Make use of qcow2_change_refcount_order() to support changing the
refcount order with qemu-img amend.
Signed-off-by: Max Reitz <mre...@redhat.com>
---
block/qcow2.c | 44 +++++++++++++++++++++++++++++++++++---------
1 file changed, 35 insertions(+), 9 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index e6b93d1..e8a6bb1 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2607,13 +2607,7 @@ static int qcow2_downgrade(BlockDriverState *bs, int
target_version,
}
if (s->refcount_order != 4) {
- /* we would have to convert the image to a refcount_order == 4 image
- * here; however, since qemu (at the time of writing this) does not
- * support anything different than 4 anyway, there is no point in doing
- * so right now; however, we should error out (if qemu supports this in
- * the future and this code has not been adapted) */
- error_report("qcow2_downgrade: Image refcount orders other than 4 are "
- "currently not supported.");
+ error_report("compat=0.10 requires refcount_width=16");
return -ENOTSUP;
}
@@ -2661,6 +2655,7 @@ typedef enum Qcow2AmendOperation {
* invocation from an operation change */
QCOW2_NO_OPERATION = 0,
+ QCOW2_CHANGING_REFCOUNT_ORDER,
QCOW2_DOWNGRADING,
} Qcow2AmendOperation;
@@ -2732,6 +2727,7 @@ static int qcow2_amend_options(BlockDriverState *bs,
QemuOpts *opts,
const char *compat = NULL;
uint64_t cluster_size = s->cluster_size;
bool encrypt;
+ int refcount_width = s->refcount_bits;
int ret;
QemuOptDesc *desc = opts->list->desc;
Qcow2AmendHelperCBInfo helper_cb_info;
@@ -2781,8 +2777,16 @@ static int qcow2_amend_options(BlockDriverState *bs,
QemuOpts *opts,
lazy_refcounts = qemu_opt_get_bool(opts, "lazy_refcounts",
lazy_refcounts);
} else if (!strcmp(desc->name, "refcount_width")) {
- error_report("Cannot change refcount entry width");
- return -ENOTSUP;
+ refcount_width = qemu_opt_get_number(opts, "refcount_width",
+ refcount_width);
+
+ if (refcount_width <= 0 || refcount_width > 64 ||
+ !is_power_of_2(refcount_width))
+ {
+ error_report("Refcount width must be a power of two and may "
+ "not exceed 64 bits");
+ return -EINVAL;
+ }
} else {
/* if this point is reached, this probably means a new option was
* added without having it covered here */
@@ -2796,6 +2800,7 @@ static int qcow2_amend_options(BlockDriverState *bs,
QemuOpts *opts,
.original_status_cb = status_cb,
.original_cb_opaque = cb_opaque,
.total_operations = (new_version < old_version)
+ + (s->refcount_bits != refcount_width)
};
/* Upgrade first (some features may require compat=1.1) */
@@ -2808,6 +2813,27 @@ static int qcow2_amend_options(BlockDriverState *bs,
QemuOpts *opts,
}
}
+ if (s->refcount_bits != refcount_width) {
+ int refcount_order = ffs(refcount_width) - 1;
+ Error *local_error = NULL;
+
+ if (new_version < 3 && refcount_width != 16) {
+ error_report("Different refcount widths than 16 bits require "
+ "compatibility level 1.1 or above (use compat=1.1 or "
+ "greater)");
+ return -EINVAL;
+ }
+
+ helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER;
+ ret = qcow2_change_refcount_order(bs, refcount_order,
+ &qcow2_amend_helper_cb,
+ &helper_cb_info, &local_error);
+ if (ret < 0) {
+ qerror_report_err(local_error);
+ return ret;
+ }
+ }
+
if (backing_file || backing_format) {
ret = qcow2_change_backing_file(bs, backing_file ?: bs->backing_file,
backing_format ?: bs->backing_format);
--
1.9.3
