nfs4: treat lock owners as opaque values

Do the following set of ops with a file on a NFSv4 mount:

    exec 3>>/file/on/nfsv4
    flock -x 3
    exec 3>&-

You'll see the LOCK request go across the wire, but no LOCKU when the
file is closed.

What happens is that the fd is passed across a fork, and the final close
is done in a different process than the opener. That makes
__nfs4_find_lock_state miss finding the correct lock state because it
uses the fl_pid as a search key. A new one is created, and the locking
code treats it as a delegation stateid (because NFS_LOCK_INITIALIZED
isn't set).

The root cause of this breakage seems to be commit 77041ed9b49a9e
(NFSv4: Ensure the lockowners are labelled using the fl_owner and/or
fl_pid).

That changed it so that flock lockowners are allocated based on the
fl_pid. I think this is incorrect. flock locks should be "owned" by the
struct file, and that is already accounted for in the fl_owner field of
the lock request when it comes through nfs_flock.

This patch basically reverts the above commit and with it, a LOCKU is
sent in the above reproducer.

Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 1 insertions, 12 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index b8ea4a26998c..19f567c39670 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -129,17 +129,6 @@ enum {
  * LOCK: one nfs4_state (LOCK) to hold the lock stateid nfs4_state(OPEN)
  */
 
-struct nfs4_lock_owner {
-	unsigned int lo_type;
-#define NFS4_ANY_LOCK_TYPE	(0U)
-#define NFS4_FLOCK_LOCK_TYPE	(1U << 0)
-#define NFS4_POSIX_LOCK_TYPE	(1U << 1)
-	union {
-		fl_owner_t posix_owner;
-		pid_t flock_owner;
-	} lo_u;
-};
-
 struct nfs4_lock_state {
 	struct list_head	ls_locks;	/* Other lock stateids */
 	struct nfs4_state *	ls_state;	/* Pointer to open state */
@@ -149,7 +138,7 @@ struct nfs4_lock_state {
 	struct nfs_seqid_counter	ls_seqid;
 	nfs4_stateid		ls_stateid;
 	atomic_t		ls_count;
-	struct nfs4_lock_owner	ls_owner;
+	fl_owner_t		ls_owner;
 };
 
 /* bits for nfs4_state->flags */