[Qemu-devel] [PATCH 02/11] block: update error reporting for bdrv_snapshot_delete() and related functions

[Pavel Hrdina <phrdina@redhat.com>]

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 block.c                   | 22 ++++++++++++++--------
 block/qcow2-snapshot.c    | 21 +++++++++++++++------
 block/qcow2.h             |  4 +++-
 block/rbd.c               | 11 ++++++++---
 block/sheepdog.c          |  6 ++++--
 include/block/block.h     |  4 +++-
 include/block/block_int.h |  4 +++-
 qemu-img.c                |  9 ++++-----
 savevm.c                  | 26 ++++++++++----------------
 9 files changed, 64 insertions(+), 43 deletions(-)

diff --git a/block.c b/block.c
index 4ad663d..fb065e6 100644
--- a/block.c
+++ b/block.c
@@ -3391,16 +3391,22 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
     return -ENOTSUP;
 }
 
-int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
+void bdrv_snapshot_delete(BlockDriverState *bs,
+                          const char *snapshot_id,
+                          Error **errp)
 {
     BlockDriver *drv = bs->drv;
-    if (!drv)
-        return -ENOMEDIUM;
-    if (drv->bdrv_snapshot_delete)
-        return drv->bdrv_snapshot_delete(bs, snapshot_id);
-    if (bs->file)
-        return bdrv_snapshot_delete(bs->file, snapshot_id);
-    return -ENOTSUP;
+
+    if (!drv) {
+        error_setg(errp, "device '%s' has no medium", bdrv_get_device_name(bs));
+    } else if (drv->bdrv_snapshot_delete) {
+        drv->bdrv_snapshot_delete(bs, snapshot_id, errp);
+    } else if (bs->file) {
+        bdrv_snapshot_delete(bs->file, snapshot_id, errp);
+    } else {
+        error_setg(errp, "snapshots are not supported on device '%s'",
+                   bdrv_get_device_name(bs));
+    }
 }
 
 int bdrv_snapshot_list(BlockDriverState *bs,
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 992a5c8..2ebeadc 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -530,7 +530,9 @@ fail:
     return ret;
 }
 
-int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
+void qcow2_snapshot_delete(BlockDriverState *bs,
+                           const char *snapshot_id,
+                           Error **errp)
 {
     BDRVQcowState *s = bs->opaque;
     QCowSnapshot sn;
@@ -539,7 +541,9 @@ int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
     /* Search the snapshot */
     snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
     if (snapshot_index < 0) {
-        return -ENOENT;
+        error_setg(errp, "qcow2: failed to find snapshot '%s' by id or name",
+                   snapshot_id);
+        return;
     }
     sn = s->snapshots[snapshot_index];
 
@@ -550,7 +554,9 @@ int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
     s->nb_snapshots--;
     ret = qcow2_write_snapshots(bs);
     if (ret < 0) {
-        return ret;
+        error_setg_errno(errp, -ret, "qcow2: failed to remove snapshot '%s' "
+                         "from snapshot list", sn.name);
+        return;
     }
 
     /*
@@ -567,14 +573,18 @@ int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
     ret = qcow2_update_snapshot_refcount(bs, sn.l1_table_offset,
                                          sn.l1_size, -1);
     if (ret < 0) {
-        return ret;
+        error_setg_errno(errp, -ret,
+                         "qcow2: failed to update snapshot refcount");
+        return;
     }
     qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * sizeof(uint64_t));
 
     /* must update the copied flag on the current cluster offsets */
     ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
     if (ret < 0) {
-        return ret;
+        error_setg_errno(errp, -ret,
+                         "qcow2: failed to update snapshot refcount");
+        return;
     }
 
 #ifdef DEBUG_ALLOC
@@ -583,7 +593,6 @@ int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
         qcow2_check_refcounts(bs, &result, 0);
     }
 #endif
-    return 0;
 }
 
 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
diff --git a/block/qcow2.h b/block/qcow2.h
index 9421843..dbd332d 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -384,7 +384,9 @@ 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_goto(BlockDriverState *bs, const char *snapshot_id);
-int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
+void qcow2_snapshot_delete(BlockDriverState *bs,
+                           const char *snapshot_id,
+                           Error **errp);
 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 
diff --git a/block/rbd.c b/block/rbd.c
index 141b488..c10edbf 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -871,14 +871,19 @@ static int qemu_rbd_snap_create(BlockDriverState *bs,
     return 0;
 }
 
-static int qemu_rbd_snap_remove(BlockDriverState *bs,
-                                const char *snapshot_name)
+static void qemu_rbd_snap_remove(BlockDriverState *bs,
+                                 const char *snapshot_name,
+                                 Error **errp)
 {
     BDRVRBDState *s = bs->opaque;
     int r;
 
     r = rbd_snap_remove(s->image, snapshot_name);
-    return r;
+    if (r < 0) {
+        error_setg_errno(errp, -r, "rbd: failed to remove snapshot '%s' on "
+                         "device '%s'", snapshot_name,
+                         bdrv_get_device_name(bs));
+    }
 }
 
 static int qemu_rbd_snap_rollback(BlockDriverState *bs,
diff --git a/block/sheepdog.c b/block/sheepdog.c
index 1c5b532..270fa64 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -1908,10 +1908,12 @@ out:
     return ret;
 }
 
-static int sd_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
+static void sd_snapshot_delete(BlockDriverState *bs,
+                               const char *snapshot_id,
+                               Error **errp)
 {
     /* FIXME: Delete specified snapshot id.  */
-    return 0;
+    return;
 }
 
 static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
diff --git a/include/block/block.h b/include/block/block.h
index ebd9512..db8c6aa 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -337,7 +337,9 @@ int bdrv_snapshot_create(BlockDriverState *bs,
                          QEMUSnapshotInfo *sn_info);
 int bdrv_snapshot_goto(BlockDriverState *bs,
                        const char *snapshot_id);
-int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
+void bdrv_snapshot_delete(BlockDriverState *bs,
+                          const char *snapshot_id,
+                          Error **errp);
 int bdrv_snapshot_list(BlockDriverState *bs,
                        QEMUSnapshotInfo **psn_info);
 int bdrv_snapshot_load_tmp(BlockDriverState *bs,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 458cde3..53c52bb 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -157,7 +157,9 @@ struct BlockDriver {
                                 QEMUSnapshotInfo *sn_info);
     int (*bdrv_snapshot_goto)(BlockDriverState *bs,
                               const char *snapshot_id);
-    int (*bdrv_snapshot_delete)(BlockDriverState *bs, const char *snapshot_id);
+    void (*bdrv_snapshot_delete)(BlockDriverState *bs,
+                                 const char *snapshot_id,
+                                 Error **errp);
     int (*bdrv_snapshot_list)(BlockDriverState *bs,
                               QEMUSnapshotInfo **psn_info);
     int (*bdrv_snapshot_load_tmp)(BlockDriverState *bs,
diff --git a/qemu-img.c b/qemu-img.c
index dbacdb7..4828fe4 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1936,6 +1936,7 @@ static int img_snapshot(int argc, char **argv)
 {
     BlockDriverState *bs;
     QEMUSnapshotInfo sn;
+    Error *local_err = NULL;
     char *filename, *snapshot_name = NULL;
     int c, ret = 0, bdrv_oflags;
     int action = 0;
@@ -2033,11 +2034,9 @@ static int img_snapshot(int argc, char **argv)
         break;
 
     case SNAPSHOT_DELETE:
-        ret = bdrv_snapshot_delete(bs, snapshot_name);
-        if (ret) {
-            error_report("Could not delete snapshot '%s': %d (%s)",
-                snapshot_name, ret, strerror(-ret));
-        }
+        bdrv_snapshot_delete(bs, snapshot_name, &local_err);
+        ret = qemu_img_handle_error("qemu-img snapshot delete failed",
+                                    local_err);
         break;
     }
 
diff --git a/savevm.c b/savevm.c
index 53515cb..6af84fd 100644
--- a/savevm.c
+++ b/savevm.c
@@ -2225,18 +2225,17 @@ static int del_existing_snapshots(Monitor *mon, const char *name)
 {
     BlockDriverState *bs;
     QEMUSnapshotInfo sn1, *snapshot = &sn1;
-    int ret;
+    Error *local_err = NULL;
 
     bs = NULL;
     while ((bs = bdrv_next(bs))) {
         if (bdrv_can_snapshot(bs) &&
             bdrv_snapshot_find(bs, snapshot, name) >= 0)
         {
-            ret = bdrv_snapshot_delete(bs, name);
-            if (ret < 0) {
-                monitor_printf(mon,
-                               "Error while deleting snapshot on '%s'\n",
-                               bdrv_get_device_name(bs));
+            bdrv_snapshot_delete(bs, name, &local_err);
+            if (error_is_set(&local_err)) {
+                monitor_printf(mon, "%s\n", error_get_pretty(local_err));
+                error_free(local_err);
                 return -1;
             }
         }
@@ -2450,7 +2449,7 @@ int load_vmstate(const char *name)
 void do_delvm(Monitor *mon, const QDict *qdict)
 {
     BlockDriverState *bs, *bs1;
-    int ret;
+    Error *local_err = NULL;
     const char *name = qdict_get_str(qdict, "name");
 
     bs = bdrv_snapshots();
@@ -2462,15 +2461,10 @@ void do_delvm(Monitor *mon, const QDict *qdict)
     bs1 = NULL;
     while ((bs1 = bdrv_next(bs1))) {
         if (bdrv_can_snapshot(bs1)) {
-            ret = bdrv_snapshot_delete(bs1, name);
-            if (ret < 0) {
-                if (ret == -ENOTSUP)
-                    monitor_printf(mon,
-                                   "Snapshots not supported on device '%s'\n",
-                                   bdrv_get_device_name(bs1));
-                else
-                    monitor_printf(mon, "Error %d while deleting snapshot on "
-                                   "'%s'\n", ret, bdrv_get_device_name(bs1));
+            bdrv_snapshot_delete(bs1, name, &local_err);
+            if (error_is_set(&local_err)) {
+                monitor_printf(mon, "%s\n", error_get_pretty(local_err));
+                error_free(local_err);
             }
         }
     }
-- 
1.8.1.4