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

[Luis Henriques]

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-3.11.y-queue branch of the 3.11.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-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From c72e9d1964edc32ca535ae324e2ab81f3fcf7e66 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: Luis Henriques <luis.henriques 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 2885349..20d6697 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