fsnotify: correctly handle return codes from listeners

When fsnotify groups return errors they are ignored.  For permissions
events these should be passed back up the stack, but for most events these
should continue to be ignored.

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

2 files changed, 14 insertions, 8 deletions

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 4498a208df94..57ecadd85abf 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -252,20 +252,23 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
 
                 if (inode_group > vfsmount_group) {
                         /* handle inode */
-                        send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
-                                      data_is, cookie, file_name, &event);
+                        ret = send_to_group(to_tell, NULL, inode_mark, NULL, mask, data,
+                                            data_is, cookie, file_name, &event);
                         /* we didn't use the vfsmount_mark */
                         vfsmount_group = NULL;
                 } else if (vfsmount_group > inode_group) {
-                        send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
-                                      data_is, cookie, file_name, &event);
+                        ret = send_to_group(to_tell, mnt, NULL, vfsmount_mark, mask, data,
+                                            data_is, cookie, file_name, &event);
                         inode_group = NULL;
                 } else {
-                        send_to_group(to_tell, mnt, inode_mark, vfsmount_mark,
-                                      mask, data, data_is, cookie, file_name,
-                                      &event);
+                        ret = send_to_group(to_tell, mnt, inode_mark, vfsmount_mark,
+                                            mask, data, data_is, cookie, file_name,
+                                            &event);
                 }
 
+                if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS))
+                        goto out;
+
                 if (inode_group)
                         inode_node = srcu_dereference(inode_node->next,
                                                       &fsnotify_mark_srcu);
@@ -273,7 +276,8 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
                         vfsmount_node = srcu_dereference(vfsmount_node->next,
                                                          &fsnotify_mark_srcu);
         }
-
+        ret = 0;
+out:
         srcu_read_unlock(&fsnotify_mark_srcu, idx);
         /*
          * fsnotify_create_event() took a reference so the event can't be cleaned
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 825329534162..026892187c83 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -64,6 +64,8 @@
 
 #define FS_MOVE                 (FS_MOVED_FROM | FS_MOVED_TO)
 
+#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
+
 #define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
                              FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN | \
                              FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \