From patchwork Mon Apr 18 05:50:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naohiro Aota X-Patchwork-Id: 12816315 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 05AC5C433EF for ; Mon, 18 Apr 2022 05:50:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236678AbiDRFxR (ORCPT ); Mon, 18 Apr 2022 01:53:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236148AbiDRFxR (ORCPT ); Mon, 18 Apr 2022 01:53:17 -0400 Received: from esa2.hgst.iphmx.com (esa2.hgst.iphmx.com [68.232.143.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2254C55A3 for ; Sun, 17 Apr 2022 22:50:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1650261038; x=1681797038; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=xoCMnmczuljhDtFeo3A0IFPvsEmbEiaihOA2cNgQvYo=; b=djcXnKpl2+lJ+7GIHpb+fa5I9T7xSs6pZ6tf96Hjj3wFEUpuz6W/NN4H irkXXbkQrKjNvg5N1FCbkDTIepB4Qy8EJ9KlmfWzec0uEJ9aIMokf4N/r 6NzAMPVXt7n1FqVu3QI+fH7Tsz50ZwbSCRRjSmwukLD6rKKH7XoMUaeup /L5/sDRcLPWZbC9DjMDEbgJL19LTaV/CCUZ6D6aJ/dWfA7HKGBp+YNoS8 /hHCHBxnRkd3Lcn/loMYNsehtdSEOQyI2AowUF0kYUROCU5NdQtnS2AmP xmMSjID4Tp922WkvxHLnyRMEJYvhuCJVRbniVQkbfUBHtUk3cNf8SLS+k w==; X-IronPort-AV: E=Sophos;i="5.90,267,1643644800"; d="scan'208";a="302331499" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 18 Apr 2022 13:50:32 +0800 IronPort-SDR: 8i9fN6O+/j46VsgFNJe7DQ9BogErPqdaSdv1G6/etOpgZkA41vXUgXxT4zjtyX1Au+yF5ndKOF BCHX7JRB5JD8Ojhs8C0oPn71h35QnkZRKkvQpviGj8XPyjnXrRhav9eGUWjUyKqw08ItU8u4Rl mDAu6G7/ESOHOXI5jLnPzwrOkaj0VfCq0FqF11fgqjFPnQiYhdl9BBkaAZfRc2G8o/WAXFx/tX mWuq4tKBAn0PjWtB4ol1Fu6q+QVCw8+tpwsW5GtKow6V4YxQ3s2vuVdIfU7C3L28WqYHJ/nKrd ULKxIJ0wCaIr23g9eKWmXJy1 Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 17 Apr 2022 22:20:51 -0700 IronPort-SDR: C4ANNov/CS3AgD9NDWjW1ozSlOHJtOLzcCmJGjfUZhOc3Wht/z9tgNV/4/89BmmCYkD46jCwtD 1B6teylCqosLoNkdtrSBnKVCy5nZoYnWBSgXNkroL1aWUeYZuoMm/wAQZYjRIiAq5QRuRDJaL8 z2560Oao7PDa3KaPhDH1xlXDpHo0ztksF0J1qbxxu2jGZItTK0l4fvQbAiuQaBX7M58aRr7fGi Y89nzmXwqHiPg4GYLON1c/zIGrw48lloldwfDHHFK/Q2sJmRPdeHwrTnlPtwrucoSpnZEAnpJX 9hY= WDCIronportException: Internal Received: from hfp4fb3.ad.shared (HELO naota-xeon.ad.shared) ([10.225.53.140]) by uls-op-cesaip01.wdc.com with ESMTP; 17 Apr 2022 22:50:30 -0700 From: Naohiro Aota To: linux-btrfs@vger.kernel.org Cc: johannes.thumshirn@wdc.com, Naohiro Aota Subject: [PATCH] btrfs: zoned: use dedicated lock for data relocation Date: Mon, 18 Apr 2022 14:50:20 +0900 Message-Id: <1ad4d3f6ed32ab2d3352adb6da7ba4ff049e79a0.1650257630.git.naohiro.aota@wdc.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 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. Signed-off-by: Naohiro Aota --- 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 55dee124ee44..580a392d7c37 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1056,6 +1056,7 @@ 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 2689e8589627..2a0284c2430e 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3179,6 +3179,7 @@ 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 fc2034e66ce3..de923fc8449d 100644 --- a/fs/btrfs/zoned.h +++ b/fs/btrfs/zoned.h @@ -361,7 +361,7 @@ 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) @@ -369,7 +369,7 @@ 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