Merge master.kernel.org:/pub/scm/linux/kernel/git/davej/agpgart
[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_splice_read(
291         bhv_desc_t              *bdp,
292         struct file             *infilp,
293         loff_t                  *ppos,
294         struct pipe_inode_info  *pipe,
295         size_t                  count,
296         int                     flags,
297         int                     ioflags,
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(ip->i_mount))
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                                         *ppos, count,
317                                         FILP_DELAY_FLAG(infilp), &locktype);
318                 if (error) {
319                         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
320                         return -error;
321                 }
322         }
323         xfs_rw_enter_trace(XFS_SPLICE_READ_ENTER, &ip->i_iocore,
324                            pipe, count, *ppos, ioflags);
325         ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
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_write(
335         bhv_desc_t              *bdp,
336         struct pipe_inode_info  *pipe,
337         struct file             *outfilp,
338         loff_t                  *ppos,
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         xfs_iocore_t            *io = &ip->i_iocore;
347         ssize_t                 ret;
348         struct inode            *inode = outfilp->f_mapping->host;
349         xfs_fsize_t             isize, new_size;
350
351         XFS_STATS_INC(xs_write_calls);
352         if (XFS_FORCED_SHUTDOWN(ip->i_mount))
353                 return -EIO;
354
355         xfs_ilock(ip, XFS_IOLOCK_EXCL);
356
357         if (DM_EVENT_ENABLED(BHV_TO_VNODE(bdp)->v_vfsp, ip, DM_EVENT_WRITE) &&
358             (!(ioflags & IO_INVIS))) {
359                 bhv_vrwlock_t locktype = VRWLOCK_WRITE;
360                 int error;
361
362                 error = XFS_SEND_DATA(mp, DM_EVENT_WRITE, BHV_TO_VNODE(bdp),
363                                         *ppos, count,
364                                         FILP_DELAY_FLAG(outfilp), &locktype);
365                 if (error) {
366                         xfs_iunlock(ip, XFS_IOLOCK_EXCL);
367                         return -error;
368                 }
369         }
370
371         new_size = *ppos + count;
372
373         xfs_ilock(ip, XFS_ILOCK_EXCL);
374         if (new_size > ip->i_size)
375                 io->io_new_size = new_size;
376         xfs_iunlock(ip, XFS_ILOCK_EXCL);
377
378         xfs_rw_enter_trace(XFS_SPLICE_WRITE_ENTER, &ip->i_iocore,
379                            pipe, count, *ppos, ioflags);
380         ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
381         if (ret > 0)
382                 XFS_STATS_ADD(xs_write_bytes, ret);
383
384         isize = i_size_read(inode);
385         if (unlikely(ret < 0 && ret != -EFAULT && *ppos > isize))
386                 *ppos = isize;
387
388         if (*ppos > ip->i_size) {
389                 xfs_ilock(ip, XFS_ILOCK_EXCL);
390                 if (*ppos > ip->i_size)
391                         ip->i_size = *ppos;
392                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
393         }
394
395         if (io->io_new_size) {
396                 xfs_ilock(ip, XFS_ILOCK_EXCL);
397                 io->io_new_size = 0;
398                 if (ip->i_d.di_size > ip->i_size)
399                         ip->i_d.di_size = ip->i_size;
400                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
401         }
402         xfs_iunlock(ip, XFS_IOLOCK_EXCL);
403         return ret;
404 }
405
406 /*
407  * This routine is called to handle zeroing any space in the last
408  * block of the file that is beyond the EOF.  We do this since the
409  * size is being increased without writing anything to that block
410  * and we don't want anyone to read the garbage on the disk.
411  */
412 STATIC int                              /* error (positive) */
413 xfs_zero_last_block(
414         struct inode    *ip,
415         xfs_iocore_t    *io,
416         xfs_fsize_t     offset,
417         xfs_fsize_t     isize)
418 {
419         xfs_fileoff_t   last_fsb;
420         xfs_mount_t     *mp = io->io_mount;
421         int             nimaps;
422         int             zero_offset;
423         int             zero_len;
424         int             error = 0;
425         xfs_bmbt_irec_t imap;
426
427         ASSERT(ismrlocked(io->io_lock, MR_UPDATE) != 0);
428
429         zero_offset = XFS_B_FSB_OFFSET(mp, isize);
430         if (zero_offset == 0) {
431                 /*
432                  * There are no extra bytes in the last block on disk to
433                  * zero, so return.
434                  */
435                 return 0;
436         }
437
438         last_fsb = XFS_B_TO_FSBT(mp, isize);
439         nimaps = 1;
440         error = XFS_BMAPI(mp, NULL, io, last_fsb, 1, 0, NULL, 0, &imap,
441                           &nimaps, NULL, NULL);
442         if (error) {
443                 return error;
444         }
445         ASSERT(nimaps > 0);
446         /*
447          * If the block underlying isize is just a hole, then there
448          * is nothing to zero.
449          */
450         if (imap.br_startblock == HOLESTARTBLOCK) {
451                 return 0;
452         }
453         /*
454          * Zero the part of the last block beyond the EOF, and write it
455          * out sync.  We need to drop the ilock while we do this so we
456          * don't deadlock when the buffer cache calls back to us.
457          */
458         XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL| XFS_EXTSIZE_RD);
459
460         zero_len = mp->m_sb.sb_blocksize - zero_offset;
461         if (isize + zero_len > offset)
462                 zero_len = offset - isize;
463         error = xfs_iozero(ip, isize, zero_len);
464
465         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
466         ASSERT(error >= 0);
467         return error;
468 }
469
470 /*
471  * Zero any on disk space between the current EOF and the new,
472  * larger EOF.  This handles the normal case of zeroing the remainder
473  * of the last block in the file and the unusual case of zeroing blocks
474  * out beyond the size of the file.  This second case only happens
475  * with fixed size extents and when the system crashes before the inode
476  * size was updated but after blocks were allocated.  If fill is set,
477  * then any holes in the range are filled and zeroed.  If not, the holes
478  * are left alone as holes.
479  */
480
481 int                                     /* error (positive) */
482 xfs_zero_eof(
483         bhv_vnode_t     *vp,
484         xfs_iocore_t    *io,
485         xfs_off_t       offset,         /* starting I/O offset */
486         xfs_fsize_t     isize)          /* current inode size */
487 {
488         struct inode    *ip = vn_to_inode(vp);
489         xfs_fileoff_t   start_zero_fsb;
490         xfs_fileoff_t   end_zero_fsb;
491         xfs_fileoff_t   zero_count_fsb;
492         xfs_fileoff_t   last_fsb;
493         xfs_fileoff_t   zero_off;
494         xfs_fsize_t     zero_len;
495         xfs_mount_t     *mp = io->io_mount;
496         int             nimaps;
497         int             error = 0;
498         xfs_bmbt_irec_t imap;
499
500         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
501         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
502         ASSERT(offset > isize);
503
504         /*
505          * First handle zeroing the block on which isize resides.
506          * We only zero a part of that block so it is handled specially.
507          */
508         error = xfs_zero_last_block(ip, io, offset, isize);
509         if (error) {
510                 ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
511                 ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
512                 return error;
513         }
514
515         /*
516          * Calculate the range between the new size and the old
517          * where blocks needing to be zeroed may exist.  To get the
518          * block where the last byte in the file currently resides,
519          * we need to subtract one from the size and truncate back
520          * to a block boundary.  We subtract 1 in case the size is
521          * exactly on a block boundary.
522          */
523         last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1;
524         start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize);
525         end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1);
526         ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb);
527         if (last_fsb == end_zero_fsb) {
528                 /*
529                  * The size was only incremented on its last block.
530                  * We took care of that above, so just return.
531                  */
532                 return 0;
533         }
534
535         ASSERT(start_zero_fsb <= end_zero_fsb);
536         while (start_zero_fsb <= end_zero_fsb) {
537                 nimaps = 1;
538                 zero_count_fsb = end_zero_fsb - start_zero_fsb + 1;
539                 error = XFS_BMAPI(mp, NULL, io, start_zero_fsb, zero_count_fsb,
540                                   0, NULL, 0, &imap, &nimaps, NULL, NULL);
541                 if (error) {
542                         ASSERT(ismrlocked(io->io_lock, MR_UPDATE));
543                         ASSERT(ismrlocked(io->io_iolock, MR_UPDATE));
544                         return error;
545                 }
546                 ASSERT(nimaps > 0);
547
548                 if (imap.br_state == XFS_EXT_UNWRITTEN ||
549                     imap.br_startblock == HOLESTARTBLOCK) {
550                         /*
551                          * This loop handles initializing pages that were
552                          * partially initialized by the code below this
553                          * loop. It basically zeroes the part of the page
554                          * that sits on a hole and sets the page as P_HOLE
555                          * and calls remapf if it is a mapped file.
556                          */
557                         start_zero_fsb = imap.br_startoff + imap.br_blockcount;
558                         ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
559                         continue;
560                 }
561
562                 /*
563                  * There are blocks we need to zero.
564                  * Drop the inode lock while we're doing the I/O.
565                  * We'll still have the iolock to protect us.
566                  */
567                 XFS_IUNLOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
568
569                 zero_off = XFS_FSB_TO_B(mp, start_zero_fsb);
570                 zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount);
571
572                 if ((zero_off + zero_len) > offset)
573                         zero_len = offset - zero_off;
574
575                 error = xfs_iozero(ip, zero_off, zero_len);
576                 if (error) {
577                         goto out_lock;
578                 }
579
580                 start_zero_fsb = imap.br_startoff + imap.br_blockcount;
581                 ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
582
583                 XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
584         }
585
586         return 0;
587
588 out_lock:
589
590         XFS_ILOCK(mp, io, XFS_ILOCK_EXCL|XFS_EXTSIZE_RD);
591         ASSERT(error >= 0);
592         return error;
593 }
594
595 ssize_t                         /* bytes written, or (-) error */
596 xfs_write(
597         bhv_desc_t              *bdp,
598         struct kiocb            *iocb,
599         const struct iovec      *iovp,
600         unsigned int            nsegs,
601         loff_t                  *offset,
602         int                     ioflags,
603         cred_t                  *credp)
604 {
605         struct file             *file = iocb->ki_filp;
606         struct address_space    *mapping = file->f_mapping;
607         struct inode            *inode = mapping->host;
608         unsigned long           segs = nsegs;
609         xfs_inode_t             *xip;
610         xfs_mount_t             *mp;
611         ssize_t                 ret = 0, error = 0;
612         xfs_fsize_t             isize, new_size;
613         xfs_iocore_t            *io;
614         bhv_vnode_t             *vp;
615         int                     iolock;
616         int                     eventsent = 0;
617         bhv_vrwlock_t           locktype;
618         size_t                  ocount = 0, count;
619         loff_t                  pos;
620         int                     need_i_mutex;
621
622         XFS_STATS_INC(xs_write_calls);
623
624         vp = BHV_TO_VNODE(bdp);
625         xip = XFS_BHVTOI(bdp);
626
627         error = generic_segment_checks(iovp, &segs, &ocount, VERIFY_READ);
628         if (error)
629                 return error;
630
631         count = ocount;
632         pos = *offset;
633
634         if (count == 0)
635                 return 0;
636
637         io = &xip->i_iocore;
638         mp = io->io_mount;
639
640         vfs_wait_for_freeze(vp->v_vfsp, SB_FREEZE_WRITE);
641
642         if (XFS_FORCED_SHUTDOWN(mp))
643                 return -EIO;
644
645 relock:
646         if (ioflags & IO_ISDIRECT) {
647                 iolock = XFS_IOLOCK_SHARED;
648                 locktype = VRWLOCK_WRITE_DIRECT;
649                 need_i_mutex = 0;
650         } else {
651                 iolock = XFS_IOLOCK_EXCL;
652                 locktype = VRWLOCK_WRITE;
653                 need_i_mutex = 1;
654                 mutex_lock(&inode->i_mutex);
655         }
656
657         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
658
659 start:
660         error = -generic_write_checks(file, &pos, &count,
661                                         S_ISBLK(inode->i_mode));
662         if (error) {
663                 xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
664                 goto out_unlock_mutex;
665         }
666
667         if ((DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_WRITE) &&
668             !(ioflags & IO_INVIS) && !eventsent)) {
669                 int             dmflags = FILP_DELAY_FLAG(file);
670
671                 if (need_i_mutex)
672                         dmflags |= DM_FLAGS_IMUX;
673
674                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
675                 error = XFS_SEND_DATA(xip->i_mount, DM_EVENT_WRITE, vp,
676                                       pos, count,
677                                       dmflags, &locktype);
678                 if (error) {
679                         goto out_unlock_internal;
680                 }
681                 xfs_ilock(xip, XFS_ILOCK_EXCL);
682                 eventsent = 1;
683
684                 /*
685                  * The iolock was dropped and reacquired in XFS_SEND_DATA
686                  * so we have to recheck the size when appending.
687                  * We will only "goto start;" once, since having sent the
688                  * event prevents another call to XFS_SEND_DATA, which is
689                  * what allows the size to change in the first place.
690                  */
691                 if ((file->f_flags & O_APPEND) && pos != xip->i_size)
692                         goto start;
693         }
694
695         if (ioflags & IO_ISDIRECT) {
696                 xfs_buftarg_t   *target =
697                         (xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
698                                 mp->m_rtdev_targp : mp->m_ddev_targp;
699
700                 if ((pos & target->bt_smask) || (count & target->bt_smask)) {
701                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
702                         return XFS_ERROR(-EINVAL);
703                 }
704
705                 if (!need_i_mutex && (VN_CACHED(vp) || pos > xip->i_size)) {
706                         xfs_iunlock(xip, XFS_ILOCK_EXCL|iolock);
707                         iolock = XFS_IOLOCK_EXCL;
708                         locktype = VRWLOCK_WRITE;
709                         need_i_mutex = 1;
710                         mutex_lock(&inode->i_mutex);
711                         xfs_ilock(xip, XFS_ILOCK_EXCL|iolock);
712                         goto start;
713                 }
714         }
715
716         new_size = pos + count;
717         if (new_size > xip->i_size)
718                 io->io_new_size = new_size;
719
720         if (likely(!(ioflags & IO_INVIS))) {
721                 file_update_time(file);
722                 xfs_ichgtime_fast(xip, inode,
723                                   XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
724         }
725
726         /*
727          * If the offset is beyond the size of the file, we have a couple
728          * of things to do. First, if there is already space allocated
729          * we need to either create holes or zero the disk or ...
730          *
731          * If there is a page where the previous size lands, we need
732          * to zero it out up to the new size.
733          */
734
735         if (pos > xip->i_size) {
736                 error = xfs_zero_eof(BHV_TO_VNODE(bdp), io, pos, xip->i_size);
737                 if (error) {
738                         xfs_iunlock(xip, XFS_ILOCK_EXCL);
739                         goto out_unlock_internal;
740                 }
741         }
742         xfs_iunlock(xip, XFS_ILOCK_EXCL);
743
744         /*
745          * If we're writing the file then make sure to clear the
746          * setuid and setgid bits if the process is not being run
747          * by root.  This keeps people from modifying setuid and
748          * setgid binaries.
749          */
750
751         if (((xip->i_d.di_mode & S_ISUID) ||
752             ((xip->i_d.di_mode & (S_ISGID | S_IXGRP)) ==
753                 (S_ISGID | S_IXGRP))) &&
754              !capable(CAP_FSETID)) {
755                 error = xfs_write_clear_setuid(xip);
756                 if (likely(!error))
757                         error = -remove_suid(file->f_path.dentry);
758                 if (unlikely(error)) {
759                         goto out_unlock_internal;
760                 }
761         }
762
763 retry:
764         /* We can write back this queue in page reclaim */
765         current->backing_dev_info = mapping->backing_dev_info;
766
767         if ((ioflags & IO_ISDIRECT)) {
768                 if (VN_CACHED(vp)) {
769                         WARN_ON(need_i_mutex == 0);
770                         xfs_inval_cached_trace(io, pos, -1,
771                                         ctooff(offtoct(pos)), -1);
772                         error = bhv_vop_flushinval_pages(vp, ctooff(offtoct(pos)),
773                                         -1, FI_REMAPF_LOCKED);
774                         if (error)
775                                 goto out_unlock_internal;
776                 }
777
778                 if (need_i_mutex) {
779                         /* demote the lock now the cached pages are gone */
780                         XFS_ILOCK_DEMOTE(mp, io, XFS_IOLOCK_EXCL);
781                         mutex_unlock(&inode->i_mutex);
782
783                         iolock = XFS_IOLOCK_SHARED;
784                         locktype = VRWLOCK_WRITE_DIRECT;
785                         need_i_mutex = 0;
786                 }
787
788                 xfs_rw_enter_trace(XFS_DIOWR_ENTER, io, (void *)iovp, segs,
789                                 *offset, ioflags);
790                 ret = generic_file_direct_write(iocb, iovp,
791                                 &segs, pos, offset, count, ocount);
792
793                 /*
794                  * direct-io write to a hole: fall through to buffered I/O
795                  * for completing the rest of the request.
796                  */
797                 if (ret >= 0 && ret != count) {
798                         XFS_STATS_ADD(xs_write_bytes, ret);
799
800                         pos += ret;
801                         count -= ret;
802
803                         ioflags &= ~IO_ISDIRECT;
804                         xfs_iunlock(xip, iolock);
805                         goto relock;
806                 }
807         } else {
808                 xfs_rw_enter_trace(XFS_WRITE_ENTER, io, (void *)iovp, segs,
809                                 *offset, ioflags);
810                 ret = generic_file_buffered_write(iocb, iovp, segs,
811                                 pos, offset, count, ret);
812         }
813
814         current->backing_dev_info = NULL;
815
816         if (ret == -EIOCBQUEUED && !(ioflags & IO_ISAIO))
817                 ret = wait_on_sync_kiocb(iocb);
818
819         if ((ret == -ENOSPC) &&
820             DM_EVENT_ENABLED(vp->v_vfsp, xip, DM_EVENT_NOSPACE) &&
821             !(ioflags & IO_INVIS)) {
822
823                 xfs_rwunlock(bdp, locktype);
824                 if (need_i_mutex)
825                         mutex_unlock(&inode->i_mutex);
826                 error = XFS_SEND_NAMESP(xip->i_mount, DM_EVENT_NOSPACE, vp,
827                                 DM_RIGHT_NULL, vp, DM_RIGHT_NULL, NULL, NULL,
828                                 0, 0, 0); /* Delay flag intentionally  unused */
829                 if (need_i_mutex)
830                         mutex_lock(&inode->i_mutex);
831                 xfs_rwlock(bdp, locktype);
832                 if (error)
833                         goto out_unlock_internal;
834                 pos = xip->i_size;
835                 ret = 0;
836                 goto retry;
837         }
838
839         isize = i_size_read(inode);
840         if (unlikely(ret < 0 && ret != -EFAULT && *offset > isize))
841                 *offset = isize;
842
843         if (*offset > xip->i_size) {
844                 xfs_ilock(xip, XFS_ILOCK_EXCL);
845                 if (*offset > xip->i_size)
846                         xip->i_size = *offset;
847                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
848         }
849
850         error = -ret;
851         if (ret <= 0)
852                 goto out_unlock_internal;
853
854         XFS_STATS_ADD(xs_write_bytes, ret);
855
856         /* Handle various SYNC-type writes */
857         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
858                 error = xfs_write_sync_logforce(mp, xip);
859                 if (error)
860                         goto out_unlock_internal;
861
862                 xfs_rwunlock(bdp, locktype);
863                 if (need_i_mutex)
864                         mutex_unlock(&inode->i_mutex);
865
866                 error = sync_page_range(inode, mapping, pos, ret);
867                 if (!error)
868                         error = -ret;
869                 if (need_i_mutex)
870                         mutex_lock(&inode->i_mutex);
871                 xfs_rwlock(bdp, locktype);
872         }
873
874  out_unlock_internal:
875         if (io->io_new_size) {
876                 xfs_ilock(xip, XFS_ILOCK_EXCL);
877                 io->io_new_size = 0;
878                 /*
879                  * If this was a direct or synchronous I/O that failed (such
880                  * as ENOSPC) then part of the I/O may have been written to
881                  * disk before the error occured.  In this case the on-disk
882                  * file size may have been adjusted beyond the in-memory file
883                  * size and now needs to be truncated back.
884                  */
885                 if (xip->i_d.di_size > xip->i_size)
886                         xip->i_d.di_size = xip->i_size;
887                 xfs_iunlock(xip, XFS_ILOCK_EXCL);
888         }
889         xfs_rwunlock(bdp, locktype);
890  out_unlock_mutex:
891         if (need_i_mutex)
892                 mutex_unlock(&inode->i_mutex);
893         return -error;
894 }
895
896 /*
897  * All xfs metadata buffers except log state machine buffers
898  * get this attached as their b_bdstrat callback function.
899  * This is so that we can catch a buffer
900  * after prematurely unpinning it to forcibly shutdown the filesystem.
901  */
902 int
903 xfs_bdstrat_cb(struct xfs_buf *bp)
904 {
905         xfs_mount_t     *mp;
906
907         mp = XFS_BUF_FSPRIVATE3(bp, xfs_mount_t *);
908         if (!XFS_FORCED_SHUTDOWN(mp)) {
909                 xfs_buf_iorequest(bp);
910                 return 0;
911         } else {
912                 xfs_buftrace("XFS__BDSTRAT IOERROR", bp);
913                 /*
914                  * Metadata write that didn't get logged but
915                  * written delayed anyway. These aren't associated
916                  * with a transaction, and can be ignored.
917                  */
918                 if (XFS_BUF_IODONE_FUNC(bp) == NULL &&
919                     (XFS_BUF_ISREAD(bp)) == 0)
920                         return (xfs_bioerror_relse(bp));
921                 else
922                         return (xfs_bioerror(bp));
923         }
924 }
925
926
927 int
928 xfs_bmap(bhv_desc_t     *bdp,
929         xfs_off_t       offset,
930         ssize_t         count,
931         int             flags,
932         xfs_iomap_t     *iomapp,
933         int             *niomaps)
934 {
935         xfs_inode_t     *ip = XFS_BHVTOI(bdp);
936         xfs_iocore_t    *io = &ip->i_iocore;
937
938         ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
939         ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
940                ((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
941
942         return xfs_iomap(io, offset, count, flags, iomapp, niomaps);
943 }
944
945 /*
946  * Wrapper around bdstrat so that we can stop data
947  * from going to disk in case we are shutting down the filesystem.
948  * Typically user data goes thru this path; one of the exceptions
949  * is the superblock.
950  */
951 int
952 xfsbdstrat(
953         struct xfs_mount        *mp,
954         struct xfs_buf          *bp)
955 {
956         ASSERT(mp);
957         if (!XFS_FORCED_SHUTDOWN(mp)) {
958                 /* Grio redirection would go here
959                  * if (XFS_BUF_IS_GRIO(bp)) {
960                  */
961
962                 xfs_buf_iorequest(bp);
963                 return 0;
964         }
965
966         xfs_buftrace("XFSBDSTRAT IOERROR", bp);
967         return (xfs_bioerror_relse(bp));
968 }
969
970 /*
971  * If the underlying (data/log/rt) device is readonly, there are some
972  * operations that cannot proceed.
973  */
974 int
975 xfs_dev_is_read_only(
976         xfs_mount_t             *mp,
977         char                    *message)
978 {
979         if (xfs_readonly_buftarg(mp->m_ddev_targp) ||
980             xfs_readonly_buftarg(mp->m_logdev_targp) ||
981             (mp->m_rtdev_targp && xfs_readonly_buftarg(mp->m_rtdev_targp))) {
982                 cmn_err(CE_NOTE,
983                         "XFS: %s required on read-only device.", message);
984                 cmn_err(CE_NOTE,
985                         "XFS: write access unavailable, cannot proceed.");
986                 return EROFS;
987         }
988         return 0;
989 }