Re: [PATCH] xfs: fix inode number overflow in ifree cluster helper

[Christoph Hellwig <hch@infradead.org>]

On Thu, Apr 02, 2020 at 06:57:18AM -0400, Brian Foster wrote:
> Qian Cai reports seemingly random buffer read verifier errors during
> filesystem writeback. This was isolated to a recent patch that
> factored out some inode cluster freeing code and happened to cast an
> unsigned inode number type to a signed value. If the inode number
> value overflows, we can skip marking in-core inodes associated with
> the underlying buffer stale at the time the physical inodes are
> freed. If such an inode happens to be dirty, xfsaild will eventually
> attempt to write it back over non-inode blocks. The invalidation of
> the underlying inode buffer causes writeback to read the buffer from
> disk. This fails the read verifier (preventing eventual corruption)
> if the buffer no longer looks like an inode cluster. Analysis by
> Dave Chinner.
> 
> Fix up the helper to use the proper type for inode number values.
> 
> Fixes: 5806165a6663 ("xfs: factor inode lookup from xfs_ifree_cluster")
> Reported-by: Qian Cai <cai@lca.pw>
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> ---
> 
> Fixes the problem described here[1]. I wasn't sure if we planned on
> fixing the original patch in for-next or wanted a separate patch. Feel
> free to commit standalone or fold into the original...

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>