From d7a2b53c8e0a7a9fa1d553c91eb253e72d17ef5e 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: 339388 b: refs/heads/master c:
 1375cb65e87b327a8dd4f920c3e3d837fb40e9c2 h: refs/heads/master 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 47c59b102de8..d72f4316efe1 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e04426b9202bccd4cfcbc70b2fa2aeca1c86d8f5
+refs/heads/master: 1375cb65e87b327a8dd4f920c3e3d837fb40e9c2
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);