[XFS] Catch unwritten extent conversion errors.

On unwritten I/O completion, we fail to propagate an error when converting
the extent to a written extent. This means that the I/O silently fails.
propagate the error onto the ioend so that the inode is marked with an
error appropriately.

SGI-PV: 980084
SGI-Modid: xfs-linux-melb:xfs-kern:30826a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

fs/xfs/linux-2.6/xfs_aops.c

@@ -243,8 +243,12 @@ xfs_end_bio_unwritten(
 	size_t			size = ioend->io_size;
 
 	if (likely(!ioend->io_error)) {
-		if (!XFS_FORCED_SHUTDOWN(ip->i_mount))
-			xfs_iomap_write_unwritten(ip, offset, size);
+		if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
+			int error;
+			error = xfs_iomap_write_unwritten(ip, offset, size);
+			if (error)
+				ioend->io_error = error;
+		}
 		xfs_setfilesize(ioend);
 	}
 	xfs_destroy_ioend(ioend);