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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_shared.h"
21#include "xfs_fs.h"
22#include "xfs_format.h"
23#include "xfs_log_format.h"
24#include "xfs_trans_resv.h"
25#include "xfs_bit.h"
26#include "xfs_mount.h"
27#include "xfs_da_format.h"
28#include "xfs_da_btree.h"
29#include "xfs_defer.h"
30#include "xfs_dir2.h"
31#include "xfs_inode.h"
32#include "xfs_ialloc.h"
33#include "xfs_alloc.h"
34#include "xfs_bmap.h"
35#include "xfs_bmap_btree.h"
36#include "xfs_bmap_util.h"
37#include "xfs_error.h"
38#include "xfs_quota.h"
39#include "xfs_trans_space.h"
40#include "xfs_trace.h"
41#include "xfs_symlink.h"
42#include "xfs_trans.h"
43#include "xfs_log.h"
44
45/* ----- Kernel only functions below ----- */
46STATIC int
47xfs_readlink_bmap(
48 struct xfs_inode *ip,
49 char *link)
50{
51 struct xfs_mount *mp = ip->i_mount;
52 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
53 struct xfs_buf *bp;
54 xfs_daddr_t d;
55 char *cur_chunk;
56 int pathlen = ip->i_d.di_size;
57 int nmaps = XFS_SYMLINK_MAPS;
58 int byte_cnt;
59 int n;
60 int error = 0;
61 int fsblocks = 0;
62 int offset;
63
64 fsblocks = xfs_symlink_blocks(mp, pathlen);
65 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
66 if (error)
67 goto out;
68
69 offset = 0;
70 for (n = 0; n < nmaps; n++) {
71 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
72 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
73
74 bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
75 &xfs_symlink_buf_ops);
76 if (!bp)
77 return -ENOMEM;
78 error = bp->b_error;
79 if (error) {
80 xfs_buf_ioerror_alert(bp, __func__);
81 xfs_buf_relse(bp);
82
83 /* bad CRC means corrupted metadata */
84 if (error == -EFSBADCRC)
85 error = -EFSCORRUPTED;
86 goto out;
87 }
88 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
89 if (pathlen < byte_cnt)
90 byte_cnt = pathlen;
91
92 cur_chunk = bp->b_addr;
93 if (xfs_sb_version_hascrc(&mp->m_sb)) {
94 if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
95 byte_cnt, bp)) {
96 error = -EFSCORRUPTED;
97 xfs_alert(mp,
98"symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
99 offset, byte_cnt, ip->i_ino);
100 xfs_buf_relse(bp);
101 goto out;
102
103 }
104
105 cur_chunk += sizeof(struct xfs_dsymlink_hdr);
106 }
107
108 memcpy(link + offset, cur_chunk, byte_cnt);
109
110 pathlen -= byte_cnt;
111 offset += byte_cnt;
112
113 xfs_buf_relse(bp);
114 }
115 ASSERT(pathlen == 0);
116
117 link[ip->i_d.di_size] = '\0';
118 error = 0;
119
120 out:
121 return error;
122}
123
124int
125xfs_readlink(
126 struct xfs_inode *ip,
127 char *link)
128{
129 struct xfs_mount *mp = ip->i_mount;
130 xfs_fsize_t pathlen;
131 int error = 0;
132
133 trace_xfs_readlink(ip);
134
135 ASSERT(!(ip->i_df.if_flags & XFS_IFINLINE));
136
137 if (XFS_FORCED_SHUTDOWN(mp))
138 return -EIO;
139
140 xfs_ilock(ip, XFS_ILOCK_SHARED);
141
142 pathlen = ip->i_d.di_size;
143 if (!pathlen)
144 goto out;
145
146 if (pathlen < 0 || pathlen > MAXPATHLEN) {
147 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
148 __func__, (unsigned long long) ip->i_ino,
149 (long long) pathlen);
150 ASSERT(0);
151 error = -EFSCORRUPTED;
152 goto out;
153 }
154
155
156 error = xfs_readlink_bmap(ip, link);
157
158 out:
159 xfs_iunlock(ip, XFS_ILOCK_SHARED);
160 return error;
161}
162
163int
164xfs_symlink(
165 struct xfs_inode *dp,
166 struct xfs_name *link_name,
167 const char *target_path,
168 umode_t mode,
169 struct xfs_inode **ipp)
170{
171 struct xfs_mount *mp = dp->i_mount;
172 struct xfs_trans *tp = NULL;
173 struct xfs_inode *ip = NULL;
174 int error = 0;
175 int pathlen;
176 struct xfs_defer_ops dfops;
177 xfs_fsblock_t first_block;
178 bool unlock_dp_on_error = false;
179 xfs_fileoff_t first_fsb;
180 xfs_filblks_t fs_blocks;
181 int nmaps;
182 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
183 xfs_daddr_t d;
184 const char *cur_chunk;
185 int byte_cnt;
186 int n;
187 xfs_buf_t *bp;
188 prid_t prid;
189 struct xfs_dquot *udqp = NULL;
190 struct xfs_dquot *gdqp = NULL;
191 struct xfs_dquot *pdqp = NULL;
192 uint resblks;
193
194 *ipp = NULL;
195
196 trace_xfs_symlink(dp, link_name);
197
198 if (XFS_FORCED_SHUTDOWN(mp))
199 return -EIO;
200
201 /*
202 * Check component lengths of the target path name.
203 */
204 pathlen = strlen(target_path);
205 if (pathlen >= MAXPATHLEN) /* total string too long */
206 return -ENAMETOOLONG;
207
208 udqp = gdqp = NULL;
209 prid = xfs_get_initial_prid(dp);
210
211 /*
212 * Make sure that we have allocated dquot(s) on disk.
213 */
214 error = xfs_qm_vop_dqalloc(dp,
215 xfs_kuid_to_uid(current_fsuid()),
216 xfs_kgid_to_gid(current_fsgid()), prid,
217 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
218 &udqp, &gdqp, &pdqp);
219 if (error)
220 return error;
221
222 /*
223 * The symlink will fit into the inode data fork?
224 * There can't be any attributes so we get the whole variable part.
225 */
226 if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
227 fs_blocks = 0;
228 else
229 fs_blocks = xfs_symlink_blocks(mp, pathlen);
230 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
231
232 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, resblks, 0, 0, &tp);
233 if (error == -ENOSPC && fs_blocks == 0) {
234 resblks = 0;
235 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_symlink, 0, 0, 0,
236 &tp);
237 }
238 if (error)
239 goto out_release_inode;
240
241 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
242 unlock_dp_on_error = true;
243
244 /*
245 * Check whether the directory allows new symlinks or not.
246 */
247 if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
248 error = -EPERM;
249 goto out_trans_cancel;
250 }
251
252 /*
253 * Reserve disk quota : blocks and inode.
254 */
255 error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
256 pdqp, resblks, 1, 0);
257 if (error)
258 goto out_trans_cancel;
259
260 /*
261 * Check for ability to enter directory entry, if no space reserved.
262 */
263 if (!resblks) {
264 error = xfs_dir_canenter(tp, dp, link_name);
265 if (error)
266 goto out_trans_cancel;
267 }
268 /*
269 * Initialize the bmap freelist prior to calling either
270 * bmapi or the directory create code.
271 */
272 xfs_defer_init(&dfops, &first_block);
273
274 /*
275 * Allocate an inode for the symlink.
276 */
277 error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
278 prid, resblks > 0, &ip, NULL);
279 if (error)
280 goto out_trans_cancel;
281
282 /*
283 * Now we join the directory inode to the transaction. We do not do it
284 * earlier because xfs_dir_ialloc might commit the previous transaction
285 * (and release all the locks). An error from here on will result in
286 * the transaction cancel unlocking dp so don't do it explicitly in the
287 * error path.
288 */
289 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
290 unlock_dp_on_error = false;
291
292 /*
293 * Also attach the dquot(s) to it, if applicable.
294 */
295 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
296
297 if (resblks)
298 resblks -= XFS_IALLOC_SPACE_RES(mp);
299 /*
300 * If the symlink will fit into the inode, write it inline.
301 */
302 if (pathlen <= XFS_IFORK_DSIZE(ip)) {
303 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
304
305 ip->i_d.di_size = pathlen;
306 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
307 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
308 } else {
309 int offset;
310
311 first_fsb = 0;
312 nmaps = XFS_SYMLINK_MAPS;
313
314 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
315 XFS_BMAPI_METADATA, &first_block, resblks,
316 mval, &nmaps, &dfops);
317 if (error)
318 goto out_bmap_cancel;
319
320 if (resblks)
321 resblks -= fs_blocks;
322 ip->i_d.di_size = pathlen;
323 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
324
325 cur_chunk = target_path;
326 offset = 0;
327 for (n = 0; n < nmaps; n++) {
328 char *buf;
329
330 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
331 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
332 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
333 BTOBB(byte_cnt), 0);
334 if (!bp) {
335 error = -ENOMEM;
336 goto out_bmap_cancel;
337 }
338 bp->b_ops = &xfs_symlink_buf_ops;
339
340 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
341 byte_cnt = min(byte_cnt, pathlen);
342
343 buf = bp->b_addr;
344 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
345 byte_cnt, bp);
346
347 memcpy(buf, cur_chunk, byte_cnt);
348
349 cur_chunk += byte_cnt;
350 pathlen -= byte_cnt;
351 offset += byte_cnt;
352
353 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
354 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
355 (char *)bp->b_addr);
356 }
357 ASSERT(pathlen == 0);
358 }
359
360 /*
361 * Create the directory entry for the symlink.
362 */
363 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
364 &first_block, &dfops, resblks);
365 if (error)
366 goto out_bmap_cancel;
367 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
368 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
369
370 /*
371 * If this is a synchronous mount, make sure that the
372 * symlink transaction goes to disk before returning to
373 * the user.
374 */
375 if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
376 xfs_trans_set_sync(tp);
377 }
378
379 error = xfs_defer_finish(&tp, &dfops, NULL);
380 if (error)
381 goto out_bmap_cancel;
382
383 error = xfs_trans_commit(tp);
384 if (error)
385 goto out_release_inode;
386
387 xfs_qm_dqrele(udqp);
388 xfs_qm_dqrele(gdqp);
389 xfs_qm_dqrele(pdqp);
390
391 *ipp = ip;
392 return 0;
393
394out_bmap_cancel:
395 xfs_defer_cancel(&dfops);
396out_trans_cancel:
397 xfs_trans_cancel(tp);
398out_release_inode:
399 /*
400 * Wait until after the current transaction is aborted to finish the
401 * setup of the inode and release the inode. This prevents recursive
402 * transactions and deadlocks from xfs_inactive.
403 */
404 if (ip) {
405 xfs_finish_inode_setup(ip);
406 IRELE(ip);
407 }
408
409 xfs_qm_dqrele(udqp);
410 xfs_qm_dqrele(gdqp);
411 xfs_qm_dqrele(pdqp);
412
413 if (unlock_dp_on_error)
414 xfs_iunlock(dp, XFS_ILOCK_EXCL);
415 return error;
416}
417
418/*
419 * Free a symlink that has blocks associated with it.
420 */
421STATIC int
422xfs_inactive_symlink_rmt(
423 struct xfs_inode *ip)
424{
425 xfs_buf_t *bp;
426 int done;
427 int error;
428 xfs_fsblock_t first_block;
429 struct xfs_defer_ops dfops;
430 int i;
431 xfs_mount_t *mp;
432 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
433 int nmaps;
434 int size;
435 xfs_trans_t *tp;
436
437 mp = ip->i_mount;
438 ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
439 /*
440 * We're freeing a symlink that has some
441 * blocks allocated to it. Free the
442 * blocks here. We know that we've got
443 * either 1 or 2 extents and that we can
444 * free them all in one bunmapi call.
445 */
446 ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
447
448 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
449 if (error)
450 return error;
451
452 xfs_ilock(ip, XFS_ILOCK_EXCL);
453 xfs_trans_ijoin(tp, ip, 0);
454
455 /*
456 * Lock the inode, fix the size, and join it to the transaction.
457 * Hold it so in the normal path, we still have it locked for
458 * the second transaction. In the error paths we need it
459 * held so the cancel won't rele it, see below.
460 */
461 size = (int)ip->i_d.di_size;
462 ip->i_d.di_size = 0;
463 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
464 /*
465 * Find the block(s) so we can inval and unmap them.
466 */
467 done = 0;
468 xfs_defer_init(&dfops, &first_block);
469 nmaps = ARRAY_SIZE(mval);
470 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
471 mval, &nmaps, 0);
472 if (error)
473 goto error_trans_cancel;
474 /*
475 * Invalidate the block(s). No validation is done.
476 */
477 for (i = 0; i < nmaps; i++) {
478 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
479 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
480 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
481 if (!bp) {
482 error = -ENOMEM;
483 goto error_bmap_cancel;
484 }
485 xfs_trans_binval(tp, bp);
486 }
487 /*
488 * Unmap the dead block(s) to the dfops.
489 */
490 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps,
491 &first_block, &dfops, &done);
492 if (error)
493 goto error_bmap_cancel;
494 ASSERT(done);
495 /*
496 * Commit the first transaction. This logs the EFI and the inode.
497 */
498 error = xfs_defer_finish(&tp, &dfops, ip);
499 if (error)
500 goto error_bmap_cancel;
501 /*
502 * The first xact was committed, so add the inode to the new one.
503 * Mark it dirty so it will be logged and moved forward in the log as
504 * part of every commit.
505 */
506 xfs_trans_ijoin(tp, ip, 0);
507 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
508 /*
509 * Commit the transaction containing extent freeing and EFDs.
510 */
511 error = xfs_trans_commit(tp);
512 if (error) {
513 ASSERT(XFS_FORCED_SHUTDOWN(mp));
514 goto error_unlock;
515 }
516
517 /*
518 * Remove the memory for extent descriptions (just bookkeeping).
519 */
520 if (ip->i_df.if_bytes)
521 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
522 ASSERT(ip->i_df.if_bytes == 0);
523
524 xfs_iunlock(ip, XFS_ILOCK_EXCL);
525 return 0;
526
527error_bmap_cancel:
528 xfs_defer_cancel(&dfops);
529error_trans_cancel:
530 xfs_trans_cancel(tp);
531error_unlock:
532 xfs_iunlock(ip, XFS_ILOCK_EXCL);
533 return error;
534}
535
536/*
537 * xfs_inactive_symlink - free a symlink
538 */
539int
540xfs_inactive_symlink(
541 struct xfs_inode *ip)
542{
543 struct xfs_mount *mp = ip->i_mount;
544 int pathlen;
545
546 trace_xfs_inactive_symlink(ip);
547
548 if (XFS_FORCED_SHUTDOWN(mp))
549 return -EIO;
550
551 xfs_ilock(ip, XFS_ILOCK_EXCL);
552
553 /*
554 * Zero length symlinks _can_ exist.
555 */
556 pathlen = (int)ip->i_d.di_size;
557 if (!pathlen) {
558 xfs_iunlock(ip, XFS_ILOCK_EXCL);
559 return 0;
560 }
561
562 if (pathlen < 0 || pathlen > MAXPATHLEN) {
563 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
564 __func__, (unsigned long long)ip->i_ino, pathlen);
565 xfs_iunlock(ip, XFS_ILOCK_EXCL);
566 ASSERT(0);
567 return -EFSCORRUPTED;
568 }
569
570 if (ip->i_df.if_flags & XFS_IFINLINE) {
571 if (ip->i_df.if_bytes > 0)
572 xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
573 XFS_DATA_FORK);
574 xfs_iunlock(ip, XFS_ILOCK_EXCL);
575 ASSERT(ip->i_df.if_bytes == 0);
576 return 0;
577 }
578
579 xfs_iunlock(ip, XFS_ILOCK_EXCL);
580
581 /* remove the remote symlink */
582 return xfs_inactive_symlink_rmt(ip);
583}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 * Copyright (c) 2012-2013 Red Hat, Inc.
5 * All rights reserved.
6 */
7#include "xfs.h"
8#include "xfs_shared.h"
9#include "xfs_fs.h"
10#include "xfs_format.h"
11#include "xfs_log_format.h"
12#include "xfs_trans_resv.h"
13#include "xfs_bit.h"
14#include "xfs_mount.h"
15#include "xfs_dir2.h"
16#include "xfs_inode.h"
17#include "xfs_bmap.h"
18#include "xfs_bmap_btree.h"
19#include "xfs_quota.h"
20#include "xfs_symlink.h"
21#include "xfs_trans_space.h"
22#include "xfs_trace.h"
23#include "xfs_trans.h"
24#include "xfs_ialloc.h"
25#include "xfs_error.h"
26#include "xfs_health.h"
27
28/* ----- Kernel only functions below ----- */
29int
30xfs_readlink_bmap_ilocked(
31 struct xfs_inode *ip,
32 char *link)
33{
34 struct xfs_mount *mp = ip->i_mount;
35 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
36 struct xfs_buf *bp;
37 xfs_daddr_t d;
38 char *cur_chunk;
39 int pathlen = ip->i_disk_size;
40 int nmaps = XFS_SYMLINK_MAPS;
41 int byte_cnt;
42 int n;
43 int error = 0;
44 int fsblocks = 0;
45 int offset;
46
47 ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
48
49 fsblocks = xfs_symlink_blocks(mp, pathlen);
50 error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
51 if (error)
52 goto out;
53
54 offset = 0;
55 for (n = 0; n < nmaps; n++) {
56 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
57 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
58
59 error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
60 &bp, &xfs_symlink_buf_ops);
61 if (error)
62 return error;
63 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
64 if (pathlen < byte_cnt)
65 byte_cnt = pathlen;
66
67 cur_chunk = bp->b_addr;
68 if (xfs_has_crc(mp)) {
69 if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
70 byte_cnt, bp)) {
71 error = -EFSCORRUPTED;
72 xfs_alert(mp,
73"symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
74 offset, byte_cnt, ip->i_ino);
75 xfs_buf_relse(bp);
76 goto out;
77
78 }
79
80 cur_chunk += sizeof(struct xfs_dsymlink_hdr);
81 }
82
83 memcpy(link + offset, cur_chunk, byte_cnt);
84
85 pathlen -= byte_cnt;
86 offset += byte_cnt;
87
88 xfs_buf_relse(bp);
89 }
90 ASSERT(pathlen == 0);
91
92 link[ip->i_disk_size] = '\0';
93 error = 0;
94
95 out:
96 return error;
97}
98
99int
100xfs_readlink(
101 struct xfs_inode *ip,
102 char *link)
103{
104 struct xfs_mount *mp = ip->i_mount;
105 xfs_fsize_t pathlen;
106 int error = -EFSCORRUPTED;
107
108 trace_xfs_readlink(ip);
109
110 if (xfs_is_shutdown(mp))
111 return -EIO;
112 if (xfs_ifork_zapped(ip, XFS_DATA_FORK))
113 return -EIO;
114
115 xfs_ilock(ip, XFS_ILOCK_SHARED);
116
117 pathlen = ip->i_disk_size;
118 if (!pathlen)
119 goto out;
120
121 if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {
122 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
123 __func__, (unsigned long long) ip->i_ino,
124 (long long) pathlen);
125 ASSERT(0);
126 goto out;
127 }
128
129 if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
130 /*
131 * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED
132 * if if_data is junk.
133 */
134 if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_data))
135 goto out;
136
137 memcpy(link, ip->i_df.if_data, pathlen + 1);
138 error = 0;
139 } else {
140 error = xfs_readlink_bmap_ilocked(ip, link);
141 }
142
143 out:
144 xfs_iunlock(ip, XFS_ILOCK_SHARED);
145 return error;
146}
147
148int
149xfs_symlink(
150 struct mnt_idmap *idmap,
151 struct xfs_inode *dp,
152 struct xfs_name *link_name,
153 const char *target_path,
154 umode_t mode,
155 struct xfs_inode **ipp)
156{
157 struct xfs_mount *mp = dp->i_mount;
158 struct xfs_trans *tp = NULL;
159 struct xfs_inode *ip = NULL;
160 int error = 0;
161 int pathlen;
162 bool unlock_dp_on_error = false;
163 xfs_fileoff_t first_fsb;
164 xfs_filblks_t fs_blocks;
165 int nmaps;
166 struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
167 xfs_daddr_t d;
168 const char *cur_chunk;
169 int byte_cnt;
170 int n;
171 struct xfs_buf *bp;
172 prid_t prid;
173 struct xfs_dquot *udqp = NULL;
174 struct xfs_dquot *gdqp = NULL;
175 struct xfs_dquot *pdqp = NULL;
176 uint resblks;
177 xfs_ino_t ino;
178
179 *ipp = NULL;
180
181 trace_xfs_symlink(dp, link_name);
182
183 if (xfs_is_shutdown(mp))
184 return -EIO;
185
186 /*
187 * Check component lengths of the target path name.
188 */
189 pathlen = strlen(target_path);
190 if (pathlen >= XFS_SYMLINK_MAXLEN) /* total string too long */
191 return -ENAMETOOLONG;
192 ASSERT(pathlen > 0);
193
194 prid = xfs_get_initial_prid(dp);
195
196 /*
197 * Make sure that we have allocated dquot(s) on disk.
198 */
199 error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(idmap, &init_user_ns),
200 mapped_fsgid(idmap, &init_user_ns), prid,
201 XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
202 &udqp, &gdqp, &pdqp);
203 if (error)
204 return error;
205
206 /*
207 * The symlink will fit into the inode data fork?
208 * There can't be any attributes so we get the whole variable part.
209 */
210 if (pathlen <= XFS_LITINO(mp))
211 fs_blocks = 0;
212 else
213 fs_blocks = xfs_symlink_blocks(mp, pathlen);
214 resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
215
216 error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,
217 pdqp, resblks, &tp);
218 if (error)
219 goto out_release_dquots;
220
221 xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
222 unlock_dp_on_error = true;
223
224 /*
225 * Check whether the directory allows new symlinks or not.
226 */
227 if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) {
228 error = -EPERM;
229 goto out_trans_cancel;
230 }
231
232 /*
233 * Allocate an inode for the symlink.
234 */
235 error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino);
236 if (!error)
237 error = xfs_init_new_inode(idmap, tp, dp, ino,
238 S_IFLNK | (mode & ~S_IFMT), 1, 0, prid,
239 false, &ip);
240 if (error)
241 goto out_trans_cancel;
242
243 /*
244 * Now we join the directory inode to the transaction. We do not do it
245 * earlier because xfs_dir_ialloc might commit the previous transaction
246 * (and release all the locks). An error from here on will result in
247 * the transaction cancel unlocking dp so don't do it explicitly in the
248 * error path.
249 */
250 xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
251 unlock_dp_on_error = false;
252
253 /*
254 * Also attach the dquot(s) to it, if applicable.
255 */
256 xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
257
258 resblks -= XFS_IALLOC_SPACE_RES(mp);
259 /*
260 * If the symlink will fit into the inode, write it inline.
261 */
262 if (pathlen <= xfs_inode_data_fork_size(ip)) {
263 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
264
265 ip->i_disk_size = pathlen;
266 ip->i_df.if_format = XFS_DINODE_FMT_LOCAL;
267 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
268 } else {
269 int offset;
270
271 first_fsb = 0;
272 nmaps = XFS_SYMLINK_MAPS;
273
274 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
275 XFS_BMAPI_METADATA, resblks, mval, &nmaps);
276 if (error)
277 goto out_trans_cancel;
278
279 resblks -= fs_blocks;
280 ip->i_disk_size = pathlen;
281 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
282
283 cur_chunk = target_path;
284 offset = 0;
285 for (n = 0; n < nmaps; n++) {
286 char *buf;
287
288 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
289 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
290 error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
291 BTOBB(byte_cnt), 0, &bp);
292 if (error)
293 goto out_trans_cancel;
294 bp->b_ops = &xfs_symlink_buf_ops;
295
296 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
297 byte_cnt = min(byte_cnt, pathlen);
298
299 buf = bp->b_addr;
300 buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
301 byte_cnt, bp);
302
303 memcpy(buf, cur_chunk, byte_cnt);
304
305 cur_chunk += byte_cnt;
306 pathlen -= byte_cnt;
307 offset += byte_cnt;
308
309 xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
310 xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
311 (char *)bp->b_addr);
312 }
313 ASSERT(pathlen == 0);
314 }
315 i_size_write(VFS_I(ip), ip->i_disk_size);
316
317 /*
318 * Create the directory entry for the symlink.
319 */
320 error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
321 if (error)
322 goto out_trans_cancel;
323 xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
324 xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
325
326 /*
327 * If this is a synchronous mount, make sure that the
328 * symlink transaction goes to disk before returning to
329 * the user.
330 */
331 if (xfs_has_wsync(mp) || xfs_has_dirsync(mp))
332 xfs_trans_set_sync(tp);
333
334 error = xfs_trans_commit(tp);
335 if (error)
336 goto out_release_inode;
337
338 xfs_qm_dqrele(udqp);
339 xfs_qm_dqrele(gdqp);
340 xfs_qm_dqrele(pdqp);
341
342 *ipp = ip;
343 return 0;
344
345out_trans_cancel:
346 xfs_trans_cancel(tp);
347out_release_inode:
348 /*
349 * Wait until after the current transaction is aborted to finish the
350 * setup of the inode and release the inode. This prevents recursive
351 * transactions and deadlocks from xfs_inactive.
352 */
353 if (ip) {
354 xfs_finish_inode_setup(ip);
355 xfs_irele(ip);
356 }
357out_release_dquots:
358 xfs_qm_dqrele(udqp);
359 xfs_qm_dqrele(gdqp);
360 xfs_qm_dqrele(pdqp);
361
362 if (unlock_dp_on_error)
363 xfs_iunlock(dp, XFS_ILOCK_EXCL);
364 return error;
365}
366
367/*
368 * Free a symlink that has blocks associated with it.
369 *
370 * Note: zero length symlinks are not allowed to exist. When we set the size to
371 * zero, also change it to a regular file so that it does not get written to
372 * disk as a zero length symlink. The inode is on the unlinked list already, so
373 * userspace cannot find this inode anymore, so this change is not user visible
374 * but allows us to catch corrupt zero-length symlinks in the verifiers.
375 */
376STATIC int
377xfs_inactive_symlink_rmt(
378 struct xfs_inode *ip)
379{
380 struct xfs_buf *bp;
381 int done;
382 int error;
383 int i;
384 xfs_mount_t *mp;
385 xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
386 int nmaps;
387 int size;
388 xfs_trans_t *tp;
389
390 mp = ip->i_mount;
391 ASSERT(!xfs_need_iread_extents(&ip->i_df));
392 /*
393 * We're freeing a symlink that has some
394 * blocks allocated to it. Free the
395 * blocks here. We know that we've got
396 * either 1 or 2 extents and that we can
397 * free them all in one bunmapi call.
398 */
399 ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2);
400
401 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
402 if (error)
403 return error;
404
405 xfs_ilock(ip, XFS_ILOCK_EXCL);
406 xfs_trans_ijoin(tp, ip, 0);
407
408 /*
409 * Lock the inode, fix the size, turn it into a regular file and join it
410 * to the transaction. Hold it so in the normal path, we still have it
411 * locked for the second transaction. In the error paths we need it
412 * held so the cancel won't rele it, see below.
413 */
414 size = (int)ip->i_disk_size;
415 ip->i_disk_size = 0;
416 VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;
417 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
418 /*
419 * Find the block(s) so we can inval and unmap them.
420 */
421 done = 0;
422 nmaps = ARRAY_SIZE(mval);
423 error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
424 mval, &nmaps, 0);
425 if (error)
426 goto error_trans_cancel;
427 /*
428 * Invalidate the block(s). No validation is done.
429 */
430 for (i = 0; i < nmaps; i++) {
431 error = xfs_trans_get_buf(tp, mp->m_ddev_targp,
432 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
433 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0,
434 &bp);
435 if (error)
436 goto error_trans_cancel;
437 xfs_trans_binval(tp, bp);
438 }
439 /*
440 * Unmap the dead block(s) to the dfops.
441 */
442 error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done);
443 if (error)
444 goto error_trans_cancel;
445 ASSERT(done);
446
447 /*
448 * Commit the transaction. This first logs the EFI and the inode, then
449 * rolls and commits the transaction that frees the extents.
450 */
451 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
452 error = xfs_trans_commit(tp);
453 if (error) {
454 ASSERT(xfs_is_shutdown(mp));
455 goto error_unlock;
456 }
457
458 /*
459 * Remove the memory for extent descriptions (just bookkeeping).
460 */
461 if (ip->i_df.if_bytes)
462 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
463 ASSERT(ip->i_df.if_bytes == 0);
464
465 xfs_iunlock(ip, XFS_ILOCK_EXCL);
466 return 0;
467
468error_trans_cancel:
469 xfs_trans_cancel(tp);
470error_unlock:
471 xfs_iunlock(ip, XFS_ILOCK_EXCL);
472 return error;
473}
474
475/*
476 * xfs_inactive_symlink - free a symlink
477 */
478int
479xfs_inactive_symlink(
480 struct xfs_inode *ip)
481{
482 struct xfs_mount *mp = ip->i_mount;
483 int pathlen;
484
485 trace_xfs_inactive_symlink(ip);
486
487 if (xfs_is_shutdown(mp))
488 return -EIO;
489
490 xfs_ilock(ip, XFS_ILOCK_EXCL);
491 pathlen = (int)ip->i_disk_size;
492 ASSERT(pathlen);
493
494 if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {
495 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
496 __func__, (unsigned long long)ip->i_ino, pathlen);
497 xfs_iunlock(ip, XFS_ILOCK_EXCL);
498 ASSERT(0);
499 return -EFSCORRUPTED;
500 }
501
502 /*
503 * Inline fork state gets removed by xfs_difree() so we have nothing to
504 * do here in that case.
505 */
506 if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
507 xfs_iunlock(ip, XFS_ILOCK_EXCL);
508 return 0;
509 }
510
511 xfs_iunlock(ip, XFS_ILOCK_EXCL);
512
513 /* remove the remote symlink */
514 return xfs_inactive_symlink_rmt(ip);
515}