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xfs: convert directory db conversion to xfs_da_geometry
[deliverable/linux.git] / fs / xfs / xfs_dir2.c
1 /*
2 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_format.h"
21 #include "xfs_log_format.h"
22 #include "xfs_trans_resv.h"
23 #include "xfs_inum.h"
24 #include "xfs_sb.h"
25 #include "xfs_ag.h"
26 #include "xfs_mount.h"
27 #include "xfs_da_format.h"
28 #include "xfs_da_btree.h"
29 #include "xfs_inode.h"
30 #include "xfs_trans.h"
31 #include "xfs_inode_item.h"
32 #include "xfs_bmap.h"
33 #include "xfs_dir2.h"
34 #include "xfs_dir2_priv.h"
35 #include "xfs_error.h"
36 #include "xfs_trace.h"
37 #include "xfs_dinode.h"
38
39 struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2, XFS_DIR3_FT_DIR };
40
41
42 /*
43 * ASCII case-insensitive (ie. A-Z) support for directories that was
44 * used in IRIX.
45 */
46 STATIC xfs_dahash_t
47 xfs_ascii_ci_hashname(
48 struct xfs_name *name)
49 {
50 xfs_dahash_t hash;
51 int i;
52
53 for (i = 0, hash = 0; i < name->len; i++)
54 hash = tolower(name->name[i]) ^ rol32(hash, 7);
55
56 return hash;
57 }
58
59 STATIC enum xfs_dacmp
60 xfs_ascii_ci_compname(
61 struct xfs_da_args *args,
62 const unsigned char *name,
63 int len)
64 {
65 enum xfs_dacmp result;
66 int i;
67
68 if (args->namelen != len)
69 return XFS_CMP_DIFFERENT;
70
71 result = XFS_CMP_EXACT;
72 for (i = 0; i < len; i++) {
73 if (args->name[i] == name[i])
74 continue;
75 if (tolower(args->name[i]) != tolower(name[i]))
76 return XFS_CMP_DIFFERENT;
77 result = XFS_CMP_CASE;
78 }
79
80 return result;
81 }
82
83 static struct xfs_nameops xfs_ascii_ci_nameops = {
84 .hashname = xfs_ascii_ci_hashname,
85 .compname = xfs_ascii_ci_compname,
86 };
87
88 int
89 xfs_da_mount(
90 struct xfs_mount *mp)
91 {
92 struct xfs_da_geometry *dageo;
93 int nodehdr_size;
94
95
96 ASSERT(xfs_sb_version_hasdirv2(&mp->m_sb));
97 ASSERT((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) <=
98 XFS_MAX_BLOCKSIZE);
99
100 mp->m_dir_inode_ops = xfs_dir_get_ops(mp, NULL);
101 mp->m_nondir_inode_ops = xfs_nondir_get_ops(mp, NULL);
102
103 nodehdr_size = mp->m_dir_inode_ops->node_hdr_size;
104 mp->m_dir_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
105 KM_SLEEP | KM_MAYFAIL);
106 mp->m_attr_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
107 KM_SLEEP | KM_MAYFAIL);
108 if (!mp->m_dir_geo || !mp->m_attr_geo) {
109 kmem_free(mp->m_dir_geo);
110 kmem_free(mp->m_attr_geo);
111 return ENOMEM;
112 }
113
114 /* set up directory geometry */
115 dageo = mp->m_dir_geo;
116 dageo->blklog = mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog;
117 dageo->fsblog = mp->m_sb.sb_blocklog;
118 dageo->blksize = 1 << dageo->blklog;
119 dageo->fsbcount = 1 << mp->m_sb.sb_dirblklog;
120
121 /*
122 * Now we've set up the block conversion variables, we can calculate the
123 * segment block constants using the geometry structure.
124 */
125 dageo->datablk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_DATA_OFFSET);
126 dageo->leafblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_LEAF_OFFSET);
127 dageo->freeblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_FREE_OFFSET);
128 dageo->node_ents = (dageo->blksize - nodehdr_size) /
129 (uint)sizeof(xfs_da_node_entry_t);
130 dageo->magicpct = (dageo->blksize * 37) / 100;
131
132 /* set up attribute geometry - single fsb only */
133 dageo = mp->m_attr_geo;
134 dageo->blklog = mp->m_sb.sb_blocklog;
135 dageo->fsblog = mp->m_sb.sb_blocklog;
136 dageo->blksize = 1 << dageo->blklog;
137 dageo->fsbcount = 1;
138 dageo->node_ents = (dageo->blksize - nodehdr_size) /
139 (uint)sizeof(xfs_da_node_entry_t);
140 dageo->magicpct = (dageo->blksize * 37) / 100;
141
142 if (xfs_sb_version_hasasciici(&mp->m_sb))
143 mp->m_dirnameops = &xfs_ascii_ci_nameops;
144 else
145 mp->m_dirnameops = &xfs_default_nameops;
146
147 /* XXX: these are to be removed as code is converted to use geo */
148 mp->m_dirblksize = mp->m_dir_geo->blksize;
149 mp->m_dirblkfsbs = mp->m_dir_geo->fsbcount;
150 mp->m_dirdatablk = mp->m_dir_geo->datablk;
151 mp->m_dirleafblk = mp->m_dir_geo->leafblk;
152 mp->m_dirfreeblk = mp->m_dir_geo->freeblk;
153 mp->m_dir_node_ents = mp->m_dir_geo->node_ents;
154 mp->m_dir_magicpct = mp->m_dir_geo->magicpct;
155 mp->m_attr_node_ents = mp->m_attr_geo->node_ents;
156 mp->m_attr_magicpct = mp->m_attr_geo->magicpct;
157 return 0;
158 }
159
160 void
161 xfs_da_unmount(
162 struct xfs_mount *mp)
163 {
164 kmem_free(mp->m_dir_geo);
165 kmem_free(mp->m_attr_geo);
166 }
167
168 /*
169 * Return 1 if directory contains only "." and "..".
170 */
171 int
172 xfs_dir_isempty(
173 xfs_inode_t *dp)
174 {
175 xfs_dir2_sf_hdr_t *sfp;
176
177 ASSERT(S_ISDIR(dp->i_d.di_mode));
178 if (dp->i_d.di_size == 0) /* might happen during shutdown. */
179 return 1;
180 if (dp->i_d.di_size > XFS_IFORK_DSIZE(dp))
181 return 0;
182 sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
183 return !sfp->count;
184 }
185
186 /*
187 * Validate a given inode number.
188 */
189 int
190 xfs_dir_ino_validate(
191 xfs_mount_t *mp,
192 xfs_ino_t ino)
193 {
194 xfs_agblock_t agblkno;
195 xfs_agino_t agino;
196 xfs_agnumber_t agno;
197 int ino_ok;
198 int ioff;
199
200 agno = XFS_INO_TO_AGNO(mp, ino);
201 agblkno = XFS_INO_TO_AGBNO(mp, ino);
202 ioff = XFS_INO_TO_OFFSET(mp, ino);
203 agino = XFS_OFFBNO_TO_AGINO(mp, agblkno, ioff);
204 ino_ok =
205 agno < mp->m_sb.sb_agcount &&
206 agblkno < mp->m_sb.sb_agblocks &&
207 agblkno != 0 &&
208 ioff < (1 << mp->m_sb.sb_inopblog) &&
209 XFS_AGINO_TO_INO(mp, agno, agino) == ino;
210 if (unlikely(XFS_TEST_ERROR(!ino_ok, mp, XFS_ERRTAG_DIR_INO_VALIDATE,
211 XFS_RANDOM_DIR_INO_VALIDATE))) {
212 xfs_warn(mp, "Invalid inode number 0x%Lx",
213 (unsigned long long) ino);
214 XFS_ERROR_REPORT("xfs_dir_ino_validate", XFS_ERRLEVEL_LOW, mp);
215 return XFS_ERROR(EFSCORRUPTED);
216 }
217 return 0;
218 }
219
220 /*
221 * Initialize a directory with its "." and ".." entries.
222 */
223 int
224 xfs_dir_init(
225 xfs_trans_t *tp,
226 xfs_inode_t *dp,
227 xfs_inode_t *pdp)
228 {
229 struct xfs_da_args *args;
230 int error;
231
232 ASSERT(S_ISDIR(dp->i_d.di_mode));
233 error = xfs_dir_ino_validate(tp->t_mountp, pdp->i_ino);
234 if (error)
235 return error;
236
237 args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
238 if (!args)
239 return ENOMEM;
240
241 args->geo = dp->i_mount->m_dir_geo;
242 args->dp = dp;
243 args->trans = tp;
244 error = xfs_dir2_sf_create(args, pdp->i_ino);
245 kmem_free(args);
246 return error;
247 }
248
249 /*
250 Enter a name in a directory.
251 */
252 int
253 xfs_dir_createname(
254 xfs_trans_t *tp,
255 xfs_inode_t *dp,
256 struct xfs_name *name,
257 xfs_ino_t inum, /* new entry inode number */
258 xfs_fsblock_t *first, /* bmap's firstblock */
259 xfs_bmap_free_t *flist, /* bmap's freeblock list */
260 xfs_extlen_t total) /* bmap's total block count */
261 {
262 struct xfs_da_args *args;
263 int rval;
264 int v; /* type-checking value */
265
266 ASSERT(S_ISDIR(dp->i_d.di_mode));
267 rval = xfs_dir_ino_validate(tp->t_mountp, inum);
268 if (rval)
269 return rval;
270 XFS_STATS_INC(xs_dir_create);
271
272 args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
273 if (!args)
274 return ENOMEM;
275
276 args->geo = dp->i_mount->m_dir_geo;
277 args->name = name->name;
278 args->namelen = name->len;
279 args->filetype = name->type;
280 args->hashval = dp->i_mount->m_dirnameops->hashname(name);
281 args->inumber = inum;
282 args->dp = dp;
283 args->firstblock = first;
284 args->flist = flist;
285 args->total = total;
286 args->whichfork = XFS_DATA_FORK;
287 args->trans = tp;
288 args->op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
289
290 if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
291 rval = xfs_dir2_sf_addname(args);
292 goto out_free;
293 }
294
295 rval = xfs_dir2_isblock(dp, &v);
296 if (rval)
297 goto out_free;
298 if (v) {
299 rval = xfs_dir2_block_addname(args);
300 goto out_free;
301 }
302
303 rval = xfs_dir2_isleaf(dp, &v);
304 if (rval)
305 goto out_free;
306 if (v)
307 rval = xfs_dir2_leaf_addname(args);
308 else
309 rval = xfs_dir2_node_addname(args);
310
311 out_free:
312 kmem_free(args);
313 return rval;
314 }
315
316 /*
317 * If doing a CI lookup and case-insensitive match, dup actual name into
318 * args.value. Return EEXIST for success (ie. name found) or an error.
319 */
320 int
321 xfs_dir_cilookup_result(
322 struct xfs_da_args *args,
323 const unsigned char *name,
324 int len)
325 {
326 if (args->cmpresult == XFS_CMP_DIFFERENT)
327 return ENOENT;
328 if (args->cmpresult != XFS_CMP_CASE ||
329 !(args->op_flags & XFS_DA_OP_CILOOKUP))
330 return EEXIST;
331
332 args->value = kmem_alloc(len, KM_NOFS | KM_MAYFAIL);
333 if (!args->value)
334 return ENOMEM;
335
336 memcpy(args->value, name, len);
337 args->valuelen = len;
338 return EEXIST;
339 }
340
341 /*
342 * Lookup a name in a directory, give back the inode number.
343 * If ci_name is not NULL, returns the actual name in ci_name if it differs
344 * to name, or ci_name->name is set to NULL for an exact match.
345 */
346
347 int
348 xfs_dir_lookup(
349 xfs_trans_t *tp,
350 xfs_inode_t *dp,
351 struct xfs_name *name,
352 xfs_ino_t *inum, /* out: inode number */
353 struct xfs_name *ci_name) /* out: actual name if CI match */
354 {
355 struct xfs_da_args *args;
356 int rval;
357 int v; /* type-checking value */
358
359 ASSERT(S_ISDIR(dp->i_d.di_mode));
360 XFS_STATS_INC(xs_dir_lookup);
361
362 /*
363 * We need to use KM_NOFS here so that lockdep will not throw false
364 * positive deadlock warnings on a non-transactional lookup path. It is
365 * safe to recurse into inode recalim in that case, but lockdep can't
366 * easily be taught about it. Hence KM_NOFS avoids having to add more
367 * lockdep Doing this avoids having to add a bunch of lockdep class
368 * annotations into the reclaim path for the ilock.
369 */
370 args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
371 args->geo = dp->i_mount->m_dir_geo;
372 args->name = name->name;
373 args->namelen = name->len;
374 args->filetype = name->type;
375 args->hashval = dp->i_mount->m_dirnameops->hashname(name);
376 args->dp = dp;
377 args->whichfork = XFS_DATA_FORK;
378 args->trans = tp;
379 args->op_flags = XFS_DA_OP_OKNOENT;
380 if (ci_name)
381 args->op_flags |= XFS_DA_OP_CILOOKUP;
382
383 if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
384 rval = xfs_dir2_sf_lookup(args);
385 goto out_check_rval;
386 }
387
388 rval = xfs_dir2_isblock(dp, &v);
389 if (rval)
390 goto out_free;
391 if (v) {
392 rval = xfs_dir2_block_lookup(args);
393 goto out_check_rval;
394 }
395
396 rval = xfs_dir2_isleaf(dp, &v);
397 if (rval)
398 goto out_free;
399 if (v)
400 rval = xfs_dir2_leaf_lookup(args);
401 else
402 rval = xfs_dir2_node_lookup(args);
403
404 out_check_rval:
405 if (rval == EEXIST)
406 rval = 0;
407 if (!rval) {
408 *inum = args->inumber;
409 if (ci_name) {
410 ci_name->name = args->value;
411 ci_name->len = args->valuelen;
412 }
413 }
414 out_free:
415 kmem_free(args);
416 return rval;
417 }
418
419 /*
420 * Remove an entry from a directory.
421 */
422 int
423 xfs_dir_removename(
424 xfs_trans_t *tp,
425 xfs_inode_t *dp,
426 struct xfs_name *name,
427 xfs_ino_t ino,
428 xfs_fsblock_t *first, /* bmap's firstblock */
429 xfs_bmap_free_t *flist, /* bmap's freeblock list */
430 xfs_extlen_t total) /* bmap's total block count */
431 {
432 struct xfs_da_args *args;
433 int rval;
434 int v; /* type-checking value */
435
436 ASSERT(S_ISDIR(dp->i_d.di_mode));
437 XFS_STATS_INC(xs_dir_remove);
438
439 args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
440 if (!args)
441 return ENOMEM;
442
443 args->geo = dp->i_mount->m_dir_geo;
444 args->name = name->name;
445 args->namelen = name->len;
446 args->filetype = name->type;
447 args->hashval = dp->i_mount->m_dirnameops->hashname(name);
448 args->inumber = ino;
449 args->dp = dp;
450 args->firstblock = first;
451 args->flist = flist;
452 args->total = total;
453 args->whichfork = XFS_DATA_FORK;
454 args->trans = tp;
455
456 if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
457 rval = xfs_dir2_sf_removename(args);
458 goto out_free;
459 }
460
461 rval = xfs_dir2_isblock(dp, &v);
462 if (rval)
463 goto out_free;
464 if (v) {
465 rval = xfs_dir2_block_removename(args);
466 goto out_free;
467 }
468
469 rval = xfs_dir2_isleaf(dp, &v);
470 if (rval)
471 goto out_free;
472 if (v)
473 rval = xfs_dir2_leaf_removename(args);
474 else
475 rval = xfs_dir2_node_removename(args);
476 out_free:
477 kmem_free(args);
478 return rval;
479 }
480
481 /*
482 * Replace the inode number of a directory entry.
483 */
484 int
485 xfs_dir_replace(
486 xfs_trans_t *tp,
487 xfs_inode_t *dp,
488 struct xfs_name *name, /* name of entry to replace */
489 xfs_ino_t inum, /* new inode number */
490 xfs_fsblock_t *first, /* bmap's firstblock */
491 xfs_bmap_free_t *flist, /* bmap's freeblock list */
492 xfs_extlen_t total) /* bmap's total block count */
493 {
494 struct xfs_da_args *args;
495 int rval;
496 int v; /* type-checking value */
497
498 ASSERT(S_ISDIR(dp->i_d.di_mode));
499
500 rval = xfs_dir_ino_validate(tp->t_mountp, inum);
501 if (rval)
502 return rval;
503
504 args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
505 if (!args)
506 return ENOMEM;
507
508 args->geo = dp->i_mount->m_dir_geo;
509 args->name = name->name;
510 args->namelen = name->len;
511 args->filetype = name->type;
512 args->hashval = dp->i_mount->m_dirnameops->hashname(name);
513 args->inumber = inum;
514 args->dp = dp;
515 args->firstblock = first;
516 args->flist = flist;
517 args->total = total;
518 args->whichfork = XFS_DATA_FORK;
519 args->trans = tp;
520
521 if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
522 rval = xfs_dir2_sf_replace(args);
523 goto out_free;
524 }
525
526 rval = xfs_dir2_isblock(dp, &v);
527 if (rval)
528 goto out_free;
529 if (v) {
530 rval = xfs_dir2_block_replace(args);
531 goto out_free;
532 }
533
534 rval = xfs_dir2_isleaf(dp, &v);
535 if (rval)
536 goto out_free;
537 if (v)
538 rval = xfs_dir2_leaf_replace(args);
539 else
540 rval = xfs_dir2_node_replace(args);
541 out_free:
542 kmem_free(args);
543 return rval;
544 }
545
546 /*
547 * See if this entry can be added to the directory without allocating space.
548 * First checks that the caller couldn't reserve enough space (resblks = 0).
549 */
550 int
551 xfs_dir_canenter(
552 xfs_trans_t *tp,
553 xfs_inode_t *dp,
554 struct xfs_name *name, /* name of entry to add */
555 uint resblks)
556 {
557 struct xfs_da_args *args;
558 int rval;
559 int v; /* type-checking value */
560
561 if (resblks)
562 return 0;
563
564 ASSERT(S_ISDIR(dp->i_d.di_mode));
565
566 args = kmem_zalloc(sizeof(*args), KM_SLEEP | KM_NOFS);
567 if (!args)
568 return ENOMEM;
569
570 args->geo = dp->i_mount->m_dir_geo;
571 args->name = name->name;
572 args->namelen = name->len;
573 args->filetype = name->type;
574 args->hashval = dp->i_mount->m_dirnameops->hashname(name);
575 args->dp = dp;
576 args->whichfork = XFS_DATA_FORK;
577 args->trans = tp;
578 args->op_flags = XFS_DA_OP_JUSTCHECK | XFS_DA_OP_ADDNAME |
579 XFS_DA_OP_OKNOENT;
580
581 if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
582 rval = xfs_dir2_sf_addname(args);
583 goto out_free;
584 }
585
586 rval = xfs_dir2_isblock(dp, &v);
587 if (rval)
588 goto out_free;
589 if (v) {
590 rval = xfs_dir2_block_addname(args);
591 goto out_free;
592 }
593
594 rval = xfs_dir2_isleaf(dp, &v);
595 if (rval)
596 goto out_free;
597 if (v)
598 rval = xfs_dir2_leaf_addname(args);
599 else
600 rval = xfs_dir2_node_addname(args);
601 out_free:
602 kmem_free(args);
603 return rval;
604 }
605
606 /*
607 * Utility routines.
608 */
609
610 /*
611 * Add a block to the directory.
612 *
613 * This routine is for data and free blocks, not leaf/node blocks which are
614 * handled by xfs_da_grow_inode.
615 */
616 int
617 xfs_dir2_grow_inode(
618 struct xfs_da_args *args,
619 int space, /* v2 dir's space XFS_DIR2_xxx_SPACE */
620 xfs_dir2_db_t *dbp) /* out: block number added */
621 {
622 struct xfs_inode *dp = args->dp;
623 struct xfs_mount *mp = dp->i_mount;
624 xfs_fileoff_t bno; /* directory offset of new block */
625 int count; /* count of filesystem blocks */
626 int error;
627
628 trace_xfs_dir2_grow_inode(args, space);
629
630 /*
631 * Set lowest possible block in the space requested.
632 */
633 bno = XFS_B_TO_FSBT(mp, space * XFS_DIR2_SPACE_SIZE);
634 count = mp->m_dirblkfsbs;
635
636 error = xfs_da_grow_inode_int(args, &bno, count);
637 if (error)
638 return error;
639
640 *dbp = xfs_dir2_da_to_db(args->geo, (xfs_dablk_t)bno);
641
642 /*
643 * Update file's size if this is the data space and it grew.
644 */
645 if (space == XFS_DIR2_DATA_SPACE) {
646 xfs_fsize_t size; /* directory file (data) size */
647
648 size = XFS_FSB_TO_B(mp, bno + count);
649 if (size > dp->i_d.di_size) {
650 dp->i_d.di_size = size;
651 xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
652 }
653 }
654 return 0;
655 }
656
657 /*
658 * See if the directory is a single-block form directory.
659 */
660 int
661 xfs_dir2_isblock(
662 xfs_inode_t *dp,
663 int *vp) /* out: 1 is block, 0 is not block */
664 {
665 xfs_fileoff_t last; /* last file offset */
666 xfs_mount_t *mp;
667 int rval;
668
669 mp = dp->i_mount;
670 if ((rval = xfs_bmap_last_offset(dp, &last, XFS_DATA_FORK)))
671 return rval;
672 rval = XFS_FSB_TO_B(mp, last) == mp->m_dirblksize;
673 ASSERT(rval == 0 || dp->i_d.di_size == mp->m_dirblksize);
674 *vp = rval;
675 return 0;
676 }
677
678 /*
679 * See if the directory is a single-leaf form directory.
680 */
681 int
682 xfs_dir2_isleaf(
683 xfs_inode_t *dp,
684 int *vp) /* out: 1 is leaf, 0 is not leaf */
685 {
686 xfs_fileoff_t last; /* last file offset */
687 xfs_mount_t *mp;
688 int rval;
689
690 mp = dp->i_mount;
691 if ((rval = xfs_bmap_last_offset(dp, &last, XFS_DATA_FORK)))
692 return rval;
693 *vp = last == mp->m_dirleafblk + (1 << mp->m_sb.sb_dirblklog);
694 return 0;
695 }
696
697 /*
698 * Remove the given block from the directory.
699 * This routine is used for data and free blocks, leaf/node are done
700 * by xfs_da_shrink_inode.
701 */
702 int
703 xfs_dir2_shrink_inode(
704 xfs_da_args_t *args,
705 xfs_dir2_db_t db,
706 struct xfs_buf *bp)
707 {
708 xfs_fileoff_t bno; /* directory file offset */
709 xfs_dablk_t da; /* directory file offset */
710 int done; /* bunmap is finished */
711 xfs_inode_t *dp;
712 int error;
713 xfs_mount_t *mp;
714 xfs_trans_t *tp;
715
716 trace_xfs_dir2_shrink_inode(args, db);
717
718 dp = args->dp;
719 mp = dp->i_mount;
720 tp = args->trans;
721 da = xfs_dir2_db_to_da(args->geo, db);
722 /*
723 * Unmap the fsblock(s).
724 */
725 if ((error = xfs_bunmapi(tp, dp, da, mp->m_dirblkfsbs,
726 XFS_BMAPI_METADATA, 0, args->firstblock, args->flist,
727 &done))) {
728 /*
729 * ENOSPC actually can happen if we're in a removename with
730 * no space reservation, and the resulting block removal
731 * would cause a bmap btree split or conversion from extents
732 * to btree. This can only happen for un-fragmented
733 * directory blocks, since you need to be punching out
734 * the middle of an extent.
735 * In this case we need to leave the block in the file,
736 * and not binval it.
737 * So the block has to be in a consistent empty state
738 * and appropriately logged.
739 * We don't free up the buffer, the caller can tell it
740 * hasn't happened since it got an error back.
741 */
742 return error;
743 }
744 ASSERT(done);
745 /*
746 * Invalidate the buffer from the transaction.
747 */
748 xfs_trans_binval(tp, bp);
749 /*
750 * If it's not a data block, we're done.
751 */
752 if (db >= xfs_dir2_byte_to_db(args->geo, XFS_DIR2_LEAF_OFFSET))
753 return 0;
754 /*
755 * If the block isn't the last one in the directory, we're done.
756 */
757 if (dp->i_d.di_size > xfs_dir2_db_off_to_byte(args->geo, db + 1, 0))
758 return 0;
759 bno = da;
760 if ((error = xfs_bmap_last_before(tp, dp, &bno, XFS_DATA_FORK))) {
761 /*
762 * This can't really happen unless there's kernel corruption.
763 */
764 return error;
765 }
766 if (db == mp->m_dirdatablk)
767 ASSERT(bno == 0);
768 else
769 ASSERT(bno > 0);
770 /*
771 * Set the size to the new last block.
772 */
773 dp->i_d.di_size = XFS_FSB_TO_B(mp, bno);
774 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
775 return 0;
776 }
Linux kernel - Deliverables
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