Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934296AbaFJAWO (ORCPT ); Mon, 9 Jun 2014 20:22:14 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58239 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754347AbaFJAWI (ORCPT ); Mon, 9 Jun 2014 20:22:08 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Graf , Rusty Russell , Ben Hutchings , Yijing Wang Subject: [PATCH 3.4 50/88] virtio-blk: Dont free ida when disk is in use Date: Mon, 9 Jun 2014 17:25:00 -0700 Message-Id: <20140610002426.188652816@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140610002424.500996570@linuxfoundation.org> References: <20140610002424.500996570@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Graf commit f4953fe6c4aeada2d5cafd78aa97587a46d2d8f9 upstream. When a file system is mounted on a virtio-blk disk, we then remove it and then reattach it, the reattached disk gets the same disk name and ids as the hot removed one. This leads to very nasty effects - mostly rendering the newly attached device completely unusable. Trying what happens when I do the same thing with a USB device, I saw that the sd node simply doesn't get free'd when a device gets forcefully removed. Imitate the same behavior for vd devices. This way broken vd devices simply are never free'd and newly attached ones keep working just fine. Signed-off-by: Alexander Graf Signed-off-by: Rusty Russell Signed-off-by: Ben Hutchings Cc: Yijing Wang Signed-off-by: Greg Kroah-Hartman --- drivers/block/virtio_blk.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -573,6 +573,7 @@ static void __devexit virtblk_remove(str { struct virtio_blk *vblk = vdev->priv; int index = vblk->index; + int refc; /* Prevent config work handler from accessing the device. */ mutex_lock(&vblk->config_lock); @@ -587,11 +588,15 @@ static void __devexit virtblk_remove(str flush_work(&vblk->config_work); + refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); put_disk(vblk->disk); mempool_destroy(vblk->pool); vdev->config->del_vqs(vdev); kfree(vblk); - ida_simple_remove(&vd_index_ida, index); + + /* Only free device id if we don't have any users */ + if (refc == 1) + ida_simple_remove(&vd_index_ida, index); } #ifdef CONFIG_PM -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/