blkdebug: Add 'delay-ns' option

Sometimes reproducing a problem for debugging involves slow I/O, so
let's add something to blkdebug to make I/O slow when we need it. This
can be used either together with an error so that the request fails
after the delay, or with errno=0, which allows the request to succeed
after the delay.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20260421161132.99878-2-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf
2026-04-21 18:11:26 +02:00
parent 6d17fd91f6
commit d5e4090177
2 changed files with 18 additions and 1 deletions

View File

@@ -95,6 +95,7 @@ typedef struct BlkdebugRule {
int immediately;
int once;
int64_t offset;
int64_t delay_ns;
} inject;
struct {
int new_state;
@@ -144,6 +145,10 @@ static QemuOptsList inject_error_opts = {
.name = "immediately",
.type = QEMU_OPT_BOOL,
},
{
.name = "delay-ns",
.type = QEMU_OPT_NUMBER,
},
{ /* end of list */ }
},
};
@@ -216,6 +221,8 @@ static int add_rule(void *opaque, QemuOpts *opts, Error **errp)
rule->options.inject.once = qemu_opt_get_bool(opts, "once", 0);
rule->options.inject.immediately =
qemu_opt_get_bool(opts, "immediately", 0);
rule->options.inject.delay_ns =
qemu_opt_get_number(opts, "delay-ns", 0);
sector = qemu_opt_get_number(opts, "sector", -1);
rule->options.inject.offset =
sector == -1 ? -1 : sector * BDRV_SECTOR_SIZE;
@@ -594,6 +601,7 @@ static int coroutine_fn rule_check(BlockDriverState *bs, uint64_t offset,
BlkdebugRule *rule;
int error;
bool immediately;
int64_t delay_ns;
qemu_mutex_lock(&s->lock);
QSIMPLEQ_FOREACH(rule, &s->active_rules, active_next) {
@@ -608,13 +616,14 @@ static int coroutine_fn rule_check(BlockDriverState *bs, uint64_t offset,
}
}
if (!rule || !rule->options.inject.error) {
if (!rule) {
qemu_mutex_unlock(&s->lock);
return 0;
}
immediately = rule->options.inject.immediately;
error = rule->options.inject.error;
delay_ns = rule->options.inject.delay_ns;
if (rule->options.inject.once) {
QSIMPLEQ_REMOVE(&s->active_rules, rule, BlkdebugRule, active_next);
@@ -622,6 +631,10 @@ static int coroutine_fn rule_check(BlockDriverState *bs, uint64_t offset,
}
qemu_mutex_unlock(&s->lock);
if (delay_ns) {
qemu_co_sleep_ns(QEMU_CLOCK_REALTIME, delay_ns);
}
if (!immediately) {
aio_co_schedule(qemu_get_current_aio_context(), qemu_coroutine_self());
qemu_coroutine_yield();

View File

@@ -3919,6 +3919,9 @@
#
# @errno: error identifier (errno) to be returned; defaults to EIO
#
# @delay-ns: request delay before completion in nanoseconds
# (default: 0, since: 11.1)
#
# @sector: specifies the sector index which has to be affected in
# order to actually trigger the event; defaults to "any sector"
#
@@ -3934,6 +3937,7 @@
'*state': 'int',
'*iotype': 'BlkdebugIOType',
'*errno': 'int',
'*delay-ns': 'int',
'*sector': 'int',
'*once': 'bool',
'*immediately': 'bool' } }