On Fri, May 21, 2021 at 5:42 AM Gabriel Krisman Bertazi
<krisman@xxxxxxxxxxxxx> wrote:
>
> FAN_ERROR will require fsid, but not necessarily require the filesystem
> to expose a file handle. Split those checks into different functions, so
> they can be used separately when setting up an event.
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
>
> Changes since v1:
> (Amir)
> - Rename fanotify_check_path_fsid -> fanotify_test_fsid
> - Use dentry directly instead of path
> ---
> fs/notify/fanotify/fanotify_user.c | 43 ++++++++++++++++++------------
> 1 file changed, 26 insertions(+), 17 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 3ccdee3c9f1e..9cc6c8808ed5 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -1178,15 +1178,31 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
> }
>
> /* Check if filesystem can encode a unique fid */
> -static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
> +static int fanotify_test_fid(struct dentry *dentry)
> +{
> + /*
> + * We need to make sure that the file system supports at least
> + * encoding a file handle so user can use name_to_handle_at() to
> + * compare fid returned with event to the file handle of watched
> + * objects. However, name_to_handle_at() requires that the
> + * filesystem also supports decoding file handles.
> + */
> + if (!dentry->d_sb->s_export_op ||
> + !dentry->d_sb->s_export_op->fh_to_dentry)
> + return -EOPNOTSUPP;
> +
> + return 0;
> +}
> +
Nit: move this helper below test_fsid.
The patch will be smaller and easier to review and more
important, less churn that hides the true git blame on the code above.
Thanks,
Amir.
