ngroups); | |
257 | ||
258 | return NULL; | |
259 | } | |
260 | ||
261 | group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); | |
262 | offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); | |
263 | if (!sbi->s_group_desc[group_desc]) { | |
264 | ext4_error(sb, "Group descriptor not loaded - " | |
265 | "block_group = %u, group_desc = %u, desc = %u", | |
266 | block_group, group_desc, offset); | |
267 | return NULL; | |
268 | } | |
269 | ||
270 | desc = (struct ext4_group_desc *)( | |
271 | (__u8 *)sbi->s_group_desc[group_desc]->b_data + | |
272 | offset * EXT4_DESC_SIZE(sb)); | |
273 | if (bh) | |
274 | *bh = sbi->s_group_desc[group_desc]; | |
275 | return desc; | |
276 | } | |
277 | ||
278 | static int ext4_valid_block_bitmap(struct super_block *sb, | |
279 | struct ext4_group_desc *desc, | |
280 | unsigned int block_group, | |
281 | struct buffer_head *bh) | |
282 | { | |
283 | ext4_grpblk_t offset; | |
284 | ext4_grpblk_t next_zero_bit; | |
285 | ext4_fsblk_t bitmap_blk; | |
286 | ext4_fsblk_t group_first_block; | |
287 | ||
288 | if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { | |
289 | /* with FLEX_BG, the inode/block bitmaps and itable | |
290 | * blocks may not be in the group at all | |
291 | * so the bitmap validation will be skipped for those groups | |
292 | * or it has to also read the block group where the bitmaps | |
293 | * are located to verify they are set. | |
294 | */ | |
295 | return 1; | |
296 | } | |
297 | group_first_block = ext4_group_first_block_no(sb, block_group); | |
298 | ||
299 | /* check whether block bitmap block number is set */ | |
300 | bitmap_blk = ext4_block_bitmap(sb, desc); | |
301 | offset = bitmap_blk - group_first_block; | |
302 | if (!ext4_test_bit(offset, bh->b_data)) | |
303 | /* bad block bitmap */ | |
304 | goto err_out; | |
305 | ||
306 | /* check whether the inode bitmap block number is set */ | |
307 | bitmap_blk = ext4_inode_bitmap(sb, desc); | |
308 | offset = bitmap_blk - group_first_block; | |
309 | if (!ext4_test_bit(offset, bh->b_data)) | |
310 | /* bad block bitmap */ | |
311 | goto err_out; | |
312 | ||
313 | /* check whether the inode table block number is set */ | |
314 | bitmap_blk = ext4_inode_table(sb, desc); | |
315 | offset = bitmap_blk - group_first_block; | |
316 | next_zero_bit = ext4_find_next_zero_bit(bh->b_data, | |
317 | offset + EXT4_SB(sb)->s_itb_per_group, | |
318 | offset); | |
319 | if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group) | |
320 | /* good bitmap for inode tables */ | |
321 | return 1; | |
322 | ||
323 | err_out: | |
324 | ext4_error(sb, "Invalid block bitmap - block_group = %d, block = %llu", | |
325 | block_group, bitmap_blk); | |
326 | return 0; | |
327 | } | |
328 | /** | |
329 | * ext4_read_block_bitmap() | |
330 | * @sb: super block | |
331 | * @block_group: given block group | |
332 | * | |
333 | * Read the bitmap for a given block_group,and validate the | |
334 | * bits for block/inode/inode tables are set in the bitmaps | |
335 | * | |
336 | * Return buffer_head on success or NULL in case of failure. | |
337 | */ | |
338 | struct buffer_head * | |
339 | ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) | |
340 | { | |
341 | struct ext4_group_desc *desc; | |
342 | struct buffer_head *bh; | |
343 | ext4_fsblk_t bitmap_blk; | |
344 | ||
345 | desc = ext4_get_group_desc(sb, block_group, NULL); | |
346 | if (!desc) | |
347 | return NULL; | |
348 | bitmap_blk = ext4_block_bitmap(sb, desc); | |
349 | bh = sb_getblk(sb, bitmap_blk); | |
350 | if (unlikely(!bh)) { | |
351 | ext4_error(sb, "Cannot get buffer for block bitmap - " | |
352 | "block_group = %u, block_bitmap = %llu", | |
353 | block_group, bitmap_blk); | |
354 | return NULL; | |
355 | } | |
356 | ||
357 | if (bitmap_uptodate(bh)) | |
358 | return bh; | |
359 | ||
360 | lock_buffer(bh); | |
361 | if (bitmap_uptodate(bh)) { | |
362 | unlock_buffer(bh); | |
363 | return bh; | |
364 | } | |
365 | ext4_lock_group(sb, block_group); | |
366 | if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { | |
367 | ext4_init_block_bitmap(sb, bh, block_group, desc); | |
368 | set_bitmap_uptodate(bh); | |
369 | set_buffer_uptodate(bh); | |
370 | ext4_unlock_group(sb, block_group); | |
371 | unlock_buffer(bh); | |
372 | return bh; | |
373 | } | |
374 | ext4_unlock_group(sb, block_group); | |
375 | if (buffer_uptodate(bh)) { | |
376 | /* | |
377 | * if not uninit if bh is uptodate, | |
378 | * bitmap is also uptodate | |
379 | */ | |
380 | set_bitmap_uptodate(bh); | |
381 | unlock_buffer(bh); | |
382 | return bh; | |
383 | } | |
384 | /* | |
385 | * submit the buffer_head for reading | |
386 | */ | |
387 | set_buffer_new(bh); | |
388 | trace_ext4_read_block_bitmap_load(sb, block_group); | |
389 | bh->b_end_io = ext4_end_bitmap_read; | |
390 | get_bh(bh); | |
391 | submit_bh(READ, bh); | |
392 | return bh; | |
393 | } | |
394 | ||
395 | /* Returns 0 on success, 1 on error */ | |
396 | int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, | |
397 | struct buffer_head *bh) | |
398 | { | |
399 | struct ext4_group_desc *desc; | |
400 | ||
401 | if (!buffer_new(bh)) | |
402 | return 0; | |
403 | desc = ext4_get_group_desc(sb, block_group, NULL); | |
404 | if (!desc) | |
405 | return 1; | |
406 | wait_on_buffer(bh); | |
407 | if (!buffer_uptodate(bh)) { | |
408 | ext4_error(sb, "Cannot read block bitmap - " | |
409 | "block_group = %u, block_bitmap = %llu", | |
410 | block_group, bh->b_blocknr); | |
411 | return 1; | |
412 | } | |
413 | clear_buffer_new(bh); | |
414 | /* Panic or remount fs read-only if block bitmap is invalid */ | |
415 | ext4_valid_block_bitmap(sb, desc, block_group, bh); | |
416 | return 0; | |
417 | } | |
418 | ||
419 | struct buffer_head * | |
420 | ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) | |
421 | { | |
422 | struct buffer_head *bh; | |
423 | ||
424 | bh = ext4_read_block_bitmap_nowait(sb, block_group); | |
425 | if (ext4_wait_block_bitmap(sb, block_group, bh)) { | |
426 | put_bh(bh); | |
427 | return NULL; | |
428 | } | |
429 | return bh; | |
430 | } | |
431 | ||
432 | /** | |
433 | * ext4_has_free_clusters() | |
434 | * @sbi: in-core super block structure. | |
435 | * @nclusters: number of needed blocks | |
436 | * @flags: flags from ext4_mb_new_blocks() | |
437 | * | |
438 | * Check if filesystem has nclusters free & available for allocation. | |
439 | * On success return 1, return 0 on failure. | |
440 | */ | |
441 | static int ext4_has_free_clusters(struct ext4_sb_info *sbi, | |
442 | s64 nclusters, unsigned int flags) | |
443 | { | |
444 | s64 free_clusters, dirty_clusters, root_clusters; | |
445 | struct percpu_counter *fcc = &sbi->s_freeclusters_counter; | |
446 | struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; | |
447 | ||
448 | free_clusters = percpu_counter_read_positive(fcc); | |
449 | dirty_clusters = percpu_counter_read_positive(dcc); | |
450 | root_clusters = EXT4_B2C(sbi, ext4_r_blocks_count(sbi->s_es)); | |
451 | ||
452 | if (free_clusters - (nclusters + root_clusters + dirty_clusters) < | |
453 | EXT4_FREECLUSTERS_WATERMARK) { | |
454 | free_clusters = EXT4_C2B(sbi, percpu_counter_sum_positive(fcc)); | |
455 | dirty_clusters = percpu_counter_sum_positive(dcc); | |
456 | } | |
457 | /* Check whether we have space after accounting for current | |
458 | * dirty clusters & root reserved clusters. | |
459 | */ | |
460 | if (free_clusters >= ((root_clusters + nclusters) + dirty_clusters)) | |
461 | return 1; | |
462 | ||
463 | /* Hm, nope. Are (enough) root reserved clusters available? */ | |
464 | if (sbi->s_resuid == current_fsuid() || | |
465 | ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) || | |
466 | capable(CAP_SYS_RESOURCE) || | |
467 | (flags & EXT4_MB_USE_ROOT_BLOCKS)) { | |
468 | ||
469 | if (free_clusters >= (nclusters + dirty_clusters)) | |
470 | return 1; | |
471 | } | |
472 | ||
473 | return 0; | |
474 | } | |
475 | ||
476 | int ext4_claim_free_clusters(struct ext4_sb_info *sbi, | |
477 | s64 nclusters, unsigned int flags) | |
478 | { | |
479 | if (ext4_has_free_clusters(sbi, nclusters, flags)) { | |
480 | percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); | |
481 | return 0; | |
482 | } else | |
483 | return -ENOSPC; | |
484 | } | |
485 | ||
486 | /** | |
487 | * ext4_should_retry_alloc() | |
488 | * @sb: super block | |
489 | * @retries number of attemps has been made | |
490 | * | |
491 | * ext4_should_retry_alloc() is called when ENOSPC is returned, and if | |
492 | * it is profitable to retry the operation, this function will wait | |
493 | * for the current or committing transaction to complete, and then | |
494 | * return TRUE. | |
495 | * | |
496 | * if the total number of retries exceed three times, return FALSE. | |
497 | */ | |
498 | int ext4_should_retry_alloc(struct super_block *sb, int *retries) | |
499 | { | |
500 | if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || | |
501 | (*retries)++ > 3 || | |
502 | !EXT4_SB(sb)->s_journal) | |
503 | return 0; | |
504 | ||
505 | jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); | |
506 | ||
507 | return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); | |
508 | } | |
509 | ||
510 | /* | |
511 | * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks | |
512 | * | |
513 | * @handle: handle to this transaction | |
514 | * @inode: file inode | |
515 | * @goal: given target block(filesystem wide) | |
516 | * @count: pointer to total number of clusters needed | |
517 | * @errp: error code | |
518 | * | |
519 | * Return 1st allocated block number on success, *count stores total account | |
520 | * error stores in errp pointer | |
521 | */ | |
522 | ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, | |
523 | ext4_fsblk_t goal, unsigned int flags, | |
524 | unsigned long *count, int *errp) | |
525 | { | |
526 | struct ext4_allocation_request ar; | |
527 | ext4_fsblk_t ret; | |
528 | ||
529 | memset(&ar, 0, sizeof(ar)); | |
530 | /* Fill with neighbour allocated blocks */ | |
531 | ar.inode = inode; | |
532 | ar.goal = goal; | |
533 | ar.len = count ? *count : 1; | |
534 | ar.flags = flags; | |
535 | ||
536 | ret = ext4_mb_new_blocks(handle, &ar, errp); | |
537 | if (count) | |
538 | *count = ar.len; | |
539 | /* | |
540 | * Account for the allocated meta blocks. We will never | |
541 | * fail EDQUOT for metdata, but we do account for it. | |
542 | */ | |
543 | if (!(*errp) && | |
544 | ext4_test_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED)) { | |
545 | spin_lock(&EXT4_I(inode)->i_block_reservation_lock); | |
546 | EXT4_I(inode)->i_allocated_meta_blocks += ar.len; | |
547 | spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); | |
548 | dquot_alloc_block_nofail(inode, | |
549 | EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); | |
550 | } | |
551 | return ret; | |
552 | } | |
553 | ||
554 | /** | |
555 | * ext4_count_free_clusters() -- count filesystem free clusters | |
556 | * @sb: superblock | |
557 | * | |
558 | * Adds up the number of free clusters from each block group. | |
559 | */ | |
560 | ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) | |
561 | { | |
562 | ext4_fsblk_t desc_count; | |
563 | struct ext4_group_desc *gdp; | |
564 | ext4_group_t i; | |
565 | ext4_group_t ngroups = ext4_get_groups_count(sb); | |
566 | #ifdef EXT4FS_DEBUG | |
567 | struct ext4_super_block *es; | |
568 | ext4_fsblk_t bitmap_count; | |
569 | unsigned int x; | |
570 | struct buffer_head *bitmap_bh = NULL; | |
571 | ||
572 | es = EXT4_SB(sb)->s_es; | |
573 | desc_count = 0; | |
574 | bitmap_count = 0; | |
575 | gdp = NULL; | |
576 | ||
577 | for (i = 0; i < ngroups; i++) { | |
578 | gdp = ext4_get_group_desc(sb, i, NULL); | |
579 | if (!gdp) | |
580 | continue; | |
581 | desc_count += ext4_free_group_clusters(sb, gdp); | |
582 | brelse(bitmap_bh); | |
583 | bitmap_bh = ext4_read_block_bitmap(sb, i); | |
584 | if (bitmap_bh == NULL) | |
585 | continue; | |
586 | ||
587 | x = ext4_count_free(bitmap_bh, sb->s_blocksize); | |
588 | printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", | |
589 | i, ext4_free_group_clusters(sb, gdp), x); | |
590 | bitmap_count += x; | |
591 | } | |
592 | brelse(bitmap_bh); | |
593 | printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" | |
594 | ", computed = %llu, %llu\n", | |
595 | EXT4_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), | |
596 | desc_count, bitmap_count); | |
597 | return bitmap_count; | |
598 | #else | |
599 | desc_count = 0; | |
600 | for (i = 0; i < ngroups; i++) { | |
601 | gdp = ext4_get_group_desc(sb, i, NULL); | |
602 | if (!gdp) | |
603 | continue; | |
604 | desc_count += ext4_free_group_clusters(sb, gdp); | |
605 | } | |
606 | ||
607 | return desc_count; | |
608 | #endif | |
609 | } | |
610 | ||
611 | static inline int test_root(ext4_group_t a, int b) | |
612 | { | |
613 | int num = b; | |
614 | ||
615 | while (a > num) | |
616 | num *= b; | |
617 | return num == a; | |
618 | } | |
619 | ||
620 | static int ext4_group_sparse(ext4_group_t group) | |
621 | { | |
622 | if (group <= 1) | |
623 | return 1; | |
624 | if (!(group & 1)) | |
625 | return 0; | |
626 | return (test_root(group, 7) || test_root(group, 5) || | |
627 | test_root(group, 3)); | |
628 | } | |
629 | ||
630 | /** | |
631 | * ext4_bg_has_super - number of blocks used by the superblock in group | |
632 | * @sb: superblock for filesystem | |
633 | * @group: group number to check | |
634 | * | |
635 | * Return the number of blocks used by the superblock (primary or backup) | |
636 | * in this group. Currently this will be only 0 or 1. | |
637 | */ | |
638 | int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) | |
639 | { | |
640 | if (EXT4_HAS_RO_COMPAT_FEATURE(sb, | |
641 | EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
642 | !ext4_group_sparse(group)) | |
643 | return 0; | |
644 | return 1; | |
645 | } | |
646 | ||
647 | static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, | |
648 | ext4_group_t group) | |
649 | { | |
650 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
651 | ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); | |
652 | ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; | |
653 | ||
654 | if (group == first || group == first + 1 || group == last) | |
655 | return 1; | |
656 | return 0; | |
657 | } | |
658 | ||
659 | static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, | |
660 | ext4_group_t group) | |
661 | { | |
662 | if (!ext4_bg_has_super(sb, group)) | |
663 | return 0; | |
664 | ||
665 | if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG)) | |
666 | return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); | |
667 | else | |
668 | return EXT4_SB(sb)->s_gdb_count; | |
669 | } | |
670 | ||
671 | /** | |
672 | * ext4_bg_num_gdb - number of blocks used by the group table in group | |
673 | * @sb: superblock for filesystem | |
674 | * @group: group number to check | |
675 | * | |
676 | * Return the number of blocks used by the group descriptor table | |
677 | * (primary or backup) in this group. In the future there may be a | |
678 | * different number of descriptor blocks in each group. | |
679 | */ | |
680 | unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) | |
681 | { | |
682 | unsigned long first_meta_bg = | |
683 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); | |
684 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
685 | ||
686 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) || | |
687 | metagroup < first_meta_bg) | |
688 | return ext4_bg_num_gdb_nometa(sb, group); | |
689 | ||
690 | return ext4_bg_num_gdb_meta(sb,group); | |
691 | ||
692 | } | |
693 | ||
694 | /* | |
695 | * This function returns the number of file system metadata clusters at | |
696 | * the beginning of a block group, including the reserved gdt blocks. | |
697 | */ | |
698 | static unsigned ext4_num_base_meta_clusters(struct super_block *sb, | |
699 | ext4_group_t block_group) | |
700 | { | |
701 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
702 | unsigned num; | |
703 | ||
704 | /* Check for superblock and gdt backups in this group */ | |
705 | num = ext4_bg_has_super(sb, block_group); | |
706 | ||
707 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || | |
708 | block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * | |
709 | sbi->s_desc_per_block) { | |
710 | if (num) { | |
711 | num += ext4_bg_num_gdb(sb, block_group); | |
712 | num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); | |
713 | } | |
714 | } else { /* For META_BG_BLOCK_GROUPS */ | |
715 | num += ext4_bg_num_gdb(sb, block_group); | |
716 | } | |
717 | return EXT4_NUM_B2C(sbi, num); | |
718 | } | |
719 | /** | |
720 | * ext4_inode_to_goal_block - return a hint for block allocation | |
721 | * @inode: inode for block allocation | |
722 | * | |
723 | * Return the ideal location to start allocating blocks for a | |
724 | * newly created inode. | |
725 | */ | |
726 | ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) | |
727 | { | |
728 | struct ext4_inode_info *ei = EXT4_I(inode); | |
729 | ext4_group_t block_group; | |
730 | ext4_grpblk_t colour; | |
731 | int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); | |
732 | ext4_fsblk_t bg_start; | |
733 | ext4_fsblk_t last_block; | |
734 | ||
735 | block_group = ei->i_block_group; | |
736 | if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { | |
737 | /* | |
738 | * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME | |
739 | * block groups per flexgroup, reserve the first block | |
740 | * group for directories and special files. Regular | |
741 | * files will start at the second block group. This | |
742 | * tends to speed up directory access and improves | |
743 | * fsck times. | |
744 | */ | |
745 | block_group &= ~(flex_size-1); | |
746 | if (S_ISREG(inode->i_mode)) | |
747 | block_group++; | |
748 | } | |
749 | bg_start = ext4_group_first_block_no(inode->i_sb, block_group); | |
750 | last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; | |
751 | ||
752 | /* | |
753 | * If we are doing delayed allocation, we don't need take | |
754 | * colour into account. | |
755 | */ | |
756 | if (test_opt(inode->i_sb, DELALLOC)) | |
757 | return bg_start; | |
758 | ||
759 | if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) | |
760 | colour = (current->pid % 16) * | |
761 | (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); | |
762 | else | |
763 | colour = (current->pid % 16) * ((last_block - bg_start) / 16); | |
764 | return bg_start + colour; | |
765 | } | |
766 |