[Qemu-devel] [PULL v2 02/24] qga-win: add support for qmp_guest_fsfreeze_freeze_list

[Michael Roth <mdroth@linux.vnet.ibm.com>]

From: Chen Hanxiao <chenhanxiao@gmail.com>

This patch add support for freeze specified fs.

The valid mountpoints list member are [1]:

  The path of a mounted folder, for example, Y:\MountX\
  A drive letter, for example, D:\
  A volume GUID path of the form \\?\Volume{GUID}\,
      where GUID identifies the volume
  A UNC path that specifies a remote file share,
      for example, \\Clusterx\Share1\

[1] https://docs.microsoft.com/en-us/windows/desktop/api/vsbackup/nf-vsbackup-ivssbackupcomponents-addtosnapshotset

Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 qga/commands-win32.c        | 21 ++++-----
 qga/main.c                  |  2 +-
 qga/vss-win32.c             |  5 +-
 qga/vss-win32.h             |  3 +-
 qga/vss-win32/requester.cpp | 92 ++++++++++++++++++++++++++-----------
 qga/vss-win32/requester.h   | 13 ++++--
 6 files changed, 91 insertions(+), 45 deletions(-)

diff --git a/qga/commands-win32.c b/qga/commands-win32.c
index 416343b97b..347577f2a4 100644
--- a/qga/commands-win32.c
+++ b/qga/commands-win32.c
@@ -790,6 +790,13 @@ GuestFsfreezeStatus qmp_guest_fsfreeze_status(Error **errp)
  * The frozen state is limited for up to 10 seconds by VSS.
  */
 int64_t qmp_guest_fsfreeze_freeze(Error **errp)
+{
+    return qmp_guest_fsfreeze_freeze_list(false, NULL, errp);
+}
+
+int64_t qmp_guest_fsfreeze_freeze_list(bool has_mountpoints,
+                                       strList *mountpoints,
+                                       Error **errp)
 {
     int i;
     Error *local_err = NULL;
@@ -804,7 +811,7 @@ int64_t qmp_guest_fsfreeze_freeze(Error **errp)
     /* cannot risk guest agent blocking itself on a write in this state */
     ga_set_frozen(ga_state);
 
-    qga_vss_fsfreeze(&i, true, &local_err);
+    qga_vss_fsfreeze(&i, true, mountpoints, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         goto error;
@@ -822,15 +829,6 @@ error:
     return 0;
 }
 
-int64_t qmp_guest_fsfreeze_freeze_list(bool has_mountpoints,
-                                       strList *mountpoints,
-                                       Error **errp)
-{
-    error_setg(errp, QERR_UNSUPPORTED);
-
-    return 0;
-}
-
 /*
  * Thaw local file systems using Volume Shadow-copy Service.
  */
@@ -843,7 +841,7 @@ int64_t qmp_guest_fsfreeze_thaw(Error **errp)
         return 0;
     }
 
-    qga_vss_fsfreeze(&i, false, errp);
+    qga_vss_fsfreeze(&i, false, NULL, errp);
 
     ga_unset_frozen(ga_state);
     return i;
@@ -1660,7 +1658,6 @@ GList *ga_command_blacklist_init(GList *blacklist)
         "guest-set-vcpus",
         "guest-get-memory-blocks", "guest-set-memory-blocks",
         "guest-get-memory-block-size",
-        "guest-fsfreeze-freeze-list",
         NULL};
     char **p = (char **)list_unsupported;
 
diff --git a/qga/main.c b/qga/main.c
index c399320d3c..afcd268ee3 100644
--- a/qga/main.c
+++ b/qga/main.c
@@ -151,7 +151,7 @@ static void quit_handler(int sig)
             WaitForSingleObject(hEventTimeout, 0);
             CloseHandle(hEventTimeout);
         }
-        qga_vss_fsfreeze(&i, false, &err);
+        qga_vss_fsfreeze(&i, false, NULL, &err);
         if (err) {
             g_debug("Error unfreezing filesystems prior to exiting: %s",
                 error_get_pretty(err));
diff --git a/qga/vss-win32.c b/qga/vss-win32.c
index a541f3ae01..f444a25a70 100644
--- a/qga/vss-win32.c
+++ b/qga/vss-win32.c
@@ -147,7 +147,8 @@ void ga_uninstall_vss_provider(void)
 }
 
 /* Call VSS requester and freeze/thaw filesystems and applications */
-void qga_vss_fsfreeze(int *nr_volume, bool freeze, Error **errp)
+void qga_vss_fsfreeze(int *nr_volume, bool freeze,
+                      strList *mountpoints, Error **errp)
 {
     const char *func_name = freeze ? "requester_freeze" : "requester_thaw";
     QGAVSSRequesterFunc func;
@@ -164,5 +165,5 @@ void qga_vss_fsfreeze(int *nr_volume, bool freeze, Error **errp)
         return;
     }
 
-    func(nr_volume, &errset);
+    func(nr_volume, mountpoints, &errset);
 }
diff --git a/qga/vss-win32.h b/qga/vss-win32.h
index 4f8e39aa5c..ce2abe5a72 100644
--- a/qga/vss-win32.h
+++ b/qga/vss-win32.h
@@ -22,6 +22,7 @@ bool vss_initialized(void);
 int ga_install_vss_provider(void);
 void ga_uninstall_vss_provider(void);
 
-void qga_vss_fsfreeze(int *nr_volume, bool freeze, Error **errp);
+void qga_vss_fsfreeze(int *nr_volume, bool freeze,
+                      strList *mountpints, Error **errp);
 
 #endif
diff --git a/qga/vss-win32/requester.cpp b/qga/vss-win32/requester.cpp
index 3d9c9716c0..5378c55d23 100644
--- a/qga/vss-win32/requester.cpp
+++ b/qga/vss-win32/requester.cpp
@@ -234,7 +234,7 @@ out:
     }
 }
 
-void requester_freeze(int *num_vols, ErrorSet *errset)
+void requester_freeze(int *num_vols, void *mountpoints, ErrorSet *errset)
 {
     COMPointer<IVssAsync> pAsync;
     HANDLE volume;
@@ -246,6 +246,7 @@ void requester_freeze(int *num_vols, ErrorSet *errset)
     WCHAR short_volume_name[64], *display_name = short_volume_name;
     DWORD wait_status;
     int num_fixed_drives = 0, i;
+    int num_mount_points = 0;
 
     if (vss_ctx.pVssbc) { /* already frozen */
         *num_vols = 0;
@@ -337,39 +338,73 @@ void requester_freeze(int *num_vols, ErrorSet *errset)
         goto out;
     }
 
-    volume = FindFirstVolumeW(short_volume_name, sizeof(short_volume_name));
-    if (volume == INVALID_HANDLE_VALUE) {
-        err_set(errset, hr, "failed to find first volume");
-        goto out;
-    }
-    for (;;) {
-        if (GetDriveTypeW(short_volume_name) == DRIVE_FIXED) {
+    if (mountpoints) {
+        PWCHAR volume_name_wchar;
+        for (volList *list = (volList *)mountpoints; list; list = list->next) {
+            size_t len = strlen(list->value) + 1;
+            size_t converted = 0;
             VSS_ID pid;
-            hr = vss_ctx.pVssbc->AddToSnapshotSet(short_volume_name,
+
+            volume_name_wchar = new wchar_t[len];
+            mbstowcs_s(&converted, volume_name_wchar, len,
+                       list->value, _TRUNCATE);
+
+            hr = vss_ctx.pVssbc->AddToSnapshotSet(volume_name_wchar,
                                                   g_gProviderId, &pid);
             if (FAILED(hr)) {
-                WCHAR volume_path_name[PATH_MAX];
-                if (GetVolumePathNamesForVolumeNameW(
-                        short_volume_name, volume_path_name,
-                        sizeof(volume_path_name), NULL) && *volume_path_name) {
-                    display_name = volume_path_name;
-                }
                 err_set(errset, hr, "failed to add %S to snapshot set",
-                                 display_name);
-                FindVolumeClose(volume);
+                        volume_name_wchar);
+                delete volume_name_wchar;
                 goto out;
             }
-            num_fixed_drives++;
+            num_mount_points++;
+
+            delete volume_name_wchar;
         }
-        if (!FindNextVolumeW(volume, short_volume_name,
-                             sizeof(short_volume_name))) {
-            FindVolumeClose(volume);
-            break;
+
+        if (num_mount_points == 0) {
+            /* If there is no valid mount points, just exit. */
+            goto out;
         }
     }
 
-    if (num_fixed_drives == 0) {
-        goto out; /* If there is no fixed drive, just exit. */
+    if (!mountpoints) {
+        volume = FindFirstVolumeW(short_volume_name, sizeof(short_volume_name));
+        if (volume == INVALID_HANDLE_VALUE) {
+            err_set(errset, hr, "failed to find first volume");
+            goto out;
+        }
+
+        for (;;) {
+            if (GetDriveTypeW(short_volume_name) == DRIVE_FIXED) {
+                VSS_ID pid;
+                hr = vss_ctx.pVssbc->AddToSnapshotSet(short_volume_name,
+                                                      g_gProviderId, &pid);
+                if (FAILED(hr)) {
+                    WCHAR volume_path_name[PATH_MAX];
+                    if (GetVolumePathNamesForVolumeNameW(
+                            short_volume_name, volume_path_name,
+                            sizeof(volume_path_name), NULL) &&
+                            *volume_path_name) {
+                        display_name = volume_path_name;
+                    }
+                    err_set(errset, hr, "failed to add %S to snapshot set",
+                            display_name);
+                    FindVolumeClose(volume);
+                    goto out;
+                }
+                num_fixed_drives++;
+            }
+            if (!FindNextVolumeW(volume, short_volume_name,
+                                 sizeof(short_volume_name))) {
+                FindVolumeClose(volume);
+                break;
+            }
+        }
+
+        if (num_fixed_drives == 0) {
+            goto out; /* If there is no fixed drive, just exit. */
+        }
     }
 
     hr = vss_ctx.pVssbc->PrepareForBackup(pAsync.replace());
@@ -435,7 +470,12 @@ void requester_freeze(int *num_vols, ErrorSet *errset)
         goto out;
     }
 
-    *num_vols = vss_ctx.cFrozenVols = num_fixed_drives;
+    if (mountpoints) {
+        *num_vols = vss_ctx.cFrozenVols = num_mount_points;
+    } else {
+        *num_vols = vss_ctx.cFrozenVols = num_fixed_drives;
+    }
+
     return;
 
 out:
@@ -449,7 +489,7 @@ out1:
 }
 
 
-void requester_thaw(int *num_vols, ErrorSet *errset)
+void requester_thaw(int *num_vols, void *mountpints, ErrorSet *errset)
 {
     COMPointer<IVssAsync> pAsync;
 
diff --git a/qga/vss-win32/requester.h b/qga/vss-win32/requester.h
index 2a39d734a2..5a8e8faf0c 100644
--- a/qga/vss-win32/requester.h
+++ b/qga/vss-win32/requester.h
@@ -34,9 +34,16 @@ typedef struct ErrorSet {
 STDAPI requester_init(void);
 STDAPI requester_deinit(void);
 
-typedef void (*QGAVSSRequesterFunc)(int *, ErrorSet *);
-void requester_freeze(int *num_vols, ErrorSet *errset);
-void requester_thaw(int *num_vols, ErrorSet *errset);
+typedef struct volList volList;
+
+struct volList {
+    volList *next;
+    char *value;
+};
+
+typedef void (*QGAVSSRequesterFunc)(int *, void *, ErrorSet *);
+void requester_freeze(int *num_vols, void *volList, ErrorSet *errset);
+void requester_thaw(int *num_vols, void *volList, ErrorSet *errset);
 
 #ifdef __cplusplus
 }
-- 
2.17.1