This is in preparation to mark bdrv_drained_begin() as GRAPH_UNLOCKED.
More granular draining is not trivially possible, because
bdrv_snapshot_delete() can recursively call itself.
The return value of bdrv_all_delete_snapshot() changes from -1 to
-errno propagated from failed sub-calls. This is fine for the existing
callers of bdrv_all_delete_snapshot().
Signed-off-by: Fiona Ebner <f.eb...@proxmox.com>
---
Changes in v2:
* Use 'must be drained' instead of 'needs to be drained'.
* Use goto for cleanup/error handling in bdrv_all_delete_snapshot().
* Don't use atomics to access bs->quiesce_counter.
block/snapshot.c | 26 +++++++++++++++-----------
blockdev.c | 25 +++++++++++++++++--------
qemu-img.c | 2 ++
3 files changed, 34 insertions(+), 19 deletions(-)
diff --git a/block/snapshot.c b/block/snapshot.c
index 22567f1fb9..9f300a78bd 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -327,7 +327,7 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
/**
* Delete an internal snapshot by @snapshot_id and @name.
- * @bs: block device used in the operation
+ * @bs: block device used in the operation, must be drained
* @snapshot_id: unique snapshot ID, or NULL
* @name: snapshot name, or NULL
* @errp: location to store error
@@ -358,6 +358,8 @@ int bdrv_snapshot_delete(BlockDriverState *bs,
GLOBAL_STATE_CODE();
+ assert(bs->quiesce_counter > 0);
+
if (!drv) {
error_setg(errp, "Device '%s' has no medium",
bdrv_get_device_name(bs));
@@ -368,9 +370,6 @@ int bdrv_snapshot_delete(BlockDriverState *bs,
return -EINVAL;
}
- /* drain all pending i/o before deleting snapshot */
- bdrv_drained_begin(bs);
-
if (drv->bdrv_snapshot_delete) {
ret = drv->bdrv_snapshot_delete(bs, snapshot_id, name, errp);
} else if (fallback_bs) {
@@ -382,7 +381,6 @@ int bdrv_snapshot_delete(BlockDriverState *bs,
ret = -ENOTSUP;
}
- bdrv_drained_end(bs);
return ret;
}
@@ -571,19 +569,22 @@ int bdrv_all_delete_snapshot(const char *name,
ERRP_GUARD();
g_autoptr(GList) bdrvs = NULL;
GList *iterbdrvs;
+ int ret = 0;
GLOBAL_STATE_CODE();
- GRAPH_RDLOCK_GUARD_MAINLOOP();
- if (bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp) < 0)
{
- return -1;
+ bdrv_drain_all_begin();
+ bdrv_graph_rdlock_main_loop();
+
+ ret = bdrv_all_get_snapshot_devices(has_devices, devices, &bdrvs, errp);
+ if (ret < 0) {
+ goto out;
}
iterbdrvs = bdrvs;
while (iterbdrvs) {
BlockDriverState *bs = iterbdrvs->data;
QEMUSnapshotInfo sn1, *snapshot = &sn1;
- int ret = 0;
if ((devices || bdrv_all_snapshots_includes_bs(bs)) &&
bdrv_snapshot_find(bs, snapshot, name) >= 0)
@@ -594,13 +595,16 @@ int bdrv_all_delete_snapshot(const char *name,
if (ret < 0) {
error_prepend(errp, "Could not delete snapshot '%s' on '%s': ",
name, bdrv_get_device_or_node_name(bs));
- return -1;
+ goto out;
}
iterbdrvs = iterbdrvs->next;
}
- return 0;
+out:
+ bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_end();
+ return ret;
}
diff --git a/blockdev.c b/blockdev.c
index 21443b4514..3982f9776b 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1132,39 +1132,41 @@ SnapshotInfo
*qmp_blockdev_snapshot_delete_internal_sync(const char *device,
int ret;
GLOBAL_STATE_CODE();
- GRAPH_RDLOCK_GUARD_MAINLOOP();
+
+ bdrv_drain_all_begin();
+ bdrv_graph_rdlock_main_loop();
bs = qmp_get_root_bs(device, errp);
if (!bs) {
- return NULL;
+ goto error;
}
if (!id && !name) {
error_setg(errp, "Name or id must be provided");
- return NULL;
+ goto error;
}
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE, errp)) {
- return NULL;
+ goto error;
}
ret = bdrv_snapshot_find_by_id_and_name(bs, id, name, &sn, &local_err);
if (local_err) {
error_propagate(errp, local_err);
- return NULL;
+ goto error;
}
if (!ret) {
error_setg(errp,
"Snapshot with id '%s' and name '%s' does not exist on "
"device '%s'",
STR_OR_NULL(id), STR_OR_NULL(name), device);
- return NULL;
+ goto error;
}
bdrv_snapshot_delete(bs, id, name, &local_err);
if (local_err) {
error_propagate(errp, local_err);
- return NULL;
+ goto error;
}
info = g_new0(SnapshotInfo, 1);
@@ -1180,6 +1182,9 @@ SnapshotInfo
*qmp_blockdev_snapshot_delete_internal_sync(const char *device,
info->has_icount = true;
}
+error:
+ bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_end();
return info;
}
@@ -1295,12 +1300,14 @@ static void internal_snapshot_abort(void *opaque)
Error *local_error = NULL;
GLOBAL_STATE_CODE();
- GRAPH_RDLOCK_GUARD_MAINLOOP();
if (!state->created) {
return;
}
+ bdrv_drain_all_begin();
+ bdrv_graph_rdlock_main_loop();
+
if (bdrv_snapshot_delete(bs, sn->id_str, sn->name, &local_error) < 0) {
error_reportf_err(local_error,
"Failed to delete snapshot with id '%s' and "
@@ -1308,6 +1315,8 @@ static void internal_snapshot_abort(void *opaque)
sn->id_str, sn->name,
bdrv_get_device_name(bs));
}
+ bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_end();
}
static void internal_snapshot_clean(void *opaque)
diff --git a/qemu-img.c b/qemu-img.c
index 76ac5d3028..e81b0fbb6c 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -3505,6 +3505,7 @@ static int img_snapshot(int argc, char **argv)
break;
case SNAPSHOT_DELETE:
+ bdrv_drain_all_begin();
bdrv_graph_rdlock_main_loop();
ret = bdrv_snapshot_find(bs, &sn, snapshot_name);
if (ret < 0) {
@@ -3520,6 +3521,7 @@ static int img_snapshot(int argc, char **argv)
}
}
bdrv_graph_rdunlock_main_loop();
+ bdrv_drain_all_end();
break;
}
--
2.39.5
