Comment # 2
on bug 1033098
from zhilong liu
Created attachment 720650 [details]
strace
Details steps:
zlliu:~/mdadm # ./mdadm -CR /dev/md2 -b internal -l1 -n2 /dev/loop[0-1]
--assume-clean
zlliu:~/mdadm # cat /proc/mdstat
Personalities : [multipath] [raid1] [raid6] [raid5] [raid4]
md2 : active raid1 loop1[1] loop0[0]
19968 blocks super 1.2 [2/2] [UU]
bitmap: 0/1 pages [0KB], 65536KB chunk
unused devices: <none>
You have mail in /var/mail/root
Open another terminal:
zlliu:~/mdadm # dmesg -c
zlliu:~ # strace -o /tmp/strace -s 100 -f -p 1
Process 1 attached
Process 1914 attached (this line printed after executed the grow command)
zlliu:~/mdadm # ./mdadm --grow /dev/md2 -l5 -n3 -a /dev/loop2
mdadm: level of /dev/md2 changed to raid5
mdadm: added /dev/loop2
mdadm: Need to backup 128K of critical section..
zlliu:~/mdadm # cat /proc/mdstat
Personalities : [multipath] [raid1] [raid6] [raid5] [raid4]
md2 : active raid5 loop2[2] loop1[1] loop0[0]
19968 blocks super 1.2 level 5, 64k chunk, algorithm 2 [3/3] [UUU]
[>....................] reshape = 0.0% (0/19968) finish=956.8min
speed=0K/sec
bitmap: 0/1 pages [0KB], 65536KB chunk
unused devices: <none>
zlliu:~/mdadm # ps -ef | grep raid
root 1676 2 0 10:15 ? 00:00:00 [raid5wq]
root 1905 2 0 10:31 ? 00:00:00 [md2_raid5]
root 1926 1201 0 10:31 pts/0 00:00:00 grep --color=auto raid
zlliu:~/mdadm # cat /proc/1676/stack
[<ffffffff810814bb>] rescuer_thread+0x27b/0x310
[<ffffffff81086581>] kthread+0xc1/0xe0
[<ffffffff8165f462>] ret_from_fork+0x42/0x70
[<ffffffffffffffff>] 0xffffffffffffffff
zlliu:~/mdadm # cat /proc/1905/stack
[<ffffffffa032c72b>] md_thread+0xeb/0x120 [md_mod]
[<ffffffff81086581>] kthread+0xc1/0xe0
[<ffffffff8165f462>] ret_from_fork+0x42/0x70
[<ffffffffffffffff>] 0xffffffffffffffff
zlliu:~/mdadm # cat /proc/1914/stack
cat: /proc/1914/stack: No such file or directory
zlliu:~/mdadm # dmesg -c
[ 1164.436377] md/raid:md2: device loop1 operational as raid disk 1
[ 1164.436381] md/raid:md2: device loop0 operational as raid disk 0
[ 1164.436591] md/raid:md2: allocated 2250kB
[ 1164.444087] md/raid:md2: raid level 5 active with 2 out of 2 devices,
algorithm 2
[ 1164.444089] RAID conf printout:
[ 1164.444090] --- level:5 rd:2 wd:2
[ 1164.444091] disk 0, o:1, dev:loop0
[ 1164.444092] disk 1, o:1, dev:loop1
[ 1164.444105] md/raid456: discard support disabled due to uncertainty.
[ 1164.444106] Set raid456.devices_handle_discard_safely=Y to override.
[ 1164.662276] md: bind<loop2>
[ 1165.664048] RAID conf printout:
[ 1165.664053] --- level:5 rd:3 wd:3
[ 1165.664055] disk 0, o:1, dev:loop0
[ 1165.664056] disk 1, o:1, dev:loop1
[ 1165.664058] disk 2, o:1, dev:loop2
[ 1165.668863] md: reshape of RAID array md2
[ 1165.668866] md: minimum _guaranteed_ speed: 1000 KB/sec/disk.
[ 1165.668867] md: using maximum available idle IO bandwidth (but not more than
2000 KB/sec) for reshape.
[ 1165.668869] md: using 128k window, over a total of 19968k.
zlliu:~/mdadm # journalctl -xn
-- Logs begin at Fri 2017-04-07 15:47:05 CST, end at Tue 2017-04-11 10:31:07
CST. --
Apr 11 10:31:06 zlliu kernel: md: bind<loop2>
Apr 11 10:31:07 zlliu kernel: RAID conf printout:
Apr 11 10:31:07 zlliu kernel: --- level:5 rd:3 wd:3
Apr 11 10:31:07 zlliu kernel: disk 0, o:1, dev:loop0
Apr 11 10:31:07 zlliu kernel: disk 1, o:1, dev:loop1
Apr 11 10:31:07 zlliu kernel: disk 2, o:1, dev:loop2
Apr 11 10:31:07 zlliu kernel: md: reshape of RAID array md2
Apr 11 10:31:07 zlliu kernel: md: minimum _guaranteed_ speed: 1000
KB/sec/disk.
Apr 11 10:31:07 zlliu kernel: md: using maximum available idle IO bandwidth
(but not more than 2000 KB/sec) for reshape.
Apr 11 10:31:07 zlliu kernel: md: using 128k window, over a total of 19968k.
zlliu:~/mdadm # systemctl status mdadm-grow-continue@md2.service
mdadm-grow-continue@md2.service - Manage MD Reshape on /dev/md2
Loaded: loaded (/usr/lib/systemd/system/mdadm-grow-continue@.service;
static)
Active: failed (Result: exit-code) since Tue 2017-04-11 10:31:07 CST; 5min
ago
Process: 1914 ExecStart=/sbin/mdadm --grow --continue /dev/%I (code=exited,
status=2)
Main PID: 1914 (code=exited, status=2)
Thanks,
-Zhilong