fsnotify: use an explicit flag to indicate fsnotify_destroy_mark has been called
Currently fsnotify check is mark->group is NULL to decide if
fsnotify_destroy_mark() has already been called or not. With the upcoming
rcu work it is a heck of a lot easier to use an explicit flag than worry
about group being set to NULL.
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c
index 455cb41..37b460f 100644
--- a/fs/notify/inode_mark.c
+++ b/fs/notify/inode_mark.c
@@ -187,7 +187,7 @@
struct hlist_node *node, *last = NULL;
int ret = 0;
- mark->flags = FSNOTIFY_MARK_FLAG_INODE;
+ mark->flags |= FSNOTIFY_MARK_FLAG_INODE;
assert_spin_locked(&mark->lock);
assert_spin_locked(&group->mark_lock);
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 8f3b0e7..69c5a16 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -121,12 +121,14 @@
group = mark->group;
- /* if !group something else already marked this to die */
- if (!group) {
+ /* something else already called this function on this mark */
+ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
spin_unlock(&mark->lock);
return;
}
+ mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
+
/* 1 from caller and 1 for being on i_list/g_list */
BUG_ON(atomic_read(&mark->refcnt) < 2);
@@ -141,7 +143,6 @@
BUG();
list_del_init(&mark->g_list);
- mark->group = NULL;
fsnotify_put_mark(mark); /* for i_list and g_list */
@@ -229,6 +230,8 @@
spin_lock(&mark->lock);
spin_lock(&group->mark_lock);
+ mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE;
+
mark->group = group;
list_add(&mark->g_list, &group->marks_list);
atomic_inc(&group->num_marks);
@@ -258,7 +261,7 @@
return ret;
err:
- mark->group = NULL;
+ mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
list_del_init(&mark->g_list);
atomic_dec(&group->num_marks);
fsnotify_put_mark(mark);
diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c
index b7ae640..56772b5 100644
--- a/fs/notify/vfsmount_mark.c
+++ b/fs/notify/vfsmount_mark.c
@@ -145,7 +145,7 @@
struct hlist_node *node, *last = NULL;
int ret = 0;
- mark->flags = FSNOTIFY_MARK_FLAG_VFSMOUNT;
+ mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;
assert_spin_locked(&mark->lock);
assert_spin_locked(&group->mark_lock);
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 3410d38..8e24cdf 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -300,6 +300,7 @@
#define FSNOTIFY_MARK_FLAG_VFSMOUNT 0x02
#define FSNOTIFY_MARK_FLAG_OBJECT_PINNED 0x04
#define FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY 0x08
+#define FSNOTIFY_MARK_FLAG_ALIVE 0x10
unsigned int flags; /* vfsmount or inode mark? */
void (*free_mark)(struct fsnotify_mark *mark); /* called on final put+free */
};
