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qemu-e2k/block/qcow2.c
Andrey Shinkevich 170d3bd341 block: include base when checking image chain for block allocation 
This patch is used in the 'block/stream: introduce a bottom node'
that is following. Instead of the base node, the caller may pass
the node that has the base as its backing image to the function
bdrv_is_allocated_above() with a new parameter include_base = true
and get rid of the dependency on the base that may change during
commit/stream parallel jobs. Now, if the specified base is not
found in the backing image chain, the QEMU will abort.

Suggested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 1559152576-281803-2-git-send-email-andrey.shinkevich@virtuozzo.com
[mreitz: Squashed in the following as a rebase on conflicting patches:]
Message-id: e3cf99ae-62e9-8b6e-5a06-d3c8b9363b85@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-07-02 03:53:04 +02:00

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/*
* Block driver for the QCOW version 2 format
*
* Copyright (c) 2004-2006 Fabrice Bellard
*
* 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 "block/qdict.h"
#include "sysemu/block-backend.h"
#include "qemu/module.h"
#include "qcow2.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "qapi/qapi-events-block-core.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
#include "trace.h"
#include "qemu/option_int.h"
#include "qemu/cutils.h"
#include "qemu/bswap.h"
#include "qapi/qobject-input-visitor.h"
#include "qapi/qapi-visit-block-core.h"
#include "crypto.h"
/*
Differences with QCOW:
- Support for multiple incremental snapshots.
- Memory management by reference counts.
- Clusters which have a reference count of one have the bit
QCOW_OFLAG_COPIED to optimize write performance.
- Size of compressed clusters is stored in sectors to reduce bit usage
in the cluster offsets.
- Support for storing additional data (such as the VM state) in the
snapshots.
- If a backing store is used, the cluster size is not constrained
(could be backported to QCOW).
- L2 tables have always a size of one cluster.
*/
typedef struct {
uint32_t magic;
uint32_t len;
} QEMU_PACKED QCowExtension;
#define QCOW2_EXT_MAGIC_END 0
#define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
#define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
#define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77
#define QCOW2_EXT_MAGIC_BITMAPS 0x23852875
#define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441
static int coroutine_fn
qcow2_co_preadv_compressed(BlockDriverState *bs,
uint64_t file_cluster_offset,
uint64_t offset,
uint64_t bytes,
QEMUIOVector *qiov);
static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
{
const QCowHeader *cow_header = (const void *)buf;
if (buf_size >= sizeof(QCowHeader) &&
be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
be32_to_cpu(cow_header->version) >= 2)
return 100;
else
return 0;
}
static ssize_t qcow2_crypto_hdr_read_func(QCryptoBlock *block, size_t offset,
uint8_t *buf, size_t buflen,
void *opaque, Error **errp)
{
BlockDriverState *bs = opaque;
BDRVQcow2State *s = bs->opaque;
ssize_t ret;
if ((offset + buflen) > s->crypto_header.length) {
error_setg(errp, "Request for data outside of extension header");
return -1;
}
ret = bdrv_pread(bs->file,
s->crypto_header.offset + offset, buf, buflen);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read encryption header");
return -1;
}
return ret;
}
static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen,
void *opaque, Error **errp)
{
BlockDriverState *bs = opaque;
BDRVQcow2State *s = bs->opaque;
int64_t ret;
int64_t clusterlen;
ret = qcow2_alloc_clusters(bs, headerlen);
if (ret < 0) {
error_setg_errno(errp, -ret,
"Cannot allocate cluster for LUKS header size %zu",
headerlen);
return -1;
}
s->crypto_header.length = headerlen;
s->crypto_header.offset = ret;
/* Zero fill remaining space in cluster so it has predictable
* content in case of future spec changes */
clusterlen = size_to_clusters(s, headerlen) * s->cluster_size;
assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0);
ret = bdrv_pwrite_zeroes(bs->file,
ret + headerlen,
clusterlen - headerlen, 0);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not zero fill encryption header");
return -1;
}
return ret;
}
static ssize_t qcow2_crypto_hdr_write_func(QCryptoBlock *block, size_t offset,
const uint8_t *buf, size_t buflen,
void *opaque, Error **errp)
{
BlockDriverState *bs = opaque;
BDRVQcow2State *s = bs->opaque;
ssize_t ret;
if ((offset + buflen) > s->crypto_header.length) {
error_setg(errp, "Request for data outside of extension header");
return -1;
}
ret = bdrv_pwrite(bs->file,
s->crypto_header.offset + offset, buf, buflen);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read encryption header");
return -1;
}
return ret;
}
/*
* read qcow2 extension and fill bs
* start reading from start_offset
* finish reading upon magic of value 0 or when end_offset reached
* unknown magic is skipped (future extension this version knows nothing about)
* return 0 upon success, non-0 otherwise
*/
static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
uint64_t end_offset, void **p_feature_table,
int flags, bool *need_update_header,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
QCowExtension ext;
uint64_t offset;
int ret;
Qcow2BitmapHeaderExt bitmaps_ext;
if (need_update_header != NULL) {
*need_update_header = false;
}
#ifdef DEBUG_EXT
printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
#endif
offset = start_offset;
while (offset < end_offset) {
#ifdef DEBUG_EXT
/* Sanity check */
if (offset > s->cluster_size)
printf("qcow2_read_extension: suspicious offset %lu\n", offset);
printf("attempting to read extended header in offset %lu\n", offset);
#endif
ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext));
if (ret < 0) {
error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: "
"pread fail from offset %" PRIu64, offset);
return 1;
}
ext.magic = be32_to_cpu(ext.magic);
ext.len = be32_to_cpu(ext.len);
offset += sizeof(ext);
#ifdef DEBUG_EXT
printf("ext.magic = 0x%x\n", ext.magic);
#endif
if (offset > end_offset || ext.len > end_offset - offset) {
error_setg(errp, "Header extension too large");
return -EINVAL;
}
switch (ext.magic) {
case QCOW2_EXT_MAGIC_END:
return 0;
case QCOW2_EXT_MAGIC_BACKING_FORMAT:
if (ext.len >= sizeof(bs->backing_format)) {
error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32
" too large (>=%zu)", ext.len,
sizeof(bs->backing_format));
return 2;
}
ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len);
if (ret < 0) {
error_setg_errno(errp, -ret, "ERROR: ext_backing_format: "
"Could not read format name");
return 3;
}
bs->backing_format[ext.len] = '\0';
s->image_backing_format = g_strdup(bs->backing_format);
#ifdef DEBUG_EXT
printf("Qcow2: Got format extension %s\n", bs->backing_format);
#endif
break;
case QCOW2_EXT_MAGIC_FEATURE_TABLE:
if (p_feature_table != NULL) {
void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature));
ret = bdrv_pread(bs->file, offset , feature_table, ext.len);
if (ret < 0) {
error_setg_errno(errp, -ret, "ERROR: ext_feature_table: "
"Could not read table");
return ret;
}
*p_feature_table = feature_table;
}
break;
case QCOW2_EXT_MAGIC_CRYPTO_HEADER: {
unsigned int cflags = 0;
if (s->crypt_method_header != QCOW_CRYPT_LUKS) {
error_setg(errp, "CRYPTO header extension only "
"expected with LUKS encryption method");
return -EINVAL;
}
if (ext.len != sizeof(Qcow2CryptoHeaderExtension)) {
error_setg(errp, "CRYPTO header extension size %u, "
"but expected size %zu", ext.len,
sizeof(Qcow2CryptoHeaderExtension));
return -EINVAL;
}
ret = bdrv_pread(bs->file, offset, &s->crypto_header, ext.len);
if (ret < 0) {
error_setg_errno(errp, -ret,
"Unable to read CRYPTO header extension");
return ret;
}
s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset);
s->crypto_header.length = be64_to_cpu(s->crypto_header.length);
if ((s->crypto_header.offset % s->cluster_size) != 0) {
error_setg(errp, "Encryption header offset '%" PRIu64 "' is "
"not a multiple of cluster size '%u'",
s->crypto_header.offset, s->cluster_size);
return -EINVAL;
}
if (flags & BDRV_O_NO_IO) {
cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
}
s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.",
qcow2_crypto_hdr_read_func,
bs, cflags, QCOW2_MAX_THREADS, errp);
if (!s->crypto) {
return -EINVAL;
}
} break;
case QCOW2_EXT_MAGIC_BITMAPS:
if (ext.len != sizeof(bitmaps_ext)) {
error_setg_errno(errp, -ret, "bitmaps_ext: "
"Invalid extension length");
return -EINVAL;
}
if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) {
if (s->qcow_version < 3) {
/* Let's be a bit more specific */
warn_report("This qcow2 v2 image contains bitmaps, but "
"they may have been modified by a program "
"without persistent bitmap support; so now "
"they must all be considered inconsistent");
} else {
warn_report("a program lacking bitmap support "
"modified this file, so all bitmaps are now "
"considered inconsistent");
}
error_printf("Some clusters may be leaked, "
"run 'qemu-img check -r' on the image "
"file to fix.");
if (need_update_header != NULL) {
/* Updating is needed to drop invalid bitmap extension. */
*need_update_header = true;
}
break;
}
ret = bdrv_pread(bs->file, offset, &bitmaps_ext, ext.len);
if (ret < 0) {
error_setg_errno(errp, -ret, "bitmaps_ext: "
"Could not read ext header");
return ret;
}
if (bitmaps_ext.reserved32 != 0) {
error_setg_errno(errp, -ret, "bitmaps_ext: "
"Reserved field is not zero");
return -EINVAL;
}
bitmaps_ext.nb_bitmaps = be32_to_cpu(bitmaps_ext.nb_bitmaps);
bitmaps_ext.bitmap_directory_size =
be64_to_cpu(bitmaps_ext.bitmap_directory_size);
bitmaps_ext.bitmap_directory_offset =
be64_to_cpu(bitmaps_ext.bitmap_directory_offset);
if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) {
error_setg(errp,
"bitmaps_ext: Image has %" PRIu32 " bitmaps, "
"exceeding the QEMU supported maximum of %d",
bitmaps_ext.nb_bitmaps, QCOW2_MAX_BITMAPS);
return -EINVAL;
}
if (bitmaps_ext.nb_bitmaps == 0) {
error_setg(errp, "found bitmaps extension with zero bitmaps");
return -EINVAL;
}
if (bitmaps_ext.bitmap_directory_offset & (s->cluster_size - 1)) {
error_setg(errp, "bitmaps_ext: "
"invalid bitmap directory offset");
return -EINVAL;
}
if (bitmaps_ext.bitmap_directory_size >
QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
error_setg(errp, "bitmaps_ext: "
"bitmap directory size (%" PRIu64 ") exceeds "
"the maximum supported size (%d)",
bitmaps_ext.bitmap_directory_size,
QCOW2_MAX_BITMAP_DIRECTORY_SIZE);
return -EINVAL;
}
s->nb_bitmaps = bitmaps_ext.nb_bitmaps;
s->bitmap_directory_offset =
bitmaps_ext.bitmap_directory_offset;
s->bitmap_directory_size =
bitmaps_ext.bitmap_directory_size;
#ifdef DEBUG_EXT
printf("Qcow2: Got bitmaps extension: "
"offset=%" PRIu64 " nb_bitmaps=%" PRIu32 "\n",
s->bitmap_directory_offset, s->nb_bitmaps);
#endif
break;
case QCOW2_EXT_MAGIC_DATA_FILE:
{
s->image_data_file = g_malloc0(ext.len + 1);
ret = bdrv_pread(bs->file, offset, s->image_data_file, ext.len);
if (ret < 0) {
error_setg_errno(errp, -ret,
"ERROR: Could not read data file name");
return ret;
}
#ifdef DEBUG_EXT
printf("Qcow2: Got external data file %s\n", s->image_data_file);
#endif
break;
}
default:
/* unknown magic - save it in case we need to rewrite the header */
/* If you add a new feature, make sure to also update the fast
* path of qcow2_make_empty() to deal with it. */
{
Qcow2UnknownHeaderExtension *uext;
uext = g_malloc0(sizeof(*uext) + ext.len);
uext->magic = ext.magic;
uext->len = ext.len;
QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next);
ret = bdrv_pread(bs->file, offset , uext->data, uext->len);
if (ret < 0) {
error_setg_errno(errp, -ret, "ERROR: unknown extension: "
"Could not read data");
return ret;
}
}
break;
}
offset += ((ext.len + 7) & ~7);
}
return 0;
}
static void cleanup_unknown_header_ext(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
Qcow2UnknownHeaderExtension *uext, *next;
QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) {
QLIST_REMOVE(uext, next);
g_free(uext);
}
}
static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
uint64_t mask)
{
char *features = g_strdup("");
char *old;
while (table && table->name[0] != '\0') {
if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
if (mask & (1ULL << table->bit)) {
old = features;
features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "",
table->name);
g_free(old);
mask &= ~(1ULL << table->bit);
}
}
table++;
}
if (mask) {
old = features;
features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64,
old, *old ? ", " : "", mask);
g_free(old);
}
error_setg(errp, "Unsupported qcow2 feature(s): %s", features);
g_free(features);
}
/*
* Sets the dirty bit and flushes afterwards if necessary.
*
* The incompatible_features bit is only set if the image file header was
* updated successfully. Therefore it is not required to check the return
* value of this function.
*/
int qcow2_mark_dirty(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
uint64_t val;
int ret;
assert(s->qcow_version >= 3);
if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
return 0; /* already dirty */
}
val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY);
ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features),
&val, sizeof(val));
if (ret < 0) {
return ret;
}
ret = bdrv_flush(bs->file->bs);
if (ret < 0) {
return ret;
}
/* Only treat image as dirty if the header was updated successfully */
s->incompatible_features |= QCOW2_INCOMPAT_DIRTY;
return 0;
}
/*
* Clears the dirty bit and flushes before if necessary. Only call this
* function when there are no pending requests, it does not guard against
* concurrent requests dirtying the image.
*/
static int qcow2_mark_clean(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
int ret;
s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY;
ret = qcow2_flush_caches(bs);
if (ret < 0) {
return ret;
}
return qcow2_update_header(bs);
}
return 0;
}
/*
* Marks the image as corrupt.
*/
int qcow2_mark_corrupt(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT;
return qcow2_update_header(bs);
}
/*
* Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
* before if necessary.
*/
int qcow2_mark_consistent(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
int ret = qcow2_flush_caches(bs);
if (ret < 0) {
return ret;
}
s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT;
return qcow2_update_header(bs);
}
return 0;
}
static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs,
BdrvCheckResult *result,
BdrvCheckMode fix)
{
int ret = qcow2_check_refcounts(bs, result, fix);
if (ret < 0) {
return ret;
}
if (fix && result->check_errors == 0 && result->corruptions == 0) {
ret = qcow2_mark_clean(bs);
if (ret < 0) {
return ret;
}
return qcow2_mark_consistent(bs);
}
return ret;
}
static int coroutine_fn qcow2_co_check(BlockDriverState *bs,
BdrvCheckResult *result,
BdrvCheckMode fix)
{
BDRVQcow2State *s = bs->opaque;
int ret;
qemu_co_mutex_lock(&s->lock);
ret = qcow2_co_check_locked(bs, result, fix);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
uint64_t entries, size_t entry_len,
int64_t max_size_bytes, const char *table_name,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
if (entries > max_size_bytes / entry_len) {
error_setg(errp, "%s too large", table_name);
return -EFBIG;
}
/* Use signed INT64_MAX as the maximum even for uint64_t header fields,
* because values will be passed to qemu functions taking int64_t. */
if ((INT64_MAX - entries * entry_len < offset) ||
(offset_into_cluster(s, offset) != 0)) {
error_setg(errp, "%s offset invalid", table_name);
return -EINVAL;
}
return 0;
}
static const char *const mutable_opts[] = {
QCOW2_OPT_LAZY_REFCOUNTS,
QCOW2_OPT_DISCARD_REQUEST,
QCOW2_OPT_DISCARD_SNAPSHOT,
QCOW2_OPT_DISCARD_OTHER,
QCOW2_OPT_OVERLAP,
QCOW2_OPT_OVERLAP_TEMPLATE,
QCOW2_OPT_OVERLAP_MAIN_HEADER,
QCOW2_OPT_OVERLAP_ACTIVE_L1,
QCOW2_OPT_OVERLAP_ACTIVE_L2,
QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
QCOW2_OPT_OVERLAP_INACTIVE_L1,
QCOW2_OPT_OVERLAP_INACTIVE_L2,
QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY,
QCOW2_OPT_CACHE_SIZE,
QCOW2_OPT_L2_CACHE_SIZE,
QCOW2_OPT_L2_CACHE_ENTRY_SIZE,
QCOW2_OPT_REFCOUNT_CACHE_SIZE,
QCOW2_OPT_CACHE_CLEAN_INTERVAL,
NULL
};
static QemuOptsList qcow2_runtime_opts = {
.name = "qcow2",
.head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
.desc = {
{
.name = QCOW2_OPT_LAZY_REFCOUNTS,
.type = QEMU_OPT_BOOL,
.help = "Postpone refcount updates",
},
{
.name = QCOW2_OPT_DISCARD_REQUEST,
.type = QEMU_OPT_BOOL,
.help = "Pass guest discard requests to the layer below",
},
{
.name = QCOW2_OPT_DISCARD_SNAPSHOT,
.type = QEMU_OPT_BOOL,
.help = "Generate discard requests when snapshot related space "
"is freed",
},
{
.name = QCOW2_OPT_DISCARD_OTHER,
.type = QEMU_OPT_BOOL,
.help = "Generate discard requests when other clusters are freed",
},
{
.name = QCOW2_OPT_OVERLAP,
.type = QEMU_OPT_STRING,
.help = "Selects which overlap checks to perform from a range of "
"templates (none, constant, cached, all)",
},
{
.name = QCOW2_OPT_OVERLAP_TEMPLATE,
.type = QEMU_OPT_STRING,
.help = "Selects which overlap checks to perform from a range of "
"templates (none, constant, cached, all)",
},
{
.name = QCOW2_OPT_OVERLAP_MAIN_HEADER,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into the main qcow2 header",
},
{
.name = QCOW2_OPT_OVERLAP_ACTIVE_L1,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into the active L1 table",
},
{
.name = QCOW2_OPT_OVERLAP_ACTIVE_L2,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into an active L2 table",
},
{
.name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into the refcount table",
},
{
.name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into a refcount block",
},
{
.name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into the snapshot table",
},
{
.name = QCOW2_OPT_OVERLAP_INACTIVE_L1,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into an inactive L1 table",
},
{
.name = QCOW2_OPT_OVERLAP_INACTIVE_L2,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into an inactive L2 table",
},
{
.name = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY,
.type = QEMU_OPT_BOOL,
.help = "Check for unintended writes into the bitmap directory",
},
{
.name = QCOW2_OPT_CACHE_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Maximum combined metadata (L2 tables and refcount blocks) "
"cache size",
},
{
.name = QCOW2_OPT_L2_CACHE_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Maximum L2 table cache size",
},
{
.name = QCOW2_OPT_L2_CACHE_ENTRY_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Size of each entry in the L2 cache",
},
{
.name = QCOW2_OPT_REFCOUNT_CACHE_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Maximum refcount block cache size",
},
{
.name = QCOW2_OPT_CACHE_CLEAN_INTERVAL,
.type = QEMU_OPT_NUMBER,
.help = "Clean unused cache entries after this time (in seconds)",
},
BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.",
"ID of secret providing qcow2 AES key or LUKS passphrase"),
{ /* end of list */ }
},
};
static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = {
[QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER,
[QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1,
[QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2,
[QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
[QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
[QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
[QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1,
[QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2,
[QCOW2_OL_BITMAP_DIRECTORY_BITNR] = QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY,
};
static void cache_clean_timer_cb(void *opaque)
{
BlockDriverState *bs = opaque;
BDRVQcow2State *s = bs->opaque;
qcow2_cache_clean_unused(s->l2_table_cache);
qcow2_cache_clean_unused(s->refcount_block_cache);
timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
(int64_t) s->cache_clean_interval * 1000);
}
static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context)
{
BDRVQcow2State *s = bs->opaque;
if (s->cache_clean_interval > 0) {
s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL,
SCALE_MS, cache_clean_timer_cb,
bs);
timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
(int64_t) s->cache_clean_interval * 1000);
}
}
static void cache_clean_timer_del(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
if (s->cache_clean_timer) {
timer_del(s->cache_clean_timer);
timer_free(s->cache_clean_timer);
s->cache_clean_timer = NULL;
}
}
static void qcow2_detach_aio_context(BlockDriverState *bs)
{
cache_clean_timer_del(bs);
}
static void qcow2_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
cache_clean_timer_init(bs, new_context);
}
static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
uint64_t *l2_cache_size,
uint64_t *l2_cache_entry_size,
uint64_t *refcount_cache_size, Error **errp)
{
BDRVQcow2State *s = bs->opaque;
uint64_t combined_cache_size, l2_cache_max_setting;
bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set;
bool l2_cache_entry_size_set;
int min_refcount_cache = MIN_REFCOUNT_CACHE_SIZE * s->cluster_size;
uint64_t virtual_disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
uint64_t max_l2_cache = virtual_disk_size / (s->cluster_size / 8);
combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE);
l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE);
refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
l2_cache_entry_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE);
combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0);
l2_cache_max_setting = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE,
DEFAULT_L2_CACHE_MAX_SIZE);
*refcount_cache_size = qemu_opt_get_size(opts,
QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0);
*l2_cache_entry_size = qemu_opt_get_size(
opts, QCOW2_OPT_L2_CACHE_ENTRY_SIZE, s->cluster_size);
*l2_cache_size = MIN(max_l2_cache, l2_cache_max_setting);
if (combined_cache_size_set) {
if (l2_cache_size_set && refcount_cache_size_set) {
error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE
" and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set "
"at the same time");
return;
} else if (l2_cache_size_set &&
(l2_cache_max_setting > combined_cache_size)) {
error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed "
QCOW2_OPT_CACHE_SIZE);
return;
} else if (*refcount_cache_size > combined_cache_size) {
error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed "
QCOW2_OPT_CACHE_SIZE);
return;
}
if (l2_cache_size_set) {
*refcount_cache_size = combined_cache_size - *l2_cache_size;
} else if (refcount_cache_size_set) {
*l2_cache_size = combined_cache_size - *refcount_cache_size;
} else {
/* Assign as much memory as possible to the L2 cache, and
* use the remainder for the refcount cache */
if (combined_cache_size >= max_l2_cache + min_refcount_cache) {
*l2_cache_size = max_l2_cache;
*refcount_cache_size = combined_cache_size - *l2_cache_size;
} else {
*refcount_cache_size =
MIN(combined_cache_size, min_refcount_cache);
*l2_cache_size = combined_cache_size - *refcount_cache_size;
}
}
}
/*
* If the L2 cache is not enough to cover the whole disk then
* default to 4KB entries. Smaller entries reduce the cost of
* loads and evictions and increase I/O performance.
*/
if (*l2_cache_size < max_l2_cache && !l2_cache_entry_size_set) {
*l2_cache_entry_size = MIN(s->cluster_size, 4096);
}
/* l2_cache_size and refcount_cache_size are ensured to have at least
* their minimum values in qcow2_update_options_prepare() */
if (*l2_cache_entry_size < (1 << MIN_CLUSTER_BITS) ||
*l2_cache_entry_size > s->cluster_size ||
!is_power_of_2(*l2_cache_entry_size)) {
error_setg(errp, "L2 cache entry size must be a power of two "
"between %d and the cluster size (%d)",
1 << MIN_CLUSTER_BITS, s->cluster_size);
return;
}
}
typedef struct Qcow2ReopenState {
Qcow2Cache *l2_table_cache;
Qcow2Cache *refcount_block_cache;
int l2_slice_size; /* Number of entries in a slice of the L2 table */
bool use_lazy_refcounts;
int overlap_check;
bool discard_passthrough[QCOW2_DISCARD_MAX];
uint64_t cache_clean_interval;
QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */
} Qcow2ReopenState;
static int qcow2_update_options_prepare(BlockDriverState *bs,
Qcow2ReopenState *r,
QDict *options, int flags,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
QemuOpts *opts = NULL;
const char *opt_overlap_check, *opt_overlap_check_template;
int overlap_check_template = 0;
uint64_t l2_cache_size, l2_cache_entry_size, refcount_cache_size;
int i;
const char *encryptfmt;
QDict *encryptopts = NULL;
Error *local_err = NULL;
int ret;
qdict_extract_subqdict(options, &encryptopts, "encrypt.");
encryptfmt = qdict_get_try_str(encryptopts, "format");
opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
/* get L2 table/refcount block cache size from command line options */
read_cache_sizes(bs, opts, &l2_cache_size, &l2_cache_entry_size,
&refcount_cache_size, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
l2_cache_size /= l2_cache_entry_size;
if (l2_cache_size < MIN_L2_CACHE_SIZE) {
l2_cache_size = MIN_L2_CACHE_SIZE;
}
if (l2_cache_size > INT_MAX) {
error_setg(errp, "L2 cache size too big");
ret = -EINVAL;
goto fail;
}
refcount_cache_size /= s->cluster_size;
if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) {
refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE;
}
if (refcount_cache_size > INT_MAX) {
error_setg(errp, "Refcount cache size too big");
ret = -EINVAL;
goto fail;
}
/* alloc new L2 table/refcount block cache, flush old one */
if (s->l2_table_cache) {
ret = qcow2_cache_flush(bs, s->l2_table_cache);
if (ret) {
error_setg_errno(errp, -ret, "Failed to flush the L2 table cache");
goto fail;
}
}
if (s->refcount_block_cache) {
ret = qcow2_cache_flush(bs, s->refcount_block_cache);
if (ret) {
error_setg_errno(errp, -ret,
"Failed to flush the refcount block cache");
goto fail;
}
}
r->l2_slice_size = l2_cache_entry_size / sizeof(uint64_t);
r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size,
l2_cache_entry_size);
r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size,
s->cluster_size);
if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) {
error_setg(errp, "Could not allocate metadata caches");
ret = -ENOMEM;
goto fail;
}
/* New interval for cache cleanup timer */
r->cache_clean_interval =
qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL,
DEFAULT_CACHE_CLEAN_INTERVAL);
#ifndef CONFIG_LINUX
if (r->cache_clean_interval != 0) {
error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL
" not supported on this host");
ret = -EINVAL;
goto fail;
}
#endif
if (r->cache_clean_interval > UINT_MAX) {
error_setg(errp, "Cache clean interval too big");
ret = -EINVAL;
goto fail;
}
/* lazy-refcounts; flush if going from enabled to disabled */
r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
(s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
if (r->use_lazy_refcounts && s->qcow_version < 3) {
error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
"qemu 1.1 compatibility level");
ret = -EINVAL;
goto fail;
}
if (s->use_lazy_refcounts && !r->use_lazy_refcounts) {
ret = qcow2_mark_clean(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to disable lazy refcounts");
goto fail;
}
}
/* Overlap check options */
opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP);
opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE);
if (opt_overlap_check_template && opt_overlap_check &&
strcmp(opt_overlap_check_template, opt_overlap_check))
{
error_setg(errp, "Conflicting values for qcow2 options '"
QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
"' ('%s')", opt_overlap_check, opt_overlap_check_template);
ret = -EINVAL;
goto fail;
}
if (!opt_overlap_check) {
opt_overlap_check = opt_overlap_check_template ?: "cached";
}
if (!strcmp(opt_overlap_check, "none")) {
overlap_check_template = 0;
} else if (!strcmp(opt_overlap_check, "constant")) {
overlap_check_template = QCOW2_OL_CONSTANT;
} else if (!strcmp(opt_overlap_check, "cached")) {
overlap_check_template = QCOW2_OL_CACHED;
} else if (!strcmp(opt_overlap_check, "all")) {
overlap_check_template = QCOW2_OL_ALL;
} else {
error_setg(errp, "Unsupported value '%s' for qcow2 option "
"'overlap-check'. Allowed are any of the following: "
"none, constant, cached, all", opt_overlap_check);
ret = -EINVAL;
goto fail;
}
r->overlap_check = 0;
for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
/* overlap-check defines a template bitmask, but every flag may be
* overwritten through the associated boolean option */
r->overlap_check |=
qemu_opt_get_bool(opts, overlap_bool_option_names[i],
overlap_check_template & (1 << i)) << i;
}
r->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
r->discard_passthrough[QCOW2_DISCARD_REQUEST] =
qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
flags & BDRV_O_UNMAP);
r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
r->discard_passthrough[QCOW2_DISCARD_OTHER] =
qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
switch (s->crypt_method_header) {
case QCOW_CRYPT_NONE:
if (encryptfmt) {
error_setg(errp, "No encryption in image header, but options "
"specified format '%s'", encryptfmt);
ret = -EINVAL;
goto fail;
}
break;
case QCOW_CRYPT_AES:
if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
error_setg(errp,
"Header reported 'aes' encryption format but "
"options specify '%s'", encryptfmt);
ret = -EINVAL;
goto fail;
}
qdict_put_str(encryptopts, "format", "qcow");
r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
break;
case QCOW_CRYPT_LUKS:
if (encryptfmt && !g_str_equal(encryptfmt, "luks")) {
error_setg(errp,
"Header reported 'luks' encryption format but "
"options specify '%s'", encryptfmt);
ret = -EINVAL;
goto fail;
}
qdict_put_str(encryptopts, "format", "luks");
r->crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
break;
default:
error_setg(errp, "Unsupported encryption method %d",
s->crypt_method_header);
break;
}
if (s->crypt_method_header != QCOW_CRYPT_NONE && !r->crypto_opts) {
ret = -EINVAL;
goto fail;
}
ret = 0;
fail:
qobject_unref(encryptopts);
qemu_opts_del(opts);
opts = NULL;
return ret;
}
static void qcow2_update_options_commit(BlockDriverState *bs,
Qcow2ReopenState *r)
{
BDRVQcow2State *s = bs->opaque;
int i;
if (s->l2_table_cache) {
qcow2_cache_destroy(s->l2_table_cache);
}
if (s->refcount_block_cache) {
qcow2_cache_destroy(s->refcount_block_cache);
}
s->l2_table_cache = r->l2_table_cache;
s->refcount_block_cache = r->refcount_block_cache;
s->l2_slice_size = r->l2_slice_size;
s->overlap_check = r->overlap_check;
s->use_lazy_refcounts = r->use_lazy_refcounts;
for (i = 0; i < QCOW2_DISCARD_MAX; i++) {
s->discard_passthrough[i] = r->discard_passthrough[i];
}
if (s->cache_clean_interval != r->cache_clean_interval) {
cache_clean_timer_del(bs);
s->cache_clean_interval = r->cache_clean_interval;
cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
}
qapi_free_QCryptoBlockOpenOptions(s->crypto_opts);
s->crypto_opts = r->crypto_opts;
}
static void qcow2_update_options_abort(BlockDriverState *bs,
Qcow2ReopenState *r)
{
if (r->l2_table_cache) {
qcow2_cache_destroy(r->l2_table_cache);
}
if (r->refcount_block_cache) {
qcow2_cache_destroy(r->refcount_block_cache);
}
qapi_free_QCryptoBlockOpenOptions(r->crypto_opts);
}
static int qcow2_update_options(BlockDriverState *bs, QDict *options,
int flags, Error **errp)
{
Qcow2ReopenState r = {};
int ret;
ret = qcow2_update_options_prepare(bs, &r, options, flags, errp);
if (ret >= 0) {
qcow2_update_options_commit(bs, &r);
} else {
qcow2_update_options_abort(bs, &r);
}
return ret;
}
/* Called with s->lock held. */
static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
int flags, Error **errp)
{
BDRVQcow2State *s = bs->opaque;
unsigned int len, i;
int ret = 0;
QCowHeader header;
Error *local_err = NULL;
uint64_t ext_end;
uint64_t l1_vm_state_index;
bool update_header = false;
ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read qcow2 header");
goto fail;
}
header.magic = be32_to_cpu(header.magic);
header.version = be32_to_cpu(header.version);
header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
header.backing_file_size = be32_to_cpu(header.backing_file_size);
header.size = be64_to_cpu(header.size);
header.cluster_bits = be32_to_cpu(header.cluster_bits);
header.crypt_method = be32_to_cpu(header.crypt_method);
header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
header.l1_size = be32_to_cpu(header.l1_size);
header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset);
header.refcount_table_clusters =
be32_to_cpu(header.refcount_table_clusters);
header.snapshots_offset = be64_to_cpu(header.snapshots_offset);
header.nb_snapshots = be32_to_cpu(header.nb_snapshots);
if (header.magic != QCOW_MAGIC) {
error_setg(errp, "Image is not in qcow2 format");
ret = -EINVAL;
goto fail;
}
if (header.version < 2 || header.version > 3) {
error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version);
ret = -ENOTSUP;
goto fail;
}
s->qcow_version = header.version;
/* Initialise cluster size */
if (header.cluster_bits < MIN_CLUSTER_BITS ||
header.cluster_bits > MAX_CLUSTER_BITS) {
error_setg(errp, "Unsupported cluster size: 2^%" PRIu32,
header.cluster_bits);
ret = -EINVAL;
goto fail;
}
s->cluster_bits = header.cluster_bits;
s->cluster_size = 1 << s->cluster_bits;
/* Initialise version 3 header fields */
if (header.version == 2) {
header.incompatible_features = 0;
header.compatible_features = 0;
header.autoclear_features = 0;
header.refcount_order = 4;
header.header_length = 72;
} else {
header.incompatible_features =
be64_to_cpu(header.incompatible_features);
header.compatible_features = be64_to_cpu(header.compatible_features);
header.autoclear_features = be64_to_cpu(header.autoclear_features);
header.refcount_order = be32_to_cpu(header.refcount_order);
header.header_length = be32_to_cpu(header.header_length);
if (header.header_length < 104) {
error_setg(errp, "qcow2 header too short");
ret = -EINVAL;
goto fail;
}
}
if (header.header_length > s->cluster_size) {
error_setg(errp, "qcow2 header exceeds cluster size");
ret = -EINVAL;
goto fail;
}
if (header.header_length > sizeof(header)) {
s->unknown_header_fields_size = header.header_length - sizeof(header);
s->unknown_header_fields = g_malloc(s->unknown_header_fields_size);
ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields,
s->unknown_header_fields_size);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read unknown qcow2 header "
"fields");
goto fail;
}
}
if (header.backing_file_offset > s->cluster_size) {
error_setg(errp, "Invalid backing file offset");
ret = -EINVAL;
goto fail;
}
if (header.backing_file_offset) {
ext_end = header.backing_file_offset;
} else {
ext_end = 1 << header.cluster_bits;
}
/* Handle feature bits */
s->incompatible_features = header.incompatible_features;
s->compatible_features = header.compatible_features;
s->autoclear_features = header.autoclear_features;
if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
void *feature_table = NULL;
qcow2_read_extensions(bs, header.header_length, ext_end,
&feature_table, flags, NULL, NULL);
report_unsupported_feature(errp, feature_table,
s->incompatible_features &
~QCOW2_INCOMPAT_MASK);
ret = -ENOTSUP;
g_free(feature_table);
goto fail;
}
if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
/* Corrupt images may not be written to unless they are being repaired
*/
if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
error_setg(errp, "qcow2: Image is corrupt; cannot be opened "
"read/write");
ret = -EACCES;
goto fail;
}
}
/* Check support for various header values */
if (header.refcount_order > 6) {
error_setg(errp, "Reference count entry width too large; may not "
"exceed 64 bits");
ret = -EINVAL;
goto fail;
}
s->refcount_order = header.refcount_order;
s->refcount_bits = 1 << s->refcount_order;
s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1);
s->refcount_max += s->refcount_max - 1;
s->crypt_method_header = header.crypt_method;
if (s->crypt_method_header) {
if (bdrv_uses_whitelist() &&
s->crypt_method_header == QCOW_CRYPT_AES) {
error_setg(errp,
"Use of AES-CBC encrypted qcow2 images is no longer "
"supported in system emulators");
error_append_hint(errp,
"You can use 'qemu-img convert' to convert your "
"image to an alternative supported format, such "
"as unencrypted qcow2, or raw with the LUKS "
"format instead.\n");
ret = -ENOSYS;
goto fail;
}
if (s->crypt_method_header == QCOW_CRYPT_AES) {
s->crypt_physical_offset = false;
} else {
/* Assuming LUKS and any future crypt methods we
* add will all use physical offsets, due to the
* fact that the alternative is insecure... */
s->crypt_physical_offset = true;
}
bs->encrypted = true;
}
s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
s->l2_size = 1 << s->l2_bits;
/* 2^(s->refcount_order - 3) is the refcount width in bytes */
s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
s->refcount_block_size = 1 << s->refcount_block_bits;
bs->total_sectors = header.size / BDRV_SECTOR_SIZE;
s->csize_shift = (62 - (s->cluster_bits - 8));
s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
s->refcount_table_offset = header.refcount_table_offset;
s->refcount_table_size =
header.refcount_table_clusters << (s->cluster_bits - 3);
if (header.refcount_table_clusters == 0 && !(flags & BDRV_O_CHECK)) {
error_setg(errp, "Image does not contain a reference count table");
ret = -EINVAL;
goto fail;
}
ret = qcow2_validate_table(bs, s->refcount_table_offset,
header.refcount_table_clusters,
s->cluster_size, QCOW_MAX_REFTABLE_SIZE,
"Reference count table", errp);
if (ret < 0) {
goto fail;
}
/* The total size in bytes of the snapshot table is checked in
* qcow2_read_snapshots() because the size of each snapshot is
* variable and we don't know it yet.
* Here we only check the offset and number of snapshots. */
ret = qcow2_validate_table(bs, header.snapshots_offset,
header.nb_snapshots,
sizeof(QCowSnapshotHeader),
sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS,
"Snapshot table", errp);
if (ret < 0) {
goto fail;
}
/* read the level 1 table */
ret = qcow2_validate_table(bs, header.l1_table_offset,
header.l1_size, sizeof(uint64_t),
QCOW_MAX_L1_SIZE, "Active L1 table", errp);
if (ret < 0) {
goto fail;
}
s->l1_size = header.l1_size;
s->l1_table_offset = header.l1_table_offset;
l1_vm_state_index = size_to_l1(s, header.size);
if (l1_vm_state_index > INT_MAX) {
error_setg(errp, "Image is too big");
ret = -EFBIG;
goto fail;
}
s->l1_vm_state_index = l1_vm_state_index;
/* the L1 table must contain at least enough entries to put
header.size bytes */
if (s->l1_size < s->l1_vm_state_index) {
error_setg(errp, "L1 table is too small");
ret = -EINVAL;
goto fail;
}
if (s->l1_size > 0) {
s->l1_table = qemu_try_blockalign(bs->file->bs,
ROUND_UP(s->l1_size * sizeof(uint64_t), 512));
if (s->l1_table == NULL) {
error_setg(errp, "Could not allocate L1 table");
ret = -ENOMEM;
goto fail;
}
ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
s->l1_size * sizeof(uint64_t));
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read L1 table");
goto fail;
}
for(i = 0;i < s->l1_size; i++) {
s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
}
}
/* Parse driver-specific options */
ret = qcow2_update_options(bs, options, flags, errp);
if (ret < 0) {
goto fail;
}
s->flags = flags;
ret = qcow2_refcount_init(bs);
if (ret != 0) {
error_setg_errno(errp, -ret, "Could not initialize refcount handling");
goto fail;
}
QLIST_INIT(&s->cluster_allocs);
QTAILQ_INIT(&s->discards);
/* read qcow2 extensions */
if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
flags, &update_header, &local_err)) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
/* Open external data file */
s->data_file = bdrv_open_child(NULL, options, "data-file", bs, &child_file,
true, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) {
if (!s->data_file && s->image_data_file) {
s->data_file = bdrv_open_child(s->image_data_file, options,
"data-file", bs, &child_file,
false, errp);
if (!s->data_file) {
ret = -EINVAL;
goto fail;
}
}
if (!s->data_file) {
error_setg(errp, "'data-file' is required for this image");
ret = -EINVAL;
goto fail;
}
} else {
if (s->data_file) {
error_setg(errp, "'data-file' can only be set for images with an "
"external data file");
ret = -EINVAL;
goto fail;
}
s->data_file = bs->file;
if (data_file_is_raw(bs)) {
error_setg(errp, "data-file-raw requires a data file");
ret = -EINVAL;
goto fail;
}
}
/* qcow2_read_extension may have set up the crypto context
* if the crypt method needs a header region, some methods
* don't need header extensions, so must check here
*/
if (s->crypt_method_header && !s->crypto) {
if (s->crypt_method_header == QCOW_CRYPT_AES) {
unsigned int cflags = 0;
if (flags & BDRV_O_NO_IO) {
cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
}
s->crypto = qcrypto_block_open(s->crypto_opts, "encrypt.",
NULL, NULL, cflags,
QCOW2_MAX_THREADS, errp);
if (!s->crypto) {
ret = -EINVAL;
goto fail;
}
} else if (!(flags & BDRV_O_NO_IO)) {
error_setg(errp, "Missing CRYPTO header for crypt method %d",
s->crypt_method_header);
ret = -EINVAL;
goto fail;
}
}
/* read the backing file name */
if (header.backing_file_offset != 0) {
len = header.backing_file_size;
if (len > MIN(1023, s->cluster_size - header.backing_file_offset) ||
len >= sizeof(bs->backing_file)) {
error_setg(errp, "Backing file name too long");
ret = -EINVAL;
goto fail;
}
ret = bdrv_pread(bs->file, header.backing_file_offset,
bs->auto_backing_file, len);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read backing file name");
goto fail;
}
bs->auto_backing_file[len] = '\0';
pstrcpy(bs->backing_file, sizeof(bs->backing_file),
bs->auto_backing_file);
s->image_backing_file = g_strdup(bs->auto_backing_file);
}
/* Internal snapshots */
s->snapshots_offset = header.snapshots_offset;
s->nb_snapshots = header.nb_snapshots;
ret = qcow2_read_snapshots(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not read snapshots");
goto fail;
}
/* Clear unknown autoclear feature bits */
update_header |= s->autoclear_features & ~QCOW2_AUTOCLEAR_MASK;
update_header =
update_header && !bs->read_only && !(flags & BDRV_O_INACTIVE);
if (update_header) {
s->autoclear_features &= QCOW2_AUTOCLEAR_MASK;
}
/* == Handle persistent dirty bitmaps ==
*
* We want load dirty bitmaps in three cases:
*
* 1. Normal open of the disk in active mode, not related to invalidation
* after migration.
*
* 2. Invalidation of the target vm after pre-copy phase of migration, if
* bitmaps are _not_ migrating through migration channel, i.e.
* 'dirty-bitmaps' capability is disabled.
*
* 3. Invalidation of source vm after failed or canceled migration.
* This is a very interesting case. There are two possible types of
* bitmaps:
*
* A. Stored on inactivation and removed. They should be loaded from the
* image.
*
* B. Not stored: not-persistent bitmaps and bitmaps, migrated through
* the migration channel (with dirty-bitmaps capability).
*
* On the other hand, there are two possible sub-cases:
*
* 3.1 disk was changed by somebody else while were inactive. In this
* case all in-RAM dirty bitmaps (both persistent and not) are
* definitely invalid. And we don't have any method to determine
* this.
*
* Simple and safe thing is to just drop all the bitmaps of type B on
* inactivation. But in this case we lose bitmaps in valid 4.2 case.
*
* On the other hand, resuming source vm, if disk was already changed
* is a bad thing anyway: not only bitmaps, the whole vm state is
* out of sync with disk.
*
* This means, that user or management tool, who for some reason
* decided to resume source vm, after disk was already changed by
* target vm, should at least drop all dirty bitmaps by hand.
*
* So, we can ignore this case for now, but TODO: "generation"
* extension for qcow2, to determine, that image was changed after
* last inactivation. And if it is changed, we will drop (or at least
* mark as 'invalid' all the bitmaps of type B, both persistent
* and not).
*
* 3.2 disk was _not_ changed while were inactive. Bitmaps may be saved
* to disk ('dirty-bitmaps' capability disabled), or not saved
* ('dirty-bitmaps' capability enabled), but we don't need to care
* of: let's load bitmaps as always: stored bitmaps will be loaded,
* and not stored has flag IN_USE=1 in the image and will be skipped
* on loading.
*
* One remaining possible case when we don't want load bitmaps:
*
* 4. Open disk in inactive mode in target vm (bitmaps are migrating or
* will be loaded on invalidation, no needs try loading them before)
*/
if (!(bdrv_get_flags(bs) & BDRV_O_INACTIVE)) {
/* It's case 1, 2 or 3.2. Or 3.1 which is BUG in management layer. */
bool header_updated = qcow2_load_dirty_bitmaps(bs, &local_err);
update_header = update_header && !header_updated;
}
if (local_err != NULL) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fail;
}
if (update_header) {
ret = qcow2_update_header(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not update qcow2 header");
goto fail;
}
}
bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0;
/* Repair image if dirty */
if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
(s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
BdrvCheckResult result = {0};
ret = qcow2_co_check_locked(bs, &result,
BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
if (ret < 0 || result.check_errors) {
if (ret >= 0) {
ret = -EIO;
}
error_setg_errno(errp, -ret, "Could not repair dirty image");
goto fail;
}
}
#ifdef DEBUG_ALLOC
{
BdrvCheckResult result = {0};
qcow2_check_refcounts(bs, &result, 0);
}
#endif
qemu_co_queue_init(&s->thread_task_queue);
return ret;
fail:
g_free(s->image_data_file);
if (has_data_file(bs)) {
bdrv_unref_child(bs, s->data_file);
}
g_free(s->unknown_header_fields);
cleanup_unknown_header_ext(bs);
qcow2_free_snapshots(bs);
qcow2_refcount_close(bs);
qemu_vfree(s->l1_table);
/* else pre-write overlap checks in cache_destroy may crash */
s->l1_table = NULL;
cache_clean_timer_del(bs);
if (s->l2_table_cache) {
qcow2_cache_destroy(s->l2_table_cache);
}
if (s->refcount_block_cache) {
qcow2_cache_destroy(s->refcount_block_cache);
}
qcrypto_block_free(s->crypto);
qapi_free_QCryptoBlockOpenOptions(s->crypto_opts);
return ret;
}
typedef struct QCow2OpenCo {
BlockDriverState *bs;
QDict *options;
int flags;
Error **errp;
int ret;
} QCow2OpenCo;
static void coroutine_fn qcow2_open_entry(void *opaque)
{
QCow2OpenCo *qoc = opaque;
BDRVQcow2State *s = qoc->bs->opaque;
qemu_co_mutex_lock(&s->lock);
qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, qoc->errp);
qemu_co_mutex_unlock(&s->lock);
}
static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
QCow2OpenCo qoc = {
.bs = bs,
.options = options,
.flags = flags,
.errp = errp,
.ret = -EINPROGRESS
};
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
false, errp);
if (!bs->file) {
return -EINVAL;
}
/* Initialise locks */
qemu_co_mutex_init(&s->lock);
if (qemu_in_coroutine()) {
/* From bdrv_co_create. */
qcow2_open_entry(&qoc);
} else {
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc));
BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS);
}
return qoc.ret;
}
static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVQcow2State *s = bs->opaque;
if (bs->encrypted) {
/* Encryption works on a sector granularity */
bs->bl.request_alignment = qcrypto_block_get_sector_size(s->crypto);
}
bs->bl.pwrite_zeroes_alignment = s->cluster_size;
bs->bl.pdiscard_alignment = s->cluster_size;
}
static int qcow2_reopen_prepare(BDRVReopenState *state,
BlockReopenQueue *queue, Error **errp)
{
Qcow2ReopenState *r;
int ret;
r = g_new0(Qcow2ReopenState, 1);
state->opaque = r;
ret = qcow2_update_options_prepare(state->bs, r, state->options,
state->flags, errp);
if (ret < 0) {
goto fail;
}
/* We need to write out any unwritten data if we reopen read-only. */
if ((state->flags & BDRV_O_RDWR) == 0) {
ret = qcow2_reopen_bitmaps_ro(state->bs, errp);
if (ret < 0) {
goto fail;
}
ret = bdrv_flush(state->bs);
if (ret < 0) {
goto fail;
}
ret = qcow2_mark_clean(state->bs);
if (ret < 0) {
goto fail;
}
}
return 0;
fail:
qcow2_update_options_abort(state->bs, r);
g_free(r);
return ret;
}
static void qcow2_reopen_commit(BDRVReopenState *state)
{
qcow2_update_options_commit(state->bs, state->opaque);
g_free(state->opaque);
}
static void qcow2_reopen_abort(BDRVReopenState *state)
{
qcow2_update_options_abort(state->bs, state->opaque);
g_free(state->opaque);
}
static void qcow2_join_options(QDict *options, QDict *old_options)
{
bool has_new_overlap_template =
qdict_haskey(options, QCOW2_OPT_OVERLAP) ||
qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE);
bool has_new_total_cache_size =
qdict_haskey(options, QCOW2_OPT_CACHE_SIZE);
bool has_all_cache_options;
/* New overlap template overrides all old overlap options */
if (has_new_overlap_template) {
qdict_del(old_options, QCOW2_OPT_OVERLAP);
qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE);
qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER);
qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1);
qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2);
qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE);
qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK);
qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE);
qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1);
qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2);
}
/* New total cache size overrides all old options */
if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) {
qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE);
qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
}
qdict_join(options, old_options, false);
/*
* If after merging all cache size options are set, an old total size is
* overwritten. Do keep all options, however, if all three are new. The
* resulting error message is what we want to happen.
*/
has_all_cache_options =
qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) ||
qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) ||
qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
if (has_all_cache_options && !has_new_total_cache_size) {
qdict_del(options, QCOW2_OPT_CACHE_SIZE);
}
}
static int coroutine_fn qcow2_co_block_status(BlockDriverState *bs,
bool want_zero,
int64_t offset, int64_t count,
int64_t *pnum, int64_t *map,
BlockDriverState **file)
{
BDRVQcow2State *s = bs->opaque;
uint64_t cluster_offset;
int index_in_cluster, ret;
unsigned int bytes;
int status = 0;
if (!s->metadata_preallocation_checked) {
ret = qcow2_detect_metadata_preallocation(bs);
s->metadata_preallocation = (ret == 1);
s->metadata_preallocation_checked = true;
}
bytes = MIN(INT_MAX, count);
qemu_co_mutex_lock(&s->lock);
ret = qcow2_get_cluster_offset(bs, offset, &bytes, &cluster_offset);
qemu_co_mutex_unlock(&s->lock);
if (ret < 0) {
return ret;
}
*pnum = bytes;
if ((ret == QCOW2_CLUSTER_NORMAL || ret == QCOW2_CLUSTER_ZERO_ALLOC) &&
!s->crypto) {
index_in_cluster = offset & (s->cluster_size - 1);
*map = cluster_offset | index_in_cluster;
*file = s->data_file->bs;
status |= BDRV_BLOCK_OFFSET_VALID;
}
if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) {
status |= BDRV_BLOCK_ZERO;
} else if (ret != QCOW2_CLUSTER_UNALLOCATED) {
status |= BDRV_BLOCK_DATA;
}
if (s->metadata_preallocation && (status & BDRV_BLOCK_DATA) &&
(status & BDRV_BLOCK_OFFSET_VALID))
{
status |= BDRV_BLOCK_RECURSE;
}
return status;
}
static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs,
QCowL2Meta **pl2meta,
bool link_l2)
{
int ret = 0;
QCowL2Meta *l2meta = *pl2meta;
while (l2meta != NULL) {
QCowL2Meta *next;
if (link_l2) {
ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
if (ret) {
goto out;
}
} else {
qcow2_alloc_cluster_abort(bs, l2meta);
}
/* Take the request off the list of running requests */
if (l2meta->nb_clusters != 0) {
QLIST_REMOVE(l2meta, next_in_flight);
}
qemu_co_queue_restart_all(&l2meta->dependent_requests);
next = l2meta->next;
g_free(l2meta);
l2meta = next;
}
out:
*pl2meta = l2meta;
return ret;
}
static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
BDRVQcow2State *s = bs->opaque;
int offset_in_cluster;
int ret;
unsigned int cur_bytes; /* number of bytes in current iteration */
uint64_t cluster_offset = 0;
uint64_t bytes_done = 0;
QEMUIOVector hd_qiov;
uint8_t *cluster_data = NULL;
qemu_iovec_init(&hd_qiov, qiov->niov);
while (bytes != 0) {
/* prepare next request */
cur_bytes = MIN(bytes, INT_MAX);
if (s->crypto) {
cur_bytes = MIN(cur_bytes,
QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
}
qemu_co_mutex_lock(&s->lock);
ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset);
qemu_co_mutex_unlock(&s->lock);
if (ret < 0) {
goto fail;
}
offset_in_cluster = offset_into_cluster(s, offset);
qemu_iovec_reset(&hd_qiov);
qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
switch (ret) {
case QCOW2_CLUSTER_UNALLOCATED:
if (bs->backing) {
BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
ret = bdrv_co_preadv(bs->backing, offset, cur_bytes,
&hd_qiov, 0);
if (ret < 0) {
goto fail;
}
} else {
/* Note: in this case, no need to wait */
qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
}
break;
case QCOW2_CLUSTER_ZERO_PLAIN:
case QCOW2_CLUSTER_ZERO_ALLOC:
qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
break;
case QCOW2_CLUSTER_COMPRESSED:
ret = qcow2_co_preadv_compressed(bs, cluster_offset,
offset, cur_bytes,
&hd_qiov);
if (ret < 0) {
goto fail;
}
break;
case QCOW2_CLUSTER_NORMAL:
if ((cluster_offset & 511) != 0) {
ret = -EIO;
goto fail;
}
if (bs->encrypted) {
assert(s->crypto);
/*
* For encrypted images, read everything into a temporary
* contiguous buffer on which the AES functions can work.
*/
if (!cluster_data) {
cluster_data =
qemu_try_blockalign(s->data_file->bs,
QCOW_MAX_CRYPT_CLUSTERS
* s->cluster_size);
if (cluster_data == NULL) {
ret = -ENOMEM;
goto fail;
}
}
assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
qemu_iovec_reset(&hd_qiov);
qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
}
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
ret = bdrv_co_preadv(s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, &hd_qiov, 0);
if (ret < 0) {
goto fail;
}
if (bs->encrypted) {
assert(s->crypto);
assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
if (qcow2_co_decrypt(bs, cluster_offset, offset,
cluster_data, cur_bytes) < 0) {
ret = -EIO;
goto fail;
}
qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
}
break;
default:
g_assert_not_reached();
ret = -EIO;
goto fail;
}
bytes -= cur_bytes;
offset += cur_bytes;
bytes_done += cur_bytes;
}
ret = 0;
fail:
qemu_iovec_destroy(&hd_qiov);
qemu_vfree(cluster_data);
return ret;
}
/* Check if it's possible to merge a write request with the writing of
* the data from the COW regions */
static bool merge_cow(uint64_t offset, unsigned bytes,
QEMUIOVector *hd_qiov, QCowL2Meta *l2meta)
{
QCowL2Meta *m;
for (m = l2meta; m != NULL; m = m->next) {
/* If both COW regions are empty then there's nothing to merge */
if (m->cow_start.nb_bytes == 0 && m->cow_end.nb_bytes == 0) {
continue;
}
/* If COW regions are handled already, skip this too */
if (m->skip_cow) {
continue;
}
/* The data (middle) region must be immediately after the
* start region */
if (l2meta_cow_start(m) + m->cow_start.nb_bytes != offset) {
continue;
}
/* The end region must be immediately after the data (middle)
* region */
if (m->offset + m->cow_end.offset != offset + bytes) {
continue;
}
/* Make sure that adding both COW regions to the QEMUIOVector
* does not exceed IOV_MAX */
if (hd_qiov->niov > IOV_MAX - 2) {
continue;
}
m->data_qiov = hd_qiov;
return true;
}
return false;
}
static bool is_unallocated(BlockDriverState *bs, int64_t offset, int64_t bytes)
{
int64_t nr;
return !bytes ||
(!bdrv_is_allocated_above(bs, NULL, false, offset, bytes, &nr) &&
nr == bytes);
}
static bool is_zero_cow(BlockDriverState *bs, QCowL2Meta *m)
{
/*
* This check is designed for optimization shortcut so it must be
* efficient.
* Instead of is_zero(), use is_unallocated() as it is faster (but not
* as accurate and can result in false negatives).
*/
return is_unallocated(bs, m->offset + m->cow_start.offset,
m->cow_start.nb_bytes) &&
is_unallocated(bs, m->offset + m->cow_end.offset,
m->cow_end.nb_bytes);
}
static int handle_alloc_space(BlockDriverState *bs, QCowL2Meta *l2meta)
{
BDRVQcow2State *s = bs->opaque;
QCowL2Meta *m;
if (!(s->data_file->bs->supported_zero_flags & BDRV_REQ_NO_FALLBACK)) {
return 0;
}
if (bs->encrypted) {
return 0;
}
for (m = l2meta; m != NULL; m = m->next) {
int ret;
if (!m->cow_start.nb_bytes && !m->cow_end.nb_bytes) {
continue;
}
if (!is_zero_cow(bs, m)) {
continue;
}
/*
* instead of writing zero COW buffers,
* efficiently zero out the whole clusters
*/
ret = qcow2_pre_write_overlap_check(bs, 0, m->alloc_offset,
m->nb_clusters * s->cluster_size,
true);
if (ret < 0) {
return ret;
}
BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC_SPACE);
ret = bdrv_co_pwrite_zeroes(s->data_file, m->alloc_offset,
m->nb_clusters * s->cluster_size,
BDRV_REQ_NO_FALLBACK);
if (ret < 0) {
if (ret != -ENOTSUP && ret != -EAGAIN) {
return ret;
}
continue;
}
trace_qcow2_skip_cow(qemu_coroutine_self(), m->offset, m->nb_clusters);
m->skip_cow = true;
}
return 0;
}
static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
BDRVQcow2State *s = bs->opaque;
int offset_in_cluster;
int ret;
unsigned int cur_bytes; /* number of sectors in current iteration */
uint64_t cluster_offset;
QEMUIOVector hd_qiov;
uint64_t bytes_done = 0;
uint8_t *cluster_data = NULL;
QCowL2Meta *l2meta = NULL;
trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes);
qemu_iovec_init(&hd_qiov, qiov->niov);
qemu_co_mutex_lock(&s->lock);
while (bytes != 0) {
l2meta = NULL;
trace_qcow2_writev_start_part(qemu_coroutine_self());
offset_in_cluster = offset_into_cluster(s, offset);
cur_bytes = MIN(bytes, INT_MAX);
if (bs->encrypted) {
cur_bytes = MIN(cur_bytes,
QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
- offset_in_cluster);
}
ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
&cluster_offset, &l2meta);
if (ret < 0) {
goto out_locked;
}
assert((cluster_offset & 511) == 0);
ret = qcow2_pre_write_overlap_check(bs, 0,
cluster_offset + offset_in_cluster,
cur_bytes, true);
if (ret < 0) {
goto out_locked;
}
qemu_co_mutex_unlock(&s->lock);
qemu_iovec_reset(&hd_qiov);
qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
if (bs->encrypted) {
assert(s->crypto);
if (!cluster_data) {
cluster_data = qemu_try_blockalign(bs->file->bs,
QCOW_MAX_CRYPT_CLUSTERS
* s->cluster_size);
if (cluster_data == NULL) {
ret = -ENOMEM;
goto out_unlocked;
}
}
assert(hd_qiov.size <=
QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
if (qcow2_co_encrypt(bs, cluster_offset, offset,
cluster_data, cur_bytes) < 0) {
ret = -EIO;
goto out_unlocked;
}
qemu_iovec_reset(&hd_qiov);
qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
}
/* Try to efficiently initialize the physical space with zeroes */
ret = handle_alloc_space(bs, l2meta);
if (ret < 0) {
goto out_unlocked;
}
/* If we need to do COW, check if it's possible to merge the
* writing of the guest data together with that of the COW regions.
* If it's not possible (or not necessary) then write the
* guest data now. */
if (!merge_cow(offset, cur_bytes, &hd_qiov, l2meta)) {
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
trace_qcow2_writev_data(qemu_coroutine_self(),
cluster_offset + offset_in_cluster);
ret = bdrv_co_pwritev(s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, &hd_qiov, 0);
if (ret < 0) {
goto out_unlocked;
}
}
qemu_co_mutex_lock(&s->lock);
ret = qcow2_handle_l2meta(bs, &l2meta, true);
if (ret) {
goto out_locked;
}
bytes -= cur_bytes;
offset += cur_bytes;
bytes_done += cur_bytes;
trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes);
}
ret = 0;
goto out_locked;
out_unlocked:
qemu_co_mutex_lock(&s->lock);
out_locked:
qcow2_handle_l2meta(bs, &l2meta, false);
qemu_co_mutex_unlock(&s->lock);
qemu_iovec_destroy(&hd_qiov);
qemu_vfree(cluster_data);
trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
return ret;
}
static int qcow2_inactivate(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
int ret, result = 0;
Error *local_err = NULL;
qcow2_store_persistent_dirty_bitmaps(bs, &local_err);
if (local_err != NULL) {
result = -EINVAL;
error_reportf_err(local_err, "Lost persistent bitmaps during "
"inactivation of node '%s': ",
bdrv_get_device_or_node_name(bs));
}
ret = qcow2_cache_flush(bs, s->l2_table_cache);
if (ret) {
result = ret;
error_report("Failed to flush the L2 table cache: %s",
strerror(-ret));
}
ret = qcow2_cache_flush(bs, s->refcount_block_cache);
if (ret) {
result = ret;
error_report("Failed to flush the refcount block cache: %s",
strerror(-ret));
}
if (result == 0) {
qcow2_mark_clean(bs);
}
return result;
}
static void qcow2_close(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
qemu_vfree(s->l1_table);
/* else pre-write overlap checks in cache_destroy may crash */
s->l1_table = NULL;
if (!(s->flags & BDRV_O_INACTIVE)) {
qcow2_inactivate(bs);
}
cache_clean_timer_del(bs);
qcow2_cache_destroy(s->l2_table_cache);
qcow2_cache_destroy(s->refcount_block_cache);
qcrypto_block_free(s->crypto);
s->crypto = NULL;
g_free(s->unknown_header_fields);
cleanup_unknown_header_ext(bs);
g_free(s->image_data_file);
g_free(s->image_backing_file);
g_free(s->image_backing_format);
if (has_data_file(bs)) {
bdrv_unref_child(bs, s->data_file);
}
qcow2_refcount_close(bs);
qcow2_free_snapshots(bs);
}
static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
int flags = s->flags;
QCryptoBlock *crypto = NULL;
QDict *options;
Error *local_err = NULL;
int ret;
/*
* Backing files are read-only which makes all of their metadata immutable,
* that means we don't have to worry about reopening them here.
*/
crypto = s->crypto;
s->crypto = NULL;
qcow2_close(bs);
memset(s, 0, sizeof(BDRVQcow2State));
options = qdict_clone_shallow(bs->options);
flags &= ~BDRV_O_INACTIVE;
qemu_co_mutex_lock(&s->lock);
ret = qcow2_do_open(bs, options, flags, &local_err);
qemu_co_mutex_unlock(&s->lock);
qobject_unref(options);
if (local_err) {
error_propagate_prepend(errp, local_err,
"Could not reopen qcow2 layer: ");
bs->drv = NULL;
return;
} else if (ret < 0) {
error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
bs->drv = NULL;
return;
}
s->crypto = crypto;
}
static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
size_t len, size_t buflen)
{
QCowExtension *ext_backing_fmt = (QCowExtension*) buf;
size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7);
if (buflen < ext_len) {
return -ENOSPC;
}
*ext_backing_fmt = (QCowExtension) {
.magic = cpu_to_be32(magic),
.len = cpu_to_be32(len),
};
if (len) {
memcpy(buf + sizeof(QCowExtension), s, len);
}
return ext_len;
}
/*
* Updates the qcow2 header, including the variable length parts of it, i.e.
* the backing file name and all extensions. qcow2 was not designed to allow
* such changes, so if we run out of space (we can only use the first cluster)
* this function may fail.
*
* Returns 0 on success, -errno in error cases.
*/
int qcow2_update_header(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
QCowHeader *header;
char *buf;
size_t buflen = s->cluster_size;
int ret;
uint64_t total_size;
uint32_t refcount_table_clusters;
size_t header_length;
Qcow2UnknownHeaderExtension *uext;
buf = qemu_blockalign(bs, buflen);
/* Header structure */
header = (QCowHeader*) buf;
if (buflen < sizeof(*header)) {
ret = -ENOSPC;
goto fail;
}
header_length = sizeof(*header) + s->unknown_header_fields_size;
total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
*header = (QCowHeader) {
/* Version 2 fields */
.magic = cpu_to_be32(QCOW_MAGIC),
.version = cpu_to_be32(s->qcow_version),
.backing_file_offset = 0,
.backing_file_size = 0,
.cluster_bits = cpu_to_be32(s->cluster_bits),
.size = cpu_to_be64(total_size),
.crypt_method = cpu_to_be32(s->crypt_method_header),
.l1_size = cpu_to_be32(s->l1_size),
.l1_table_offset = cpu_to_be64(s->l1_table_offset),
.refcount_table_offset = cpu_to_be64(s->refcount_table_offset),
.refcount_table_clusters = cpu_to_be32(refcount_table_clusters),
.nb_snapshots = cpu_to_be32(s->nb_snapshots),
.snapshots_offset = cpu_to_be64(s->snapshots_offset),
/* Version 3 fields */
.incompatible_features = cpu_to_be64(s->incompatible_features),
.compatible_features = cpu_to_be64(s->compatible_features),
.autoclear_features = cpu_to_be64(s->autoclear_features),
.refcount_order = cpu_to_be32(s->refcount_order),
.header_length = cpu_to_be32(header_length),
};
/* For older versions, write a shorter header */
switch (s->qcow_version) {
case 2:
ret = offsetof(QCowHeader, incompatible_features);
break;
case 3:
ret = sizeof(*header);
break;
default:
ret = -EINVAL;
goto fail;
}
buf += ret;
buflen -= ret;
memset(buf, 0, buflen);
/* Preserve any unknown field in the header */
if (s->unknown_header_fields_size) {
if (buflen < s->unknown_header_fields_size) {
ret = -ENOSPC;
goto fail;
}
memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size);
buf += s->unknown_header_fields_size;
buflen -= s->unknown_header_fields_size;
}
/* Backing file format header extension */
if (s->image_backing_format) {
ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT,
s->image_backing_format,
strlen(s->image_backing_format),
buflen);
if (ret < 0) {
goto fail;
}
buf += ret;
buflen -= ret;
}
/* External data file header extension */
if (has_data_file(bs) && s->image_data_file) {
ret = header_ext_add(buf, QCOW2_EXT_MAGIC_DATA_FILE,
s->image_data_file, strlen(s->image_data_file),
buflen);
if (ret < 0) {
goto fail;
}
buf += ret;
buflen -= ret;
}
/* Full disk encryption header pointer extension */
if (s->crypto_header.offset != 0) {
s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset);
s->crypto_header.length = cpu_to_be64(s->crypto_header.length);
ret = header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER,
&s->crypto_header, sizeof(s->crypto_header),
buflen);
s->crypto_header.offset = be64_to_cpu(s->crypto_header.offset);
s->crypto_header.length = be64_to_cpu(s->crypto_header.length);
if (ret < 0) {
goto fail;
}
buf += ret;
buflen -= ret;
}
/* Feature table */
if (s->qcow_version >= 3) {
Qcow2Feature features[] = {
{
.type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
.bit = QCOW2_INCOMPAT_DIRTY_BITNR,
.name = "dirty bit",
},
{
.type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
.bit = QCOW2_INCOMPAT_CORRUPT_BITNR,
.name = "corrupt bit",
},
{
.type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
.bit = QCOW2_INCOMPAT_DATA_FILE_BITNR,
.name = "external data file",
},
{
.type = QCOW2_FEAT_TYPE_COMPATIBLE,
.bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
.name = "lazy refcounts",
},
};
ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
features, sizeof(features), buflen);
if (ret < 0) {
goto fail;
}
buf += ret;
buflen -= ret;
}
/* Bitmap extension */
if (s->nb_bitmaps > 0) {
Qcow2BitmapHeaderExt bitmaps_header = {
.nb_bitmaps = cpu_to_be32(s->nb_bitmaps),
.bitmap_directory_size =
cpu_to_be64(s->bitmap_directory_size),
.bitmap_directory_offset =
cpu_to_be64(s->bitmap_directory_offset)
};
ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BITMAPS,
&bitmaps_header, sizeof(bitmaps_header),
buflen);
if (ret < 0) {
goto fail;
}
buf += ret;
buflen -= ret;
}
/* Keep unknown header extensions */
QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
if (ret < 0) {
goto fail;
}
buf += ret;
buflen -= ret;
}
/* End of header extensions */
ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen);
if (ret < 0) {
goto fail;
}
buf += ret;
buflen -= ret;
/* Backing file name */
if (s->image_backing_file) {
size_t backing_file_len = strlen(s->image_backing_file);
if (buflen < backing_file_len) {
ret = -ENOSPC;
goto fail;
}
/* Using strncpy is ok here, since buf is not NUL-terminated. */
strncpy(buf, s->image_backing_file, buflen);
header->backing_file_offset = cpu_to_be64(buf - ((char*) header));
header->backing_file_size = cpu_to_be32(backing_file_len);
}
/* Write the new header */
ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size);
if (ret < 0) {
goto fail;
}
ret = 0;
fail:
qemu_vfree(header);
return ret;
}
static int qcow2_change_backing_file(BlockDriverState *bs,
const char *backing_file, const char *backing_fmt)
{
BDRVQcow2State *s = bs->opaque;
/* Adding a backing file means that the external data file alone won't be
* enough to make sense of the content */
if (backing_file && data_file_is_raw(bs)) {
return -EINVAL;
}
if (backing_file && strlen(backing_file) > 1023) {
return -EINVAL;
}
pstrcpy(bs->auto_backing_file, sizeof(bs->auto_backing_file),
backing_file ?: "");
pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
g_free(s->image_backing_file);
g_free(s->image_backing_format);
s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
return qcow2_update_header(bs);
}
static int qcow2_crypt_method_from_format(const char *encryptfmt)
{
if (g_str_equal(encryptfmt, "luks")) {
return QCOW_CRYPT_LUKS;
} else if (g_str_equal(encryptfmt, "aes")) {
return QCOW_CRYPT_AES;
} else {
return -EINVAL;
}
}
static int qcow2_set_up_encryption(BlockDriverState *bs,
QCryptoBlockCreateOptions *cryptoopts,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
QCryptoBlock *crypto = NULL;
int fmt, ret;
switch (cryptoopts->format) {
case Q_CRYPTO_BLOCK_FORMAT_LUKS:
fmt = QCOW_CRYPT_LUKS;
break;
case Q_CRYPTO_BLOCK_FORMAT_QCOW:
fmt = QCOW_CRYPT_AES;
break;
default:
error_setg(errp, "Crypto format not supported in qcow2");
return -EINVAL;
}
s->crypt_method_header = fmt;
crypto = qcrypto_block_create(cryptoopts, "encrypt.",
qcow2_crypto_hdr_init_func,
qcow2_crypto_hdr_write_func,
bs, errp);
if (!crypto) {
return -EINVAL;
}
ret = qcow2_update_header(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not write encryption header");
goto out;
}
ret = 0;
out:
qcrypto_block_free(crypto);
return ret;
}
/**
* Preallocates metadata structures for data clusters between @offset (in the
* guest disk) and @new_length (which is thus generally the new guest disk
* size).
*
* Returns: 0 on success, -errno on failure.
*/
static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
uint64_t new_length, PreallocMode mode,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
uint64_t bytes;
uint64_t host_offset = 0;
int64_t file_length;
unsigned int cur_bytes;
int ret;
QCowL2Meta *meta;
assert(offset <= new_length);
bytes = new_length - offset;
while (bytes) {
cur_bytes = MIN(bytes, QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size));
ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
&host_offset, &meta);
if (ret < 0) {
error_setg_errno(errp, -ret, "Allocating clusters failed");
return ret;
}
while (meta) {
QCowL2Meta *next = meta->next;
ret = qcow2_alloc_cluster_link_l2(bs, meta);
if (ret < 0) {
error_setg_errno(errp, -ret, "Mapping clusters failed");
qcow2_free_any_clusters(bs, meta->alloc_offset,
meta->nb_clusters, QCOW2_DISCARD_NEVER);
return ret;
}
/* There are no dependent requests, but we need to remove our
* request from the list of in-flight requests */
QLIST_REMOVE(meta, next_in_flight);
g_free(meta);
meta = next;
}
/* TODO Preallocate data if requested */
bytes -= cur_bytes;
offset += cur_bytes;
}
/*
* It is expected that the image file is large enough to actually contain
* all of the allocated clusters (otherwise we get failing reads after
* EOF). Extend the image to the last allocated sector.
*/
file_length = bdrv_getlength(s->data_file->bs);
if (file_length < 0) {
error_setg_errno(errp, -file_length, "Could not get file size");
return file_length;
}
if (host_offset + cur_bytes > file_length) {
if (mode == PREALLOC_MODE_METADATA) {
mode = PREALLOC_MODE_OFF;
}
ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, mode,
errp);
if (ret < 0) {
return ret;
}
}
return 0;
}
/* qcow2_refcount_metadata_size:
* @clusters: number of clusters to refcount (including data and L1/L2 tables)
* @cluster_size: size of a cluster, in bytes
* @refcount_order: refcount bits power-of-2 exponent
* @generous_increase: allow for the refcount table to be 1.5x as large as it
* needs to be
*
* Returns: Number of bytes required for refcount blocks and table metadata.
*/
int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
int refcount_order, bool generous_increase,
uint64_t *refblock_count)
{
/*
* Every host cluster is reference-counted, including metadata (even
* refcount metadata is recursively included).
*
* An accurate formula for the size of refcount metadata size is difficult
* to derive. An easier method of calculation is finding the fixed point
* where no further refcount blocks or table clusters are required to
* reference count every cluster.
*/
int64_t blocks_per_table_cluster = cluster_size / sizeof(uint64_t);
int64_t refcounts_per_block = cluster_size * 8 / (1 << refcount_order);
int64_t table = 0; /* number of refcount table clusters */
int64_t blocks = 0; /* number of refcount block clusters */
int64_t last;
int64_t n = 0;
do {
last = n;
blocks = DIV_ROUND_UP(clusters + table + blocks, refcounts_per_block);
table = DIV_ROUND_UP(blocks, blocks_per_table_cluster);
n = clusters + blocks + table;
if (n == last && generous_increase) {
clusters += DIV_ROUND_UP(table, 2);
n = 0; /* force another loop */
generous_increase = false;
}
} while (n != last);
if (refblock_count) {
*refblock_count = blocks;
}
return (blocks + table) * cluster_size;
}
/**
* qcow2_calc_prealloc_size:
* @total_size: virtual disk size in bytes
* @cluster_size: cluster size in bytes
* @refcount_order: refcount bits power-of-2 exponent
*
* Returns: Total number of bytes required for the fully allocated image
* (including metadata).
*/
static int64_t qcow2_calc_prealloc_size(int64_t total_size,
size_t cluster_size,
int refcount_order)
{
int64_t meta_size = 0;
uint64_t nl1e, nl2e;
int64_t aligned_total_size = ROUND_UP(total_size, cluster_size);
/* header: 1 cluster */
meta_size += cluster_size;
/* total size of L2 tables */
nl2e = aligned_total_size / cluster_size;
nl2e = ROUND_UP(nl2e, cluster_size / sizeof(uint64_t));
meta_size += nl2e * sizeof(uint64_t);
/* total size of L1 tables */
nl1e = nl2e * sizeof(uint64_t) / cluster_size;
nl1e = ROUND_UP(nl1e, cluster_size / sizeof(uint64_t));
meta_size += nl1e * sizeof(uint64_t);
/* total size of refcount table and blocks */
meta_size += qcow2_refcount_metadata_size(
(meta_size + aligned_total_size) / cluster_size,
cluster_size, refcount_order, false, NULL);
return meta_size + aligned_total_size;
}
static bool validate_cluster_size(size_t cluster_size, Error **errp)
{
int cluster_bits = ctz32(cluster_size);
if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
(1 << cluster_bits) != cluster_size)
{
error_setg(errp, "Cluster size must be a power of two between %d and "
"%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
return false;
}
return true;
}
static size_t qcow2_opt_get_cluster_size_del(QemuOpts *opts, Error **errp)
{
size_t cluster_size;
cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
DEFAULT_CLUSTER_SIZE);
if (!validate_cluster_size(cluster_size, errp)) {
return 0;
}
return cluster_size;
}
static int qcow2_opt_get_version_del(QemuOpts *opts, Error **errp)
{
char *buf;
int ret;
buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL);
if (!buf) {
ret = 3; /* default */
} else if (!strcmp(buf, "0.10")) {
ret = 2;
} else if (!strcmp(buf, "1.1")) {
ret = 3;
} else {
error_setg(errp, "Invalid compatibility level: '%s'", buf);
ret = -EINVAL;
}
g_free(buf);
return ret;
}
static uint64_t qcow2_opt_get_refcount_bits_del(QemuOpts *opts, int version,
Error **errp)
{
uint64_t refcount_bits;
refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 16);
if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) {
error_setg(errp, "Refcount width must be a power of two and may not "
"exceed 64 bits");
return 0;
}
if (version < 3 && refcount_bits != 16) {
error_setg(errp, "Different refcount widths than 16 bits require "
"compatibility level 1.1 or above (use compat=1.1 or "
"greater)");
return 0;
}
return refcount_bits;
}
static int coroutine_fn
qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
{
BlockdevCreateOptionsQcow2 *qcow2_opts;
QDict *options;
/*
* Open the image file and write a minimal qcow2 header.
*
* We keep things simple and start with a zero-sized image. We also
* do without refcount blocks or a L1 table for now. We'll fix the
* inconsistency later.
*
* We do need a refcount table because growing the refcount table means
* allocating two new refcount blocks - the seconds of which would be at
* 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
* size for any qcow2 image.
*/
BlockBackend *blk = NULL;
BlockDriverState *bs = NULL;
BlockDriverState *data_bs = NULL;
QCowHeader *header;
size_t cluster_size;
int version;
int refcount_order;
uint64_t* refcount_table;
Error *local_err = NULL;
int ret;
assert(create_options->driver == BLOCKDEV_DRIVER_QCOW2);
qcow2_opts = &create_options->u.qcow2;
bs = bdrv_open_blockdev_ref(qcow2_opts->file, errp);
if (bs == NULL) {
return -EIO;
}
/* Validate options and set default values */
if (!QEMU_IS_ALIGNED(qcow2_opts->size, BDRV_SECTOR_SIZE)) {
error_setg(errp, "Image size must be a multiple of 512 bytes");
ret = -EINVAL;
goto out;
}
if (qcow2_opts->has_version) {
switch (qcow2_opts->version) {
case BLOCKDEV_QCOW2_VERSION_V2:
version = 2;
break;
case BLOCKDEV_QCOW2_VERSION_V3:
version = 3;
break;
default:
g_assert_not_reached();
}
} else {
version = 3;
}
if (qcow2_opts->has_cluster_size) {
cluster_size = qcow2_opts->cluster_size;
} else {
cluster_size = DEFAULT_CLUSTER_SIZE;
}
if (!validate_cluster_size(cluster_size, errp)) {
ret = -EINVAL;
goto out;
}
if (!qcow2_opts->has_preallocation) {
qcow2_opts->preallocation = PREALLOC_MODE_OFF;
}
if (qcow2_opts->has_backing_file &&
qcow2_opts->preallocation != PREALLOC_MODE_OFF)
{
error_setg(errp, "Backing file and preallocation cannot be used at "
"the same time");
ret = -EINVAL;
goto out;
}
if (qcow2_opts->has_backing_fmt && !qcow2_opts->has_backing_file) {
error_setg(errp, "Backing format cannot be used without backing file");
ret = -EINVAL;
goto out;
}
if (!qcow2_opts->has_lazy_refcounts) {
qcow2_opts->lazy_refcounts = false;
}
if (version < 3 && qcow2_opts->lazy_refcounts) {
error_setg(errp, "Lazy refcounts only supported with compatibility "
"level 1.1 and above (use version=v3 or greater)");
ret = -EINVAL;
goto out;
}
if (!qcow2_opts->has_refcount_bits) {
qcow2_opts->refcount_bits = 16;
}
if (qcow2_opts->refcount_bits > 64 ||
!is_power_of_2(qcow2_opts->refcount_bits))
{
error_setg(errp, "Refcount width must be a power of two and may not "
"exceed 64 bits");
ret = -EINVAL;
goto out;
}
if (version < 3 && qcow2_opts->refcount_bits != 16) {
error_setg(errp, "Different refcount widths than 16 bits require "
"compatibility level 1.1 or above (use version=v3 or "
"greater)");
ret = -EINVAL;
goto out;
}
refcount_order = ctz32(qcow2_opts->refcount_bits);
if (qcow2_opts->data_file_raw && !qcow2_opts->data_file) {
error_setg(errp, "data-file-raw requires data-file");
ret = -EINVAL;
goto out;
}
if (qcow2_opts->data_file_raw && qcow2_opts->has_backing_file) {
error_setg(errp, "Backing file and data-file-raw cannot be used at "
"the same time");
ret = -EINVAL;
goto out;
}
if (qcow2_opts->data_file) {
if (version < 3) {
error_setg(errp, "External data files are only supported with "
"compatibility level 1.1 and above (use version=v3 or "
"greater)");
ret = -EINVAL;
goto out;
}
data_bs = bdrv_open_blockdev_ref(qcow2_opts->data_file, errp);
if (data_bs == NULL) {
ret = -EIO;
goto out;
}
}
/* Create BlockBackend to write to the image */
blk = blk_new(bdrv_get_aio_context(bs),
BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
ret = blk_insert_bs(blk, bs, errp);
if (ret < 0) {
goto out;
}
blk_set_allow_write_beyond_eof(blk, true);
/* Clear the protocol layer and preallocate it if necessary */
ret = blk_truncate(blk, 0, PREALLOC_MODE_OFF, errp);
if (ret < 0) {
goto out;
}
/* Write the header */
QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
header = g_malloc0(cluster_size);
*header = (QCowHeader) {
.magic = cpu_to_be32(QCOW_MAGIC),
.version = cpu_to_be32(version),
.cluster_bits = cpu_to_be32(ctz32(cluster_size)),
.size = cpu_to_be64(0),
.l1_table_offset = cpu_to_be64(0),
.l1_size = cpu_to_be32(0),
.refcount_table_offset = cpu_to_be64(cluster_size),
.refcount_table_clusters = cpu_to_be32(1),
.refcount_order = cpu_to_be32(refcount_order),
.header_length = cpu_to_be32(sizeof(*header)),
};
/* We'll update this to correct value later */
header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
if (qcow2_opts->lazy_refcounts) {
header->compatible_features |=
cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);
}
if (data_bs) {
header->incompatible_features |=
cpu_to_be64(QCOW2_INCOMPAT_DATA_FILE);
}
if (qcow2_opts->data_file_raw) {
header->autoclear_features |=
cpu_to_be64(QCOW2_AUTOCLEAR_DATA_FILE_RAW);
}
ret = blk_pwrite(blk, 0, header, cluster_size, 0);
g_free(header);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not write qcow2 header");
goto out;
}
/* Write a refcount table with one refcount block */
refcount_table = g_malloc0(2 * cluster_size);
refcount_table[0] = cpu_to_be64(2 * cluster_size);
ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0);
g_free(refcount_table);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not write refcount table");
goto out;
}
blk_unref(blk);
blk = NULL;
/*
* And now open the image and make it consistent first (i.e. increase the
* refcount of the cluster that is occupied by the header and the refcount
* table)
*/
options = qdict_new();
qdict_put_str(options, "driver", "qcow2");
qdict_put_str(options, "file", bs->node_name);
if (data_bs) {
qdict_put_str(options, "data-file", data_bs->node_name);
}
blk = blk_new_open(NULL, NULL, options,
BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH,
&local_err);
if (blk == NULL) {
error_propagate(errp, local_err);
ret = -EIO;
goto out;
}
ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 "
"header and refcount table");
goto out;
} else if (ret != 0) {
error_report("Huh, first cluster in empty image is already in use?");
abort();
}
/* Set the external data file if necessary */
if (data_bs) {
BDRVQcow2State *s = blk_bs(blk)->opaque;
s->image_data_file = g_strdup(data_bs->filename);
}
/* Create a full header (including things like feature table) */
ret = qcow2_update_header(blk_bs(blk));
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not update qcow2 header");
goto out;
}
/* Okay, now that we have a valid image, let's give it the right size */
ret = blk_truncate(blk, qcow2_opts->size, qcow2_opts->preallocation, errp);
if (ret < 0) {
error_prepend(errp, "Could not resize image: ");
goto out;
}
/* Want a backing file? There you go.*/
if (qcow2_opts->has_backing_file) {
const char *backing_format = NULL;
if (qcow2_opts->has_backing_fmt) {
backing_format = BlockdevDriver_str(qcow2_opts->backing_fmt);
}
ret = bdrv_change_backing_file(blk_bs(blk), qcow2_opts->backing_file,
backing_format);
if (ret < 0) {
error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
"with format '%s'", qcow2_opts->backing_file,
backing_format);
goto out;
}
}
/* Want encryption? There you go. */
if (qcow2_opts->has_encrypt) {
ret = qcow2_set_up_encryption(blk_bs(blk), qcow2_opts->encrypt, errp);
if (ret < 0) {
goto out;
}
}
blk_unref(blk);
blk = NULL;
/* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning.
* Using BDRV_O_NO_IO, since encryption is now setup we don't want to
* have to setup decryption context. We're not doing any I/O on the top
* level BlockDriverState, only lower layers, where BDRV_O_NO_IO does
* not have effect.
*/
options = qdict_new();
qdict_put_str(options, "driver", "qcow2");
qdict_put_str(options, "file", bs->node_name);
if (data_bs) {
qdict_put_str(options, "data-file", data_bs->node_name);
}
blk = blk_new_open(NULL, NULL, options,
BDRV_O_RDWR | BDRV_O_NO_BACKING | BDRV_O_NO_IO,
&local_err);
if (blk == NULL) {
error_propagate(errp, local_err);
ret = -EIO;
goto out;
}
ret = 0;
out:
blk_unref(blk);
bdrv_unref(bs);
bdrv_unref(data_bs);
return ret;
}
static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opts,
Error **errp)
{
BlockdevCreateOptions *create_options = NULL;
QDict *qdict;
Visitor *v;
BlockDriverState *bs = NULL;
BlockDriverState *data_bs = NULL;
Error *local_err = NULL;
const char *val;
int ret;
/* Only the keyval visitor supports the dotted syntax needed for
* encryption, so go through a QDict before getting a QAPI type. Ignore
* options meant for the protocol layer so that the visitor doesn't
* complain. */
qdict = qemu_opts_to_qdict_filtered(opts, NULL, bdrv_qcow2.create_opts,
true);
/* Handle encryption options */
val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
if (val && !strcmp(val, "on")) {
qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
} else if (val && !strcmp(val, "off")) {
qdict_del(qdict, BLOCK_OPT_ENCRYPT);
}
val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
if (val && !strcmp(val, "aes")) {
qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
}
/* Convert compat=0.10/1.1 into compat=v2/v3, to be renamed into
* version=v2/v3 below. */
val = qdict_get_try_str(qdict, BLOCK_OPT_COMPAT_LEVEL);
if (val && !strcmp(val, "0.10")) {
qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v2");
} else if (val && !strcmp(val, "1.1")) {
qdict_put_str(qdict, BLOCK_OPT_COMPAT_LEVEL, "v3");
}
/* Change legacy command line options into QMP ones */
static const QDictRenames opt_renames[] = {
{ BLOCK_OPT_BACKING_FILE, "backing-file" },
{ BLOCK_OPT_BACKING_FMT, "backing-fmt" },
{ BLOCK_OPT_CLUSTER_SIZE, "cluster-size" },
{ BLOCK_OPT_LAZY_REFCOUNTS, "lazy-refcounts" },
{ BLOCK_OPT_REFCOUNT_BITS, "refcount-bits" },
{ BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
{ BLOCK_OPT_COMPAT_LEVEL, "version" },
{ BLOCK_OPT_DATA_FILE_RAW, "data-file-raw" },
{ NULL, NULL },
};
if (!qdict_rename_keys(qdict, opt_renames, errp)) {
ret = -EINVAL;
goto finish;
}
/* Create and open the file (protocol layer) */
ret = bdrv_create_file(filename, opts, errp);
if (ret < 0) {
goto finish;
}
bs = bdrv_open(filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
if (bs == NULL) {
ret = -EIO;
goto finish;
}
/* Create and open an external data file (protocol layer) */
val = qdict_get_try_str(qdict, BLOCK_OPT_DATA_FILE);
if (val) {
ret = bdrv_create_file(val, opts, errp);
if (ret < 0) {
goto finish;
}
data_bs = bdrv_open(val, NULL, NULL,
BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL,
errp);
if (data_bs == NULL) {
ret = -EIO;
goto finish;
}
qdict_del(qdict, BLOCK_OPT_DATA_FILE);
qdict_put_str(qdict, "data-file", data_bs->node_name);
}
/* Set 'driver' and 'node' options */
qdict_put_str(qdict, "driver", "qcow2");
qdict_put_str(qdict, "file", bs->node_name);
/* Now get the QAPI type BlockdevCreateOptions */
v = qobject_input_visitor_new_flat_confused(qdict, errp);
if (!v) {
ret = -EINVAL;
goto finish;
}
visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err);
visit_free(v);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto finish;
}
/* Silently round up size */
create_options->u.qcow2.size = ROUND_UP(create_options->u.qcow2.size,
BDRV_SECTOR_SIZE);
/* Create the qcow2 image (format layer) */
ret = qcow2_co_create(create_options, errp);
if (ret < 0) {
goto finish;
}
ret = 0;
finish:
qobject_unref(qdict);
bdrv_unref(bs);
bdrv_unref(data_bs);
qapi_free_BlockdevCreateOptions(create_options);
return ret;
}
static bool is_zero(BlockDriverState *bs, int64_t offset, int64_t bytes)
{
int64_t nr;
int res;
/* Clamp to image length, before checking status of underlying sectors */
if (offset + bytes > bs->total_sectors * BDRV_SECTOR_SIZE) {
bytes = bs->total_sectors * BDRV_SECTOR_SIZE - offset;
}
if (!bytes) {
return true;
}
res = bdrv_block_status_above(bs, NULL, offset, bytes, &nr, NULL, NULL);
return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == bytes;
}
static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int bytes, BdrvRequestFlags flags)
{
int ret;
BDRVQcow2State *s = bs->opaque;
uint32_t head = offset % s->cluster_size;
uint32_t tail = (offset + bytes) % s->cluster_size;
trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, bytes);
if (offset + bytes == bs->total_sectors * BDRV_SECTOR_SIZE) {
tail = 0;
}
if (head || tail) {
uint64_t off;
unsigned int nr;
assert(head + bytes <= s->cluster_size);
/* check whether remainder of cluster already reads as zero */
if (!(is_zero(bs, offset - head, head) &&
is_zero(bs, offset + bytes,
tail ? s->cluster_size - tail : 0))) {
return -ENOTSUP;
}
qemu_co_mutex_lock(&s->lock);
/* We can have new write after previous check */
offset = QEMU_ALIGN_DOWN(offset, s->cluster_size);
bytes = s->cluster_size;
nr = s->cluster_size;
ret = qcow2_get_cluster_offset(bs, offset, &nr, &off);
if (ret != QCOW2_CLUSTER_UNALLOCATED &&
ret != QCOW2_CLUSTER_ZERO_PLAIN &&
ret != QCOW2_CLUSTER_ZERO_ALLOC) {
qemu_co_mutex_unlock(&s->lock);
return -ENOTSUP;
}
} else {
qemu_co_mutex_lock(&s->lock);
}
trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, bytes);
/* Whatever is left can use real zero clusters */
ret = qcow2_cluster_zeroize(bs, offset, bytes, flags);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs,
int64_t offset, int bytes)
{
int ret;
BDRVQcow2State *s = bs->opaque;
if (!QEMU_IS_ALIGNED(offset | bytes, s->cluster_size)) {
assert(bytes < s->cluster_size);
/* Ignore partial clusters, except for the special case of the
* complete partial cluster at the end of an unaligned file */
if (!QEMU_IS_ALIGNED(offset, s->cluster_size) ||
offset + bytes != bs->total_sectors * BDRV_SECTOR_SIZE) {
return -ENOTSUP;
}
}
qemu_co_mutex_lock(&s->lock);
ret = qcow2_cluster_discard(bs, offset, bytes, QCOW2_DISCARD_REQUEST,
false);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
static int coroutine_fn
qcow2_co_copy_range_from(BlockDriverState *bs,
BdrvChild *src, uint64_t src_offset,
BdrvChild *dst, uint64_t dst_offset,
uint64_t bytes, BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags)
{
BDRVQcow2State *s = bs->opaque;
int ret;
unsigned int cur_bytes; /* number of bytes in current iteration */
BdrvChild *child = NULL;
BdrvRequestFlags cur_write_flags;
assert(!bs->encrypted);
qemu_co_mutex_lock(&s->lock);
while (bytes != 0) {
uint64_t copy_offset = 0;
/* prepare next request */
cur_bytes = MIN(bytes, INT_MAX);
cur_write_flags = write_flags;
ret = qcow2_get_cluster_offset(bs, src_offset, &cur_bytes, &copy_offset);
if (ret < 0) {
goto out;
}
switch (ret) {
case QCOW2_CLUSTER_UNALLOCATED:
if (bs->backing && bs->backing->bs) {
int64_t backing_length = bdrv_getlength(bs->backing->bs);
if (src_offset >= backing_length) {
cur_write_flags |= BDRV_REQ_ZERO_WRITE;
} else {
child = bs->backing;
cur_bytes = MIN(cur_bytes, backing_length - src_offset);
copy_offset = src_offset;
}
} else {
cur_write_flags |= BDRV_REQ_ZERO_WRITE;
}
break;
case QCOW2_CLUSTER_ZERO_PLAIN:
case QCOW2_CLUSTER_ZERO_ALLOC:
cur_write_flags |= BDRV_REQ_ZERO_WRITE;
break;
case QCOW2_CLUSTER_COMPRESSED:
ret = -ENOTSUP;
goto out;
case QCOW2_CLUSTER_NORMAL:
child = s->data_file;
copy_offset += offset_into_cluster(s, src_offset);
if ((copy_offset & 511) != 0) {
ret = -EIO;
goto out;
}
break;
default:
abort();
}
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_copy_range_from(child,
copy_offset,
dst, dst_offset,
cur_bytes, read_flags, cur_write_flags);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
goto out;
}
bytes -= cur_bytes;
src_offset += cur_bytes;
dst_offset += cur_bytes;
}
ret = 0;
out:
qemu_co_mutex_unlock(&s->lock);
return ret;
}
static int coroutine_fn
qcow2_co_copy_range_to(BlockDriverState *bs,
BdrvChild *src, uint64_t src_offset,
BdrvChild *dst, uint64_t dst_offset,
uint64_t bytes, BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags)
{
BDRVQcow2State *s = bs->opaque;
int offset_in_cluster;
int ret;
unsigned int cur_bytes; /* number of sectors in current iteration */
uint64_t cluster_offset;
QCowL2Meta *l2meta = NULL;
assert(!bs->encrypted);
qemu_co_mutex_lock(&s->lock);
while (bytes != 0) {
l2meta = NULL;
offset_in_cluster = offset_into_cluster(s, dst_offset);
cur_bytes = MIN(bytes, INT_MAX);
/* TODO:
* If src->bs == dst->bs, we could simply copy by incrementing
* the refcnt, without copying user data.
* Or if src->bs == dst->bs->backing->bs, we could copy by discarding. */
ret = qcow2_alloc_cluster_offset(bs, dst_offset, &cur_bytes,
&cluster_offset, &l2meta);
if (ret < 0) {
goto fail;
}
assert((cluster_offset & 511) == 0);
ret = qcow2_pre_write_overlap_check(bs, 0,
cluster_offset + offset_in_cluster, cur_bytes, true);
if (ret < 0) {
goto fail;
}
qemu_co_mutex_unlock(&s->lock);
ret = bdrv_co_copy_range_to(src, src_offset,
s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, read_flags, write_flags);
qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
goto fail;
}
ret = qcow2_handle_l2meta(bs, &l2meta, true);
if (ret) {
goto fail;
}
bytes -= cur_bytes;
src_offset += cur_bytes;
dst_offset += cur_bytes;
}
ret = 0;
fail:
qcow2_handle_l2meta(bs, &l2meta, false);
qemu_co_mutex_unlock(&s->lock);
trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
return ret;
}
static int coroutine_fn qcow2_co_truncate(BlockDriverState *bs, int64_t offset,
PreallocMode prealloc, Error **errp)
{
BDRVQcow2State *s = bs->opaque;
uint64_t old_length;
int64_t new_l1_size;
int ret;
QDict *options;
if (prealloc != PREALLOC_MODE_OFF && prealloc != PREALLOC_MODE_METADATA &&
prealloc != PREALLOC_MODE_FALLOC && prealloc != PREALLOC_MODE_FULL)
{
error_setg(errp, "Unsupported preallocation mode '%s'",
PreallocMode_str(prealloc));
return -ENOTSUP;
}
if (offset & 511) {
error_setg(errp, "The new size must be a multiple of 512");
return -EINVAL;
}
qemu_co_mutex_lock(&s->lock);
/* cannot proceed if image has snapshots */
if (s->nb_snapshots) {
error_setg(errp, "Can't resize an image which has snapshots");
ret = -ENOTSUP;
goto fail;
}
/* cannot proceed if image has bitmaps */
if (qcow2_truncate_bitmaps_check(bs, errp)) {
ret = -ENOTSUP;
goto fail;
}
old_length = bs->total_sectors * BDRV_SECTOR_SIZE;
new_l1_size = size_to_l1(s, offset);
if (offset < old_length) {
int64_t last_cluster, old_file_size;
if (prealloc != PREALLOC_MODE_OFF) {
error_setg(errp,
"Preallocation can't be used for shrinking an image");
ret = -EINVAL;
goto fail;
}
ret = qcow2_cluster_discard(bs, ROUND_UP(offset, s->cluster_size),
old_length - ROUND_UP(offset,
s->cluster_size),
QCOW2_DISCARD_ALWAYS, true);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to discard cropped clusters");
goto fail;
}
ret = qcow2_shrink_l1_table(bs, new_l1_size);
if (ret < 0) {
error_setg_errno(errp, -ret,
"Failed to reduce the number of L2 tables");
goto fail;
}
ret = qcow2_shrink_reftable(bs);
if (ret < 0) {
error_setg_errno(errp, -ret,
"Failed to discard unused refblocks");
goto fail;
}
old_file_size = bdrv_getlength(bs->file->bs);
if (old_file_size < 0) {
error_setg_errno(errp, -old_file_size,
"Failed to inquire current file length");
ret = old_file_size;
goto fail;
}
last_cluster = qcow2_get_last_cluster(bs, old_file_size);
if (last_cluster < 0) {
error_setg_errno(errp, -last_cluster,
"Failed to find the last cluster");
ret = last_cluster;
goto fail;
}
if ((last_cluster + 1) * s->cluster_size < old_file_size) {
Error *local_err = NULL;
bdrv_co_truncate(bs->file, (last_cluster + 1) * s->cluster_size,
PREALLOC_MODE_OFF, &local_err);
if (local_err) {
warn_reportf_err(local_err,
"Failed to truncate the tail of the image: ");
}
}
} else {
ret = qcow2_grow_l1_table(bs, new_l1_size, true);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to grow the L1 table");
goto fail;
}
}
switch (prealloc) {
case PREALLOC_MODE_OFF:
if (has_data_file(bs)) {
ret = bdrv_co_truncate(s->data_file, offset, prealloc, errp);
if (ret < 0) {
goto fail;
}
}
break;
case PREALLOC_MODE_METADATA:
ret = preallocate_co(bs, old_length, offset, prealloc, errp);
if (ret < 0) {
goto fail;
}
break;
case PREALLOC_MODE_FALLOC:
case PREALLOC_MODE_FULL:
{
int64_t allocation_start, host_offset, guest_offset;
int64_t clusters_allocated;
int64_t old_file_size, new_file_size;
uint64_t nb_new_data_clusters, nb_new_l2_tables;
/* With a data file, preallocation means just allocating the metadata
* and forwarding the truncate request to the data file */
if (has_data_file(bs)) {
ret = preallocate_co(bs, old_length, offset, prealloc, errp);
if (ret < 0) {
goto fail;
}
break;
}
old_file_size = bdrv_getlength(bs->file->bs);
if (old_file_size < 0) {
error_setg_errno(errp, -old_file_size,
"Failed to inquire current file length");
ret = old_file_size;
goto fail;
}
old_file_size = ROUND_UP(old_file_size, s->cluster_size);
nb_new_data_clusters = DIV_ROUND_UP(offset - old_length,
s->cluster_size);
/* This is an overestimation; we will not actually allocate space for
* these in the file but just make sure the new refcount structures are
* able to cover them so we will not have to allocate new refblocks
* while entering the data blocks in the potentially new L2 tables.
* (We do not actually care where the L2 tables are placed. Maybe they
* are already allocated or they can be placed somewhere before
* @old_file_size. It does not matter because they will be fully
* allocated automatically, so they do not need to be covered by the
* preallocation. All that matters is that we will not have to allocate
* new refcount structures for them.) */
nb_new_l2_tables = DIV_ROUND_UP(nb_new_data_clusters,
s->cluster_size / sizeof(uint64_t));
/* The cluster range may not be aligned to L2 boundaries, so add one L2
* table for a potential head/tail */
nb_new_l2_tables++;
allocation_start = qcow2_refcount_area(bs, old_file_size,
nb_new_data_clusters +
nb_new_l2_tables,
true, 0, 0);
if (allocation_start < 0) {
error_setg_errno(errp, -allocation_start,
"Failed to resize refcount structures");
ret = allocation_start;
goto fail;
}
clusters_allocated = qcow2_alloc_clusters_at(bs, allocation_start,
nb_new_data_clusters);
if (clusters_allocated < 0) {
error_setg_errno(errp, -clusters_allocated,
"Failed to allocate data clusters");
ret = clusters_allocated;
goto fail;
}
assert(clusters_allocated == nb_new_data_clusters);
/* Allocate the data area */
new_file_size = allocation_start +
nb_new_data_clusters * s->cluster_size;
ret = bdrv_co_truncate(bs->file, new_file_size, prealloc, errp);
if (ret < 0) {
error_prepend(errp, "Failed to resize underlying file: ");
qcow2_free_clusters(bs, allocation_start,
nb_new_data_clusters * s->cluster_size,
QCOW2_DISCARD_OTHER);
goto fail;
}
/* Create the necessary L2 entries */
host_offset = allocation_start;
guest_offset = old_length;
while (nb_new_data_clusters) {
int64_t nb_clusters = MIN(
nb_new_data_clusters,
s->l2_slice_size - offset_to_l2_slice_index(s, guest_offset));
QCowL2Meta allocation = {
.offset = guest_offset,
.alloc_offset = host_offset,
.nb_clusters = nb_clusters,
};
qemu_co_queue_init(&allocation.dependent_requests);
ret = qcow2_alloc_cluster_link_l2(bs, &allocation);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to update L2 tables");
qcow2_free_clusters(bs, host_offset,
nb_new_data_clusters * s->cluster_size,
QCOW2_DISCARD_OTHER);
goto fail;
}
guest_offset += nb_clusters * s->cluster_size;
host_offset += nb_clusters * s->cluster_size;
nb_new_data_clusters -= nb_clusters;
}
break;
}
default:
g_assert_not_reached();
}
if (prealloc != PREALLOC_MODE_OFF) {
/* Flush metadata before actually changing the image size */
ret = qcow2_write_caches(bs);
if (ret < 0) {
error_setg_errno(errp, -ret,
"Failed to flush the preallocated area to disk");
goto fail;
}
}
bs->total_sectors = offset / BDRV_SECTOR_SIZE;
/* write updated header.size */
offset = cpu_to_be64(offset);
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
&offset, sizeof(uint64_t));
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to update the image size");
goto fail;
}
s->l1_vm_state_index = new_l1_size;
/* Update cache sizes */
options = qdict_clone_shallow(bs->options);
ret = qcow2_update_options(bs, options, s->flags, errp);
qobject_unref(options);
if (ret < 0) {
goto fail;
}
ret = 0;
fail:
qemu_co_mutex_unlock(&s->lock);
return ret;
}
/* XXX: put compressed sectors first, then all the cluster aligned
tables to avoid losing bytes in alignment */
static coroutine_fn int
qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov)
{
BDRVQcow2State *s = bs->opaque;
int ret;
ssize_t out_len;
uint8_t *buf, *out_buf;
uint64_t cluster_offset;
if (has_data_file(bs)) {
return -ENOTSUP;
}
if (bytes == 0) {
/* align end of file to a sector boundary to ease reading with
sector based I/Os */
int64_t len = bdrv_getlength(bs->file->bs);
if (len < 0) {
return len;
}
return bdrv_co_truncate(bs->file, len, PREALLOC_MODE_OFF, NULL);
}
if (offset_into_cluster(s, offset)) {
return -EINVAL;
}
buf = qemu_blockalign(bs, s->cluster_size);
if (bytes != s->cluster_size) {
if (bytes > s->cluster_size ||
offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
{
qemu_vfree(buf);
return -EINVAL;
}
/* Zero-pad last write if image size is not cluster aligned */
memset(buf + bytes, 0, s->cluster_size - bytes);
}
qemu_iovec_to_buf(qiov, 0, buf, bytes);
out_buf = g_malloc(s->cluster_size);
out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1,
buf, s->cluster_size);
if (out_len == -ENOMEM) {
/* could not compress: write normal cluster */
ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0);
if (ret < 0) {
goto fail;
}
goto success;
} else if (out_len < 0) {
ret = -EINVAL;
goto fail;
}
qemu_co_mutex_lock(&s->lock);
ret = qcow2_alloc_compressed_cluster_offset(bs, offset, out_len,
&cluster_offset);
if (ret < 0) {
qemu_co_mutex_unlock(&s->lock);
goto fail;
}
ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len, true);
qemu_co_mutex_unlock(&s->lock);
if (ret < 0) {
goto fail;
}
BLKDBG_EVENT(s->data_file, BLKDBG_WRITE_COMPRESSED);
ret = bdrv_co_pwrite(s->data_file, cluster_offset, out_len, out_buf, 0);
if (ret < 0) {
goto fail;
}
success:
ret = 0;
fail:
qemu_vfree(buf);
g_free(out_buf);
return ret;
}
static int coroutine_fn
qcow2_co_preadv_compressed(BlockDriverState *bs,
uint64_t file_cluster_offset,
uint64_t offset,
uint64_t bytes,
QEMUIOVector *qiov)
{
BDRVQcow2State *s = bs->opaque;
int ret = 0, csize, nb_csectors;
uint64_t coffset;
uint8_t *buf, *out_buf;
int offset_in_cluster = offset_into_cluster(s, offset);
coffset = file_cluster_offset & s->cluster_offset_mask;
nb_csectors = ((file_cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE -
(coffset & ~QCOW2_COMPRESSED_SECTOR_MASK);
buf = g_try_malloc(csize);
if (!buf) {
return -ENOMEM;
}
out_buf = qemu_blockalign(bs, s->cluster_size);
BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
ret = bdrv_co_pread(bs->file, coffset, csize, buf, 0);
if (ret < 0) {
goto fail;
}
if (qcow2_co_decompress(bs, out_buf, s->cluster_size, buf, csize) < 0) {
ret = -EIO;
goto fail;
}
qemu_iovec_from_buf(qiov, 0, out_buf + offset_in_cluster, bytes);
fail:
qemu_vfree(out_buf);
g_free(buf);
return ret;
}
static int make_completely_empty(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
Error *local_err = NULL;
int ret, l1_clusters;
int64_t offset;
uint64_t *new_reftable = NULL;
uint64_t rt_entry, l1_size2;
struct {
uint64_t l1_offset;
uint64_t reftable_offset;
uint32_t reftable_clusters;
} QEMU_PACKED l1_ofs_rt_ofs_cls;
ret = qcow2_cache_empty(bs, s->l2_table_cache);
if (ret < 0) {
goto fail;
}
ret = qcow2_cache_empty(bs, s->refcount_block_cache);
if (ret < 0) {
goto fail;
}
/* Refcounts will be broken utterly */
ret = qcow2_mark_dirty(bs);
if (ret < 0) {
goto fail;
}
BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t);
/* After this call, neither the in-memory nor the on-disk refcount
* information accurately describe the actual references */
ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset,
l1_clusters * s->cluster_size, 0);
if (ret < 0) {
goto fail_broken_refcounts;
}
memset(s->l1_table, 0, l1_size2);
BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE);
/* Overwrite enough clusters at the beginning of the sectors to place
* the refcount table, a refcount block and the L1 table in; this may
* overwrite parts of the existing refcount and L1 table, which is not
* an issue because the dirty flag is set, complete data loss is in fact
* desired and partial data loss is consequently fine as well */
ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size,
(2 + l1_clusters) * s->cluster_size, 0);
/* This call (even if it failed overall) may have overwritten on-disk
* refcount structures; in that case, the in-memory refcount information
* will probably differ from the on-disk information which makes the BDS
* unusable */
if (ret < 0) {
goto fail_broken_refcounts;
}
BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE);
/* "Create" an empty reftable (one cluster) directly after the image
* header and an empty L1 table three clusters after the image header;
* the cluster between those two will be used as the first refblock */
l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size);
l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size);
l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1);
ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset),
&l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls));
if (ret < 0) {
goto fail_broken_refcounts;
}
s->l1_table_offset = 3 * s->cluster_size;
new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t));
if (!new_reftable) {
ret = -ENOMEM;
goto fail_broken_refcounts;
}
s->refcount_table_offset = s->cluster_size;
s->refcount_table_size = s->cluster_size / sizeof(uint64_t);
s->max_refcount_table_index = 0;
g_free(s->refcount_table);
s->refcount_table = new_reftable;
new_reftable = NULL;
/* Now the in-memory refcount information again corresponds to the on-disk
* information (reftable is empty and no refblocks (the refblock cache is
* empty)); however, this means some clusters (e.g. the image header) are
* referenced, but not refcounted, but the normal qcow2 code assumes that
* the in-memory information is always correct */
BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
/* Enter the first refblock into the reftable */
rt_entry = cpu_to_be64(2 * s->cluster_size);
ret = bdrv_pwrite_sync(bs->file, s->cluster_size,
&rt_entry, sizeof(rt_entry));
if (ret < 0) {
goto fail_broken_refcounts;
}
s->refcount_table[0] = 2 * s->cluster_size;
s->free_cluster_index = 0;
assert(3 + l1_clusters <= s->refcount_block_size);
offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2);
if (offset < 0) {
ret = offset;
goto fail_broken_refcounts;
} else if (offset > 0) {
error_report("First cluster in emptied image is in use");
abort();
}
/* Now finally the in-memory information corresponds to the on-disk
* structures and is correct */
ret = qcow2_mark_clean(bs);
if (ret < 0) {
goto fail;
}
ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size,
PREALLOC_MODE_OFF, &local_err);
if (ret < 0) {
error_report_err(local_err);
goto fail;
}
return 0;
fail_broken_refcounts:
/* The BDS is unusable at this point. If we wanted to make it usable, we
* would have to call qcow2_refcount_close(), qcow2_refcount_init(),
* qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
* again. However, because the functions which could have caused this error
* path to be taken are used by those functions as well, it's very likely
* that that sequence will fail as well. Therefore, just eject the BDS. */
bs->drv = NULL;
fail:
g_free(new_reftable);
return ret;
}
static int qcow2_make_empty(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
uint64_t offset, end_offset;
int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size);
int l1_clusters, ret = 0;
l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
if (s->qcow_version >= 3 && !s->snapshots && !s->nb_bitmaps &&
3 + l1_clusters <= s->refcount_block_size &&
s->crypt_method_header != QCOW_CRYPT_LUKS &&
!has_data_file(bs)) {
/* The following function only works for qcow2 v3 images (it
* requires the dirty flag) and only as long as there are no
* features that reserve extra clusters (such as snapshots,
* LUKS header, or persistent bitmaps), because it completely
* empties the image. Furthermore, the L1 table and three
* additional clusters (image header, refcount table, one
* refcount block) have to fit inside one refcount block. It
* only resets the image file, i.e. does not work with an
* external data file. */
return make_completely_empty(bs);
}
/* This fallback code simply discards every active cluster; this is slow,
* but works in all cases */
end_offset = bs->total_sectors * BDRV_SECTOR_SIZE;
for (offset = 0; offset < end_offset; offset += step) {
/* As this function is generally used after committing an external
* snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
* default action for this kind of discard is to pass the discard,
* which will ideally result in an actually smaller image file, as
* is probably desired. */
ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset),
QCOW2_DISCARD_SNAPSHOT, true);
if (ret < 0) {
break;
}
}
return ret;
}
static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
int ret;
qemu_co_mutex_lock(&s->lock);
ret = qcow2_write_caches(bs);
qemu_co_mutex_unlock(&s->lock);
return ret;
}
static ssize_t qcow2_measure_crypto_hdr_init_func(QCryptoBlock *block,
size_t headerlen, void *opaque, Error **errp)
{
size_t *headerlenp = opaque;
/* Stash away the payload size */
*headerlenp = headerlen;
return 0;
}
static ssize_t qcow2_measure_crypto_hdr_write_func(QCryptoBlock *block,
size_t offset, const uint8_t *buf, size_t buflen,
void *opaque, Error **errp)
{
/* Discard the bytes, we're not actually writing to an image */
return buflen;
}
/* Determine the number of bytes for the LUKS payload */
static bool qcow2_measure_luks_headerlen(QemuOpts *opts, size_t *len,
Error **errp)
{
QDict *opts_qdict;
QDict *cryptoopts_qdict;
QCryptoBlockCreateOptions *cryptoopts;
QCryptoBlock *crypto;
/* Extract "encrypt." options into a qdict */
opts_qdict = qemu_opts_to_qdict(opts, NULL);
qdict_extract_subqdict(opts_qdict, &cryptoopts_qdict, "encrypt.");
qobject_unref(opts_qdict);
/* Build QCryptoBlockCreateOptions object from qdict */
qdict_put_str(cryptoopts_qdict, "format", "luks");
cryptoopts = block_crypto_create_opts_init(cryptoopts_qdict, errp);
qobject_unref(cryptoopts_qdict);
if (!cryptoopts) {
return false;
}
/* Fake LUKS creation in order to determine the payload size */
crypto = qcrypto_block_create(cryptoopts, "encrypt.",
qcow2_measure_crypto_hdr_init_func,
qcow2_measure_crypto_hdr_write_func,
len, errp);
qapi_free_QCryptoBlockCreateOptions(cryptoopts);
if (!crypto) {
return false;
}
qcrypto_block_free(crypto);
return true;
}
static BlockMeasureInfo *qcow2_measure(QemuOpts *opts, BlockDriverState *in_bs,
Error **errp)
{
Error *local_err = NULL;
BlockMeasureInfo *info;
uint64_t required = 0; /* bytes that contribute to required size */
uint64_t virtual_size; /* disk size as seen by guest */
uint64_t refcount_bits;
uint64_t l2_tables;
uint64_t luks_payload_size = 0;
size_t cluster_size;
int version;
char *optstr;
PreallocMode prealloc;
bool has_backing_file;
bool has_luks;
/* Parse image creation options */
cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err);
if (local_err) {
goto err;
}
version = qcow2_opt_get_version_del(opts, &local_err);
if (local_err) {
goto err;
}
refcount_bits = qcow2_opt_get_refcount_bits_del(opts, version, &local_err);
if (local_err) {
goto err;
}
optstr = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
prealloc = qapi_enum_parse(&PreallocMode_lookup, optstr,
PREALLOC_MODE_OFF, &local_err);
g_free(optstr);
if (local_err) {
goto err;
}
optstr = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
has_backing_file = !!optstr;
g_free(optstr);
optstr = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT);
has_luks = optstr && strcmp(optstr, "luks") == 0;
g_free(optstr);
if (has_luks) {
size_t headerlen;
if (!qcow2_measure_luks_headerlen(opts, &headerlen, &local_err)) {
goto err;
}
luks_payload_size = ROUND_UP(headerlen, cluster_size);
}
virtual_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
virtual_size = ROUND_UP(virtual_size, cluster_size);
/* Check that virtual disk size is valid */
l2_tables = DIV_ROUND_UP(virtual_size / cluster_size,
cluster_size / sizeof(uint64_t));
if (l2_tables * sizeof(uint64_t) > QCOW_MAX_L1_SIZE) {
error_setg(&local_err, "The image size is too large "
"(try using a larger cluster size)");
goto err;
}
/* Account for input image */
if (in_bs) {
int64_t ssize = bdrv_getlength(in_bs);
if (ssize < 0) {
error_setg_errno(&local_err, -ssize,
"Unable to get image virtual_size");
goto err;
}
virtual_size = ROUND_UP(ssize, cluster_size);
if (has_backing_file) {
/* We don't how much of the backing chain is shared by the input
* image and the new image file. In the worst case the new image's
* backing file has nothing in common with the input image. Be
* conservative and assume all clusters need to be written.
*/
required = virtual_size;
} else {
int64_t offset;
int64_t pnum = 0;
for (offset = 0; offset < ssize; offset += pnum) {
int ret;
ret = bdrv_block_status_above(in_bs, NULL, offset,
ssize - offset, &pnum, NULL,
NULL);
if (ret < 0) {
error_setg_errno(&local_err, -ret,
"Unable to get block status");
goto err;
}
if (ret & BDRV_BLOCK_ZERO) {
/* Skip zero regions (safe with no backing file) */
} else if ((ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) ==
(BDRV_BLOCK_DATA | BDRV_BLOCK_ALLOCATED)) {
/* Extend pnum to end of cluster for next iteration */
pnum = ROUND_UP(offset + pnum, cluster_size) - offset;
/* Count clusters we've seen */
required += offset % cluster_size + pnum;
}
}
}
}
/* Take into account preallocation. Nothing special is needed for
* PREALLOC_MODE_METADATA since metadata is always counted.
*/
if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
required = virtual_size;
}
info = g_new(BlockMeasureInfo, 1);
info->fully_allocated =
qcow2_calc_prealloc_size(virtual_size, cluster_size,
ctz32(refcount_bits)) + luks_payload_size;
/* Remove data clusters that are not required. This overestimates the
* required size because metadata needed for the fully allocated file is
* still counted.
*/
info->required = info->fully_allocated - virtual_size + required;
return info;
err:
error_propagate(errp, local_err);
return NULL;
}
static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVQcow2State *s = bs->opaque;
bdi->unallocated_blocks_are_zero = true;
bdi->cluster_size = s->cluster_size;
bdi->vm_state_offset = qcow2_vm_state_offset(s);
return 0;
}
static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
ImageInfoSpecific *spec_info;
QCryptoBlockInfo *encrypt_info = NULL;
Error *local_err = NULL;
if (s->crypto != NULL) {
encrypt_info = qcrypto_block_get_info(s->crypto, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return NULL;
}
}
spec_info = g_new(ImageInfoSpecific, 1);
*spec_info = (ImageInfoSpecific){
.type = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
.u.qcow2.data = g_new0(ImageInfoSpecificQCow2, 1),
};
if (s->qcow_version == 2) {
*spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
.compat = g_strdup("0.10"),
.refcount_bits = s->refcount_bits,
};
} else if (s->qcow_version == 3) {
Qcow2BitmapInfoList *bitmaps;
bitmaps = qcow2_get_bitmap_info_list(bs, &local_err);
if (local_err) {
error_propagate(errp, local_err);
qapi_free_ImageInfoSpecific(spec_info);
return NULL;
}
*spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
.compat = g_strdup("1.1"),
.lazy_refcounts = s->compatible_features &
QCOW2_COMPAT_LAZY_REFCOUNTS,
.has_lazy_refcounts = true,
.corrupt = s->incompatible_features &
QCOW2_INCOMPAT_CORRUPT,
.has_corrupt = true,
.refcount_bits = s->refcount_bits,
.has_bitmaps = !!bitmaps,
.bitmaps = bitmaps,
.has_data_file = !!s->image_data_file,
.data_file = g_strdup(s->image_data_file),
.has_data_file_raw = has_data_file(bs),
.data_file_raw = data_file_is_raw(bs),
};
} else {
/* if this assertion fails, this probably means a new version was
* added without having it covered here */
assert(false);
}
if (encrypt_info) {
ImageInfoSpecificQCow2Encryption *qencrypt =
g_new(ImageInfoSpecificQCow2Encryption, 1);
switch (encrypt_info->format) {
case Q_CRYPTO_BLOCK_FORMAT_QCOW:
qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_AES;
break;
case Q_CRYPTO_BLOCK_FORMAT_LUKS:
qencrypt->format = BLOCKDEV_QCOW2_ENCRYPTION_FORMAT_LUKS;
qencrypt->u.luks = encrypt_info->u.luks;
break;
default:
abort();
}
/* Since we did shallow copy above, erase any pointers
* in the original info */
memset(&encrypt_info->u, 0, sizeof(encrypt_info->u));
qapi_free_QCryptoBlockInfo(encrypt_info);
spec_info->u.qcow2.data->has_encrypt = true;
spec_info->u.qcow2.data->encrypt = qencrypt;
}
return spec_info;
}
static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
int64_t pos)
{
BDRVQcow2State *s = bs->opaque;
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos,
qiov->size, qiov, 0);
}
static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
int64_t pos)
{
BDRVQcow2State *s = bs->opaque;
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos,
qiov->size, qiov, 0);
}
/*
* Downgrades an image's version. To achieve this, any incompatible features
* have to be removed.
*/
static int qcow2_downgrade(BlockDriverState *bs, int target_version,
BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
int current_version = s->qcow_version;
int ret;
/* This is qcow2_downgrade(), not qcow2_upgrade() */
assert(target_version < current_version);
/* There are no other versions (now) that you can downgrade to */
assert(target_version == 2);
if (s->refcount_order != 4) {
error_setg(errp, "compat=0.10 requires refcount_bits=16");
return -ENOTSUP;
}
if (has_data_file(bs)) {
error_setg(errp, "Cannot downgrade an image with a data file");
return -ENOTSUP;
}
/* clear incompatible features */
if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
ret = qcow2_mark_clean(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to make the image clean");
return ret;
}
}
/* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
* the first place; if that happens nonetheless, returning -ENOTSUP is the
* best thing to do anyway */
if (s->incompatible_features) {
error_setg(errp, "Cannot downgrade an image with incompatible features "
"%#" PRIx64 " set", s->incompatible_features);
return -ENOTSUP;
}
/* since we can ignore compatible features, we can set them to 0 as well */
s->compatible_features = 0;
/* if lazy refcounts have been used, they have already been fixed through
* clearing the dirty flag */
/* clearing autoclear features is trivial */
s->autoclear_features = 0;
ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to turn zero into data clusters");
return ret;
}
s->qcow_version = target_version;
ret = qcow2_update_header(bs);
if (ret < 0) {
s->qcow_version = current_version;
error_setg_errno(errp, -ret, "Failed to update the image header");
return ret;
}
return 0;
}
typedef enum Qcow2AmendOperation {
/* This is the value Qcow2AmendHelperCBInfo::last_operation will be
* statically initialized to so that the helper CB can discern the first
* invocation from an operation change */
QCOW2_NO_OPERATION = 0,
QCOW2_CHANGING_REFCOUNT_ORDER,
QCOW2_DOWNGRADING,
} Qcow2AmendOperation;
typedef struct Qcow2AmendHelperCBInfo {
/* The code coordinating the amend operations should only modify
* these four fields; the rest will be managed by the CB */
BlockDriverAmendStatusCB *original_status_cb;
void *original_cb_opaque;
Qcow2AmendOperation current_operation;
/* Total number of operations to perform (only set once) */
int total_operations;
/* The following fields are managed by the CB */
/* Number of operations completed */
int operations_completed;
/* Cumulative offset of all completed operations */
int64_t offset_completed;
Qcow2AmendOperation last_operation;
int64_t last_work_size;
} Qcow2AmendHelperCBInfo;
static void qcow2_amend_helper_cb(BlockDriverState *bs,
int64_t operation_offset,
int64_t operation_work_size, void *opaque)
{
Qcow2AmendHelperCBInfo *info = opaque;
int64_t current_work_size;
int64_t projected_work_size;
if (info->current_operation != info->last_operation) {
if (info->last_operation != QCOW2_NO_OPERATION) {
info->offset_completed += info->last_work_size;
info->operations_completed++;
}
info->last_operation = info->current_operation;
}
assert(info->total_operations > 0);
assert(info->operations_completed < info->total_operations);
info->last_work_size = operation_work_size;
current_work_size = info->offset_completed + operation_work_size;
/* current_work_size is the total work size for (operations_completed + 1)
* operations (which includes this one), so multiply it by the number of
* operations not covered and divide it by the number of operations
* covered to get a projection for the operations not covered */
projected_work_size = current_work_size * (info->total_operations -
info->operations_completed - 1)
/ (info->operations_completed + 1);
info->original_status_cb(bs, info->offset_completed + operation_offset,
current_work_size + projected_work_size,
info->original_cb_opaque);
}
static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
BlockDriverAmendStatusCB *status_cb,
void *cb_opaque,
Error **errp)
{
BDRVQcow2State *s = bs->opaque;
int old_version = s->qcow_version, new_version = old_version;
uint64_t new_size = 0;
const char *backing_file = NULL, *backing_format = NULL, *data_file = NULL;
bool lazy_refcounts = s->use_lazy_refcounts;
bool data_file_raw = data_file_is_raw(bs);
const char *compat = NULL;
uint64_t cluster_size = s->cluster_size;
bool encrypt;
int encformat;
int refcount_bits = s->refcount_bits;
int ret;
QemuOptDesc *desc = opts->list->desc;
Qcow2AmendHelperCBInfo helper_cb_info;
while (desc && desc->name) {
if (!qemu_opt_find(opts, desc->name)) {
/* only change explicitly defined options */
desc++;
continue;
}
if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) {
compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL);
if (!compat) {
/* preserve default */
} else if (!strcmp(compat, "0.10")) {
new_version = 2;
} else if (!strcmp(compat, "1.1")) {
new_version = 3;
} else {
error_setg(errp, "Unknown compatibility level %s", compat);
return -EINVAL;
}
} else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) {
error_setg(errp, "Cannot change preallocation mode");
return -ENOTSUP;
} else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) {
new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
} else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) {
backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
} else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
} else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) {
encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT,
!!s->crypto);
if (encrypt != !!s->crypto) {
error_setg(errp,
"Changing the encryption flag is not supported");
return -ENOTSUP;
}
} else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT_FORMAT)) {
encformat = qcow2_crypt_method_from_format(
qemu_opt_get(opts, BLOCK_OPT_ENCRYPT_FORMAT));
if (encformat != s->crypt_method_header) {
error_setg(errp,
"Changing the encryption format is not supported");
return -ENOTSUP;
}
} else if (g_str_has_prefix(desc->name, "encrypt.")) {
error_setg(errp,
"Changing the encryption parameters is not supported");
return -ENOTSUP;
} else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) {
cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE,
cluster_size);
if (cluster_size != s->cluster_size) {
error_setg(errp, "Changing the cluster size is not supported");
return -ENOTSUP;
}
} else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
lazy_refcounts);
} else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) {
refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS,
refcount_bits);
if (refcount_bits <= 0 || refcount_bits > 64 ||
!is_power_of_2(refcount_bits))
{
error_setg(errp, "Refcount width must be a power of two and "
"may not exceed 64 bits");
return -EINVAL;
}
} else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE)) {
data_file = qemu_opt_get(opts, BLOCK_OPT_DATA_FILE);
if (data_file && !has_data_file(bs)) {
error_setg(errp, "data-file can only be set for images that "
"use an external data file");
return -EINVAL;
}
} else if (!strcmp(desc->name, BLOCK_OPT_DATA_FILE_RAW)) {
data_file_raw = qemu_opt_get_bool(opts, BLOCK_OPT_DATA_FILE_RAW,
data_file_raw);
if (data_file_raw && !data_file_is_raw(bs)) {
error_setg(errp, "data-file-raw cannot be set on existing "
"images");
return -EINVAL;
}
} else {
/* if this point is reached, this probably means a new option was
* added without having it covered here */
abort();
}
desc++;
}
helper_cb_info = (Qcow2AmendHelperCBInfo){
.original_status_cb = status_cb,
.original_cb_opaque = cb_opaque,
.total_operations = (new_version < old_version)
+ (s->refcount_bits != refcount_bits)
};
/* Upgrade first (some features may require compat=1.1) */
if (new_version > old_version) {
s->qcow_version = new_version;
ret = qcow2_update_header(bs);
if (ret < 0) {
s->qcow_version = old_version;
error_setg_errno(errp, -ret, "Failed to update the image header");
return ret;
}
}
if (s->refcount_bits != refcount_bits) {
int refcount_order = ctz32(refcount_bits);
if (new_version < 3 && refcount_bits != 16) {
error_setg(errp, "Refcount widths other 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, errp);
if (ret < 0) {
return ret;
}
}
/* data-file-raw blocks backing files, so clear it first if requested */
if (data_file_raw) {
s->autoclear_features |= QCOW2_AUTOCLEAR_DATA_FILE_RAW;
} else {
s->autoclear_features &= ~QCOW2_AUTOCLEAR_DATA_FILE_RAW;
}
if (data_file) {
g_free(s->image_data_file);
s->image_data_file = *data_file ? g_strdup(data_file) : NULL;
}
ret = qcow2_update_header(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to update the image header");
return ret;
}
if (backing_file || backing_format) {
ret = qcow2_change_backing_file(bs,
backing_file ?: s->image_backing_file,
backing_format ?: s->image_backing_format);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to change the backing file");
return ret;
}
}
if (s->use_lazy_refcounts != lazy_refcounts) {
if (lazy_refcounts) {
if (new_version < 3) {
error_setg(errp, "Lazy refcounts only supported with "
"compatibility level 1.1 and above (use compat=1.1 "
"or greater)");
return -EINVAL;
}
s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
ret = qcow2_update_header(bs);
if (ret < 0) {
s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
error_setg_errno(errp, -ret, "Failed to update the image header");
return ret;
}
s->use_lazy_refcounts = true;
} else {
/* make image clean first */
ret = qcow2_mark_clean(bs);
if (ret < 0) {
error_setg_errno(errp, -ret, "Failed to make the image clean");
return ret;
}
/* now disallow lazy refcounts */
s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
ret = qcow2_update_header(bs);
if (ret < 0) {
s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
error_setg_errno(errp, -ret, "Failed to update the image header");
return ret;
}
s->use_lazy_refcounts = false;
}
}
if (new_size) {
BlockBackend *blk = blk_new(bdrv_get_aio_context(bs),
BLK_PERM_RESIZE, BLK_PERM_ALL);
ret = blk_insert_bs(blk, bs, errp);
if (ret < 0) {
blk_unref(blk);
return ret;
}
ret = blk_truncate(blk, new_size, PREALLOC_MODE_OFF, errp);
blk_unref(blk);
if (ret < 0) {
return ret;
}
}
/* Downgrade last (so unsupported features can be removed before) */
if (new_version < old_version) {
helper_cb_info.current_operation = QCOW2_DOWNGRADING;
ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb,
&helper_cb_info, errp);
if (ret < 0) {
return ret;
}
}
return 0;
}
/*
* If offset or size are negative, respectively, they will not be included in
* the BLOCK_IMAGE_CORRUPTED event emitted.
* fatal will be ignored for read-only BDS; corruptions found there will always
* be considered non-fatal.
*/
void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
int64_t size, const char *message_format, ...)
{
BDRVQcow2State *s = bs->opaque;
const char *node_name;
char *message;
va_list ap;
fatal = fatal && bdrv_is_writable(bs);
if (s->signaled_corruption &&
(!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
{
return;
}
va_start(ap, message_format);
message = g_strdup_vprintf(message_format, ap);
va_end(ap);
if (fatal) {
fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
"corruption events will be suppressed\n", message);
} else {
fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
"corruption events will be suppressed\n", message);
}
node_name = bdrv_get_node_name(bs);
qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
*node_name != '\0', node_name,
message, offset >= 0, offset,
size >= 0, size,
fatal);
g_free(message);
if (fatal) {
qcow2_mark_corrupt(bs);
bs->drv = NULL; /* make BDS unusable */
}
s->signaled_corruption = true;
}
static QemuOptsList qcow2_create_opts = {
.name = "qcow2-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_COMPAT_LEVEL,
.type = QEMU_OPT_STRING,
.help = "Compatibility level (0.10 or 1.1)"
},
{
.name = BLOCK_OPT_BACKING_FILE,
.type = QEMU_OPT_STRING,
.help = "File name of a base image"
},
{
.name = BLOCK_OPT_BACKING_FMT,
.type = QEMU_OPT_STRING,
.help = "Image format of the base image"
},
{
.name = BLOCK_OPT_DATA_FILE,
.type = QEMU_OPT_STRING,
.help = "File name of an external data file"
},
{
.name = BLOCK_OPT_DATA_FILE_RAW,
.type = QEMU_OPT_BOOL,
.help = "The external data file must stay valid as a raw image"
},
{
.name = BLOCK_OPT_ENCRYPT,
.type = QEMU_OPT_BOOL,
.help = "Encrypt the image with format 'aes'. (Deprecated "
"in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
},
{
.name = BLOCK_OPT_ENCRYPT_FORMAT,
.type = QEMU_OPT_STRING,
.help = "Encrypt the image, format choices: 'aes', 'luks'",
},
BLOCK_CRYPTO_OPT_DEF_KEY_SECRET("encrypt.",
"ID of secret providing qcow AES key or LUKS passphrase"),
BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG("encrypt."),
BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE("encrypt."),
BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG("encrypt."),
BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG("encrypt."),
BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG("encrypt."),
BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME("encrypt."),
{
.name = BLOCK_OPT_CLUSTER_SIZE,
.type = QEMU_OPT_SIZE,
.help = "qcow2 cluster size",
.def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
},
{
.name = BLOCK_OPT_PREALLOC,
.type = QEMU_OPT_STRING,
.help = "Preallocation mode (allowed values: off, metadata, "
"falloc, full)"
},
{
.name = BLOCK_OPT_LAZY_REFCOUNTS,
.type = QEMU_OPT_BOOL,
.help = "Postpone refcount updates",
.def_value_str = "off"
},
{
.name = BLOCK_OPT_REFCOUNT_BITS,
.type = QEMU_OPT_NUMBER,
.help = "Width of a reference count entry in bits",
.def_value_str = "16"
},
{ /* end of list */ }
}
};
static const char *const qcow2_strong_runtime_opts[] = {
"encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
NULL
};
BlockDriver bdrv_qcow2 = {
.format_name = "qcow2",
.instance_size = sizeof(BDRVQcow2State),
.bdrv_probe = qcow2_probe,
.bdrv_open = qcow2_open,
.bdrv_close = qcow2_close,
.bdrv_reopen_prepare = qcow2_reopen_prepare,
.bdrv_reopen_commit = qcow2_reopen_commit,
.bdrv_reopen_abort = qcow2_reopen_abort,
.bdrv_join_options = qcow2_join_options,
.bdrv_child_perm = bdrv_format_default_perms,
.bdrv_co_create_opts = qcow2_co_create_opts,
.bdrv_co_create = qcow2_co_create,
.bdrv_has_zero_init = bdrv_has_zero_init_1,
.bdrv_co_block_status = qcow2_co_block_status,
.bdrv_co_preadv = qcow2_co_preadv,
.bdrv_co_pwritev = qcow2_co_pwritev,
.bdrv_co_flush_to_os = qcow2_co_flush_to_os,
.bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes,
.bdrv_co_pdiscard = qcow2_co_pdiscard,
.bdrv_co_copy_range_from = qcow2_co_copy_range_from,
.bdrv_co_copy_range_to = qcow2_co_copy_range_to,
.bdrv_co_truncate = qcow2_co_truncate,
.bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed,
.bdrv_make_empty = qcow2_make_empty,
.bdrv_snapshot_create = qcow2_snapshot_create,
.bdrv_snapshot_goto = qcow2_snapshot_goto,
.bdrv_snapshot_delete = qcow2_snapshot_delete,
.bdrv_snapshot_list = qcow2_snapshot_list,
.bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp,
.bdrv_measure = qcow2_measure,
.bdrv_get_info = qcow2_get_info,
.bdrv_get_specific_info = qcow2_get_specific_info,
.bdrv_save_vmstate = qcow2_save_vmstate,
.bdrv_load_vmstate = qcow2_load_vmstate,
.supports_backing = true,
.bdrv_change_backing_file = qcow2_change_backing_file,
.bdrv_refresh_limits = qcow2_refresh_limits,
.bdrv_co_invalidate_cache = qcow2_co_invalidate_cache,
.bdrv_inactivate = qcow2_inactivate,
.create_opts = &qcow2_create_opts,
.strong_runtime_opts = qcow2_strong_runtime_opts,
.mutable_opts = mutable_opts,
.bdrv_co_check = qcow2_co_check,
.bdrv_amend_options = qcow2_amend_options,
.bdrv_detach_aio_context = qcow2_detach_aio_context,
.bdrv_attach_aio_context = qcow2_attach_aio_context,
.bdrv_reopen_bitmaps_rw = qcow2_reopen_bitmaps_rw,
.bdrv_can_store_new_dirty_bitmap = qcow2_can_store_new_dirty_bitmap,
.bdrv_remove_persistent_dirty_bitmap = qcow2_remove_persistent_dirty_bitmap,
};
static void bdrv_qcow2_init(void)
{
bdrv_register(&bdrv_qcow2);
}
block_init(bdrv_qcow2_init);
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