fs/fscache/internal.h - third_party/linux - Git at Google

 /* Internal definitions for FS-Cache
  *
  * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */

 /*
  * Lock order, in the order in which multiple locks should be obtained:
  * - fscache_addremove_sem
  * - cookie->lock
  * - cookie->parent->lock
  * - cache->object_list_lock
  * - object->lock
  * - object->parent->lock
  * - cookie->stores_lock
  * - fscache_thread_lock
  *
  */

 #include <linux/fscache-cache.h>
 #include <linux/sched.h>

 #define FSCACHE_MIN_THREADS	4
 #define FSCACHE_MAX_THREADS	32

 /*
  * cache.c
  */
 extern struct list_head fscache_cache_list;
 extern struct rw_semaphore fscache_addremove_sem;

 extern struct fscache_cache *fscache_select_cache_for_object(
 	struct fscache_cookie *);

 /*
  * cookie.c
  */
 extern struct kmem_cache *fscache_cookie_jar;

 extern void fscache_cookie_init_once(void *);
 extern void __fscache_cookie_put(struct fscache_cookie *);

 /*
  * fsdef.c
  */
 extern struct fscache_cookie fscache_fsdef_index;
 extern struct fscache_cookie_def fscache_fsdef_netfs_def;

 /*
  * histogram.c
  */
 #ifdef CONFIG_FSCACHE_HISTOGRAM
 extern atomic_t fscache_obj_instantiate_histogram[HZ];
 extern atomic_t fscache_objs_histogram[HZ];
 extern atomic_t fscache_ops_histogram[HZ];
 extern atomic_t fscache_retrieval_delay_histogram[HZ];
 extern atomic_t fscache_retrieval_histogram[HZ];

 static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif)
 {
 	unsigned long jif = jiffies - start_jif;
 	if (jif >= HZ)
 		jif = HZ - 1;
 	atomic_inc(&histogram[jif]);
 }

 extern const struct file_operations fscache_histogram_fops;

 #else
 #define fscache_hist(hist, start_jif) do {} while (0)
 #endif

 /*
  * main.c
  */
 extern unsigned fscache_defer_lookup;
 extern unsigned fscache_defer_create;
 extern unsigned fscache_debug;
 extern struct kobject *fscache_root;
 extern struct workqueue_struct *fscache_object_wq;
 extern struct workqueue_struct *fscache_op_wq;
 DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);

 static inline bool fscache_object_congested(void)
 {
 	return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
 }

 extern int fscache_wait_bit(void *);
 extern int fscache_wait_bit_interruptible(void *);
 extern int fscache_wait_atomic_t(atomic_t *);

 /*
  * object.c
  */
 extern void fscache_enqueue_object(struct fscache_object *);

 /*
  * object-list.c
  */
 #ifdef CONFIG_FSCACHE_OBJECT_LIST
 extern const struct file_operations fscache_objlist_fops;

 extern void fscache_objlist_add(struct fscache_object *);
 extern void fscache_objlist_remove(struct fscache_object *);
 #else
 #define fscache_objlist_add(object) do {} while(0)
 #define fscache_objlist_remove(object) do {} while(0)
 #endif

 /*
  * operation.c
  */
 extern int fscache_submit_exclusive_op(struct fscache_object *,
 				       struct fscache_operation *);
 extern int fscache_submit_op(struct fscache_object *,
 			     struct fscache_operation *);
 extern int fscache_cancel_op(struct fscache_operation *,
 			     void (*)(struct fscache_operation *));
 extern void fscache_cancel_all_ops(struct fscache_object *);
 extern void fscache_abort_object(struct fscache_object *);
 extern void fscache_start_operations(struct fscache_object *);
 extern void fscache_operation_gc(struct work_struct *);

 /*
  * page.c
  */
 extern int fscache_wait_for_deferred_lookup(struct fscache_cookie *);
 extern int fscache_wait_for_operation_activation(struct fscache_object *,
 						 struct fscache_operation *,
 						 atomic_t *,
 						 atomic_t *,
 						 void (*)(struct fscache_operation *));
 extern void fscache_invalidate_writes(struct fscache_cookie *);

 /*
  * proc.c
  */
 #ifdef CONFIG_PROC_FS
 extern int __init fscache_proc_init(void);
 extern void fscache_proc_cleanup(void);
 #else
 #define fscache_proc_init()	(0)
 #define fscache_proc_cleanup()	do {} while (0)
 #endif

 /*
  * stats.c
  */
 #ifdef CONFIG_FSCACHE_STATS
 extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
 extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];

 extern atomic_t fscache_n_op_pend;
 extern atomic_t fscache_n_op_run;
 extern atomic_t fscache_n_op_enqueue;
 extern atomic_t fscache_n_op_deferred_release;
 extern atomic_t fscache_n_op_release;
 extern atomic_t fscache_n_op_gc;
 extern atomic_t fscache_n_op_cancelled;
 extern atomic_t fscache_n_op_rejected;

 extern atomic_t fscache_n_attr_changed;
 extern atomic_t fscache_n_attr_changed_ok;
 extern atomic_t fscache_n_attr_changed_nobufs;
 extern atomic_t fscache_n_attr_changed_nomem;
 extern atomic_t fscache_n_attr_changed_calls;

 extern atomic_t fscache_n_allocs;
 extern atomic_t fscache_n_allocs_ok;
 extern atomic_t fscache_n_allocs_wait;
 extern atomic_t fscache_n_allocs_nobufs;
 extern atomic_t fscache_n_allocs_intr;
 extern atomic_t fscache_n_allocs_object_dead;
 extern atomic_t fscache_n_alloc_ops;
 extern atomic_t fscache_n_alloc_op_waits;

 extern atomic_t fscache_n_retrievals;
 extern atomic_t fscache_n_retrievals_ok;
 extern atomic_t fscache_n_retrievals_wait;
 extern atomic_t fscache_n_retrievals_nodata;
 extern atomic_t fscache_n_retrievals_nobufs;
 extern atomic_t fscache_n_retrievals_intr;
 extern atomic_t fscache_n_retrievals_nomem;
 extern atomic_t fscache_n_retrievals_object_dead;
 extern atomic_t fscache_n_retrieval_ops;
 extern atomic_t fscache_n_retrieval_op_waits;

 extern atomic_t fscache_n_stores;
 extern atomic_t fscache_n_stores_ok;
 extern atomic_t fscache_n_stores_again;
 extern atomic_t fscache_n_stores_nobufs;
 extern atomic_t fscache_n_stores_oom;
 extern atomic_t fscache_n_store_ops;
 extern atomic_t fscache_n_store_calls;
 extern atomic_t fscache_n_store_pages;
 extern atomic_t fscache_n_store_radix_deletes;
 extern atomic_t fscache_n_store_pages_over_limit;

 extern atomic_t fscache_n_store_vmscan_not_storing;
 extern atomic_t fscache_n_store_vmscan_gone;
 extern atomic_t fscache_n_store_vmscan_busy;
 extern atomic_t fscache_n_store_vmscan_cancelled;
 extern atomic_t fscache_n_store_vmscan_wait;

 extern atomic_t fscache_n_marks;
 extern atomic_t fscache_n_uncaches;

 extern atomic_t fscache_n_acquires;
 extern atomic_t fscache_n_acquires_null;
 extern atomic_t fscache_n_acquires_no_cache;
 extern atomic_t fscache_n_acquires_ok;
 extern atomic_t fscache_n_acquires_nobufs;
 extern atomic_t fscache_n_acquires_oom;

 extern atomic_t fscache_n_invalidates;
 extern atomic_t fscache_n_invalidates_run;

 extern atomic_t fscache_n_updates;
 extern atomic_t fscache_n_updates_null;
 extern atomic_t fscache_n_updates_run;

 extern atomic_t fscache_n_relinquishes;
 extern atomic_t fscache_n_relinquishes_null;
 extern atomic_t fscache_n_relinquishes_waitcrt;
 extern atomic_t fscache_n_relinquishes_retire;

 extern atomic_t fscache_n_cookie_index;
 extern atomic_t fscache_n_cookie_data;
 extern atomic_t fscache_n_cookie_special;

 extern atomic_t fscache_n_object_alloc;
 extern atomic_t fscache_n_object_no_alloc;
 extern atomic_t fscache_n_object_lookups;
 extern atomic_t fscache_n_object_lookups_negative;
 extern atomic_t fscache_n_object_lookups_positive;
 extern atomic_t fscache_n_object_lookups_timed_out;
 extern atomic_t fscache_n_object_created;
 extern atomic_t fscache_n_object_avail;
 extern atomic_t fscache_n_object_dead;

 extern atomic_t fscache_n_checkaux_none;
 extern atomic_t fscache_n_checkaux_okay;
 extern atomic_t fscache_n_checkaux_update;
 extern atomic_t fscache_n_checkaux_obsolete;

 extern atomic_t fscache_n_cop_alloc_object;
 extern atomic_t fscache_n_cop_lookup_object;
 extern atomic_t fscache_n_cop_lookup_complete;
 extern atomic_t fscache_n_cop_grab_object;
 extern atomic_t fscache_n_cop_invalidate_object;
 extern atomic_t fscache_n_cop_update_object;
 extern atomic_t fscache_n_cop_drop_object;
 extern atomic_t fscache_n_cop_put_object;
 extern atomic_t fscache_n_cop_sync_cache;
 extern atomic_t fscache_n_cop_attr_changed;
 extern atomic_t fscache_n_cop_read_or_alloc_page;
 extern atomic_t fscache_n_cop_read_or_alloc_pages;
 extern atomic_t fscache_n_cop_allocate_page;
 extern atomic_t fscache_n_cop_allocate_pages;
 extern atomic_t fscache_n_cop_write_page;
 extern atomic_t fscache_n_cop_uncache_page;
 extern atomic_t fscache_n_cop_dissociate_pages;

 static inline void fscache_stat(atomic_t *stat)
 {
 	atomic_inc(stat);
 }

 static inline void fscache_stat_d(atomic_t *stat)
 {
 	atomic_dec(stat);
 }

 #define __fscache_stat(stat) (stat)

 extern const struct file_operations fscache_stats_fops;
 #else

 #define __fscache_stat(stat) (NULL)
 #define fscache_stat(stat) do {} while (0)
 #define fscache_stat_d(stat) do {} while (0)
 #endif

 /*
  * raise an event on an object
  * - if the event is not masked for that object, then the object is
  *   queued for attention by the thread pool.
  */
 static inline void fscache_raise_event(struct fscache_object *object,
 				       unsigned event)
 {
 	BUG_ON(event >= NR_FSCACHE_OBJECT_EVENTS);
 #if 0
 	printk("*** fscache_raise_event(OBJ%d{%lx},%x)\n",
 	       object->debug_id, object->event_mask, (1 << event));
 #endif
 	if (!test_and_set_bit(event, &object->events) &&
 	    test_bit(event, &object->event_mask))
 		fscache_enqueue_object(object);
 }

 /*
  * drop a reference to a cookie
  */
 static inline void fscache_cookie_put(struct fscache_cookie *cookie)
 {
 	BUG_ON(atomic_read(&cookie->usage) <= 0);
 	if (atomic_dec_and_test(&cookie->usage))
 		__fscache_cookie_put(cookie);
 }

 /*
  * get an extra reference to a netfs retrieval context
  */
 static inline
 void *fscache_get_context(struct fscache_cookie *cookie, void *context)
 {
 	if (cookie->def->get_context)
 		cookie->def->get_context(cookie->netfs_data, context);
 	return context;
 }

 /*
  * release a reference to a netfs retrieval context
  */
 static inline
 void fscache_put_context(struct fscache_cookie *cookie, void *context)
 {
 	if (cookie->def->put_context)
 		cookie->def->put_context(cookie->netfs_data, context);
 }

 /*****************************************************************************/
 /*
  * debug tracing
  */
 #define dbgprintk(FMT, ...) \
 	printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)

 #define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 #define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 #define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)

 #define kjournal(FMT, ...) no_printk(FMT, ##__VA_ARGS__)

 #ifdef __KDEBUG
 #define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
 #define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
 #define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)

 #elif defined(CONFIG_FSCACHE_DEBUG)
 #define _enter(FMT, ...)			\
 do {						\
 	if (__do_kdebug(ENTER))			\
 		kenter(FMT, ##__VA_ARGS__);	\
 } while (0)

 #define _leave(FMT, ...)			\
 do {						\
 	if (__do_kdebug(LEAVE))			\
 		kleave(FMT, ##__VA_ARGS__);	\
 } while (0)

 #define _debug(FMT, ...)			\
 do {						\
 	if (__do_kdebug(DEBUG))			\
 		kdebug(FMT, ##__VA_ARGS__);	\
 } while (0)

 #else
 #define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
 #define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
 #define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
 #endif

 /*
  * determine whether a particular optional debugging point should be logged
  * - we need to go through three steps to persuade cpp to correctly join the
  *   shorthand in FSCACHE_DEBUG_LEVEL with its prefix
  */
 #define ____do_kdebug(LEVEL, POINT) \
 	unlikely((fscache_debug & \
 		  (FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
 #define ___do_kdebug(LEVEL, POINT) \
 	____do_kdebug(LEVEL, POINT)
 #define __do_kdebug(POINT) \
 	___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)

 #define FSCACHE_DEBUG_CACHE	0
 #define FSCACHE_DEBUG_COOKIE	1
 #define FSCACHE_DEBUG_PAGE	2
 #define FSCACHE_DEBUG_OPERATION	3

 #define FSCACHE_POINT_ENTER	1
 #define FSCACHE_POINT_LEAVE	2
 #define FSCACHE_POINT_DEBUG	4

 #ifndef FSCACHE_DEBUG_LEVEL
 #define FSCACHE_DEBUG_LEVEL CACHE
 #endif

 /*
  * assertions
  */
 #if 1 /* defined(__KDEBUGALL) */

 #define ASSERT(X)							\
 do {									\
 	if (unlikely(!(X))) {						\
 		printk(KERN_ERR "\n");					\
 		printk(KERN_ERR "FS-Cache: Assertion failed\n");	\
 		BUG();							\
 	}								\
 } while (0)

 #define ASSERTCMP(X, OP, Y)						\
 do {									\
 	if (unlikely(!((X) OP (Y)))) {					\
 		printk(KERN_ERR "\n");					\
 		printk(KERN_ERR "FS-Cache: Assertion failed\n");	\
 		printk(KERN_ERR "%lx " #OP " %lx is false\n",		\
 		       (unsigned long)(X), (unsigned long)(Y));		\
 		BUG();							\
 	}								\
 } while (0)

 #define ASSERTIF(C, X)							\
 do {									\
 	if (unlikely((C) && !(X))) {					\
 		printk(KERN_ERR "\n");					\
 		printk(KERN_ERR "FS-Cache: Assertion failed\n");	\
 		BUG();							\
 	}								\
 } while (0)

 #define ASSERTIFCMP(C, X, OP, Y)					\
 do {									\
 	if (unlikely((C) && !((X) OP (Y)))) {				\
 		printk(KERN_ERR "\n");					\
 		printk(KERN_ERR "FS-Cache: Assertion failed\n");	\
 		printk(KERN_ERR "%lx " #OP " %lx is false\n",		\
 		       (unsigned long)(X), (unsigned long)(Y));		\
 		BUG();							\
 	}								\
 } while (0)

 #else

 #define ASSERT(X)			do {} while (0)
 #define ASSERTCMP(X, OP, Y)		do {} while (0)
 #define ASSERTIF(C, X)			do {} while (0)
 #define ASSERTIFCMP(C, X, OP, Y)	do {} while (0)

 #endif /* assert or not */
	/* Internal definitions for FS-Cache
	*
	* Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
	* Written by David Howells (dhowells@redhat.com)
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	/*
	* Lock order, in the order in which multiple locks should be obtained:
	* - fscache_addremove_sem
	* - cookie->lock
	* - cookie->parent->lock
	* - cache->object_list_lock
	* - object->lock
	* - object->parent->lock
	* - cookie->stores_lock
	* - fscache_thread_lock
	*
	*/

	#include <linux/fscache-cache.h>
	#include <linux/sched.h>

	#define FSCACHE_MIN_THREADS 4
	#define FSCACHE_MAX_THREADS 32

	/*
	* cache.c
	*/
	extern struct list_head fscache_cache_list;
	extern struct rw_semaphore fscache_addremove_sem;

	extern struct fscache_cache *fscache_select_cache_for_object(
	struct fscache_cookie *);

	/*
	* cookie.c
	*/
	extern struct kmem_cache *fscache_cookie_jar;

	extern void fscache_cookie_init_once(void *);
	extern void __fscache_cookie_put(struct fscache_cookie *);

	/*
	* fsdef.c
	*/
	extern struct fscache_cookie fscache_fsdef_index;
	extern struct fscache_cookie_def fscache_fsdef_netfs_def;

	/*
	* histogram.c
	*/
	#ifdef CONFIG_FSCACHE_HISTOGRAM
	extern atomic_t fscache_obj_instantiate_histogram[HZ];
	extern atomic_t fscache_objs_histogram[HZ];
	extern atomic_t fscache_ops_histogram[HZ];
	extern atomic_t fscache_retrieval_delay_histogram[HZ];
	extern atomic_t fscache_retrieval_histogram[HZ];

	static inline void fscache_hist(atomic_t histogram[], unsigned long start_jif)
	{
	unsigned long jif = jiffies - start_jif;
	if (jif >= HZ)
	jif = HZ - 1;
	atomic_inc(&histogram[jif]);
	}

	extern const struct file_operations fscache_histogram_fops;

	#else
	#define fscache_hist(hist, start_jif) do {} while (0)
	#endif

	/*
	* main.c
	*/
	extern unsigned fscache_defer_lookup;
	extern unsigned fscache_defer_create;
	extern unsigned fscache_debug;
	extern struct kobject *fscache_root;
	extern struct workqueue_struct *fscache_object_wq;
	extern struct workqueue_struct *fscache_op_wq;
	DECLARE_PER_CPU(wait_queue_head_t, fscache_object_cong_wait);

	static inline bool fscache_object_congested(void)
	{
	return workqueue_congested(WORK_CPU_UNBOUND, fscache_object_wq);
	}

	extern int fscache_wait_bit(void *);
	extern int fscache_wait_bit_interruptible(void *);
	extern int fscache_wait_atomic_t(atomic_t *);

	/*
	* object.c
	*/
	extern void fscache_enqueue_object(struct fscache_object *);

	/*
	* object-list.c
	*/
	#ifdef CONFIG_FSCACHE_OBJECT_LIST
	extern const struct file_operations fscache_objlist_fops;

	extern void fscache_objlist_add(struct fscache_object *);
	extern void fscache_objlist_remove(struct fscache_object *);
	#else
	#define fscache_objlist_add(object) do {} while(0)
	#define fscache_objlist_remove(object) do {} while(0)
	#endif

	/*
	* operation.c
	*/
	extern int fscache_submit_exclusive_op(struct fscache_object *,
	struct fscache_operation *);
	extern int fscache_submit_op(struct fscache_object *,
	struct fscache_operation *);
	extern int fscache_cancel_op(struct fscache_operation *,
	void ()(struct fscache_operation ));
	extern void fscache_cancel_all_ops(struct fscache_object *);
	extern void fscache_abort_object(struct fscache_object *);
	extern void fscache_start_operations(struct fscache_object *);
	extern void fscache_operation_gc(struct work_struct *);

	/*
	* page.c
	*/
	extern int fscache_wait_for_deferred_lookup(struct fscache_cookie *);
	extern int fscache_wait_for_operation_activation(struct fscache_object *,
	struct fscache_operation *,
	atomic_t *,
	atomic_t *,
	void ()(struct fscache_operation ));
	extern void fscache_invalidate_writes(struct fscache_cookie *);

	/*
	* proc.c
	*/
	#ifdef CONFIG_PROC_FS
	extern int __init fscache_proc_init(void);
	extern void fscache_proc_cleanup(void);
	#else
	#define fscache_proc_init() (0)
	#define fscache_proc_cleanup() do {} while (0)
	#endif

	/*
	* stats.c
	*/
	#ifdef CONFIG_FSCACHE_STATS
	extern atomic_t fscache_n_ops_processed[FSCACHE_MAX_THREADS];
	extern atomic_t fscache_n_objs_processed[FSCACHE_MAX_THREADS];

	extern atomic_t fscache_n_op_pend;
	extern atomic_t fscache_n_op_run;
	extern atomic_t fscache_n_op_enqueue;
	extern atomic_t fscache_n_op_deferred_release;
	extern atomic_t fscache_n_op_release;
	extern atomic_t fscache_n_op_gc;
	extern atomic_t fscache_n_op_cancelled;
	extern atomic_t fscache_n_op_rejected;

	extern atomic_t fscache_n_attr_changed;
	extern atomic_t fscache_n_attr_changed_ok;
	extern atomic_t fscache_n_attr_changed_nobufs;
	extern atomic_t fscache_n_attr_changed_nomem;
	extern atomic_t fscache_n_attr_changed_calls;

	extern atomic_t fscache_n_allocs;
	extern atomic_t fscache_n_allocs_ok;
	extern atomic_t fscache_n_allocs_wait;
	extern atomic_t fscache_n_allocs_nobufs;
	extern atomic_t fscache_n_allocs_intr;
	extern atomic_t fscache_n_allocs_object_dead;
	extern atomic_t fscache_n_alloc_ops;
	extern atomic_t fscache_n_alloc_op_waits;

	extern atomic_t fscache_n_retrievals;
	extern atomic_t fscache_n_retrievals_ok;
	extern atomic_t fscache_n_retrievals_wait;
	extern atomic_t fscache_n_retrievals_nodata;
	extern atomic_t fscache_n_retrievals_nobufs;
	extern atomic_t fscache_n_retrievals_intr;
	extern atomic_t fscache_n_retrievals_nomem;
	extern atomic_t fscache_n_retrievals_object_dead;
	extern atomic_t fscache_n_retrieval_ops;
	extern atomic_t fscache_n_retrieval_op_waits;

	extern atomic_t fscache_n_stores;
	extern atomic_t fscache_n_stores_ok;
	extern atomic_t fscache_n_stores_again;
	extern atomic_t fscache_n_stores_nobufs;
	extern atomic_t fscache_n_stores_oom;
	extern atomic_t fscache_n_store_ops;
	extern atomic_t fscache_n_store_calls;
	extern atomic_t fscache_n_store_pages;
	extern atomic_t fscache_n_store_radix_deletes;
	extern atomic_t fscache_n_store_pages_over_limit;

	extern atomic_t fscache_n_store_vmscan_not_storing;
	extern atomic_t fscache_n_store_vmscan_gone;
	extern atomic_t fscache_n_store_vmscan_busy;
	extern atomic_t fscache_n_store_vmscan_cancelled;
	extern atomic_t fscache_n_store_vmscan_wait;

	extern atomic_t fscache_n_marks;
	extern atomic_t fscache_n_uncaches;

	extern atomic_t fscache_n_acquires;
	extern atomic_t fscache_n_acquires_null;
	extern atomic_t fscache_n_acquires_no_cache;
	extern atomic_t fscache_n_acquires_ok;
	extern atomic_t fscache_n_acquires_nobufs;
	extern atomic_t fscache_n_acquires_oom;

	extern atomic_t fscache_n_invalidates;
	extern atomic_t fscache_n_invalidates_run;

	extern atomic_t fscache_n_updates;
	extern atomic_t fscache_n_updates_null;
	extern atomic_t fscache_n_updates_run;

	extern atomic_t fscache_n_relinquishes;
	extern atomic_t fscache_n_relinquishes_null;
	extern atomic_t fscache_n_relinquishes_waitcrt;
	extern atomic_t fscache_n_relinquishes_retire;

	extern atomic_t fscache_n_cookie_index;
	extern atomic_t fscache_n_cookie_data;
	extern atomic_t fscache_n_cookie_special;

	extern atomic_t fscache_n_object_alloc;
	extern atomic_t fscache_n_object_no_alloc;
	extern atomic_t fscache_n_object_lookups;
	extern atomic_t fscache_n_object_lookups_negative;
	extern atomic_t fscache_n_object_lookups_positive;
	extern atomic_t fscache_n_object_lookups_timed_out;
	extern atomic_t fscache_n_object_created;
	extern atomic_t fscache_n_object_avail;
	extern atomic_t fscache_n_object_dead;

	extern atomic_t fscache_n_checkaux_none;
	extern atomic_t fscache_n_checkaux_okay;
	extern atomic_t fscache_n_checkaux_update;
	extern atomic_t fscache_n_checkaux_obsolete;

	extern atomic_t fscache_n_cop_alloc_object;
	extern atomic_t fscache_n_cop_lookup_object;
	extern atomic_t fscache_n_cop_lookup_complete;
	extern atomic_t fscache_n_cop_grab_object;
	extern atomic_t fscache_n_cop_invalidate_object;
	extern atomic_t fscache_n_cop_update_object;
	extern atomic_t fscache_n_cop_drop_object;
	extern atomic_t fscache_n_cop_put_object;
	extern atomic_t fscache_n_cop_sync_cache;
	extern atomic_t fscache_n_cop_attr_changed;
	extern atomic_t fscache_n_cop_read_or_alloc_page;
	extern atomic_t fscache_n_cop_read_or_alloc_pages;
	extern atomic_t fscache_n_cop_allocate_page;
	extern atomic_t fscache_n_cop_allocate_pages;
	extern atomic_t fscache_n_cop_write_page;
	extern atomic_t fscache_n_cop_uncache_page;
	extern atomic_t fscache_n_cop_dissociate_pages;

	static inline void fscache_stat(atomic_t *stat)
	{
	atomic_inc(stat);
	}

	static inline void fscache_stat_d(atomic_t *stat)
	{
	atomic_dec(stat);
	}

	#define __fscache_stat(stat) (stat)

	extern const struct file_operations fscache_stats_fops;
	#else

	#define __fscache_stat(stat) (NULL)
	#define fscache_stat(stat) do {} while (0)
	#define fscache_stat_d(stat) do {} while (0)
	#endif

	/*
	* raise an event on an object
	* - if the event is not masked for that object, then the object is
	* queued for attention by the thread pool.
	*/
	static inline void fscache_raise_event(struct fscache_object *object,
	unsigned event)
	{
	BUG_ON(event >= NR_FSCACHE_OBJECT_EVENTS);
	#if 0
	printk("*** fscache_raise_event(OBJ%d{%lx},%x)\n",
	object->debug_id, object->event_mask, (1 << event));
	#endif
	if (!test_and_set_bit(event, &object->events) &&
	test_bit(event, &object->event_mask))
	fscache_enqueue_object(object);
	}

	/*
	* drop a reference to a cookie
	*/
	static inline void fscache_cookie_put(struct fscache_cookie *cookie)
	{
	BUG_ON(atomic_read(&cookie->usage) <= 0);
	if (atomic_dec_and_test(&cookie->usage))
	__fscache_cookie_put(cookie);
	}

	/*
	* get an extra reference to a netfs retrieval context
	*/
	static inline
	void fscache_get_context(struct fscache_cookie cookie, void *context)
	{
	if (cookie->def->get_context)
	cookie->def->get_context(cookie->netfs_data, context);
	return context;
	}

	/*
	* release a reference to a netfs retrieval context
	*/
	static inline
	void fscache_put_context(struct fscache_cookie cookie, void context)
	{
	if (cookie->def->put_context)
	cookie->def->put_context(cookie->netfs_data, context);
	}

	/*****************************************************************************/
	/*
	* debug tracing
	*/
	#define dbgprintk(FMT, ...) \
	printk(KERN_DEBUG "[%-6.6s] "FMT"\n", current->comm, ##__VA_ARGS__)

	#define kenter(FMT, ...) dbgprintk("==> %s("FMT")", __func__, ##__VA_ARGS__)
	#define kleave(FMT, ...) dbgprintk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
	#define kdebug(FMT, ...) dbgprintk(FMT, ##__VA_ARGS__)

	#define kjournal(FMT, ...) no_printk(FMT, ##__VA_ARGS__)

	#ifdef __KDEBUG
	#define _enter(FMT, ...) kenter(FMT, ##__VA_ARGS__)
	#define _leave(FMT, ...) kleave(FMT, ##__VA_ARGS__)
	#define _debug(FMT, ...) kdebug(FMT, ##__VA_ARGS__)

	#elif defined(CONFIG_FSCACHE_DEBUG)
	#define _enter(FMT, ...) \
	do { \
	if (__do_kdebug(ENTER)) \
	kenter(FMT, ##__VA_ARGS__); \
	} while (0)

	#define _leave(FMT, ...) \
	do { \
	if (__do_kdebug(LEAVE)) \
	kleave(FMT, ##__VA_ARGS__); \
	} while (0)

	#define _debug(FMT, ...) \
	do { \
	if (__do_kdebug(DEBUG)) \
	kdebug(FMT, ##__VA_ARGS__); \
	} while (0)

	#else
	#define _enter(FMT, ...) no_printk("==> %s("FMT")", __func__, ##__VA_ARGS__)
	#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
	#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
	#endif

	/*
	* determine whether a particular optional debugging point should be logged
	* - we need to go through three steps to persuade cpp to correctly join the
	* shorthand in FSCACHE_DEBUG_LEVEL with its prefix
	*/
	#define ____do_kdebug(LEVEL, POINT) \
	unlikely((fscache_debug & \
	(FSCACHE_POINT_##POINT << (FSCACHE_DEBUG_ ## LEVEL * 3))))
	#define ___do_kdebug(LEVEL, POINT) \
	____do_kdebug(LEVEL, POINT)
	#define __do_kdebug(POINT) \
	___do_kdebug(FSCACHE_DEBUG_LEVEL, POINT)

	#define FSCACHE_DEBUG_CACHE 0
	#define FSCACHE_DEBUG_COOKIE 1
	#define FSCACHE_DEBUG_PAGE 2
	#define FSCACHE_DEBUG_OPERATION 3

	#define FSCACHE_POINT_ENTER 1
	#define FSCACHE_POINT_LEAVE 2
	#define FSCACHE_POINT_DEBUG 4

	#ifndef FSCACHE_DEBUG_LEVEL
	#define FSCACHE_DEBUG_LEVEL CACHE
	#endif

	/*
	* assertions
	*/
	#if 1 /* defined(__KDEBUGALL) */

	#define ASSERT(X) \
	do { \
	if (unlikely(!(X))) { \
	printk(KERN_ERR "\n"); \
	printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
	BUG(); \
	} \
	} while (0)

	#define ASSERTCMP(X, OP, Y) \
	do { \
	if (unlikely(!((X) OP (Y)))) { \
	printk(KERN_ERR "\n"); \
	printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
	printk(KERN_ERR "%lx " #OP " %lx is false\n", \
	(unsigned long)(X), (unsigned long)(Y)); \
	BUG(); \
	} \
	} while (0)

	#define ASSERTIF(C, X) \
	do { \
	if (unlikely((C) && !(X))) { \
	printk(KERN_ERR "\n"); \
	printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
	BUG(); \
	} \
	} while (0)

	#define ASSERTIFCMP(C, X, OP, Y) \
	do { \
	if (unlikely((C) && !((X) OP (Y)))) { \
	printk(KERN_ERR "\n"); \
	printk(KERN_ERR "FS-Cache: Assertion failed\n"); \
	printk(KERN_ERR "%lx " #OP " %lx is false\n", \
	(unsigned long)(X), (unsigned long)(Y)); \
	BUG(); \
	} \
	} while (0)

	#else

	#define ASSERT(X) do {} while (0)
	#define ASSERTCMP(X, OP, Y) do {} while (0)
	#define ASSERTIF(C, X) do {} while (0)
	#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)

	#endif /* assert or not */