fs/cachefiles/internal.h - linux/kernel/git/dhowells/linux-fs - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-or-later */
 /* General netfs cache on cache files internal defs
  *
  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  */

 #ifdef pr_fmt
 #undef pr_fmt
 #endif

 #define pr_fmt(fmt) "CacheFiles: " fmt


 #include <linux/fscache-cache.h>
 #include <linux/timer.h>
 #include <linux/wait_bit.h>
 #include <linux/cred.h>
 #include <linux/workqueue.h>
 #include <linux/security.h>

 /* Cachefile granularity */
 #define CACHEFILES_GRAN_SIZE	(256 * 1024)
 #define CACHEFILES_DIO_BLOCK_SIZE 4096
 #define CACHEFILES_SIZE_LIMIT	(512 * 8 * CACHEFILES_GRAN_SIZE)

 struct cachefiles_cache;
 struct cachefiles_object;

 extern unsigned cachefiles_debug;
 #define CACHEFILES_DEBUG_KENTER	1
 #define CACHEFILES_DEBUG_KLEAVE	2
 #define CACHEFILES_DEBUG_KDEBUG	4

 #define cachefiles_gfp (__GFP_RECLAIM | __GFP_NORETRY | __GFP_NOMEMALLOC)

 enum cachefiles_content {
 	/* These values are saved on disk */
 	CACHEFILES_CONTENT_NO_DATA	= 0, /* No content stored */
 	CACHEFILES_CONTENT_SINGLE	= 1, /* Content is monolithic, all is present */
 	CACHEFILES_CONTENT_ALL		= 2, /* Content is all present, no map */
 	CACHEFILES_CONTENT_MAP		= 3, /* Content is piecemeal, map in use */
 	CACHEFILES_CONTENT_DIRTY	= 4, /* Content is dirty (only seen on disk) */
 	nr__cachefiles_content
 };

 /*
  * node records
  */
 struct cachefiles_object {
 	struct fscache_object		fscache;	/* fscache handle */
 	struct dentry			*dentry;	/* the file/dir representing this object */
 	struct dentry			*old;		/* backing file */
 	struct file			*backing_file;	/* File open on backing storage */
 	loff_t				i_size;		/* object size */
 	atomic_t			usage;		/* object usage count */
 	unsigned long			flags;
 #define CACHEFILES_OBJECT_USING_TMPFILE	0		/* Object has a tmpfile that need linking */
 	uint8_t				type;		/* object type */
 	bool				new;		/* T if object new */

 	/* Map of the content blocks in the object */
 	enum cachefiles_content		content_info:8;	/* Info about content presence */
 	bool				content_map_changed;
 	u8				*content_map;		/* Content present bitmap */
 	unsigned int			content_map_size;	/* Size of buffer */
 	rwlock_t			content_map_lock;
 };

 extern struct kmem_cache *cachefiles_object_jar;

 /*
  * Cache files cache definition
  */
 struct cachefiles_cache {
 	struct fscache_cache		cache;		/* FS-Cache record */
 	struct vfsmount			*mnt;		/* mountpoint holding the cache */
 	struct dentry			*graveyard;	/* directory into which dead objects go */
 	struct file			*cachefilesd;	/* manager daemon handle */
 	const struct cred		*cache_cred;	/* security override for accessing cache */
 	struct mutex			daemon_mutex;	/* command serialisation mutex */
 	wait_queue_head_t		daemon_pollwq;	/* poll waitqueue for daemon */
 	atomic_t			gravecounter;	/* graveyard uniquifier */
 	atomic_t			f_released;	/* number of objects released lately */
 	atomic_long_t			b_released;	/* number of blocks released lately */
 	unsigned			frun_percent;	/* when to stop culling (% files) */
 	unsigned			fcull_percent;	/* when to start culling (% files) */
 	unsigned			fstop_percent;	/* when to stop allocating (% files) */
 	unsigned			brun_percent;	/* when to stop culling (% blocks) */
 	unsigned			bcull_percent;	/* when to start culling (% blocks) */
 	unsigned			bstop_percent;	/* when to stop allocating (% blocks) */
 	unsigned			bsize;		/* cache's block size */
 	unsigned			bshift;		/* min(ilog2(PAGE_SIZE / bsize), 0) */
 	uint64_t			frun;		/* when to stop culling */
 	uint64_t			fcull;		/* when to start culling */
 	uint64_t			fstop;		/* when to stop allocating */
 	sector_t			brun;		/* when to stop culling */
 	sector_t			bcull;		/* when to start culling */
 	sector_t			bstop;		/* when to stop allocating */
 	unsigned long			flags;
 #define CACHEFILES_READY		0	/* T if cache prepared */
 #define CACHEFILES_DEAD			1	/* T if cache dead */
 #define CACHEFILES_CULLING		2	/* T if cull engaged */
 #define CACHEFILES_STATE_CHANGED	3	/* T if state changed (poll trigger) */
 	char				*rootdirname;	/* name of cache root directory */
 	char				*secctx;	/* LSM security context */
 	char				*tag;		/* cache binding tag */
 };

 #include <trace/events/cachefiles.h>

 static inline
 struct cachefiles_object *cachefiles_cres_object(struct netfs_cache_resources *cres)
 {
 	return container_of(fscache_cres_object(cres),
 			    struct cachefiles_object, fscache);

 }

 /*
  * note change of state for daemon
  */
 static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
 {
 	set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
 	wake_up_all(&cache->daemon_pollwq);
 }

 /*
  * bind.c
  */
 extern int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args);
 extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);

 /*
  * content-map.c
  */
 extern void cachefiles_expand_readahead(struct netfs_cache_resources *cres,
 					loff_t *_start, size_t *_len, loff_t i_size);
 extern enum netfs_read_source cachefiles_prepare_read(struct netfs_read_subrequest *subreq,
 						      loff_t i_size);
 extern u8 *cachefiles_new_content_map(struct cachefiles_object *object,
 				      unsigned int *_size);
 extern void cachefiles_mark_content_map(struct cachefiles_object *object,
 					loff_t start, loff_t len, unsigned int inval_counter);
 extern void cachefiles_expand_content_map(struct cachefiles_object *object, loff_t size);
 extern void cachefiles_shorten_content_map(struct cachefiles_object *object, loff_t new_size);
 extern int cachefiles_prepare_write(struct netfs_cache_resources *cres,
 				    loff_t *_start, size_t *_len, loff_t i_size);
 extern bool cachefiles_load_content_map(struct cachefiles_object *object);
 extern void cachefiles_save_content_map(struct cachefiles_object *object);
 extern int cachefiles_display_object(struct seq_file *m, struct fscache_object *object);

 /*
  * daemon.c
  */
 extern const struct file_operations cachefiles_daemon_fops;

 extern int cachefiles_has_space(struct cachefiles_cache *cache,
 				unsigned fnr, unsigned bnr);

 /*
  * interface.c
  */
 extern const struct fscache_cache_ops cachefiles_cache_ops;
 extern struct fscache_object *cachefiles_grab_object(struct fscache_object *_object,
 						     enum fscache_obj_ref_trace why);
 extern void cachefiles_put_object(struct fscache_object *_object,
 				  enum fscache_obj_ref_trace why);

 void cachefiles_put_object(struct fscache_object *_object,
 			   enum fscache_obj_ref_trace why);

 /*
  * io.c
  */
 extern bool cachefiles_open_object(struct cachefiles_object *obj);

 /*
  * key.c
  */
 extern char *cachefiles_cook_key(const u8 *raw, int keylen, uint8_t type);

 /*
  * namei.c
  */
 extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
 				    struct dentry *dentry);
 extern int cachefiles_delete_object(struct cachefiles_cache *cache,
 				    struct cachefiles_object *object);
 extern bool cachefiles_walk_to_object(struct cachefiles_object *parent,
 				      struct cachefiles_object *object,
 				      const char *key);
 extern struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 					       struct dentry *dir,
 					       const char *name);

 extern int cachefiles_cull(struct cachefiles_cache *cache, struct dentry *dir,
 			   char *filename);

 extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
 				   struct dentry *dir, char *filename);

 extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
 				      struct cachefiles_object *object);

 /*
  * proc.c
  */
 extern atomic_t cachefiles_lookup_histogram[HZ];
 extern atomic_t cachefiles_mkdir_histogram[HZ];
 extern atomic_t cachefiles_create_histogram[HZ];

 #ifdef CONFIG_CACHEFILES_HISTOGRAM
 extern int __init cachefiles_proc_init(void);
 extern void cachefiles_proc_cleanup(void);
 static inline
 void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
 {
 	unsigned long jif = jiffies - start_jif;
 	if (jif >= HZ)
 		jif = HZ - 1;
 	atomic_inc(&histogram[jif]);
 }

 #else
 #define cachefiles_proc_init()		(0)
 #define cachefiles_proc_cleanup()	do {} while (0)
 static inline
 void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
 {
 }
 #endif

 /*
  * rdwr2.c
  */
 extern int cachefiles_begin_operation(struct netfs_cache_resources *);

 /*
  * security.c
  */
 extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
 extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
 					       struct dentry *root,
 					       const struct cred **_saved_cred);

 static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
 					   const struct cred **_saved_cred)
 {
 	*_saved_cred = override_creds(cache->cache_cred);
 }

 static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
 					 const struct cred *saved_cred)
 {
 	revert_creds(saved_cred);
 }

 /*
  * xattr.c
  */
 extern int cachefiles_check_object_type(struct cachefiles_object *object);
 extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
 extern int cachefiles_check_auxdata(struct cachefiles_object *object);
 extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
 					  struct dentry *dentry);
 extern int cachefiles_prepare_to_write(struct fscache_object *object);

 /*
  * error handling
  */

 #define cachefiles_io_error(___cache, FMT, ...)		\
 do {							\
 	pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__);	\
 	fscache_io_error(&(___cache)->cache);		\
 	set_bit(CACHEFILES_DEAD, &(___cache)->flags);	\
 } while (0)

 #define cachefiles_io_error_obj(object, FMT, ...)			\
 do {									\
 	struct cachefiles_cache *___cache;				\
 									\
 	___cache = container_of((object)->fscache.cache,		\
 				struct cachefiles_cache, cache);	\
 	cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__,	\
 			    object->fscache.debug_id);			\
 } while (0)


 /*
  * 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__)


 #if defined(__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_CACHEFILES_DEBUG)
 #define _enter(FMT, ...)				\
 do {							\
 	if (cachefiles_debug & CACHEFILES_DEBUG_KENTER)	\
 		kenter(FMT, ##__VA_ARGS__);		\
 } while (0)

 #define _leave(FMT, ...)				\
 do {							\
 	if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE)	\
 		kleave(FMT, ##__VA_ARGS__);		\
 } while (0)

 #define _debug(FMT, ...)				\
 do {							\
 	if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG)	\
 		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

 #if 1 /* defined(__KDEBUGALL) */

 #define ASSERT(X)							\
 do {									\
 	if (unlikely(!(X))) {						\
 		pr_err("\n");						\
 		pr_err("Assertion failed\n");		\
 		BUG();							\
 	}								\
 } while (0)

 #define ASSERTCMP(X, OP, Y)						\
 do {									\
 	if (unlikely(!((X) OP (Y)))) {					\
 		pr_err("\n");						\
 		pr_err("Assertion failed\n");		\
 		pr_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))) {					\
 		pr_err("\n");						\
 		pr_err("Assertion failed\n");		\
 		BUG();							\
 	}								\
 } while (0)

 #define ASSERTIFCMP(C, X, OP, Y)					\
 do {									\
 	if (unlikely((C) && !((X) OP (Y)))) {				\
 		pr_err("\n");						\
 		pr_err("Assertion failed\n");		\
 		pr_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
	/* SPDX-License-Identifier: GPL-2.0-or-later */
	/* General netfs cache on cache files internal defs
	*
	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	* Written by David Howells (dhowells@redhat.com)
	*/

	#ifdef pr_fmt
	#undef pr_fmt
	#endif

	#define pr_fmt(fmt) "CacheFiles: " fmt


	#include <linux/fscache-cache.h>
	#include <linux/timer.h>
	#include <linux/wait_bit.h>
	#include <linux/cred.h>
	#include <linux/workqueue.h>
	#include <linux/security.h>

	/* Cachefile granularity */
	#define CACHEFILES_GRAN_SIZE (256 * 1024)
	#define CACHEFILES_DIO_BLOCK_SIZE 4096
	#define CACHEFILES_SIZE_LIMIT (512 * 8 * CACHEFILES_GRAN_SIZE)

	struct cachefiles_cache;
	struct cachefiles_object;

	extern unsigned cachefiles_debug;
	#define CACHEFILES_DEBUG_KENTER 1
	#define CACHEFILES_DEBUG_KLEAVE 2
	#define CACHEFILES_DEBUG_KDEBUG 4

	#define cachefiles_gfp (__GFP_RECLAIM \| __GFP_NORETRY \| __GFP_NOMEMALLOC)

	enum cachefiles_content {
	/* These values are saved on disk */
	CACHEFILES_CONTENT_NO_DATA = 0, /* No content stored */
	CACHEFILES_CONTENT_SINGLE = 1, /* Content is monolithic, all is present */
	CACHEFILES_CONTENT_ALL = 2, /* Content is all present, no map */
	CACHEFILES_CONTENT_MAP = 3, /* Content is piecemeal, map in use */
	CACHEFILES_CONTENT_DIRTY = 4, /* Content is dirty (only seen on disk) */
	nr__cachefiles_content
	};

	/*
	* node records
	*/
	struct cachefiles_object {
	struct fscache_object fscache; /* fscache handle */
	struct dentry dentry; / the file/dir representing this object */
	struct dentry old; / backing file */
	struct file backing_file; / File open on backing storage */
	loff_t i_size; /* object size */
	atomic_t usage; /* object usage count */
	unsigned long flags;
	#define CACHEFILES_OBJECT_USING_TMPFILE 0 /* Object has a tmpfile that need linking */
	uint8_t type; /* object type */
	bool new; /* T if object new */

	/* Map of the content blocks in the object */
	enum cachefiles_content content_info:8; /* Info about content presence */
	bool content_map_changed;
	u8 content_map; / Content present bitmap */
	unsigned int content_map_size; /* Size of buffer */
	rwlock_t content_map_lock;
	};

	extern struct kmem_cache *cachefiles_object_jar;

	/*
	* Cache files cache definition
	*/
	struct cachefiles_cache {
	struct fscache_cache cache; /* FS-Cache record */
	struct vfsmount mnt; / mountpoint holding the cache */
	struct dentry graveyard; / directory into which dead objects go */
	struct file cachefilesd; / manager daemon handle */
	const struct cred cache_cred; / security override for accessing cache */
	struct mutex daemon_mutex; /* command serialisation mutex */
	wait_queue_head_t daemon_pollwq; /* poll waitqueue for daemon */
	atomic_t gravecounter; /* graveyard uniquifier */
	atomic_t f_released; /* number of objects released lately */
	atomic_long_t b_released; /* number of blocks released lately */
	unsigned frun_percent; /* when to stop culling (% files) */
	unsigned fcull_percent; /* when to start culling (% files) */
	unsigned fstop_percent; /* when to stop allocating (% files) */
	unsigned brun_percent; /* when to stop culling (% blocks) */
	unsigned bcull_percent; /* when to start culling (% blocks) */
	unsigned bstop_percent; /* when to stop allocating (% blocks) */
	unsigned bsize; /* cache's block size */
	unsigned bshift; /* min(ilog2(PAGE_SIZE / bsize), 0) */
	uint64_t frun; /* when to stop culling */
	uint64_t fcull; /* when to start culling */
	uint64_t fstop; /* when to stop allocating */
	sector_t brun; /* when to stop culling */
	sector_t bcull; /* when to start culling */
	sector_t bstop; /* when to stop allocating */
	unsigned long flags;
	#define CACHEFILES_READY 0 /* T if cache prepared */
	#define CACHEFILES_DEAD 1 /* T if cache dead */
	#define CACHEFILES_CULLING 2 /* T if cull engaged */
	#define CACHEFILES_STATE_CHANGED 3 /* T if state changed (poll trigger) */
	char rootdirname; / name of cache root directory */
	char secctx; / LSM security context */
	char tag; / cache binding tag */
	};

	#include <trace/events/cachefiles.h>

	static inline
	struct cachefiles_object cachefiles_cres_object(struct netfs_cache_resources cres)
	{
	return container_of(fscache_cres_object(cres),
	struct cachefiles_object, fscache);

	}

	/*
	* note change of state for daemon
	*/
	static inline void cachefiles_state_changed(struct cachefiles_cache *cache)
	{
	set_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
	wake_up_all(&cache->daemon_pollwq);
	}

	/*
	* bind.c
	*/
	extern int cachefiles_daemon_bind(struct cachefiles_cache cache, char args);
	extern void cachefiles_daemon_unbind(struct cachefiles_cache *cache);

	/*
	* content-map.c
	*/
	extern void cachefiles_expand_readahead(struct netfs_cache_resources *cres,
	loff_t _start, size_t _len, loff_t i_size);
	extern enum netfs_read_source cachefiles_prepare_read(struct netfs_read_subrequest *subreq,
	loff_t i_size);
	extern u8 cachefiles_new_content_map(struct cachefiles_object object,
	unsigned int *_size);
	extern void cachefiles_mark_content_map(struct cachefiles_object *object,
	loff_t start, loff_t len, unsigned int inval_counter);
	extern void cachefiles_expand_content_map(struct cachefiles_object *object, loff_t size);
	extern void cachefiles_shorten_content_map(struct cachefiles_object *object, loff_t new_size);
	extern int cachefiles_prepare_write(struct netfs_cache_resources *cres,
	loff_t _start, size_t _len, loff_t i_size);
	extern bool cachefiles_load_content_map(struct cachefiles_object *object);
	extern void cachefiles_save_content_map(struct cachefiles_object *object);
	extern int cachefiles_display_object(struct seq_file m, struct fscache_object object);

	/*
	* daemon.c
	*/
	extern const struct file_operations cachefiles_daemon_fops;

	extern int cachefiles_has_space(struct cachefiles_cache *cache,
	unsigned fnr, unsigned bnr);

	/*
	* interface.c
	*/
	extern const struct fscache_cache_ops cachefiles_cache_ops;
	extern struct fscache_object cachefiles_grab_object(struct fscache_object _object,
	enum fscache_obj_ref_trace why);
	extern void cachefiles_put_object(struct fscache_object *_object,
	enum fscache_obj_ref_trace why);

	void cachefiles_put_object(struct fscache_object *_object,
	enum fscache_obj_ref_trace why);

	/*
	* io.c
	*/
	extern bool cachefiles_open_object(struct cachefiles_object *obj);

	/*
	* key.c
	*/
	extern char cachefiles_cook_key(const u8 raw, int keylen, uint8_t type);

	/*
	* namei.c
	*/
	extern void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
	struct dentry *dentry);
	extern int cachefiles_delete_object(struct cachefiles_cache *cache,
	struct cachefiles_object *object);
	extern bool cachefiles_walk_to_object(struct cachefiles_object *parent,
	struct cachefiles_object *object,
	const char *key);
	extern struct dentry cachefiles_get_directory(struct cachefiles_cache cache,
	struct dentry *dir,
	const char *name);

	extern int cachefiles_cull(struct cachefiles_cache cache, struct dentry dir,
	char *filename);

	extern int cachefiles_check_in_use(struct cachefiles_cache *cache,
	struct dentry dir, char filename);

	extern bool cachefiles_commit_tmpfile(struct cachefiles_cache *cache,
	struct cachefiles_object *object);

	/*
	* proc.c
	*/
	extern atomic_t cachefiles_lookup_histogram[HZ];
	extern atomic_t cachefiles_mkdir_histogram[HZ];
	extern atomic_t cachefiles_create_histogram[HZ];

	#ifdef CONFIG_CACHEFILES_HISTOGRAM
	extern int __init cachefiles_proc_init(void);
	extern void cachefiles_proc_cleanup(void);
	static inline
	void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
	{
	unsigned long jif = jiffies - start_jif;
	if (jif >= HZ)
	jif = HZ - 1;
	atomic_inc(&histogram[jif]);
	}

	#else
	#define cachefiles_proc_init() (0)
	#define cachefiles_proc_cleanup() do {} while (0)
	static inline
	void cachefiles_hist(atomic_t histogram[], unsigned long start_jif)
	{
	}
	#endif

	/*
	* rdwr2.c
	*/
	extern int cachefiles_begin_operation(struct netfs_cache_resources *);

	/*
	* security.c
	*/
	extern int cachefiles_get_security_ID(struct cachefiles_cache *cache);
	extern int cachefiles_determine_cache_security(struct cachefiles_cache *cache,
	struct dentry *root,
	const struct cred **_saved_cred);

	static inline void cachefiles_begin_secure(struct cachefiles_cache *cache,
	const struct cred **_saved_cred)
	{
	*_saved_cred = override_creds(cache->cache_cred);
	}

	static inline void cachefiles_end_secure(struct cachefiles_cache *cache,
	const struct cred *saved_cred)
	{
	revert_creds(saved_cred);
	}

	/*
	* xattr.c
	*/
	extern int cachefiles_check_object_type(struct cachefiles_object *object);
	extern int cachefiles_set_object_xattr(struct cachefiles_object *object);
	extern int cachefiles_check_auxdata(struct cachefiles_object *object);
	extern int cachefiles_remove_object_xattr(struct cachefiles_cache *cache,
	struct dentry *dentry);
	extern int cachefiles_prepare_to_write(struct fscache_object *object);

	/*
	* error handling
	*/

	#define cachefiles_io_error(___cache, FMT, ...) \
	do { \
	pr_err("I/O Error: " FMT"\n", ##__VA_ARGS__); \
	fscache_io_error(&(___cache)->cache); \
	set_bit(CACHEFILES_DEAD, &(___cache)->flags); \
	} while (0)

	#define cachefiles_io_error_obj(object, FMT, ...) \
	do { \
	struct cachefiles_cache *___cache; \
	\
	___cache = container_of((object)->fscache.cache, \
	struct cachefiles_cache, cache); \
	cachefiles_io_error(___cache, FMT " [o=%08x]", ##__VA_ARGS__, \
	object->fscache.debug_id); \
	} while (0)


	/*
	* 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__)


	#if defined(__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_CACHEFILES_DEBUG)
	#define _enter(FMT, ...) \
	do { \
	if (cachefiles_debug & CACHEFILES_DEBUG_KENTER) \
	kenter(FMT, ##__VA_ARGS__); \
	} while (0)

	#define _leave(FMT, ...) \
	do { \
	if (cachefiles_debug & CACHEFILES_DEBUG_KLEAVE) \
	kleave(FMT, ##__VA_ARGS__); \
	} while (0)

	#define _debug(FMT, ...) \
	do { \
	if (cachefiles_debug & CACHEFILES_DEBUG_KDEBUG) \
	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

	#if 1 /* defined(__KDEBUGALL) */

	#define ASSERT(X) \
	do { \
	if (unlikely(!(X))) { \
	pr_err("\n"); \
	pr_err("Assertion failed\n"); \
	BUG(); \
	} \
	} while (0)

	#define ASSERTCMP(X, OP, Y) \
	do { \
	if (unlikely(!((X) OP (Y)))) { \
	pr_err("\n"); \
	pr_err("Assertion failed\n"); \
	pr_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))) { \
	pr_err("\n"); \
	pr_err("Assertion failed\n"); \
	BUG(); \
	} \
	} while (0)

	#define ASSERTIFCMP(C, X, OP, Y) \
	do { \
	if (unlikely((C) && !((X) OP (Y)))) { \
	pr_err("\n"); \
	pr_err("Assertion failed\n"); \
	pr_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