Re: [PATCH 3/4] fuse: don't unhash root

[Bernd Schubert <bernd.schubert@fastmail.fm>]

On 2/28/24 17:02, Miklos Szeredi wrote:
> The root inode is assumed to be always hashed.  Do not unhash the root
> inode even if it is marked BAD.
> 
> Fixes: 5d069dbe8aaf ("fuse: fix bad inode")
> Cc: <stable@vger.kernel.org> # v5.11
> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
> ---
>  fs/fuse/fuse_i.h | 1 -
>  fs/fuse/inode.c  | 7 +++++--
>  2 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
> index 7bd3552b1e80..4ef6087f0e5c 100644
> --- a/fs/fuse/fuse_i.h
> +++ b/fs/fuse/fuse_i.h
> @@ -994,7 +994,6 @@ static inline bool fuse_stale_inode(const struct inode *inode, int generation,
>  
>  static inline void fuse_make_bad(struct inode *inode)
>  {
> -	remove_inode_hash(inode);
>  	set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
>  }

Hmm, what about callers like fuse_direntplus_link? It now never removes
the inode hash for these? Depend on lookup/revalidate?


Thanks,
Bernd

>  
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index c26a84439934..aa0614e8791c 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -475,8 +475,11 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
>  	} else if (fuse_stale_inode(inode, generation, attr)) {
>  		/* nodeid was reused, any I/O on the old inode should fail */
>  		fuse_make_bad(inode);
> -		iput(inode);
> -		goto retry;
> +		if (inode != d_inode(sb->s_root)) {
> +			remove_inode_hash(inode);
> +			iput(inode);
> +			goto retry;
> +		}
>  	}
>  	fi = get_fuse_inode(inode);
>  	spin_lock(&fi->lock);