From patchwork Mon Mar 16 04:43:20 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 6015251 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 592D1BF90F for ; Mon, 16 Mar 2015 04:45:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8C4A7203DA for ; Mon, 16 Mar 2015 04:45:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A0A5C202F8 for ; Mon, 16 Mar 2015 04:45:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751338AbbCPEpe (ORCPT ); Mon, 16 Mar 2015 00:45:34 -0400 Received: from cantor2.suse.de ([195.135.220.15]:56300 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753415AbbCPEpc (ORCPT ); Mon, 16 Mar 2015 00:45:32 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 37C1FABB5; Mon, 16 Mar 2015 04:45:31 +0000 (UTC) From: NeilBrown To: Al Viro Date: Mon, 16 Mar 2015 15:43:20 +1100 Subject: [PATCH 13/13] NFS: support LOOKUP_RCU in nfs_follow_link. Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <20150316044320.23648.44328.stgit@notabene.brown> In-Reply-To: <20150316043602.23648.52734.stgit@notabene.brown> References: <20150316043602.23648.52734.stgit@notabene.brown> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable 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 If the inode is valid and the page has been read in, then we can follow a link in RCU-walk. Signed-off-by: NeilBrown --- fs/nfs/inode.c | 22 ++++++++++++++++++++++ fs/nfs/symlink.c | 20 ++++++++++++++++++-- include/linux/nfs_fs.h | 1 + 3 files changed, 41 insertions(+), 2 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 83107be3dd01..80f192405102 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -1123,6 +1123,28 @@ out: return ret; } +int nfs_revalidate_mapping_rcu(struct inode *inode) +{ + struct nfs_inode *nfsi = NFS_I(inode); + unsigned long *bitlock = &nfsi->flags; + int ret = 0; + + if (IS_SWAPFILE(inode)) + goto out; + if (nfs_mapping_need_revalidate_inode(inode)) { + ret = -ECHILD; + goto out; + } + spin_lock(&inode->i_lock); + if (test_bit(NFS_INO_INVALIDATING, bitlock) || + (nfsi->cache_validity & NFS_INO_INVALID_DATA)) + ret = -ECHILD; + spin_unlock(&inode->i_lock); +out: + return ret; +} + + static unsigned long nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr) { struct nfs_inode *nfsi = NFS_I(inode); diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c index 43e43d2c8c5b..849bef4b0ae1 100644 --- a/fs/nfs/symlink.c +++ b/fs/nfs/symlink.c @@ -49,8 +49,24 @@ static void *nfs_follow_link(struct dentry *dentry, int flags) struct page *page; void *err; - if (flags & LOOKUP_RCU) - return ERR_PTR(-ECHILD); + if (flags & LOOKUP_RCU) { + err = ERR_PTR(nfs_revalidate_mapping_rcu(inode)); + if (err) + goto read_failed; + page = find_get_page(inode->i_mapping, 0); + if (page && + (!PageUptodate(page) || PageHighMem(page))) { + put_page(page); + page = NULL; + } + if (!page) { + err = ERR_PTR(-ECHILD); + goto read_failed; + } + nd_set_link(page_address(page)); + page = (void*)((unsigned long)page | 1); + return page; + } err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping)); if (err) goto read_failed; diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 2f77e0c651c8..78c2f812eaeb 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -355,6 +355,7 @@ extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode); extern int nfs_revalidate_inode_rcu(struct nfs_server *server, struct inode *inode); extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *); extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping); +extern int nfs_revalidate_mapping_rcu(struct inode *inode); extern int nfs_setattr(struct dentry *, struct iattr *); extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr); extern void nfs_setsecurity(struct inode *inode, struct nfs_fattr *fattr,