[XFS] Use the right offset when ensuring a delayed allocate conversion has covered the offset originally requested. Can cause data corruption when multiple processes are performing writeout on different areas of the same file. Quite difficult to hit though.

SGI Modid: xfs-linux:xfs-kern:22377a

Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Christoph Hellwig <hch@sgi.com>
.

1 files changed, 11 insertions, 9 deletions

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 3826e8f0e28a..b291a2b53579 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -308,7 +308,8 @@ phase2:
                         break;
                 }
 
-                error = XFS_IOMAP_WRITE_ALLOCATE(mp, io, &imap, &nimaps);
+                error = XFS_IOMAP_WRITE_ALLOCATE(mp, io, offset, count,
+                                                 &imap, &nimaps);
                 break;
         case BMAPI_UNWRITTEN:
                 lockmode = 0;
@@ -746,6 +747,8 @@ write_map:
 int
 xfs_iomap_write_allocate(
         xfs_inode_t     *ip,
+        loff_t          offset,
+        size_t          count,
         xfs_bmbt_irec_t *map,
         int             *retmap)
 {
@@ -770,9 +773,9 @@ xfs_iomap_write_allocate(
         if ((error = XFS_QM_DQATTACH(mp, ip, 0)))
                 return XFS_ERROR(error);
 
-        offset_fsb = map->br_startoff;
+        offset_fsb = XFS_B_TO_FSBT(mp, offset);
         count_fsb = map->br_blockcount;
-        map_start_fsb = offset_fsb;
+        map_start_fsb = map->br_startoff;
 
         XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
 
@@ -868,9 +871,9 @@ xfs_iomap_write_allocate(
                                         imap[i].br_startoff,
                                         imap[i].br_blockcount,imap[i].br_state);
                         }
-                        if ((map->br_startoff >= imap[i].br_startoff) &&
-                            (map->br_startoff < (imap[i].br_startoff +
-                                                 imap[i].br_blockcount))) {
+                        if ((offset_fsb >= imap[i].br_startoff) &&
+                            (offset_fsb < (imap[i].br_startoff +
+                                           imap[i].br_blockcount))) {
                                 *map = imap[i];
                                 *retmap = 1;
                                 XFS_STATS_INC(xs_xstrat_quick);
@@ -883,9 +886,8 @@ xfs_iomap_write_allocate(
                  * file, just surrounding data, try again.
                  */
                 nimaps--;
-                offset_fsb = imap[nimaps].br_startoff +
-                             imap[nimaps].br_blockcount;
-                map_start_fsb = offset_fsb;
+                map_start_fsb = imap[nimaps].br_startoff +
+                                imap[nimaps].br_blockcount;
         }
 
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