On Mon, Apr 14, 2025 at 07:25:50PM +0800, Ming Lei wrote:
> From: Uday Shankar <ushankar@xxxxxxxxxxxxxxx>
>
> Add one simple fault inject target, and verify if it can be exited in
> expected period.
What "it" refers to is unclear. Maybe say "verify if an application
using ublk device sees an I/O error quickly after the ublk server dies?"
>
> Signed-off-by: Uday Shankar <ushankar@xxxxxxxxxxxxxxx>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> ---
> tools/testing/selftests/ublk/Makefile | 4 +-
> tools/testing/selftests/ublk/fault_inject.c | 98 +++++++++++++++++++
> tools/testing/selftests/ublk/kublk.c | 3 +-
> tools/testing/selftests/ublk/kublk.h | 12 ++-
> .../testing/selftests/ublk/test_generic_06.sh | 41 ++++++++
> 5 files changed, 155 insertions(+), 3 deletions(-)
> create mode 100644 tools/testing/selftests/ublk/fault_inject.c
> create mode 100755 tools/testing/selftests/ublk/test_generic_06.sh
>
> diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
> index dddc64036aa1..ec4624a283bc 100644
> --- a/tools/testing/selftests/ublk/Makefile
> +++ b/tools/testing/selftests/ublk/Makefile
> @@ -8,6 +8,7 @@ TEST_PROGS += test_generic_02.sh
> TEST_PROGS += test_generic_03.sh
> TEST_PROGS += test_generic_04.sh
> TEST_PROGS += test_generic_05.sh
> +TEST_PROGS += test_generic_06.sh
>
> TEST_PROGS += test_null_01.sh
> TEST_PROGS += test_null_02.sh
> @@ -31,7 +32,8 @@ TEST_GEN_PROGS_EXTENDED = kublk
>
> include ../lib.mk
>
> -$(TEST_GEN_PROGS_EXTENDED): kublk.c null.c file_backed.c common.c stripe.c
> +$(TEST_GEN_PROGS_EXTENDED): kublk.c null.c file_backed.c common.c stripe.c \
> + fault_inject.c
>
> check:
> shellcheck -x -f gcc *.sh
> diff --git a/tools/testing/selftests/ublk/fault_inject.c b/tools/testing/selftests/ublk/fault_inject.c
> new file mode 100644
> index 000000000000..94a8e729ba4c
> --- /dev/null
> +++ b/tools/testing/selftests/ublk/fault_inject.c
> @@ -0,0 +1,98 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Fault injection ublk target. Hack this up however you like for
> + * testing specific behaviors of ublk_drv. Currently is a null target
> + * with a configurable delay before completing each I/O. This delay can
> + * be used to test ublk_drv's handling of I/O outstanding to the ublk
> + * server when it dies.
> + */
> +
> +#include "kublk.h"
> +
> +static int ublk_fault_inject_tgt_init(const struct dev_ctx *ctx,
> + struct ublk_dev *dev)
> +{
> + const struct ublksrv_ctrl_dev_info *info = &dev->dev_info;
> + unsigned long dev_size = 250UL << 30;
> +
> + dev->tgt.dev_size = dev_size;
> + dev->tgt.params = (struct ublk_params) {
> + .types = UBLK_PARAM_TYPE_BASIC,
> + .basic = {
> + .logical_bs_shift = 9,
> + .physical_bs_shift = 12,
> + .io_opt_shift = 12,
> + .io_min_shift = 9,
> + .max_sectors = info->max_io_buf_bytes >> 9,
> + .dev_sectors = dev_size >> 9,
> + },
> + };
> +
> + dev->private_data = (void *)(unsigned long)(ctx->fault_inject.delay_us * 1000);
> + return 0;
> +}
> +
> +static int ublk_fault_inject_queue_io(struct ublk_queue *q, int tag)
> +{
> + const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
> + struct io_uring_sqe *sqe;
> + struct __kernel_timespec ts = {
> + .tv_nsec = (long long)q->dev->private_data,
> + };
> +
> + ublk_queue_alloc_sqes(q, &sqe, 1);
> + io_uring_prep_timeout(sqe, &ts, 1, 0);
> + sqe->user_data = build_user_data(tag, ublksrv_get_op(iod), 0, 1);
> +
> + ublk_queued_tgt_io(q, tag, 1);
> +
> + return 0;
> +}
> +
> +static void ublk_fault_inject_tgt_io_done(struct ublk_queue *q, int tag,
> + const struct io_uring_cqe *cqe)
> +{
> + const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
> +
> + if (cqe->res != -ETIME)
> + ublk_err("%s: unexpected cqe res %d\n", __func__, cqe->res);
> +
> + if (ublk_completed_tgt_io(q, tag))
> + ublk_complete_io(q, tag, iod->nr_sectors << 9);
> + else
> + ublk_err("%s: io not complete after 1 cqe\n", __func__);
> +}
> +
> +static void ublk_fault_inject_cmd_line(struct dev_ctx *ctx, int argc, char *argv[])
> +{
> + static const struct option longopts[] = {
> + { "delay_us", 1, NULL, 0 },
> + { 0, 0, 0, 0 }
> + };
> + int option_idx, opt;
> +
> + ctx->fault_inject.delay_us = 0;
> + while ((opt = getopt_long(argc, argv, "",
> + longopts, &option_idx)) != -1) {
> + switch (opt) {
> + case 0:
> + if (!strcmp(longopts[option_idx].name, "delay_us"))
> + ctx->fault_inject.delay_us = strtoll(optarg, NULL, 10);
> + }
> + }
> +}
> +
> +static void ublk_fault_inject_usage(const struct ublk_tgt_ops *ops)
> +{
> + printf("\tfault_inject: [--delay_us us (default 0)]\n");
> +}
> +
> +const struct ublk_tgt_ops fault_inject_tgt_ops = {
> + .name = "fault_inject",
> + .init_tgt = ublk_fault_inject_tgt_init,
> + .queue_io = ublk_fault_inject_queue_io,
> + .tgt_io_done = ublk_fault_inject_tgt_io_done,
> + .parse_cmd_line = ublk_fault_inject_cmd_line,
> + .usage = ublk_fault_inject_usage,
> +};
> diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c
> index 0cd6dce3f303..759f06637146 100644
> --- a/tools/testing/selftests/ublk/kublk.c
> +++ b/tools/testing/selftests/ublk/kublk.c
> @@ -12,6 +12,7 @@ static const struct ublk_tgt_ops *tgt_ops_list[] = {
> &null_tgt_ops,
> &loop_tgt_ops,
> &stripe_tgt_ops,
> + &fault_inject_tgt_ops,
> };
>
> static const struct ublk_tgt_ops *ublk_find_tgt(const char *name)
> @@ -1234,7 +1235,7 @@ static void __cmd_create_help(char *exe, bool recovery)
> {
> int i;
>
> - printf("%s %s -t [null|loop|stripe] [-q nr_queues] [-d depth] [-n dev_id]\n",
> + printf("%s %s -t [null|loop|stripe|fault_inject] [-q nr_queues] [-d depth] [-n dev_id]\n",
> exe, recovery ? "recover" : "add");
> printf("\t[--foreground] [--quiet] [-z] [--debug_mask mask] [-r 0|1 ] [-g 0|1]\n");
> printf("\t[-e 0|1 ] [-i 0|1]\n");
> diff --git a/tools/testing/selftests/ublk/kublk.h b/tools/testing/selftests/ublk/kublk.h
> index 3d2b9f14491c..29571eb296f1 100644
> --- a/tools/testing/selftests/ublk/kublk.h
> +++ b/tools/testing/selftests/ublk/kublk.h
> @@ -68,6 +68,11 @@ struct stripe_ctx {
> unsigned int chunk_size;
> };
>
> +struct fault_inject_ctx {
> + /* fault_inject */
> + unsigned long delay_us;
> +};
> +
> struct dev_ctx {
> char tgt_type[16];
> unsigned long flags;
> @@ -81,6 +86,9 @@ struct dev_ctx {
> unsigned int fg:1;
> unsigned int recovery:1;
>
> + /* fault_inject */
> + long long delay_us;
> +
> int _evtfd;
> int _shmid;
>
> @@ -88,7 +96,8 @@ struct dev_ctx {
> struct ublk_dev *shadow_dev;
>
> union {
> - struct stripe_ctx stripe;
> + struct stripe_ctx stripe;
> + struct fault_inject_ctx fault_inject;
> };
> };
>
> @@ -384,6 +393,7 @@ static inline int ublk_queue_use_zc(const struct ublk_queue *q)
> extern const struct ublk_tgt_ops null_tgt_ops;
> extern const struct ublk_tgt_ops loop_tgt_ops;
> extern const struct ublk_tgt_ops stripe_tgt_ops;
> +extern const struct ublk_tgt_ops fault_inject_tgt_ops;
>
> void backing_file_tgt_deinit(struct ublk_dev *dev);
> int backing_file_tgt_init(struct ublk_dev *dev);
> diff --git a/tools/testing/selftests/ublk/test_generic_06.sh b/tools/testing/selftests/ublk/test_generic_06.sh
> new file mode 100755
> index 000000000000..b67230c42c84
> --- /dev/null
> +++ b/tools/testing/selftests/ublk/test_generic_06.sh
> @@ -0,0 +1,41 @@
> +#!/bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +
> +. "$(cd "$(dirname "$0")" && pwd)"/test_common.sh
> +
> +TID="generic_06"
> +ERR_CODE=0
> +
> +_prep_test "fault_inject" "fast cleanup when all I/Os of one hctx are in server"
> +
> +# configure ublk server to sleep 2s before completing each I/O
> +dev_id=$(_add_ublk_dev -t fault_inject -q 2 -d 1 --delay_us 2000000)
> +_check_add_dev $TID $?
> +
> +STARTTIME=${SECONDS}
> +
> +dd if=/dev/urandom of=/dev/ublkb${dev_id} oflag=direct bs=4k count=1 status=none > /dev/null 2>&1 &
> +dd_pid=$!
> +
> +__ublk_kill_daemon ${dev_id} "DEAD"
> +
> +wait $dd_pid
> +dd_exitcode=$?
> +
> +ENDTIME=${SECONDS}
> +ELAPSED=$(($ENDTIME - $STARTTIME))
> +
> +# assert that dd sees an error and exits quickly after ublk server is
> +# killed. previously this relied on seeing an I/O timeout and so would
> +# take ~30s
> +if [ $dd_exitcode -eq 0 ]; then
> + echo "dd unexpectedly exited successfully!"
> + ERR_CODE=255
> +fi
> +if [ $ELAPSED -ge 5 ]; then
> + echo "dd took $ELAPSED seconds to exit (>= 5s tolerance)!"
> + ERR_CODE=255
> +fi
> +
> +_cleanup_test "fault_inject"
> +_show_result $TID $ERR_CODE
> --
> 2.47.0
>
