linux-ext4 - [PATCH] e2fsck: When restarting fsck on account of MMP, zero ctx->fs after fs is freed

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Message-ID: <20110930194005.GT12086@tux1.beaverton.ibm.com>
Date:	Fri, 30 Sep 2011 12:40:05 -0700
From:	"Darrick J. Wong" <djwong@...ibm.com>
To:	"Theodore Ts'o" <tytso@....edu>
Cc:	linux-ext4 <linux-ext4@...r.kernel.org>
Subject: [PATCH] e2fsck: When restarting fsck on account of MMP, zero
	ctx->fs after fs is freed

If MMP is enabled and e2fsck determines that it needs to restart itself on
account of various MMP conditions, it will close the current fs and jump back
to the start of fs checking.  However, closing fs also frees it, which means
that we need to set ctx->fs to NULL to prevent subsequent open code from
accessing the old deleted pointer.

(This fix came up while testing the metadata checksumming patchset)

Signed-off-by: Darrick J. Wong <djwong@...ibm.com>
---

 e2fsck/unix.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index f980962..37cfb00 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -1351,6 +1351,7 @@ failure:
 	  * Restart in order to reopen fs but this time start mmp.
 	  */
 	if (flags & EXT2_FLAG_SKIP_MMP) {
+		ctx->fs = NULL;
 		ext2fs_close(fs);
 		flags &= ~EXT2_FLAG_SKIP_MMP;
 		goto restart;
--
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