In current implementation virtio-blk assumes that request will be completed by the underlying transport. This assumption has lead to problems when virtio-blk driver is used on the real H/W where device couldn't complete the request and driver ended up waiting for it forever in the production. This implements a straightforward block layer request timeout handler. It completes the timed-out request in the same context if the virtio device has a VIRTIO_CONFIG_S_DRIVER_OK status. For any other status indicated by the virtio device, we halt the block layer request queue and proceed with the tear-down sequence. This ensures that applications waiting for the I/O can exit gracefully, preventing problematic devices from receiving additional I/O and potentially causing more issues. Without this patch when a request gets timed out on virtio-blk device it leaves the application hanging avoiding graceful termination & cleanup. Timeout handlers can be implemented differently and we can apply different teardown policies, I'm open if anyone has better suggestion for teardown hence marking it as RFC. * Below is the test output on today's linux-block tree [1] with patch and test script to trigger simple timeout and trigger teardown sequence that follows following sequence :- - Load virtio-blk module with io_timeout=10 and timeout teardown limit=2. - Run fio randwrite with multiple jobs (48=NCPUS). - Enable fault injection request timeout. - While fio is running it will trigger request timeout handler because of fault injection. - First two timed out requests will be completed with the time out error without initiating teardown. - For third request it will initiate the teardown by issuing teardown work, that will perform device teardown sequence. - Make sure all the fio jobs terminate gracefully and fio will run for the time we set the timeout value i.e. 10s. - Lastly remove vitio-blk kernel module to make sure we are not holding any reference or pending resources post teardown. Any feedback is welcome. -ck [1] commit 20d713ea3192ca6735d669ce583a7d2183bd2f81 (origin/for-next) Merge: 2cc14f52aeb7 668bfeeabb5e Author: Jens Axboe <axboe@xxxxxxxxx> Date: Mon Nov 27 09:11:54 2023 -0700 Merge branch 'for-6.8/block' into for-next * for-6.8/block: block: move a few definitions out of CONFIG_BLK_DEV_ZONED block/rnbd: use %pe to print errors block/rnbd: add support for REQ_OP_WRITE_ZEROES Chaitanya Kulkarni (1): virtio-blk: process block layer timedout request drivers/block/virtio_blk.c | 122 ++++++++++++++++++++++++++++++++ include/uapi/linux/virtio_blk.h | 1 + 2 files changed, 123 insertions(+) * Test script test-virtio-timeout.sh :- ---------------------------------------------------------------------------- setup() { echo "[RANDWRITE]" > /tmp/randwrite.fio echo "direct=1" >> /tmp/randwrite.fio echo "rw=randwrite" >> /tmp/randwrite.fio echo "norandommap" >> /tmp/randwrite.fio echo "randrepeat=0" >> /tmp/randwrite.fio echo "runtime=1m" >> /tmp/randwrite.fio echo "time_based" >> /tmp/randwrite.fio echo "iodepth=2" >> /tmp/randwrite.fio echo "numjobs=48" >> /tmp/randwrite.fio echo "bs=4k" >> /tmp/randwrite.fio echo "overwrite=0" >> /tmp/randwrite.fio echo "allow_file_create=0" >> /tmp/randwrite.fio echo "group_reporting" >> /tmp/randwrite.fio echo "" >> /tmp/randwrite.fio ./compile_virtioblk.sh modprobe -r virtio_blk echo "--------------------------------------------" echo "Loading virtio-blk module with io_timeout=30 timeout_teardown_limit=2" modprobe virtio_blk io_timeout=30 timeout_teardown_limit=2 echo "--------------------------------------------" sleep 1 set -x lsblk ls -lrth /dev/vda cat /sys/block/vda/io-timeout-fail echo 1 > /sys/block/vda/io-timeout-fail cat /sys/block/vda/io-timeout-fail echo 20 > /sys/kernel/debug/fail_io_timeout/probability echo 10 > /sys/kernel/debug/fail_io_timeout/interval echo -1 > /sys/kernel/debug/fail_io_timeout/times echo 0 > /sys/kernel/debug/fail_io_timeout/space echo 1 > /sys/kernel/debug/fail_io_timeout/verbose set +x dmesg -c } teardown() { modprobe -r virtio_blk } main() { setup set -x fio /tmp/randwrite.fio --filename=/dev/vda --ioengine=libaio set +x echo "--------------------------------------------" echo "device should be gone from lablk" set -x ls -lrth /dev/vda lsblk teardown } main * Test result :- ---------------------------------------------------------------------------- linux-block (for-next) # git am p/virtio-blk-timeout/0001-virtio-blk-process-block-layer-timedout-request.patch Applying: virtio-blk: process block layer timedout request linux-block (for-next) # git log -1 commit 8f4403d78557ea6393948f8d427be0dc98e4e8c1 (HEAD -> for-next) Author: Chaitanya Kulkarni <kch@xxxxxxxxxx> Date: Mon Oct 9 17:48:50 2023 -0700 virtio-blk: process block layer timedout request Improve block layer request handling by implementing a timeout handler. Current implementation assums that request will never timeout and will be completed by underlaying transport. However, this assumption can cause issues under heavy load especially when dealing with different subsystems and real hardware. To solve this, add a block layer request timeout handler that will complete timed-out requests in the same context if the virtio device has a VIRTIO_CONFIG_S_DRIVER_OK status. If the device has any other status, we'll stop the block layer request queue and proceed with the teardown sequence, allowing applications waiting for I/O to exit gracefully with appropriate error. Also, add two new module parameters that allows user to specify the I/O timeout for the tagset when allocating the disk and a teardown limit for the timed out requeets before we initiate device teardown from the timeout handler. These changes will improve the stability and reliability of our system under request timeout scenario. Signed-off-by: Chaitanya Kulkarni <kch@xxxxxxxxxx> linux-block (for-next) # ./compile_virtioblk.sh + dmesg -c + modprobe -r virtio_blk + lsmod + grep virtio_blk ++ nproc + make -j 48 M=drivers/block modules CC [M] drivers/block/virtio_blk.o MODPOST drivers/block/Module.symvers LD [M] drivers/block/virtio_blk.ko + HOST=drivers/block/ ++ uname -r + HOST_DEST=/lib/modules/6.7.0-rc3lblk+/kernel/drivers/block/ + cp drivers/block//virtio_blk.ko /lib/modules/6.7.0-rc3lblk+/kernel/drivers/block// + ls -lrth /lib/modules/6.7.0-rc3lblk+/kernel/drivers/block//virtio_blk.ko -rw-r--r--. 1 root root 641K Nov 29 15:19 /lib/modules/6.7.0-rc3lblk+/kernel/drivers/block//virtio_blk.ko linux-block (for-next) # ./test-virtio-timeout.sh + dmesg -c + modprobe -r virtio_blk + lsmod + grep virtio_blk ++ nproc + make -j 48 M=drivers/block modules + HOST=drivers/block/ ++ uname -r + HOST_DEST=/lib/modules/6.7.0-rc3lblk+/kernel/drivers/block/ + cp drivers/block//virtio_blk.ko /lib/modules/6.7.0-rc3lblk+/kernel/drivers/block// + ls -lrth /lib/modules/6.7.0-rc3lblk+/kernel/drivers/block//virtio_blk.ko -rw-r--r--. 1 root root 641K Nov 29 15:20 /lib/modules/6.7.0-rc3lblk+/kernel/drivers/block//virtio_blk.ko -------------------------------------------- Loading virtio-blk module with io_timeout=10 timeout_teardown_limit=2 ++ modprobe virtio_blk io_timeout=40 timeout_teardown_limit=2 ++ set +x -------------------------------------------- ++ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 49G 0 part /home sdb 8:16 0 100G 0 disk /mnt/data sr0 11:0 1 1024M 0 rom vda 252:0 0 5G 0 disk nvme0n1 259:0 0 1G 0 disk ++ ls -lrth /dev/vda brw-rw----. 1 root disk 252, 0 Nov 29 15:20 /dev/vda ++ cat /sys/block/vda/io-timeout-fail 0 ++ echo 1 ++ cat /sys/block/vda/io-timeout-fail 1 ++ echo 20 ++ echo 10 ++ echo -1 ++ echo 0 ++ echo 1 ++ set +x [ 464.285445] virtio_blk virtio1: 48/0/0 default/read/poll queues [ 464.293352] virtio_blk virtio1: [vda] 10485760 512-byte logical blocks (5.37 GB/5.00 GiB) ++ fio /tmp/randwrite.fio --filename=/dev/vda --ioengine=libaio RANDWRITE: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=2 ... fio-3.34 Starting 48 processes fio: io_u error on file /dev/vda: Connection timed out: write offset=2181410816, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4479356928, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=313679872, buflen=4096 fio: pid=4045, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=4772716544, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=105332736, buflen=4096 fio: pid=4000, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2928922624, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4838883328, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4589166592, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=5146509312, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2520354816, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3324887040, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3058372608, buflen=4096 fio: pid=4001, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4034, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=3189833728, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2009739264, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1963376640, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4359561216, buflen=4096 fio: pid=4005, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=298274816, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1827557376, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=402067456, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=5360013312, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1807507456, buflen=4096 fio: pid=4044, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=3999, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4042, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=3963465728, buflen=4096 fio: pid=4002, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2294935552, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4134977536, buflen=4096 fio: pid=4007, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=5277339648, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=169168896, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3403808768, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2951380992, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2899501056, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4529233920, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1837285376, buflen=4096 fio: pid=4003, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4012, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4009, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4010, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4008, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=4564606976, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=212725760, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1962016768, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1700605952, buflen=4096 fio: pid=4017, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4013, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=4589961216, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1288470528, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1131532288, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3486863360, buflen=4096 fio: pid=4023, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=3674542080, buflen=4096 fio: pid=4014, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2965827584, buflen=4096 fio: pid=4015, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=4076720128, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3765477376, buflen=4096 fio: pid=4016, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2116341760, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=119099392, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2960650240, buflen=4096 fio: pid=4018, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=3803418624, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1891971072, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=63213568, buflen=4096 fio: pid=4019, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=1702731776, buflen=4096 fio: pid=4020, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=1342504960, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1720606720, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2498568192, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2751967232, buflen=4096 fio: pid=4021, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=150994944, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2458804224, buflen=4096 fio: pid=4022, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4024, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=5106069504, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3151101952, buflen=4096 fio: pid=4025, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2127577088, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3512651776, buflen=4096 fio: pid=4026, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=4321529856, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1877729280, buflen=4096 fio: pid=4027, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2883231744, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1158828032, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=2076794880, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4819566592, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1326583808, buflen=4096 fio: pid=4038, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4006, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2812641280, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3819180032, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=307916800, buflen=4096 fio: pid=4011, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=3831308288, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1140715520, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4298055680, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=398614528, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1207713792, buflen=4096 fio: pid=4030, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4028, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4043, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2714513408, buflen=4096 fio: pid=3998, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=4391649280, buflen=4096 fio: pid=4031, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=103710720, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=121716736, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3203006464, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=635932672, buflen=4096 fio: pid=4032, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4040, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=2235961344, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3987615744, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3183620096, buflen=4096 fio: pid=4041, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=706084864, buflen=4096 fio: pid=4035, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=732864512, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3141156864, buflen=4096 fio: pid=4036, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=1853272064, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3174068224, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=4283023360, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=1962606592, buflen=4096 fio: pid=4039, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=180465664, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3477286912, buflen=4096 fio: pid=4037, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: pid=4033, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=4288196608, buflen=4096 fio: io_u error on file /dev/vda: Connection timed out: write offset=3106217984, buflen=4096 fio: pid=4029, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out fio: io_u error on file /dev/vda: Connection timed out: write offset=3785584640, buflen=4096 fio: pid=4004, err=110/file:io_u.c:1889, func=io_u error, error=Connection timed out RANDWRITE: (groupid=0, jobs=48): err=110 (file:io_u.c:1889, func=io_u error, error=Connection timed out): pid=3998: Wed Nov 29 15:20:50 2023 write: IOPS=111, BW=438KiB/s (449kB/s)(18.8MiB/43930msec); 0 zone resets slat (nsec): min=2585, max=85232, avg=11030.13, stdev=6110.05 clat (usec): min=24, max=1759, avg=437.53, stdev=332.56 lat (usec): min=29, max=1776, avg=448.56, stdev=333.61 clat percentiles (usec): | 1.00th=[ 38], 5.00th=[ 46], 10.00th=[ 61], 20.00th=[ 139], | 30.00th=[ 196], 40.00th=[ 326], 50.00th=[ 412], 60.00th=[ 453], | 70.00th=[ 537], 80.00th=[ 676], 90.00th=[ 906], 95.00th=[ 1020], | 99.00th=[ 1565], 99.50th=[ 1680], 99.90th=[ 1713], 99.95th=[ 1729], | 99.99th=[ 1762] bw ( KiB/s): min=38539, max=38539, per=100.00%, avg=38539.00, stdev= 0.00, samples=48 iops : min= 9627, max= 9627, avg=9627.00, stdev= 0.00, samples=48 lat (usec) : 50=6.44%, 100=7.46%, 250=21.25%, 500=29.12%, 750=19.62% lat (usec) : 1000=8.70% lat (msec) : 2=5.46% cpu : usr=0.00%, sys=0.01%, ctx=4094, majf=0, minf=1004 IO depths : 1=1.0%, 2=99.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, >=64=0.0% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=0.1%, 4=99.9%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% issued rwts: total=0,4908,0,0 short=0,0,0,0 dropped=0,0,0,0 latency : target=0, window=0, percentile=100.00%, depth=2 Run status group 0 (all jobs): WRITE: bw=438KiB/s (449kB/s), 438KiB/s-438KiB/s (449kB/s-449kB/s), io=18.8MiB (19.7MB), run=43930-43930msec Disk stats (read/write): vda: ios=7/4812, merge=0/0, ticks=1/2030, in_queue=2031, util=99.76% ++ set +x -------------------------------------------- device should be gone from lablk ++ ls -lrth /dev/vda ls: cannot access '/dev/vda': No such file or directory ++ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 50G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 49G 0 part /home sdb 8:16 0 100G 0 disk /mnt/data sr0 11:0 1 1024M 0 rom nvme0n1 259:0 0 1G 0 disk ++ teardown ++ modprobe -r virtio_blk linux-block (for-next) # lsmod | grep virtio_blk -- 2.40.0