From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaegeuk Kim Subject: [PATCH 2/2] f2fs: don't give partially written atomic data from process crash Date: Tue, 25 Jul 2017 18:29:21 -0700 Message-ID: <20170726012921.53002-2-jaegeuk@kernel.org> References: <20170726012921.53002-1-jaegeuk@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.89) (envelope-from ) id 1daB8k-0001Kc-UC for linux-f2fs-devel@lists.sourceforge.net; Wed, 26 Jul 2017 01:29:30 +0000 Received: from mail.kernel.org ([198.145.29.99]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1daB8j-00031q-Vl for linux-f2fs-devel@lists.sourceforge.net; Wed, 26 Jul 2017 01:29:30 +0000 In-Reply-To: <20170726012921.53002-1-jaegeuk@kernel.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Jaegeuk Kim This patch resolves the below scenario. == Process 1 == == Process 2 == open(w) open(rw) begin write(new_#1) process_crash f_op->flush locks_remove_posix f_op>release read (new_#1) In order to avoid corrupted database caused by new_#1, we must do roll-back at process_crash time. In order to check that, this patch keeps task which triggers transaction begin, and does roll-back in f_op->flush before removing file locks. Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 1 + fs/f2fs/file.c | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index a336021b777f..3e48c2ac2f21 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -565,6 +565,7 @@ struct f2fs_inode_info { struct list_head dirty_list; /* dirty list for dirs and files */ struct list_head gdirty_list; /* linked in global dirty list */ struct list_head inmem_pages; /* inmemory pages managed by f2fs */ + struct task_struct *inmem_task; /* store inmemory task */ struct mutex inmem_lock; /* lock for inmemory pages */ struct extent_tree *extent_tree; /* cached extent_tree entry */ struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */ diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 0f4dbeb61845..cb0a013859e6 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1502,6 +1502,22 @@ static int f2fs_release_file(struct inode *inode, struct file *filp) return 0; } +static int f2fs_file_flush(struct file *file, fl_owner_t id) +{ + struct inode *inode = file_inode(file); + + /* + * If the process doing a transaction is crashed, we should do + * roll-back. Otherwise, other reader/write can see corrupted database + * until all the writers close its file. Since this should be done + * before dropping file lock, it needs to do in ->flush. + */ + if (f2fs_is_atomic_file(inode) && + F2FS_I(inode)->inmem_task == current) + drop_inmem_pages(inode); + return 0; +} + static int f2fs_ioc_getflags(struct file *filp, unsigned long arg) { struct inode *inode = file_inode(filp); @@ -1608,6 +1624,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp) } inc_stat: + F2FS_I(inode)->inmem_task = current; stat_inc_atomic_write(inode); stat_update_max_atomic_write(inode); out: @@ -2514,6 +2531,7 @@ const struct file_operations f2fs_file_operations = { .open = f2fs_file_open, .release = f2fs_release_file, .mmap = f2fs_file_mmap, + .flush = f2fs_file_flush, .fsync = f2fs_sync_file, .fallocate = f2fs_fallocate, .unlocked_ioctl = f2fs_ioctl, -- 2.13.0.rc1.294.g07d810a77f-goog ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot