[lvm-devel] LVM2 ./WHATS_NEW_DM libdm/libdm-common.c
prajnoha at sourceware.org
prajnoha at sourceware.org
Tue Aug 3 07:56:04 UTC 2010
CVSROOT: /cvs/lvm2
Module name: LVM2
Changes by: prajnoha at 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)
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