xfs: remove the truncate short cut in xfs_map_blocks

Now that we properly handle the race with truncate in the delalloc
allocator there is no need to short cut this exceptional case earlier
on.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 42017ec..a6abb71 100644 (file)
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -420,26 +420,6 @@ xfs_map_blocks(
                xfs_iunlock(ip, XFS_ILOCK_SHARED);
 
                wpc->fork = XFS_COW_FORK;
-
-               /*
-                * Truncate can race with writeback since writeback doesn't
-                * take the iolock and truncate decreases the file size before
-                * it starts truncating the pages between new_size and old_size.
-                * Therefore, we can end up in the situation where writeback
-                * gets a CoW fork mapping but the truncate makes the mapping
-                * invalid and we end up in here trying to get a new mapping.
-                * bail out here so that we simply never get a valid mapping
-                * and so we drop the write altogether.  The page truncation
-                * will kill the contents anyway.
-                */
-               if (offset > i_size_read(inode)) {
-                       wpc->imap.br_blockcount = end_fsb - offset_fsb;
-                       wpc->imap.br_startoff = offset_fsb;
-                       wpc->imap.br_startblock = HOLESTARTBLOCK;
-                       wpc->imap.br_state = XFS_EXT_NORM;
-                       return 0;
-               }
-
                goto allocate_blocks;
        }