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;
 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_extlen_t    extsize,
 294         xfs_fileoff_t   *last_fsb)
 295 {
 296         xfs_fileoff_t   new_last_fsb = 0;
 297         xfs_extlen_t    align;
 298         int             eof, error;
 299
 300         if (XFS_IS_REALTIME_INODE(ip))
 301                 ;
 302         /*
 303          * If mounted with the "-o swalloc" option, roundup the allocation
 304          * request to a stripe width boundary if the file size is >=
 305          * stripe width and we are allocating past the allocation eof.
 306          */
 307         else if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC) &&
 308                 (ip->i_size >= XFS_FSB_TO_B(mp, mp->m_swidth)))
 309                 new_last_fsb = roundup_64(*last_fsb, mp->m_swidth);
 310         /*
 311          * Roundup the allocation request to a stripe unit (m_dalign) boundary
 312          * if the file size is >= stripe unit size, and we are allocating past
 313          * the allocation eof.
 314          */
 315         else if (mp->m_dalign && (ip->i_size >= XFS_FSB_TO_B(mp, mp->m_dalign)))
 316                 new_last_fsb = roundup_64(*last_fsb, mp->m_dalign);
 317
 318         /*
 319          * Always round up the allocation request to an extent boundary
 320          * (when file on a real-time subvolume or has di_extsize hint).
 321          */
 322         if (extsize) {
 323                 if (new_last_fsb)
 324                         align = roundup_64(new_last_fsb, extsize);
 325                 else
 326                         align = extsize;
 327                 new_last_fsb = roundup_64(*last_fsb, align);
 328         }
 329
 330         if (new_last_fsb) {
 331                 error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
 332                 if (error)
 333                         return error;
 334                 if (eof)
 335                         *last_fsb = new_last_fsb;
 336         }
 337         return 0;
 338 }
 339
 340 STATIC int
 341 xfs_cmn_err_fsblock_zero(
 342         xfs_inode_t     *ip,
 343         xfs_bmbt_irec_t *imap)
 344 {
 345         xfs_cmn_err(XFS_PTAG_FSBLOCK_ZERO, CE_ALERT, ip->i_mount,
 346                         "Access to block zero in inode %llu "
 347                         "start_block: %llx start_off: %llx "
 348                         "blkcnt: %llx extent-state: %x\n",
 349                 (unsigned long long)ip->i_ino,
 350                 (unsigned long long)imap->br_startblock,
 351                 (unsigned long long)imap->br_startoff,
 352                 (unsigned long long)imap->br_blockcount,
 353                 imap->br_state);
 354         return EFSCORRUPTED;
 355 }
 356
 357 int
 358 xfs_iomap_write_direct(
 359         xfs_inode_t     *ip,
 360         xfs_off_t       offset,
 361         size_t          count,
 362         int             flags,
 363         xfs_bmbt_irec_t *ret_imap,
 364         int             *nmaps,
 365         int             found)
 366 {
 367         xfs_mount_t     *mp = ip->i_mount;
 368         xfs_fileoff_t   offset_fsb;
 369         xfs_fileoff_t   last_fsb;
 370         xfs_filblks_t   count_fsb, resaligned;
 371         xfs_fsblock_t   firstfsb;
 372         xfs_extlen_t    extsz, temp;
 373         int             nimaps;
 374         int             bmapi_flag;
 375         int             quota_flag;
 376         int             rt;
 377         xfs_trans_t     *tp;
 378         xfs_bmbt_irec_t imap;
 379         xfs_bmap_free_t free_list;
 380         uint            qblocks, resblks, resrtextents;
 381         int             committed;
 382         int             error;
 383
 384         /*
 385          * Make sure that the dquots are there. This doesn't hold
 386          * the ilock across a disk read.
 387          */
 388         error = XFS_QM_DQATTACH(ip->i_mount, ip, XFS_QMOPT_ILOCKED);
 389         if (error)
 390                 return XFS_ERROR(error);
 391
 392         rt = XFS_IS_REALTIME_INODE(ip);
 393         extsz = xfs_get_extsz_hint(ip);
 394
 395         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 396         last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
 397         if ((offset + count) > ip->i_size) {
 398                 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
 399                 if (error)
 400                         goto error_out;
 401         } else {
 402                 if (found && (ret_imap->br_startblock == HOLESTARTBLOCK))
 403                         last_fsb = MIN(last_fsb, (xfs_fileoff_t)
 404                                         ret_imap->br_blockcount +
 405                                         ret_imap->br_startoff);
 406         }
 407         count_fsb = last_fsb - offset_fsb;
 408         ASSERT(count_fsb > 0);
 409
 410         resaligned = count_fsb;
 411         if (unlikely(extsz)) {
 412                 if ((temp = do_mod(offset_fsb, extsz)))
 413                         resaligned += temp;
 414                 if ((temp = do_mod(resaligned, extsz)))
 415                         resaligned += extsz - temp;
 416         }
 417
 418         if (unlikely(rt)) {
 419                 resrtextents = qblocks = resaligned;
 420                 resrtextents /= mp->m_sb.sb_rextsize;
 421                 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
 422                 quota_flag = XFS_QMOPT_RES_RTBLKS;
 423         } else {
 424                 resrtextents = 0;
 425                 resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
 426                 quota_flag = XFS_QMOPT_RES_REGBLKS;
 427         }
 428
 429         /*
 430          * Allocate and setup the transaction
 431          */
 432         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 433         tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
 434         error = xfs_trans_reserve(tp, resblks,
 435                         XFS_WRITE_LOG_RES(mp), resrtextents,
 436                         XFS_TRANS_PERM_LOG_RES,
 437                         XFS_WRITE_LOG_COUNT);
 438         /*
 439          * Check for running out of space, note: need lock to return
 440          */
 441         if (error)
 442                 xfs_trans_cancel(tp, 0);
 443         xfs_ilock(ip, XFS_ILOCK_EXCL);
 444         if (error)
 445                 goto error_out;
 446
 447         error = XFS_TRANS_RESERVE_QUOTA_NBLKS(mp, tp, ip,
 448                                               qblocks, 0, quota_flag);
 449         if (error)
 450                 goto error1;
 451
 452         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 453         xfs_trans_ihold(tp, ip);
 454
 455         bmapi_flag = XFS_BMAPI_WRITE;
 456         if ((flags & BMAPI_DIRECT) && (offset < ip->i_size || extsz))
 457                 bmapi_flag |= XFS_BMAPI_PREALLOC;
 458
 459         /*
 460          * Issue the xfs_bmapi() call to allocate the blocks
 461          */
 462         xfs_bmap_init(&free_list, &firstfsb);
 463         nimaps = 1;
 464         error = xfs_bmapi(tp, ip, offset_fsb, count_fsb, bmapi_flag,
 465                 &firstfsb, 0, &imap, &nimaps, &free_list, NULL);
 466         if (error)
 467                 goto error0;
 468
 469         /*
 470          * Complete the transaction
 471          */
 472         error = xfs_bmap_finish(&tp, &free_list, &committed);
 473         if (error)
 474                 goto error0;
 475         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 476         if (error)
 477                 goto error_out;
 478
 479         /*
 480          * Copy any maps to caller's array and return any error.
 481          */
 482         if (nimaps == 0) {
 483                 error = ENOSPC;
 484                 goto error_out;
 485         }
 486
 487         if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip))) {
 488                 error = xfs_cmn_err_fsblock_zero(ip, &imap);
 489                 goto error_out;
 490         }
 491
 492         *ret_imap = imap;
 493         *nmaps = 1;
 494         return 0;
 495
 496 error0: /* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
 497         xfs_bmap_cancel(&free_list);
 498         XFS_TRANS_UNRESERVE_QUOTA_NBLKS(mp, tp, ip, qblocks, 0, quota_flag);
 499
 500 error1: /* Just cancel transaction */
 501         xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
 502         *nmaps = 0;     /* nothing set-up here */
 503
 504 error_out:
 505         return XFS_ERROR(error);
 506 }
 507
 508 /*
 509  * If the caller is doing a write at the end of the file, then extend the
 510  * allocation out to the file system's write iosize.  We clean up any extra
 511  * space left over when the file is closed in xfs_inactive().
 512  */
 513 STATIC int
 514 xfs_iomap_eof_want_preallocate(
 515         xfs_mount_t     *mp,
 516         xfs_inode_t     *ip,
 517         xfs_off_t       offset,
 518         size_t          count,
 519         int             ioflag,
 520         xfs_bmbt_irec_t *imap,
 521         int             nimaps,
 522         int             *prealloc)
 523 {
 524         xfs_fileoff_t   start_fsb;
 525         xfs_filblks_t   count_fsb;
 526         xfs_fsblock_t   firstblock;
 527         int             n, error, imaps;
 528
 529         *prealloc = 0;
 530         if ((offset + count) <= ip->i_size)
 531                 return 0;
 532
 533         /*
 534          * If there are any real blocks past eof, then don't
 535          * do any speculative allocation.
 536          */
 537         start_fsb = XFS_B_TO_FSBT(mp, ((xfs_ufsize_t)(offset + count - 1)));
 538         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
 539         while (count_fsb > 0) {
 540                 imaps = nimaps;
 541                 firstblock = NULLFSBLOCK;
 542                 error = xfs_bmapi(NULL, ip, start_fsb, count_fsb, 0,
 543                                   &firstblock, 0, imap, &imaps, NULL, NULL);
 544                 if (error)
 545                         return error;
 546                 for (n = 0; n < imaps; n++) {
 547                         if ((imap[n].br_startblock != HOLESTARTBLOCK) &&
 548                             (imap[n].br_startblock != DELAYSTARTBLOCK))
 549                                 return 0;
 550                         start_fsb += imap[n].br_blockcount;
 551                         count_fsb -= imap[n].br_blockcount;
 552                 }
 553         }
 554         *prealloc = 1;
 555         return 0;
 556 }
 557
 558 int
 559 xfs_iomap_write_delay(
 560         xfs_inode_t     *ip,
 561         xfs_off_t       offset,
 562         size_t          count,
 563         int             ioflag,
 564         xfs_bmbt_irec_t *ret_imap,
 565         int             *nmaps)
 566 {
 567         xfs_mount_t     *mp = ip->i_mount;
 568         xfs_fileoff_t   offset_fsb;
 569         xfs_fileoff_t   last_fsb;
 570         xfs_off_t       aligned_offset;
 571         xfs_fileoff_t   ioalign;
 572         xfs_fsblock_t   firstblock;
 573         xfs_extlen_t    extsz;
 574         int             nimaps;
 575         xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];
 576         int             prealloc, flushed = 0;
 577         int             error;
 578
 579         ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
 580
 581         /*
 582          * Make sure that the dquots are there. This doesn't hold
 583          * the ilock across a disk read.
 584          */
 585         error = XFS_QM_DQATTACH(mp, ip, XFS_QMOPT_ILOCKED);
 586         if (error)
 587                 return XFS_ERROR(error);
 588
 589         extsz = xfs_get_extsz_hint(ip);
 590         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 591
 592         error = xfs_iomap_eof_want_preallocate(mp, ip, offset, count,
 593                                 ioflag, imap, XFS_WRITE_IMAPS, &prealloc);
 594         if (error)
 595                 return error;
 596
 597 retry:
 598         if (prealloc) {
 599                 aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1));
 600                 ioalign = XFS_B_TO_FSBT(mp, aligned_offset);
 601                 last_fsb = ioalign + mp->m_writeio_blocks;
 602         } else {
 603                 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
 604         }
 605
 606         if (prealloc || extsz) {
 607                 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
 608                 if (error)
 609                         return error;
 610         }
 611
 612         nimaps = XFS_WRITE_IMAPS;
 613         firstblock = NULLFSBLOCK;
 614         error = xfs_bmapi(NULL, ip, offset_fsb,
 615                           (xfs_filblks_t)(last_fsb - offset_fsb),
 616                           XFS_BMAPI_DELAY | XFS_BMAPI_WRITE |
 617                           XFS_BMAPI_ENTIRE, &firstblock, 1, imap,
 618                           &nimaps, NULL, NULL);
 619         if (error && (error != ENOSPC))
 620                 return XFS_ERROR(error);
 621
 622         /*
 623          * If bmapi returned us nothing, and if we didn't get back EDQUOT,
 624          * then we must have run out of space - flush all other inodes with
 625          * delalloc blocks and retry without EOF preallocation.
 626          */
 627         if (nimaps == 0) {
 628                 xfs_iomap_enter_trace(XFS_IOMAP_WRITE_NOSPACE,
 629                                         ip, offset, count);
 630                 if (flushed)
 631                         return XFS_ERROR(ENOSPC);
 632
 633                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 634                 xfs_flush_inodes(ip);
 635                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 636
 637                 flushed = 1;
 638                 error = 0;
 639                 prealloc = 0;
 640                 goto retry;
 641         }
 642
 643         if (!(imap[0].br_startblock || XFS_IS_REALTIME_INODE(ip)))
 644                 return xfs_cmn_err_fsblock_zero(ip, &imap[0]);
 645
 646         *ret_imap = imap[0];
 647         *nmaps = 1;
 648
 649         return 0;
 650 }
 651
 652 /*
 653  * Pass in a delayed allocate extent, convert it to real extents;
 654  * return to the caller the extent we create which maps on top of
 655  * the originating callers request.
 656  *
 657  * Called without a lock on the inode.
 658  *
 659  * We no longer bother to look at the incoming map - all we have to
 660  * guarantee is that whatever we allocate fills the required range.
 661  */
 662 int
 663 xfs_iomap_write_allocate(
 664         xfs_inode_t     *ip,
 665         xfs_off_t       offset,
 666         size_t          count,
 667         xfs_bmbt_irec_t *map,
 668         int             *retmap)
 669 {
 670         xfs_mount_t     *mp = ip->i_mount;
 671         xfs_fileoff_t   offset_fsb, last_block;
 672         xfs_fileoff_t   end_fsb, map_start_fsb;
 673         xfs_fsblock_t   first_block;
 674         xfs_bmap_free_t free_list;
 675         xfs_filblks_t   count_fsb;
 676         xfs_bmbt_irec_t imap;
 677         xfs_trans_t     *tp;
 678         int             nimaps, committed;
 679         int             error = 0;
 680         int             nres;
 681
 682         *retmap = 0;
 683
 684         /*
 685          * Make sure that the dquots are there.
 686          */
 687         if ((error = XFS_QM_DQATTACH(mp, ip, 0)))
 688                 return XFS_ERROR(error);
 689
 690         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 691         count_fsb = map->br_blockcount;
 692         map_start_fsb = map->br_startoff;
 693
 694         XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
 695
 696         while (count_fsb != 0) {
 697                 /*
 698                  * Set up a transaction with which to allocate the
 699                  * backing store for the file.  Do allocations in a
 700                  * loop until we get some space in the range we are
 701                  * interested in.  The other space that might be allocated
 702                  * is in the delayed allocation extent on which we sit
 703                  * but before our buffer starts.
 704                  */
 705
 706                 nimaps = 0;
 707                 while (nimaps == 0) {
 708                         tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
 709                         tp->t_flags |= XFS_TRANS_RESERVE;
 710                         nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
 711                         error = xfs_trans_reserve(tp, nres,
 712                                         XFS_WRITE_LOG_RES(mp),
 713                                         0, XFS_TRANS_PERM_LOG_RES,
 714                                         XFS_WRITE_LOG_COUNT);
 715                         if (error) {
 716                                 xfs_trans_cancel(tp, 0);
 717                                 return XFS_ERROR(error);
 718                         }
 719                         xfs_ilock(ip, XFS_ILOCK_EXCL);
 720                         xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 721                         xfs_trans_ihold(tp, ip);
 722
 723                         xfs_bmap_init(&free_list, &first_block);
 724
 725                         /*
 726                          * it is possible that the extents have changed since
 727                          * we did the read call as we dropped the ilock for a
 728                          * while. We have to be careful about truncates or hole
 729                          * punchs here - we are not allowed to allocate
 730                          * non-delalloc blocks here.
 731                          *
 732                          * The only protection against truncation is the pages
 733                          * for the range we are being asked to convert are
 734                          * locked and hence a truncate will block on them
 735                          * first.
 736                          *
 737                          * As a result, if we go beyond the range we really
 738                          * need and hit an delalloc extent boundary followed by
 739                          * a hole while we have excess blocks in the map, we
 740                          * will fill the hole incorrectly and overrun the
 741                          * transaction reservation.
 742                          *
 743                          * Using a single map prevents this as we are forced to
 744                          * check each map we look for overlap with the desired
 745                          * range and abort as soon as we find it. Also, given
 746                          * that we only return a single map, having one beyond
 747                          * what we can return is probably a bit silly.
 748                          *
 749                          * We also need to check that we don't go beyond EOF;
 750                          * this is a truncate optimisation as a truncate sets
 751                          * the new file size before block on the pages we
 752                          * currently have locked under writeback. Because they
 753                          * are about to be tossed, we don't need to write them
 754                          * back....
 755                          */
 756                         nimaps = 1;
 757                         end_fsb = XFS_B_TO_FSB(mp, ip->i_size);
 758                         error = xfs_bmap_last_offset(NULL, ip, &last_block,
 759                                                         XFS_DATA_FORK);
 760                         if (error)
 761                                 goto trans_cancel;
 762
 763                         last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
 764                         if ((map_start_fsb + count_fsb) > last_block) {
 765                                 count_fsb = last_block - map_start_fsb;
 766                                 if (count_fsb == 0) {
 767                                         error = EAGAIN;
 768                                         goto trans_cancel;
 769                                 }
 770                         }
 771
 772                         /* Go get the actual blocks */
 773                         error = xfs_bmapi(tp, ip, map_start_fsb, count_fsb,
 774                                         XFS_BMAPI_WRITE, &first_block, 1,
 775                                         &imap, &nimaps, &free_list, NULL);
 776                         if (error)
 777                                 goto trans_cancel;
 778
 779                         error = xfs_bmap_finish(&tp, &free_list, &committed);
 780                         if (error)
 781                                 goto trans_cancel;
 782
 783                         error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 784                         if (error)
 785                                 goto error0;
 786
 787                         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 788                 }
 789
 790                 /*
 791                  * See if we were able to allocate an extent that
 792                  * covers at least part of the callers request
 793                  */
 794                 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
 795                         return xfs_cmn_err_fsblock_zero(ip, &imap);
 796
 797                 if ((offset_fsb >= imap.br_startoff) &&
 798                     (offset_fsb < (imap.br_startoff +
 799                                    imap.br_blockcount))) {
 800                         *map = imap;
 801                         *retmap = 1;
 802                         XFS_STATS_INC(xs_xstrat_quick);
 803                         return 0;
 804                 }
 805
 806                 /*
 807                  * So far we have not mapped the requested part of the
 808                  * file, just surrounding data, try again.
 809                  */
 810                 count_fsb -= imap.br_blockcount;
 811                 map_start_fsb = imap.br_startoff + imap.br_blockcount;
 812         }
 813
 814 trans_cancel:
 815         xfs_bmap_cancel(&free_list);
 816         xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
 817 error0:
 818         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 819         return XFS_ERROR(error);
 820 }
 821
 822 int
 823 xfs_iomap_write_unwritten(
 824         xfs_inode_t     *ip,
 825         xfs_off_t       offset,
 826         size_t          count)
 827 {
 828         xfs_mount_t     *mp = ip->i_mount;
 829         xfs_fileoff_t   offset_fsb;
 830         xfs_filblks_t   count_fsb;
 831         xfs_filblks_t   numblks_fsb;
 832         xfs_fsblock_t   firstfsb;
 833         int             nimaps;
 834         xfs_trans_t     *tp;
 835         xfs_bmbt_irec_t imap;
 836         xfs_bmap_free_t free_list;
 837         uint            resblks;
 838         int             committed;
 839         int             error;
 840
 841         xfs_iomap_enter_trace(XFS_IOMAP_UNWRITTEN, ip, offset, count);
 842
 843         offset_fsb = XFS_B_TO_FSBT(mp, offset);
 844         count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
 845         count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
 846
 847         /*
 848          * Reserve enough blocks in this transaction for two complete extent
 849          * btree splits.  We may be converting the middle part of an unwritten
 850          * extent and in this case we will insert two new extents in the btree
 851          * each of which could cause a full split.
 852          *
 853          * This reservation amount will be used in the first call to
 854          * xfs_bmbt_split() to select an AG with enough space to satisfy the
 855          * rest of the operation.
 856          */
 857         resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
 858
 859         do {
 860                 /*
 861                  * set up a transaction to convert the range of extents
 862                  * from unwritten to real. Do allocations in a loop until
 863                  * we have covered the range passed in.
 864                  */
 865                 tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
 866                 tp->t_flags |= XFS_TRANS_RESERVE;
 867                 error = xfs_trans_reserve(tp, resblks,
 868                                 XFS_WRITE_LOG_RES(mp), 0,
 869                                 XFS_TRANS_PERM_LOG_RES,
 870                                 XFS_WRITE_LOG_COUNT);
 871                 if (error) {
 872                         xfs_trans_cancel(tp, 0);
 873                         return XFS_ERROR(error);
 874                 }
 875
 876                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 877                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
 878                 xfs_trans_ihold(tp, ip);
 879
 880                 /*
 881                  * Modify the unwritten extent state of the buffer.
 882                  */
 883                 xfs_bmap_init(&free_list, &firstfsb);
 884                 nimaps = 1;
 885                 error = xfs_bmapi(tp, ip, offset_fsb, count_fsb,
 886                                   XFS_BMAPI_WRITE|XFS_BMAPI_CONVERT, &firstfsb,
 887                                   1, &imap, &nimaps, &free_list, NULL);
 888                 if (error)
 889                         goto error_on_bmapi_transaction;
 890
 891                 error = xfs_bmap_finish(&(tp), &(free_list), &committed);
 892                 if (error)
 893                         goto error_on_bmapi_transaction;
 894
 895                 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
 896                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 897                 if (error)
 898                         return XFS_ERROR(error);
 899
 900                 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
 901                         return xfs_cmn_err_fsblock_zero(ip, &imap);
 902
 903                 if ((numblks_fsb = imap.br_blockcount) == 0) {
 904                         /*
 905                          * The numblks_fsb value should always get
 906                          * smaller, otherwise the loop is stuck.
 907                          */
 908                         ASSERT(imap.br_blockcount);
 909                         break;
 910                 }
 911                 offset_fsb += numblks_fsb;
 912                 count_fsb -= numblks_fsb;
 913         } while (count_fsb > 0);
 914
 915         return 0;
 916
 917 error_on_bmapi_transaction:
 918         xfs_bmap_cancel(&free_list);
 919         xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT));
 920         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 921         return XFS_ERROR(error);
 922 }