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Re: [PATCH v2 4/6] parallels: support bitmap extension for read-only mod
From: |
Denis V. Lunev |
Subject: |
Re: [PATCH v2 4/6] parallels: support bitmap extension for read-only mode |
Date: |
Fri, 26 Feb 2021 11:42:04 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 |
On 2/24/21 1:47 PM, Vladimir Sementsov-Ogievskiy wrote:
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> block/parallels.h | 6 +-
> block/parallels-ext.c | 300 ++++++++++++++++++++++++++++++++++++++++++
> block/parallels.c | 18 +++
> block/meson.build | 3 +-
> 4 files changed, 325 insertions(+), 2 deletions(-)
> create mode 100644 block/parallels-ext.c
>
> diff --git a/block/parallels.h b/block/parallels.h
> index 9a9209e320..f22f43f988 100644
> --- a/block/parallels.h
> +++ b/block/parallels.h
> @@ -48,7 +48,8 @@ typedef struct ParallelsHeader {
> uint64_t nb_sectors;
> uint32_t inuse;
> uint32_t data_off;
> - char padding[12];
> + uint32_t flags;
> + uint64_t ext_off;
> } QEMU_PACKED ParallelsHeader;
>
> typedef enum ParallelsPreallocMode {
> @@ -85,4 +86,7 @@ typedef struct BDRVParallelsState {
> Error *migration_blocker;
> } BDRVParallelsState;
>
> +int parallels_read_format_extension(BlockDriverState *bs,
> + int64_t ext_off, Error **errp);
> +
> #endif
> diff --git a/block/parallels-ext.c b/block/parallels-ext.c
> new file mode 100644
> index 0000000000..e0dd0975c6
> --- /dev/null
> +++ b/block/parallels-ext.c
> @@ -0,0 +1,300 @@
> +/*
> + * Support of Parallels Format Extension. It's a part of Parallels format
> + * driver.
> + *
> + * Copyright (c) 2021 Virtuozzo International GmbH
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "block/block_int.h"
> +#include "parallels.h"
> +#include "crypto/hash.h"
> +#include "qemu/uuid.h"
> +
> +#define PARALLELS_FORMAT_EXTENSION_MAGIC 0xAB234CEF23DCEA87ULL
> +
> +#define PARALLELS_END_OF_FEATURES_MAGIC 0x0ULL
> +#define PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC 0x20385FAE252CB34AULL
> +
> +typedef struct ParallelsFormatExtensionHeader {
> + uint64_t magic; /* PARALLELS_FORMAT_EXTENSION_MAGIC */
> + uint8_t check_sum[16];
> +} QEMU_PACKED ParallelsFormatExtensionHeader;
> +
> +typedef struct ParallelsFeatureHeader {
> + uint64_t magic;
> + uint64_t flags;
> + uint32_t data_size;
> + uint32_t _unused;
> +} QEMU_PACKED ParallelsFeatureHeader;
> +
> +typedef struct ParallelsDirtyBitmapFeature {
> + uint64_t size;
> + uint8_t id[16];
> + uint32_t granularity;
> + uint32_t l1_size;
> + /* L1 table follows */
> +} QEMU_PACKED ParallelsDirtyBitmapFeature;
> +
> +/* Given L1 table read bitmap data from the image and populate @bitmap */
> +static int parallels_load_bitmap_data(BlockDriverState *bs,
> + const uint64_t *l1_table,
> + uint32_t l1_size,
> + BdrvDirtyBitmap *bitmap,
> + Error **errp)
> +{
> + BDRVParallelsState *s = bs->opaque;
> + int ret = 0;
> + uint64_t offset, limit;
> + uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
> + uint8_t *buf = NULL;
> + uint64_t i, tab_size =
> + DIV_ROUND_UP(bdrv_dirty_bitmap_serialization_size(bitmap, 0,
> bm_size),
> + s->cluster_size);
> +
> + if (tab_size != l1_size) {
> + error_setg(errp, "Bitmap table size %" PRIu32 " does not correspond "
> + "to bitmap size and cluster size. Expected %" PRIu64,
> + l1_size, tab_size);
> + return -EINVAL;
> + }
> +
> + buf = qemu_blockalign(bs, s->cluster_size);
> + limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size,
> bitmap);
> + for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) {
> + uint64_t count = MIN(bm_size - offset, limit);
> + uint64_t entry = l1_table[i];
> +
> + if (entry == 0) {
> + /* No need to deserialize zeros because @bitmap is cleared. */
> + continue;
> + }
> +
> + if (entry == 1) {
> + bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count, false);
> + } else {
> + ret = bdrv_pread(bs->file, entry << BDRV_SECTOR_BITS, buf,
> + s->cluster_size);
> + if (ret < 0) {
> + error_setg_errno(errp, -ret,
> + "Failed to read bitmap data cluster");
> + goto finish;
> + }
> + bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count,
> + false);
> + }
> + }
> + ret = 0;
> +
> + bdrv_dirty_bitmap_deserialize_finish(bitmap);
> +
> +finish:
> + qemu_vfree(buf);
> +
> + return ret;
> +}
> +
> +/*
> + * @data buffer (of @data_size size) is the Dirty bitmaps feature which
> + * consists of ParallelsDirtyBitmapFeature followed by L1 table.
> + */
> +static BdrvDirtyBitmap *parallels_load_bitmap(BlockDriverState *bs,
> + uint8_t *data,
> + size_t data_size,
> + Error **errp)
> +{
> + int ret;
> + ParallelsDirtyBitmapFeature bf;
> + g_autofree uint64_t *l1_table = NULL;
> + BdrvDirtyBitmap *bitmap;
> + QemuUUID uuid;
> + char uuidstr[UUID_FMT_LEN + 1];
> + int i;
> +
> + if (data_size < sizeof(bf)) {
> + error_setg(errp, "Too small Bitmap Feature area in Parallels Format "
> + "Extension: %zu bytes, expected at least %zu bytes",
> + data_size, sizeof(bf));
> + return NULL;
> + }
> + memcpy(&bf, data, sizeof(bf));
> + bf.size = le64_to_cpu(bf.size);
> + bf.granularity = le32_to_cpu(bf.granularity) << BDRV_SECTOR_BITS;
> + bf.l1_size = le32_to_cpu(bf.l1_size);
> + data += sizeof(bf);
> + data_size -= sizeof(bf);
> +
> + if (bf.size != bs->total_sectors) {
> + error_setg(errp, "Bitmap size (in sectors) %" PRId64 " differs from "
> + "disk size in sectors %" PRId64, bf.size,
> bs->total_sectors);
> + return NULL;
> + }
> +
> + if (bf.l1_size * sizeof(uint64_t) > data_size) {
> + error_setg(errp, "Bitmaps feature corrupted: l1 table exceeds "
> + "extension data_size");
> + return NULL;
> + }
> +
> + memcpy(&uuid, bf.id, sizeof(uuid));
> + qemu_uuid_unparse(&uuid, uuidstr);
> + bitmap = bdrv_create_dirty_bitmap(bs, bf.granularity, uuidstr, errp);
> + if (!bitmap) {
> + return NULL;
> + }
> +
> + l1_table = g_new(uint64_t, bf.l1_size);
> + for (i = 0; i < bf.l1_size; i++, data += sizeof(uint64_t)) {
> + l1_table[i] = ldq_le_p(data);
> + }
> +
> + ret = parallels_load_bitmap_data(bs, l1_table, bf.l1_size, bitmap, errp);
> + if (ret < 0) {
> + bdrv_release_dirty_bitmap(bitmap);
> + return NULL;
> + }
> +
> + /* We support format extension only for RO parallels images. */
> + assert(!(bs->open_flags & BDRV_O_RDWR));
> + bdrv_dirty_bitmap_set_readonly(bitmap, true);
> +
> + return bitmap;
> +}
> +
> +static int parallels_parse_format_extension(BlockDriverState *bs,
> + uint8_t *ext_cluster, Error
> **errp)
> +{
> + BDRVParallelsState *s = bs->opaque;
> + int ret;
> + int remaining = s->cluster_size;
> + uint8_t *pos = ext_cluster;
> + ParallelsFormatExtensionHeader eh;
> + g_autofree uint8_t *hash = NULL;
> + size_t hash_len = 0;
> + GSList *bitmaps = NULL, *el;
> +
> + memcpy(&eh, pos, sizeof(eh));
> + eh.magic = le64_to_cpu(eh.magic);
> + pos += sizeof(eh);
> + remaining -= sizeof(eh);
> +
> + if (eh.magic != PARALLELS_FORMAT_EXTENSION_MAGIC) {
> + error_setg(errp, "Wrong parallels Format Extension magic: 0x%" PRIx64
> + ", expected: 0x%llx", eh.magic,
> + PARALLELS_FORMAT_EXTENSION_MAGIC);
> + goto fail;
> + }
> +
> + ret = qcrypto_hash_bytes(QCRYPTO_HASH_ALG_MD5, (char *)pos, remaining,
> + &hash, &hash_len, errp);
> + if (ret < 0) {
> + goto fail;
> + }
> +
> + if (hash_len != sizeof(eh.check_sum) ||
> + memcmp(hash, eh.check_sum, sizeof(eh.check_sum)) != 0) {
> + error_setg(errp, "Wrong checksum in Format Extension header. Format "
> + "extension is corrupted.");
> + goto fail;
> + }
> +
> + while (true) {
> + ParallelsFeatureHeader fh;
> + BdrvDirtyBitmap *bitmap;
> +
> + if (remaining < sizeof(fh)) {
> + error_setg(errp, "Can not read feature header, as remaining
> bytes "
> + "(%d) in Format Extension is less than Feature header
> "
> + "size (%zu)", remaining, sizeof(fh));
> + goto fail;
> + }
> +
> + memcpy(&fh, pos, sizeof(fh));
> + pos += sizeof(fh);
> + remaining -= sizeof(fh);
> +
> + fh.magic = le64_to_cpu(fh.magic);
> + fh.flags = le64_to_cpu(fh.flags);
> + fh.data_size = le32_to_cpu(fh.data_size);
> +
> + if (fh.flags) {
> + error_setg(errp, "Flags for extension feature are unsupported");
> + goto fail;
> + }
> +
> + if (fh.data_size > remaining) {
> + error_setg(errp, "Feature data_size exceedes Format Extension "
> + "cluster");
> + goto fail;
> + }
> +
> + switch (fh.magic) {
> + case PARALLELS_END_OF_FEATURES_MAGIC:
> + return 0;
> +
> + case PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC:
> + bitmap = parallels_load_bitmap(bs, pos, fh.data_size, errp);
> + if (!bitmap) {
> + goto fail;
> + }
> + bitmaps = g_slist_append(bitmaps, bitmap);
> + break;
> +
> + default:
> + error_setg(errp, "Unknown feature: 0x%" PRIu64, fh.magic);
> + goto fail;
> + }
> +
> + pos = ext_cluster + QEMU_ALIGN_UP(pos + fh.data_size - ext_cluster,
> 8);
> + }
> +
> +fail:
> + for (el = bitmaps; el; el = el->next) {
> + bdrv_release_dirty_bitmap(el->data);
> + }
> + g_slist_free(bitmaps);
> +
> + return -EINVAL;
> +}
> +
> +int parallels_read_format_extension(BlockDriverState *bs,
> + int64_t ext_off, Error **errp)
> +{
> + BDRVParallelsState *s = bs->opaque;
> + int ret;
> + uint8_t *ext_cluster = qemu_blockalign(bs, s->cluster_size);
> +
> + assert(ext_off > 0);
> +
> + ret = bdrv_pread(bs->file, ext_off, ext_cluster, s->cluster_size);
> + if (ret < 0) {
> + error_setg_errno(errp, -ret, "Failed to read Format Extension
> cluster");
> + goto out;
> + }
> +
> + ret = parallels_parse_format_extension(bs, ext_cluster, errp);
> +
> +out:
> + qemu_vfree(ext_cluster);
> +
> + return ret;
> +}
> diff --git a/block/parallels.c b/block/parallels.c
> index 9594d84978..6ebad2a2bb 100644
> --- a/block/parallels.c
> +++ b/block/parallels.c
> @@ -29,6 +29,7 @@
> */
>
> #include "qemu/osdep.h"
> +#include "qemu/error-report.h"
> #include "qapi/error.h"
> #include "block/block_int.h"
> #include "block/qdict.h"
> @@ -843,6 +844,23 @@ static int parallels_open(BlockDriverState *bs, QDict
> *options, int flags,
> goto fail_options;
> }
>
> + if (ph.ext_off) {
> + if (flags & BDRV_O_RDWR) {
> + /*
> + * It's unsafe to open image RW if there is an extension (as we
> + * don't support it). But parallels driver in QEMU historically
> + * ignores the extension, so print warning and don't care.
> + */
> + warn_report("Format Extension ignored in RW mode");
> + } else {
> + ret = parallels_read_format_extension(
> + bs, le64_to_cpu(ph.ext_off) << BDRV_SECTOR_BITS, errp);
> + if (ret < 0) {
> + goto fail;
> + }
> + }
> + }
> +
> if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_INACTIVE)) {
> s->header->inuse = cpu_to_le32(HEADER_INUSE_MAGIC);
> ret = parallels_update_header(bs);
> diff --git a/block/meson.build b/block/meson.build
> index eeaefe5809..d21990ec95 100644
> --- a/block/meson.build
> +++ b/block/meson.build
> @@ -57,7 +57,8 @@ block_ss.add(when: 'CONFIG_QED', if_true: files(
> 'qed-table.c',
> 'qed.c',
> ))
> -block_ss.add(when: [libxml2, 'CONFIG_PARALLELS'], if_true:
> files('parallels.c'))
> +block_ss.add(when: [libxml2, 'CONFIG_PARALLELS'],
> + if_true: files('parallels.c', 'parallels-ext.c'))
> block_ss.add(when: 'CONFIG_WIN32', if_true: files('file-win32.c',
> 'win32-aio.c'))
> block_ss.add(when: 'CONFIG_POSIX', if_true: [files('file-posix.c'), coref,
> iokit])
> block_ss.add(when: libiscsi, if_true: files('iscsi-opts.c'))
Reviewed-by: Denis V. Lunev <den@openvz.org>
- [PATCH v2 0/6] parallels: load bitmap extension, Vladimir Sementsov-Ogievskiy, 2021/02/24
- [PATCH v2 1/6] qcow2-bitmap: make bytes_covered_by_bitmap_cluster() public, Vladimir Sementsov-Ogievskiy, 2021/02/24
- [PATCH v2 2/6] parallels.txt: fix bitmap L1 table description, Vladimir Sementsov-Ogievskiy, 2021/02/24
- [PATCH v2 3/6] block/parallels: BDRVParallelsState: add cluster_size field, Vladimir Sementsov-Ogievskiy, 2021/02/24
- [PATCH v2 4/6] parallels: support bitmap extension for read-only mode, Vladimir Sementsov-Ogievskiy, 2021/02/24
- Re: [PATCH v2 4/6] parallels: support bitmap extension for read-only mode,
Denis V. Lunev <=
- [PATCH v2 5/6] iotests.py: add unarchive_sample_image() helper, Vladimir Sementsov-Ogievskiy, 2021/02/24
- [PATCH v2 6/6] iotests: add parallels-read-bitmap test, Vladimir Sementsov-Ogievskiy, 2021/02/24