xfs: update i_size after unwritten conversion in dio completion
Since commit d531d91d6990 ("xfs: always use unwritten extents for
direct I/O writes"), we start allocating unwritten extents for all
direct writes to allow appending aio in XFS.
But for dio writes that could extend file size we update the in-core
inode size first, then convert the unwritten extents to real
allocations at dio completion time in xfs_dio_write_end_io(). Thus a
racing direct read could see the new i_size and find the unwritten
extents first and read zeros instead of actual data, if the direct
writer also takes a shared iolock.
Fix it by updating the in-core inode size after the unwritten extent
conversion. To do this, introduce a new boolean argument to
xfs_iomap_write_unwritten() to tell if we want to update in-core
i_size or not.
Suggested-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eryu Guan <eguan@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 2917260..f18e593 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -343,7 +343,8 @@ xfs_end_io(
error = xfs_reflink_end_cow(ip, offset, size);
break;
case XFS_IO_UNWRITTEN:
- error = xfs_iomap_write_unwritten(ip, offset, size);
+ /* writeback should never update isize */
+ error = xfs_iomap_write_unwritten(ip, offset, size, false);
break;
default:
ASSERT(!xfs_ioend_is_append(ioend) || ioend->io_append_trans);