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Date: Tue, 24 Mar 2009 09:07:50 -0500
From: David Teigland <teigland@...hat.com>
To: linux-kernel@...r.kernel.org
Subject: [PATCH 5/7] dlm: clear defunct cancel state
When a conversion completes successfully and finds that a cancel
of the convert is still in progress (which is now a moot point),
preemptively clear the state associated with outstanding cancel.
That state could cause a subsequent conversion to be ignored.
Also, improve the consistency and content of error and debug
messages in this area.
Signed-off-by: David Teigland <teigland@...hat.com>
---
fs/dlm/lock.c | 53 +++++++++++++++++++++++++++++++++++++++++++++--------
1 files changed, 45 insertions(+), 8 deletions(-)
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 01e7d39..8cb9204 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -835,7 +835,7 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype)
lkb->lkb_wait_count++;
hold_lkb(lkb);
- log_debug(ls, "add overlap %x cur %d new %d count %d flags %x",
+ log_debug(ls, "addwait %x cur %d overlap %d count %d f %x",
lkb->lkb_id, lkb->lkb_wait_type, mstype,
lkb->lkb_wait_count, lkb->lkb_flags);
goto out;
@@ -851,7 +851,7 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype)
list_add(&lkb->lkb_wait_reply, &ls->ls_waiters);
out:
if (error)
- log_error(ls, "add_to_waiters %x error %d flags %x %d %d %s",
+ log_error(ls, "addwait error %x %d flags %x %d %d %s",
lkb->lkb_id, error, lkb->lkb_flags, mstype,
lkb->lkb_wait_type, lkb->lkb_resource->res_name);
mutex_unlock(&ls->ls_waiters_mutex);
@@ -863,23 +863,55 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype)
request reply on the requestqueue) between dlm_recover_waiters_pre() which
set RESEND and dlm_recover_waiters_post() */
-static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype)
+static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype,
+ struct dlm_message *ms)
{
struct dlm_ls *ls = lkb->lkb_resource->res_ls;
int overlap_done = 0;
if (is_overlap_unlock(lkb) && (mstype == DLM_MSG_UNLOCK_REPLY)) {
+ log_debug(ls, "remwait %x unlock_reply overlap", lkb->lkb_id);
lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK;
overlap_done = 1;
goto out_del;
}
if (is_overlap_cancel(lkb) && (mstype == DLM_MSG_CANCEL_REPLY)) {
+ log_debug(ls, "remwait %x cancel_reply overlap", lkb->lkb_id);
lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
overlap_done = 1;
goto out_del;
}
+ /* Cancel state was preemptively cleared by a successful convert,
+ see next comment, nothing to do. */
+
+ if ((mstype == DLM_MSG_CANCEL_REPLY) &&
+ (lkb->lkb_wait_type != DLM_MSG_CANCEL)) {
+ log_debug(ls, "remwait %x cancel_reply wait_type %d",
+ lkb->lkb_id, lkb->lkb_wait_type);
+ return -1;
+ }
+
+ /* Remove for the convert reply, and premptively remove for the
+ cancel reply. A convert has been granted while there's still
+ an outstanding cancel on it (the cancel is moot and the result
+ in the cancel reply should be 0). We preempt the cancel reply
+ because the app gets the convert result and then can follow up
+ with another op, like convert. This subsequent op would see the
+ lingering state of the cancel and fail with -EBUSY. */
+
+ if ((mstype == DLM_MSG_CONVERT_REPLY) &&
+ (lkb->lkb_wait_type == DLM_MSG_CONVERT) &&
+ is_overlap_cancel(lkb) && ms && !ms->m_result) {
+ log_debug(ls, "remwait %x convert_reply zap overlap_cancel",
+ lkb->lkb_id);
+ lkb->lkb_wait_type = 0;
+ lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
+ lkb->lkb_wait_count--;
+ goto out_del;
+ }
+
/* N.B. type of reply may not always correspond to type of original
msg due to lookup->request optimization, verify others? */
@@ -888,8 +920,8 @@ static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype)
goto out_del;
}
- log_error(ls, "remove_from_waiters lkid %x flags %x types %d %d",
- lkb->lkb_id, lkb->lkb_flags, mstype, lkb->lkb_wait_type);
+ log_error(ls, "remwait error %x reply %d flags %x no wait_type",
+ lkb->lkb_id, mstype, lkb->lkb_flags);
return -1;
out_del:
@@ -899,7 +931,7 @@ static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype)
this would happen */
if (overlap_done && lkb->lkb_wait_type) {
- log_error(ls, "remove_from_waiters %x reply %d give up on %d",
+ log_error(ls, "remwait error %x reply %d wait_type %d overlap",
lkb->lkb_id, mstype, lkb->lkb_wait_type);
lkb->lkb_wait_count--;
lkb->lkb_wait_type = 0;
@@ -921,7 +953,7 @@ static int remove_from_waiters(struct dlm_lkb *lkb, int mstype)
int error;
mutex_lock(&ls->ls_waiters_mutex);
- error = _remove_from_waiters(lkb, mstype);
+ error = _remove_from_waiters(lkb, mstype, NULL);
mutex_unlock(&ls->ls_waiters_mutex);
return error;
}
@@ -936,7 +968,7 @@ static int remove_from_waiters_ms(struct dlm_lkb *lkb, struct dlm_message *ms)
if (ms != &ls->ls_stub_ms)
mutex_lock(&ls->ls_waiters_mutex);
- error = _remove_from_waiters(lkb, ms->m_type);
+ error = _remove_from_waiters(lkb, ms->m_type, ms);
if (ms != &ls->ls_stub_ms)
mutex_unlock(&ls->ls_waiters_mutex);
return error;
@@ -2083,6 +2115,11 @@ static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
lkb->lkb_timeout_cs = args->timeout;
rv = 0;
out:
+ if (rv)
+ log_debug(ls, "validate_lock_args %d %x %x %x %d %d %s",
+ rv, lkb->lkb_id, lkb->lkb_flags, args->flags,
+ lkb->lkb_status, lkb->lkb_wait_type,
+ lkb->lkb_resource->res_name);
return rv;
}
--
1.5.5.6
--
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