ksmbd: remove unneeded check_context_err
[linux-2.6-microblaze.git] / fs / xfs / xfs_symlink.c
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
25 /* ----- Kernel only functions below ----- */
26 int
27 xfs_readlink_bmap_ilocked(
28         struct xfs_inode        *ip,
29         char                    *link)
30 {
31         struct xfs_mount        *mp = ip->i_mount;
32         struct xfs_bmbt_irec    mval[XFS_SYMLINK_MAPS];
33         struct xfs_buf          *bp;
34         xfs_daddr_t             d;
35         char                    *cur_chunk;
36         int                     pathlen = ip->i_disk_size;
37         int                     nmaps = XFS_SYMLINK_MAPS;
38         int                     byte_cnt;
39         int                     n;
40         int                     error = 0;
41         int                     fsblocks = 0;
42         int                     offset;
43
44         ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
45
46         fsblocks = xfs_symlink_blocks(mp, pathlen);
47         error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
48         if (error)
49                 goto out;
50
51         offset = 0;
52         for (n = 0; n < nmaps; n++) {
53                 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
54                 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
55
56                 error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
57                                 &bp, &xfs_symlink_buf_ops);
58                 if (error)
59                         return error;
60                 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
61                 if (pathlen < byte_cnt)
62                         byte_cnt = pathlen;
63
64                 cur_chunk = bp->b_addr;
65                 if (xfs_sb_version_hascrc(&mp->m_sb)) {
66                         if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
67                                                         byte_cnt, bp)) {
68                                 error = -EFSCORRUPTED;
69                                 xfs_alert(mp,
70 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
71                                         offset, byte_cnt, ip->i_ino);
72                                 xfs_buf_relse(bp);
73                                 goto out;
74
75                         }
76
77                         cur_chunk += sizeof(struct xfs_dsymlink_hdr);
78                 }
79
80                 memcpy(link + offset, cur_chunk, byte_cnt);
81
82                 pathlen -= byte_cnt;
83                 offset += byte_cnt;
84
85                 xfs_buf_relse(bp);
86         }
87         ASSERT(pathlen == 0);
88
89         link[ip->i_disk_size] = '\0';
90         error = 0;
91
92  out:
93         return error;
94 }
95
96 int
97 xfs_readlink(
98         struct xfs_inode *ip,
99         char            *link)
100 {
101         struct xfs_mount *mp = ip->i_mount;
102         xfs_fsize_t     pathlen;
103         int             error = 0;
104
105         trace_xfs_readlink(ip);
106
107         ASSERT(ip->i_df.if_format != XFS_DINODE_FMT_LOCAL);
108
109         if (XFS_FORCED_SHUTDOWN(mp))
110                 return -EIO;
111
112         xfs_ilock(ip, XFS_ILOCK_SHARED);
113
114         pathlen = ip->i_disk_size;
115         if (!pathlen)
116                 goto out;
117
118         if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {
119                 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
120                          __func__, (unsigned long long) ip->i_ino,
121                          (long long) pathlen);
122                 ASSERT(0);
123                 error = -EFSCORRUPTED;
124                 goto out;
125         }
126
127
128         error = xfs_readlink_bmap_ilocked(ip, link);
129
130  out:
131         xfs_iunlock(ip, XFS_ILOCK_SHARED);
132         return error;
133 }
134
135 int
136 xfs_symlink(
137         struct user_namespace   *mnt_userns,
138         struct xfs_inode        *dp,
139         struct xfs_name         *link_name,
140         const char              *target_path,
141         umode_t                 mode,
142         struct xfs_inode        **ipp)
143 {
144         struct xfs_mount        *mp = dp->i_mount;
145         struct xfs_trans        *tp = NULL;
146         struct xfs_inode        *ip = NULL;
147         int                     error = 0;
148         int                     pathlen;
149         bool                    unlock_dp_on_error = false;
150         xfs_fileoff_t           first_fsb;
151         xfs_filblks_t           fs_blocks;
152         int                     nmaps;
153         struct xfs_bmbt_irec    mval[XFS_SYMLINK_MAPS];
154         xfs_daddr_t             d;
155         const char              *cur_chunk;
156         int                     byte_cnt;
157         int                     n;
158         struct xfs_buf          *bp;
159         prid_t                  prid;
160         struct xfs_dquot        *udqp = NULL;
161         struct xfs_dquot        *gdqp = NULL;
162         struct xfs_dquot        *pdqp = NULL;
163         uint                    resblks;
164
165         *ipp = NULL;
166
167         trace_xfs_symlink(dp, link_name);
168
169         if (XFS_FORCED_SHUTDOWN(mp))
170                 return -EIO;
171
172         /*
173          * Check component lengths of the target path name.
174          */
175         pathlen = strlen(target_path);
176         if (pathlen >= XFS_SYMLINK_MAXLEN)      /* total string too long */
177                 return -ENAMETOOLONG;
178         ASSERT(pathlen > 0);
179
180         prid = xfs_get_initial_prid(dp);
181
182         /*
183          * Make sure that we have allocated dquot(s) on disk.
184          */
185         error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns),
186                         mapped_fsgid(mnt_userns), prid,
187                         XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
188                         &udqp, &gdqp, &pdqp);
189         if (error)
190                 return error;
191
192         /*
193          * The symlink will fit into the inode data fork?
194          * There can't be any attributes so we get the whole variable part.
195          */
196         if (pathlen <= XFS_LITINO(mp))
197                 fs_blocks = 0;
198         else
199                 fs_blocks = xfs_symlink_blocks(mp, pathlen);
200         resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
201
202         error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,
203                         pdqp, resblks, &tp);
204         if (error)
205                 goto out_release_dquots;
206
207         xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
208         unlock_dp_on_error = true;
209
210         /*
211          * Check whether the directory allows new symlinks or not.
212          */
213         if (dp->i_diflags & XFS_DIFLAG_NOSYMLINKS) {
214                 error = -EPERM;
215                 goto out_trans_cancel;
216         }
217
218         error = xfs_iext_count_may_overflow(dp, XFS_DATA_FORK,
219                         XFS_IEXT_DIR_MANIP_CNT(mp));
220         if (error)
221                 goto out_trans_cancel;
222
223         /*
224          * Allocate an inode for the symlink.
225          */
226         error = xfs_dir_ialloc(mnt_userns, &tp, dp, S_IFLNK | (mode & ~S_IFMT),
227                                1, 0, prid, false, &ip);
228         if (error)
229                 goto out_trans_cancel;
230
231         /*
232          * Now we join the directory inode to the transaction.  We do not do it
233          * earlier because xfs_dir_ialloc might commit the previous transaction
234          * (and release all the locks).  An error from here on will result in
235          * the transaction cancel unlocking dp so don't do it explicitly in the
236          * error path.
237          */
238         xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
239         unlock_dp_on_error = false;
240
241         /*
242          * Also attach the dquot(s) to it, if applicable.
243          */
244         xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
245
246         resblks -= XFS_IALLOC_SPACE_RES(mp);
247         /*
248          * If the symlink will fit into the inode, write it inline.
249          */
250         if (pathlen <= XFS_IFORK_DSIZE(ip)) {
251                 xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
252
253                 ip->i_disk_size = pathlen;
254                 ip->i_df.if_format = XFS_DINODE_FMT_LOCAL;
255                 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
256         } else {
257                 int     offset;
258
259                 first_fsb = 0;
260                 nmaps = XFS_SYMLINK_MAPS;
261
262                 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
263                                   XFS_BMAPI_METADATA, resblks, mval, &nmaps);
264                 if (error)
265                         goto out_trans_cancel;
266
267                 resblks -= fs_blocks;
268                 ip->i_disk_size = pathlen;
269                 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
270
271                 cur_chunk = target_path;
272                 offset = 0;
273                 for (n = 0; n < nmaps; n++) {
274                         char    *buf;
275
276                         d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
277                         byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
278                         error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
279                                                BTOBB(byte_cnt), 0, &bp);
280                         if (error)
281                                 goto out_trans_cancel;
282                         bp->b_ops = &xfs_symlink_buf_ops;
283
284                         byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
285                         byte_cnt = min(byte_cnt, pathlen);
286
287                         buf = bp->b_addr;
288                         buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
289                                                    byte_cnt, bp);
290
291                         memcpy(buf, cur_chunk, byte_cnt);
292
293                         cur_chunk += byte_cnt;
294                         pathlen -= byte_cnt;
295                         offset += byte_cnt;
296
297                         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
298                         xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
299                                                         (char *)bp->b_addr);
300                 }
301                 ASSERT(pathlen == 0);
302         }
303         i_size_write(VFS_I(ip), ip->i_disk_size);
304
305         /*
306          * Create the directory entry for the symlink.
307          */
308         error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
309         if (error)
310                 goto out_trans_cancel;
311         xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
312         xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
313
314         /*
315          * If this is a synchronous mount, make sure that the
316          * symlink transaction goes to disk before returning to
317          * the user.
318          */
319         if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
320                 xfs_trans_set_sync(tp);
321         }
322
323         error = xfs_trans_commit(tp);
324         if (error)
325                 goto out_release_inode;
326
327         xfs_qm_dqrele(udqp);
328         xfs_qm_dqrele(gdqp);
329         xfs_qm_dqrele(pdqp);
330
331         *ipp = ip;
332         return 0;
333
334 out_trans_cancel:
335         xfs_trans_cancel(tp);
336 out_release_inode:
337         /*
338          * Wait until after the current transaction is aborted to finish the
339          * setup of the inode and release the inode.  This prevents recursive
340          * transactions and deadlocks from xfs_inactive.
341          */
342         if (ip) {
343                 xfs_finish_inode_setup(ip);
344                 xfs_irele(ip);
345         }
346 out_release_dquots:
347         xfs_qm_dqrele(udqp);
348         xfs_qm_dqrele(gdqp);
349         xfs_qm_dqrele(pdqp);
350
351         if (unlock_dp_on_error)
352                 xfs_iunlock(dp, XFS_ILOCK_EXCL);
353         return error;
354 }
355
356 /*
357  * Free a symlink that has blocks associated with it.
358  *
359  * Note: zero length symlinks are not allowed to exist. When we set the size to
360  * zero, also change it to a regular file so that it does not get written to
361  * disk as a zero length symlink. The inode is on the unlinked list already, so
362  * userspace cannot find this inode anymore, so this change is not user visible
363  * but allows us to catch corrupt zero-length symlinks in the verifiers.
364  */
365 STATIC int
366 xfs_inactive_symlink_rmt(
367         struct xfs_inode *ip)
368 {
369         struct xfs_buf  *bp;
370         int             done;
371         int             error;
372         int             i;
373         xfs_mount_t     *mp;
374         xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
375         int             nmaps;
376         int             size;
377         xfs_trans_t     *tp;
378
379         mp = ip->i_mount;
380         ASSERT(!xfs_need_iread_extents(&ip->i_df));
381         /*
382          * We're freeing a symlink that has some
383          * blocks allocated to it.  Free the
384          * blocks here.  We know that we've got
385          * either 1 or 2 extents and that we can
386          * free them all in one bunmapi call.
387          */
388         ASSERT(ip->i_df.if_nextents > 0 && ip->i_df.if_nextents <= 2);
389
390         error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
391         if (error)
392                 return error;
393
394         xfs_ilock(ip, XFS_ILOCK_EXCL);
395         xfs_trans_ijoin(tp, ip, 0);
396
397         /*
398          * Lock the inode, fix the size, turn it into a regular file and join it
399          * to the transaction.  Hold it so in the normal path, we still have it
400          * locked for the second transaction.  In the error paths we need it
401          * held so the cancel won't rele it, see below.
402          */
403         size = (int)ip->i_disk_size;
404         ip->i_disk_size = 0;
405         VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;
406         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
407         /*
408          * Find the block(s) so we can inval and unmap them.
409          */
410         done = 0;
411         nmaps = ARRAY_SIZE(mval);
412         error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
413                                 mval, &nmaps, 0);
414         if (error)
415                 goto error_trans_cancel;
416         /*
417          * Invalidate the block(s). No validation is done.
418          */
419         for (i = 0; i < nmaps; i++) {
420                 error = xfs_trans_get_buf(tp, mp->m_ddev_targp,
421                                 XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
422                                 XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0,
423                                 &bp);
424                 if (error)
425                         goto error_trans_cancel;
426                 xfs_trans_binval(tp, bp);
427         }
428         /*
429          * Unmap the dead block(s) to the dfops.
430          */
431         error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done);
432         if (error)
433                 goto error_trans_cancel;
434         ASSERT(done);
435
436         /*
437          * Commit the transaction. This first logs the EFI and the inode, then
438          * rolls and commits the transaction that frees the extents.
439          */
440         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
441         error = xfs_trans_commit(tp);
442         if (error) {
443                 ASSERT(XFS_FORCED_SHUTDOWN(mp));
444                 goto error_unlock;
445         }
446
447         /*
448          * Remove the memory for extent descriptions (just bookkeeping).
449          */
450         if (ip->i_df.if_bytes)
451                 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
452         ASSERT(ip->i_df.if_bytes == 0);
453
454         xfs_iunlock(ip, XFS_ILOCK_EXCL);
455         return 0;
456
457 error_trans_cancel:
458         xfs_trans_cancel(tp);
459 error_unlock:
460         xfs_iunlock(ip, XFS_ILOCK_EXCL);
461         return error;
462 }
463
464 /*
465  * xfs_inactive_symlink - free a symlink
466  */
467 int
468 xfs_inactive_symlink(
469         struct xfs_inode        *ip)
470 {
471         struct xfs_mount        *mp = ip->i_mount;
472         int                     pathlen;
473
474         trace_xfs_inactive_symlink(ip);
475
476         if (XFS_FORCED_SHUTDOWN(mp))
477                 return -EIO;
478
479         xfs_ilock(ip, XFS_ILOCK_EXCL);
480         pathlen = (int)ip->i_disk_size;
481         ASSERT(pathlen);
482
483         if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {
484                 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
485                          __func__, (unsigned long long)ip->i_ino, pathlen);
486                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
487                 ASSERT(0);
488                 return -EFSCORRUPTED;
489         }
490
491         /*
492          * Inline fork state gets removed by xfs_difree() so we have nothing to
493          * do here in that case.
494          */
495         if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
496                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
497                 return 0;
498         }
499
500         xfs_iunlock(ip, XFS_ILOCK_EXCL);
501
502         /* remove the remote symlink */
503         return xfs_inactive_symlink_rmt(ip);
504 }