xref: /linux/fs/xfs/libxfs/xfs_dir2.c (revision 2f804aca48322f02a8f44cca540663845ee80fb1)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
4  * All Rights Reserved.
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_mount.h"
13 #include "xfs_inode.h"
14 #include "xfs_trans.h"
15 #include "xfs_bmap.h"
16 #include "xfs_dir2.h"
17 #include "xfs_dir2_priv.h"
18 #include "xfs_errortag.h"
19 #include "xfs_error.h"
20 #include "xfs_trace.h"
21 
22 const struct xfs_name xfs_name_dotdot = {
23 	.name	= (const unsigned char *)"..",
24 	.len	= 2,
25 	.type	= XFS_DIR3_FT_DIR,
26 };
27 
28 /*
29  * Convert inode mode to directory entry filetype
30  */
31 unsigned char
32 xfs_mode_to_ftype(
33 	int		mode)
34 {
35 	switch (mode & S_IFMT) {
36 	case S_IFREG:
37 		return XFS_DIR3_FT_REG_FILE;
38 	case S_IFDIR:
39 		return XFS_DIR3_FT_DIR;
40 	case S_IFCHR:
41 		return XFS_DIR3_FT_CHRDEV;
42 	case S_IFBLK:
43 		return XFS_DIR3_FT_BLKDEV;
44 	case S_IFIFO:
45 		return XFS_DIR3_FT_FIFO;
46 	case S_IFSOCK:
47 		return XFS_DIR3_FT_SOCK;
48 	case S_IFLNK:
49 		return XFS_DIR3_FT_SYMLINK;
50 	default:
51 		return XFS_DIR3_FT_UNKNOWN;
52 	}
53 }
54 
55 /*
56  * ASCII case-insensitive (ie. A-Z) support for directories that was
57  * used in IRIX.
58  */
59 xfs_dahash_t
60 xfs_ascii_ci_hashname(
61 	const struct xfs_name	*name)
62 {
63 	xfs_dahash_t		hash;
64 	int			i;
65 
66 	for (i = 0, hash = 0; i < name->len; i++)
67 		hash = xfs_ascii_ci_xfrm(name->name[i]) ^ rol32(hash, 7);
68 
69 	return hash;
70 }
71 
72 enum xfs_dacmp
73 xfs_ascii_ci_compname(
74 	struct xfs_da_args	*args,
75 	const unsigned char	*name,
76 	int			len)
77 {
78 	enum xfs_dacmp		result;
79 	int			i;
80 
81 	if (args->namelen != len)
82 		return XFS_CMP_DIFFERENT;
83 
84 	result = XFS_CMP_EXACT;
85 	for (i = 0; i < len; i++) {
86 		if (args->name[i] == name[i])
87 			continue;
88 		if (xfs_ascii_ci_xfrm(args->name[i]) !=
89 		    xfs_ascii_ci_xfrm(name[i]))
90 			return XFS_CMP_DIFFERENT;
91 		result = XFS_CMP_CASE;
92 	}
93 
94 	return result;
95 }
96 
97 int
98 xfs_da_mount(
99 	struct xfs_mount	*mp)
100 {
101 	struct xfs_da_geometry	*dageo;
102 
103 
104 	ASSERT(mp->m_sb.sb_versionnum & XFS_SB_VERSION_DIRV2BIT);
105 	ASSERT(xfs_dir2_dirblock_bytes(&mp->m_sb) <= XFS_MAX_BLOCKSIZE);
106 
107 	mp->m_dir_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
108 				    KM_MAYFAIL);
109 	mp->m_attr_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
110 				     KM_MAYFAIL);
111 	if (!mp->m_dir_geo || !mp->m_attr_geo) {
112 		kmem_free(mp->m_dir_geo);
113 		kmem_free(mp->m_attr_geo);
114 		return -ENOMEM;
115 	}
116 
117 	/* set up directory geometry */
118 	dageo = mp->m_dir_geo;
119 	dageo->blklog = mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog;
120 	dageo->fsblog = mp->m_sb.sb_blocklog;
121 	dageo->blksize = xfs_dir2_dirblock_bytes(&mp->m_sb);
122 	dageo->fsbcount = 1 << mp->m_sb.sb_dirblklog;
123 	if (xfs_has_crc(mp)) {
124 		dageo->node_hdr_size = sizeof(struct xfs_da3_node_hdr);
125 		dageo->leaf_hdr_size = sizeof(struct xfs_dir3_leaf_hdr);
126 		dageo->free_hdr_size = sizeof(struct xfs_dir3_free_hdr);
127 		dageo->data_entry_offset =
128 				sizeof(struct xfs_dir3_data_hdr);
129 	} else {
130 		dageo->node_hdr_size = sizeof(struct xfs_da_node_hdr);
131 		dageo->leaf_hdr_size = sizeof(struct xfs_dir2_leaf_hdr);
132 		dageo->free_hdr_size = sizeof(struct xfs_dir2_free_hdr);
133 		dageo->data_entry_offset =
134 				sizeof(struct xfs_dir2_data_hdr);
135 	}
136 	dageo->leaf_max_ents = (dageo->blksize - dageo->leaf_hdr_size) /
137 			sizeof(struct xfs_dir2_leaf_entry);
138 	dageo->free_max_bests = (dageo->blksize - dageo->free_hdr_size) /
139 			sizeof(xfs_dir2_data_off_t);
140 
141 	dageo->data_first_offset = dageo->data_entry_offset +
142 			xfs_dir2_data_entsize(mp, 1) +
143 			xfs_dir2_data_entsize(mp, 2);
144 
145 	/*
146 	 * Now we've set up the block conversion variables, we can calculate the
147 	 * segment block constants using the geometry structure.
148 	 */
149 	dageo->datablk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_DATA_OFFSET);
150 	dageo->leafblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_LEAF_OFFSET);
151 	dageo->freeblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_FREE_OFFSET);
152 	dageo->node_ents = (dageo->blksize - dageo->node_hdr_size) /
153 				(uint)sizeof(xfs_da_node_entry_t);
154 	dageo->max_extents = (XFS_DIR2_MAX_SPACES * XFS_DIR2_SPACE_SIZE) >>
155 					mp->m_sb.sb_blocklog;
156 	dageo->magicpct = (dageo->blksize * 37) / 100;
157 
158 	/* set up attribute geometry - single fsb only */
159 	dageo = mp->m_attr_geo;
160 	dageo->blklog = mp->m_sb.sb_blocklog;
161 	dageo->fsblog = mp->m_sb.sb_blocklog;
162 	dageo->blksize = 1 << dageo->blklog;
163 	dageo->fsbcount = 1;
164 	dageo->node_hdr_size = mp->m_dir_geo->node_hdr_size;
165 	dageo->node_ents = (dageo->blksize - dageo->node_hdr_size) /
166 				(uint)sizeof(xfs_da_node_entry_t);
167 
168 	if (xfs_has_large_extent_counts(mp))
169 		dageo->max_extents = XFS_MAX_EXTCNT_ATTR_FORK_LARGE;
170 	else
171 		dageo->max_extents = XFS_MAX_EXTCNT_ATTR_FORK_SMALL;
172 
173 	dageo->magicpct = (dageo->blksize * 37) / 100;
174 	return 0;
175 }
176 
177 void
178 xfs_da_unmount(
179 	struct xfs_mount	*mp)
180 {
181 	kmem_free(mp->m_dir_geo);
182 	kmem_free(mp->m_attr_geo);
183 }
184 
185 /*
186  * Return 1 if directory contains only "." and "..".
187  */
188 int
189 xfs_dir_isempty(
190 	xfs_inode_t	*dp)
191 {
192 	xfs_dir2_sf_hdr_t	*sfp;
193 
194 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
195 	if (dp->i_disk_size == 0)	/* might happen during shutdown. */
196 		return 1;
197 	if (dp->i_disk_size > xfs_inode_data_fork_size(dp))
198 		return 0;
199 	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
200 	return !sfp->count;
201 }
202 
203 /*
204  * Validate a given inode number.
205  */
206 int
207 xfs_dir_ino_validate(
208 	xfs_mount_t	*mp,
209 	xfs_ino_t	ino)
210 {
211 	bool		ino_ok = xfs_verify_dir_ino(mp, ino);
212 
213 	if (XFS_IS_CORRUPT(mp, !ino_ok) ||
214 	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_DIR_INO_VALIDATE)) {
215 		xfs_warn(mp, "Invalid inode number 0x%Lx",
216 				(unsigned long long) ino);
217 		return -EFSCORRUPTED;
218 	}
219 	return 0;
220 }
221 
222 /*
223  * Initialize a directory with its "." and ".." entries.
224  */
225 int
226 xfs_dir_init(
227 	xfs_trans_t	*tp,
228 	xfs_inode_t	*dp,
229 	xfs_inode_t	*pdp)
230 {
231 	struct xfs_da_args *args;
232 	int		error;
233 
234 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
235 	error = xfs_dir_ino_validate(tp->t_mountp, pdp->i_ino);
236 	if (error)
237 		return error;
238 
239 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
240 	if (!args)
241 		return -ENOMEM;
242 
243 	args->geo = dp->i_mount->m_dir_geo;
244 	args->dp = dp;
245 	args->trans = tp;
246 	error = xfs_dir2_sf_create(args, pdp->i_ino);
247 	kmem_free(args);
248 	return error;
249 }
250 
251 /*
252  * Enter a name in a directory, or check for available space.
253  * If inum is 0, only the available space test is performed.
254  */
255 int
256 xfs_dir_createname(
257 	struct xfs_trans	*tp,
258 	struct xfs_inode	*dp,
259 	const struct xfs_name	*name,
260 	xfs_ino_t		inum,		/* new entry inode number */
261 	xfs_extlen_t		total)		/* bmap's total block count */
262 {
263 	struct xfs_da_args	*args;
264 	int			rval;
265 	bool			v;
266 
267 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
268 
269 	if (inum) {
270 		rval = xfs_dir_ino_validate(tp->t_mountp, inum);
271 		if (rval)
272 			return rval;
273 		XFS_STATS_INC(dp->i_mount, xs_dir_create);
274 	}
275 
276 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
277 	if (!args)
278 		return -ENOMEM;
279 
280 	args->geo = dp->i_mount->m_dir_geo;
281 	args->name = name->name;
282 	args->namelen = name->len;
283 	args->filetype = name->type;
284 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
285 	args->inumber = inum;
286 	args->dp = dp;
287 	args->total = total;
288 	args->whichfork = XFS_DATA_FORK;
289 	args->trans = tp;
290 	args->op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
291 	if (!inum)
292 		args->op_flags |= XFS_DA_OP_JUSTCHECK;
293 
294 	if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
295 		rval = xfs_dir2_sf_addname(args);
296 		goto out_free;
297 	}
298 
299 	rval = xfs_dir2_isblock(args, &v);
300 	if (rval)
301 		goto out_free;
302 	if (v) {
303 		rval = xfs_dir2_block_addname(args);
304 		goto out_free;
305 	}
306 
307 	rval = xfs_dir2_isleaf(args, &v);
308 	if (rval)
309 		goto out_free;
310 	if (v)
311 		rval = xfs_dir2_leaf_addname(args);
312 	else
313 		rval = xfs_dir2_node_addname(args);
314 
315 out_free:
316 	kmem_free(args);
317 	return rval;
318 }
319 
320 /*
321  * If doing a CI lookup and case-insensitive match, dup actual name into
322  * args.value. Return EEXIST for success (ie. name found) or an error.
323  */
324 int
325 xfs_dir_cilookup_result(
326 	struct xfs_da_args *args,
327 	const unsigned char *name,
328 	int		len)
329 {
330 	if (args->cmpresult == XFS_CMP_DIFFERENT)
331 		return -ENOENT;
332 	if (args->cmpresult != XFS_CMP_CASE ||
333 					!(args->op_flags & XFS_DA_OP_CILOOKUP))
334 		return -EEXIST;
335 
336 	args->value = kmem_alloc(len, KM_NOFS | KM_MAYFAIL);
337 	if (!args->value)
338 		return -ENOMEM;
339 
340 	memcpy(args->value, name, len);
341 	args->valuelen = len;
342 	return -EEXIST;
343 }
344 
345 /*
346  * Lookup a name in a directory, give back the inode number.
347  * If ci_name is not NULL, returns the actual name in ci_name if it differs
348  * to name, or ci_name->name is set to NULL for an exact match.
349  */
350 
351 int
352 xfs_dir_lookup(
353 	struct xfs_trans	*tp,
354 	struct xfs_inode	*dp,
355 	const struct xfs_name	*name,
356 	xfs_ino_t		*inum,	  /* out: inode number */
357 	struct xfs_name		*ci_name) /* out: actual name if CI match */
358 {
359 	struct xfs_da_args	*args;
360 	int			rval;
361 	bool			v;
362 	int			lock_mode;
363 
364 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
365 	XFS_STATS_INC(dp->i_mount, xs_dir_lookup);
366 
367 	/*
368 	 * We need to use KM_NOFS here so that lockdep will not throw false
369 	 * positive deadlock warnings on a non-transactional lookup path. It is
370 	 * safe to recurse into inode recalim in that case, but lockdep can't
371 	 * easily be taught about it. Hence KM_NOFS avoids having to add more
372 	 * lockdep Doing this avoids having to add a bunch of lockdep class
373 	 * annotations into the reclaim path for the ilock.
374 	 */
375 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
376 	args->geo = dp->i_mount->m_dir_geo;
377 	args->name = name->name;
378 	args->namelen = name->len;
379 	args->filetype = name->type;
380 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
381 	args->dp = dp;
382 	args->whichfork = XFS_DATA_FORK;
383 	args->trans = tp;
384 	args->op_flags = XFS_DA_OP_OKNOENT;
385 	if (ci_name)
386 		args->op_flags |= XFS_DA_OP_CILOOKUP;
387 
388 	lock_mode = xfs_ilock_data_map_shared(dp);
389 	if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
390 		rval = xfs_dir2_sf_lookup(args);
391 		goto out_check_rval;
392 	}
393 
394 	rval = xfs_dir2_isblock(args, &v);
395 	if (rval)
396 		goto out_free;
397 	if (v) {
398 		rval = xfs_dir2_block_lookup(args);
399 		goto out_check_rval;
400 	}
401 
402 	rval = xfs_dir2_isleaf(args, &v);
403 	if (rval)
404 		goto out_free;
405 	if (v)
406 		rval = xfs_dir2_leaf_lookup(args);
407 	else
408 		rval = xfs_dir2_node_lookup(args);
409 
410 out_check_rval:
411 	if (rval == -EEXIST)
412 		rval = 0;
413 	if (!rval) {
414 		*inum = args->inumber;
415 		if (ci_name) {
416 			ci_name->name = args->value;
417 			ci_name->len = args->valuelen;
418 		}
419 	}
420 out_free:
421 	xfs_iunlock(dp, lock_mode);
422 	kmem_free(args);
423 	return rval;
424 }
425 
426 /*
427  * Remove an entry from a directory.
428  */
429 int
430 xfs_dir_removename(
431 	struct xfs_trans	*tp,
432 	struct xfs_inode	*dp,
433 	struct xfs_name		*name,
434 	xfs_ino_t		ino,
435 	xfs_extlen_t		total)		/* bmap's total block count */
436 {
437 	struct xfs_da_args	*args;
438 	int			rval;
439 	bool			v;
440 
441 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
442 	XFS_STATS_INC(dp->i_mount, xs_dir_remove);
443 
444 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
445 	if (!args)
446 		return -ENOMEM;
447 
448 	args->geo = dp->i_mount->m_dir_geo;
449 	args->name = name->name;
450 	args->namelen = name->len;
451 	args->filetype = name->type;
452 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
453 	args->inumber = ino;
454 	args->dp = dp;
455 	args->total = total;
456 	args->whichfork = XFS_DATA_FORK;
457 	args->trans = tp;
458 
459 	if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
460 		rval = xfs_dir2_sf_removename(args);
461 		goto out_free;
462 	}
463 
464 	rval = xfs_dir2_isblock(args, &v);
465 	if (rval)
466 		goto out_free;
467 	if (v) {
468 		rval = xfs_dir2_block_removename(args);
469 		goto out_free;
470 	}
471 
472 	rval = xfs_dir2_isleaf(args, &v);
473 	if (rval)
474 		goto out_free;
475 	if (v)
476 		rval = xfs_dir2_leaf_removename(args);
477 	else
478 		rval = xfs_dir2_node_removename(args);
479 out_free:
480 	kmem_free(args);
481 	return rval;
482 }
483 
484 /*
485  * Replace the inode number of a directory entry.
486  */
487 int
488 xfs_dir_replace(
489 	struct xfs_trans	*tp,
490 	struct xfs_inode	*dp,
491 	const struct xfs_name	*name,		/* name of entry to replace */
492 	xfs_ino_t		inum,		/* new inode number */
493 	xfs_extlen_t		total)		/* bmap's total block count */
494 {
495 	struct xfs_da_args	*args;
496 	int			rval;
497 	bool			v;
498 
499 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
500 
501 	rval = xfs_dir_ino_validate(tp->t_mountp, inum);
502 	if (rval)
503 		return rval;
504 
505 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
506 	if (!args)
507 		return -ENOMEM;
508 
509 	args->geo = dp->i_mount->m_dir_geo;
510 	args->name = name->name;
511 	args->namelen = name->len;
512 	args->filetype = name->type;
513 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
514 	args->inumber = inum;
515 	args->dp = dp;
516 	args->total = total;
517 	args->whichfork = XFS_DATA_FORK;
518 	args->trans = tp;
519 
520 	if (dp->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
521 		rval = xfs_dir2_sf_replace(args);
522 		goto out_free;
523 	}
524 
525 	rval = xfs_dir2_isblock(args, &v);
526 	if (rval)
527 		goto out_free;
528 	if (v) {
529 		rval = xfs_dir2_block_replace(args);
530 		goto out_free;
531 	}
532 
533 	rval = xfs_dir2_isleaf(args, &v);
534 	if (rval)
535 		goto out_free;
536 	if (v)
537 		rval = xfs_dir2_leaf_replace(args);
538 	else
539 		rval = xfs_dir2_node_replace(args);
540 out_free:
541 	kmem_free(args);
542 	return rval;
543 }
544 
545 /*
546  * See if this entry can be added to the directory without allocating space.
547  */
548 int
549 xfs_dir_canenter(
550 	xfs_trans_t	*tp,
551 	xfs_inode_t	*dp,
552 	struct xfs_name	*name)		/* name of entry to add */
553 {
554 	return xfs_dir_createname(tp, dp, name, 0, 0);
555 }
556 
557 /*
558  * Utility routines.
559  */
560 
561 /*
562  * Add a block to the directory.
563  *
564  * This routine is for data and free blocks, not leaf/node blocks which are
565  * handled by xfs_da_grow_inode.
566  */
567 int
568 xfs_dir2_grow_inode(
569 	struct xfs_da_args	*args,
570 	int			space,	/* v2 dir's space XFS_DIR2_xxx_SPACE */
571 	xfs_dir2_db_t		*dbp)	/* out: block number added */
572 {
573 	struct xfs_inode	*dp = args->dp;
574 	struct xfs_mount	*mp = dp->i_mount;
575 	xfs_fileoff_t		bno;	/* directory offset of new block */
576 	int			count;	/* count of filesystem blocks */
577 	int			error;
578 
579 	trace_xfs_dir2_grow_inode(args, space);
580 
581 	/*
582 	 * Set lowest possible block in the space requested.
583 	 */
584 	bno = XFS_B_TO_FSBT(mp, space * XFS_DIR2_SPACE_SIZE);
585 	count = args->geo->fsbcount;
586 
587 	error = xfs_da_grow_inode_int(args, &bno, count);
588 	if (error)
589 		return error;
590 
591 	*dbp = xfs_dir2_da_to_db(args->geo, (xfs_dablk_t)bno);
592 
593 	/*
594 	 * Update file's size if this is the data space and it grew.
595 	 */
596 	if (space == XFS_DIR2_DATA_SPACE) {
597 		xfs_fsize_t	size;		/* directory file (data) size */
598 
599 		size = XFS_FSB_TO_B(mp, bno + count);
600 		if (size > dp->i_disk_size) {
601 			dp->i_disk_size = size;
602 			xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
603 		}
604 	}
605 	return 0;
606 }
607 
608 /*
609  * See if the directory is a single-block form directory.
610  */
611 int
612 xfs_dir2_isblock(
613 	struct xfs_da_args	*args,
614 	bool			*isblock)
615 {
616 	struct xfs_mount	*mp = args->dp->i_mount;
617 	xfs_fileoff_t		eof;
618 	int			error;
619 
620 	error = xfs_bmap_last_offset(args->dp, &eof, XFS_DATA_FORK);
621 	if (error)
622 		return error;
623 
624 	*isblock = false;
625 	if (XFS_FSB_TO_B(mp, eof) != args->geo->blksize)
626 		return 0;
627 
628 	*isblock = true;
629 	if (XFS_IS_CORRUPT(mp, args->dp->i_disk_size != args->geo->blksize))
630 		return -EFSCORRUPTED;
631 	return 0;
632 }
633 
634 /*
635  * See if the directory is a single-leaf form directory.
636  */
637 int
638 xfs_dir2_isleaf(
639 	struct xfs_da_args	*args,
640 	bool			*isleaf)
641 {
642 	xfs_fileoff_t		eof;
643 	int			error;
644 
645 	error = xfs_bmap_last_offset(args->dp, &eof, XFS_DATA_FORK);
646 	if (error)
647 		return error;
648 
649 	*isleaf = false;
650 	if (eof != args->geo->leafblk + args->geo->fsbcount)
651 		return 0;
652 
653 	*isleaf = true;
654 	return 0;
655 }
656 
657 /*
658  * Remove the given block from the directory.
659  * This routine is used for data and free blocks, leaf/node are done
660  * by xfs_da_shrink_inode.
661  */
662 int
663 xfs_dir2_shrink_inode(
664 	struct xfs_da_args	*args,
665 	xfs_dir2_db_t		db,
666 	struct xfs_buf		*bp)
667 {
668 	xfs_fileoff_t		bno;		/* directory file offset */
669 	xfs_dablk_t		da;		/* directory file offset */
670 	int			done;		/* bunmap is finished */
671 	struct xfs_inode	*dp;
672 	int			error;
673 	struct xfs_mount	*mp;
674 	struct xfs_trans	*tp;
675 
676 	trace_xfs_dir2_shrink_inode(args, db);
677 
678 	dp = args->dp;
679 	mp = dp->i_mount;
680 	tp = args->trans;
681 	da = xfs_dir2_db_to_da(args->geo, db);
682 
683 	/* Unmap the fsblock(s). */
684 	error = xfs_bunmapi(tp, dp, da, args->geo->fsbcount, 0, 0, &done);
685 	if (error) {
686 		/*
687 		 * ENOSPC actually can happen if we're in a removename with no
688 		 * space reservation, and the resulting block removal would
689 		 * cause a bmap btree split or conversion from extents to btree.
690 		 * This can only happen for un-fragmented directory blocks,
691 		 * since you need to be punching out the middle of an extent.
692 		 * In this case we need to leave the block in the file, and not
693 		 * binval it.  So the block has to be in a consistent empty
694 		 * state and appropriately logged.  We don't free up the buffer,
695 		 * the caller can tell it hasn't happened since it got an error
696 		 * back.
697 		 */
698 		return error;
699 	}
700 	ASSERT(done);
701 	/*
702 	 * Invalidate the buffer from the transaction.
703 	 */
704 	xfs_trans_binval(tp, bp);
705 	/*
706 	 * If it's not a data block, we're done.
707 	 */
708 	if (db >= xfs_dir2_byte_to_db(args->geo, XFS_DIR2_LEAF_OFFSET))
709 		return 0;
710 	/*
711 	 * If the block isn't the last one in the directory, we're done.
712 	 */
713 	if (dp->i_disk_size > xfs_dir2_db_off_to_byte(args->geo, db + 1, 0))
714 		return 0;
715 	bno = da;
716 	if ((error = xfs_bmap_last_before(tp, dp, &bno, XFS_DATA_FORK))) {
717 		/*
718 		 * This can't really happen unless there's kernel corruption.
719 		 */
720 		return error;
721 	}
722 	if (db == args->geo->datablk)
723 		ASSERT(bno == 0);
724 	else
725 		ASSERT(bno > 0);
726 	/*
727 	 * Set the size to the new last block.
728 	 */
729 	dp->i_disk_size = XFS_FSB_TO_B(mp, bno);
730 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
731 	return 0;
732 }
733 
734 /* Returns true if the directory entry name is valid. */
735 bool
736 xfs_dir2_namecheck(
737 	const void	*name,
738 	size_t		length)
739 {
740 	/*
741 	 * MAXNAMELEN includes the trailing null, but (name/length) leave it
742 	 * out, so use >= for the length check.
743 	 */
744 	if (length >= MAXNAMELEN)
745 		return false;
746 
747 	/* There shouldn't be any slashes or nulls here */
748 	return !memchr(name, '/', length) && !memchr(name, 0, length);
749 }
750 
751 xfs_dahash_t
752 xfs_dir2_hashname(
753 	struct xfs_mount	*mp,
754 	const struct xfs_name	*name)
755 {
756 	if (unlikely(xfs_has_asciici(mp)))
757 		return xfs_ascii_ci_hashname(name);
758 	return xfs_da_hashname(name->name, name->len);
759 }
760 
761 enum xfs_dacmp
762 xfs_dir2_compname(
763 	struct xfs_da_args	*args,
764 	const unsigned char	*name,
765 	int			len)
766 {
767 	if (unlikely(xfs_has_asciici(args->dp->i_mount)))
768 		return xfs_ascii_ci_compname(args, name, len);
769 	return xfs_da_compname(args, name, len);
770 }
771