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 D1CE335A297; Mon, 18 Aug 2025 14:13:59 +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=1755526439; cv=none; b=n7YFDLFdrFouQ3PP/ytbWDsX7HivoxdsAwrCDu52RBLUblSUaNtCu4fCHlS+5eFDyLnm23kkTMZeZ9idciWYxTPl1sZhcl9LdSOL9t07PYER16GAawKJzq2sVqIQDLlLJJUjS+slCYfwmPSLqCxdUaMaPJbiAj5ZBB6NzDkw8P0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755526439; c=relaxed/simple; bh=fyptKZTuHsQPTaxvL76jSBi+oi+1vl/uUCr5y5JZmdk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EoEoEZCHll73Irgm5pC79a3N6UOoPzTBpqY9KKR5hTbDJOEcDa15ZEtEPXo3dsFFr4Btfox0g9FgSe2AzUlkOscajzX/GV32bs2fMlgDQOEOb3V0UfvPxaLcy9nHxWt7E3X9AUAcIaXKcT0Q3Yj4aRf3kpibR9ayYxqQ+daYS9Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=l2A+qoa1; 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="l2A+qoa1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F2C4C4CEEB; Mon, 18 Aug 2025 14:13:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755526439; bh=fyptKZTuHsQPTaxvL76jSBi+oi+1vl/uUCr5y5JZmdk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l2A+qoa1sd94bGmFilh2FtB95skAQgHdQUifcx7sUuD/K17vQbdyVxkUHscmyC3VE OkUG9MSxFAG4P4TPNvhfB7nHV7uZ18RArKtCdWPUpMt7Hypp3qcTjjD/IvQHqgCUjK XFlPfgyjcUgI24XXzNiPuSQsBEFvvQR7TnoXLbic= 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 6.16 523/570] btrfs: qgroup: fix qgroup create ioctl returning success after quotas disabled Date: Mon, 18 Aug 2025 14:48:30 +0200 Message-ID: <20250818124526.014628694@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250818124505.781598737@linuxfoundation.org> References: <20250818124505.781598737@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 6.16-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 @@ -1735,8 +1735,10 @@ 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; + } } /*