Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/ext2/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 | ||
1da177e4 LT |
14 | #include "ext2.h" |
15 | #include <linux/quotaops.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/buffer_head.h> | |
16f7e0fe | 18 | #include <linux/capability.h> |
1da177e4 LT |
19 | |
20 | /* | |
21 | * balloc.c contains the blocks allocation and deallocation routines | |
22 | */ | |
23 | ||
24 | /* | |
25 | * The free blocks are managed by bitmaps. A file system contains several | |
26 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
27 | * block for inodes, N blocks for the inode table and data blocks. | |
28 | * | |
29 | * The file system contains group descriptors which are located after the | |
30 | * super block. Each descriptor contains the number of the bitmap block and | |
31 | * the free blocks count in the block. The descriptors are loaded in memory | |
e627432c | 32 | * when a file system is mounted (see ext2_fill_super). |
1da177e4 LT |
33 | */ |
34 | ||
35 | ||
36 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
37 | ||
38 | struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb, | |
39 | unsigned int block_group, | |
40 | struct buffer_head ** bh) | |
41 | { | |
42 | unsigned long group_desc; | |
43 | unsigned long offset; | |
44 | struct ext2_group_desc * desc; | |
45 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
46 | ||
47 | if (block_group >= sbi->s_groups_count) { | |
48 | ext2_error (sb, "ext2_get_group_desc", | |
49 | "block_group >= groups_count - " | |
50 | "block_group = %d, groups_count = %lu", | |
51 | block_group, sbi->s_groups_count); | |
52 | ||
53 | return NULL; | |
54 | } | |
55 | ||
56 | group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb); | |
57 | offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1); | |
58 | if (!sbi->s_group_desc[group_desc]) { | |
59 | ext2_error (sb, "ext2_get_group_desc", | |
60 | "Group descriptor not loaded - " | |
61 | "block_group = %d, group_desc = %lu, desc = %lu", | |
62 | block_group, group_desc, offset); | |
63 | return NULL; | |
64 | } | |
65 | ||
66 | desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data; | |
67 | if (bh) | |
68 | *bh = sbi->s_group_desc[group_desc]; | |
69 | return desc + offset; | |
70 | } | |
71 | ||
7c9e69fa AK |
72 | static inline int |
73 | block_in_use(unsigned long block, struct super_block *sb, unsigned char *map) | |
74 | { | |
75 | return ext2_test_bit ((block - | |
76 | le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) % | |
77 | EXT2_BLOCKS_PER_GROUP(sb), map); | |
78 | } | |
79 | ||
1da177e4 LT |
80 | /* |
81 | * Read the bitmap for a given block_group, reading into the specified | |
82 | * slot in the superblock's bitmap cache. | |
83 | * | |
84 | * Return buffer_head on success or NULL in case of failure. | |
85 | */ | |
86 | static struct buffer_head * | |
87 | read_block_bitmap(struct super_block *sb, unsigned int block_group) | |
88 | { | |
7c9e69fa | 89 | int i; |
1da177e4 LT |
90 | struct ext2_group_desc * desc; |
91 | struct buffer_head * bh = NULL; | |
7c9e69fa AK |
92 | unsigned int bitmap_blk; |
93 | ||
1da177e4 LT |
94 | desc = ext2_get_group_desc (sb, block_group, NULL); |
95 | if (!desc) | |
7c9e69fa AK |
96 | return NULL; |
97 | bitmap_blk = le32_to_cpu(desc->bg_block_bitmap); | |
98 | bh = sb_bread(sb, bitmap_blk); | |
1da177e4 | 99 | if (!bh) |
7c9e69fa | 100 | ext2_error (sb, __FUNCTION__, |
1da177e4 LT |
101 | "Cannot read block bitmap - " |
102 | "block_group = %d, block_bitmap = %u", | |
103 | block_group, le32_to_cpu(desc->bg_block_bitmap)); | |
7c9e69fa AK |
104 | |
105 | /* check whether block bitmap block number is set */ | |
106 | if (!block_in_use(bitmap_blk, sb, bh->b_data)) { | |
107 | /* bad block bitmap */ | |
108 | goto error_out; | |
109 | } | |
110 | /* check whether the inode bitmap block number is set */ | |
111 | bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap); | |
112 | if (!block_in_use(bitmap_blk, sb, bh->b_data)) { | |
113 | /* bad block bitmap */ | |
114 | goto error_out; | |
115 | } | |
116 | /* check whether the inode table block number is set */ | |
117 | bitmap_blk = le32_to_cpu(desc->bg_inode_table); | |
118 | for (i = 0; i < EXT2_SB(sb)->s_itb_per_group; i++, bitmap_blk++) { | |
119 | if (!block_in_use(bitmap_blk, sb, bh->b_data)) { | |
120 | /* bad block bitmap */ | |
121 | goto error_out; | |
122 | } | |
123 | } | |
124 | ||
1da177e4 | 125 | return bh; |
7c9e69fa AK |
126 | |
127 | error_out: | |
128 | brelse(bh); | |
129 | ext2_error(sb, __FUNCTION__, | |
130 | "Invalid block bitmap - " | |
131 | "block_group = %d, block = %u", | |
132 | block_group, bitmap_blk); | |
133 | return NULL; | |
1da177e4 LT |
134 | } |
135 | ||
136 | /* | |
137 | * Set sb->s_dirt here because the superblock was "logically" altered. We | |
138 | * need to recalculate its free blocks count and flush it out. | |
139 | */ | |
140 | static int reserve_blocks(struct super_block *sb, int count) | |
141 | { | |
142 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
143 | struct ext2_super_block *es = sbi->s_es; | |
144 | unsigned free_blocks; | |
145 | unsigned root_blocks; | |
146 | ||
147 | free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); | |
148 | root_blocks = le32_to_cpu(es->s_r_blocks_count); | |
149 | ||
150 | if (free_blocks < count) | |
151 | count = free_blocks; | |
152 | ||
153 | if (free_blocks < root_blocks + count && !capable(CAP_SYS_RESOURCE) && | |
154 | sbi->s_resuid != current->fsuid && | |
155 | (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { | |
156 | /* | |
157 | * We are too close to reserve and we are not privileged. | |
158 | * Can we allocate anything at all? | |
159 | */ | |
160 | if (free_blocks > root_blocks) | |
161 | count = free_blocks - root_blocks; | |
162 | else | |
163 | return 0; | |
164 | } | |
165 | ||
3cb4f9fa | 166 | percpu_counter_sub(&sbi->s_freeblocks_counter, count); |
1da177e4 LT |
167 | sb->s_dirt = 1; |
168 | return count; | |
169 | } | |
170 | ||
171 | static void release_blocks(struct super_block *sb, int count) | |
172 | { | |
173 | if (count) { | |
174 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
175 | ||
aa0dff2d | 176 | percpu_counter_add(&sbi->s_freeblocks_counter, count); |
1da177e4 LT |
177 | sb->s_dirt = 1; |
178 | } | |
179 | } | |
180 | ||
181 | static int group_reserve_blocks(struct ext2_sb_info *sbi, int group_no, | |
182 | struct ext2_group_desc *desc, struct buffer_head *bh, int count) | |
183 | { | |
184 | unsigned free_blocks; | |
185 | ||
186 | if (!desc->bg_free_blocks_count) | |
187 | return 0; | |
188 | ||
189 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
190 | free_blocks = le16_to_cpu(desc->bg_free_blocks_count); | |
191 | if (free_blocks < count) | |
192 | count = free_blocks; | |
193 | desc->bg_free_blocks_count = cpu_to_le16(free_blocks - count); | |
194 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
195 | mark_buffer_dirty(bh); | |
196 | return count; | |
197 | } | |
198 | ||
199 | static void group_release_blocks(struct super_block *sb, int group_no, | |
200 | struct ext2_group_desc *desc, struct buffer_head *bh, int count) | |
201 | { | |
202 | if (count) { | |
203 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
204 | unsigned free_blocks; | |
205 | ||
206 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
207 | free_blocks = le16_to_cpu(desc->bg_free_blocks_count); | |
208 | desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count); | |
209 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
210 | sb->s_dirt = 1; | |
211 | mark_buffer_dirty(bh); | |
212 | } | |
213 | } | |
214 | ||
215 | /* Free given blocks, update quota and i_blocks field */ | |
216 | void ext2_free_blocks (struct inode * inode, unsigned long block, | |
217 | unsigned long count) | |
218 | { | |
219 | struct buffer_head *bitmap_bh = NULL; | |
220 | struct buffer_head * bh2; | |
221 | unsigned long block_group; | |
222 | unsigned long bit; | |
223 | unsigned long i; | |
224 | unsigned long overflow; | |
225 | struct super_block * sb = inode->i_sb; | |
226 | struct ext2_sb_info * sbi = EXT2_SB(sb); | |
227 | struct ext2_group_desc * desc; | |
228 | struct ext2_super_block * es = sbi->s_es; | |
229 | unsigned freed = 0, group_freed; | |
230 | ||
231 | if (block < le32_to_cpu(es->s_first_data_block) || | |
232 | block + count < block || | |
233 | block + count > le32_to_cpu(es->s_blocks_count)) { | |
234 | ext2_error (sb, "ext2_free_blocks", | |
235 | "Freeing blocks not in datazone - " | |
236 | "block = %lu, count = %lu", block, count); | |
237 | goto error_return; | |
238 | } | |
239 | ||
240 | ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); | |
241 | ||
242 | do_more: | |
243 | overflow = 0; | |
244 | block_group = (block - le32_to_cpu(es->s_first_data_block)) / | |
245 | EXT2_BLOCKS_PER_GROUP(sb); | |
246 | bit = (block - le32_to_cpu(es->s_first_data_block)) % | |
247 | EXT2_BLOCKS_PER_GROUP(sb); | |
248 | /* | |
249 | * Check to see if we are freeing blocks across a group | |
250 | * boundary. | |
251 | */ | |
252 | if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) { | |
253 | overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb); | |
254 | count -= overflow; | |
255 | } | |
256 | brelse(bitmap_bh); | |
257 | bitmap_bh = read_block_bitmap(sb, block_group); | |
258 | if (!bitmap_bh) | |
259 | goto error_return; | |
260 | ||
261 | desc = ext2_get_group_desc (sb, block_group, &bh2); | |
262 | if (!desc) | |
263 | goto error_return; | |
264 | ||
265 | if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || | |
266 | in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || | |
267 | in_range (block, le32_to_cpu(desc->bg_inode_table), | |
268 | sbi->s_itb_per_group) || | |
269 | in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), | |
270 | sbi->s_itb_per_group)) | |
271 | ext2_error (sb, "ext2_free_blocks", | |
272 | "Freeing blocks in system zones - " | |
273 | "Block = %lu, count = %lu", | |
274 | block, count); | |
275 | ||
276 | for (i = 0, group_freed = 0; i < count; i++) { | |
277 | if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group), | |
278 | bit + i, bitmap_bh->b_data)) { | |
279 | ext2_error(sb, __FUNCTION__, | |
280 | "bit already cleared for block %lu", block + i); | |
281 | } else { | |
282 | group_freed++; | |
283 | } | |
284 | } | |
285 | ||
286 | mark_buffer_dirty(bitmap_bh); | |
287 | if (sb->s_flags & MS_SYNCHRONOUS) | |
288 | sync_dirty_buffer(bitmap_bh); | |
289 | ||
290 | group_release_blocks(sb, block_group, desc, bh2, group_freed); | |
291 | freed += group_freed; | |
292 | ||
293 | if (overflow) { | |
294 | block += count; | |
295 | count = overflow; | |
296 | goto do_more; | |
297 | } | |
298 | error_return: | |
299 | brelse(bitmap_bh); | |
300 | release_blocks(sb, freed); | |
301 | DQUOT_FREE_BLOCK(inode, freed); | |
302 | } | |
303 | ||
304 | static int grab_block(spinlock_t *lock, char *map, unsigned size, int goal) | |
305 | { | |
306 | int k; | |
307 | char *p, *r; | |
308 | ||
309 | if (!ext2_test_bit(goal, map)) | |
310 | goto got_it; | |
311 | ||
312 | repeat: | |
313 | if (goal) { | |
314 | /* | |
315 | * The goal was occupied; search forward for a free | |
316 | * block within the next XX blocks. | |
317 | * | |
318 | * end_goal is more or less random, but it has to be | |
319 | * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the | |
320 | * next 64-bit boundary is simple.. | |
321 | */ | |
322 | k = (goal + 63) & ~63; | |
323 | goal = ext2_find_next_zero_bit(map, k, goal); | |
324 | if (goal < k) | |
325 | goto got_it; | |
326 | /* | |
327 | * Search in the remainder of the current group. | |
328 | */ | |
329 | } | |
330 | ||
331 | p = map + (goal >> 3); | |
332 | r = memscan(p, 0, (size - goal + 7) >> 3); | |
333 | k = (r - map) << 3; | |
334 | if (k < size) { | |
335 | /* | |
336 | * We have succeeded in finding a free byte in the block | |
337 | * bitmap. Now search backwards to find the start of this | |
338 | * group of free blocks - won't take more than 7 iterations. | |
339 | */ | |
340 | for (goal = k; goal && !ext2_test_bit (goal - 1, map); goal--) | |
341 | ; | |
342 | goto got_it; | |
343 | } | |
344 | ||
345 | k = ext2_find_next_zero_bit ((u32 *)map, size, goal); | |
346 | if (k < size) { | |
347 | goal = k; | |
348 | goto got_it; | |
349 | } | |
350 | return -1; | |
351 | got_it: | |
352 | if (ext2_set_bit_atomic(lock, goal, (void *) map)) | |
353 | goto repeat; | |
354 | return goal; | |
355 | } | |
356 | ||
357 | /* | |
358 | * ext2_new_block uses a goal block to assist allocation. If the goal is | |
359 | * free, or there is a free block within 32 blocks of the goal, that block | |
360 | * is allocated. Otherwise a forward search is made for a free block; within | |
361 | * each block group the search first looks for an entire free byte in the block | |
362 | * bitmap, and then for any free bit if that fails. | |
363 | * This function also updates quota and i_blocks field. | |
364 | */ | |
365 | int ext2_new_block(struct inode *inode, unsigned long goal, | |
366 | u32 *prealloc_count, u32 *prealloc_block, int *err) | |
367 | { | |
368 | struct buffer_head *bitmap_bh = NULL; | |
369 | struct buffer_head *gdp_bh; /* bh2 */ | |
370 | struct ext2_group_desc *desc; | |
371 | int group_no; /* i */ | |
372 | int ret_block; /* j */ | |
373 | int group_idx; /* k */ | |
374 | int target_block; /* tmp */ | |
375 | int block = 0; | |
376 | struct super_block *sb = inode->i_sb; | |
377 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
378 | struct ext2_super_block *es = sbi->s_es; | |
379 | unsigned group_size = EXT2_BLOCKS_PER_GROUP(sb); | |
380 | unsigned prealloc_goal = es->s_prealloc_blocks; | |
381 | unsigned group_alloc = 0, es_alloc, dq_alloc; | |
382 | int nr_scanned_groups; | |
383 | ||
384 | if (!prealloc_goal--) | |
385 | prealloc_goal = EXT2_DEFAULT_PREALLOC_BLOCKS - 1; | |
386 | if (!prealloc_count || *prealloc_count) | |
387 | prealloc_goal = 0; | |
388 | ||
389 | if (DQUOT_ALLOC_BLOCK(inode, 1)) { | |
390 | *err = -EDQUOT; | |
391 | goto out; | |
392 | } | |
393 | ||
394 | while (prealloc_goal && DQUOT_PREALLOC_BLOCK(inode, prealloc_goal)) | |
395 | prealloc_goal--; | |
396 | ||
397 | dq_alloc = prealloc_goal + 1; | |
398 | es_alloc = reserve_blocks(sb, dq_alloc); | |
399 | if (!es_alloc) { | |
400 | *err = -ENOSPC; | |
401 | goto out_dquot; | |
402 | } | |
403 | ||
404 | ext2_debug ("goal=%lu.\n", goal); | |
405 | ||
406 | if (goal < le32_to_cpu(es->s_first_data_block) || | |
407 | goal >= le32_to_cpu(es->s_blocks_count)) | |
408 | goal = le32_to_cpu(es->s_first_data_block); | |
409 | group_no = (goal - le32_to_cpu(es->s_first_data_block)) / group_size; | |
410 | desc = ext2_get_group_desc (sb, group_no, &gdp_bh); | |
411 | if (!desc) { | |
412 | /* | |
413 | * gdp_bh may still be uninitialised. But group_release_blocks | |
414 | * will not touch it because group_alloc is zero. | |
415 | */ | |
416 | goto io_error; | |
417 | } | |
418 | ||
419 | group_alloc = group_reserve_blocks(sbi, group_no, desc, | |
420 | gdp_bh, es_alloc); | |
421 | if (group_alloc) { | |
422 | ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) % | |
423 | group_size); | |
424 | brelse(bitmap_bh); | |
425 | bitmap_bh = read_block_bitmap(sb, group_no); | |
426 | if (!bitmap_bh) | |
427 | goto io_error; | |
428 | ||
429 | ext2_debug("goal is at %d:%d.\n", group_no, ret_block); | |
430 | ||
431 | ret_block = grab_block(sb_bgl_lock(sbi, group_no), | |
432 | bitmap_bh->b_data, group_size, ret_block); | |
433 | if (ret_block >= 0) | |
434 | goto got_block; | |
435 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
436 | group_alloc = 0; | |
437 | } | |
438 | ||
439 | ext2_debug ("Bit not found in block group %d.\n", group_no); | |
440 | ||
441 | /* | |
442 | * Now search the rest of the groups. We assume that | |
443 | * i and desc correctly point to the last group visited. | |
444 | */ | |
445 | nr_scanned_groups = 0; | |
446 | retry: | |
447 | for (group_idx = 0; !group_alloc && | |
448 | group_idx < sbi->s_groups_count; group_idx++) { | |
449 | group_no++; | |
450 | if (group_no >= sbi->s_groups_count) | |
451 | group_no = 0; | |
452 | desc = ext2_get_group_desc(sb, group_no, &gdp_bh); | |
453 | if (!desc) | |
454 | goto io_error; | |
455 | group_alloc = group_reserve_blocks(sbi, group_no, desc, | |
456 | gdp_bh, es_alloc); | |
457 | } | |
458 | if (!group_alloc) { | |
459 | *err = -ENOSPC; | |
460 | goto out_release; | |
461 | } | |
462 | brelse(bitmap_bh); | |
463 | bitmap_bh = read_block_bitmap(sb, group_no); | |
464 | if (!bitmap_bh) | |
465 | goto io_error; | |
466 | ||
467 | ret_block = grab_block(sb_bgl_lock(sbi, group_no), bitmap_bh->b_data, | |
468 | group_size, 0); | |
469 | if (ret_block < 0) { | |
470 | /* | |
471 | * If a free block counter is corrupted we can loop inifintely. | |
472 | * Detect that here. | |
473 | */ | |
474 | nr_scanned_groups++; | |
475 | if (nr_scanned_groups > 2 * sbi->s_groups_count) { | |
476 | ext2_error(sb, "ext2_new_block", | |
477 | "corrupted free blocks counters"); | |
478 | goto io_error; | |
479 | } | |
480 | /* | |
481 | * Someone else grabbed the last free block in this blockgroup | |
482 | * before us. Retry the scan. | |
483 | */ | |
484 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
485 | group_alloc = 0; | |
486 | goto retry; | |
487 | } | |
488 | ||
489 | got_block: | |
490 | ext2_debug("using block group %d(%d)\n", | |
491 | group_no, desc->bg_free_blocks_count); | |
492 | ||
493 | target_block = ret_block + group_no * group_size + | |
494 | le32_to_cpu(es->s_first_data_block); | |
495 | ||
496 | if (target_block == le32_to_cpu(desc->bg_block_bitmap) || | |
497 | target_block == le32_to_cpu(desc->bg_inode_bitmap) || | |
498 | in_range(target_block, le32_to_cpu(desc->bg_inode_table), | |
499 | sbi->s_itb_per_group)) | |
500 | ext2_error (sb, "ext2_new_block", | |
501 | "Allocating block in system zone - " | |
502 | "block = %u", target_block); | |
503 | ||
504 | if (target_block >= le32_to_cpu(es->s_blocks_count)) { | |
505 | ext2_error (sb, "ext2_new_block", | |
506 | "block(%d) >= blocks count(%d) - " | |
507 | "block_group = %d, es == %p ", ret_block, | |
508 | le32_to_cpu(es->s_blocks_count), group_no, es); | |
509 | goto io_error; | |
510 | } | |
511 | block = target_block; | |
512 | ||
513 | /* OK, we _had_ allocated something */ | |
514 | ext2_debug("found bit %d\n", ret_block); | |
515 | ||
516 | dq_alloc--; | |
517 | es_alloc--; | |
518 | group_alloc--; | |
519 | ||
520 | /* | |
521 | * Do block preallocation now if required. | |
522 | */ | |
523 | write_lock(&EXT2_I(inode)->i_meta_lock); | |
524 | if (group_alloc && !*prealloc_count) { | |
525 | unsigned n; | |
526 | ||
527 | for (n = 0; n < group_alloc && ++ret_block < group_size; n++) { | |
528 | if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group_no), | |
529 | ret_block, | |
530 | (void*) bitmap_bh->b_data)) | |
531 | break; | |
532 | } | |
533 | *prealloc_block = block + 1; | |
534 | *prealloc_count = n; | |
535 | es_alloc -= n; | |
536 | dq_alloc -= n; | |
537 | group_alloc -= n; | |
538 | } | |
539 | write_unlock(&EXT2_I(inode)->i_meta_lock); | |
540 | ||
541 | mark_buffer_dirty(bitmap_bh); | |
542 | if (sb->s_flags & MS_SYNCHRONOUS) | |
543 | sync_dirty_buffer(bitmap_bh); | |
544 | ||
545 | ext2_debug ("allocating block %d. ", block); | |
546 | ||
547 | *err = 0; | |
548 | out_release: | |
549 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
550 | release_blocks(sb, es_alloc); | |
551 | out_dquot: | |
552 | DQUOT_FREE_BLOCK(inode, dq_alloc); | |
553 | out: | |
554 | brelse(bitmap_bh); | |
555 | return block; | |
556 | ||
557 | io_error: | |
558 | *err = -EIO; | |
559 | goto out_release; | |
560 | } | |
561 | ||
21730eed VH |
562 | #ifdef EXT2FS_DEBUG |
563 | ||
febfcf91 | 564 | static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0}; |
21730eed VH |
565 | |
566 | unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars) | |
567 | { | |
568 | unsigned int i; | |
569 | unsigned long sum = 0; | |
570 | ||
571 | if (!map) | |
572 | return (0); | |
573 | for (i = 0; i < numchars; i++) | |
574 | sum += nibblemap[map->b_data[i] & 0xf] + | |
575 | nibblemap[(map->b_data[i] >> 4) & 0xf]; | |
576 | return (sum); | |
577 | } | |
578 | ||
579 | #endif /* EXT2FS_DEBUG */ | |
580 | ||
1da177e4 LT |
581 | unsigned long ext2_count_free_blocks (struct super_block * sb) |
582 | { | |
583 | struct ext2_group_desc * desc; | |
584 | unsigned long desc_count = 0; | |
585 | int i; | |
586 | #ifdef EXT2FS_DEBUG | |
587 | unsigned long bitmap_count, x; | |
588 | struct ext2_super_block *es; | |
589 | ||
1da177e4 LT |
590 | es = EXT2_SB(sb)->s_es; |
591 | desc_count = 0; | |
592 | bitmap_count = 0; | |
593 | desc = NULL; | |
594 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
595 | struct buffer_head *bitmap_bh; | |
596 | desc = ext2_get_group_desc (sb, i, NULL); | |
597 | if (!desc) | |
598 | continue; | |
599 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
600 | bitmap_bh = read_block_bitmap(sb, i); | |
601 | if (!bitmap_bh) | |
602 | continue; | |
603 | ||
604 | x = ext2_count_free(bitmap_bh, sb->s_blocksize); | |
605 | printk ("group %d: stored = %d, counted = %lu\n", | |
606 | i, le16_to_cpu(desc->bg_free_blocks_count), x); | |
607 | bitmap_count += x; | |
608 | brelse(bitmap_bh); | |
609 | } | |
610 | printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n", | |
611 | (long)le32_to_cpu(es->s_free_blocks_count), | |
612 | desc_count, bitmap_count); | |
1da177e4 LT |
613 | return bitmap_count; |
614 | #else | |
615 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
616 | desc = ext2_get_group_desc (sb, i, NULL); | |
617 | if (!desc) | |
618 | continue; | |
619 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
620 | } | |
621 | return desc_count; | |
622 | #endif | |
623 | } | |
624 | ||
1da177e4 LT |
625 | |
626 | static inline int test_root(int a, int b) | |
627 | { | |
628 | int num = b; | |
629 | ||
630 | while (a > num) | |
631 | num *= b; | |
632 | return num == a; | |
633 | } | |
634 | ||
635 | static int ext2_group_sparse(int group) | |
636 | { | |
637 | if (group <= 1) | |
638 | return 1; | |
639 | return (test_root(group, 3) || test_root(group, 5) || | |
640 | test_root(group, 7)); | |
641 | } | |
642 | ||
643 | /** | |
644 | * ext2_bg_has_super - number of blocks used by the superblock in group | |
645 | * @sb: superblock for filesystem | |
646 | * @group: group number to check | |
647 | * | |
648 | * Return the number of blocks used by the superblock (primary or backup) | |
649 | * in this group. Currently this will be only 0 or 1. | |
650 | */ | |
651 | int ext2_bg_has_super(struct super_block *sb, int group) | |
652 | { | |
653 | if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& | |
654 | !ext2_group_sparse(group)) | |
655 | return 0; | |
656 | return 1; | |
657 | } | |
658 | ||
659 | /** | |
660 | * ext2_bg_num_gdb - number of blocks used by the group table in group | |
661 | * @sb: superblock for filesystem | |
662 | * @group: group number to check | |
663 | * | |
664 | * Return the number of blocks used by the group descriptor table | |
665 | * (primary or backup) in this group. In the future there may be a | |
666 | * different number of descriptor blocks in each group. | |
667 | */ | |
668 | unsigned long ext2_bg_num_gdb(struct super_block *sb, int group) | |
669 | { | |
670 | if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& | |
671 | !ext2_group_sparse(group)) | |
672 | return 0; | |
673 | return EXT2_SB(sb)->s_gdb_count; | |
674 | } | |
675 |