locks: fix locks_mandatory_locked to respect file-private locks
As Trond pointed out, you can currently deadlock yourself by setting a
file-private lock on a file that requires mandatory locking and then
trying to do I/O on it.
Avoid this problem by plumbing some knowledge of file-private locks into
the mandatory locking code. In order to do this, we must pass down
information about the struct file that's being used to
locks_verify_locked.
Reported-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/mm/mmap.c b/mm/mmap.c
index 20ff0c3..5932ce9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1299,7 +1299,7 @@
/*
* Make sure there are no mandatory locks on the file.
*/
- if (locks_verify_locked(inode))
+ if (locks_verify_locked(file))
return -EAGAIN;
vm_flags |= VM_SHARED | VM_MAYSHARE;