From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D9AF19FA86 for ; Mon, 24 Jun 2024 17:53:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719251607; cv=none; b=YN/VAgpMVCdQWKj+9yCyF0JLokRLyzVb89YIS81gxYEz5038YlqR+ivCJZLoC2YMBjZtoKtAZXudzH4gn4iigWkOgz+FPf07FfqOJhrqMmpjv5r3HZbT7fkcAVQxadrRj/YVKQnhk6seWpjOP3xYeZIUSFgh7152StQPEPj3Bmg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719251607; c=relaxed/simple; bh=sV7eppB4xqZxl7orWq5DEhrQtYxq9XdZxd/7zbygi5Y=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pZn1/V7hCgs7k5stzekkUqC0HJRJy1N0zzZLC6ejxtY1R/kkGBi1sKf1SWiQFRUy1Gsc4gpoPjFBwvAS+OClkoYqvTZuTOTqojDu5gjtmjieNElMGdbLonwtPIU1CX80cOL9LWZ2xKzRXitOA8ly5iDutpOWAaVHEka7wAXFDRQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=emrSZSLO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="emrSZSLO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C41ADC32789; Mon, 24 Jun 2024 17:53:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719251607; bh=sV7eppB4xqZxl7orWq5DEhrQtYxq9XdZxd/7zbygi5Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=emrSZSLO81R0j6/M/RlR4nDU5/cXe/8EtimLnx4K76ipJHenhNkolVfyNvHthEJw8 PIPWOvrZOPigrlWsyjSEWsvgNZjERHYPodUeom2ibbJCHBBn//pjt+fWq8ov1KF5OE 0BcQt2WEYpQICQU8QMaain3NtTb7mfmUWOECXtjKvF2HKiPGmUd283CW/8M+/Q1Qk2 prvZ8U88rPTjY8220bzZZkqgEqtBZdbUpwFTxw8rrIV5TBaTzaZedfETcLRoODwZlT mFeWQqvRoC20pkbCFb6VC8L2AFrHxRWUtkT58oXkUFhYLT2q0cA+PblXkglIkk69uR lF0nx0KaNr8Ow== Date: Mon, 24 Jun 2024 17:53:25 +0000 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Yunlei He Subject: Re: [PATCH] f2fs: fix to update user block counts in block_operations() Message-ID: References: <20240606095451.4088735-1-chao@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240606095451.4088735-1-chao@kernel.org> On 06/06, Chao Yu wrote: > Commit 59c9081bc86e ("f2fs: allow write page cache when writting cp") > allows write() to write data to page cache during checkpoint, so block > count fields like .total_valid_block_count, .alloc_valid_block_count > and .rf_node_block_count may encounter race condition as below: > > CP Thread A > - write_checkpoint > - block_operations > - f2fs_down_write(&sbi->node_change) > - __prepare_cp_block > : ckpt->valid_block_count = .total_valid_block_count > - f2fs_up_write(&sbi->node_change) > - write > - f2fs_preallocate_blocks > - f2fs_map_blocks(,F2FS_GET_BLOCK_PRE_AIO) > - f2fs_map_lock > - f2fs_down_read(&sbi->node_change) > - f2fs_reserve_new_blocks > - inc_valid_block_count > : percpu_counter_add(&sbi->alloc_valid_block_count, count) > : sbi->total_valid_block_count += count > - f2fs_up_read(&sbi->node_change) > - do_checkpoint > : sbi->last_valid_block_count = sbi->total_valid_block_count > : percpu_counter_set(&sbi->alloc_valid_block_count, 0) > : percpu_counter_set(&sbi->rf_node_block_count, 0) > - fsync > - need_do_checkpoint > - f2fs_space_for_roll_forward > : alloc_valid_block_count was reset to zero, > so, it may missed last data during checkpoint > > Let's change to update .total_valid_block_count, .alloc_valid_block_count > and .rf_node_block_count in block_operations(), then their access can be > protected by .node_change and .cp_rwsem lock, so that it can avoid above > race condition. > > Fixes: 59c9081bc86e ("f2fs: allow write page cache when writting cp") > Cc: Yunlei He > Signed-off-by: Chao Yu > --- > fs/f2fs/checkpoint.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > index 66eaad591b60..010bbd5af211 100644 > --- a/fs/f2fs/checkpoint.c > +++ b/fs/f2fs/checkpoint.c > @@ -1298,6 +1298,12 @@ static int block_operations(struct f2fs_sb_info *sbi) > * dirty node blocks and some checkpoint values by block allocation. > */ > __prepare_cp_block(sbi); > + > + /* update user_block_counts */ > + sbi->last_valid_block_count = sbi->total_valid_block_count; > + percpu_counter_set(&sbi->alloc_valid_block_count, 0); > + percpu_counter_set(&sbi->rf_node_block_count, 0); Need to add this in __prepare_cp_block()? > + > f2fs_up_write(&sbi->node_change); > return err; > } > @@ -1575,11 +1581,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) > start_blk += NR_CURSEG_NODE_TYPE; > } > > - /* update user_block_counts */ > - sbi->last_valid_block_count = sbi->total_valid_block_count; > - percpu_counter_set(&sbi->alloc_valid_block_count, 0); > - percpu_counter_set(&sbi->rf_node_block_count, 0); > - > /* Here, we have one bio having CP pack except cp pack 2 page */ > f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO); > /* Wait for all dirty meta pages to be submitted for IO */ > -- > 2.40.1 >