xref: /linux/fs/xfs/libxfs/xfs_dir2.c (revision d198b34f3855eee2571dda03eea75a09c7c31480)
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 struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2, XFS_DIR3_FT_DIR };
23 
24 /*
25  * Convert inode mode to directory entry filetype
26  */
27 unsigned char
28 xfs_mode_to_ftype(
29 	int		mode)
30 {
31 	switch (mode & S_IFMT) {
32 	case S_IFREG:
33 		return XFS_DIR3_FT_REG_FILE;
34 	case S_IFDIR:
35 		return XFS_DIR3_FT_DIR;
36 	case S_IFCHR:
37 		return XFS_DIR3_FT_CHRDEV;
38 	case S_IFBLK:
39 		return XFS_DIR3_FT_BLKDEV;
40 	case S_IFIFO:
41 		return XFS_DIR3_FT_FIFO;
42 	case S_IFSOCK:
43 		return XFS_DIR3_FT_SOCK;
44 	case S_IFLNK:
45 		return XFS_DIR3_FT_SYMLINK;
46 	default:
47 		return XFS_DIR3_FT_UNKNOWN;
48 	}
49 }
50 
51 /*
52  * ASCII case-insensitive (ie. A-Z) support for directories that was
53  * used in IRIX.
54  */
55 xfs_dahash_t
56 xfs_ascii_ci_hashname(
57 	struct xfs_name	*name)
58 {
59 	xfs_dahash_t	hash;
60 	int		i;
61 
62 	for (i = 0, hash = 0; i < name->len; i++)
63 		hash = tolower(name->name[i]) ^ rol32(hash, 7);
64 
65 	return hash;
66 }
67 
68 enum xfs_dacmp
69 xfs_ascii_ci_compname(
70 	struct xfs_da_args	*args,
71 	const unsigned char	*name,
72 	int			len)
73 {
74 	enum xfs_dacmp		result;
75 	int			i;
76 
77 	if (args->namelen != len)
78 		return XFS_CMP_DIFFERENT;
79 
80 	result = XFS_CMP_EXACT;
81 	for (i = 0; i < len; i++) {
82 		if (args->name[i] == name[i])
83 			continue;
84 		if (tolower(args->name[i]) != tolower(name[i]))
85 			return XFS_CMP_DIFFERENT;
86 		result = XFS_CMP_CASE;
87 	}
88 
89 	return result;
90 }
91 
92 int
93 xfs_da_mount(
94 	struct xfs_mount	*mp)
95 {
96 	struct xfs_da_geometry	*dageo;
97 
98 
99 	ASSERT(mp->m_sb.sb_versionnum & XFS_SB_VERSION_DIRV2BIT);
100 	ASSERT(xfs_dir2_dirblock_bytes(&mp->m_sb) <= XFS_MAX_BLOCKSIZE);
101 
102 	mp->m_dir_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
103 				    KM_MAYFAIL);
104 	mp->m_attr_geo = kmem_zalloc(sizeof(struct xfs_da_geometry),
105 				     KM_MAYFAIL);
106 	if (!mp->m_dir_geo || !mp->m_attr_geo) {
107 		kmem_free(mp->m_dir_geo);
108 		kmem_free(mp->m_attr_geo);
109 		return -ENOMEM;
110 	}
111 
112 	/* set up directory geometry */
113 	dageo = mp->m_dir_geo;
114 	dageo->blklog = mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog;
115 	dageo->fsblog = mp->m_sb.sb_blocklog;
116 	dageo->blksize = xfs_dir2_dirblock_bytes(&mp->m_sb);
117 	dageo->fsbcount = 1 << mp->m_sb.sb_dirblklog;
118 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
119 		dageo->node_hdr_size = sizeof(struct xfs_da3_node_hdr);
120 		dageo->leaf_hdr_size = sizeof(struct xfs_dir3_leaf_hdr);
121 		dageo->free_hdr_size = sizeof(struct xfs_dir3_free_hdr);
122 		dageo->data_entry_offset =
123 				sizeof(struct xfs_dir3_data_hdr);
124 	} else {
125 		dageo->node_hdr_size = sizeof(struct xfs_da_node_hdr);
126 		dageo->leaf_hdr_size = sizeof(struct xfs_dir2_leaf_hdr);
127 		dageo->free_hdr_size = sizeof(struct xfs_dir2_free_hdr);
128 		dageo->data_entry_offset =
129 				sizeof(struct xfs_dir2_data_hdr);
130 	}
131 	dageo->leaf_max_ents = (dageo->blksize - dageo->leaf_hdr_size) /
132 			sizeof(struct xfs_dir2_leaf_entry);
133 	dageo->free_max_bests = (dageo->blksize - dageo->free_hdr_size) /
134 			sizeof(xfs_dir2_data_off_t);
135 
136 	dageo->data_first_offset = dageo->data_entry_offset +
137 			xfs_dir2_data_entsize(mp, 1) +
138 			xfs_dir2_data_entsize(mp, 2);
139 
140 	/*
141 	 * Now we've set up the block conversion variables, we can calculate the
142 	 * segment block constants using the geometry structure.
143 	 */
144 	dageo->datablk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_DATA_OFFSET);
145 	dageo->leafblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_LEAF_OFFSET);
146 	dageo->freeblk = xfs_dir2_byte_to_da(dageo, XFS_DIR2_FREE_OFFSET);
147 	dageo->node_ents = (dageo->blksize - dageo->node_hdr_size) /
148 				(uint)sizeof(xfs_da_node_entry_t);
149 	dageo->magicpct = (dageo->blksize * 37) / 100;
150 
151 	/* set up attribute geometry - single fsb only */
152 	dageo = mp->m_attr_geo;
153 	dageo->blklog = mp->m_sb.sb_blocklog;
154 	dageo->fsblog = mp->m_sb.sb_blocklog;
155 	dageo->blksize = 1 << dageo->blklog;
156 	dageo->fsbcount = 1;
157 	dageo->node_hdr_size = mp->m_dir_geo->node_hdr_size;
158 	dageo->node_ents = (dageo->blksize - dageo->node_hdr_size) /
159 				(uint)sizeof(xfs_da_node_entry_t);
160 	dageo->magicpct = (dageo->blksize * 37) / 100;
161 	return 0;
162 }
163 
164 void
165 xfs_da_unmount(
166 	struct xfs_mount	*mp)
167 {
168 	kmem_free(mp->m_dir_geo);
169 	kmem_free(mp->m_attr_geo);
170 }
171 
172 /*
173  * Return 1 if directory contains only "." and "..".
174  */
175 int
176 xfs_dir_isempty(
177 	xfs_inode_t	*dp)
178 {
179 	xfs_dir2_sf_hdr_t	*sfp;
180 
181 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
182 	if (dp->i_d.di_size == 0)	/* might happen during shutdown. */
183 		return 1;
184 	if (dp->i_d.di_size > XFS_IFORK_DSIZE(dp))
185 		return 0;
186 	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
187 	return !sfp->count;
188 }
189 
190 /*
191  * Validate a given inode number.
192  */
193 int
194 xfs_dir_ino_validate(
195 	xfs_mount_t	*mp,
196 	xfs_ino_t	ino)
197 {
198 	bool		ino_ok = xfs_verify_dir_ino(mp, ino);
199 
200 	if (XFS_IS_CORRUPT(mp, !ino_ok) ||
201 	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_DIR_INO_VALIDATE)) {
202 		xfs_warn(mp, "Invalid inode number 0x%Lx",
203 				(unsigned long long) ino);
204 		return -EFSCORRUPTED;
205 	}
206 	return 0;
207 }
208 
209 /*
210  * Initialize a directory with its "." and ".." entries.
211  */
212 int
213 xfs_dir_init(
214 	xfs_trans_t	*tp,
215 	xfs_inode_t	*dp,
216 	xfs_inode_t	*pdp)
217 {
218 	struct xfs_da_args *args;
219 	int		error;
220 
221 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
222 	error = xfs_dir_ino_validate(tp->t_mountp, pdp->i_ino);
223 	if (error)
224 		return error;
225 
226 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
227 	if (!args)
228 		return -ENOMEM;
229 
230 	args->geo = dp->i_mount->m_dir_geo;
231 	args->dp = dp;
232 	args->trans = tp;
233 	error = xfs_dir2_sf_create(args, pdp->i_ino);
234 	kmem_free(args);
235 	return error;
236 }
237 
238 /*
239  * Enter a name in a directory, or check for available space.
240  * If inum is 0, only the available space test is performed.
241  */
242 int
243 xfs_dir_createname(
244 	struct xfs_trans	*tp,
245 	struct xfs_inode	*dp,
246 	struct xfs_name		*name,
247 	xfs_ino_t		inum,		/* new entry inode number */
248 	xfs_extlen_t		total)		/* bmap's total block count */
249 {
250 	struct xfs_da_args	*args;
251 	int			rval;
252 	int			v;		/* type-checking value */
253 
254 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
255 
256 	if (inum) {
257 		rval = xfs_dir_ino_validate(tp->t_mountp, inum);
258 		if (rval)
259 			return rval;
260 		XFS_STATS_INC(dp->i_mount, xs_dir_create);
261 	}
262 
263 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
264 	if (!args)
265 		return -ENOMEM;
266 
267 	args->geo = dp->i_mount->m_dir_geo;
268 	args->name = name->name;
269 	args->namelen = name->len;
270 	args->filetype = name->type;
271 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
272 	args->inumber = inum;
273 	args->dp = dp;
274 	args->total = total;
275 	args->whichfork = XFS_DATA_FORK;
276 	args->trans = tp;
277 	args->op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
278 	if (!inum)
279 		args->op_flags |= XFS_DA_OP_JUSTCHECK;
280 
281 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
282 		rval = xfs_dir2_sf_addname(args);
283 		goto out_free;
284 	}
285 
286 	rval = xfs_dir2_isblock(args, &v);
287 	if (rval)
288 		goto out_free;
289 	if (v) {
290 		rval = xfs_dir2_block_addname(args);
291 		goto out_free;
292 	}
293 
294 	rval = xfs_dir2_isleaf(args, &v);
295 	if (rval)
296 		goto out_free;
297 	if (v)
298 		rval = xfs_dir2_leaf_addname(args);
299 	else
300 		rval = xfs_dir2_node_addname(args);
301 
302 out_free:
303 	kmem_free(args);
304 	return rval;
305 }
306 
307 /*
308  * If doing a CI lookup and case-insensitive match, dup actual name into
309  * args.value. Return EEXIST for success (ie. name found) or an error.
310  */
311 int
312 xfs_dir_cilookup_result(
313 	struct xfs_da_args *args,
314 	const unsigned char *name,
315 	int		len)
316 {
317 	if (args->cmpresult == XFS_CMP_DIFFERENT)
318 		return -ENOENT;
319 	if (args->cmpresult != XFS_CMP_CASE ||
320 					!(args->op_flags & XFS_DA_OP_CILOOKUP))
321 		return -EEXIST;
322 
323 	args->value = kmem_alloc(len, KM_NOFS | KM_MAYFAIL);
324 	if (!args->value)
325 		return -ENOMEM;
326 
327 	memcpy(args->value, name, len);
328 	args->valuelen = len;
329 	return -EEXIST;
330 }
331 
332 /*
333  * Lookup a name in a directory, give back the inode number.
334  * If ci_name is not NULL, returns the actual name in ci_name if it differs
335  * to name, or ci_name->name is set to NULL for an exact match.
336  */
337 
338 int
339 xfs_dir_lookup(
340 	xfs_trans_t	*tp,
341 	xfs_inode_t	*dp,
342 	struct xfs_name	*name,
343 	xfs_ino_t	*inum,		/* out: inode number */
344 	struct xfs_name *ci_name)	/* out: actual name if CI match */
345 {
346 	struct xfs_da_args *args;
347 	int		rval;
348 	int		v;		/* type-checking value */
349 	int		lock_mode;
350 
351 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
352 	XFS_STATS_INC(dp->i_mount, xs_dir_lookup);
353 
354 	/*
355 	 * We need to use KM_NOFS here so that lockdep will not throw false
356 	 * positive deadlock warnings on a non-transactional lookup path. It is
357 	 * safe to recurse into inode recalim in that case, but lockdep can't
358 	 * easily be taught about it. Hence KM_NOFS avoids having to add more
359 	 * lockdep Doing this avoids having to add a bunch of lockdep class
360 	 * annotations into the reclaim path for the ilock.
361 	 */
362 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
363 	args->geo = dp->i_mount->m_dir_geo;
364 	args->name = name->name;
365 	args->namelen = name->len;
366 	args->filetype = name->type;
367 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
368 	args->dp = dp;
369 	args->whichfork = XFS_DATA_FORK;
370 	args->trans = tp;
371 	args->op_flags = XFS_DA_OP_OKNOENT;
372 	if (ci_name)
373 		args->op_flags |= XFS_DA_OP_CILOOKUP;
374 
375 	lock_mode = xfs_ilock_data_map_shared(dp);
376 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
377 		rval = xfs_dir2_sf_lookup(args);
378 		goto out_check_rval;
379 	}
380 
381 	rval = xfs_dir2_isblock(args, &v);
382 	if (rval)
383 		goto out_free;
384 	if (v) {
385 		rval = xfs_dir2_block_lookup(args);
386 		goto out_check_rval;
387 	}
388 
389 	rval = xfs_dir2_isleaf(args, &v);
390 	if (rval)
391 		goto out_free;
392 	if (v)
393 		rval = xfs_dir2_leaf_lookup(args);
394 	else
395 		rval = xfs_dir2_node_lookup(args);
396 
397 out_check_rval:
398 	if (rval == -EEXIST)
399 		rval = 0;
400 	if (!rval) {
401 		*inum = args->inumber;
402 		if (ci_name) {
403 			ci_name->name = args->value;
404 			ci_name->len = args->valuelen;
405 		}
406 	}
407 out_free:
408 	xfs_iunlock(dp, lock_mode);
409 	kmem_free(args);
410 	return rval;
411 }
412 
413 /*
414  * Remove an entry from a directory.
415  */
416 int
417 xfs_dir_removename(
418 	struct xfs_trans	*tp,
419 	struct xfs_inode	*dp,
420 	struct xfs_name		*name,
421 	xfs_ino_t		ino,
422 	xfs_extlen_t		total)		/* bmap's total block count */
423 {
424 	struct xfs_da_args	*args;
425 	int			rval;
426 	int			v;		/* type-checking value */
427 
428 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
429 	XFS_STATS_INC(dp->i_mount, xs_dir_remove);
430 
431 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
432 	if (!args)
433 		return -ENOMEM;
434 
435 	args->geo = dp->i_mount->m_dir_geo;
436 	args->name = name->name;
437 	args->namelen = name->len;
438 	args->filetype = name->type;
439 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
440 	args->inumber = ino;
441 	args->dp = dp;
442 	args->total = total;
443 	args->whichfork = XFS_DATA_FORK;
444 	args->trans = tp;
445 
446 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
447 		rval = xfs_dir2_sf_removename(args);
448 		goto out_free;
449 	}
450 
451 	rval = xfs_dir2_isblock(args, &v);
452 	if (rval)
453 		goto out_free;
454 	if (v) {
455 		rval = xfs_dir2_block_removename(args);
456 		goto out_free;
457 	}
458 
459 	rval = xfs_dir2_isleaf(args, &v);
460 	if (rval)
461 		goto out_free;
462 	if (v)
463 		rval = xfs_dir2_leaf_removename(args);
464 	else
465 		rval = xfs_dir2_node_removename(args);
466 out_free:
467 	kmem_free(args);
468 	return rval;
469 }
470 
471 /*
472  * Replace the inode number of a directory entry.
473  */
474 int
475 xfs_dir_replace(
476 	struct xfs_trans	*tp,
477 	struct xfs_inode	*dp,
478 	struct xfs_name		*name,		/* name of entry to replace */
479 	xfs_ino_t		inum,		/* new inode number */
480 	xfs_extlen_t		total)		/* bmap's total block count */
481 {
482 	struct xfs_da_args	*args;
483 	int			rval;
484 	int			v;		/* type-checking value */
485 
486 	ASSERT(S_ISDIR(VFS_I(dp)->i_mode));
487 
488 	rval = xfs_dir_ino_validate(tp->t_mountp, inum);
489 	if (rval)
490 		return rval;
491 
492 	args = kmem_zalloc(sizeof(*args), KM_NOFS);
493 	if (!args)
494 		return -ENOMEM;
495 
496 	args->geo = dp->i_mount->m_dir_geo;
497 	args->name = name->name;
498 	args->namelen = name->len;
499 	args->filetype = name->type;
500 	args->hashval = xfs_dir2_hashname(dp->i_mount, name);
501 	args->inumber = inum;
502 	args->dp = dp;
503 	args->total = total;
504 	args->whichfork = XFS_DATA_FORK;
505 	args->trans = tp;
506 
507 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
508 		rval = xfs_dir2_sf_replace(args);
509 		goto out_free;
510 	}
511 
512 	rval = xfs_dir2_isblock(args, &v);
513 	if (rval)
514 		goto out_free;
515 	if (v) {
516 		rval = xfs_dir2_block_replace(args);
517 		goto out_free;
518 	}
519 
520 	rval = xfs_dir2_isleaf(args, &v);
521 	if (rval)
522 		goto out_free;
523 	if (v)
524 		rval = xfs_dir2_leaf_replace(args);
525 	else
526 		rval = xfs_dir2_node_replace(args);
527 out_free:
528 	kmem_free(args);
529 	return rval;
530 }
531 
532 /*
533  * See if this entry can be added to the directory without allocating space.
534  */
535 int
536 xfs_dir_canenter(
537 	xfs_trans_t	*tp,
538 	xfs_inode_t	*dp,
539 	struct xfs_name	*name)		/* name of entry to add */
540 {
541 	return xfs_dir_createname(tp, dp, name, 0, 0);
542 }
543 
544 /*
545  * Utility routines.
546  */
547 
548 /*
549  * Add a block to the directory.
550  *
551  * This routine is for data and free blocks, not leaf/node blocks which are
552  * handled by xfs_da_grow_inode.
553  */
554 int
555 xfs_dir2_grow_inode(
556 	struct xfs_da_args	*args,
557 	int			space,	/* v2 dir's space XFS_DIR2_xxx_SPACE */
558 	xfs_dir2_db_t		*dbp)	/* out: block number added */
559 {
560 	struct xfs_inode	*dp = args->dp;
561 	struct xfs_mount	*mp = dp->i_mount;
562 	xfs_fileoff_t		bno;	/* directory offset of new block */
563 	int			count;	/* count of filesystem blocks */
564 	int			error;
565 
566 	trace_xfs_dir2_grow_inode(args, space);
567 
568 	/*
569 	 * Set lowest possible block in the space requested.
570 	 */
571 	bno = XFS_B_TO_FSBT(mp, space * XFS_DIR2_SPACE_SIZE);
572 	count = args->geo->fsbcount;
573 
574 	error = xfs_da_grow_inode_int(args, &bno, count);
575 	if (error)
576 		return error;
577 
578 	*dbp = xfs_dir2_da_to_db(args->geo, (xfs_dablk_t)bno);
579 
580 	/*
581 	 * Update file's size if this is the data space and it grew.
582 	 */
583 	if (space == XFS_DIR2_DATA_SPACE) {
584 		xfs_fsize_t	size;		/* directory file (data) size */
585 
586 		size = XFS_FSB_TO_B(mp, bno + count);
587 		if (size > dp->i_d.di_size) {
588 			dp->i_d.di_size = size;
589 			xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
590 		}
591 	}
592 	return 0;
593 }
594 
595 /*
596  * See if the directory is a single-block form directory.
597  */
598 int
599 xfs_dir2_isblock(
600 	struct xfs_da_args	*args,
601 	int			*vp)	/* out: 1 is block, 0 is not block */
602 {
603 	xfs_fileoff_t		last;	/* last file offset */
604 	int			rval;
605 
606 	if ((rval = xfs_bmap_last_offset(args->dp, &last, XFS_DATA_FORK)))
607 		return rval;
608 	rval = XFS_FSB_TO_B(args->dp->i_mount, last) == args->geo->blksize;
609 	if (XFS_IS_CORRUPT(args->dp->i_mount,
610 			   rval != 0 &&
611 			   args->dp->i_d.di_size != args->geo->blksize))
612 		return -EFSCORRUPTED;
613 	*vp = rval;
614 	return 0;
615 }
616 
617 /*
618  * See if the directory is a single-leaf form directory.
619  */
620 int
621 xfs_dir2_isleaf(
622 	struct xfs_da_args	*args,
623 	int			*vp)	/* out: 1 is block, 0 is not block */
624 {
625 	xfs_fileoff_t		last;	/* last file offset */
626 	int			rval;
627 
628 	if ((rval = xfs_bmap_last_offset(args->dp, &last, XFS_DATA_FORK)))
629 		return rval;
630 	*vp = last == args->geo->leafblk + args->geo->fsbcount;
631 	return 0;
632 }
633 
634 /*
635  * Remove the given block from the directory.
636  * This routine is used for data and free blocks, leaf/node are done
637  * by xfs_da_shrink_inode.
638  */
639 int
640 xfs_dir2_shrink_inode(
641 	struct xfs_da_args	*args,
642 	xfs_dir2_db_t		db,
643 	struct xfs_buf		*bp)
644 {
645 	xfs_fileoff_t		bno;		/* directory file offset */
646 	xfs_dablk_t		da;		/* directory file offset */
647 	int			done;		/* bunmap is finished */
648 	struct xfs_inode	*dp;
649 	int			error;
650 	struct xfs_mount	*mp;
651 	struct xfs_trans	*tp;
652 
653 	trace_xfs_dir2_shrink_inode(args, db);
654 
655 	dp = args->dp;
656 	mp = dp->i_mount;
657 	tp = args->trans;
658 	da = xfs_dir2_db_to_da(args->geo, db);
659 
660 	/* Unmap the fsblock(s). */
661 	error = xfs_bunmapi(tp, dp, da, args->geo->fsbcount, 0, 0, &done);
662 	if (error) {
663 		/*
664 		 * ENOSPC actually can happen if we're in a removename with no
665 		 * space reservation, and the resulting block removal would
666 		 * cause a bmap btree split or conversion from extents to btree.
667 		 * This can only happen for un-fragmented directory blocks,
668 		 * since you need to be punching out the middle of an extent.
669 		 * In this case we need to leave the block in the file, and not
670 		 * binval it.  So the block has to be in a consistent empty
671 		 * state and appropriately logged.  We don't free up the buffer,
672 		 * the caller can tell it hasn't happened since it got an error
673 		 * back.
674 		 */
675 		return error;
676 	}
677 	ASSERT(done);
678 	/*
679 	 * Invalidate the buffer from the transaction.
680 	 */
681 	xfs_trans_binval(tp, bp);
682 	/*
683 	 * If it's not a data block, we're done.
684 	 */
685 	if (db >= xfs_dir2_byte_to_db(args->geo, XFS_DIR2_LEAF_OFFSET))
686 		return 0;
687 	/*
688 	 * If the block isn't the last one in the directory, we're done.
689 	 */
690 	if (dp->i_d.di_size > xfs_dir2_db_off_to_byte(args->geo, db + 1, 0))
691 		return 0;
692 	bno = da;
693 	if ((error = xfs_bmap_last_before(tp, dp, &bno, XFS_DATA_FORK))) {
694 		/*
695 		 * This can't really happen unless there's kernel corruption.
696 		 */
697 		return error;
698 	}
699 	if (db == args->geo->datablk)
700 		ASSERT(bno == 0);
701 	else
702 		ASSERT(bno > 0);
703 	/*
704 	 * Set the size to the new last block.
705 	 */
706 	dp->i_d.di_size = XFS_FSB_TO_B(mp, bno);
707 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
708 	return 0;
709 }
710 
711 /* Returns true if the directory entry name is valid. */
712 bool
713 xfs_dir2_namecheck(
714 	const void	*name,
715 	size_t		length)
716 {
717 	/*
718 	 * MAXNAMELEN includes the trailing null, but (name/length) leave it
719 	 * out, so use >= for the length check.
720 	 */
721 	if (length >= MAXNAMELEN)
722 		return false;
723 
724 	/* There shouldn't be any slashes or nulls here */
725 	return !memchr(name, '/', length) && !memchr(name, 0, length);
726 }
727 
728 xfs_dahash_t
729 xfs_dir2_hashname(
730 	struct xfs_mount	*mp,
731 	struct xfs_name		*name)
732 {
733 	if (unlikely(xfs_sb_version_hasasciici(&mp->m_sb)))
734 		return xfs_ascii_ci_hashname(name);
735 	return xfs_da_hashname(name->name, name->len);
736 }
737 
738 enum xfs_dacmp
739 xfs_dir2_compname(
740 	struct xfs_da_args	*args,
741 	const unsigned char	*name,
742 	int			len)
743 {
744 	if (unlikely(xfs_sb_version_hasasciici(&args->dp->i_mount->m_sb)))
745 		return xfs_ascii_ci_compname(args, name, len);
746 	return xfs_da_compname(args, name, len);
747 }
748