cde70e8954439fd205f5ff72a5087d4739c1d0ce
[linux-2.6.git] / fs / xfs / xfs_iomap.c
1 /*
2  * Copyright (c) 2000-2006 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_ialloc.h"
39 #include "xfs_btree.h"
40 #include "xfs_bmap.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_buf_item.h"
48 #include "xfs_trans_space.h"
49 #include "xfs_utils.h"
50 #include "xfs_iomap.h"
51
52 #if defined(XFS_RW_TRACE)
53 void
54 xfs_iomap_enter_trace(
55         int             tag,
56         xfs_iocore_t    *io,
57         xfs_off_t       offset,
58         ssize_t         count)
59 {
60         xfs_inode_t     *ip = XFS_IO_INODE(io);
61
62         if (!ip->i_rwtrace)
63                 return;
64
65         ktrace_enter(ip->i_rwtrace,
66                 (void *)((unsigned long)tag),
67                 (void *)ip,
68                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
69                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
70                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
71                 (void *)((unsigned long)(offset & 0xffffffff)),
72                 (void *)((unsigned long)count),
73                 (void *)((unsigned long)((io->io_new_size >> 32) & 0xffffffff)),
74                 (void *)((unsigned long)(io->io_new_size & 0xffffffff)),
75                 (void *)((unsigned long)current_pid()),
76                 (void *)NULL,
77                 (void *)NULL,
78                 (void *)NULL,
79                 (void *)NULL,
80                 (void *)NULL,
81                 (void *)NULL);
82 }
83
84 void
85 xfs_iomap_map_trace(
86         int             tag,
87         xfs_iocore_t    *io,
88         xfs_off_t       offset,
89         ssize_t         count,
90         xfs_iomap_t     *iomapp,
91         xfs_bmbt_irec_t *imapp,
92         int             flags)
93 {
94         xfs_inode_t     *ip = XFS_IO_INODE(io);
95
96         if (!ip->i_rwtrace)
97                 return;
98
99         ktrace_enter(ip->i_rwtrace,
100                 (void *)((unsigned long)tag),
101                 (void *)ip,
102                 (void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
103                 (void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
104                 (void *)((unsigned long)((offset >> 32) & 0xffffffff)),
105                 (void *)((unsigned long)(offset & 0xffffffff)),
106                 (void *)((unsigned long)count),
107                 (void *)((unsigned long)flags),
108                 (void *)((unsigned long)((iomapp->iomap_offset >> 32) & 0xffffffff)),
109                 (void *)((unsigned long)(iomapp->iomap_offset & 0xffffffff)),
110                 (void *)((unsigned long)(iomapp->iomap_delta)),
111                 (void *)((unsigned long)(iomapp->iomap_bsize)),
112                 (void *)((unsigned long)(iomapp->iomap_bn)),
113                 (void *)(__psint_t)(imapp->br_startoff),
114                 (void *)((unsigned long)(imapp->br_blockcount)),
115                 (void *)(__psint_t)(imapp->br_startblock));
116 }
117 #else
118 #define xfs_iomap_enter_trace(tag, io, offset, count)
119 #define xfs_iomap_map_trace(tag, io, offset, count, iomapp, imapp, flags)
120 #endif
121
122 #define XFS_WRITEIO_ALIGN(mp,off)       (((off) >> mp->m_writeio_log) \
123                                                 << mp->m_writeio_log)
124 #define XFS_STRAT_WRITE_IMAPS   2
125 #define XFS_WRITE_IMAPS         XFS_BMAP_MAX_NMAP
126
127 STATIC int
128 xfs_imap_to_bmap(
129         xfs_iocore_t    *io,
130         xfs_off_t       offset,
131         xfs_bmbt_irec_t *imap,
132         xfs_iomap_t     *iomapp,
133         int             imaps,                  /* Number of imap entries */
134         int             iomaps,                 /* Number of iomap entries */
135         int             flags)
136 {
137         xfs_mount_t     *mp;
138         xfs_fsize_t     nisize;
139         int             pbm;
140         xfs_fsblock_t   start_block;
141
142         mp = io->io_mount;
143         nisize = XFS_SIZE(mp, io);
144         if (io->io_new_size > nisize)
145                 nisize = io->io_new_size;
146
147         for (pbm = 0; imaps && pbm < iomaps; imaps--, iomapp++, imap++, pbm++) {
148                 iomapp->iomap_offset = XFS_FSB_TO_B(mp, imap->br_startoff);
149                 iomapp->iomap_delta = offset - iomapp->iomap_offset;
150                 iomapp->iomap_bsize = XFS_FSB_TO_B(mp, imap->br_blockcount);
151                 iomapp->iomap_flags = flags;
152
153                 if (io->io_flags & XFS_IOCORE_RT) {
154                         iomapp->iomap_flags |= IOMAP_REALTIME;
155                         iomapp->iomap_target = mp->m_rtdev_targp;
156                 } else {
157                         iomapp->iomap_target = mp->m_ddev_targp;
158                 }
159                 start_block = imap->br_startblock;
160                 if (start_block == HOLESTARTBLOCK) {
161                         iomapp->iomap_bn = IOMAP_DADDR_NULL;
162                         iomapp->iomap_flags |= IOMAP_HOLE;
163                 } else if (start_block == DELAYSTARTBLOCK) {
164                         iomapp->iomap_bn = IOMAP_DADDR_NULL;
165                         iomapp->iomap_flags |= IOMAP_DELAY;
166                 } else {
167                         iomapp->iomap_bn = XFS_FSB_TO_DB_IO(io, start_block);
168                         if (ISUNWRITTEN(imap))
169                                 iomapp->iomap_flags |= IOMAP_UNWRITTEN;
170                 }
171
172                 if ((iomapp->iomap_offset + iomapp->iomap_bsize) >= nisize) {
173                         iomapp->iomap_flags |= IOMAP_EOF;
174                 }
175
176                 offset += iomapp->iomap_bsize - iomapp->iomap_delta;
177         }
178         return pbm;     /* Return the number filled */
179 }
180
181 int
182 xfs_iomap(
183         xfs_iocore_t    *io,
184         xfs_off_t       offset,
185         ssize_t         count,
186         int             flags,
187         xfs_iomap_t     *iomapp,
188         int             *niomaps)
189 {
190         xfs_mount_t     *mp = io->io_mount;
191         xfs_fileoff_t   offset_fsb, end_fsb;
192         int             error = 0;
193         int             lockmode = 0;
194         xfs_bmbt_irec_t imap;
195         int             nimaps = 1;
196         int             bmapi_flags = 0;
197         int             iomap_flags = 0;
198
199         if (XFS_FORCED_SHUTDOWN(mp))
200                 return XFS_ERROR(EIO);
201
202         switch (flags &
203                 (BMAPI_READ | BMAPI_WRITE | BMAPI_ALLOCATE |
204                  BMAPI_UNWRITTEN | BMAPI_DEVICE)) {
205         case BMAPI_READ:
206                 xfs_iomap_enter_trace(XFS_IOMAP_READ_ENTER, io, offset, count);
207                 lockmode = XFS_LCK_MAP_SHARED(mp, io);
208                 bmapi_flags = XFS_BMAPI_ENTIRE;
209                 break;
210         case BMAPI_WRITE:
211                 xfs_iomap_enter_trace(XFS_IOMAP_WRITE_ENTER, io, offset, count);
212                 lockmode = XFS_ILOCK_EXCL|XFS_EXTSIZE_WR;
213                 if (flags & BMAPI_IGNSTATE)
214                         bmapi_flags |= XFS_BMAPI_IGSTATE|XFS_BMAPI_ENTIRE;
215                 XFS_ILOCK(mp, io, lockmode);
216                 break;
217         case BMAPI_ALLOCATE:
218                 xfs_iomap_enter_trace(XFS_IOMAP_ALLOC_ENTER, io, offset, count);
219                 lockmode = XFS_ILOCK_SHARED|XFS_EXTSIZE_RD;
220                 bmapi_flags = XFS_BMAPI_ENTIRE;
221                 /* Attempt non-blocking lock */
222                 if (flags & BMAPI_TRYLOCK) {
223                         if (!XFS_ILOCK_NOWAIT(mp, io, lockmode))
224                                 return XFS_ERROR(EAGAIN);
225                 } else {
226                         XFS_ILOCK(mp, io, lockmode);
227                 }
228                 break;
229         case BMAPI_UNWRITTEN:
230                 goto phase2;
231         case BMAPI_DEVICE:
232                 lockmode = XFS_LCK_MAP_SHARED(mp, io);
233                 iomapp->iomap_target = io->io_flags & XFS_IOCORE_RT ?
234                         mp->m_rtdev_targp : mp->m_ddev_targp;
235                 error = 0;
236                 *niomaps = 1;
237                 goto out;
238         default:
239                 BUG();
240         }
241
242         ASSERT(offset <= mp->m_maxioffset);
243         if ((xfs_fsize_t)offset + count > mp->m_maxioffset)
244                 count = mp->m_maxioffset - offset;
245         end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
246         offset_fsb = XFS_B_TO_FSBT(mp, offset);
247
248         error = XFS_BMAPI(mp, NULL, io, offset_fsb,
249                         (xfs_filblks_t)(end_fsb - offset_fsb),
250                         bmapi_flags,  NULL, 0, &imap,
251                         &nimaps, NULL, NULL);
252
253         if (error)
254                 goto out;
255
256 phase2:
257         switch (flags & (BMAPI_WRITE|BMAPI_ALLOCATE|BMAPI_UNWRITTEN)) {
258         case BMAPI_WRITE:
259                 /* If we found an extent, return it */
260                 if (nimaps &&
261                     (imap.br_startblock != HOLESTARTBLOCK) &&
262                     (imap.br_startblock != DELAYSTARTBLOCK)) {
263                         xfs_iomap_map_trace(XFS_IOMAP_WRITE_MAP, io,
264                                         offset, count, iomapp, &imap, flags);
265                         break;
266                 }
267
268                 if (flags & (BMAPI_DIRECT|BMAPI_MMAP)) {
269                         error = XFS_IOMAP_WRITE_DIRECT(mp, io, offset,
270                                         count, flags, &imap, &nimaps, nimaps);
271                 } else {
272                         error = XFS_IOMAP_WRITE_DELAY(mp, io, offset, count,
273                                         flags, &imap, &nimaps);
274                 }
275                 if (!error) {
276                         xfs_iomap_map_trace(XFS_IOMAP_ALLOC_MAP, io,
277                                         offset, count, iomapp, &imap, flags);
278                 }
279                 iomap_flags = IOMAP_NEW;
280                 break;
281         case BMAPI_ALLOCATE:
282                 /* If we found an extent, return it */
283                 XFS_IUNLOCK(mp, io, lockmode);
284                 lockmode = 0;
285
286                 if (nimaps && !ISNULLSTARTBLOCK(imap.br_startblock)) {
287                         xfs_iomap_map_trace(XFS_IOMAP_WRITE_MAP, io,
288                                         offset, count, iomapp, &imap, flags);
289                         break;
290                 }
291
292                 error = XFS_IOMAP_WRITE_ALLOCATE(mp, io, offset, count,
293                                                  &imap, &nimaps);
294                 break;
295         case BMAPI_UNWRITTEN:
296                 lockmode = 0;
297                 error = XFS_IOMAP_WRITE_UNWRITTEN(mp, io, offset, count);
298                 nimaps = 0;
299                 break;
300         }
301
302         if (nimaps) {
303                 *niomaps = xfs_imap_to_bmap(io, offset, &imap,
304                                             iomapp, nimaps, *niomaps, iomap_flags);
305         } else if (niomaps) {
306                 *niomaps = 0;
307         }
308
309 out:
310         if (lockmode)
311                 XFS_IUNLOCK(mp, io, lockmode);
312         return XFS_ERROR(error);
313 }
314
315 STATIC int
316 xfs_iomap_eof_align_last_fsb(
317         xfs_mount_t     *mp,
318         xfs_iocore_t    *io,
319         xfs_fsize_t     isize,
320         xfs_extlen_t    extsize,
321         xfs_fileoff_t   *last_fsb)
322 {
323         xfs_fileoff_t   new_last_fsb = 0;
324         xfs_extlen_t    align;
325         int             eof, error;
326
327         if (io->io_flags & XFS_IOCORE_RT)
328                 ;
329         /*
330          * If mounted with the "-o swalloc" option, roundup the allocation
331          * request to a stripe width boundary if the file size is >=
332          * stripe width and we are allocating past the allocation eof.
333          */
334         else if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC) &&
335                 (isize >= XFS_FSB_TO_B(mp, mp->m_swidth)))
336                 new_last_fsb = roundup_64(*last_fsb, mp->m_swidth);
337         /*
338          * Roundup the allocation request to a stripe unit (m_dalign) boundary
339          * if the file size is >= stripe unit size, and we are allocating past
340          * the allocation eof.
341          */
342         else if (mp->m_dalign && (isize >= XFS_FSB_TO_B(mp, mp->m_dalign)))
343                 new_last_fsb = roundup_64(*last_fsb, mp->m_dalign);
344
345         /*
346          * Always round up the allocation request to an extent boundary
347          * (when file on a real-time subvolume or has di_extsize hint).
348          */
349         if (extsize) {
350                 if (new_last_fsb)
351                         align = roundup_64(new_last_fsb, extsize);
352                 else
353                         align = extsize;
354                 new_last_fsb = roundup_64(*last_fsb, align);
355         }
356
357         if (new_last_fsb) {
358                 error = XFS_BMAP_EOF(mp, io, new_last_fsb, XFS_DATA_FORK, &eof);
359                 if (error)
360                         return error;
361                 if (eof)
362                         *last_fsb = new_last_fsb;
363         }
364         return 0;
365 }
366
367 STATIC int
368 xfs_flush_space(
369         xfs_inode_t     *ip,
370         int             *fsynced,
371         int             *ioflags)
372 {
373         switch (*fsynced) {
374         case 0:
375                 if (ip->i_delayed_blks) {
376                         xfs_iunlock(ip, XFS_ILOCK_EXCL);
377                         xfs_flush_inode(ip);
378                         xfs_ilock(ip, XFS_ILOCK_EXCL);
379                         *fsynced = 1;
380                 } else {
381                         *ioflags |= BMAPI_SYNC;
382                         *fsynced = 2;
383                 }
384                 return 0;
385         case 1:
386                 *fsynced = 2;
387                 *ioflags |= BMAPI_SYNC;
388                 return 0;
389         case 2:
390                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
391                 xfs_flush_device(ip);
392                 xfs_ilock(ip, XFS_ILOCK_EXCL);
393                 *fsynced = 3;
394                 return 0;
395         }
396         return 1;
397 }
398
399 STATIC int
400 xfs_cmn_err_fsblock_zero(
401         xfs_inode_t     *ip,
402         xfs_bmbt_irec_t *imap)
403 {
404         xfs_cmn_err(XFS_PTAG_FSBLOCK_ZERO, CE_ALERT, ip->i_mount,
405                         "Access to block zero in inode %llu "
406                         "start_block: %llx start_off: %llx "
407                         "blkcnt: %llx extent-state: %x\n",
408                 (unsigned long long)ip->i_ino,
409                 (unsigned long long)imap->br_startblock,
410                 (unsigned long long)imap->br_startoff,
411                 (unsigned long long)imap->br_blockcount,
412                 imap->br_state);
413         return EFSCORRUPTED;
414 }
415
416 int
417 xfs_iomap_write_direct(
418         xfs_inode_t     *ip,
419         xfs_off_t       offset,
420         size_t          count,
421         int             flags,
422         xfs_bmbt_irec_t *ret_imap,
423         int             *nmaps,
424         int             found)
425 {
426         xfs_mount_t     *mp = ip->i_mount;
427         xfs_iocore_t    *io = &ip->i_iocore;
428         xfs_fileoff_t   offset_fsb;
429         xfs_fileoff_t   last_fsb;
430         xfs_filblks_t   count_fsb, resaligned;
431         xfs_fsblock_t   firstfsb;
432         xfs_extlen_t    extsz, temp;
433         xfs_fsize_t     isize;
434         int             nimaps;
435         int             bmapi_flag;
436         int             quota_flag;
437         int             rt;
438         xfs_trans_t     *tp;
439         xfs_bmbt_irec_t imap;
440         xfs_bmap_free_t free_list;
441         uint            qblocks, resblks, resrtextents;
442         int             committed;
443         int             error;
444
445         /*
446          * Make sure that the dquots are there. This doesn't hold
447          * the ilock across a disk read.
448          */
449         error = XFS_QM_DQATTACH(ip->i_mount, ip, XFS_QMOPT_ILOCKED);
450         if (error)
451                 return XFS_ERROR(error);
452
453         rt = XFS_IS_REALTIME_INODE(ip);
454         if (unlikely(rt)) {
455                 if (!(extsz = ip->i_d.di_extsize))
456                         extsz = mp->m_sb.sb_rextsize;
457         } else {
458                 extsz = ip->i_d.di_extsize;
459         }
460
461         isize = ip->i_d.di_size;
462         if (io->io_new_size > isize)
463                 isize = io->io_new_size;
464
465         offset_fsb = XFS_B_TO_FSBT(mp, offset);
466         last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
467         if ((offset + count) > isize) {
468                 error = xfs_iomap_eof_align_last_fsb(mp, io, isize, extsz,
469                                                         &last_fsb);
470                 if (error)
471                         goto error_out;
472         } else {
473                 if (found && (ret_imap->br_startblock == HOLESTARTBLOCK))
474                         last_fsb = MIN(last_fsb, (xfs_fileoff_t)
475                                         ret_imap->br_blockcount +
476                                         ret_imap->br_startoff);
477         }
478         count_fsb = last_fsb - offset_fsb;
479         ASSERT(count_fsb > 0);
480
481         resaligned = count_fsb;
482         if (unlikely(extsz)) {
483                 if ((temp = do_mod(offset_fsb, extsz)))
484                         resaligned += temp;
485                 if ((temp = do_mod(resaligned, extsz)))
486                         resaligned += extsz - temp;
487         }
488
489         if (unlikely(rt)) {
490                 resrtextents = qblocks = resaligned;
491                 resrtextents /= mp->m_sb.sb_rextsize;
492                 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
493                 quota_flag = XFS_QMOPT_RES_RTBLKS;
494         } else {
495                 resrtextents = 0;
496                 resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
497                 quota_flag = XFS_QMOPT_RES_REGBLKS;
498         }
499
500         /*
501          * Allocate and setup the transaction
502          */
503         xfs_iunlock(ip, XFS_ILOCK_EXCL);
504         tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
505         error = xfs_trans_reserve(tp, resblks,
506                         XFS_WRITE_LOG_RES(mp), resrtextents,
507                         XFS_TRANS_PERM_LOG_RES,
508                         XFS_WRITE_LOG_COUNT);
509         /*
510          * Check for running out of space, note: need lock to return
511          */
512         if (error)
513                 xfs_trans_cancel(tp, 0);
514         xfs_ilock(ip, XFS_ILOCK_EXCL);
515         if (error)
516                 goto error_out;
517
518         error = XFS_TRANS_RESERVE_QUOTA_NBLKS(mp, tp, ip,
519                                               qblocks, 0, quota_flag);
520         if (error)
521                 goto error1;
522
523         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
524         xfs_trans_ihold(tp, ip);
525
526         bmapi_flag = XFS_BMAPI_WRITE;
527         if ((flags & BMAPI_DIRECT) && (offset < ip->i_d.di_size || extsz))
528                 bmapi_flag |= XFS_BMAPI_PREALLOC;
529
530         /*
531          * Issue the xfs_bmapi() call to allocate the blocks
532          */
533         XFS_BMAP_INIT(&free_list, &firstfsb);
534         nimaps = 1;
535         error = XFS_BMAPI(mp, tp, io, offset_fsb, count_fsb, bmapi_flag,
536                 &firstfsb, 0, &imap, &nimaps, &free_list, NULL);
537         if (error)
538                 goto error0;
539
540         /*
541          * Complete the transaction
542          */
543         error = xfs_bmap_finish(&tp, &free_list, &committed);
544         if (error)
545                 goto error0;
546         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
547         if (error)
548                 goto error_out;
549
550         /*
551          * Copy any maps to caller's array and return any error.
552          */
553         if (nimaps == 0) {
554                 error = ENOSPC;
555                 goto error_out;
556         }
557
558         if (unlikely(!imap.br_startblock && !(io->io_flags & XFS_IOCORE_RT))) {
559                 error = xfs_cmn_err_fsblock_zero(ip, &imap);
560                 goto error_out;
561         }
562
563         *ret_imap = imap;
564         *nmaps = 1;
565         return 0;
566
567 error0: /* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
568         xfs_bmap_cancel(&free_list);
569         XFS_TRANS_UNRESERVE_QUOTA_NBLKS(mp, tp, ip, qblocks, 0, quota_flag);
570
571 error1: /* Just cancel transaction */
572         xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
573         *nmaps = 0;     /* nothing set-up here */
574
575 error_out:
576         return XFS_ERROR(error);
577 }
578
579 /*
580  * If the caller is doing a write at the end of the file,
581  * then extend the allocation out to the file system's write
582  * iosize.  We clean up any extra space left over when the
583  * file is closed in xfs_inactive().
584  *
585  * For sync writes, we are flushing delayed allocate space to
586  * try to make additional space available for allocation near
587  * the filesystem full boundary - preallocation hurts in that
588  * situation, of course.
589  */
590 STATIC int
591 xfs_iomap_eof_want_preallocate(
592         xfs_mount_t     *mp,
593         xfs_iocore_t    *io,
594         xfs_fsize_t     isize,
595         xfs_off_t       offset,
596         size_t          count,
597         int             ioflag,
598         xfs_bmbt_irec_t *imap,
599         int             nimaps,
600         int             *prealloc)
601 {
602         xfs_fileoff_t   start_fsb;
603         xfs_filblks_t   count_fsb;
604         xfs_fsblock_t   firstblock;
605         int             n, error, imaps;
606
607         *prealloc = 0;
608         if ((ioflag & BMAPI_SYNC) || (offset + count) <= isize)
609                 return 0;
610
611         /*
612          * If there are any real blocks past eof, then don't
613          * do any speculative allocation.
614          */
615         start_fsb = XFS_B_TO_FSBT(mp, ((xfs_ufsize_t)(offset + count - 1)));
616         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
617         while (count_fsb > 0) {
618                 imaps = nimaps;
619                 firstblock = NULLFSBLOCK;
620                 error = XFS_BMAPI(mp, NULL, io, start_fsb, count_fsb, 0,
621                                   &firstblock, 0, imap, &imaps, NULL, NULL);
622                 if (error)
623                         return error;
624                 for (n = 0; n < imaps; n++) {
625                         if ((imap[n].br_startblock != HOLESTARTBLOCK) &&
626                             (imap[n].br_startblock != DELAYSTARTBLOCK))
627                                 return 0;
628                         start_fsb += imap[n].br_blockcount;
629                         count_fsb -= imap[n].br_blockcount;
630                 }
631         }
632         *prealloc = 1;
633         return 0;
634 }
635
636 int
637 xfs_iomap_write_delay(
638         xfs_inode_t     *ip,
639         xfs_off_t       offset,
640         size_t          count,
641         int             ioflag,
642         xfs_bmbt_irec_t *ret_imap,
643         int             *nmaps)
644 {
645         xfs_mount_t     *mp = ip->i_mount;
646         xfs_iocore_t    *io = &ip->i_iocore;
647         xfs_fileoff_t   offset_fsb;
648         xfs_fileoff_t   last_fsb;
649         xfs_off_t       aligned_offset;
650         xfs_fileoff_t   ioalign;
651         xfs_fsblock_t   firstblock;
652         xfs_extlen_t    extsz;
653         xfs_fsize_t     isize;
654         int             nimaps;
655         xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];
656         int             prealloc, fsynced = 0;
657         int             error;
658
659         ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE) != 0);
660
661         /*
662          * Make sure that the dquots are there. This doesn't hold
663          * the ilock across a disk read.
664          */
665         error = XFS_QM_DQATTACH(mp, ip, XFS_QMOPT_ILOCKED);
666         if (error)
667                 return XFS_ERROR(error);
668
669         if (XFS_IS_REALTIME_INODE(ip)) {
670                 if (!(extsz = ip->i_d.di_extsize))
671                         extsz = mp->m_sb.sb_rextsize;
672         } else {
673                 extsz = ip->i_d.di_extsize;
674         }
675
676         offset_fsb = XFS_B_TO_FSBT(mp, offset);
677
678 retry:
679         isize = ip->i_d.di_size;
680         if (io->io_new_size > isize)
681                 isize = io->io_new_size;
682
683         error = xfs_iomap_eof_want_preallocate(mp, io, isize, offset, count,
684                                 ioflag, imap, XFS_WRITE_IMAPS, &prealloc);
685         if (error)
686                 return error;
687
688         if (prealloc) {
689                 aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1));
690                 ioalign = XFS_B_TO_FSBT(mp, aligned_offset);
691                 last_fsb = ioalign + mp->m_writeio_blocks;
692         } else {
693                 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
694         }
695
696         if (prealloc || extsz) {
697                 error = xfs_iomap_eof_align_last_fsb(mp, io, isize, extsz,
698                                                         &last_fsb);
699                 if (error)
700                         return error;
701         }
702
703         nimaps = XFS_WRITE_IMAPS;
704         firstblock = NULLFSBLOCK;
705         error = XFS_BMAPI(mp, NULL, io, offset_fsb,
706                           (xfs_filblks_t)(last_fsb - offset_fsb),
707                           XFS_BMAPI_DELAY | XFS_BMAPI_WRITE |
708                           XFS_BMAPI_ENTIRE, &firstblock, 1, imap,
709                           &nimaps, NULL, NULL);
710         if (error && (error != ENOSPC))
711                 return XFS_ERROR(error);
712
713         /*
714          * If bmapi returned us nothing, and if we didn't get back EDQUOT,
715          * then we must have run out of space - flush delalloc, and retry..
716          */
717         if (nimaps == 0) {
718                 xfs_iomap_enter_trace(XFS_IOMAP_WRITE_NOSPACE,
719                                         io, offset, count);
720                 if (xfs_flush_space(ip, &fsynced, &ioflag))
721                         return XFS_ERROR(ENOSPC);
722
723                 error = 0;
724                 goto retry;
725         }
726
727         if (unlikely(!imap[0].br_startblock && !(io->io_flags & XFS_IOCORE_RT)))
728                 return xfs_cmn_err_fsblock_zero(ip, &imap[0]);
729
730         *ret_imap = imap[0];
731         *nmaps = 1;
732
733         return 0;
734 }
735
736 /*
737  * Pass in a delayed allocate extent, convert it to real extents;
738  * return to the caller the extent we create which maps on top of
739  * the originating callers request.
740  *
741  * Called without a lock on the inode.
742  */
743 int
744 xfs_iomap_write_allocate(
745         xfs_inode_t     *ip,
746         xfs_off_t       offset,
747         size_t          count,
748         xfs_bmbt_irec_t *map,
749         int             *retmap)
750 {
751         xfs_mount_t     *mp = ip->i_mount;
752         xfs_iocore_t    *io = &ip->i_iocore;
753         xfs_fileoff_t   offset_fsb, last_block;
754         xfs_fileoff_t   end_fsb, map_start_fsb;
755         xfs_fsblock_t   first_block;
756         xfs_bmap_free_t free_list;
757         xfs_filblks_t   count_fsb;
758         xfs_bmbt_irec_t imap[XFS_STRAT_WRITE_IMAPS];
759         xfs_trans_t     *tp;
760         int             i, nimaps, committed;
761         int             error = 0;
762         int             nres;
763
764         *retmap = 0;
765
766         /*
767          * Make sure that the dquots are there.
768          */
769         if ((error = XFS_QM_DQATTACH(mp, ip, 0)))
770                 return XFS_ERROR(error);
771
772         offset_fsb = XFS_B_TO_FSBT(mp, offset);
773         count_fsb = map->br_blockcount;
774         map_start_fsb = map->br_startoff;
775
776         XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
777
778         while (count_fsb != 0) {
779                 /*
780                  * Set up a transaction with which to allocate the
781                  * backing store for the file.  Do allocations in a
782                  * loop until we get some space in the range we are
783                  * interested in.  The other space that might be allocated
784                  * is in the delayed allocation extent on which we sit
785                  * but before our buffer starts.
786                  */
787
788                 nimaps = 0;
789                 while (nimaps == 0) {
790                         tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
791                         nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
792                         error = xfs_trans_reserve(tp, nres,
793                                         XFS_WRITE_LOG_RES(mp),
794                                         0, XFS_TRANS_PERM_LOG_RES,
795                                         XFS_WRITE_LOG_COUNT);
796                         if (error == ENOSPC) {
797                                 error = xfs_trans_reserve(tp, 0,
798                                                 XFS_WRITE_LOG_RES(mp),
799                                                 0,
800                                                 XFS_TRANS_PERM_LOG_RES,
801                                                 XFS_WRITE_LOG_COUNT);
802                         }
803                         if (error) {
804                                 xfs_trans_cancel(tp, 0);
805                                 return XFS_ERROR(error);
806                         }
807                         xfs_ilock(ip, XFS_ILOCK_EXCL);
808                         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
809                         xfs_trans_ihold(tp, ip);
810
811                         XFS_BMAP_INIT(&free_list, &first_block);
812
813                         nimaps = XFS_STRAT_WRITE_IMAPS;
814                         /*
815                          * Ensure we don't go beyond eof - it is possible
816                          * the extents changed since we did the read call,
817                          * we dropped the ilock in the interim.
818                          */
819
820                         end_fsb = XFS_B_TO_FSB(mp, ip->i_d.di_size);
821                         xfs_bmap_last_offset(NULL, ip, &last_block,
822                                 XFS_DATA_FORK);
823                         last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
824                         if ((map_start_fsb + count_fsb) > last_block) {
825                                 count_fsb = last_block - map_start_fsb;
826                                 if (count_fsb == 0) {
827                                         error = EAGAIN;
828                                         goto trans_cancel;
829                                 }
830                         }
831
832                         /* Go get the actual blocks */
833                         error = XFS_BMAPI(mp, tp, io, map_start_fsb, count_fsb,
834                                         XFS_BMAPI_WRITE, &first_block, 1,
835                                         imap, &nimaps, &free_list, NULL);
836                         if (error)
837                                 goto trans_cancel;
838
839                         error = xfs_bmap_finish(&tp, &free_list, &committed);
840                         if (error)
841                                 goto trans_cancel;
842
843                         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
844                         if (error)
845                                 goto error0;
846
847                         xfs_iunlock(ip, XFS_ILOCK_EXCL);
848                 }
849
850                 /*
851                  * See if we were able to allocate an extent that
852                  * covers at least part of the callers request
853                  */
854                 for (i = 0; i < nimaps; i++) {
855                         if (unlikely(!imap[i].br_startblock &&
856                                      !(io->io_flags & XFS_IOCORE_RT)))
857                                 return xfs_cmn_err_fsblock_zero(ip, &imap[i]);
858                         if ((offset_fsb >= imap[i].br_startoff) &&
859                             (offset_fsb < (imap[i].br_startoff +
860                                            imap[i].br_blockcount))) {
861                                 *map = imap[i];
862                                 *retmap = 1;
863                                 XFS_STATS_INC(xs_xstrat_quick);
864                                 return 0;
865                         }
866                         count_fsb -= imap[i].br_blockcount;
867                 }
868
869                 /* So far we have not mapped the requested part of the
870                  * file, just surrounding data, try again.
871                  */
872                 nimaps--;
873                 map_start_fsb = imap[nimaps].br_startoff +
874                                 imap[nimaps].br_blockcount;
875         }
876
877 trans_cancel:
878         xfs_bmap_cancel(&free_list);
879         xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
880 error0:
881         xfs_iunlock(ip, XFS_ILOCK_EXCL);
882         return XFS_ERROR(error);
883 }
884
885 int
886 xfs_iomap_write_unwritten(
887         xfs_inode_t     *ip,
888         xfs_off_t       offset,
889         size_t          count)
890 {
891         xfs_mount_t     *mp = ip->i_mount;
892         xfs_iocore_t    *io = &ip->i_iocore;
893         xfs_fileoff_t   offset_fsb;
894         xfs_filblks_t   count_fsb;
895         xfs_filblks_t   numblks_fsb;
896         xfs_fsblock_t   firstfsb;
897         int             nimaps;
898         xfs_trans_t     *tp;
899         xfs_bmbt_irec_t imap;
900         xfs_bmap_free_t free_list;
901         uint            resblks;
902         int             committed;
903         int             error;
904
905         xfs_iomap_enter_trace(XFS_IOMAP_UNWRITTEN,
906                                 &ip->i_iocore, offset, count);
907
908         offset_fsb = XFS_B_TO_FSBT(mp, offset);
909         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
910         count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
911
912         resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
913
914         do {
915                 /*
916                  * set up a transaction to convert the range of extents
917                  * from unwritten to real. Do allocations in a loop until
918                  * we have covered the range passed in.
919                  */
920
921                 tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
922                 error = xfs_trans_reserve(tp, resblks,
923                                 XFS_WRITE_LOG_RES(mp), 0,
924                                 XFS_TRANS_PERM_LOG_RES,
925                                 XFS_WRITE_LOG_COUNT);
926                 if (error) {
927                         xfs_trans_cancel(tp, 0);
928                         return XFS_ERROR(error);
929                 }
930
931                 xfs_ilock(ip, XFS_ILOCK_EXCL);
932                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
933                 xfs_trans_ihold(tp, ip);
934
935                 /*
936                  * Modify the unwritten extent state of the buffer.
937                  */
938                 XFS_BMAP_INIT(&free_list, &firstfsb);
939                 nimaps = 1;
940                 error = XFS_BMAPI(mp, tp, io, offset_fsb, count_fsb,
941                                   XFS_BMAPI_WRITE|XFS_BMAPI_CONVERT, &firstfsb,
942                                   1, &imap, &nimaps, &free_list, NULL);
943                 if (error)
944                         goto error_on_bmapi_transaction;
945
946                 error = xfs_bmap_finish(&(tp), &(free_list), &committed);
947                 if (error)
948                         goto error_on_bmapi_transaction;
949
950                 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
951                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
952                 if (error)
953                         return XFS_ERROR(error);
954
955                 if (unlikely(!imap.br_startblock &&
956                              !(io->io_flags & XFS_IOCORE_RT)))
957                         return xfs_cmn_err_fsblock_zero(ip, &imap);
958
959                 if ((numblks_fsb = imap.br_blockcount) == 0) {
960                         /*
961                          * The numblks_fsb value should always get
962                          * smaller, otherwise the loop is stuck.
963                          */
964                         ASSERT(imap.br_blockcount);
965                         break;
966                 }
967                 offset_fsb += numblks_fsb;
968                 count_fsb -= numblks_fsb;
969         } while (count_fsb > 0);
970
971         return 0;
972
973 error_on_bmapi_transaction:
974         xfs_bmap_cancel(&free_list);
975         xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT));
976         xfs_iunlock(ip, XFS_ILOCK_EXCL);
977         return XFS_ERROR(error);
978 }