Properly calculate the ronly flag at unmount time.
[dragonfly.git] / sys / vfs / gnu / ext2fs / ext2_linux_balloc.c
CommitLineData
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1/*
2 * modified for Lites 1.1
3 *
4 * Aug 1995, Godmar Back (gback@cs.utah.edu)
5 * University of Utah, Department of Computer Science
6 *
7 * $FreeBSD: src/sys/gnu/ext2fs/ext2_linux_balloc.c,v 1.11.2.3 2001/08/14 18:03:19 gallatin Exp $
54078292 8 * $DragonFly: src/sys/vfs/gnu/ext2fs/ext2_linux_balloc.c,v 1.7 2006/03/24 18:35:33 dillon Exp $
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9 */
10/*
11 * linux/fs/ext2/balloc.c
12 *
13 * Copyright (C) 1992, 1993, 1994, 1995
14 * Remy Card (card@masi.ibp.fr)
15 * Laboratoire MASI - Institut Blaise Pascal
16 * Universite Pierre et Marie Curie (Paris VI)
17 *
18 * Enhanced block allocation by Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
19 */
20
21/*
22 * The free blocks are managed by bitmaps. A file system contains several
23 * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
24 * block for inodes, N blocks for the inode table and data blocks.
25 *
26 * The file system contains group descriptors which are located after the
27 * super block. Each descriptor contains the number of the bitmap block and
28 * the free blocks count in the block. The descriptors are loaded in memory
29 * when a file system is mounted (see ext2_read_super).
30 */
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/buf.h>
35#include <sys/proc.h>
36#include <sys/mount.h>
37#include <sys/vnode.h>
7b95be2a 38#include <sys/buf2.h>
61670a01 39#include <sys/thread2.h>
984263bc 40
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41#include <vfs/ufs/quota.h>
42#include <vfs/ufs/ufsmount.h>
43#include "ext2_extern.h"
44#include "ext2_fs.h"
45#include "ext2_fs_sb.h"
46#include "fs.h"
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47
48#ifdef __i386__
1f2de5d4 49#include "i386-bitops.h"
984263bc 50#elif defined (__alpha__)
1f2de5d4 51#include "alpha-bitops.h"
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52#else
53#error Provide an bitops.h file, please !
54#endif
55
56#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
57
58/* got rid of get_group_desc since it can already be found in
59 * ext2_linux_ialloc.c
60 */
61
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62static void
63read_block_bitmap(struct mount *mp, unsigned int block_group,
64 unsigned long bitmap_nr)
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65{
66 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
67 struct ext2_group_desc * gdp;
68 struct buffer_head * bh;
69 int error;
70
71 gdp = get_group_desc (mp, block_group, NULL);
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72 error = bread(VFSTOUFS(mp)->um_devvp,
73 fsbtodoff(sb, gdp->bg_block_bitmap),
74 sb->s_blocksize, &bh);
75 if (error) {
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76 panic ( "read_block_bitmap: "
77 "Cannot read block bitmap - "
78 "block_group = %d, block_bitmap = %lu",
79 block_group, (unsigned long) gdp->bg_block_bitmap);
54078292 80 }
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81 sb->s_block_bitmap_number[bitmap_nr] = block_group;
82 sb->s_block_bitmap[bitmap_nr] = bh;
83 LCK_BUF(bh)
84}
85
86/*
87 * load_block_bitmap loads the block bitmap for a blocks group
88 *
89 * It maintains a cache for the last bitmaps loaded. This cache is managed
90 * with a LRU algorithm.
91 *
92 * Notes:
93 * 1/ There is one cache per mounted file system.
94 * 2/ If the file system contains less than EXT2_MAX_GROUP_LOADED groups,
95 * this function reads the bitmap without maintaining a LRU cache.
96 */
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97static int
98load__block_bitmap(struct mount *mp, unsigned int block_group)
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99{
100 int i, j;
101 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
102 unsigned long block_bitmap_number;
103 struct buffer_head * block_bitmap;
104
105 if (block_group >= sb->s_groups_count)
106 panic ( "load_block_bitmap: "
107 "block_group >= groups_count - "
108 "block_group = %d, groups_count = %lu",
109 block_group, sb->s_groups_count);
110
111 if (sb->s_groups_count <= EXT2_MAX_GROUP_LOADED) {
112 if (sb->s_block_bitmap[block_group]) {
113 if (sb->s_block_bitmap_number[block_group] !=
114 block_group)
115 panic ( "load_block_bitmap: "
116 "block_group != block_bitmap_number");
117 else
118 return block_group;
119 } else {
120 read_block_bitmap (mp, block_group, block_group);
121 return block_group;
122 }
123 }
124
125 for (i = 0; i < sb->s_loaded_block_bitmaps &&
126 sb->s_block_bitmap_number[i] != block_group; i++)
127 ;
128 if (i < sb->s_loaded_block_bitmaps &&
129 sb->s_block_bitmap_number[i] == block_group) {
130 block_bitmap_number = sb->s_block_bitmap_number[i];
131 block_bitmap = sb->s_block_bitmap[i];
132 for (j = i; j > 0; j--) {
133 sb->s_block_bitmap_number[j] =
134 sb->s_block_bitmap_number[j - 1];
135 sb->s_block_bitmap[j] =
136 sb->s_block_bitmap[j - 1];
137 }
138 sb->s_block_bitmap_number[0] = block_bitmap_number;
139 sb->s_block_bitmap[0] = block_bitmap;
140 } else {
141 if (sb->s_loaded_block_bitmaps < EXT2_MAX_GROUP_LOADED)
142 sb->s_loaded_block_bitmaps++;
143 else
144 ULCK_BUF(sb->s_block_bitmap[EXT2_MAX_GROUP_LOADED - 1])
145
146 for (j = sb->s_loaded_block_bitmaps - 1; j > 0; j--) {
147 sb->s_block_bitmap_number[j] =
148 sb->s_block_bitmap_number[j - 1];
149 sb->s_block_bitmap[j] =
150 sb->s_block_bitmap[j - 1];
151 }
152 read_block_bitmap (mp, block_group, 0);
153 }
154 return 0;
155}
156
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157static __inline int
158load_block_bitmap(struct mount * mp, unsigned int block_group)
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159{
160 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
161 if (sb->s_loaded_block_bitmaps > 0 &&
162 sb->s_block_bitmap_number[0] == block_group)
163 return 0;
164
165 if (sb->s_groups_count <= EXT2_MAX_GROUP_LOADED &&
166 sb->s_block_bitmap_number[block_group] == block_group &&
167 sb->s_block_bitmap[block_group])
168 return block_group;
169
170 return load__block_bitmap (mp, block_group);
171}
172
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173void
174ext2_free_blocks(struct mount * mp, unsigned long block,
175 unsigned long count)
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176{
177 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
178 struct buffer_head * bh;
179 struct buffer_head * bh2;
180 unsigned long block_group;
181 unsigned long bit;
182 unsigned long i;
183 int bitmap_nr;
184 struct ext2_group_desc * gdp;
185 struct ext2_super_block * es = sb->s_es;
186
187 if (!sb) {
188 printf ("ext2_free_blocks: nonexistent device");
189 return;
190 }
191 lock_super (VFSTOUFS(mp)->um_devvp);
192 if (block < es->s_first_data_block ||
193 (block + count) > es->s_blocks_count) {
194 printf ( "ext2_free_blocks: "
195 "Freeing blocks not in datazone - "
196 "block = %lu, count = %lu", block, count);
197 unlock_super (VFSTOUFS(mp)->um_devvp);
198 return;
199 }
200
201 ext2_debug ("freeing blocks %lu to %lu\n", block, block+count-1);
202
203 block_group = (block - es->s_first_data_block) /
204 EXT2_BLOCKS_PER_GROUP(sb);
205 bit = (block - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb);
206 if (bit + count > EXT2_BLOCKS_PER_GROUP(sb))
207 panic ( "ext2_free_blocks: "
208 "Freeing blocks across group boundary - "
209 "Block = %lu, count = %lu",
210 block, count);
211 bitmap_nr = load_block_bitmap (mp, block_group);
212 bh = sb->s_block_bitmap[bitmap_nr];
213 gdp = get_group_desc (mp, block_group, &bh2);
214
215 if (/* test_opt (sb, CHECK_STRICT) && assume always strict ! */
216 (in_range (gdp->bg_block_bitmap, block, count) ||
217 in_range (gdp->bg_inode_bitmap, block, count) ||
218 in_range (block, gdp->bg_inode_table,
219 sb->s_itb_per_group) ||
220 in_range (block + count - 1, gdp->bg_inode_table,
221 sb->s_itb_per_group)))
222 panic ( "ext2_free_blocks: "
223 "Freeing blocks in system zones - "
224 "Block = %lu, count = %lu",
225 block, count);
226
227 for (i = 0; i < count; i++) {
228 if (!clear_bit (bit + i, bh->b_data))
229 printf ("ext2_free_blocks: "
230 "bit already cleared for block %lu",
231 block);
232 else {
233 gdp->bg_free_blocks_count++;
234 es->s_free_blocks_count++;
235 }
236 }
237
238 mark_buffer_dirty(bh2);
239 mark_buffer_dirty(bh);
240/****
241 if (sb->s_flags & MS_SYNCHRONOUS) {
242 ll_rw_block (WRITE, 1, &bh);
243 wait_on_buffer (bh);
244 }
245****/
246 sb->s_dirt = 1;
247 unlock_super (VFSTOUFS(mp)->um_devvp);
248 return;
249}
250
251/*
252 * ext2_new_block uses a goal block to assist allocation. If the goal is
253 * free, or there is a free block within 32 blocks of the goal, that block
254 * is allocated. Otherwise a forward search is made for a free block; within
255 * each block group the search first looks for an entire free byte in the block
256 * bitmap, and then for any free bit if that fails.
257 */
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258int
259ext2_new_block(struct mount * mp, unsigned long goal,
260 u_int32_t * prealloc_count,
261 u_int32_t * prealloc_block)
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262{
263 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
264 struct buffer_head * bh;
265 struct buffer_head * bh2;
266 char * p, * r;
267 int i, j, k, tmp;
268 int bitmap_nr;
269 struct ext2_group_desc * gdp;
270 struct ext2_super_block * es = sb->s_es;
271
272#ifdef EXT2FS_DEBUG
273 static int goal_hits = 0, goal_attempts = 0;
274#endif
275 if (!sb) {
276 printf ("ext2_new_block: nonexistent device");
277 return 0;
278 }
279 lock_super (VFSTOUFS(mp)->um_devvp);
280
281 ext2_debug ("goal=%lu.\n", goal);
282
283repeat:
284 /*
285 * First, test whether the goal block is free.
286 */
287 if (goal < es->s_first_data_block || goal >= es->s_blocks_count)
288 goal = es->s_first_data_block;
289 i = (goal - es->s_first_data_block) / EXT2_BLOCKS_PER_GROUP(sb);
290 gdp = get_group_desc (mp, i, &bh2);
291 if (gdp->bg_free_blocks_count > 0) {
292 j = ((goal - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb));
293#ifdef EXT2FS_DEBUG
294 if (j)
295 goal_attempts++;
296#endif
297 bitmap_nr = load_block_bitmap (mp, i);
298 bh = sb->s_block_bitmap[bitmap_nr];
299
300 ext2_debug ("goal is at %d:%d.\n", i, j);
301
302 if (!test_bit(j, bh->b_data)) {
303#ifdef EXT2FS_DEBUG
304 goal_hits++;
305 ext2_debug ("goal bit allocated.\n");
306#endif
307 goto got_block;
308 }
309 if (j) {
310 /*
311 * The goal was occupied; search forward for a free
312 * block within the next XX blocks.
313 *
314 * end_goal is more or less random, but it has to be
315 * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
316 * next 64-bit boundary is simple..
317 */
318 int end_goal = (j + 63) & ~63;
319 j = find_next_zero_bit(bh->b_data, end_goal, j);
320 if (j < end_goal)
321 goto got_block;
322 }
323
324 ext2_debug ("Bit not found near goal\n");
325
326 /*
327 * There has been no free block found in the near vicinity
328 * of the goal: do a search forward through the block groups,
329 * searching in each group first for an entire free byte in
330 * the bitmap and then for any free bit.
331 *
332 * Search first in the remainder of the current group; then,
333 * cyclicly search through the rest of the groups.
334 */
335 p = ((char *) bh->b_data) + (j >> 3);
336 r = memscan(p, 0, (EXT2_BLOCKS_PER_GROUP(sb) - j + 7) >> 3);
337 k = (r - ((char *) bh->b_data)) << 3;
338 if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
339 j = k;
340 goto search_back;
341 }
342 k = find_next_zero_bit ((unsigned long *) bh->b_data,
343 EXT2_BLOCKS_PER_GROUP(sb),
344 j);
345 if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
346 j = k;
347 goto got_block;
348 }
349 }
350
351 ext2_debug ("Bit not found in block group %d.\n", i);
352
353 /*
354 * Now search the rest of the groups. We assume that
355 * i and gdp correctly point to the last group visited.
356 */
357 for (k = 0; k < sb->s_groups_count; k++) {
358 i++;
359 if (i >= sb->s_groups_count)
360 i = 0;
361 gdp = get_group_desc (mp, i, &bh2);
362 if (gdp->bg_free_blocks_count > 0)
363 break;
364 }
365 if (k >= sb->s_groups_count) {
366 unlock_super (VFSTOUFS(mp)->um_devvp);
367 return 0;
368 }
369 bitmap_nr = load_block_bitmap (mp, i);
370 bh = sb->s_block_bitmap[bitmap_nr];
371 r = memscan(bh->b_data, 0, EXT2_BLOCKS_PER_GROUP(sb) >> 3);
372 j = (r - bh->b_data) << 3;
373
374 if (j < EXT2_BLOCKS_PER_GROUP(sb))
375 goto search_back;
376 else
377 j = find_first_zero_bit ((unsigned long *) bh->b_data,
378 EXT2_BLOCKS_PER_GROUP(sb));
379 if (j >= EXT2_BLOCKS_PER_GROUP(sb)) {
380 printf ( "ext2_new_block: "
381 "Free blocks count corrupted for block group %d", i);
382 unlock_super (VFSTOUFS(mp)->um_devvp);
383 return 0;
384 }
385
386search_back:
387 /*
388 * We have succeeded in finding a free byte in the block
389 * bitmap. Now search backwards up to 7 bits to find the
390 * start of this group of free blocks.
391 */
392 for (k = 0; k < 7 && j > 0 && !test_bit (j - 1, bh->b_data); k++, j--);
393
394got_block:
395
396 ext2_debug ("using block group %d(%d)\n", i, gdp->bg_free_blocks_count);
397
398 tmp = j + i * EXT2_BLOCKS_PER_GROUP(sb) + es->s_first_data_block;
399
400 if (/* test_opt (sb, CHECK_STRICT) && we are always strict. */
401 (tmp == gdp->bg_block_bitmap ||
402 tmp == gdp->bg_inode_bitmap ||
403 in_range (tmp, gdp->bg_inode_table, sb->s_itb_per_group)))
404 panic ( "ext2_new_block: "
405 "Allocating block in system zone - "
406 "%dth block = %u in group %u", j, tmp, i);
407
408 if (set_bit (j, bh->b_data)) {
409 printf ( "ext2_new_block: "
410 "bit already set for block %d", j);
411 goto repeat;
412 }
413
414 ext2_debug ("found bit %d\n", j);
415
416 /*
417 * Do block preallocation now if required.
418 */
419#ifdef EXT2_PREALLOCATE
420 if (prealloc_block) {
421 *prealloc_count = 0;
422 *prealloc_block = tmp + 1;
423 for (k = 1;
424 k < 8 && (j + k) < EXT2_BLOCKS_PER_GROUP(sb); k++) {
425 if (set_bit (j + k, bh->b_data))
426 break;
427 (*prealloc_count)++;
428 }
429 gdp->bg_free_blocks_count -= *prealloc_count;
430 es->s_free_blocks_count -= *prealloc_count;
431 ext2_debug ("Preallocated a further %lu bits.\n",
432 *prealloc_count);
433 }
434#endif
435
436 j = tmp;
437
438 mark_buffer_dirty(bh);
439/****
440 if (sb->s_flags & MS_SYNCHRONOUS) {
441 ll_rw_block (WRITE, 1, &bh);
442 wait_on_buffer (bh);
443 }
444****/
445 if (j >= es->s_blocks_count) {
446 printf ( "ext2_new_block: "
447 "block >= blocks count - "
448 "block_group = %d, block=%d", i, j);
449 unlock_super (VFSTOUFS(mp)->um_devvp);
450 return 0;
451 }
452
453 ext2_debug ("allocating block %d. "
454 "Goal hits %d of %d.\n", j, goal_hits, goal_attempts);
455
456 gdp->bg_free_blocks_count--;
457 mark_buffer_dirty(bh2);
458 es->s_free_blocks_count--;
459 sb->s_dirt = 1;
460 unlock_super (VFSTOUFS(mp)->um_devvp);
461 return j;
462}
463
464#ifdef unused
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465static unsigned long
466ext2_count_free_blocks(struct mount * mp)
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467{
468 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
469#ifdef EXT2FS_DEBUG
470 struct ext2_super_block * es;
471 unsigned long desc_count, bitmap_count, x;
472 int bitmap_nr;
473 struct ext2_group_desc * gdp;
474 int i;
475
476 lock_super (VFSTOUFS(mp)->um_devvp);
477 es = sb->s_es;
478 desc_count = 0;
479 bitmap_count = 0;
480 gdp = NULL;
481 for (i = 0; i < sb->s_groups_count; i++) {
482 gdp = get_group_desc (mp, i, NULL);
483 desc_count += gdp->bg_free_blocks_count;
484 bitmap_nr = load_block_bitmap (mp, i);
485 x = ext2_count_free (sb->s_block_bitmap[bitmap_nr],
486 sb->s_blocksize);
487 ext2_debug ("group %d: stored = %d, counted = %lu\n",
488 i, gdp->bg_free_blocks_count, x);
489 bitmap_count += x;
490 }
491 ext2_debug( "stored = %lu, computed = %lu, %lu\n",
492 es->s_free_blocks_count, desc_count, bitmap_count);
493 unlock_super (VFSTOUFS(mp)->um_devvp);
494 return bitmap_count;
495#else
496 return sb->s_es->s_free_blocks_count;
497#endif
498}
499#endif /* unused */
500
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501static __inline int
502block_in_use (unsigned long block, struct ext2_sb_info *sb,
503 unsigned char * map)
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504{
505 return test_bit ((block - sb->s_es->s_first_data_block) %
506 EXT2_BLOCKS_PER_GROUP(sb), map);
507}
508
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509static int
510test_root(int a, int b)
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511{
512 if (a == 0)
513 return 1;
514 while (1) {
515 if (a == 1)
516 return 1;
517 if (a % b)
518 return 0;
519 a = a / b;
520 }
521}
522
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523int
524ext2_group_sparse(int group)
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525{
526 return (test_root(group, 3) || test_root(group, 5) ||
527 test_root(group, 7));
528}
529
530#ifdef unused
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531static void
532ext2_check_blocks_bitmap(struct mount * mp)
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533{
534 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
535 struct buffer_head * bh;
536 struct ext2_super_block * es;
537 unsigned long desc_count, bitmap_count, x;
538 unsigned long desc_blocks;
539 int bitmap_nr;
540 struct ext2_group_desc * gdp;
541 int i, j;
542
543 lock_super (VFSTOUFS(mp)->um_devvp);
544 es = sb->s_es;
545 desc_count = 0;
546 bitmap_count = 0;
547 gdp = NULL;
548 desc_blocks = (sb->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
549 EXT2_DESC_PER_BLOCK(sb);
550 for (i = 0; i < sb->s_groups_count; i++) {
551 gdp = get_group_desc (mp, i, NULL);
552 desc_count += gdp->bg_free_blocks_count;
553 bitmap_nr = load_block_bitmap (mp, i);
554 bh = sb->s_block_bitmap[bitmap_nr];
555
556 if (!(es->s_feature_ro_compat &
557 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER) ||
558 ext2_group_sparse(i)) {
559 if (!test_bit (0, bh->b_data))
560 printf ("ext2_check_blocks_bitmap: "
561 "Superblock in group %d "
562 "is marked free", i);
563
564 for (j = 0; j < desc_blocks; j++)
565 if (!test_bit (j + 1, bh->b_data))
566 printf ("ext2_check_blocks_bitmap: "
567 "Descriptor block #%d in group "
568 "%d is marked free", j, i);
569 }
570
571 if (!block_in_use (gdp->bg_block_bitmap, sb, bh->b_data))
572 printf ("ext2_check_blocks_bitmap: "
573 "Block bitmap for group %d is marked free",
574 i);
575
576 if (!block_in_use (gdp->bg_inode_bitmap, sb, bh->b_data))
577 printf ("ext2_check_blocks_bitmap: "
578 "Inode bitmap for group %d is marked free",
579 i);
580
581 for (j = 0; j < sb->s_itb_per_group; j++)
582 if (!block_in_use (gdp->bg_inode_table + j, sb, bh->b_data))
583 printf ("ext2_check_blocks_bitmap: "
584 "Block #%d of the inode table in "
585 "group %d is marked free", j, i);
586
587 x = ext2_count_free (bh, sb->s_blocksize);
588 if (gdp->bg_free_blocks_count != x)
589 printf ("ext2_check_blocks_bitmap: "
590 "Wrong free blocks count for group %d, "
591 "stored = %d, counted = %lu", i,
592 gdp->bg_free_blocks_count, x);
593 bitmap_count += x;
594 }
595 if (es->s_free_blocks_count != bitmap_count)
596 printf ("ext2_check_blocks_bitmap: "
597 "Wrong free blocks count in super block, "
598 "stored = %lu, counted = %lu",
599 (unsigned long) es->s_free_blocks_count, bitmap_count);
600 unlock_super (VFSTOUFS(mp)->um_devvp);
601}
602#endif /* unused */
603
604/*
605 * this function is taken from
606 * linux/fs/ext2/bitmap.c
607 */
608
609static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
610
611unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
612{
613 unsigned int i;
614 unsigned long sum = 0;
615
616 if (!map)
617 return (0);
618 for (i = 0; i < numchars; i++)
619 sum += nibblemap[map->b_data[i] & 0xf] +
620 nibblemap[(map->b_data[i] >> 4) & 0xf];
621 return (sum);
622}