From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1048 invoked by alias); 3 Aug 2010 07:56:04 -0000 Received: (qmail 1034 invoked by uid 9796); 3 Aug 2010 07:56:04 -0000 Date: Tue, 03 Aug 2010 07:56:00 -0000 Message-ID: <20100803075604.1030.qmail@sourceware.org> From: prajnoha@sourceware.org To: lvm-devel@redhat.com, lvm2-cvs@sourceware.org Subject: LVM2 ./WHATS_NEW_DM libdm/libdm-common.c Mailing-List: contact lvm2-cvs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: lvm2-cvs-owner@sourceware.org X-SW-Source: 2010-08/txt/msg00012.txt.bz2 CVSROOT: /cvs/lvm2 Module name: LVM2 Changes by: prajnoha@sourceware.org 2010-08-03 07:56:04 Modified files: . : WHATS_NEW_DM libdm : libdm-common.c Log message: Add check for kernel semaphore support and disable udev_sync if not available. udev_sync feature requires semaphores (part of System V IPC) to be configured in kernel (CONFIG_SYSVIPC). Check whether it is supported and if not, give a warning message and disable udev synchronisation code automatically to avoid any further error states and associated problems. One should use the kernel with System V IPC support enabled or libdevmapper with udev_sync feature disabled. Patches: http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/WHATS_NEW_DM.diff?cvsroot=lvm2&r1=1.400&r2=1.401 http://sourceware.org/cgi-bin/cvsweb.cgi/LVM2/libdm/libdm-common.c.diff?cvsroot=lvm2&r1=1.97&r2=1.98 --- LVM2/WHATS_NEW_DM 2010/07/28 21:58:08 1.400 +++ LVM2/WHATS_NEW_DM 2010/08/03 07:56:03 1.401 @@ -1,5 +1,6 @@ Version 1.02.54 - ================================ + Add check for kernel semaphore support and disable udev_sync if not available. Version 1.02.53 - 28th July 2010 ================================ --- LVM2/libdm/libdm-common.c 2010/07/09 15:34:47 1.97 +++ LVM2/libdm/libdm-common.c 2010/08/03 07:56:03 1.98 @@ -60,6 +60,7 @@ static int _verbose = 0; #ifdef UDEV_SYNC_SUPPORT +static int _semaphore_supported = -1; static int _udev_running = -1; static int _sync_with_udev = 1; static int _udev_checking = 1; @@ -929,6 +930,23 @@ #else /* UDEV_SYNC_SUPPORT */ +static int _check_semaphore_is_supported() +{ + int maxid; + union semun arg; + struct seminfo seminfo; + + arg.__buf = &seminfo; + maxid = semctl(0, 0, SEM_INFO, arg); + + if (maxid < 0) { + log_warn("Kernel not configured for semaphores (System V IPC). " + "Not using udev synchronisation code."); + return 0; + } + + return 1; +} static int _check_udev_is_running(void) { @@ -958,20 +976,27 @@ return 0; } -void dm_udev_set_sync_support(int sync_with_udev) +static void _check_udev_sync_requirements_once() { + if (_semaphore_supported < 0) + _semaphore_supported = _check_semaphore_is_supported(); + if (_udev_running < 0) _udev_running = _check_udev_is_running(); +} +void dm_udev_set_sync_support(int sync_with_udev) +{ + _check_udev_sync_requirements_once(); _sync_with_udev = sync_with_udev; } int dm_udev_get_sync_support(void) { - if (_udev_running < 0) - _udev_running = _check_udev_is_running(); + _check_udev_sync_requirements_once(); - return dm_cookie_supported() && _udev_running && _sync_with_udev; + return _semaphore_supported && dm_cookie_supported() && + _udev_running && _sync_with_udev; } void dm_udev_set_checking(int checking)