diff mbox series

[02/11] fanotify: Split fsid check from other fid mode checks

Message ID 20210521024134.1032503-3-krisman@collabora.com (mailing list archive)
State New, archived
Headers show
Series File system wide monitoring | expand

Commit Message

Gabriel Krisman Bertazi May 21, 2021, 2:41 a.m. UTC 
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@collabora.com>

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(-)

Comments

Amir Goldstein May 21, 2021, 8:33 a.m. UTC | #1 
On Fri, May 21, 2021 at 5:42 AM Gabriel Krisman Bertazi
<krisman@collabora.com> 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@collabora.com>
>
> 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.
diff mbox series

Patch

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;
+}
+
+static int fanotify_test_fsid(struct dentry *dentry, __kernel_fsid_t *fsid)
 {
 	__kernel_fsid_t root_fsid;
 	int err;
 
 	/*
-	 * Make sure path is not in filesystem with zero fsid (e.g. tmpfs).
+	 * Make sure dentry is not of a filesystem with zero fsid (e.g. tmpfs).
 	 */
-	err = vfs_get_fsid(path->dentry, fsid);
+	err = vfs_get_fsid(dentry, fsid);
 	if (err)
 		return err;
 
@@ -1194,10 +1210,10 @@  static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
 		return -ENODEV;
 
 	/*
-	 * Make sure path is not inside a filesystem subvolume (e.g. btrfs)
+	 * Make sure dentry is not of a filesystem subvolume (e.g. btrfs)
 	 * which uses a different fsid than sb root.
 	 */
-	err = vfs_get_fsid(path->dentry->d_sb->s_root, &root_fsid);
+	err = vfs_get_fsid(dentry->d_sb->s_root, &root_fsid);
 	if (err)
 		return err;
 
@@ -1205,17 +1221,6 @@  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;
 }
 
@@ -1362,7 +1367,11 @@  static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	}
 
 	if (fid_mode) {
-		ret = fanotify_test_fid(&path, &__fsid);
+		ret = fanotify_test_fsid(path.dentry, &__fsid);
+		if (ret)
+			goto path_put_and_out;
+
+		ret = fanotify_test_fid(path.dentry);
 		if (ret)
 			goto path_put_and_out;