[XFS] Check for dquot flush errors

xfs_qm_dqflush() can fail, but the return is not checked anywhere. Hence
we never know if we've failed to flush a dquot to disk. Propagate the
error and warn to the syslog if a flush ever fails.

SGI-PV: 980084
SGI-Modid: xfs-linux-melb:xfs-kern:30787a

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/quota/xfs_dquot_item.c b/fs/xfs/quota/xfs_dquot_item.c
index 1800e8d..3dedce1 100644
--- a/fs/xfs/quota/xfs_dquot_item.c
+++ b/fs/xfs/quota/xfs_dquot_item.c
@@ -146,6 +146,7 @@
 	xfs_dq_logitem_t	*logitem)
 {
 	xfs_dquot_t	*dqp;
+	int		error;
 
 	dqp = logitem->qli_dquot;
 
@@ -161,7 +162,11 @@
 	 * lock without sleeping, then there must not have been
 	 * anyone in the process of flushing the dquot.
 	 */
-	xfs_qm_dqflush(dqp, XFS_B_DELWRI);
+	error = xfs_qm_dqflush(dqp, XFS_QMOPT_DELWRI);
+	if (error)
+		xfs_fs_cmn_err(CE_WARN, dqp->q_mount,
+			"xfs_qm_dquot_logitem_push: push error %d on dqp %p",
+			error, dqp);
 	xfs_dqunlock(dqp);
 }