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 <tgole...@redhat.com>
---
block/raw_bsd.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++-
qapi/block-core.json | 16 ++++-
2 files changed, 188 insertions(+), 4 deletions(-)
diff --git a/block/raw_bsd.c b/block/raw_bsd.c
index 588d408..fa53626 100644
--- a/block/raw_bsd.c
+++ b/block/raw_bsd.c
@@ -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;
+ }
+
+ /* 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);
}
@@ -138,7 +270,28 @@ static int coroutine_fn raw_co_pdiscard(BlockDriverState
*bs,
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 +311,18 @@ 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);
}
@@ -197,6 +362,8 @@ 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;
+
bs->sg = bs->file->bs->sg;
bs->supported_write_flags = BDRV_REQ_FUA &
bs->file->bs->supported_write_flags;
@@ -214,7 +381,7 @@ static int raw_open(BlockDriverState *bs, QDict *options,
int flags,
bs->file->bs->filename);
}
- return 0;
+ return raw_read_options(options, bs, s, errp);
}
static void raw_close(BlockDriverState *bs)
@@ -241,8 +408,11 @@ static int raw_probe_geometry(BlockDriverState *bs,
HDGeometry *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,
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 9d797b8..186ae75 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2224,6 +2224,20 @@
'data': { 'filename': '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
#
# Options for creating a block device. Many options are available for all
@@ -2277,7 +2291,7 @@
'qcow': 'BlockdevOptionsGenericCOWFormat',
'qed': 'BlockdevOptionsGenericCOWFormat',
'quorum': 'BlockdevOptionsQuorum',
- 'raw': 'BlockdevOptionsGenericFormat',
+ 'raw': 'BlockdevOptionsRaw',
# TODO rbd: Wait for structured options
'replication':'BlockdevOptionsReplication',
# TODO sheepdog: Wait for structured options
--
2.10.0
