From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CEA7C433E0 for ; Wed, 6 Jan 2021 22:29:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C0F2206FA for ; Wed, 6 Jan 2021 22:29:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727308AbhAFW3f (ORCPT ); Wed, 6 Jan 2021 17:29:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:44012 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726379AbhAFW3e (ORCPT ); Wed, 6 Jan 2021 17:29:34 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2454422CE3; Wed, 6 Jan 2021 22:28:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1609972134; bh=9kO3TfbkRg07D293QME5ftnHAMoedTFfNXUSMyghj7w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZFlNqrlln71UIiLGiWzkFXkwRHZvgkyQckOyt5d3Bc/ST8DZTbFULoaeCe5GPGPX0 1+rKTNC9IAKJs3txMr7ce/sPL2z1MGIMs2NjNivQ7hEkwSBuW99nBvbtBfoBHePNmz yryb1HbvmKnC9x9/8GHewXCDetdfz9XttBVlNPGhFfZmBxapXvyWy2cmbSBp+PRl8L tMMnPDbMmedmLCqdIB+AXWgjLypLdA85nnyNwhOQ3eQZyGEWOiFCMUacfkD/yGlqW/ T/A9FeGWEYsKExK3vDMZYfwR+pYMrSkLW3aLQG++3VNma9ApN3r5cPb+DXCeyJKAMT U/xMW280P3c8w== Date: Wed, 6 Jan 2021 14:28:52 -0800 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, chao@kernel.org Subject: Re: [PATCH v2] f2fs: fix to keep isolation of atomic write Message-ID: References: <20201230075557.108818-1-yuchao0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201230075557.108818-1-yuchao0@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chao, With a quick test, this patch causes down_write failure resulting in blocking process. I didn't dig in the bug so, please check the code again. :P On 12/30, Chao Yu wrote: > ThreadA ThreadB > - f2fs_ioc_start_atomic_write > - write > - f2fs_ioc_commit_atomic_write > - f2fs_commit_inmem_pages > - f2fs_drop_inmem_pages > - f2fs_drop_inmem_pages > - __revoke_inmem_pages > - f2fs_vm_page_mkwrite > - set_page_dirty > - tag ATOMIC_WRITTEN_PAGE and add page > to inmem_pages list > - clear_inode_flag(FI_ATOMIC_FILE) > - f2fs_vm_page_mkwrite > - set_page_dirty > - f2fs_update_dirty_page > - f2fs_trace_pid > - tag inmem page private to pid > - truncate > - f2fs_invalidate_page > - set page->mapping to NULL > then it will cause panic once we > access page->mapping > > The root cause is we missed to keep isolation of atomic write in the case > of commit_atomic_write vs mkwrite, let commit_atomic_write helds i_mmap_sem > lock to avoid this issue. > > Signed-off-by: Chao Yu > --- > v2: > - use i_mmap_sem to avoid mkwrite racing with below flows: > * f2fs_ioc_start_atomic_write > * f2fs_drop_inmem_pages > * f2fs_commit_inmem_pages > > fs/f2fs/file.c | 3 +++ > fs/f2fs/segment.c | 7 +++++++ > 2 files changed, 10 insertions(+) > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index 4e6d4b9120a8..a48ec650d691 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > goto out; > > down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > + down_write(&F2FS_I(inode)->i_mmap_sem); > > /* > * Should wait end_io to count F2FS_WB_CP_DATA correctly by > @@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > inode->i_ino, get_dirty_pages(inode)); > ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX); > if (ret) { > + up_write(&F2FS_I(inode)->i_mmap_sem); > up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > goto out; > } > @@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > /* add inode in inmem_list first and set atomic_file */ > set_inode_flag(inode, FI_ATOMIC_FILE); > clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); > + up_write(&F2FS_I(inode)->i_mmap_sem); > up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > > f2fs_update_time(F2FS_I_SB(inode), REQ_TIME); > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index d8570b0359f5..dab870d9faf6 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode) > struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > struct f2fs_inode_info *fi = F2FS_I(inode); > > + down_write(&F2FS_I(inode)->i_mmap_sem); > + > while (!list_empty(&fi->inmem_pages)) { > mutex_lock(&fi->inmem_lock); > __revoke_inmem_pages(inode, &fi->inmem_pages, > @@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode) > sbi->atomic_files--; > } > spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); > + > + up_write(&F2FS_I(inode)->i_mmap_sem); > } > > void f2fs_drop_inmem_page(struct inode *inode, struct page *page) > @@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode) > f2fs_balance_fs(sbi, true); > > down_write(&fi->i_gc_rwsem[WRITE]); > + down_write(&F2FS_I(inode)->i_mmap_sem); > > f2fs_lock_op(sbi); > set_inode_flag(inode, FI_ATOMIC_COMMIT); > @@ -478,6 +483,8 @@ int f2fs_commit_inmem_pages(struct inode *inode) > clear_inode_flag(inode, FI_ATOMIC_COMMIT); > > f2fs_unlock_op(sbi); > + > + up_write(&F2FS_I(inode)->i_mmap_sem); > up_write(&fi->i_gc_rwsem[WRITE]); > > return err; > -- > 2.29.2 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 260BEC433DB for ; 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bh=k4rzpbRr+cFtjidNRa/A5a5O2+mJHCyOGcyWVKMRqbQ=; b=RqKOyGPwgE1L9Ep5AP2pyQ5AA8 dnTd8M+fiCQpt6t+kTqAw+vGdCNfGGkB02ORvyheTblG0mFJvd9Yb2CktY6NtFCyWN7jRwtohEjMc 5kVsoXmmMW9jexozfauEHelBhHEKvTrp86nTAufJTHYeJJ0NiDa9wQyxPSNrOFClcN9k=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-3.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.2) id 1kxHIg-0004dR-OG for linux-f2fs-devel@lists.sourceforge.net; Wed, 06 Jan 2021 22:29:15 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2454422CE3; Wed, 6 Jan 2021 22:28:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1609972134; bh=9kO3TfbkRg07D293QME5ftnHAMoedTFfNXUSMyghj7w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZFlNqrlln71UIiLGiWzkFXkwRHZvgkyQckOyt5d3Bc/ST8DZTbFULoaeCe5GPGPX0 1+rKTNC9IAKJs3txMr7ce/sPL2z1MGIMs2NjNivQ7hEkwSBuW99nBvbtBfoBHePNmz yryb1HbvmKnC9x9/8GHewXCDetdfz9XttBVlNPGhFfZmBxapXvyWy2cmbSBp+PRl8L tMMnPDbMmedmLCqdIB+AXWgjLypLdA85nnyNwhOQ3eQZyGEWOiFCMUacfkD/yGlqW/ T/A9FeGWEYsKExK3vDMZYfwR+pYMrSkLW3aLQG++3VNma9ApN3r5cPb+DXCeyJKAMT U/xMW280P3c8w== Date: Wed, 6 Jan 2021 14:28:52 -0800 From: Jaegeuk Kim To: Chao Yu Message-ID: References: <20201230075557.108818-1-yuchao0@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201230075557.108818-1-yuchao0@huawei.com> X-Headers-End: 1kxHIg-0004dR-OG Subject: Re: [f2fs-dev] [PATCH v2] f2fs: fix to keep isolation of atomic write X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net Hi Chao, With a quick test, this patch causes down_write failure resulting in blocking process. I didn't dig in the bug so, please check the code again. :P On 12/30, Chao Yu wrote: > ThreadA ThreadB > - f2fs_ioc_start_atomic_write > - write > - f2fs_ioc_commit_atomic_write > - f2fs_commit_inmem_pages > - f2fs_drop_inmem_pages > - f2fs_drop_inmem_pages > - __revoke_inmem_pages > - f2fs_vm_page_mkwrite > - set_page_dirty > - tag ATOMIC_WRITTEN_PAGE and add page > to inmem_pages list > - clear_inode_flag(FI_ATOMIC_FILE) > - f2fs_vm_page_mkwrite > - set_page_dirty > - f2fs_update_dirty_page > - f2fs_trace_pid > - tag inmem page private to pid > - truncate > - f2fs_invalidate_page > - set page->mapping to NULL > then it will cause panic once we > access page->mapping > > The root cause is we missed to keep isolation of atomic write in the case > of commit_atomic_write vs mkwrite, let commit_atomic_write helds i_mmap_sem > lock to avoid this issue. > > Signed-off-by: Chao Yu > --- > v2: > - use i_mmap_sem to avoid mkwrite racing with below flows: > * f2fs_ioc_start_atomic_write > * f2fs_drop_inmem_pages > * f2fs_commit_inmem_pages > > fs/f2fs/file.c | 3 +++ > fs/f2fs/segment.c | 7 +++++++ > 2 files changed, 10 insertions(+) > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index 4e6d4b9120a8..a48ec650d691 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -2050,6 +2050,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > goto out; > > down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > + down_write(&F2FS_I(inode)->i_mmap_sem); > > /* > * Should wait end_io to count F2FS_WB_CP_DATA correctly by > @@ -2060,6 +2061,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > inode->i_ino, get_dirty_pages(inode)); > ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX); > if (ret) { > + up_write(&F2FS_I(inode)->i_mmap_sem); > up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > goto out; > } > @@ -2073,6 +2075,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) > /* add inode in inmem_list first and set atomic_file */ > set_inode_flag(inode, FI_ATOMIC_FILE); > clear_inode_flag(inode, FI_ATOMIC_REVOKE_REQUEST); > + up_write(&F2FS_I(inode)->i_mmap_sem); > up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); > > f2fs_update_time(F2FS_I_SB(inode), REQ_TIME); > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index d8570b0359f5..dab870d9faf6 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -327,6 +327,8 @@ void f2fs_drop_inmem_pages(struct inode *inode) > struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > struct f2fs_inode_info *fi = F2FS_I(inode); > > + down_write(&F2FS_I(inode)->i_mmap_sem); > + > while (!list_empty(&fi->inmem_pages)) { > mutex_lock(&fi->inmem_lock); > __revoke_inmem_pages(inode, &fi->inmem_pages, > @@ -344,6 +346,8 @@ void f2fs_drop_inmem_pages(struct inode *inode) > sbi->atomic_files--; > } > spin_unlock(&sbi->inode_lock[ATOMIC_FILE]); > + > + up_write(&F2FS_I(inode)->i_mmap_sem); > } > > void f2fs_drop_inmem_page(struct inode *inode, struct page *page) > @@ -467,6 +471,7 @@ int f2fs_commit_inmem_pages(struct inode *inode) > f2fs_balance_fs(sbi, true); > > down_write(&fi->i_gc_rwsem[WRITE]); > + down_write(&F2FS_I(inode)->i_mmap_sem); > > f2fs_lock_op(sbi); > set_inode_flag(inode, FI_ATOMIC_COMMIT); > @@ -478,6 +483,8 @@ int f2fs_commit_inmem_pages(struct inode *inode) > clear_inode_flag(inode, FI_ATOMIC_COMMIT); > > f2fs_unlock_op(sbi); > + > + up_write(&F2FS_I(inode)->i_mmap_sem); > up_write(&fi->i_gc_rwsem[WRITE]); > > return err; > -- > 2.29.2 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel