From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 01AFE30C37D; Mon, 18 Aug 2025 13:42:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755524540; cv=none; b=OM1g617Ci7KELEvFLhl4F9/OOyvqGFAefDR6YyFidKDRFVMIXu1oInf2dL+IX2+nwpiVhJbDs2OBSKWveEDvup6igWbz3HHuWWesd+EHAI9c4oo8MPVrDQ6XUfxwW/EcLbMt51yglW+EtQjdCJUuAjzILsBO3DxvYOz3KROK7aw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755524540; c=relaxed/simple; bh=Gvk3ywyxTn02MVbFKPjtSPoDtdbMb/vwSirCps4vIbM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZJL0aRWYrYGUwPThCdQKQFwjKO6a/XGG2ZKf2+mBZ3ZWFBhoauyIJQPmRT4w8WJCUyVYIMKUxNAJpVrYSf1nxasCnaNbb8UE5yK+YV/Pb/dAsGrMDXInCFLfpGZaQwHk+mlT/JR62/lvI9zZqEKek1VkfFQLzwMXbetb1zqJZOY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lFEy2gvH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lFEy2gvH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37827C4CEEB; Mon, 18 Aug 2025 13:42:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755524539; bh=Gvk3ywyxTn02MVbFKPjtSPoDtdbMb/vwSirCps4vIbM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lFEy2gvHOItZ1+hHFudbyMYBEXTUAXiYYs5GPwyTNLFxv4Nz7lNF5oZeeBC7PAPMJ VGXpYgBK53tm4OhXEj7jhWpTQW/4IYb0rMW5UxXi/FLPj9HqUW6tvgdV4LBWAlqgWS UxUXoY749pGLU1fguWsfbtO8sJ/rRR7vJIbhuyEA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qu Wenruo , Filipe Manana , David Sterba Subject: [PATCH 6.15 472/515] btrfs: qgroup: fix qgroup create ioctl returning success after quotas disabled Date: Mon, 18 Aug 2025 14:47:38 +0200 Message-ID: <20250818124516.591415449@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250818124458.334548733@linuxfoundation.org> References: <20250818124458.334548733@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Filipe Manana commit 08530d6e638427e7e1344bd67bacc03882ba95b9 upstream. When quotas are disabled qgroup ioctls are supposed to return -ENOTCONN, but the qgroup create ioctl stopped doing that when it races with a quota disable operation, returning 0 instead. This change of behaviour happened in commit 6ed05643ddb1 ("btrfs: create qgroup earlier in snapshot creation"). The issue happens as follows: 1) Task A enters btrfs_ioctl_qgroup_create(), qgroups are enabled and so qgroup_enabled() returns true since fs_info->quota_root is not NULL; 2) Task B enters btrfs_ioctl_quota_ctl() -> btrfs_quota_disable() and disables qgroups, so now fs_info->quota_root is NULL; 3) Task A enters btrfs_create_qgroup() and calls btrfs_qgroup_mode(), which returns BTRFS_QGROUP_MODE_DISABLED since quotas are disabled, and then btrfs_create_qgroup() returns 0 to the caller, which makes the ioctl return 0 instead of -ENOTCONN. The check for fs_info->quota_root and returning -ENOTCONN if it's NULL is made only after the call btrfs_qgroup_mode(). Fix this by moving the check for disabled quotas with btrfs_qgroup_mode() into transaction.c:create_pending_snapshot(), so that we don't abort the transaction if btrfs_create_qgroup() returns -ENOTCONN and quotas are disabled. Fixes: 6ed05643ddb1 ("btrfs: create qgroup earlier in snapshot creation") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Qu Wenruo Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/qgroup.c | 3 --- fs/btrfs/transaction.c | 6 ++++-- 2 files changed, 4 insertions(+), 5 deletions(-) --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1690,9 +1690,6 @@ int btrfs_create_qgroup(struct btrfs_tra struct btrfs_qgroup *prealloc = NULL; int ret = 0; - if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED) - return 0; - mutex_lock(&fs_info->qgroup_ioctl_lock); if (!fs_info->quota_root) { ret = -ENOTCONN; --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1736,8 +1736,10 @@ static noinline int create_pending_snaps ret = btrfs_create_qgroup(trans, objectid); if (ret && ret != -EEXIST) { - btrfs_abort_transaction(trans, ret); - goto fail; + if (ret != -ENOTCONN || btrfs_qgroup_enabled(fs_info)) { + btrfs_abort_transaction(trans, ret); + goto fail; + } } /*