From patchwork Thu May 22 19:31:55 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bruce Fields X-Patchwork-Id: 4226101 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C748ABF90B for ; Thu, 22 May 2014 19:33:19 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EB1F22038C for ; Thu, 22 May 2014 19:33:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06D132038F for ; Thu, 22 May 2014 19:33:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752304AbaEVTdJ (ORCPT ); Thu, 22 May 2014 15:33:09 -0400 Received: from fieldses.org ([174.143.236.118]:43358 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752323AbaEVTce (ORCPT ); Thu, 22 May 2014 15:32:34 -0400 Received: from bfields by fieldses.org with local (Exim 4.76) (envelope-from ) id 1WnYj9-0006oQ-Ug; Thu, 22 May 2014 15:32:31 -0400 From: "J. Bruce Fields" To: linux-nfs@vger.kernel.org Cc: Christoph Hellwig , "J. Bruce Fields" Subject: [PATCH 20/52] nfsd4: "backfill" using write_bytes_to_xdr_buf Date: Thu, 22 May 2014 15:31:55 -0400 Message-Id: <1400787148-25941-21-git-send-email-bfields@redhat.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1400787148-25941-1-git-send-email-bfields@redhat.com> References: <1400787148-25941-1-git-send-email-bfields@redhat.com> Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: "J. Bruce Fields" Normally xdr encoding proceeds in a single pass from start of a buffer to end, but sometimes we have to write a few bytes to an earlier position. Use write_bytes_to_xdr_buf for these cases rather than saving a pointer to write to. We plan to rewrite xdr_reserve_space to handle encoding across page boundaries using a scratch buffer, and don't want to risk writing to a pointer that was contained in a scratch buffer. Also it will no longer be safe to calculate lengths by subtracting two pointers, so use xdr_buf offsets instead. Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4xdr.c | 45 ++++++++++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 19 deletions(-) diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c index c8435ba..14efc5d 100644 --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -1759,16 +1759,19 @@ static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep, char esc_exit) { __be32 *p; - __be32 *countp; + __be32 pathlen; + int pathlen_offset; int strlen, count=0; char *str, *end, *next; dprintk("nfsd4_encode_components(%s)\n", components); + + pathlen_offset = xdr->buf->len; p = xdr_reserve_space(xdr, 4); if (!p) return nfserr_resource; - countp = p; - WRITE32(0); /* We will fill this in with @count later */ + p++; /* We will fill this in with @count later */ + end = str = components; while (*end) { bool found_esc = false; @@ -1801,8 +1804,8 @@ static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep, end++; str = end; } - p = countp; - WRITE32(count); + pathlen = htonl(xdr->buf->len - pathlen_offset); + write_bytes_to_xdr_buf(xdr->buf, pathlen_offset, &pathlen, 4); return 0; } @@ -2054,7 +2057,8 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, struct kstatfs statfs; __be32 *p; int starting_len = xdr->buf->len; - __be32 *attrlenp; + int attrlen_offset; + __be32 attrlen; u32 dummy; u64 dummy64; u32 rdattr_err = 0; @@ -2159,10 +2163,12 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp, WRITE32(1); WRITE32(bmval0); } + + attrlen_offset = xdr->buf->len; p = xdr_reserve_space(xdr, 4); if (!p) goto out_resource; - attrlenp = p++; /* to be backfilled later */ + p++; /* to be backfilled later */ if (bmval0 & FATTR4_WORD0_SUPPORTED_ATTRS) { u32 word0 = nfsd_suppattrs0(minorversion); @@ -2534,7 +2540,8 @@ out_acl: WRITE32(NFSD_SUPPATTR_EXCLCREAT_WORD2); } - *attrlenp = htonl((char *)xdr->p - (char *)attrlenp - 4); + attrlen = htonl(xdr->buf->len - attrlen_offset - 4); + write_bytes_to_xdr_buf(xdr->buf, attrlen_offset, &attrlen, 4); status = nfs_ok; out: @@ -3664,15 +3671,16 @@ __be32 nfsd4_check_resp_size(struct nfsd4_compoundres *resp, u32 pad) 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 svc_rqst *rqstp = resp->rqstp; - __be32 *statp; + int post_err_offset; nfsd4_enc encoder; __be32 *p; RESERVE_SPACE(8); WRITE32(op->opnum); - statp = p++; /* to be backfilled at the end */ + post_err_offset = xdr->buf->len; if (op->opnum == OP_ILLEGAL) goto status; @@ -3698,20 +3706,19 @@ nfsd4_encode_operation(struct nfsd4_compoundres *resp, struct nfsd4_op *op) * bug if we had to do this on a non-idempotent op: */ warn_on_nonidempotent_op(op); - resp->xdr.p = statp + 1; + xdr_truncate_encode(xdr, post_err_offset); } if (so) { + int len = xdr->buf->len - post_err_offset; + so->so_replay.rp_status = op->status; - so->so_replay.rp_buflen = (char *)resp->xdr.p - - (char *)(statp+1); - memcpy(so->so_replay.rp_buf, statp+1, so->so_replay.rp_buflen); + so->so_replay.rp_buflen = len; + read_bytes_from_xdr_buf(xdr->buf, post_err_offset, + so->so_replay.rp_buf, len); } status: - /* - * Note: We write the status directly, instead of using WRITE32(), - * since it is already in network byte order. - */ - *statp = op->status; + /* Note that op->status is already in network byte order: */ + write_bytes_to_xdr_buf(xdr->buf, post_err_offset - 4, &op->status, 4); } /*