git.oblomov.eu Git - 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|XFS_EXTSIZE_WR;
 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|XFS_EXTSIZE_RD;
 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(ismrlocked(&ip->i_lock, MR_UPDATE) != 0);
 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                         xfs_bmap_last_offset(NULL, ip, &last_block,
 806                                 XFS_DATA_FORK);
 807                         last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
 808                         if ((map_start_fsb + count_fsb) > last_block) {
 809                                 count_fsb = last_block - map_start_fsb;
 810                                 if (count_fsb == 0) {
 811                                         error = EAGAIN;
 812                                         goto trans_cancel;
 813                                 }
 814                         }
 815
 816                         /* Go get the actual blocks */
 817                         error = xfs_bmapi(tp, ip, map_start_fsb, count_fsb,
 818                                         XFS_BMAPI_WRITE, &first_block, 1,
 819                                         &imap, &nimaps, &free_list, NULL);
 820                         if (error)
 821                                 goto trans_cancel;
 822
 823                         error = xfs_bmap_finish(&tp, &free_list, &committed);
 824                         if (error)
 825                                 goto trans_cancel;
 826
 827                         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 828                         if (error)
 829                                 goto error0;
 830
 831                         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 832                 }
 833
 834                 /*
 835                  * See if we were able to allocate an extent that
 836                  * covers at least part of the callers request
 837                  */
 838                 if (unlikely(!imap.br_startblock &&
 839                              XFS_IS_REALTIME_INODE(ip)))
 840                         return xfs_cmn_err_fsblock_zero(ip, &imap);
 841                 if ((offset_fsb >= imap.br_startoff) &&
 842                     (offset_fsb < (imap.br_startoff +
 843                                    imap.br_blockcount))) {
 844                         *map = imap;
 845                         *retmap = 1;
 846                         XFS_STATS_INC(xs_xstrat_quick);
 847                         return 0;
 848                 }
 849
 850                 /*
 851                  * So far we have not mapped the requested part of the
 852                  * file, just surrounding data, try again.
 853                  */
 854                 count_fsb -= imap.br_blockcount;
 855                 map_start_fsb = imap.br_startoff + imap.br_blockcount;
 856         }
 857
 858 trans_cancel:
 859         xfs_bmap_cancel(&free_list);
 860         xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
 861 error0:
 862         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 863         return XFS_ERROR(error);
 864 }
 865
 866 int
 867 xfs_iomap_write_unwritten(
 868         xfs_inode_t     *ip,
 869         xfs_off_t       offset,
 870         size_t          count)
 871 {
 872         xfs_mount_t     *mp = ip->i_mount;
 873         xfs_fileoff_t   offset_fsb;
 874         xfs_filblks_t   count_fsb;
 875         xfs_filblks_t   numblks_fsb;
 876         xfs_fsblock_t   firstfsb;
 877         int             nimaps;
 878         xfs_trans_t     *tp;
 879         xfs_bmbt_irec_t imap;
 880         xfs_bmap_free_t free_list;
 881         uint            resblks;
 882         int             committed;
 883         int             error;
 884
 885         xfs_iomap_enter_trace(XFS_IOMAP_UNWRITTEN, ip, offset, count);
 886
 887         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 888         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
 889         count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
 890
 891         resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
 892
 893         do {
 894                 /*
 895                  * set up a transaction to convert the range of extents
 896                  * from unwritten to real. Do allocations in a loop until
 897                  * we have covered the range passed in.
 898                  */
 899                 tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
 900                 tp->t_flags |= XFS_TRANS_RESERVE;
 901                 error = xfs_trans_reserve(tp, resblks,
 902                                 XFS_WRITE_LOG_RES(mp), 0,
 903                                 XFS_TRANS_PERM_LOG_RES,
 904                                 XFS_WRITE_LOG_COUNT);
 905                 if (error) {
 906                         xfs_trans_cancel(tp, 0);
 907                         return XFS_ERROR(error);
 908                 }
 909
 910                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 911                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 912                 xfs_trans_ihold(tp, ip);
 913
 914                 /*
 915                  * Modify the unwritten extent state of the buffer.
 916                  */
 917                 XFS_BMAP_INIT(&free_list, &firstfsb);
 918                 nimaps = 1;
 919                 error = xfs_bmapi(tp, ip, offset_fsb, count_fsb,
 920                                   XFS_BMAPI_WRITE|XFS_BMAPI_CONVERT, &firstfsb,
 921                                   1, &imap, &nimaps, &free_list, NULL);
 922                 if (error)
 923                         goto error_on_bmapi_transaction;
 924
 925                 error = xfs_bmap_finish(&(tp), &(free_list), &committed);
 926                 if (error)
 927                         goto error_on_bmapi_transaction;
 928
 929                 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 930                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 931                 if (error)
 932                         return XFS_ERROR(error);
 933
 934                 if (unlikely(!imap.br_startblock &&
 935                              !(XFS_IS_REALTIME_INODE(ip))))
 936                         return xfs_cmn_err_fsblock_zero(ip, &imap);
 937
 938                 if ((numblks_fsb = imap.br_blockcount) == 0) {
 939                         /*
 940                          * The numblks_fsb value should always get
 941                          * smaller, otherwise the loop is stuck.
 942                          */
 943                         ASSERT(imap.br_blockcount);
 944                         break;
 945                 }
 946                 offset_fsb += numblks_fsb;
 947                 count_fsb -= numblks_fsb;
 948         } while (count_fsb > 0);
 949
 950         return 0;
 951
 952 error_on_bmapi_transaction:
 953         xfs_bmap_cancel(&free_list);
 954         xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT));
 955         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 956         return XFS_ERROR(error);
 957 }