From: Andriy Skulysh <[email protected]> Deadlock isn't detected if 2 threads are trying to grant 2 locks which deadlock on each other. They call ldlm_flock_deadlock() simultaneously and deadlock ins't detected.
The soulition is to add lock to blocking list before calling ldlm_flock_deadlock() Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-1602 Lustre-change: http://review.whamcloud.com/3277 Signed-off-by: Andriy Skulysh <[email protected]> Reviewed-by: Vitaly Fertman <[email protected]> Reviewed-by: Bruce Korb <[email protected]> Reviewed-by: Keith Mannthey <[email protected]> Reviewed-by: Oleg Drokin <[email protected]> Signed-off-by: Peng Tao <[email protected]> Signed-off-by: Andreas Dilger <[email protected]> --- drivers/staging/lustre/lustre/ldlm/ldlm_flock.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c b/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c index aca1073..39973cb 100644 --- a/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c +++ b/drivers/staging/lustre/lustre/ldlm/ldlm_flock.c @@ -198,6 +198,7 @@ ldlm_flock_deadlock(struct ldlm_lock *req, struct ldlm_lock *bl_lock) if (lock == NULL) break; + LASSERT(req != lock); flock = &lock->l_policy_data.l_flock; LASSERT(flock->owner == bl_owner); bl_owner = flock->blocking_owner; @@ -329,18 +330,21 @@ reprocess: RETURN(LDLM_ITER_STOP); } - if (ldlm_flock_deadlock(req, lock)) { - ldlm_flock_destroy(req, mode, *flags); - *err = -EDEADLK; - RETURN(LDLM_ITER_STOP); - } - + /* add lock to blocking list before deadlock + * check to prevent race */ rc = ldlm_flock_blocking_link(req, lock); if (rc) { ldlm_flock_destroy(req, mode, *flags); *err = rc; RETURN(LDLM_ITER_STOP); } + if (ldlm_flock_deadlock(req, lock)) { + ldlm_flock_blocking_unlink(req); + ldlm_flock_destroy(req, mode, *flags); + *err = -EDEADLK; + RETURN(LDLM_ITER_STOP); + } + ldlm_resource_add_lock(res, &res->lr_waiting, req); *flags |= LDLM_FL_BLOCK_GRANTED; RETURN(LDLM_ITER_STOP); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
