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