From ff8adbcfdbbd9c0f2b01ff8a32bc75082fdd9844 Mon Sep 17 00:00:00 2001 From: Tomoki Sekiyama Date: Mon, 13 Jan 2014 12:25:29 -0500 Subject: 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 Reviewed-by: Gal Hammer Reviewed-by: Yan Vugenfirer Signed-off-by: Michael Roth --- qga/vss-win32/requester.cpp | 52 ++++++++++++++++++++++----------------------- 1 file changed, 26 insertions(+), 26 deletions(-) (limited to 'qga/vss-win32/requester.cpp') diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp index 0a55447e81..922e74ddfc 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 -- cgit v1.2.3