qemu/block/raw-format.c
Max Reitz e61a28a9b6 block: Let format drivers pass @exact
When truncating a format node, the @exact parameter is generally handled
simply by virtue of the format storing the new size in the image
metadata.  Such formats do not need to pass on the parameter to their
file nodes.

There are exceptions, though:
- raw and crypto cannot store the image size, and thus must pass on
  @exact.

- When using qcow2 with an external data file, it just makes sense to
  keep its size in sync with the qcow2 virtual disk (because the
  external data file is the virtual disk).  Therefore, we should pass
  @exact when truncating it.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190918095144.955-7-mreitz@redhat.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2019-10-28 12:05:30 +01:00

592 lines
18 KiB
C

/* BlockDriver implementation for "raw" format driver
*
* Copyright (C) 2010-2016 Red Hat, Inc.
* Copyright (C) 2010, Blue Swirl <blauwirbel@gmail.com>
* Copyright (C) 2009, Anthony Liguori <aliguori@us.ibm.com>
*
* Author:
* Laszlo Ersek <lersek@redhat.com>
*
* 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/block_int.h"
#include "qapi/error.h"
#include "qemu/module.h"
#include "qemu/option.h"
typedef struct BDRVRawState {
uint64_t offset;
uint64_t size;
bool has_size;
} BDRVRawState;
static const char *const mutable_opts[] = { "offset", "size", NULL };
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),
.desc = {
{
.name = BLOCK_OPT_SIZE,
.type = QEMU_OPT_SIZE,
.help = "Virtual disk size"
},
{ /* end of list */ }
}
};
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 (s->offset > real_size) {
error_setg(errp, "Offset (%" PRIu64 ") cannot be greater than "
"size of the containing file (%" PRId64 ")",
s->offset, real_size);
ret = -EINVAL;
goto end;
}
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) < 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 (s->has_size && !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)
{
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;
}
/* Check and adjust the offset, against 'offset' and 'size' options. */
static inline int raw_adjust_offset(BlockDriverState *bs, uint64_t *offset,
uint64_t bytes, bool is_write)
{
BDRVRawState *s = bs->opaque;
if (s->has_size && (*offset > s->size || bytes > (s->size - *offset))) {
/* There's not enough space for the write, or the read request is
* out-of-range. Don't read/write anything to prevent leaking out of
* the size specified in options. */
return is_write ? -ENOSPC : -EINVAL;
}
if (*offset > INT64_MAX - s->offset) {
return -EINVAL;
}
*offset += s->offset;
return 0;
}
static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
int ret;
ret = raw_adjust_offset(bs, &offset, bytes, false);
if (ret) {
return ret;
}
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
}
static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
void *buf = NULL;
BlockDriver *drv;
QEMUIOVector local_qiov;
int ret;
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
* probing occurred */
QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);
assert(offset == 0 && bytes >= BLOCK_PROBE_BUF_SIZE);
buf = qemu_try_blockalign(bs->file->bs, 512);
if (!buf) {
ret = -ENOMEM;
goto fail;
}
ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
if (ret != 512) {
ret = -EINVAL;
goto fail;
}
drv = bdrv_probe_all(buf, 512, NULL);
if (drv != bs->drv) {
ret = -EPERM;
goto fail;
}
/* Use the checked buffer, a malicious guest might be overwriting its
* original buffer in the background. */
qemu_iovec_init(&local_qiov, qiov->niov + 1);
qemu_iovec_add(&local_qiov, buf, 512);
qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
qiov = &local_qiov;
}
ret = raw_adjust_offset(bs, &offset, bytes, true);
if (ret) {
goto fail;
}
BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
fail:
if (qiov == &local_qiov) {
qemu_iovec_destroy(&local_qiov);
}
qemu_vfree(buf);
return ret;
}
static int coroutine_fn raw_co_block_status(BlockDriverState *bs,
bool want_zero, int64_t offset,
int64_t bytes, int64_t *pnum,
int64_t *map,
BlockDriverState **file)
{
BDRVRawState *s = bs->opaque;
*pnum = bytes;
*file = bs->file->bs;
*map = offset + s->offset;
return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID;
}
static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int bytes,
BdrvRequestFlags flags)
{
int ret;
ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
if (ret) {
return ret;
}
return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
}
static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
int64_t offset, int bytes)
{
int ret;
ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
if (ret) {
return ret;
}
return bdrv_co_pdiscard(bs->file, offset, bytes);
}
static int64_t raw_getlength(BlockDriverState *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 BlockMeasureInfo *raw_measure(QemuOpts *opts, BlockDriverState *in_bs,
Error **errp)
{
BlockMeasureInfo *info;
int64_t required;
if (in_bs) {
required = bdrv_getlength(in_bs);
if (required < 0) {
error_setg_errno(errp, -required, "Unable to get image size");
return NULL;
}
} else {
required = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
BDRV_SECTOR_SIZE);
}
info = g_new(BlockMeasureInfo, 1);
info->required = required;
/* Unallocated sectors count towards the file size in raw images */
info->fully_allocated = info->required;
return info;
}
static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
return bdrv_get_info(bs->file->bs, bdi);
}
static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
{
if (bs->probed) {
/* To make it easier to protect the first sector, any probed
* image is restricted to read-modify-write on sub-sector
* operations. */
bs->bl.request_alignment = BDRV_SECTOR_SIZE;
}
}
static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
Error **errp)
{
BDRVRawState *s = bs->opaque;
if (s->has_size) {
error_setg(errp, "Cannot resize fixed-size raw disks");
return -ENOTSUP;
}
if (INT64_MAX - offset < s->offset) {
error_setg(errp, "Disk size too large for the chosen offset");
return -EINVAL;
}
s->size = offset;
offset += s->offset;
return bdrv_co_truncate(bs->file, offset, exact, prealloc, errp);
}
static void raw_eject(BlockDriverState *bs, bool eject_flag)
{
bdrv_eject(bs->file->bs, eject_flag);
}
static void raw_lock_medium(BlockDriverState *bs, bool locked)
{
bdrv_lock_medium(bs->file->bs, 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);
}
static int raw_has_zero_init(BlockDriverState *bs)
{
return bdrv_has_zero_init(bs->file->bs);
}
static int raw_has_zero_init_truncate(BlockDriverState *bs)
{
return bdrv_has_zero_init_truncate(bs->file->bs);
}
static int coroutine_fn raw_co_create_opts(const char *filename, QemuOpts *opts,
Error **errp)
{
return bdrv_create_file(filename, opts, errp);
}
static int raw_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVRawState *s = bs->opaque;
int ret;
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
false, errp);
if (!bs->file) {
return -EINVAL;
}
bs->sg = bs->file->bs->sg;
bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
(BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
bs->file->bs->supported_zero_flags);
if (bs->probed && !bdrv_is_read_only(bs)) {
bdrv_refresh_filename(bs->file->bs);
fprintf(stderr,
"WARNING: Image format was not specified for '%s' and probing "
"guessed raw.\n"
" Automatically detecting the format is dangerous for "
"raw images, write operations on block 0 will be restricted.\n"
" Specify the 'raw' format explicitly to remove the "
"restrictions.\n",
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;
}
static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
{
/* smallest possible positive score so that raw is used if and only if no
* other block driver works
*/
return 1;
}
static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *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);
}
static int coroutine_fn raw_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)
{
int ret;
ret = raw_adjust_offset(bs, &src_offset, bytes, false);
if (ret) {
return ret;
}
return bdrv_co_copy_range_from(bs->file, src_offset, dst, dst_offset,
bytes, read_flags, write_flags);
}
static int coroutine_fn raw_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)
{
int ret;
ret = raw_adjust_offset(bs, &dst_offset, bytes, true);
if (ret) {
return ret;
}
return bdrv_co_copy_range_to(src, src_offset, bs->file, dst_offset, bytes,
read_flags, write_flags);
}
static const char *const raw_strong_runtime_opts[] = {
"offset",
"size",
NULL
};
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_child_perm = bdrv_filter_default_perms,
.bdrv_co_create_opts = &raw_co_create_opts,
.bdrv_co_preadv = &raw_co_preadv,
.bdrv_co_pwritev = &raw_co_pwritev,
.bdrv_co_pwrite_zeroes = &raw_co_pwrite_zeroes,
.bdrv_co_pdiscard = &raw_co_pdiscard,
.bdrv_co_block_status = &raw_co_block_status,
.bdrv_co_copy_range_from = &raw_co_copy_range_from,
.bdrv_co_copy_range_to = &raw_co_copy_range_to,
.bdrv_co_truncate = &raw_co_truncate,
.bdrv_getlength = &raw_getlength,
.has_variable_length = true,
.bdrv_measure = &raw_measure,
.bdrv_get_info = &raw_get_info,
.bdrv_refresh_limits = &raw_refresh_limits,
.bdrv_probe_blocksizes = &raw_probe_blocksizes,
.bdrv_probe_geometry = &raw_probe_geometry,
.bdrv_eject = &raw_eject,
.bdrv_lock_medium = &raw_lock_medium,
.bdrv_co_ioctl = &raw_co_ioctl,
.create_opts = &raw_create_opts,
.bdrv_has_zero_init = &raw_has_zero_init,
.bdrv_has_zero_init_truncate = &raw_has_zero_init_truncate,
.strong_runtime_opts = raw_strong_runtime_opts,
.mutable_opts = mutable_opts,
};
static void bdrv_raw_init(void)
{
bdrv_register(&bdrv_raw);
}
block_init(bdrv_raw_init);