[LU-13615] mdt_big_xattr_get()) ASSERTION( info->mti_big_lmm_used == 0 ) failed

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Labels: llnl
• Severity: 3
• Assignee: Mikhail Pershin
• Reporter: Mikhail Pershin

Description

Recent runs showed the assertion below:

LustreError: 25386:0:(mdt_handler.c:950:mdt_big_xattr_get()) ASSERTION( info->mti_big_lmm_used == 0 ) failed:
LustreError: 25386:0:(mdt_handler.c:950:mdt_big_xattr_get()) LBUG
Pid: 25386, comm: mdt00_003 3.10.0-1062.18.1.el7_lustre.x86_64 #1 SMP Wed May 27 23:19:17 UTC 2020
Call Trace:
[<ffffffffc08bf1dc>] libcfs_call_trace+0x8c/0xc0 [libcfs]
[<ffffffffc08bf28c>] lbug_with_loc+0x4c/0xa0 [libcfs]
[<ffffffffc11643a7>] mdt_big_xattr_get+0x667/0x830 [mdt]
[<ffffffffc11647a7>] mdt_stripe_get+0x237/0x410 [mdt]
[<ffffffffc118a92b>] mdt_reint_migrate+0x116b/0x16c0 [mdt]
[<ffffffffc118af03>] mdt_reint_rec+0x83/0x210 [mdt]
[<ffffffffc1163970>] mdt_reint_internal+0x710/0xae0 [mdt]
[<ffffffffc116ed47>] mdt_reint+0x67/0x140 [mdt]
[<ffffffffc0e3ac0a>] tgt_request_handle+0x96a/0x1640 [ptlrpc]
[<ffffffffc0ddc216>] ptlrpc_server_handle_request+0x256/0xb10 [ptlrpc]
[<ffffffffc0de0744>] ptlrpc_main+0xbb4/0x1550 [ptlrpc]
[<ffffffff998c6321>] kthread+0xd1/0xe0
[<ffffffff99f8ed37>] ret_from_fork_nospec_end+0x0/0x39
[<ffffffffffffffff>] 0xffffffffffffffff

This is result of inappropriate usage of mti_big_lmm buffer in various places. Originally it was introduced to be used for getting big LOV/LMV EA and passing them to reply buffers. Meanwhile it is widely used now for internal server needs. These cases should be distinguished and if there is no intention to return EA in reply then flag {mti_big_lmm_used}} should not be set. Maybe it is worth to rename it as mti_big_lmm_keep to mark that is to be kept until reply is packed.

Issue Links

• is related to: LU-16206 PCC crashes MDS: mdt_big_xattr_get()) ASSERTION( info->mti_big_lmm_used == 0 ) failed
• is related to: LU-13599 LustreError: 30166:0:(service.c:189:ptlrpc_save_lock()) ASSERTION( rs->rs_nlocks < 8 ) failed