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_types.h"
21 #include "xfs_bit.h"
22 #include "xfs_log.h"
23 #include "xfs_inum.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_mount.h"
28 #include "xfs_da_btree.h"
29 #include "xfs_bmap_btree.h"
30 #include "xfs_alloc_btree.h"
31 #include "xfs_dinode.h"
32 #include "xfs_inode.h"
33 #include "xfs_inode_item.h"
34 #include "xfs_bmap.h"
35 #include "xfs_dir2.h"
36 #include "xfs_dir2_format.h"
37 #include "xfs_dir2_priv.h"
38 #include "xfs_error.h"
39 #include "xfs_vnodeops.h"
40 #include "xfs_trace.h"
41 
42 struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2};
43 
44 /*
45  * ASCII case-insensitive (ie. A-Z) support for directories that was
46  * used in IRIX.
47  */
48 STATIC xfs_dahash_t
xfs_ascii_ci_hashname(struct xfs_name * name)49 xfs_ascii_ci_hashname(
50 	struct xfs_name	*name)
51 {
52 	xfs_dahash_t	hash;
53 	int		i;
54 
55 	for (i = 0, hash = 0; i < name->len; i++)
56 		hash = tolower(name->name[i]) ^ rol32(hash, 7);
57 
58 	return hash;
59 }
60 
61 STATIC enum xfs_dacmp
xfs_ascii_ci_compname(struct xfs_da_args * args,const unsigned char * name,int len)62 xfs_ascii_ci_compname(
63 	struct xfs_da_args *args,
64 	const unsigned char *name,
65 	int		len)
66 {
67 	enum xfs_dacmp	result;
68 	int		i;
69 
70 	if (args->namelen != len)
71 		return XFS_CMP_DIFFERENT;
72 
73 	result = XFS_CMP_EXACT;
74 	for (i = 0; i < len; i++) {
75 		if (args->name[i] == name[i])
76 			continue;
77 		if (tolower(args->name[i]) != tolower(name[i]))
78 			return XFS_CMP_DIFFERENT;
79 		result = XFS_CMP_CASE;
80 	}
81 
82 	return result;
83 }
84 
85 static struct xfs_nameops xfs_ascii_ci_nameops = {
86 	.hashname	= xfs_ascii_ci_hashname,
87 	.compname	= xfs_ascii_ci_compname,
88 };
89 
90 void
xfs_dir_mount(xfs_mount_t * mp)91 xfs_dir_mount(
92 	xfs_mount_t	*mp)
93 {
94 	ASSERT(xfs_sb_version_hasdirv2(&mp->m_sb));
95 	ASSERT((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) <=
96 	       XFS_MAX_BLOCKSIZE);
97 	mp->m_dirblksize = 1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog);
98 	mp->m_dirblkfsbs = 1 << mp->m_sb.sb_dirblklog;
99 	mp->m_dirdatablk = xfs_dir2_db_to_da(mp, XFS_DIR2_DATA_FIRSTDB(mp));
100 	mp->m_dirleafblk = xfs_dir2_db_to_da(mp, XFS_DIR2_LEAF_FIRSTDB(mp));
101 	mp->m_dirfreeblk = xfs_dir2_db_to_da(mp, XFS_DIR2_FREE_FIRSTDB(mp));
102 	mp->m_attr_node_ents =
103 		(mp->m_sb.sb_blocksize - (uint)sizeof(xfs_da_node_hdr_t)) /
104 		(uint)sizeof(xfs_da_node_entry_t);
105 	mp->m_dir_node_ents =
106 		(mp->m_dirblksize - (uint)sizeof(xfs_da_node_hdr_t)) /
107 		(uint)sizeof(xfs_da_node_entry_t);
108 	mp->m_dir_magicpct = (mp->m_dirblksize * 37) / 100;
109 	if (xfs_sb_version_hasasciici(&mp->m_sb))
110 		mp->m_dirnameops = &xfs_ascii_ci_nameops;
111 	else
112 		mp->m_dirnameops = &xfs_default_nameops;
113 }
114 
115 /*
116  * Return 1 if directory contains only "." and "..".
117  */
118 int
xfs_dir_isempty(xfs_inode_t * dp)119 xfs_dir_isempty(
120 	xfs_inode_t	*dp)
121 {
122 	xfs_dir2_sf_hdr_t	*sfp;
123 
124 	ASSERT(S_ISDIR(dp->i_d.di_mode));
125 	if (dp->i_d.di_size == 0)	/* might happen during shutdown. */
126 		return 1;
127 	if (dp->i_d.di_size > XFS_IFORK_DSIZE(dp))
128 		return 0;
129 	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
130 	return !sfp->count;
131 }
132 
133 /*
134  * Validate a given inode number.
135  */
136 int
xfs_dir_ino_validate(xfs_mount_t * mp,xfs_ino_t ino)137 xfs_dir_ino_validate(
138 	xfs_mount_t	*mp,
139 	xfs_ino_t	ino)
140 {
141 	xfs_agblock_t	agblkno;
142 	xfs_agino_t	agino;
143 	xfs_agnumber_t	agno;
144 	int		ino_ok;
145 	int		ioff;
146 
147 	agno = XFS_INO_TO_AGNO(mp, ino);
148 	agblkno = XFS_INO_TO_AGBNO(mp, ino);
149 	ioff = XFS_INO_TO_OFFSET(mp, ino);
150 	agino = XFS_OFFBNO_TO_AGINO(mp, agblkno, ioff);
151 	ino_ok =
152 		agno < mp->m_sb.sb_agcount &&
153 		agblkno < mp->m_sb.sb_agblocks &&
154 		agblkno != 0 &&
155 		ioff < (1 << mp->m_sb.sb_inopblog) &&
156 		XFS_AGINO_TO_INO(mp, agno, agino) == ino;
157 	if (unlikely(XFS_TEST_ERROR(!ino_ok, mp, XFS_ERRTAG_DIR_INO_VALIDATE,
158 			XFS_RANDOM_DIR_INO_VALIDATE))) {
159 		xfs_warn(mp, "Invalid inode number 0x%Lx",
160 				(unsigned long long) ino);
161 		XFS_ERROR_REPORT("xfs_dir_ino_validate", XFS_ERRLEVEL_LOW, mp);
162 		return XFS_ERROR(EFSCORRUPTED);
163 	}
164 	return 0;
165 }
166 
167 /*
168  * Initialize a directory with its "." and ".." entries.
169  */
170 int
xfs_dir_init(xfs_trans_t * tp,xfs_inode_t * dp,xfs_inode_t * pdp)171 xfs_dir_init(
172 	xfs_trans_t	*tp,
173 	xfs_inode_t	*dp,
174 	xfs_inode_t	*pdp)
175 {
176 	xfs_da_args_t	args;
177 	int		error;
178 
179 	memset((char *)&args, 0, sizeof(args));
180 	args.dp = dp;
181 	args.trans = tp;
182 	ASSERT(S_ISDIR(dp->i_d.di_mode));
183 	if ((error = xfs_dir_ino_validate(tp->t_mountp, pdp->i_ino)))
184 		return error;
185 	return xfs_dir2_sf_create(&args, pdp->i_ino);
186 }
187 
188 /*
189   Enter a name in a directory.
190  */
191 int
xfs_dir_createname(xfs_trans_t * tp,xfs_inode_t * dp,struct xfs_name * name,xfs_ino_t inum,xfs_fsblock_t * first,xfs_bmap_free_t * flist,xfs_extlen_t total)192 xfs_dir_createname(
193 	xfs_trans_t		*tp,
194 	xfs_inode_t		*dp,
195 	struct xfs_name		*name,
196 	xfs_ino_t		inum,		/* new entry inode number */
197 	xfs_fsblock_t		*first,		/* bmap's firstblock */
198 	xfs_bmap_free_t		*flist,		/* bmap's freeblock list */
199 	xfs_extlen_t		total)		/* bmap's total block count */
200 {
201 	xfs_da_args_t		args;
202 	int			rval;
203 	int			v;		/* type-checking value */
204 
205 	ASSERT(S_ISDIR(dp->i_d.di_mode));
206 	if ((rval = xfs_dir_ino_validate(tp->t_mountp, inum)))
207 		return rval;
208 	XFS_STATS_INC(xs_dir_create);
209 
210 	memset(&args, 0, sizeof(xfs_da_args_t));
211 	args.name = name->name;
212 	args.namelen = name->len;
213 	args.hashval = dp->i_mount->m_dirnameops->hashname(name);
214 	args.inumber = inum;
215 	args.dp = dp;
216 	args.firstblock = first;
217 	args.flist = flist;
218 	args.total = total;
219 	args.whichfork = XFS_DATA_FORK;
220 	args.trans = tp;
221 	args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
222 
223 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
224 		rval = xfs_dir2_sf_addname(&args);
225 	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
226 		return rval;
227 	else if (v)
228 		rval = xfs_dir2_block_addname(&args);
229 	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
230 		return rval;
231 	else if (v)
232 		rval = xfs_dir2_leaf_addname(&args);
233 	else
234 		rval = xfs_dir2_node_addname(&args);
235 	return rval;
236 }
237 
238 /*
239  * If doing a CI lookup and case-insensitive match, dup actual name into
240  * args.value. Return EEXIST for success (ie. name found) or an error.
241  */
242 int
xfs_dir_cilookup_result(struct xfs_da_args * args,const unsigned char * name,int len)243 xfs_dir_cilookup_result(
244 	struct xfs_da_args *args,
245 	const unsigned char *name,
246 	int		len)
247 {
248 	if (args->cmpresult == XFS_CMP_DIFFERENT)
249 		return ENOENT;
250 	if (args->cmpresult != XFS_CMP_CASE ||
251 					!(args->op_flags & XFS_DA_OP_CILOOKUP))
252 		return EEXIST;
253 
254 	args->value = kmem_alloc(len, KM_NOFS | KM_MAYFAIL);
255 	if (!args->value)
256 		return ENOMEM;
257 
258 	memcpy(args->value, name, len);
259 	args->valuelen = len;
260 	return EEXIST;
261 }
262 
263 /*
264  * Lookup a name in a directory, give back the inode number.
265  * If ci_name is not NULL, returns the actual name in ci_name if it differs
266  * to name, or ci_name->name is set to NULL for an exact match.
267  */
268 
269 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)270 xfs_dir_lookup(
271 	xfs_trans_t	*tp,
272 	xfs_inode_t	*dp,
273 	struct xfs_name	*name,
274 	xfs_ino_t	*inum,		/* out: inode number */
275 	struct xfs_name *ci_name)	/* out: actual name if CI match */
276 {
277 	xfs_da_args_t	args;
278 	int		rval;
279 	int		v;		/* type-checking value */
280 
281 	ASSERT(S_ISDIR(dp->i_d.di_mode));
282 	XFS_STATS_INC(xs_dir_lookup);
283 
284 	memset(&args, 0, sizeof(xfs_da_args_t));
285 	args.name = name->name;
286 	args.namelen = name->len;
287 	args.hashval = dp->i_mount->m_dirnameops->hashname(name);
288 	args.dp = dp;
289 	args.whichfork = XFS_DATA_FORK;
290 	args.trans = tp;
291 	args.op_flags = XFS_DA_OP_OKNOENT;
292 	if (ci_name)
293 		args.op_flags |= XFS_DA_OP_CILOOKUP;
294 
295 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
296 		rval = xfs_dir2_sf_lookup(&args);
297 	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
298 		return rval;
299 	else if (v)
300 		rval = xfs_dir2_block_lookup(&args);
301 	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
302 		return rval;
303 	else if (v)
304 		rval = xfs_dir2_leaf_lookup(&args);
305 	else
306 		rval = xfs_dir2_node_lookup(&args);
307 	if (rval == EEXIST)
308 		rval = 0;
309 	if (!rval) {
310 		*inum = args.inumber;
311 		if (ci_name) {
312 			ci_name->name = args.value;
313 			ci_name->len = args.valuelen;
314 		}
315 	}
316 	return rval;
317 }
318 
319 /*
320  * Remove an entry from a directory.
321  */
322 int
xfs_dir_removename(xfs_trans_t * tp,xfs_inode_t * dp,struct xfs_name * name,xfs_ino_t ino,xfs_fsblock_t * first,xfs_bmap_free_t * flist,xfs_extlen_t total)323 xfs_dir_removename(
324 	xfs_trans_t	*tp,
325 	xfs_inode_t	*dp,
326 	struct xfs_name	*name,
327 	xfs_ino_t	ino,
328 	xfs_fsblock_t	*first,		/* bmap's firstblock */
329 	xfs_bmap_free_t	*flist,		/* bmap's freeblock list */
330 	xfs_extlen_t	total)		/* bmap's total block count */
331 {
332 	xfs_da_args_t	args;
333 	int		rval;
334 	int		v;		/* type-checking value */
335 
336 	ASSERT(S_ISDIR(dp->i_d.di_mode));
337 	XFS_STATS_INC(xs_dir_remove);
338 
339 	memset(&args, 0, sizeof(xfs_da_args_t));
340 	args.name = name->name;
341 	args.namelen = name->len;
342 	args.hashval = dp->i_mount->m_dirnameops->hashname(name);
343 	args.inumber = ino;
344 	args.dp = dp;
345 	args.firstblock = first;
346 	args.flist = flist;
347 	args.total = total;
348 	args.whichfork = XFS_DATA_FORK;
349 	args.trans = tp;
350 
351 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
352 		rval = xfs_dir2_sf_removename(&args);
353 	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
354 		return rval;
355 	else if (v)
356 		rval = xfs_dir2_block_removename(&args);
357 	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
358 		return rval;
359 	else if (v)
360 		rval = xfs_dir2_leaf_removename(&args);
361 	else
362 		rval = xfs_dir2_node_removename(&args);
363 	return rval;
364 }
365 
366 /*
367  * Read a directory.
368  */
369 int
xfs_readdir(xfs_inode_t * dp,void * dirent,size_t bufsize,xfs_off_t * offset,filldir_t filldir)370 xfs_readdir(
371 	xfs_inode_t	*dp,
372 	void		*dirent,
373 	size_t		bufsize,
374 	xfs_off_t	*offset,
375 	filldir_t	filldir)
376 {
377 	int		rval;		/* return value */
378 	int		v;		/* type-checking value */
379 
380 	trace_xfs_readdir(dp);
381 
382 	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
383 		return XFS_ERROR(EIO);
384 
385 	ASSERT(S_ISDIR(dp->i_d.di_mode));
386 	XFS_STATS_INC(xs_dir_getdents);
387 
388 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
389 		rval = xfs_dir2_sf_getdents(dp, dirent, offset, filldir);
390 	else if ((rval = xfs_dir2_isblock(NULL, dp, &v)))
391 		;
392 	else if (v)
393 		rval = xfs_dir2_block_getdents(dp, dirent, offset, filldir);
394 	else
395 		rval = xfs_dir2_leaf_getdents(dp, dirent, bufsize, offset,
396 					      filldir);
397 	return rval;
398 }
399 
400 /*
401  * Replace the inode number of a directory entry.
402  */
403 int
xfs_dir_replace(xfs_trans_t * tp,xfs_inode_t * dp,struct xfs_name * name,xfs_ino_t inum,xfs_fsblock_t * first,xfs_bmap_free_t * flist,xfs_extlen_t total)404 xfs_dir_replace(
405 	xfs_trans_t	*tp,
406 	xfs_inode_t	*dp,
407 	struct xfs_name	*name,		/* name of entry to replace */
408 	xfs_ino_t	inum,		/* new inode number */
409 	xfs_fsblock_t	*first,		/* bmap's firstblock */
410 	xfs_bmap_free_t	*flist,		/* bmap's freeblock list */
411 	xfs_extlen_t	total)		/* bmap's total block count */
412 {
413 	xfs_da_args_t	args;
414 	int		rval;
415 	int		v;		/* type-checking value */
416 
417 	ASSERT(S_ISDIR(dp->i_d.di_mode));
418 
419 	if ((rval = xfs_dir_ino_validate(tp->t_mountp, inum)))
420 		return rval;
421 
422 	memset(&args, 0, sizeof(xfs_da_args_t));
423 	args.name = name->name;
424 	args.namelen = name->len;
425 	args.hashval = dp->i_mount->m_dirnameops->hashname(name);
426 	args.inumber = inum;
427 	args.dp = dp;
428 	args.firstblock = first;
429 	args.flist = flist;
430 	args.total = total;
431 	args.whichfork = XFS_DATA_FORK;
432 	args.trans = tp;
433 
434 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
435 		rval = xfs_dir2_sf_replace(&args);
436 	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
437 		return rval;
438 	else if (v)
439 		rval = xfs_dir2_block_replace(&args);
440 	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
441 		return rval;
442 	else if (v)
443 		rval = xfs_dir2_leaf_replace(&args);
444 	else
445 		rval = xfs_dir2_node_replace(&args);
446 	return rval;
447 }
448 
449 /*
450  * See if this entry can be added to the directory without allocating space.
451  * First checks that the caller couldn't reserve enough space (resblks = 0).
452  */
453 int
xfs_dir_canenter(xfs_trans_t * tp,xfs_inode_t * dp,struct xfs_name * name,uint resblks)454 xfs_dir_canenter(
455 	xfs_trans_t	*tp,
456 	xfs_inode_t	*dp,
457 	struct xfs_name	*name,		/* name of entry to add */
458 	uint		resblks)
459 {
460 	xfs_da_args_t	args;
461 	int		rval;
462 	int		v;		/* type-checking value */
463 
464 	if (resblks)
465 		return 0;
466 
467 	ASSERT(S_ISDIR(dp->i_d.di_mode));
468 
469 	memset(&args, 0, sizeof(xfs_da_args_t));
470 	args.name = name->name;
471 	args.namelen = name->len;
472 	args.hashval = dp->i_mount->m_dirnameops->hashname(name);
473 	args.dp = dp;
474 	args.whichfork = XFS_DATA_FORK;
475 	args.trans = tp;
476 	args.op_flags = XFS_DA_OP_JUSTCHECK | XFS_DA_OP_ADDNAME |
477 							XFS_DA_OP_OKNOENT;
478 
479 	if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
480 		rval = xfs_dir2_sf_addname(&args);
481 	else if ((rval = xfs_dir2_isblock(tp, dp, &v)))
482 		return rval;
483 	else if (v)
484 		rval = xfs_dir2_block_addname(&args);
485 	else if ((rval = xfs_dir2_isleaf(tp, dp, &v)))
486 		return rval;
487 	else if (v)
488 		rval = xfs_dir2_leaf_addname(&args);
489 	else
490 		rval = xfs_dir2_node_addname(&args);
491 	return rval;
492 }
493 
494 /*
495  * Utility routines.
496  */
497 
498 /*
499  * Add a block to the directory.
500  *
501  * This routine is for data and free blocks, not leaf/node blocks which are
502  * handled by xfs_da_grow_inode.
503  */
504 int
xfs_dir2_grow_inode(struct xfs_da_args * args,int space,xfs_dir2_db_t * dbp)505 xfs_dir2_grow_inode(
506 	struct xfs_da_args	*args,
507 	int			space,	/* v2 dir's space XFS_DIR2_xxx_SPACE */
508 	xfs_dir2_db_t		*dbp)	/* out: block number added */
509 {
510 	struct xfs_inode	*dp = args->dp;
511 	struct xfs_mount	*mp = dp->i_mount;
512 	xfs_fileoff_t		bno;	/* directory offset of new block */
513 	int			count;	/* count of filesystem blocks */
514 	int			error;
515 
516 	trace_xfs_dir2_grow_inode(args, space);
517 
518 	/*
519 	 * Set lowest possible block in the space requested.
520 	 */
521 	bno = XFS_B_TO_FSBT(mp, space * XFS_DIR2_SPACE_SIZE);
522 	count = mp->m_dirblkfsbs;
523 
524 	error = xfs_da_grow_inode_int(args, &bno, count);
525 	if (error)
526 		return error;
527 
528 	*dbp = xfs_dir2_da_to_db(mp, (xfs_dablk_t)bno);
529 
530 	/*
531 	 * Update file's size if this is the data space and it grew.
532 	 */
533 	if (space == XFS_DIR2_DATA_SPACE) {
534 		xfs_fsize_t	size;		/* directory file (data) size */
535 
536 		size = XFS_FSB_TO_B(mp, bno + count);
537 		if (size > dp->i_d.di_size) {
538 			dp->i_d.di_size = size;
539 			xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
540 		}
541 	}
542 	return 0;
543 }
544 
545 /*
546  * See if the directory is a single-block form directory.
547  */
548 int
xfs_dir2_isblock(xfs_trans_t * tp,xfs_inode_t * dp,int * vp)549 xfs_dir2_isblock(
550 	xfs_trans_t	*tp,
551 	xfs_inode_t	*dp,
552 	int		*vp)		/* out: 1 is block, 0 is not block */
553 {
554 	xfs_fileoff_t	last;		/* last file offset */
555 	xfs_mount_t	*mp;
556 	int		rval;
557 
558 	mp = dp->i_mount;
559 	if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))
560 		return rval;
561 	rval = XFS_FSB_TO_B(mp, last) == mp->m_dirblksize;
562 	ASSERT(rval == 0 || dp->i_d.di_size == mp->m_dirblksize);
563 	*vp = rval;
564 	return 0;
565 }
566 
567 /*
568  * See if the directory is a single-leaf form directory.
569  */
570 int
xfs_dir2_isleaf(xfs_trans_t * tp,xfs_inode_t * dp,int * vp)571 xfs_dir2_isleaf(
572 	xfs_trans_t	*tp,
573 	xfs_inode_t	*dp,
574 	int		*vp)		/* out: 1 is leaf, 0 is not leaf */
575 {
576 	xfs_fileoff_t	last;		/* last file offset */
577 	xfs_mount_t	*mp;
578 	int		rval;
579 
580 	mp = dp->i_mount;
581 	if ((rval = xfs_bmap_last_offset(tp, dp, &last, XFS_DATA_FORK)))
582 		return rval;
583 	*vp = last == mp->m_dirleafblk + (1 << mp->m_sb.sb_dirblklog);
584 	return 0;
585 }
586 
587 /*
588  * Remove the given block from the directory.
589  * This routine is used for data and free blocks, leaf/node are done
590  * by xfs_da_shrink_inode.
591  */
592 int
xfs_dir2_shrink_inode(xfs_da_args_t * args,xfs_dir2_db_t db,xfs_dabuf_t * bp)593 xfs_dir2_shrink_inode(
594 	xfs_da_args_t	*args,
595 	xfs_dir2_db_t	db,
596 	xfs_dabuf_t	*bp)
597 {
598 	xfs_fileoff_t	bno;		/* directory file offset */
599 	xfs_dablk_t	da;		/* directory file offset */
600 	int		done;		/* bunmap is finished */
601 	xfs_inode_t	*dp;
602 	int		error;
603 	xfs_mount_t	*mp;
604 	xfs_trans_t	*tp;
605 
606 	trace_xfs_dir2_shrink_inode(args, db);
607 
608 	dp = args->dp;
609 	mp = dp->i_mount;
610 	tp = args->trans;
611 	da = xfs_dir2_db_to_da(mp, db);
612 	/*
613 	 * Unmap the fsblock(s).
614 	 */
615 	if ((error = xfs_bunmapi(tp, dp, da, mp->m_dirblkfsbs,
616 			XFS_BMAPI_METADATA, 0, args->firstblock, args->flist,
617 			&done))) {
618 		/*
619 		 * ENOSPC actually can happen if we're in a removename with
620 		 * no space reservation, and the resulting block removal
621 		 * would cause a bmap btree split or conversion from extents
622 		 * to btree.  This can only happen for un-fragmented
623 		 * directory blocks, since you need to be punching out
624 		 * the middle of an extent.
625 		 * In this case we need to leave the block in the file,
626 		 * and not binval it.
627 		 * So the block has to be in a consistent empty state
628 		 * and appropriately logged.
629 		 * We don't free up the buffer, the caller can tell it
630 		 * hasn't happened since it got an error back.
631 		 */
632 		return error;
633 	}
634 	ASSERT(done);
635 	/*
636 	 * Invalidate the buffer from the transaction.
637 	 */
638 	xfs_da_binval(tp, bp);
639 	/*
640 	 * If it's not a data block, we're done.
641 	 */
642 	if (db >= XFS_DIR2_LEAF_FIRSTDB(mp))
643 		return 0;
644 	/*
645 	 * If the block isn't the last one in the directory, we're done.
646 	 */
647 	if (dp->i_d.di_size > xfs_dir2_db_off_to_byte(mp, db + 1, 0))
648 		return 0;
649 	bno = da;
650 	if ((error = xfs_bmap_last_before(tp, dp, &bno, XFS_DATA_FORK))) {
651 		/*
652 		 * This can't really happen unless there's kernel corruption.
653 		 */
654 		return error;
655 	}
656 	if (db == mp->m_dirdatablk)
657 		ASSERT(bno == 0);
658 	else
659 		ASSERT(bno > 0);
660 	/*
661 	 * Set the size to the new last block.
662 	 */
663 	dp->i_d.di_size = XFS_FSB_TO_B(mp, bno);
664 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
665 	return 0;
666 }
667