From patchwork Wed Nov 21 02:44:00 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eiichi Tsukata X-Patchwork-Id: 1000849 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=etsukata.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=etsukata-com.20150623.gappssmtp.com header.i=@etsukata-com.20150623.gappssmtp.com header.b="L6mImjkx"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4306Nl52dQz9s7T for ; Wed, 21 Nov 2018 13:44:39 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726316AbeKUNQ5 (ORCPT ); Wed, 21 Nov 2018 08:16:57 -0500 Received: from mail-pl1-f196.google.com ([209.85.214.196]:35227 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726398AbeKUNQ5 (ORCPT ); Wed, 21 Nov 2018 08:16:57 -0500 Received: by mail-pl1-f196.google.com with SMTP id v1-v6so3208954plo.2 for ; Tue, 20 Nov 2018 18:44:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=etsukata-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=roGZa/MKql6l9BK2xvgfzkfB6UbYkloVfkrOARQfiPM=; b=L6mImjkxHwhkz5MgjbWQs1Bdl5HixsFOnS+PVuyYdbb//OsZhhZL3QReo/ycJEvUXf 52is2GuKGOF4FkREwDqE4dLAEaf66a5SgW3MVhue7Gz0B+oPs9REvOFLjsDwT8q8xeB4 h8koNaszwHNTBxst9A9uMusjxsS6Emb+qVfUzut83SW3eAWCF+fwMvVEd9Sm/Yikw+9o 61tnzlt+5LxImfOeqsUGw8476I/uY+B1uoIvY6N7pduX92/zlRR4k5PiBWLph7kBQWp8 UuGm+OSk9AOw165scmoA6lELO1w9oqPnDQQhdDm63WH2cTJPptto9Sv5VcpdoBf9nU9O k8PQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=roGZa/MKql6l9BK2xvgfzkfB6UbYkloVfkrOARQfiPM=; b=njqiZTdttIzqX3SRIDprf4MR+fmvBPNpAd6fdyh7JghzRa47Ptxe7L4/wQVoMSUsdR t3U5v8MWpgsvUxQWzTRJBEZlnvtJC/8fDgxvkWCoZynSuvw8ctPlWfaHtgCrAKqx+h3w 0wpMUUd0+0Tb9adh6CMCuUfGEkDTWRdofJTV9oyjopZeSz5j3ffsspOlv9748yM/kUIR leoCwfaQnYJKPgbI8DaV+k9+isBPetc0QqyjTSmPCD/eCAE8jjC5UMfEufPdFyxbAgHP K8gfEnWwGRDfGXrYwWi243aXzcXcpJ4X9vDpAk0+4AmNVsfHVoep+XMRKqATJCZSJGZx moOA== X-Gm-Message-State: AGRZ1gJ4x64085VsGU0I9h/f8Q+6lpFFGCdYuf1YTLbHUtNvf1Zn5TSF Z1lFYzIfcnr6WGA8QYcILLh6yg== X-Google-Smtp-Source: AJdET5c3PaB5bn7Jr0K2IjCIQuZpxqik+trbni3tBVgegGEJxUc4B/4QOTzlnS97VODoqDX5Y+Tb5w== X-Received: by 2002:a62:2ad6:: with SMTP id q205-v6mr4857372pfq.152.1542768275274; Tue, 20 Nov 2018 18:44:35 -0800 (PST) Received: from fedora.fout.local (fs76eecbcd.tkyc008.ap.nuro.jp. [118.238.203.205]) by smtp.gmail.com with ESMTPSA id l63-v6sm46356677pfb.75.2018.11.20.18.44.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 20 Nov 2018 18:44:34 -0800 (PST) From: Eiichi Tsukata To: andi@firstfloor.org, Chris Mason , Josef Bacik , David Sterba , "Theodore Ts'o" , Andreas Dilger , Jaegeuk Kim , Chao Yu , Miklos Szeredi , Bob Peterson , Andreas Gruenbacher , Alexander Viro , linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, cluster-devel@redhat.com, linux-unionfs@vger.kernel.org Cc: Eiichi Tsukata Subject: [PATCH v1 4/4] overlayfs: fix race between llseek SEEK_END and write Date: Wed, 21 Nov 2018 11:44:00 +0900 Message-Id: <20181121024400.4346-5-devel@etsukata.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181121024400.4346-1-devel@etsukata.com> References: <20181121024400.4346-1-devel@etsukata.com> MIME-Version: 1.0 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Implement individual lock for SEEK_END for overlayfs which directly calls generic_file_llseek_size(). Signed-off-by: Eiichi Tsukata --- fs/overlayfs/file.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 84dd957efa24..57bc6538eea8 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -146,10 +146,27 @@ static int ovl_release(struct inode *inode, struct file *file) static loff_t ovl_llseek(struct file *file, loff_t offset, int whence) { struct inode *realinode = ovl_inode_real(file_inode(file)); + loff_t ret; - return generic_file_llseek_size(file, offset, whence, - realinode->i_sb->s_maxbytes, - i_size_read(realinode)); + switch (whence) { + default: + return generic_file_llseek_size(file, offset, whence, + realinode->i_sb->s_maxbytes, + i_size_read(realinode)); + case SEEK_END: + case SEEK_DATA: + case SEEK_HOLE: + /* + * protects against inode size race with write so that llseek + * doesn't see inode size being updated in individual fs write + */ + inode_lock(realinode); + ret = generic_file_llseek_size(file, offset, whence, + realinode->i_sb->s_maxbytes, + i_size_read(realinode)); + inode_unlock(realinode); + return ret; + } } static void ovl_file_accessed(struct file *file)