#include <asm/atomic.h>
-/* protects writes to fsnotify_groups and fsnotify_mask */
-static DEFINE_MUTEX(fsnotify_grp_mutex);
-/* protects reads while running the fsnotify_groups list */
-struct srcu_struct fsnotify_grp_srcu;
-/* all groups registered to receive inode filesystem notifications */
-LIST_HEAD(fsnotify_inode_groups);
-/* all groups registered to receive mount point filesystem notifications */
-LIST_HEAD(fsnotify_vfsmount_groups);
-/* bitwise OR of all events (FS_*) interesting to some group on this system */
-__u32 fsnotify_inode_mask;
-/* bitwise OR of all events (FS_*) interesting to some group on this system */
-__u32 fsnotify_vfsmount_mask;
-
-/*
- * When a new group registers or changes it's set of interesting events
- * this function updates the fsnotify_mask to contain all interesting events
- */
-void fsnotify_recalc_global_mask(void)
-{
- struct fsnotify_group *group;
- __u32 inode_mask = 0;
- __u32 vfsmount_mask = 0;
- int idx;
-
- idx = srcu_read_lock(&fsnotify_grp_srcu);
- list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list)
- inode_mask |= group->mask;
- list_for_each_entry_rcu(group, &fsnotify_vfsmount_groups, vfsmount_group_list)
- vfsmount_mask |= group->mask;
-
- srcu_read_unlock(&fsnotify_grp_srcu, idx);
-
- fsnotify_inode_mask = inode_mask;
- fsnotify_vfsmount_mask = vfsmount_mask;
-}
-
-/*
- * Update the group->mask by running all of the marks associated with this
- * group and finding the bitwise | of all of the mark->mask. If we change
- * the group->mask we need to update the global mask of events interesting
- * to the system.
- */
-void fsnotify_recalc_group_mask(struct fsnotify_group *group)
-{
- __u32 mask = 0;
- __u32 old_mask = group->mask;
- struct fsnotify_mark *mark;
-
- spin_lock(&group->mark_lock);
- list_for_each_entry(mark, &group->marks_list, g_list)
- mask |= mark->mask;
- spin_unlock(&group->mark_lock);
-
- group->mask = mask;
-
- if (old_mask != mask)
- fsnotify_recalc_global_mask();
-}
-
-void fsnotify_add_vfsmount_group(struct fsnotify_group *group)
-{
- mutex_lock(&fsnotify_grp_mutex);
-
- if (!group->on_vfsmount_group_list)
- list_add_tail_rcu(&group->vfsmount_group_list, &fsnotify_vfsmount_groups);
- group->on_vfsmount_group_list = 1;
-
- mutex_unlock(&fsnotify_grp_mutex);
-}
-
-void fsnotify_add_inode_group(struct fsnotify_group *group)
-{
- mutex_lock(&fsnotify_grp_mutex);
-
- if (!group->on_inode_group_list)
- list_add_tail_rcu(&group->inode_group_list, &fsnotify_inode_groups);
- group->on_inode_group_list = 1;
-
- mutex_unlock(&fsnotify_grp_mutex);
-}
-
/*
* Final freeing of a group
*/
/* clear all inode marks for this group */
fsnotify_clear_marks_by_group(group);
+ synchronize_srcu(&fsnotify_mark_srcu);
+
/* past the point of no return, matches the initial value of 1 */
if (atomic_dec_and_test(&group->num_marks))
fsnotify_final_destroy_group(group);
}
-/*
- * Remove this group from the global list of groups that will get events
- * this can be done even if there are still references and things still using
- * this group. This just stops the group from getting new events.
- */
-static void __fsnotify_evict_group(struct fsnotify_group *group)
-{
- BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
-
- if (group->on_inode_group_list)
- list_del_rcu(&group->inode_group_list);
- group->on_inode_group_list = 0;
- if (group->on_vfsmount_group_list)
- list_del_rcu(&group->vfsmount_group_list);
- group->on_vfsmount_group_list = 0;
-}
-
-/*
- * Called when a group is no longer interested in getting events. This can be
- * used if a group is misbehaving or if for some reason a group should no longer
- * get any filesystem events.
- */
-void fsnotify_evict_group(struct fsnotify_group *group)
-{
- mutex_lock(&fsnotify_grp_mutex);
- __fsnotify_evict_group(group);
- mutex_unlock(&fsnotify_grp_mutex);
-}
-
/*
* Drop a reference to a group. Free it if it's through.
*/
void fsnotify_put_group(struct fsnotify_group *group)
{
- if (!atomic_dec_and_mutex_lock(&group->refcnt, &fsnotify_grp_mutex))
- return;
-
- /*
- * OK, now we know that there's no other users *and* we hold mutex,
- * so no new references will appear
- */
- __fsnotify_evict_group(group);
-
- /*
- * now it's off the list, so the only thing we might care about is
- * srcu access....
- */
- mutex_unlock(&fsnotify_grp_mutex);
- synchronize_srcu(&fsnotify_grp_srcu);
-
- /* and now it is really dead. _Nothing_ could be seeing it */
- fsnotify_recalc_global_mask();
- fsnotify_destroy_group(group);
+ if (atomic_dec_and_test(&group->refcnt))
+ fsnotify_destroy_group(group);
}
/*
init_waitqueue_head(&group->notification_waitq);
group->max_events = UINT_MAX;
- INIT_LIST_HEAD(&group->inode_group_list);
- INIT_LIST_HEAD(&group->vfsmount_group_list);
-
spin_lock_init(&group->mark_lock);
INIT_LIST_HEAD(&group->marks_list);
projects / mv-sheeva.git / blobdiff