From patchwork Wed Dec 9 05:34:55 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 7804561 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 A7165BEEE1 for ; Wed, 9 Dec 2015 05:36:08 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C971A204D2 for ; Wed, 9 Dec 2015 05:36:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2488204B0 for ; Wed, 9 Dec 2015 05:36:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753210AbbLIFgE (ORCPT ); Wed, 9 Dec 2015 00:36:04 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:46502 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752020AbbLIFe6 (ORCPT ); Wed, 9 Dec 2015 00:34:58 -0500 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.76 #1 (Red Hat Linux)) id 1a6XOy-0005MB-Lp; Wed, 09 Dec 2015 05:34:56 +0000 From: Al Viro To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Neil Brown , linux-fsdevel@vger.kernel.org Subject: [PATCH v2 11/11] teach nfs_get_link() to work in RCU mode Date: Wed, 9 Dec 2015 05:34:55 +0000 Message-Id: <1449639295-20512-11-git-send-email-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <20151209053209.GV20997@ZenIV.linux.org.uk> References: <20151209053209.GV20997@ZenIV.linux.org.uk> 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 From: Al Viro based upon the corresponding patch from Neil's March patchset, again with kmap-related horrors removed. Signed-off-by: Al Viro --- fs/nfs/inode.c | 21 +++++++++++++++++++++ fs/nfs/symlink.c | 30 ++++++++++++++++++++---------- include/linux/nfs_fs.h | 1 + 3 files changed, 42 insertions(+), 10 deletions(-) diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index ae9aa0b..aa828e8 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -1087,6 +1087,27 @@ static bool nfs_mapping_need_revalidate_inode(struct inode *inode) || NFS_STALE(inode); } +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; +} + /** * __nfs_revalidate_mapping - Revalidate the pagecache * @inode - pointer to host inode diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c index 8ade8a8..95c69af 100644 --- a/fs/nfs/symlink.c +++ b/fs/nfs/symlink.c @@ -48,16 +48,26 @@ static const char *nfs_get_link(struct dentry *dentry, struct page *page; void *err; - if (!dentry) - return ERR_PTR(-ECHILD); - - err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping)); - if (err) - return err; - page = read_cache_page(&inode->i_data, 0, - (filler_t *)nfs_symlink_filler, inode); - if (IS_ERR(page)) - return ERR_CAST(page); + if (!dentry) { + err = ERR_PTR(nfs_revalidate_mapping_rcu(inode)); + if (err) + return err; + page = find_get_page(inode->i_mapping, 0); + if (!page) + return ERR_PTR(-ECHILD); + if (!PageUptodate(page)) { + put_page(page); + return ERR_PTR(-ECHILD); + } + } else { + err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping)); + if (err) + return err; + page = read_cache_page(&inode->i_data, 0, + (filler_t *)nfs_symlink_filler, inode); + if (IS_ERR(page)) + return ERR_CAST(page); + } *cookie = page; return page_address(page); } diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index c0e9614..37a3d29 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -359,6 +359,7 @@ 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_revalidate_mapping_protected(struct inode *inode, struct address_space *mapping); extern int nfs_setattr(struct dentry *, struct iattr *); extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);