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/*
* QEMU block throttling filter driver infrastructure
*
* Copyright (c) 2017 Manos Pitsidianakis
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 or
* (at your option) version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "block/throttle-groups.h"
#include "qemu/throttle-options.h"
#include "qapi/error.h"
static QemuOptsList throttle_opts = {
.name = "throttle",
.head = QTAILQ_HEAD_INITIALIZER(throttle_opts.head),
.desc = {
{
.name = QEMU_OPT_THROTTLE_GROUP_NAME,
.type = QEMU_OPT_STRING,
.help = "Name of the throttle group",
},
{ /* end of list */ }
},
};
static int throttle_configure_tgm(BlockDriverState *bs,
ThrottleGroupMember *tgm,
QDict *options, Error **errp)
{
int ret;
const char *group_name;
Error *local_err = NULL;
QemuOpts *opts = qemu_opts_create(&throttle_opts, NULL, 0, &error_abort);
qemu_opts_absorb_qdict(opts, options, &local_err);
if (local_err) {
error_propagate(errp, local_err);
ret = -EINVAL;
goto fin;
}
group_name = qemu_opt_get(opts, QEMU_OPT_THROTTLE_GROUP_NAME);
if (!group_name) {
error_setg(errp, "Please specify a throttle group");
ret = -EINVAL;
goto fin;
} else if (!throttle_group_exists(group_name)) {
error_setg(errp, "Throttle group '%s' does not exist", group_name);
ret = -EINVAL;
goto fin;
}
/* Register membership to group with name group_name */
throttle_group_register_tgm(tgm, group_name, bdrv_get_aio_context(bs));
ret = 0;
fin:
qemu_opts_del(opts);
return ret;
}
static int throttle_open(BlockDriverState *bs, QDict *options,
int flags, Error **errp)
{
ThrottleGroupMember *tgm = bs->opaque;
bs->file = bdrv_open_child(NULL, options, "file", bs,
&child_file, false, errp);
if (!bs->file) {
return -EINVAL;
}
bs->supported_write_flags = bs->file->bs->supported_write_flags;
bs->supported_zero_flags = bs->file->bs->supported_zero_flags;
return throttle_configure_tgm(bs, tgm, options, errp);
}
static void throttle_close(BlockDriverState *bs)
{
ThrottleGroupMember *tgm = bs->opaque;
throttle_group_unregister_tgm(tgm);
}
static int64_t throttle_getlength(BlockDriverState *bs)
{
return bdrv_getlength(bs->file->bs);
}
static int coroutine_fn throttle_co_preadv(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
ThrottleGroupMember *tgm = bs->opaque;
throttle_group_co_io_limits_intercept(tgm, bytes, false);
return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
}
static int coroutine_fn throttle_co_pwritev(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov, int flags)
{
ThrottleGroupMember *tgm = bs->opaque;
throttle_group_co_io_limits_intercept(tgm, bytes, true);
return bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);
}
static int coroutine_fn throttle_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int bytes,
BdrvRequestFlags flags)
{
ThrottleGroupMember *tgm = bs->opaque;
throttle_group_co_io_limits_intercept(tgm, bytes, true);
return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
}
static int coroutine_fn throttle_co_pdiscard(BlockDriverState *bs,
int64_t offset, int bytes)
{
ThrottleGroupMember *tgm = bs->opaque;
throttle_group_co_io_limits_intercept(tgm, bytes, true);
return bdrv_co_pdiscard(bs->file->bs, offset, bytes);
}
static int throttle_co_flush(BlockDriverState *bs)
{
return bdrv_co_flush(bs->file->bs);
}
static void throttle_detach_aio_context(BlockDriverState *bs)
{
ThrottleGroupMember *tgm = bs->opaque;
throttle_group_detach_aio_context(tgm);
}
static void throttle_attach_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
ThrottleGroupMember *tgm = bs->opaque;
throttle_group_attach_aio_context(tgm, new_context);
}
static int throttle_reopen_prepare(BDRVReopenState *reopen_state,
BlockReopenQueue *queue, Error **errp)
{
ThrottleGroupMember *tgm;
assert(reopen_state != NULL);
assert(reopen_state->bs != NULL);
reopen_state->opaque = g_new0(ThrottleGroupMember, 1);
tgm = reopen_state->opaque;
return throttle_configure_tgm(reopen_state->bs, tgm, reopen_state->options,
errp);
}
static void throttle_reopen_commit(BDRVReopenState *reopen_state)
{
ThrottleGroupMember *old_tgm = reopen_state->bs->opaque;
ThrottleGroupMember *new_tgm = reopen_state->opaque;
throttle_group_unregister_tgm(old_tgm);
g_free(old_tgm);
reopen_state->bs->opaque = new_tgm;
reopen_state->opaque = NULL;
}
static void throttle_reopen_abort(BDRVReopenState *reopen_state)
{
ThrottleGroupMember *tgm = reopen_state->opaque;
throttle_group_unregister_tgm(tgm);
g_free(tgm);
reopen_state->opaque = NULL;
}
static bool throttle_recurse_is_first_non_filter(BlockDriverState *bs,
BlockDriverState *candidate)
{
return bdrv_recurse_is_first_non_filter(bs->file->bs, candidate);
}
static BlockDriver bdrv_throttle = {
.format_name = "throttle",
.protocol_name = "throttle",
.instance_size = sizeof(ThrottleGroupMember),
.bdrv_file_open = throttle_open,
.bdrv_close = throttle_close,
.bdrv_co_flush = throttle_co_flush,
.bdrv_child_perm = bdrv_filter_default_perms,
.bdrv_getlength = throttle_getlength,
.bdrv_co_preadv = throttle_co_preadv,
.bdrv_co_pwritev = throttle_co_pwritev,
.bdrv_co_pwrite_zeroes = throttle_co_pwrite_zeroes,
.bdrv_co_pdiscard = throttle_co_pdiscard,
.bdrv_recurse_is_first_non_filter = throttle_recurse_is_first_non_filter,
.bdrv_attach_aio_context = throttle_attach_aio_context,
.bdrv_detach_aio_context = throttle_detach_aio_context,
.bdrv_reopen_prepare = throttle_reopen_prepare,
.bdrv_reopen_commit = throttle_reopen_commit,
.bdrv_reopen_abort = throttle_reopen_abort,
.bdrv_co_get_block_status = bdrv_co_get_block_status_from_file,
.is_filter = true,
};
static void bdrv_throttle_init(void)
{
bdrv_register(&bdrv_throttle);
}
block_init(bdrv_throttle_init);
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