Hardwire i386 instead of using the borken machine variable
[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 $
7b95be2a 8 * $DragonFly: src/sys/vfs/gnu/ext2fs/ext2_linux_balloc.c,v 1.3 2003/07/21 07:57:43 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>
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39
40#include <ufs/ufs/quota.h>
41#include <ufs/ufs/ufsmount.h>
42#include <gnu/ext2fs/ext2_extern.h>
43#include <gnu/ext2fs/ext2_fs.h>
44#include <gnu/ext2fs/ext2_fs_sb.h>
45#include <gnu/ext2fs/fs.h>
46
47#ifdef __i386__
48#include <gnu/ext2fs/i386-bitops.h>
49#elif defined (__alpha__)
50#include <gnu/ext2fs/alpha-bitops.h>
51#else
52#error Provide an bitops.h file, please !
53#endif
54
55#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
56
57/* got rid of get_group_desc since it can already be found in
58 * ext2_linux_ialloc.c
59 */
60
61static void read_block_bitmap (struct mount * mp,
62 unsigned int block_group,
63 unsigned long bitmap_nr)
64{
65 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
66 struct ext2_group_desc * gdp;
67 struct buffer_head * bh;
68 int error;
69
70 gdp = get_group_desc (mp, block_group, NULL);
71 if ((error = bread (VFSTOUFS(mp)->um_devvp,
7b95be2a 72 fsbtodb(sb, gdp->bg_block_bitmap),sb->s_blocksize, &bh)) != 0)
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73 panic ( "read_block_bitmap: "
74 "Cannot read block bitmap - "
75 "block_group = %d, block_bitmap = %lu",
76 block_group, (unsigned long) gdp->bg_block_bitmap);
77 sb->s_block_bitmap_number[bitmap_nr] = block_group;
78 sb->s_block_bitmap[bitmap_nr] = bh;
79 LCK_BUF(bh)
80}
81
82/*
83 * load_block_bitmap loads the block bitmap for a blocks group
84 *
85 * It maintains a cache for the last bitmaps loaded. This cache is managed
86 * with a LRU algorithm.
87 *
88 * Notes:
89 * 1/ There is one cache per mounted file system.
90 * 2/ If the file system contains less than EXT2_MAX_GROUP_LOADED groups,
91 * this function reads the bitmap without maintaining a LRU cache.
92 */
93static int load__block_bitmap (struct mount * mp,
94 unsigned int block_group)
95{
96 int i, j;
97 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
98 unsigned long block_bitmap_number;
99 struct buffer_head * block_bitmap;
100
101 if (block_group >= sb->s_groups_count)
102 panic ( "load_block_bitmap: "
103 "block_group >= groups_count - "
104 "block_group = %d, groups_count = %lu",
105 block_group, sb->s_groups_count);
106
107 if (sb->s_groups_count <= EXT2_MAX_GROUP_LOADED) {
108 if (sb->s_block_bitmap[block_group]) {
109 if (sb->s_block_bitmap_number[block_group] !=
110 block_group)
111 panic ( "load_block_bitmap: "
112 "block_group != block_bitmap_number");
113 else
114 return block_group;
115 } else {
116 read_block_bitmap (mp, block_group, block_group);
117 return block_group;
118 }
119 }
120
121 for (i = 0; i < sb->s_loaded_block_bitmaps &&
122 sb->s_block_bitmap_number[i] != block_group; i++)
123 ;
124 if (i < sb->s_loaded_block_bitmaps &&
125 sb->s_block_bitmap_number[i] == block_group) {
126 block_bitmap_number = sb->s_block_bitmap_number[i];
127 block_bitmap = sb->s_block_bitmap[i];
128 for (j = i; j > 0; j--) {
129 sb->s_block_bitmap_number[j] =
130 sb->s_block_bitmap_number[j - 1];
131 sb->s_block_bitmap[j] =
132 sb->s_block_bitmap[j - 1];
133 }
134 sb->s_block_bitmap_number[0] = block_bitmap_number;
135 sb->s_block_bitmap[0] = block_bitmap;
136 } else {
137 if (sb->s_loaded_block_bitmaps < EXT2_MAX_GROUP_LOADED)
138 sb->s_loaded_block_bitmaps++;
139 else
140 ULCK_BUF(sb->s_block_bitmap[EXT2_MAX_GROUP_LOADED - 1])
141
142 for (j = sb->s_loaded_block_bitmaps - 1; j > 0; j--) {
143 sb->s_block_bitmap_number[j] =
144 sb->s_block_bitmap_number[j - 1];
145 sb->s_block_bitmap[j] =
146 sb->s_block_bitmap[j - 1];
147 }
148 read_block_bitmap (mp, block_group, 0);
149 }
150 return 0;
151}
152
153static __inline int load_block_bitmap (struct mount * mp,
154 unsigned int block_group)
155{
156 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
157 if (sb->s_loaded_block_bitmaps > 0 &&
158 sb->s_block_bitmap_number[0] == block_group)
159 return 0;
160
161 if (sb->s_groups_count <= EXT2_MAX_GROUP_LOADED &&
162 sb->s_block_bitmap_number[block_group] == block_group &&
163 sb->s_block_bitmap[block_group])
164 return block_group;
165
166 return load__block_bitmap (mp, block_group);
167}
168
169void ext2_free_blocks (struct mount * mp, unsigned long block,
170 unsigned long count)
171{
172 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
173 struct buffer_head * bh;
174 struct buffer_head * bh2;
175 unsigned long block_group;
176 unsigned long bit;
177 unsigned long i;
178 int bitmap_nr;
179 struct ext2_group_desc * gdp;
180 struct ext2_super_block * es = sb->s_es;
181
182 if (!sb) {
183 printf ("ext2_free_blocks: nonexistent device");
184 return;
185 }
186 lock_super (VFSTOUFS(mp)->um_devvp);
187 if (block < es->s_first_data_block ||
188 (block + count) > es->s_blocks_count) {
189 printf ( "ext2_free_blocks: "
190 "Freeing blocks not in datazone - "
191 "block = %lu, count = %lu", block, count);
192 unlock_super (VFSTOUFS(mp)->um_devvp);
193 return;
194 }
195
196 ext2_debug ("freeing blocks %lu to %lu\n", block, block+count-1);
197
198 block_group = (block - es->s_first_data_block) /
199 EXT2_BLOCKS_PER_GROUP(sb);
200 bit = (block - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb);
201 if (bit + count > EXT2_BLOCKS_PER_GROUP(sb))
202 panic ( "ext2_free_blocks: "
203 "Freeing blocks across group boundary - "
204 "Block = %lu, count = %lu",
205 block, count);
206 bitmap_nr = load_block_bitmap (mp, block_group);
207 bh = sb->s_block_bitmap[bitmap_nr];
208 gdp = get_group_desc (mp, block_group, &bh2);
209
210 if (/* test_opt (sb, CHECK_STRICT) && assume always strict ! */
211 (in_range (gdp->bg_block_bitmap, block, count) ||
212 in_range (gdp->bg_inode_bitmap, block, count) ||
213 in_range (block, gdp->bg_inode_table,
214 sb->s_itb_per_group) ||
215 in_range (block + count - 1, gdp->bg_inode_table,
216 sb->s_itb_per_group)))
217 panic ( "ext2_free_blocks: "
218 "Freeing blocks in system zones - "
219 "Block = %lu, count = %lu",
220 block, count);
221
222 for (i = 0; i < count; i++) {
223 if (!clear_bit (bit + i, bh->b_data))
224 printf ("ext2_free_blocks: "
225 "bit already cleared for block %lu",
226 block);
227 else {
228 gdp->bg_free_blocks_count++;
229 es->s_free_blocks_count++;
230 }
231 }
232
233 mark_buffer_dirty(bh2);
234 mark_buffer_dirty(bh);
235/****
236 if (sb->s_flags & MS_SYNCHRONOUS) {
237 ll_rw_block (WRITE, 1, &bh);
238 wait_on_buffer (bh);
239 }
240****/
241 sb->s_dirt = 1;
242 unlock_super (VFSTOUFS(mp)->um_devvp);
243 return;
244}
245
246/*
247 * ext2_new_block uses a goal block to assist allocation. If the goal is
248 * free, or there is a free block within 32 blocks of the goal, that block
249 * is allocated. Otherwise a forward search is made for a free block; within
250 * each block group the search first looks for an entire free byte in the block
251 * bitmap, and then for any free bit if that fails.
252 */
253int ext2_new_block (struct mount * mp, unsigned long goal,
254 u_int32_t * prealloc_count,
255 u_int32_t * prealloc_block)
256{
257 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
258 struct buffer_head * bh;
259 struct buffer_head * bh2;
260 char * p, * r;
261 int i, j, k, tmp;
262 int bitmap_nr;
263 struct ext2_group_desc * gdp;
264 struct ext2_super_block * es = sb->s_es;
265
266#ifdef EXT2FS_DEBUG
267 static int goal_hits = 0, goal_attempts = 0;
268#endif
269 if (!sb) {
270 printf ("ext2_new_block: nonexistent device");
271 return 0;
272 }
273 lock_super (VFSTOUFS(mp)->um_devvp);
274
275 ext2_debug ("goal=%lu.\n", goal);
276
277repeat:
278 /*
279 * First, test whether the goal block is free.
280 */
281 if (goal < es->s_first_data_block || goal >= es->s_blocks_count)
282 goal = es->s_first_data_block;
283 i = (goal - es->s_first_data_block) / EXT2_BLOCKS_PER_GROUP(sb);
284 gdp = get_group_desc (mp, i, &bh2);
285 if (gdp->bg_free_blocks_count > 0) {
286 j = ((goal - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb));
287#ifdef EXT2FS_DEBUG
288 if (j)
289 goal_attempts++;
290#endif
291 bitmap_nr = load_block_bitmap (mp, i);
292 bh = sb->s_block_bitmap[bitmap_nr];
293
294 ext2_debug ("goal is at %d:%d.\n", i, j);
295
296 if (!test_bit(j, bh->b_data)) {
297#ifdef EXT2FS_DEBUG
298 goal_hits++;
299 ext2_debug ("goal bit allocated.\n");
300#endif
301 goto got_block;
302 }
303 if (j) {
304 /*
305 * The goal was occupied; search forward for a free
306 * block within the next XX blocks.
307 *
308 * end_goal is more or less random, but it has to be
309 * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
310 * next 64-bit boundary is simple..
311 */
312 int end_goal = (j + 63) & ~63;
313 j = find_next_zero_bit(bh->b_data, end_goal, j);
314 if (j < end_goal)
315 goto got_block;
316 }
317
318 ext2_debug ("Bit not found near goal\n");
319
320 /*
321 * There has been no free block found in the near vicinity
322 * of the goal: do a search forward through the block groups,
323 * searching in each group first for an entire free byte in
324 * the bitmap and then for any free bit.
325 *
326 * Search first in the remainder of the current group; then,
327 * cyclicly search through the rest of the groups.
328 */
329 p = ((char *) bh->b_data) + (j >> 3);
330 r = memscan(p, 0, (EXT2_BLOCKS_PER_GROUP(sb) - j + 7) >> 3);
331 k = (r - ((char *) bh->b_data)) << 3;
332 if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
333 j = k;
334 goto search_back;
335 }
336 k = find_next_zero_bit ((unsigned long *) bh->b_data,
337 EXT2_BLOCKS_PER_GROUP(sb),
338 j);
339 if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
340 j = k;
341 goto got_block;
342 }
343 }
344
345 ext2_debug ("Bit not found in block group %d.\n", i);
346
347 /*
348 * Now search the rest of the groups. We assume that
349 * i and gdp correctly point to the last group visited.
350 */
351 for (k = 0; k < sb->s_groups_count; k++) {
352 i++;
353 if (i >= sb->s_groups_count)
354 i = 0;
355 gdp = get_group_desc (mp, i, &bh2);
356 if (gdp->bg_free_blocks_count > 0)
357 break;
358 }
359 if (k >= sb->s_groups_count) {
360 unlock_super (VFSTOUFS(mp)->um_devvp);
361 return 0;
362 }
363 bitmap_nr = load_block_bitmap (mp, i);
364 bh = sb->s_block_bitmap[bitmap_nr];
365 r = memscan(bh->b_data, 0, EXT2_BLOCKS_PER_GROUP(sb) >> 3);
366 j = (r - bh->b_data) << 3;
367
368 if (j < EXT2_BLOCKS_PER_GROUP(sb))
369 goto search_back;
370 else
371 j = find_first_zero_bit ((unsigned long *) bh->b_data,
372 EXT2_BLOCKS_PER_GROUP(sb));
373 if (j >= EXT2_BLOCKS_PER_GROUP(sb)) {
374 printf ( "ext2_new_block: "
375 "Free blocks count corrupted for block group %d", i);
376 unlock_super (VFSTOUFS(mp)->um_devvp);
377 return 0;
378 }
379
380search_back:
381 /*
382 * We have succeeded in finding a free byte in the block
383 * bitmap. Now search backwards up to 7 bits to find the
384 * start of this group of free blocks.
385 */
386 for (k = 0; k < 7 && j > 0 && !test_bit (j - 1, bh->b_data); k++, j--);
387
388got_block:
389
390 ext2_debug ("using block group %d(%d)\n", i, gdp->bg_free_blocks_count);
391
392 tmp = j + i * EXT2_BLOCKS_PER_GROUP(sb) + es->s_first_data_block;
393
394 if (/* test_opt (sb, CHECK_STRICT) && we are always strict. */
395 (tmp == gdp->bg_block_bitmap ||
396 tmp == gdp->bg_inode_bitmap ||
397 in_range (tmp, gdp->bg_inode_table, sb->s_itb_per_group)))
398 panic ( "ext2_new_block: "
399 "Allocating block in system zone - "
400 "%dth block = %u in group %u", j, tmp, i);
401
402 if (set_bit (j, bh->b_data)) {
403 printf ( "ext2_new_block: "
404 "bit already set for block %d", j);
405 goto repeat;
406 }
407
408 ext2_debug ("found bit %d\n", j);
409
410 /*
411 * Do block preallocation now if required.
412 */
413#ifdef EXT2_PREALLOCATE
414 if (prealloc_block) {
415 *prealloc_count = 0;
416 *prealloc_block = tmp + 1;
417 for (k = 1;
418 k < 8 && (j + k) < EXT2_BLOCKS_PER_GROUP(sb); k++) {
419 if (set_bit (j + k, bh->b_data))
420 break;
421 (*prealloc_count)++;
422 }
423 gdp->bg_free_blocks_count -= *prealloc_count;
424 es->s_free_blocks_count -= *prealloc_count;
425 ext2_debug ("Preallocated a further %lu bits.\n",
426 *prealloc_count);
427 }
428#endif
429
430 j = tmp;
431
432 mark_buffer_dirty(bh);
433/****
434 if (sb->s_flags & MS_SYNCHRONOUS) {
435 ll_rw_block (WRITE, 1, &bh);
436 wait_on_buffer (bh);
437 }
438****/
439 if (j >= es->s_blocks_count) {
440 printf ( "ext2_new_block: "
441 "block >= blocks count - "
442 "block_group = %d, block=%d", i, j);
443 unlock_super (VFSTOUFS(mp)->um_devvp);
444 return 0;
445 }
446
447 ext2_debug ("allocating block %d. "
448 "Goal hits %d of %d.\n", j, goal_hits, goal_attempts);
449
450 gdp->bg_free_blocks_count--;
451 mark_buffer_dirty(bh2);
452 es->s_free_blocks_count--;
453 sb->s_dirt = 1;
454 unlock_super (VFSTOUFS(mp)->um_devvp);
455 return j;
456}
457
458#ifdef unused
459static unsigned long ext2_count_free_blocks (struct mount * mp)
460{
461 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
462#ifdef EXT2FS_DEBUG
463 struct ext2_super_block * es;
464 unsigned long desc_count, bitmap_count, x;
465 int bitmap_nr;
466 struct ext2_group_desc * gdp;
467 int i;
468
469 lock_super (VFSTOUFS(mp)->um_devvp);
470 es = sb->s_es;
471 desc_count = 0;
472 bitmap_count = 0;
473 gdp = NULL;
474 for (i = 0; i < sb->s_groups_count; i++) {
475 gdp = get_group_desc (mp, i, NULL);
476 desc_count += gdp->bg_free_blocks_count;
477 bitmap_nr = load_block_bitmap (mp, i);
478 x = ext2_count_free (sb->s_block_bitmap[bitmap_nr],
479 sb->s_blocksize);
480 ext2_debug ("group %d: stored = %d, counted = %lu\n",
481 i, gdp->bg_free_blocks_count, x);
482 bitmap_count += x;
483 }
484 ext2_debug( "stored = %lu, computed = %lu, %lu\n",
485 es->s_free_blocks_count, desc_count, bitmap_count);
486 unlock_super (VFSTOUFS(mp)->um_devvp);
487 return bitmap_count;
488#else
489 return sb->s_es->s_free_blocks_count;
490#endif
491}
492#endif /* unused */
493
494static __inline int block_in_use (unsigned long block,
495 struct ext2_sb_info * sb,
496 unsigned char * map)
497{
498 return test_bit ((block - sb->s_es->s_first_data_block) %
499 EXT2_BLOCKS_PER_GROUP(sb), map);
500}
501
502static int test_root(int a, int b)
503{
504 if (a == 0)
505 return 1;
506 while (1) {
507 if (a == 1)
508 return 1;
509 if (a % b)
510 return 0;
511 a = a / b;
512 }
513}
514
515int ext2_group_sparse(int group)
516{
517 return (test_root(group, 3) || test_root(group, 5) ||
518 test_root(group, 7));
519}
520
521#ifdef unused
522static void ext2_check_blocks_bitmap (struct mount * mp)
523{
524 struct ext2_sb_info *sb = VFSTOUFS(mp)->um_e2fs;
525 struct buffer_head * bh;
526 struct ext2_super_block * es;
527 unsigned long desc_count, bitmap_count, x;
528 unsigned long desc_blocks;
529 int bitmap_nr;
530 struct ext2_group_desc * gdp;
531 int i, j;
532
533 lock_super (VFSTOUFS(mp)->um_devvp);
534 es = sb->s_es;
535 desc_count = 0;
536 bitmap_count = 0;
537 gdp = NULL;
538 desc_blocks = (sb->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
539 EXT2_DESC_PER_BLOCK(sb);
540 for (i = 0; i < sb->s_groups_count; i++) {
541 gdp = get_group_desc (mp, i, NULL);
542 desc_count += gdp->bg_free_blocks_count;
543 bitmap_nr = load_block_bitmap (mp, i);
544 bh = sb->s_block_bitmap[bitmap_nr];
545
546 if (!(es->s_feature_ro_compat &
547 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER) ||
548 ext2_group_sparse(i)) {
549 if (!test_bit (0, bh->b_data))
550 printf ("ext2_check_blocks_bitmap: "
551 "Superblock in group %d "
552 "is marked free", i);
553
554 for (j = 0; j < desc_blocks; j++)
555 if (!test_bit (j + 1, bh->b_data))
556 printf ("ext2_check_blocks_bitmap: "
557 "Descriptor block #%d in group "
558 "%d is marked free", j, i);
559 }
560
561 if (!block_in_use (gdp->bg_block_bitmap, sb, bh->b_data))
562 printf ("ext2_check_blocks_bitmap: "
563 "Block bitmap for group %d is marked free",
564 i);
565
566 if (!block_in_use (gdp->bg_inode_bitmap, sb, bh->b_data))
567 printf ("ext2_check_blocks_bitmap: "
568 "Inode bitmap for group %d is marked free",
569 i);
570
571 for (j = 0; j < sb->s_itb_per_group; j++)
572 if (!block_in_use (gdp->bg_inode_table + j, sb, bh->b_data))
573 printf ("ext2_check_blocks_bitmap: "
574 "Block #%d of the inode table in "
575 "group %d is marked free", j, i);
576
577 x = ext2_count_free (bh, sb->s_blocksize);
578 if (gdp->bg_free_blocks_count != x)
579 printf ("ext2_check_blocks_bitmap: "
580 "Wrong free blocks count for group %d, "
581 "stored = %d, counted = %lu", i,
582 gdp->bg_free_blocks_count, x);
583 bitmap_count += x;
584 }
585 if (es->s_free_blocks_count != bitmap_count)
586 printf ("ext2_check_blocks_bitmap: "
587 "Wrong free blocks count in super block, "
588 "stored = %lu, counted = %lu",
589 (unsigned long) es->s_free_blocks_count, bitmap_count);
590 unlock_super (VFSTOUFS(mp)->um_devvp);
591}
592#endif /* unused */
593
594/*
595 * this function is taken from
596 * linux/fs/ext2/bitmap.c
597 */
598
599static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
600
601unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
602{
603 unsigned int i;
604 unsigned long sum = 0;
605
606 if (!map)
607 return (0);
608 for (i = 0; i < numchars; i++)
609 sum += nibblemap[map->b_data[i] & 0xf] +
610 nibblemap[(map->b_data[i] >> 4) & 0xf];
611 return (sum);
612}