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Commit d8153d4d authored by Lino Sanfilippo's avatar Lino Sanfilippo Committed by Eric Paris
Browse files

inotify, fanotify: replace fsnotify_put_group() with fsnotify_destroy_group() 



Currently in fsnotify_put_group() the ref count of a group is decremented and if
it becomes 0 fsnotify_destroy_group() is called. Since a groups ref count is only
at group creation set to 1 and never increased after that a call to fsnotify_put_group()
always results in a call to fsnotify_destroy_group().
With this patch fsnotify_destroy_group() is called directly.

Signed-off-by: default avatarLino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent a0d271cb

fs/notify/fanotify/fanotify_user.c

+7 −7
Original line number Diff line number Diff line
@@ -415,7 +415,7 @@ static int fanotify_release(struct inode *ignored, struct file *file) 
	wake_up(&group->fanotify_data.access_waitq);

#endif

	/* matches the fanotify_init->fsnotify_alloc_group */

	fsnotify_put_group(group);

	fsnotify_destroy_group(group);



	return 0;

}
@@ -728,13 +728,13 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) 
		break;

	default:

		fd = -EINVAL;

		goto out_put_group;

		goto out_destroy_group;

	}



	if (flags & FAN_UNLIMITED_QUEUE) {

		fd = -EPERM;

		if (!capable(CAP_SYS_ADMIN))

			goto out_put_group;

			goto out_destroy_group;

		group->max_events = UINT_MAX;

	} else {

		group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS;
@@ -743,7 +743,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) 
	if (flags & FAN_UNLIMITED_MARKS) {

		fd = -EPERM;

		if (!capable(CAP_SYS_ADMIN))

			goto out_put_group;

			goto out_destroy_group;

		group->fanotify_data.max_marks = UINT_MAX;

	} else {

		group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS;
@@ -751,12 +751,12 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) 


	fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);

	if (fd < 0)

		goto out_put_group;

		goto out_destroy_group;



	return fd;



out_put_group:

	fsnotify_put_group(group);

out_destroy_group:

	fsnotify_destroy_group(group);

	return fd;

}

fs/notify/group.c

+1 −1
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ void fsnotify_final_destroy_group(struct fsnotify_group *group) 
 * situtation, the fsnotify_final_destroy_group will get called when that final

 * mark is freed.

 */

static void fsnotify_destroy_group(struct fsnotify_group *group)

void fsnotify_destroy_group(struct fsnotify_group *group)

{

	/* clear all inode marks for this group */

	fsnotify_clear_marks_by_group(group);

fs/notify/inotify/inotify_user.c

+3 −5
Original line number Diff line number Diff line
@@ -293,10 +293,8 @@ static int inotify_release(struct inode *ignored, struct file *file) 


	pr_debug("%s: group=%p\n", __func__, group);



	fsnotify_clear_marks_by_group(group);



	/* free this group, matching get was inotify_init->fsnotify_obtain_group */

	fsnotify_put_group(group);

	fsnotify_destroy_group(group);



	return 0;

}
@@ -712,7 +710,7 @@ static struct fsnotify_group *inotify_new_group(unsigned int max_events) 


	if (atomic_inc_return(&group->inotify_data.user->inotify_devs) >

	    inotify_max_user_instances) {

		fsnotify_put_group(group);

		fsnotify_destroy_group(group);

		return ERR_PTR(-EMFILE);

	}
@@ -741,7 +739,7 @@ SYSCALL_DEFINE1(inotify_init1, int, flags) 
	ret = anon_inode_getfd("inotify", &inotify_fops, group,

				  O_RDONLY | flags);

	if (ret < 0)

		fsnotify_put_group(group);

		fsnotify_destroy_group(group);



	return ret;

}

include/linux/fsnotify_backend.h

+2 −1
Original line number Diff line number Diff line
@@ -364,7 +364,8 @@ static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode 
extern struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops);

/* drop reference on a group from fsnotify_alloc_group */

extern void fsnotify_put_group(struct fsnotify_group *group);



/* destroy group */

extern void fsnotify_destroy_group(struct fsnotify_group *group);

/* take a reference to an event */

extern void fsnotify_get_event(struct fsnotify_event *event);

extern void fsnotify_put_event(struct fsnotify_event *event);