--
Changes since v6:
  - Always use data field for superblock retrieval
Changes since v5:
  - add fsnotify_data_sb handle to retrieve sb from the data field. (jan)
---
 fs/notify/fsnotify.c             |  7 +++----
 include/linux/fsnotify_backend.h | 15 +++++++++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 963e6ce75b96..fde3a1115a17 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c

@@ -455,16 +455,16 @@ static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info)
  *             @file_name is relative to
  * @file_name: optional file name associated with event
  * @inode:     optional inode associated with event -
- *             either @dir or @inode must be non-NULL.
- *             if both are non-NULL event may be reported to both.
+ *             If @dir and @inode are both non-NULL, event may be
+ *             reported to both.
  * @cookie:    inotify rename cookie
  */
 int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
             const struct qstr *file_name, struct inode *inode, u32 cookie)
 {
        const struct path *path = fsnotify_data_path(data, data_type);
+       struct super_block *sb = fsnotify_data_sb(data, data_type);
        struct fsnotify_iter_info iter_info = {};
-       struct super_block *sb;
        struct mount *mnt = NULL;
        struct inode *parent = NULL;
        int ret = 0;

@@ -483,7 +483,6 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
                 */
                parent = dir;
        }
-       sb = inode->i_sb;

        /*
         * Optimization: srcu_read_lock() has a memory barrier which can

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index b323d0c4b967..035438fe4a43 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h

@@ -289,6 +289,21 @@ static inline const struct path *fsnotify_data_path(const void *data,
        }
 }

+static inline struct super_block *fsnotify_data_sb(const void *data,
+                                                  int data_type)
+{
+       switch (data_type) {
+       case FSNOTIFY_EVENT_INODE:
+               return ((struct inode *)data)->i_sb;
+       case FSNOTIFY_EVENT_DENTRY:
+               return ((struct dentry *)data)->d_sb;
+       case FSNOTIFY_EVENT_PATH:
+               return ((const struct path *)data)->dentry->d_sb;
+       default:
+               return NULL;
+       }
+}
+
 enum fsnotify_obj_type {
        FSNOTIFY_OBJ_TYPE_INODE,
        FSNOTIFY_OBJ_TYPE_PARENT,
--

2.33.0