xfs: Check the return value of xfs_trans_get_buf()

Check the return value of xfs_trans_get_buf() and fail
appropriately.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Alex Elder <aelder@sgi.com>

diff --git a/fs/xfs/xfs_dquot.c b/fs/xfs/xfs_dquot.c
index 3e2ccae..0c5fe66 100644
--- a/fs/xfs/xfs_dquot.c
+++ b/fs/xfs/xfs_dquot.c
@@ -402,8 +402,11 @@
 			       dqp->q_blkno,
 			       mp->m_quotainfo->qi_dqchunklen,
 			       0);
-	if (!bp || (error = xfs_buf_geterror(bp)))
+
+	error = xfs_buf_geterror(bp);
+	if (error)
 		goto error1;
+
 	/*
 	 * Make a chunk of dquots out of this buffer and log
 	 * the entire thing.