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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}