[LU-17482] short read does not set ki_pos correctly

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.16.0
• Affects Version/s: Lustre 2.15.5
• Labels: LTS15
• Severity: 3
• Assignee: Zhenyu Xu
• Reporter: Zhenyu Xu

Description

00000080:00020000:3.0:1706058118.952841:0:7094:0:(file.c:2098:file_read_confine_iter()) event.log.20240123T162623_0: read [198356992, 198361088] over eof, kms 198356992, file_size 198356992.
00000080:00020000:3.0:1706058118.952904:0:7094:0:(file.c:2098:file_read_confine_iter()) event.log.20240123T162623_0: read [198361088, 198365184] over eof, kms 198362740, file_size 198362740.

short read does not set ki_pos correctly, and jumps to wrong position at next read as the file being appended by others.

Issue Links

• is related to: LU-16025 Read past file size after truncate from another client

Comments

[Etienne Aujames]

The CEA hit this on a 2.15.5 in production. This is a blocking issue for them.

[Gerrit Updater]

"Etienne AUJAMES <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/55936
Subject: LU-17482 llite: short read could mess up next read offset
Project: fs/lustre-release
Branch: b2_15
Current Patch Set: 1
Commit: ad7f1f4111ae0f7d6de54e1bbb2506e008bac0d8

[Peter Jones]

Landed for 2.16

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/c/fs/lustre-release/+/53827/
Subject: LU-17482 llite: short read could mess up next read offset
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 35fb413683affe9d41f3521259c260de6caf81d9

[Zhenyu Xu]

https://review.whamcloud.com/c/fs/lustre-release/+/53827/

LU-17482 llite: short read could mess up next read offset

When read reaches EOF, it could read data from stale pagecache, but
we need to restore the iocb->ki_pos so that next read could continue
from the correct offset.