# Test to underatand following cases:

1. io-timeout=30
2. io-timeout=300
3. io-timeout=330
4. io-timeout=0

**On Terminal 1:**

$ rbd-nbd map rbd-pool/image0 --try-netlink --reattach-timeout 300 --io-timeout $CASE_SPECIFIC
$ mkfs.ext4 /dev/nbd0
$ mount /dev/nbd0 /mnt/
$ dd if=/dev/urandom of=/mnt/file bs=1k

**On Terminal 2:**

$ pkill -SIGTERM rbd-nbd

**Note:**
1. In all the cases reattach-timeout is 300 fixed.
2. Kernel Version: Linux linux-vm1 5.14.0-rc3+ #3 SMP Fri Aug 6 12:13:44 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

### CASE 1:
#### What happens with 30 sec io-timeout
##### i.e reattach-timeout > io-timeout

[Aug12 06:50] nbd0: detected capacity change from 0 to 2097152
[Aug12 06:51] EXT4-fs (nbd0): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[Aug12 06:52] block nbd0: Receive control failed (result -32)
[  +0.004259] block nbd0: Dead connection, failed to find a fallback
[Aug12 06:57] block nbd0: shutting down sockets
[  +0.000143] blk_update_request: I/O error, dev nbd0, sector 2097024 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[  +0.000080] blk_update_request: I/O error, dev nbd0, sector 1032 op 0x0:(READ) flags 0x3000 phys_seg 1 prio class 0
[  +0.000185] EXT4-fs error (device nbd0): ext4_wait_block_bitmap:531: comm kworker/u24:3: Cannot read block bitmap - block_group = 0, block_bitmap = 129
[  +0.001080] blk_update_request: I/O error, dev nbd0, sector 278528 op 0x1:(WRITE) flags 0x4000 phys_seg 17 prio class 0
[  +0.000250] blk_update_request: I/O error, dev nbd0, sector 278784 op 0x1:(WRITE) flags 0x4000 phys_seg 17 prio class 0
[  +0.000228] blk_update_request: I/O error, dev nbd0, sector 279040 op 0x1:(WRITE) flags 0x4000 phys_seg 15 prio class 0
[  +0.000194] blk_update_request: I/O error, dev nbd0, sector 279296 op 0x1:(WRITE) flags 0x4000 phys_seg 17 prio class 0
[  +0.000131] blk_update_request: I/O error, dev nbd0, sector 279552 op 0x1:(WRITE) flags 0x4000 phys_seg 17 prio class 0
[  +0.000103] blk_update_request: I/O error, dev nbd0, sector 279808 op 0x1:(WRITE) flags 0x4000 phys_seg 10 prio class 0
[  +0.000130] blk_update_request: I/O error, dev nbd0, sector 280064 op 0x1:(WRITE) flags 0x4000 phys_seg 9 prio class 0
[  +0.000224] blk_update_request: I/O error, dev nbd0, sector 280320 op 0x1:(WRITE) flags 0x4000 phys_seg 17 prio class 0
[  +0.000774] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 35244)
[  +0.001435] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 35648)
[  +0.000551] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 36631)
[  +0.000254] Aborting journal on device nbd0-8.
[  +0.000103] Buffer I/O error on dev nbd0, logical block 131072, lost sync page write
[  +0.000123] JBD2: Error -5 detected when updating journal superblock for nbd0-8.
[  +0.000274] EXT4-fs error (device nbd0): ext4_check_bdev_write_error:215: comm kworker/u24:3: Error while async write back metadata
[  +0.000063] EXT4-fs (nbd0): Delayed block allocation failed for inode 12 at logical offset 2048 with max blocks 2048 with error 30
[  +0.000047] EXT4-fs (nbd0): This should not happen!! Data will be lost

[  +0.000051] EXT4-fs error (device nbd0) in ext4_writepages:2813: Journal has aborted
[  +0.002436] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 36864)
[  +0.000063] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm dd: Detected aborted journal
[  +0.000074] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm kworker/u24:2: Detected aborted journal
[  +0.000090] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000093] EXT4-fs (nbd0): previous I/O error to superblock detected
[  +0.000002] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000003] EXT4-fs (nbd0): Remounting filesystem read-only
[  +0.000072] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000091] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000043] EXT4-fs (nbd0): failed to convert unwritten extents to written extents -- potential data loss!  (inode 12, error -30)
[  +0.000061] Buffer I/O error on device nbd0, logical block 36631
[  +0.000041] Buffer I/O error on device nbd0, logical block 36632
[  +0.000025] Buffer I/O error on device nbd0, logical block 36633
[  +0.001099] Buffer I/O error on dev nbd0, logical block 0, lost async page write
[  +0.000503] Buffer I/O error on device nbd0, logical block 36634
[  +0.000477] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000406] Buffer I/O error on device nbd0, logical block 36635
[  +0.000911] Buffer I/O error on device nbd0, logical block 36636
[  +0.000343] Buffer I/O error on device nbd0, logical block 36637
[  +0.000321] Buffer I/O error on device nbd0, logical block 36638
[  +0.000340] Buffer I/O error on device nbd0, logical block 36639
[  +0.000323] Buffer I/O error on device nbd0, logical block 36640
[Aug12 06:59] block nbd0: NBD_DISCONNECT
[  +0.001131] block nbd0: Send disconnect failed -32

### CASE 2:
#### What happens with 300 sec io-timeout
##### i.e. reattach-timeout == io-timeout

[Aug12 07:02] nbd0: detected capacity change from 0 to 2097152
[  +4.852686] block nbd0: NBD_DISCONNECT
[  +0.000505] block nbd0: Disconnected due to user request.
[  +0.000292] block nbd0: shutting down sockets
[  +0.000236] print_req_error: 66 callbacks suppressed
[  +0.000002] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000909] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000461] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000287] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000337] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000311] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000491] ldm_validate_partition_table(): Disk read failed.
[  +0.000332] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000327] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000614] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000374] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000641] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000425] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000323] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000317] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000388] Dev nbd0: unable to read RDB block 0
[  +0.000311] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000403] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000821] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000560] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000718]  nbd0: unable to read partition table
[  +0.000605] blk_update_request: I/O error, dev nbd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[  +0.000372] Buffer I/O error on dev nbd0, logical block 0, async page read
[  +0.000397] ldm_validate_partition_table(): Disk read failed.
[  +0.000409] Dev nbd0: unable to read RDB block 0
[  +0.000592]  nbd0: unable to read partition table
[ +45.635005] nbd0: detected capacity change from 0 to 2097152
[Aug12 07:03] EXT4-fs (nbd0): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[ +20.597204] block nbd0: Receive control failed (result -32)
[  +0.000299] block nbd0: Send control failed (result -32)
[  +0.002013] block nbd0: Request send failed, requeueing
[  +0.000841] block nbd0: Dead connection, failed to find a fallback
[Aug12 07:08] block nbd0: shutting down sockets
[  +0.000436] print_req_error: 8 callbacks suppressed
[  +0.000002] blk_update_request: I/O error, dev nbd0, sector 0 op 0x1:(WRITE) flags 0x3800 phys_seg 1 prio class 0
[  +0.000868] buffer_io_error: 8 callbacks suppressed
[  +0.000005] Buffer I/O error on dev nbd0, logical block 0, lost async page write
[  +0.001127] blk_update_request: I/O error, dev nbd0, sector 1096 op 0x1:(WRITE) flags 0x3800 phys_seg 1 prio class 0
[  +0.000375] Buffer I/O error on dev nbd0, logical block 137, lost async page write
[  +0.000442] blk_update_request: I/O error, dev nbd0, sector 33928 op 0x1:(WRITE) flags 0x3800 phys_seg 1 prio class 0
[  +0.000443] Buffer I/O error on dev nbd0, logical block 4241, lost async page write
[  +0.000584] EXT4-fs error (device nbd0): __ext4_find_entry:1611: inode #2: comm bash: reading directory lblock 0
[  +0.000012] blk_update_request: I/O error, dev nbd0, sector 638976 op 0x1:(WRITE) flags 0x4000 phys_seg 1 prio class 0
[  +0.001025] EXT4-fs (nbd0): previous I/O error to superblock detected
[  +0.000280] blk_update_request: I/O error, dev nbd0, sector 639232 op 0x1:(WRITE) flags 0x4000 phys_seg 1 prio class 0
[  +0.001139] blk_update_request: I/O error, dev nbd0, sector 639488 op 0x1:(WRITE) flags 0x4000 phys_seg 1 prio class 0
[  +0.000692] blk_update_request: I/O error, dev nbd0, sector 639744 op 0x1:(WRITE) flags 0x4000 phys_seg 1 prio class 0
[  +0.000536] blk_update_request: I/O error, dev nbd0, sector 640000 op 0x1:(WRITE) flags 0x4000 phys_seg 1 prio class 0
[  +0.000583] blk_update_request: I/O error, dev nbd0, sector 640256 op 0x1:(WRITE) flags 0x4000 phys_seg 1 prio class 0
[  +0.000550] blk_update_request: I/O error, dev nbd0, sector 640512 op 0x1:(WRITE) flags 0x4000 phys_seg 1 prio class 0
[  +0.000560] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 81920)
[  +0.000631] EXT4-fs error (device nbd0): ext4_check_bdev_write_error:215: comm kworker/u24:2: Error while async write back metadata
[  +0.000881] Buffer I/O error on dev nbd0, logical block 131087, lost sync page write
[  +0.000542] buffer_io_error: 2038 callbacks suppressed
[  +0.000003] Buffer I/O error on device nbd0, logical block 79872
[  +0.000008] Buffer I/O error on device nbd0, logical block 79873
[  +0.000001] Buffer I/O error on device nbd0, logical block 79874
[  +0.000003] Buffer I/O error on device nbd0, logical block 79875
[  +0.000001] Buffer I/O error on device nbd0, logical block 79876
[  +0.000001] Buffer I/O error on device nbd0, logical block 79877
[  +0.000002] Buffer I/O error on device nbd0, logical block 79878
[  +0.000017] Buffer I/O error on device nbd0, logical block 79879
[  +0.000001] Buffer I/O error on device nbd0, logical block 79880
[  +0.000001] Buffer I/O error on device nbd0, logical block 79881
[  +0.008731] Aborting journal on device nbd0-8.
[  +0.000001] EXT4-fs error (device nbd0): ext4_check_bdev_write_error:215: comm kworker/u24:0: Error while async write back metadata
[  +0.000026] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 83968)
[  +0.000586] Buffer I/O error on dev nbd0, logical block 131072, lost sync page write
[  +0.000863] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm kworker/u24:4: Detected aborted journal
[  +0.000810] EXT4-fs error (device nbd0) in ext4_writepages:2813: Journal has aborted
[  +0.000546] JBD2: Error -5 detected when updating journal superblock for nbd0-8.
[  +0.001493] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm dd: Detected aborted journal
[  +0.000375] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000009] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000002] EXT4-fs (nbd0): Remounting filesystem read-only
[  +0.000003] EXT4-fs (nbd0): failed to convert unwritten extents to written extents -- potential data loss!  (inode 12, error -30)
[  +0.000340] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000008] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000794] Buffer I/O error on dev nbd0, logical block 262128, async page read
[  +0.006958] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.003668] EXT4-fs (nbd0): I/O error while writing superblock
[Aug12 07:09] block nbd0: NBD_DISCONNECT
[  +0.000555] block nbd0: Send disconnect failed -32

### CASE 3:
#### What happens with 330 sec io-timeout
##### i.e. reattach-timeout < io-timeout

[Aug12 07:10] nbd0: detected capacity change from 0 to 2097152
[  +9.795010] EXT4-fs (nbd0): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[Aug12 07:12] block nbd0: Receive control failed (result -32)
[  +0.000111] block nbd0: Send control failed (result -32)
[  +0.000857] block nbd0: Request send failed, requeueing
[  +0.000491] block nbd0: Dead connection, failed to find a fallback
[Aug12 07:17] block nbd0: shutting down sockets
[  +0.000297] print_req_error: 132 callbacks suppressed
[  +0.000005] blk_update_request: I/O error, dev nbd0, sector 737792 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000682] blk_update_request: I/O error, dev nbd0, sector 738048 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000333] blk_update_request: I/O error, dev nbd0, sector 738304 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000264] blk_update_request: I/O error, dev nbd0, sector 738560 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000299] blk_update_request: I/O error, dev nbd0, sector 738816 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000302] blk_update_request: I/O error, dev nbd0, sector 739072 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000276] blk_update_request: I/O error, dev nbd0, sector 739328 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000254] blk_update_request: I/O error, dev nbd0, sector 739584 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000288] blk_update_request: I/O error, dev nbd0, sector 739840 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000266] blk_update_request: I/O error, dev nbd0, sector 740096 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000287] Buffer I/O error on dev nbd0, logical block 131090, lost sync page write
[  +0.000311] Buffer I/O error on dev nbd0, logical block 0, lost async page write
[  +0.000023] EXT4-fs error (device nbd0): ext4_check_bdev_write_error:215: comm kworker/u24:0: Error while async write back metadata
[  +0.000090] Aborting journal on device nbd0-8.
[  +0.000273] Buffer I/O error on dev nbd0, logical block 137, lost async page write
[  +0.000977] EXT4-fs (nbd0): previous I/O error to superblock detected
[  +0.000286] Buffer I/O error on dev nbd0, logical block 4241, lost async page write
[  +0.000165] EXT4-fs (nbd0): Delayed block allocation failed for inode 12 at logical offset 59392 with max blocks 2048 with error 30
[  +0.000003] EXT4-fs (nbd0): This should not happen!! Data will be lost

[  +0.000004] EXT4-fs error (device nbd0) in ext4_writepages:2813: Journal has aborted
[  +0.001278] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm kworker/u24:0: Detected aborted journal
[  +0.000230] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm dd: Detected aborted journal
[  +0.000700] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.002385] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000009] Buffer I/O error on dev nbd0, logical block 131072, lost sync page write
[  +0.000906] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 94208)
[  +0.000017] JBD2: Error -5 detected when updating journal superblock for nbd0-8.
[  +0.000359] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000006] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm kworker/u24:1: Detected aborted journal
[  +0.001052] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000020] EXT4-fs (nbd0): previous I/O error to superblock detected
[  +0.000036] EXT4-fs (nbd0): previous I/O error to superblock detected
[  +0.000039] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000034] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000001] EXT4-fs (nbd0): Remounting filesystem read-only
[  +0.000066] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000006] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.003158] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000394] buffer_io_error: 4086 callbacks suppressed
[  +0.000002] Buffer I/O error on device nbd0, logical block 92160
[  +0.000772] Buffer I/O error on device nbd0, logical block 92161
[  +0.000391] Buffer I/O error on device nbd0, logical block 92162
[  +0.000440] Buffer I/O error on device nbd0, logical block 92163
[  +0.000351] Buffer I/O error on device nbd0, logical block 92164
[  +0.000375] Buffer I/O error on device nbd0, logical block 92165
[  +0.000332] Buffer I/O error on device nbd0, logical block 92166
[  +0.000341] Buffer I/O error on device nbd0, logical block 92167
[  +0.000382] Buffer I/O error on device nbd0, logical block 92168
[  +0.000536] Buffer I/O error on device nbd0, logical block 92169
[Aug12 07:22] block nbd0: NBD_DISCONNECT
[  +0.000516] block nbd0: Send disconnect failed -32

### CASE 4: (should be same as CASE1)
#### What happens with 0 sec io-timeout
##### reattach-timeout > io-timeout

[ +13.683781] nbd0: detected capacity change from 0 to 2097152
[ +21.034455] EXT4-fs (nbd0): mounted filesystem with ordered data mode. Opts: (null). Quota mode: none.
[Aug12 07:23] block nbd0: Receive control failed (result -32)
[  +0.000030] block nbd0: Send control failed (result -32)
[  +0.002106] block nbd0: Request send failed, requeueing
[  +0.001264] block nbd0: Dead connection, failed to find a fallback
[Aug12 07:28] block nbd0: shutting down sockets
[  +0.000343] print_req_error: 71 callbacks suppressed
[  +0.000002] blk_update_request: I/O error, dev nbd0, sector 1048680 op 0x1:(WRITE) flags 0x800 phys_seg 7 prio class 0
[  +0.000639] buffer_io_error: 1 callbacks suppressed
[  +0.000002] Buffer I/O error on dev nbd0, logical block 131085, lost sync page write
[  +0.000856] blk_update_request: I/O error, dev nbd0, sector 0 op 0x1:(WRITE) flags 0x3800 phys_seg 1 prio class 0
[  +0.000014] Aborting journal on device nbd0-8.
[  +0.000024] EXT4-fs error (device nbd0): ext4_check_bdev_write_error:215: comm kworker/u24:2: Error while async write back metadata
[  +0.000339] Buffer I/O error on dev nbd0, logical block 0, lost async page write
[  +0.000015] blk_update_request: I/O error, dev nbd0, sector 1096 op 0x1:(WRITE) flags 0x3800 phys_seg 1 prio class 0
[  +0.000942] EXT4-fs error (device nbd0): ext4_check_bdev_write_error:215: comm kworker/u24:1: Error while async write back metadata
[  +0.000341] EXT4-fs (nbd0): previous I/O error to superblock detected
[  +0.000134] Buffer I/O error on dev nbd0, logical block 137, lost async page write
[  +0.000425] EXT4-fs error (device nbd0) in ext4_reserve_inode_write:5752: Journal has aborted
[  +0.000463] blk_update_request: I/O error, dev nbd0, sector 33928 op 0x1:(WRITE) flags 0x3800 phys_seg 1 prio class 0
[  +0.000658] EXT4-fs error (device nbd0): mpage_map_and_submit_extent:2509: inode #12: comm kworker/u24:1: mark_inode_dirty error
[  +0.000343] Buffer I/O error on dev nbd0, logical block 4241, lost async page write
[  +0.000402] EXT4-fs error (device nbd0): mpage_map_and_submit_extent:2511: comm kworker/u24:1: Failed to mark inode 12 dirty
[  +0.000339] blk_update_request: I/O error, dev nbd0, sector 819712 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000333] EXT4-fs error (device nbd0) in ext4_writepages:2813: Journal has aborted
[  +0.000741] blk_update_request: I/O error, dev nbd0, sector 819968 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.002085] blk_update_request: I/O error, dev nbd0, sector 820224 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000374] blk_update_request: I/O error, dev nbd0, sector 820480 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000420] blk_update_request: I/O error, dev nbd0, sector 820736 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000361] blk_update_request: I/O error, dev nbd0, sector 820992 op 0x1:(WRITE) flags 0x4000 phys_seg 2 prio class 0
[  +0.000470] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000370] Buffer I/O error on dev nbd0, logical block 131072, lost sync page write
[  +0.000007] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000507] JBD2: Error -5 detected when updating journal superblock for nbd0-8.
[  +0.000025] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 104448)
[  +0.000207] EXT4-fs warning (device nbd0): ext4_end_bio:342: I/O error 10 writing to inode 12 starting block 106496)
[  +0.000047] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm kworker/u24:1: Detected aborted journal
[  +0.000010] EXT4-fs error (device nbd0): ext4_journal_check_start:83: comm dd: Detected aborted journal
[  +0.000119] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.002584] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.001046] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000501] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000064] EXT4-fs (nbd0): previous I/O error to superblock detected
[  +0.000526] EXT4-fs (nbd0): Remounting filesystem read-only
[  +0.000382] Buffer I/O error on dev nbd0, logical block 262128, async page read
[  +0.000133] Buffer I/O error on dev nbd0, logical block 0, lost sync page write
[  +0.000600] EXT4-fs (nbd0): failed to convert unwritten extents to written extents -- potential data loss!  (inode 12, error -30)
[  +0.000546] EXT4-fs (nbd0): I/O error while writing superblock
[  +0.000556] buffer_io_error: 2038 callbacks suppressed
[  +0.000002] Buffer I/O error on device nbd0, logical block 102400
[  +0.002748] Buffer I/O error on device nbd0, logical block 102401
[  +0.000448] Buffer I/O error on device nbd0, logical block 102402
[  +0.000387] Buffer I/O error on device nbd0, logical block 102403
[  +0.000374] Buffer I/O error on device nbd0, logical block 102404
[  +0.000432] Buffer I/O error on device nbd0, logical block 102405
[  +0.000481] Buffer I/O error on device nbd0, logical block 102406
[  +0.000404] Buffer I/O error on device nbd0, logical block 102407
[  +0.000405] Buffer I/O error on device nbd0, logical block 102408
[  +0.000412] Buffer I/O error on device nbd0, logical block 102409
[  +0.001143] EXT4-fs (nbd0): failed to convert unwritten extents to written extents -- potential data loss!  (inode 12, error -30)