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qcow2: Implement data-file-raw create option

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Provide an option to force QEMU to always keep the external data file
consistent as a standalone read-only raw image.

At the moment, this means making sure that write_zeroes requests are
forwarded to the data file instead of just updating the metadata, and
checking that no backing file is used.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2019-02-22 14:29:38 +01:00
parent 9b890bdcb6
commit 6c3944dc62
6 changed files with 109 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
block/qcow2-cluster.c
View File

@ -1783,6 +1783,16 @@ int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset,
int64_t cleared;
int ret;
/* If we have to stay in sync with an external data file, zero out
* s->data_file first. */
if (data_file_is_raw(bs)) {
assert(has_data_file(bs));
ret = bdrv_co_pwrite_zeroes(s->data_file, offset, bytes, flags);
if (ret < 0) {
return ret;
}
}
/* Caller must pass aligned values, except at image end */
assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) ||

56
block/qcow2.c
View File

@ -1498,8 +1498,14 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
"external data file");
ret = -EINVAL;
goto fail;
} else {
s->data_file = bs->file;
}
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;
}
}
@ -2606,6 +2612,12 @@ static int qcow2_change_backing_file(BlockDriverState *bs,
{
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;
}
@ -3016,6 +3028,18 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
}
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 "
@ -3072,6 +3096,10 @@ qcow2_co_create(BlockdevCreateOptions *create_options, Error **errp)
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);
@ -3253,6 +3281,7 @@ static int coroutine_fn qcow2_co_create_opts(const char *filename, QemuOpts *opt
{ 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 },
};
@ -4621,6 +4650,8 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs,
.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
@ -4825,6 +4856,7 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
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;
@ -4912,6 +4944,14 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
"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 */
@ -4958,6 +4998,13 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
}
}
/* 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;
@ -5121,6 +5168,11 @@ static QemuOptsList qcow2_create_opts = {
.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,

9
block/qcow2.h
View File

@ -225,7 +225,8 @@ enum {
QCOW2_AUTOCLEAR_BITMAPS = 1 << QCOW2_AUTOCLEAR_BITMAPS_BITNR,
QCOW2_AUTOCLEAR_DATA_FILE_RAW = 1 << QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR,
QCOW2_AUTOCLEAR_MASK = QCOW2_AUTOCLEAR_BITMAPS,
QCOW2_AUTOCLEAR_MASK = QCOW2_AUTOCLEAR_BITMAPS
| QCOW2_AUTOCLEAR_DATA_FILE_RAW,
};
enum qcow2_discard_type {
@ -474,6 +475,12 @@ static inline bool has_data_file(BlockDriverState *bs)
return (s->data_file != bs->file);
}
static inline bool data_file_is_raw(BlockDriverState *bs)
{
BDRVQcow2State *s = bs->opaque;
return !!(s->autoclear_features & QCOW2_AUTOCLEAR_DATA_FILE_RAW);
}
static inline int64_t start_of_cluster(BDRVQcow2State *s, int64_t offset)
{
return offset & ~(s->cluster_size - 1);

1
include/block/block_int.h
View File

@ -57,6 +57,7 @@
#define BLOCK_OPT_OBJECT_SIZE "object_size"
#define BLOCK_OPT_REFCOUNT_BITS "refcount_bits"
#define BLOCK_OPT_DATA_FILE "data_file"
#define BLOCK_OPT_DATA_FILE_RAW "data_file_raw"
#define BLOCK_PROBE_BUF_SIZE 512

9
qapi/block-core.json
View File

@ -62,6 +62,10 @@
# @data-file: the filename of the external data file that is stored in the
# image and used as a default for opening the image (since: 4.0)
#
# @data-file-raw: True if the external data file must stay valid as a
# standalone (read-only) raw image without looking at qcow2
# metadata (since: 4.0)
#
# @lazy-refcounts: on or off; only valid for compat >= 1.1
#
# @corrupt: true if the image has been marked corrupt; only valid for
@ -80,6 +84,7 @@
'data': {
'compat': 'str',
'*data-file': 'str',
'*data-file-raw': 'bool',
'*lazy-refcounts': 'bool',
'*corrupt': 'bool',
'refcount-bits': 'int',
@ -4144,6 +4149,9 @@
# @data-file Node to use as an external data file in which all guest
# data is stored so that only metadata remains in the qcow2
# file (since: 4.0)
# @data-file-raw True if the external data file must stay valid as a
# standalone (read-only) raw image without looking at qcow2
# metadata (default: false; since: 4.0)
# @size Size of the virtual disk in bytes
# @version Compatibility level (default: v3)
# @backing-file File name of the backing file if a backing file
@ -4160,6 +4168,7 @@
{ 'struct': 'BlockdevCreateOptionsQcow2',
'data': { 'file': 'BlockdevRef',
'*data-file': 'BlockdevRef',
'*data-file-raw': 'bool',
'size': 'size',
'*version': 'BlockdevQcow2Version',
'*backing-file': 'str',

27
tests/qemu-iotests/082.out
View File

@ -49,6 +49,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -71,6 +72,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -93,6 +95,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -115,6 +118,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -137,6 +141,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -159,6 +164,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -181,6 +187,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -203,6 +210,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -240,6 +248,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -314,6 +323,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -336,6 +346,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -358,6 +369,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -380,6 +392,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -402,6 +415,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -424,6 +438,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -446,6 +461,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -468,6 +484,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -505,6 +522,7 @@ Supported options:
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -587,6 +605,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -610,6 +629,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -633,6 +653,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -656,6 +677,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -679,6 +701,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -702,6 +725,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -725,6 +749,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -748,6 +773,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'
@ -788,6 +814,7 @@ Creation options for 'qcow2':
cluster_size=<size> - qcow2 cluster size
compat=<str> - Compatibility level (0.10 or 1.1)
data_file=<str> - File name of an external data file
data_file_raw=<bool (on/off)> - The external data file must stay valid as a raw image
encrypt.cipher-alg=<str> - Name of encryption cipher algorithm
encrypt.cipher-mode=<str> - Name of encryption cipher mode
encrypt.format=<str> - Encrypt the image, format choices: 'aes', 'luks'