[PATCH] NFS: fix the synchronous READ/WRITE bugs

  - Use correct credentials in the NFSv4 synchronous read/write code.
  - Return correct number of read bytes in the NFSv4 synchronous read code.
  - SunRPC XDR fix: NFSv4 reads when caller requests a non-word aligned
    number of bytes was broken.

fs/nfs/nfs4proc.c

@@ -1038,7 +1038,6 @@ nfs4_proc_read(struct nfs_read_data *rdata, struct file *filp)
 		.rpc_proc	= &nfs4_procedures[NFSPROC4_CLNT_READ],
 		.rpc_argp	= &rdata->args,
 		.rpc_resp	= &rdata->res,
-		.rpc_cred	= rdata->cred,
 	};
 	unsigned long timestamp = jiffies;
 	int status;
@@ -1053,8 +1052,11 @@ nfs4_proc_read(struct nfs_read_data *rdata, struct file *filp)
 		struct nfs4_state *state;
 		state = (struct nfs4_state *)filp->private_data;
 		memcpy(&rdata->args.stateid, &state->stateid, sizeof(rdata->args.stateid));
-	} else
+		msg.rpc_cred = state->owner->so_cred;
+	} else {
 		memcpy(&rdata->args.stateid, &zero_stateid, sizeof(rdata->args.stateid));
+		msg.rpc_cred = NFS_I(inode)->mm_cred;
+	}
 
 	fattr->valid = 0;
 	status = rpc_call_sync(server->client, &msg, flags);
@@ -1079,7 +1081,6 @@ nfs4_proc_write(struct nfs_write_data *wdata, struct file *filp)
 		.rpc_proc	= &nfs4_procedures[NFSPROC4_CLNT_WRITE],
 		.rpc_argp	= &wdata->args,
 		.rpc_resp	= &wdata->res,
-		.rpc_cred	= wdata->cred,
 	};
 	int status;
 
@@ -1093,11 +1094,15 @@ nfs4_proc_write(struct nfs_write_data *wdata, struct file *filp)
 		struct nfs4_state *state;
 		state = (struct nfs4_state *)filp->private_data;
 		memcpy(&wdata->args.stateid, &state->stateid, sizeof(wdata->args.stateid));
-	} else
+		msg.rpc_cred = state->owner->so_cred;
+	} else {
 		memcpy(&wdata->args.stateid, &zero_stateid, sizeof(wdata->args.stateid));
+		msg.rpc_cred = NFS_I(inode)->mm_cred;
+	}
 
 	fattr->valid = 0;
 	status = rpc_call_sync(server->client, &msg, rpcflags);
+	NFS_CACHEINV(inode);
 	dprintk("NFS reply write: %d\n", status);
 	return status;
 }

fs/nfs/nfs4xdr.c

@@ -2323,6 +2323,8 @@ nfs4_xdr_dec_read(struct rpc_rqst *rqstp, uint32_t *p, struct nfs_readres *res)
 	status = decode_read_getattr(&xdr, res->fattr);
 	if (!status)
 		status = -nfs_stat_to_errno(hdr.status);
+	if (!status)
+		status = res->count;
 out:
 	return status;
 }

net/sunrpc/xdr.c

@@ -715,6 +715,7 @@ xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
 	struct xdr_buf *buf = xdr->buf;
 	struct iovec *iov;
 	ssize_t shift;
+	int padding;
 
 	/* Realign pages to current pointer position */
 	iov  = buf->head;
@@ -723,10 +724,10 @@ xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
 		xdr_shrink_bufhead(buf, shift);
 
 	/* Truncate page data and move it into the tail */
-	len = XDR_QUADLEN(len) << 2;
 	if (buf->page_len > len)
 		xdr_shrink_pagelen(buf, buf->page_len - len);
+	padding = (XDR_QUADLEN(len) << 2) - len;
 	xdr->iov = iov = buf->tail;
-	xdr->p = (uint32_t *)iov->iov_base;
+	xdr->p = (uint32_t *)((char *)iov->iov_base + padding);
 	xdr->end = (uint32_t *)((char *)iov->iov_base + iov->iov_len);
 }