[LU-12828] FLOCK request can be processed twice during resend

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.14.0, Lustre 2.15.0
• Severity: 3
• Assignee: Andriy Skulysh
• Reporter: Andriy Skulysh

Description

It can lead to wrong UNLOCK:

00000080:00010000:0.0:1519718439.198477:0:9470:0:(file.c:3583:ll_file_flock()) inode=[0x200000400:0x1:0x0], pid=9470, owner=0xffff88012d046e00, flags=0x0, mode=2, start=0, end=9223372036854775807
00010000:00010000:0.0:1519718439.200930:0:7184:0:(ldlm_flock.c:314:ldlm_process_flock_lock()) flags 0x0 owner 18446612137364450816 pid 9470 mode 2 start 0 end 9223372036854775807
00000080:00010000:0.0:1519718439.210498:0:9472:0:(file.c:3583:ll_file_flock()) inode=[0x200000400:0x1:0x0], pid=9472, owner=0xffff88013606ce00, flags=0x0, mode=2, start=0, end=9223372036854775807
00000080:00010000:0.0:1519718440.231947:0:9470:0:(file.c:3583:ll_file_flock()) inode=[0x200000400:0x1:0x0], pid=9470, owner=0xffff88012d046e00, flags=0x0, mode=32, start=0, end=9223372036854775807
00000100:00080000:0.0:1519718440.248334:0:5786:0:(client.c:2792:ptlrpc_resend_req()) @@@ going to resend  req@ffff88012d036f00 x1593540148730064/t0(0) o101->lustre-MDT0000-mdc-ffff88009c2e4000@0@lo:12/10 lens 328/344 e 0 to 0 dl 1519718447 ref 2 fl Rpc:/0/ffffffff rc 0/-1
00000001:00020000:0.0:1519718440.248489:0:7185:0:(fail.c:133:__cfs_fail_timeout_set()) cfs_fail_timeout id 998 sleeping for 10000ms
00000001:00020000:0.0:1519718450.233339:0:7184:0:(fail.c:137:__cfs_fail_timeout_set()) cfs_fail_timeout id 999 awake
00010000:00010000:0.0:1519718450.233528:0:7184:0:(ldlm_flock.c:314:ldlm_process_flock_lock()) flags 0x0 owner 18446612137364450816 pid 9470 mode 32 start 0 end 9223372036854775807
00000001:00020000:0.0:1519718450.237109:0:9470:0:(fail.c:133:__cfs_fail_timeout_set()) cfs_fail_timeout id 998 sleeping for 11000ms
00000001:00020000:0.0:1519718450.248712:0:7185:0:(fail.c:137:__cfs_fail_timeout_set()) cfs_fail_timeout id 998 awake
00000001:00020000:0.0:1519718450.249192:0:7185:0:(fail.c:133:__cfs_fail_timeout_set()) cfs_fail_timeout id 998 sleeping for 11000ms
00000001:00020000:0.0:1519718458.253208:0:7184:0:(fail.c:133:__cfs_fail_timeout_set()) cfs_fail_timeout id 998 sleeping for 10000ms
00000001:00020000:0.0:1519718461.237222:0:9470:0:(fail.c:137:__cfs_fail_timeout_set()) cfs_fail_timeout id 998 awake
00010000:00010000:0.0:1519718461.237816:0:9470:0:(ldlm_flock.c:314:ldlm_process_flock_lock()) flags 0x800000000 owner 18446612137364450816 pid 9470 mode 32 start 0 end 9223372036854775807
00010000:00010000:0.0:1519718461.239919:0:9484:0:(ldlm_flock.c:314:ldlm_process_flock_lock()) flags 0x0 owner 18446612137364450816 pid 9470 mode 2 start 0 end 9223372036854775807
00010000:00010000:0.0:1519718461.241247:0:9470:0:(ldlm_flock.c:819:ldlm_flock_completion_ast()) ### client-side enqueue returned a blocked lock, sleeping ns: lustre-MDT0000-mdc-ffff88009c2e4000 lock: ffff8800a0f52800/0x6628549332bf7a4f lrc: 4/0,1 mode: --/PW res: [0x200000400:0x1:0x0].c rrc: 4 type: FLK pid: 9470 [0->9223372036854775807] flags: 0x0 nid: local remote: 0x6628549332bf7a56 expref: -99 pid: 9470 timeout: 0
00000001:00020000:0.0:1519718461.249186:0:7185:0:(fail.c:137:__cfs_fail_timeout_set()) cfs_fail_timeout id 998 awake
00010000:00010000:0.0:1519718461.249206:0:7185:0:(ldlm_flock.c:314:ldlm_process_flock_lock()) flags 0x0 owner 18446612137364450816 pid 9470 mode 32 start 0 end 9223372036854775807
00010000:00020000:0.0:1519718461.251161:0:9470:0:(ldlm_flock.c:885:ldlm_flock_completion_ast()) client-side: only asynchronous lock enqueue can be canceled by CANCELK

The similar scenario is possible with double FLOCK lock which leads to lock on the MDS without any lock on a client