From patchwork Tue Oct 19 12:39:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "yebin (H)" X-Patchwork-Id: 1543275 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee2:21ea]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4HYY076Lqnz9sR4 for ; Tue, 19 Oct 2021 23:27:03 +1100 (AEDT) Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4HYY075gwLz4xbb for ; Tue, 19 Oct 2021 23:27:03 +1100 (AEDT) Received: by gandalf.ozlabs.org (Postfix) id 4HYY075fFyz4xd9; Tue, 19 Oct 2021 23:27:03 +1100 (AEDT) Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: gandalf.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4HYY075btHz4xbb for ; Tue, 19 Oct 2021 23:27:03 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235602AbhJSM3P (ORCPT ); Tue, 19 Oct 2021 08:29:15 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:24359 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231441AbhJSM3M (ORCPT ); Tue, 19 Oct 2021 08:29:12 -0400 Received: from dggeme754-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4HYXtn3rXdzbhCr; Tue, 19 Oct 2021 20:22:25 +0800 (CST) Received: from huawei.com (10.175.127.227) by dggeme754-chm.china.huawei.com (10.3.19.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.15; Tue, 19 Oct 2021 20:26:58 +0800 From: Ye Bin To: , , CC: , , Ye Bin Subject: [PATCH -next v4 3/3] ext4: simplify read_mmp_block fucntion Date: Tue, 19 Oct 2021 20:39:31 +0800 Message-ID: <20211019123931.1545295-4-yebin10@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211019123931.1545295-1-yebin10@huawei.com> References: <20211019123931.1545295-1-yebin10@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggeme754-chm.china.huawei.com (10.3.19.100) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org This patch is according to Jan Kara's suggestion: I guess I would just get rid of sb_getblk() in read_mmp_block() and always expect valid bh passed. The only place that passes NULL bh after this patch is one case in ext4_multi_mount_protect() and that can call sb_getblk() on its own. That way we can also simplify read_mmp_block() prototype to: static int read_mmp_block(struct super_block *sb, struct buffer_head *bh); Signed-off-by: Ye Bin Reviewed-by: Jan Kara --- fs/ext4/mmp.c | 44 +++++++++++++++++++------------------------- 1 file changed, 19 insertions(+), 25 deletions(-) diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c index 9788c617e593..3a7370c88934 100644 --- a/fs/ext4/mmp.c +++ b/fs/ext4/mmp.c @@ -64,33 +64,26 @@ static int write_mmp_block(struct super_block *sb, struct buffer_head *bh) /* * Read the MMP block. It _must_ be read from disk and hence we clear the * uptodate flag on the buffer. + * Caller must ensure pass valid 'bh'. */ -static int read_mmp_block(struct super_block *sb, struct buffer_head **bh, - ext4_fsblk_t mmp_block) +static int read_mmp_block(struct super_block *sb, struct buffer_head *bh) { struct mmp_struct *mmp; int ret; - if (*bh) - clear_buffer_uptodate(*bh); - - /* This would be sb_bread(sb, mmp_block), except we need to be sure - * that the MD RAID device cache has been bypassed, and that the read - * is not blocked in the elevator. */ - if (!*bh) { - *bh = sb_getblk(sb, mmp_block); - if (!*bh) { - ret = -ENOMEM; - goto warn_exit; - } + if (!bh) { + ret = -EINVAL; + goto warn_exit; } - lock_buffer(*bh); - ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL); + clear_buffer_uptodate(bh); + + lock_buffer(bh); + ret = ext4_read_bh(bh, REQ_META | REQ_PRIO, NULL); if (ret) goto warn_exit; - mmp = (struct mmp_struct *)((*bh)->b_data); + mmp = (struct mmp_struct *)((bh)->b_data); if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC) { ret = -EFSCORRUPTED; goto warn_exit; @@ -101,10 +94,7 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh, } return 0; warn_exit: - brelse(*bh); - *bh = NULL; - ext4_warning(sb, "Error %d while reading MMP block %llu", - ret, mmp_block); + ext4_warning(sb, "Error %d while reading MMP block", ret); return ret; } @@ -195,7 +185,7 @@ static int kmmpd(void *data) */ diff = jiffies - last_update_time; if (diff > mmp_check_interval * HZ) { - retval = read_mmp_block(sb, &bh, mmp_block); + retval = read_mmp_block(sb, bh); if (retval) { ext4_error_err(sb, -retval, "error reading MMP data: %d", @@ -289,7 +279,11 @@ int ext4_multi_mount_protect(struct super_block *sb, goto failed; } - retval = read_mmp_block(sb, &bh, mmp_block); + bh = sb_getblk(sb, mmp_block); + if (bh) + goto failed; + + retval = read_mmp_block(sb, bh); if (retval) goto failed; @@ -327,7 +321,7 @@ int ext4_multi_mount_protect(struct super_block *sb, goto failed; } - retval = read_mmp_block(sb, &bh, mmp_block); + retval = read_mmp_block(sb, bh); if (retval) goto failed; mmp = (struct mmp_struct *)(bh->b_data); @@ -356,7 +350,7 @@ int ext4_multi_mount_protect(struct super_block *sb, goto failed; } - retval = read_mmp_block(sb, &bh, mmp_block); + retval = read_mmp_block(sb, bh); if (retval) goto failed; mmp = (struct mmp_struct *)(bh->b_data);