Re: [PATCH 01/11] ext4: Fix xattr shifting when expanding inodes

[Theodore Ts'o <tytso@mit.edu>]

On Wed, Aug 03, 2016 at 12:39:45PM +0200, Jan Kara wrote:
> The code in ext4_expand_extra_isize_ea() treated new_extra_isize
> argument sometimes as the desired target i_extra_isize and sometimes as
> the amount by which we need to grow current i_extra_isize. These happen
> to coincide when i_extra_isize is 0 which used to be the common case and
> so nobody noticed this until recently when we added i_projid to the
> inode and so i_extra_isize now needs to grow from 28 to 32 bytes.
> 
> The result of these bugs was that we sometimes unnecessarily decided to
> move xattrs out of inode even if there was enough space and we often
> ended up corrupting in-inode xattrs because arguments to
> ext4_xattr_shift_entries() were just wrong. This could demonstrate
> itself as BUG_ON in ext4_xattr_shift_entries() triggering.
> 
> Fix the problem by introducing new isize_diff variable and use it where
> appropriate.
> 
> CC: <stable@vger.kernel.org> # 4.4.x-
> Reported-by: Dave Chinner <david@fromorbit.com>
> Signed-off-by: Jan Kara <jack@suse.cz>

Thanks, applied.

					- Ted