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/nommu.c b/mm/nommu.c
index 8740213..a554e5a 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -995,7 +995,7 @@
(file->f_mode & FMODE_WRITE))
return -EACCES;
- if (locks_verify_locked(file_inode(file)))
+ if (locks_verify_locked(file))
return -EAGAIN;
if (!(capabilities & BDI_CAP_MAP_DIRECT))