[PATCH Version-2 10/12] NFSD: allow inter server COPY to have a STALE source server fh

[<andros@netapp.com>]

From: Andy Adamson <andros@netapp.com>

The inter server to server COPY source server filehandle
is guaranteed to be stale as the COPY is sent to the destination
server.

Signed-off-by: Andy Adamson <andros@netapp.com>
---
 fs/nfsd/nfs4proc.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 fs/nfsd/nfs4xdr.c  | 26 +++++++++++++++++++++++++-
 fs/nfsd/nfsd.h     |  2 ++
 fs/nfsd/xdr4.h     |  4 ++++
 4 files changed, 77 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 244c060..8e9bae6 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -510,11 +510,19 @@ static __be32
 nfsd4_putfh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	    struct nfsd4_putfh *putfh)
 {
+	__be32 ret;
+
 	fh_put(&cstate->current_fh);
 	cstate->current_fh.fh_handle.fh_size = putfh->pf_fhlen;
 	memcpy(&cstate->current_fh.fh_handle.fh_base, putfh->pf_fhval,
 	       putfh->pf_fhlen);
-	return fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_BYPASS_GSS);
+	ret = fh_verify(rqstp, &cstate->current_fh, 0, NFSD_MAY_BYPASS_GSS);
+	if (ret == nfserr_stale && HAS_CSTATE_FLAG(cstate, NO_VERIFY_FH)) {
+		CLEAR_CSTATE_FLAG(cstate, NO_VERIFY_FH);
+		SET_CSTATE_FLAG(cstate, IS_STALE_FH);
+		ret = 0;
+	}
+	return ret;
 }
 
 static __be32
@@ -547,6 +555,16 @@ static __be32
 nfsd4_savefh(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	     void *arg)
 {
+	/**
+	* This is either an inter COPY (most likely) or an intra COPY with a
+	* stale file handle. If the latter, nfsd4_copy will reset the PUTFH to
+	* return nfserr_stale. No fh_dentry, just copy the file handle
+	* to use with the inter COPY READ.
+	*/
+	if (HAS_CSTATE_FLAG(cstate, IS_STALE_FH)) {
+		cstate->save_fh = cstate->current_fh;
+		return nfs_ok;
+	}
 	if (!cstate->current_fh.fh_dentry)
 		return nfserr_nofilehandle;
 
@@ -1081,6 +1099,13 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (status)
 		goto out;
 
+	/* Intra copy source fh is stale. PUTFH will fail with ESTALE */
+	if (HAS_CSTATE_FLAG(cstate, IS_STALE_FH)) {
+		CLEAR_CSTATE_FLAG(cstate, IS_STALE_FH);
+		cstate->status = nfserr_copy_stalefh;
+		goto out_put;
+	}
+
 	bytes = nfsd_copy_file_range(src, copy->cp_src_pos,
 			dst, copy->cp_dst_pos, copy->cp_count);
 
@@ -1095,6 +1120,7 @@ nfsd4_copy(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		status = nfs_ok;
 	}
 
+out_put:
 	fput(src);
 	fput(dst);
 out:
@@ -1791,6 +1817,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
 	struct nfsd4_compound_state *cstate = &resp->cstate;
 	struct svc_fh *current_fh = &cstate->current_fh;
 	struct svc_fh *save_fh = &cstate->save_fh;
+	int		i;
 	__be32		status;
 
 	svcxdr_init_encode(rqstp, resp);
@@ -1823,6 +1850,12 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
 		goto encode_op;
 	}
 
+	/* NFSv4.2 COPY source file handle may be from a different server */
+	for (i = 0; i < args->opcnt; i++) {
+		op = &args->ops[i];
+		if (op->opnum == OP_COPY)
+			SET_CSTATE_FLAG(cstate, NO_VERIFY_FH);
+	}
 	while (!status && resp->opcnt < args->opcnt) {
 		op = &args->ops[resp->opcnt++];
 
@@ -1842,6 +1875,9 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
 
 		opdesc = OPDESC(op);
 
+		if (HAS_CSTATE_FLAG(cstate, IS_STALE_FH))
+			goto call_op;
+
 		if (!current_fh->fh_dentry) {
 			if (!(opdesc->op_flags & ALLOWED_WITHOUT_FH)) {
 				op->status = nfserr_nofilehandle;
@@ -1876,6 +1912,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
 
 		if (opdesc->op_get_currentstateid)
 			opdesc->op_get_currentstateid(cstate, &op->u);
+call_op:
 		op->status = opdesc->op_func(rqstp, cstate, &op->u);
 
 		if (!op->status) {
@@ -1896,6 +1933,14 @@ encode_op:
 			status = op->status;
 			goto out;
 		}
+		/* Only from intra COPY */
+		if (cstate->status == nfserr_copy_stalefh) {
+			dprintk("%s NFS4.2 intra COPY stale src filehandle\n",
+				__func__);
+			status = nfserr_stale;
+			nfsd4_adjust_encode(resp);
+			goto out;
+		}
 		if (op->status == nfserr_replay_me) {
 			op->replay = &cstate->replay_owner->so_replay;
 			nfsd4_encode_replay(&resp->xdr, op);
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index f4bb29d..30ec499 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -4581,15 +4581,28 @@ __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 respsize)
 	return nfserr_rep_too_big;
 }
 
+/** Rewind the encoding to return nfserr_stale on the PUTFH
+ * in this failed Intra COPY compound
+ */
+void
+nfsd4_adjust_encode(struct nfsd4_compoundres *resp)
+{
+	__be32 *p;
+
+	p = resp->cstate.putfh_errp;
+	*p++ = nfserr_stale;
+}
+
 void
 nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
 {
 	struct xdr_stream *xdr = &resp->xdr;
 	struct nfs4_stateowner *so = resp->cstate.replay_owner;
+	struct nfsd4_compound_state *cstate = &resp->cstate;
 	struct svc_rqst *rqstp = resp->rqstp;
 	int post_err_offset;
 	nfsd4_enc encoder;
-	__be32 *p;
+	__be32 *p, *statp;
 
 	p = xdr_reserve_space(xdr, 8);
 	if (!p) {
@@ -4598,9 +4611,20 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op)
 	}
 	*p++ = cpu_to_be32(op->opnum);
 	post_err_offset = xdr->buf->len;
+	statp = p;
 
 	if (op->opnum == OP_ILLEGAL)
 		goto status;
+
+	/** This is a COPY compound with a stale source server file handle.
+	 * If OP_COPY processing determines that this is an intra server to
+	 * server COPY, then this PUTFH should return nfserr_ stale so the
+	 * putfh_errp will be set to nfserr_stale. If this is an inter server
+	 * to server COPY, ignore the nfserr_stale.
+	 */
+	if (op->opnum == OP_PUTFH && HAS_CSTATE_FLAG(cstate, IS_STALE_FH))
+		cstate->putfh_errp = statp;
+
 	BUG_ON(op->opnum < 0 || op->opnum >= ARRAY_SIZE(nfsd4_enc_ops) ||
 	       !nfsd4_enc_ops[op->opnum]);
 	encoder = nfsd4_enc_ops[op->opnum];
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 9446849..341ff89 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -272,6 +272,8 @@ void		nfsd_lockd_shutdown(void);
 #define	nfserr_replay_me	cpu_to_be32(11001)
 /* nfs41 replay detected */
 #define	nfserr_replay_cache	cpu_to_be32(11002)
+/* nfs42 intra copy failed with nfserr_stale */
+#define nfserr_copy_stalefh	cpu_to_be32(1103)
 
 /* Check for dir entries '.' and '..' */
 #define isdotent(n, l)	(l < 3 && n[0] == '.' && (l == 1 || n[1] == '.'))
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 38fcb4f..aa94295 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -45,6 +45,8 @@
 
 #define CURRENT_STATE_ID_FLAG (1<<0)
 #define SAVED_STATE_ID_FLAG (1<<1)
+#define NO_VERIFY_FH (1<<2)
+#define IS_STALE_FH  (1<<3)
 
 #define SET_CSTATE_FLAG(c, f) ((c)->sid_flags |= (f))
 #define HAS_CSTATE_FLAG(c, f) ((c)->sid_flags & (f))
@@ -63,6 +65,7 @@ struct nfsd4_compound_state {
 	size_t			iovlen;
 	u32			minorversion;
 	__be32			status;
+	__be32			*putfh_errp;
 	stateid_t	current_stateid;
 	stateid_t	save_stateid;
 	/* to indicate current and saved state id presents */
@@ -705,6 +708,7 @@ int nfs4svc_decode_compoundargs(struct svc_rqst *, __be32 *,
 int nfs4svc_encode_compoundres(struct svc_rqst *, __be32 *,
 		struct nfsd4_compoundres *);
 __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *, u32);
+void nfsd4_adjust_encode(struct nfsd4_compoundres *);
 void nfsd4_encode_operation(struct nfsd4_compoundres *, struct nfsd4_op *);
 void nfsd4_encode_replay(struct xdr_stream *xdr, struct nfsd4_op *op);
 __be32 nfsd4_encode_fattr_to_buf(__be32 **p, int words,
-- 
1.8.3.1