Dario Faggioli
3206ea7c01
- Revert to revision 715. We're fixing bug 1199924, before moving to QEMU 7.0 OBS-URL: https://build.opensuse.org/request/show/979479 OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=718
109 lines
3.6 KiB
Diff
109 lines
3.6 KiB
Diff
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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Date: Thu, 23 Dec 2021 17:01:37 +0100
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Subject: qcow2: simple case support for downgrading of qcow2 images with zstd
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Git-commit: 083c24561a1f52829b5b31a0fb2f7c77efb979c0
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If image doesn't have any compressed cluster we can easily switch to
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zlib compression, which may allow to downgrade the image.
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That's mostly needed to support IMGOPTS='compression_type=zstd' in some
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iotests which do qcow2 downgrade.
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While being here also fix checkpatch complain against '#' in printf
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formatting.
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Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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Reviewed-by: Max Reitz <mreitz@redhat.com>
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Message-Id: <20211223160144.1097696-13-vsementsov@virtuozzo.com>
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Signed-off-by: Hanna Reitz <hreitz@redhat.com>
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Signed-off-by: Li Zhang <lizhang@suse.de>
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---
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block/qcow2.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++--
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1 file changed, 56 insertions(+), 2 deletions(-)
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diff --git a/block/qcow2.c b/block/qcow2.c
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index d50901675699ef3806bacb780ee0..c8115e1cba0f8ed09254f7889d38 100644
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--- a/block/qcow2.c
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+++ b/block/qcow2.c
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@@ -5279,6 +5279,38 @@ static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
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return bs->drv->bdrv_co_preadv_part(bs, offset, qiov->size, qiov, 0, 0);
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}
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+static int qcow2_has_compressed_clusters(BlockDriverState *bs)
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+{
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+ int64_t offset = 0;
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+ int64_t bytes = bdrv_getlength(bs);
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+
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+ if (bytes < 0) {
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+ return bytes;
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+ }
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+
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+ while (bytes != 0) {
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+ int ret;
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+ QCow2SubclusterType type;
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+ unsigned int cur_bytes = MIN(INT_MAX, bytes);
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+ uint64_t host_offset;
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+
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+ ret = qcow2_get_host_offset(bs, offset, &cur_bytes, &host_offset,
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+ &type);
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+ if (ret < 0) {
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+ return ret;
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+ }
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+
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+ if (type == QCOW2_SUBCLUSTER_COMPRESSED) {
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+ return 1;
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+ }
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+
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+ offset += cur_bytes;
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+ bytes -= cur_bytes;
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+ }
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+
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+ return 0;
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+}
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+
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/*
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* Downgrades an image's version. To achieve this, any incompatible features
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* have to be removed.
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@@ -5336,9 +5368,10 @@ static int qcow2_downgrade(BlockDriverState *bs, int target_version,
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* the first place; if that happens nonetheless, returning -ENOTSUP is the
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* best thing to do anyway */
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- if (s->incompatible_features) {
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+ if (s->incompatible_features & ~QCOW2_INCOMPAT_COMPRESSION) {
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error_setg(errp, "Cannot downgrade an image with incompatible features "
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- "%#" PRIx64 " set", s->incompatible_features);
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+ "0x%" PRIx64 " set",
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+ s->incompatible_features & ~QCOW2_INCOMPAT_COMPRESSION);
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return -ENOTSUP;
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}
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@@ -5356,6 +5389,27 @@ static int qcow2_downgrade(BlockDriverState *bs, int target_version,
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return ret;
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}
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+ if (s->incompatible_features & QCOW2_INCOMPAT_COMPRESSION) {
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+ ret = qcow2_has_compressed_clusters(bs);
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+ if (ret < 0) {
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+ error_setg(errp, "Failed to check block status");
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+ return -EINVAL;
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+ }
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+ if (ret) {
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+ error_setg(errp, "Cannot downgrade an image with zstd compression "
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+ "type and existing compressed clusters");
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+ return -ENOTSUP;
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+ }
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+ /*
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+ * No compressed clusters for now, so just chose default zlib
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+ * compression.
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+ */
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+ s->incompatible_features &= ~QCOW2_INCOMPAT_COMPRESSION;
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+ s->compression_type = QCOW2_COMPRESSION_TYPE_ZLIB;
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+ }
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+
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+ assert(s->incompatible_features == 0);
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+
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s->qcow_version = target_version;
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ret = qcow2_update_header(bs);
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if (ret < 0) {
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