From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2120.oracle.com ([141.146.126.78]:47146 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727653AbeGPPWq (ORCPT ); Mon, 16 Jul 2018 11:22:46 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w6GEs8fZ066834 for ; Mon, 16 Jul 2018 14:54:59 GMT Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp2120.oracle.com with ESMTP id 2k7a33vshb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Mon, 16 Jul 2018 14:54:58 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w6GEsvZc007564 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Mon, 16 Jul 2018 14:54:58 GMT Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w6GEsv41012385 for ; Mon, 16 Jul 2018 14:54:57 GMT From: Anand Jain To: linux-btrfs@vger.kernel.org Subject: [PATCH 3/7] btrfs: do device clone using the btrfs_scan_one_device Date: Mon, 16 Jul 2018 22:58:08 +0800 Message-Id: <20180716145812.20836-4-anand.jain@oracle.com> In-Reply-To: <20180716145812.20836-1-anand.jain@oracle.com> References: <20180716145812.20836-1-anand.jain@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: When we add a device to the RO mounted seed device, it becomes a RW sprout FS. The following steps are used to hold the seed and sprout fs_devices. (first two steps are not mandatory for the sprouting, they are there to ensure the seed device remains in the scanned state) . Clone the (mounted) fs_devices, lets call it as old_devices . Now add old_devices to fs_uuids (yeah, there is duplicate fsid in the list, as we are under uuid_mutex so its fine). . Alloc a new fs_devices, lets call it as seed_devices . Copy fs_devices into the seed_devices . Move fs_devices::devices into seed_devices::devices . Bring seed_devices to under fs_devices::seed (fs_devices->seed = seed_devices) . Assign a new FSID to the fs_devices and add the new writable device to the fs_devices. This patch makes the following changes.. As we clone fs_devices to make sure the device remains scanned after the sprouting. So use the btrfs_scan_one_device() code instead. And do it at the end of the sprouting. Signed-off-by: Anand Jain --- fs/btrfs/volumes.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 8450bcfed4cb..c6f3f0dfbabe 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2179,7 +2179,7 @@ int btrfs_find_device_by_devspec(struct btrfs_fs_info *fs_info, u64 devid, static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info) { struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; - struct btrfs_fs_devices *old_devices; + struct btrfs_fs_devices *old_fs_devices; struct btrfs_fs_devices *seed_devices; struct btrfs_super_block *disk_super = fs_info->super_copy; struct btrfs_device *device; @@ -2193,14 +2193,6 @@ static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info) if (IS_ERR(seed_devices)) return PTR_ERR(seed_devices); - old_devices = clone_fs_devices(fs_devices); - if (IS_ERR(old_devices)) { - kfree(seed_devices); - return PTR_ERR(old_devices); - } - - list_add(&old_devices->fs_list, &fs_uuids); - memcpy(seed_devices, fs_devices, sizeof(*seed_devices)); seed_devices->opened = 1; INIT_LIST_HEAD(&seed_devices->devices); @@ -2233,6 +2225,17 @@ static int btrfs_prepare_sprout(struct btrfs_fs_info *fs_info) ~BTRFS_SUPER_FLAG_SEEDING; btrfs_set_super_flags(disk_super, super_flags); + /* + * As the above code hijacked the original seed fs_devices, now + * create a new one for the original seed FSID. + */ + list_for_each_entry(device, &fs_devices->seed->devices, dev_list) { + if (!device->name) + continue; + btrfs_scan_one_device(device->name->str, FMODE_READ, + fs_info->bdev_holder, &old_fs_devices); + } + return 0; } -- 2.7.0