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Commit | Line | Data |
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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 | /* | |
25 | * balloc.c contains the blocks allocation and deallocation routines | |
26 | */ | |
27 | ||
28 | /* | |
29 | * Calculate the block group number and offset, given a block number | |
30 | */ | |
31 | void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, | |
32 | ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) | |
33 | { | |
34 | struct ext4_super_block *es = EXT4_SB(sb)->s_es; | |
35 | ext4_grpblk_t offset; | |
36 | ||
37 | blocknr = blocknr - le32_to_cpu(es->s_first_data_block); | |
38 | offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)); | |
39 | if (offsetp) | |
40 | *offsetp = offset; | |
41 | if (blockgrpp) | |
42 | *blockgrpp = blocknr; | |
43 | ||
44 | } | |
45 | ||
46 | static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block, | |
47 | ext4_group_t block_group) | |
48 | { | |
49 | ext4_group_t actual_group; | |
50 | ext4_get_group_no_and_offset(sb, block, &actual_group, NULL); | |
51 | if (actual_group == block_group) | |
52 | return 1; | |
53 | return 0; | |
54 | } | |
55 | ||
56 | static int ext4_group_used_meta_blocks(struct super_block *sb, | |
57 | ext4_group_t block_group, | |
58 | struct ext4_group_desc *gdp) | |
59 | { | |
60 | ext4_fsblk_t tmp; | |
61 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
62 | /* block bitmap, inode bitmap, and inode table blocks */ | |
63 | int used_blocks = sbi->s_itb_per_group + 2; | |
64 | ||
65 | if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { | |
66 | if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), | |
67 | block_group)) | |
68 | used_blocks--; | |
69 | ||
70 | if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), | |
71 | block_group)) | |
72 | used_blocks--; | |
73 | ||
74 | tmp = ext4_inode_table(sb, gdp); | |
75 | for (; tmp < ext4_inode_table(sb, gdp) + | |
76 | sbi->s_itb_per_group; tmp++) { | |
77 | if (!ext4_block_in_group(sb, tmp, block_group)) | |
78 | used_blocks -= 1; | |
79 | } | |
80 | } | |
81 | return used_blocks; | |
82 | } | |
83 | ||
84 | /* Initializes an uninitialized block bitmap if given, and returns the | |
85 | * number of blocks free in the group. */ | |
86 | unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, | |
87 | ext4_group_t block_group, struct ext4_group_desc *gdp) | |
88 | { | |
89 | int bit, bit_max; | |
90 | ext4_group_t ngroups = ext4_get_groups_count(sb); | |
91 | unsigned free_blocks, group_blocks; | |
92 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
93 | ||
94 | if (bh) { | |
95 | J_ASSERT_BH(bh, buffer_locked(bh)); | |
96 | ||
97 | /* If checksum is bad mark all blocks used to prevent allocation | |
98 | * essentially implementing a per-group read-only flag. */ | |
99 | if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { | |
100 | ext4_error(sb, "Checksum bad for group %u", | |
101 | block_group); | |
102 | ext4_free_blks_set(sb, gdp, 0); | |
103 | ext4_free_inodes_set(sb, gdp, 0); | |
104 | ext4_itable_unused_set(sb, gdp, 0); | |
105 | memset(bh->b_data, 0xff, sb->s_blocksize); | |
106 | return 0; | |
107 | } | |
108 | memset(bh->b_data, 0, sb->s_blocksize); | |
109 | } | |
110 | ||
111 | /* Check for superblock and gdt backups in this group */ | |
112 | bit_max = ext4_bg_has_super(sb, block_group); | |
113 | ||
114 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || | |
115 | block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * | |
116 | sbi->s_desc_per_block) { | |
117 | if (bit_max) { | |
118 | bit_max += ext4_bg_num_gdb(sb, block_group); | |
119 | bit_max += | |
120 | le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); | |
121 | } | |
122 | } else { /* For META_BG_BLOCK_GROUPS */ | |
123 | bit_max += ext4_bg_num_gdb(sb, block_group); | |
124 | } | |
125 | ||
126 | if (block_group == ngroups - 1) { | |
127 | /* | |
128 | * Even though mke2fs always initialize first and last group | |
129 | * if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need | |
130 | * to make sure we calculate the right free blocks | |
131 | */ | |
132 | group_blocks = ext4_blocks_count(sbi->s_es) - | |
133 | ext4_group_first_block_no(sb, ngroups - 1); | |
134 | } else { | |
135 | group_blocks = EXT4_BLOCKS_PER_GROUP(sb); | |
136 | } | |
137 | ||
138 | free_blocks = group_blocks - bit_max; | |
139 | ||
140 | if (bh) { | |
141 | ext4_fsblk_t start, tmp; | |
142 | int flex_bg = 0; | |
143 | ||
144 | for (bit = 0; bit < bit_max; bit++) | |
145 | ext4_set_bit(bit, bh->b_data); | |
146 | ||
147 | start = ext4_group_first_block_no(sb, block_group); | |
148 | ||
149 | if (EXT4_HAS_INCOMPAT_FEATURE(sb, | |
150 | EXT4_FEATURE_INCOMPAT_FLEX_BG)) | |
151 | flex_bg = 1; | |
152 | ||
153 | /* Set bits for block and inode bitmaps, and inode table */ | |
154 | tmp = ext4_block_bitmap(sb, gdp); | |
155 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
156 | ext4_set_bit(tmp - start, bh->b_data); | |
157 | ||
158 | tmp = ext4_inode_bitmap(sb, gdp); | |
159 | if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) | |
160 | ext4_set_bit(tmp - start, bh->b_data); | |
161 | ||
162 | tmp = ext4_inode_table(sb, gdp); | |
163 | for (; tmp < ext4_inode_table(sb, gdp) + | |
164 | sbi->s_itb_per_group; tmp++) { | |
165 | if (!flex_bg || | |
166 | ext4_block_in_group(sb, tmp, block_group)) | |
167 | ext4_set_bit(tmp - start, bh->b_data); | |
168 | } | |
169 | /* | |
170 | * Also if the number of blocks within the group is | |
171 | * less than the blocksize * 8 ( which is the size | |
172 | * of bitmap ), set rest of the block bitmap to 1 | |
173 | */ | |
174 | mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data); | |
175 | } | |
176 | return free_blocks - ext4_group_used_meta_blocks(sb, block_group, gdp); | |
177 | } | |
178 | ||
179 | ||
180 | /* | |
181 | * The free blocks are managed by bitmaps. A file system contains several | |
182 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
183 | * block for inodes, N blocks for the inode table and data blocks. | |
184 | * | |
185 | * The file system contains group descriptors which are located after the | |
186 | * super block. Each descriptor contains the number of the bitmap block and | |
187 | * the free blocks count in the block. The descriptors are loaded in memory | |
188 | * when a file system is mounted (see ext4_fill_super). | |
189 | */ | |
190 | ||
191 | /** | |
192 | * ext4_get_group_desc() -- load group descriptor from disk | |
193 | * @sb: super block | |
194 | * @block_group: given block group | |
195 | * @bh: pointer to the buffer head to store the block | |
196 | * group descriptor | |
197 | */ | |
198 | struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, | |
199 | ext4_group_t block_group, | |
200 | struct buffer_head **bh) | |
201 | { | |
202 | unsigned int group_desc; | |
203 | unsigned int offset; | |
204 | ext4_group_t ngroups = ext4_get_groups_count(sb); | |
205 | struct ext4_group_desc *desc; | |
206 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
207 | ||
208 | if (block_group >= ngroups) { | |
209 | ext4_error(sb, "block_group >= groups_count - block_group = %u," | |
210 | " groups_count = %u", block_group, ngroups); | |
211 | ||
212 | return NULL; | |
213 | } | |
214 | ||
215 | group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); | |
216 | offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); | |
217 | if (!sbi->s_group_desc[group_desc]) { | |
218 | ext4_error(sb, "Group descriptor not loaded - " | |
219 | "block_group = %u, group_desc = %u, desc = %u", | |
220 | block_group, group_desc, offset); | |
221 | return NULL; | |
222 | } | |
223 | ||
224 | desc = (struct ext4_group_desc *)( | |
225 | (__u8 *)sbi->s_group_desc[group_desc]->b_data + | |
226 | offset * EXT4_DESC_SIZE(sb)); | |
227 | if (bh) | |
228 | *bh = sbi->s_group_desc[group_desc]; | |
229 | return desc; | |
230 | } | |
231 | ||
232 | static int ext4_valid_block_bitmap(struct super_block *sb, | |
233 | struct ext4_group_desc *desc, | |
234 | unsigned int block_group, | |
235 | struct buffer_head *bh) | |
236 | { | |
237 | ext4_grpblk_t offset; | |
238 | ext4_grpblk_t next_zero_bit; | |
239 | ext4_fsblk_t bitmap_blk; | |
240 | ext4_fsblk_t group_first_block; | |
241 | ||
242 | if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { | |
243 | /* with FLEX_BG, the inode/block bitmaps and itable | |
244 | * blocks may not be in the group at all | |
245 | * so the bitmap validation will be skipped for those groups | |
246 | * or it has to also read the block group where the bitmaps | |
247 | * are located to verify they are set. | |
248 | */ | |
249 | return 1; | |
250 | } | |
251 | group_first_block = ext4_group_first_block_no(sb, block_group); | |
252 | ||
253 | /* check whether block bitmap block number is set */ | |
254 | bitmap_blk = ext4_block_bitmap(sb, desc); | |
255 | offset = bitmap_blk - group_first_block; | |
256 | if (!ext4_test_bit(offset, bh->b_data)) | |
257 | /* bad block bitmap */ | |
258 | goto err_out; | |
259 | ||
260 | /* check whether the inode bitmap block number is set */ | |
261 | bitmap_blk = ext4_inode_bitmap(sb, desc); | |
262 | offset = bitmap_blk - group_first_block; | |
263 | if (!ext4_test_bit(offset, bh->b_data)) | |
264 | /* bad block bitmap */ | |
265 | goto err_out; | |
266 | ||
267 | /* check whether the inode table block number is set */ | |
268 | bitmap_blk = ext4_inode_table(sb, desc); | |
269 | offset = bitmap_blk - group_first_block; | |
270 | next_zero_bit = ext4_find_next_zero_bit(bh->b_data, | |
271 | offset + EXT4_SB(sb)->s_itb_per_group, | |
272 | offset); | |
273 | if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group) | |
274 | /* good bitmap for inode tables */ | |
275 | return 1; | |
276 | ||
277 | err_out: | |
278 | ext4_error(sb, "Invalid block bitmap - block_group = %d, block = %llu", | |
279 | block_group, bitmap_blk); | |
280 | return 0; | |
281 | } | |
282 | /** | |
283 | * ext4_read_block_bitmap() | |
284 | * @sb: super block | |
285 | * @block_group: given block group | |
286 | * | |
287 | * Read the bitmap for a given block_group,and validate the | |
288 | * bits for block/inode/inode tables are set in the bitmaps | |
289 | * | |
290 | * Return buffer_head on success or NULL in case of failure. | |
291 | */ | |
292 | struct buffer_head * | |
293 | ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) | |
294 | { | |
295 | struct ext4_group_desc *desc; | |
296 | struct buffer_head *bh = NULL; | |
297 | ext4_fsblk_t bitmap_blk; | |
298 | ||
299 | desc = ext4_get_group_desc(sb, block_group, NULL); | |
300 | if (!desc) | |
301 | return NULL; | |
302 | bitmap_blk = ext4_block_bitmap(sb, desc); | |
303 | bh = sb_getblk(sb, bitmap_blk); | |
304 | if (unlikely(!bh)) { | |
305 | ext4_error(sb, "Cannot read block bitmap - " | |
306 | "block_group = %u, block_bitmap = %llu", | |
307 | block_group, bitmap_blk); | |
308 | return NULL; | |
309 | } | |
310 | ||
311 | if (bitmap_uptodate(bh)) | |
312 | return bh; | |
313 | ||
314 | lock_buffer(bh); | |
315 | if (bitmap_uptodate(bh)) { | |
316 | unlock_buffer(bh); | |
317 | return bh; | |
318 | } | |
319 | ext4_lock_group(sb, block_group); | |
320 | if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { | |
321 | ext4_init_block_bitmap(sb, bh, block_group, desc); | |
322 | set_bitmap_uptodate(bh); | |
323 | set_buffer_uptodate(bh); | |
324 | ext4_unlock_group(sb, block_group); | |
325 | unlock_buffer(bh); | |
326 | return bh; | |
327 | } | |
328 | ext4_unlock_group(sb, block_group); | |
329 | if (buffer_uptodate(bh)) { | |
330 | /* | |
331 | * if not uninit if bh is uptodate, | |
332 | * bitmap is also uptodate | |
333 | */ | |
334 | set_bitmap_uptodate(bh); | |
335 | unlock_buffer(bh); | |
336 | return bh; | |
337 | } | |
338 | /* | |
339 | * submit the buffer_head for read. We can | |
340 | * safely mark the bitmap as uptodate now. | |
341 | * We do it here so the bitmap uptodate bit | |
342 | * get set with buffer lock held. | |
343 | */ | |
344 | set_bitmap_uptodate(bh); | |
345 | if (bh_submit_read(bh) < 0) { | |
346 | put_bh(bh); | |
347 | ext4_error(sb, "Cannot read block bitmap - " | |
348 | "block_group = %u, block_bitmap = %llu", | |
349 | block_group, bitmap_blk); | |
350 | return NULL; | |
351 | } | |
352 | ext4_valid_block_bitmap(sb, desc, block_group, bh); | |
353 | /* | |
354 | * file system mounted not to panic on error, | |
355 | * continue with corrupt bitmap | |
356 | */ | |
357 | return bh; | |
358 | } | |
359 | ||
360 | /** | |
361 | * ext4_add_groupblocks() -- Add given blocks to an existing group | |
362 | * @handle: handle to this transaction | |
363 | * @sb: super block | |
364 | * @block: start physcial block to add to the block group | |
365 | * @count: number of blocks to free | |
366 | * | |
367 | * This marks the blocks as free in the bitmap. We ask the | |
368 | * mballoc to reload the buddy after this by setting group | |
369 | * EXT4_GROUP_INFO_NEED_INIT_BIT flag | |
370 | */ | |
371 | void ext4_add_groupblocks(handle_t *handle, struct super_block *sb, | |
372 | ext4_fsblk_t block, unsigned long count) | |
373 | { | |
374 | struct buffer_head *bitmap_bh = NULL; | |
375 | struct buffer_head *gd_bh; | |
376 | ext4_group_t block_group; | |
377 | ext4_grpblk_t bit; | |
378 | unsigned int i; | |
379 | struct ext4_group_desc *desc; | |
380 | struct ext4_sb_info *sbi = EXT4_SB(sb); | |
381 | int err = 0, ret, blk_free_count; | |
382 | ext4_grpblk_t blocks_freed; | |
383 | struct ext4_group_info *grp; | |
384 | ||
385 | ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1); | |
386 | ||
387 | ext4_get_group_no_and_offset(sb, block, &block_group, &bit); | |
388 | grp = ext4_get_group_info(sb, block_group); | |
389 | /* | |
390 | * Check to see if we are freeing blocks across a group | |
391 | * boundary. | |
392 | */ | |
393 | if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) { | |
394 | goto error_return; | |
395 | } | |
396 | bitmap_bh = ext4_read_block_bitmap(sb, block_group); | |
397 | if (!bitmap_bh) | |
398 | goto error_return; | |
399 | desc = ext4_get_group_desc(sb, block_group, &gd_bh); | |
400 | if (!desc) | |
401 | goto error_return; | |
402 | ||
403 | if (in_range(ext4_block_bitmap(sb, desc), block, count) || | |
404 | in_range(ext4_inode_bitmap(sb, desc), block, count) || | |
405 | in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) || | |
406 | in_range(block + count - 1, ext4_inode_table(sb, desc), | |
407 | sbi->s_itb_per_group)) { | |
408 | ext4_error(sb, "Adding blocks in system zones - " | |
409 | "Block = %llu, count = %lu", | |
410 | block, count); | |
411 | goto error_return; | |
412 | } | |
413 | ||
414 | /* | |
415 | * We are about to add blocks to the bitmap, | |
416 | * so we need undo access. | |
417 | */ | |
418 | BUFFER_TRACE(bitmap_bh, "getting undo access"); | |
419 | err = ext4_journal_get_undo_access(handle, bitmap_bh); | |
420 | if (err) | |
421 | goto error_return; | |
422 | ||
423 | /* | |
424 | * We are about to modify some metadata. Call the journal APIs | |
425 | * to unshare ->b_data if a currently-committing transaction is | |
426 | * using it | |
427 | */ | |
428 | BUFFER_TRACE(gd_bh, "get_write_access"); | |
429 | err = ext4_journal_get_write_access(handle, gd_bh); | |
430 | if (err) | |
431 | goto error_return; | |
432 | /* | |
433 | * make sure we don't allow a parallel init on other groups in the | |
434 | * same buddy cache | |
435 | */ | |
436 | down_write(&grp->alloc_sem); | |
437 | for (i = 0, blocks_freed = 0; i < count; i++) { | |
438 | BUFFER_TRACE(bitmap_bh, "clear bit"); | |
439 | if (!ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group), | |
440 | bit + i, bitmap_bh->b_data)) { | |
441 | ext4_error(sb, "bit already cleared for block %llu", | |
442 | (ext4_fsblk_t)(block + i)); | |
443 | BUFFER_TRACE(bitmap_bh, "bit already cleared"); | |
444 | } else { | |
445 | blocks_freed++; | |
446 | } | |
447 | } | |
448 | ext4_lock_group(sb, block_group); | |
449 | blk_free_count = blocks_freed + ext4_free_blks_count(sb, desc); | |
450 | ext4_free_blks_set(sb, desc, blk_free_count); | |
451 | desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc); | |
452 | ext4_unlock_group(sb, block_group); | |
453 | percpu_counter_add(&sbi->s_freeblocks_counter, blocks_freed); | |
454 | ||
455 | if (sbi->s_log_groups_per_flex) { | |
456 | ext4_group_t flex_group = ext4_flex_group(sbi, block_group); | |
457 | atomic_add(blocks_freed, | |
458 | &sbi->s_flex_groups[flex_group].free_blocks); | |
459 | } | |
460 | /* | |
461 | * request to reload the buddy with the | |
462 | * new bitmap information | |
463 | */ | |
464 | set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state)); | |
465 | grp->bb_free += blocks_freed; | |
466 | up_write(&grp->alloc_sem); | |
467 | ||
468 | /* We dirtied the bitmap block */ | |
469 | BUFFER_TRACE(bitmap_bh, "dirtied bitmap block"); | |
470 | err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh); | |
471 | ||
472 | /* And the group descriptor block */ | |
473 | BUFFER_TRACE(gd_bh, "dirtied group descriptor block"); | |
474 | ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh); | |
475 | if (!err) | |
476 | err = ret; | |
477 | ||
478 | error_return: | |
479 | brelse(bitmap_bh); | |
480 | ext4_std_error(sb, err); | |
481 | return; | |
482 | } | |
483 | ||
484 | /** | |
485 | * ext4_has_free_blocks() | |
486 | * @sbi: in-core super block structure. | |
487 | * @nblocks: number of needed blocks | |
488 | * | |
489 | * Check if filesystem has nblocks free & available for allocation. | |
490 | * On success return 1, return 0 on failure. | |
491 | */ | |
492 | static int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks) | |
493 | { | |
494 | s64 free_blocks, dirty_blocks, root_blocks; | |
495 | struct percpu_counter *fbc = &sbi->s_freeblocks_counter; | |
496 | struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter; | |
497 | ||
498 | free_blocks = percpu_counter_read_positive(fbc); | |
499 | dirty_blocks = percpu_counter_read_positive(dbc); | |
500 | root_blocks = ext4_r_blocks_count(sbi->s_es); | |
501 | ||
502 | if (free_blocks - (nblocks + root_blocks + dirty_blocks) < | |
503 | EXT4_FREEBLOCKS_WATERMARK) { | |
504 | free_blocks = percpu_counter_sum_positive(fbc); | |
505 | dirty_blocks = percpu_counter_sum_positive(dbc); | |
506 | if (dirty_blocks < 0) { | |
507 | printk(KERN_CRIT "Dirty block accounting " | |
508 | "went wrong %lld\n", | |
509 | (long long)dirty_blocks); | |
510 | } | |
511 | } | |
512 | /* Check whether we have space after | |
513 | * accounting for current dirty blocks & root reserved blocks. | |
514 | */ | |
515 | if (free_blocks >= ((root_blocks + nblocks) + dirty_blocks)) | |
516 | return 1; | |
517 | ||
518 | /* Hm, nope. Are (enough) root reserved blocks available? */ | |
519 | if (sbi->s_resuid == current_fsuid() || | |
520 | ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) || | |
521 | capable(CAP_SYS_RESOURCE)) { | |
522 | if (free_blocks >= (nblocks + dirty_blocks)) | |
523 | return 1; | |
524 | } | |
525 | ||
526 | return 0; | |
527 | } | |
528 | ||
529 | int ext4_claim_free_blocks(struct ext4_sb_info *sbi, | |
530 | s64 nblocks) | |
531 | { | |
532 | if (ext4_has_free_blocks(sbi, nblocks)) { | |
533 | percpu_counter_add(&sbi->s_dirtyblocks_counter, nblocks); | |
534 | return 0; | |
535 | } else | |
536 | return -ENOSPC; | |
537 | } | |
538 | ||
539 | /** | |
540 | * ext4_should_retry_alloc() | |
541 | * @sb: super block | |
542 | * @retries number of attemps has been made | |
543 | * | |
544 | * ext4_should_retry_alloc() is called when ENOSPC is returned, and if | |
545 | * it is profitable to retry the operation, this function will wait | |
546 | * for the current or commiting transaction to complete, and then | |
547 | * return TRUE. | |
548 | * | |
549 | * if the total number of retries exceed three times, return FALSE. | |
550 | */ | |
551 | int ext4_should_retry_alloc(struct super_block *sb, int *retries) | |
552 | { | |
553 | if (!ext4_has_free_blocks(EXT4_SB(sb), 1) || | |
554 | (*retries)++ > 3 || | |
555 | !EXT4_SB(sb)->s_journal) | |
556 | return 0; | |
557 | ||
558 | jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); | |
559 | ||
560 | return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); | |
561 | } | |
562 | ||
563 | /* | |
564 | * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks | |
565 | * | |
566 | * @handle: handle to this transaction | |
567 | * @inode: file inode | |
568 | * @goal: given target block(filesystem wide) | |
569 | * @count: pointer to total number of blocks needed | |
570 | * @errp: error code | |
571 | * | |
572 | * Return 1st allocated block number on success, *count stores total account | |
573 | * error stores in errp pointer | |
574 | */ | |
575 | ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, | |
576 | ext4_fsblk_t goal, unsigned long *count, int *errp) | |
577 | { | |
578 | struct ext4_allocation_request ar; | |
579 | ext4_fsblk_t ret; | |
580 | ||
581 | memset(&ar, 0, sizeof(ar)); | |
582 | /* Fill with neighbour allocated blocks */ | |
583 | ar.inode = inode; | |
584 | ar.goal = goal; | |
585 | ar.len = count ? *count : 1; | |
586 | ||
587 | ret = ext4_mb_new_blocks(handle, &ar, errp); | |
588 | if (count) | |
589 | *count = ar.len; | |
590 | /* | |
591 | * Account for the allocated meta blocks. We will never | |
592 | * fail EDQUOT for metdata, but we do account for it. | |
593 | */ | |
594 | if (!(*errp) && EXT4_I(inode)->i_delalloc_reserved_flag) { | |
595 | spin_lock(&EXT4_I(inode)->i_block_reservation_lock); | |
596 | EXT4_I(inode)->i_allocated_meta_blocks += ar.len; | |
597 | spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); | |
598 | dquot_alloc_block_nofail(inode, ar.len); | |
599 | } | |
600 | return ret; | |
601 | } | |
602 | ||
603 | /** | |
604 | * ext4_count_free_blocks() -- count filesystem free blocks | |
605 | * @sb: superblock | |
606 | * | |
607 | * Adds up the number of free blocks from each block group. | |
608 | */ | |
609 | ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb) | |
610 | { | |
611 | ext4_fsblk_t desc_count; | |
612 | struct ext4_group_desc *gdp; | |
613 | ext4_group_t i; | |
614 | ext4_group_t ngroups = ext4_get_groups_count(sb); | |
615 | #ifdef EXT4FS_DEBUG | |
616 | struct ext4_super_block *es; | |
617 | ext4_fsblk_t bitmap_count; | |
618 | unsigned int x; | |
619 | struct buffer_head *bitmap_bh = NULL; | |
620 | ||
621 | es = EXT4_SB(sb)->s_es; | |
622 | desc_count = 0; | |
623 | bitmap_count = 0; | |
624 | gdp = NULL; | |
625 | ||
626 | for (i = 0; i < ngroups; i++) { | |
627 | gdp = ext4_get_group_desc(sb, i, NULL); | |
628 | if (!gdp) | |
629 | continue; | |
630 | desc_count += ext4_free_blks_count(sb, gdp); | |
631 | brelse(bitmap_bh); | |
632 | bitmap_bh = ext4_read_block_bitmap(sb, i); | |
633 | if (bitmap_bh == NULL) | |
634 | continue; | |
635 | ||
636 | x = ext4_count_free(bitmap_bh, sb->s_blocksize); | |
637 | printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", | |
638 | i, ext4_free_blks_count(sb, gdp), x); | |
639 | bitmap_count += x; | |
640 | } | |
641 | brelse(bitmap_bh); | |
642 | printk(KERN_DEBUG "ext4_count_free_blocks: stored = %llu" | |
643 | ", computed = %llu, %llu\n", ext4_free_blocks_count(es), | |
644 | desc_count, bitmap_count); | |
645 | return bitmap_count; | |
646 | #else | |
647 | desc_count = 0; | |
648 | for (i = 0; i < ngroups; i++) { | |
649 | gdp = ext4_get_group_desc(sb, i, NULL); | |
650 | if (!gdp) | |
651 | continue; | |
652 | desc_count += ext4_free_blks_count(sb, gdp); | |
653 | } | |
654 | ||
655 | return desc_count; | |
656 | #endif | |
657 | } | |
658 | ||
659 | static inline int test_root(ext4_group_t a, int b) | |
660 | { | |
661 | int num = b; | |
662 | ||
663 | while (a > num) | |
664 | num *= b; | |
665 | return num == a; | |
666 | } | |
667 | ||
668 | static int ext4_group_sparse(ext4_group_t group) | |
669 | { | |
670 | if (group <= 1) | |
671 | return 1; | |
672 | if (!(group & 1)) | |
673 | return 0; | |
674 | return (test_root(group, 7) || test_root(group, 5) || | |
675 | test_root(group, 3)); | |
676 | } | |
677 | ||
678 | /** | |
679 | * ext4_bg_has_super - number of blocks used by the superblock in group | |
680 | * @sb: superblock for filesystem | |
681 | * @group: group number to check | |
682 | * | |
683 | * Return the number of blocks used by the superblock (primary or backup) | |
684 | * in this group. Currently this will be only 0 or 1. | |
685 | */ | |
686 | int ext4_bg_has_super(struct super_block *sb, ext4_group_t group) | |
687 | { | |
688 | if (EXT4_HAS_RO_COMPAT_FEATURE(sb, | |
689 | EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && | |
690 | !ext4_group_sparse(group)) | |
691 | return 0; | |
692 | return 1; | |
693 | } | |
694 | ||
695 | static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, | |
696 | ext4_group_t group) | |
697 | { | |
698 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
699 | ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); | |
700 | ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; | |
701 | ||
702 | if (group == first || group == first + 1 || group == last) | |
703 | return 1; | |
704 | return 0; | |
705 | } | |
706 | ||
707 | static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, | |
708 | ext4_group_t group) | |
709 | { | |
710 | if (!ext4_bg_has_super(sb, group)) | |
711 | return 0; | |
712 | ||
713 | if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG)) | |
714 | return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); | |
715 | else | |
716 | return EXT4_SB(sb)->s_gdb_count; | |
717 | } | |
718 | ||
719 | /** | |
720 | * ext4_bg_num_gdb - number of blocks used by the group table in group | |
721 | * @sb: superblock for filesystem | |
722 | * @group: group number to check | |
723 | * | |
724 | * Return the number of blocks used by the group descriptor table | |
725 | * (primary or backup) in this group. In the future there may be a | |
726 | * different number of descriptor blocks in each group. | |
727 | */ | |
728 | unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) | |
729 | { | |
730 | unsigned long first_meta_bg = | |
731 | le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); | |
732 | unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); | |
733 | ||
734 | if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) || | |
735 | metagroup < first_meta_bg) | |
736 | return ext4_bg_num_gdb_nometa(sb, group); | |
737 | ||
738 | return ext4_bg_num_gdb_meta(sb,group); | |
739 | ||
740 | } | |
741 |