[08/15] pnfs: serialize LAYOUTGET(openstateid)

Commit Message

Fred Isaman Jan. 6, 2011, 11:36 a.m. UTC

None

Patch

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 5bee453..a3549ce 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);
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 4e28242..3cbdd0c 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1787,7 +1787,6 @@  encode_layoutget(struct xdr_stream *xdr,
 		      const struct nfs4_layoutget_args *args,
 		      struct compound_hdr *hdr)
 {
-	nfs4_stateid stateid;
 	__be32 *p;
 
 	p = reserve_space(xdr, 44 + NFS4_STATEID_SIZE);
@@ -1798,9 +1797,7 @@  encode_layoutget(struct xdr_stream *xdr,
 	p = xdr_encode_hyper(p, args->range.offset);
 	p = xdr_encode_hyper(p, args->range.length);
 	p = xdr_encode_hyper(p, args->minlength);
-	pnfs_choose_layoutget_stateid(&stateid, NFS_I(args->inode)->layout,
-				args->ctx->state);
-	p = xdr_encode_opaque_fixed(p, &stateid.data, NFS4_STATEID_SIZE);
+	p = xdr_encode_opaque_fixed(p, &args->stateid.data, NFS4_STATEID_SIZE);
 	*p = cpu_to_be32(args->maxcount);
 
 	dprintk("%s: 1st type:0x%x iomode:%d off:%lu len:%lu mc:%d\n",
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 212cbc2..59ed68b 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -371,6 +371,14 @@  pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo,
 		memcpy(&lo->plh_stateid, &new->stateid, sizeof(new->stateid));
 }
 
+/* lget is set to 1 if called from inside send_layoutget call chain */
+static bool
+pnfs_layoutgets_blocked(struct pnfs_layout_hdr *lo, int lget)
+{
+	return (list_empty(&lo->plh_segs) &&
+		 (atomic_read(&lo->plh_outstanding) > lget));
+}
+
 int
 pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
 			      struct nfs4_state *open_state)
@@ -379,7 +387,9 @@  pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
 
 	dprintk("--> %s\n", __func__);
 	spin_lock(&lo->plh_inode->i_lock);
-	if (list_empty(&lo->plh_segs)) {
+	if (pnfs_layoutgets_blocked(lo, 1)) {
+		status = -EAGAIN;
+	} else if (list_empty(&lo->plh_segs)) {
 		int seq;
 
 		do {
@@ -414,10 +424,8 @@  send_layoutget(struct pnfs_layout_hdr *lo,
 
 	BUG_ON(ctx == NULL);
 	lgp = kzalloc(sizeof(*lgp), GFP_KERNEL);
-	if (lgp == NULL) {
-		put_layout_hdr(lo->plh_inode);
+	if (lgp == NULL)
 		return NULL;
-	}
 	lgp->args.minlength = NFS4_MAX_UINT64;
 	lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
 	lgp->args.range.iomode = iomode;
@@ -613,10 +621,16 @@  pnfs_update_layout(struct inode *ino,
 	if (test_bit(lo_fail_bit(iomode), &nfsi->layout->plh_flags))
 		goto out_unlock;
 
-	get_layout_hdr_locked(lo); /* Matched in nfs4_layoutget_release */
+	if (pnfs_layoutgets_blocked(lo, 0))
+		goto out_unlock;
+	atomic_inc(&lo->plh_outstanding);
+
+	get_layout_hdr_locked(lo);
 	spin_unlock(&ino->i_lock);
 
 	lseg = send_layoutget(lo, ctx, iomode);
+	atomic_dec(&lo->plh_outstanding);
+	put_layout_hdr(ino);
 out:
 	dprintk("%s end, state 0x%lx lseg %p\n", __func__,
 		nfsi->layout->plh_flags, lseg);
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 787253e..698380d 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -69,6 +69,7 @@  struct pnfs_layout_hdr {
 	struct list_head	plh_layouts;   /* other client layouts */
 	struct list_head	plh_segs;      /* layout segments list */
 	nfs4_stateid		plh_stateid;
+	atomic_t		plh_outstanding; /* number of RPCs out */
 	unsigned long		plh_flags;
 	struct inode		*plh_inode;
 };
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 8fcc542..83d36d3 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -208,6 +208,7 @@  struct nfs4_layoutget_args {
 	struct inode *inode;
 	struct nfs_open_context *ctx;
 	struct nfs4_sequence_args seq_args;
+	nfs4_stateid stateid;
 };
 
 struct nfs4_layoutget_res {