ext2: Zero our b_size in ext2_quota_read()

ext2_quota_read() doesn't initialize tmp_bh.b_size before calling
ext2_get_block() where we access it. Since it is a local variable it
might contain some garbage. Make sure it is filled with reasonable
value before passing.
Signed-off-by: NManish Katiyar <mkatiyar@gmail.com>
Signed-off-by: NJan Kara <jack@suse.cz>

fs/ext2/super.c

@@ -1331,6 +1331,7 @@ static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
 				sb->s_blocksize - offset : toread;
 
 		tmp_bh.b_state = 0;
+		tmp_bh.b_size = sb->s_blocksize;
 		err = ext2_get_block(inode, blk, &tmp_bh, 0);
 		if (err < 0)
 			return err;