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From: Dave Chinner <david@fromorbit.com>
To: xfs@oss.sgi.com
Subject: [PATCH 2/6] xfs: growfs: don't read garbage for new secondary superblocks
Date: Fri,  2 Nov 2012 11:38:40 +1100	[thread overview]
Message-ID: <1351816724-3000-3-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1351816724-3000-1-git-send-email-david@fromorbit.com>

From: Dave Chinner <dchinner@redhat.com>

When updating new secondary superblocks in a growfs operation, the
sueprblock buffer is read from the newly grown region of the
underlying device. This is not guaranteed to be zero, so violates
the underlying assumption that the unused parts of superblocks are
zero filled. Get a new buffer for these secondary superblocks to
ensure that the unused regions are zero filled correctly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_fsops.c |   21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index c25b094..4beaede 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/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);
-- 
1.7.10

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  parent reply	other threads:[~2012-11-02  0:37 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-02  0:38 [PATCH 0/6] xfs: fixes for 3.7-rc3 Dave Chinner
2012-11-02  0:38 ` [PATCH 1/6] xfs: silence uninitialised f.file warning Dave Chinner
2012-11-02 13:04   ` Christoph Hellwig
2012-11-02 21:23   ` Mark Tinguely
2012-11-02  0:38 ` Dave Chinner [this message]
2012-11-02  0:38 ` [PATCH 3/6] xfs: invalidate allocbt blocks moved to the free list Dave Chinner
2012-10-09 19:11   ` [PATCH] xfs: report projid32bit feature in geometry call Eric Sandeen
2012-10-09 19:28     ` Carlos Maiolino
2012-10-09 19:45     ` Dave Chinner
2012-10-11  0:02     ` Eric Sandeen
2012-10-30 19:43       ` Ben Myers
2012-10-30 19:44         ` Eric Sandeen
2012-11-08 16:12     ` Ben Myers
2012-11-02 21:23   ` [PATCH 3/6] xfs: invalidate allocbt blocks moved to the free list Mark Tinguely
2012-11-02  0:38 ` [PATCH 4/6] xfs: don't vmap inode cluster buffers during free Dave Chinner
2012-11-02 13:05   ` Christoph Hellwig
2012-11-02 21:24   ` Mark Tinguely
2012-11-02  0:38 ` [PATCH 5/6] xfs: fix buffer shudown reference count mismatch Dave Chinner
2012-11-02  2:43   ` Dave Chinner
2012-11-02  3:23     ` [PATCH 5/6 V2] " Dave Chinner
2012-11-02 13:17       ` Mark Tinguely
2012-11-02 13:13     ` [PATCH 5/6] " Christoph Hellwig
2012-11-02 17:10       ` Mark Tinguely
2012-11-02 23:47       ` Dave Chinner
2012-11-06 12:59         ` Christoph Hellwig
2012-11-06 19:59           ` Dave Chinner
2012-11-02  0:38 ` [PATCH 6/6] xfs: fix reading of wrapped log data Dave Chinner
2012-11-02 13:07   ` Christoph Hellwig
2012-11-02 23:51     ` Dave Chinner
2012-11-02 21:24   ` Mark Tinguely
2012-11-07 20:56 ` [PATCH 0/6] xfs: fixes for 3.7-rc3 Dave Chinner
2012-11-08 16:34   ` Ben Myers
2012-11-08 16:15 ` Ben Myers

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