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 5C394C433EF for ; Mon, 2 May 2022 17:19:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1386657AbiEBRWs (ORCPT ); Mon, 2 May 2022 13:22:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378055AbiEBRWp (ORCPT ); Mon, 2 May 2022 13:22:45 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A7DBA1B3 for ; Mon, 2 May 2022 10:19:16 -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 D12E7613FB for ; Mon, 2 May 2022 17:19:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33AEBC385B1; Mon, 2 May 2022 17:19:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651511955; bh=c5MuQ/JXRiVLbhhiyknX1S3uoFCryf9542M7F64eTww=; h=Subject:To:Cc:From:Date:From; b=fgjkD5Yz5Wh+9nwQC2Zk5ebKNd8zPp9nb9t1WwQkFhA1fy2v3LKBwohoUHISOZXkV BP+xdZsy99+okYZiYh+jGvKbSz+9i4M8Hn7q+2y6SE+GZtQxLceMppKTjc8Xg4ghH/ P7CnsaRiTlRO6MU5BafJVkmINVP5lCDzdEsqTwqc= Subject: FAILED: patch "[PATCH] btrfs: zoned: use dedicated lock for data relocation" failed to apply to 5.15-stable tree To: naohiro.aota@wdc.com, dsterba@suse.com, johannes.thumshirn@wdc.com Cc: From: Date: Mon, 02 May 2022 19:19:10 +0200 Message-ID: <165151195021699@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5f0addf7b89085f8e0a2593faa419d6111612b9b Mon Sep 17 00:00:00 2001 From: Naohiro Aota Date: Mon, 18 Apr 2022 16:15:03 +0900 Subject: [PATCH] btrfs: zoned: use dedicated lock for data relocation 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 diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 4db17bd05a21..604a4d54cf0d 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1060,6 +1060,7 @@ struct btrfs_fs_info { */ spinlock_t relocation_bg_lock; u64 data_reloc_bg; + struct mutex zoned_data_reloc_io_lock; u64 nr_global_roots; diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index cebd7a78c964..20e70eb88465 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3156,6 +3156,7 @@ 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 cbf016a7bb5d..6dee76248cb4 100644 --- a/fs/btrfs/zoned.h +++ b/fs/btrfs/zoned.h @@ -359,7 +359,7 @@ 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) @@ -367,7 +367,7 @@ 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