xref: /openbmc/linux/fs/xfs/xfs_symlink.c (revision c4c11dd1)
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 	struct xfs_dquot	*pdqp = NULL;
364 	uint			resblks;
365 
366 	*ipp = NULL;
367 
368 	trace_xfs_symlink(dp, link_name);
369 
370 	if (XFS_FORCED_SHUTDOWN(mp))
371 		return XFS_ERROR(EIO);
372 
373 	/*
374 	 * Check component lengths of the target path name.
375 	 */
376 	pathlen = strlen(target_path);
377 	if (pathlen >= MAXPATHLEN)      /* total string too long */
378 		return XFS_ERROR(ENAMETOOLONG);
379 
380 	udqp = gdqp = NULL;
381 	if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
382 		prid = xfs_get_projid(dp);
383 	else
384 		prid = XFS_PROJID_DEFAULT;
385 
386 	/*
387 	 * Make sure that we have allocated dquot(s) on disk.
388 	 */
389 	error = xfs_qm_vop_dqalloc(dp, current_fsuid(), current_fsgid(), prid,
390 		XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp);
391 	if (error)
392 		goto std_return;
393 
394 	tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
395 	cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
396 	/*
397 	 * The symlink will fit into the inode data fork?
398 	 * There can't be any attributes so we get the whole variable part.
399 	 */
400 	if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
401 		fs_blocks = 0;
402 	else
403 		fs_blocks = xfs_symlink_blocks(mp, pathlen);
404 	resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
405 	error = xfs_trans_reserve(tp, resblks, XFS_SYMLINK_LOG_RES(mp), 0,
406 			XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
407 	if (error == ENOSPC && fs_blocks == 0) {
408 		resblks = 0;
409 		error = xfs_trans_reserve(tp, 0, XFS_SYMLINK_LOG_RES(mp), 0,
410 				XFS_TRANS_PERM_LOG_RES, XFS_SYMLINK_LOG_COUNT);
411 	}
412 	if (error) {
413 		cancel_flags = 0;
414 		goto error_return;
415 	}
416 
417 	xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
418 	unlock_dp_on_error = true;
419 
420 	/*
421 	 * Check whether the directory allows new symlinks or not.
422 	 */
423 	if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
424 		error = XFS_ERROR(EPERM);
425 		goto error_return;
426 	}
427 
428 	/*
429 	 * Reserve disk quota : blocks and inode.
430 	 */
431 	error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
432 						pdqp, resblks, 1, 0);
433 	if (error)
434 		goto error_return;
435 
436 	/*
437 	 * Check for ability to enter directory entry, if no space reserved.
438 	 */
439 	error = xfs_dir_canenter(tp, dp, link_name, resblks);
440 	if (error)
441 		goto error_return;
442 	/*
443 	 * Initialize the bmap freelist prior to calling either
444 	 * bmapi or the directory create code.
445 	 */
446 	xfs_bmap_init(&free_list, &first_block);
447 
448 	/*
449 	 * Allocate an inode for the symlink.
450 	 */
451 	error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
452 			       prid, resblks > 0, &ip, NULL);
453 	if (error) {
454 		if (error == ENOSPC)
455 			goto error_return;
456 		goto error1;
457 	}
458 
459 	/*
460 	 * An error after we've joined dp to the transaction will result in the
461 	 * transaction cancel unlocking dp so don't do it explicitly in the
462 	 * error path.
463 	 */
464 	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
465 	unlock_dp_on_error = false;
466 
467 	/*
468 	 * Also attach the dquot(s) to it, if applicable.
469 	 */
470 	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
471 
472 	if (resblks)
473 		resblks -= XFS_IALLOC_SPACE_RES(mp);
474 	/*
475 	 * If the symlink will fit into the inode, write it inline.
476 	 */
477 	if (pathlen <= XFS_IFORK_DSIZE(ip)) {
478 		xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
479 		memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
480 		ip->i_d.di_size = pathlen;
481 
482 		/*
483 		 * The inode was initially created in extent format.
484 		 */
485 		ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
486 		ip->i_df.if_flags |= XFS_IFINLINE;
487 
488 		ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
489 		xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
490 
491 	} else {
492 		int	offset;
493 
494 		first_fsb = 0;
495 		nmaps = XFS_SYMLINK_MAPS;
496 
497 		error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
498 				  XFS_BMAPI_METADATA, &first_block, resblks,
499 				  mval, &nmaps, &free_list);
500 		if (error)
501 			goto error2;
502 
503 		if (resblks)
504 			resblks -= fs_blocks;
505 		ip->i_d.di_size = pathlen;
506 		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
507 
508 		cur_chunk = target_path;
509 		offset = 0;
510 		for (n = 0; n < nmaps; n++) {
511 			char	*buf;
512 
513 			d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
514 			byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
515 			bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
516 					       BTOBB(byte_cnt), 0);
517 			if (!bp) {
518 				error = ENOMEM;
519 				goto error2;
520 			}
521 			bp->b_ops = &xfs_symlink_buf_ops;
522 
523 			byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
524 			byte_cnt = min(byte_cnt, pathlen);
525 
526 			buf = bp->b_addr;
527 			buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
528 						   byte_cnt, bp);
529 
530 			memcpy(buf, cur_chunk, byte_cnt);
531 
532 			cur_chunk += byte_cnt;
533 			pathlen -= byte_cnt;
534 			offset += byte_cnt;
535 
536 			xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
537 							(char *)bp->b_addr);
538 		}
539 		ASSERT(pathlen == 0);
540 	}
541 
542 	/*
543 	 * Create the directory entry for the symlink.
544 	 */
545 	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
546 					&first_block, &free_list, resblks);
547 	if (error)
548 		goto error2;
549 	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
550 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
551 
552 	/*
553 	 * If this is a synchronous mount, make sure that the
554 	 * symlink transaction goes to disk before returning to
555 	 * the user.
556 	 */
557 	if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
558 		xfs_trans_set_sync(tp);
559 	}
560 
561 	error = xfs_bmap_finish(&tp, &free_list, &committed);
562 	if (error) {
563 		goto error2;
564 	}
565 	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
566 	xfs_qm_dqrele(udqp);
567 	xfs_qm_dqrele(gdqp);
568 	xfs_qm_dqrele(pdqp);
569 
570 	*ipp = ip;
571 	return 0;
572 
573  error2:
574 	IRELE(ip);
575  error1:
576 	xfs_bmap_cancel(&free_list);
577 	cancel_flags |= XFS_TRANS_ABORT;
578  error_return:
579 	xfs_trans_cancel(tp, cancel_flags);
580 	xfs_qm_dqrele(udqp);
581 	xfs_qm_dqrele(gdqp);
582 	xfs_qm_dqrele(pdqp);
583 
584 	if (unlock_dp_on_error)
585 		xfs_iunlock(dp, XFS_ILOCK_EXCL);
586  std_return:
587 	return error;
588 }
589 
590 /*
591  * Free a symlink that has blocks associated with it.
592  */
593 STATIC int
594 xfs_inactive_symlink_rmt(
595 	xfs_inode_t	*ip,
596 	xfs_trans_t	**tpp)
597 {
598 	xfs_buf_t	*bp;
599 	int		committed;
600 	int		done;
601 	int		error;
602 	xfs_fsblock_t	first_block;
603 	xfs_bmap_free_t	free_list;
604 	int		i;
605 	xfs_mount_t	*mp;
606 	xfs_bmbt_irec_t	mval[XFS_SYMLINK_MAPS];
607 	int		nmaps;
608 	xfs_trans_t	*ntp;
609 	int		size;
610 	xfs_trans_t	*tp;
611 
612 	tp = *tpp;
613 	mp = ip->i_mount;
614 	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
615 	/*
616 	 * We're freeing a symlink that has some
617 	 * blocks allocated to it.  Free the
618 	 * blocks here.  We know that we've got
619 	 * either 1 or 2 extents and that we can
620 	 * free them all in one bunmapi call.
621 	 */
622 	ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
623 
624 	/*
625 	 * Lock the inode, fix the size, and join it to the transaction.
626 	 * Hold it so in the normal path, we still have it locked for
627 	 * the second transaction.  In the error paths we need it
628 	 * held so the cancel won't rele it, see below.
629 	 */
630 	size = (int)ip->i_d.di_size;
631 	ip->i_d.di_size = 0;
632 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
633 	/*
634 	 * Find the block(s) so we can inval and unmap them.
635 	 */
636 	done = 0;
637 	xfs_bmap_init(&free_list, &first_block);
638 	nmaps = ARRAY_SIZE(mval);
639 	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
640 				mval, &nmaps, 0);
641 	if (error)
642 		goto error0;
643 	/*
644 	 * Invalidate the block(s). No validation is done.
645 	 */
646 	for (i = 0; i < nmaps; i++) {
647 		bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
648 			XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
649 			XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
650 		if (!bp) {
651 			error = ENOMEM;
652 			goto error1;
653 		}
654 		xfs_trans_binval(tp, bp);
655 	}
656 	/*
657 	 * Unmap the dead block(s) to the free_list.
658 	 */
659 	if ((error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps,
660 			&first_block, &free_list, &done)))
661 		goto error1;
662 	ASSERT(done);
663 	/*
664 	 * Commit the first transaction.  This logs the EFI and the inode.
665 	 */
666 	if ((error = xfs_bmap_finish(&tp, &free_list, &committed)))
667 		goto error1;
668 	/*
669 	 * The transaction must have been committed, since there were
670 	 * actually extents freed by xfs_bunmapi.  See xfs_bmap_finish.
671 	 * The new tp has the extent freeing and EFDs.
672 	 */
673 	ASSERT(committed);
674 	/*
675 	 * The first xact was committed, so add the inode to the new one.
676 	 * Mark it dirty so it will be logged and moved forward in the log as
677 	 * part of every commit.
678 	 */
679 	xfs_trans_ijoin(tp, ip, 0);
680 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
681 	/*
682 	 * Get a new, empty transaction to return to our caller.
683 	 */
684 	ntp = xfs_trans_dup(tp);
685 	/*
686 	 * Commit the transaction containing extent freeing and EFDs.
687 	 * If we get an error on the commit here or on the reserve below,
688 	 * we need to unlock the inode since the new transaction doesn't
689 	 * have the inode attached.
690 	 */
691 	error = xfs_trans_commit(tp, 0);
692 	tp = ntp;
693 	if (error) {
694 		ASSERT(XFS_FORCED_SHUTDOWN(mp));
695 		goto error0;
696 	}
697 	/*
698 	 * transaction commit worked ok so we can drop the extra ticket
699 	 * reference that we gained in xfs_trans_dup()
700 	 */
701 	xfs_log_ticket_put(tp->t_ticket);
702 
703 	/*
704 	 * Remove the memory for extent descriptions (just bookkeeping).
705 	 */
706 	if (ip->i_df.if_bytes)
707 		xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
708 	ASSERT(ip->i_df.if_bytes == 0);
709 	/*
710 	 * Put an itruncate log reservation in the new transaction
711 	 * for our caller.
712 	 */
713 	if ((error = xfs_trans_reserve(tp, 0, XFS_ITRUNCATE_LOG_RES(mp), 0,
714 			XFS_TRANS_PERM_LOG_RES, XFS_ITRUNCATE_LOG_COUNT))) {
715 		ASSERT(XFS_FORCED_SHUTDOWN(mp));
716 		goto error0;
717 	}
718 
719 	xfs_trans_ijoin(tp, ip, 0);
720 	*tpp = tp;
721 	return 0;
722 
723  error1:
724 	xfs_bmap_cancel(&free_list);
725  error0:
726 	return error;
727 }
728 
729 /*
730  * xfs_inactive_symlink - free a symlink
731  */
732 int
733 xfs_inactive_symlink(
734 	struct xfs_inode	*ip,
735 	struct xfs_trans	**tp)
736 {
737 	struct xfs_mount	*mp = ip->i_mount;
738 	int			pathlen;
739 
740 	trace_xfs_inactive_symlink(ip);
741 
742 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
743 
744 	if (XFS_FORCED_SHUTDOWN(mp))
745 		return XFS_ERROR(EIO);
746 
747 	/*
748 	 * Zero length symlinks _can_ exist.
749 	 */
750 	pathlen = (int)ip->i_d.di_size;
751 	if (!pathlen)
752 		return 0;
753 
754 	if (pathlen < 0 || pathlen > MAXPATHLEN) {
755 		xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
756 			 __func__, (unsigned long long)ip->i_ino, pathlen);
757 		ASSERT(0);
758 		return XFS_ERROR(EFSCORRUPTED);
759 	}
760 
761 	if (ip->i_df.if_flags & XFS_IFINLINE) {
762 		if (ip->i_df.if_bytes > 0)
763 			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
764 					  XFS_DATA_FORK);
765 		ASSERT(ip->i_df.if_bytes == 0);
766 		return 0;
767 	}
768 
769 	/* remove the remote symlink */
770 	return xfs_inactive_symlink_rmt(ip, tp);
771 }
772