Re: [PATCH 2/2] shmem: allow reporting fanotify events with file handles on tmpfs

[Jan Kara <jack@suse.cz>]

On Mon 22-03-21 19:39:44, Amir Goldstein wrote:
> Since kernel v5.1, fanotify_init(2) supports the flag FAN_REPORT_FID
> for identifying objects using file handle and fsid in events.
> 
> fanotify_mark(2) fails with -ENODEV when trying to set a mark on
> filesystems that report null f_fsid in stasfs(2).
> 
> Use the digest of uuid as f_fsid for tmpfs to uniquely identify tmpfs
> objects as best as possible and allow setting an fanotify mark that
> reports events with file handles on tmpfs.
> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>

Hugh, any opinion on this patch?

								Honza

> ---
>  mm/shmem.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/shmem.c b/mm/shmem.c
> index b2db4ed0fbc7..162d8f8993bb 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2846,6 +2846,9 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
>  		buf->f_ffree = sbinfo->free_inodes;
>  	}
>  	/* else leave those fields 0 like simple_statfs */
> +
> +	buf->f_fsid = uuid_to_fsid(dentry->d_sb->s_uuid.b);
> +
>  	return 0;
>  }
>  
> -- 
> 2.25.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR