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From: Dave Chinner <david@fromorbit.com>
To: stable@kernel.org
Cc: xfs@oss.sgi.com
Subject: [PATCH 13/19] xfs: fix stale inode flush avoidance
Date: Fri, 12 Mar 2010 09:42:11 +1100	[thread overview]
Message-ID: <1268347337-7160-14-git-send-email-david@fromorbit.com> (raw)
In-Reply-To: <1268347337-7160-1-git-send-email-david@fromorbit.com>

>From 4b6a46882cca8349e8942e2650c33b11bc571c92
Date: Mon, 11 Jan 2010 11:45:21 +0000
When reclaiming stale inodes, we need to guarantee that inodes are
unpinned before returning with a "clean" status. If we don't we can
reclaim inodes that are pinned, leading to use after free in the
transaction subsystem as transactions complete.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
---
 fs/xfs/xfs_inode.c |   21 +++++++++++++++------
 1 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 13d7d21..523a1ae 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2878,13 +2878,9 @@ xfs_iflush(
 
 	/*
 	 * If the inode isn't dirty, then just release the inode flush lock and
-	 * do nothing. Treat stale inodes the same; we cannot rely on the
-	 * backing buffer remaining stale in cache for the remaining life of
-	 * the stale inode and so xfs_itobp() below may give us a buffer that
-	 * no longer contains inodes below. Doing this stale check here also
-	 * avoids forcing the log on pinned, stale inodes.
+	 * do nothing.
 	 */
-	if (xfs_inode_clean(ip) || xfs_iflags_test(ip, XFS_ISTALE)) {
+	if (xfs_inode_clean(ip)) {
 		xfs_ifunlock(ip);
 		return 0;
 	}
@@ -2908,6 +2904,19 @@ xfs_iflush(
 	xfs_iunpin_wait(ip);
 
 	/*
+	 * For stale inodes we cannot rely on the backing buffer remaining
+	 * stale in cache for the remaining life of the stale inode and so
+	 * xfs_itobp() below may give us a buffer that no longer contains
+	 * inodes below. We have to check this after ensuring the inode is
+	 * unpinned so that it is safe to reclaim the stale inode after the
+	 * flush call.
+	 */
+	if (xfs_iflags_test(ip, XFS_ISTALE)) {
+		xfs_ifunlock(ip);
+		return 0;
+	}
+
+	/*
 	 * This may have been unpinned because the filesystem is shutting
 	 * down forcibly. If that's the case we must not write this inode
 	 * to disk, because the log record didn't make it to disk!
-- 
1.6.5

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  parent reply	other threads:[~2010-03-11 22:41 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1268347337-7160-1-git-send-email-david@fromorbit.com>
2010-03-11 22:41 ` [PATCH 01/19] xfs: simplify inode teardown Dave Chinner
2010-03-11 22:42 ` [PATCH 02/19] xfs: fix mmap_sem/iolock inversion in xfs_free_eofblocks Dave Chinner
2010-03-11 22:42 ` [PATCH 03/19] xfs: I/O completion handlers must use NOFS allocations Dave Chinner
2010-03-11 22:42 ` [PATCH 04/19] xfs: Wrapped journal record corruption on read at recovery Dave Chinner
2010-03-11 22:42 ` [PATCH 05/19] xfs: Fix error return for fallocate() on XFS Dave Chinner
2010-03-11 22:42 ` [PATCH 06/19] xfs: check for not fully initialized inodes in xfs_ireclaim Dave Chinner
2010-03-11 22:42 ` [PATCH 07/19] xfs: fix timestamp handling in xfs_setattr Dave Chinner
2010-03-11 22:42 ` [PATCH 08/19] xfs: Don't flush stale inodes Dave Chinner
2010-03-11 22:42 ` [PATCH 09/19] xfs: Ensure we force all busy extents in range to disk Dave Chinner
2010-03-11 22:42 ` [PATCH 10/19] xfs: reclaim inodes under a write lock Dave Chinner
2010-03-11 22:42 ` [PATCH 11/19] xfs: Avoid inodes in reclaim when flushing from inode cache Dave Chinner
2010-03-11 22:42 ` [PATCH 12/19] xfs: reclaim all inodes by background tree walks Dave Chinner
2010-03-11 22:42 ` Dave Chinner [this message]
2010-03-11 22:42 ` [PATCH 14/19] xfs: xfs_swap_extents needs to handle dynamic fork offsets Dave Chinner
2010-03-11 22:42 ` [PATCH 15/19] xfs: quota limit statvfs available blocks Dave Chinner
2010-03-11 22:42 ` [PATCH 16/19] xfs: don't hold onto reserved blocks on remount,ro Dave Chinner
2010-03-11 22:42 ` [PATCH 17/19] xfs: remove invalid barrier optimization from xfs_fsync Dave Chinner
2010-03-11 22:42 ` [PATCH 18/19] xfs: Non-blocking inode locking in IO completion Dave Chinner

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