[PATCH] smb3: log warning if CSC policy conflicts with linux kernel client cache mount option

[ronnie sahlberg]

Reviewed-by: Ronnie Sahlberg <lsahlber at redhat.com>


On Wed, Sep 4, 2019 at 8:54 AM Steve French <smfrench at gmail.com> wrote:
>
> If the server config (e.g. Samba smb.conf "csc policy = disable)
> for the share indicates that the share should not be cached, log
> a warning message in the Linux kernel client if forced client side
> caching ("cache=ro" or "cache=singleclient") was requested on mount.
>
> Signed-off-by: Steve French <stfrench at microsoft.com>
> ---
>  fs/cifs/connect.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index d9a995588c74..85f8d943a05a 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -3478,6 +3478,14 @@ cifs_get_tcon(struct cifs_ses *ses, struct
> smb_vol *volume_info)
>          tcon->use_resilient = true;
>      }
>
> +    /* If the user really knows what they are doing they can override */
> +    if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
> +        if (volume_info->cache_ro)
> +            cifs_dbg(VFS, "cache=ro requested on mount but NO_CACHING
> flag set on share\n");
> +        else if (volume_info->cache_rw)
> +            cifs_dbg(VFS, "cache=singleclient requested on mount but
> NO_CACHING flag set on share\n");
> +    }
> +
>      /*
>       * We can have only one retry value for a connection to a share so for
>       * resources mounted more than once to the same server share the last
>
> --
> Thanks,
>
> Steve