[PATCH 05/14] staging: lustre: ldlm: handle ldlm lock cancel race when evicting client.
From: James Simmons
Date: Sat Feb 18 2017 - 16:50:15 EST
From: Jinshan Xiong <jinshan.xiong@xxxxxxxxx>
A ldlm lock could be canceled simutaneously by ldlm bl thread and
cleanup_resource(). In this case, only one side will win the race
and the other side should wait for the work to complete. Eviction
on group lock is now well supported.
Signed-off-by: Jinshan Xiong <jinshan.xiong@xxxxxxxxx>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6271
Reviewed-on: http://review.whamcloud.com/16456
Reviewed-by: Bobi Jam <bobijam@xxxxxxxxxxx>
Reviewed-by: John L. Hammond <john.hammond@xxxxxxxxx>
Reviewed-by: James Simmons <uja.ornl@xxxxxxxxx>
Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx>
Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
---
drivers/staging/lustre/lustre/include/cl_object.h | 7 +++-
.../lustre/lustre/include/lustre_dlm_flags.h | 3 ++
drivers/staging/lustre/lustre/ldlm/ldlm_lock.c | 46 ++++++++++++++++------
drivers/staging/lustre/lustre/ldlm/ldlm_request.c | 14 ++++++-
drivers/staging/lustre/lustre/ldlm/ldlm_resource.c | 2 +-
drivers/staging/lustre/lustre/llite/vvp_io.c | 1 +
drivers/staging/lustre/lustre/osc/osc_lock.c | 2 +
drivers/staging/lustre/lustre/osc/osc_request.c | 10 ++++-
8 files changed, 68 insertions(+), 17 deletions(-)
diff --git a/drivers/staging/lustre/lustre/include/cl_object.h b/drivers/staging/lustre/lustre/include/cl_object.h
index e4c0c44..12b3222 100644
--- a/drivers/staging/lustre/lustre/include/cl_object.h
+++ b/drivers/staging/lustre/lustre/include/cl_object.h
@@ -1640,9 +1640,14 @@ enum cl_enq_flags {
*/
CEF_PEEK = 0x00000040,
/**
+ * Lock match only. Used by group lock in I/O as group lock
+ * is known to exist.
+ */
+ CEF_LOCK_MATCH = BIT(7),
+ /**
* mask of enq_flags.
*/
- CEF_MASK = 0x0000007f,
+ CEF_MASK = 0x000000ff,
};
/**
diff --git a/drivers/staging/lustre/lustre/include/lustre_dlm_flags.h b/drivers/staging/lustre/lustre/include/lustre_dlm_flags.h
index a0f064d..11331ae 100644
--- a/drivers/staging/lustre/lustre/include/lustre_dlm_flags.h
+++ b/drivers/staging/lustre/lustre/include/lustre_dlm_flags.h
@@ -121,6 +121,9 @@
#define ldlm_set_test_lock(_l) LDLM_SET_FLAG((_l), 1ULL << 19)
#define ldlm_clear_test_lock(_l) LDLM_CLEAR_FLAG((_l), 1ULL << 19)
+/** match lock only */
+#define LDLM_FL_MATCH_LOCK 0x0000000000100000ULL /* bit 20 */
+
/**
* Immediately cancel such locks when they block some other locks. Send
* cancel notification to original lock holder, but expect no reply. This
diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_lock.c b/drivers/staging/lustre/lustre/ldlm/ldlm_lock.c
index 5a94265..16c2a8b 100644
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_lock.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_lock.c
@@ -771,19 +771,11 @@ void ldlm_lock_decref_internal(struct ldlm_lock *lock, enum ldlm_mode mode)
ldlm_lock_decref_internal_nolock(lock, mode);
- if (ldlm_is_local(lock) &&
+ if ((ldlm_is_local(lock) || lock->l_req_mode == LCK_GROUP) &&
!lock->l_readers && !lock->l_writers) {
/* If this is a local lock on a server namespace and this was
* the last reference, cancel the lock.
- */
- CDEBUG(D_INFO, "forcing cancel of local lock\n");
- ldlm_set_cbpending(lock);
- }
-
- if (!lock->l_readers && !lock->l_writers &&
- (ldlm_is_cbpending(lock) || lock->l_req_mode == LCK_GROUP)) {
- /* If we received a blocked AST and this was the last reference,
- * run the callback.
+ *
* Group locks are special:
* They must not go in LRU, but they are not called back
* like non-group locks, instead they are manually released.
@@ -791,6 +783,13 @@ void ldlm_lock_decref_internal(struct ldlm_lock *lock, enum ldlm_mode mode)
* they are manually released, so we remove them when they have
* no more reader or writer references. - LU-6368
*/
+ ldlm_set_cbpending(lock);
+ }
+
+ if (!lock->l_readers && !lock->l_writers && ldlm_is_cbpending(lock)) {
+ /* If we received a blocked AST and this was the last reference,
+ * run the callback.
+ */
LDLM_DEBUG(lock, "final decref done on cbpending lock");
LDLM_LOCK_GET(lock); /* dropped by bl thread */
@@ -1882,6 +1881,19 @@ int ldlm_run_ast_work(struct ldlm_namespace *ns, struct list_head *rpc_list,
return rc;
}
+static bool is_bl_done(struct ldlm_lock *lock)
+{
+ bool bl_done = true;
+
+ if (!ldlm_is_bl_done(lock)) {
+ lock_res_and_lock(lock);
+ bl_done = ldlm_is_bl_done(lock);
+ unlock_res_and_lock(lock);
+ }
+
+ return bl_done;
+}
+
/**
* Helper function to call blocking AST for LDLM lock \a lock in a
* "cancelling" mode.
@@ -1899,8 +1911,20 @@ void ldlm_cancel_callback(struct ldlm_lock *lock)
} else {
LDLM_DEBUG(lock, "no blocking ast");
}
+ /* only canceller can set bl_done bit */
+ ldlm_set_bl_done(lock);
+ wake_up_all(&lock->l_waitq);
+ } else if (!ldlm_is_bl_done(lock)) {
+ struct l_wait_info lwi = { 0 };
+
+ /*
+ * The lock is guaranteed to have been canceled once
+ * returning from this function.
+ */
+ unlock_res_and_lock(lock);
+ l_wait_event(lock->l_waitq, is_bl_done(lock), &lwi);
+ lock_res_and_lock(lock);
}
- ldlm_set_bl_done(lock);
}
/**
diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_request.c b/drivers/staging/lustre/lustre/ldlm/ldlm_request.c
index ebfda36..84eeaa5 100644
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_request.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_request.c
@@ -1029,13 +1029,23 @@ int ldlm_cli_cancel(const struct lustre_handle *lockh,
struct ldlm_lock *lock;
LIST_HEAD(cancels);
- /* concurrent cancels on the same handle can happen */
- lock = ldlm_handle2lock_long(lockh, LDLM_FL_CANCELING);
+ lock = ldlm_handle2lock_long(lockh, 0);
if (!lock) {
LDLM_DEBUG_NOLOCK("lock is already being destroyed");
return 0;
}
+ lock_res_and_lock(lock);
+ /* Lock is being canceled and the caller doesn't want to wait */
+ if (ldlm_is_canceling(lock) && (cancel_flags & LCF_ASYNC)) {
+ unlock_res_and_lock(lock);
+ LDLM_LOCK_RELEASE(lock);
+ return 0;
+ }
+
+ ldlm_set_canceling(lock);
+ unlock_res_and_lock(lock);
+
rc = ldlm_cli_cancel_local(lock);
if (rc == LDLM_FL_LOCAL_ONLY || cancel_flags & LCF_LOCAL) {
LDLM_LOCK_RELEASE(lock);
diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
index d16f5e9..633f65b 100644
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_resource.c
@@ -806,7 +806,7 @@ static void cleanup_resource(struct ldlm_resource *res, struct list_head *q,
unlock_res(res);
ldlm_lock2handle(lock, &lockh);
- rc = ldlm_cli_cancel(&lockh, LCF_ASYNC);
+ rc = ldlm_cli_cancel(&lockh, LCF_LOCAL);
if (rc)
CERROR("ldlm_cli_cancel: %d\n", rc);
LDLM_LOCK_RELEASE(lock);
diff --git a/drivers/staging/lustre/lustre/llite/vvp_io.c b/drivers/staging/lustre/lustre/llite/vvp_io.c
index 3e9cf71..711126e 100644
--- a/drivers/staging/lustre/lustre/llite/vvp_io.c
+++ b/drivers/staging/lustre/lustre/llite/vvp_io.c
@@ -219,6 +219,7 @@ static int vvp_io_one_lock_index(const struct lu_env *env, struct cl_io *io,
if (vio->vui_fd && (vio->vui_fd->fd_flags & LL_FILE_GROUP_LOCKED)) {
descr->cld_mode = CLM_GROUP;
descr->cld_gid = vio->vui_fd->fd_grouplock.lg_gid;
+ enqflags |= CEF_LOCK_MATCH;
} else {
descr->cld_mode = mode;
}
diff --git a/drivers/staging/lustre/lustre/osc/osc_lock.c b/drivers/staging/lustre/lustre/osc/osc_lock.c
index 5f799a4..efecd92 100644
--- a/drivers/staging/lustre/lustre/osc/osc_lock.c
+++ b/drivers/staging/lustre/lustre/osc/osc_lock.c
@@ -167,6 +167,8 @@ static __u64 osc_enq2ldlm_flags(__u32 enqflags)
result |= LDLM_FL_AST_DISCARD_DATA;
if (enqflags & CEF_PEEK)
result |= LDLM_FL_TEST_LOCK;
+ if (enqflags & CEF_LOCK_MATCH)
+ result |= LDLM_FL_MATCH_LOCK;
return result;
}
diff --git a/drivers/staging/lustre/lustre/osc/osc_request.c b/drivers/staging/lustre/lustre/osc/osc_request.c
index c4cfe18..8e22807 100644
--- a/drivers/staging/lustre/lustre/osc/osc_request.c
+++ b/drivers/staging/lustre/lustre/osc/osc_request.c
@@ -2011,7 +2011,7 @@ int osc_enqueue_base(struct obd_export *exp, struct ldlm_res_id *res_id,
}
no_match:
- if (*flags & LDLM_FL_TEST_LOCK)
+ if (*flags & (LDLM_FL_TEST_LOCK | LDLM_FL_MATCH_LOCK))
return -ENOLCK;
if (intent) {
req = ptlrpc_request_alloc(class_exp2cliimp(exp),
@@ -2495,7 +2495,13 @@ static int osc_ldlm_resource_invalidate(struct cfs_hash *hs,
osc = lock->l_ast_data;
cl_object_get(osc2cl(osc));
}
- lock->l_ast_data = NULL;
+
+ /*
+ * clear LDLM_FL_CLEANED flag to make sure it will be canceled
+ * by the 2nd round of ldlm_namespace_clean() call in
+ * osc_import_event().
+ */
+ ldlm_clear_cleaned(lock);
}
unlock_res(res);
--
1.8.3.1