[LU-12017] Truncate vs setxattr deadlock with DoM

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.13.0, Lustre 2.12.3
• Labels: patch
• Severity: 3
• Assignee: Mikhail Pershin
• Reporter: Andriy Skulysh

Description

setxattr takes inode lock and sends reint to MDS.
truncate takes MDS_INODELOCK_DOM lock and  wants to acquire inode lock.

PID: 14942 TASK: ffff88007659cf10 CPU: 3 COMMAND: "truncate"
 #0 [ffff88011f397af8] __schedule at ffffffff816b3de4
 #1 [ffff88011f397b88] schedule_preempt_disabled at ffffffff816b5329
 #2 [ffff88011f397b98] __mutex_lock_slowpath at ffffffff816b30d7
 #3 [ffff88011f397bf0] mutex_lock at ffffffff816b24bf
 #4 [ffff88011f397c08] vvp_io_setattr_start at ffffffffc118993d [lustre]
 #5 [ffff88011f397c40] cl_io_start at ffffffffc06e7a25 [obdclass]
 #6 [ffff88011f397c68] cl_io_loop at ffffffffc06e9e01 [obdclass]
 #7 [ffff88011f397cd8] cl_setattr_ost at ffffffffc11847ef [lustre]
 #8 [ffff88011f397d28] ll_setattr_raw at ffffffffc11614d8 [lustre]
 #9 [ffff88011f397df0] ll_setattr at ffffffffc11617d3 [lustre]
#10 [ffff88011f397e00] notify_change at ffffffff81223bc4
#11 [ffff88011f397e48] do_truncate at ffffffff81203445
#12 [ffff88011f397ec0] vfs_truncate at ffffffff8120361c
#13 [ffff88011f397ef8] do_sys_truncate at ffffffff8120370c
#14 [ffff88011f397f40] sys_truncate at ffffffff812038de

PID: 15194 TASK: ffff880077f18000 CPU: 1 COMMAND: "setfattr"
 #0 [ffff88011d33b8b8] __schedule at ffffffff816b3de4
 #1 [ffff88011d33b948] schedule at ffffffff816b4409
 #2 [ffff88011d33b958] schedule_timeout at ffffffff816b1ca4
 #3 [ffff88011d33ba00] ptlrpc_set_wait at ffffffffc09070a0 [ptlrpc]
 #4 [ffff88011d33baf0] ptlrpc_queue_wait at ffffffffc09074e3 [ptlrpc]
 #5 [ffff88011d33bb10] mdc_xattr_common at ffffffffc0b52186 [mdc]
 #6 [ffff88011d33bb90] mdc_setxattr at ffffffffc0b522de [mdc]
 #7 [ffff88011d33bbd0] lmv_setxattr at ffffffffc0872524 [lmv]
 #8 [ffff88011d33bc48] ll_xattr_set_common at ffffffffc1175b54 [lustre]
 #9 [ffff88011d33bcc8] ll_xattr_set_common_3_11 at ffffffffc11769ab [lustre]
#10 [ffff88011d33bcd8] generic_setxattr at ffffffff8122c2d8
#11 [ffff88011d33bd10] __vfs_setxattr_noperm at ffffffff8122cb45
#12 [ffff88011d33bd58] vfs_setxattr at ffffffff8122cd45
#13 [ffff88011d33bd98] setxattr at ffffffff8122ce7e
#14 [ffff88011d33bef0] sys_setxattr at ffffffff8122d177

MDS locks are for different bits MDS_INODELOCK_UPDATE|MDS_INODELOCK_XATTR vs
MDS_INODELOCK_DOM but they blocks each other if some blocking lock was present earlier because Lustre tries to grant only first lock in the waiting list.

Issue Links

• is related to: LU-13456 Fix LU-12017
• is related to: LU-13467 truncate deadlock with DoM files
• is related to: LU-11285 don't stop on the first blocked lock in ldlm_reprocess_queue()