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=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 D0C1FC3A5A2 for ; Tue, 3 Sep 2019 16:27:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8BB3238CF for ; Tue, 3 Sep 2019 16:27:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567528069; bh=K2zEh8HBO4tXSDQGVU8dQEtEWMQXYEZ9OIiPIbCR+Mg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Jt3rZnVgvobt2fFYU+kCK0kPkOOXK0FCcZKFjWG61Nba4XS+ioMaEn4lYefsW20El WC8zcQEhLGYjd0Ntj4vN4A/PYRDVGT4BxeX5ooRvVJiMyCxuif4QKfblnIddAmPOyl AF9+4RNN43onch3o0MiJWFslwOcnXVwxOF1De3T0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730956AbfICQ1s (ORCPT ); Tue, 3 Sep 2019 12:27:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:49238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730512AbfICQ1o (ORCPT ); Tue, 3 Sep 2019 12:27:44 -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 DFF14238C5; Tue, 3 Sep 2019 16:27:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567528063; bh=K2zEh8HBO4tXSDQGVU8dQEtEWMQXYEZ9OIiPIbCR+Mg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nHPLRYM/rzO/oTp06xz4RfAa7Bvye2PMHIjFf8aSHTqK4Ctn0VCVKsyjTklt1q68n 6EuHIKZp37zrbTKWsQ7Hit2dNKRYfwPMyN0MlqfAiB67XuCilAXXkoSddiH5mwBdA0 fsnxqnTP5YCM3KmIivIATLAUmfo5hWfYxk1VjBxM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: David Sterba , Sasha Levin , linux-btrfs@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 078/167] btrfs: scrub: move scrub_setup_ctx allocation out of device_list_mutex Date: Tue, 3 Sep 2019 12:23:50 -0400 Message-Id: <20190903162519.7136-78-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190903162519.7136-1-sashal@kernel.org> References: <20190903162519.7136-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Sterba [ Upstream commit 0e94c4f45d14cf89d1f40c91b0a8517e791672a7 ] The scrub context is allocated with GFP_KERNEL and called from btrfs_scrub_dev under the fs_info::device_list_mutex. This is not safe regarding reclaim that could try to flush filesystem data in order to get the memory. And the device_list_mutex is held during superblock commit, so this would cause a lockup. Move the alocation and initialization before any changes that require the mutex. Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/scrub.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index efaad3e1b295a..56c4d2236484f 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3837,13 +3837,18 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, return -EINVAL; } + /* Allocate outside of device_list_mutex */ + sctx = scrub_setup_ctx(fs_info, is_dev_replace); + if (IS_ERR(sctx)) + return PTR_ERR(sctx); mutex_lock(&fs_info->fs_devices->device_list_mutex); dev = btrfs_find_device(fs_info, devid, NULL, NULL); if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) && !is_dev_replace)) { mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return -ENODEV; + ret = -ENODEV; + goto out_free_ctx; } if (!is_dev_replace && !readonly && @@ -3851,7 +3856,8 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, mutex_unlock(&fs_info->fs_devices->device_list_mutex); btrfs_err_in_rcu(fs_info, "scrub: device %s is not writable", rcu_str_deref(dev->name)); - return -EROFS; + ret = -EROFS; + goto out_free_ctx; } mutex_lock(&fs_info->scrub_lock); @@ -3859,7 +3865,8 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) { mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return -EIO; + ret = -EIO; + goto out_free_ctx; } btrfs_dev_replace_read_lock(&fs_info->dev_replace); @@ -3869,7 +3876,8 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, btrfs_dev_replace_read_unlock(&fs_info->dev_replace); mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return -EINPROGRESS; + ret = -EINPROGRESS; + goto out_free_ctx; } btrfs_dev_replace_read_unlock(&fs_info->dev_replace); @@ -3877,16 +3885,9 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, if (ret) { mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return ret; + goto out_free_ctx; } - sctx = scrub_setup_ctx(fs_info, is_dev_replace); - if (IS_ERR(sctx)) { - mutex_unlock(&fs_info->scrub_lock); - mutex_unlock(&fs_info->fs_devices->device_list_mutex); - scrub_workers_put(fs_info); - return PTR_ERR(sctx); - } sctx->readonly = readonly; dev->scrub_ctx = sctx; mutex_unlock(&fs_info->fs_devices->device_list_mutex); @@ -3939,6 +3940,11 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, scrub_put_ctx(sctx); + return ret; + +out_free_ctx: + scrub_free_ctx(sctx); + return ret; } -- 2.20.1