[PATCH 3.2 35/79] ext2: Fix oops in ext2_get_block() called from ext2_quota_write()

[Ben Hutchings]

3.2.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@xxxxxxx>

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@xxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reported-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 fs/ext2/super.c | 1 +
 1 file changed, 1 insertion(+)

--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1448,6 +1448,7 @@ static ssize_t ext2_quota_write(struct s
 				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;

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