From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
If lock state is LOCK_XLOCKDONE, the xlocker can have GSHARED cap.
So when finishing xlock, we may need to revoke the GSHARED cap.
In most cases Locker::_finish_xlock() directly set lock state to
LOCK_LOCK or LOCK_EXCL, which hides the issue. If 'num_rdlock > 0'
or 'num_wrlock > 0' when finishing xlock, the issue reveals.
(lock get stuck in LOCK_XLOCKDONE forever)
The fix is always call Locker::_finish_xlock() when xlock count
reaches zero. _finish_xlock() checks if it can change lock state
to LOCK_EXCL immediately. If not, it uses Locker::eval_gather()
to transit lock state.
Another change of this patch is avoid changing lock state to
LOCK_LOCK directly. because lock in LOCK_XLOCK_DONE state allows
GSHARED cap, lock in LOCK_LOCK state does not.
Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
---
src/mds/Locker.cc | 57 +++++++++++++++++++++++++------------------------------
src/mds/Locker.h | 2 +-
2 files changed, 27 insertions(+), 32 deletions(-)
diff --git a/src/mds/Locker.cc b/src/mds/Locker.cc
index 30e014a..254bbb2 100644
--- a/src/mds/Locker.cc
+++ b/src/mds/Locker.cc
@@ -546,9 +546,7 @@ void Locker::cancel_locking(Mutation *mut, set<CInode*> *pneed_issue)
if (lock->get_type() != CEPH_LOCK_DN) {
bool need_issue = false;
if (lock->get_state() == LOCK_PREXLOCK)
- _finish_xlock(lock, &need_issue);
- if (lock->is_stable())
- eval(lock, &need_issue);
+ _finish_xlock(lock, -1, &need_issue);
if (need_issue)
pneed_issue->insert(static_cast<CInode *>(lock->get_parent()));
}
@@ -1458,19 +1456,29 @@ bool Locker::xlock_start(SimpleLock *lock, MDRequest *mut)
}
}
-void Locker::_finish_xlock(SimpleLock *lock, bool *pneed_issue)
+void Locker::_finish_xlock(SimpleLock *lock, client_t xlocker, bool *pneed_issue)
{
assert(!lock->is_stable());
- if (lock->get_type() != CEPH_LOCK_DN && (static_cast<CInode*>(lock->get_parent())->get_loner()) >= 0)
- lock->set_state(LOCK_EXCL);
- else
- lock->set_state(LOCK_LOCK);
- if (lock->get_type() == CEPH_LOCK_DN && lock->get_parent()->is_replicated() &&
- !lock->is_waiter_for(SimpleLock::WAIT_WR))
- simple_sync(lock, pneed_issue);
- if (lock->get_cap_shift())
- *pneed_issue = true;
- lock->get_parent()->auth_unpin(lock);
+ if (lock->get_num_rdlocks() == 0 &&
+ lock->get_num_wrlocks() == 0 &&
+ lock->get_num_client_lease() == 0 &&
+ lock->get_type() != CEPH_LOCK_DN) {
+ CInode *in = static_cast<CInode*>(lock->get_parent());
+ client_t loner = in->get_target_loner();
+ if (loner >= 0 && (xlocker < 0 || xlocker == loner)) {
+ lock->set_state(LOCK_EXCL);
+ lock->get_parent()->auth_unpin(lock);
+ lock->finish_waiters(SimpleLock::WAIT_STABLE|SimpleLock::WAIT_WR|SimpleLock::WAIT_RD);
+ if (lock->get_cap_shift())
+ *pneed_issue = true;
+ if (lock->get_parent()->is_auth() &&
+ lock->is_stable())
+ try_eval(lock, pneed_issue);
+ return;
+ }
+ }
+ // the xlocker may have CEPH_CAP_GSHARED, need to revoke it if next state is LOCK_LOCK
+ eval_gather(lock, true, pneed_issue);
}
void Locker::xlock_finish(SimpleLock *lock, Mutation *mut, bool *pneed_issue)
@@ -1481,6 +1489,8 @@ void Locker::xlock_finish(SimpleLock *lock, Mutation *mut, bool *pneed_issue)
dout(10) << "xlock_finish on " << *lock << " " << *lock->get_parent() << dendl;
+ client_t xlocker = lock->get_xlock_by_client();
+
// drop ref
lock->put_xlock();
assert(mut);
@@ -1508,24 +1518,9 @@ void Locker::xlock_finish(SimpleLock *lock, Mutation *mut, bool *pneed_issue)
SimpleLock::WAIT_WR |
SimpleLock::WAIT_RD, 0);
} else {
- if (lock->get_num_xlocks() == 0 &&
- lock->get_num_rdlocks() == 0 &&
- lock->get_num_wrlocks() == 0 &&
- lock->get_num_client_lease() == 0) {
- _finish_xlock(lock, &do_issue);
- }
-
- // others waiting?
- lock->finish_waiters(SimpleLock::WAIT_STABLE |
- SimpleLock::WAIT_WR |
- SimpleLock::WAIT_RD, 0);
+ if (lock->get_num_xlocks() == 0)
+ _finish_xlock(lock, xlocker, &do_issue);
}
-
- // eval?
- if (!lock->is_stable())
- eval_gather(lock, false, &do_issue);
- else if (lock->get_parent()->is_auth())
- try_eval(lock, &do_issue);
if (do_issue) {
CInode *in = static_cast<CInode*>(lock->get_parent());
diff --git a/src/mds/Locker.h b/src/mds/Locker.h
index b97307d..b39eff1 100644
--- a/src/mds/Locker.h
+++ b/src/mds/Locker.h
@@ -143,7 +143,7 @@ public:
void remote_wrlock_finish(SimpleLock *lock, int target, Mutation *mut);
bool xlock_start(SimpleLock *lock, MDRequest *mut);
- void _finish_xlock(SimpleLock *lock, bool *pneed_issue);
+ void _finish_xlock(SimpleLock *lock, client_t xlocker, bool *pneed_issue);
void xlock_finish(SimpleLock *lock, Mutation *mut, bool *pneed_issue);
void xlock_export(SimpleLock *lock, Mutation *mut);
--
1.8.1.4
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
