From nobody Fri Oct 3 19:27:12 2025 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 4472317F4E7 for ; Thu, 6 Jun 2024 09:54:56 +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=1717667697; cv=none; b=PoASQ7GXomRJeNsMS8aIWbWP2qgY0joUUw3jwh8gKvc8t4rmfMKw7WfgVvbc1cJApS2rRBlpDYQhlOdJHxBYVO1l4kwq4gQi/RViEcDdfFJkFsEJQlTbVtUXn79M26bPq4SnihNCWjWoYrWuVYUPavBReyJGDEQaJbsK8dade7s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717667697; c=relaxed/simple; bh=GNpmoUqNJ5Xzdvywh8sIQ3KCs7bJubcVgL87Sik46R0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=f4Lczg4aHJ/kBtovvNC8b7fXWzmJ7iNGtr9dhu8jDpUNvIURZMnmqOGl1mP2xNCii+NH5utMO0tsAr/cXEXMKdZwNFhZLMRHiU13vXV4m7fyoSS2fpVb3ohyZisV88wZhipAdIk5RI4ucy90MuSe9RpwURq6ftfFNwuOfzx3zpk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Sp+/mZ1D; 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="Sp+/mZ1D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54FA1C4AF0B; Thu, 6 Jun 2024 09:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717667696; bh=GNpmoUqNJ5Xzdvywh8sIQ3KCs7bJubcVgL87Sik46R0=; h=From:To:Cc:Subject:Date:From; b=Sp+/mZ1DDMC7/qtA4SInsKKdOF3SmxZP1uldo8Ec63DG2w07Fxk2pFOaQCbhk0KKm XWRCh+ws2PXyLc7b2rEF2PXtUGGlFVrT1WXM/dFbEWItPhOfQyduE/V/t0dafCl5kF Z4jgd3jn/jxADd5y+Mva+Mv3jKBjG9Y+tID+l2skQC88THT/eUX6rpU5KSjnGgHIse Od2kJXhMEOfLyfKlkaNzzpjwwJDTQR3ghPcaGO5jAhhFY4xgImxKaU4fcIemrDuXoA UW8UzbgBPM/QAOer/RjAMe4jzgoHtM+yS+CZpJiFA3BydGoYv4BHpPb60y4BD+Wxxy p1zMGEA7tSZbA== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu , Yunlei He Subject: [PATCH] f2fs: fix to update user block counts in block_operations() Date: Thu, 6 Jun 2024 17:54:51 +0800 Message-Id: <20240606095451.4088735-1-chao@kernel.org> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 =3D .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 +=3D count - f2fs_up_read(&sbi->node_change) - do_checkpoint : sbi->last_valid_block_count =3D 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 =3D sbi->total_valid_block_count; + percpu_counter_set(&sbi->alloc_valid_block_count, 0); + percpu_counter_set(&sbi->rf_node_block_count, 0); + f2fs_up_write(&sbi->node_change); return err; } @@ -1575,11 +1581,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, s= truct cp_control *cpc) start_blk +=3D NR_CURSEG_NODE_TYPE; } =20 - /* update user_block_counts */ - sbi->last_valid_block_count =3D 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 */ --=20 2.40.1