[LU-13360] getdents() against empty striped directory always returns 1365 dirents

• Type: Bug
• Resolution: Won't Fix
• Priority: Major
• Affects Version/s: Lustre 2.10.8, Lustre 2.12.4
• Labels: llnl

Environment

Client: opal174 with lustre-2.10.8_5.chaos-1.ch6.x86_64
Servers: zwicky with lustre-2.12.4_2.chaos-1.ch6.x86_64
Both running TOSS 3.5-9rc1 based on RHEL 7.7

Our Lustre tags are on github:
https://github.com/LLNL/lustre/releases/tag/2.10.8_5.chaos
https://github.com/LLNL/lustre/releases/tag/2.12.4_2.chaos

zfs-0.7 based servers

• Assignee: Lai Siyao
• Reporter: Olaf Faaland

Description

Created directory with "lfs mkdir -c2 <thepath>" on Lustre 2.10.8 based client.
May have attempted create subdirs or files (not sure, I'd run a series of mdtest runs across multiple directories, and canceled via Ctrl-C partway through).
ls <thepath> appears to hang.
Running under strace shows that getdents() calls are always returning the same contents, never return EOF.

No error messages are reported on the console of the servers or the client.

[faaland1@opal174 branch:master src] $ps -f
UID        PID  PPID  C STIME TTY          TIME CMD
faaland1 52122 52121  0 09:58 pts/0    00:00:00 -bash
faaland1 59859 52122 99 10:16 pts/0    01:20:38 ls -l /p/lforge/faaland1/mdtest/mdt0 /p/lforge/faaland1/mdtest/mdt1 /p
faaland1 64327 52122  0 11:36 pts/0    00:00:00 ps -f
[faaland1@opal174 branch:master src] $strace -p 59859 2>&1 | head -n4
strace: Process 59859 attached
getdents(3, /* 1365 entries */, 32768)  = 32760
getdents(3, /* 1365 entries */, 32768)  = 32760
getdents(3, /* 1365 entries */, 32768)  = 32760
[faaland1@opal174 branch:master src] $ls -l /proc/59859/fd
total 0
lrwx------ 1 faaland1 faaland1 64 Mar 13 10:41 0 -> /dev/pts/0
lrwx------ 1 faaland1 faaland1 64 Mar 13 10:41 1 -> /dev/pts/0
lrwx------ 1 faaland1 faaland1 64 Mar 13 10:16 2 -> /dev/pts/0
lr-x------ 1 faaland1 faaland1 64 Mar 13 10:41 3 -> /p/lforge/faaland1/mdtest/mdtcount2

The 1365 entries returned are always the same - 676 entries for ".." and 689 entries for "."

    676 {d_ino=144115272398143489, d_off=0, d_reclen=24, d_name="..", d_type=DT_DIR}
    689 {d_ino=144115339574197893, d_off=0, d_reclen=24, d_name=".", d_type=DT_DIR}

I mounted the filesystem on another Lustre 2.10.8 node and ls of that directory produces the same symptoms.

I mounted the file system on a Lustre 2.12.4 node and ls of that directory behaves as normal - getdents() is called twice, once it returns 2 entries, second time it returns 0 entries and 0 bytes (end of directory).