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=-16.2 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 C630DC433DB for ; Mon, 11 Jan 2021 16:33:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C4A7221FE for ; Mon, 11 Jan 2021 16:33:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388962AbhAKQdC (ORCPT ); Mon, 11 Jan 2021 11:33:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:40258 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387954AbhAKQdA (ORCPT ); Mon, 11 Jan 2021 11:33:00 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 086C42076D; Mon, 11 Jan 2021 16:32:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610382739; bh=n58+kriku0xNNNV/3xenUPJRY7XCq3l2G6iv1P43ze8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oi/8BOafwrkXdaFQDbehDZVYAvYx6tJuWdCFwbI0tJ6BKpXJ82YM1qSEyNC4fZ/gJ UjefflHFfY9GB0UKcpZrBZVhusE8O/IBTNP4gsOzfEZwUI7cXi0QTnUovfecmGAQTm YjUvTicIysprKflCftPRvnMlyJ7jwuTs1seV8rXMP3+4Gs6DafjS3OOtSaWgjXIGC+ 7Jv5Jo9ZUk9v5r46MqIkqUibLGGHNJNVx+tDnX9jKwgPoyAdT8cvoaIr+/aFUWApfN sY6ZbEkewOvWw7SiQUXcM3+da4PdeHZh68lV9gX+ANo4CV/4WGcQKHllcF6e00j3yw dwqtnPvUS63Zw== Date: Mon, 11 Jan 2021 08:32:17 -0800 From: Jaegeuk Kim To: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/06, Jaegeuk Kim wrote: > On 01/06, Jaegeuk Kim wrote: > > 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 > > nvm. I can see it works now. Hmm, this gives a huge perf regression when running sqlite. :( We may need to check the lock coverage. Thoughts? > > > > > 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 > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel 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 C906BC433E6 for ; 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bh=X7OQ42Qi5avNbSpaGLAGFb/07g7uvMTodZiUY53guaI=; b=CHdpofw+/fMXvnxPyGicGdGYZ8 XpbNE0qyAPYJwwmSrATa0HoGK1n5BIt27uBcPn+TM4RgMxqEgVpQnKszq604581ANss8ozhpJ8Cpw yRZBZkzbZ5flEt4Y0FKFpBAmEozUZ/zJ22AEppbeXNnymrQxOpTA9uvbA6eLFZOAef2o=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-1.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.2) id 1kz07J-009ri8-JR for linux-f2fs-devel@lists.sourceforge.net; Mon, 11 Jan 2021 16:32:38 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 086C42076D; Mon, 11 Jan 2021 16:32:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610382739; bh=n58+kriku0xNNNV/3xenUPJRY7XCq3l2G6iv1P43ze8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oi/8BOafwrkXdaFQDbehDZVYAvYx6tJuWdCFwbI0tJ6BKpXJ82YM1qSEyNC4fZ/gJ UjefflHFfY9GB0UKcpZrBZVhusE8O/IBTNP4gsOzfEZwUI7cXi0QTnUovfecmGAQTm YjUvTicIysprKflCftPRvnMlyJ7jwuTs1seV8rXMP3+4Gs6DafjS3OOtSaWgjXIGC+ 7Jv5Jo9ZUk9v5r46MqIkqUibLGGHNJNVx+tDnX9jKwgPoyAdT8cvoaIr+/aFUWApfN sY6ZbEkewOvWw7SiQUXcM3+da4PdeHZh68lV9gX+ANo4CV/4WGcQKHllcF6e00j3yw dwqtnPvUS63Zw== Date: Mon, 11 Jan 2021 08:32:17 -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: X-Headers-End: 1kz07J-009ri8-JR 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 On 01/06, Jaegeuk Kim wrote: > On 01/06, Jaegeuk Kim wrote: > > 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 > > nvm. I can see it works now. Hmm, this gives a huge perf regression when running sqlite. :( We may need to check the lock coverage. Thoughts? > > > > > 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 > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel