xref: /linux/fs/xfs/xfs_symlink.c (revision ff5599816711d2e67da2d7561fd36ac48debd433)
1 /*
2  * Copyright (c) 2000-2006 Silicon Graphics, Inc.
3  * Copyright (c) 2012-2013 Red Hat, Inc.
4  * All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it would be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program; if not, write the Free Software Foundation,
17  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
18  */
19 #include "xfs.h"
20 #include "xfs_fs.h"
21 #include "xfs_types.h"
22 #include "xfs_bit.h"
23 #include "xfs_log.h"
24 #include "xfs_trans.h"
25 #include "xfs_sb.h"
26 #include "xfs_ag.h"
27 #include "xfs_dir2.h"
28 #include "xfs_mount.h"
29 #include "xfs_da_btree.h"
30 #include "xfs_bmap_btree.h"
31 #include "xfs_ialloc_btree.h"
32 #include "xfs_dinode.h"
33 #include "xfs_inode.h"
34 #include "xfs_inode_item.h"
35 #include "xfs_itable.h"
36 #include "xfs_ialloc.h"
37 #include "xfs_alloc.h"
38 #include "xfs_bmap.h"
39 #include "xfs_error.h"
40 #include "xfs_quota.h"
41 #include "xfs_utils.h"
42 #include "xfs_trans_space.h"
43 #include "xfs_log_priv.h"
44 #include "xfs_trace.h"
45 #include "xfs_symlink.h"
46 #include "xfs_cksum.h"
47 #include "xfs_buf_item.h"
48 
49 
50 /*
51  * Each contiguous block has a header, so it is not just a simple pathlen
52  * to FSB conversion.
53  */
54 int
55 xfs_symlink_blocks(
56 	struct xfs_mount *mp,
57 	int		pathlen)
58 {
59 	int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
60 
61 	return (pathlen + buflen - 1) / buflen;
62 }
63 
64 static int
65 xfs_symlink_hdr_set(
66 	struct xfs_mount	*mp,
67 	xfs_ino_t		ino,
68 	uint32_t		offset,
69 	uint32_t		size,
70 	struct xfs_buf		*bp)
71 {
72 	struct xfs_dsymlink_hdr	*dsl = bp->b_addr;
73 
74 	if (!xfs_sb_version_hascrc(&mp->m_sb))
75 		return 0;
76 
77 	dsl->sl_magic = cpu_to_be32(XFS_SYMLINK_MAGIC);
78 	dsl->sl_offset = cpu_to_be32(offset);
79 	dsl->sl_bytes = cpu_to_be32(size);
80 	uuid_copy(&dsl->sl_uuid, &mp->m_sb.sb_uuid);
81 	dsl->sl_owner = cpu_to_be64(ino);
82 	dsl->sl_blkno = cpu_to_be64(bp->b_bn);
83 	bp->b_ops = &xfs_symlink_buf_ops;
84 
85 	return sizeof(struct xfs_dsymlink_hdr);
86 }
87 
88 /*
89  * Checking of the symlink header is split into two parts. the verifier does
90  * CRC, location and bounds checking, the unpacking function checks the path
91  * parameters and owner.
92  */
93 bool
94 xfs_symlink_hdr_ok(
95 	struct xfs_mount	*mp,
96 	xfs_ino_t		ino,
97 	uint32_t		offset,
98 	uint32_t		size,
99 	struct xfs_buf		*bp)
100 {
101 	struct xfs_dsymlink_hdr *dsl = bp->b_addr;
102 
103 	if (offset != be32_to_cpu(dsl->sl_offset))
104 		return false;
105 	if (size != be32_to_cpu(dsl->sl_bytes))
106 		return false;
107 	if (ino != be64_to_cpu(dsl->sl_owner))
108 		return false;
109 
110 	/* ok */
111 	return true;
112 }
113 
114 static bool
115 xfs_symlink_verify(
116 	struct xfs_buf		*bp)
117 {
118 	struct xfs_mount	*mp = bp->b_target->bt_mount;
119 	struct xfs_dsymlink_hdr	*dsl = bp->b_addr;
120 
121 	if (!xfs_sb_version_hascrc(&mp->m_sb))
122 		return false;
123 	if (dsl->sl_magic != cpu_to_be32(XFS_SYMLINK_MAGIC))
124 		return false;
125 	if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_uuid))
126 		return false;
127 	if (bp->b_bn != be64_to_cpu(dsl->sl_blkno))
128 		return false;
129 	if (be32_to_cpu(dsl->sl_offset) +
130 				be32_to_cpu(dsl->sl_bytes) >= MAXPATHLEN)
131 		return false;
132 	if (dsl->sl_owner == 0)
133 		return false;
134 
135 	return true;
136 }
137 
138 static void
139 xfs_symlink_read_verify(
140 	struct xfs_buf	*bp)
141 {
142 	struct xfs_mount *mp = bp->b_target->bt_mount;
143 
144 	/* no verification of non-crc buffers */
145 	if (!xfs_sb_version_hascrc(&mp->m_sb))
146 		return;
147 
148 	if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
149 				  offsetof(struct xfs_dsymlink_hdr, sl_crc)) ||
150 	    !xfs_symlink_verify(bp)) {
151 		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
152 		xfs_buf_ioerror(bp, EFSCORRUPTED);
153 	}
154 }
155 
156 static void
157 xfs_symlink_write_verify(
158 	struct xfs_buf	*bp)
159 {
160 	struct xfs_mount *mp = bp->b_target->bt_mount;
161 	struct xfs_buf_log_item	*bip = bp->b_fspriv;
162 
163 	/* no verification of non-crc buffers */
164 	if (!xfs_sb_version_hascrc(&mp->m_sb))
165 		return;
166 
167 	if (!xfs_symlink_verify(bp)) {
168 		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
169 		xfs_buf_ioerror(bp, EFSCORRUPTED);
170 		return;
171 	}
172 
173 	if (bip) {
174 		struct xfs_dsymlink_hdr *dsl = bp->b_addr;
175 		dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
176 	}
177 	xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
178 			 offsetof(struct xfs_dsymlink_hdr, sl_crc));
179 }
180 
181 const struct xfs_buf_ops xfs_symlink_buf_ops = {
182 	.verify_read = xfs_symlink_read_verify,
183 	.verify_write = xfs_symlink_write_verify,
184 };
185 
186 void
187 xfs_symlink_local_to_remote(
188 	struct xfs_trans	*tp,
189 	struct xfs_buf		*bp,
190 	struct xfs_inode	*ip,
191 	struct xfs_ifork	*ifp)
192 {
193 	struct xfs_mount	*mp = ip->i_mount;
194 	char			*buf;
195 
196 	if (!xfs_sb_version_hascrc(&mp->m_sb)) {
197 		bp->b_ops = NULL;
198 		memcpy(bp->b_addr, ifp->if_u1.if_data, ifp->if_bytes);
199 		return;
200 	}
201 
202 	/*
203 	 * As this symlink fits in an inode literal area, it must also fit in
204 	 * the smallest buffer the filesystem supports.
205 	 */
206 	ASSERT(BBTOB(bp->b_length) >=
207 			ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr));
208 
209 	bp->b_ops = &xfs_symlink_buf_ops;
210 
211 	buf = bp->b_addr;
212 	buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp);
213 	memcpy(buf, ifp->if_u1.if_data, ifp->if_bytes);
214 }
215 
216 /* ----- Kernel only functions below ----- */
217 STATIC int
218 xfs_readlink_bmap(
219 	struct xfs_inode	*ip,
220 	char			*link)
221 {
222 	struct xfs_mount	*mp = ip->i_mount;
223 	struct xfs_bmbt_irec	mval[XFS_SYMLINK_MAPS];
224 	struct xfs_buf		*bp;
225 	xfs_daddr_t		d;
226 	char			*cur_chunk;
227 	int			pathlen = ip->i_d.di_size;
228 	int			nmaps = XFS_SYMLINK_MAPS;
229 	int			byte_cnt;
230 	int			n;
231 	int			error = 0;
232 	int			fsblocks = 0;
233 	int			offset;
234 
235 	fsblocks = xfs_symlink_blocks(mp, pathlen);
236 	error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
237 	if (error)
238 		goto out;
239 
240 	offset = 0;
241 	for (n = 0; n < nmaps; n++) {
242 		d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
243 		byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
244 
245 		bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
246 				  &xfs_symlink_buf_ops);
247 		if (!bp)
248 			return XFS_ERROR(ENOMEM);
249 		error = bp->b_error;
250 		if (error) {
251 			xfs_buf_ioerror_alert(bp, __func__);
252 			xfs_buf_relse(bp);
253 			goto out;
254 		}
255 		byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
256 		if (pathlen < byte_cnt)
257 			byte_cnt = pathlen;
258 
259 		cur_chunk = bp->b_addr;
260 		if (xfs_sb_version_hascrc(&mp->m_sb)) {
261 			if (!xfs_symlink_hdr_ok(mp, ip->i_ino, offset,
262 							byte_cnt, bp)) {
263 				error = EFSCORRUPTED;
264 				xfs_alert(mp,
265 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
266 					offset, byte_cnt, ip->i_ino);
267 				xfs_buf_relse(bp);
268 				goto out;
269 
270 			}
271 
272 			cur_chunk += sizeof(struct xfs_dsymlink_hdr);
273 		}
274 
275 		memcpy(link + offset, bp->b_addr, byte_cnt);
276 
277 		pathlen -= byte_cnt;
278 		offset += byte_cnt;
279 
280 		xfs_buf_relse(bp);
281 	}
282 	ASSERT(pathlen == 0);
283 
284 	link[ip->i_d.di_size] = '\0';
285 	error = 0;
286 
287  out:
288 	return error;
289 }
290 
291 int
292 xfs_readlink(
293 	struct xfs_inode *ip,
294 	char		*link)
295 {
296 	struct xfs_mount *mp = ip->i_mount;
297 	xfs_fsize_t	pathlen;
298 	int		error = 0;
299 
300 	trace_xfs_readlink(ip);
301 
302 	if (XFS_FORCED_SHUTDOWN(mp))
303 		return XFS_ERROR(EIO);
304 
305 	xfs_ilock(ip, XFS_ILOCK_SHARED);
306 
307 	pathlen = ip->i_d.di_size;
308 	if (!pathlen)
309 		goto out;
310 
311 	if (pathlen < 0 || pathlen > MAXPATHLEN) {
312 		xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
313 			 __func__, (unsigned long long) ip->i_ino,
314 			 (long long) pathlen);
315 		ASSERT(0);
316 		error = XFS_ERROR(EFSCORRUPTED);
317 		goto out;
318 	}
319 
320 
321 	if (ip->i_df.if_flags & XFS_IFINLINE) {
322 		memcpy(link, ip->i_df.if_u1.if_data, pathlen);
323 		link[pathlen] = '\0';
324 	} else {
325 		error = xfs_readlink_bmap(ip, link);
326 	}
327 
328  out:
329 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
330 	return error;
331 }
332 
333 int
334 xfs_symlink(
335 	struct xfs_inode	*dp,
336 	struct xfs_name		*link_name,
337 	const char		*target_path,
338 	umode_t			mode,
339 	struct xfs_inode	**ipp)
340 {
341 	struct xfs_mount	*mp = dp->i_mount;
342 	struct xfs_trans	*tp = NULL;
343 	struct xfs_inode	*ip = NULL;
344 	int			error = 0;
345 	int			pathlen;
346 	struct xfs_bmap_free	free_list;
347 	xfs_fsblock_t		first_block;
348 	bool			unlock_dp_on_error = false;
349 	uint			cancel_flags;
350 	int			committed;
351 	xfs_fileoff_t		first_fsb;
352 	xfs_filblks_t		fs_blocks;
353 	int			nmaps;
354 	struct xfs_bmbt_irec	mval[XFS_SYMLINK_MAPS];
355 	xfs_daddr_t		d;
356 	const char		*cur_chunk;
357 	int			byte_cnt;
358 	int			n;
359 	xfs_buf_t		*bp;
360 	prid_t			prid;
361 	struct xfs_dquot	*udqp = NULL;
362 	struct xfs_dquot	*gdqp = NULL;
363 	uint			resblks;
364 
365 	*ipp = NULL;
366 
367 	trace_xfs_symlink(dp, link_name);
368 
369 	if (XFS_FORCED_SHUTDOWN(mp))
370 		return XFS_ERROR(EIO);
371 
372 	/*
373 	 * Check component lengths of the target path name.
374 	 */
375 	pathlen = strlen(target_path);
376 	if (pathlen >= MAXPATHLEN)      /* total string too long */
377 		return XFS_ERROR(ENAMETOOLONG);
378 
379 	udqp = gdqp = NULL;
380 	if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
381 		prid = xfs_get_projid(dp);
382 	else
383 		prid = XFS_PROJID_DEFAULT;
384 
385 	/*
386 	 * Make sure that we have allocated dquot(s) on disk.
387 	 */
388 	error = xfs_qm_vop_dqalloc(dp, current_fsuid(), current_fsgid(), prid,
389 			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp);
390 	if (error)
391 		goto std_return;
392 
393 	tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
394 	cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
395 	/*
396 	 * The symlink will fit into the inode data fork?
397 	 * There can't be any attributes so we get the whole variable part.
398 	 */
399 	if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
400 		fs_blocks = 0;
401 	else
402 		fs_blocks = xfs_symlink_blocks(mp, pathlen);
403 	resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
404 	error = xfs_trans_reserve(tp, resblks, XFS_SYMLINK_LOG_RES(mp), 0,
405 			XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
406 	if (error == ENOSPC && fs_blocks == 0) {
407 		resblks = 0;
408 		error = xfs_trans_reserve(tp, 0, XFS_SYMLINK_LOG_RES(mp), 0,
409 				XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
410 	}
411 	if (error) {
412 		cancel_flags = 0;
413 		goto error_return;
414 	}
415 
416 	xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
417 	unlock_dp_on_error = true;
418 
419 	/*
420 	 * Check whether the directory allows new symlinks or not.
421 	 */
422 	if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
423 		error = XFS_ERROR(EPERM);
424 		goto error_return;
425 	}
426 
427 	/*
428 	 * Reserve disk quota : blocks and inode.
429 	 */
430 	error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp, resblks, 1, 0);
431 	if (error)
432 		goto error_return;
433 
434 	/*
435 	 * Check for ability to enter directory entry, if no space reserved.
436 	 */
437 	error = xfs_dir_canenter(tp, dp, link_name, resblks);
438 	if (error)
439 		goto error_return;
440 	/*
441 	 * Initialize the bmap freelist prior to calling either
442 	 * bmapi or the directory create code.
443 	 */
444 	xfs_bmap_init(&free_list, &first_block);
445 
446 	/*
447 	 * Allocate an inode for the symlink.
448 	 */
449 	error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
450 			       prid, resblks > 0, &ip, NULL);
451 	if (error) {
452 		if (error == ENOSPC)
453 			goto error_return;
454 		goto error1;
455 	}
456 
457 	/*
458 	 * An error after we've joined dp to the transaction will result in the
459 	 * transaction cancel unlocking dp so don't do it explicitly in the
460 	 * error path.
461 	 */
462 	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
463 	unlock_dp_on_error = false;
464 
465 	/*
466 	 * Also attach the dquot(s) to it, if applicable.
467 	 */
468 	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp);
469 
470 	if (resblks)
471 		resblks -= XFS_IALLOC_SPACE_RES(mp);
472 	/*
473 	 * If the symlink will fit into the inode, write it inline.
474 	 */
475 	if (pathlen <= XFS_IFORK_DSIZE(ip)) {
476 		xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
477 		memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
478 		ip->i_d.di_size = pathlen;
479 
480 		/*
481 		 * The inode was initially created in extent format.
482 		 */
483 		ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
484 		ip->i_df.if_flags |= XFS_IFINLINE;
485 
486 		ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
487 		xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
488 
489 	} else {
490 		int	offset;
491 
492 		first_fsb = 0;
493 		nmaps = XFS_SYMLINK_MAPS;
494 
495 		error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
496 				  XFS_BMAPI_METADATA, &first_block, resblks,
497 				  mval, &nmaps, &free_list);
498 		if (error)
499 			goto error2;
500 
501 		if (resblks)
502 			resblks -= fs_blocks;
503 		ip->i_d.di_size = pathlen;
504 		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
505 
506 		cur_chunk = target_path;
507 		offset = 0;
508 		for (n = 0; n < nmaps; n++) {
509 			char	*buf;
510 
511 			d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
512 			byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
513 			bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
514 					       BTOBB(byte_cnt), 0);
515 			if (!bp) {
516 				error = ENOMEM;
517 				goto error2;
518 			}
519 			bp->b_ops = &xfs_symlink_buf_ops;
520 
521 			byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
522 			byte_cnt = min(byte_cnt, pathlen);
523 
524 			buf = bp->b_addr;
525 			buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
526 						   byte_cnt, bp);
527 
528 			memcpy(buf, cur_chunk, byte_cnt);
529 
530 			cur_chunk += byte_cnt;
531 			pathlen -= byte_cnt;
532 			offset += byte_cnt;
533 
534 			xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
535 							(char *)bp->b_addr);
536 		}
537 		ASSERT(pathlen == 0);
538 	}
539 
540 	/*
541 	 * Create the directory entry for the symlink.
542 	 */
543 	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
544 					&first_block, &free_list, resblks);
545 	if (error)
546 		goto error2;
547 	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
548 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
549 
550 	/*
551 	 * If this is a synchronous mount, make sure that the
552 	 * symlink transaction goes to disk before returning to
553 	 * the user.
554 	 */
555 	if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
556 		xfs_trans_set_sync(tp);
557 	}
558 
559 	error = xfs_bmap_finish(&tp, &free_list, &committed);
560 	if (error) {
561 		goto error2;
562 	}
563 	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
564 	xfs_qm_dqrele(udqp);
565 	xfs_qm_dqrele(gdqp);
566 
567 	*ipp = ip;
568 	return 0;
569 
570  error2:
571 	IRELE(ip);
572  error1:
573 	xfs_bmap_cancel(&free_list);
574 	cancel_flags |= XFS_TRANS_ABORT;
575  error_return:
576 	xfs_trans_cancel(tp, cancel_flags);
577 	xfs_qm_dqrele(udqp);
578 	xfs_qm_dqrele(gdqp);
579 
580 	if (unlock_dp_on_error)
581 		xfs_iunlock(dp, XFS_ILOCK_EXCL);
582  std_return:
583 	return error;
584 }
585 
586 /*
587  * Free a symlink that has blocks associated with it.
588  */
589 STATIC int
590 xfs_inactive_symlink_rmt(
591 	xfs_inode_t	*ip,
592 	xfs_trans_t	**tpp)
593 {
594 	xfs_buf_t	*bp;
595 	int		committed;
596 	int		done;
597 	int		error;
598 	xfs_fsblock_t	first_block;
599 	xfs_bmap_free_t	free_list;
600 	int		i;
601 	xfs_mount_t	*mp;
602 	xfs_bmbt_irec_t	mval[XFS_SYMLINK_MAPS];
603 	int		nmaps;
604 	xfs_trans_t	*ntp;
605 	int		size;
606 	xfs_trans_t	*tp;
607 
608 	tp = *tpp;
609 	mp = ip->i_mount;
610 	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
611 	/*
612 	 * We're freeing a symlink that has some
613 	 * blocks allocated to it.  Free the
614 	 * blocks here.  We know that we've got
615 	 * either 1 or 2 extents and that we can
616 	 * free them all in one bunmapi call.
617 	 */
618 	ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
619 
620 	/*
621 	 * Lock the inode, fix the size, and join it to the transaction.
622 	 * Hold it so in the normal path, we still have it locked for
623 	 * the second transaction.  In the error paths we need it
624 	 * held so the cancel won't rele it, see below.
625 	 */
626 	size = (int)ip->i_d.di_size;
627 	ip->i_d.di_size = 0;
628 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
629 	/*
630 	 * Find the block(s) so we can inval and unmap them.
631 	 */
632 	done = 0;
633 	xfs_bmap_init(&free_list, &first_block);
634 	nmaps = ARRAY_SIZE(mval);
635 	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
636 				mval, &nmaps, 0);
637 	if (error)
638 		goto error0;
639 	/*
640 	 * Invalidate the block(s). No validation is done.
641 	 */
642 	for (i = 0; i < nmaps; i++) {
643 		bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
644 			XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
645 			XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
646 		if (!bp) {
647 			error = ENOMEM;
648 			goto error1;
649 		}
650 		xfs_trans_binval(tp, bp);
651 	}
652 	/*
653 	 * Unmap the dead block(s) to the free_list.
654 	 */
655 	if ((error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps,
656 			&first_block, &free_list, &done)))
657 		goto error1;
658 	ASSERT(done);
659 	/*
660 	 * Commit the first transaction.  This logs the EFI and the inode.
661 	 */
662 	if ((error = xfs_bmap_finish(&tp, &free_list, &committed)))
663 		goto error1;
664 	/*
665 	 * The transaction must have been committed, since there were
666 	 * actually extents freed by xfs_bunmapi.  See xfs_bmap_finish.
667 	 * The new tp has the extent freeing and EFDs.
668 	 */
669 	ASSERT(committed);
670 	/*
671 	 * The first xact was committed, so add the inode to the new one.
672 	 * Mark it dirty so it will be logged and moved forward in the log as
673 	 * part of every commit.
674 	 */
675 	xfs_trans_ijoin(tp, ip, 0);
676 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
677 	/*
678 	 * Get a new, empty transaction to return to our caller.
679 	 */
680 	ntp = xfs_trans_dup(tp);
681 	/*
682 	 * Commit the transaction containing extent freeing and EFDs.
683 	 * If we get an error on the commit here or on the reserve below,
684 	 * we need to unlock the inode since the new transaction doesn't
685 	 * have the inode attached.
686 	 */
687 	error = xfs_trans_commit(tp, 0);
688 	tp = ntp;
689 	if (error) {
690 		ASSERT(XFS_FORCED_SHUTDOWN(mp));
691 		goto error0;
692 	}
693 	/*
694 	 * transaction commit worked ok so we can drop the extra ticket
695 	 * reference that we gained in xfs_trans_dup()
696 	 */
697 	xfs_log_ticket_put(tp->t_ticket);
698 
699 	/*
700 	 * Remove the memory for extent descriptions (just bookkeeping).
701 	 */
702 	if (ip->i_df.if_bytes)
703 		xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
704 	ASSERT(ip->i_df.if_bytes == 0);
705 	/*
706 	 * Put an itruncate log reservation in the new transaction
707 	 * for our caller.
708 	 */
709 	if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
710 			XFS_TRANS_PERM_LOG_RES, XFS_ITRUNCATE_LOG_COUNT))) {
711 		ASSERT(XFS_FORCED_SHUTDOWN(mp));
712 		goto error0;
713 	}
714 
715 	xfs_trans_ijoin(tp, ip, 0);
716 	*tpp = tp;
717 	return 0;
718 
719  error1:
720 	xfs_bmap_cancel(&free_list);
721  error0:
722 	return error;
723 }
724 
725 /*
726  * xfs_inactive_symlink - free a symlink
727  */
728 int
729 xfs_inactive_symlink(
730 	struct xfs_inode	*ip,
731 	struct xfs_trans	**tp)
732 {
733 	struct xfs_mount	*mp = ip->i_mount;
734 	int			pathlen;
735 
736 	trace_xfs_inactive_symlink(ip);
737 
738 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
739 
740 	if (XFS_FORCED_SHUTDOWN(mp))
741 		return XFS_ERROR(EIO);
742 
743 	/*
744 	 * Zero length symlinks _can_ exist.
745 	 */
746 	pathlen = (int)ip->i_d.di_size;
747 	if (!pathlen)
748 		return 0;
749 
750 	if (pathlen < 0 || pathlen > MAXPATHLEN) {
751 		xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
752 			 __func__, (unsigned long long)ip->i_ino, pathlen);
753 		ASSERT(0);
754 		return XFS_ERROR(EFSCORRUPTED);
755 	}
756 
757 	if (ip->i_df.if_flags & XFS_IFINLINE) {
758 		if (ip->i_df.if_bytes > 0)
759 			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
760 					  XFS_DATA_FORK);
761 		ASSERT(ip->i_df.if_bytes == 0);
762 		return 0;
763 	}
764 
765 	/* remove the remote symlink */
766 	return xfs_inactive_symlink_rmt(ip, tp);
767 }
768