fsnotify: Lock object list with connector lock
So far list of marks attached to an object (inode / vfsmount) was
protected by i_lock or mnt_root->d_lock. This dictates that the list
must be empty before the object can be destroyed although the list is
now anchored in the fsnotify_mark_connector structure. Protect the list
by a spinlock in the fsnotify_mark_connector structure to decouple
lifetime of a list of marks from a lifetime of the object. This also
simplifies the code quite a bit since we don't have to differentiate
between inode and vfsmount lists in quite a few places anymore.
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index b954f1b..02c6fac 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -201,6 +201,7 @@ struct fsnotify_group {
* inode / vfsmount gets freed.
*/
struct fsnotify_mark_connector {
+ spinlock_t lock;
#define FSNOTIFY_OBJ_TYPE_INODE 0x01
#define FSNOTIFY_OBJ_TYPE_VFSMOUNT 0x02
unsigned int flags; /* Type of object [lock] */
@@ -240,7 +241,7 @@ struct fsnotify_mark {
struct list_head g_list;
/* Protects inode / mnt pointers, flags, masks */
spinlock_t lock;
- /* List of marks for inode / vfsmount [obj_lock] */
+ /* List of marks for inode / vfsmount [connector->lock] */
struct hlist_node obj_list;
/* Head of list of marks for an object [mark->lock, group->mark_mutex] */
struct fsnotify_mark_connector *connector;