ARM64: DTS: Add rk3399-firefly uart4 device, node as /dev/ttyS1
[firefly-linux-kernel-4.4.55.git] / fs / xfs / xfs_symlink.c
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_dir2.h"
30 #include "xfs_inode.h"
31 #include "xfs_ialloc.h"
32 #include "xfs_alloc.h"
33 #include "xfs_bmap.h"
34 #include "xfs_bmap_btree.h"
35 #include "xfs_bmap_util.h"
36 #include "xfs_error.h"
37 #include "xfs_quota.h"
38 #include "xfs_trans_space.h"
39 #include "xfs_trace.h"
40 #include "xfs_symlink.h"
41 #include "xfs_trans.h"
42 #include "xfs_log.h"
43
44 /* ----- Kernel only functions below ----- */
45 STATIC int
46 xfs_readlink_bmap(
47         struct xfs_inode        *ip,
48         char                    *link)
49 {
50         struct xfs_mount        *mp = ip->i_mount;
51         struct xfs_bmbt_irec    mval[XFS_SYMLINK_MAPS];
52         struct xfs_buf          *bp;
53         xfs_daddr_t             d;
54         char                    *cur_chunk;
55         int                     pathlen = ip->i_d.di_size;
56         int                     nmaps = XFS_SYMLINK_MAPS;
57         int                     byte_cnt;
58         int                     n;
59         int                     error = 0;
60         int                     fsblocks = 0;
61         int                     offset;
62
63         fsblocks = xfs_symlink_blocks(mp, pathlen);
64         error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
65         if (error)
66                 goto out;
67
68         offset = 0;
69         for (n = 0; n < nmaps; n++) {
70                 d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
71                 byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
72
73                 bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
74                                   &xfs_symlink_buf_ops);
75                 if (!bp)
76                         return -ENOMEM;
77                 error = bp->b_error;
78                 if (error) {
79                         xfs_buf_ioerror_alert(bp, __func__);
80                         xfs_buf_relse(bp);
81
82                         /* bad CRC means corrupted metadata */
83                         if (error == -EFSBADCRC)
84                                 error = -EFSCORRUPTED;
85                         goto out;
86                 }
87                 byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
88                 if (pathlen < byte_cnt)
89                         byte_cnt = pathlen;
90
91                 cur_chunk = bp->b_addr;
92                 if (xfs_sb_version_hascrc(&mp->m_sb)) {
93                         if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
94                                                         byte_cnt, bp)) {
95                                 error = -EFSCORRUPTED;
96                                 xfs_alert(mp,
97 "symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
98                                         offset, byte_cnt, ip->i_ino);
99                                 xfs_buf_relse(bp);
100                                 goto out;
101
102                         }
103
104                         cur_chunk += sizeof(struct xfs_dsymlink_hdr);
105                 }
106
107                 memcpy(link + offset, cur_chunk, byte_cnt);
108
109                 pathlen -= byte_cnt;
110                 offset += byte_cnt;
111
112                 xfs_buf_relse(bp);
113         }
114         ASSERT(pathlen == 0);
115
116         link[ip->i_d.di_size] = '\0';
117         error = 0;
118
119  out:
120         return error;
121 }
122
123 int
124 xfs_readlink(
125         struct xfs_inode *ip,
126         char            *link)
127 {
128         struct xfs_mount *mp = ip->i_mount;
129         xfs_fsize_t     pathlen;
130         int             error = 0;
131
132         trace_xfs_readlink(ip);
133
134         if (XFS_FORCED_SHUTDOWN(mp))
135                 return -EIO;
136
137         xfs_ilock(ip, XFS_ILOCK_SHARED);
138
139         pathlen = ip->i_d.di_size;
140         if (!pathlen)
141                 goto out;
142
143         if (pathlen < 0 || pathlen > MAXPATHLEN) {
144                 xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
145                          __func__, (unsigned long long) ip->i_ino,
146                          (long long) pathlen);
147                 ASSERT(0);
148                 error = -EFSCORRUPTED;
149                 goto out;
150         }
151
152
153         if (ip->i_df.if_flags & XFS_IFINLINE) {
154                 memcpy(link, ip->i_df.if_u1.if_data, pathlen);
155                 link[pathlen] = '\0';
156         } else {
157                 error = xfs_readlink_bmap(ip, link);
158         }
159
160  out:
161         xfs_iunlock(ip, XFS_ILOCK_SHARED);
162         return error;
163 }
164
165 int
166 xfs_symlink(
167         struct xfs_inode        *dp,
168         struct xfs_name         *link_name,
169         const char              *target_path,
170         umode_t                 mode,
171         struct xfs_inode        **ipp)
172 {
173         struct xfs_mount        *mp = dp->i_mount;
174         struct xfs_trans        *tp = NULL;
175         struct xfs_inode        *ip = NULL;
176         int                     error = 0;
177         int                     pathlen;
178         struct xfs_bmap_free    free_list;
179         xfs_fsblock_t           first_block;
180         bool                    unlock_dp_on_error = false;
181         int                     committed;
182         xfs_fileoff_t           first_fsb;
183         xfs_filblks_t           fs_blocks;
184         int                     nmaps;
185         struct xfs_bmbt_irec    mval[XFS_SYMLINK_MAPS];
186         xfs_daddr_t             d;
187         const char              *cur_chunk;
188         int                     byte_cnt;
189         int                     n;
190         xfs_buf_t               *bp;
191         prid_t                  prid;
192         struct xfs_dquot        *udqp = NULL;
193         struct xfs_dquot        *gdqp = NULL;
194         struct xfs_dquot        *pdqp = NULL;
195         uint                    resblks;
196
197         *ipp = NULL;
198
199         trace_xfs_symlink(dp, link_name);
200
201         if (XFS_FORCED_SHUTDOWN(mp))
202                 return -EIO;
203
204         /*
205          * Check component lengths of the target path name.
206          */
207         pathlen = strlen(target_path);
208         if (pathlen >= MAXPATHLEN)      /* total string too long */
209                 return -ENAMETOOLONG;
210
211         udqp = gdqp = NULL;
212         prid = xfs_get_initial_prid(dp);
213
214         /*
215          * Make sure that we have allocated dquot(s) on disk.
216          */
217         error = xfs_qm_vop_dqalloc(dp,
218                         xfs_kuid_to_uid(current_fsuid()),
219                         xfs_kgid_to_gid(current_fsgid()), prid,
220                         XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
221                         &udqp, &gdqp, &pdqp);
222         if (error)
223                 return error;
224
225         tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
226         /*
227          * The symlink will fit into the inode data fork?
228          * There can't be any attributes so we get the whole variable part.
229          */
230         if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
231                 fs_blocks = 0;
232         else
233                 fs_blocks = xfs_symlink_blocks(mp, pathlen);
234         resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
235         error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0);
236         if (error == -ENOSPC && fs_blocks == 0) {
237                 resblks = 0;
238                 error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0);
239         }
240         if (error)
241                 goto out_trans_cancel;
242
243         xfs_ilock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL |
244                       XFS_IOLOCK_PARENT | XFS_ILOCK_PARENT);
245         unlock_dp_on_error = true;
246
247         /*
248          * Check whether the directory allows new symlinks or not.
249          */
250         if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
251                 error = -EPERM;
252                 goto out_trans_cancel;
253         }
254
255         /*
256          * Reserve disk quota : blocks and inode.
257          */
258         error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
259                                                 pdqp, resblks, 1, 0);
260         if (error)
261                 goto out_trans_cancel;
262
263         /*
264          * Check for ability to enter directory entry, if no space reserved.
265          */
266         if (!resblks) {
267                 error = xfs_dir_canenter(tp, dp, link_name);
268                 if (error)
269                         goto out_trans_cancel;
270         }
271         /*
272          * Initialize the bmap freelist prior to calling either
273          * bmapi or the directory create code.
274          */
275         xfs_bmap_init(&free_list, &first_block);
276
277         /*
278          * Allocate an inode for the symlink.
279          */
280         error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
281                                prid, resblks > 0, &ip, NULL);
282         if (error)
283                 goto out_trans_cancel;
284
285         /*
286          * Now we join the directory inode to the transaction.  We do not do it
287          * earlier because xfs_dir_ialloc might commit the previous transaction
288          * (and release all the locks).  An error from here on will result in
289          * the transaction cancel unlocking dp so don't do it explicitly in the
290          * error path.
291          */
292         xfs_trans_ijoin(tp, dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
293         unlock_dp_on_error = false;
294
295         /*
296          * Also attach the dquot(s) to it, if applicable.
297          */
298         xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
299
300         if (resblks)
301                 resblks -= XFS_IALLOC_SPACE_RES(mp);
302         /*
303          * If the symlink will fit into the inode, write it inline.
304          */
305         if (pathlen <= XFS_IFORK_DSIZE(ip)) {
306                 xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
307                 memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
308                 ip->i_d.di_size = pathlen;
309
310                 /*
311                  * The inode was initially created in extent format.
312                  */
313                 ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
314                 ip->i_df.if_flags |= XFS_IFINLINE;
315
316                 ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
317                 xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
318
319         } else {
320                 int     offset;
321
322                 first_fsb = 0;
323                 nmaps = XFS_SYMLINK_MAPS;
324
325                 error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
326                                   XFS_BMAPI_METADATA, &first_block, resblks,
327                                   mval, &nmaps, &free_list);
328                 if (error)
329                         goto out_bmap_cancel;
330
331                 if (resblks)
332                         resblks -= fs_blocks;
333                 ip->i_d.di_size = pathlen;
334                 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
335
336                 cur_chunk = target_path;
337                 offset = 0;
338                 for (n = 0; n < nmaps; n++) {
339                         char    *buf;
340
341                         d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
342                         byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
343                         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
344                                                BTOBB(byte_cnt), 0);
345                         if (!bp) {
346                                 error = -ENOMEM;
347                                 goto out_bmap_cancel;
348                         }
349                         bp->b_ops = &xfs_symlink_buf_ops;
350
351                         byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
352                         byte_cnt = min(byte_cnt, pathlen);
353
354                         buf = bp->b_addr;
355                         buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
356                                                    byte_cnt, bp);
357
358                         memcpy(buf, cur_chunk, byte_cnt);
359
360                         cur_chunk += byte_cnt;
361                         pathlen -= byte_cnt;
362                         offset += byte_cnt;
363
364                         xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
365                         xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
366                                                         (char *)bp->b_addr);
367                 }
368                 ASSERT(pathlen == 0);
369         }
370
371         /*
372          * Create the directory entry for the symlink.
373          */
374         error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
375                                         &first_block, &free_list, resblks);
376         if (error)
377                 goto out_bmap_cancel;
378         xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
379         xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
380
381         /*
382          * If this is a synchronous mount, make sure that the
383          * symlink transaction goes to disk before returning to
384          * the user.
385          */
386         if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
387                 xfs_trans_set_sync(tp);
388         }
389
390         error = xfs_bmap_finish(&tp, &free_list, &committed);
391         if (error)
392                 goto out_bmap_cancel;
393
394         error = xfs_trans_commit(tp);
395         if (error)
396                 goto out_release_inode;
397
398         xfs_qm_dqrele(udqp);
399         xfs_qm_dqrele(gdqp);
400         xfs_qm_dqrele(pdqp);
401
402         *ipp = ip;
403         return 0;
404
405 out_bmap_cancel:
406         xfs_bmap_cancel(&free_list);
407 out_trans_cancel:
408         xfs_trans_cancel(tp);
409 out_release_inode:
410         /*
411          * Wait until after the current transaction is aborted to finish the
412          * setup of the inode and release the inode.  This prevents recursive
413          * transactions and deadlocks from xfs_inactive.
414          */
415         if (ip) {
416                 xfs_finish_inode_setup(ip);
417                 IRELE(ip);
418         }
419
420         xfs_qm_dqrele(udqp);
421         xfs_qm_dqrele(gdqp);
422         xfs_qm_dqrele(pdqp);
423
424         if (unlock_dp_on_error)
425                 xfs_iunlock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
426         return error;
427 }
428
429 /*
430  * Free a symlink that has blocks associated with it.
431  */
432 STATIC int
433 xfs_inactive_symlink_rmt(
434         struct xfs_inode *ip)
435 {
436         xfs_buf_t       *bp;
437         int             committed;
438         int             done;
439         int             error;
440         xfs_fsblock_t   first_block;
441         xfs_bmap_free_t free_list;
442         int             i;
443         xfs_mount_t     *mp;
444         xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
445         int             nmaps;
446         int             size;
447         xfs_trans_t     *tp;
448
449         mp = ip->i_mount;
450         ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
451         /*
452          * We're freeing a symlink that has some
453          * blocks allocated to it.  Free the
454          * blocks here.  We know that we've got
455          * either 1 or 2 extents and that we can
456          * free them all in one bunmapi call.
457          */
458         ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
459
460         tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
461         error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
462         if (error) {
463                 xfs_trans_cancel(tp);
464                 return error;
465         }
466
467         xfs_ilock(ip, XFS_ILOCK_EXCL);
468         xfs_trans_ijoin(tp, ip, 0);
469
470         /*
471          * Lock the inode, fix the size, and join it to the transaction.
472          * Hold it so in the normal path, we still have it locked for
473          * the second transaction.  In the error paths we need it
474          * held so the cancel won't rele it, see below.
475          */
476         size = (int)ip->i_d.di_size;
477         ip->i_d.di_size = 0;
478         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
479         /*
480          * Find the block(s) so we can inval and unmap them.
481          */
482         done = 0;
483         xfs_bmap_init(&free_list, &first_block);
484         nmaps = ARRAY_SIZE(mval);
485         error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
486                                 mval, &nmaps, 0);
487         if (error)
488                 goto error_trans_cancel;
489         /*
490          * Invalidate the block(s). No validation is done.
491          */
492         for (i = 0; i < nmaps; i++) {
493                 bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
494                         XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
495                         XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
496                 if (!bp) {
497                         error = -ENOMEM;
498                         goto error_bmap_cancel;
499                 }
500                 xfs_trans_binval(tp, bp);
501         }
502         /*
503          * Unmap the dead block(s) to the free_list.
504          */
505         error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps,
506                             &first_block, &free_list, &done);
507         if (error)
508                 goto error_bmap_cancel;
509         ASSERT(done);
510         /*
511          * Commit the first transaction.  This logs the EFI and the inode.
512          */
513         error = xfs_bmap_finish(&tp, &free_list, &committed);
514         if (error)
515                 goto error_bmap_cancel;
516         /*
517          * The transaction must have been committed, since there were
518          * actually extents freed by xfs_bunmapi.  See xfs_bmap_finish.
519          * The new tp has the extent freeing and EFDs.
520          */
521         ASSERT(committed);
522         /*
523          * The first xact was committed, so add the inode to the new one.
524          * Mark it dirty so it will be logged and moved forward in the log as
525          * part of every commit.
526          */
527         xfs_trans_ijoin(tp, ip, 0);
528         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
529         /*
530          * Commit the transaction containing extent freeing and EFDs.
531          */
532         error = xfs_trans_commit(tp);
533         if (error) {
534                 ASSERT(XFS_FORCED_SHUTDOWN(mp));
535                 goto error_unlock;
536         }
537
538         /*
539          * Remove the memory for extent descriptions (just bookkeeping).
540          */
541         if (ip->i_df.if_bytes)
542                 xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
543         ASSERT(ip->i_df.if_bytes == 0);
544
545         xfs_iunlock(ip, XFS_ILOCK_EXCL);
546         return 0;
547
548 error_bmap_cancel:
549         xfs_bmap_cancel(&free_list);
550 error_trans_cancel:
551         xfs_trans_cancel(tp);
552 error_unlock:
553         xfs_iunlock(ip, XFS_ILOCK_EXCL);
554         return error;
555 }
556
557 /*
558  * xfs_inactive_symlink - free a symlink
559  */
560 int
561 xfs_inactive_symlink(
562         struct xfs_inode        *ip)
563 {
564         struct xfs_mount        *mp = ip->i_mount;
565         int                     pathlen;
566
567         trace_xfs_inactive_symlink(ip);
568
569         if (XFS_FORCED_SHUTDOWN(mp))
570                 return -EIO;
571
572         xfs_ilock(ip, XFS_ILOCK_EXCL);
573
574         /*
575          * Zero length symlinks _can_ exist.
576          */
577         pathlen = (int)ip->i_d.di_size;
578         if (!pathlen) {
579                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
580                 return 0;
581         }
582
583         if (pathlen < 0 || pathlen > MAXPATHLEN) {
584                 xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
585                          __func__, (unsigned long long)ip->i_ino, pathlen);
586                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
587                 ASSERT(0);
588                 return -EFSCORRUPTED;
589         }
590
591         if (ip->i_df.if_flags & XFS_IFINLINE) {
592                 if (ip->i_df.if_bytes > 0) 
593                         xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
594                                           XFS_DATA_FORK);
595                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
596                 ASSERT(ip->i_df.if_bytes == 0);
597                 return 0;
598         }
599
600         xfs_iunlock(ip, XFS_ILOCK_EXCL);
601
602         /* remove the remote symlink */
603         return xfs_inactive_symlink_rmt(ip);
604 }