From patchwork Wed Dec 26 15:53:52 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Shilovsky X-Patchwork-Id: 1911181 Return-Path: X-Original-To: patchwork-cifs-client@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id C48273FC66 for ; Wed, 26 Dec 2012 15:53:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752779Ab2LZPxL (ORCPT ); Wed, 26 Dec 2012 10:53:11 -0500 Received: from mail-la0-f44.google.com ([209.85.215.44]:59201 "EHLO mail-la0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751538Ab2LZPxK (ORCPT ); Wed, 26 Dec 2012 10:53:10 -0500 Received: by mail-la0-f44.google.com with SMTP id d3so10973807lah.31 for ; Wed, 26 Dec 2012 07:53:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:sender:from:to:subject:date:message-id:x-mailer :in-reply-to:references; bh=1rvCpMcWlbHuhTRExlg+SgvYItiUcVYDXI6Cw4fFST8=; b=KkfSyhxH2BvFubgl15GQn5eh5g8S7H/Rn8Zbor22SUBv8uyVXx/rhEzktVI8tjqopt uXPv2fr413EzYpxbsCJSvNBq74jjFJf/EUKTk1McFSLYACouHZ7xCsu3OQ7E38Pmc8/b u+ddWYtJJ1f6gYOWZR+diNJt4Kurs1X7peKvRM68fyMwUlbKv9BIgxgh8Yrt5Xg+hmWx 8xweyqGLP/iOWv2s1qwLVWggUfpyvVnHY9Z28uqVZhHTM3viLdtS9f3V9t94WE1w+pgy TiixjLwaOvjQkHb/4ERTHVofCxPYcJC96C4NS1yeWNIJFyp+c5zz/F7ddJFC15y9AKmY A/VQ== X-Received: by 10.152.144.164 with SMTP id sn4mr25780669lab.57.1356537189154; Wed, 26 Dec 2012 07:53:09 -0800 (PST) Received: from workstation.localdomain (PPPoE-78-29-79-97.san.ru. [78.29.79.97]) by mx.google.com with ESMTPS id ee5sm9627016lbb.14.2012.12.26.07.53.07 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 26 Dec 2012 07:53:08 -0800 (PST) From: Pavel Shilovsky To: linux-cifs@vger.kernel.org Subject: [PATCH 1/3] Revert "CIFS: Fix write after setting a read lock for read oplock files" Date: Wed, 26 Dec 2012 19:53:52 +0400 Message-Id: <1356537234-11507-2-git-send-email-piastry@etersoft.ru> X-Mailer: git-send-email 1.7.12.4 In-Reply-To: <1356537234-11507-1-git-send-email-piastry@etersoft.ru> References: <1356537234-11507-1-git-send-email-piastry@etersoft.ru> Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org that solution has data races and can end up two identical writes to the server: when clientCanCacheAll value can be changed during the execution of __generic_file_aio_write. Signed-off-by: Pavel Shilovsky Acked-by: Jeff Layton --- fs/cifs/cifsfs.c | 1 - fs/cifs/cifsglob.h | 1 - fs/cifs/file.c | 94 ++++++++++++++++++------------------------------------ 3 files changed, 31 insertions(+), 65 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index f653835..de7f916 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -228,7 +228,6 @@ cifs_alloc_inode(struct super_block *sb) cifs_set_oplock_level(cifs_inode, 0); cifs_inode->delete_pending = false; cifs_inode->invalid_mapping = false; - cifs_inode->leave_pages_clean = false; cifs_inode->vfs_inode.i_blkbits = 14; /* 2**14 = CIFS_MAX_MSGSIZE */ cifs_inode->server_eof = 0; cifs_inode->uniqueid = 0; diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index aea1eec..dfab450 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1030,7 +1030,6 @@ struct cifsInodeInfo { bool clientCanCacheAll; /* read and writebehind oplock */ bool delete_pending; /* DELETE_ON_CLOSE is set */ bool invalid_mapping; /* pagecache is invalid */ - bool leave_pages_clean; /* protected by i_mutex, not set pages dirty */ unsigned long time; /* jiffies of last update of inode */ u64 server_eof; /* current file size on server -- protected by i_lock */ u64 uniqueid; /* server inode number */ diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 0a6677b..1b322d0 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2103,15 +2103,7 @@ static int cifs_write_end(struct file *file, struct address_space *mapping, } else { rc = copied; pos += copied; - /* - * When we use strict cache mode and cifs_strict_writev was run - * with level II oplock (indicated by leave_pages_clean field of - * CIFS_I(inode)), we can leave pages clean - cifs_strict_writev - * sent the data to the server itself. - */ - if (!CIFS_I(inode)->leave_pages_clean || - !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO)) - set_page_dirty(page); + set_page_dirty(page); } if (rc > 0) { @@ -2462,8 +2454,8 @@ ssize_t cifs_user_writev(struct kiocb *iocb, const struct iovec *iov, } static ssize_t -cifs_pagecache_writev(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos, bool cache_ex) +cifs_writev(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) { struct file *file = iocb->ki_filp; struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data; @@ -2485,12 +2477,8 @@ cifs_pagecache_writev(struct kiocb *iocb, const struct iovec *iov, server->vals->exclusive_lock_type, NULL, CIFS_WRITE_OP)) { mutex_lock(&inode->i_mutex); - if (!cache_ex) - cinode->leave_pages_clean = true; rc = __generic_file_aio_write(iocb, iov, nr_segs, - &iocb->ki_pos); - if (!cache_ex) - cinode->leave_pages_clean = false; + &iocb->ki_pos); mutex_unlock(&inode->i_mutex); } @@ -2517,62 +2505,42 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov, struct cifsFileInfo *cfile = (struct cifsFileInfo *) iocb->ki_filp->private_data; struct cifs_tcon *tcon = tlink_tcon(cfile->tlink); - ssize_t written, written2; + +#ifdef CONFIG_CIFS_SMB2 /* - * We need to store clientCanCacheAll here to prevent race - * conditions - this value can be changed during an execution - * of generic_file_aio_write. For CIFS it can be changed from - * true to false only, but for SMB2 it can be changed both from - * true to false and vice versa. So, we can end up with a data - * stored in the cache, not marked dirty and not sent to the - * server if this value changes its state from false to true - * after cifs_write_end. + * If we have an oplock for read and want to write a data to the file + * we need to store it in the page cache and then push it to the server + * to be sure the next read will get a valid data. */ - bool cache_ex = cinode->clientCanCacheAll; - bool cache_read = cinode->clientCanCacheRead; - int rc; - loff_t saved_pos; + if (!cinode->clientCanCacheAll && cinode->clientCanCacheRead) { + ssize_t written; + int rc; + + written = generic_file_aio_write(iocb, iov, nr_segs, pos); + rc = filemap_fdatawrite(inode->i_mapping); + if (rc) + return (ssize_t)rc; - if (cache_ex) { - if (cap_unix(tcon->ses) && - ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) && - (CIFS_UNIX_FCNTL_CAP & le64_to_cpu( - tcon->fsUnixInfo.Capability))) - return generic_file_aio_write(iocb, iov, nr_segs, pos); - return cifs_pagecache_writev(iocb, iov, nr_segs, pos, cache_ex); + return written; } +#endif /* - * For files without exclusive oplock in strict cache mode we need to - * write the data to the server exactly from the pos to pos+len-1 rather - * than flush all affected pages because it may cause a error with - * mandatory locks on these pages but not on the region from pos to - * ppos+len-1. + * For non-oplocked files in strict cache mode we need to write the data + * to the server exactly from the pos to pos+len-1 rather than flush all + * affected pages because it may cause a error with mandatory locks on + * these pages but not on the region from pos to ppos+len-1. */ - written = cifs_user_writev(iocb, iov, nr_segs, pos); - if (!cache_read || written <= 0) - return written; - saved_pos = iocb->ki_pos; - iocb->ki_pos = pos; - /* we have a read oplock - need to store a data in the page cache */ + if (!cinode->clientCanCacheAll) + return cifs_user_writev(iocb, iov, nr_segs, pos); + if (cap_unix(tcon->ses) && - ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) && - (CIFS_UNIX_FCNTL_CAP & le64_to_cpu( - tcon->fsUnixInfo.Capability))) - written2 = generic_file_aio_write(iocb, iov, nr_segs, pos); - else - written2 = cifs_pagecache_writev(iocb, iov, nr_segs, pos, - cache_ex); - /* errors occured during writing - invalidate the page cache */ - if (written2 < 0) { - rc = cifs_invalidate_mapping(inode); - if (rc) - written = (ssize_t)rc; - else - iocb->ki_pos = saved_pos; - } - return written; + (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) && + ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0)) + return generic_file_aio_write(iocb, iov, nr_segs, pos); + + return cifs_writev(iocb, iov, nr_segs, pos); } static struct cifs_readdata *