diff mbox series

[v5,4/4] QGA VSS: Add log in functions begin/end

Message ID 20230710091439.1010553-5-kkostiuk@redhat.com (mailing list archive)
State New, archived
Headers show
Series QGA VSS Logging | expand

Commit Message

Konstantin Kostiuk July 10, 2023, 9:14 a.m. UTC 
Add several qga_debug() statements in functions.

Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>
---
 qga/vss-win32/install.cpp   | 35 +++++++++++++++++++++++++++++++++++
 qga/vss-win32/provider.cpp  |  3 +++
 qga/vss-win32/requester.cpp | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 72 insertions(+)

Comments

Konstantin Kostiuk July 10, 2023, 10:38 a.m. UTC | #1 
Hi Thomas,

Do you have any other comments about this commit?

On Mon, Jul 10, 2023 at 12:16 PM Konstantin Kostiuk <kkostiuk@redhat.com>
wrote:

> Add several qga_debug() statements in functions.
>
> Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>
> ---
>  qga/vss-win32/install.cpp   | 35 +++++++++++++++++++++++++++++++++++
>  qga/vss-win32/provider.cpp  |  3 +++
>  qga/vss-win32/requester.cpp | 34 ++++++++++++++++++++++++++++++++++
>  3 files changed, 72 insertions(+)
>
> diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
> index e03473d1a8..ae38662a62 100644
> --- a/qga/vss-win32/install.cpp
> +++ b/qga/vss-win32/install.cpp
> @@ -100,6 +100,8 @@ HRESULT put_Value(ICatalogObject *pObj, LPCWSTR name,
> T val)
>  /* Lookup Administrators group name from winmgmt */
>  static HRESULT GetAdminName(_bstr_t *name)
>  {
> +    qga_debug_begin;
> +
>      HRESULT hr;
>      COMPointer<IWbemLocator> pLoc;
>      COMPointer<IWbemServices> pSvc;
> @@ -142,6 +144,7 @@ static HRESULT GetAdminName(_bstr_t *name)
>      }
>
>  out:
> +    qga_debug_end;
>      return hr;
>  }
>
> @@ -149,6 +152,8 @@ out:
>  static HRESULT getNameByStringSID(
>      const wchar_t *sid, LPWSTR buffer, LPDWORD bufferLen)
>  {
> +    qga_debug_begin;
> +
>      HRESULT hr = S_OK;
>      PSID psid = NULL;
>      SID_NAME_USE groupType;
> @@ -168,6 +173,7 @@ static HRESULT getNameByStringSID(
>      LocalFree(psid);
>
>  out:
> +    qga_debug_end;
>      return hr;
>  }
>
> @@ -175,6 +181,8 @@ out:
>  static HRESULT QGAProviderFind(
>      HRESULT (*found)(ICatalogCollection *, int, void *), void *arg)
>  {
> +    qga_debug_begin;
> +
>      HRESULT hr;
>      COMInitializer initializer;
>      COMPointer<IUnknown> pUnknown;
> @@ -205,41 +213,53 @@ static HRESULT QGAProviderFind(
>      chk(pColl->SaveChanges(&n));
>
>  out:
> +    qga_debug_end;
>      return hr;
>  }
>
>  /* Count QGA VSS provider in COM+ Application Catalog */
>  static HRESULT QGAProviderCount(ICatalogCollection *coll, int i, void
> *arg)
>  {
> +    qga_debug_begin;
> +
>      (*(int *)arg)++;
> +
> +    qga_debug_end;
>      return S_OK;
>  }
>
>  /* Remove QGA VSS provider from COM+ Application Catalog Collection */
>  static HRESULT QGAProviderRemove(ICatalogCollection *coll, int i, void
> *arg)
>  {
> +    qga_debug_begin;
>      HRESULT hr;
>
>      qga_debug("Removing COM+ Application: %s", QGA_PROVIDER_NAME);
>      chk(coll->Remove(i));
>  out:
> +    qga_debug_end;
>      return hr;
>  }
>
>  /* Unregister this module from COM+ Applications Catalog */
>  STDAPI COMUnregister(void)
>  {
> +    qga_debug_begin;
> +
>      HRESULT hr;
>
>      DllUnregisterServer();
>      chk(QGAProviderFind(QGAProviderRemove, NULL));
>  out:
> +    qga_debug_end;
>      return hr;
>  }
>
>  /* Register this module to COM+ Applications Catalog */
>  STDAPI COMRegister(void)
>  {
> +    qga_debug_begin;
> +
>      HRESULT hr;
>      COMInitializer initializer;
>      COMPointer<IUnknown> pUnknown;
> @@ -259,12 +279,14 @@ STDAPI COMRegister(void)
>
>      if (!g_hinstDll) {
>          errmsg(E_FAIL, "Failed to initialize DLL");
> +        qga_debug_end;
>          return E_FAIL;
>      }
>
>      chk(QGAProviderFind(QGAProviderCount, (void *)&count));
>      if (count) {
>          errmsg(E_ABORT, "QGA VSS Provider is already installed");
> +        qga_debug_end;
>          return E_ABORT;
>      }
>
> @@ -354,6 +376,7 @@ out:
>          COMUnregister();
>      }
>
> +    qga_debug_end;
>      return hr;
>  }
>
> @@ -369,6 +392,8 @@ STDAPI_(void) CALLBACK DLLCOMUnregister(HWND,
> HINSTANCE, LPSTR, int)
>
>  static BOOL CreateRegistryKey(LPCTSTR key, LPCTSTR value, LPCTSTR data)
>  {
> +    qga_debug_begin;
> +
>      HKEY  hKey;
>      LONG  ret;
>      DWORD size;
> @@ -389,6 +414,7 @@ static BOOL CreateRegistryKey(LPCTSTR key, LPCTSTR
> value, LPCTSTR data)
>      RegCloseKey(hKey);
>
>  out:
> +    qga_debug_end;
>      if (ret != ERROR_SUCCESS) {
>          /* As we cannot printf within DllRegisterServer(), show a dialog.
> */
>          errmsg_dialog(ret, "Cannot add registry", key);
> @@ -400,6 +426,8 @@ out:
>  /* Register this dll as a VSS provider */
>  STDAPI DllRegisterServer(void)
>  {
> +    qga_debug_begin;
> +
>      COMInitializer initializer;
>      COMPointer<IVssAdmin> pVssAdmin;
>      HRESULT hr = E_FAIL;
> @@ -478,12 +506,15 @@ out:
>          DllUnregisterServer();
>      }
>
> +    qga_debug_end;
>      return hr;
>  }
>
>  /* Unregister this VSS hardware provider from the system */
>  STDAPI DllUnregisterServer(void)
>  {
> +    qga_debug_begin;
> +
>      TCHAR key[256];
>      COMInitializer initializer;
>      COMPointer<IVssAdmin> pVssAdmin;
> @@ -501,6 +532,7 @@ STDAPI DllUnregisterServer(void)
>      SHDeleteKey(HKEY_CLASSES_ROOT, key);
>      SHDeleteKey(HKEY_CLASSES_ROOT, g_szProgid);
>
> +    qga_debug_end;
>      return S_OK; /* Uninstall should never fail */
>  }
>
> @@ -527,6 +559,8 @@ namespace _com_util
>  /* Stop QGA VSS provider service using Winsvc API  */
>  STDAPI StopService(void)
>  {
> +    qga_debug_begin;
> +
>      HRESULT hr = S_OK;
>      SC_HANDLE manager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
>      SC_HANDLE service = NULL;
> @@ -551,5 +585,6 @@ STDAPI StopService(void)
>  out:
>      CloseServiceHandle(service);
>      CloseServiceHandle(manager);
> +    qga_debug_end;
>      return hr;
>  }
> diff --git a/qga/vss-win32/provider.cpp b/qga/vss-win32/provider.cpp
> index 1b885e24ee..cc72e5ef1b 100644
> --- a/qga/vss-win32/provider.cpp
> +++ b/qga/vss-win32/provider.cpp
> @@ -12,6 +12,7 @@
>
>  #include "qemu/osdep.h"
>  #include "vss-common.h"
> +#include "vss-debug.h"
>  #ifdef HAVE_VSS_SDK
>  #include <vscoordint.h>
>  #else
> @@ -529,9 +530,11 @@ STDAPI DllCanUnloadNow()
>  EXTERN_C
>  BOOL WINAPI DllMain(HINSTANCE hinstDll, DWORD dwReason, LPVOID lpReserved)
>  {
> +    qga_debug("begin, reason = %lu", dwReason);
>      if (dwReason == DLL_PROCESS_ATTACH) {
>          g_hinstDll = hinstDll;
>          DisableThreadLibraryCalls(hinstDll);
>      }
> +    qga_debug_end;
>      return TRUE;
>  }
> diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp
> index f3eafacfc1..9884c65e70 100644
> --- a/qga/vss-win32/requester.cpp
> +++ b/qga/vss-win32/requester.cpp
> @@ -57,6 +57,8 @@ static struct QGAVSSContext {
>
>  STDAPI requester_init(void)
>  {
> +    qga_debug_begin;
> +
>      COMInitializer initializer; /* to call CoInitializeSecurity */
>      HRESULT hr = CoInitializeSecurity(
>          NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_PKT_PRIVACY,
> @@ -92,11 +94,14 @@ STDAPI requester_init(void)
>          return HRESULT_FROM_WIN32(GetLastError());
>      }
>
> +    qga_debug_end;
>      return S_OK;
>  }
>
>  static void requester_cleanup(void)
>  {
> +    qga_debug_begin;
> +
>      if (vss_ctx.hEventFrozen) {
>          CloseHandle(vss_ctx.hEventFrozen);
>          vss_ctx.hEventFrozen = NULL;
> @@ -118,10 +123,13 @@ static void requester_cleanup(void)
>          vss_ctx.pVssbc = NULL;
>      }
>      vss_ctx.cFrozenVols = 0;
> +    qga_debug_end;
>  }
>
>  STDAPI requester_deinit(void)
>  {
> +    qga_debug_begin;
> +
>      requester_cleanup();
>
>      pCreateVssBackupComponents = NULL;
> @@ -131,11 +139,14 @@ STDAPI requester_deinit(void)
>          hLib = NULL;
>      }
>
> +    qga_debug_end;
>      return S_OK;
>  }
>
>  static HRESULT WaitForAsync(IVssAsync *pAsync)
>  {
> +    qga_debug_begin;
> +
>      HRESULT ret, hr;
>
>      do {
> @@ -151,11 +162,14 @@ static HRESULT WaitForAsync(IVssAsync *pAsync)
>          }
>      } while (ret == VSS_S_ASYNC_PENDING);
>
> +    qga_debug_end;
>      return ret;
>  }
>
>  static void AddComponents(ErrorSet *errset)
>  {
> +    qga_debug_begin;
> +
>      unsigned int cWriters, i;
>      VSS_ID id, idInstance, idWriter;
>      BSTR bstrWriterName = NULL;
> @@ -237,17 +251,21 @@ out:
>      if (pComponent && info) {
>          pComponent->FreeComponentInfo(info);
>      }
> +    qga_debug_end;
>  }
>
>  DWORD get_reg_dword_value(HKEY baseKey, LPCSTR subKey, LPCSTR valueName,
>                            DWORD defaultData)
>  {
> +    qga_debug_begin;
> +
>      DWORD regGetValueError;
>      DWORD dwordData;
>      DWORD dataSize = sizeof(DWORD);
>
>      regGetValueError = RegGetValue(baseKey, subKey, valueName,
> RRF_RT_DWORD,
>                                     NULL, &dwordData, &dataSize);
> +    qga_debug_end;
>      if (regGetValueError  != ERROR_SUCCESS) {
>          return defaultData;
>      }
> @@ -262,6 +280,8 @@ bool is_valid_vss_backup_type(VSS_BACKUP_TYPE vssBT)
>  VSS_BACKUP_TYPE get_vss_backup_type(
>      VSS_BACKUP_TYPE defaultVssBT = DEFAULT_VSS_BACKUP_TYPE)
>  {
> +    qga_debug_begin;
> +
>      VSS_BACKUP_TYPE vssBackupType;
>
>      vssBackupType = static_cast<VSS_BACKUP_TYPE>(
> @@ -269,6 +289,7 @@ VSS_BACKUP_TYPE get_vss_backup_type(
>
>  QGA_PROVIDER_REGISTRY_ADDRESS,
>                                                  "VssOption",
>                                                  defaultVssBT));
> +    qga_debug_end;
>      if (!is_valid_vss_backup_type(vssBackupType)) {
>          return defaultVssBT;
>      }
> @@ -277,6 +298,8 @@ VSS_BACKUP_TYPE get_vss_backup_type(
>
>  void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset)
>  {
> +    qga_debug_begin;
> +
>      COMPointer<IVssAsync> pAsync;
>      HANDLE volume;
>      HRESULT hr;
> @@ -292,6 +315,7 @@ void requester_freeze(int *num_vols, void
> *mountpoints, ErrorSet *errset)
>
>      if (vss_ctx.pVssbc) { /* already frozen */
>          *num_vols = 0;
> +        qga_debug("finished, already frozen");
>          return;
>      }
>
> @@ -449,6 +473,7 @@ void requester_freeze(int *num_vols, void
> *mountpoints, ErrorSet *errset)
>          }
>      }
>
> +    qga_debug("preparing for backup");
>      hr = vss_ctx.pVssbc->PrepareForBackup(pAsync.replace());
>      if (SUCCEEDED(hr)) {
>          hr = WaitForAsync(pAsync);
> @@ -472,6 +497,7 @@ void requester_freeze(int *num_vols, void
> *mountpoints, ErrorSet *errset)
>       * CQGAVssProvider::CommitSnapshots will kick vss_ctx.hEventFrozen
>       * after the applications and filesystems are frozen.
>       */
> +    qga_debug("do snapshot set");
>      hr = vss_ctx.pVssbc->DoSnapshotSet(&vss_ctx.pAsyncSnapshot);
>      if (FAILED(hr)) {
>          err_set(errset, hr, "failed to do snapshot set");
> @@ -518,6 +544,7 @@ void requester_freeze(int *num_vols, void
> *mountpoints, ErrorSet *errset)
>          *num_vols = vss_ctx.cFrozenVols = num_fixed_drives;
>      }
>
> +    qga_debug("end successful");
>      return;
>
>  out:
> @@ -528,11 +555,14 @@ out:
>  out1:
>      requester_cleanup();
>      CoUninitialize();
> +
> +    qga_debug_end;
>  }
>
>
>  void requester_thaw(int *num_vols, void *mountpints, ErrorSet *errset)
>  {
> +    qga_debug_begin;
>      COMPointer<IVssAsync> pAsync;
>
>      if (!vss_ctx.hEventThaw) {
> @@ -541,6 +571,8 @@ void requester_thaw(int *num_vols, void *mountpints,
> ErrorSet *errset)
>           * and no volumes must be frozen. We return without an error.
>           */
>          *num_vols = 0;
> +        qga_debug("finished, no volumes were frozen");
> +
>          return;
>      }
>
> @@ -597,4 +629,6 @@ void requester_thaw(int *num_vols, void *mountpints,
> ErrorSet *errset)
>
>      CoUninitialize();
>      StopService();
> +
> +    qga_debug_end;
>  }
> --
> 2.34.1
>
>
>
Thomas Huth July 10, 2023, 10:56 a.m. UTC | #2 
On 10/07/2023 12.38, Konstantin Kostiuk wrote:
> Hi Thomas,
> 
> Do you have any other comments about this commit?

Looks good to me now!

Reviewed-by: Thomas Huth <thuth@redhat.com>
diff mbox series

Patch

diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
index e03473d1a8..ae38662a62 100644
--- a/qga/vss-win32/install.cpp
+++ b/qga/vss-win32/install.cpp
@@ -100,6 +100,8 @@  HRESULT put_Value(ICatalogObject *pObj, LPCWSTR name, T val)
 /* Lookup Administrators group name from winmgmt */
 static HRESULT GetAdminName(_bstr_t *name)
 {
+    qga_debug_begin;
+
     HRESULT hr;
     COMPointer<IWbemLocator> pLoc;
     COMPointer<IWbemServices> pSvc;
@@ -142,6 +144,7 @@  static HRESULT GetAdminName(_bstr_t *name)
     }
 
 out:
+    qga_debug_end;
     return hr;
 }
 
@@ -149,6 +152,8 @@  out:
 static HRESULT getNameByStringSID(
     const wchar_t *sid, LPWSTR buffer, LPDWORD bufferLen)
 {
+    qga_debug_begin;
+
     HRESULT hr = S_OK;
     PSID psid = NULL;
     SID_NAME_USE groupType;
@@ -168,6 +173,7 @@  static HRESULT getNameByStringSID(
     LocalFree(psid);
 
 out:
+    qga_debug_end;
     return hr;
 }
 
@@ -175,6 +181,8 @@  out:
 static HRESULT QGAProviderFind(
     HRESULT (*found)(ICatalogCollection *, int, void *), void *arg)
 {
+    qga_debug_begin;
+
     HRESULT hr;
     COMInitializer initializer;
     COMPointer<IUnknown> pUnknown;
@@ -205,41 +213,53 @@  static HRESULT QGAProviderFind(
     chk(pColl->SaveChanges(&n));
 
 out:
+    qga_debug_end;
     return hr;
 }
 
 /* Count QGA VSS provider in COM+ Application Catalog */
 static HRESULT QGAProviderCount(ICatalogCollection *coll, int i, void *arg)
 {
+    qga_debug_begin;
+
     (*(int *)arg)++;
+
+    qga_debug_end;
     return S_OK;
 }
 
 /* Remove QGA VSS provider from COM+ Application Catalog Collection */
 static HRESULT QGAProviderRemove(ICatalogCollection *coll, int i, void *arg)
 {
+    qga_debug_begin;
     HRESULT hr;
 
     qga_debug("Removing COM+ Application: %s", QGA_PROVIDER_NAME);
     chk(coll->Remove(i));
 out:
+    qga_debug_end;
     return hr;
 }
 
 /* Unregister this module from COM+ Applications Catalog */
 STDAPI COMUnregister(void)
 {
+    qga_debug_begin;
+
     HRESULT hr;
 
     DllUnregisterServer();
     chk(QGAProviderFind(QGAProviderRemove, NULL));
 out:
+    qga_debug_end;
     return hr;
 }
 
 /* Register this module to COM+ Applications Catalog */
 STDAPI COMRegister(void)
 {
+    qga_debug_begin;
+
     HRESULT hr;
     COMInitializer initializer;
     COMPointer<IUnknown> pUnknown;
@@ -259,12 +279,14 @@  STDAPI COMRegister(void)
 
     if (!g_hinstDll) {
         errmsg(E_FAIL, "Failed to initialize DLL");
+        qga_debug_end;
         return E_FAIL;
     }
 
     chk(QGAProviderFind(QGAProviderCount, (void *)&count));
     if (count) {
         errmsg(E_ABORT, "QGA VSS Provider is already installed");
+        qga_debug_end;
         return E_ABORT;
     }
 
@@ -354,6 +376,7 @@  out:
         COMUnregister();
     }
 
+    qga_debug_end;
     return hr;
 }
 
@@ -369,6 +392,8 @@  STDAPI_(void) CALLBACK DLLCOMUnregister(HWND, HINSTANCE, LPSTR, int)
 
 static BOOL CreateRegistryKey(LPCTSTR key, LPCTSTR value, LPCTSTR data)
 {
+    qga_debug_begin;
+
     HKEY  hKey;
     LONG  ret;
     DWORD size;
@@ -389,6 +414,7 @@  static BOOL CreateRegistryKey(LPCTSTR key, LPCTSTR value, LPCTSTR data)
     RegCloseKey(hKey);
 
 out:
+    qga_debug_end;
     if (ret != ERROR_SUCCESS) {
         /* As we cannot printf within DllRegisterServer(), show a dialog. */
         errmsg_dialog(ret, "Cannot add registry", key);
@@ -400,6 +426,8 @@  out:
 /* Register this dll as a VSS provider */
 STDAPI DllRegisterServer(void)
 {
+    qga_debug_begin;
+
     COMInitializer initializer;
     COMPointer<IVssAdmin> pVssAdmin;
     HRESULT hr = E_FAIL;
@@ -478,12 +506,15 @@  out:
         DllUnregisterServer();
     }
 
+    qga_debug_end;
     return hr;
 }
 
 /* Unregister this VSS hardware provider from the system */
 STDAPI DllUnregisterServer(void)
 {
+    qga_debug_begin;
+
     TCHAR key[256];
     COMInitializer initializer;
     COMPointer<IVssAdmin> pVssAdmin;
@@ -501,6 +532,7 @@  STDAPI DllUnregisterServer(void)
     SHDeleteKey(HKEY_CLASSES_ROOT, key);
     SHDeleteKey(HKEY_CLASSES_ROOT, g_szProgid);
 
+    qga_debug_end;
     return S_OK; /* Uninstall should never fail */
 }
 
@@ -527,6 +559,8 @@  namespace _com_util
 /* Stop QGA VSS provider service using Winsvc API  */
 STDAPI StopService(void)
 {
+    qga_debug_begin;
+
     HRESULT hr = S_OK;
     SC_HANDLE manager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
     SC_HANDLE service = NULL;
@@ -551,5 +585,6 @@  STDAPI StopService(void)
 out:
     CloseServiceHandle(service);
     CloseServiceHandle(manager);
+    qga_debug_end;
     return hr;
 }
diff --git a/qga/vss-win32/provider.cpp b/qga/vss-win32/provider.cpp
index 1b885e24ee..cc72e5ef1b 100644
--- a/qga/vss-win32/provider.cpp
+++ b/qga/vss-win32/provider.cpp
@@ -12,6 +12,7 @@ 
 
 #include "qemu/osdep.h"
 #include "vss-common.h"
+#include "vss-debug.h"
 #ifdef HAVE_VSS_SDK
 #include <vscoordint.h>
 #else
@@ -529,9 +530,11 @@  STDAPI DllCanUnloadNow()
 EXTERN_C
 BOOL WINAPI DllMain(HINSTANCE hinstDll, DWORD dwReason, LPVOID lpReserved)
 {
+    qga_debug("begin, reason = %lu", dwReason);
     if (dwReason == DLL_PROCESS_ATTACH) {
         g_hinstDll = hinstDll;
         DisableThreadLibraryCalls(hinstDll);
     }
+    qga_debug_end;
     return TRUE;
 }
diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp
index f3eafacfc1..9884c65e70 100644
--- a/qga/vss-win32/requester.cpp
+++ b/qga/vss-win32/requester.cpp
@@ -57,6 +57,8 @@  static struct QGAVSSContext {
 
 STDAPI requester_init(void)
 {
+    qga_debug_begin;
+
     COMInitializer initializer; /* to call CoInitializeSecurity */
     HRESULT hr = CoInitializeSecurity(
         NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_PKT_PRIVACY,
@@ -92,11 +94,14 @@  STDAPI requester_init(void)
         return HRESULT_FROM_WIN32(GetLastError());
     }
 
+    qga_debug_end;
     return S_OK;
 }
 
 static void requester_cleanup(void)
 {
+    qga_debug_begin;
+
     if (vss_ctx.hEventFrozen) {
         CloseHandle(vss_ctx.hEventFrozen);
         vss_ctx.hEventFrozen = NULL;
@@ -118,10 +123,13 @@  static void requester_cleanup(void)
         vss_ctx.pVssbc = NULL;
     }
     vss_ctx.cFrozenVols = 0;
+    qga_debug_end;
 }
 
 STDAPI requester_deinit(void)
 {
+    qga_debug_begin;
+
     requester_cleanup();
 
     pCreateVssBackupComponents = NULL;
@@ -131,11 +139,14 @@  STDAPI requester_deinit(void)
         hLib = NULL;
     }
 
+    qga_debug_end;
     return S_OK;
 }
 
 static HRESULT WaitForAsync(IVssAsync *pAsync)
 {
+    qga_debug_begin;
+
     HRESULT ret, hr;
 
     do {
@@ -151,11 +162,14 @@  static HRESULT WaitForAsync(IVssAsync *pAsync)
         }
     } while (ret == VSS_S_ASYNC_PENDING);
 
+    qga_debug_end;
     return ret;
 }
 
 static void AddComponents(ErrorSet *errset)
 {
+    qga_debug_begin;
+
     unsigned int cWriters, i;
     VSS_ID id, idInstance, idWriter;
     BSTR bstrWriterName = NULL;
@@ -237,17 +251,21 @@  out:
     if (pComponent && info) {
         pComponent->FreeComponentInfo(info);
     }
+    qga_debug_end;
 }
 
 DWORD get_reg_dword_value(HKEY baseKey, LPCSTR subKey, LPCSTR valueName,
                           DWORD defaultData)
 {
+    qga_debug_begin;
+
     DWORD regGetValueError;
     DWORD dwordData;
     DWORD dataSize = sizeof(DWORD);
 
     regGetValueError = RegGetValue(baseKey, subKey, valueName, RRF_RT_DWORD,
                                    NULL, &dwordData, &dataSize);
+    qga_debug_end;
     if (regGetValueError  != ERROR_SUCCESS) {
         return defaultData;
     }
@@ -262,6 +280,8 @@  bool is_valid_vss_backup_type(VSS_BACKUP_TYPE vssBT)
 VSS_BACKUP_TYPE get_vss_backup_type(
     VSS_BACKUP_TYPE defaultVssBT = DEFAULT_VSS_BACKUP_TYPE)
 {
+    qga_debug_begin;
+
     VSS_BACKUP_TYPE vssBackupType;
 
     vssBackupType = static_cast<VSS_BACKUP_TYPE>(
@@ -269,6 +289,7 @@  VSS_BACKUP_TYPE get_vss_backup_type(
                                                 QGA_PROVIDER_REGISTRY_ADDRESS,
                                                 "VssOption",
                                                 defaultVssBT));
+    qga_debug_end;
     if (!is_valid_vss_backup_type(vssBackupType)) {
         return defaultVssBT;
     }
@@ -277,6 +298,8 @@  VSS_BACKUP_TYPE get_vss_backup_type(
 
 void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset)
 {
+    qga_debug_begin;
+
     COMPointer<IVssAsync> pAsync;
     HANDLE volume;
     HRESULT hr;
@@ -292,6 +315,7 @@  void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset)
 
     if (vss_ctx.pVssbc) { /* already frozen */
         *num_vols = 0;
+        qga_debug("finished, already frozen");
         return;
     }
 
@@ -449,6 +473,7 @@  void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset)
         }
     }
 
+    qga_debug("preparing for backup");
     hr = vss_ctx.pVssbc->PrepareForBackup(pAsync.replace());
     if (SUCCEEDED(hr)) {
         hr = WaitForAsync(pAsync);
@@ -472,6 +497,7 @@  void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset)
      * CQGAVssProvider::CommitSnapshots will kick vss_ctx.hEventFrozen
      * after the applications and filesystems are frozen.
      */
+    qga_debug("do snapshot set");
     hr = vss_ctx.pVssbc->DoSnapshotSet(&vss_ctx.pAsyncSnapshot);
     if (FAILED(hr)) {
         err_set(errset, hr, "failed to do snapshot set");
@@ -518,6 +544,7 @@  void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset)
         *num_vols = vss_ctx.cFrozenVols = num_fixed_drives;
     }
 
+    qga_debug("end successful");
     return;
 
 out:
@@ -528,11 +555,14 @@  out:
 out1:
     requester_cleanup();
     CoUninitialize();
+
+    qga_debug_end;
 }
 
 
 void requester_thaw(int *num_vols, void *mountpints, ErrorSet *errset)
 {
+    qga_debug_begin;
     COMPointer<IVssAsync> pAsync;
 
     if (!vss_ctx.hEventThaw) {
@@ -541,6 +571,8 @@  void requester_thaw(int *num_vols, void *mountpints, ErrorSet *errset)
          * and no volumes must be frozen. We return without an error.
          */
         *num_vols = 0;
+        qga_debug("finished, no volumes were frozen");
+
         return;
     }
 
@@ -597,4 +629,6 @@  void requester_thaw(int *num_vols, void *mountpints, ErrorSet *errset)
 
     CoUninitialize();
     StopService();
+
+    qga_debug_end;
 }