From 2cf1345968df31bc605e867cd87a649452881c65 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Sat, 24 Jan 2015 16:03:52 -0500
Subject: [PATCH] NFSv4: Update of VFS byte range lock must be atomic with the
 stateid update

Ensure that we test the lock stateid remained unchanged while we were
updating the VFS tracking of the byte range lock. Have the process
replay the lock to the server if we detect that was not the case.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/nfs4proc.c       | 37 +++++++++++++++----------------------
 include/linux/nfs_xdr.h |  1 +
 2 files changed, 16 insertions(+), 22 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 41e7c2fc046e6..9f6baf98942c2 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5420,9 +5420,10 @@ static void nfs4_locku_done(struct rpc_task *task, void *data)
 	switch (task->tk_status) {
 		case 0:
 			renew_lease(calldata->server, calldata->timestamp);
-			nfs4_update_lock_stateid(calldata->lsp,
-					&calldata->res.stateid);
-			break;
+			do_vfs_lock(calldata->fl.fl_file, &calldata->fl);
+			if (nfs4_update_lock_stateid(calldata->lsp,
+					&calldata->res.stateid))
+				break;
 		case -NFS4ERR_BAD_STATEID:
 		case -NFS4ERR_OLD_STATEID:
 		case -NFS4ERR_STALE_STATEID:
@@ -5661,6 +5662,13 @@ static void nfs4_lock_done(struct rpc_task *task, void *calldata)
 	case 0:
 		renew_lease(NFS_SERVER(data->ctx->dentry->d_inode),
 				data->timestamp);
+		if (data->arg.new_lock) {
+			data->fl.fl_flags &= ~(FL_SLEEP | FL_ACCESS);
+			if (do_vfs_lock(data->fl.fl_file, &data->fl) < 0) {
+				rpc_restart_call_prepare(task);
+				break;
+			}
+		}
 		if (data->arg.new_lock_owner != 0) {
 			nfs_confirm_seqid(&lsp->ls_seqid, 0);
 			nfs4_stateid_copy(&lsp->ls_stateid, &data->res.stateid);
@@ -5760,7 +5768,8 @@ static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *f
 		if (recovery_type == NFS_LOCK_RECLAIM)
 			data->arg.reclaim = NFS_LOCK_RECLAIM;
 		nfs4_set_sequence_privileged(&data->arg.seq_args);
-	}
+	} else
+		data->arg.new_lock = 1;
 	task = rpc_run_task(&task_setup_data);
 	if (IS_ERR(task))
 		return PTR_ERR(task);
@@ -5884,10 +5893,8 @@ static int nfs41_lock_expired(struct nfs4_state *state, struct file_lock *reques
 
 static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
 {
-	struct nfs4_state_owner *sp = state->owner;
 	struct nfs_inode *nfsi = NFS_I(state->inode);
 	unsigned char fl_flags = request->fl_flags;
-	unsigned int seq;
 	int status = -ENOLCK;
 
 	if ((fl_flags & FL_POSIX) &&
@@ -5907,25 +5914,11 @@ static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock
 		/* ...but avoid races with delegation recall... */
 		request->fl_flags = fl_flags & ~FL_SLEEP;
 		status = do_vfs_lock(request->fl_file, request);
-		goto out_unlock;
-	}
-	seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
-	up_read(&nfsi->rwsem);
-	status = _nfs4_do_setlk(state, cmd, request, NFS_LOCK_NEW);
-	if (status != 0)
+		up_read(&nfsi->rwsem);
 		goto out;
-	down_read(&nfsi->rwsem);
-	if (read_seqcount_retry(&sp->so_reclaim_seqcount, seq)) {
-		status = -NFS4ERR_DELAY;
-		goto out_unlock;
 	}
-	/* Note: we always want to sleep here! */
-	request->fl_flags = fl_flags | FL_SLEEP;
-	if (do_vfs_lock(request->fl_file, request) < 0)
-		printk(KERN_WARNING "NFS: %s: VFS is out of sync with lock "
-			"manager!\n", __func__);
-out_unlock:
 	up_read(&nfsi->rwsem);
+	status = _nfs4_do_setlk(state, cmd, request, NFS_LOCK_NEW);
 out:
 	request->fl_flags = fl_flags;
 	return status;
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index b6a6953c0f095..e5c3b620a6099 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -422,6 +422,7 @@ struct nfs_lock_args {
 	struct nfs_lowner	lock_owner;
 	unsigned char		block : 1;
 	unsigned char		reclaim : 1;
+	unsigned char		new_lock : 1;
 	unsigned char		new_lock_owner : 1;
 };
 
-- 
2.39.5