Merge master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6
[linux-2.6] / fs / xfs / linux-2.6 / xfs_lrw.c
1 /*
2  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write the Free Software Foundation,
16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 #include "xfs.h"
19 #include "xfs_fs.h"
20 #include "xfs_bit.h"
21 #include "xfs_log.h"
22 #include "xfs_inum.h"
23 #include "xfs_trans.h"
24 #include "xfs_sb.h"
25 #include "xfs_ag.h"
26 #include "xfs_dir2.h"
27 #include "xfs_alloc.h"
28 #include "xfs_dmapi.h"
29 #include "xfs_quota.h"
30 #include "xfs_mount.h"
31 #include "xfs_bmap_btree.h"
32 #include "xfs_alloc_btree.h"
33 #include "xfs_ialloc_btree.h"
34 #include "xfs_dir2_sf.h"
35 #include "xfs_attr_sf.h"
36 #include "xfs_dinode.h"
37 #include "xfs_inode.h"
38 #include "xfs_bmap.h"
39 #include "xfs_btree.h"
40 #include "xfs_ialloc.h"
41 #include "xfs_rtalloc.h"
42 #include "xfs_error.h"
43 #include "xfs_itable.h"
44 #include "xfs_rw.h"
45 #include "xfs_acl.h"
46 #include "xfs_attr.h"
47 #include "xfs_inode_item.h"
48 #include "xfs_buf_item.h"
49 #include "xfs_utils.h"
50 #include "xfs_iomap.h"
51
52 #include <linux/capability.h>
53 #include <linux/writeback.h>
54
55
56 #if defined(XFS_RW_TRACE)
57 void
58 xfs_rw_enter_trace(
59         int                     tag,
60         xfs_iocore_t            *io,
61         void                    *data,
62         size_t                  segs,
63         loff_t                  offset,
64         int                     ioflags)
65 {
66         xfs_inode_t     *ip = XFS_IO_INODE(io);
67
68         if (ip->i_rwtrace == NULL)
69                 return;
70         ktrace_enter(ip->i_rwtrace,
71                 (void *)(unsigned long)tag,
72                 (void *)ip,
73                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
74                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
75                 (void *)data,
76                 (void *)((unsigned long)segs),
77                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
78                 (void *)((unsigned long)(offset & 0xffffffff)),
79                 (void *)((unsigned long)ioflags),
80                 (void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
81                 (void *)((unsigned long)(io->io_new_size & 0xffffffff)),
82                 (void *)((unsigned long)current_pid()),
83                 (void *)NULL,
84                 (void *)NULL,
85                 (void *)NULL,
86                 (void *)NULL);
87 }
88
89 void
90 xfs_inval_cached_trace(
91         xfs_iocore_t    *io,
92         xfs_off_t       offset,
93         xfs_off_t       len,
94         xfs_off_t       first,
95         xfs_off_t       last)
96 {
97         xfs_inode_t     *ip = XFS_IO_INODE(io);
98
99         if (ip->i_rwtrace == NULL)
100                 return;
101         ktrace_enter(ip->i_rwtrace,
102                 (void *)(__psint_t)XFS_INVAL_CACHED,
103                 (void *)ip,
104                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
105                 (void *)((unsigned long)(offset & 0xffffffff)),
106                 (void *)((unsigned long)((len >> 32) & 0xffffffff)),
107                 (void *)((unsigned long)(len & 0xffffffff)),
108                 (void *)((unsigned long)((first >> 32) & 0xffffffff)),
109                 (void *)((unsigned long)(first & 0xffffffff)),
110                 (void *)((unsigned long)((last >> 32) & 0xffffffff)),
111                 (void *)((unsigned long)(last & 0xffffffff)),
112                 (void *)((unsigned long)current_pid()),
113                 (void *)NULL,
114                 (void *)NULL,
115                 (void *)NULL,
116                 (void *)NULL,
117                 (void *)NULL);
118 }
119 #endif
120
121 /*
122  *      xfs_iozero
123  *
124  *      xfs_iozero clears the specified range of buffer supplied,
125  *      and marks all the affected blocks as valid and modified.  If
126  *      an affected block is not allocated, it will be allocated.  If
127  *      an affected block is not completely overwritten, and is not
128  *      valid before the operation, it will be read from disk before
129  *      being partially zeroed.
130  */
131 STATIC int
132 xfs_iozero(
133         struct inode            *ip,    /* inode                        */
134         loff_t                  pos,    /* offset in file               */
135         size_t                  count)  /* size of data to zero         */
136 {
137         unsigned                bytes;
138         struct page             *page;
139         struct address_space    *mapping;
140         int                     status;
141
142         mapping = ip->i_mapping;
143         do {
144                 unsigned long index, offset;
145
146                 offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
147                 index = pos >> PAGE_CACHE_SHIFT;
148                 bytes = PAGE_CACHE_SIZE - offset;
149                 if (bytes > count)
150                         bytes = count;
151
152                 status = -ENOMEM;
153                 page = grab_cache_page(mapping, index);
154                 if (!page)
155                         break;
156
157                 status = mapping->a_ops->prepare_write(NULL, page, offset,
158                                                         offset + bytes);
159                 if (status)
160                         goto unlock;
161
162                 zero_user_page(page, offset, bytes, KM_USER0);
163
164                 status = mapping->a_ops->commit_write(NULL, page, offset,
165                                                         offset + bytes);
166                 if (!status) {
167                         pos += bytes;
168                         count -= bytes;
169                 }
170
171 unlock:
172                 unlock_page(page);
173                 page_cache_release(page);
174                 if (status)
175                         break;
176         } while (count);
177
178         return (-status);
179 }
180
181 ssize_t                 /* bytes read, or (-)  error */
182 xfs_read(
183         bhv_desc_t              *bdp,
184         struct kiocb            *iocb,
185         const struct iovec      *iovp,
186         unsigned int            segs,
187         loff_t                  *offset,
188         int                     ioflags,
189         cred_t                  *credp)
190 {
191         struct file             *file = iocb->ki_filp;
192         struct inode            *inode = file->f_mapping->host;
193         size_t                  size = 0;
194         ssize_t                 ret = 0;
195         xfs_fsize_t             n;
196         xfs_inode_t             *ip;
197         xfs_mount_t             *mp;
198         bhv_vnode_t             *vp;
199         unsigned long           seg;
200
201         ip = XFS_BHVTOI(bdp);
202         vp = BHV_TO_VNODE(bdp);
203         mp = ip->i_mount;
204
205         XFS_STATS_INC(xs_read_calls);
206
207         /* START copy & waste from filemap.c */
208         for (seg = 0; seg < segs; seg++) {
209                 const struct iovec *iv = &iovp[seg];
210
211                 /*
212                  * If any segment has a negative length, or the cumulative
213                  * length ever wraps negative then return -EINVAL.
214                  */
215                 size += iv->iov_len;
216                 if (unlikely((ssize_t)(size|iv->iov_len) < 0))
217                         return XFS_ERROR(-EINVAL);
218         }
219         /* END copy & waste from filemap.c */
220
221         if (unlikely(ioflags & IO_ISDIRECT)) {
222                 xfs_buftarg_t   *target =
223                         (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
224                                 mp->m_rtdev_targp : mp->m_ddev_targp;
225                 if ((*offset & target->bt_smask) ||
226                     (size & target->bt_smask)) {
227                         if (*offset == ip->i_size) {
228                                 return (0);
229                         }
230                         return -XFS_ERROR(EINVAL);
231                 }
232         }
233
234         n = XFS_MAXIOFFSET(mp) - *offset;
235         if ((n <= 0) || (size == 0))
236                 return 0;
237
238         if (n < size)
239                 size = n;
240
241         if (XFS_FORCED_SHUTDOWN(mp))
242                 return -EIO;
243
244         if (unlikely(ioflags & IO_ISDIRECT))
245                 mutex_lock(&inode->i_mutex);
246         xfs_ilock(ip, XFS_IOLOCK_SHARED);
247
248         if (DM_EVENT_ENABLED(vp->v_vfsp, ip, DM_EVENT_READ) &&
249             !(ioflags & IO_INVIS)) {
250                 bhv_vrwlock_t locktype = VRWLOCK_READ;
251                 int dmflags = FILP_DELAY_FLAG(file) | DM_SEM_FLAG_RD(ioflags);
252
253                 ret = -XFS_SEND_DATA(mp, DM_EVENT_READ,
254                                         BHV_TO_VNODE(bdp), *offset, size,
255                                         dmflags, &locktype);
256                 if (ret) {
257                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
258                         if (unlikely(ioflags & IO_ISDIRECT))
259                                 mutex_unlock(&inode->i_mutex);
260                         return ret;
261                 }
262         }
263
264         if (unlikely(ioflags & IO_ISDIRECT)) {
265                 if (VN_CACHED(vp))
266                         ret = bhv_vop_flushinval_pages(vp, ctooff(offtoct(*offset)),
267                                                  -1, FI_REMAPF_LOCKED);
268                 mutex_unlock(&inode->i_mutex);
269                 if (ret) {
270                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
271                         return ret;
272                 }
273         }
274
275         xfs_rw_enter_trace(XFS_READ_ENTER, &ip->i_iocore,
276                                 (void *)iovp, segs, *offset, ioflags);
277
278         iocb->ki_pos = *offset;
279         ret = generic_file_aio_read(iocb, iovp, segs, *offset);
280         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
281                 ret = wait_on_sync_kiocb(iocb);
282         if (ret > 0)
283                 XFS_STATS_ADD(xs_read_bytes, ret);
284
285         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
286         return ret;
287 }
288
289 ssize_t
290 xfs_sendfile(
291         bhv_desc_t              *bdp,
292         struct file             *filp,
293         loff_t                  *offset,
294         int                     ioflags,
295         size_t                  count,
296         read_actor_t            actor,
297         void                    *target,
298         cred_t                  *credp)
299 {
300         xfs_inode_t             *ip = XFS_BHVTOI(bdp);
301         xfs_mount_t             *mp = ip->i_mount;
302         ssize_t                 ret;
303
304         XFS_STATS_INC(xs_read_calls);
305         if (XFS_FORCED_SHUTDOWN(mp))
306                 return -EIO;
307
308         xfs_ilock(ip, XFS_IOLOCK_SHARED);
309
310         if (DM_EVENT_ENABLED(BHV_TO_VNODE(bdp)->v_vfsp, ip, DM_EVENT_READ) &&
311             (!(ioflags & IO_INVIS))) {
312                 bhv_vrwlock_t locktype = VRWLOCK_READ;
313                 int error;
314
315                 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp),
316                                       *offset, count,
317                                       FILP_DELAY_FLAG(filp), &locktype);
318                 if (error) {
319                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
320                         return -error;
321                 }
322         }
323         xfs_rw_enter_trace(XFS_SENDFILE_ENTER, &ip->i_iocore,
324                    (void *)(unsigned long)target, count, *offset, ioflags);
325         ret = generic_file_sendfile(filp, offset, count, actor, target);
326         if (ret > 0)
327                 XFS_STATS_ADD(xs_read_bytes, ret);
328
329         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
330         return ret;
331 }
332
333 ssize_t
334 xfs_splice_read(
335         bhv_desc_t              *bdp,
336         struct file             *infilp,
337         loff_t                  *ppos,
338         struct pipe_inode_info  *pipe,
339         size_t                  count,
340         int                     flags,
341         int                     ioflags,
342         cred_t                  *credp)
343 {
344         xfs_inode_t             *ip = XFS_BHVTOI(bdp);
345         xfs_mount_t             *mp = ip->i_mount;
346         ssize_t                 ret;
347
348         XFS_STATS_INC(xs_read_calls);
349         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
350                 return -EIO;
351
352         xfs_ilock(ip, XFS_IOLOCK_SHARED);
353
354         if (DM_EVENT_ENABLED(BHV_TO_VNODE(bdp)->v_vfsp, ip, DM_EVENT_READ) &&
355             (!(ioflags & IO_INVIS))) {
356                 bhv_vrwlock_t locktype = VRWLOCK_READ;
357                 int error;
358
359                 error = XFS_SEND_DATA(mp, DM_EVENT_READ, BHV_TO_VNODE(bdp),
360                                         *ppos, count,
361                                         FILP_DELAY_FLAG(infilp), &locktype);
362                 if (error) {
363                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
364                         return -error;
365                 }
366         }
367         xfs_rw_enter_trace(XFS_SPLICE_READ_ENTER, &ip->i_iocore,
368                            pipe, count, *ppos, ioflags);
369         ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
370         if (ret > 0)
371                 XFS_STATS_ADD(xs_read_bytes, ret);
372
373         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
374         return ret;
375 }
376
377 ssize_t
378 xfs_splice_write(
379         bhv_desc_t              *bdp,
380         struct pipe_inode_info  *pipe,
381         struct file             *outfilp,
382         loff_t                  *ppos,
383         size_t                  count,
384         int                     flags,
385         int                     ioflags,
386         cred_t                  *credp)
387 {
388         xfs_inode_t             *ip = XFS_BHVTOI(bdp);
389         xfs_mount_t             *mp = ip->i_mount;
390         xfs_iocore_t            *io = &ip->i_iocore;
391         ssize_t                 ret;
392         struct inode            *inode = outfilp->f_mapping->host;
393         xfs_fsize_t             isize, new_size;
394
395         XFS_STATS_INC(xs_write_calls);
396         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
397                 return -EIO;
398
399         xfs_ilock(ip, XFS_IOLOCK_EXCL);
400
401         if (DM_EVENT_ENABLED(BHV_TO_VNODE(bdp)->v_vfsp, ip, DM_EVENT_WRITE) &&
402             (!(ioflags & IO_INVIS))) {
403                 bhv_vrwlock_t locktype = VRWLOCK_WRITE;
404                 int error;
405
406                 error = XFS_SEND_DATA(mp, DM_EVENT_WRITE, BHV_TO_VNODE(bdp),
407                                         *ppos, count,
408                                         FILP_DELAY_FLAG(outfilp), &locktype);
409                 if (error) {
410                         xfs_iunlock(ip, XFS_IOLOCK_EXCL);
411                         return -error;
412                 }
413         }
414
415         new_size = *ppos + count;
416
417         xfs_ilock(ip, XFS_ILOCK_EXCL);
418         if (new_size > ip->i_size)
419                 io->io_new_size = new_size;
420         xfs_iunlock(ip, XFS_ILOCK_EXCL);
421
422         xfs_rw_enter_trace(XFS_SPLICE_WRITE_ENTER, &ip->i_iocore,
423                            pipe, count, *ppos, ioflags);
424         ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
425         if (ret > 0)
426                 XFS_STATS_ADD(xs_write_bytes, ret);
427
428         isize = i_size_read(inode);
429         if (unlikely(ret < 0 && ret != -EFAULT && *ppos > isize))
430                 *ppos = isize;
431
432         if (*ppos > ip->i_size) {
433                 xfs_ilock(ip, XFS_ILOCK_EXCL);
434                 if (*ppos > ip->i_size)
435                         ip->i_size = *ppos;
436                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
437         }
438
439         if (io->io_new_size) {
440                 xfs_ilock(ip, XFS_ILOCK_EXCL);
441                 io->io_new_size = 0;
442                 if (ip->i_d.di_size > ip->i_size)
443                         ip->i_d.di_size = ip->i_size;
444                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
445         }
446         xfs_iunlock(ip, XFS_IOLOCK_EXCL);
447         return ret;
448 }
449
450 /*
451  * This routine is called to handle zeroing any space in the last
452  * block of the file that is beyond the EOF.  We do this since the
453  * size is being increased without writing anything to that block
454  * and we don't want anyone to read the garbage on the disk.
455  */
456 STATIC int                              /* error (positive) */
457 xfs_zero_last_block(
458         struct inode    *ip,
459         xfs_iocore_t    *io,
460         xfs_fsize_t     offset,
461         xfs_fsize_t     isize)
462 {
463         xfs_fileoff_t   last_fsb;
464         xfs_mount_t     *mp = io->io_mount;
465         int             nimaps;
466         int             zero_offset;
467         int             zero_len;
468         int             error = 0;
469         xfs_bmbt_irec_t imap;
470
471         ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
472
473         zero_offset = XFS_B_FSB_OFFSET(mp, isize);
474         if (zero_offset == 0) {
475                 /*
476                  * There are no extra bytes in the last block on disk to
477                  * zero, so return.
478                  */
479                 return 0;
480         }
481
482         last_fsb = XFS_B_TO_FSBT(mp, isize);
483         nimaps = 1;
484         error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
485                           &nimaps, NULL, NULL);
486         if (error) {
487                 return error;
488         }
489         ASSERT(nimaps > 0);
490         /*
491          * If the block underlying isize is just a hole, then there
492          * is nothing to zero.
493          */
494         if (imap.br_startblock == HOLESTARTBLOCK) {
495                 return 0;
496         }
497         /*
498          * Zero the part of the last block beyond the EOF, and write it
499          * out sync.  We need to drop the ilock while we do this so we
500          * don't deadlock when the buffer cache calls back to us.
501          */
502         XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
503
504         zero_len = mp->m_sb.sb_blocksize - zero_offset;
505         if (isize + zero_len > offset)
506                 zero_len = offset - isize;
507         error = xfs_iozero(ip, isize, zero_len);
508
509         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
510         ASSERT(error >= 0);
511         return error;
512 }
513
514 /*
515  * Zero any on disk space between the current EOF and the new,
516  * larger EOF.  This handles the normal case of zeroing the remainder
517  * of the last block in the file and the unusual case of zeroing blocks
518  * out beyond the size of the file.  This second case only happens
519  * with fixed size extents and when the system crashes before the inode
520  * size was updated but after blocks were allocated.  If fill is set,
521  * then any holes in the range are filled and zeroed.  If not, the holes
522  * are left alone as holes.
523  */
524
525 int                                     /* error (positive) */
526 xfs_zero_eof(
527         bhv_vnode_t     *vp,
528         xfs_iocore_t    *io,
529         xfs_off_t       offset,         /* starting I/O offset */
530         xfs_fsize_t     isize)          /* current inode size */
531 {
532         struct inode    *ip = vn_to_inode(vp);
533         xfs_fileoff_t   start_zero_fsb;
534         xfs_fileoff_t   end_zero_fsb;
535         xfs_fileoff_t   zero_count_fsb;
536         xfs_fileoff_t   last_fsb;
537         xfs_fileoff_t   zero_off;
538         xfs_fsize_t     zero_len;
539         xfs_mount_t     *mp = io->io_mount;
540         int             nimaps;
541         int             error = 0;
542         xfs_bmbt_irec_t imap;
543
544         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
545         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
546         ASSERT(offset > isize);
547
548         /*
549          * First handle zeroing the block on which isize resides.
550          * We only zero a part of that block so it is handled specially.
551          */
552         error = xfs_zero_last_block(ip, io, offset, isize);
553         if (error) {
554                 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
555                 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
556                 return error;
557         }
558
559         /*
560          * Calculate the range between the new size and the old
561          * where blocks needing to be zeroed may exist.  To get the
562          * block where the last byte in the file currently resides,
563          * we need to subtract one from the size and truncate back
564          * to a block boundary.  We subtract 1 in case the size is
565          * exactly on a block boundary.
566          */
567         last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
568         start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
569         end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
570         ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
571         if (last_fsb == end_zero_fsb) {
572                 /*
573                  * The size was only incremented on its last block.
574                  * We took care of that above, so just return.
575                  */
576                 return 0;
577         }
578
579         ASSERT(start_zero_fsb <= end_zero_fsb);
580         while (start_zero_fsb <= end_zero_fsb) {
581                 nimaps = 1;
582                 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
583                 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
584                                   0, NULL, 0, &imap, &nimaps, NULL, NULL);
585                 if (error) {
586                         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
587                         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
588                         return error;
589                 }
590                 ASSERT(nimaps > 0);
591
592                 if (imap.br_state == XFS_EXT_UNWRITTEN ||
593                     imap.br_startblock == HOLESTARTBLOCK) {
594                         /*
595                          * This loop handles initializing pages that were
596                          * partially initialized by the code below this
597                          * loop. It basically zeroes the part of the page
598                          * that sits on a hole and sets the page as P_HOLE
599                          * and calls remapf if it is a mapped file.
600                          */
601                         start_zero_fsb = imap.br_startoff + imap.br_blockcount;
602                         ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
603                         continue;
604                 }
605
606                 /*
607                  * There are blocks we need to zero.
608                  * Drop the inode lock while we're doing the I/O.
609                  * We'll still have the iolock to protect us.
610                  */
611                 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
612
613                 zero_off = XFS_FSB_TO_B(mp, start_zero_fsb);
614                 zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount);
615
616                 if ((zero_off + zero_len) > offset)
617                         zero_len = offset - zero_off;
618
619                 error = xfs_iozero(ip, zero_off, zero_len);
620                 if (error) {
621                         goto out_lock;
622                 }
623
624                 start_zero_fsb = imap.br_startoff + imap.br_blockcount;
625                 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
626
627                 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
628         }
629
630         return 0;
631
632 out_lock:
633
634         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
635         ASSERT(error >= 0);
636         return error;
637 }
638
639 ssize_t                         /* bytes written, or (-) error */
640 xfs_write(
641         bhv_desc_t              *bdp,
642         struct kiocb            *iocb,
643         const struct iovec      *iovp,
644         unsigned int            nsegs,
645         loff_t                  *offset,
646         int                     ioflags,
647         cred_t                  *credp)
648 {
649         struct file             *file = iocb->ki_filp;
650         struct address_space    *mapping = file->f_mapping;
651         struct inode            *inode = mapping->host;
652         unsigned long           segs = nsegs;
653         xfs_inode_t             *xip;
654         xfs_mount_t             *mp;
655         ssize_t                 ret = 0, error = 0;
656         xfs_fsize_t             isize, new_size;
657         xfs_iocore_t            *io;
658         bhv_vnode_t             *vp;
659         int                     iolock;
660         int                     eventsent = 0;
661         bhv_vrwlock_t           locktype;
662         size_t                  ocount = 0, count;
663         loff_t                  pos;
664         int                     need_i_mutex;
665
666         XFS_STATS_INC(xs_write_calls);
667
668         vp = BHV_TO_VNODE(bdp);
669         xip = XFS_BHVTOI(bdp);
670
671         error = generic_segment_checks(iovp, &segs, &ocount, VERIFY_READ);
672         if (error)
673                 return error;
674
675         count = ocount;
676         pos = *offset;
677
678         if (count == 0)
679                 return 0;
680
681         io = &xip->i_iocore;
682         mp = io->io_mount;
683
684         vfs_wait_for_freeze(vp->v_vfsp, SB_FREEZE_WRITE);
685
686         if (XFS_FORCED_SHUTDOWN(mp))
687                 return -EIO;
688
689 relock:
690         if (ioflags & IO_ISDIRECT) {
691                 iolock = XFS_IOLOCK_SHARED;
692                 locktype = VRWLOCK_WRITE_DIRECT;
693                 need_i_mutex = 0;
694         } else {
695                 iolock = XFS_IOLOCK_EXCL;
696                 locktype = VRWLOCK_WRITE;
697                 need_i_mutex = 1;
698                 mutex_lock(&inode->i_mutex);
699         }
700
701         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
702
703 start:
704         error = -generic_write_checks(file, &pos, &count,
705                                         S_ISBLK(inode->i_mode));
706         if (error) {
707                 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
708                 goto out_unlock_mutex;
709         }
710
711         if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
712             !(ioflags & IO_INVIS) && !eventsent)) {
713                 int             dmflags = FILP_DELAY_FLAG(file);
714
715                 if (need_i_mutex)
716                         dmflags |= DM_FLAGS_IMUX;
717
718                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
719                 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
720                                       pos, count,
721                                       dmflags, &locktype);
722                 if (error) {
723                         goto out_unlock_internal;
724                 }
725                 xfs_ilock(xip, XFS_ILOCK_EXCL);
726                 eventsent = 1;
727
728                 /*
729                  * The iolock was dropped and reacquired in XFS_SEND_DATA
730                  * so we have to recheck the size when appending.
731                  * We will only "goto start;" once, since having sent the
732                  * event prevents another call to XFS_SEND_DATA, which is
733                  * what allows the size to change in the first place.
734                  */
735                 if ((file->f_flags & O_APPEND) && pos != xip->i_size)
736                         goto start;
737         }
738
739         if (ioflags & IO_ISDIRECT) {
740                 xfs_buftarg_t   *target =
741                         (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
742                                 mp->m_rtdev_targp : mp->m_ddev_targp;
743
744                 if ((pos & target->bt_smask) || (count & target->bt_smask)) {
745                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
746                         return XFS_ERROR(-EINVAL);
747                 }
748
749                 if (!need_i_mutex && (VN_CACHED(vp) || pos > xip->i_size)) {
750                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
751                         iolock = XFS_IOLOCK_EXCL;
752                         locktype = VRWLOCK_WRITE;
753                         need_i_mutex = 1;
754                         mutex_lock(&inode->i_mutex);
755                         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
756                         goto start;
757                 }
758         }
759
760         new_size = pos + count;
761         if (new_size > xip->i_size)
762                 io->io_new_size = new_size;
763
764         if (likely(!(ioflags & IO_INVIS))) {
765                 file_update_time(file);
766                 xfs_ichgtime_fast(xip, inode,
767                                   XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
768         }
769
770         /*
771          * If the offset is beyond the size of the file, we have a couple
772          * of things to do. First, if there is already space allocated
773          * we need to either create holes or zero the disk or ...
774          *
775          * If there is a page where the previous size lands, we need
776          * to zero it out up to the new size.
777          */
778
779         if (pos > xip->i_size) {
780                 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos, xip->i_size);
781                 if (error) {
782                         xfs_iunlock(xip, XFS_ILOCK_EXCL);
783                         goto out_unlock_internal;
784                 }
785         }
786         xfs_iunlock(xip, XFS_ILOCK_EXCL);
787
788         /*
789          * If we're writing the file then make sure to clear the
790          * setuid and setgid bits if the process is not being run
791          * by root.  This keeps people from modifying setuid and
792          * setgid binaries.
793          */
794
795         if (((xip->i_d.di_mode & S_ISUID) ||
796             ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
797                 (S_ISGID | S_IXGRP))) &&
798              !capable(CAP_FSETID)) {
799                 error = xfs_write_clear_setuid(xip);
800                 if (likely(!error))
801                         error = -remove_suid(file->f_path.dentry);
802                 if (unlikely(error)) {
803                         goto out_unlock_internal;
804                 }
805         }
806
807 retry:
808         /* We can write back this queue in page reclaim */
809         current->backing_dev_info = mapping->backing_dev_info;
810
811         if ((ioflags & IO_ISDIRECT)) {
812                 if (VN_CACHED(vp)) {
813                         WARN_ON(need_i_mutex == 0);
814                         xfs_inval_cached_trace(io, pos, -1,
815                                         ctooff(offtoct(pos)), -1);
816                         error = bhv_vop_flushinval_pages(vp, ctooff(offtoct(pos)),
817                                         -1, FI_REMAPF_LOCKED);
818                         if (error)
819                                 goto out_unlock_internal;
820                 }
821
822                 if (need_i_mutex) {
823                         /* demote the lock now the cached pages are gone */
824                         XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
825                         mutex_unlock(&inode->i_mutex);
826
827                         iolock = XFS_IOLOCK_SHARED;
828                         locktype = VRWLOCK_WRITE_DIRECT;
829                         need_i_mutex = 0;
830                 }
831
832                 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
833                                 *offset, ioflags);
834                 ret = generic_file_direct_write(iocb, iovp,
835                                 &segs, pos, offset, count, ocount);
836
837                 /*
838                  * direct-io write to a hole: fall through to buffered I/O
839                  * for completing the rest of the request.
840                  */
841                 if (ret >= 0 && ret != count) {
842                         XFS_STATS_ADD(xs_write_bytes, ret);
843
844                         pos += ret;
845                         count -= ret;
846
847                         ioflags &= ~IO_ISDIRECT;
848                         xfs_iunlock(xip, iolock);
849                         goto relock;
850                 }
851         } else {
852                 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
853                                 *offset, ioflags);
854                 ret = generic_file_buffered_write(iocb, iovp, segs,
855                                 pos, offset, count, ret);
856         }
857
858         current->backing_dev_info = NULL;
859
860         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
861                 ret = wait_on_sync_kiocb(iocb);
862
863         if ((ret == -ENOSPC) &&
864             DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
865             !(ioflags & IO_INVIS)) {
866
867                 xfs_rwunlock(bdp, locktype);
868                 if (need_i_mutex)
869                         mutex_unlock(&inode->i_mutex);
870                 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
871                                 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
872                                 0, 0, 0); /* Delay flag intentionally  unused */
873                 if (need_i_mutex)
874                         mutex_lock(&inode->i_mutex);
875                 xfs_rwlock(bdp, locktype);
876                 if (error)
877                         goto out_unlock_internal;
878                 pos = xip->i_size;
879                 ret = 0;
880                 goto retry;
881         }
882
883         isize = i_size_read(inode);
884         if (unlikely(ret < 0 && ret != -EFAULT && *offset > isize))
885                 *offset = isize;
886
887         if (*offset > xip->i_size) {
888                 xfs_ilock(xip, XFS_ILOCK_EXCL);
889                 if (*offset > xip->i_size)
890                         xip->i_size = *offset;
891                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
892         }
893
894         error = -ret;
895         if (ret <= 0)
896                 goto out_unlock_internal;
897
898         XFS_STATS_ADD(xs_write_bytes, ret);
899
900         /* Handle various SYNC-type writes */
901         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
902                 error = xfs_write_sync_logforce(mp, xip);
903                 if (error)
904                         goto out_unlock_internal;
905
906                 xfs_rwunlock(bdp, locktype);
907                 if (need_i_mutex)
908                         mutex_unlock(&inode->i_mutex);
909
910                 error = sync_page_range(inode, mapping, pos, ret);
911                 if (!error)
912                         error = -ret;
913                 if (need_i_mutex)
914                         mutex_lock(&inode->i_mutex);
915                 xfs_rwlock(bdp, locktype);
916         }
917
918  out_unlock_internal:
919         if (io->io_new_size) {
920                 xfs_ilock(xip, XFS_ILOCK_EXCL);
921                 io->io_new_size = 0;
922                 /*
923                  * If this was a direct or synchronous I/O that failed (such
924                  * as ENOSPC) then part of the I/O may have been written to
925                  * disk before the error occured.  In this case the on-disk
926                  * file size may have been adjusted beyond the in-memory file
927                  * size and now needs to be truncated back.
928                  */
929                 if (xip->i_d.di_size > xip->i_size)
930                         xip->i_d.di_size = xip->i_size;
931                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
932         }
933         xfs_rwunlock(bdp, locktype);
934  out_unlock_mutex:
935         if (need_i_mutex)
936                 mutex_unlock(&inode->i_mutex);
937         return -error;
938 }
939
940 /*
941  * All xfs metadata buffers except log state machine buffers
942  * get this attached as their b_bdstrat callback function.
943  * This is so that we can catch a buffer
944  * after prematurely unpinning it to forcibly shutdown the filesystem.
945  */
946 int
947 xfs_bdstrat_cb(struct xfs_buf *bp)
948 {
949         xfs_mount_t     *mp;
950
951         mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
952         if (!XFS_FORCED_SHUTDOWN(mp)) {
953                 xfs_buf_iorequest(bp);
954                 return 0;
955         } else {
956                 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
957                 /*
958                  * Metadata write that didn't get logged but
959                  * written delayed anyway. These aren't associated
960                  * with a transaction, and can be ignored.
961                  */
962                 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
963                     (XFS_BUF_ISREAD(bp)) == 0)
964                         return (xfs_bioerror_relse(bp));
965                 else
966                         return (xfs_bioerror(bp));
967         }
968 }
969
970
971 int
972 xfs_bmap(bhv_desc_t     *bdp,
973         xfs_off_t       offset,
974         ssize_t         count,
975         int             flags,
976         xfs_iomap_t     *iomapp,
977         int             *niomaps)
978 {
979         xfs_inode_t     *ip = XFS_BHVTOI(bdp);
980         xfs_iocore_t    *io = &ip->i_iocore;
981
982         ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
983         ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
984                ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
985
986         return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
987 }
988
989 /*
990  * Wrapper around bdstrat so that we can stop data
991  * from going to disk in case we are shutting down the filesystem.
992  * Typically user data goes thru this path; one of the exceptions
993  * is the superblock.
994  */
995 int
996 xfsbdstrat(
997         struct xfs_mount        *mp,
998         struct xfs_buf          *bp)
999 {
1000         ASSERT(mp);
1001         if (!XFS_FORCED_SHUTDOWN(mp)) {
1002                 /* Grio redirection would go here
1003                  * if (XFS_BUF_IS_GRIO(bp)) {
1004                  */
1005
1006                 xfs_buf_iorequest(bp);
1007                 return 0;
1008         }
1009
1010         xfs_buftrace("XFSBDSTRAT IOERROR", bp);
1011         return (xfs_bioerror_relse(bp));
1012 }
1013
1014 /*
1015  * If the underlying (data/log/rt) device is readonly, there are some
1016  * operations that cannot proceed.
1017  */
1018 int
1019 xfs_dev_is_read_only(
1020         xfs_mount_t             *mp,
1021         char                    *message)
1022 {
1023         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
1024             xfs_readonly_buftarg(mp->m_logdev_targp) ||
1025             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
1026                 cmn_err(CE_NOTE,
1027                         "XFS: %s required on read-only device.", message);
1028                 cmn_err(CE_NOTE,
1029                         "XFS: write access unavailable, cannot proceed.");
1030                 return EROFS;
1031         }
1032         return 0;
1033 }