From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:46387 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S969604AbdIZO1q (ORCPT ); Tue, 26 Sep 2017 10:27:46 -0400 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8395EAC1B for ; Tue, 26 Sep 2017 14:27:45 +0000 (UTC) From: Nikolay Borisov To: linux-btrfs@vger.kernel.org Cc: fdmanana@suse.com, Nikolay Borisov Subject: [RFC PATCH 2/2] btrfs: Remove received_uuid during received snapshot ro->rw switch Date: Tue, 26 Sep 2017 17:27:42 +0300 Message-Id: <1506436062-23825-2-git-send-email-nborisov@suse.com> In-Reply-To: <1506436062-23825-1-git-send-email-nborisov@suse.com> References: <1506436062-23825-1-git-send-email-nborisov@suse.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: Currently when a read-only snapshot is received and subsequently its ro property is set to false i.e. switched to rw-mode the received_uuid of that subvol remains intact. However, once the received volume is switched to RW mode we cannot guaranteee that it contains the same data, so it makes sense to remove the received uuid. Signed-off-by: Nikolay Borisov --- This patch has been inspired by the problem described in https://www.spinics.net/lists/linux-btrfs/msg68879.html fs/btrfs/ioctl.c | 37 ++++++++++++++++++++++++++++--------- 1 file changed, 28 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 09fcd51f0e8c..71fd28caefdd 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1811,6 +1811,17 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file, goto out_drop_sem; root_flags = btrfs_root_flags(&root->root_item); + + /* + * 1 - root item + * 1 - uuid item + */ + trans = btrfs_start_transaction(root, 2); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + goto out_drop_sem; + } + if (flags & BTRFS_SUBVOL_RDONLY) { btrfs_set_root_flags(&root->root_item, root_flags | BTRFS_ROOT_SUBVOL_RDONLY); @@ -1824,30 +1835,38 @@ static noinline int btrfs_ioctl_subvol_setflags(struct file *file, btrfs_set_root_flags(&root->root_item, root_flags & ~BTRFS_ROOT_SUBVOL_RDONLY); spin_unlock(&root->root_item_lock); + if (!btrfs_is_empty_uuid(root->root_item.received_uuid)) { + ret = btrfs_uuid_tree_rem(trans, fs_info, + root->root_item.received_uuid, + BTRFS_UUID_KEY_RECEIVED_SUBVOL, + root->root_key.objectid); + + if (ret && ret != -ENOENT) { + btrfs_abort_transaction(trans, ret); + goto out_end_trans; + } + + memset(root->root_item.received_uuid, 0, + BTRFS_UUID_SIZE); + } } else { spin_unlock(&root->root_item_lock); btrfs_warn(fs_info, "Attempt to set subvolume %llu read-write during send", root->root_key.objectid); ret = -EPERM; - goto out_drop_sem; + btrfs_abort_transaction(trans, ret); + goto out_end_trans; } } - trans = btrfs_start_transaction(root, 1); - if (IS_ERR(trans)) { - ret = PTR_ERR(trans); - goto out_reset; - } - ret = btrfs_update_root(trans, fs_info->tree_root, &root->root_key, &root->root_item); if (ret < 0) btrfs_abort_transaction(trans, ret); +out_end_trans: btrfs_commit_transaction(trans); - -out_reset: if (ret) btrfs_set_root_flags(&root->root_item, root_flags); out_drop_sem: -- 2.7.4