On 04/21/2018 11:54 AM, Max Reitz wrote:
Looking at the qcow2 code that is riddled with error_report() calls,
this is really how it should have been from the start.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
+++ b/block/qcow2.c
@@ -4049,7 +4049,8 @@ static int qcow2_load_vmstate(BlockDriverState *bs,
QEMUIOVector *qiov,
* have to be removed.
*/
static int qcow2_downgrade(BlockDriverState *bs, int target_version,
- BlockDriverAmendStatusCB *status_cb, void
*cb_opaque)
+ BlockDriverAmendStatusCB *status_cb, void
*cb_opaque,
+ Error **errp)
{
BDRVQcow2State *s = bs->opaque;
int current_version = s->qcow_version;
@@ -4058,13 +4059,17 @@ static int qcow2_downgrade(BlockDriverState *bs, int
target_version,
if (target_version == current_version) {
return 0;
} else if (target_version > current_version) {
+ error_setg(errp, "Cannot downgrade an image from version %i to %i",
%i is unusual compared to %d, but as they do the same, I won't make you
change it, if we keep it. That said, this function is static; and the
lone caller qcow2_amend_options is already doing sanity checks, right?
(Yes - it does qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL), and then
validates that the user's information is in range, which already filters
out everything but v2 and v3; then _this_ function is called exactly for
3 downto 2). So this should be an assert() instead of an error message.
+ current_version, target_version);
return -EINVAL;
} else if (target_version != 2) {
+ error_setg(errp, "Cannot downgrade an image to version %i (only "
+ "target version 2 is supported)", target_version);
And again.
@@ -4072,6 +4077,8 @@ static int qcow2_downgrade(BlockDriverState *bs, int
target_version,
if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
ret = qcow2_mark_clean(bs);
if (ret < 0) {
+ error_setg(errp, "Failed to make the image clean: %s",
+ strerror(-ret));
error_setg_errno(), please.
@@ -4094,6 +4103,8 @@ static int qcow2_downgrade(BlockDriverState *bs, int
target_version,
ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque);
if (ret < 0) {
+ error_setg(errp, "Failed to turn zero into data clusters: %s",
+ strerror(-ret));
and again
return ret;
}
@@ -4101,6 +4112,8 @@ static int qcow2_downgrade(BlockDriverState *bs, int target_version,
ret = qcow2_update_header(bs);
if (ret < 0) {
s->qcow_version = current_version;
+ error_setg(errp, "Failed to update the image header: %s",
+ strerror(-ret));
etc. I'll quit pointing it out, but there are more.
@@ -4293,18 +4311,17 @@ static int qcow2_amend_options(BlockDriverState *bs,
QemuOpts *opts,
int refcount_order = ctz32(refcount_bits);
if (new_version < 3 && refcount_bits != 16) {
- error_report("Different refcount widths than 16 bits require "
- "compatibility level 1.1 or above (use compat=1.1 or "
- "greater)");
+ error_setg(errp, "Different refcount widths than 16 bits require "
+ "compatibility level 1.1 or above (use compat=1.1 or "
+ "greater)");
Not your fault, but that reads poorly. Better would be:
Refcount widths other than 16 bits require compatibility level 1.1 or above
+++ b/qemu-img.c
@@ -3730,10 +3730,10 @@ static int img_amend(int argc, char **argv)
/* In case the driver does not call amend_status_cb() */
qemu_progress_print(0.f, 0);
- ret = bdrv_amend_options(bs, opts, &amend_status_cb, NULL);
+ ret = bdrv_amend_options(bs, opts, &amend_status_cb, NULL, &err);
qemu_progress_print(100.f, 0);
if (ret < 0) {
- error_report("Error while amending options: %s", strerror(-ret));
+ error_report_err(err);
Definitely nicer, but does change various outputs; glad you fixed
iotests to match.
Overall a nice patch, looking forward to v2.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
