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 0F0981D150F; Wed, 2 Oct 2024 14:42:53 +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=1727880173; cv=none; b=UCUym5ZmZreDLuhzNmMpTGTz/SP63gygrivcBflEfldvZNT53I6mNiucXRdaOEMshkAKEfc+KSSR1pgB7JGZTkX/rPwupItz0yrMJwJgvomkeXgJE/aOwPiabX+SYJmVZ3sPkRYNcSDEkXfiZIDLgcsZnSqrMA2G5+PsvKjioCQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727880173; c=relaxed/simple; bh=esRzHWybCOLC7XG2XQJj9x0RuGxN/PHG5xmYQYC9AZU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tXwjhT1m5gkFEdWowD/zR+YaG2c4NYaZq/dIrvU05PWu1J3LJ4wF4mZYyoKQTfHhH9yfKVcOM0472LbWwk2hJpj2mctP8V6WCv28HRVS164m/KLHrUmcZMnl9cToGbEZGQWYrbVGaZVh/ixmaAi3WDjbeylLcDMQSRTbJsJZS70= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ssiRf3j4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ssiRf3j4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B15BC4CEC2; Wed, 2 Oct 2024 14:42:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727880172; bh=esRzHWybCOLC7XG2XQJj9x0RuGxN/PHG5xmYQYC9AZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ssiRf3j4fOfg3wSwZ8J8YQGWXjEywN5LoCvk1GzHkhb4y9KBJAt11G77IGEJCBS3N xZ7W3MTVzi2ARlX/h7LEol7Ltwji7q9JFqxhW0jXmpsIX010N9SHkjjgP2lZ3noZCe 8Hd3q9DoHDs7zbN0TcYcJrq6JTLIkVdWNzKBSOQI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.6 336/538] f2fs: fix to avoid racing in between read and OPU dio write Date: Wed, 2 Oct 2024 14:59:35 +0200 Message-ID: <20241002125805.694809051@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125751.964700919@linuxfoundation.org> References: <20241002125751.964700919@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chao Yu [ Upstream commit 0cac51185e65dc2a20686184e02f3cafc99eb202 ] 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 In LFS mode, if there is inflight dio, let's wait for its completion, this policy won't cover all race cases, however it is a tradeoff which avoids abusing lock around IO paths. Fixes: f847c699cff3 ("f2fs: allow out-place-update for direct IO in LFS mode") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin --- fs/f2fs/file.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 81e342bd993c2..8c4c5c6c1ac64 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -4541,6 +4541,10 @@ static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) f2fs_trace_rw_file_path(iocb->ki_filp, iocb->ki_pos, iov_iter_count(to), READ); + /* In LFS mode, if there is inflight dio, wait for its completion */ + if (f2fs_lfs_mode(F2FS_I_SB(inode))) + inode_dio_wait(inode); + if (f2fs_should_use_dio(inode, iocb, to)) { ret = f2fs_dio_read_iter(iocb, to); } else { -- 2.43.0