1 files changed, 462 insertions, 0 deletions

diff --git a/drivers/staging/lustre/lustre/libcfs/upcall_cache.c b/drivers/staging/lustre/lustre/libcfs/upcall_cache.c
new file mode 100644
index 000000000000..18c68c3493b8
--- /dev/null
+++ b/drivers/staging/lustre/lustre/libcfs/upcall_cache.c
@@ -0,0 +1,462 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ *
+ * libcfs/libcfs/upcall_cache.c
+ *
+ * Supplementary groups cache.
+ */
+#define DEBUG_SUBSYSTEM S_SEC
+
+#include <linux/libcfs/lucache.h>
+
+static struct upcall_cache_entry *alloc_entry(struct upcall_cache *cache,
+					      __u64 key, void *args)
+{
+	struct upcall_cache_entry *entry;
+
+	LIBCFS_ALLOC(entry, sizeof(*entry));
+	if (!entry)
+		return NULL;
+
+	UC_CACHE_SET_NEW(entry);
+	INIT_LIST_HEAD(&entry->ue_hash);
+	entry->ue_key = key;
+	atomic_set(&entry->ue_refcount, 0);
+	init_waitqueue_head(&entry->ue_waitq);
+	if (cache->uc_ops->init_entry)
+		cache->uc_ops->init_entry(entry, args);
+	return entry;
+}
+
+/* protected by cache lock */
+static void free_entry(struct upcall_cache *cache,
+		       struct upcall_cache_entry *entry)
+{
+	if (cache->uc_ops->free_entry)
+		cache->uc_ops->free_entry(cache, entry);
+
+	list_del(&entry->ue_hash);
+	CDEBUG(D_OTHER, "destroy cache entry %p for key "LPU64"\n",
+	       entry, entry->ue_key);
+	LIBCFS_FREE(entry, sizeof(*entry));
+}
+
+static inline int upcall_compare(struct upcall_cache *cache,
+				 struct upcall_cache_entry *entry,
+				 __u64 key, void *args)
+{
+	if (entry->ue_key != key)
+		return -1;
+
+	if (cache->uc_ops->upcall_compare)
+		return cache->uc_ops->upcall_compare(cache, entry, key, args);
+
+	return 0;
+}
+
+static inline int downcall_compare(struct upcall_cache *cache,
+				   struct upcall_cache_entry *entry,
+				   __u64 key, void *args)
+{
+	if (entry->ue_key != key)
+		return -1;
+
+	if (cache->uc_ops->downcall_compare)
+		return cache->uc_ops->downcall_compare(cache, entry, key, args);
+
+	return 0;
+}
+
+static inline void get_entry(struct upcall_cache_entry *entry)
+{
+	atomic_inc(&entry->ue_refcount);
+}
+
+static inline void put_entry(struct upcall_cache *cache,
+			     struct upcall_cache_entry *entry)
+{
+	if (atomic_dec_and_test(&entry->ue_refcount) &&
+	    (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry))) {
+		free_entry(cache, entry);
+	}
+}
+
+static int check_unlink_entry(struct upcall_cache *cache,
+			      struct upcall_cache_entry *entry)
+{
+	if (UC_CACHE_IS_VALID(entry) &&
+	    cfs_time_before(cfs_time_current(), entry->ue_expire))
+		return 0;
+
+	if (UC_CACHE_IS_ACQUIRING(entry)) {
+		if (entry->ue_acquire_expire == 0 ||
+		    cfs_time_before(cfs_time_current(),
+				    entry->ue_acquire_expire))
+			return 0;
+
+		UC_CACHE_SET_EXPIRED(entry);
+		wake_up_all(&entry->ue_waitq);
+	} else if (!UC_CACHE_IS_INVALID(entry)) {
+		UC_CACHE_SET_EXPIRED(entry);
+	}
+
+	list_del_init(&entry->ue_hash);
+	if (!atomic_read(&entry->ue_refcount))
+		free_entry(cache, entry);
+	return 1;
+}
+
+static inline int refresh_entry(struct upcall_cache *cache,
+			 struct upcall_cache_entry *entry)
+{
+	LASSERT(cache->uc_ops->do_upcall);
+	return cache->uc_ops->do_upcall(cache, entry);
+}
+
+struct upcall_cache_entry *upcall_cache_get_entry(struct upcall_cache *cache,
+						  __u64 key, void *args)
+{
+	struct upcall_cache_entry *entry = NULL, *new = NULL, *next;
+	struct list_head *head;
+	wait_queue_t wait;
+	int rc, found;
+	ENTRY;
+
+	LASSERT(cache);
+
+	head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
+find_again:
+	found = 0;
+	spin_lock(&cache->uc_lock);
+	list_for_each_entry_safe(entry, next, head, ue_hash) {
+		/* check invalid & expired items */
+		if (check_unlink_entry(cache, entry))
+			continue;
+		if (upcall_compare(cache, entry, key, args) == 0) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (!found) {
+		if (!new) {
+			spin_unlock(&cache->uc_lock);
+			new = alloc_entry(cache, key, args);
+			if (!new) {
+				CERROR("fail to alloc entry\n");
+				RETURN(ERR_PTR(-ENOMEM));
+			}
+			goto find_again;
+		} else {
+			list_add(&new->ue_hash, head);
+			entry = new;
+		}
+	} else {
+		if (new) {
+			free_entry(cache, new);
+			new = NULL;
+		}
+		list_move(&entry->ue_hash, head);
+	}
+	get_entry(entry);
+
+	/* acquire for new one */
+	if (UC_CACHE_IS_NEW(entry)) {
+		UC_CACHE_SET_ACQUIRING(entry);
+		UC_CACHE_CLEAR_NEW(entry);
+		spin_unlock(&cache->uc_lock);
+		rc = refresh_entry(cache, entry);
+		spin_lock(&cache->uc_lock);
+		entry->ue_acquire_expire =
+			cfs_time_shift(cache->uc_acquire_expire);
+		if (rc < 0) {
+			UC_CACHE_CLEAR_ACQUIRING(entry);
+			UC_CACHE_SET_INVALID(entry);
+			wake_up_all(&entry->ue_waitq);
+			if (unlikely(rc == -EREMCHG)) {
+				put_entry(cache, entry);
+				GOTO(out, entry = ERR_PTR(rc));
+			}
+		}
+	}
+	/* someone (and only one) is doing upcall upon this item,
+	 * wait it to complete */
+	if (UC_CACHE_IS_ACQUIRING(entry)) {
+		long expiry = (entry == new) ?
+			      cfs_time_seconds(cache->uc_acquire_expire) :
+			      MAX_SCHEDULE_TIMEOUT;
+		long left;
+
+		init_waitqueue_entry_current(&wait);
+		add_wait_queue(&entry->ue_waitq, &wait);
+		set_current_state(TASK_INTERRUPTIBLE);
+		spin_unlock(&cache->uc_lock);
+
+		left = waitq_timedwait(&wait, TASK_INTERRUPTIBLE,
+					   expiry);
+
+		spin_lock(&cache->uc_lock);
+		remove_wait_queue(&entry->ue_waitq, &wait);
+		if (UC_CACHE_IS_ACQUIRING(entry)) {
+			/* we're interrupted or upcall failed in the middle */
+			rc = left > 0 ? -EINTR : -ETIMEDOUT;
+			CERROR("acquire for key "LPU64": error %d\n",
+			       entry->ue_key, rc);
+			put_entry(cache, entry);
+			GOTO(out, entry = ERR_PTR(rc));
+		}
+	}
+
+	/* invalid means error, don't need to try again */
+	if (UC_CACHE_IS_INVALID(entry)) {
+		put_entry(cache, entry);
+		GOTO(out, entry = ERR_PTR(-EIDRM));
+	}
+
+	/* check expired
+	 * We can't refresh the existing one because some
+	 * memory might be shared by multiple processes.
+	 */
+	if (check_unlink_entry(cache, entry)) {
+		/* if expired, try again. but if this entry is
+		 * created by me but too quickly turn to expired
+		 * without any error, should at least give a
+		 * chance to use it once.
+		 */
+		if (entry != new) {
+			put_entry(cache, entry);
+			spin_unlock(&cache->uc_lock);
+			new = NULL;
+			goto find_again;
+		}
+	}
+
+	/* Now we know it's good */
+out:
+	spin_unlock(&cache->uc_lock);
+	RETURN(entry);
+}
+EXPORT_SYMBOL(upcall_cache_get_entry);
+
+void upcall_cache_put_entry(struct upcall_cache *cache,
+			    struct upcall_cache_entry *entry)
+{
+	ENTRY;
+
+	if (!entry) {
+		EXIT;
+		return;
+	}
+
+	LASSERT(atomic_read(&entry->ue_refcount) > 0);
+	spin_lock(&cache->uc_lock);
+	put_entry(cache, entry);
+	spin_unlock(&cache->uc_lock);
+	EXIT;
+}
+EXPORT_SYMBOL(upcall_cache_put_entry);
+
+int upcall_cache_downcall(struct upcall_cache *cache, __u32 err, __u64 key,
+			  void *args)
+{
+	struct upcall_cache_entry *entry = NULL;
+	struct list_head *head;
+	int found = 0, rc = 0;
+	ENTRY;
+
+	LASSERT(cache);
+
+	head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
+
+	spin_lock(&cache->uc_lock);
+	list_for_each_entry(entry, head, ue_hash) {
+		if (downcall_compare(cache, entry, key, args) == 0) {
+			found = 1;
+			get_entry(entry);
+			break;
+		}
+	}
+
+	if (!found) {
+		CDEBUG(D_OTHER, "%s: upcall for key "LPU64" not expected\n",
+		       cache->uc_name, key);
+		/* haven't found, it's possible */
+		spin_unlock(&cache->uc_lock);
+		RETURN(-EINVAL);
+	}
+
+	if (err) {
+		CDEBUG(D_OTHER, "%s: upcall for key "LPU64" returned %d\n",
+		       cache->uc_name, entry->ue_key, err);
+		GOTO(out, rc = -EINVAL);
+	}
+
+	if (!UC_CACHE_IS_ACQUIRING(entry)) {
+		CDEBUG(D_RPCTRACE,"%s: found uptodate entry %p (key "LPU64")\n",
+		       cache->uc_name, entry, entry->ue_key);
+		GOTO(out, rc = 0);
+	}
+
+	if (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry)) {
+		CERROR("%s: found a stale entry %p (key "LPU64") in ioctl\n",
+		       cache->uc_name, entry, entry->ue_key);
+		GOTO(out, rc = -EINVAL);
+	}
+
+	spin_unlock(&cache->uc_lock);
+	if (cache->uc_ops->parse_downcall)
+		rc = cache->uc_ops->parse_downcall(cache, entry, args);
+	spin_lock(&cache->uc_lock);
+	if (rc)
+		GOTO(out, rc);
+
+	entry->ue_expire = cfs_time_shift(cache->uc_entry_expire);
+	UC_CACHE_SET_VALID(entry);
+	CDEBUG(D_OTHER, "%s: created upcall cache entry %p for key "LPU64"\n",
+	       cache->uc_name, entry, entry->ue_key);
+out:
+	if (rc) {
+		UC_CACHE_SET_INVALID(entry);
+		list_del_init(&entry->ue_hash);
+	}
+	UC_CACHE_CLEAR_ACQUIRING(entry);
+	spin_unlock(&cache->uc_lock);
+	wake_up_all(&entry->ue_waitq);
+	put_entry(cache, entry);
+
+	RETURN(rc);
+}
+EXPORT_SYMBOL(upcall_cache_downcall);
+
+static void cache_flush(struct upcall_cache *cache, int force)
+{
+	struct upcall_cache_entry *entry, *next;
+	int i;
+	ENTRY;
+
+	spin_lock(&cache->uc_lock);
+	for (i = 0; i < UC_CACHE_HASH_SIZE; i++) {
+		list_for_each_entry_safe(entry, next,
+					 &cache->uc_hashtable[i], ue_hash) {
+			if (!force && atomic_read(&entry->ue_refcount)) {
+				UC_CACHE_SET_EXPIRED(entry);
+				continue;
+			}
+			LASSERT(!atomic_read(&entry->ue_refcount));
+			free_entry(cache, entry);
+		}
+	}
+	spin_unlock(&cache->uc_lock);
+	EXIT;
+}
+
+void upcall_cache_flush_idle(struct upcall_cache *cache)
+{
+	cache_flush(cache, 0);
+}
+EXPORT_SYMBOL(upcall_cache_flush_idle);
+
+void upcall_cache_flush_all(struct upcall_cache *cache)
+{
+	cache_flush(cache, 1);
+}
+EXPORT_SYMBOL(upcall_cache_flush_all);
+
+void upcall_cache_flush_one(struct upcall_cache *cache, __u64 key, void *args)
+{
+	struct list_head *head;
+	struct upcall_cache_entry *entry;
+	int found = 0;
+	ENTRY;
+
+	head = &cache->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
+
+	spin_lock(&cache->uc_lock);
+	list_for_each_entry(entry, head, ue_hash) {
+		if (upcall_compare(cache, entry, key, args) == 0) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (found) {
+		CWARN("%s: flush entry %p: key "LPU64", ref %d, fl %x, "
+		      "cur %lu, ex %ld/%ld\n",
+		      cache->uc_name, entry, entry->ue_key,
+		      atomic_read(&entry->ue_refcount), entry->ue_flags,
+		      cfs_time_current_sec(), entry->ue_acquire_expire,
+		      entry->ue_expire);
+		UC_CACHE_SET_EXPIRED(entry);
+		if (!atomic_read(&entry->ue_refcount))
+			free_entry(cache, entry);
+	}
+	spin_unlock(&cache->uc_lock);
+}
+EXPORT_SYMBOL(upcall_cache_flush_one);
+
+struct upcall_cache *upcall_cache_init(const char *name, const char *upcall,
+				       struct upcall_cache_ops *ops)
+{
+	struct upcall_cache *cache;
+	int i;
+	ENTRY;
+
+	LIBCFS_ALLOC(cache, sizeof(*cache));
+	if (!cache)
+		RETURN(ERR_PTR(-ENOMEM));
+
+	spin_lock_init(&cache->uc_lock);
+	rwlock_init(&cache->uc_upcall_rwlock);
+	for (i = 0; i < UC_CACHE_HASH_SIZE; i++)
+		INIT_LIST_HEAD(&cache->uc_hashtable[i]);
+	strncpy(cache->uc_name, name, sizeof(cache->uc_name) - 1);
+	/* upcall pathname proc tunable */
+	strncpy(cache->uc_upcall, upcall, sizeof(cache->uc_upcall) - 1);
+	cache->uc_entry_expire = 20 * 60;
+	cache->uc_acquire_expire = 30;
+	cache->uc_ops = ops;
+
+	RETURN(cache);
+}
+EXPORT_SYMBOL(upcall_cache_init);
+
+void upcall_cache_cleanup(struct upcall_cache *cache)
+{
+	if (!cache)
+		return;
+	upcall_cache_flush_all(cache);
+	LIBCFS_FREE(cache, sizeof(*cache));
+}
+EXPORT_SYMBOL(upcall_cache_cleanup);