root/fs/xfs/xfs_bmap_util.c

DEFINITIONS

1. xfs_fsb_to_db
2. xfs_zero_extent
3. xfs_bmap_rtalloc
4. xfs_bmap_eof
5. xfs_bmap_count_leaves
6. xfs_bmap_disk_count_leaves
7. xfs_bmap_count_tree
8. xfs_bmap_count_blocks
9. xfs_getbmap_report_one
10. xfs_getbmap_report_hole
11. xfs_getbmap_full
12. xfs_getbmap_next_rec
13. xfs_getbmap
14. xfs_bmap_punch_delalloc_range
15. xfs_can_free_eofblocks
16. xfs_free_eofblocks
17. xfs_alloc_file_space
18. xfs_unmap_extent
19. xfs_flush_unmap_range
20. xfs_free_file_space
21. xfs_zero_file_space
22. xfs_prepare_shift
23. xfs_collapse_file_space
24. xfs_insert_file_space
25. xfs_swap_extents_check_format
26. xfs_swap_extent_flush
27. xfs_swap_extent_rmap
28. xfs_swap_extent_forks
29. xfs_swap_change_owner
30. xfs_swap_extents

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2006 Silicon Graphics, Inc.
   4  * Copyright (c) 2012 Red Hat, Inc.
   5  * All Rights Reserved.
   6  */
   7 #include "xfs.h"
   8 #include "xfs_fs.h"
   9 #include "xfs_shared.h"
  10 #include "xfs_format.h"
  11 #include "xfs_log_format.h"
  12 #include "xfs_trans_resv.h"
  13 #include "xfs_bit.h"
  14 #include "xfs_mount.h"
  15 #include "xfs_defer.h"
  16 #include "xfs_inode.h"
  17 #include "xfs_btree.h"
  18 #include "xfs_trans.h"
  19 #include "xfs_alloc.h"
  20 #include "xfs_bmap.h"
  21 #include "xfs_bmap_util.h"
  22 #include "xfs_bmap_btree.h"
  23 #include "xfs_rtalloc.h"
  24 #include "xfs_error.h"
  25 #include "xfs_quota.h"
  26 #include "xfs_trans_space.h"
  27 #include "xfs_trace.h"
  28 #include "xfs_icache.h"
  29 #include "xfs_iomap.h"
  30 #include "xfs_reflink.h"
  31 
  32 /* Kernel only BMAP related definitions and functions */
  33 
  34 /*
  35  * Convert the given file system block to a disk block.  We have to treat it
  36  * differently based on whether the file is a real time file or not, because the
  37  * bmap code does.
  38  */
  39 xfs_daddr_t
  40 xfs_fsb_to_db(struct xfs_inode *ip, xfs_fsblock_t fsb)
  41 {
  42         if (XFS_IS_REALTIME_INODE(ip))
  43                 return XFS_FSB_TO_BB(ip->i_mount, fsb);
  44         return XFS_FSB_TO_DADDR(ip->i_mount, fsb);
  45 }
  46 
  47 /*
  48  * Routine to zero an extent on disk allocated to the specific inode.
  49  *
  50  * The VFS functions take a linearised filesystem block offset, so we have to
  51  * convert the sparse xfs fsb to the right format first.
  52  * VFS types are real funky, too.
  53  */
  54 int
  55 xfs_zero_extent(
  56         struct xfs_inode *ip,
  57         xfs_fsblock_t   start_fsb,
  58         xfs_off_t       count_fsb)
  59 {
  60         struct xfs_mount *mp = ip->i_mount;
  61         xfs_daddr_t     sector = xfs_fsb_to_db(ip, start_fsb);
  62         sector_t        block = XFS_BB_TO_FSBT(mp, sector);
  63 
  64         return blkdev_issue_zeroout(xfs_find_bdev_for_inode(VFS_I(ip)),
  65                 block << (mp->m_super->s_blocksize_bits - 9),
  66                 count_fsb << (mp->m_super->s_blocksize_bits - 9),
  67                 GFP_NOFS, 0);
  68 }
  69 
  70 #ifdef CONFIG_XFS_RT
  71 int
  72 xfs_bmap_rtalloc(
  73         struct xfs_bmalloca     *ap)    /* bmap alloc argument struct */
  74 {
  75         int             error;          /* error return value */
  76         xfs_mount_t     *mp;            /* mount point structure */
  77         xfs_extlen_t    prod = 0;       /* product factor for allocators */
  78         xfs_extlen_t    mod = 0;        /* product factor for allocators */
  79         xfs_extlen_t    ralen = 0;      /* realtime allocation length */
  80         xfs_extlen_t    align;          /* minimum allocation alignment */
  81         xfs_rtblock_t   rtb;
  82 
  83         mp = ap->ip->i_mount;
  84         align = xfs_get_extsz_hint(ap->ip);
  85         prod = align / mp->m_sb.sb_rextsize;
  86         error = xfs_bmap_extsize_align(mp, &ap->got, &ap->prev,
  87                                         align, 1, ap->eof, 0,
  88                                         ap->conv, &ap->offset, &ap->length);
  89         if (error)
  90                 return error;
  91         ASSERT(ap->length);
  92         ASSERT(ap->length % mp->m_sb.sb_rextsize == 0);
  93 
  94         /*
  95          * If the offset & length are not perfectly aligned
  96          * then kill prod, it will just get us in trouble.
  97          */
  98         div_u64_rem(ap->offset, align, &mod);
  99         if (mod || ap->length % align)
 100                 prod = 1;
 101         /*
 102          * Set ralen to be the actual requested length in rtextents.
 103          */
 104         ralen = ap->length / mp->m_sb.sb_rextsize;
 105         /*
 106          * If the old value was close enough to MAXEXTLEN that
 107          * we rounded up to it, cut it back so it's valid again.
 108          * Note that if it's a really large request (bigger than
 109          * MAXEXTLEN), we don't hear about that number, and can't
 110          * adjust the starting point to match it.
 111          */
 112         if (ralen * mp->m_sb.sb_rextsize >= MAXEXTLEN)
 113                 ralen = MAXEXTLEN / mp->m_sb.sb_rextsize;
 114 
 115         /*
 116          * Lock out modifications to both the RT bitmap and summary inodes
 117          */
 118         xfs_ilock(mp->m_rbmip, XFS_ILOCK_EXCL|XFS_ILOCK_RTBITMAP);
 119         xfs_trans_ijoin(ap->tp, mp->m_rbmip, XFS_ILOCK_EXCL);
 120         xfs_ilock(mp->m_rsumip, XFS_ILOCK_EXCL|XFS_ILOCK_RTSUM);
 121         xfs_trans_ijoin(ap->tp, mp->m_rsumip, XFS_ILOCK_EXCL);
 122 
 123         /*
 124          * If it's an allocation to an empty file at offset 0,
 125          * pick an extent that will space things out in the rt area.
 126          */
 127         if (ap->eof && ap->offset == 0) {
 128                 xfs_rtblock_t uninitialized_var(rtx); /* realtime extent no */
 129 
 130                 error = xfs_rtpick_extent(mp, ap->tp, ralen, &rtx);
 131                 if (error)
 132                         return error;
 133                 ap->blkno = rtx * mp->m_sb.sb_rextsize;
 134         } else {
 135                 ap->blkno = 0;
 136         }
 137 
 138         xfs_bmap_adjacent(ap);
 139 
 140         /*
 141          * Realtime allocation, done through xfs_rtallocate_extent.
 142          */
 143         do_div(ap->blkno, mp->m_sb.sb_rextsize);
 144         rtb = ap->blkno;
 145         ap->length = ralen;
 146         error = xfs_rtallocate_extent(ap->tp, ap->blkno, 1, ap->length,
 147                                 &ralen, ap->wasdel, prod, &rtb);
 148         if (error)
 149                 return error;
 150 
 151         ap->blkno = rtb;
 152         if (ap->blkno != NULLFSBLOCK) {
 153                 ap->blkno *= mp->m_sb.sb_rextsize;
 154                 ralen *= mp->m_sb.sb_rextsize;
 155                 ap->length = ralen;
 156                 ap->ip->i_d.di_nblocks += ralen;
 157                 xfs_trans_log_inode(ap->tp, ap->ip, XFS_ILOG_CORE);
 158                 if (ap->wasdel)
 159                         ap->ip->i_delayed_blks -= ralen;
 160                 /*
 161                  * Adjust the disk quota also. This was reserved
 162                  * earlier.
 163                  */
 164                 xfs_trans_mod_dquot_byino(ap->tp, ap->ip,
 165                         ap->wasdel ? XFS_TRANS_DQ_DELRTBCOUNT :
 166                                         XFS_TRANS_DQ_RTBCOUNT, (long) ralen);
 167 
 168                 /* Zero the extent if we were asked to do so */
 169                 if (ap->datatype & XFS_ALLOC_USERDATA_ZERO) {
 170                         error = xfs_zero_extent(ap->ip, ap->blkno, ap->length);
 171                         if (error)
 172                                 return error;
 173                 }
 174         } else {
 175                 ap->length = 0;
 176         }
 177         return 0;
 178 }
 179 #endif /* CONFIG_XFS_RT */
 180 
 181 /*
 182  * Check if the endoff is outside the last extent. If so the caller will grow
 183  * the allocation to a stripe unit boundary.  All offsets are considered outside
 184  * the end of file for an empty fork, so 1 is returned in *eof in that case.
 185  */
 186 int
 187 xfs_bmap_eof(
 188         struct xfs_inode        *ip,
 189         xfs_fileoff_t           endoff,
 190         int                     whichfork,
 191         int                     *eof)
 192 {
 193         struct xfs_bmbt_irec    rec;
 194         int                     error;
 195 
 196         error = xfs_bmap_last_extent(NULL, ip, whichfork, &rec, eof);
 197         if (error || *eof)
 198                 return error;
 199 
 200         *eof = endoff >= rec.br_startoff + rec.br_blockcount;
 201         return 0;
 202 }
 203 
 204 /*
 205  * Extent tree block counting routines.
 206  */
 207 
 208 /*
 209  * Count leaf blocks given a range of extent records.  Delayed allocation
 210  * extents are not counted towards the totals.
 211  */
 212 xfs_extnum_t
 213 xfs_bmap_count_leaves(
 214         struct xfs_ifork        *ifp,
 215         xfs_filblks_t           *count)
 216 {
 217         struct xfs_iext_cursor  icur;
 218         struct xfs_bmbt_irec    got;
 219         xfs_extnum_t            numrecs = 0;
 220 
 221         for_each_xfs_iext(ifp, &icur, &got) {
 222                 if (!isnullstartblock(got.br_startblock)) {
 223                         *count += got.br_blockcount;
 224                         numrecs++;
 225                 }
 226         }
 227 
 228         return numrecs;
 229 }
 230 
 231 /*
 232  * Count leaf blocks given a range of extent records originally
 233  * in btree format.
 234  */
 235 STATIC void
 236 xfs_bmap_disk_count_leaves(
 237         struct xfs_mount        *mp,
 238         struct xfs_btree_block  *block,
 239         int                     numrecs,
 240         xfs_filblks_t           *count)
 241 {
 242         int             b;
 243         xfs_bmbt_rec_t  *frp;
 244 
 245         for (b = 1; b <= numrecs; b++) {
 246                 frp = XFS_BMBT_REC_ADDR(mp, block, b);
 247                 *count += xfs_bmbt_disk_get_blockcount(frp);
 248         }
 249 }
 250 
 251 /*
 252  * Recursively walks each level of a btree
 253  * to count total fsblocks in use.
 254  */
 255 STATIC int
 256 xfs_bmap_count_tree(
 257         struct xfs_mount        *mp,
 258         struct xfs_trans        *tp,
 259         struct xfs_ifork        *ifp,
 260         xfs_fsblock_t           blockno,
 261         int                     levelin,
 262         xfs_extnum_t            *nextents,
 263         xfs_filblks_t           *count)
 264 {
 265         int                     error;
 266         struct xfs_buf          *bp, *nbp;
 267         int                     level = levelin;
 268         __be64                  *pp;
 269         xfs_fsblock_t           bno = blockno;
 270         xfs_fsblock_t           nextbno;
 271         struct xfs_btree_block  *block, *nextblock;
 272         int                     numrecs;
 273 
 274         error = xfs_btree_read_bufl(mp, tp, bno, &bp, XFS_BMAP_BTREE_REF,
 275                                                 &xfs_bmbt_buf_ops);
 276         if (error)
 277                 return error;
 278         *count += 1;
 279         block = XFS_BUF_TO_BLOCK(bp);
 280 
 281         if (--level) {
 282                 /* Not at node above leaves, count this level of nodes */
 283                 nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
 284                 while (nextbno != NULLFSBLOCK) {
 285                         error = xfs_btree_read_bufl(mp, tp, nextbno, &nbp,
 286                                                 XFS_BMAP_BTREE_REF,
 287                                                 &xfs_bmbt_buf_ops);
 288                         if (error)
 289                                 return error;
 290                         *count += 1;
 291                         nextblock = XFS_BUF_TO_BLOCK(nbp);
 292                         nextbno = be64_to_cpu(nextblock->bb_u.l.bb_rightsib);
 293                         xfs_trans_brelse(tp, nbp);
 294                 }
 295 
 296                 /* Dive to the next level */
 297                 pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
 298                 bno = be64_to_cpu(*pp);
 299                 error = xfs_bmap_count_tree(mp, tp, ifp, bno, level, nextents,
 300                                 count);
 301                 if (error) {
 302                         xfs_trans_brelse(tp, bp);
 303                         XFS_ERROR_REPORT("xfs_bmap_count_tree(1)",
 304                                          XFS_ERRLEVEL_LOW, mp);
 305                         return -EFSCORRUPTED;
 306                 }
 307                 xfs_trans_brelse(tp, bp);
 308         } else {
 309                 /* count all level 1 nodes and their leaves */
 310                 for (;;) {
 311                         nextbno = be64_to_cpu(block->bb_u.l.bb_rightsib);
 312                         numrecs = be16_to_cpu(block->bb_numrecs);
 313                         (*nextents) += numrecs;
 314                         xfs_bmap_disk_count_leaves(mp, block, numrecs, count);
 315                         xfs_trans_brelse(tp, bp);
 316                         if (nextbno == NULLFSBLOCK)
 317                                 break;
 318                         bno = nextbno;
 319                         error = xfs_btree_read_bufl(mp, tp, bno, &bp,
 320                                                 XFS_BMAP_BTREE_REF,
 321                                                 &xfs_bmbt_buf_ops);
 322                         if (error)
 323                                 return error;
 324                         *count += 1;
 325                         block = XFS_BUF_TO_BLOCK(bp);
 326                 }
 327         }
 328         return 0;
 329 }
 330 
 331 /*
 332  * Count fsblocks of the given fork.  Delayed allocation extents are
 333  * not counted towards the totals.
 334  */
 335 int
 336 xfs_bmap_count_blocks(
 337         struct xfs_trans        *tp,
 338         struct xfs_inode        *ip,
 339         int                     whichfork,
 340         xfs_extnum_t            *nextents,
 341         xfs_filblks_t           *count)
 342 {
 343         struct xfs_mount        *mp;    /* file system mount structure */
 344         __be64                  *pp;    /* pointer to block address */
 345         struct xfs_btree_block  *block; /* current btree block */
 346         struct xfs_ifork        *ifp;   /* fork structure */
 347         xfs_fsblock_t           bno;    /* block # of "block" */
 348         int                     level;  /* btree level, for checking */
 349         int                     error;
 350 
 351         bno = NULLFSBLOCK;
 352         mp = ip->i_mount;
 353         *nextents = 0;
 354         *count = 0;
 355         ifp = XFS_IFORK_PTR(ip, whichfork);
 356         if (!ifp)
 357                 return 0;
 358 
 359         switch (XFS_IFORK_FORMAT(ip, whichfork)) {
 360         case XFS_DINODE_FMT_EXTENTS:
 361                 *nextents = xfs_bmap_count_leaves(ifp, count);
 362                 return 0;
 363         case XFS_DINODE_FMT_BTREE:
 364                 if (!(ifp->if_flags & XFS_IFEXTENTS)) {
 365                         error = xfs_iread_extents(tp, ip, whichfork);
 366                         if (error)
 367                                 return error;
 368                 }
 369 
 370                 /*
 371                  * Root level must use BMAP_BROOT_PTR_ADDR macro to get ptr out.
 372                  */
 373                 block = ifp->if_broot;
 374                 level = be16_to_cpu(block->bb_level);
 375                 ASSERT(level > 0);
 376                 pp = XFS_BMAP_BROOT_PTR_ADDR(mp, block, 1, ifp->if_broot_bytes);
 377                 bno = be64_to_cpu(*pp);
 378                 ASSERT(bno != NULLFSBLOCK);
 379                 ASSERT(XFS_FSB_TO_AGNO(mp, bno) < mp->m_sb.sb_agcount);
 380                 ASSERT(XFS_FSB_TO_AGBNO(mp, bno) < mp->m_sb.sb_agblocks);
 381 
 382                 error = xfs_bmap_count_tree(mp, tp, ifp, bno, level,
 383                                 nextents, count);
 384                 if (error) {
 385                         XFS_ERROR_REPORT("xfs_bmap_count_blocks(2)",
 386                                         XFS_ERRLEVEL_LOW, mp);
 387                         return -EFSCORRUPTED;
 388                 }
 389                 return 0;
 390         }
 391 
 392         return 0;
 393 }
 394 
 395 static int
 396 xfs_getbmap_report_one(
 397         struct xfs_inode        *ip,
 398         struct getbmapx         *bmv,
 399         struct kgetbmap         *out,
 400         int64_t                 bmv_end,
 401         struct xfs_bmbt_irec    *got)
 402 {
 403         struct kgetbmap         *p = out + bmv->bmv_entries;
 404         bool                    shared = false;
 405         int                     error;
 406 
 407         error = xfs_reflink_trim_around_shared(ip, got, &shared);
 408         if (error)
 409                 return error;
 410 
 411         if (isnullstartblock(got->br_startblock) ||
 412             got->br_startblock == DELAYSTARTBLOCK) {
 413                 /*
 414                  * Delalloc extents that start beyond EOF can occur due to
 415                  * speculative EOF allocation when the delalloc extent is larger
 416                  * than the largest freespace extent at conversion time.  These
 417                  * extents cannot be converted by data writeback, so can exist
 418                  * here even if we are not supposed to be finding delalloc
 419                  * extents.
 420                  */
 421                 if (got->br_startoff < XFS_B_TO_FSB(ip->i_mount, XFS_ISIZE(ip)))
 422                         ASSERT((bmv->bmv_iflags & BMV_IF_DELALLOC) != 0);
 423 
 424                 p->bmv_oflags |= BMV_OF_DELALLOC;
 425                 p->bmv_block = -2;
 426         } else {
 427                 p->bmv_block = xfs_fsb_to_db(ip, got->br_startblock);
 428         }
 429 
 430         if (got->br_state == XFS_EXT_UNWRITTEN &&
 431             (bmv->bmv_iflags & BMV_IF_PREALLOC))
 432                 p->bmv_oflags |= BMV_OF_PREALLOC;
 433 
 434         if (shared)
 435                 p->bmv_oflags |= BMV_OF_SHARED;
 436 
 437         p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, got->br_startoff);
 438         p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, got->br_blockcount);
 439 
 440         bmv->bmv_offset = p->bmv_offset + p->bmv_length;
 441         bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
 442         bmv->bmv_entries++;
 443         return 0;
 444 }
 445 
 446 static void
 447 xfs_getbmap_report_hole(
 448         struct xfs_inode        *ip,
 449         struct getbmapx         *bmv,
 450         struct kgetbmap         *out,
 451         int64_t                 bmv_end,
 452         xfs_fileoff_t           bno,
 453         xfs_fileoff_t           end)
 454 {
 455         struct kgetbmap         *p = out + bmv->bmv_entries;
 456 
 457         if (bmv->bmv_iflags & BMV_IF_NO_HOLES)
 458                 return;
 459 
 460         p->bmv_block = -1;
 461         p->bmv_offset = XFS_FSB_TO_BB(ip->i_mount, bno);
 462         p->bmv_length = XFS_FSB_TO_BB(ip->i_mount, end - bno);
 463 
 464         bmv->bmv_offset = p->bmv_offset + p->bmv_length;
 465         bmv->bmv_length = max(0LL, bmv_end - bmv->bmv_offset);
 466         bmv->bmv_entries++;
 467 }
 468 
 469 static inline bool
 470 xfs_getbmap_full(
 471         struct getbmapx         *bmv)
 472 {
 473         return bmv->bmv_length == 0 || bmv->bmv_entries >= bmv->bmv_count - 1;
 474 }
 475 
 476 static bool
 477 xfs_getbmap_next_rec(
 478         struct xfs_bmbt_irec    *rec,
 479         xfs_fileoff_t           total_end)
 480 {
 481         xfs_fileoff_t           end = rec->br_startoff + rec->br_blockcount;
 482 
 483         if (end == total_end)
 484                 return false;
 485 
 486         rec->br_startoff += rec->br_blockcount;
 487         if (!isnullstartblock(rec->br_startblock) &&
 488             rec->br_startblock != DELAYSTARTBLOCK)
 489                 rec->br_startblock += rec->br_blockcount;
 490         rec->br_blockcount = total_end - end;
 491         return true;
 492 }
 493 
 494 /*
 495  * Get inode's extents as described in bmv, and format for output.
 496  * Calls formatter to fill the user's buffer until all extents
 497  * are mapped, until the passed-in bmv->bmv_count slots have
 498  * been filled, or until the formatter short-circuits the loop,
 499  * if it is tracking filled-in extents on its own.
 500  */
 501 int                                             /* error code */
 502 xfs_getbmap(
 503         struct xfs_inode        *ip,
 504         struct getbmapx         *bmv,           /* user bmap structure */
 505         struct kgetbmap         *out)
 506 {
 507         struct xfs_mount        *mp = ip->i_mount;
 508         int                     iflags = bmv->bmv_iflags;
 509         int                     whichfork, lock, error = 0;
 510         int64_t                 bmv_end, max_len;
 511         xfs_fileoff_t           bno, first_bno;
 512         struct xfs_ifork        *ifp;
 513         struct xfs_bmbt_irec    got, rec;
 514         xfs_filblks_t           len;
 515         struct xfs_iext_cursor  icur;
 516 
 517         if (bmv->bmv_iflags & ~BMV_IF_VALID)
 518                 return -EINVAL;
 519 #ifndef DEBUG
 520         /* Only allow CoW fork queries if we're debugging. */
 521         if (iflags & BMV_IF_COWFORK)
 522                 return -EINVAL;
 523 #endif
 524         if ((iflags & BMV_IF_ATTRFORK) && (iflags & BMV_IF_COWFORK))
 525                 return -EINVAL;
 526 
 527         if (bmv->bmv_length < -1)
 528                 return -EINVAL;
 529         bmv->bmv_entries = 0;
 530         if (bmv->bmv_length == 0)
 531                 return 0;
 532 
 533         if (iflags & BMV_IF_ATTRFORK)
 534                 whichfork = XFS_ATTR_FORK;
 535         else if (iflags & BMV_IF_COWFORK)
 536                 whichfork = XFS_COW_FORK;
 537         else
 538                 whichfork = XFS_DATA_FORK;
 539         ifp = XFS_IFORK_PTR(ip, whichfork);
 540 
 541         xfs_ilock(ip, XFS_IOLOCK_SHARED);
 542         switch (whichfork) {
 543         case XFS_ATTR_FORK:
 544                 if (!XFS_IFORK_Q(ip))
 545                         goto out_unlock_iolock;
 546 
 547                 max_len = 1LL << 32;
 548                 lock = xfs_ilock_attr_map_shared(ip);
 549                 break;
 550         case XFS_COW_FORK:
 551                 /* No CoW fork? Just return */
 552                 if (!ifp)
 553                         goto out_unlock_iolock;
 554 
 555                 if (xfs_get_cowextsz_hint(ip))
 556                         max_len = mp->m_super->s_maxbytes;
 557                 else
 558                         max_len = XFS_ISIZE(ip);
 559 
 560                 lock = XFS_ILOCK_SHARED;
 561                 xfs_ilock(ip, lock);
 562                 break;
 563         case XFS_DATA_FORK:
 564                 if (!(iflags & BMV_IF_DELALLOC) &&
 565                     (ip->i_delayed_blks || XFS_ISIZE(ip) > ip->i_d.di_size)) {
 566                         error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
 567                         if (error)
 568                                 goto out_unlock_iolock;
 569 
 570                         /*
 571                          * Even after flushing the inode, there can still be
 572                          * delalloc blocks on the inode beyond EOF due to
 573                          * speculative preallocation.  These are not removed
 574                          * until the release function is called or the inode
 575                          * is inactivated.  Hence we cannot assert here that
 576                          * ip->i_delayed_blks == 0.
 577                          */
 578                 }
 579 
 580                 if (xfs_get_extsz_hint(ip) ||
 581                     (ip->i_d.di_flags &
 582                      (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))
 583                         max_len = mp->m_super->s_maxbytes;
 584                 else
 585                         max_len = XFS_ISIZE(ip);
 586 
 587                 lock = xfs_ilock_data_map_shared(ip);
 588                 break;
 589         }
 590 
 591         switch (XFS_IFORK_FORMAT(ip, whichfork)) {
 592         case XFS_DINODE_FMT_EXTENTS:
 593         case XFS_DINODE_FMT_BTREE:
 594                 break;
 595         case XFS_DINODE_FMT_LOCAL:
 596                 /* Local format inode forks report no extents. */
 597                 goto out_unlock_ilock;
 598         default:
 599                 error = -EINVAL;
 600                 goto out_unlock_ilock;
 601         }
 602 
 603         if (bmv->bmv_length == -1) {
 604                 max_len = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, max_len));
 605                 bmv->bmv_length = max(0LL, max_len - bmv->bmv_offset);
 606         }
 607 
 608         bmv_end = bmv->bmv_offset + bmv->bmv_length;
 609 
 610         first_bno = bno = XFS_BB_TO_FSBT(mp, bmv->bmv_offset);
 611         len = XFS_BB_TO_FSB(mp, bmv->bmv_length);
 612 
 613         if (!(ifp->if_flags & XFS_IFEXTENTS)) {
 614                 error = xfs_iread_extents(NULL, ip, whichfork);
 615                 if (error)
 616                         goto out_unlock_ilock;
 617         }
 618 
 619         if (!xfs_iext_lookup_extent(ip, ifp, bno, &icur, &got)) {
 620                 /*
 621                  * Report a whole-file hole if the delalloc flag is set to
 622                  * stay compatible with the old implementation.
 623                  */
 624                 if (iflags & BMV_IF_DELALLOC)
 625                         xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
 626                                         XFS_B_TO_FSB(mp, XFS_ISIZE(ip)));
 627                 goto out_unlock_ilock;
 628         }
 629 
 630         while (!xfs_getbmap_full(bmv)) {
 631                 xfs_trim_extent(&got, first_bno, len);
 632 
 633                 /*
 634                  * Report an entry for a hole if this extent doesn't directly
 635                  * follow the previous one.
 636                  */
 637                 if (got.br_startoff > bno) {
 638                         xfs_getbmap_report_hole(ip, bmv, out, bmv_end, bno,
 639                                         got.br_startoff);
 640                         if (xfs_getbmap_full(bmv))
 641                                 break;
 642                 }
 643 
 644                 /*
 645                  * In order to report shared extents accurately, we report each
 646                  * distinct shared / unshared part of a single bmbt record with
 647                  * an individual getbmapx record.
 648                  */
 649                 bno = got.br_startoff + got.br_blockcount;
 650                 rec = got;
 651                 do {
 652                         error = xfs_getbmap_report_one(ip, bmv, out, bmv_end,
 653                                         &rec);
 654                         if (error || xfs_getbmap_full(bmv))
 655                                 goto out_unlock_ilock;
 656                 } while (xfs_getbmap_next_rec(&rec, bno));
 657 
 658                 if (!xfs_iext_next_extent(ifp, &icur, &got)) {
 659                         xfs_fileoff_t   end = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
 660 
 661                         out[bmv->bmv_entries - 1].bmv_oflags |= BMV_OF_LAST;
 662 
 663                         if (whichfork != XFS_ATTR_FORK && bno < end &&
 664                             !xfs_getbmap_full(bmv)) {
 665                                 xfs_getbmap_report_hole(ip, bmv, out, bmv_end,
 666                                                 bno, end);
 667                         }
 668                         break;
 669                 }
 670 
 671                 if (bno >= first_bno + len)
 672                         break;
 673         }
 674 
 675 out_unlock_ilock:
 676         xfs_iunlock(ip, lock);
 677 out_unlock_iolock:
 678         xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 679         return error;
 680 }
 681 
 682 /*
 683  * Dead simple method of punching delalyed allocation blocks from a range in
 684  * the inode.  This will always punch out both the start and end blocks, even
 685  * if the ranges only partially overlap them, so it is up to the caller to
 686  * ensure that partial blocks are not passed in.
 687  */
 688 int
 689 xfs_bmap_punch_delalloc_range(
 690         struct xfs_inode        *ip,
 691         xfs_fileoff_t           start_fsb,
 692         xfs_fileoff_t           length)
 693 {
 694         struct xfs_ifork        *ifp = &ip->i_df;
 695         xfs_fileoff_t           end_fsb = start_fsb + length;
 696         struct xfs_bmbt_irec    got, del;
 697         struct xfs_iext_cursor  icur;
 698         int                     error = 0;
 699 
 700         ASSERT(ifp->if_flags & XFS_IFEXTENTS);
 701 
 702         xfs_ilock(ip, XFS_ILOCK_EXCL);
 703         if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got))
 704                 goto out_unlock;
 705 
 706         while (got.br_startoff + got.br_blockcount > start_fsb) {
 707                 del = got;
 708                 xfs_trim_extent(&del, start_fsb, length);
 709 
 710                 /*
 711                  * A delete can push the cursor forward. Step back to the
 712                  * previous extent on non-delalloc or extents outside the
 713                  * target range.
 714                  */
 715                 if (!del.br_blockcount ||
 716                     !isnullstartblock(del.br_startblock)) {
 717                         if (!xfs_iext_prev_extent(ifp, &icur, &got))
 718                                 break;
 719                         continue;
 720                 }
 721 
 722                 error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur,
 723                                                   &got, &del);
 724                 if (error || !xfs_iext_get_extent(ifp, &icur, &got))
 725                         break;
 726         }
 727 
 728 out_unlock:
 729         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 730         return error;
 731 }
 732 
 733 /*
 734  * Test whether it is appropriate to check an inode for and free post EOF
 735  * blocks. The 'force' parameter determines whether we should also consider
 736  * regular files that are marked preallocated or append-only.
 737  */
 738 bool
 739 xfs_can_free_eofblocks(struct xfs_inode *ip, bool force)
 740 {
 741         /* prealloc/delalloc exists only on regular files */
 742         if (!S_ISREG(VFS_I(ip)->i_mode))
 743                 return false;
 744 
 745         /*
 746          * Zero sized files with no cached pages and delalloc blocks will not
 747          * have speculative prealloc/delalloc blocks to remove.
 748          */
 749         if (VFS_I(ip)->i_size == 0 &&
 750             VFS_I(ip)->i_mapping->nrpages == 0 &&
 751             ip->i_delayed_blks == 0)
 752                 return false;
 753 
 754         /* If we haven't read in the extent list, then don't do it now. */
 755         if (!(ip->i_df.if_flags & XFS_IFEXTENTS))
 756                 return false;
 757 
 758         /*
 759          * Do not free real preallocated or append-only files unless the file
 760          * has delalloc blocks and we are forced to remove them.
 761          */
 762         if (ip->i_d.di_flags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND))
 763                 if (!force || ip->i_delayed_blks == 0)
 764                         return false;
 765 
 766         return true;
 767 }
 768 
 769 /*
 770  * This is called to free any blocks beyond eof. The caller must hold
 771  * IOLOCK_EXCL unless we are in the inode reclaim path and have the only
 772  * reference to the inode.
 773  */
 774 int
 775 xfs_free_eofblocks(
 776         struct xfs_inode        *ip)
 777 {
 778         struct xfs_trans        *tp;
 779         int                     error;
 780         xfs_fileoff_t           end_fsb;
 781         xfs_fileoff_t           last_fsb;
 782         xfs_filblks_t           map_len;
 783         int                     nimaps;
 784         struct xfs_bmbt_irec    imap;
 785         struct xfs_mount        *mp = ip->i_mount;
 786 
 787         /*
 788          * Figure out if there are any blocks beyond the end
 789          * of the file.  If not, then there is nothing to do.
 790          */
 791         end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_ISIZE(ip));
 792         last_fsb = XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
 793         if (last_fsb <= end_fsb)
 794                 return 0;
 795         map_len = last_fsb - end_fsb;
 796 
 797         nimaps = 1;
 798         xfs_ilock(ip, XFS_ILOCK_SHARED);
 799         error = xfs_bmapi_read(ip, end_fsb, map_len, &imap, &nimaps, 0);
 800         xfs_iunlock(ip, XFS_ILOCK_SHARED);
 801 
 802         /*
 803          * If there are blocks after the end of file, truncate the file to its
 804          * current size to free them up.
 805          */
 806         if (!error && (nimaps != 0) &&
 807             (imap.br_startblock != HOLESTARTBLOCK ||
 808              ip->i_delayed_blks)) {
 809                 /*
 810                  * Attach the dquots to the inode up front.
 811                  */
 812                 error = xfs_qm_dqattach(ip);
 813                 if (error)
 814                         return error;
 815 
 816                 /* wait on dio to ensure i_size has settled */
 817                 inode_dio_wait(VFS_I(ip));
 818 
 819                 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0,
 820                                 &tp);
 821                 if (error) {
 822                         ASSERT(XFS_FORCED_SHUTDOWN(mp));
 823                         return error;
 824                 }
 825 
 826                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 827                 xfs_trans_ijoin(tp, ip, 0);
 828 
 829                 /*
 830                  * Do not update the on-disk file size.  If we update the
 831                  * on-disk file size and then the system crashes before the
 832                  * contents of the file are flushed to disk then the files
 833                  * may be full of holes (ie NULL files bug).
 834                  */
 835                 error = xfs_itruncate_extents_flags(&tp, ip, XFS_DATA_FORK,
 836                                         XFS_ISIZE(ip), XFS_BMAPI_NODISCARD);
 837                 if (error) {
 838                         /*
 839                          * If we get an error at this point we simply don't
 840                          * bother truncating the file.
 841                          */
 842                         xfs_trans_cancel(tp);
 843                 } else {
 844                         error = xfs_trans_commit(tp);
 845                         if (!error)
 846                                 xfs_inode_clear_eofblocks_tag(ip);
 847                 }
 848 
 849                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 850         }
 851         return error;
 852 }
 853 
 854 int
 855 xfs_alloc_file_space(
 856         struct xfs_inode        *ip,
 857         xfs_off_t               offset,
 858         xfs_off_t               len,
 859         int                     alloc_type)
 860 {
 861         xfs_mount_t             *mp = ip->i_mount;
 862         xfs_off_t               count;
 863         xfs_filblks_t           allocated_fsb;
 864         xfs_filblks_t           allocatesize_fsb;
 865         xfs_extlen_t            extsz, temp;
 866         xfs_fileoff_t           startoffset_fsb;
 867         xfs_fileoff_t           endoffset_fsb;
 868         int                     nimaps;
 869         int                     quota_flag;
 870         int                     rt;
 871         xfs_trans_t             *tp;
 872         xfs_bmbt_irec_t         imaps[1], *imapp;
 873         uint                    qblocks, resblks, resrtextents;
 874         int                     error;
 875 
 876         trace_xfs_alloc_file_space(ip);
 877 
 878         if (XFS_FORCED_SHUTDOWN(mp))
 879                 return -EIO;
 880 
 881         error = xfs_qm_dqattach(ip);
 882         if (error)
 883                 return error;
 884 
 885         if (len <= 0)
 886                 return -EINVAL;
 887 
 888         rt = XFS_IS_REALTIME_INODE(ip);
 889         extsz = xfs_get_extsz_hint(ip);
 890 
 891         count = len;
 892         imapp = &imaps[0];
 893         nimaps = 1;
 894         startoffset_fsb = XFS_B_TO_FSBT(mp, offset);
 895         endoffset_fsb = XFS_B_TO_FSB(mp, offset + count);
 896         allocatesize_fsb = endoffset_fsb - startoffset_fsb;
 897 
 898         /*
 899          * Allocate file space until done or until there is an error
 900          */
 901         while (allocatesize_fsb && !error) {
 902                 xfs_fileoff_t   s, e;
 903 
 904                 /*
 905                  * Determine space reservations for data/realtime.
 906                  */
 907                 if (unlikely(extsz)) {
 908                         s = startoffset_fsb;
 909                         do_div(s, extsz);
 910                         s *= extsz;
 911                         e = startoffset_fsb + allocatesize_fsb;
 912                         div_u64_rem(startoffset_fsb, extsz, &temp);
 913                         if (temp)
 914                                 e += temp;
 915                         div_u64_rem(e, extsz, &temp);
 916                         if (temp)
 917                                 e += extsz - temp;
 918                 } else {
 919                         s = 0;
 920                         e = allocatesize_fsb;
 921                 }
 922 
 923                 /*
 924                  * The transaction reservation is limited to a 32-bit block
 925                  * count, hence we need to limit the number of blocks we are
 926                  * trying to reserve to avoid an overflow. We can't allocate
 927                  * more than @nimaps extents, and an extent is limited on disk
 928                  * to MAXEXTLEN (21 bits), so use that to enforce the limit.
 929                  */
 930                 resblks = min_t(xfs_fileoff_t, (e - s), (MAXEXTLEN * nimaps));
 931                 if (unlikely(rt)) {
 932                         resrtextents = qblocks = resblks;
 933                         resrtextents /= mp->m_sb.sb_rextsize;
 934                         resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
 935                         quota_flag = XFS_QMOPT_RES_RTBLKS;
 936                 } else {
 937                         resrtextents = 0;
 938                         resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resblks);
 939                         quota_flag = XFS_QMOPT_RES_REGBLKS;
 940                 }
 941 
 942                 /*
 943                  * Allocate and setup the transaction.
 944                  */
 945                 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks,
 946                                 resrtextents, 0, &tp);
 947 
 948                 /*
 949                  * Check for running out of space
 950                  */
 951                 if (error) {
 952                         /*
 953                          * Free the transaction structure.
 954                          */
 955                         ASSERT(error == -ENOSPC || XFS_FORCED_SHUTDOWN(mp));
 956                         break;
 957                 }
 958                 xfs_ilock(ip, XFS_ILOCK_EXCL);
 959                 error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks,
 960                                                       0, quota_flag);
 961                 if (error)
 962                         goto error1;
 963 
 964                 xfs_trans_ijoin(tp, ip, 0);
 965 
 966                 error = xfs_bmapi_write(tp, ip, startoffset_fsb,
 967                                         allocatesize_fsb, alloc_type, resblks,
 968                                         imapp, &nimaps);
 969                 if (error)
 970                         goto error0;
 971 
 972                 /*
 973                  * Complete the transaction
 974                  */
 975                 error = xfs_trans_commit(tp);
 976                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
 977                 if (error)
 978                         break;
 979 
 980                 allocated_fsb = imapp->br_blockcount;
 981 
 982                 if (nimaps == 0) {
 983                         error = -ENOSPC;
 984                         break;
 985                 }
 986 
 987                 startoffset_fsb += allocated_fsb;
 988                 allocatesize_fsb -= allocated_fsb;
 989         }
 990 
 991         return error;
 992 
 993 error0: /* unlock inode, unreserve quota blocks, cancel trans */
 994         xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag);
 995 
 996 error1: /* Just cancel transaction */
 997         xfs_trans_cancel(tp);
 998         xfs_iunlock(ip, XFS_ILOCK_EXCL);
 999         return error;
1000 }
1001 
1002 static int
1003 xfs_unmap_extent(
1004         struct xfs_inode        *ip,
1005         xfs_fileoff_t           startoffset_fsb,
1006         xfs_filblks_t           len_fsb,
1007         int                     *done)
1008 {
1009         struct xfs_mount        *mp = ip->i_mount;
1010         struct xfs_trans        *tp;
1011         uint                    resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
1012         int                     error;
1013 
1014         error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
1015         if (error) {
1016                 ASSERT(error == -ENOSPC || XFS_FORCED_SHUTDOWN(mp));
1017                 return error;
1018         }
1019 
1020         xfs_ilock(ip, XFS_ILOCK_EXCL);
1021         error = xfs_trans_reserve_quota(tp, mp, ip->i_udquot, ip->i_gdquot,
1022                         ip->i_pdquot, resblks, 0, XFS_QMOPT_RES_REGBLKS);
1023         if (error)
1024                 goto out_trans_cancel;
1025 
1026         xfs_trans_ijoin(tp, ip, 0);
1027 
1028         error = xfs_bunmapi(tp, ip, startoffset_fsb, len_fsb, 0, 2, done);
1029         if (error)
1030                 goto out_trans_cancel;
1031 
1032         error = xfs_trans_commit(tp);
1033 out_unlock:
1034         xfs_iunlock(ip, XFS_ILOCK_EXCL);
1035         return error;
1036 
1037 out_trans_cancel:
1038         xfs_trans_cancel(tp);
1039         goto out_unlock;
1040 }
1041 
1042 int
1043 xfs_flush_unmap_range(
1044         struct xfs_inode        *ip,
1045         xfs_off_t               offset,
1046         xfs_off_t               len)
1047 {
1048         struct xfs_mount        *mp = ip->i_mount;
1049         struct inode            *inode = VFS_I(ip);
1050         xfs_off_t               rounding, start, end;
1051         int                     error;
1052 
1053         /* wait for the completion of any pending DIOs */
1054         inode_dio_wait(inode);
1055 
1056         rounding = max_t(xfs_off_t, 1 << mp->m_sb.sb_blocklog, PAGE_SIZE);
1057         start = round_down(offset, rounding);
1058         end = round_up(offset + len, rounding) - 1;
1059 
1060         error = filemap_write_and_wait_range(inode->i_mapping, start, end);
1061         if (error)
1062                 return error;
1063         truncate_pagecache_range(inode, start, end);
1064         return 0;
1065 }
1066 
1067 int
1068 xfs_free_file_space(
1069         struct xfs_inode        *ip,
1070         xfs_off_t               offset,
1071         xfs_off_t               len)
1072 {
1073         struct xfs_mount        *mp = ip->i_mount;
1074         xfs_fileoff_t           startoffset_fsb;
1075         xfs_fileoff_t           endoffset_fsb;
1076         int                     done = 0, error;
1077 
1078         trace_xfs_free_file_space(ip);
1079 
1080         error = xfs_qm_dqattach(ip);
1081         if (error)
1082                 return error;
1083 
1084         if (len <= 0)   /* if nothing being freed */
1085                 return 0;
1086 
1087         error = xfs_flush_unmap_range(ip, offset, len);
1088         if (error)
1089                 return error;
1090 
1091         startoffset_fsb = XFS_B_TO_FSB(mp, offset);
1092         endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
1093 
1094         /*
1095          * Need to zero the stuff we're not freeing, on disk.
1096          */
1097         if (endoffset_fsb > startoffset_fsb) {
1098                 while (!done) {
1099                         error = xfs_unmap_extent(ip, startoffset_fsb,
1100                                         endoffset_fsb - startoffset_fsb, &done);
1101                         if (error)
1102                                 return error;
1103                 }
1104         }
1105 
1106         /*
1107          * Now that we've unmap all full blocks we'll have to zero out any
1108          * partial block at the beginning and/or end.  iomap_zero_range is smart
1109          * enough to skip any holes, including those we just created, but we
1110          * must take care not to zero beyond EOF and enlarge i_size.
1111          */
1112         if (offset >= XFS_ISIZE(ip))
1113                 return 0;
1114         if (offset + len > XFS_ISIZE(ip))
1115                 len = XFS_ISIZE(ip) - offset;
1116         error = iomap_zero_range(VFS_I(ip), offset, len, NULL, &xfs_iomap_ops);
1117         if (error)
1118                 return error;
1119 
1120         /*
1121          * If we zeroed right up to EOF and EOF straddles a page boundary we
1122          * must make sure that the post-EOF area is also zeroed because the
1123          * page could be mmap'd and iomap_zero_range doesn't do that for us.
1124          * Writeback of the eof page will do this, albeit clumsily.
1125          */
1126         if (offset + len >= XFS_ISIZE(ip) && offset_in_page(offset + len) > 0) {
1127                 error = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
1128                                 round_down(offset + len, PAGE_SIZE), LLONG_MAX);
1129         }
1130 
1131         return error;
1132 }
1133 
1134 /*
1135  * Preallocate and zero a range of a file. This mechanism has the allocation
1136  * semantics of fallocate and in addition converts data in the range to zeroes.
1137  */
1138 int
1139 xfs_zero_file_space(
1140         struct xfs_inode        *ip,
1141         xfs_off_t               offset,
1142         xfs_off_t               len)
1143 {
1144         struct xfs_mount        *mp = ip->i_mount;
1145         uint                    blksize;
1146         int                     error;
1147 
1148         trace_xfs_zero_file_space(ip);
1149 
1150         blksize = 1 << mp->m_sb.sb_blocklog;
1151 
1152         /*
1153          * Punch a hole and prealloc the range. We use hole punch rather than
1154          * unwritten extent conversion for two reasons:
1155          *
1156          * 1.) Hole punch handles partial block zeroing for us.
1157          *
1158          * 2.) If prealloc returns ENOSPC, the file range is still zero-valued
1159          * by virtue of the hole punch.
1160          */
1161         error = xfs_free_file_space(ip, offset, len);
1162         if (error || xfs_is_always_cow_inode(ip))
1163                 return error;
1164 
1165         return xfs_alloc_file_space(ip, round_down(offset, blksize),
1166                                      round_up(offset + len, blksize) -
1167                                      round_down(offset, blksize),
1168                                      XFS_BMAPI_PREALLOC);
1169 }
1170 
1171 static int
1172 xfs_prepare_shift(
1173         struct xfs_inode        *ip,
1174         loff_t                  offset)
1175 {
1176         int                     error;
1177 
1178         /*
1179          * Trim eofblocks to avoid shifting uninitialized post-eof preallocation
1180          * into the accessible region of the file.
1181          */
1182         if (xfs_can_free_eofblocks(ip, true)) {
1183                 error = xfs_free_eofblocks(ip);
1184                 if (error)
1185                         return error;
1186         }
1187 
1188         /*
1189          * Writeback and invalidate cache for the remainder of the file as we're
1190          * about to shift down every extent from offset to EOF.
1191          */
1192         error = xfs_flush_unmap_range(ip, offset, XFS_ISIZE(ip));
1193         if (error)
1194                 return error;
1195 
1196         /*
1197          * Clean out anything hanging around in the cow fork now that
1198          * we've flushed all the dirty data out to disk to avoid having
1199          * CoW extents at the wrong offsets.
1200          */
1201         if (xfs_inode_has_cow_data(ip)) {
1202                 error = xfs_reflink_cancel_cow_range(ip, offset, NULLFILEOFF,
1203                                 true);
1204                 if (error)
1205                         return error;
1206         }
1207 
1208         return 0;
1209 }
1210 
1211 /*
1212  * xfs_collapse_file_space()
1213  *      This routine frees disk space and shift extent for the given file.
1214  *      The first thing we do is to free data blocks in the specified range
1215  *      by calling xfs_free_file_space(). It would also sync dirty data
1216  *      and invalidate page cache over the region on which collapse range
1217  *      is working. And Shift extent records to the left to cover a hole.
1218  * RETURNS:
1219  *      0 on success
1220  *      errno on error
1221  *
1222  */
1223 int
1224 xfs_collapse_file_space(
1225         struct xfs_inode        *ip,
1226         xfs_off_t               offset,
1227         xfs_off_t               len)
1228 {
1229         struct xfs_mount        *mp = ip->i_mount;
1230         struct xfs_trans        *tp;
1231         int                     error;
1232         xfs_fileoff_t           next_fsb = XFS_B_TO_FSB(mp, offset + len);
1233         xfs_fileoff_t           shift_fsb = XFS_B_TO_FSB(mp, len);
1234         uint                    resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
1235         bool                    done = false;
1236 
1237         ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
1238         ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
1239 
1240         trace_xfs_collapse_file_space(ip);
1241 
1242         error = xfs_free_file_space(ip, offset, len);
1243         if (error)
1244                 return error;
1245 
1246         error = xfs_prepare_shift(ip, offset);
1247         if (error)
1248                 return error;
1249 
1250         while (!error && !done) {
1251                 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0,
1252                                         &tp);
1253                 if (error)
1254                         break;
1255 
1256                 xfs_ilock(ip, XFS_ILOCK_EXCL);
1257                 error = xfs_trans_reserve_quota(tp, mp, ip->i_udquot,
1258                                 ip->i_gdquot, ip->i_pdquot, resblks, 0,
1259                                 XFS_QMOPT_RES_REGBLKS);
1260                 if (error)
1261                         goto out_trans_cancel;
1262                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
1263 
1264                 error = xfs_bmap_collapse_extents(tp, ip, &next_fsb, shift_fsb,
1265                                 &done);
1266                 if (error)
1267                         goto out_trans_cancel;
1268 
1269                 error = xfs_trans_commit(tp);
1270         }
1271 
1272         return error;
1273 
1274 out_trans_cancel:
1275         xfs_trans_cancel(tp);
1276         return error;
1277 }
1278 
1279 /*
1280  * xfs_insert_file_space()
1281  *      This routine create hole space by shifting extents for the given file.
1282  *      The first thing we do is to sync dirty data and invalidate page cache
1283  *      over the region on which insert range is working. And split an extent
1284  *      to two extents at given offset by calling xfs_bmap_split_extent.
1285  *      And shift all extent records which are laying between [offset,
1286  *      last allocated extent] to the right to reserve hole range.
1287  * RETURNS:
1288  *      0 on success
1289  *      errno on error
1290  */
1291 int
1292 xfs_insert_file_space(
1293         struct xfs_inode        *ip,
1294         loff_t                  offset,
1295         loff_t                  len)
1296 {
1297         struct xfs_mount        *mp = ip->i_mount;
1298         struct xfs_trans        *tp;
1299         int                     error;
1300         xfs_fileoff_t           stop_fsb = XFS_B_TO_FSB(mp, offset);
1301         xfs_fileoff_t           next_fsb = NULLFSBLOCK;
1302         xfs_fileoff_t           shift_fsb = XFS_B_TO_FSB(mp, len);
1303         bool                    done = false;
1304 
1305         ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
1306         ASSERT(xfs_isilocked(ip, XFS_MMAPLOCK_EXCL));
1307 
1308         trace_xfs_insert_file_space(ip);
1309 
1310         error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
1311         if (error)
1312                 return error;
1313 
1314         error = xfs_prepare_shift(ip, offset);
1315         if (error)
1316                 return error;
1317 
1318         /*
1319          * The extent shifting code works on extent granularity. So, if stop_fsb
1320          * is not the starting block of extent, we need to split the extent at
1321          * stop_fsb.
1322          */
1323         error = xfs_bmap_split_extent(ip, stop_fsb);
1324         if (error)
1325                 return error;
1326 
1327         while (!error && !done) {
1328                 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0,
1329                                         &tp);
1330                 if (error)
1331                         break;
1332 
1333                 xfs_ilock(ip, XFS_ILOCK_EXCL);
1334                 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
1335                 error = xfs_bmap_insert_extents(tp, ip, &next_fsb, shift_fsb,
1336                                 &done, stop_fsb);
1337                 if (error)
1338                         goto out_trans_cancel;
1339 
1340                 error = xfs_trans_commit(tp);
1341         }
1342 
1343         return error;
1344 
1345 out_trans_cancel:
1346         xfs_trans_cancel(tp);
1347         return error;
1348 }
1349 
1350 /*
1351  * We need to check that the format of the data fork in the temporary inode is
1352  * valid for the target inode before doing the swap. This is not a problem with
1353  * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
1354  * data fork depending on the space the attribute fork is taking so we can get
1355  * invalid formats on the target inode.
1356  *
1357  * E.g. target has space for 7 extents in extent format, temp inode only has
1358  * space for 6.  If we defragment down to 7 extents, then the tmp format is a
1359  * btree, but when swapped it needs to be in extent format. Hence we can't just
1360  * blindly swap data forks on attr2 filesystems.
1361  *
1362  * Note that we check the swap in both directions so that we don't end up with
1363  * a corrupt temporary inode, either.
1364  *
1365  * Note that fixing the way xfs_fsr sets up the attribute fork in the source
1366  * inode will prevent this situation from occurring, so all we do here is
1367  * reject and log the attempt. basically we are putting the responsibility on
1368  * userspace to get this right.
1369  */
1370 static int
1371 xfs_swap_extents_check_format(
1372         struct xfs_inode        *ip,    /* target inode */
1373         struct xfs_inode        *tip)   /* tmp inode */
1374 {
1375 
1376         /* Should never get a local format */
1377         if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL ||
1378             tip->i_d.di_format == XFS_DINODE_FMT_LOCAL)
1379                 return -EINVAL;
1380 
1381         /*
1382          * if the target inode has less extents that then temporary inode then
1383          * why did userspace call us?
1384          */
1385         if (ip->i_d.di_nextents < tip->i_d.di_nextents)
1386                 return -EINVAL;
1387 
1388         /*
1389          * If we have to use the (expensive) rmap swap method, we can
1390          * handle any number of extents and any format.
1391          */
1392         if (xfs_sb_version_hasrmapbt(&ip->i_mount->m_sb))
1393                 return 0;
1394 
1395         /*
1396          * if the target inode is in extent form and the temp inode is in btree
1397          * form then we will end up with the target inode in the wrong format
1398          * as we already know there are less extents in the temp inode.
1399          */
1400         if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
1401             tip->i_d.di_format == XFS_DINODE_FMT_BTREE)
1402                 return -EINVAL;
1403 
1404         /* Check temp in extent form to max in target */
1405         if (tip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
1406             XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) >
1407                         XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1408                 return -EINVAL;
1409 
1410         /* Check target in extent form to max in temp */
1411         if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
1412             XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) >
1413                         XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1414                 return -EINVAL;
1415 
1416         /*
1417          * If we are in a btree format, check that the temp root block will fit
1418          * in the target and that it has enough extents to be in btree format
1419          * in the target.
1420          *
1421          * Note that we have to be careful to allow btree->extent conversions
1422          * (a common defrag case) which will occur when the temp inode is in
1423          * extent format...
1424          */
1425         if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
1426                 if (XFS_IFORK_Q(ip) &&
1427                     XFS_BMAP_BMDR_SPACE(tip->i_df.if_broot) > XFS_IFORK_BOFF(ip))
1428                         return -EINVAL;
1429                 if (XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <=
1430                     XFS_IFORK_MAXEXT(ip, XFS_DATA_FORK))
1431                         return -EINVAL;
1432         }
1433 
1434         /* Reciprocal target->temp btree format checks */
1435         if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE) {
1436                 if (XFS_IFORK_Q(tip) &&
1437                     XFS_BMAP_BMDR_SPACE(ip->i_df.if_broot) > XFS_IFORK_BOFF(tip))
1438                         return -EINVAL;
1439                 if (XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <=
1440                     XFS_IFORK_MAXEXT(tip, XFS_DATA_FORK))
1441                         return -EINVAL;
1442         }
1443 
1444         return 0;
1445 }
1446 
1447 static int
1448 xfs_swap_extent_flush(
1449         struct xfs_inode        *ip)
1450 {
1451         int     error;
1452 
1453         error = filemap_write_and_wait(VFS_I(ip)->i_mapping);
1454         if (error)
1455                 return error;
1456         truncate_pagecache_range(VFS_I(ip), 0, -1);
1457 
1458         /* Verify O_DIRECT for ftmp */
1459         if (VFS_I(ip)->i_mapping->nrpages)
1460                 return -EINVAL;
1461         return 0;
1462 }
1463 
1464 /*
1465  * Move extents from one file to another, when rmap is enabled.
1466  */
1467 STATIC int
1468 xfs_swap_extent_rmap(
1469         struct xfs_trans                **tpp,
1470         struct xfs_inode                *ip,
1471         struct xfs_inode                *tip)
1472 {
1473         struct xfs_trans                *tp = *tpp;
1474         struct xfs_bmbt_irec            irec;
1475         struct xfs_bmbt_irec            uirec;
1476         struct xfs_bmbt_irec            tirec;
1477         xfs_fileoff_t                   offset_fsb;
1478         xfs_fileoff_t                   end_fsb;
1479         xfs_filblks_t                   count_fsb;
1480         int                             error;
1481         xfs_filblks_t                   ilen;
1482         xfs_filblks_t                   rlen;
1483         int                             nimaps;
1484         uint64_t                        tip_flags2;
1485 
1486         /*
1487          * If the source file has shared blocks, we must flag the donor
1488          * file as having shared blocks so that we get the shared-block
1489          * rmap functions when we go to fix up the rmaps.  The flags
1490          * will be switch for reals later.
1491          */
1492         tip_flags2 = tip->i_d.di_flags2;
1493         if (ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK)
1494                 tip->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK;
1495 
1496         offset_fsb = 0;
1497         end_fsb = XFS_B_TO_FSB(ip->i_mount, i_size_read(VFS_I(ip)));
1498         count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb);
1499 
1500         while (count_fsb) {
1501                 /* Read extent from the donor file */
1502                 nimaps = 1;
1503                 error = xfs_bmapi_read(tip, offset_fsb, count_fsb, &tirec,
1504                                 &nimaps, 0);
1505                 if (error)
1506                         goto out;
1507                 ASSERT(nimaps == 1);
1508                 ASSERT(tirec.br_startblock != DELAYSTARTBLOCK);
1509 
1510                 trace_xfs_swap_extent_rmap_remap(tip, &tirec);
1511                 ilen = tirec.br_blockcount;
1512 
1513                 /* Unmap the old blocks in the source file. */
1514                 while (tirec.br_blockcount) {
1515                         ASSERT(tp->t_firstblock == NULLFSBLOCK);
1516                         trace_xfs_swap_extent_rmap_remap_piece(tip, &tirec);
1517 
1518                         /* Read extent from the source file */
1519                         nimaps = 1;
1520                         error = xfs_bmapi_read(ip, tirec.br_startoff,
1521                                         tirec.br_blockcount, &irec,
1522                                         &nimaps, 0);
1523                         if (error)
1524                                 goto out;
1525                         ASSERT(nimaps == 1);
1526                         ASSERT(tirec.br_startoff == irec.br_startoff);
1527                         trace_xfs_swap_extent_rmap_remap_piece(ip, &irec);
1528 
1529                         /* Trim the extent. */
1530                         uirec = tirec;
1531                         uirec.br_blockcount = rlen = min_t(xfs_filblks_t,
1532                                         tirec.br_blockcount,
1533                                         irec.br_blockcount);
1534                         trace_xfs_swap_extent_rmap_remap_piece(tip, &uirec);
1535 
1536                         /* Remove the mapping from the donor file. */
1537                         xfs_bmap_unmap_extent(tp, tip, &uirec);
1538 
1539                         /* Remove the mapping from the source file. */
1540                         xfs_bmap_unmap_extent(tp, ip, &irec);
1541 
1542                         /* Map the donor file's blocks into the source file. */
1543                         xfs_bmap_map_extent(tp, ip, &uirec);
1544 
1545                         /* Map the source file's blocks into the donor file. */
1546                         xfs_bmap_map_extent(tp, tip, &irec);
1547 
1548                         error = xfs_defer_finish(tpp);
1549                         tp = *tpp;
1550                         if (error)
1551                                 goto out;
1552 
1553                         tirec.br_startoff += rlen;
1554                         if (tirec.br_startblock != HOLESTARTBLOCK &&
1555                             tirec.br_startblock != DELAYSTARTBLOCK)
1556                                 tirec.br_startblock += rlen;
1557                         tirec.br_blockcount -= rlen;
1558                 }
1559 
1560                 /* Roll on... */
1561                 count_fsb -= ilen;
1562                 offset_fsb += ilen;
1563         }
1564 
1565         tip->i_d.di_flags2 = tip_flags2;
1566         return 0;
1567 
1568 out:
1569         trace_xfs_swap_extent_rmap_error(ip, error, _RET_IP_);
1570         tip->i_d.di_flags2 = tip_flags2;
1571         return error;
1572 }
1573 
1574 /* Swap the extents of two files by swapping data forks. */
1575 STATIC int
1576 xfs_swap_extent_forks(
1577         struct xfs_trans        *tp,
1578         struct xfs_inode        *ip,
1579         struct xfs_inode        *tip,
1580         int                     *src_log_flags,
1581         int                     *target_log_flags)
1582 {
1583         xfs_filblks_t           aforkblks = 0;
1584         xfs_filblks_t           taforkblks = 0;
1585         xfs_extnum_t            junk;
1586         uint64_t                tmp;
1587         int                     error;
1588 
1589         /*
1590          * Count the number of extended attribute blocks
1591          */
1592         if ( ((XFS_IFORK_Q(ip) != 0) && (ip->i_d.di_anextents > 0)) &&
1593              (ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
1594                 error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &junk,
1595                                 &aforkblks);
1596                 if (error)
1597                         return error;
1598         }
1599         if ( ((XFS_IFORK_Q(tip) != 0) && (tip->i_d.di_anextents > 0)) &&
1600              (tip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
1601                 error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK, &junk,
1602                                 &taforkblks);
1603                 if (error)
1604                         return error;
1605         }
1606 
1607         /*
1608          * Btree format (v3) inodes have the inode number stamped in the bmbt
1609          * block headers. We can't start changing the bmbt blocks until the
1610          * inode owner change is logged so recovery does the right thing in the
1611          * event of a crash. Set the owner change log flags now and leave the
1612          * bmbt scan as the last step.
1613          */
1614         if (ip->i_d.di_version == 3 &&
1615             ip->i_d.di_format == XFS_DINODE_FMT_BTREE)
1616                 (*target_log_flags) |= XFS_ILOG_DOWNER;
1617         if (tip->i_d.di_version == 3 &&
1618             tip->i_d.di_format == XFS_DINODE_FMT_BTREE)
1619                 (*src_log_flags) |= XFS_ILOG_DOWNER;
1620 
1621         /*
1622          * Swap the data forks of the inodes
1623          */
1624         swap(ip->i_df, tip->i_df);
1625 
1626         /*
1627          * Fix the on-disk inode values
1628          */
1629         tmp = (uint64_t)ip->i_d.di_nblocks;
1630         ip->i_d.di_nblocks = tip->i_d.di_nblocks - taforkblks + aforkblks;
1631         tip->i_d.di_nblocks = tmp + taforkblks - aforkblks;
1632 
1633         swap(ip->i_d.di_nextents, tip->i_d.di_nextents);
1634         swap(ip->i_d.di_format, tip->i_d.di_format);
1635 
1636         /*
1637          * The extents in the source inode could still contain speculative
1638          * preallocation beyond EOF (e.g. the file is open but not modified
1639          * while defrag is in progress). In that case, we need to copy over the
1640          * number of delalloc blocks the data fork in the source inode is
1641          * tracking beyond EOF so that when the fork is truncated away when the
1642          * temporary inode is unlinked we don't underrun the i_delayed_blks
1643          * counter on that inode.
1644          */
1645         ASSERT(tip->i_delayed_blks == 0);
1646         tip->i_delayed_blks = ip->i_delayed_blks;
1647         ip->i_delayed_blks = 0;
1648 
1649         switch (ip->i_d.di_format) {
1650         case XFS_DINODE_FMT_EXTENTS:
1651                 (*src_log_flags) |= XFS_ILOG_DEXT;
1652                 break;
1653         case XFS_DINODE_FMT_BTREE:
1654                 ASSERT(ip->i_d.di_version < 3 ||
1655                        (*src_log_flags & XFS_ILOG_DOWNER));
1656                 (*src_log_flags) |= XFS_ILOG_DBROOT;
1657                 break;
1658         }
1659 
1660         switch (tip->i_d.di_format) {
1661         case XFS_DINODE_FMT_EXTENTS:
1662                 (*target_log_flags) |= XFS_ILOG_DEXT;
1663                 break;
1664         case XFS_DINODE_FMT_BTREE:
1665                 (*target_log_flags) |= XFS_ILOG_DBROOT;
1666                 ASSERT(tip->i_d.di_version < 3 ||
1667                        (*target_log_flags & XFS_ILOG_DOWNER));
1668                 break;
1669         }
1670 
1671         return 0;
1672 }
1673 
1674 /*
1675  * Fix up the owners of the bmbt blocks to refer to the current inode. The
1676  * change owner scan attempts to order all modified buffers in the current
1677  * transaction. In the event of ordered buffer failure, the offending buffer is
1678  * physically logged as a fallback and the scan returns -EAGAIN. We must roll
1679  * the transaction in this case to replenish the fallback log reservation and
1680  * restart the scan. This process repeats until the scan completes.
1681  */
1682 static int
1683 xfs_swap_change_owner(
1684         struct xfs_trans        **tpp,
1685         struct xfs_inode        *ip,
1686         struct xfs_inode        *tmpip)
1687 {
1688         int                     error;
1689         struct xfs_trans        *tp = *tpp;
1690 
1691         do {
1692                 error = xfs_bmbt_change_owner(tp, ip, XFS_DATA_FORK, ip->i_ino,
1693                                               NULL);
1694                 /* success or fatal error */
1695                 if (error != -EAGAIN)
1696                         break;
1697 
1698                 error = xfs_trans_roll(tpp);
1699                 if (error)
1700                         break;
1701                 tp = *tpp;
1702 
1703                 /*
1704                  * Redirty both inodes so they can relog and keep the log tail
1705                  * moving forward.
1706                  */
1707                 xfs_trans_ijoin(tp, ip, 0);
1708                 xfs_trans_ijoin(tp, tmpip, 0);
1709                 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
1710                 xfs_trans_log_inode(tp, tmpip, XFS_ILOG_CORE);
1711         } while (true);
1712 
1713         return error;
1714 }
1715 
1716 int
1717 xfs_swap_extents(
1718         struct xfs_inode        *ip,    /* target inode */
1719         struct xfs_inode        *tip,   /* tmp inode */
1720         struct xfs_swapext      *sxp)
1721 {
1722         struct xfs_mount        *mp = ip->i_mount;
1723         struct xfs_trans        *tp;
1724         struct xfs_bstat        *sbp = &sxp->sx_stat;
1725         int                     src_log_flags, target_log_flags;
1726         int                     error = 0;
1727         int                     lock_flags;
1728         uint64_t                f;
1729         int                     resblks = 0;
1730 
1731         /*
1732          * Lock the inodes against other IO, page faults and truncate to
1733          * begin with.  Then we can ensure the inodes are flushed and have no
1734          * page cache safely. Once we have done this we can take the ilocks and
1735          * do the rest of the checks.
1736          */
1737         lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1738         lock_flags = XFS_MMAPLOCK_EXCL;
1739         xfs_lock_two_inodes(ip, XFS_MMAPLOCK_EXCL, tip, XFS_MMAPLOCK_EXCL);
1740 
1741         /* Verify that both files have the same format */
1742         if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
1743                 error = -EINVAL;
1744                 goto out_unlock;
1745         }
1746 
1747         /* Verify both files are either real-time or non-realtime */
1748         if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {
1749                 error = -EINVAL;
1750                 goto out_unlock;
1751         }
1752 
1753         error = xfs_swap_extent_flush(ip);
1754         if (error)
1755                 goto out_unlock;
1756         error = xfs_swap_extent_flush(tip);
1757         if (error)
1758                 goto out_unlock;
1759 
1760         if (xfs_inode_has_cow_data(tip)) {
1761                 error = xfs_reflink_cancel_cow_range(tip, 0, NULLFILEOFF, true);
1762                 if (error)
1763                         return error;
1764         }
1765 
1766         /*
1767          * Extent "swapping" with rmap requires a permanent reservation and
1768          * a block reservation because it's really just a remap operation
1769          * performed with log redo items!
1770          */
1771         if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
1772                 int             w       = XFS_DATA_FORK;
1773                 uint32_t        ipnext  = XFS_IFORK_NEXTENTS(ip, w);
1774                 uint32_t        tipnext = XFS_IFORK_NEXTENTS(tip, w);
1775 
1776                 /*
1777                  * Conceptually this shouldn't affect the shape of either bmbt,
1778                  * but since we atomically move extents one by one, we reserve
1779                  * enough space to rebuild both trees.
1780                  */
1781                 resblks = XFS_SWAP_RMAP_SPACE_RES(mp, ipnext, w);
1782                 resblks +=  XFS_SWAP_RMAP_SPACE_RES(mp, tipnext, w);
1783 
1784                 /*
1785                  * Handle the corner case where either inode might straddle the
1786                  * btree format boundary. If so, the inode could bounce between
1787                  * btree <-> extent format on unmap -> remap cycles, freeing and
1788                  * allocating a bmapbt block each time.
1789                  */
1790                 if (ipnext == (XFS_IFORK_MAXEXT(ip, w) + 1))
1791                         resblks += XFS_IFORK_MAXEXT(ip, w);
1792                 if (tipnext == (XFS_IFORK_MAXEXT(tip, w) + 1))
1793                         resblks += XFS_IFORK_MAXEXT(tip, w);
1794         }
1795         error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp);
1796         if (error)
1797                 goto out_unlock;
1798 
1799         /*
1800          * Lock and join the inodes to the tansaction so that transaction commit
1801          * or cancel will unlock the inodes from this point onwards.
1802          */
1803         xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
1804         lock_flags |= XFS_ILOCK_EXCL;
1805         xfs_trans_ijoin(tp, ip, 0);
1806         xfs_trans_ijoin(tp, tip, 0);
1807 
1808 
1809         /* Verify all data are being swapped */
1810         if (sxp->sx_offset != 0 ||
1811             sxp->sx_length != ip->i_d.di_size ||
1812             sxp->sx_length != tip->i_d.di_size) {
1813                 error = -EFAULT;
1814                 goto out_trans_cancel;
1815         }
1816 
1817         trace_xfs_swap_extent_before(ip, 0);
1818         trace_xfs_swap_extent_before(tip, 1);
1819 
1820         /* check inode formats now that data is flushed */
1821         error = xfs_swap_extents_check_format(ip, tip);
1822         if (error) {
1823                 xfs_notice(mp,
1824                     "%s: inode 0x%llx format is incompatible for exchanging.",
1825                                 __func__, ip->i_ino);
1826                 goto out_trans_cancel;
1827         }
1828 
1829         /*
1830          * Compare the current change & modify times with that
1831          * passed in.  If they differ, we abort this swap.
1832          * This is the mechanism used to ensure the calling
1833          * process that the file was not changed out from
1834          * under it.
1835          */
1836         if ((sbp->bs_ctime.tv_sec != VFS_I(ip)->i_ctime.tv_sec) ||
1837             (sbp->bs_ctime.tv_nsec != VFS_I(ip)->i_ctime.tv_nsec) ||
1838             (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
1839             (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
1840                 error = -EBUSY;
1841                 goto out_trans_cancel;
1842         }
1843 
1844         /*
1845          * Note the trickiness in setting the log flags - we set the owner log
1846          * flag on the opposite inode (i.e. the inode we are setting the new
1847          * owner to be) because once we swap the forks and log that, log
1848          * recovery is going to see the fork as owned by the swapped inode,
1849          * not the pre-swapped inodes.
1850          */
1851         src_log_flags = XFS_ILOG_CORE;
1852         target_log_flags = XFS_ILOG_CORE;
1853 
1854         if (xfs_sb_version_hasrmapbt(&mp->m_sb))
1855                 error = xfs_swap_extent_rmap(&tp, ip, tip);
1856         else
1857                 error = xfs_swap_extent_forks(tp, ip, tip, &src_log_flags,
1858                                 &target_log_flags);
1859         if (error)
1860                 goto out_trans_cancel;
1861 
1862         /* Do we have to swap reflink flags? */
1863         if ((ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK) ^
1864             (tip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK)) {
1865                 f = ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK;
1866                 ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
1867                 ip->i_d.di_flags2 |= tip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK;
1868                 tip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK;
1869                 tip->i_d.di_flags2 |= f & XFS_DIFLAG2_REFLINK;
1870         }
1871 
1872         /* Swap the cow forks. */
1873         if (xfs_sb_version_hasreflink(&mp->m_sb)) {
1874                 ASSERT(ip->i_cformat == XFS_DINODE_FMT_EXTENTS);
1875                 ASSERT(tip->i_cformat == XFS_DINODE_FMT_EXTENTS);
1876 
1877                 swap(ip->i_cnextents, tip->i_cnextents);
1878                 swap(ip->i_cowfp, tip->i_cowfp);
1879 
1880                 if (ip->i_cowfp && ip->i_cowfp->if_bytes)
1881                         xfs_inode_set_cowblocks_tag(ip);
1882                 else
1883                         xfs_inode_clear_cowblocks_tag(ip);
1884                 if (tip->i_cowfp && tip->i_cowfp->if_bytes)
1885                         xfs_inode_set_cowblocks_tag(tip);
1886                 else
1887                         xfs_inode_clear_cowblocks_tag(tip);
1888         }
1889 
1890         xfs_trans_log_inode(tp, ip,  src_log_flags);
1891         xfs_trans_log_inode(tp, tip, target_log_flags);
1892 
1893         /*
1894          * The extent forks have been swapped, but crc=1,rmapbt=0 filesystems
1895          * have inode number owner values in the bmbt blocks that still refer to
1896          * the old inode. Scan each bmbt to fix up the owner values with the
1897          * inode number of the current inode.
1898          */
1899         if (src_log_flags & XFS_ILOG_DOWNER) {
1900                 error = xfs_swap_change_owner(&tp, ip, tip);
1901                 if (error)
1902                         goto out_trans_cancel;
1903         }
1904         if (target_log_flags & XFS_ILOG_DOWNER) {
1905                 error = xfs_swap_change_owner(&tp, tip, ip);
1906                 if (error)
1907                         goto out_trans_cancel;
1908         }
1909 
1910         /*
1911          * If this is a synchronous mount, make sure that the
1912          * transaction goes to disk before returning to the user.
1913          */
1914         if (mp->m_flags & XFS_MOUNT_WSYNC)
1915                 xfs_trans_set_sync(tp);
1916 
1917         error = xfs_trans_commit(tp);
1918 
1919         trace_xfs_swap_extent_after(ip, 0);
1920         trace_xfs_swap_extent_after(tip, 1);
1921 
1922 out_unlock:
1923         xfs_iunlock(ip, lock_flags);
1924         xfs_iunlock(tip, lock_flags);
1925         unlock_two_nondirectories(VFS_I(ip), VFS_I(tip));
1926         return error;
1927 
1928 out_trans_cancel:
1929         xfs_trans_cancel(tp);
1930         goto out_unlock;
1931 }