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