[LU-3] Missing concurrent access control between statahead and VFS create/unlink operation caused dcache confused

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Affects Version/s: Lustre 2.1.0, Lustre 1.8.6
• Severity: 3
• Bugzilla ID: 15,962

Epic

statahead

• Assignee: nasf (Inactive)
• Reporter: nasf (Inactive)

Description

As originally reported on Lustre Bugzilla:
https://bugzilla.lustre.org/show_bug.cgi?id=15962

This issue will cause LBUG on client-side as following:

=====================
LustreError: 10521:0:(namei.c:826:ll_create_node()) ASSERTION(list_empty(&inode->i_dentry)) failed^M
LustreError: 10521:0:(namei.c:826:ll_create_node()) LBUG^M
Pid: 10521, comm: dir_create.sh^M
^M
Call Trace:^M
[<00000000f8e00640>] libcfs_debug_dumpstack+0x50/0x70 [libcfs]^M
[<00000000f8e00d9d>] lbug_with_loc+0x6d/0xd0 [libcfs]^M
[<00000000f8e0c1f6>] libcfs_assertion_failed+0x66/0x70 [libcfs]^M
[<00000000f927c762>] ll_create_nd+0xb62/0xbd0 [lustre]^M
[<00000000c0482b33>] vfs_create+0xc8/0x12f^M
[<00000000c04854e4>] open_namei+0x16a/0x5f9^M
[<00000000c0474b02>] do_filp_open+0x1c/0x31^M
[<00000000c0474b55>] do_sys_open+0x3e/0xae^M
[<00000000c0474bf2>] sys_open+0x16/0x18^M
[<00000000c0404f17>] syscall_call+0x7/0xb^M
=====================

It has been reported many times on lustre-1.8 in racer test. Iit can be reproduced locally with testing racer repeatedly.