Patchwork [06/11] savevm: update error reporting for qemu_loadvm_state()

login
register
mail settings
Submitter Pavel Hrdina
Date April 16, 2013, 4:05 p.m.
Message ID <36cf3cc0fded13e1fe2a55561b57de523de89000.1366127809.git.phrdina@redhat.com>
Download mbox | patch
Permalink /patch/237025/
State New
Headers show

Comments

Pavel Hrdina - April 16, 2013, 4:05 p.m.
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 include/sysemu/sysemu.h |  2 +-
 migration.c             |  9 +++----
 savevm.c                | 64 ++++++++++++++++++++++++-------------------------
 3 files changed, 37 insertions(+), 38 deletions(-)
Eric Blake - April 16, 2013, 9:42 p.m.
On 04/16/2013 10:05 AM, Pavel Hrdina wrote:
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  include/sysemu/sysemu.h |  2 +-
>  migration.c             |  9 +++----
>  savevm.c                | 64 ++++++++++++++++++++++++-------------------------
>  3 files changed, 37 insertions(+), 38 deletions(-)
> 

> +++ b/migration.c
> @@ -93,12 +93,13 @@ void qemu_start_incoming_migration(const char *uri, Error **errp)
>  static void process_incoming_migration_co(void *opaque)
>  {
>      QEMUFile *f = opaque;
> -    int ret;
> +    Error *local_err = NULL;
>  
> -    ret = qemu_loadvm_state(f);
> +    qemu_loadvm_state(f, &local_err);
>      qemu_fclose(f);
> -    if (ret < 0) {
> -        fprintf(stderr, "load of migration failed\n");
> +    if (error_is_set(&local_err)) {
> +        fprintf(stderr, "%s\n", error_get_pretty(local_err));
> +        error_free(local_err);
>          exit(0);

Pre-existing, but WHY are we exiting with successful status even when
incoming migration failed?  This feels SOOOO wrong.  Exiting non-zero
would at least give management apps like libvirt a reason to inspect the
output for the error message.

>      v = qemu_get_be32(f);
>      if (v == QEMU_VM_FILE_VERSION_COMPAT) {
> -        fprintf(stderr, "SaveVM v2 format is obsolete and don't work anymore\n");
> -        return -ENOTSUP;
> +        error_setg(errp, "saveVM v2 format is obsolete and don't work anymore");

As long as you are touching this, fix the grammar:

s/don't/doesn't/

As my findings were pre-existing problems:

Reviewed-by: Eric Blake <eblake@redhat.com>

Patch

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index f46f9d2..70c6927 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -78,7 +78,7 @@  int qemu_savevm_state_iterate(QEMUFile *f);
 void qemu_savevm_state_complete(QEMUFile *f);
 void qemu_savevm_state_cancel(void);
 uint64_t qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size);
-int qemu_loadvm_state(QEMUFile *f);
+void qemu_loadvm_state(QEMUFile *f, Error **errp);
 
 /* SLIRP */
 void do_info_slirp(Monitor *mon);
diff --git a/migration.c b/migration.c
index 3b4b467..fd8c869 100644
--- a/migration.c
+++ b/migration.c
@@ -93,12 +93,13 @@  void qemu_start_incoming_migration(const char *uri, Error **errp)
 static void process_incoming_migration_co(void *opaque)
 {
     QEMUFile *f = opaque;
-    int ret;
+    Error *local_err = NULL;
 
-    ret = qemu_loadvm_state(f);
+    qemu_loadvm_state(f, &local_err);
     qemu_fclose(f);
-    if (ret < 0) {
-        fprintf(stderr, "load of migration failed\n");
+    if (error_is_set(&local_err)) {
+        fprintf(stderr, "%s\n", error_get_pretty(local_err));
+        error_free(local_err);
         exit(0);
     }
     qemu_announce_self();
diff --git a/savevm.c b/savevm.c
index ca4a42e..0419e0d 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2077,7 +2077,7 @@  typedef struct LoadStateEntry {
     int version_id;
 } LoadStateEntry;
 
-int qemu_loadvm_state(QEMUFile *f)
+void qemu_loadvm_state(QEMUFile *f, Error **errp)
 {
     QLIST_HEAD(, LoadStateEntry) loadvm_handlers =
         QLIST_HEAD_INITIALIZER(loadvm_handlers);
@@ -2086,21 +2086,25 @@  int qemu_loadvm_state(QEMUFile *f)
     unsigned int v;
     int ret;
 
-    if (qemu_savevm_state_blocked(NULL)) {
-        return -EINVAL;
+    if (qemu_savevm_state_blocked(errp)) {
+        return;
     }
 
     v = qemu_get_be32(f);
-    if (v != QEMU_VM_FILE_MAGIC)
-        return -EINVAL;
+    if (v != QEMU_VM_FILE_MAGIC) {
+        error_setg(errp, "unknown vmstate file magic");
+        return;
+    }
 
     v = qemu_get_be32(f);
     if (v == QEMU_VM_FILE_VERSION_COMPAT) {
-        fprintf(stderr, "SaveVM v2 format is obsolete and don't work anymore\n");
-        return -ENOTSUP;
+        error_setg(errp, "saveVM v2 format is obsolete and don't work anymore");
+        return;
+    }
+    if (v != QEMU_VM_FILE_VERSION) {
+        error_setg(errp, "unknown vmstate file version");
+        return;
     }
-    if (v != QEMU_VM_FILE_VERSION)
-        return -ENOTSUP;
 
     while ((section_type = qemu_get_byte(f)) != QEMU_VM_EOF) {
         uint32_t instance_id, version_id, section_id;
@@ -2122,16 +2126,15 @@  int qemu_loadvm_state(QEMUFile *f)
             /* Find savevm section */
             se = find_se(idstr, instance_id);
             if (se == NULL) {
-                fprintf(stderr, "Unknown savevm section or instance '%s' %d\n", idstr, instance_id);
-                ret = -EINVAL;
+                error_setg(errp, "unknown savevm section or instance '%s' %d",
+                           idstr, instance_id);
                 goto out;
             }
 
             /* Validate version */
             if (version_id > se->version_id) {
-                fprintf(stderr, "savevm: unsupported version %d for '%s' v%d\n",
-                        version_id, idstr, se->version_id);
-                ret = -EINVAL;
+                error_setg(errp, "unsupported version %d for '%s' v%d",
+                           version_id, idstr, se->version_id);
                 goto out;
             }
 
@@ -2145,8 +2148,8 @@  int qemu_loadvm_state(QEMUFile *f)
 
             ret = vmstate_load(f, le->se, le->version_id);
             if (ret < 0) {
-                fprintf(stderr, "qemu: warning: error while loading state for instance 0x%x of device '%s'\n",
-                        instance_id, idstr);
+                error_setg(errp, "error while loading state for instance "
+                           "0x%x of device '%s'", instance_id, idstr);
                 goto out;
             }
             break;
@@ -2160,40 +2163,35 @@  int qemu_loadvm_state(QEMUFile *f)
                 }
             }
             if (le == NULL) {
-                fprintf(stderr, "Unknown savevm section %d\n", section_id);
-                ret = -EINVAL;
+                error_setg(errp, "unknown savevm section %d", section_id);
                 goto out;
             }
 
             ret = vmstate_load(f, le->se, le->version_id);
             if (ret < 0) {
-                fprintf(stderr, "qemu: warning: error while loading state section id %d\n",
+                error_setg(errp, "error while loading state section id %d",
                         section_id);
                 goto out;
             }
             break;
         default:
-            fprintf(stderr, "Unknown savevm section type %d\n", section_type);
-            ret = -EINVAL;
+            error_setg(errp, "unknown savevm section type %d", section_type);
             goto out;
         }
     }
 
     cpu_synchronize_all_post_init();
 
-    ret = 0;
+    ret = qemu_file_get_error(f);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "failed to load vmstate");
+    }
 
 out:
     QLIST_FOREACH_SAFE(le, &loadvm_handlers, entry, new_le) {
         QLIST_REMOVE(le, entry);
         g_free(le);
     }
-
-    if (ret == 0) {
-        ret = qemu_file_get_error(f);
-    }
-
-    return ret;
 }
 
 static int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
@@ -2400,7 +2398,6 @@  int load_vmstate(const char *name)
     BlockDriverState *bs, *bs_vm_state;
     QEMUSnapshotInfo sn;
     QEMUFile *f;
-    int ret;
     Error *local_err;
 
     bs_vm_state = bdrv_snapshots();
@@ -2463,12 +2460,13 @@  int load_vmstate(const char *name)
     }
 
     qemu_system_reset(VMRESET_SILENT);
-    ret = qemu_loadvm_state(f);
+    qemu_loadvm_state(f, &local_err);
 
     qemu_fclose(f);
-    if (ret < 0) {
-        error_report("Error %d while loading VM state", ret);
-        return ret;
+    if (error_is_set(&local_err)) {
+        error_report("%s", error_get_pretty(local_err));
+        error_free(local_err);
+        return -1;
     }
 
     return 0;