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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 CE7D8CA9EBC for ; Fri, 25 Oct 2019 14:00:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6F03222C9 for ; Fri, 25 Oct 2019 14:00:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572012056; bh=la3xfm77mTHrN9MjZAExRmGreRCnVATFwQRG5TLWQBw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YScuBB0bQCsdGYPc84TuNWVC2fAdlhwgjYkqhZj2NsrtFF4dYi22SJkz0Z36rxKd9 OEygWh5BN68QxHWHexiEPmeePLxEfJHsV44+BsrU11rWGIDw7b8SWi8EgRALHdTMHJ jMszS4spuqoVNZoUYWyE7D+1/jXJSApGOB0MqEeA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394884AbfJYOAs (ORCPT ); Fri, 25 Oct 2019 10:00:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:53964 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2505607AbfJYN6d (ORCPT ); Fri, 25 Oct 2019 09:58:33 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DA202222D1; Fri, 25 Oct 2019 13:58:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572011912; bh=la3xfm77mTHrN9MjZAExRmGreRCnVATFwQRG5TLWQBw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mCbxsuwQn8nS1Bea2T4LpiiexmOI5stnsKUO9klI1FJZFG3hJNZKk+bTSGaDlP3Yh LqZ/iMSe5fCAwgVVAzNmxCbmdufKucxP10LIis+XhbxitaT92j7BJtyHM+x7OcpKwr tVHi9EbbAWxL3JpFz2Apys0BmjsL96tjPm3Q7668= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Filipe Manana , Nikolay Borisov , David Sterba , Sasha Levin , linux-btrfs@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 16/20] Btrfs: fix hang when loading existing inode cache off disk Date: Fri, 25 Oct 2019 09:57:56 -0400 Message-Id: <20191025135801.25739-16-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191025135801.25739-1-sashal@kernel.org> References: <20191025135801.25739-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: Filipe Manana [ Upstream commit 7764d56baa844d7f6206394f21a0e8c1f303c476 ] If we are able to load an existing inode cache off disk, we set the state of the cache to BTRFS_CACHE_FINISHED, but we don't wake up any one waiting for the cache to be available. This means that anyone waiting for the cache to be available, waiting on the condition that either its state is BTRFS_CACHE_FINISHED or its available free space is greather than zero, can hang forever. This could be observed running fstests with MOUNT_OPTIONS="-o inode_cache", in particular test case generic/161 triggered it very frequently for me, producing a trace like the following: [63795.739712] BTRFS info (device sdc): enabling inode map caching [63795.739714] BTRFS info (device sdc): disk space caching is enabled [63795.739716] BTRFS info (device sdc): has skinny extents [64036.653886] INFO: task btrfs-transacti:3917 blocked for more than 120 seconds. [64036.654079] Not tainted 5.2.0-rc4-btrfs-next-50 #1 [64036.654143] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [64036.654232] btrfs-transacti D 0 3917 2 0x80004000 [64036.654239] Call Trace: [64036.654258] ? __schedule+0x3ae/0x7b0 [64036.654271] schedule+0x3a/0xb0 [64036.654325] btrfs_commit_transaction+0x978/0xae0 [btrfs] [64036.654339] ? remove_wait_queue+0x60/0x60 [64036.654395] transaction_kthread+0x146/0x180 [btrfs] [64036.654450] ? btrfs_cleanup_transaction+0x620/0x620 [btrfs] [64036.654456] kthread+0x103/0x140 [64036.654464] ? kthread_create_worker_on_cpu+0x70/0x70 [64036.654476] ret_from_fork+0x3a/0x50 [64036.654504] INFO: task xfs_io:3919 blocked for more than 120 seconds. [64036.654568] Not tainted 5.2.0-rc4-btrfs-next-50 #1 [64036.654617] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [64036.654685] xfs_io D 0 3919 3633 0x00000000 [64036.654691] Call Trace: [64036.654703] ? __schedule+0x3ae/0x7b0 [64036.654716] schedule+0x3a/0xb0 [64036.654756] btrfs_find_free_ino+0xa9/0x120 [btrfs] [64036.654764] ? remove_wait_queue+0x60/0x60 [64036.654809] btrfs_create+0x72/0x1f0 [btrfs] [64036.654822] lookup_open+0x6bc/0x790 [64036.654849] path_openat+0x3bc/0xc00 [64036.654854] ? __lock_acquire+0x331/0x1cb0 [64036.654869] do_filp_open+0x99/0x110 [64036.654884] ? __alloc_fd+0xee/0x200 [64036.654895] ? do_raw_spin_unlock+0x49/0xc0 [64036.654909] ? do_sys_open+0x132/0x220 [64036.654913] do_sys_open+0x132/0x220 [64036.654926] do_syscall_64+0x60/0x1d0 [64036.654933] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix this by adding a wake_up() call right after setting the cache state to BTRFS_CACHE_FINISHED, at start_caching(), when we are able to load the cache from disk. Fixes: 82d5902d9c681b ("Btrfs: Support reading/writing on disk free ino cache") Reviewed-by: Nikolay Borisov Signed-off-by: Filipe Manana Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/inode-map.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c index d27014b8bf727..075b59516c8c0 100644 --- a/fs/btrfs/inode-map.c +++ b/fs/btrfs/inode-map.c @@ -159,6 +159,7 @@ static void start_caching(struct btrfs_root *root) spin_lock(&root->ino_cache_lock); root->ino_cache_state = BTRFS_CACHE_FINISHED; spin_unlock(&root->ino_cache_lock); + wake_up(&root->ino_cache_wait); return; } -- 2.20.1