On Mon, Apr 26, 2021 at 9:42 PM 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 creating a mark.
Ok for the split, but...
>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
> ---
> fs/notify/fanotify/fanotify_user.c | 35 +++++++++++++++++++-----------
> 1 file changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 0332c4afeec3..e0d113e3b65c 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -1055,7 +1055,23 @@ 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 path *path)
This helper can take a 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 (!path->dentry->d_sb->s_export_op ||
> + !path->dentry->d_sb->s_export_op->fh_to_dentry)
> + return -EOPNOTSUPP;
> +
> + return 0;
> +}
> +
> +static int fanotify_check_path_fsid(struct path *path, __kernel_fsid_t *fsid)
And so does this helper.
I certainly don't see the need for the _path_ in the helper name.
> {
> __kernel_fsid_t root_fsid;
> int err;
> @@ -1082,17 +1098,6 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
> root_fsid.val[1] != fsid->val[1])
> return -EXDEV;
>
> - /*
> - * 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 (!path->dentry->d_sb->s_export_op ||
> - !path->dentry->d_sb->s_export_op->fh_to_dentry)
> - return -EOPNOTSUPP;
> -
> return 0;
> }
>
> @@ -1230,7 +1235,11 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
> }
>
> if (fid_mode) {
> - ret = fanotify_test_fid(&path, &__fsid);
> + ret = fanotify_check_path_fsid(&path, &__fsid);
> + if (ret)
> + goto path_put_and_out;
> +
> + ret = fanotify_test_fid(&path);
Whether _test_ or _check_ please stick to one.
Thanks,
Amir.
