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 Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2729AC04FFE for ; Tue, 14 May 2024 16:09:55 +0000 (UTC) Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1s6uiu-0007kI-Ug; Tue, 14 May 2024 16:09:54 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1s6uit-0007kB-3N for linux-f2fs-devel@lists.sourceforge.net; Tue, 14 May 2024 16:09:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=In-Reply-To:Content-Type:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=1DlV4gPAgtl1d1efkdLJhhZQM5HqjuD8ObpZJZ9prVc=; b=crewTfLtJsqPQjVdLPveTEDsso OuYbwjHzmVEmG4fSLU/x3ToVPxGe9SGiYyOWqYH+mqQQh7kZt2bdP/LnyBmpF6vH40U1I0zVDOrew WUBBipX0zL77McIBNaNlfQvyU9Bzzx7ia8gq0nTdppxEU3mrFxfbmxTBw0A4PQDd+eAE=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To :From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=1DlV4gPAgtl1d1efkdLJhhZQM5HqjuD8ObpZJZ9prVc=; b=Aw/Azdwibvx3kh2ozA3pHqY0mx Oon4RZ800hs4hDhVVnX5L6gsII9hyU4mjNiH3lhaglDXnevsJlGrJ0L0NycS3y9CP5vmQsILPQQdL UQtDqwgZCjCPX2GIJQlqOSKpuFFNn9+YHyMwZ5jv6yZZ9mkhtMpFcVeJRemWuvFifOHk=; Received: from sin.source.kernel.org ([145.40.73.55]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1s6uit-0001CU-UK for linux-f2fs-devel@lists.sourceforge.net; Tue, 14 May 2024 16:09:52 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 3B3A2CE12BE for ; Tue, 14 May 2024 16:09:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3D778C2BD10; Tue, 14 May 2024 16:09:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715702978; bh=vhQydVTRtjxkPaHb5KfVHAR+hCQTbKZ2234Oroi1hkk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=f+/wsULAYEK1/fTo01gH+G2dGG4b99QqEId2LHiohLXde5DsJCjgTWg/AWDm66LfM EaCqJK35ynrCMgWiTpia/h1/YK0KGoGRRJgR2OmX/t2VOr6wleU9WSFt2kc8PCbvpZ 4RJyETwgviu8wbqQ2KJzUjsMUTr7fYvM37QVJ6/WI1YfBhU8QuzHeLFMvpCSsJFIKa xwCIEy/2W2/BDleGrj1+E65oHoUV15Tovptz9a/UkfegFFqPfTVdFB5+xK1jgj9JQ8 A4SgFBJ1lYT4nO28IeV3Xx/j7/66yzEHqZOyv861ONTGQ8o8B4uVPRsAYpiAQTSy+T dKUE0VN0ZRAVA== Date: Tue, 14 May 2024 16:09:36 +0000 From: Jaegeuk Kim To: Chao Yu Message-ID: References: <20240510023906.281700-1-chao@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240510023906.281700-1-chao@kernel.org> X-Headers-End: 1s6uit-0001CU-UK Subject: Re: [f2fs-dev] [PATCH v2] f2fs: fix to avoid racing in between read and OPU dio 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 05/10, Chao Yu wrote: > If lfs mode is on, buffered read may race w/ OPU dio write as below, > it may cause buffered read hits unwritten data unexpectly, and for > dio read, the race condition exists as well. > > Thread A Thread B > - f2fs_file_write_iter > - f2fs_dio_write_iter > - __iomap_dio_rw > - f2fs_iomap_begin > - f2fs_map_blocks > - __allocate_data_block > - allocated blkaddr #x > - iomap_dio_submit_bio > - f2fs_file_read_iter > - filemap_read > - f2fs_read_data_folio > - f2fs_mpage_readpages > - f2fs_map_blocks > : get blkaddr #x > - f2fs_submit_read_bio > IRQ > - f2fs_read_end_io > : read IO on blkaddr #x complete > IRQ > - iomap_dio_bio_end_io > : direct write IO on blkaddr #x complete > > This patch introduces a new per-inode i_opu_rwsem lock to avoid > such race condition. Wasn't this supposed to be managed by user-land? > > Fixes: f847c699cff3 ("f2fs: allow out-place-update for direct IO in LFS mode") > Signed-off-by: Chao Yu > --- > v2: > - fix to cover dio read path w/ i_opu_rwsem as well. > fs/f2fs/f2fs.h | 1 + > fs/f2fs/file.c | 28 ++++++++++++++++++++++++++-- > fs/f2fs/super.c | 1 + > 3 files changed, 28 insertions(+), 2 deletions(-) > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 30058e16a5d0..91cf4b3d6bc6 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -847,6 +847,7 @@ struct f2fs_inode_info { > /* avoid racing between foreground op and gc */ > struct f2fs_rwsem i_gc_rwsem[2]; > struct f2fs_rwsem i_xattr_sem; /* avoid racing between reading and changing EAs */ > + struct f2fs_rwsem i_opu_rwsem; /* avoid racing between buf read and opu dio write */ > > int i_extra_isize; /* size of extra space located in i_addr */ > kprojid_t i_projid; /* id for project quota */ > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index 72ce1a522fb2..4ec260af321f 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -4445,6 +4445,7 @@ static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) > const loff_t pos = iocb->ki_pos; > const size_t count = iov_iter_count(to); > struct iomap_dio *dio; > + bool do_opu = f2fs_lfs_mode(sbi); > ssize_t ret; > > if (count == 0) > @@ -4457,8 +4458,14 @@ static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) > ret = -EAGAIN; > goto out; > } > + if (do_opu && !f2fs_down_read_trylock(&fi->i_opu_rwsem)) { > + f2fs_up_read(&fi->i_gc_rwsem[READ]); > + ret = -EAGAIN; > + goto out; > + } > } else { > f2fs_down_read(&fi->i_gc_rwsem[READ]); > + f2fs_down_read(&fi->i_opu_rwsem); > } > > /* > @@ -4477,6 +4484,7 @@ static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) > ret = iomap_dio_complete(dio); > } > > + f2fs_up_read(&fi->i_opu_rwsem); > f2fs_up_read(&fi->i_gc_rwsem[READ]); > > file_accessed(file); > @@ -4523,7 +4531,13 @@ static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) > if (f2fs_should_use_dio(inode, iocb, to)) { > ret = f2fs_dio_read_iter(iocb, to); > } else { > + bool do_opu = f2fs_lfs_mode(F2FS_I_SB(inode)); > + > + if (do_opu) > + f2fs_down_read(&F2FS_I(inode)->i_opu_rwsem); > ret = filemap_read(iocb, to, 0); > + if (do_opu) > + f2fs_up_read(&F2FS_I(inode)->i_opu_rwsem); > if (ret > 0) > f2fs_update_iostat(F2FS_I_SB(inode), inode, > APP_BUFFERED_READ_IO, ret); > @@ -4748,14 +4762,22 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from, > ret = -EAGAIN; > goto out; > } > + if (do_opu && !f2fs_down_write_trylock(&fi->i_opu_rwsem)) { > + f2fs_up_read(&fi->i_gc_rwsem[READ]); > + f2fs_up_read(&fi->i_gc_rwsem[WRITE]); > + ret = -EAGAIN; > + goto out; > + } > } else { > ret = f2fs_convert_inline_inode(inode); > if (ret) > goto out; > > f2fs_down_read(&fi->i_gc_rwsem[WRITE]); > - if (do_opu) > + if (do_opu) { > f2fs_down_read(&fi->i_gc_rwsem[READ]); > + f2fs_down_write(&fi->i_opu_rwsem); > + } > } > > /* > @@ -4779,8 +4801,10 @@ static ssize_t f2fs_dio_write_iter(struct kiocb *iocb, struct iov_iter *from, > ret = iomap_dio_complete(dio); > } > > - if (do_opu) > + if (do_opu) { > + f2fs_up_write(&fi->i_opu_rwsem); > f2fs_up_read(&fi->i_gc_rwsem[READ]); > + } > f2fs_up_read(&fi->i_gc_rwsem[WRITE]); > > if (ret < 0) > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index daf2c4dbe150..b4ed3b094366 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -1428,6 +1428,7 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb) > init_f2fs_rwsem(&fi->i_gc_rwsem[READ]); > init_f2fs_rwsem(&fi->i_gc_rwsem[WRITE]); > init_f2fs_rwsem(&fi->i_xattr_sem); > + init_f2fs_rwsem(&fi->i_opu_rwsem); > > /* Will be used by directory only */ > fi->i_dir_level = F2FS_SB(sb)->dir_level; > -- > 2.40.1 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel