[Qemu-devel] [PATCH v3 00/11] convert savevm to use qapi and introduce qmp command

[Qemu-devel] [PATCH v3 00/11] convert savevm to use qapi and introduce qmp command

[Pavel Hrdina]

This patch series convert the savevm command into qapi and introduce QMP
command vm-snapshot-save.
It also rewrite error report for functions used by this command.

The last patch introduce new functionality of savevm that you cannot override
existing snapshot without using 'force' parameter.

If non-blocking behaviour of this command is required and we cannot wait
until live snapshots will be finished, I could improve this basic command
to be non-blocking.

Changes from v2:
    - correct error messages
    - introduce of 'force' option moved to qapi: Convert savevm
    - update of return value for used functions
    - drop of the speed improve because it isn't actually speed improve
    - vm-snapshot-save and savevm now returns snapshot information

Changes from v1:
    - rebase on current master branch
    - improve the speed of savevm
    - name parameter remains optionl for HMP and QMP

Pavel Hrdina (11):
  block: add error parameter to bdrv_snapshot_create() and related
    functions
  block: add error parameter to del_existing_snapshots()
  savevm: add error parameter to qemu_savevm_state_begin()
  savevm: add error parameter to qemu_savevm_state_iterate()
  savevm: add error parameter to qemu_savevm_state_complete()
  savevm: add error parameter to qemu_savevm_state()
  qapi: Convert savevm
  qemu-img: introduce qemu_img_handle_error
  block: update return value from bdrv_snapshot_create
  savevm: update return value from qemu_savevm_state
  savevm: add force parameter to HMP command and return snapshot info

 block.c                   | 24 +++++++-----
 block/qcow2-snapshot.c    | 15 +++++---
 block/qcow2.h             |  4 +-
 block/rbd.c               | 19 +++++-----
 block/sheepdog.c          | 20 +++++-----
 hmp-commands.hx           | 18 ++++-----
 hmp.c                     | 27 ++++++++++++++
 hmp.h                     |  1 +
 include/block/block.h     |  5 ++-
 include/block/block_int.h |  5 ++-
 include/sysemu/sysemu.h   |  8 ++--
 migration.c               |  6 +--
 qapi-schema.json          | 22 +++++++++++
 qemu-img.c                | 27 ++++++++------
 qmp-commands.hx           | 43 ++++++++++++++++++++++
 savevm.c                  | 93 ++++++++++++++++++++++++++++-------------------
 16 files changed, 235 insertions(+), 102 deletions(-)

-- 
1.8.1.4

[Qemu-devel] [PATCH v3 01/11] block: add error parameter to bdrv_snapshot_create() and related functions

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 block.c                   | 22 ++++++++++++++++------
 block/qcow2-snapshot.c    |  9 ++++++++-
 block/qcow2.h             |  4 +++-
 block/rbd.c               |  8 ++++++--
 block/sheepdog.c          | 17 +++++++++--------
 include/block/block.h     |  3 ++-
 include/block/block_int.h |  3 ++-
 qemu-img.c                |  2 +-
 savevm.c                  |  2 +-
 9 files changed, 48 insertions(+), 22 deletions(-)

diff --git a/block.c b/block.c
index 16a92a4..69f996e 100644
--- a/block.c
+++ b/block.c
@@ -3301,15 +3301,25 @@ BlockDriverState *bdrv_snapshots(void)
 }
 
 int bdrv_snapshot_create(BlockDriverState *bs,
-                         QEMUSnapshotInfo *sn_info)
+                         QEMUSnapshotInfo *sn_info,
+                         Error **errp)
 {
     BlockDriver *drv = bs->drv;
-    if (!drv)
+
+    if (!drv) {
+        error_setg(errp, "device '%s' has no medium",
+                   bdrv_get_device_name(bs));
         return -ENOMEDIUM;
-    if (drv->bdrv_snapshot_create)
-        return drv->bdrv_snapshot_create(bs, sn_info);
-    if (bs->file)
-        return bdrv_snapshot_create(bs->file, sn_info);
+    }
+    if (drv->bdrv_snapshot_create) {
+        return drv->bdrv_snapshot_create(bs, sn_info, errp);
+    }
+    if (bs->file) {
+        return bdrv_snapshot_create(bs->file, sn_info, errp);
+    }
+
+    error_setg(errp, "snapshot is not supported for '%s'",
+               bdrv_get_format_name(bs));
     return -ENOTSUP;
 }
 
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 992a5c8..b34179e 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -315,7 +315,9 @@ static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
 }
 
 /* if no id is provided, a new one is constructed */
-int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
+int qcow2_snapshot_create(BlockDriverState *bs,
+                          QEMUSnapshotInfo *sn_info,
+                          Error **errp)
 {
     BDRVQcowState *s = bs->opaque;
     QCowSnapshot *new_snapshot_list = NULL;
@@ -334,6 +336,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
 
     /* Check that the ID is unique */
     if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) {
+        error_setg(errp, "parameter 'name' has to be unique ID");
         return -EEXIST;
     }
 
@@ -351,6 +354,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
     if (l1_table_offset < 0) {
         ret = l1_table_offset;
+        error_setg(errp, "failed to allocate L1 table");
         goto fail;
     }
 
@@ -365,6 +369,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table,
                       s->l1_size * sizeof(uint64_t));
     if (ret < 0) {
+        error_setg(errp, "failed to save L1 table");
         goto fail;
     }
 
@@ -378,6 +383,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
      */
     ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
     if (ret < 0) {
+        error_setg(errp, "failed to update snapshot refcount");
         goto fail;
     }
 
@@ -395,6 +401,7 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     if (ret < 0) {
         g_free(s->snapshots);
         s->snapshots = old_snapshot_list;
+        error_setg(errp, "failed to write new snapshots");
         goto fail;
     }
 
diff --git a/block/qcow2.h b/block/qcow2.h
index e4b5e11..35ef293 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -353,7 +353,9 @@ int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
 
 /* qcow2-snapshot.c functions */
-int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
+int qcow2_snapshot_create(BlockDriverState *bs,
+                          QEMUSnapshotInfo *sn_info,
+                          Error **errp);
 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
diff --git a/block/rbd.c b/block/rbd.c
index 1a8ea6d..cdbee18 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -816,12 +816,14 @@ static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset)
 }
 
 static int qemu_rbd_snap_create(BlockDriverState *bs,
-                                QEMUSnapshotInfo *sn_info)
+                                QEMUSnapshotInfo *sn_info,
+                                Error **errp)
 {
     BDRVRBDState *s = bs->opaque;
     int r;
 
     if (sn_info->name[0] == '\0') {
+        error_setg(errp, "parameter 'name' cannot be empty");
         return -EINVAL; /* we need a name for rbd snapshots */
     }
 
@@ -831,16 +833,18 @@ static int qemu_rbd_snap_create(BlockDriverState *bs,
      */
     if (sn_info->id_str[0] != '\0' &&
         strcmp(sn_info->id_str, sn_info->name) != 0) {
+        error_setg(errp, "ID and name have to be equal");
         return -EINVAL;
     }
 
     if (strlen(sn_info->name) >= sizeof(sn_info->id_str)) {
+        error_setg(errp, "parameter 'name' has to be shorter than 127 chars");
         return -ERANGE;
     }
 
     r = rbd_snap_create(s->image, sn_info->name);
     if (r < 0) {
-        error_report("failed to create snap: %s", strerror(-r));
+        error_setg_errno(errp, -r, "failed to create snapshot");
         return r;
     }
 
diff --git a/block/sheepdog.c b/block/sheepdog.c
index bb67c4c..e38bdf5 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -1767,7 +1767,9 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
     return acb->ret;
 }
 
-static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
+static int sd_snapshot_create(BlockDriverState *bs,
+                              QEMUSnapshotInfo *sn_info,
+                              Error **errp)
 {
     BDRVSheepdogState *s = bs->opaque;
     int ret, fd;
@@ -1780,9 +1782,8 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
             s->name, sn_info->vm_state_size, s->is_snapshot);
 
     if (s->is_snapshot) {
-        error_report("You can't create a snapshot of a snapshot VDI, "
-                     "%s (%" PRIu32 ").", s->name, s->inode.vdi_id);
-
+        error_setg(errp, "you can't create a snapshot '%s' of a snapshot VDI "
+                   "%s (%" PRIu32 ")", sn_info->name, s->name, s->inode.vdi_id);
         return -EINVAL;
     }
 
@@ -1801,21 +1802,21 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     fd = connect_to_sdog(s);
     if (fd < 0) {
         ret = fd;
+        error_setg_errno(errp, errno, "failed to connect to sdog");
         goto cleanup;
     }
 
     ret = write_object(fd, (char *)&s->inode, vid_to_vdi_oid(s->inode.vdi_id),
                        s->inode.nr_copies, datalen, 0, false, s->cache_flags);
     if (ret < 0) {
-        error_report("failed to write snapshot's inode.");
+        error_setg_errno(errp, errno, "failed to write snapshot's inode");
         goto cleanup;
     }
 
     ret = do_sd_create(s, s->name, s->inode.vdi_size, s->inode.vdi_id, &new_vid,
                        1);
     if (ret < 0) {
-        error_report("failed to create inode for snapshot. %s",
-                     strerror(errno));
+        error_setg_errno(errp, errno, "failed to create inode for snapshot");
         goto cleanup;
     }
 
@@ -1825,7 +1826,7 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
                       s->inode.nr_copies, datalen, 0, s->cache_flags);
 
     if (ret < 0) {
-        error_report("failed to read new inode info. %s", strerror(errno));
+        error_setg_errno(errp, errno, "failed to read new inode info");
         goto cleanup;
     }
 
diff --git a/include/block/block.h b/include/block/block.h
index 9dc6aad..ee9399c 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -332,7 +332,8 @@ int bdrv_can_snapshot(BlockDriverState *bs);
 int bdrv_is_snapshot(BlockDriverState *bs);
 BlockDriverState *bdrv_snapshots(void);
 int bdrv_snapshot_create(BlockDriverState *bs,
-                         QEMUSnapshotInfo *sn_info);
+                         QEMUSnapshotInfo *sn_info,
+                         Error **errp);
 int bdrv_snapshot_goto(BlockDriverState *bs,
                        const char *snapshot_id);
 int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 0986a2d..2feaa16 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -154,7 +154,8 @@ struct BlockDriver {
                                  const uint8_t *buf, int nb_sectors);
 
     int (*bdrv_snapshot_create)(BlockDriverState *bs,
-                                QEMUSnapshotInfo *sn_info);
+                                QEMUSnapshotInfo *sn_info,
+                                Error **errp);
     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
                               const char *snapshot_id);
     int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char *snapshot_id);
diff --git a/qemu-img.c b/qemu-img.c
index 31627b0..21d02bf 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2012,7 +2012,7 @@ static int img_snapshot(int argc, char **argv)
         sn.date_sec = tv.tv_sec;
         sn.date_nsec = tv.tv_usec * 1000;
 
-        ret = bdrv_snapshot_create(bs, &sn);
+        ret = bdrv_snapshot_create(bs, &sn, NULL);
         if (ret) {
             error_report("Could not create snapshot '%s': %d (%s)",
                 snapshot_name, ret, strerror(-ret));
diff --git a/savevm.c b/savevm.c
index 406caa9..77c5291 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2332,7 +2332,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
         if (bdrv_can_snapshot(bs1)) {
             /* Write VM state size only to the image that contains the state */
             sn->vm_state_size = (bs == bs1 ? vm_state_size : 0);
-            ret = bdrv_snapshot_create(bs1, sn);
+            ret = bdrv_snapshot_create(bs1, sn, NULL);
             if (ret < 0) {
                 monitor_printf(mon, "Error while creating snapshot on '%s'\n",
                                bdrv_get_device_name(bs1));
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 02/11] block: add error parameter to del_existing_snapshots()

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 savevm.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/savevm.c b/savevm.c
index 77c5291..dc1f4a4 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2224,7 +2224,7 @@ static int bdrv_snapshot_find(BlockDriverState *bs, QEMUSnapshotInfo *sn_info,
 /*
  * Deletes snapshots of a given name in all opened images.
  */
-static int del_existing_snapshots(Monitor *mon, const char *name)
+static int del_existing_snapshots(const char *name, Error **errp)
 {
     BlockDriverState *bs;
     QEMUSnapshotInfo sn1, *snapshot = &sn1;
@@ -2237,9 +2237,8 @@ static int del_existing_snapshots(Monitor *mon, const char *name)
         {
             ret = bdrv_snapshot_delete(bs, name);
             if (ret < 0) {
-                monitor_printf(mon,
-                               "Error while deleting snapshot on '%s'\n",
-                               bdrv_get_device_name(bs));
+                error_setg(errp, "error while deleting snapshot on '%s'",
+                           bdrv_get_device_name(bs));
                 return -1;
             }
         }
@@ -2259,6 +2258,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
     qemu_timeval tv;
     struct tm tm;
     const char *name = qdict_get_try_str(qdict, "name");
+    Error *local_err = NULL;
 
     /* Verify if there is a device that doesn't support snapshots and is writable */
     bs = NULL;
@@ -2307,7 +2307,9 @@ void do_savevm(Monitor *mon, const QDict *qdict)
     }
 
     /* Delete old snapshots of the same name */
-    if (name && del_existing_snapshots(mon, name) < 0) {
+    if (name && del_existing_snapshots(name, &local_err) < 0) {
+        monitor_printf(mon, "%s\n", error_get_pretty(local_err));
+        error_free(local_err);
         goto the_end;
     }
 
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 03/11] savevm: add error parameter to qemu_savevm_state_begin()

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/sysemu/sysemu.h | 3 ++-
 migration.c             | 2 +-
 savevm.c                | 5 +++--
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 6578782..2f35a05 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -74,7 +74,8 @@ void qemu_announce_self(void);
 
 bool qemu_savevm_state_blocked(Error **errp);
 void qemu_savevm_state_begin(QEMUFile *f,
-                             const MigrationParams *params);
+                             const MigrationParams *params,
+                             Error **errp);
 int qemu_savevm_state_iterate(QEMUFile *f);
 void qemu_savevm_state_complete(QEMUFile *f);
 void qemu_savevm_state_cancel(void);
diff --git a/migration.c b/migration.c
index 7fb2147..d517dd6 100644
--- a/migration.c
+++ b/migration.c
@@ -505,7 +505,7 @@ static void *migration_thread(void *opaque)
     bool old_vm_running = false;
 
     DPRINTF("beginning savevm\n");
-    qemu_savevm_state_begin(s->file, &s->params);
+    qemu_savevm_state_begin(s->file, &s->params, NULL);
 
     while (s->state == MIG_STATE_ACTIVE) {
         int64_t current_time;
diff --git a/savevm.c b/savevm.c
index dc1f4a4..56da096 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1731,7 +1731,8 @@ bool qemu_savevm_state_blocked(Error **errp)
 }
 
 void qemu_savevm_state_begin(QEMUFile *f,
-                             const MigrationParams *params)
+                             const MigrationParams *params,
+                             Error **errp)
 {
     SaveStateEntry *se;
     int ret;
@@ -1921,7 +1922,7 @@ static int qemu_savevm_state(QEMUFile *f)
     }
 
     qemu_mutex_unlock_iothread();
-    qemu_savevm_state_begin(f, &params);
+    qemu_savevm_state_begin(f, &params, NULL);
     qemu_mutex_lock_iothread();
 
     while (qemu_file_get_error(f) == 0) {
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 04/11] savevm: add error parameter to qemu_savevm_state_iterate()

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/sysemu/sysemu.h | 2 +-
 migration.c             | 2 +-
 savevm.c                | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 2f35a05..af4f699 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -76,7 +76,7 @@ bool qemu_savevm_state_blocked(Error **errp);
 void qemu_savevm_state_begin(QEMUFile *f,
                              const MigrationParams *params,
                              Error **errp);
-int qemu_savevm_state_iterate(QEMUFile *f);
+int qemu_savevm_state_iterate(QEMUFile *f, Error **errp);
 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);
diff --git a/migration.c b/migration.c
index d517dd6..e9d2f40 100644
--- a/migration.c
+++ b/migration.c
@@ -516,7 +516,7 @@ static void *migration_thread(void *opaque)
             pending_size = qemu_savevm_state_pending(s->file, max_size);
             DPRINTF("pending size %lu max %lu\n", pending_size, max_size);
             if (pending_size && pending_size >= max_size) {
-                qemu_savevm_state_iterate(s->file);
+                qemu_savevm_state_iterate(s->file, NULL);
             } else {
                 DPRINTF("done iterating\n");
                 qemu_mutex_lock_iothread();
diff --git a/savevm.c b/savevm.c
index 56da096..575f1b2 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1784,7 +1784,7 @@ void qemu_savevm_state_begin(QEMUFile *f,
  *   0 : We haven't finished, caller have to go again
  *   1 : We have finished, we can go to complete phase
  */
-int qemu_savevm_state_iterate(QEMUFile *f)
+int qemu_savevm_state_iterate(QEMUFile *f, Error **errp)
 {
     SaveStateEntry *se;
     int ret = 1;
@@ -1926,7 +1926,7 @@ static int qemu_savevm_state(QEMUFile *f)
     qemu_mutex_lock_iothread();
 
     while (qemu_file_get_error(f) == 0) {
-        if (qemu_savevm_state_iterate(f) > 0) {
+        if (qemu_savevm_state_iterate(f, NULL) > 0) {
             break;
         }
     }
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 05/11] savevm: add error parameter to qemu_savevm_state_complete()

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/sysemu/sysemu.h | 2 +-
 migration.c             | 2 +-
 savevm.c                | 5 +++--
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index af4f699..9e6a4a9 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -77,7 +77,7 @@ void qemu_savevm_state_begin(QEMUFile *f,
                              const MigrationParams *params,
                              Error **errp);
 int qemu_savevm_state_iterate(QEMUFile *f, Error **errp);
-void qemu_savevm_state_complete(QEMUFile *f);
+void qemu_savevm_state_complete(QEMUFile *f, Error **errp);
 void qemu_savevm_state_cancel(void);
 uint64_t qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size);
 int qemu_loadvm_state(QEMUFile *f);
diff --git a/migration.c b/migration.c
index e9d2f40..c891a45 100644
--- a/migration.c
+++ b/migration.c
@@ -525,7 +525,7 @@ static void *migration_thread(void *opaque)
                 old_vm_running = runstate_is_running();
                 vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
                 qemu_file_set_rate_limit(s->file, INT_MAX);
-                qemu_savevm_state_complete(s->file);
+                qemu_savevm_state_complete(s->file, NULL);
                 qemu_mutex_unlock_iothread();
                 if (!qemu_file_get_error(s->file)) {
                     migrate_finish_set_state(s, MIG_STATE_COMPLETED);
diff --git a/savevm.c b/savevm.c
index 575f1b2..7598934 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1823,7 +1823,7 @@ int qemu_savevm_state_iterate(QEMUFile *f, Error **errp)
     return ret;
 }
 
-void qemu_savevm_state_complete(QEMUFile *f)
+void qemu_savevm_state_complete(QEMUFile *f, Error **errp)
 {
     SaveStateEntry *se;
     int ret;
@@ -1848,6 +1848,7 @@ void qemu_savevm_state_complete(QEMUFile *f)
         trace_savevm_section_end(se->section_id);
         if (ret < 0) {
             qemu_file_set_error(f, ret);
+            error_setg(errp, "failed to complete vmstate save");
             return;
         }
     }
@@ -1933,7 +1934,7 @@ static int qemu_savevm_state(QEMUFile *f)
 
     ret = qemu_file_get_error(f);
     if (ret == 0) {
-        qemu_savevm_state_complete(f);
+        qemu_savevm_state_complete(f, NULL);
         ret = qemu_file_get_error(f);
     }
     if (ret != 0) {
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 06/11] savevm: add error parameter to qemu_savevm_state()

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 savevm.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/savevm.c b/savevm.c
index 7598934..3c1ac9e 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1910,7 +1910,7 @@ void qemu_savevm_state_cancel(void)
     }
 }
 
-static int qemu_savevm_state(QEMUFile *f)
+static int qemu_savevm_state(QEMUFile *f, Error **errp)
 {
     int ret;
     MigrationParams params = {
@@ -1918,23 +1918,23 @@ static int qemu_savevm_state(QEMUFile *f)
         .shared = 0
     };
 
-    if (qemu_savevm_state_blocked(NULL)) {
+    if (qemu_savevm_state_blocked(errp)) {
         return -EINVAL;
     }
 
     qemu_mutex_unlock_iothread();
-    qemu_savevm_state_begin(f, &params, NULL);
+    qemu_savevm_state_begin(f, &params, errp);
     qemu_mutex_lock_iothread();
 
     while (qemu_file_get_error(f) == 0) {
-        if (qemu_savevm_state_iterate(f, NULL) > 0) {
+        if (qemu_savevm_state_iterate(f, errp) > 0) {
             break;
         }
     }
 
     ret = qemu_file_get_error(f);
     if (ret == 0) {
-        qemu_savevm_state_complete(f, NULL);
+        qemu_savevm_state_complete(f, errp);
         ret = qemu_file_get_error(f);
     }
     if (ret != 0) {
@@ -2321,7 +2321,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
         monitor_printf(mon, "Could not open VM state file\n");
         goto the_end;
     }
-    ret = qemu_savevm_state(f);
+    ret = qemu_savevm_state(f, NULL);
     vm_state_size = qemu_ftell(f);
     qemu_fclose(f);
     if (ret < 0) {
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 07/11] qapi: Convert savevm

[Pavel Hrdina]

QMP command "vm-snapshot-save" has also extra optional force parameter
and name parameter isn't optional anymore. It also returns information
about created snapshot.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 hmp-commands.hx         |  4 ++--
 hmp.c                   | 11 +++++++++
 hmp.h                   |  1 +
 include/sysemu/sysemu.h |  1 -
 qapi-schema.json        | 22 ++++++++++++++++++
 qmp-commands.hx         | 43 ++++++++++++++++++++++++++++++++++
 savevm.c                | 62 +++++++++++++++++++++++++++++++------------------
 7 files changed, 118 insertions(+), 26 deletions(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 3d98604..382b87d 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -310,7 +310,7 @@ ETEXI
         .args_type  = "name:s?",
         .params     = "[tag|id]",
         .help       = "save a VM snapshot. If no tag or id are provided, a new snapshot is created",
-        .mhandler.cmd = do_savevm,
+        .mhandler.cmd = hmp_vm_snapshot_save,
     },
 
 STEXI
@@ -318,7 +318,7 @@ STEXI
 @findex savevm
 Create a snapshot of the whole virtual machine. If @var{tag} is
 provided, it is used as human readable identifier. If there is already
-a snapshot with the same tag or ID, it is replaced. More info at
+a snapshot with the same @var{tag} or @var{id}, it is replaced. More info at
 @ref{vm_snapshots}.
 ETEXI
 
diff --git a/hmp.c b/hmp.c
index dbe9b90..b38b6ce 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1433,3 +1433,14 @@ void hmp_chardev_remove(Monitor *mon, const QDict *qdict)
     qmp_chardev_remove(qdict_get_str(qdict, "id"), &local_err);
     hmp_handle_error(mon, &local_err);
 }
+
+void hmp_vm_snapshot_save(Monitor *mon, const QDict *qdict)
+{
+    const char *name = qdict_get_try_str(qdict, "name");
+    Error *err = NULL;
+    SnapshotInfo *info = NULL;
+
+    info = qmp_vm_snapshot_save(!!name, name, true, true, &err);
+    qapi_free_SnapshotInfo(info);
+    hmp_handle_error(mon, &err);
+}
diff --git a/hmp.h b/hmp.h
index 80e8b41..1bb8590 100644
--- a/hmp.h
+++ b/hmp.h
@@ -86,5 +86,6 @@ void hmp_nbd_server_add(Monitor *mon, const QDict *qdict);
 void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
 void hmp_chardev_add(Monitor *mon, const QDict *qdict);
 void hmp_chardev_remove(Monitor *mon, const QDict *qdict);
+void hmp_vm_snapshot_save(Monitor *mon, const QDict *qdict);
 
 #endif
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 9e6a4a9..87b82d7 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -65,7 +65,6 @@ void qemu_remove_exit_notifier(Notifier *notify);
 
 void qemu_add_machine_init_done_notifier(Notifier *notify);
 
-void do_savevm(Monitor *mon, const QDict *qdict);
 int load_vmstate(const char *name);
 void do_delvm(Monitor *mon, const QDict *qdict);
 void do_info_snapshots(Monitor *mon, const QDict *qdict);
diff --git a/qapi-schema.json b/qapi-schema.json
index f629a24..c00f782 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -3453,3 +3453,25 @@
 # Since: 1.5
 ##
 { 'command': 'query-tpm', 'returns': ['TPMInfo'] }
+
+##
+# @vm-snapshot-save:
+#
+# Create a snapshot of the whole virtual machine. If tag is provided as @name,
+# it is used as human readable identifier. If there is already a snapshot
+# with the same tag or id, the force argument needs to be true to replace it.
+#
+# The VM is automatically stopped and resumed and saving a snapshot can take
+# a long time.
+#
+# @name: #optional tag of new snapshot or tag|id of existing snapshot
+#
+# @force: #optional specify whether existing snapshot is replaced or not,
+#         default is false
+#
+# Returns: Nothing on success
+#
+# Since: 1.5
+##
+{ 'command': 'vm-snapshot-save', 'data': {'*name': 'str', '*force': 'bool'},
+  'returns': 'SnapshotInfo' }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 1e0e11e..119e7a5 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1445,6 +1445,49 @@ Example:
 
 EQMP
     {
+        .name       = "vm-snapshot-save",
+        .args_type  = "name:s?,force:b?",
+        .params     = "[name] [force]",
+        .help       = "save a VM snapshot, to replace existing snapshot use force parameter",
+        .mhandler.cmd_new = qmp_marshal_input_vm_snapshot_save
+    },
+
+SQMP
+vm-snapshot-save
+------
+
+Create a snapshot of the whole virtual machine. If tag is provided as name,
+it is used as human readable identifier. If there is already a snapshot with
+the same tag, the force argument needs to be true to replace it.
+
+The VM is automatically stopped and resumed and saving a snapshot can take
+a long time.
+
+Arguments:
+
+- "name": tag of new snapshot or tag|id of existing snapshot
+          (json-string, optional)
+
+- "force": specify whether existing snapshot is replaced or not,
+           default is false (json-bool, optional)
+
+Example:
+
+-> { "execute": "vm-snapshot-save", "arguments": { "name": "my_snapshot" } }
+<- {
+      "return": {
+         "id": "1",
+         "name": "my_snapshot",
+         "date-sec": 1364480534,
+         "date-nsec": 978215000,
+         "vm-clock-sec": 5,
+         "vm-clock-nsec": 153620449,
+         "vm-state-size": 5709953
+      }
+   }
+
+EQMP
+    {
         .name       = "qmp_capabilities",
         .args_type  = "",
         .params     = "",
diff --git a/savevm.c b/savevm.c
index 3c1ac9e..38d6950 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2249,17 +2249,18 @@ static int del_existing_snapshots(const char *name, Error **errp)
     return 0;
 }
 
-void do_savevm(Monitor *mon, const QDict *qdict)
+SnapshotInfo *qmp_vm_snapshot_save(bool has_name, const char *name,
+                                  bool has_force, bool force, Error **errp)
 {
     BlockDriverState *bs, *bs1;
     QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
+    SnapshotInfo *info = NULL;
     int ret;
     QEMUFile *f;
     int saved_vm_running;
     uint64_t vm_state_size;
     qemu_timeval tv;
     struct tm tm;
-    const char *name = qdict_get_try_str(qdict, "name");
     Error *local_err = NULL;
 
     /* Verify if there is a device that doesn't support snapshots and is writable */
@@ -2271,16 +2272,16 @@ void do_savevm(Monitor *mon, const QDict *qdict)
         }
 
         if (!bdrv_can_snapshot(bs)) {
-            monitor_printf(mon, "Device '%s' is writable but does not support snapshots.\n",
-                               bdrv_get_device_name(bs));
-            return;
+            error_setg(errp, "Device '%s' is writable but does not support "
+                       "snapshots.", bdrv_get_device_name(bs));
+            return NULL;
         }
     }
 
     bs = bdrv_snapshots();
     if (!bs) {
-        monitor_printf(mon, "No block device can accept snapshots\n");
-        return;
+        error_setg(errp, "No block device can accept snapshots.");
+        return NULL;
     }
 
     saved_vm_running = runstate_is_running();
@@ -2294,11 +2295,23 @@ void do_savevm(Monitor *mon, const QDict *qdict)
     sn->date_nsec = tv.tv_usec * 1000;
     sn->vm_clock_nsec = qemu_get_clock_ns(vm_clock);
 
-    if (name) {
+    if (has_name) {
         ret = bdrv_snapshot_find(bs, old_sn, name);
         if (ret >= 0) {
-            pstrcpy(sn->name, sizeof(sn->name), old_sn->name);
-            pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str);
+            if (has_force && force) {
+                pstrcpy(sn->name, sizeof(sn->name), old_sn->name);
+                pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str);
+
+                /* Delete old snapshots of the same name */
+                if (del_existing_snapshots(name, &local_err) < 0) {
+                    error_propagate(errp, local_err);
+                    goto the_end;
+                }
+            } else {
+                error_setg(errp, "Snapshot '%s' exists. For override use "
+                           "'force' parameter.", name);
+                goto the_end;
+            }
         } else {
             pstrcpy(sn->name, sizeof(sn->name), name);
         }
@@ -2308,24 +2321,17 @@ void do_savevm(Monitor *mon, const QDict *qdict)
         strftime(sn->name, sizeof(sn->name), "vm-%Y%m%d%H%M%S", &tm);
     }
 
-    /* Delete old snapshots of the same name */
-    if (name && del_existing_snapshots(name, &local_err) < 0) {
-        monitor_printf(mon, "%s\n", error_get_pretty(local_err));
-        error_free(local_err);
-        goto the_end;
-    }
-
     /* save the VM state */
     f = qemu_fopen_bdrv(bs, 1);
     if (!f) {
-        monitor_printf(mon, "Could not open VM state file\n");
+        error_setg(errp, "Failed to open '%s' file.", bdrv_get_device_name(bs));
         goto the_end;
     }
-    ret = qemu_savevm_state(f, NULL);
+    ret = qemu_savevm_state(f, &local_err);
     vm_state_size = qemu_ftell(f);
     qemu_fclose(f);
     if (ret < 0) {
-        monitor_printf(mon, "Error %d while writing VM\n", ret);
+        error_propagate(errp, local_err);
         goto the_end;
     }
 
@@ -2336,17 +2342,27 @@ void do_savevm(Monitor *mon, const QDict *qdict)
         if (bdrv_can_snapshot(bs1)) {
             /* Write VM state size only to the image that contains the state */
             sn->vm_state_size = (bs == bs1 ? vm_state_size : 0);
-            ret = bdrv_snapshot_create(bs1, sn, NULL);
+            ret = bdrv_snapshot_create(bs1, sn, &local_err);
             if (ret < 0) {
-                monitor_printf(mon, "Error while creating snapshot on '%s'\n",
-                               bdrv_get_device_name(bs1));
+                error_propagate(errp, local_err);
             }
         }
     }
 
+    info = g_malloc0(sizeof(SnapshotInfo));
+    info->id = g_strdup(sn->id_str);
+    info->name = g_strdup(sn->name);
+    info->date_nsec = sn->date_nsec;
+    info->date_sec = sn->date_sec;
+    info->vm_state_size = vm_state_size;
+    info->vm_clock_nsec = sn->vm_clock_nsec % 1000000000;
+    info->vm_clock_sec = sn->vm_clock_nsec / 1000000000;
+
  the_end:
     if (saved_vm_running)
         vm_start();
+
+    return info;
 }
 
 void qmp_xen_save_devices_state(const char *filename, Error **errp)
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 08/11] qemu-img: introduce qemu_img_handle_error

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 qemu-img.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/qemu-img.c b/qemu-img.c
index 21d02bf..d5f81cc 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -322,6 +322,17 @@ static int add_old_style_options(const char *fmt, QEMUOptionParameter *list,
     return 0;
 }
 
+static int qemu_img_handle_error(Error *err)
+{
+    if (error_is_set(&err)) {
+        error_report("%s", error_get_pretty(err));
+        error_free(err);
+        return 1;
+    }
+
+    return 0;
+}
+
 static int img_create(int argc, char **argv)
 {
     int c;
@@ -400,13 +411,8 @@ static int img_create(int argc, char **argv)
 
     bdrv_img_create(filename, fmt, base_filename, base_fmt,
                     options, img_size, BDRV_O_FLAGS, &local_err, quiet);
-    if (error_is_set(&local_err)) {
-        error_report("%s", error_get_pretty(local_err));
-        error_free(local_err);
-        return 1;
-    }
 
-    return 0;
+    return qemu_img_handle_error(local_err);
 }
 
 static void dump_json_image_check(ImageCheck *check, bool quiet)
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 09/11] block: update return value from bdrv_snapshot_create

[Pavel Hrdina]

If we provide error message we don't have to also provide return
value because we could check if there is any error message or not.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 block.c                   | 24 ++++++++++--------------
 block/qcow2-snapshot.c    | 12 +++++-------
 block/qcow2.h             |  6 +++---
 block/rbd.c               | 15 ++++++---------
 block/sheepdog.c          |  9 ++++-----
 include/block/block.h     |  6 +++---
 include/block/block_int.h |  6 +++---
 qemu-img.c                |  9 ++++-----
 savevm.c                  |  4 ++--
 9 files changed, 40 insertions(+), 51 deletions(-)

diff --git a/block.c b/block.c
index 69f996e..e701c0c 100644
--- a/block.c
+++ b/block.c
@@ -3300,27 +3300,23 @@ BlockDriverState *bdrv_snapshots(void)
     return NULL;
 }
 
-int bdrv_snapshot_create(BlockDriverState *bs,
-                         QEMUSnapshotInfo *sn_info,
-                         Error **errp)
+void bdrv_snapshot_create(BlockDriverState *bs,
+                          QEMUSnapshotInfo *sn_info,
+                          Error **errp)
 {
     BlockDriver *drv = bs->drv;
 
     if (!drv) {
         error_setg(errp, "device '%s' has no medium",
                    bdrv_get_device_name(bs));
-        return -ENOMEDIUM;
-    }
-    if (drv->bdrv_snapshot_create) {
-        return drv->bdrv_snapshot_create(bs, sn_info, errp);
-    }
-    if (bs->file) {
-        return bdrv_snapshot_create(bs->file, sn_info, errp);
+    } else if (drv->bdrv_snapshot_create) {
+        drv->bdrv_snapshot_create(bs, sn_info, errp);
+    } else if (bs->file) {
+        bdrv_snapshot_create(bs->file, sn_info, errp);
+    } else {
+        error_setg(errp, "snapshot is not supported for '%s'",
+                   bdrv_get_format_name(bs));
     }
-
-    error_setg(errp, "snapshot is not supported for '%s'",
-               bdrv_get_format_name(bs));
-    return -ENOTSUP;
 }
 
 int bdrv_snapshot_goto(BlockDriverState *bs,
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index b34179e..f49b95f 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -315,9 +315,9 @@ static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
 }
 
 /* if no id is provided, a new one is constructed */
-int qcow2_snapshot_create(BlockDriverState *bs,
-                          QEMUSnapshotInfo *sn_info,
-                          Error **errp)
+void qcow2_snapshot_create(BlockDriverState *bs,
+                           QEMUSnapshotInfo *sn_info,
+                           Error **errp)
 {
     BDRVQcowState *s = bs->opaque;
     QCowSnapshot *new_snapshot_list = NULL;
@@ -337,7 +337,7 @@ int qcow2_snapshot_create(BlockDriverState *bs,
     /* Check that the ID is unique */
     if (find_snapshot_by_id(bs, sn_info->id_str) >= 0) {
         error_setg(errp, "parameter 'name' has to be unique ID");
-        return -EEXIST;
+        return;
     }
 
     /* Populate sn with passed data */
@@ -413,14 +413,12 @@ int qcow2_snapshot_create(BlockDriverState *bs,
       qcow2_check_refcounts(bs, &result, 0);
     }
 #endif
-    return 0;
+    return;
 
 fail:
     g_free(sn->id_str);
     g_free(sn->name);
     g_free(l1_table);
-
-    return ret;
 }
 
 /* copy the snapshot 'snapshot_name' into the current disk image */
diff --git a/block/qcow2.h b/block/qcow2.h
index 35ef293..b23ea3f 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -353,9 +353,9 @@ int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
 
 /* qcow2-snapshot.c functions */
-int qcow2_snapshot_create(BlockDriverState *bs,
-                          QEMUSnapshotInfo *sn_info,
-                          Error **errp);
+void qcow2_snapshot_create(BlockDriverState *bs,
+                           QEMUSnapshotInfo *sn_info,
+                           Error **errp);
 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
diff --git a/block/rbd.c b/block/rbd.c
index cdbee18..5167f2c 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -815,16 +815,16 @@ static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset)
     return 0;
 }
 
-static int qemu_rbd_snap_create(BlockDriverState *bs,
-                                QEMUSnapshotInfo *sn_info,
-                                Error **errp)
+static void qemu_rbd_snap_create(BlockDriverState *bs,
+                                 QEMUSnapshotInfo *sn_info,
+                                 Error **errp)
 {
     BDRVRBDState *s = bs->opaque;
     int r;
 
     if (sn_info->name[0] == '\0') {
         error_setg(errp, "parameter 'name' cannot be empty");
-        return -EINVAL; /* we need a name for rbd snapshots */
+        return; /* we need a name for rbd snapshots */
     }
 
     /*
@@ -834,21 +834,18 @@ static int qemu_rbd_snap_create(BlockDriverState *bs,
     if (sn_info->id_str[0] != '\0' &&
         strcmp(sn_info->id_str, sn_info->name) != 0) {
         error_setg(errp, "ID and name have to be equal");
-        return -EINVAL;
+        return;
     }
 
     if (strlen(sn_info->name) >= sizeof(sn_info->id_str)) {
         error_setg(errp, "parameter 'name' has to be shorter than 127 chars");
-        return -ERANGE;
+        return;
     }
 
     r = rbd_snap_create(s->image, sn_info->name);
     if (r < 0) {
         error_setg_errno(errp, -r, "failed to create snapshot");
-        return r;
     }
-
-    return 0;
 }
 
 static int qemu_rbd_snap_remove(BlockDriverState *bs,
diff --git a/block/sheepdog.c b/block/sheepdog.c
index e38bdf5..cf11dfb 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -1767,9 +1767,9 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
     return acb->ret;
 }
 
-static int sd_snapshot_create(BlockDriverState *bs,
-                              QEMUSnapshotInfo *sn_info,
-                              Error **errp)
+static void sd_snapshot_create(BlockDriverState *bs,
+                               QEMUSnapshotInfo *sn_info,
+                               Error **errp)
 {
     BDRVSheepdogState *s = bs->opaque;
     int ret, fd;
@@ -1784,7 +1784,7 @@ static int sd_snapshot_create(BlockDriverState *bs,
     if (s->is_snapshot) {
         error_setg(errp, "you can't create a snapshot '%s' of a snapshot VDI "
                    "%s (%" PRIu32 ")", sn_info->name, s->name, s->inode.vdi_id);
-        return -EINVAL;
+        return;
     }
 
     dprintf("%s %s\n", sn_info->name, sn_info->id_str);
@@ -1836,7 +1836,6 @@ static int sd_snapshot_create(BlockDriverState *bs,
 
 cleanup:
     closesocket(fd);
-    return ret;
 }
 
 static int sd_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
diff --git a/include/block/block.h b/include/block/block.h
index ee9399c..1a6a6a7 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -331,9 +331,9 @@ BlockStats *bdrv_query_stats(const BlockDriverState *bs);
 int bdrv_can_snapshot(BlockDriverState *bs);
 int bdrv_is_snapshot(BlockDriverState *bs);
 BlockDriverState *bdrv_snapshots(void);
-int bdrv_snapshot_create(BlockDriverState *bs,
-                         QEMUSnapshotInfo *sn_info,
-                         Error **errp);
+void bdrv_snapshot_create(BlockDriverState *bs,
+                          QEMUSnapshotInfo *sn_info,
+                          Error **errp);
 int bdrv_snapshot_goto(BlockDriverState *bs,
                        const char *snapshot_id);
 int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 2feaa16..8760517 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -153,9 +153,9 @@ struct BlockDriver {
     int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num,
                                  const uint8_t *buf, int nb_sectors);
 
-    int (*bdrv_snapshot_create)(BlockDriverState *bs,
-                                QEMUSnapshotInfo *sn_info,
-                                Error **errp);
+    void (*bdrv_snapshot_create)(BlockDriverState *bs,
+                                 QEMUSnapshotInfo *sn_info,
+                                 Error **errp);
     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
                               const char *snapshot_id);
     int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char *snapshot_id);
diff --git a/qemu-img.c b/qemu-img.c
index d5f81cc..154d913 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1942,6 +1942,7 @@ static int img_snapshot(int argc, char **argv)
     int action = 0;
     qemu_timeval tv;
     bool quiet = false;
+    Error *local_err;
 
     bdrv_oflags = BDRV_O_FLAGS | BDRV_O_RDWR;
     /* Parse commandline parameters */
@@ -2018,11 +2019,9 @@ static int img_snapshot(int argc, char **argv)
         sn.date_sec = tv.tv_sec;
         sn.date_nsec = tv.tv_usec * 1000;
 
-        ret = bdrv_snapshot_create(bs, &sn, NULL);
-        if (ret) {
-            error_report("Could not create snapshot '%s': %d (%s)",
-                snapshot_name, ret, strerror(-ret));
-        }
+        local_err = NULL;
+        bdrv_snapshot_create(bs, &sn, &local_err);
+        ret = qemu_img_handle_error(local_err);
         break;
 
     case SNAPSHOT_APPLY:
diff --git a/savevm.c b/savevm.c
index 38d6950..0dce456 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2342,8 +2342,8 @@ SnapshotInfo *qmp_vm_snapshot_save(bool has_name, const char *name,
         if (bdrv_can_snapshot(bs1)) {
             /* Write VM state size only to the image that contains the state */
             sn->vm_state_size = (bs == bs1 ? vm_state_size : 0);
-            ret = bdrv_snapshot_create(bs1, sn, &local_err);
-            if (ret < 0) {
+            bdrv_snapshot_create(bs1, sn, &local_err);
+            if (error_is_set(&local_err)) {
                 error_propagate(errp, local_err);
             }
         }
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 10/11] savevm: update return value from qemu_savevm_state

[Pavel Hrdina]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 savevm.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/savevm.c b/savevm.c
index 0dce456..1e9ab4b 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1910,7 +1910,7 @@ void qemu_savevm_state_cancel(void)
     }
 }
 
-static int qemu_savevm_state(QEMUFile *f, Error **errp)
+static void qemu_savevm_state(QEMUFile *f, Error **errp)
 {
     int ret;
     MigrationParams params = {
@@ -1919,7 +1919,7 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
     };
 
     if (qemu_savevm_state_blocked(errp)) {
-        return -EINVAL;
+        return;
     }
 
     qemu_mutex_unlock_iothread();
@@ -1940,7 +1940,6 @@ static int qemu_savevm_state(QEMUFile *f, Error **errp)
     if (ret != 0) {
         qemu_savevm_state_cancel();
     }
-    return ret;
 }
 
 static int qemu_save_device_state(QEMUFile *f)
@@ -2327,10 +2326,10 @@ SnapshotInfo *qmp_vm_snapshot_save(bool has_name, const char *name,
         error_setg(errp, "Failed to open '%s' file.", bdrv_get_device_name(bs));
         goto the_end;
     }
-    ret = qemu_savevm_state(f, &local_err);
+    qemu_savevm_state(f, &local_err);
     vm_state_size = qemu_ftell(f);
     qemu_fclose(f);
-    if (ret < 0) {
+    if (error_is_set(&local_err)) {
         error_propagate(errp, local_err);
         goto the_end;
     }
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 11/11] savevm: add force parameter to HMP command and return snapshot info

[Pavel Hrdina]

HMP command "savevm" now takes extra optional force parameter to specify
whether replace existing snapshot or not. It also returns information
about created snapshot.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 hmp-commands.hx | 16 ++++++++--------
 hmp.c           | 18 +++++++++++++++++-
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 382b87d..9719cc0 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -307,19 +307,19 @@ ETEXI
 
     {
         .name       = "savevm",
-        .args_type  = "name:s?",
-        .params     = "[tag|id]",
-        .help       = "save a VM snapshot. If no tag or id are provided, a new snapshot is created",
+        .args_type  = "force:-f,name:s?",
+        .params     = "[-f] [tag|id]",
+        .help       = "save a VM snapshot, to replace existing snapshot use force flag",
         .mhandler.cmd = hmp_vm_snapshot_save,
     },
 
 STEXI
-@item savevm [@var{tag}|@var{id}]
+@item savevm [@var{-f}] @var{tag}|@var{id}
 @findex savevm
-Create a snapshot of the whole virtual machine. If @var{tag} is
-provided, it is used as human readable identifier. If there is already
-a snapshot with the same @var{tag} or @var{id}, it is replaced. More info at
-@ref{vm_snapshots}.
+Create a snapshot of the whole virtual machine. Parameter "name" is optional.
+If @var{tag} is provided, it is used as human readable identifier. If there is
+already a snapshot with the same @var{tag} or @var{id}, @var{-f} flag needs to
+be specified. More info at @ref{vm_snapshots}.
 ETEXI
 
     {
diff --git a/hmp.c b/hmp.c
index b38b6ce..adf586b 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1437,10 +1437,26 @@ void hmp_chardev_remove(Monitor *mon, const QDict *qdict)
 void hmp_vm_snapshot_save(Monitor *mon, const QDict *qdict)
 {
     const char *name = qdict_get_try_str(qdict, "name");
+    bool force = qdict_get_try_bool(qdict, "force", 0);
     Error *err = NULL;
     SnapshotInfo *info = NULL;
 
-    info = qmp_vm_snapshot_save(!!name, name, true, true, &err);
+    info = qmp_vm_snapshot_save(!!name, name, !!force, force, &err);
+
+    if (info) {
+        char buf[256];
+        QEMUSnapshotInfo sn = {
+            .vm_state_size = info->vm_state_size,
+            .date_sec = info->date_sec,
+            .date_nsec = info->date_nsec,
+            .vm_clock_nsec = info->vm_clock_sec * 1000000000 +
+                             info->vm_clock_nsec,
+        };
+        pstrcpy(sn.id_str, sizeof(sn.id_str), info->id);
+        pstrcpy(sn.name, sizeof(sn.name), info->name);
+        monitor_printf(mon, "%s\n", bdrv_snapshot_dump(buf, sizeof(buf), &sn));
+    }
+
     qapi_free_SnapshotInfo(info);
     hmp_handle_error(mon, &err);
 }
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH v3 01/11] block: add error parameter to bdrv_snapshot_create() and related functions

[Eric Blake]

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On 03/28/2013 10:47 AM, Pavel Hrdina wrote:
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  block.c                   | 22 ++++++++++++++++------
>  block/qcow2-snapshot.c    |  9 ++++++++-
>  block/qcow2.h             |  4 +++-
>  block/rbd.c               |  8 ++++++--
>  block/sheepdog.c          | 17 +++++++++--------
>  include/block/block.h     |  3 ++-
>  include/block/block_int.h |  3 ++-
>  qemu-img.c                |  2 +-
>  savevm.c                  |  2 +-
>  9 files changed, 48 insertions(+), 22 deletions(-)
> 

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

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH v3 07/11] qapi: Convert savevm

[Eric Blake]

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On 03/28/2013 10:47 AM, Pavel Hrdina wrote:
> QMP command "vm-snapshot-save" has also extra optional force parameter
> and name parameter isn't optional anymore. It also returns information
> about created snapshot.

Commit message is a bit stale from an earlier version of the series,
since name is still optional in this patch.

> +++ b/qapi-schema.json
> @@ -3453,3 +3453,25 @@
>  # Since: 1.5
>  ##
>  { 'command': 'query-tpm', 'returns': ['TPMInfo'] }
> +
> +##
> +# @vm-snapshot-save:
> +#
> +# Create a snapshot of the whole virtual machine. If tag is provided as @name,
> +# it is used as human readable identifier. If there is already a snapshot
> +# with the same tag or id, the force argument needs to be true to replace it.
> +#
> +# The VM is automatically stopped and resumed and saving a snapshot can take
> +# a long time.
> +#
> +# @name: #optional tag of new snapshot or tag|id of existing snapshot
> +#
> +# @force: #optional specify whether existing snapshot is replaced or not,
> +#         default is false
> +#
> +# Returns: Nothing on success

Comment is stale, now that you return the SnapshotInfo of the
newly-created snapshot.

> +#
> +# Since: 1.5
> +##
> +{ 'command': 'vm-snapshot-save', 'data': {'*name': 'str', '*force': 'bool'},
> +  'returns': 'SnapshotInfo' }

> +++ b/savevm.c
> @@ -2249,17 +2249,18 @@ static int del_existing_snapshots(const char *name, Error **errp)
>      return 0;
>  }
>  
> -void do_savevm(Monitor *mon, const QDict *qdict)
> +SnapshotInfo *qmp_vm_snapshot_save(bool has_name, const char *name,
> +                                  bool has_force, bool force, Error **errp)

Indentation is off by one (the two "bool has_" should be aligned).

> @@ -2271,16 +2272,16 @@ void do_savevm(Monitor *mon, const QDict *qdict)
>          }
>  
>          if (!bdrv_can_snapshot(bs)) {
> -            monitor_printf(mon, "Device '%s' is writable but does not support snapshots.\n",
> -                               bdrv_get_device_name(bs));
> -            return;
> +            error_setg(errp, "Device '%s' is writable but does not support "
> +                       "snapshots.", bdrv_get_device_name(bs));

Missed a removal of a trailing '.' in the error message.

> +            return NULL;
>          }
>      }
>  
>      bs = bdrv_snapshots();
>      if (!bs) {
> -        monitor_printf(mon, "No block device can accept snapshots\n");
> -        return;
> +        error_setg(errp, "No block device can accept snapshots.");

And completely added a trailing '.' here.

> +            if (has_force && force) {
> +                pstrcpy(sn->name, sizeof(sn->name), old_sn->name);
> +                pstrcpy(sn->id_str, sizeof(sn->id_str), old_sn->id_str);
> +
> +                /* Delete old snapshots of the same name */
> +                if (del_existing_snapshots(name, &local_err) < 0) {
> +                    error_propagate(errp, local_err);
> +                    goto the_end;
> +                }
> +            } else {
> +                error_setg(errp, "Snapshot '%s' exists. For override use "
> +                           "'force' parameter.", name);

New message with trailing '.'; maybe:

"cannot override existing snapshot '%s' without 'force' parameter"


>      /* save the VM state */
>      f = qemu_fopen_bdrv(bs, 1);
>      if (!f) {
> -        monitor_printf(mon, "Could not open VM state file\n");
> +        error_setg(errp, "Failed to open '%s' file.", bdrv_get_device_name(bs));

don't add a trailing '.'

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH v3 08/11] qemu-img: introduce qemu_img_handle_error

[Eric Blake]

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On 03/28/2013 10:47 AM, Pavel Hrdina wrote:
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  qemu-img.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)

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

> +static int qemu_img_handle_error(Error *err)
> +{
> +    if (error_is_set(&err)) {
> +        error_report("%s", error_get_pretty(err));
> +        error_free(err);
> +        return 1;

A non-bool positive number is unusual for errors (-1, or a true/false
scheme, tend to be more common)...

> -    if (error_is_set(&local_err)) {
> -        error_report("%s", error_get_pretty(local_err));
> -        error_free(local_err);
> -        return 1;

...but it is accurate code motion, so it doesn't impact my review.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH v3 09/11] block: update return value from bdrv_snapshot_create

[Eric Blake]

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On 03/28/2013 10:47 AM, Pavel Hrdina wrote:
> If we provide error message we don't have to also provide return
> value because we could check if there is any error message or not.
> 
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  block.c                   | 24 ++++++++++--------------
>  block/qcow2-snapshot.c    | 12 +++++-------
>  block/qcow2.h             |  6 +++---
>  block/rbd.c               | 15 ++++++---------
>  block/sheepdog.c          |  9 ++++-----
>  include/block/block.h     |  6 +++---
>  include/block/block_int.h |  6 +++---
>  qemu-img.c                |  9 ++++-----
>  savevm.c                  |  4 ++--
>  9 files changed, 40 insertions(+), 51 deletions(-)
> 

> @@ -2018,11 +2019,9 @@ static int img_snapshot(int argc, char **argv)
>          sn.date_sec = tv.tv_sec;
>          sn.date_nsec = tv.tv_usec * 1000;
>  
> -        ret = bdrv_snapshot_create(bs, &sn, NULL);
> -        if (ret) {
> -            error_report("Could not create snapshot '%s': %d (%s)",
> -                snapshot_name, ret, strerror(-ret));
> -        }
> +        local_err = NULL;
> +        bdrv_snapshot_create(bs, &sn, &local_err);
> +        ret = qemu_img_handle_error(local_err);

This sets ret==1 on error, but bdrv_snapshot_create used to return <0 on
error.  Then again, the tail of img_snapshot() normalizes all errors to
a 'return 1'.  Took me a few minutes to see, but no problem after all.

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

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH v3 08/11] qemu-img: introduce qemu_img_handle_error

[Eric Blake]

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On 03/28/2013 03:42 PM, Eric Blake wrote:
> On 03/28/2013 10:47 AM, Pavel Hrdina wrote:
>> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
>> ---
>>  qemu-img.c | 18 ++++++++++++------
>>  1 file changed, 12 insertions(+), 6 deletions(-)
> 
> Reviewed-by: Eric Blake <eblake@redhat.com>
> 
>> +static int qemu_img_handle_error(Error *err)
>> +{
>> +    if (error_is_set(&err)) {
>> +        error_report("%s", error_get_pretty(err));
>> +        error_free(err);
>> +        return 1;
> 
> A non-bool positive number is unusual for errors (-1, or a true/false
> scheme, tend to be more common)...
> 
>> -    if (error_is_set(&local_err)) {
>> -        error_report("%s", error_get_pretty(local_err));
>> -        error_free(local_err);
>> -        return 1;
> 
> ...but it is accurate code motion, so it doesn't impact my review.

And in reading 9/11, I found out why it struck me as unusual.  I usually
spell it EXIT_FAILURE instead of 1, for a return status intended to be
used in a final exit() or return from main().  But that's a pre-existing
syndrome that affects much more of qemu-img.c, not worth changing here.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH v3 10/11] savevm: update return value from qemu_savevm_state

[Eric Blake]

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On 03/28/2013 10:47 AM, Pavel Hrdina wrote:
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  savevm.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 

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

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH v3 11/11] savevm: add force parameter to HMP command and return snapshot info

[Eric Blake]

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On 03/28/2013 10:47 AM, Pavel Hrdina wrote:
> HMP command "savevm" now takes extra optional force parameter to specify
> whether replace existing snapshot or not. It also returns information
> about created snapshot.
> 
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  hmp-commands.hx | 16 ++++++++--------
>  hmp.c           | 18 +++++++++++++++++-
>  2 files changed, 25 insertions(+), 9 deletions(-)
> 

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

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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