Re: [PATCH 5/9] xfs: reinitialise recycled VFS inode correctly

Brian Foster
2016-02-08T15:29:32Z

On Mon, Feb 08, 2016 at 03:24:17PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Now that we keep certain on-disk information in the VFS inode rather
> than in a separate XFS specific stucture, we have to be careful of
> the VFS code clearing that information when we re-initialise
> reclaimable cached inodes during lookup. If we don't do this, then
> we lose critical information from the inode and that results in
> corruption being detected.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

> fs/xfs/xfs_icache.c | 22 +++++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 7c26f86..9ca28655 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -135,6 +135,26 @@ xfs_inode_free(
> }
>
> /*
> + * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
> + * part of the structure. This is made more complex by the fact we store
> + * information about the on-disk values in the VFS inode and so we can't just
> + * overwrite it's values unconditionally. Hence we save the parameters we
> + * need to retain across reinitialisation, and rewrite them into the VFS inode
> + * after resetting it's state even if resetting fails.
> + */
> +static int
> +xfs_reinit_inode(
> + struct xfs_mount *mp,
> + struct inode *inode)
> +{
> + int error;
> +
> + error = inode_init_always(mp->m_super, inode);
> +
> + return error;
> +}
> +
> +/*
> * Check the validity of the inode we just found it the cache
> */
> static int
> @@ -208,7 +228,7 @@ xfs_iget_cache_hit(
> spin_unlock(&ip->i_flags_lock);
> rcu_read_unlock();
>
> - error = inode_init_always(mp->m_super, inode);
> + error = xfs_reinit_inode(mp, inode);
> if (error) {
> /*
> * Re-initializing the inode failed, and we are in deep
> --
> 2.5.0
>
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