fsnotify: include vfsmount in should_send_event when appropriate

To ensure that a group will not duplicate events when it receives it based
on the vfsmount and the inode should_send_event test we should distinguish
those two cases.  We pass a vfsmount to this function so groups can make
their own determinations.

Signed-off-by: Eric Paris <eparis@redhat.com>

6 files changed, 29 insertions, 26 deletions

diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
index e0a847bd53be..9eddafa4c7ba 100644
--- a/fs/notify/dnotify/dnotify.c
+++ b/fs/notify/dnotify/dnotify.c
@@ -133,8 +133,8 @@ static int dnotify_handle_event(struct fsnotify_group *group,
  * userspace notification for that pair.
  */
 static bool dnotify_should_send_event(struct fsnotify_group *group,
-                                      struct inode *inode, __u32 mask,
-                                      void *data, int data_type)
+                                      struct inode *inode, struct vfsmount *mnt,
+                                      __u32 mask, void *data, int data_type)
 {
         struct fsnotify_mark_entry *entry;
         bool send;
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index a61aaa710825..78c440c343a8 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -135,13 +135,12 @@ void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
 }
 EXPORT_SYMBOL_GPL(__fsnotify_parent);
 
-static void send_to_group(__u32 mask,
-                          struct fsnotify_group *group,
-                          void *data, int data_is, const char *file_name,
-                          u32 cookie, struct fsnotify_event **event,
-                          struct inode *to_tell)
+static void send_to_group(struct fsnotify_group *group, struct inode *to_tell,
+                          struct vfsmount *mnt, __u32 mask, void *data,
+                          int data_is, u32 cookie, const char *file_name,
+                          struct fsnotify_event **event)
 {
-        if (!group->ops->should_send_event(group, to_tell, mask,
+        if (!group->ops->should_send_event(group, to_tell, mnt, mask,
                                            data, data_is))
                 return;
         if (!*event) {
@@ -159,15 +158,9 @@ static void send_to_group(__u32 mask,
         group->ops->handle_event(group, *event);
 }
 
-static bool needed_by_vfsmount(__u32 test_mask, void *data, int data_is)
+static bool needed_by_vfsmount(__u32 test_mask, struct vfsmount *mnt)
 {
-        struct path *path;
-
-        if (data_is == FSNOTIFY_EVENT_PATH)
-                path = (struct path *)data;
-        else if (data_is == FSNOTIFY_EVENT_FILE)
-                path = &((struct file *)data)->f_path;
-        else
+        if (!mnt)
                 return false;
 
         /* hook in this when mnt->mnt_fsnotify_mask is defined */
@@ -184,6 +177,7 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const
 {
         struct fsnotify_group *group;
         struct fsnotify_event *event = NULL;
+        struct vfsmount *mnt = NULL;
         int idx;
         /* global tests shouldn't care about events on child only the specific event */
         __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
@@ -198,10 +192,15 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const
             !(test_mask & fsnotify_vfsmount_mask))
                 return;
  
+        if (data_is == FSNOTIFY_EVENT_PATH)
+                mnt = ((struct path *)data)->mnt;
+        else if (data_is == FSNOTIFY_EVENT_FILE)
+                mnt = ((struct file *)data)->f_path.mnt;
+
         /* if this inode's directed listeners don't care and nothing on the vfsmount
          * listeners list cares, nothing to do */
         if (!(test_mask & to_tell->i_fsnotify_mask) &&
-            !needed_by_vfsmount(test_mask, data, data_is))
+            !needed_by_vfsmount(test_mask, mnt))
                 return;
 
         /*
@@ -214,16 +213,16 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const
         if (test_mask & to_tell->i_fsnotify_mask) {
                 list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list) {
                         if (test_mask & group->mask) {
-                                send_to_group(mask, group, data, data_is,
-                                              file_name, cookie, &event, to_tell);
+                                send_to_group(group, to_tell, NULL, mask, data, data_is,
+                                              cookie, file_name, &event);
                         }
                 }
         }
-        if (needed_by_vfsmount(test_mask, data, data_is)) {
+        if (needed_by_vfsmount(test_mask, mnt)) {
                 list_for_each_entry_rcu(group, &fsnotify_vfsmount_groups, vfsmount_group_list) {
                         if (test_mask & group->mask) {
-                                send_to_group(mask, group, data, data_is,
-                                              file_name, cookie, &event, to_tell);
+                                send_to_group(group, to_tell, mnt, mask, data, data_is,
+                                              cookie, file_name, &event);
                         }
                 }
         }
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 0a0f5d0f0d0a..8075ae708ed4 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -141,7 +141,8 @@ static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnot
 }
 
 static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode,
-                                      __u32 mask, void *data, int data_type)
+                                      struct vfsmount *mnt, __u32 mask, void *data,
+                                      int data_type)
 {
         struct fsnotify_mark_entry *entry;
         bool send;
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index dea48bee057d..c2a04b7e4fca 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -79,7 +79,8 @@ struct fsnotify_event_private_data;
  */
 struct fsnotify_ops {
         bool (*should_send_event)(struct fsnotify_group *group, struct inode *inode,
-                                  __u32 mask, void *data, int data_type);
+                                  struct vfsmount *mnt, __u32 mask, void *data,
+                                  int data_type);
         int (*handle_event)(struct fsnotify_group *group, struct fsnotify_event *event);
         void (*free_group_priv)(struct fsnotify_group *group);
         void (*freeing_mark)(struct fsnotify_mark_entry *entry, struct fsnotify_group *group);
diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index 04f16887406b..ecf0bf260d09 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -920,7 +920,8 @@ static void audit_tree_freeing_mark(struct fsnotify_mark_entry *entry, struct fs
 }
 
 static bool audit_tree_send_event(struct fsnotify_group *group, struct inode *inode,
-                                  __u32 mask, void *data, int data_type)
+                                  struct vfsmount *mnt, __u32 mask, void *data,
+                                  int data_type)
 {
         return 0;
 }
diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index 83d5f9674cec..6304ee5d7642 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -514,7 +514,8 @@ void audit_remove_watch_rule(struct audit_krule *krule)
 }
 
 static bool audit_watch_should_send_event(struct fsnotify_group *group, struct inode *inode,
-                                          __u32 mask, void *data, int data_type)
+                                          struct vfsmount *mnt, __u32 mask, void *data,
+                                          int data_type)
 {
         struct fsnotify_mark_entry *entry;
         bool send;