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* NFSv4 client locks up on larger writes with Kerberos enabled
@ 2019-09-18 23:36 Kevin Vasko
       [not found] ` <E172CA50-EC89-4072-9C1D-1B825DC3FE8B@lysator.liu.se>
  2019-09-25 16:48 ` bfields
  0 siblings, 2 replies; 16+ messages in thread
From: Kevin Vasko @ 2019-09-18 23:36 UTC (permalink / raw)
  To: linux-nfs

Hello,


We have a new Dell EMC Unity 300 acting as NAS Server that is
presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
but issue is also present on CentOS 7.6 systems. We have been
struggling with this issue for over a week now and not sure how to
resolve it.



We are having trouble with NFS Clients completing their writes to the
Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
Share. I created the NFS Share on the U300, associated it with our
FreeIPA (Kerberos/LDAP server) and everything shows successful.



I can mount the share without a problem on multiple Ubuntu/CentOS
machines without issues. I can ls around and move around on the share
without issue (seemingly). I can copy files as well and that seem to
work (haven’t tested it extensively as I have been heavily focused on
this issue). However, clients won't complete their writes to the NFS
share randomly once the file gets to > 2GB or so in file size.
_sometimes_ they do, but I would say anything > 3GB, the client locks
up and won’t ever return 80% of the time I try it.



For example, I can run dd and write ten 1MB files to the NFS share no
issues, all back to back to back. However, when I try to do a single
3GB file, it _might_ or might not finish. If it doesn’t finish it just
locks up the client. Sometimes it will finish though so its random.
However, I would say 70-80% of the time it is reproducible with files
> 3GB or so.



Here is some information on the client and what I’m doing to reproduce
the issue. I have tried krb5, and krb5p with the same results.
Removing the requirement for krb5 in the NFS server and mounting with
sec=none, I don’t seem to hit the issue.



$uname -a

5.0.0-27-generic #28~18.04.1-Ubuntu SMP Thu Aug 22 03:00:32 UTC 2019
x86_64 x86_64 x86_64 GNU/Linux



$mount

nfs-server.example.com:/ds1 on /data type nfs4
(rw,relatime,vers=4.1,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5p,clientaddr=10.75.40.254,local_lock=none,addr=10.75.37.2)



$ dd if=/dev/zero of=/data/test.img count=1000 bs=1000

1000+0 records in

1000+0 records out

1000000 bytes (1.0 MB, 977 KiB) copied, 0.00613671 s, 163 MB/s

$ dd if=/dev/zero of=/data/test.img bs=1000M count=6

---- HUNG ----



After it hangs it will NEVER return. The only way I've been able to
get the client to return is to go into the U300 Control panel and
change the "SP Owner:" from SPA to SPB (effectively restarting the NFS
server). Once that happens the client returns.



If I disable Kerberos on the NFS Share I have no problems writing
larger files it seems.



I did some straces of the dd and this is what I saw.



This was a successful write….



$ strace dd if=/dev/zero of=/data/test3.img bs=100M count=1

execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test3.img",
"bs=100M", "count=1"], 0x7fff8c03c7f0 /* 21 vars */) = 0

brk(NULL)                               = 0x559b8b39a000

access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)

access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)

openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=93482, ...}) = 0

mmap(NULL, 93482, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f62b6180000

close(3)                                = 0

access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)

openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3

read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
832) = 832

fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0

mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f62b617e000

mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x7f62b5b7f000

mprotect(0x7f62b5d66000, 2097152, PROT_NONE) = 0

mmap(0x7f62b5f66000, 24576, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f62b5f66000

mmap(0x7f62b5f6c000, 15072, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f62b5f6c000

close(3)                                = 0

arch_prctl(ARCH_SET_FS, 0x7f62b617f540) = 0

mprotect(0x7f62b5f66000, 16384, PROT_READ) = 0

mprotect(0x559b8978b000, 4096, PROT_READ) = 0

mprotect(0x7f62b6197000, 4096, PROT_READ) = 0

munmap(0x7f62b6180000, 93482)           = 0

rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0

rt_sigaction(SIGUSR1, {sa_handler=0x559b8957e0e0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER, sa_restorer=0x7f62b5bbdf20}, NULL, 8) = 0

rt_sigaction(SIGINT, {sa_handler=0x559b8957e0d0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
sa_restorer=0x7f62b5bbdf20}, NULL, 8) = 0

brk(NULL)                               = 0x559b8b39a000

brk(0x559b8b3bb000)                     = 0x559b8b3bb000

openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=4326016, ...}) = 0

mmap(NULL, 4326016, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f62b575e000

close(3)                                = 0

openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3

dup2(3, 0)                              = 0

close(3)                                = 0

lseek(0, 0, SEEK_CUR)                   = 0

openat(AT_FDCWD, "/data/test3.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3

dup2(3, 1)                              = 1

close(3)                                = 0

mmap(NULL, 104869888, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x7f62af35b000

read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
104857600) = 104857600

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
104857600) = 104857600

close(0)                                = 0

close(1)                                = 0

openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0

fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0

read(0, "# Locale name alias data base.\n#"..., 4096) = 2995

read(0, "", 4096)                       = 0

close(0)                                = 0

openat(AT_FDCWD,
"/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)

openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
ENOENT (No such file or directory)

openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)

openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
= -1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)

openat(AT_FDCWD,
"/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
0

fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0

mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f62b6196000

close(0)                                = 0

write(2, "1+0 records in\n1+0 records out\n", 311+0 records in

1+0 records out

) = 31

write(2, "104857600 bytes (105 MB, 100 MiB"..., 61104857600 bytes (105
MB, 100 MiB) copied, 1.01552 s, 103 MB/s) = 61

write(2, "\n", 1

)                       = 1

close(2)                                = 0

exit_group(0)                           = ?

+++ exited with 0 +++



This one was unsuccessful write and hung until I restarted the NFS server.



strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=6

execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
"bs=1000M", "count=6"], 0x7ffc8ee7e8b8 /* 30 vars */) = 0

brk(NULL)                               = 0x5648bd26a000

access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)

access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)

openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0

mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4f8dda1000

close(3)                                = 0

access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)

openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3

read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
832) = 832

fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0

mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f4f8dd9f000

mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x7f4f8d7a8000

mprotect(0x7f4f8d98f000, 2097152, PROT_NONE) = 0

mmap(0x7f4f8db8f000, 24576, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f4f8db8f000

mmap(0x7f4f8db95000, 15072, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f4f8db95000

close(3)                                = 0

arch_prctl(ARCH_SET_FS, 0x7f4f8dda0540) = 0

mprotect(0x7f4f8db8f000, 16384, PROT_READ) = 0

mprotect(0x5648bb739000, 4096, PROT_READ) = 0

mprotect(0x7f4f8ddc0000, 4096, PROT_READ) = 0

munmap(0x7f4f8dda1000, 125550)          = 0

rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0

rt_sigaction(SIGUSR1, {sa_handler=0x5648bb52c0e0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER, sa_restorer=0x7f4f8d7e6f20}, NULL, 8) = 0

rt_sigaction(SIGINT, {sa_handler=0x5648bb52c0d0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
sa_restorer=0x7f4f8d7e6f20}, NULL, 8) = 0

brk(NULL)                               = 0x5648bd26a000

brk(0x5648bd28b000)                     = 0x5648bd28b000

openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3

fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0

mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4f8cc97000

close(3)                                = 0

openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3

dup2(3, 0)                              = 0

close(3)                                = 0

lseek(0, 0, SEEK_CUR)                   = 0

openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3

dup2(3, 1)                              = 1

close(3)                                = 0

mmap(NULL, 1048588288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4f4e494000

read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000

close(0)                                = 0

close(1







I did some packet tracing and on the smaller writes, I would see a
bunch of writes and replies to those writes, the client would COMMIT
and then NFS server would reply with an ack COMMIT, client would then
issue a CLOSE, and server would respond with a CLOSE. However, on
larger writes where it would hang it would do…client would do a bunch
of writes packets, NFS server would respond to the write packets,
client would issue a COMMIT command, server would respond with a
COMMIT, and then nothing else would happen. No CLOSE would seemingly
be sent from the client, so I don’t know if the client was waiting on
the server to send back some type of message saying that the system
could issue a CLOSE or the client was never sending a CLOSE.



Once it is in the locked state, if I restart the NFS server as I
mentioned above the close(1…will continue and finish the write and
exit normally.



I did a kernel Stack Traceback on the NFS client (the light weight
version of just printing out /proc/*/wchan) while the dd command was
stuck in the “close(1” and the process for the dd command just says.



Process /proc/32161/wchan

ep_poll



I also enabled the NFS debugging and while its stuck it just keep
repeating the bottom section.



Sep 19 06:25:19 examplehost kernel: [772614.270750] NFS:       commit
(0:52/9439 4096@4609744896) OK

Sep 19 06:25:19 examplehost kernel: [772614.270751] NFS:       commit
(0:52/9439 4096@4609748992) OK

Sep 19 06:25:19 examplehost kernel: [772614.270754] NFS:       commit
(0:52/9439 4096@4609753088) OK

Sep 19 06:25:19 examplehost kernel: [772614.270757] NFS:       commit
(0:52/9439 4096@4609757184) OK

Sep 19 06:25:19 examplehost kernel: [772614.270759] NFS:       commit
(0:52/9439 4096@4609761280) OK

Sep 19 06:25:19 examplehost kernel: [772614.270761] NFS:       commit
(0:52/9439 4096@4609765376) OK

Sep 19 06:25:19 examplehost kernel: [772614.270763] NFS:       commit
(0:52/9439 4096@4609769472) OK

Sep 19 06:25:19 examplehost kernel: [772614.270767] NFS:       commit
(0:52/9439 4096@4609773568) OK

Sep 19 06:25:19 examplehost kernel: [772614.270769] NFS:       commit
(0:52/9439 4096@4609777664) OK

Sep 19 06:25:19 examplehost kernel: [772614.270772] NFS:       commit
(0:52/9439 4096@4609781760) OK

Sep 19 06:25:19 examplehost kernel: [772614.270773] NFS:       commit
(0:52/9439 4096@4609785856) OK

Sep 19 06:25:19 examplehost kernel: [772614.270775] NFS:       commit
(0:52/9439 4096@4609789952) OK

Sep 19 06:25:19 examplehost kernel: [772614.270777] NFS:       commit
(0:52/9439 4096@4609794048) OK

Sep 19 06:25:19 examplehost kernel: [772614.270781] NFS:       commit
(0:52/9439 4096@4609798144) OK

Sep 19 06:25:31 examplehost kernel: [772626.175927] <--
nfs41_proc_async_sequence status=0

Sep 19 06:25:31 examplehost kernel: [772626.176018] encode_sequence:
sessionid=61:1568410703:305419896:61 seqid=2907 slotid=0 max_slotid=35
cache_this=0

Sep 19 06:25:31 examplehost kernel: [772626.176572]
nfs41_sequence_process: Error 0 free the slot

Sep 19 06:25:31 examplehost kernel: [772626.176576]
nfs41_sequence_call_done rpc_cred 000000004b01718a

Sep 19 06:25:31 examplehost kernel: [772626.176577] <-- nfs41_sequence_call_done

Sep 19 06:25:43 examplehost kernel: [772638.207976] <--
nfs41_proc_async_sequence status=0

Sep 19 06:25:43 examplehost kernel: [772638.208074] encode_sequence:
sessionid=61:1568410703:305419896:61 seqid=2908 slotid=0 max_slotid=35
cache_this=0

Sep 19 06:25:43 examplehost kernel: [772638.208642]
nfs41_sequence_process: Error 0 free the slot

Sep 19 06:25:43 examplehost kernel: [772638.208646]
nfs41_sequence_call_done rpc_cred 000000004b01718a

Sep 19 06:25:43 examplehost kernel: [772638.208648] <-- nfs41_sequence_call_done

Sep 19 06:25:55 examplehost kernel: [772650.240046] <--
nfs41_proc_async_sequence status=0

Sep 19 06:25:55 examplehost kernel: [772650.240129] encode_sequence:
sessionid=61:1568410703:305419896:61 seqid=2909 slotid=0 max_slotid=35
cache_this=0

Sep 19 06:25:55 examplehost kernel: [772650.240904]
nfs41_sequence_process: Error 0 free the slot

Sep 19 06:25:55 examplehost kernel: [772650.240908]
nfs41_sequence_call_done rpc_cred 000000004b01718a

Sep 19 06:25:55 examplehost kernel: [772650.240909] <-- nfs41_sequence_call_done





On a small file that actually completes it looks like this…



Sep 19 06:13:29 examplehost kernel: [771904.532059] NFS:       commit
(0:52/9439 4096@7409315840) OK

Sep 19 06:13:29 examplehost kernel: [771904.532061] NFS:       commit
(0:52/9439 4096@7409319936) OK

Sep 19 06:13:29 examplehost kernel: [771904.532064] NFS:       commit
(0:52/9439 4096@7409324032) OK

Sep 19 06:13:29 examplehost kernel: [771904.532066] NFS:       commit
(0:52/9439 4096@7409328128) OK

Sep 19 06:13:29 examplehost kernel: [771904.532069] NFS:       commit
(0:52/9439 4096@7409332224) OK

Sep 19 06:13:29 examplehost kernel: [771904.532071] NFS:       commit
(0:52/9439 4096@7409336320) OK

Sep 19 06:13:29 examplehost kernel: [771904.532073] NFS:       commit
(0:52/9439 4096@7409340416) OK

Sep 19 06:13:29 examplehost kernel: [771904.532076] NFS:       commit
(0:52/9439 4096@7409344512) OK

Sep 19 06:13:29 examplehost kernel: [771904.532078] NFS:       commit
(0:52/9439 4096@7409348608) OK

Sep 19 06:13:29 examplehost kernel: [771904.532081] NFS:       commit
(0:52/9439 4096@7409352704) OK

Sep 19 06:13:29 examplehost kernel: [771904.532083] NFS:       commit
(0:52/9439 4096@7409356800) OK

Sep 19 06:13:29 examplehost kernel: [771904.532086] NFS:       commit
(0:52/9439 4096@7409360896) OK

Sep 19 06:13:29 examplehost kernel: [771904.532088] NFS:       commit
(0:52/9439 4096@7409364992) OK

Sep 19 06:13:29 examplehost kernel: [771904.532090] NFS:       commit
(0:52/9439 4096@7409369088) OK

Sep 19 06:13:29 examplehost kernel: [771904.532093] NFS:       commit
(0:52/9439 4096@7409373184) OK

Sep 19 06:13:29 examplehost kernel: [771904.532171] NFS: release(/test.img)

Sep 19 06:13:29 examplehost kernel: [771904.532193] nfs4_close_prepare: begin!

Sep 19 06:13:29 examplehost kernel: [771904.532197] nfs4_close_prepare: done!

Sep 19 06:13:29 examplehost kernel: [771904.532235] encode_sequence:
sessionid=61:1568410703:305419896:61 seqid=6 slotid=0 max_slotid=0
cache_this=1

Sep 19 06:13:29 examplehost kernel: [771904.532525] nfs4_close_done: begin!

Sep 19 06:13:29 examplehost kernel: [771904.532528]
nfs41_sequence_process: Error 0 free the slot

Sep 19 06:13:29 examplehost kernel: [771904.532531] nfs4_close_done:
done, ret = 0!

Sep 19 06:13:29 examplehost kernel: [771904.532555] NFS:
dentry_delete(/test.img, 48084c)

Sep 19 06:13:41 examplehost kernel: [771916.540491] <--
nfs41_proc_async_sequence status=0

Sep 19 06:13:41 examplehost kernel: [771916.540586] encode_sequence:
sessionid=61:1568410703:305419896:61 seqid=7 slotid=0 max_slotid=0
cache_this=0

Sep 19 06:13:41 examplehost kernel: [771916.541182]
nfs41_sequence_process: Error 0 free the slot

Sep 19 06:13:41 examplehost kernel: [771916.541186]
nfs41_sequence_call_done rpc_cred 000000004b01718a

Sep 19 06:13:41 examplehost kernel: [771916.541187] <-- nfs41_sequence_call_done

Sep 19 06:13:53 examplehost kernel: [771928.572599] <--
nfs41_proc_async_sequence status=0

Sep 19 06:13:53 examplehost kernel: [771928.572675] encode_sequence:
sessionid=61:1568410703:305419896:61 seqid=8 slotid=0 max_slotid=0
cache_this=0

Sep 19 06:13:53 examplehost kernel: [771928.572895] encode_sequence:
sessionid=61:1568410703:305419896:61 seqid=2 slotid=1 max_slotid=1
cache_this=1

Sep 19 06:13:53 examplehost kernel: [771928.573163]
nfs41_sequence_process: Error 0 free the slot

Sep 19 06:13:53 examplehost kernel: [771928.573166]
nfs41_sequence_call_done rpc_cred 000000004b01718a

Sep 19 06:13:53 examplehost kernel: [771928.573167] <-- nfs41_sequence_call_done

Sep 19 06:13:53 examplehost kernel: [771928.573236] decode_attr_type: type=00

Sep 19 06:13:53 examplehost kernel: [771928.573238]
decode_attr_change: change attribute=6738121685800950864

Sep 19 06:13:53 examplehost kernel: [771928.573240] decode_attr_size:
file size=8388608000

Sep 19 06:13:53 examplehost kernel: [771928.573242] decode_attr_fsid:
fsid=(0x0/0x0)

Sep 19 06:13:53 examplehost kernel: [771928.573243] decode_attr_fileid: fileid=0

Sep 19 06:13:53 examplehost kernel: [771928.573245]
decode_attr_fs_locations: fs_locations done, error = 0

Sep 19 06:13:53 examplehost kernel: [771928.573246] decode_attr_mode:
file mode=00



As you can see the NFS: release(/test.img) is immediately after all of
the writes on the successful version. In the version that gets stuck
it never responds with that “release”.



It’s hard for me to do any debugging on the NFS Server sinces its more
of a “managed” box (e.g I don’t have root and only have access to
certain debugging utilities). I do have a ticket open with Dell and
their engineering team is looking at this but I’m trying anything I
can do to figure this out as soon as I can.




Any help on this matter would be appreciated.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
       [not found] ` <E172CA50-EC89-4072-9C1D-1B825DC3FE8B@lysator.liu.se>
@ 2019-09-19 14:19   ` Kevin Vasko
       [not found]     ` <72E82F62-C743-4783-B81E-98E6A8E35738@lysator.liu.se>
  0 siblings, 1 reply; 16+ messages in thread
From: Kevin Vasko @ 2019-09-19 14:19 UTC (permalink / raw)
  To: Peter Eriksson, linux-nfs

Unfortunately, I haven’t seen rpc.gssd crash anywhere in the logs.

Just to confirm though I stopped rpc-gssd and started it manually in the foreground with

sudo rpc.gssd -f -vvv -rrr

Unmounted the share, mounted it again. Saw a bunch of logs and authentications seemingly

I then produced a lockup. It did some authentication in the logs and did not crash. The only warning is 

WARNING: gssd_clnt_gssd_cb: failed reading request

Googling that warning doesn’t produce much information and seems unrelated.

My keys when I do klist 

This shows they expire 24h in the future for both  my user and the NFS server. Not sure how refreshing the tickets would help in this case. In addition, if it’s locked, I restart the nfs server and then the client will immediately finish that write. I can then immediately transfer a 1MB file and it will complete successfully immediately. So if it was a kerberos ticket was expiring I would assume it wouldn’t work with the small file immediately after it just failed.

I’m using sssd so it refreshes the tickets basically every time I login to the NFS client.

-Kevin

> On Sep 19, 2019, at 6:38 AM, Peter Eriksson <pen@lysator.liu.se> wrote:
> 
> Have you verified that the “rpc.gssd” daemon doesn’t crash while the write is under way? We’ve seen problems possibly related to it (or gssproxy) with Linux clients connecting to our NFS Servers (FreeBSD-based) with NFSv4 & sec=krb5. Sometimes you might not notice it crashing due to it being restarted automatically… 
> 
> When things go south for us the Linux client “locks” up and processes end up in “device wait” and are unkillable. Only way out so far has been to reboot the client. _Sometimes_ it might be related to Kerberos tickets expiring - things _seems_ to work better here when we created a hack that renews them automatically (for as long as they can).
> 
> - Peter
> 
> 
>> On 19 Sep 2019, at 01:36, Kevin Vasko <kvasko@gmail.com> wrote:
>> 
>> Hello,
>> 
>> 
>> We have a new Dell EMC Unity 300 acting as NAS Server that is
>> presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
>> but issue is also present on CentOS 7.6 systems. We have been
>> struggling with this issue for over a week now and not sure how to
>> resolve it.
>> 
>> 
>> 
>> We are having trouble with NFS Clients completing their writes to the
>> Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
>> Share. I created the NFS Share on the U300, associated it with our
>> FreeIPA (Kerberos/LDAP server) and everything shows successful.
>> 
>> 
>> 
>> I can mount the share without a problem on multiple Ubuntu/CentOS
>> machines without issues. I can ls around and move around on the share
>> without issue (seemingly). I can copy files as well and that seem to
>> work (haven’t tested it extensively as I have been heavily focused on
>> this issue). However, clients won't complete their writes to the NFS
>> share randomly once the file gets to > 2GB or so in file size.
>> _sometimes_ they do, but I would say anything > 3GB, the client locks
>> up and won’t ever return 80% of the time I try it.
>> 
>> 
>> 
>> For example, I can run dd and write ten 1MB files to the NFS share no
>> issues, all back to back to back. However, when I try to do a single
>> 3GB file, it _might_ or might not finish. If it doesn’t finish it just
>> locks up the client. Sometimes it will finish though so its random.
>> However, I would say 70-80% of the time it is reproducible with files
>>> 3GB or so.
>> 
>> 
>> 
>> Here is some information on the client and what I’m doing to reproduce
>> the issue. I have tried krb5, and krb5p with the same results.
>> Removing the requirement for krb5 in the NFS server and mounting with
>> sec=none, I don’t seem to hit the issue.
>> 
>> 
>> 
>> $uname -a
>> 
>> 5.0.0-27-generic #28~18.04.1-Ubuntu SMP Thu Aug 22 03:00:32 UTC 2019
>> x86_64 x86_64 x86_64 GNU/Linux
>> 
>> 
>> 
>> $mount
>> 
>> nfs-server.example.com:/ds1 on /data type nfs4
>> (rw,relatime,vers=4.1,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5p,clientaddr=10.75.40.254,local_lock=none,addr=10.75.37.2)
>> 
>> 
>> 
>> $ dd if=/dev/zero of=/data/test.img count=1000 bs=1000
>> 
>> 1000+0 records in
>> 
>> 1000+0 records out
>> 
>> 1000000 bytes (1.0 MB, 977 KiB) copied, 0.00613671 s, 163 MB/s
>> 
>> $ dd if=/dev/zero of=/data/test.img bs=1000M count=6
>> 
>> ---- HUNG ----
>> 
>> 
>> 
>> After it hangs it will NEVER return. The only way I've been able to
>> get the client to return is to go into the U300 Control panel and
>> change the "SP Owner:" from SPA to SPB (effectively restarting the NFS
>> server). Once that happens the client returns.
>> 
>> 
>> 
>> If I disable Kerberos on the NFS Share I have no problems writing
>> larger files it seems.
>> 
>> 
>> 
>> I did some straces of the dd and this is what I saw.
>> 
>> 
>> 
>> This was a successful write….
>> 
>> 
>> 
>> $ strace dd if=/dev/zero of=/data/test3.img bs=100M count=1
>> 
>> execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test3.img",
>> "bs=100M", "count=1"], 0x7fff8c03c7f0 /* 21 vars */) = 0
>> 
>> brk(NULL)                               = 0x559b8b39a000
>> 
>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>> 
>> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
>> 
>> fstat(3, {st_mode=S_IFREG|0644, st_size=93482, ...}) = 0
>> 
>> mmap(NULL, 93482, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f62b6180000
>> 
>> close(3)                                = 0
>> 
>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
>> 
>> read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
>> 832) = 832
>> 
>> fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
>> 
>> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>> 0) = 0x7f62b617e000
>> 
>> mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0x7f62b5b7f000
>> 
>> mprotect(0x7f62b5d66000, 2097152, PROT_NONE) = 0
>> 
>> mmap(0x7f62b5f66000, 24576, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f62b5f66000
>> 
>> mmap(0x7f62b5f6c000, 15072, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f62b5f6c000
>> 
>> close(3)                                = 0
>> 
>> arch_prctl(ARCH_SET_FS, 0x7f62b617f540) = 0
>> 
>> mprotect(0x7f62b5f66000, 16384, PROT_READ) = 0
>> 
>> mprotect(0x559b8978b000, 4096, PROT_READ) = 0
>> 
>> mprotect(0x7f62b6197000, 4096, PROT_READ) = 0
>> 
>> munmap(0x7f62b6180000, 93482)           = 0
>> 
>> rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
>> 
>> rt_sigaction(SIGUSR1, {sa_handler=0x559b8957e0e0, sa_mask=[INT USR1],
>> sa_flags=SA_RESTORER, sa_restorer=0x7f62b5bbdf20}, NULL, 8) = 0
>> 
>> rt_sigaction(SIGINT, {sa_handler=0x559b8957e0d0, sa_mask=[INT USR1],
>> sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
>> sa_restorer=0x7f62b5bbdf20}, NULL, 8) = 0
>> 
>> brk(NULL)                               = 0x559b8b39a000
>> 
>> brk(0x559b8b3bb000)                     = 0x559b8b3bb000
>> 
>> openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
>> 
>> fstat(3, {st_mode=S_IFREG|0644, st_size=4326016, ...}) = 0
>> 
>> mmap(NULL, 4326016, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f62b575e000
>> 
>> close(3)                                = 0
>> 
>> openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
>> 
>> dup2(3, 0)                              = 0
>> 
>> close(3)                                = 0
>> 
>> lseek(0, 0, SEEK_CUR)                   = 0
>> 
>> openat(AT_FDCWD, "/data/test3.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
>> 
>> dup2(3, 1)                              = 1
>> 
>> close(3)                                = 0
>> 
>> mmap(NULL, 104869888, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
>> -1, 0) = 0x7f62af35b000
>> 
>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 104857600) = 104857600
>> 
>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 104857600) = 104857600
>> 
>> close(0)                                = 0
>> 
>> close(1)                                = 0
>> 
>> openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
>> 
>> fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
>> 
>> read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
>> 
>> read(0, "", 4096)                       = 0
>> 
>> close(0)                                = 0
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
>> -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
>> -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
>> O_RDONLY) = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
>> ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
>> O_RDONLY) = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
>> O_RDONLY) = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
>> O_RDONLY) = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
>> O_RDONLY) = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
>> = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
>> O_RDONLY) = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
>> O_RDONLY) = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD,
>> "/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
>> 0
>> 
>> fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
>> 
>> mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f62b6196000
>> 
>> close(0)                                = 0
>> 
>> write(2, "1+0 records in\n1+0 records out\n", 311+0 records in
>> 
>> 1+0 records out
>> 
>> ) = 31
>> 
>> write(2, "104857600 bytes (105 MB, 100 MiB"..., 61104857600 bytes (105
>> MB, 100 MiB) copied, 1.01552 s, 103 MB/s) = 61
>> 
>> write(2, "\n", 1
>> 
>> )                       = 1
>> 
>> close(2)                                = 0
>> 
>> exit_group(0)                           = ?
>> 
>> +++ exited with 0 +++
>> 
>> 
>> 
>> This one was unsuccessful write and hung until I restarted the NFS server.
>> 
>> 
>> 
>> strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=6
>> 
>> execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
>> "bs=1000M", "count=6"], 0x7ffc8ee7e8b8 /* 30 vars */) = 0
>> 
>> brk(NULL)                               = 0x5648bd26a000
>> 
>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>> 
>> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
>> 
>> fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
>> 
>> mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4f8dda1000
>> 
>> close(3)                                = 0
>> 
>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>> 
>> openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
>> 
>> read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
>> 832) = 832
>> 
>> fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
>> 
>> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>> 0) = 0x7f4f8dd9f000
>> 
>> mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>> 0) = 0x7f4f8d7a8000
>> 
>> mprotect(0x7f4f8d98f000, 2097152, PROT_NONE) = 0
>> 
>> mmap(0x7f4f8db8f000, 24576, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f4f8db8f000
>> 
>> mmap(0x7f4f8db95000, 15072, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f4f8db95000
>> 
>> close(3)                                = 0
>> 
>> arch_prctl(ARCH_SET_FS, 0x7f4f8dda0540) = 0
>> 
>> mprotect(0x7f4f8db8f000, 16384, PROT_READ) = 0
>> 
>> mprotect(0x5648bb739000, 4096, PROT_READ) = 0
>> 
>> mprotect(0x7f4f8ddc0000, 4096, PROT_READ) = 0
>> 
>> munmap(0x7f4f8dda1000, 125550)          = 0
>> 
>> rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
>> 
>> rt_sigaction(SIGUSR1, {sa_handler=0x5648bb52c0e0, sa_mask=[INT USR1],
>> sa_flags=SA_RESTORER, sa_restorer=0x7f4f8d7e6f20}, NULL, 8) = 0
>> 
>> rt_sigaction(SIGINT, {sa_handler=0x5648bb52c0d0, sa_mask=[INT USR1],
>> sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
>> sa_restorer=0x7f4f8d7e6f20}, NULL, 8) = 0
>> 
>> brk(NULL)                               = 0x5648bd26a000
>> 
>> brk(0x5648bd28b000)                     = 0x5648bd28b000
>> 
>> openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
>> 
>> fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
>> 
>> mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4f8cc97000
>> 
>> close(3)                                = 0
>> 
>> openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
>> 
>> dup2(3, 0)                              = 0
>> 
>> close(3)                                = 0
>> 
>> lseek(0, 0, SEEK_CUR)                   = 0
>> 
>> openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
>> 
>> dup2(3, 1)                              = 1
>> 
>> close(3)                                = 0
>> 
>> mmap(NULL, 1048588288, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4f4e494000
>> 
>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>> 1048576000) = 1048576000
>> 
>> close(0)                                = 0
>> 
>> close(1
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> I did some packet tracing and on the smaller writes, I would see a
>> bunch of writes and replies to those writes, the client would COMMIT
>> and then NFS server would reply with an ack COMMIT, client would then
>> issue a CLOSE, and server would respond with a CLOSE. However, on
>> larger writes where it would hang it would do…client would do a bunch
>> of writes packets, NFS server would respond to the write packets,
>> client would issue a COMMIT command, server would respond with a
>> COMMIT, and then nothing else would happen. No CLOSE would seemingly
>> be sent from the client, so I don’t know if the client was waiting on
>> the server to send back some type of message saying that the system
>> could issue a CLOSE or the client was never sending a CLOSE.
>> 
>> 
>> 
>> Once it is in the locked state, if I restart the NFS server as I
>> mentioned above the close(1…will continue and finish the write and
>> exit normally.
>> 
>> 
>> 
>> I did a kernel Stack Traceback on the NFS client (the light weight
>> version of just printing out /proc/*/wchan) while the dd command was
>> stuck in the “close(1” and the process for the dd command just says.
>> 
>> 
>> 
>> Process /proc/32161/wchan
>> 
>> ep_poll
>> 
>> 
>> 
>> I also enabled the NFS debugging and while its stuck it just keep
>> repeating the bottom section.
>> 
>> 
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270750] NFS:       commit
>> (0:52/9439 4096@4609744896) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270751] NFS:       commit
>> (0:52/9439 4096@4609748992) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270754] NFS:       commit
>> (0:52/9439 4096@4609753088) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270757] NFS:       commit
>> (0:52/9439 4096@4609757184) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270759] NFS:       commit
>> (0:52/9439 4096@4609761280) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270761] NFS:       commit
>> (0:52/9439 4096@4609765376) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270763] NFS:       commit
>> (0:52/9439 4096@4609769472) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270767] NFS:       commit
>> (0:52/9439 4096@4609773568) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270769] NFS:       commit
>> (0:52/9439 4096@4609777664) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270772] NFS:       commit
>> (0:52/9439 4096@4609781760) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270773] NFS:       commit
>> (0:52/9439 4096@4609785856) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270775] NFS:       commit
>> (0:52/9439 4096@4609789952) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270777] NFS:       commit
>> (0:52/9439 4096@4609794048) OK
>> 
>> Sep 19 06:25:19 examplehost kernel: [772614.270781] NFS:       commit
>> (0:52/9439 4096@4609798144) OK
>> 
>> Sep 19 06:25:31 examplehost kernel: [772626.175927] <--
>> nfs41_proc_async_sequence status=0
>> 
>> Sep 19 06:25:31 examplehost kernel: [772626.176018] encode_sequence:
>> sessionid=61:1568410703:305419896:61 seqid=2907 slotid=0 max_slotid=35
>> cache_this=0
>> 
>> Sep 19 06:25:31 examplehost kernel: [772626.176572]
>> nfs41_sequence_process: Error 0 free the slot
>> 
>> Sep 19 06:25:31 examplehost kernel: [772626.176576]
>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>> 
>> Sep 19 06:25:31 examplehost kernel: [772626.176577] <-- nfs41_sequence_call_done
>> 
>> Sep 19 06:25:43 examplehost kernel: [772638.207976] <--
>> nfs41_proc_async_sequence status=0
>> 
>> Sep 19 06:25:43 examplehost kernel: [772638.208074] encode_sequence:
>> sessionid=61:1568410703:305419896:61 seqid=2908 slotid=0 max_slotid=35
>> cache_this=0
>> 
>> Sep 19 06:25:43 examplehost kernel: [772638.208642]
>> nfs41_sequence_process: Error 0 free the slot
>> 
>> Sep 19 06:25:43 examplehost kernel: [772638.208646]
>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>> 
>> Sep 19 06:25:43 examplehost kernel: [772638.208648] <-- nfs41_sequence_call_done
>> 
>> Sep 19 06:25:55 examplehost kernel: [772650.240046] <--
>> nfs41_proc_async_sequence status=0
>> 
>> Sep 19 06:25:55 examplehost kernel: [772650.240129] encode_sequence:
>> sessionid=61:1568410703:305419896:61 seqid=2909 slotid=0 max_slotid=35
>> cache_this=0
>> 
>> Sep 19 06:25:55 examplehost kernel: [772650.240904]
>> nfs41_sequence_process: Error 0 free the slot
>> 
>> Sep 19 06:25:55 examplehost kernel: [772650.240908]
>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>> 
>> Sep 19 06:25:55 examplehost kernel: [772650.240909] <-- nfs41_sequence_call_done
>> 
>> 
>> 
>> 
>> 
>> On a small file that actually completes it looks like this…
>> 
>> 
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532059] NFS:       commit
>> (0:52/9439 4096@7409315840) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532061] NFS:       commit
>> (0:52/9439 4096@7409319936) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532064] NFS:       commit
>> (0:52/9439 4096@7409324032) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532066] NFS:       commit
>> (0:52/9439 4096@7409328128) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532069] NFS:       commit
>> (0:52/9439 4096@7409332224) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532071] NFS:       commit
>> (0:52/9439 4096@7409336320) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532073] NFS:       commit
>> (0:52/9439 4096@7409340416) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532076] NFS:       commit
>> (0:52/9439 4096@7409344512) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532078] NFS:       commit
>> (0:52/9439 4096@7409348608) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532081] NFS:       commit
>> (0:52/9439 4096@7409352704) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532083] NFS:       commit
>> (0:52/9439 4096@7409356800) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532086] NFS:       commit
>> (0:52/9439 4096@7409360896) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532088] NFS:       commit
>> (0:52/9439 4096@7409364992) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532090] NFS:       commit
>> (0:52/9439 4096@7409369088) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532093] NFS:       commit
>> (0:52/9439 4096@7409373184) OK
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532171] NFS: release(/test.img)
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532193] nfs4_close_prepare: begin!
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532197] nfs4_close_prepare: done!
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532235] encode_sequence:
>> sessionid=61:1568410703:305419896:61 seqid=6 slotid=0 max_slotid=0
>> cache_this=1
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532525] nfs4_close_done: begin!
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532528]
>> nfs41_sequence_process: Error 0 free the slot
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532531] nfs4_close_done:
>> done, ret = 0!
>> 
>> Sep 19 06:13:29 examplehost kernel: [771904.532555] NFS:
>> dentry_delete(/test.img, 48084c)
>> 
>> Sep 19 06:13:41 examplehost kernel: [771916.540491] <--
>> nfs41_proc_async_sequence status=0
>> 
>> Sep 19 06:13:41 examplehost kernel: [771916.540586] encode_sequence:
>> sessionid=61:1568410703:305419896:61 seqid=7 slotid=0 max_slotid=0
>> cache_this=0
>> 
>> Sep 19 06:13:41 examplehost kernel: [771916.541182]
>> nfs41_sequence_process: Error 0 free the slot
>> 
>> Sep 19 06:13:41 examplehost kernel: [771916.541186]
>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>> 
>> Sep 19 06:13:41 examplehost kernel: [771916.541187] <-- nfs41_sequence_call_done
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.572599] <--
>> nfs41_proc_async_sequence status=0
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.572675] encode_sequence:
>> sessionid=61:1568410703:305419896:61 seqid=8 slotid=0 max_slotid=0
>> cache_this=0
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.572895] encode_sequence:
>> sessionid=61:1568410703:305419896:61 seqid=2 slotid=1 max_slotid=1
>> cache_this=1
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573163]
>> nfs41_sequence_process: Error 0 free the slot
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573166]
>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573167] <-- nfs41_sequence_call_done
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573236] decode_attr_type: type=00
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573238]
>> decode_attr_change: change attribute=6738121685800950864
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573240] decode_attr_size:
>> file size=8388608000
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573242] decode_attr_fsid:
>> fsid=(0x0/0x0)
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573243] decode_attr_fileid: fileid=0
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573245]
>> decode_attr_fs_locations: fs_locations done, error = 0
>> 
>> Sep 19 06:13:53 examplehost kernel: [771928.573246] decode_attr_mode:
>> file mode=00
>> 
>> 
>> 
>> As you can see the NFS: release(/test.img) is immediately after all of
>> the writes on the successful version. In the version that gets stuck
>> it never responds with that “release”.
>> 
>> 
>> 
>> It’s hard for me to do any debugging on the NFS Server sinces its more
>> of a “managed” box (e.g I don’t have root and only have access to
>> certain debugging utilities). I do have a ticket open with Dell and
>> their engineering team is looking at this but I’m trying anything I
>> can do to figure this out as soon as I can.
>> 
>> 
>> 
>> 
>> Any help on this matter would be appreciated.
> 

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
       [not found]     ` <72E82F62-C743-4783-B81E-98E6A8E35738@lysator.liu.se>
@ 2019-09-19 14:58       ` Kevin Vasko
  0 siblings, 0 replies; 16+ messages in thread
From: Kevin Vasko @ 2019-09-19 14:58 UTC (permalink / raw)
  To: Peter Eriksson, linux-nfs

Yeah I appreciate the suggestion, worth a check.

Yeah this problem happens almost every single time I perform a file write to the NFS. It all started and happened as soon as I set it up. I finished setting up the server, installed the packages on the clients. Copied some small configs over to the NFS to make sure permissions were working. That worked fine. I started copying the anaconda package over which was about 500MB. After about 5 minutes and it still wasn’t wasn’t done. These systems are all on 10Gbps networks so I knew something was amiss. At that point started digging into and now a week and a half later here I am.

This problem has been a total pain in my rear and I’m scraping the bottom of the barrel of what I know to check so really anything is good for me haha. 

Thanks! 

-Kevin

> On Sep 19, 2019, at 9:40 AM, Peter Eriksson <pen@lysator.liu.se> wrote:
> 
> Yeah, it’s probably not that. But I thought you might wanna keep an eye out for that just in case. When gssd crashed for us it just silently died. No traces in log files. We just noticed it because it suddenly had a different process number. 
> 
> In our case Puppet, which runs every 30 minutes, would detect that it was down and restart the process. A debug of it pointed to a strcmp() being done on a NULL pointer. It didn’t happen every time, on a machine that mounted ~10 different NFS Servers every minute 24/7 (via both IPv4 and IPv6) it happened perhaps once per week or month or so. So not very often. We only noticed it since there would be gaps it the latency test graphs produced by those machines (measures the time it takes to mount an NFS share) :-)
> 
> 
> We do se hanging NFS-related processes on some Ubuntu 18 machines here though (without crashing gssd’s which a co-worker is investigating.
> 
> - Peter
> 
> 
>> On 19 Sep 2019, at 16:19, Kevin Vasko <kvasko@gmail.com> wrote:
>> 
>> Unfortunately, I haven’t seen rpc.gssd crash anywhere in the logs.
>> 
>> Just to confirm though I stopped rpc-gssd and started it manually in the foreground with
>> 
>> sudo rpc.gssd -f -vvv -rrr
>> 
>> Unmounted the share, mounted it again. Saw a bunch of logs and authentications seemingly
>> 
>> I then produced a lockup. It did some authentication in the logs and did not crash. The only warning is 
>> 
>> WARNING: gssd_clnt_gssd_cb: failed reading request
>> 
>> Googling that warning doesn’t produce much information and seems unrelated.
>> 
>> My keys when I do klist 
>> 
>> This shows they expire 24h in the future for both  my user and the NFS server. Not sure how refreshing the tickets would help in this case. In addition, if it’s locked, I restart the nfs server and then the client will immediately finish that write. I can then immediately transfer a 1MB file and it will complete successfully immediately. So if it was a kerberos ticket was expiring I would assume it wouldn’t work with the small file immediately after it just failed.
>> 
>> I’m using sssd so it refreshes the tickets basically every time I login to the NFS client.
>> 
>> -Kevin
>> 
>>> On Sep 19, 2019, at 6:38 AM, Peter Eriksson <pen@lysator.liu.se> wrote:
>>> 
>>> Have you verified that the “rpc.gssd” daemon doesn’t crash while the write is under way? We’ve seen problems possibly related to it (or gssproxy) with Linux clients connecting to our NFS Servers (FreeBSD-based) with NFSv4 & sec=krb5. Sometimes you might not notice it crashing due to it being restarted automatically… 
>>> 
>>> When things go south for us the Linux client “locks” up and processes end up in “device wait” and are unkillable. Only way out so far has been to reboot the client. _Sometimes_ it might be related to Kerberos tickets expiring - things _seems_ to work better here when we created a hack that renews them automatically (for as long as they can).
>>> 
>>> - Peter
>>> 
>>> 
>>>> On 19 Sep 2019, at 01:36, Kevin Vasko <kvasko@gmail.com> wrote:
>>>> 
>>>> Hello,
>>>> 
>>>> 
>>>> We have a new Dell EMC Unity 300 acting as NAS Server that is
>>>> presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
>>>> but issue is also present on CentOS 7.6 systems. We have been
>>>> struggling with this issue for over a week now and not sure how to
>>>> resolve it.
>>>> 
>>>> 
>>>> 
>>>> We are having trouble with NFS Clients completing their writes to the
>>>> Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
>>>> Share. I created the NFS Share on the U300, associated it with our
>>>> FreeIPA (Kerberos/LDAP server) and everything shows successful.
>>>> 
>>>> 
>>>> 
>>>> I can mount the share without a problem on multiple Ubuntu/CentOS
>>>> machines without issues. I can ls around and move around on the share
>>>> without issue (seemingly). I can copy files as well and that seem to
>>>> work (haven’t tested it extensively as I have been heavily focused on
>>>> this issue). However, clients won't complete their writes to the NFS
>>>> share randomly once the file gets to > 2GB or so in file size.
>>>> _sometimes_ they do, but I would say anything > 3GB, the client locks
>>>> up and won’t ever return 80% of the time I try it.
>>>> 
>>>> 
>>>> 
>>>> For example, I can run dd and write ten 1MB files to the NFS share no
>>>> issues, all back to back to back. However, when I try to do a single
>>>> 3GB file, it _might_ or might not finish. If it doesn’t finish it just
>>>> locks up the client. Sometimes it will finish though so its random.
>>>> However, I would say 70-80% of the time it is reproducible with files
>>>>> 3GB or so.
>>>> 
>>>> 
>>>> 
>>>> Here is some information on the client and what I’m doing to reproduce
>>>> the issue. I have tried krb5, and krb5p with the same results.
>>>> Removing the requirement for krb5 in the NFS server and mounting with
>>>> sec=none, I don’t seem to hit the issue.
>>>> 
>>>> 
>>>> 
>>>> $uname -a
>>>> 
>>>> 5.0.0-27-generic #28~18.04.1-Ubuntu SMP Thu Aug 22 03:00:32 UTC 2019
>>>> x86_64 x86_64 x86_64 GNU/Linux
>>>> 
>>>> 
>>>> 
>>>> $mount
>>>> 
>>>> nfs-server.example.com:/ds1 on /data type nfs4
>>>> (rw,relatime,vers=4.1,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5p,clientaddr=10.75.40.254,local_lock=none,addr=10.75.37.2)
>>>> 
>>>> 
>>>> 
>>>> $ dd if=/dev/zero of=/data/test.img count=1000 bs=1000
>>>> 
>>>> 1000+0 records in
>>>> 
>>>> 1000+0 records out
>>>> 
>>>> 1000000 bytes (1.0 MB, 977 KiB) copied, 0.00613671 s, 163 MB/s
>>>> 
>>>> $ dd if=/dev/zero of=/data/test.img bs=1000M count=6
>>>> 
>>>> ---- HUNG ----
>>>> 
>>>> 
>>>> 
>>>> After it hangs it will NEVER return. The only way I've been able to
>>>> get the client to return is to go into the U300 Control panel and
>>>> change the "SP Owner:" from SPA to SPB (effectively restarting the NFS
>>>> server). Once that happens the client returns.
>>>> 
>>>> 
>>>> 
>>>> If I disable Kerberos on the NFS Share I have no problems writing
>>>> larger files it seems.
>>>> 
>>>> 
>>>> 
>>>> I did some straces of the dd and this is what I saw.
>>>> 
>>>> 
>>>> 
>>>> This was a successful write….
>>>> 
>>>> 
>>>> 
>>>> $ strace dd if=/dev/zero of=/data/test3.img bs=100M count=1
>>>> 
>>>> execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test3.img",
>>>> "bs=100M", "count=1"], 0x7fff8c03c7f0 /* 21 vars */) = 0
>>>> 
>>>> brk(NULL)                               = 0x559b8b39a000
>>>> 
>>>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>>>> 
>>>> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
>>>> 
>>>> fstat(3, {st_mode=S_IFREG|0644, st_size=93482, ...}) = 0
>>>> 
>>>> mmap(NULL, 93482, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f62b6180000
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
>>>> 
>>>> read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
>>>> 832) = 832
>>>> 
>>>> fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
>>>> 
>>>> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>>>> 0) = 0x7f62b617e000
>>>> 
>>>> mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>>>> 0) = 0x7f62b5b7f000
>>>> 
>>>> mprotect(0x7f62b5d66000, 2097152, PROT_NONE) = 0
>>>> 
>>>> mmap(0x7f62b5f66000, 24576, PROT_READ|PROT_WRITE,
>>>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f62b5f66000
>>>> 
>>>> mmap(0x7f62b5f6c000, 15072, PROT_READ|PROT_WRITE,
>>>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f62b5f6c000
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> arch_prctl(ARCH_SET_FS, 0x7f62b617f540) = 0
>>>> 
>>>> mprotect(0x7f62b5f66000, 16384, PROT_READ) = 0
>>>> 
>>>> mprotect(0x559b8978b000, 4096, PROT_READ) = 0
>>>> 
>>>> mprotect(0x7f62b6197000, 4096, PROT_READ) = 0
>>>> 
>>>> munmap(0x7f62b6180000, 93482)           = 0
>>>> 
>>>> rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
>>>> 
>>>> rt_sigaction(SIGUSR1, {sa_handler=0x559b8957e0e0, sa_mask=[INT USR1],
>>>> sa_flags=SA_RESTORER, sa_restorer=0x7f62b5bbdf20}, NULL, 8) = 0
>>>> 
>>>> rt_sigaction(SIGINT, {sa_handler=0x559b8957e0d0, sa_mask=[INT USR1],
>>>> sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
>>>> sa_restorer=0x7f62b5bbdf20}, NULL, 8) = 0
>>>> 
>>>> brk(NULL)                               = 0x559b8b39a000
>>>> 
>>>> brk(0x559b8b3bb000)                     = 0x559b8b3bb000
>>>> 
>>>> openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
>>>> 
>>>> fstat(3, {st_mode=S_IFREG|0644, st_size=4326016, ...}) = 0
>>>> 
>>>> mmap(NULL, 4326016, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f62b575e000
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
>>>> 
>>>> dup2(3, 0)                              = 0
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> lseek(0, 0, SEEK_CUR)                   = 0
>>>> 
>>>> openat(AT_FDCWD, "/data/test3.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
>>>> 
>>>> dup2(3, 1)                              = 1
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> mmap(NULL, 104869888, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
>>>> -1, 0) = 0x7f62af35b000
>>>> 
>>>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 104857600) = 104857600
>>>> 
>>>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 104857600) = 104857600
>>>> 
>>>> close(0)                                = 0
>>>> 
>>>> close(1)                                = 0
>>>> 
>>>> openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
>>>> 
>>>> fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
>>>> 
>>>> read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
>>>> 
>>>> read(0, "", 4096)                       = 0
>>>> 
>>>> close(0)                                = 0
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
>>>> -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
>>>> -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
>>>> O_RDONLY) = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
>>>> ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
>>>> O_RDONLY) = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
>>>> O_RDONLY) = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
>>>> O_RDONLY) = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
>>>> O_RDONLY) = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
>>>> = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
>>>> O_RDONLY) = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
>>>> O_RDONLY) = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD,
>>>> "/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
>>>> 0
>>>> 
>>>> fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
>>>> 
>>>> mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f62b6196000
>>>> 
>>>> close(0)                                = 0
>>>> 
>>>> write(2, "1+0 records in\n1+0 records out\n", 311+0 records in
>>>> 
>>>> 1+0 records out
>>>> 
>>>> ) = 31
>>>> 
>>>> write(2, "104857600 bytes (105 MB, 100 MiB"..., 61104857600 bytes (105
>>>> MB, 100 MiB) copied, 1.01552 s, 103 MB/s) = 61
>>>> 
>>>> write(2, "\n", 1
>>>> 
>>>> )                       = 1
>>>> 
>>>> close(2)                                = 0
>>>> 
>>>> exit_group(0)                           = ?
>>>> 
>>>> +++ exited with 0 +++
>>>> 
>>>> 
>>>> 
>>>> This one was unsuccessful write and hung until I restarted the NFS server.
>>>> 
>>>> 
>>>> 
>>>> strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=6
>>>> 
>>>> execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
>>>> "bs=1000M", "count=6"], 0x7ffc8ee7e8b8 /* 30 vars */) = 0
>>>> 
>>>> brk(NULL)                               = 0x5648bd26a000
>>>> 
>>>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>>>> 
>>>> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
>>>> 
>>>> fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
>>>> 
>>>> mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4f8dda1000
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
>>>> 
>>>> openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
>>>> 
>>>> read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
>>>> 832) = 832
>>>> 
>>>> fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
>>>> 
>>>> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
>>>> 0) = 0x7f4f8dd9f000
>>>> 
>>>> mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
>>>> 0) = 0x7f4f8d7a8000
>>>> 
>>>> mprotect(0x7f4f8d98f000, 2097152, PROT_NONE) = 0
>>>> 
>>>> mmap(0x7f4f8db8f000, 24576, PROT_READ|PROT_WRITE,
>>>> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f4f8db8f000
>>>> 
>>>> mmap(0x7f4f8db95000, 15072, PROT_READ|PROT_WRITE,
>>>> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f4f8db95000
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> arch_prctl(ARCH_SET_FS, 0x7f4f8dda0540) = 0
>>>> 
>>>> mprotect(0x7f4f8db8f000, 16384, PROT_READ) = 0
>>>> 
>>>> mprotect(0x5648bb739000, 4096, PROT_READ) = 0
>>>> 
>>>> mprotect(0x7f4f8ddc0000, 4096, PROT_READ) = 0
>>>> 
>>>> munmap(0x7f4f8dda1000, 125550)          = 0
>>>> 
>>>> rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
>>>> 
>>>> rt_sigaction(SIGUSR1, {sa_handler=0x5648bb52c0e0, sa_mask=[INT USR1],
>>>> sa_flags=SA_RESTORER, sa_restorer=0x7f4f8d7e6f20}, NULL, 8) = 0
>>>> 
>>>> rt_sigaction(SIGINT, {sa_handler=0x5648bb52c0d0, sa_mask=[INT USR1],
>>>> sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
>>>> sa_restorer=0x7f4f8d7e6f20}, NULL, 8) = 0
>>>> 
>>>> brk(NULL)                               = 0x5648bd26a000
>>>> 
>>>> brk(0x5648bd28b000)                     = 0x5648bd28b000
>>>> 
>>>> openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
>>>> 
>>>> fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
>>>> 
>>>> mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4f8cc97000
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
>>>> 
>>>> dup2(3, 0)                              = 0
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> lseek(0, 0, SEEK_CUR)                   = 0
>>>> 
>>>> openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
>>>> 
>>>> dup2(3, 1)                              = 1
>>>> 
>>>> close(3)                                = 0
>>>> 
>>>> mmap(NULL, 1048588288, PROT_READ|PROT_WRITE,
>>>> MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4f4e494000
>>>> 
>>>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
>>>> 1048576000) = 1048576000
>>>> 
>>>> close(0)                                = 0
>>>> 
>>>> close(1
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> I did some packet tracing and on the smaller writes, I would see a
>>>> bunch of writes and replies to those writes, the client would COMMIT
>>>> and then NFS server would reply with an ack COMMIT, client would then
>>>> issue a CLOSE, and server would respond with a CLOSE. However, on
>>>> larger writes where it would hang it would do…client would do a bunch
>>>> of writes packets, NFS server would respond to the write packets,
>>>> client would issue a COMMIT command, server would respond with a
>>>> COMMIT, and then nothing else would happen. No CLOSE would seemingly
>>>> be sent from the client, so I don’t know if the client was waiting on
>>>> the server to send back some type of message saying that the system
>>>> could issue a CLOSE or the client was never sending a CLOSE.
>>>> 
>>>> 
>>>> 
>>>> Once it is in the locked state, if I restart the NFS server as I
>>>> mentioned above the close(1…will continue and finish the write and
>>>> exit normally.
>>>> 
>>>> 
>>>> 
>>>> I did a kernel Stack Traceback on the NFS client (the light weight
>>>> version of just printing out /proc/*/wchan) while the dd command was
>>>> stuck in the “close(1” and the process for the dd command just says.
>>>> 
>>>> 
>>>> 
>>>> Process /proc/32161/wchan
>>>> 
>>>> ep_poll
>>>> 
>>>> 
>>>> 
>>>> I also enabled the NFS debugging and while its stuck it just keep
>>>> repeating the bottom section.
>>>> 
>>>> 
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270750] NFS:       commit
>>>> (0:52/9439 4096@4609744896) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270751] NFS:       commit
>>>> (0:52/9439 4096@4609748992) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270754] NFS:       commit
>>>> (0:52/9439 4096@4609753088) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270757] NFS:       commit
>>>> (0:52/9439 4096@4609757184) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270759] NFS:       commit
>>>> (0:52/9439 4096@4609761280) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270761] NFS:       commit
>>>> (0:52/9439 4096@4609765376) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270763] NFS:       commit
>>>> (0:52/9439 4096@4609769472) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270767] NFS:       commit
>>>> (0:52/9439 4096@4609773568) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270769] NFS:       commit
>>>> (0:52/9439 4096@4609777664) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270772] NFS:       commit
>>>> (0:52/9439 4096@4609781760) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270773] NFS:       commit
>>>> (0:52/9439 4096@4609785856) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270775] NFS:       commit
>>>> (0:52/9439 4096@4609789952) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270777] NFS:       commit
>>>> (0:52/9439 4096@4609794048) OK
>>>> 
>>>> Sep 19 06:25:19 examplehost kernel: [772614.270781] NFS:       commit
>>>> (0:52/9439 4096@4609798144) OK
>>>> 
>>>> Sep 19 06:25:31 examplehost kernel: [772626.175927] <--
>>>> nfs41_proc_async_sequence status=0
>>>> 
>>>> Sep 19 06:25:31 examplehost kernel: [772626.176018] encode_sequence:
>>>> sessionid=61:1568410703:305419896:61 seqid=2907 slotid=0 max_slotid=35
>>>> cache_this=0
>>>> 
>>>> Sep 19 06:25:31 examplehost kernel: [772626.176572]
>>>> nfs41_sequence_process: Error 0 free the slot
>>>> 
>>>> Sep 19 06:25:31 examplehost kernel: [772626.176576]
>>>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>>>> 
>>>> Sep 19 06:25:31 examplehost kernel: [772626.176577] <-- nfs41_sequence_call_done
>>>> 
>>>> Sep 19 06:25:43 examplehost kernel: [772638.207976] <--
>>>> nfs41_proc_async_sequence status=0
>>>> 
>>>> Sep 19 06:25:43 examplehost kernel: [772638.208074] encode_sequence:
>>>> sessionid=61:1568410703:305419896:61 seqid=2908 slotid=0 max_slotid=35
>>>> cache_this=0
>>>> 
>>>> Sep 19 06:25:43 examplehost kernel: [772638.208642]
>>>> nfs41_sequence_process: Error 0 free the slot
>>>> 
>>>> Sep 19 06:25:43 examplehost kernel: [772638.208646]
>>>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>>>> 
>>>> Sep 19 06:25:43 examplehost kernel: [772638.208648] <-- nfs41_sequence_call_done
>>>> 
>>>> Sep 19 06:25:55 examplehost kernel: [772650.240046] <--
>>>> nfs41_proc_async_sequence status=0
>>>> 
>>>> Sep 19 06:25:55 examplehost kernel: [772650.240129] encode_sequence:
>>>> sessionid=61:1568410703:305419896:61 seqid=2909 slotid=0 max_slotid=35
>>>> cache_this=0
>>>> 
>>>> Sep 19 06:25:55 examplehost kernel: [772650.240904]
>>>> nfs41_sequence_process: Error 0 free the slot
>>>> 
>>>> Sep 19 06:25:55 examplehost kernel: [772650.240908]
>>>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>>>> 
>>>> Sep 19 06:25:55 examplehost kernel: [772650.240909] <-- nfs41_sequence_call_done
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> On a small file that actually completes it looks like this…
>>>> 
>>>> 
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532059] NFS:       commit
>>>> (0:52/9439 4096@7409315840) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532061] NFS:       commit
>>>> (0:52/9439 4096@7409319936) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532064] NFS:       commit
>>>> (0:52/9439 4096@7409324032) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532066] NFS:       commit
>>>> (0:52/9439 4096@7409328128) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532069] NFS:       commit
>>>> (0:52/9439 4096@7409332224) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532071] NFS:       commit
>>>> (0:52/9439 4096@7409336320) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532073] NFS:       commit
>>>> (0:52/9439 4096@7409340416) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532076] NFS:       commit
>>>> (0:52/9439 4096@7409344512) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532078] NFS:       commit
>>>> (0:52/9439 4096@7409348608) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532081] NFS:       commit
>>>> (0:52/9439 4096@7409352704) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532083] NFS:       commit
>>>> (0:52/9439 4096@7409356800) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532086] NFS:       commit
>>>> (0:52/9439 4096@7409360896) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532088] NFS:       commit
>>>> (0:52/9439 4096@7409364992) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532090] NFS:       commit
>>>> (0:52/9439 4096@7409369088) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532093] NFS:       commit
>>>> (0:52/9439 4096@7409373184) OK
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532171] NFS: release(/test.img)
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532193] nfs4_close_prepare: begin!
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532197] nfs4_close_prepare: done!
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532235] encode_sequence:
>>>> sessionid=61:1568410703:305419896:61 seqid=6 slotid=0 max_slotid=0
>>>> cache_this=1
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532525] nfs4_close_done: begin!
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532528]
>>>> nfs41_sequence_process: Error 0 free the slot
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532531] nfs4_close_done:
>>>> done, ret = 0!
>>>> 
>>>> Sep 19 06:13:29 examplehost kernel: [771904.532555] NFS:
>>>> dentry_delete(/test.img, 48084c)
>>>> 
>>>> Sep 19 06:13:41 examplehost kernel: [771916.540491] <--
>>>> nfs41_proc_async_sequence status=0
>>>> 
>>>> Sep 19 06:13:41 examplehost kernel: [771916.540586] encode_sequence:
>>>> sessionid=61:1568410703:305419896:61 seqid=7 slotid=0 max_slotid=0
>>>> cache_this=0
>>>> 
>>>> Sep 19 06:13:41 examplehost kernel: [771916.541182]
>>>> nfs41_sequence_process: Error 0 free the slot
>>>> 
>>>> Sep 19 06:13:41 examplehost kernel: [771916.541186]
>>>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>>>> 
>>>> Sep 19 06:13:41 examplehost kernel: [771916.541187] <-- nfs41_sequence_call_done
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.572599] <--
>>>> nfs41_proc_async_sequence status=0
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.572675] encode_sequence:
>>>> sessionid=61:1568410703:305419896:61 seqid=8 slotid=0 max_slotid=0
>>>> cache_this=0
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.572895] encode_sequence:
>>>> sessionid=61:1568410703:305419896:61 seqid=2 slotid=1 max_slotid=1
>>>> cache_this=1
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573163]
>>>> nfs41_sequence_process: Error 0 free the slot
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573166]
>>>> nfs41_sequence_call_done rpc_cred 000000004b01718a
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573167] <-- nfs41_sequence_call_done
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573236] decode_attr_type: type=00
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573238]
>>>> decode_attr_change: change attribute=6738121685800950864
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573240] decode_attr_size:
>>>> file size=8388608000
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573242] decode_attr_fsid:
>>>> fsid=(0x0/0x0)
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573243] decode_attr_fileid: fileid=0
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573245]
>>>> decode_attr_fs_locations: fs_locations done, error = 0
>>>> 
>>>> Sep 19 06:13:53 examplehost kernel: [771928.573246] decode_attr_mode:
>>>> file mode=00
>>>> 
>>>> 
>>>> 
>>>> As you can see the NFS: release(/test.img) is immediately after all of
>>>> the writes on the successful version. In the version that gets stuck
>>>> it never responds with that “release”.
>>>> 
>>>> 
>>>> 
>>>> It’s hard for me to do any debugging on the NFS Server sinces its more
>>>> of a “managed” box (e.g I don’t have root and only have access to
>>>> certain debugging utilities). I do have a ticket open with Dell and
>>>> their engineering team is looking at this but I’m trying anything I
>>>> can do to figure this out as soon as I can.
>>>> 
>>>> 
>>>> 
>>>> 
>>>> Any help on this matter would be appreciated.
>>> 
> 

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-18 23:36 NFSv4 client locks up on larger writes with Kerberos enabled Kevin Vasko
       [not found] ` <E172CA50-EC89-4072-9C1D-1B825DC3FE8B@lysator.liu.se>
@ 2019-09-25 16:48 ` bfields
  2019-09-25 17:06   ` Chuck Lever
  1 sibling, 1 reply; 16+ messages in thread
From: bfields @ 2019-09-25 16:48 UTC (permalink / raw)
  To: Kevin Vasko; +Cc: linux-nfs

On Wed, Sep 18, 2019 at 06:36:13PM -0500, Kevin Vasko wrote:
> We have a new Dell EMC Unity 300 acting as NAS Server that is
> presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
> but issue is also present on CentOS 7.6 systems. We have been
> struggling with this issue for over a week now and not sure how to
> resolve it.
> 
> 
> 
> We are having trouble with NFS Clients completing their writes to the
> Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
> Share. I created the NFS Share on the U300, associated it with our
> FreeIPA (Kerberos/LDAP server) and everything shows successful.

Troubleshooting ideas off the top of my head:

It might be worth trying some other client versions if it's not hard.

It'd be interesting to know what's happening on the network....
Unfortunately big krb5p writes won't be fun to try to capture and
examine.  Maybe some network or rpc-level statistics would help show if
there are an unusual number of retries or failures.

--b.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-25 16:48 ` bfields
@ 2019-09-25 17:06   ` Chuck Lever
  2019-09-25 18:44     ` Kevin Vasko
  0 siblings, 1 reply; 16+ messages in thread
From: Chuck Lever @ 2019-09-25 17:06 UTC (permalink / raw)
  To: Bruce Fields; +Cc: Kevin Vasko, Linux NFS Mailing List



> On Sep 25, 2019, at 9:48 AM, bfields@fieldses.org wrote:
> 
> On Wed, Sep 18, 2019 at 06:36:13PM -0500, Kevin Vasko wrote:
>> We have a new Dell EMC Unity 300 acting as NAS Server that is
>> presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
>> but issue is also present on CentOS 7.6 systems. We have been
>> struggling with this issue for over a week now and not sure how to
>> resolve it.
>> 
>> 
>> 
>> We are having trouble with NFS Clients completing their writes to the
>> Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
>> Share. I created the NFS Share on the U300, associated it with our
>> FreeIPA (Kerberos/LDAP server) and everything shows successful.
> 
> Troubleshooting ideas off the top of my head:
> 
> It might be worth trying some other client versions if it's not hard.
> 
> It'd be interesting to know what's happening on the network....
> Unfortunately big krb5p writes won't be fun to try to capture and
> examine.

Wireshark is supposed to have a mechanism for giving it the keys
so that captured GSS data can be decrypted. I've never gotten it
to work, but I didn't try hard. Should be appropriately documented.


> Maybe some network or rpc-level statistics would help show if
> there are an unusual number of retries or failures.


--
Chuck Lever




^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-25 17:06   ` Chuck Lever
@ 2019-09-25 18:44     ` Kevin Vasko
  2019-09-25 18:49       ` Chuck Lever
  2019-09-26  7:30       ` Daniel Kobras
  0 siblings, 2 replies; 16+ messages in thread
From: Kevin Vasko @ 2019-09-25 18:44 UTC (permalink / raw)
  To: Chuck Lever; +Cc: Bruce Fields, Linux NFS Mailing List

Appreciate the information. I have tried different clients. The Centos
and Ubuntu clients exhibit the same issue. I also did packet tracing.
On small files the client will go through its "WRITE..." packets...
and then will issue COMMIT and then do the CLOSE. On larger files it
will do all of its WRITE... packets and then will issue COMMIT and
then it will never do a CLOSE. I'm assuming whats happening is the
client is waiting for the NFS server to authenticate with the Kerberos
server to make sure the write is okay, however I assume it never does.
I would like to try and figure out how to see that "authentication"
packet to kerberos from the server (if there is one).

Just for giggles, I just tried it with NFSv3 and there is a slight
change and gives a little more information (albeit, what I kind of
already assumed). Mounted the shared with krb5p, and vers=3.

 I write a file with
strace -f dd if=/dev/zero of=/data/test.img bs=10M count=1

This is successful.  No issues. Just like NFSv4

Then I change nothing but the size of the file being written (just
like with NFSv4)…however with NFSv3 it will halt for ~1 minute and
then spit out a permission denied even though I just wrote out the
SAME exact file in the SAME exact location (literally overwriting the
file) a few seconds prior. The only difference in NFSv3 and NFSv4 is
that NFSv3 fails with a permission issue, whereas NFSv4 never returns.

strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=1

This command with NFSv3, takes ~1min and will return file permissions
error (even though it just wrote it and can run the above command
again and it will finish with no errors).

This makes sense in that my initial suspicion is that the Dell Unity
300 isn’t authenticating properly with larger writes (for whatever
reason) with Kerberos. This is also why I don’t see the problem when I
disable Kerberos on the Unity 300 system.

When should the NFS server be sending a packet to the Kerberos server
to validate the write? Or should it be? I did do packet capture on the
Unity box but I don’t see anything really useful regarding Kerberos
authentication. What should I be looking for in the packet traces to
look for the authentication packets?

 Debugging commands:

$mount

...snip…

10.75.37.2:/ds1 on /data type nfs
(rw,relatime,vers=3,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5p,mountaddr=10.75.37.2,mountvers=3,mountport=1234,mountproto=udp,local_lock=none,addr=10.75.37.2)



$ time dd if=/dev/zero of=/data/test.img bs=10M count=1
1+0 records in
1+0 records out
10485760 bytes (10 MB, 10 MiB) copied, 0.112561 s, 93.2 MB/s
real    0m0.188s
user    0m0.000s
sys     0m0.087s

$ time dd if=/dev/zero of=/data/test.img bs=1000M count=1
dd: closing output file '/data/test.img': Permission denied
real    1m9.093s
user    0m0.000s
sys     0m1.124s

$ strace -f dd if=/dev/zero of=/data/test.img bs=10M count=1
execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
"bs=10M", "count=1"], 0x7ffec9914328 /* 30 vars */) = 0
brk(NULL)                               = 0x5595514e6000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5e4e5d2000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f5e4e5d0000
mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x7f5e4dfd9000
mprotect(0x7f5e4e1c0000, 2097152, PROT_NONE) = 0
mmap(0x7f5e4e3c0000, 24576, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f5e4e3c0000
mmap(0x7f5e4e3c6000, 15072, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f5e4e3c6000
close(3)                                = 0
arch_prctl(ARCH_SET_FS, 0x7f5e4e5d1540) = 0
mprotect(0x7f5e4e3c0000, 16384, PROT_READ) = 0
mprotect(0x55954fd03000, 4096, PROT_READ) = 0
mprotect(0x7f5e4e5f1000, 4096, PROT_READ) = 0
munmap(0x7f5e4e5d2000, 125550)          = 0
rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGUSR1, {sa_handler=0x55954faf60e0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER, sa_restorer=0x7f5e4e017f20}, NULL, 8) = 0
rt_sigaction(SIGINT, {sa_handler=0x55954faf60d0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
a_restorer=0x7f5e4e017f20}, NULL, 8) = 0
brk(NULL)                               = 0x5595514e6000
brk(0x559551507000)                     = 0x559551507000
openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5e4d4c8000
close(3)                                = 0
openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
dup2(3, 0)                              = 0
close(3)                                = 0
lseek(0, 0, SEEK_CUR)                   = 0
openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
dup2(3, 1)                              = 1
close(3)                                = 0
mmap(NULL, 10498048, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0x7f5e4cac5000
read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
10485760) = 10485760
write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
10485760) = 10485760
close(0)                                = 0
close(1)                                = 0
openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
read(0, "", 4096)                       = 0
close(0)                                = 0
openat(AT_FDCWD,
"/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
= -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
0
fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f5e4e5f0000
close(0)                                = 0
write(2, "1+0 records in\n1+0 records out\n", 311+0 records in
1+0 records out
) = 31
write(2, "10485760 bytes (10 MB, 10 MiB) c"..., 6010485760 bytes (10
MB, 10 MiB) copied, 0.105735 s, 99.2 MB/s) = 60
write(2, "\n", 1
)                       = 1
close(2)                                = 0
exit_group(0)                           = ?
+++ exited with 0 +++



$ strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=1
execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
"bs=1000M", "count=1"], 0x7fff46397c58 /* 30 vars */) = 0
brk(NULL)                               = 0x55a768f09000
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f604f357000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f604f355000
mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x7f604ed5e000
mprotect(0x7f604ef45000, 2097152, PROT_NONE) = 0
mmap(0x7f604f145000, 24576, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f604f145000
mmap(0x7f604f14b000, 15072, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f604f14b000
close(3)                                = 0
arch_prctl(ARCH_SET_FS, 0x7f604f356540) = 0
mprotect(0x7f604f145000, 16384, PROT_READ) = 0
mprotect(0x55a767990000, 4096, PROT_READ) = 0
mprotect(0x7f604f376000, 4096, PROT_READ) = 0
munmap(0x7f604f357000, 125550)          = 0
rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGUSR1, {sa_handler=0x55a7677830e0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER, sa_restorer=0x7f604ed9cf20}, NULL, 8) = 0
rt_sigaction(SIGINT, {sa_handler=0x55a7677830d0, sa_mask=[INT USR1],
sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
a_restorer=0x7f604ed9cf20}, NULL, 8) = 0
brk(NULL)                               = 0x55a768f09000
brk(0x55a768f2a000)                     = 0x55a768f2a000
openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f604e24d000
close(3)                                = 0
openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
dup2(3, 0)                              = 0
close(3)                                = 0
lseek(0, 0, SEEK_CUR)                   = 0
openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
dup2(3, 1)                              = 1
close(3)                                = 0
mmap(NULL, 1048588288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f600fa4a000
read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000
write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
1048576000) = 1048576000
close(0)                                = 0
close(1)                                = -1 EACCES (Permission denied)
openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
read(0, "", 4096)                       = 0
close(0)                                = 0
openat(AT_FDCWD,
"/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
= -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
0
fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f604f375000
close(0)                                = 0
write(2, "dd: ", 4dd: )                     = 4
write(2, "closing output file '/data/test."..., 36closing output file
'/data/test.img') = 36
openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY)
= -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/libc.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY)
= -1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1
ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
openat(AT_FDCWD,
"/usr/share/locale-langpack/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) =
-1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale-langpack/en/LC_MESSAGES/libc.mo",
O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, ": Permission denied", 19: Permission denied)     = 19
write(2, "\n", 1
)                       = 1
close(2)                                = 0
exit_group(1)                           = ?
+++ exited with 1 +++

On Wed, Sep 25, 2019 at 12:06 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>
>
>
> > On Sep 25, 2019, at 9:48 AM, bfields@fieldses.org wrote:
> >
> > On Wed, Sep 18, 2019 at 06:36:13PM -0500, Kevin Vasko wrote:
> >> We have a new Dell EMC Unity 300 acting as NAS Server that is
> >> presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
> >> but issue is also present on CentOS 7.6 systems. We have been
> >> struggling with this issue for over a week now and not sure how to
> >> resolve it.
> >>
> >>
> >>
> >> We are having trouble with NFS Clients completing their writes to the
> >> Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
> >> Share. I created the NFS Share on the U300, associated it with our
> >> FreeIPA (Kerberos/LDAP server) and everything shows successful.
> >
> > Troubleshooting ideas off the top of my head:
> >
> > It might be worth trying some other client versions if it's not hard.
> >
> > It'd be interesting to know what's happening on the network....
> > Unfortunately big krb5p writes won't be fun to try to capture and
> > examine.
>
> Wireshark is supposed to have a mechanism for giving it the keys
> so that captured GSS data can be decrypted. I've never gotten it
> to work, but I didn't try hard. Should be appropriately documented.
>
>
> > Maybe some network or rpc-level statistics would help show if
> > there are an unusual number of retries or failures.
>
>
> --
> Chuck Lever
>
>
>

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-25 18:44     ` Kevin Vasko
@ 2019-09-25 18:49       ` Chuck Lever
  2019-09-25 19:10         ` Kevin Vasko
  2019-09-25 20:07         ` Bruce Fields
  2019-09-26  7:30       ` Daniel Kobras
  1 sibling, 2 replies; 16+ messages in thread
From: Chuck Lever @ 2019-09-25 18:49 UTC (permalink / raw)
  To: Kevin Vasko; +Cc: Bruce Fields, Linux NFS Mailing List



> On Sep 25, 2019, at 11:44 AM, Kevin Vasko <kvasko@gmail.com> wrote:
> 
> Appreciate the information. I have tried different clients. The Centos
> and Ubuntu clients exhibit the same issue. I also did packet tracing.
> On small files the client will go through its "WRITE..." packets...
> and then will issue COMMIT and then do the CLOSE. On larger files it
> will do all of its WRITE... packets and then will issue COMMIT and
> then it will never do a CLOSE. I'm assuming whats happening is the
> client is waiting for the NFS server to authenticate with the Kerberos
> server to make sure the write is okay, however I assume it never does.
> I would like to try and figure out how to see that "authentication"
> packet to kerberos from the server (if there is one).
> 
> Just for giggles, I just tried it with NFSv3 and there is a slight
> change and gives a little more information (albeit, what I kind of
> already assumed). Mounted the shared with krb5p, and vers=3.
> 
> I write a file with
> strace -f dd if=/dev/zero of=/data/test.img bs=10M count=1
> 
> This is successful.  No issues. Just like NFSv4
> 
> Then I change nothing but the size of the file being written (just
> like with NFSv4)…however with NFSv3 it will halt for ~1 minute and
> then spit out a permission denied even though I just wrote out the
> SAME exact file in the SAME exact location (literally overwriting the
> file) a few seconds prior. The only difference in NFSv3 and NFSv4 is
> that NFSv3 fails with a permission issue, whereas NFSv4 never returns.

Sounds like the NFS server is dropping the connection. With
GSS enabled, that's usually a sign that the GSS window has
overflowed.


> strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=1
> 
> This command with NFSv3, takes ~1min and will return file permissions
> error (even though it just wrote it and can run the above command
> again and it will finish with no errors).
> 
> This makes sense in that my initial suspicion is that the Dell Unity
> 300 isn’t authenticating properly with larger writes (for whatever
> reason) with Kerberos. This is also why I don’t see the problem when I
> disable Kerberos on the Unity 300 system.
> 
> When should the NFS server be sending a packet to the Kerberos server
> to validate the write? Or should it be? I did do packet capture on the
> Unity box but I don’t see anything really useful regarding Kerberos
> authentication. What should I be looking for in the packet traces to
> look for the authentication packets?
> 
> Debugging commands:
> 
> $mount
> 
> ...snip…
> 
> 10.75.37.2:/ds1 on /data type nfs
> (rw,relatime,vers=3,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5p,mountaddr=10.75.37.2,mountvers=3,mountport=1234,mountproto=udp,local_lock=none,addr=10.75.37.2)
> 
> 
> 
> $ time dd if=/dev/zero of=/data/test.img bs=10M count=1
> 1+0 records in
> 1+0 records out
> 10485760 bytes (10 MB, 10 MiB) copied, 0.112561 s, 93.2 MB/s
> real    0m0.188s
> user    0m0.000s
> sys     0m0.087s
> 
> $ time dd if=/dev/zero of=/data/test.img bs=1000M count=1
> dd: closing output file '/data/test.img': Permission denied
> real    1m9.093s
> user    0m0.000s
> sys     0m1.124s
> 
> $ strace -f dd if=/dev/zero of=/data/test.img bs=10M count=1
> execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
> "bs=10M", "count=1"], 0x7ffec9914328 /* 30 vars */) = 0
> brk(NULL)                               = 0x5595514e6000
> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
> fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
> mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5e4e5d2000
> close(3)                                = 0
> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
> read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
> 832) = 832
> fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0x7f5e4e5d0000
> mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> 0) = 0x7f5e4dfd9000
> mprotect(0x7f5e4e1c0000, 2097152, PROT_NONE) = 0
> mmap(0x7f5e4e3c0000, 24576, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f5e4e3c0000
> mmap(0x7f5e4e3c6000, 15072, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f5e4e3c6000
> close(3)                                = 0
> arch_prctl(ARCH_SET_FS, 0x7f5e4e5d1540) = 0
> mprotect(0x7f5e4e3c0000, 16384, PROT_READ) = 0
> mprotect(0x55954fd03000, 4096, PROT_READ) = 0
> mprotect(0x7f5e4e5f1000, 4096, PROT_READ) = 0
> munmap(0x7f5e4e5d2000, 125550)          = 0
> rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
> rt_sigaction(SIGUSR1, {sa_handler=0x55954faf60e0, sa_mask=[INT USR1],
> sa_flags=SA_RESTORER, sa_restorer=0x7f5e4e017f20}, NULL, 8) = 0
> rt_sigaction(SIGINT, {sa_handler=0x55954faf60d0, sa_mask=[INT USR1],
> sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
> a_restorer=0x7f5e4e017f20}, NULL, 8) = 0
> brk(NULL)                               = 0x5595514e6000
> brk(0x559551507000)                     = 0x559551507000
> openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
> fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
> mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5e4d4c8000
> close(3)                                = 0
> openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
> dup2(3, 0)                              = 0
> close(3)                                = 0
> lseek(0, 0, SEEK_CUR)                   = 0
> openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
> dup2(3, 1)                              = 1
> close(3)                                = 0
> mmap(NULL, 10498048, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
> -1, 0) = 0x7f5e4cac5000
> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> 10485760) = 10485760
> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> 10485760) = 10485760
> close(0)                                = 0
> close(1)                                = 0
> openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
> fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
> read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
> read(0, "", 4096)                       = 0
> close(0)                                = 0
> openat(AT_FDCWD,
> "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
> ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
> = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> 0
> fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
> mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f5e4e5f0000
> close(0)                                = 0
> write(2, "1+0 records in\n1+0 records out\n", 311+0 records in
> 1+0 records out
> ) = 31
> write(2, "10485760 bytes (10 MB, 10 MiB) c"..., 6010485760 bytes (10
> MB, 10 MiB) copied, 0.105735 s, 99.2 MB/s) = 60
> write(2, "\n", 1
> )                       = 1
> close(2)                                = 0
> exit_group(0)                           = ?
> +++ exited with 0 +++
> 
> 
> 
> $ strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=1
> execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
> "bs=1000M", "count=1"], 0x7fff46397c58 /* 30 vars */) = 0
> brk(NULL)                               = 0x55a768f09000
> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
> fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
> mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f604f357000
> close(3)                                = 0
> access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
> read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
> 832) = 832
> fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
> mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0x7f604f355000
> mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> 0) = 0x7f604ed5e000
> mprotect(0x7f604ef45000, 2097152, PROT_NONE) = 0
> mmap(0x7f604f145000, 24576, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f604f145000
> mmap(0x7f604f14b000, 15072, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f604f14b000
> close(3)                                = 0
> arch_prctl(ARCH_SET_FS, 0x7f604f356540) = 0
> mprotect(0x7f604f145000, 16384, PROT_READ) = 0
> mprotect(0x55a767990000, 4096, PROT_READ) = 0
> mprotect(0x7f604f376000, 4096, PROT_READ) = 0
> munmap(0x7f604f357000, 125550)          = 0
> rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
> rt_sigaction(SIGUSR1, {sa_handler=0x55a7677830e0, sa_mask=[INT USR1],
> sa_flags=SA_RESTORER, sa_restorer=0x7f604ed9cf20}, NULL, 8) = 0
> rt_sigaction(SIGINT, {sa_handler=0x55a7677830d0, sa_mask=[INT USR1],
> sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
> a_restorer=0x7f604ed9cf20}, NULL, 8) = 0
> brk(NULL)                               = 0x55a768f09000
> brk(0x55a768f2a000)                     = 0x55a768f2a000
> openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
> fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
> mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f604e24d000
> close(3)                                = 0
> openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
> dup2(3, 0)                              = 0
> close(3)                                = 0
> lseek(0, 0, SEEK_CUR)                   = 0
> openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
> dup2(3, 1)                              = 1
> close(3)                                = 0
> mmap(NULL, 1048588288, PROT_READ|PROT_WRITE,
> MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f600fa4a000
> read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> 1048576000) = 1048576000
> write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> 1048576000) = 1048576000
> close(0)                                = 0
> close(1)                                = -1 EACCES (Permission denied)
> openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
> fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
> read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
> read(0, "", 4096)                       = 0
> close(0)                                = 0
> openat(AT_FDCWD,
> "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
> ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
> = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> 0
> fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
> mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f604f375000
> close(0)                                = 0
> write(2, "dd: ", 4dd: )                     = 4
> write(2, "closing output file '/data/test."..., 36closing output file
> '/data/test.img') = 36
> openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY)
> = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/libc.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY)
> = -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1
> ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) =
> -1 ENOENT (No such file or directory)
> openat(AT_FDCWD,
> "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) =
> -1 ENOENT (No such file or directory)
> openat(AT_FDCWD, "/usr/share/locale-langpack/en/LC_MESSAGES/libc.mo",
> O_RDONLY) = -1 ENOENT (No such file or directory)
> write(2, ": Permission denied", 19: Permission denied)     = 19
> write(2, "\n", 1
> )                       = 1
> close(2)                                = 0
> exit_group(1)                           = ?
> +++ exited with 1 +++
> 
> On Wed, Sep 25, 2019 at 12:06 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>> 
>> 
>> 
>>> On Sep 25, 2019, at 9:48 AM, bfields@fieldses.org wrote:
>>> 
>>> On Wed, Sep 18, 2019 at 06:36:13PM -0500, Kevin Vasko wrote:
>>>> We have a new Dell EMC Unity 300 acting as NAS Server that is
>>>> presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
>>>> but issue is also present on CentOS 7.6 systems. We have been
>>>> struggling with this issue for over a week now and not sure how to
>>>> resolve it.
>>>> 
>>>> 
>>>> 
>>>> We are having trouble with NFS Clients completing their writes to the
>>>> Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
>>>> Share. I created the NFS Share on the U300, associated it with our
>>>> FreeIPA (Kerberos/LDAP server) and everything shows successful.
>>> 
>>> Troubleshooting ideas off the top of my head:
>>> 
>>> It might be worth trying some other client versions if it's not hard.
>>> 
>>> It'd be interesting to know what's happening on the network....
>>> Unfortunately big krb5p writes won't be fun to try to capture and
>>> examine.
>> 
>> Wireshark is supposed to have a mechanism for giving it the keys
>> so that captured GSS data can be decrypted. I've never gotten it
>> to work, but I didn't try hard. Should be appropriately documented.
>> 
>> 
>>> Maybe some network or rpc-level statistics would help show if
>>> there are an unusual number of retries or failures.
>> 
>> 
>> --
>> Chuck Lever
>> 
>> 
>> 

--
Chuck Lever




^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-25 18:49       ` Chuck Lever
@ 2019-09-25 19:10         ` Kevin Vasko
  2019-09-25 20:07         ` Bruce Fields
  1 sibling, 0 replies; 16+ messages in thread
From: Kevin Vasko @ 2019-09-25 19:10 UTC (permalink / raw)
  To: Chuck Lever, Linux NFS Mailing List

Forgive my ignorance but I assume you mean GSS (Generic Security
Services) of which Kerberos is an implementation of? So effectively in
my environment with Kerberos being enabled, thats usually a sign that
the GSS window has overflowed? I assume that would be the same meaning
for my context?

"Sounds like the NFS server is dropping the connection."
This seems certainly likely that this could be the issue. Is there a
way of proving that the GSS window is overflowing via the packets? If
I could get to the rpc-gssd service on the NFS server would that show
me what I need to know? Or would there be some other service that
would help narrow it down?

Thanks again,

-Kevin

On Wed, Sep 25, 2019 at 1:49 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>
>
>
> > On Sep 25, 2019, at 11:44 AM, Kevin Vasko <kvasko@gmail.com> wrote:
> >
> > Appreciate the information. I have tried different clients. The Centos
> > and Ubuntu clients exhibit the same issue. I also did packet tracing.
> > On small files the client will go through its "WRITE..." packets...
> > and then will issue COMMIT and then do the CLOSE. On larger files it
> > will do all of its WRITE... packets and then will issue COMMIT and
> > then it will never do a CLOSE. I'm assuming whats happening is the
> > client is waiting for the NFS server to authenticate with the Kerberos
> > server to make sure the write is okay, however I assume it never does.
> > I would like to try and figure out how to see that "authentication"
> > packet to kerberos from the server (if there is one).
> >
> > Just for giggles, I just tried it with NFSv3 and there is a slight
> > change and gives a little more information (albeit, what I kind of
> > already assumed). Mounted the shared with krb5p, and vers=3.
> >
> > I write a file with
> > strace -f dd if=/dev/zero of=/data/test.img bs=10M count=1
> >
> > This is successful.  No issues. Just like NFSv4
> >
> > Then I change nothing but the size of the file being written (just
> > like with NFSv4)…however with NFSv3 it will halt for ~1 minute and
> > then spit out a permission denied even though I just wrote out the
> > SAME exact file in the SAME exact location (literally overwriting the
> > file) a few seconds prior. The only difference in NFSv3 and NFSv4 is
> > that NFSv3 fails with a permission issue, whereas NFSv4 never returns.
>
> Sounds like the NFS server is dropping the connection. With
> GSS enabled, that's usually a sign that the GSS window has
> overflowed.
>
>
> > strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=1
> >
> > This command with NFSv3, takes ~1min and will return file permissions
> > error (even though it just wrote it and can run the above command
> > again and it will finish with no errors).
> >
> > This makes sense in that my initial suspicion is that the Dell Unity
> > 300 isn’t authenticating properly with larger writes (for whatever
> > reason) with Kerberos. This is also why I don’t see the problem when I
> > disable Kerberos on the Unity 300 system.
> >
> > When should the NFS server be sending a packet to the Kerberos server
> > to validate the write? Or should it be? I did do packet capture on the
> > Unity box but I don’t see anything really useful regarding Kerberos
> > authentication. What should I be looking for in the packet traces to
> > look for the authentication packets?
> >
> > Debugging commands:
> >
> > $mount
> >
> > ...snip…
> >
> > 10.75.37.2:/ds1 on /data type nfs
> > (rw,relatime,vers=3,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=krb5p,mountaddr=10.75.37.2,mountvers=3,mountport=1234,mountproto=udp,local_lock=none,addr=10.75.37.2)
> >
> >
> >
> > $ time dd if=/dev/zero of=/data/test.img bs=10M count=1
> > 1+0 records in
> > 1+0 records out
> > 10485760 bytes (10 MB, 10 MiB) copied, 0.112561 s, 93.2 MB/s
> > real    0m0.188s
> > user    0m0.000s
> > sys     0m0.087s
> >
> > $ time dd if=/dev/zero of=/data/test.img bs=1000M count=1
> > dd: closing output file '/data/test.img': Permission denied
> > real    1m9.093s
> > user    0m0.000s
> > sys     0m1.124s
> >
> > $ strace -f dd if=/dev/zero of=/data/test.img bs=10M count=1
> > execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
> > "bs=10M", "count=1"], 0x7ffec9914328 /* 30 vars */) = 0
> > brk(NULL)                               = 0x5595514e6000
> > access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> > access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
> > fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
> > mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5e4e5d2000
> > close(3)                                = 0
> > access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
> > read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
> > 832) = 832
> > fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
> > mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> > 0) = 0x7f5e4e5d0000
> > mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> > 0) = 0x7f5e4dfd9000
> > mprotect(0x7f5e4e1c0000, 2097152, PROT_NONE) = 0
> > mmap(0x7f5e4e3c0000, 24576, PROT_READ|PROT_WRITE,
> > MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f5e4e3c0000
> > mmap(0x7f5e4e3c6000, 15072, PROT_READ|PROT_WRITE,
> > MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f5e4e3c6000
> > close(3)                                = 0
> > arch_prctl(ARCH_SET_FS, 0x7f5e4e5d1540) = 0
> > mprotect(0x7f5e4e3c0000, 16384, PROT_READ) = 0
> > mprotect(0x55954fd03000, 4096, PROT_READ) = 0
> > mprotect(0x7f5e4e5f1000, 4096, PROT_READ) = 0
> > munmap(0x7f5e4e5d2000, 125550)          = 0
> > rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
> > rt_sigaction(SIGUSR1, {sa_handler=0x55954faf60e0, sa_mask=[INT USR1],
> > sa_flags=SA_RESTORER, sa_restorer=0x7f5e4e017f20}, NULL, 8) = 0
> > rt_sigaction(SIGINT, {sa_handler=0x55954faf60d0, sa_mask=[INT USR1],
> > sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
> > a_restorer=0x7f5e4e017f20}, NULL, 8) = 0
> > brk(NULL)                               = 0x5595514e6000
> > brk(0x559551507000)                     = 0x559551507000
> > openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
> > fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
> > mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f5e4d4c8000
> > close(3)                                = 0
> > openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
> > dup2(3, 0)                              = 0
> > close(3)                                = 0
> > lseek(0, 0, SEEK_CUR)                   = 0
> > openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
> > dup2(3, 1)                              = 1
> > close(3)                                = 0
> > mmap(NULL, 10498048, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
> > -1, 0) = 0x7f5e4cac5000
> > read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> > 10485760) = 10485760
> > write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> > 10485760) = 10485760
> > close(0)                                = 0
> > close(1)                                = 0
> > openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
> > fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
> > read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
> > read(0, "", 4096)                       = 0
> > close(0)                                = 0
> > openat(AT_FDCWD,
> > "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> > -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> > -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
> > ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
> > = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> > 0
> > fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
> > mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f5e4e5f0000
> > close(0)                                = 0
> > write(2, "1+0 records in\n1+0 records out\n", 311+0 records in
> > 1+0 records out
> > ) = 31
> > write(2, "10485760 bytes (10 MB, 10 MiB) c"..., 6010485760 bytes (10
> > MB, 10 MiB) copied, 0.105735 s, 99.2 MB/s) = 60
> > write(2, "\n", 1
> > )                       = 1
> > close(2)                                = 0
> > exit_group(0)                           = ?
> > +++ exited with 0 +++
> >
> >
> >
> > $ strace -f dd if=/dev/zero of=/data/test.img bs=1000M count=1
> > execve("/bin/dd", ["dd", "if=/dev/zero", "of=/data/test.img",
> > "bs=1000M", "count=1"], 0x7fff46397c58 /* 30 vars */) = 0
> > brk(NULL)                               = 0x55a768f09000
> > access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> > access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
> > fstat(3, {st_mode=S_IFREG|0644, st_size=125550, ...}) = 0
> > mmap(NULL, 125550, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f604f357000
> > close(3)                                = 0
> > access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
> > read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\34\2\0\0\0\0\0"...,
> > 832) = 832
> > fstat(3, {st_mode=S_IFREG|0755, st_size=2030544, ...}) = 0
> > mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> > 0) = 0x7f604f355000
> > mmap(NULL, 4131552, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
> > 0) = 0x7f604ed5e000
> > mprotect(0x7f604ef45000, 2097152, PROT_NONE) = 0
> > mmap(0x7f604f145000, 24576, PROT_READ|PROT_WRITE,
> > MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1e7000) = 0x7f604f145000
> > mmap(0x7f604f14b000, 15072, PROT_READ|PROT_WRITE,
> > MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f604f14b000
> > close(3)                                = 0
> > arch_prctl(ARCH_SET_FS, 0x7f604f356540) = 0
> > mprotect(0x7f604f145000, 16384, PROT_READ) = 0
> > mprotect(0x55a767990000, 4096, PROT_READ) = 0
> > mprotect(0x7f604f376000, 4096, PROT_READ) = 0
> > munmap(0x7f604f357000, 125550)          = 0
> > rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
> > rt_sigaction(SIGUSR1, {sa_handler=0x55a7677830e0, sa_mask=[INT USR1],
> > sa_flags=SA_RESTORER, sa_restorer=0x7f604ed9cf20}, NULL, 8) = 0
> > rt_sigaction(SIGINT, {sa_handler=0x55a7677830d0, sa_mask=[INT USR1],
> > sa_flags=SA_RESTORER|SA_NODEFER|SA_RESETHAND,
> > a_restorer=0x7f604ed9cf20}, NULL, 8) = 0
> > brk(NULL)                               = 0x55a768f09000
> > brk(0x55a768f2a000)                     = 0x55a768f2a000
> > openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
> > fstat(3, {st_mode=S_IFREG|0644, st_size=11603728, ...}) = 0
> > mmap(NULL, 11603728, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f604e24d000
> > close(3)                                = 0
> > openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3
> > dup2(3, 0)                              = 0
> > close(3)                                = 0
> > lseek(0, 0, SEEK_CUR)                   = 0
> > openat(AT_FDCWD, "/data/test.img", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
> > dup2(3, 1)                              = 1
> > close(3)                                = 0
> > mmap(NULL, 1048588288, PROT_READ|PROT_WRITE,
> > MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f600fa4a000
> > read(0, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> > 1048576000) = 1048576000
> > write(1, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> > 1048576000) = 1048576000
> > close(0)                                = 0
> > close(1)                                = -1 EACCES (Permission denied)
> > openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 0
> > fstat(0, {st_mode=S_IFREG|0644, st_size=2995, ...}) = 0
> > read(0, "# Locale name alias data base.\n#"..., 4096) = 2995
> > read(0, "", 4096)                       = 0
> > close(0)                                = 0
> > openat(AT_FDCWD,
> > "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> > -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> > -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1
> > ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY)
> > = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/coreutils.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en/LC_MESSAGES/coreutils.mo", O_RDONLY) =
> > 0
> > fstat(0, {st_mode=S_IFREG|0644, st_size=578, ...}) = 0
> > mmap(NULL, 578, PROT_READ, MAP_PRIVATE, 0, 0) = 0x7f604f375000
> > close(0)                                = 0
> > write(2, "dd: ", 4dd: )                     = 4
> > write(2, "closing output file '/data/test."..., 36closing output file
> > '/data/test.img') = 36
> > openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY)
> > = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/libc.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY)
> > = -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1
> > ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) =
> > -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD,
> > "/usr/share/locale-langpack/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) =
> > -1 ENOENT (No such file or directory)
> > openat(AT_FDCWD, "/usr/share/locale-langpack/en/LC_MESSAGES/libc.mo",
> > O_RDONLY) = -1 ENOENT (No such file or directory)
> > write(2, ": Permission denied", 19: Permission denied)     = 19
> > write(2, "\n", 1
> > )                       = 1
> > close(2)                                = 0
> > exit_group(1)                           = ?
> > +++ exited with 1 +++
> >
> > On Wed, Sep 25, 2019 at 12:06 PM Chuck Lever <chuck.lever@oracle.com> wrote:
> >>
> >>
> >>
> >>> On Sep 25, 2019, at 9:48 AM, bfields@fieldses.org wrote:
> >>>
> >>> On Wed, Sep 18, 2019 at 06:36:13PM -0500, Kevin Vasko wrote:
> >>>> We have a new Dell EMC Unity 300 acting as NAS Server that is
> >>>> presenting a NFSv4 NFS Share. Our clients are mostly Ubuntu 18.04.3
> >>>> but issue is also present on CentOS 7.6 systems. We have been
> >>>> struggling with this issue for over a week now and not sure how to
> >>>> resolve it.
> >>>>
> >>>>
> >>>>
> >>>> We are having trouble with NFS Clients completing their writes to the
> >>>> Dell EMC Unity 300 NFS Server when Kerberos is enabled on the NFS
> >>>> Share. I created the NFS Share on the U300, associated it with our
> >>>> FreeIPA (Kerberos/LDAP server) and everything shows successful.
> >>>
> >>> Troubleshooting ideas off the top of my head:
> >>>
> >>> It might be worth trying some other client versions if it's not hard.
> >>>
> >>> It'd be interesting to know what's happening on the network....
> >>> Unfortunately big krb5p writes won't be fun to try to capture and
> >>> examine.
> >>
> >> Wireshark is supposed to have a mechanism for giving it the keys
> >> so that captured GSS data can be decrypted. I've never gotten it
> >> to work, but I didn't try hard. Should be appropriately documented.
> >>
> >>
> >>> Maybe some network or rpc-level statistics would help show if
> >>> there are an unusual number of retries or failures.
> >>
> >>
> >> --
> >> Chuck Lever
> >>
> >>
> >>
>
> --
> Chuck Lever
>
>
>

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-25 18:49       ` Chuck Lever
  2019-09-25 19:10         ` Kevin Vasko
@ 2019-09-25 20:07         ` Bruce Fields
  2019-09-26 15:55           ` Chuck Lever
  1 sibling, 1 reply; 16+ messages in thread
From: Bruce Fields @ 2019-09-25 20:07 UTC (permalink / raw)
  To: Chuck Lever; +Cc: Kevin Vasko, Linux NFS Mailing List

On Wed, Sep 25, 2019 at 11:49:14AM -0700, Chuck Lever wrote:
> Sounds like the NFS server is dropping the connection. With
> GSS enabled, that's usually a sign that the GSS window has
> overflowed.

Would that show up in the rpc statistics on the client somehow?

In that case--I seem to remember there's a way to configure the size of
the client's slot table, maybe lowering that (decreasing the number of
rpc's allowed to be outstanding at a time) would work around the
problem.

Should the client be doing something different to avoid or recover from
overflows of the gss window?

--b.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-25 18:44     ` Kevin Vasko
  2019-09-25 18:49       ` Chuck Lever
@ 2019-09-26  7:30       ` Daniel Kobras
  1 sibling, 0 replies; 16+ messages in thread
From: Daniel Kobras @ 2019-09-26  7:30 UTC (permalink / raw)
  To: Kevin Vasko; +Cc: Linux NFS Mailing List

Hi!

Am 25.09.19 um 20:44 schrieb Kevin Vasko:
> When should the NFS server be sending a packet to the Kerberos server
> to validate the write? Or should it be? I did do packet capture on the
> Unity box but I don’t see anything really useful regarding Kerberos
> authentication. What should I be looking for in the packet traces to
> look for the authentication packets?
You shouldn't see any direct communication between the NFS server and
the KDC. All information is passed indirectly via the NFS client, and
used to establish a GSS context during the initial handshake. In other
words, in your setup, if you see encrypted packets on the wire, Kerberos
has done its job already, and the errors you're seeing are unlikely to
be intrinsic to Kerberos itself, but rather caused by side-effects.

Kind regards,

Daniel
-- 
Daniel Kobras
Principal Architect
Puzzle ITC Deutschland
+49 7071 14316 0
www.puzzle-itc.de

-- 
Puzzle ITC Deutschland GmbH
Sitz der Gesellschaft: Jurastr. 27/1, 72072 
Tübingen

Eingetragen am Amtsgericht Stuttgart HRB 765802
Geschäftsführer: 
Lukas Kallies, Daniel Kobras, Mark Pröhl


^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-25 20:07         ` Bruce Fields
@ 2019-09-26 15:55           ` Chuck Lever
  2019-09-26 16:05             ` Bruce Fields
  2019-09-26 19:55             ` Bruce Fields
  0 siblings, 2 replies; 16+ messages in thread
From: Chuck Lever @ 2019-09-26 15:55 UTC (permalink / raw)
  To: Bruce Fields, Trond Myklebust; +Cc: Kevin Vasko, Linux NFS Mailing List



> On Sep 25, 2019, at 1:07 PM, Bruce Fields <bfields@fieldses.org> wrote:
> 
> On Wed, Sep 25, 2019 at 11:49:14AM -0700, Chuck Lever wrote:
>> Sounds like the NFS server is dropping the connection. With
>> GSS enabled, that's usually a sign that the GSS window has
>> overflowed.
> 
> Would that show up in the rpc statistics on the client somehow?

More likely on the server. The client just sees a disconnect
without any explanation attached.

gss_verify_header is where the checking is done on the server.
Disappointingly, I see some dprintk's in there, but no static
trace events.


> In that case--I seem to remember there's a way to configure the size of
> the client's slot table, maybe lowering that (decreasing the number of
> rpc's allowed to be outstanding at a time) would work around the
> problem.

> Should the client be doing something different to avoid or recover from
> overflows of the gss window?

The client attempts to meter the request stream so that it stays
within the bounds of the GSS sequence number window. The stream
of requests is typically unordered coming out of the transmit
queue.

There is some new code (since maybe v5.0?) that handles the
metering: gss_xmit_need_reencode().


--
Chuck Lever




^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-26 15:55           ` Chuck Lever
@ 2019-09-26 16:05             ` Bruce Fields
  2019-09-26 19:55             ` Bruce Fields
  1 sibling, 0 replies; 16+ messages in thread
From: Bruce Fields @ 2019-09-26 16:05 UTC (permalink / raw)
  To: Chuck Lever; +Cc: Trond Myklebust, Kevin Vasko, Linux NFS Mailing List

On Thu, Sep 26, 2019 at 08:55:17AM -0700, Chuck Lever wrote:
> > On Sep 25, 2019, at 1:07 PM, Bruce Fields <bfields@fieldses.org> wrote:
> > 
> > On Wed, Sep 25, 2019 at 11:49:14AM -0700, Chuck Lever wrote:
> >> Sounds like the NFS server is dropping the connection. With
> >> GSS enabled, that's usually a sign that the GSS window has
> >> overflowed.
> > 
> > Would that show up in the rpc statistics on the client somehow?
> 
> More likely on the server. The client just sees a disconnect
> without any explanation attached.

So watching a count of disconnects might at least tell us something?

> gss_verify_header is where the checking is done on the server.
> Disappointingly, I see some dprintk's in there, but no static
> trace events.

Kevin, was this a Linux server?

--b.

> > In that case--I seem to remember there's a way to configure the size of
> > the client's slot table, maybe lowering that (decreasing the number of
> > rpc's allowed to be outstanding at a time) would work around the
> > problem.
> 
> > Should the client be doing something different to avoid or recover from
> > overflows of the gss window?
> 
> The client attempts to meter the request stream so that it stays
> within the bounds of the GSS sequence number window. The stream
> of requests is typically unordered coming out of the transmit
> queue.
> 
> There is some new code (since maybe v5.0?) that handles the
> metering: gss_xmit_need_reencode().

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-26 15:55           ` Chuck Lever
  2019-09-26 16:05             ` Bruce Fields
@ 2019-09-26 19:55             ` Bruce Fields
  2019-09-30 14:51               ` Kevin Vasko
  1 sibling, 1 reply; 16+ messages in thread
From: Bruce Fields @ 2019-09-26 19:55 UTC (permalink / raw)
  To: Chuck Lever; +Cc: Trond Myklebust, Kevin Vasko, Linux NFS Mailing List

On Thu, Sep 26, 2019 at 08:55:17AM -0700, Chuck Lever wrote:
> > On Sep 25, 2019, at 1:07 PM, Bruce Fields <bfields@fieldses.org> wrote:
> > In that case--I seem to remember there's a way to configure the size of
> > the client's slot table, maybe lowering that (decreasing the number of
> > rpc's allowed to be outstanding at a time) would work around the
> > problem.
> 
> > Should the client be doing something different to avoid or recover from
> > overflows of the gss window?
> 
> The client attempts to meter the request stream so that it stays
> within the bounds of the GSS sequence number window. The stream
> of requests is typically unordered coming out of the transmit
> queue.
> 
> There is some new code (since maybe v5.0?) that handles the
> metering: gss_xmit_need_reencode().

I guess I was thinking he could write a small number (say 2 digits) into
/sys/module/sunrpc/parameters/tcp_max_slot_table_entries (before
mounting, I guess?) and see if the problem's reproducable.

If not, that's a little more evidence that it's the gss sequence window.

(And might be an adequate workaround for now.)

--b.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-26 19:55             ` Bruce Fields
@ 2019-09-30 14:51               ` Kevin Vasko
  2019-09-30 16:19                 ` Bruce Fields
  0 siblings, 1 reply; 16+ messages in thread
From: Kevin Vasko @ 2019-09-30 14:51 UTC (permalink / raw)
  To: Bruce Fields; +Cc: Chuck Lever, Trond Myklebust, Linux NFS Mailing List

What does the GSS window control? I mentioned it in another thread somewhere but I found out that clients with a slower connection seem to not exhibit this issue.

All of these clients are local to the NFS server (in same room, which is in Korea). I’ve got clients in the USA and they don’t seem to exhibit this lockup behavior. I haven’t done extensive testing but we can get 3-4MB/s across the ocean and as of yet I haven’t see a client from the USA lock up like the ones local. It obviously takes a lot longer but haven’t seen it lock up on transferring several 5GB+ files. 

Could the GSS window not be overflowing with the slower connection and we wouldn’t see the issue? 

-Kevin

> On Sep 26, 2019, at 2:55 PM, Bruce Fields <bfields@fieldses.org> wrote:
> 
> On Thu, Sep 26, 2019 at 08:55:17AM -0700, Chuck Lever wrote:
>>>> On Sep 25, 2019, at 1:07 PM, Bruce Fields <bfields@fieldses.org> wrote:
>>> In that case--I seem to remember there's a way to configure the size of
>>> the client's slot table, maybe lowering that (decreasing the number of
>>> rpc's allowed to be outstanding at a time) would work around the
>>> problem.
>> 
>>> Should the client be doing something different to avoid or recover from
>>> overflows of the gss window?
>> 
>> The client attempts to meter the request stream so that it stays
>> within the bounds of the GSS sequence number window. The stream
>> of requests is typically unordered coming out of the transmit
>> queue.
>> 
>> There is some new code (since maybe v5.0?) that handles the
>> metering: gss_xmit_need_reencode().
> 
> I guess I was thinking he could write a small number (say 2 digits) into
> /sys/module/sunrpc/parameters/tcp_max_slot_table_entries (before
> mounting, I guess?) and see if the problem's reproducable.
> 
> If not, that's a little more evidence that it's the gss sequence window.
> 
> (And might be an adequate workaround for now.)
> 
> --b.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
  2019-09-30 14:51               ` Kevin Vasko
@ 2019-09-30 16:19                 ` Bruce Fields
  0 siblings, 0 replies; 16+ messages in thread
From: Bruce Fields @ 2019-09-30 16:19 UTC (permalink / raw)
  To: Kevin Vasko; +Cc: Chuck Lever, Trond Myklebust, Linux NFS Mailing List

On Mon, Sep 30, 2019 at 09:51:23AM -0500, Kevin Vasko wrote:
> What does the GSS window control? I mentioned it in another thread
> somewhere but I found out that clients with a slower connection seem
> to not exhibit this issue.
> 
> All of these clients are local to the NFS server (in same room, which
> is in Korea). I’ve got clients in the USA and they don’t seem to
> exhibit this lockup behavior. I haven’t done extensive testing but we
> can get 3-4MB/s across the ocean and as of yet I haven’t see a client
> from the USA lock up like the ones local. It obviously takes a lot
> longer but haven’t seen it lock up on transferring several 5GB+ files. 
> 
> Could the GSS window not be overflowing with the slower connection and
> we wouldn’t see the issue? 

Each RPCSEC_GSS request has a sequence number that increases by one for
each rpc.  Even if the client is careful to send RPCs in order, they're
often out of order by the time server threads get around to processing
them.  To allow for this, the protocol has the server advertise a window
size (128 on the linux server), and then accept requests with sequence
numbers that fall within that window.

So our theory is that something is happening that is causing requests to
get reordered to such a degree that the server might see a sequence
number more than 128 less than the most recent sequence number it's
seen.

I'd expect the likelihood of that happening to correlate with the number
of rpc's that are in flight at a given time.

Could be that the slower network has a higher (bandwidth * delay)
product, allowing more rpc's in flight?  I don't know.

--b.


> 
> -Kevin
> 
> > On Sep 26, 2019, at 2:55 PM, Bruce Fields <bfields@fieldses.org>
> > wrote:
> > 
> > On Thu, Sep 26, 2019 at 08:55:17AM -0700, Chuck Lever wrote:
> >>>> On Sep 25, 2019, at 1:07 PM, Bruce Fields <bfields@fieldses.org>
> >>>> wrote:
> >>> In that case--I seem to remember there's a way to configure the
> >>> size of the client's slot table, maybe lowering that (decreasing
> >>> the number of rpc's allowed to be outstanding at a time) would
> >>> work around the problem.
> >> 
> >>> Should the client be doing something different to avoid or recover
> >>> from overflows of the gss window?
> >> 
> >> The client attempts to meter the request stream so that it stays
> >> within the bounds of the GSS sequence number window. The stream of
> >> requests is typically unordered coming out of the transmit queue.
> >> 
> >> There is some new code (since maybe v5.0?) that handles the
> >> metering: gss_xmit_need_reencode().
> > 
> > I guess I was thinking he could write a small number (say 2 digits)
> > into /sys/module/sunrpc/parameters/tcp_max_slot_table_entries
> > (before mounting, I guess?) and see if the problem's reproducable.
> > 
> > If not, that's a little more evidence that it's the gss sequence
> > window.
> > 
> > (And might be an adequate workaround for now.)
> > 
> > --b.

^ permalink raw reply	[flat|nested] 16+ messages in thread

* Re: NFSv4 client locks up on larger writes with Kerberos enabled
@ 2019-09-26 16:25 Kevin Vasko
  0 siblings, 0 replies; 16+ messages in thread
From: Kevin Vasko @ 2019-09-26 16:25 UTC (permalink / raw)
  To: Bruce Fields; +Cc: Chuck Lever, Trond Myklebust, Linux NFS Mailing List

Bruce,

Yes. It’s a Dell EMC Unity 300 storage appliance. 

From what I have gathered, under the hood it is running SLES12SP1

3.12.74-60.64.66.1.NEOKERNEL_SLES12SP1 #2 SMP Fri May 17 06;41:36 EDT 2019 x86_64

Unfortunately I only have limited access to the appliance through a “service” account. I do not have root privileges and I can only run certain commands under the service account. 

I’ve got a ticket open with them and it’s been escalated to their “engineering” department but they haven’t provided much insight as of yet.

If you give me some idea on what might help I’ll try to get more info if I can.


-Kevin

> On Sep 26, 2019, at 11:06 AM, Bruce Fields <bfields@fieldses.org> wrote:
> 
> On Thu, Sep 26, 2019 at 08:55:17AM -0700, Chuck Lever wrote:
>>>> On Sep 25, 2019, at 1:07 PM, Bruce Fields <bfields@fieldses.org> wrote:
>>> 
>>> On Wed, Sep 25, 2019 at 11:49:14AM -0700, Chuck Lever wrote:
>>>> Sounds like the NFS server is dropping the connection. With
>>>> GSS enabled, that's usually a sign that the GSS window has
>>>> overflowed.
>>> 
>>> Would that show up in the rpc statistics on the client somehow?
>> 
>> More likely on the server. The client just sees a disconnect
>> without any explanation attached.
> 
> So watching a count of disconnects might at least tell us something?
> 
>> gss_verify_header is where the checking is done on the server.
>> Disappointingly, I see some dprintk's in there, but no static
>> trace events.
> 
> Kevin, was this a Linux server?
> 
> --b.
> 
>>> In that case--I seem to remember there's a way to configure the size of
>>> the client's slot table, maybe lowering that (decreasing the number of
>>> rpc's allowed to be outstanding at a time) would work around the
>>> problem.
>> 
>>> Should the client be doing something different to avoid or recover from
>>> overflows of the gss window?
>> 
>> The client attempts to meter the request stream so that it stays
>> within the bounds of the GSS sequence number window. The stream
>> of requests is typically unordered coming out of the transmit
>> queue.
>> 
>> There is some new code (since maybe v5.0?) that handles the
>> metering: gss_xmit_need_reencode().

^ permalink raw reply	[flat|nested] 16+ messages in thread

end of thread, back to index

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-18 23:36 NFSv4 client locks up on larger writes with Kerberos enabled Kevin Vasko
     [not found] ` <E172CA50-EC89-4072-9C1D-1B825DC3FE8B@lysator.liu.se>
2019-09-19 14:19   ` Kevin Vasko
     [not found]     ` <72E82F62-C743-4783-B81E-98E6A8E35738@lysator.liu.se>
2019-09-19 14:58       ` Kevin Vasko
2019-09-25 16:48 ` bfields
2019-09-25 17:06   ` Chuck Lever
2019-09-25 18:44     ` Kevin Vasko
2019-09-25 18:49       ` Chuck Lever
2019-09-25 19:10         ` Kevin Vasko
2019-09-25 20:07         ` Bruce Fields
2019-09-26 15:55           ` Chuck Lever
2019-09-26 16:05             ` Bruce Fields
2019-09-26 19:55             ` Bruce Fields
2019-09-30 14:51               ` Kevin Vasko
2019-09-30 16:19                 ` Bruce Fields
2019-09-26  7:30       ` Daniel Kobras
2019-09-26 16:25 Kevin Vasko

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