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