From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F7B0CCA47B for ; Mon, 11 Jul 2022 09:51:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233948AbiGKJvh (ORCPT ); Mon, 11 Jul 2022 05:51:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233809AbiGKJui (ORCPT ); Mon, 11 Jul 2022 05:50:38 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7C50248FF; Mon, 11 Jul 2022 02:24:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4E6B66112E; Mon, 11 Jul 2022 09:24:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 633D7C341C0; Mon, 11 Jul 2022 09:24:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657531496; bh=yZtrHS6oc+q1zJ4xFjTvui4hoYjxxt2NUH81KemFZrI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sYT2OHsaeYfS9NUWDXqu8O/qxAN7rXGPM7/ujrxr+waDRqnpkUrosrtoJVvuhocn+ 7W38AwrD/95Bb0R/aMj7KakiOzyV+3VdZjJ6W8pYB3NYg6ouG1ZokZRQ7wHZ1eXT++ Pe4DmHSFRpBdTKfJrvSk59tmh/faQbBjSImgwyQk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Thumshirn , Naohiro Aota , David Sterba , Sasha Levin Subject: [PATCH 5.15 125/230] btrfs: zoned: use dedicated lock for data relocation Date: Mon, 11 Jul 2022 11:06:21 +0200 Message-Id: <20220711090607.610632602@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220711090604.055883544@linuxfoundation.org> References: <20220711090604.055883544@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Naohiro Aota [ Upstream commit 5f0addf7b89085f8e0a2593faa419d6111612b9b ] Currently, we use btrfs_inode_{lock,unlock}() to grant an exclusive writeback of the relocation data inode in btrfs_zoned_data_reloc_{lock,unlock}(). However, that can cause a deadlock in the following path. Thread A takes btrfs_inode_lock() and waits for metadata reservation by e.g, waiting for writeback: prealloc_file_extent_cluster() - btrfs_inode_lock(&inode->vfs_inode, 0); - btrfs_prealloc_file_range() ... - btrfs_replace_file_extents() - btrfs_start_transaction ... - btrfs_reserve_metadata_bytes() Thread B (e.g, doing a writeback work) needs to wait for the inode lock to continue writeback process: do_writepages - btrfs_writepages - extent_writpages - btrfs_zoned_data_reloc_lock(BTRFS_I(inode)); - btrfs_inode_lock() The deadlock is caused by relying on the vfs_inode's lock. By using it, we introduced unnecessary exclusion of writeback and btrfs_prealloc_file_range(). Also, the lock at this point is useless as we don't have any dirty pages in the inode yet. Introduce fs_info->zoned_data_reloc_io_lock and use it for the exclusive writeback. Fixes: 35156d852762 ("btrfs: zoned: only allow one process to add pages to a relocation inode") CC: stable@vger.kernel.org # 5.16.x: 869f4cdc73f9: btrfs: zoned: encapsulate inode locking for zoned relocation CC: stable@vger.kernel.org # 5.16.x CC: stable@vger.kernel.org # 5.17 Cc: Johannes Thumshirn Reviewed-by: Johannes Thumshirn Signed-off-by: Naohiro Aota Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/ctree.h | 1 + fs/btrfs/disk-io.c | 1 + fs/btrfs/zoned.h | 4 ++-- 3 files changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index cc72d8981c47..d1838de0b39c 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1027,6 +1027,7 @@ struct btrfs_fs_info { */ spinlock_t relocation_bg_lock; u64 data_reloc_bg; + struct mutex zoned_data_reloc_io_lock; #ifdef CONFIG_BTRFS_FS_REF_VERIFY spinlock_t ref_verify_lock; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 233d894f6feb..909d19656316 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2914,6 +2914,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info) mutex_init(&fs_info->reloc_mutex); mutex_init(&fs_info->delalloc_root_mutex); mutex_init(&fs_info->zoned_meta_io_lock); + mutex_init(&fs_info->zoned_data_reloc_io_lock); seqlock_init(&fs_info->profiles_lock); INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots); diff --git a/fs/btrfs/zoned.h b/fs/btrfs/zoned.h index d680c3ee918a..3a826f7c2040 100644 --- a/fs/btrfs/zoned.h +++ b/fs/btrfs/zoned.h @@ -330,7 +330,7 @@ static inline void btrfs_zoned_data_reloc_lock(struct btrfs_inode *inode) struct btrfs_root *root = inode->root; if (btrfs_is_data_reloc_root(root) && btrfs_is_zoned(root->fs_info)) - btrfs_inode_lock(&inode->vfs_inode, 0); + mutex_lock(&root->fs_info->zoned_data_reloc_io_lock); } static inline void btrfs_zoned_data_reloc_unlock(struct btrfs_inode *inode) @@ -338,7 +338,7 @@ static inline void btrfs_zoned_data_reloc_unlock(struct btrfs_inode *inode) struct btrfs_root *root = inode->root; if (btrfs_is_data_reloc_root(root) && btrfs_is_zoned(root->fs_info)) - btrfs_inode_unlock(&inode->vfs_inode, 0); + mutex_unlock(&root->fs_info->zoned_data_reloc_io_lock); } #endif -- 2.35.1