Re: [Libvirt-cim] [PATCH] Workaround to fix race condition around libvirt init

Wayne Xia <xiawenc(a)linux.vnet.ibm.com&gt; 08/29/11 02:47 AM To libvirt-cim(a)redhat.com, Sharad Mishra/Beaverton/IBM@IBMUS cc Subject Re: [Libvirt-cim] [PATCH] Workaround to fix race condition around libvirt

Is it possible that libvirt would invoke one VM twice?

also some comments below. 于 2011-8-27 1:32, Sharad Mishra 写道: > # HG changeset patch > # User Sharad Mishra&lt;snmishra(a)us.ibm.com&gt; > # Date 1314379933 25200 > # Node ID a42b68361ed9cb4f7d6f15de5b58ccc68e88ef38 > # Parent a346baf140d64177a9dc1066677c307ee6518236 > Workaround to fix race condition around libvirt init. > > This patch fixes the race condition caused when mutiple > threads try to start a VM. This patch also fixes the issue > of incorrect mem allocation for VSSD property - emulator. > > Signed-off-by: Sharad Mishra&lt;snmishra(a)us.ibm.com&gt; > > diff --git a/libxkutil/misc_util.c b/libxkutil/misc_util.c > --- a/libxkutil/misc_util.c > +++ b/libxkutil/misc_util.c > @@ -28,6 +28,7 @@ > #include<stdbool.h> > #include<stdarg.h> > #include<unistd.h> > +#include<pthread.h> > #include<libvirt/libvirt.h> > #include<libvirt/virterror.h> > > @@ -45,6 +46,9 @@ > #include "misc_util.h" > #include "cs_util.h" > > +static pthread_mutex_t libvirt_mutex = PTHREAD_MUTEX_INITIALIZER; > +/* libvirt library not initialized */ > +static int libvirt_initialized = 0; > > #define URI_ENV "HYPURI" > > @@ -114,11 +118,15 @@ > > CU_DEBUG("Connecting to libvirt with uri `%s'", uri); > > + pthread_mutex_lock(&libvirt_mutex); > + > if (is_read_only()) > conn = virConnectOpenReadOnly(uri); > else > conn = virConnectOpen(uri); > > + pthread_mutex_unlock(&libvirt_mutex); > + > if (!conn) { > CU_DEBUG("Unable to connect to `%s'", uri); > return NULL; > @@ -530,7 +538,19 @@ > > bool libvirt_cim_init(void) > { > - return virInitialize() == 0; > + int ret=0; > + > + /* double-check lock pattern used for performance reasons */ > + if (0 == libvirt_initialized) { > + pthread_mutex_lock(&libvirt_mutex); > + if (0 == libvirt_initialized) { > + ret = virInitialize(); > + if (ret == 0) > + libvirt_initialized=1; > + } > + pthread_mutex_unlock(&libvirt_mutex); > + } > + return (ret == 0); > } > > bool check_refs_pfx_match(const CMPIObjectPath *refa, > diff --git a/src/Virt_VirtualSystemManagementService.c b/src/ Virt_VirtualSystemManagementService.c > --- a/src/Virt_VirtualSystemManagementService.c > +++ b/src/Virt_VirtualSystemManagementService.c > @@ -188,6 +188,20 @@ > return 1; > } > > +static bool make_space(struct virt_device **list, int cur, int new) > +{ > + struct virt_device *tmp; > + > + tmp = calloc(cur + new, sizeof(*tmp)); > + if (tmp == NULL) > + return false; > + maybe some lines should be added here like this: if (*list!=NULL) { memcpy(tmp, *list, sizeof(*tmp) * cur); free(*list); *list = tmp; }

> + memcpy(tmp, *list, sizeof(*tmp) * cur); > + *list = tmp; > + > + return true; > +} > + > static bool fv_set_emulator(struct domain *domain, > const char *emu) > { > @@ -198,6 +212,11 @@ > if (emu == NULL) > return true; > > + if (!make_space(&domain->dev_emu, 0, 1)) { > + CU_DEBUG("Failed to alloc disk list"); > + return false; > + } > + > cleanup_virt_device(domain->dev_emu); > > domain->dev_emu->type = CIM_RES_TYPE_EMU; > @@ -1369,20 +1388,6 @@ > return msg; > } > > -static bool make_space(struct virt_device **list, int cur, int new) > -{ > - struct virt_device *tmp; > - > - tmp = calloc(cur + new, sizeof(*tmp)); > - if (tmp == NULL) > - return false; > - > - memcpy(tmp, *list, sizeof(*tmp) * cur); > - *list = tmp; > - > - return true; > -} > - > static char *add_device_nodup(struct virt_device *dev, > struct virt_device *list, > int max, > > _______________________________________________ > Libvirt-cim mailing list > Libvirt-cim(a)redhat.com > https://www.redhat.com/mailman/listinfo/libvirt-cim -- Best Regards Wayne Xia mail:xiawenc@linux.vnet.ibm.com tel:86-010-82450803