From e1c9af1edac26b1d05492ccb1e5fb1dbe59cc649 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Tue, 9 Oct 2012 14:50:52 +1100
Subject: [PATCH] --- yaml --- r: 335455 b: refs/heads/master c:
 eaef854335ce09956e930fe4a193327417edc6c9 h: refs/heads/master i:   335453:
 1c44fcbc377d5c027321d00805bbd54762960e98   335451:
 d7c5ccae3740f913ed14c65433160a65f1370a85   335447:
 cd8d764780288e70fe341974be3b4d32c3e71ed4   335439:
 b4547d940605b213eedf145eb2d28a81e7134bd0   335423:
 5bdfeff28e87479602c6f8a86c050ec2b5fc45ac v: v3

---
 [refs]                   |  2 +-
 trunk/fs/xfs/xfs_fsops.c | 21 +++++++++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 3e863174b577..7610b0c4d77e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1f3c785c3adb7d2b109ec7c8f10081d1294b03d3
+refs/heads/master: eaef854335ce09956e930fe4a193327417edc6c9
diff --git a/trunk/fs/xfs/xfs_fsops.c b/trunk/fs/xfs/xfs_fsops.c
index c25b094efbf7..4beaede43277 100644
--- a/trunk/fs/xfs/xfs_fsops.c
+++ b/trunk/fs/xfs/xfs_fsops.c
@@ -399,9 +399,26 @@ xfs_growfs_data_private(
 
 	/* update secondary superblocks. */
 	for (agno = 1; agno < nagcount; agno++) {
-		error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
+		error = 0;
+		/*
+		 * new secondary superblocks need to be zeroed, not read from
+		 * disk as the contents of the new area we are growing into is
+		 * completely unknown.
+		 */
+		if (agno < oagcount) {
+			error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
 				  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
 				  XFS_FSS_TO_BB(mp, 1), 0, &bp);
+		} else {
+			bp = xfs_trans_get_buf(NULL, mp->m_ddev_targp,
+				  XFS_AGB_TO_DADDR(mp, agno, XFS_SB_BLOCK(mp)),
+				  XFS_FSS_TO_BB(mp, 1), 0);
+			if (bp)
+				xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
+			else
+				error = ENOMEM;
+		}
+
 		if (error) {
 			xfs_warn(mp,
 		"error %d reading secondary superblock for ag %d",
@@ -423,7 +440,7 @@ xfs_growfs_data_private(
 			break; /* no point in continuing */
 		}
 	}
-	return 0;
+	return error;
 
  error0:
 	xfs_trans_cancel(tp, XFS_TRANS_ABORT);