nfscl: Add a LayoutError RPC for NFSv4.2 pNFS mounts

If a pNFS server's DS runs out of disk space, it replies
NFSERR_NOSPC to the client doing writing.  For the Linux
client, it then sends a LayoutError RPC to the MDS server to
tell it about the error.  This patch adds the same to the
FreeBSD NFSv4.2 pNFS client, to maintain Linux compatible
behaviour, particlularily for non-FreeBSD pNFS servers.

MFC after:	2 weeks

4 files changed, 70 insertions, 6 deletions

diff --git a/sys/fs/nfs/nfs_commonsubs.c b/sys/fs/nfs/nfs_commonsubs.c
index 073da425c20c..d3d572fe5a90 100644
--- a/sys/fs/nfs/nfs_commonsubs.c
+++ b/sys/fs/nfs/nfs_commonsubs.c
@@ -215,7 +215,7 @@ static struct nfsrv_lughash	*nfsgroupnamehash;
 static int nfs_bigreply[NFSV42_NPROCS] = { 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,
-    1, 0, 0, 1, 0, 0, 0 };
+    1, 0, 0, 1, 0, 0, 0, 0 };
 
 /* local functions */
 static int nfsrv_skipace(struct nfsrv_descript *nd, int *acesizep);
@@ -301,6 +301,7 @@ static struct {
 	{ NFSV4OP_BINDCONNTOSESS, 1, "BindConSess", 11, },
 	{ NFSV4OP_LOOKUP, 5, "LookupOpen", 10, },
 	{ NFSV4OP_DEALLOCATE, 2, "Deallocate", 10, },
+	{ NFSV4OP_LAYOUTERROR, 1, "LayoutError", 11, },
 };
 
 /*
@@ -309,7 +310,8 @@ static struct {
 static int nfs_bigrequest[NFSV42_NPROCS] = {
 	0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0
+	0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
+	0
 };
 
 /*
diff --git a/sys/fs/nfs/nfsport.h b/sys/fs/nfs/nfsport.h
index 64ba4d48b3f1..5dcce15f7f64 100644
--- a/sys/fs/nfs/nfsport.h
+++ b/sys/fs/nfs/nfsport.h
@@ -421,10 +421,13 @@
 /* Do an NFSv4.2 Deallocate. */
 #define	NFSPROC_DEALLOCATE	67
 
+/* Do an NFSv4.2 LayoutError. */
+#define	NFSPROC_LAYOUTERROR	68
+
 /*
  * Must be defined as one higher than the last NFSv4.2 Proc# above.
  */
-#define	NFSV42_NPROCS		68
+#define	NFSV42_NPROCS		69
 
 #endif	/* NFS_V3NPROCS */
 
@@ -453,7 +456,7 @@ struct nfsstatsv1 {
 	uint64_t	readlink_bios;
 	uint64_t	biocache_readdirs;
 	uint64_t	readdir_bios;
-	uint64_t	rpccnt[NFSV42_NPROCS + 12];
+	uint64_t	rpccnt[NFSV42_NPROCS + 11];
 	uint64_t	rpcretries;
 	uint64_t	srvrpccnt[NFSV42_NOPS + NFSV4OP_FAKENOPS + 15];
 	uint64_t	reserved_0;
@@ -518,7 +521,7 @@ struct nfsstatsov1 {
 	uint64_t	readlink_bios;
 	uint64_t	biocache_readdirs;
 	uint64_t	readdir_bios;
-	uint64_t	rpccnt[NFSV42_NPROCS + 1];
+	uint64_t	rpccnt[NFSV42_NPROCS];
 	uint64_t	rpcretries;
 	uint64_t	srvrpccnt[NFSV42_PURENOPS + NFSV4OP_FAKENOPS];
 	uint64_t	reserved_0;
diff --git a/sys/fs/nfs/nfsproto.h b/sys/fs/nfs/nfsproto.h
index 7ac7cdc3bacf..968cc6a41cc3 100644
--- a/sys/fs/nfs/nfsproto.h
+++ b/sys/fs/nfs/nfsproto.h
@@ -402,10 +402,13 @@
 /* Do an NFSv4.2 Deallocate. */
 #define	NFSPROC_DEALLOCATE	67
 
+/* Do an NFSv4.2 LayoutError. */
+#define	NFSPROC_LAYOUTERROR	68
+
 /*
  * Must be defined as one higher than the last NFSv4.2 Proc# above.
  */
-#define	NFSV42_NPROCS		68
+#define	NFSV42_NPROCS		69
 
 #endif	/* NFS_V3NPROCS */
 
diff --git a/sys/fs/nfsclient/nfs_clrpcops.c b/sys/fs/nfsclient/nfs_clrpcops.c
index f74493debd7c..f520743e8c32 100644
--- a/sys/fs/nfsclient/nfs_clrpcops.c
+++ b/sys/fs/nfsclient/nfs_clrpcops.c
@@ -149,6 +149,9 @@ static int nfsrpc_locku(struct nfsrv_descript *, struct nfsmount *,
     u_int32_t, struct ucred *, NFSPROC_T *, int);
 static int nfsrpc_setaclrpc(vnode_t, struct ucred *, NFSPROC_T *,
     struct acl *, nfsv4stateid_t *, void *);
+static int nfsrpc_layouterror(struct nfsmount *, uint8_t *, int, uint64_t,
+    uint64_t, nfsv4stateid_t *, struct ucred *, NFSPROC_T *, uint32_t,
+    uint32_t, char *);
 static int nfsrpc_getlayout(struct nfsmount *, vnode_t, struct nfsfh *, int,
     uint32_t, uint32_t *, nfsv4stateid_t *, uint64_t, struct nfscllayout **,
     struct ucred *, NFSPROC_T *);
@@ -5706,6 +5709,44 @@ nfsmout:
 }
 
 /*
+ * Do the NFSv4.2 LayoutError.
+ */
+static int
+nfsrpc_layouterror(struct nfsmount *nmp, uint8_t *fh, int fhlen, uint64_t offset,
+    uint64_t len, nfsv4stateid_t *stateidp, struct ucred *cred, NFSPROC_T *p,
+    uint32_t stat, uint32_t op, char *devid)
+{
+	uint32_t *tl;
+	struct nfsrv_descript nfsd, *nd = &nfsd;
+	int error;
+
+	nfscl_reqstart(nd, NFSPROC_LAYOUTERROR, nmp, fh, fhlen, NULL, NULL,
+	    0, 0);
+	NFSM_BUILD(tl, uint32_t *, 2 * NFSX_HYPER + NFSX_STATEID +
+	    NFSX_V4DEVICEID + 3 * NFSX_UNSIGNED);
+	txdr_hyper(offset, tl); tl += 2;
+	txdr_hyper(len, tl); tl += 2;
+	*tl++ = txdr_unsigned(stateidp->seqid);
+	*tl++ = stateidp->other[0];
+	*tl++ = stateidp->other[1];
+	*tl++ = stateidp->other[2];
+	*tl++ = txdr_unsigned(1);
+	NFSBCOPY(devid, tl, NFSX_V4DEVICEID);
+	tl += (NFSX_V4DEVICEID / NFSX_UNSIGNED);
+	*tl++ = txdr_unsigned(stat);
+	*tl = txdr_unsigned(op);
+	nd->nd_flag |= ND_USEGSSNAME;
+	error = newnfs_request(nd, nmp, NULL, &nmp->nm_sockreq, NULL, p, cred,
+	    NFS_PROG, NFS_VER4, NULL, 1, NULL, NULL);
+	if (error != 0)
+		return (error);
+	if (nd->nd_repstat != 0)
+		error = nd->nd_repstat;
+	m_freem(nd->nd_mrep);
+	return (error);
+}
+
+/*
  * Acquire a layout and devinfo, if possible. The caller must have acquired
  * a reference count on the nfsclclient structure before calling this.
  * Return the layout in lypp with a reference count on it, if successful.
@@ -6044,6 +6085,7 @@ nfscl_doiods(vnode_t vp, struct uio *uiop, int *iomode, int *must_commit,
 	size_t iovlen = 0;
 	off_t offs = 0;
 	ssize_t resid = 0;
+	uint32_t op;
 
 	if (!NFSHASPNFS(nmp) || nfscl_enablecallb == 0 || nfs_numnfscbd == 0 ||
 	    (np->n_flag & NNOLAYOUT) != 0)
@@ -6223,6 +6265,20 @@ nfscl_doiods(vnode_t vp, struct uio *uiop, int *iomode, int *must_commit,
 				NFSLOCKMNT(nmp);
 				nmp->nm_state |= NFSSTA_OPENMODE;
 				NFSUNLOCKMNT(nmp);
+			} else if ((error == NFSERR_NOSPC ||
+			    error == NFSERR_IO || error == NFSERR_NXIO) &&
+			    nmp->nm_minorvers == NFSV42_MINORVERSION) {
+				if (docommit != 0)
+					op = NFSV4OP_COMMIT;
+				else if (rwaccess == NFSV4OPEN_ACCESSREAD)
+					op = NFSV4OP_READ;
+				else
+					op = NFSV4OP_WRITE;
+				nfsrpc_layouterror(nmp, np->n_fhp->nfh_fh,
+				    np->n_fhp->nfh_len, off, xfer,
+				    &layp->nfsly_stateid, newcred, p, error, op,
+				    dip->nfsdi_deviceid);
+				error = EIO;
 			} else
 				error = EIO;
 			if (error == 0)