SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip))) {
 527                 error = xfs_cmn_err_fsblock_zero(ip, &imap);
 528                 goto error_out;
 529         }
 530
 531         *ret_imap = imap;
 532         *nmaps = 1;
 533         return 0;
 534
 535 error0: /* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
 536         xfs_bmap_cancel(&free_list);
 537         XFS_TRANS_UNRESERVE_QUOTA_NBLKS(mp, tp, ip, qblocks, 0, quota_flag);
 538
 539 error1: /* Just cancel transaction */
 540         xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
 541         *nmaps = 0;     /* nothing set-up here */
 542
 543 error_out:
 544         return XFS_ERROR(error);
 545 }
 546
 547 /*
 548  * If the caller is doing a write at the end of the file,
 549  * then extend the allocation out to the file system's write
 550  * iosize.  We clean up any extra space left over when the
 551  * file is closed in xfs_inactive().
 552  *
 553  * For sync writes, we are flushing delayed allocate space to
 554  * try to make additional space available for allocation near
 555  * the filesystem full boundary - preallocation hurts in that
 556  * situation, of course.
 557  */
 558 STATIC int
 559 xfs_iomap_eof_want_preallocate(
 560         xfs_mount_t     *mp,
 561         xfs_inode_t     *ip,
 562         xfs_fsize_t     isize,
 563         xfs_off_t       offset,
 564         size_t          count,
 565         int             ioflag,
 566         xfs_bmbt_irec_t *imap,
 567         int             nimaps,
 568         int             *prealloc)
 569 {
 570         xfs_fileoff_t   start_fsb;
 571         xfs_filblks_t   count_fsb;
 572         xfs_fsblock_t   firstblock;
 573         int             n, error, imaps;
 574
 575         *prealloc = 0;
 576         if ((ioflag & BMAPI_SYNC) || (offset + count) <= isize)
 577                 return 0;
 578
 579         /*
 580          * If there are any real blocks past eof, then don't
 581          * do any speculative allocation.
 582          */
 583         start_fsb = XFS_B_TO_FSBT(mp, ((xfs_ufsize_t)(offset + count - 1)));
 584         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
 585         while (count_fsb > 0) {
 586                 imaps = nimaps;
 587                 firstblock = NULLFSBLOCK;
 588                 error = xfs_bmapi(NULL, ip, start_fsb, count_fsb, 0,
 589                                   &firstblock, 0, imap, &imaps, NULL, NULL);
 590                 if (error)
 591                         return error;
 592                 for (n = 0; n < imaps; n++) {
 593                         if ((imap[n].br_startblock != HOLESTARTBLOCK) &&
 594                             (imap[n].br_startblock != DELAYSTARTBLOCK))
 595                                 return 0;
 596                         start_fsb += imap[n].br_blockcount;
 597                         count_fsb -= imap[n].br_blockcount;
 598                 }
 599         }
 600         *prealloc = 1;
 601         return 0;
 602 }
 603
 604 int
 605 xfs_iomap_write_delay(
 606         xfs_inode_t     *ip,
 607         xfs_off_t       offset,
 608         size_t          count,
 609         int             ioflag,
 610         xfs_bmbt_irec_t *ret_imap,
 611         int             *nmaps)
 612 {
 613         xfs_mount_t     *mp = ip->i_mount;
 614         xfs_fileoff_t   offset_fsb;
 615         xfs_fileoff_t   last_fsb;
 616         xfs_off_t       aligned_offset;
 617         xfs_fileoff_t   ioalign;
 618         xfs_fsblock_t   firstblock;
 619         xfs_extlen_t    extsz;
 620         xfs_fsize_t     isize;
 621         int             nimaps;
 622         xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];
 623         int             prealloc, fsynced = 0;
 624         int             error;
 625
 626         ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 627
 628         /*
 629          * Make sure that the dquots are there. This doesn't hold
 630          * the ilock across a disk read.
 631          */
 632         error = XFS_QM_DQATTACH(mp, ip, XFS_QMOPT_ILOCKED);
 633         if (error)
 634                 return XFS_ERROR(error);
 635
 636         extsz = xfs_get_extsz_hint(ip);
 637         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 638
 639 retry:
 640         isize = ip->i_size;
 641         if (ip->i_new_size > isize)
 642                 isize = ip->i_new_size;
 643
 644         error = xfs_iomap_eof_want_preallocate(mp, ip, isize, offset, count,
 645                                 ioflag, imap, XFS_WRITE_IMAPS, &prealloc);
 646         if (error)
 647                 return error;
 648
 649         if (prealloc) {
 650                 aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1));
 651                 ioalign = XFS_B_TO_FSBT(mp, aligned_offset);
 652                 last_fsb = ioalign + mp->m_writeio_blocks;
 653         } else {
 654                 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
 655         }
 656
 657         if (prealloc || extsz) {
 658                 error = xfs_iomap_eof_align_last_fsb(mp, ip, isize, extsz,
 659                                                         &last_fsb);
 660                 if (error)
 661                         return error;
 662         }
 663
 664         nimaps = XFS_WRITE_IMAPS;
 665         firstblock = NULLFSBLOCK;
 666         error = xfs_bmapi(NULL, ip, offset_fsb,
 667                           (xfs_filblks_t)(last_fsb - offset_fsb),
 668                           XFS_BMAPI_DELAY | XFS_BMAPI_WRITE |
 669                           XFS_BMAPI_ENTIRE, &firstblock, 1, imap,
 670                           &nimaps, NULL, NULL);
 671         if (error && (error != ENOSPC))
 672                 return XFS_ERROR(error);
 673
 674         /*
 675          * If bmapi returned us nothing, and if we didn't get back EDQUOT,
 676          * then we must have run out of space - flush delalloc, and retry..
 677          */
 678         if (nimaps == 0) {
 679                 xfs_iomap_enter_trace(XFS_IOMAP_WRITE_NOSPACE,
 680                                         ip, offset, count);
 681                 if (xfs_flush_space(ip, &fsynced, &ioflag))
 682                         return XFS_ERROR(ENOSPC);
 683
 684                 error = 0;
 685                 goto retry;
 686         }
 687
 688         if (!(imap[0].br_startblock || XFS_IS_REALTIME_INODE(ip)))
 689                 return xfs_cmn_err_fsblock_zero(ip, &imap[0]);
 690
 691         *ret_imap = imap[0];
 692         *nmaps = 1;
 693
 694         return 0;
 695 }
 696
 697 /*
 698  * Pass in a delayed allocate extent, convert it to real extents;
 699  * return to the caller the extent we create which maps on top of
 700  * the originating callers request.
 701  *
 702  * Called without a lock on the inode.
 703  *
 704  * We no longer bother to look at the incoming map - all we have to
 705  * guarantee is that whatever we allocate fills the required range.
 706  */
 707 int
 708 xfs_iomap_write_allocate(
 709         xfs_inode_t     *ip,
 710         xfs_off_t       offset,
 711         size_t          count,
 712         xfs_bmbt_irec_t *map,
 713         int             *retmap)
 714 {
 715         xfs_mount_t     *mp = ip->i_mount;
 716         xfs_fileoff_t   offset_fsb, last_block;
 717         xfs_fileoff_t   end_fsb, map_start_fsb;
 718         xfs_fsblock_t   first_block;
 719         xfs_bmap_free_t free_list;
 720         xfs_filblks_t   count_fsb;
 721         xfs_bmbt_irec_t imap;
 722         xfs_trans_t     *tp;
 723         int             nimaps, committed;
 724         int             error = 0;
 725         int             nres;
 726
 727         *retmap = 0;
 728
 729         /*
 730          * Make sure that the dquots are there.
 731          */
 732         if ((error = XFS_QM_DQATTACH(mp, ip, 0)))
 733                 return XFS_ERROR(error);
 734
 735         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 736         count_fsb = map->br_blockcount;
 737         map_start_fsb = map->br_startoff;
 738
 739         XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
 740
 741         while (count_fsb != 0) {
 742                 /*
 743                  * Set up a transaction with which to allocate the
 744                  * backing store for the file.  Do allocations in a
 745                  * loop until we get some space in the range we are
 746                  * interested in.  The other space that might be allocated
 747                  * is in the delayed allocation extent on which we sit
 748                  * but before our buffer starts.
 749                  */
 750
 751                 nimaps = 0;
 752                 while (nimaps == 0) {
 753                         tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
 754                         tp->t_flags |= XFS_TRANS_RESERVE;
 755                         nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
 756                         error = xfs_trans_reserve(tp, nres,
 757                                         XFS_WRITE_LOG_RES(mp),
 758                                         0, XFS_TRANS_PERM_LOG_RES,
 759                                         XFS_WRITE_LOG_COUNT);
 760                         if (error) {
 761                                 xfs_trans_cancel(tp, 0);
 762                                 return XFS_ERROR(error);
 763                         }
 764                         xfs_ilock(ip, XFS_ILOCK_EXCL);
 765                         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 766                         xfs_trans_ihold(tp, ip);
 767
 768                         XFS_BMAP_INIT(&free_list, &first_block);
 769
 770                         /*
 771                          * it is possible that the extents have changed since
 772                          * we did the read call as we dropped the ilock for a
 773                          * while. We have to be careful about truncates or hole
 774                          * punchs here - we are not allowed to allocate
 775                          * non-delalloc blocks here.
 776                          *
 777                          * The only protection against truncation is the pages
 778                          * for the range we are being asked to convert are
 779                          * locked and hence a truncate will block on them
 780                          * first.
 781                          *
 782                          * As a result, if we go beyond the range we really
 783                          * need and hit an delalloc extent boundary followed by
 784                          * a hole while we have excess blocks in the map, we
 785                          * will fill the hole incorrectly and overrun the
 786                          * transaction reservation.
 787                          *
 788                          * Using a single map prevents this as we are forced to
 789                          * check each map we look for overlap with the desired
 790                          * range and abort as soon as we find it. Also, given
 791                          * that we only return a single map, having one beyond
 792                          * what we can return is probably a bit silly.
 793                          *
 794                          * We also need to check that we don't go beyond EOF;
 795                          * this is a truncate optimisation as a truncate sets
 796                          * the new file size before block on the pages we
 797                          * currently have locked under writeback. Because they
 798                          * are about to be tossed, we don't need to write them
 799                          * back....
 800                          */
 801                         nimaps = 1;
 802                         end_fsb = XFS_B_TO_FSB(mp, ip->i_size);
 803                         error = xfs_bmap_last_offset(NULL, ip, &last_block,
 804                                                         XFS_DATA_FORK);
 805                         if (error)
 806                                 goto trans_cancel;
 807
 808                         last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
 809                         if ((map_start_fsb + count_fsb) > last_block) {
 810                                 count_fsb = last_block - map_start_fsb;
 811                                 if (count_fsb == 0) {
 812                                         error = EAGAIN;
 813                                         goto trans_cancel;
 814                                 }
 815                         }
 816
 817                         /* Go get the actual blocks */
 818                         error = xfs_bmapi(tp, ip, map_start_fsb, count_fsb,
 819                                         XFS_BMAPI_WRITE, &first_block, 1,
 820                                         &imap, &nimaps, &free_list, NULL);
 821                         if (error)
 822                                 goto trans_cancel;
 823
 824                         error = xfs_bmap_finish(&tp, &free_list, &committed);
 825                         if (error)
 826                                 goto trans_cancel;
 827
 828                         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 829                         if (error)
 830                                 goto error0;
 831
 832                         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 833                 }
 834
 835                 /*
 836                  * See if we were able to allocate an extent that
 837                  * covers at least part of the callers request
 838                  */
 839                 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
 840                         return xfs_cmn_err_fsblock_zero(ip, &imap);
 841
 842                 if ((offset_fsb >= imap.br_startoff) &&
 843                     (offset_fsb < (imap.br_startoff +
 844                                    imap.br_blockcount))) {
 845                         *map = imap;
 846                         *retmap = 1;
 847                         XFS_STATS_INC(xs_xstrat_quick);
 848                         return 0;
 849                 }
 850
 851                 /*
 852                  * So far we have not mapped the requested part of the
 853                  * file, just surrounding data, try again.
 854                  */
 855                 count_fsb -= imap.br_blockcount;
 856                 map_start_fsb = imap.br_startoff + imap.br_blockcount;
 857         }
 858
 859 trans_cancel:
 860         xfs_bmap_cancel(&free_list);
 861         xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
 862 error0:
 863         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 864         return XFS_ERROR(error);
 865 }
 866
 867 int
 868 xfs_iomap_write_unwritten(
 869         xfs_inode_t     *ip,
 870         xfs_off_t       offset,
 871         size_t          count)
 872 {
 873         xfs_mount_t     *mp = ip->i_mount;
 874         xfs_fileoff_t   offset_fsb;
 875         xfs_filblks_t   count_fsb;
 876         xfs_filblks_t   numblks_fsb;
 877         xfs_fsblock_t   firstfsb;
 878         int             nimaps;
 879         xfs_trans_t     *tp;
 880         xfs_bmbt_irec_t imap;
 881         xfs_bmap_free_t free_list;
 882         uint            resblks;
 883         int             committed;
 884         int             error;
 885
 886         xfs_iomap_enter_trace(XFS_IOMAP_UNWRITTEN, ip, offset, count);
 887
 888         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 889         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
 890         count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
 891
 892         /*
 893          * Reserve enough blocks in this transaction for two complete extent
 894          * btree splits.  We may be converting the middle part of an unwritten
 895          * extent and in this case we will insert two new extents in the btree
 896          * each of which could cause a full split.
 897          *
 898          * This reservation amount will be used in the first call to
 899          * xfs_bmbt_split() to select an AG with enough space to satisfy the
 900          * rest of the operation.
 901          */
 902         resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
 903
 904         do {
 905                 /*
 906                  * set up a transaction to convert the range of extents
 907                  * from unwritten to real. Do allocations in a loop until
 908                  * we have covered the range passed in.
 909                  */
 910                 tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
 911                 tp->t_flags |= XFS_TRANS_RESERVE;
 912                 error = xfs_trans_reserve(tp, resblks,
 913                                 XFS_WRITE_LOG_RES(mp), 0,
 914                                 XFS_TRANS_PERM_LOG_RES,
 915                                 XFS_WRITE_LOG_COUNT);
 916                 if (error) {
 917                         xfs_trans_cancel(tp, 0);
 918                         return XFS_ERROR(error);
 919                 }
 920
 921                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 922                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 923                 xfs_trans_ihold(tp, ip);
 924
 925                 /*
 926                  * Modify the unwritten extent state of the buffer.
 927                  */
 928                 XFS_BMAP_INIT(&free_list, &firstfsb);
 929                 nimaps = 1;
 930                 error = xfs_bmapi(tp, ip, offset_fsb, count_fsb,
 931                                   XFS_BMAPI_WRITE|XFS_BMAPI_CONVERT, &firstfsb,
 932                                   1, &imap, &nimaps, &free_list, NULL);
 933                 if (error)
 934                         goto error_on_bmapi_transaction;
 935
 936                 error = xfs_bmap_finish(&(tp), &(free_list), &committed);
 937                 if (error)
 938                         goto error_on_bmapi_transaction;
 939
 940                 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 941                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 942                 if (error)
 943                         return XFS_ERROR(error);
 944
 945                 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
 946                         return xfs_cmn_err_fsblock_zero(ip, &imap);
 947
 948                 if ((numblks_fsb = imap.br_blockcount) == 0) {
 949                         /*
 950                          * The numblks_fsb value should always get
 951                          * smaller, otherwise the loop is stuck.
 952                          */
 953                         ASSERT(imap.br_blockcount);
 954                         break;
 955                 }
 956                 offset_fsb += numblks_fsb;
 957                 count_fsb -= numblks_fsb;
 958         } while (count_fsb > 0);
 959
 960         return 0;
 961
 962 error_on_bmapi_transaction:
 963         xfs_bmap_cancel(&free_list);
 964         xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT));
 965         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 966         return XFS_ERROR(error);
 967 }