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Commit 986ab098 authored by Lino Sanfilippo's avatar Lino Sanfilippo Committed by Eric Paris
Browse files

fsnotify: use a mutex instead of a spinlock to protect a groups mark list 



Replaces the groups mark_lock spinlock with a mutex. Using a mutex instead
of a spinlock results in more flexibility (i.e it allows to sleep while the
lock is held).

Signed-off-by: default avatarLino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent 6dfbd149

fs/notify/group.c

+1 −1
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops) 
	init_waitqueue_head(&group->notification_waitq);

	group->max_events = UINT_MAX;



	spin_lock_init(&group->mark_lock);

	mutex_init(&group->mark_mutex);

	INIT_LIST_HEAD(&group->marks_list);



	group->ops = ops;

fs/notify/inode_mark.c

+2 −2
Original line number Diff line number Diff line
@@ -63,8 +63,8 @@ void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) 
{

	struct inode *inode = mark->i.inode;



	BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));

	assert_spin_locked(&mark->lock);

	assert_spin_locked(&mark->group->mark_lock);



	spin_lock(&inode->i_lock);
@@ -191,8 +191,8 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark, 


	mark->flags |= FSNOTIFY_MARK_FLAG_INODE;



	BUG_ON(!mutex_is_locked(&group->mark_mutex));

	assert_spin_locked(&mark->lock);

	assert_spin_locked(&group->mark_lock);



	spin_lock(&inode->i_lock);

fs/notify/mark.c

+9 −9
Original line number Diff line number Diff line
@@ -136,13 +136,13 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark) 
	group = mark->group;

	spin_unlock(&mark->lock);



	spin_lock(&group->mark_lock);

	mutex_lock(&group->mark_mutex);

	spin_lock(&mark->lock);



	/* something else already called this function on this mark */

	if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {

		spin_unlock(&mark->lock);

		spin_unlock(&group->mark_lock);

		mutex_unlock(&group->mark_mutex);

		goto put_group;

	}
@@ -159,7 +159,7 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark) 
	list_del_init(&mark->g_list);



	spin_unlock(&mark->lock);

	spin_unlock(&group->mark_lock);

	mutex_unlock(&group->mark_mutex);



	spin_lock(&destroy_lock);

	list_add(&mark->destroy_list, &destroy_list);
@@ -232,11 +232,11 @@ int fsnotify_add_mark(struct fsnotify_mark *mark, 


	/*

	 * LOCKING ORDER!!!!

	 * group->mark_lock

	 * group->mark_mutex

	 * mark->lock

	 * inode->i_lock

	 */

	spin_lock(&group->mark_lock);

	mutex_lock(&group->mark_mutex);



	spin_lock(&mark->lock);

	mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE;
@@ -263,7 +263,7 @@ int fsnotify_add_mark(struct fsnotify_mark *mark, 
	fsnotify_set_mark_mask_locked(mark, mark->mask);

	spin_unlock(&mark->lock);



	spin_unlock(&group->mark_lock);

	mutex_unlock(&group->mark_mutex);



	if (inode)

		__fsnotify_update_child_dentry_flags(inode);
@@ -277,7 +277,7 @@ int fsnotify_add_mark(struct fsnotify_mark *mark, 
	atomic_dec(&group->num_marks);



	spin_unlock(&mark->lock);

	spin_unlock(&group->mark_lock);

	mutex_unlock(&group->mark_mutex);



	spin_lock(&destroy_lock);

	list_add(&mark->destroy_list, &destroy_list);
@@ -296,7 +296,7 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, 
	struct fsnotify_mark *lmark, *mark;

	LIST_HEAD(free_list);



	spin_lock(&group->mark_lock);

	mutex_lock(&group->mark_mutex);

	list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) {

		if (mark->flags & flags) {

			list_add(&mark->free_g_list, &free_list);
@@ -304,7 +304,7 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, 
			fsnotify_get_mark(mark);

		}

	}

	spin_unlock(&group->mark_lock);

	mutex_unlock(&group->mark_mutex);



	list_for_each_entry_safe(mark, lmark, &free_list, free_g_list) {

		fsnotify_destroy_mark(mark);

fs/notify/vfsmount_mark.c

+2 −2
Original line number Diff line number Diff line
@@ -88,8 +88,8 @@ void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark) 
{

	struct vfsmount *mnt = mark->m.mnt;



	BUG_ON(!mutex_is_locked(&mark->group->mark_mutex));

	assert_spin_locked(&mark->lock);

	assert_spin_locked(&mark->group->mark_lock);



	spin_lock(&mnt->mnt_root->d_lock);
@@ -151,8 +151,8 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, 


	mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT;



	BUG_ON(!mutex_is_locked(&group->mark_mutex));

	assert_spin_locked(&mark->lock);

	assert_spin_locked(&group->mark_lock);



	spin_lock(&mnt->mnt_root->d_lock);

include/linux/fsnotify_backend.h

+1 −1
Original line number Diff line number Diff line
@@ -141,7 +141,7 @@ struct fsnotify_group { 
	unsigned int priority;



	/* stores all fastpath marks assoc with this group so they can be cleaned on unregister */

	spinlock_t mark_lock;		/* protect marks_list */

	struct mutex mark_mutex;	/* protect marks_list */

	atomic_t num_marks;		/* 1 for each mark and 1 for not being

					 * past the point of no return when freeing

					 * a group */