pnfs: serialize LAYOUTGET(openstateid)

We shouldn't send a LAYOUTGET(openstateid) unless all outstanding RPCs
using the previous stateid are completed.  This requires choosing the
stateid to encode earlier, so we can abort if one is not available (we
want to use the open stateid, but a LAYOUTGET is already out using
it), and adding a count of the number of outstanding rpc calls using
layout state (which for now consist solely of LAYOUTGETs).

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 5bee453d36d..a3549ce72ab 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5304,6 +5304,12 @@ nfs4_layoutget_prepare(struct rpc_task *task, void *calldata)
 	if (nfs4_setup_sequence(server, &lgp->args.seq_args,
 				&lgp->res.seq_res, 0, task))
 		return;
+	if (pnfs_choose_layoutget_stateid(&lgp->args.stateid,
+					  NFS_I(lgp->args.inode)->layout,
+					  lgp->args.ctx->state)) {
+		rpc_exit(task, NFS4_OK);
+		return;
+	}
 	rpc_call_start(task);
 }
 
@@ -5338,7 +5344,6 @@ static void nfs4_layoutget_release(void *calldata)
 	struct nfs4_layoutget *lgp = calldata;
 
 	dprintk("--> %s\n", __func__);
-	put_layout_hdr(lgp->args.inode);
 	if (lgp->res.layout.buf != NULL)
 		free_page((unsigned long) lgp->res.layout.buf);
 	put_nfs_open_context(lgp->args.ctx);