fsnotify: Avoid double locking in fsnotify_detach_from_object()

We lock object list lock in fsnotify_detach_from_object() twice - once
to detach mark and second time to recalculate mask. That is unnecessary
and later it will become problematic as we will free the connector as
soon as there is no mark in it. So move recalculation of fsnotify mask
into the same critical section that is detaching mark.

This also removes recalculation of child dentry flags from
fsnotify_detach_from_object(). That is however fine. Those marks will
get recalculated once some event happens on a child.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 08ab7b252322da210e2953478af3b712c6937e24..416ba91750a9f68707d720a649b147ccbd7244cd 100644 (file)
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -158,9 +158,9 @@ static struct inode *fsnotify_detach_from_object(struct fsnotify_mark *mark)
                if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
                        inode = conn->inode;
        }
+       __fsnotify_recalc_mask(conn);
        mark->connector = NULL;
        spin_unlock(lock);
-       fsnotify_recalc_mask(conn);
 
        return inode;
 }