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: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Eric Paris <eparis@redhat.com>

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 3568c8a8b1387aea2845d6998b2b7e6d1dc6dcb2..8de50b8660c70d54ba5055cea0f3464e3cffa9b9 100644 (file)
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -419,7 +419,7 @@ 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;
 }
@@ -732,13 +732,13 @@ 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;
@@ -747,7 +747,7 @@ 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;
@@ -755,12 +755,12 @@ 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;
 }
 

diff --git a/fs/notify/group.c b/fs/notify/group.c
index 63fc294a469268d06d9ae1cc9f3d19f3ba95f695..cfda328c3d11035011a639b5a613791bd2df40a2 100644 (file)
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -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);

diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index 8445fbc8985cae9c7357f59f97fface6e482815b..dbafbfc8ceca86040ba30b6d3d18cef81688f828 100644 (file)
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -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;
 }

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 91d0e0a34ef3185a6051d8394cab63dfb76a04cb..afac095210067b9f15b36af3712e02abc5c48a94 100644 (file)
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -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);