]>
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 | ||
14 | #include <linux/config.h> | |
15 | #include "ext2.h" | |
16 | #include <linux/quotaops.h> | |
17 | #include <linux/sched.h> | |
18 | #include <linux/buffer_head.h> | |
16f7e0fe | 19 | #include <linux/capability.h> |
1da177e4 LT |
20 | |
21 | /* | |
22 | * balloc.c contains the blocks allocation and deallocation routines | |
23 | */ | |
24 | ||
25 | /* | |
26 | * The free blocks are managed by bitmaps. A file system contains several | |
27 | * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap | |
28 | * block for inodes, N blocks for the inode table and data blocks. | |
29 | * | |
30 | * The file system contains group descriptors which are located after the | |
31 | * super block. Each descriptor contains the number of the bitmap block and | |
32 | * the free blocks count in the block. The descriptors are loaded in memory | |
33 | * when a file system is mounted (see ext2_read_super). | |
34 | */ | |
35 | ||
36 | ||
37 | #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) | |
38 | ||
39 | struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb, | |
40 | unsigned int block_group, | |
41 | struct buffer_head ** bh) | |
42 | { | |
43 | unsigned long group_desc; | |
44 | unsigned long offset; | |
45 | struct ext2_group_desc * desc; | |
46 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
47 | ||
48 | if (block_group >= sbi->s_groups_count) { | |
49 | ext2_error (sb, "ext2_get_group_desc", | |
50 | "block_group >= groups_count - " | |
51 | "block_group = %d, groups_count = %lu", | |
52 | block_group, sbi->s_groups_count); | |
53 | ||
54 | return NULL; | |
55 | } | |
56 | ||
57 | group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb); | |
58 | offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1); | |
59 | if (!sbi->s_group_desc[group_desc]) { | |
60 | ext2_error (sb, "ext2_get_group_desc", | |
61 | "Group descriptor not loaded - " | |
62 | "block_group = %d, group_desc = %lu, desc = %lu", | |
63 | block_group, group_desc, offset); | |
64 | return NULL; | |
65 | } | |
66 | ||
67 | desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data; | |
68 | if (bh) | |
69 | *bh = sbi->s_group_desc[group_desc]; | |
70 | return desc + offset; | |
71 | } | |
72 | ||
73 | /* | |
74 | * Read the bitmap for a given block_group, reading into the specified | |
75 | * slot in the superblock's bitmap cache. | |
76 | * | |
77 | * Return buffer_head on success or NULL in case of failure. | |
78 | */ | |
79 | static struct buffer_head * | |
80 | read_block_bitmap(struct super_block *sb, unsigned int block_group) | |
81 | { | |
82 | struct ext2_group_desc * desc; | |
83 | struct buffer_head * bh = NULL; | |
84 | ||
85 | desc = ext2_get_group_desc (sb, block_group, NULL); | |
86 | if (!desc) | |
87 | goto error_out; | |
88 | bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap)); | |
89 | if (!bh) | |
90 | ext2_error (sb, "read_block_bitmap", | |
91 | "Cannot read block bitmap - " | |
92 | "block_group = %d, block_bitmap = %u", | |
93 | block_group, le32_to_cpu(desc->bg_block_bitmap)); | |
94 | error_out: | |
95 | return bh; | |
96 | } | |
97 | ||
98 | /* | |
99 | * Set sb->s_dirt here because the superblock was "logically" altered. We | |
100 | * need to recalculate its free blocks count and flush it out. | |
101 | */ | |
102 | static int reserve_blocks(struct super_block *sb, int count) | |
103 | { | |
104 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
105 | struct ext2_super_block *es = sbi->s_es; | |
106 | unsigned free_blocks; | |
107 | unsigned root_blocks; | |
108 | ||
109 | free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); | |
110 | root_blocks = le32_to_cpu(es->s_r_blocks_count); | |
111 | ||
112 | if (free_blocks < count) | |
113 | count = free_blocks; | |
114 | ||
115 | if (free_blocks < root_blocks + count && !capable(CAP_SYS_RESOURCE) && | |
116 | sbi->s_resuid != current->fsuid && | |
117 | (sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) { | |
118 | /* | |
119 | * We are too close to reserve and we are not privileged. | |
120 | * Can we allocate anything at all? | |
121 | */ | |
122 | if (free_blocks > root_blocks) | |
123 | count = free_blocks - root_blocks; | |
124 | else | |
125 | return 0; | |
126 | } | |
127 | ||
128 | percpu_counter_mod(&sbi->s_freeblocks_counter, -count); | |
129 | sb->s_dirt = 1; | |
130 | return count; | |
131 | } | |
132 | ||
133 | static void release_blocks(struct super_block *sb, int count) | |
134 | { | |
135 | if (count) { | |
136 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
137 | ||
138 | percpu_counter_mod(&sbi->s_freeblocks_counter, count); | |
139 | sb->s_dirt = 1; | |
140 | } | |
141 | } | |
142 | ||
143 | static int group_reserve_blocks(struct ext2_sb_info *sbi, int group_no, | |
144 | struct ext2_group_desc *desc, struct buffer_head *bh, int count) | |
145 | { | |
146 | unsigned free_blocks; | |
147 | ||
148 | if (!desc->bg_free_blocks_count) | |
149 | return 0; | |
150 | ||
151 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
152 | free_blocks = le16_to_cpu(desc->bg_free_blocks_count); | |
153 | if (free_blocks < count) | |
154 | count = free_blocks; | |
155 | desc->bg_free_blocks_count = cpu_to_le16(free_blocks - count); | |
156 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
157 | mark_buffer_dirty(bh); | |
158 | return count; | |
159 | } | |
160 | ||
161 | static void group_release_blocks(struct super_block *sb, int group_no, | |
162 | struct ext2_group_desc *desc, struct buffer_head *bh, int count) | |
163 | { | |
164 | if (count) { | |
165 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
166 | unsigned free_blocks; | |
167 | ||
168 | spin_lock(sb_bgl_lock(sbi, group_no)); | |
169 | free_blocks = le16_to_cpu(desc->bg_free_blocks_count); | |
170 | desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count); | |
171 | spin_unlock(sb_bgl_lock(sbi, group_no)); | |
172 | sb->s_dirt = 1; | |
173 | mark_buffer_dirty(bh); | |
174 | } | |
175 | } | |
176 | ||
177 | /* Free given blocks, update quota and i_blocks field */ | |
178 | void ext2_free_blocks (struct inode * inode, unsigned long block, | |
179 | unsigned long count) | |
180 | { | |
181 | struct buffer_head *bitmap_bh = NULL; | |
182 | struct buffer_head * bh2; | |
183 | unsigned long block_group; | |
184 | unsigned long bit; | |
185 | unsigned long i; | |
186 | unsigned long overflow; | |
187 | struct super_block * sb = inode->i_sb; | |
188 | struct ext2_sb_info * sbi = EXT2_SB(sb); | |
189 | struct ext2_group_desc * desc; | |
190 | struct ext2_super_block * es = sbi->s_es; | |
191 | unsigned freed = 0, group_freed; | |
192 | ||
193 | if (block < le32_to_cpu(es->s_first_data_block) || | |
194 | block + count < block || | |
195 | block + count > le32_to_cpu(es->s_blocks_count)) { | |
196 | ext2_error (sb, "ext2_free_blocks", | |
197 | "Freeing blocks not in datazone - " | |
198 | "block = %lu, count = %lu", block, count); | |
199 | goto error_return; | |
200 | } | |
201 | ||
202 | ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1); | |
203 | ||
204 | do_more: | |
205 | overflow = 0; | |
206 | block_group = (block - le32_to_cpu(es->s_first_data_block)) / | |
207 | EXT2_BLOCKS_PER_GROUP(sb); | |
208 | bit = (block - le32_to_cpu(es->s_first_data_block)) % | |
209 | EXT2_BLOCKS_PER_GROUP(sb); | |
210 | /* | |
211 | * Check to see if we are freeing blocks across a group | |
212 | * boundary. | |
213 | */ | |
214 | if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) { | |
215 | overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb); | |
216 | count -= overflow; | |
217 | } | |
218 | brelse(bitmap_bh); | |
219 | bitmap_bh = read_block_bitmap(sb, block_group); | |
220 | if (!bitmap_bh) | |
221 | goto error_return; | |
222 | ||
223 | desc = ext2_get_group_desc (sb, block_group, &bh2); | |
224 | if (!desc) | |
225 | goto error_return; | |
226 | ||
227 | if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) || | |
228 | in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) || | |
229 | in_range (block, le32_to_cpu(desc->bg_inode_table), | |
230 | sbi->s_itb_per_group) || | |
231 | in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table), | |
232 | sbi->s_itb_per_group)) | |
233 | ext2_error (sb, "ext2_free_blocks", | |
234 | "Freeing blocks in system zones - " | |
235 | "Block = %lu, count = %lu", | |
236 | block, count); | |
237 | ||
238 | for (i = 0, group_freed = 0; i < count; i++) { | |
239 | if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group), | |
240 | bit + i, bitmap_bh->b_data)) { | |
241 | ext2_error(sb, __FUNCTION__, | |
242 | "bit already cleared for block %lu", block + i); | |
243 | } else { | |
244 | group_freed++; | |
245 | } | |
246 | } | |
247 | ||
248 | mark_buffer_dirty(bitmap_bh); | |
249 | if (sb->s_flags & MS_SYNCHRONOUS) | |
250 | sync_dirty_buffer(bitmap_bh); | |
251 | ||
252 | group_release_blocks(sb, block_group, desc, bh2, group_freed); | |
253 | freed += group_freed; | |
254 | ||
255 | if (overflow) { | |
256 | block += count; | |
257 | count = overflow; | |
258 | goto do_more; | |
259 | } | |
260 | error_return: | |
261 | brelse(bitmap_bh); | |
262 | release_blocks(sb, freed); | |
263 | DQUOT_FREE_BLOCK(inode, freed); | |
264 | } | |
265 | ||
266 | static int grab_block(spinlock_t *lock, char *map, unsigned size, int goal) | |
267 | { | |
268 | int k; | |
269 | char *p, *r; | |
270 | ||
271 | if (!ext2_test_bit(goal, map)) | |
272 | goto got_it; | |
273 | ||
274 | repeat: | |
275 | if (goal) { | |
276 | /* | |
277 | * The goal was occupied; search forward for a free | |
278 | * block within the next XX blocks. | |
279 | * | |
280 | * end_goal is more or less random, but it has to be | |
281 | * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the | |
282 | * next 64-bit boundary is simple.. | |
283 | */ | |
284 | k = (goal + 63) & ~63; | |
285 | goal = ext2_find_next_zero_bit(map, k, goal); | |
286 | if (goal < k) | |
287 | goto got_it; | |
288 | /* | |
289 | * Search in the remainder of the current group. | |
290 | */ | |
291 | } | |
292 | ||
293 | p = map + (goal >> 3); | |
294 | r = memscan(p, 0, (size - goal + 7) >> 3); | |
295 | k = (r - map) << 3; | |
296 | if (k < size) { | |
297 | /* | |
298 | * We have succeeded in finding a free byte in the block | |
299 | * bitmap. Now search backwards to find the start of this | |
300 | * group of free blocks - won't take more than 7 iterations. | |
301 | */ | |
302 | for (goal = k; goal && !ext2_test_bit (goal - 1, map); goal--) | |
303 | ; | |
304 | goto got_it; | |
305 | } | |
306 | ||
307 | k = ext2_find_next_zero_bit ((u32 *)map, size, goal); | |
308 | if (k < size) { | |
309 | goal = k; | |
310 | goto got_it; | |
311 | } | |
312 | return -1; | |
313 | got_it: | |
314 | if (ext2_set_bit_atomic(lock, goal, (void *) map)) | |
315 | goto repeat; | |
316 | return goal; | |
317 | } | |
318 | ||
319 | /* | |
320 | * ext2_new_block uses a goal block to assist allocation. If the goal is | |
321 | * free, or there is a free block within 32 blocks of the goal, that block | |
322 | * is allocated. Otherwise a forward search is made for a free block; within | |
323 | * each block group the search first looks for an entire free byte in the block | |
324 | * bitmap, and then for any free bit if that fails. | |
325 | * This function also updates quota and i_blocks field. | |
326 | */ | |
327 | int ext2_new_block(struct inode *inode, unsigned long goal, | |
328 | u32 *prealloc_count, u32 *prealloc_block, int *err) | |
329 | { | |
330 | struct buffer_head *bitmap_bh = NULL; | |
331 | struct buffer_head *gdp_bh; /* bh2 */ | |
332 | struct ext2_group_desc *desc; | |
333 | int group_no; /* i */ | |
334 | int ret_block; /* j */ | |
335 | int group_idx; /* k */ | |
336 | int target_block; /* tmp */ | |
337 | int block = 0; | |
338 | struct super_block *sb = inode->i_sb; | |
339 | struct ext2_sb_info *sbi = EXT2_SB(sb); | |
340 | struct ext2_super_block *es = sbi->s_es; | |
341 | unsigned group_size = EXT2_BLOCKS_PER_GROUP(sb); | |
342 | unsigned prealloc_goal = es->s_prealloc_blocks; | |
343 | unsigned group_alloc = 0, es_alloc, dq_alloc; | |
344 | int nr_scanned_groups; | |
345 | ||
346 | if (!prealloc_goal--) | |
347 | prealloc_goal = EXT2_DEFAULT_PREALLOC_BLOCKS - 1; | |
348 | if (!prealloc_count || *prealloc_count) | |
349 | prealloc_goal = 0; | |
350 | ||
351 | if (DQUOT_ALLOC_BLOCK(inode, 1)) { | |
352 | *err = -EDQUOT; | |
353 | goto out; | |
354 | } | |
355 | ||
356 | while (prealloc_goal && DQUOT_PREALLOC_BLOCK(inode, prealloc_goal)) | |
357 | prealloc_goal--; | |
358 | ||
359 | dq_alloc = prealloc_goal + 1; | |
360 | es_alloc = reserve_blocks(sb, dq_alloc); | |
361 | if (!es_alloc) { | |
362 | *err = -ENOSPC; | |
363 | goto out_dquot; | |
364 | } | |
365 | ||
366 | ext2_debug ("goal=%lu.\n", goal); | |
367 | ||
368 | if (goal < le32_to_cpu(es->s_first_data_block) || | |
369 | goal >= le32_to_cpu(es->s_blocks_count)) | |
370 | goal = le32_to_cpu(es->s_first_data_block); | |
371 | group_no = (goal - le32_to_cpu(es->s_first_data_block)) / group_size; | |
372 | desc = ext2_get_group_desc (sb, group_no, &gdp_bh); | |
373 | if (!desc) { | |
374 | /* | |
375 | * gdp_bh may still be uninitialised. But group_release_blocks | |
376 | * will not touch it because group_alloc is zero. | |
377 | */ | |
378 | goto io_error; | |
379 | } | |
380 | ||
381 | group_alloc = group_reserve_blocks(sbi, group_no, desc, | |
382 | gdp_bh, es_alloc); | |
383 | if (group_alloc) { | |
384 | ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) % | |
385 | group_size); | |
386 | brelse(bitmap_bh); | |
387 | bitmap_bh = read_block_bitmap(sb, group_no); | |
388 | if (!bitmap_bh) | |
389 | goto io_error; | |
390 | ||
391 | ext2_debug("goal is at %d:%d.\n", group_no, ret_block); | |
392 | ||
393 | ret_block = grab_block(sb_bgl_lock(sbi, group_no), | |
394 | bitmap_bh->b_data, group_size, ret_block); | |
395 | if (ret_block >= 0) | |
396 | goto got_block; | |
397 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
398 | group_alloc = 0; | |
399 | } | |
400 | ||
401 | ext2_debug ("Bit not found in block group %d.\n", group_no); | |
402 | ||
403 | /* | |
404 | * Now search the rest of the groups. We assume that | |
405 | * i and desc correctly point to the last group visited. | |
406 | */ | |
407 | nr_scanned_groups = 0; | |
408 | retry: | |
409 | for (group_idx = 0; !group_alloc && | |
410 | group_idx < sbi->s_groups_count; group_idx++) { | |
411 | group_no++; | |
412 | if (group_no >= sbi->s_groups_count) | |
413 | group_no = 0; | |
414 | desc = ext2_get_group_desc(sb, group_no, &gdp_bh); | |
415 | if (!desc) | |
416 | goto io_error; | |
417 | group_alloc = group_reserve_blocks(sbi, group_no, desc, | |
418 | gdp_bh, es_alloc); | |
419 | } | |
420 | if (!group_alloc) { | |
421 | *err = -ENOSPC; | |
422 | goto out_release; | |
423 | } | |
424 | brelse(bitmap_bh); | |
425 | bitmap_bh = read_block_bitmap(sb, group_no); | |
426 | if (!bitmap_bh) | |
427 | goto io_error; | |
428 | ||
429 | ret_block = grab_block(sb_bgl_lock(sbi, group_no), bitmap_bh->b_data, | |
430 | group_size, 0); | |
431 | if (ret_block < 0) { | |
432 | /* | |
433 | * If a free block counter is corrupted we can loop inifintely. | |
434 | * Detect that here. | |
435 | */ | |
436 | nr_scanned_groups++; | |
437 | if (nr_scanned_groups > 2 * sbi->s_groups_count) { | |
438 | ext2_error(sb, "ext2_new_block", | |
439 | "corrupted free blocks counters"); | |
440 | goto io_error; | |
441 | } | |
442 | /* | |
443 | * Someone else grabbed the last free block in this blockgroup | |
444 | * before us. Retry the scan. | |
445 | */ | |
446 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
447 | group_alloc = 0; | |
448 | goto retry; | |
449 | } | |
450 | ||
451 | got_block: | |
452 | ext2_debug("using block group %d(%d)\n", | |
453 | group_no, desc->bg_free_blocks_count); | |
454 | ||
455 | target_block = ret_block + group_no * group_size + | |
456 | le32_to_cpu(es->s_first_data_block); | |
457 | ||
458 | if (target_block == le32_to_cpu(desc->bg_block_bitmap) || | |
459 | target_block == le32_to_cpu(desc->bg_inode_bitmap) || | |
460 | in_range(target_block, le32_to_cpu(desc->bg_inode_table), | |
461 | sbi->s_itb_per_group)) | |
462 | ext2_error (sb, "ext2_new_block", | |
463 | "Allocating block in system zone - " | |
464 | "block = %u", target_block); | |
465 | ||
466 | if (target_block >= le32_to_cpu(es->s_blocks_count)) { | |
467 | ext2_error (sb, "ext2_new_block", | |
468 | "block(%d) >= blocks count(%d) - " | |
469 | "block_group = %d, es == %p ", ret_block, | |
470 | le32_to_cpu(es->s_blocks_count), group_no, es); | |
471 | goto io_error; | |
472 | } | |
473 | block = target_block; | |
474 | ||
475 | /* OK, we _had_ allocated something */ | |
476 | ext2_debug("found bit %d\n", ret_block); | |
477 | ||
478 | dq_alloc--; | |
479 | es_alloc--; | |
480 | group_alloc--; | |
481 | ||
482 | /* | |
483 | * Do block preallocation now if required. | |
484 | */ | |
485 | write_lock(&EXT2_I(inode)->i_meta_lock); | |
486 | if (group_alloc && !*prealloc_count) { | |
487 | unsigned n; | |
488 | ||
489 | for (n = 0; n < group_alloc && ++ret_block < group_size; n++) { | |
490 | if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group_no), | |
491 | ret_block, | |
492 | (void*) bitmap_bh->b_data)) | |
493 | break; | |
494 | } | |
495 | *prealloc_block = block + 1; | |
496 | *prealloc_count = n; | |
497 | es_alloc -= n; | |
498 | dq_alloc -= n; | |
499 | group_alloc -= n; | |
500 | } | |
501 | write_unlock(&EXT2_I(inode)->i_meta_lock); | |
502 | ||
503 | mark_buffer_dirty(bitmap_bh); | |
504 | if (sb->s_flags & MS_SYNCHRONOUS) | |
505 | sync_dirty_buffer(bitmap_bh); | |
506 | ||
507 | ext2_debug ("allocating block %d. ", block); | |
508 | ||
509 | *err = 0; | |
510 | out_release: | |
511 | group_release_blocks(sb, group_no, desc, gdp_bh, group_alloc); | |
512 | release_blocks(sb, es_alloc); | |
513 | out_dquot: | |
514 | DQUOT_FREE_BLOCK(inode, dq_alloc); | |
515 | out: | |
516 | brelse(bitmap_bh); | |
517 | return block; | |
518 | ||
519 | io_error: | |
520 | *err = -EIO; | |
521 | goto out_release; | |
522 | } | |
523 | ||
524 | unsigned long ext2_count_free_blocks (struct super_block * sb) | |
525 | { | |
526 | struct ext2_group_desc * desc; | |
527 | unsigned long desc_count = 0; | |
528 | int i; | |
529 | #ifdef EXT2FS_DEBUG | |
530 | unsigned long bitmap_count, x; | |
531 | struct ext2_super_block *es; | |
532 | ||
533 | lock_super (sb); | |
534 | es = EXT2_SB(sb)->s_es; | |
535 | desc_count = 0; | |
536 | bitmap_count = 0; | |
537 | desc = NULL; | |
538 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
539 | struct buffer_head *bitmap_bh; | |
540 | desc = ext2_get_group_desc (sb, i, NULL); | |
541 | if (!desc) | |
542 | continue; | |
543 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
544 | bitmap_bh = read_block_bitmap(sb, i); | |
545 | if (!bitmap_bh) | |
546 | continue; | |
547 | ||
548 | x = ext2_count_free(bitmap_bh, sb->s_blocksize); | |
549 | printk ("group %d: stored = %d, counted = %lu\n", | |
550 | i, le16_to_cpu(desc->bg_free_blocks_count), x); | |
551 | bitmap_count += x; | |
552 | brelse(bitmap_bh); | |
553 | } | |
554 | printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n", | |
555 | (long)le32_to_cpu(es->s_free_blocks_count), | |
556 | desc_count, bitmap_count); | |
557 | unlock_super (sb); | |
558 | return bitmap_count; | |
559 | #else | |
560 | for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) { | |
561 | desc = ext2_get_group_desc (sb, i, NULL); | |
562 | if (!desc) | |
563 | continue; | |
564 | desc_count += le16_to_cpu(desc->bg_free_blocks_count); | |
565 | } | |
566 | return desc_count; | |
567 | #endif | |
568 | } | |
569 | ||
570 | static inline int | |
571 | block_in_use(unsigned long block, struct super_block *sb, unsigned char *map) | |
572 | { | |
573 | return ext2_test_bit ((block - | |
574 | le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) % | |
575 | EXT2_BLOCKS_PER_GROUP(sb), map); | |
576 | } | |
577 | ||
578 | static inline int test_root(int a, int b) | |
579 | { | |
580 | int num = b; | |
581 | ||
582 | while (a > num) | |
583 | num *= b; | |
584 | return num == a; | |
585 | } | |
586 | ||
587 | static int ext2_group_sparse(int group) | |
588 | { | |
589 | if (group <= 1) | |
590 | return 1; | |
591 | return (test_root(group, 3) || test_root(group, 5) || | |
592 | test_root(group, 7)); | |
593 | } | |
594 | ||
595 | /** | |
596 | * ext2_bg_has_super - number of blocks used by the superblock in group | |
597 | * @sb: superblock for filesystem | |
598 | * @group: group number to check | |
599 | * | |
600 | * Return the number of blocks used by the superblock (primary or backup) | |
601 | * in this group. Currently this will be only 0 or 1. | |
602 | */ | |
603 | int ext2_bg_has_super(struct super_block *sb, int group) | |
604 | { | |
605 | if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& | |
606 | !ext2_group_sparse(group)) | |
607 | return 0; | |
608 | return 1; | |
609 | } | |
610 | ||
611 | /** | |
612 | * ext2_bg_num_gdb - number of blocks used by the group table in group | |
613 | * @sb: superblock for filesystem | |
614 | * @group: group number to check | |
615 | * | |
616 | * Return the number of blocks used by the group descriptor table | |
617 | * (primary or backup) in this group. In the future there may be a | |
618 | * different number of descriptor blocks in each group. | |
619 | */ | |
620 | unsigned long ext2_bg_num_gdb(struct super_block *sb, int group) | |
621 | { | |
622 | if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&& | |
623 | !ext2_group_sparse(group)) | |
624 | return 0; | |
625 | return EXT2_SB(sb)->s_gdb_count; | |
626 | } | |
627 |