NFSv4: add zero-copy write support for nfsv4

We now have zero-cop write for both NFSv3 and v4. We also have (almost) zero-copy read for both NFSv3 and v4. Signed-off-by: Ronnie Sahlberg <[email protected]>
sahlberg · Nov 17, 2023 · ab0216a · ab0216a
1 parent 6dc235a
commit ab0216a
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Showing 9 changed files with 129 additions and 6 deletions.
diff --git a/README b/README
@@ -34,7 +34,6 @@ TODOs:
 * Fragmentation is currently broken
 * All high level async functions (nfs_*async) should return a handle so that
   they can be cancelled.
-* Make zero-copy work for NFS4 writes
 
 LIBNFS is a client library for accessing NFS shares over a network.
 

diff --git a/include/nfsc/libnfs-raw.h b/include/nfsc/libnfs-raw.h
@@ -2362,6 +2362,7 @@ rpc_nfs4_null_async(struct rpc_context *rpc, rpc_cb cb,
 
 /*
  * Call NFS4/COMPOUND
+ *
  * Function returns
  *  pdu : The command was queued successfully. The callback will be invoked once
  *        the command completes.
@@ -2375,6 +2376,7 @@ rpc_nfs4_null_async(struct rpc_context *rpc, rpc_cb cb,
  *                      data is the error string.
  * RPC_STATUS_CANCEL  : The command was cancelled.
  *                      data is NULL.
+ * This function can NOT be used for compounds that contain OP_READ or OP_WRITE.
  */
 struct COMPOUND4args;
 EXTERN struct rpc_pdu *
@@ -2397,6 +2399,7 @@ rpc_nfs4_compound_async(struct rpc_context *rpc, rpc_cb cb,
  *                      data is the error string.
  * RPC_STATUS_CANCEL  : The command was cancelled.
  *                      data is NULL.
+ * This function can NOT be used for compounds that contain OP_READ or OP_WRITE.
  */
 struct COMPOUND4args;
 EXTERN struct rpc_pdu *
@@ -2421,12 +2424,41 @@ rpc_nfs4_compound_async2(struct rpc_context *rpc, rpc_cb cb,
  *                      data is the error string.
  * RPC_STATUS_CANCEL  : The command was cancelled.
  *                      data is NULL.
+ * If the compound contains OP_READ you must use this function and not
+ * rpc_nfs4_compound_async()
+ * The OP_READ must be the last operation in the compound.
  */
 EXTERN struct rpc_pdu *
 rpc_nfs4_read_async(struct rpc_context *rpc, rpc_cb cb,
                     void *buf, size_t count,
                     struct COMPOUND4args *args,
                     void *private_data);
+
+/*
+ * Call NFS4/COMPOUND for write operations
+ *
+ * Function returns
+ *  0 : The command was queued successfully. The callback will be invoked once
+ *      the command completes.
+ * <0 : An error occured when trying to queue the command.
+ *      The callback will not be invoked.
+ *
+ * When the callback is invoked, status indicates the result:
+ * RPC_STATUS_SUCCESS : We got a successful response from the server.
+ *                      data is COMPOUND4res *.
+ * RPC_STATUS_ERROR   : The command failed with an error.
+ *                      data is the error string.
+ * RPC_STATUS_CANCEL  : The command was cancelled.
+ *                      data is NULL.
+ * If the compound contains OP_WRITE you must use this function and not
+ * rpc_nfs4_compound_async()
+ * The OP_WRITE must be the last operation in the compound.
+ */
+EXTERN struct rpc_pdu *
+rpc_nfs4_write_async(struct rpc_context *rpc, rpc_cb cb,
+                     const void *buf, size_t count,
+                     struct COMPOUND4args *args,
+                     void *private_data);
 
 /*
  * Call <generic>/NULL

diff --git a/lib/libnfs-win32.def b/lib/libnfs-win32.def
@@ -215,6 +215,7 @@ rpc_nfs4_compound_async
 rpc_nfs4_compound_async2
 rpc_nfs4_null_async
 rpc_nfs4_read_async
+rpc_nfs4_write_async
 rpc_nlm4_null_async
 rpc_nlm4_test_async
 rpc_nlm4_lock_async

diff --git a/lib/nfs_v4.c b/lib/nfs_v4.c
@@ -3018,8 +3018,8 @@ nfs4_pwrite_async_internal(struct nfs_context *nfs, struct nfsfh *nfsfh,
         args.argarray.argarray_len = i;
         args.argarray.argarray_val = op;
 
-        if (rpc_nfs4_compound_async2(nfs->rpc, nfs4_pwrite_cb, &args,
-                                    data, count) == NULL) {
+        if (rpc_nfs4_write_async(nfs->rpc, nfs4_pwrite_cb, buf, count,
+                                 &args, data) == NULL) {
                 nfs_set_error(nfs, "PWRITE "
                         "failed: %s", rpc_get_error(nfs->rpc));
                 free_nfs4_cb_data(data);

diff --git a/nfs/nfs.c b/nfs/nfs.c
@@ -35,8 +35,6 @@
 #include "libnfs-private.h"
 #include "libnfs-raw-nfs.h"
 
-uint32_t zero_padding;
-
 char *nfsstat3_to_str(int error)
 {
 	switch (error) {
@@ -321,6 +319,7 @@ struct rpc_pdu *rpc_nfs3_write_async(struct rpc_context *rpc, rpc_cb cb,
 {
 	struct rpc_pdu *pdu;
         int start;
+        static uint32_t zero_padding;
 
 	pdu = rpc_allocate_pdu2(rpc, NFS_PROGRAM, NFS_V3, NFS3_WRITE, cb, private_data, (zdrproc_t)zdr_WRITE3res, sizeof(WRITE3res), 0);
 	if (pdu == NULL) {

diff --git a/nfs4/Makefile.am b/nfs4/Makefile.am
@@ -39,4 +39,5 @@ compile_rpc:
 -e "s/register int32_t \*buf;//" \
 -e "s/int i;//" >> libnfs-raw-nfs4.c
 	sed -z -i -e "s/zdr_READ4resok/zzdr_READ4resok/" libnfs-raw-nfs4.c
+	sed -z -i -e "s/zdr_WRITE4args/zzdr_WRITE4args/" libnfs-raw-nfs4.c
 	cat libnfs-raw-nfs4.c.fragment >>libnfs-raw-nfs4.c
diff --git a/nfs4/libnfs-raw-nfs4.c b/nfs4/libnfs-raw-nfs4.c
@@ -2705,7 +2705,7 @@ zdr_stable_how4 (ZDR *zdrs, stable_how4 *objp)
 }
 
 uint32_t
-zdr_WRITE4args (ZDR *zdrs, WRITE4args *objp)
+zzdr_WRITE4args (ZDR *zdrs, WRITE4args *objp)
 {
 
 
@@ -4595,3 +4595,14 @@ zdr_READ4resok (ZDR *zdrs, READ4resok *objp)
 	return TRUE;
 }
 
+uint32_t
+zdr_WRITE4args (ZDR *zdrs, WRITE4args *objp)
+{
+	 if (!zdr_stateid4 (zdrs, &objp->stateid))
+		 return FALSE;
+	 if (!zdr_offset4 (zdrs, &objp->offset))
+		 return FALSE;
+	 if (!zdr_stable_how4 (zdrs, &objp->stable))
+		 return FALSE;
+	return TRUE;
+}
diff --git a/nfs4/libnfs-raw-nfs4.c.fragment b/nfs4/libnfs-raw-nfs4.c.fragment
@@ -13,3 +13,14 @@ zdr_READ4resok (ZDR *zdrs, READ4resok *objp)
 	return TRUE;
 }
 
+uint32_t
+zdr_WRITE4args (ZDR *zdrs, WRITE4args *objp)
+{
+	 if (!zdr_stateid4 (zdrs, &objp->stateid))
+		 return FALSE;
+	 if (!zdr_offset4 (zdrs, &objp->offset))
+		 return FALSE;
+	 if (!zdr_stable_how4 (zdrs, &objp->stable))
+		 return FALSE;
+	return TRUE;
+}
diff --git a/nfs4/nfs4.c b/nfs4/nfs4.c
@@ -278,3 +278,72 @@ struct rpc_pdu *rpc_nfs4_read_async(struct rpc_context *rpc, rpc_cb cb,
 
 	return pdu;
 }
+
+struct rpc_pdu *rpc_nfs4_write_async(struct rpc_context *rpc, rpc_cb cb,
+                                     const void *buf, size_t count,
+                                     struct COMPOUND4args *args,
+                                     void *private_data)
+{
+	struct rpc_pdu *pdu;
+        int start;
+        uint32_t len;
+        static uint32_t zero_padding;
+
+	pdu = rpc_allocate_pdu2(rpc, NFS4_PROGRAM, NFS_V4, NFSPROC4_COMPOUND,
+                               cb, private_data, (zdrproc_t)zdr_COMPOUND4res,
+                                sizeof(COMPOUND4res), 0);
+	if (pdu == NULL) {
+		rpc_set_error(rpc, "Out of memory. Failed to allocate pdu for "
+                              "NFS4/COMPOUND call");
+		return NULL;
+	}
+
+        start = zdr_getpos(&pdu->zdr);
+
+	if (zdr_COMPOUND4args(&pdu->zdr,  args) == 0) {
+		rpc_set_error(rpc, "ZDR error: Failed to encode COMPOUND4args");
+		rpc_free_pdu(rpc, pdu);
+		return NULL;
+	}
+
+        /* Add an iovector for the COMPOUND4/.../WRITE4 header */
+        if (rpc_add_iovector(rpc, &pdu->out, &pdu->outdata.data[start + 4],
+                             zdr_getpos(&pdu->zdr) - start, NULL) < 0) {
+		rpc_free_pdu(rpc, pdu);
+		return NULL;
+        }
+
+        /* Add an iovector for the length of the byte/array blob */
+        start = zdr_getpos(&pdu->zdr);
+        len = count;
+        zdr_u_int(&pdu->zdr, &len);
+        if (rpc_add_iovector(rpc, &pdu->out, &pdu->outdata.data[start + 4],
+                             4, NULL) < 0) {
+		rpc_free_pdu(rpc, pdu);
+		return NULL;
+        }
+
+        /* Add an iovector for the data itself */
+        if (rpc_add_iovector(rpc, &pdu->out, buf, count, NULL) < 0) {
+		rpc_free_pdu(rpc, pdu);
+		return NULL;
+        }
+
+        /* We may need to pad this to 4 byte boundary */
+        if (count & 0x03) {
+                if (rpc_add_iovector(rpc, &pdu->out, (char *)&zero_padding,
+                                     4 - count & 0x03,
+                                     NULL) < 0) {
+                        rpc_free_pdu(rpc, pdu);
+                        return NULL;
+                }
+        }
+
+	if (rpc_queue_pdu(rpc, pdu) != 0) {
+		rpc_set_error(rpc, "Out of memory. Failed to queue pdu for "
+                              "NFS4/COMPOUND4 call");
+		return NULL;
+	}
+
+	return pdu;
+}