[LU-16055] old file version returned on some client

Fri, 29 Jul 2022 07:20:13 +0000

On some clients (9 out of 242), the wrong version of a file is read, unless direct I/O is used. The file is small and completely stored on the mdt:

[wgs34] /root # lfs getstripe /lustre/fs24/files/test.py
/lustre/fs24/files/test.py
lcm_layout_gen: 2
lcm_mirror_count: 1
lcm_entry_count: 2
lcme_id: 1
lcme_mirror_id: 0
lcme_flags: init
lcme_extent.e_start: 0
lcme_extent.e_end: 524288
lmm_stripe_count: 0
lmm_stripe_size: 524288
lmm_pattern: mdt
lmm_layout_gen: 0
lmm_stripe_offset: 0

lcme_id: 2
lcme_mirror_id: 0
lcme_flags: 0
lcme_extent.e_start: 524288
lcme_extent.e_end: EOF
lmm_stripe_count: 1
lmm_stripe_size: 524288
lmm_pattern: raid0
lmm_layout_gen: 0
lmm_stripe_offset: -1

If I copy the file on one of the affected machines, it is the old overwritten version. If I use direct I/O, the file has the correct content:

[pax9-02] /root # dd if=/lustre/fs24/files/test.py of=bla iflag=direct bs=4096
0+1 records in
0+1 records out
642 bytes (642 B) copied, 0.000977625 s, 657 kB/s

There are no Lustre errors on the client or server. sync or lflush had no effect, but umounting and remounting the file system fixed this.

Whamcloud Community JIRA

[LU-16055] old file version returned on some client