From patchwork Mon Aug 17 15:12:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 266452 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 046D7C433DF for ; Mon, 17 Aug 2020 15:44:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B328C20760 for ; Mon, 17 Aug 2020 15:44:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597679087; bh=ennhsl72JIfwXruWZfItgNWSZh7AZzhHO7YlSTF7RGo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bXqZMHPivkFafQcWJE6EbS/JIZDlUvRdw6HIZl2sJlDdwPlDz9oo3aPvjAqt3IGL/ xsLUbQ1qvbRBoY4zYmUbM/zTzFWld3EwzgYAAeBpLBtpf8HhEECiG4pVhsNraXEIBA qZXTD/AkokyRUjJnjup9v1zvOO8dkw0lj0fZWXks= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387696AbgHQPoj (ORCPT ); Mon, 17 Aug 2020 11:44:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:55336 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730496AbgHQPod (ORCPT ); Mon, 17 Aug 2020 11:44:33 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B00DC22D01; Mon, 17 Aug 2020 15:44:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597679072; bh=ennhsl72JIfwXruWZfItgNWSZh7AZzhHO7YlSTF7RGo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jXJ0gvOtOwzCTxEOo+IX2XfOe8aMGxLSe1jc8uZUGmj96UFQrRxgFtL+i9f25ILBx WjvE0iQZhrJo5jOe18pd0Qv4IMeFGnGK73lF6tGeyCOO0udbBto2VpFTXbAuto4tdg 3u8F3PZV2WbVdIiF4G09/XJBmvoowYAFy7Q4KwTw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josef Bacik , David Sterba , Sasha Levin Subject: [PATCH 5.7 085/393] btrfs: fix lockdep splat from btrfs_dump_space_info Date: Mon, 17 Aug 2020 17:12:15 +0200 Message-Id: <20200817143823.753963587@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143819.579311991@linuxfoundation.org> References: <20200817143819.579311991@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Josef Bacik [ Upstream commit ab0db043c35da3477e57d4d516492b2d51a5ca0f ] When running with -o enospc_debug you can get the following splat if one of the dump_space_info's trip ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc5+ #20 Tainted: G OE ------------------------------------------------------ dd/563090 is trying to acquire lock: ffff9e7dbf4f1e18 (&ctl->tree_lock){+.+.}-{2:2}, at: btrfs_dump_free_space+0x2b/0xa0 [btrfs] but task is already holding lock: ffff9e7e2284d428 (&cache->lock){+.+.}-{2:2}, at: btrfs_dump_space_info+0xaa/0x120 [btrfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&cache->lock){+.+.}-{2:2}: _raw_spin_lock+0x25/0x30 btrfs_add_reserved_bytes+0x3c/0x3c0 [btrfs] find_free_extent+0x7ef/0x13b0 [btrfs] btrfs_reserve_extent+0x9b/0x180 [btrfs] btrfs_alloc_tree_block+0xc1/0x340 [btrfs] alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs] __btrfs_cow_block+0x122/0x530 [btrfs] btrfs_cow_block+0x106/0x210 [btrfs] commit_cowonly_roots+0x55/0x300 [btrfs] btrfs_commit_transaction+0x4ed/0xac0 [btrfs] sync_filesystem+0x74/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x36/0x70 cleanup_mnt+0x104/0x160 task_work_run+0x5f/0x90 __prepare_exit_to_usermode+0x1bd/0x1c0 do_syscall_64+0x5e/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&space_info->lock){+.+.}-{2:2}: _raw_spin_lock+0x25/0x30 btrfs_block_rsv_release+0x1a6/0x3f0 [btrfs] btrfs_inode_rsv_release+0x4f/0x170 [btrfs] btrfs_clear_delalloc_extent+0x155/0x480 [btrfs] clear_state_bit+0x81/0x1a0 [btrfs] __clear_extent_bit+0x25c/0x5d0 [btrfs] clear_extent_bit+0x15/0x20 [btrfs] btrfs_invalidatepage+0x2b7/0x3c0 [btrfs] truncate_cleanup_page+0x47/0xe0 truncate_inode_pages_range+0x238/0x840 truncate_pagecache+0x44/0x60 btrfs_setattr+0x202/0x5e0 [btrfs] notify_change+0x33b/0x490 do_truncate+0x76/0xd0 path_openat+0x687/0xa10 do_filp_open+0x91/0x100 do_sys_openat2+0x215/0x2d0 do_sys_open+0x44/0x80 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&tree->lock#2){+.+.}-{2:2}: _raw_spin_lock+0x25/0x30 find_first_extent_bit+0x32/0x150 [btrfs] write_pinned_extent_entries.isra.0+0xc5/0x100 [btrfs] __btrfs_write_out_cache+0x172/0x480 [btrfs] btrfs_write_out_cache+0x7a/0xf0 [btrfs] btrfs_write_dirty_block_groups+0x286/0x3b0 [btrfs] commit_cowonly_roots+0x245/0x300 [btrfs] btrfs_commit_transaction+0x4ed/0xac0 [btrfs] close_ctree+0xf9/0x2f5 [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x36/0x70 cleanup_mnt+0x104/0x160 task_work_run+0x5f/0x90 __prepare_exit_to_usermode+0x1bd/0x1c0 do_syscall_64+0x5e/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&ctl->tree_lock){+.+.}-{2:2}: __lock_acquire+0x1240/0x2460 lock_acquire+0xab/0x360 _raw_spin_lock+0x25/0x30 btrfs_dump_free_space+0x2b/0xa0 [btrfs] btrfs_dump_space_info+0xf4/0x120 [btrfs] btrfs_reserve_extent+0x176/0x180 [btrfs] __btrfs_prealloc_file_range+0x145/0x550 [btrfs] cache_save_setup+0x28d/0x3b0 [btrfs] btrfs_start_dirty_block_groups+0x1fc/0x4f0 [btrfs] btrfs_commit_transaction+0xcc/0xac0 [btrfs] btrfs_alloc_data_chunk_ondemand+0x162/0x4c0 [btrfs] btrfs_check_data_free_space+0x4c/0xa0 [btrfs] btrfs_buffered_write.isra.0+0x19b/0x740 [btrfs] btrfs_file_write_iter+0x3cf/0x610 [btrfs] new_sync_write+0x11e/0x1b0 vfs_write+0x1c9/0x200 ksys_write+0x68/0xe0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &ctl->tree_lock --> &space_info->lock --> &cache->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&cache->lock); lock(&space_info->lock); lock(&cache->lock); lock(&ctl->tree_lock); *** DEADLOCK *** 6 locks held by dd/563090: #0: ffff9e7e21d18448 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x195/0x200 #1: ffff9e7dd0410ed8 (&sb->s_type->i_mutex_key#19){++++}-{3:3}, at: btrfs_file_write_iter+0x86/0x610 [btrfs] #2: ffff9e7e21d18638 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40b/0x5b0 [btrfs] #3: ffff9e7e1f05d688 (&cur_trans->cache_write_mutex){+.+.}-{3:3}, at: btrfs_start_dirty_block_groups+0x158/0x4f0 [btrfs] #4: ffff9e7e2284ddb8 (&space_info->groups_sem){++++}-{3:3}, at: btrfs_dump_space_info+0x69/0x120 [btrfs] #5: ffff9e7e2284d428 (&cache->lock){+.+.}-{2:2}, at: btrfs_dump_space_info+0xaa/0x120 [btrfs] stack backtrace: CPU: 3 PID: 563090 Comm: dd Tainted: G OE 5.8.0-rc5+ #20 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./890FX Deluxe5, BIOS P1.40 05/03/2011 Call Trace: dump_stack+0x96/0xd0 check_noncircular+0x162/0x180 __lock_acquire+0x1240/0x2460 ? wake_up_klogd.part.0+0x30/0x40 lock_acquire+0xab/0x360 ? btrfs_dump_free_space+0x2b/0xa0 [btrfs] _raw_spin_lock+0x25/0x30 ? btrfs_dump_free_space+0x2b/0xa0 [btrfs] btrfs_dump_free_space+0x2b/0xa0 [btrfs] btrfs_dump_space_info+0xf4/0x120 [btrfs] btrfs_reserve_extent+0x176/0x180 [btrfs] __btrfs_prealloc_file_range+0x145/0x550 [btrfs] ? btrfs_qgroup_reserve_data+0x1d/0x60 [btrfs] cache_save_setup+0x28d/0x3b0 [btrfs] btrfs_start_dirty_block_groups+0x1fc/0x4f0 [btrfs] btrfs_commit_transaction+0xcc/0xac0 [btrfs] ? start_transaction+0xe0/0x5b0 [btrfs] btrfs_alloc_data_chunk_ondemand+0x162/0x4c0 [btrfs] btrfs_check_data_free_space+0x4c/0xa0 [btrfs] btrfs_buffered_write.isra.0+0x19b/0x740 [btrfs] ? ktime_get_coarse_real_ts64+0xa8/0xd0 ? trace_hardirqs_on+0x1c/0xe0 btrfs_file_write_iter+0x3cf/0x610 [btrfs] new_sync_write+0x11e/0x1b0 vfs_write+0x1c9/0x200 ksys_write+0x68/0xe0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is because we're holding the block_group->lock while trying to dump the free space cache. However we don't need this lock, we just need it to read the values for the printk, so move the free space cache dumping outside of the block group lock. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/space-info.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 756950aba1a66..317d1d2160090 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -468,8 +468,8 @@ void btrfs_dump_space_info(struct btrfs_fs_info *fs_info, "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s", cache->start, cache->length, cache->used, cache->pinned, cache->reserved, cache->ro ? "[readonly]" : ""); - btrfs_dump_free_space(cache, bytes); spin_unlock(&cache->lock); + btrfs_dump_free_space(cache, bytes); } if (++index < BTRFS_NR_RAID_TYPES) goto again;