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raw_bsd: add offset and size options 

Added two new options 'offset' and 'size'. This makes it possible to use
only part of the file as a device. This can be used e.g. to limit the
access only to single partition in a disk image or use a disk inside a
tar archive (like OVA).

When 'size' is specified we do our best to honour it.

Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
master
Tomáš Golembiovský 2016-10-31 11:27:40 +01:00 committed by Kevin Wolf
parent 7eb13c9daa
commit 2fdc70452a
2 changed files with 229 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

217
block/raw_bsd.c
View File

@ -31,6 +31,30 @@
#include "qapi/error.h"
#include "qemu/option.h"
typedef struct BDRVRawState {
uint64_t offset;
uint64_t size;
bool has_size;
} BDRVRawState;
static QemuOptsList raw_runtime_opts = {
.name = "raw",
.head = QTAILQ_HEAD_INITIALIZER(raw_runtime_opts.head),
.desc = {
{
.name = "offset",
.type = QEMU_OPT_SIZE,
.help = "offset in the disk where the image starts",
},
{
.name = "size",
.type = QEMU_OPT_SIZE,
.help = "virtual disk size",
},
{ /* end of list */ }
},
};
static QemuOptsList raw_create_opts = {
.name = "raw-create-opts",
.head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
@ -44,16 +68,108 @@ static QemuOptsList raw_create_opts = {
}
};
static int raw_read_options(QDict *options, BlockDriverState *bs,
BDRVRawState *s, Error **errp)
{
Error *local_err = NULL;
QemuOpts *opts = NULL;
int64_t real_size = 0;
int ret;
real_size = bdrv_getlength(bs->file->bs);
if (real_size < 0) {
error_setg_errno(errp, -real_size, "Could not get image size");
return real_size;
}
opts = qemu_opts_create(&raw_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 end;
}
s->offset = qemu_opt_get_size(opts, "offset", 0);
if (qemu_opt_find(opts, "size") != NULL) {
s->size = qemu_opt_get_size(opts, "size", 0);
s->has_size = true;
} else {
s->has_size = false;
s->size = real_size - s->offset;
}
/* Check size and offset */
if (real_size < s->offset || (real_size - s->offset) < s->size) {
error_setg(errp, "The sum of offset (%" PRIu64 ") and size "
"(%" PRIu64 ") has to be smaller or equal to the "
" actual size of the containing file (%" PRId64 ")",
s->offset, s->size, real_size);
ret = -EINVAL;
goto end;
}
/* Make sure size is multiple of BDRV_SECTOR_SIZE to prevent rounding
* up and leaking out of the specified area. */
if (!QEMU_IS_ALIGNED(s->size, BDRV_SECTOR_SIZE)) {
error_setg(errp, "Specified size is not multiple of %llu",
BDRV_SECTOR_SIZE);
ret = -EINVAL;
goto end;
}
ret = 0;
end:
qemu_opts_del(opts);
return ret;
}
static int raw_reopen_prepare(BDRVReopenState *reopen_state,
BlockReopenQueue *queue, Error **errp)
{
return 0;
assert(reopen_state != NULL);
assert(reopen_state->bs != NULL);
reopen_state->opaque = g_new0(BDRVRawState, 1);
return raw_read_options(
reopen_state->options,
reopen_state->bs,
reopen_state->opaque,
errp);
}
static void raw_reopen_commit(BDRVReopenState *state)
{
BDRVRawState *new_s = state->opaque;
BDRVRawState *s = state->bs->opaque;
memcpy(s, new_s, sizeof(BDRVRawState));
g_free(state->opaque);
state->opaque = NULL;
}
static void raw_reopen_abort(BDRVReopenState *state)
{
g_free(state->opaque);
state->opaque = NULL;
}
static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
BDRVRawState *s = bs->opaque;
if (offset > UINT64_MAX - s->offset) {
return -EINVAL;
}
offset += s->offset;
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
}
@ -62,11 +178,23 @@ static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
BDRVRawState *s = bs->opaque;
void *buf = NULL;
BlockDriver *drv;
QEMUIOVector local_qiov;
int ret;
if (s->has_size && (offset > s->size || bytes > (s->size - offset))) {
/* There's not enough space for the data. Don't write anything and just
* fail to prevent leaking out of the size specified in options. */
return -ENOSPC;
}
if (offset > UINT64_MAX - s->offset) {
ret = -EINVAL;
goto fail;
}
if (bs->probed && offset < BLOCK_PROBE_BUF_SIZE && bytes) {
/* Handling partial writes would be a pain - so we just
* require that guests have 512-byte request alignment if
@ -101,6 +229,8 @@ static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
qiov = &local_qiov;
}
offset += s->offset;
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
@ -117,8 +247,10 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
int nb_sectors, int *pnum,
BlockDriverState **file)
{
BDRVRawState *s = bs->opaque;
*pnum = nb_sectors;
*file = bs->file->bs;
sector_num += s->offset / BDRV_SECTOR_SIZE;
return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
(sector_num << BDRV_SECTOR_BITS);
}
@ -127,18 +259,49 @@ static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int count,
BdrvRequestFlags flags)
{
BDRVRawState *s = bs->opaque;
if (offset > UINT64_MAX - s->offset) {
return -EINVAL;
}
offset += s->offset;
return bdrv_co_pwrite_zeroes(bs->file, offset, count, flags);
}
static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
int64_t offset, int count)
{
BDRVRawState *s = bs->opaque;
if (offset > UINT64_MAX - s->offset) {
return -EINVAL;
}
offset += s->offset;
return bdrv_co_pdiscard(bs->file->bs, offset, count);
}
static int64_t raw_getlength(BlockDriverState *bs)
{
return bdrv_getlength(bs->file->bs);
int64_t len;
BDRVRawState *s = bs->opaque;
/* Update size. It should not change unless the file was externally
* modified. */
len = bdrv_getlength(bs->file->bs);
if (len < 0) {
return len;
}
if (len < s->offset) {
s->size = 0;
} else {
if (s->has_size) {
/* Try to honour the size */
s->size = MIN(s->size, len - s->offset);
} else {
s->size = len - s->offset;
}
}
return s->size;
}
static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
@ -158,6 +321,18 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
static int raw_truncate(BlockDriverState *bs, int64_t offset)
{
BDRVRawState *s = bs->opaque;
if (s->has_size) {
return -ENOTSUP;
}
if (INT64_MAX - offset < s->offset) {
return -EINVAL;
}
s->size = offset;
offset += s->offset;
return bdrv_truncate(bs->file->bs, offset);
}
@ -178,6 +353,10 @@ static void raw_lock_medium(BlockDriverState *bs, bool locked)
static int raw_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
{
BDRVRawState *s = bs->opaque;
if (s->offset || s->has_size) {
return -ENOTSUP;
}
return bdrv_co_ioctl(bs->file->bs, req, buf);
}
@ -194,6 +373,9 @@ static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
static int raw_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int ret;
bs->sg = bs->file->bs->sg;
bs->supported_write_flags = BDRV_REQ_FUA &
bs->file->bs->supported_write_flags;
@ -211,6 +393,16 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
bs->file->bs->filename);
}
ret = raw_read_options(options, bs, s, errp);
if (ret < 0) {
return ret;
}
if (bs->sg && (s->offset || s->has_size)) {
error_setg(errp, "Cannot use offset/size with SCSI generic devices");
return -EINVAL;
}
return 0;
}
@ -228,18 +420,37 @@ static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
{
return bdrv_probe_blocksizes(bs->file->bs, bsz);
BDRVRawState *s = bs->opaque;
int ret;
ret = bdrv_probe_blocksizes(bs->file->bs, bsz);
if (ret < 0) {
return ret;
}
if (!QEMU_IS_ALIGNED(s->offset, MAX(bsz->log, bsz->phys))) {
return -ENOTSUP;
}
return 0;
}
static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
{
BDRVRawState *s = bs->opaque;
if (s->offset || s->has_size) {
return -ENOTSUP;
}
return bdrv_probe_geometry(bs->file->bs, geo);
}
BlockDriver bdrv_raw = {
.format_name = "raw",
.instance_size = sizeof(BDRVRawState),
.bdrv_probe = &raw_probe,
.bdrv_reopen_prepare = &raw_reopen_prepare,
.bdrv_reopen_commit = &raw_reopen_commit,
.bdrv_reopen_abort = &raw_reopen_abort,
.bdrv_open = &raw_open,
.bdrv_close = &raw_close,
.bdrv_create = &raw_create,

16
qapi/block-core.json
View File

@ -2269,6 +2269,20 @@
'*export': 'str',
'*tls-creds': 'str' } }
##
# @BlockdevOptionsRaw
#
# Driver specific block device options for the raw driver.
#
# @offset: #optional position where the block device starts
# @size: #optional the assumed size of the device
#
# Since: 2.8
##
{ 'struct': 'BlockdevOptionsRaw',
'base': 'BlockdevOptionsGenericFormat',
'data': { '*offset': 'int', '*size': 'int' } }
##
# @BlockdevOptions
#
@ -2323,7 +2337,7 @@
'qcow': 'BlockdevOptionsGenericCOWFormat',
'qed': 'BlockdevOptionsGenericCOWFormat',
'quorum': 'BlockdevOptionsQuorum',
'raw': 'BlockdevOptionsGenericFormat',
'raw': 'BlockdevOptionsRaw',
# TODO rbd: Wait for structured options
'replication':'BlockdevOptionsReplication',
# TODO sheepdog: Wait for structured options