From patchwork Wed Oct 11 18:13:30 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liu Bo X-Patchwork-Id: 10000385 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id EC75C602BF for ; Wed, 11 Oct 2017 19:15:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D42D71FFAD for ; Wed, 11 Oct 2017 19:15:33 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C8DBD28B3E; Wed, 11 Oct 2017 19:15:33 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BC71F1FFAD for ; Wed, 11 Oct 2017 19:15:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757868AbdJKTPa (ORCPT ); Wed, 11 Oct 2017 15:15:30 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:28027 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753309AbdJKTP3 (ORCPT ); Wed, 11 Oct 2017 15:15:29 -0400 Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id v9BJFTjG019682 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 11 Oct 2017 19:15:29 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id v9BJFSAD018618 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Wed, 11 Oct 2017 19:15:28 GMT Received: from abhmp0007.oracle.com (abhmp0007.oracle.com [141.146.116.13]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id v9BJFSwA013938 for ; Wed, 11 Oct 2017 19:15:28 GMT Received: from dhcp-10-211-47-181.usdhcp.oraclecorp.com.com (/10.211.47.181) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 11 Oct 2017 12:15:28 -0700 From: Liu Bo To: linux-btrfs@vger.kernel.org Subject: [PATCH v2] Btrfs: free btrfs_device in place Date: Wed, 11 Oct 2017 12:13:30 -0600 Message-Id: <20171011181330.17015-1-bo.li.liu@oracle.com> X-Mailer: git-send-email 2.9.4 In-Reply-To: <20171010215103.20828-2-bo.li.liu@oracle.com> References: <20171010215103.20828-2-bo.li.liu@oracle.com> X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP It's pointless to defer it to a kthread helper as we're not under any special context. A bit more about device's lifetime, filesystems use an exclusive way to access devices and hold a reference count on the devices in use. Now that we've run blkdev_put() in btrfs_close_bdev(), device->bdev's lifetime ends at btrfs_close_bdev(), not free_device(), and %bdev is the only thing that others who need to access it really care about. Since free_device() only frees the resources of 'struct btrfs_device', this change won't result in the problem, ie. others like mkfs and md are unable to access the device immediately after we do umount. Signed-off-by: Liu Bo Reviewed-by: Anand Jain --- v2: Clarify the lifetime of device and device->bdev respectively and clear the concern about raising the 'device is in use' problem. fs/btrfs/volumes.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index d983cea..4a72c45 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -836,26 +836,16 @@ void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step) mutex_unlock(&uuid_mutex); } -static void __free_device(struct work_struct *work) +static void free_device(struct rcu_head *head) { struct btrfs_device *device; - device = container_of(work, struct btrfs_device, rcu_work); + device = container_of(head, struct btrfs_device, rcu); rcu_string_free(device->name); bio_put(device->flush_bio); kfree(device); } -static void free_device(struct rcu_head *head) -{ - struct btrfs_device *device; - - device = container_of(head, struct btrfs_device, rcu); - - INIT_WORK(&device->rcu_work, __free_device); - schedule_work(&device->rcu_work); -} - static void btrfs_close_bdev(struct btrfs_device *device) { if (device->bdev && device->writeable) {