gfs2: Always check inode size of inline inodes

commit 70376c7ff31221f1d21db5611d8209e677781d3a upstream.

Check if the inode size of stuffed (inline) inodes is within the allowed
range when reading inodes from disk (gfs2_dinode_in()).  This prevents
us from on-disk corruption.

The two checks in stuffed_readpage() and gfs2_unstuffer_page() that just
truncate inline data to the maximum allowed size don't actually make
sense, and they can be removed now as well.

Reported-by:  <syzbot+7bb81dfa9cda07d9cd9d@syzkaller.appspotmail.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
[pchelkin@ispras.ru: adjust the inode variable inside gfs2_dinode_in with
the format used before upstream commit 7db354444ad8 ("gfs2: Cosmetic
gfs2_dinode_{in,out} cleanup")]
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>