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authorTomoki Sekiyama <tomoki.sekiyama@hds.com>2014-01-13 12:25:29 -0500
committerMichael Roth <mdroth@linux.vnet.ibm.com>2014-02-23 13:11:26 -0600
commitff8adbcfdbbd9c0f2b01ff8a32bc75082fdd9844 (patch)
tree5471f51bee348167b44832e72b41513f9623fde4 /qga/vss-win32/requester.cpp
parent4c1b8f1e8357d85c613d779596e4079cc581d74f (diff)
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qga: vss-win32: Fix interference with snapshot creation by other VSS requesters
When a VSS requester such as vshadow.exe or diskshadow.exe requests to create disk snapshots, Windows may choose qemu-ga VSS provider if it is only provider registered on the system. However, because it provides only a function to freeze the filesystem, the snapshotting fails. This patch adds a check into CQGAVssProvider::IsVolumeSupported() to reject the request from other VSS requesters, so that the other provider is chosen. The check of requester is done by confirming event channels between qemu-ga's requester and provider established. To ensure that the events are initialized when CQGAVssProvider::IsVolumeSupported() is called, it moves the initialization earlier. Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com> Reviewed-by: Gal Hammer <ghammer@redhat.com> Reviewed-by: Yan Vugenfirer <yvugenfi@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Diffstat (limited to 'qga/vss-win32/requester.cpp')
-rw-r--r--qga/vss-win32/requester.cpp52
1 files changed, 26 insertions, 26 deletions
diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp
index 0a55447..922e74d 100644
--- a/qga/vss-win32/requester.cpp
+++ b/qga/vss-win32/requester.cpp
@@ -252,6 +252,32 @@ void requester_freeze(int *num_vols, ErrorSet *errset)
CoInitialize(NULL);
+ /* Allow unrestricted access to events */
+ InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION);
+ SetSecurityDescriptorDacl(&sd, TRUE, NULL, FALSE);
+ sa.nLength = sizeof(sa);
+ sa.lpSecurityDescriptor = &sd;
+ sa.bInheritHandle = FALSE;
+
+ vss_ctx.hEventFrozen = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_FROZEN);
+ if (!vss_ctx.hEventFrozen) {
+ err_set(errset, GetLastError(), "failed to create event %s",
+ EVENT_NAME_FROZEN);
+ goto out;
+ }
+ vss_ctx.hEventThaw = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_THAW);
+ if (!vss_ctx.hEventThaw) {
+ err_set(errset, GetLastError(), "failed to create event %s",
+ EVENT_NAME_THAW);
+ goto out;
+ }
+ vss_ctx.hEventTimeout = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_TIMEOUT);
+ if (!vss_ctx.hEventTimeout) {
+ err_set(errset, GetLastError(), "failed to create event %s",
+ EVENT_NAME_TIMEOUT);
+ goto out;
+ }
+
assert(pCreateVssBackupComponents != NULL);
hr = pCreateVssBackupComponents(&vss_ctx.pVssbc);
if (FAILED(hr)) {
@@ -362,32 +388,6 @@ void requester_freeze(int *num_vols, ErrorSet *errset)
goto out;
}
- /* Allow unrestricted access to events */
- InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION);
- SetSecurityDescriptorDacl(&sd, TRUE, NULL, FALSE);
- sa.nLength = sizeof(sa);
- sa.lpSecurityDescriptor = &sd;
- sa.bInheritHandle = FALSE;
-
- vss_ctx.hEventFrozen = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_FROZEN);
- if (!vss_ctx.hEventFrozen) {
- err_set(errset, GetLastError(), "failed to create event %s",
- EVENT_NAME_FROZEN);
- goto out;
- }
- vss_ctx.hEventThaw = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_THAW);
- if (!vss_ctx.hEventThaw) {
- err_set(errset, GetLastError(), "failed to create event %s",
- EVENT_NAME_THAW);
- goto out;
- }
- vss_ctx.hEventTimeout = CreateEvent(&sa, TRUE, FALSE, EVENT_NAME_TIMEOUT);
- if (!vss_ctx.hEventTimeout) {
- err_set(errset, GetLastError(), "failed to create event %s",
- EVENT_NAME_TIMEOUT);
- goto out;
- }
-
/*
* Start VSS quiescing operations.
* CQGAVssProvider::CommitSnapshots will kick vss_ctx.hEventFrozen