[3.8.y.z extended stable] Patch "ext2: Fix oops in ext2_get_block() called from ext2_quota_write()" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    ext2: Fix oops in ext2_get_block() called from ext2_quota_write()

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 470aba9af6498621986835c4e63aca11501c580a Mon Sep 17 00:00:00 2001
From: Jan Kara <jack at suse.cz>
Date: Tue, 3 Dec 2013 11:20:06 +0100
Subject: ext2: Fix oops in ext2_get_block() called from ext2_quota_write()

commit df4e7ac0bb70abc97fbfd9ef09671fc084b3f9db upstream.

ext2_quota_write() doesn't properly setup bh it passes to
ext2_get_block() and thus we hit assertion BUG_ON(maxblocks == 0) in
ext2_get_blocks() (or we could actually ask for mapping arbitrary number
of blocks depending on whatever value was on stack).

Fix ext2_quota_write() to properly fill in number of blocks to map.

Reviewed-by: "Theodore Ts'o" <tytso at mit.edu>
Reviewed-by: Christoph Hellwig <hch at lst.de>
Reported-by: Christoph Hellwig <hch at infradead.org>
Signed-off-by: Jan Kara <jack at suse.cz>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/ext2/super.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index fa04d02..9d8b0ad 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1493,6 +1493,7 @@ static ssize_t ext2_quota_write(struct super_block *sb, int type,
 				sb->s_blocksize - offset : towrite;

 		tmp_bh.b_state = 0;
+		tmp_bh.b_size = sb->s_blocksize;
 		err = ext2_get_block(inode, blk, &tmp_bh, 1);
 		if (err < 0)
 			goto out;
--
1.8.3.2