This is a note to let you know that I've just added the patch titled
ext2: Fix fs corruption in ext2_get_xip_mem()
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext2-fix-fs-corruption-in-ext2_get_xip_mem.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7ba3ec5749ddb61f79f7be17b5fd7720eebc52de Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@xxxxxxx>
Date: Tue, 5 Nov 2013 01:15:38 +0100
Subject: ext2: Fix fs corruption in ext2_get_xip_mem()
From: Jan Kara <jack@xxxxxxx>
commit 7ba3ec5749ddb61f79f7be17b5fd7720eebc52de upstream.
Commit 8e3dffc651cb "Ext2: mark inode dirty after the function
dquot_free_block_nodirty is called" unveiled a bug in __ext2_get_block()
called from ext2_get_xip_mem(). That function called ext2_get_block()
mistakenly asking it to map 0 blocks while 1 was intended. Before the
above mentioned commit things worked out fine by luck but after that commit
we started returning that we allocated 0 blocks while we in fact
allocated 1 block and thus allocation was looping until all blocks in
the filesystem were exhausted.
Fix the problem by properly asking for one block and also add assertion
in ext2_get_blocks() to catch similar problems.
Reported-and-tested-by: Andiry Xu <andiry.xu@xxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext2/inode.c | 2 ++
fs/ext2/xip.c | 1 +
2 files changed, 3 insertions(+)
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -632,6 +632,8 @@ static int ext2_get_blocks(struct inode
int count = 0;
ext2_fsblk_t first_block = 0;
+ BUG_ON(maxblocks == 0);
+
depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
if (depth == 0)
--- a/fs/ext2/xip.c
+++ b/fs/ext2/xip.c
@@ -35,6 +35,7 @@ __ext2_get_block(struct inode *inode, pg
int rc;
memset(&tmp, 0, sizeof(struct buffer_head));
+ tmp.b_size = 1 << inode->i_blkbits;
rc = ext2_get_block(inode, pgoff, &tmp, create);
*result = tmp.b_blocknr;
Patches currently in stable-queue which might be from jack@xxxxxxx are
queue-3.10/ext2-fix-fs-corruption-in-ext2_get_xip_mem.patch
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