fanotify: Dont try to open a file descriptor for the overflow event

We should not try to open a file descriptor for the overflow event since this
will always fail.

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 ca54957b1f61e986ac2b4793e6be2146607e92eb..dccd7985e65a843a7b917437a3c1f28786a6e16a 100644 (file)
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -110,6 +110,8 @@ static int fill_event_metadata(struct fsnotify_group *group,
                                   struct fanotify_event_metadata *metadata,
                                   struct fsnotify_event *event)
 {
+       int ret = 0;
+
        pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
                 group, metadata, event);
 
@@ -117,9 +119,15 @@ static int fill_event_metadata(struct fsnotify_group *group,
        metadata->vers = FANOTIFY_METADATA_VERSION;
        metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
        metadata->pid = pid_vnr(event->tgid);
-       metadata->fd = create_fd(group, event);
+       if (unlikely(event->mask & FAN_Q_OVERFLOW))
+               metadata->fd = FAN_NOFD;
+       else {
+               metadata->fd = create_fd(group, event);
+               if (metadata->fd < 0)
+                       ret = metadata->fd;
+       }
 
-       return metadata->fd;
+       return ret;
 }
 
 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
@@ -261,7 +269,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
        if (ret < 0)
                goto out;
 
-       fd = ret;
+       fd = fanotify_event_metadata.fd;
        ret = prepare_for_access_response(group, event, fd);
        if (ret)
                goto out_close_fd;
@@ -275,7 +283,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 out_kill_access_response:
        remove_access_response(group, event, fd);
 out_close_fd:
-       sys_close(fd);
+       if (fd != FAN_NOFD)
+               sys_close(fd);
 out:
 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
        if (event->mask & FAN_ALL_PERM_EVENTS) {