[XFS] Ensure errors from xfs_bdstrat() are correctly checked.

xfsbdstrat() is declared to return an error. That is never checked because
the error is propagated by the xfs_buf_t that is passed through the
function.

Mark xfsbdstrat() as returning void and comment the prototype on the
methods needed for error checking.

SGI-PV: 980084
SGI-Modid: xfs-linux-melb:xfs-kern:30823a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Niv Sardi <xaiki@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 4e5c010..cb0c583 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -354,17 +354,15 @@
 			ASSERT(!XFS_BUF_ISASYNC(bp));
 			XFS_BUF_READ(bp);
 			xfsbdstrat(tp->t_mountp, bp);
-			xfs_iowait(bp);
-			if (XFS_BUF_GETERROR(bp) != 0) {
+			error = xfs_iowait(bp);
+			if (error) {
 				xfs_ioerror_alert("xfs_trans_read_buf", mp,
 						  bp, blkno);
-				error = XFS_BUF_GETERROR(bp);
 				xfs_buf_relse(bp);
 				/*
-				 * We can gracefully recover from most
-				 * read errors. Ones we can't are those
-				 * that happen after the transaction's
-				 * already dirty.
+				 * We can gracefully recover from most read
+				 * errors. Ones we can't are those that happen
+				 * after the transaction's already dirty.
 				 */
 				if (tp->t_flags & XFS_TRANS_DIRTY)
 					xfs_force_shutdown(tp->t_mountp,