[linux-2.6-block.git] / include / linux / dcache.h

#ifndef __LINUX_DCACHE_H
#define __LINUX_DCACHE_H

#include <linux/atomic.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/rculist_bl.h>
#include <linux/spinlock.h>
#include <linux/seqlock.h>
#include <linux/cache.h>
#include <linux/rcupdate.h>
#include <linux/lockref.h>

struct nameidata;
struct path;
struct vfsmount;

/*
 * linux/include/linux/dcache.h
 *
 * Dirent cache data structures
 *
 * (C) Copyright 1997 Thomas Schoebel-Theuer,
 * with heavy changes by Linus Torvalds
 */

#define IS_ROOT(x) ((x) == (x)->d_parent)

/* The hash is always the low bits of hash_len */
#ifdef __LITTLE_ENDIAN
 #define HASH_LEN_DECLARE u32 hash; u32 len;
#else
 #define HASH_LEN_DECLARE u32 len; u32 hash;
#endif

/*
 * "quick string" -- eases parameter passing, but more importantly
 * saves "metadata" about the string (ie length and the hash).
 *
 * hash comes first so it snuggles against d_parent in the
 * dentry.
 */
struct qstr {
	union {
		struct {
			HASH_LEN_DECLARE;
		};
		u64 hash_len;
	};
	const unsigned char *name;
};

#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
#define hashlen_hash(hashlen) ((u32) (hashlen))
#define hashlen_len(hashlen)  ((u32)((hashlen) >> 32))

struct dentry_stat_t {
	long nr_dentry;
	long nr_unused;
	long age_limit;          /* age in seconds */
	long want_pages;         /* pages requested by system */
	long dummy[2];
};
extern struct dentry_stat_t dentry_stat;

/* Name hashing routines. Initial hash value */
/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
#define init_name_hash()		0

/* partial hash update function. Assume roughly 4 bits per character */
static inline unsigned long
partial_name_hash(unsigned long c, unsigned long prevhash)
{
	return (prevhash + (c << 4) + (c >> 4)) * 11;
}

/*
 * Finally: cut down the number of bits to a int value (and try to avoid
 * losing bits)
 */
static inline unsigned long end_name_hash(unsigned long hash)
{
	return (unsigned int) hash;
}

/* Compute the hash for a name string. */
extern unsigned int full_name_hash(const unsigned char *, unsigned int);

/*
 * Try to keep struct dentry aligned on 64 byte cachelines (this will
 * give reasonable cacheline footprint with larger lines without the
 * large memory footprint increase).
 */
#ifdef CONFIG_64BIT
# define DNAME_INLINE_LEN 32 /* 192 bytes */
#else
# ifdef CONFIG_SMP
#  define DNAME_INLINE_LEN 36 /* 128 bytes */
# else
#  define DNAME_INLINE_LEN 40 /* 128 bytes */
# endif
#endif

#define d_lock	d_lockref.lock

struct dentry {
	/* RCU lookup touched fields */
	unsigned int d_flags;		/* protected by d_lock */
	seqcount_t d_seq;		/* per dentry seqlock */
	struct hlist_bl_node d_hash;	/* lookup hash list */
	struct dentry *d_parent;	/* parent directory */
	struct qstr d_name;
	struct inode *d_inode;		/* Where the name belongs to - NULL is
					 * negative */
	unsigned char d_iname[DNAME_INLINE_LEN];	/* small names */

	/* Ref lookup also touches following */
	struct lockref d_lockref;	/* per-dentry lock and refcount */
	const struct dentry_operations *d_op;
	struct super_block *d_sb;	/* The root of the dentry tree */
	unsigned long d_time;		/* used by d_revalidate */
	void *d_fsdata;			/* fs-specific data */

	struct list_head d_lru;		/* LRU list */
	/*
	 * d_child and d_rcu can share memory
	 */
	union {
		struct list_head d_child;	/* child of parent list */
	 	struct rcu_head d_rcu;
	} d_u;
	struct list_head d_subdirs;	/* our children */
	struct hlist_node d_alias;	/* inode alias list */
};

/*
 * dentry->d_lock spinlock nesting subclasses:
 *
 * 0: normal
 * 1: nested
 */
enum dentry_d_lock_class
{
	DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
	DENTRY_D_LOCK_NESTED
};

struct dentry_operations {
	int (*d_revalidate)(struct dentry *, unsigned int);
	int (*d_weak_revalidate)(struct dentry *, unsigned int);
	int (*d_hash)(const struct dentry *, struct qstr *);
	int (*d_compare)(const struct dentry *, const struct dentry *,
			unsigned int, const char *, const struct qstr *);
	int (*d_delete)(const struct dentry *);
	void (*d_release)(struct dentry *);
	void (*d_prune)(struct dentry *);
	void (*d_iput)(struct dentry *, struct inode *);
	char *(*d_dname)(struct dentry *, char *, int);
	struct vfsmount *(*d_automount)(struct path *);
	int (*d_manage)(struct dentry *, bool);
} ____cacheline_aligned;

/*
 * Locking rules for dentry_operations callbacks are to be found in
 * Documentation/filesystems/Locking. Keep it updated!
 *
 * FUrther descriptions are found in Documentation/filesystems/vfs.txt.
 * Keep it updated too!
 */

/* d_flags entries */
#define DCACHE_OP_HASH		0x0001
#define DCACHE_OP_COMPARE	0x0002
#define DCACHE_OP_REVALIDATE	0x0004
#define DCACHE_OP_DELETE	0x0008
#define DCACHE_OP_PRUNE         0x0010

#define	DCACHE_DISCONNECTED	0x0020
     /* This dentry is possibly not currently connected to the dcache tree, in
      * which case its parent will either be itself, or will have this flag as
      * well.  nfsd will not use a dentry with this bit set, but will first
      * endeavour to clear the bit either by discovering that it is connected,
      * or by performing lookup operations.   Any filesystem which supports
      * nfsd_operations MUST have a lookup function which, if it finds a
      * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
      * dentry into place and return that dentry rather than the passed one,
      * typically using d_splice_alias. */

#define DCACHE_REFERENCED	0x0040  /* Recently used, don't discard. */
#define DCACHE_RCUACCESS	0x0080	/* Entry has ever been RCU-visible */

#define DCACHE_CANT_MOUNT	0x0100
#define DCACHE_GENOCIDE		0x0200
#define DCACHE_SHRINK_LIST	0x0400

#define DCACHE_OP_WEAK_REVALIDATE	0x0800

#define DCACHE_NFSFS_RENAMED	0x1000
     /* this dentry has been "silly renamed" and has to be deleted on the last
      * dput() */
#define DCACHE_COOKIE		0x2000	/* For use by dcookie subsystem */
#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
     /* Parent inode is watched by some fsnotify listener */

#define DCACHE_MOUNTED		0x10000	/* is a mountpoint */
#define DCACHE_NEED_AUTOMOUNT	0x20000	/* handle automount on this dir */
#define DCACHE_MANAGE_TRANSIT	0x40000	/* manage transit from this dirent */
#define DCACHE_MANAGED_DENTRY \
	(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)

#define DCACHE_LRU_LIST		0x80000
#define DCACHE_DENTRY_KILLED	0x100000

extern seqlock_t rename_lock;

static inline int dname_external(const struct dentry *dentry)
{
	return dentry->d_name.name != dentry->d_iname;
}

/*
 * These are the low-level FS interfaces to the dcache..
 */
extern void d_instantiate(struct dentry *, struct inode *);
extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *);
extern struct dentry * d_materialise_unique(struct dentry *, struct inode *);
extern void __d_drop(struct dentry *dentry);
extern void d_drop(struct dentry *dentry);
extern void d_delete(struct dentry *);
extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op);

/* allocate/de-allocate */
extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
extern struct dentry *d_find_any_alias(struct inode *inode);
extern struct dentry * d_obtain_alias(struct inode *);
extern void shrink_dcache_sb(struct super_block *);
extern void shrink_dcache_parent(struct dentry *);
extern void shrink_dcache_for_umount(struct super_block *);
extern int d_invalidate(struct dentry *);

/* only used at mount-time */
extern struct dentry * d_make_root(struct inode *);

/* <clickety>-<click> the ramfs-type tree */
extern void d_genocide(struct dentry *);

extern void d_tmpfile(struct dentry *, struct inode *);

extern struct dentry *d_find_alias(struct inode *);
extern void d_prune_aliases(struct inode *);

/* test whether we have any submounts in a subdir tree */
extern int have_submounts(struct dentry *);
extern int check_submounts_and_drop(struct dentry *);

/*
 * This adds the entry to the hash queues.
 */
extern void d_rehash(struct dentry *);

/**
 * d_add - add dentry to hash queues
 * @entry: dentry to add
 * @inode: The inode to attach to this dentry
 *
 * This adds the entry to the hash queues and initializes @inode.
 * The entry was actually filled in earlier during d_alloc().
 */
 
static inline void d_add(struct dentry *entry, struct inode *inode)
{
	d_instantiate(entry, inode);
	d_rehash(entry);
}

/**
 * d_add_unique - add dentry to hash queues without aliasing
 * @entry: dentry to add
 * @inode: The inode to attach to this dentry
 *
 * This adds the entry to the hash queues and initializes @inode.
 * The entry was actually filled in earlier during d_alloc().
 */
static inline struct dentry *d_add_unique(struct dentry *entry, struct inode *inode)
{
	struct dentry *res;

	res = d_instantiate_unique(entry, inode);
	d_rehash(res != NULL ? res : entry);
	return res;
}

extern void dentry_update_name_case(struct dentry *, struct qstr *);

/* used for rename() and baskets */
extern void d_move(struct dentry *, struct dentry *);
extern struct dentry *d_ancestor(struct dentry *, struct dentry *);

/* appendix may either be NULL or be used for transname suffixes */
extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
				const struct qstr *name, unsigned *seq);

static inline unsigned d_count(const struct dentry *dentry)
{
	return dentry->d_lockref.count;
}

/* validate "insecure" dentry pointer */
extern int d_validate(struct dentry *, struct dentry *);

/*
 * helper function for dentry_operations.d_dname() members
 */
extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
extern char *simple_dname(struct dentry *, char *, int);

extern char *__d_path(const struct path *, const struct path *, char *, int);
extern char *d_absolute_path(const struct path *, char *, int);
extern char *d_path(const struct path *, char *, int);
extern char *dentry_path_raw(struct dentry *, char *, int);
extern char *dentry_path(struct dentry *, char *, int);

/* Allocation counts.. */

/**
 *	dget, dget_dlock -	get a reference to a dentry
 *	@dentry: dentry to get a reference to
 *
 *	Given a dentry or %NULL pointer increment the reference count
 *	if appropriate and return the dentry. A dentry will not be 
 *	destroyed when it has references.
 */
static inline struct dentry *dget_dlock(struct dentry *dentry)
{
	if (dentry)
		dentry->d_lockref.count++;
	return dentry;
}

static inline struct dentry *dget(struct dentry *dentry)
{
	if (dentry)
		lockref_get(&dentry->d_lockref);
	return dentry;
}

extern struct dentry *dget_parent(struct dentry *dentry);

/**
 *	d_unhashed -	is dentry hashed
 *	@dentry: entry to check
 *
 *	Returns true if the dentry passed is not currently hashed.
 */
 
static inline int d_unhashed(const struct dentry *dentry)
{
	return hlist_bl_unhashed(&dentry->d_hash);
}

static inline int d_unlinked(const struct dentry *dentry)
{
	return d_unhashed(dentry) && !IS_ROOT(dentry);
}

static inline int cant_mount(const struct dentry *dentry)
{
	return (dentry->d_flags & DCACHE_CANT_MOUNT);
}

static inline void dont_mount(struct dentry *dentry)
{
	spin_lock(&dentry->d_lock);
	dentry->d_flags |= DCACHE_CANT_MOUNT;
	spin_unlock(&dentry->d_lock);
}

extern void dput(struct dentry *);

static inline bool d_managed(const struct dentry *dentry)
{
	return dentry->d_flags & DCACHE_MANAGED_DENTRY;
}

static inline bool d_mountpoint(const struct dentry *dentry)
{
	return dentry->d_flags & DCACHE_MOUNTED;
}

extern int sysctl_vfs_cache_pressure;

static inline unsigned long vfs_pressure_ratio(unsigned long val)
{
	return mult_frac(val, sysctl_vfs_cache_pressure, 100);
}
#endif	/* __LINUX_DCACHE_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef __LINUX_DCACHE_H
	2	#define __LINUX_DCACHE_H
	3
60063497	4	#include <linux/atomic.h>
1da177e4	5	#include <linux/list.h>
82524746	6	#include <linux/rculist.h>
ceb5bdc2	7	#include <linux/rculist_bl.h>
1da177e4	8	#include <linux/spinlock.h>
31e6b01f	9	#include <linux/seqlock.h>
1da177e4 LT	10	#include <linux/cache.h>
1da177e4 LT	11	#include <linux/rcupdate.h>
98474236	12	#include <linux/lockref.h>
1da177e4 LT	13
1da177e4 LT	14	struct nameidata;
cf28b486	15	struct path;
1da177e4 LT	16	struct vfsmount;
	17
	18	/*
	19	* linux/include/linux/dcache.h
	20	*
	21	* Dirent cache data structures
	22	*
	23	* (C) Copyright 1997 Thomas Schoebel-Theuer,
	24	* with heavy changes by Linus Torvalds
	25	*/
	26
	27	#define IS_ROOT(x) ((x) == (x)->d_parent)
	28
26fe5750 LT	29	/* The hash is always the low bits of hash_len */
	30	#ifdef __LITTLE_ENDIAN
	31	#define HASH_LEN_DECLARE u32 hash; u32 len;
	32	#else
	33	#define HASH_LEN_DECLARE u32 len; u32 hash;
	34	#endif
	35
1da177e4 LT	36	/*
	37	* "quick string" -- eases parameter passing, but more importantly
	38	* saves "metadata" about the string (ie length and the hash).
	39	*
	40	* hash comes first so it snuggles against d_parent in the
	41	* dentry.
	42	*/
	43	struct qstr {
26fe5750 LT	44	union {
	45	struct {
	46	HASH_LEN_DECLARE;
	47	};
	48	u64 hash_len;
	49	};
1da177e4 LT	50	const unsigned char *name;
	51	};
	52
26fe5750 LT	53	#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
	54	#define hashlen_hash(hashlen) ((u32) (hashlen))
	55	#define hashlen_len(hashlen) ((u32)((hashlen) >> 32))
	56
1da177e4	57	struct dentry_stat_t {
3942c07c GC	58	long nr_dentry;
	59	long nr_unused;
	60	long age_limit; /* age in seconds */
	61	long want_pages; /* pages requested by system */
	62	long dummy[2];
1da177e4 LT	63	};
	64	extern struct dentry_stat_t dentry_stat;
	65
	66	/* Name hashing routines. Initial hash value */
	67	/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
	68	#define init_name_hash() 0
	69
	70	/* partial hash update function. Assume roughly 4 bits per character */
	71	static inline unsigned long
	72	partial_name_hash(unsigned long c, unsigned long prevhash)
	73	{
	74	return (prevhash + (c << 4) + (c >> 4)) * 11;
	75	}
	76
	77	/*
	78	* Finally: cut down the number of bits to a int value (and try to avoid
	79	* losing bits)
	80	*/
	81	static inline unsigned long end_name_hash(unsigned long hash)
	82	{
	83	return (unsigned int) hash;
	84	}
	85
	86	/* Compute the hash for a name string. */
0145acc2	87	extern unsigned int full_name_hash(const unsigned char *, unsigned int);
1da177e4	88
c2452f32 NP	89	/*
	90	* Try to keep struct dentry aligned on 64 byte cachelines (this will
	91	* give reasonable cacheline footprint with larger lines without the
	92	* large memory footprint increase).
	93	*/
	94	#ifdef CONFIG_64BIT
44a7d7a8	95	# define DNAME_INLINE_LEN 32 /* 192 bytes */
c2452f32	96	#else
44a7d7a8 NP	97	# ifdef CONFIG_SMP
	98	# define DNAME_INLINE_LEN 36 /* 128 bytes */
	99	# else
	100	# define DNAME_INLINE_LEN 40 /* 128 bytes */
	101	# endif
c2452f32	102	#endif
1da177e4	103
98474236 WL	104	#define d_lock d_lockref.lock
98474236 WL	105
1da177e4	106	struct dentry {
44a7d7a8	107	/* RCU lookup touched fields */
1da177e4	108	unsigned int d_flags; /* protected by d_lock */
31e6b01f	109	seqcount_t d_seq; /* per dentry seqlock */
ceb5bdc2	110	struct hlist_bl_node d_hash; /* lookup hash list */
1da177e4 LT	111	struct dentry d_parent; / parent directory */
1da177e4 LT	112	struct qstr d_name;
44a7d7a8 NP	113	struct inode d_inode; / Where the name belongs to - NULL is
	114	* negative */
	115	unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
	116
	117	/* Ref lookup also touches following */
98474236	118	struct lockref d_lockref; /* per-dentry lock and refcount */
44a7d7a8 NP	119	const struct dentry_operations *d_op;
	120	struct super_block d_sb; / The root of the dentry tree */
	121	unsigned long d_time; /* used by d_revalidate */
	122	void d_fsdata; / fs-specific data */
1da177e4 LT	123
1da177e4 LT	124	struct list_head d_lru; /* LRU list */
5160ee6f ED	125	/*
	126	* d_child and d_rcu can share memory
	127	*/
	128	union {
	129	struct list_head d_child; /* child of parent list */
	130	struct rcu_head d_rcu;
	131	} d_u;
1da177e4	132	struct list_head d_subdirs; /* our children */
b3d9b7a3	133	struct hlist_node d_alias; /* inode alias list */
1da177e4 LT	134	};
1da177e4 LT	135
a90b9c05 IM	136	/*
	137	* dentry->d_lock spinlock nesting subclasses:
	138	*
	139	* 0: normal
	140	* 1: nested
	141	*/
	142	enum dentry_d_lock_class
	143	{
	144	DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
	145	DENTRY_D_LOCK_NESTED
	146	};
	147
1da177e4	148	struct dentry_operations {
0b728e19	149	int (d_revalidate)(struct dentry , unsigned int);
ecf3d1f1	150	int (d_weak_revalidate)(struct dentry , unsigned int);
da53be12 LT	151	int (d_hash)(const struct dentry , struct qstr *);
da53be12 LT	152	int (d_compare)(const struct dentry , const struct dentry *,
621e155a	153	unsigned int, const char , const struct qstr );
fe15ce44	154	int (d_delete)(const struct dentry );
1da177e4	155	void (d_release)(struct dentry );
f0023bc6	156	void (d_prune)(struct dentry );
1da177e4	157	void (d_iput)(struct dentry , struct inode *);
c23fbb6b	158	char (d_dname)(struct dentry , char , int);
9875cf80	159	struct vfsmount (d_automount)(struct path *);
1aed3e42	160	int (d_manage)(struct dentry , bool);
44a7d7a8	161	} ____cacheline_aligned;
1da177e4	162
5eef7fa9 NP	163	/*
	164	* Locking rules for dentry_operations callbacks are to be found in
	165	* Documentation/filesystems/Locking. Keep it updated!
	166	*
621e155a NP	167	* FUrther descriptions are found in Documentation/filesystems/vfs.txt.
621e155a NP	168	* Keep it updated too!
1da177e4 LT	169	*/
	170
	171	/* d_flags entries */
830c0f0e LT	172	#define DCACHE_OP_HASH 0x0001
	173	#define DCACHE_OP_COMPARE 0x0002
	174	#define DCACHE_OP_REVALIDATE 0x0004
	175	#define DCACHE_OP_DELETE 0x0008
f0023bc6	176	#define DCACHE_OP_PRUNE 0x0010
5f57cbcc	177
f0023bc6	178	#define DCACHE_DISCONNECTED 0x0020
5f57cbcc NP	179	/* This dentry is possibly not currently connected to the dcache tree, in
	180	* which case its parent will either be itself, or will have this flag as
	181	* well. nfsd will not use a dentry with this bit set, but will first
	182	* endeavour to clear the bit either by discovering that it is connected,
	183	* or by performing lookup operations. Any filesystem which supports
	184	* nfsd_operations MUST have a lookup function which, if it finds a
	185	* directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
	186	* dentry into place and return that dentry rather than the passed one,
	187	* typically using d_splice_alias. */
1da177e4	188
f0023bc6 SW	189	#define DCACHE_REFERENCED 0x0040 /* Recently used, don't discard. */
f0023bc6 SW	190	#define DCACHE_RCUACCESS 0x0080 /* Entry has ever been RCU-visible */
c28f7e56	191
d83c49f3	192	#define DCACHE_CANT_MOUNT 0x0100
949854d0	193	#define DCACHE_GENOCIDE 0x0200
eaf5f907	194	#define DCACHE_SHRINK_LIST 0x0400
5f57cbcc	195
ecf3d1f1 JL	196	#define DCACHE_OP_WEAK_REVALIDATE 0x0800
ecf3d1f1 JL	197
830c0f0e LT	198	#define DCACHE_NFSFS_RENAMED 0x1000
	199	/* this dentry has been "silly renamed" and has to be deleted on the last
	200	* dput() */
	201	#define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */
	202	#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
	203	/* Parent inode is watched by some fsnotify listener */
fb045adb	204
9875cf80 DH	205	#define DCACHE_MOUNTED 0x10000 /* is a mountpoint */
9875cf80 DH	206	#define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */
cc53ce53	207	#define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */
9875cf80	208	#define DCACHE_MANAGED_DENTRY \
cc53ce53	209	(DCACHE_MOUNTED\|DCACHE_NEED_AUTOMOUNT\|DCACHE_MANAGE_TRANSIT)
9875cf80	210
8aab6a27	211	#define DCACHE_LRU_LIST 0x80000
b161dfa6 MS	212	#define DCACHE_DENTRY_KILLED 0x100000
b161dfa6 MS	213
74c3cbe3	214	extern seqlock_t rename_lock;
1da177e4	215
f0d3b3de	216	static inline int dname_external(const struct dentry *dentry)
1da177e4 LT	217	{
	218	return dentry->d_name.name != dentry->d_iname;
	219	}
	220
	221	/*
	222	* These are the low-level FS interfaces to the dcache..
	223	*/
	224	extern void d_instantiate(struct dentry , struct inode );
	225	extern struct dentry * d_instantiate_unique(struct dentry , struct inode );
770bfad8	226	extern struct dentry * d_materialise_unique(struct dentry , struct inode );
789680d1 NP	227	extern void __d_drop(struct dentry *dentry);
789680d1 NP	228	extern void d_drop(struct dentry *dentry);
1da177e4	229	extern void d_delete(struct dentry *);
fb045adb	230	extern void d_set_d_op(struct dentry dentry, const struct dentry_operations op);
1da177e4 LT	231
	232	/* allocate/de-allocate */
	233	extern struct dentry * d_alloc(struct dentry , const struct qstr );
4b936885	234	extern struct dentry * d_alloc_pseudo(struct super_block , const struct qstr );
1da177e4	235	extern struct dentry * d_splice_alias(struct inode , struct dentry );
e45b590b	236	extern struct dentry * d_add_ci(struct dentry , struct inode , struct qstr *);
46f72b34	237	extern struct dentry d_find_any_alias(struct inode inode);
4ea3ada2	238	extern struct dentry * d_obtain_alias(struct inode *);
1da177e4 LT	239	extern void shrink_dcache_sb(struct super_block *);
1da177e4 LT	240	extern void shrink_dcache_parent(struct dentry *);
c636ebdb	241	extern void shrink_dcache_for_umount(struct super_block *);
1da177e4 LT	242	extern int d_invalidate(struct dentry *);
	243
	244	/* only used at mount-time */
adc0e91a	245	extern struct dentry * d_make_root(struct inode *);
1da177e4 LT	246
	247	/* <clickety>-<click> the ramfs-type tree */
	248	extern void d_genocide(struct dentry *);
	249
60545d0d AV	250	extern void d_tmpfile(struct dentry , struct inode );
60545d0d AV	251
1da177e4 LT	252	extern struct dentry d_find_alias(struct inode );
	253	extern void d_prune_aliases(struct inode *);
	254
	255	/* test whether we have any submounts in a subdir tree */
	256	extern int have_submounts(struct dentry *);
848ac114	257	extern int check_submounts_and_drop(struct dentry *);
1da177e4 LT	258
	259	/*
	260	* This adds the entry to the hash queues.
	261	*/
	262	extern void d_rehash(struct dentry *);
	263
	264	/**
	265	* d_add - add dentry to hash queues
	266	* @entry: dentry to add
	267	* @inode: The inode to attach to this dentry
	268	*
	269	* This adds the entry to the hash queues and initializes @inode.
	270	* The entry was actually filled in earlier during d_alloc().
	271	*/
	272
	273	static inline void d_add(struct dentry entry, struct inode inode)
	274	{
	275	d_instantiate(entry, inode);
	276	d_rehash(entry);
	277	}
	278
	279	/**
	280	* d_add_unique - add dentry to hash queues without aliasing
	281	* @entry: dentry to add
	282	* @inode: The inode to attach to this dentry
	283	*
	284	* This adds the entry to the hash queues and initializes @inode.
	285	* The entry was actually filled in earlier during d_alloc().
	286	*/
	287	static inline struct dentry d_add_unique(struct dentry entry, struct inode *inode)
	288	{
	289	struct dentry *res;
	290
	291	res = d_instantiate_unique(entry, inode);
	292	d_rehash(res != NULL ? res : entry);
	293	return res;
	294	}
	295
fb2d5b86 NP	296	extern void dentry_update_name_case(struct dentry , struct qstr );
fb2d5b86 NP	297
1da177e4 LT	298	/* used for rename() and baskets */
1da177e4 LT	299	extern void d_move(struct dentry , struct dentry );
e2761a11	300	extern struct dentry d_ancestor(struct dentry , struct dentry *);
1da177e4 LT	301
1da177e4 LT	302	/* appendix may either be NULL or be used for transname suffixes */
da2d8455	303	extern struct dentry d_lookup(const struct dentry , const struct qstr *);
31e6b01f	304	extern struct dentry d_hash_and_lookup(struct dentry , struct qstr *);
a713ca2a	305	extern struct dentry __d_lookup(const struct dentry , const struct qstr *);
8966be90	306	extern struct dentry __d_lookup_rcu(const struct dentry parent,
da53be12	307	const struct qstr name, unsigned seq);
31e6b01f	308
24924a20	309	static inline unsigned d_count(const struct dentry *dentry)
84d08fa8	310	{
98474236	311	return dentry->d_lockref.count;
84d08fa8 AV	312	}
84d08fa8 AV	313
1da177e4 LT	314	/* validate "insecure" dentry pointer */
	315	extern int d_validate(struct dentry , struct dentry );
	316
c23fbb6b ED	317	/*
	318	* helper function for dentry_operations.d_dname() members
	319	*/
	320	extern char dynamic_dname(struct dentry , char , int, const char , ...);
118b2302	321	extern char simple_dname(struct dentry , char *, int);
c23fbb6b	322
02125a82 AV	323	extern char __d_path(const struct path , const struct path , char , int);
02125a82 AV	324	extern char d_absolute_path(const struct path , char *, int);
20d4fdc1	325	extern char d_path(const struct path , char *, int);
ec2447c2	326	extern char dentry_path_raw(struct dentry , char *, int);
6092d048	327	extern char dentry_path(struct dentry , char *, int);
cf28b486	328
1da177e4 LT	329	/* Allocation counts.. */
	330
	331	/**
dc0474be	332	* dget, dget_dlock - get a reference to a dentry
1da177e4 LT	333	* @dentry: dentry to get a reference to
	334	*
	335	* Given a dentry or %NULL pointer increment the reference count
	336	* if appropriate and return the dentry. A dentry will not be
dc0474be	337	* destroyed when it has references.
1da177e4	338	*/
b7ab39f6 NP	339	static inline struct dentry dget_dlock(struct dentry dentry)
b7ab39f6 NP	340	{
dc0474be	341	if (dentry)
98474236	342	dentry->d_lockref.count++;
b7ab39f6 NP	343	return dentry;
b7ab39f6 NP	344	}
2fd6b7f5	345
1da177e4 LT	346	static inline struct dentry dget(struct dentry dentry)
1da177e4 LT	347	{
98474236 WL	348	if (dentry)
98474236 WL	349	lockref_get(&dentry->d_lockref);
1da177e4 LT	350	return dentry;
	351	}
	352
b7ab39f6	353	extern struct dentry dget_parent(struct dentry dentry);
1da177e4 LT	354
	355	/**
	356	* d_unhashed - is dentry hashed
	357	* @dentry: entry to check
	358	*
	359	* Returns true if the dentry passed is not currently hashed.
	360	*/
	361
f0d3b3de	362	static inline int d_unhashed(const struct dentry *dentry)
1da177e4	363	{
dea3667b	364	return hlist_bl_unhashed(&dentry->d_hash);
1da177e4 LT	365	}
1da177e4 LT	366
f0d3b3de	367	static inline int d_unlinked(const struct dentry *dentry)
f3da392e AD	368	{
	369	return d_unhashed(dentry) && !IS_ROOT(dentry);
	370	}
	371
f0d3b3de	372	static inline int cant_mount(const struct dentry *dentry)
d83c49f3 AV	373	{
	374	return (dentry->d_flags & DCACHE_CANT_MOUNT);
	375	}
	376
	377	static inline void dont_mount(struct dentry *dentry)
	378	{
	379	spin_lock(&dentry->d_lock);
	380	dentry->d_flags \|= DCACHE_CANT_MOUNT;
	381	spin_unlock(&dentry->d_lock);
	382	}
	383
1da177e4 LT	384	extern void dput(struct dentry *);
1da177e4 LT	385
f0d3b3de	386	static inline bool d_managed(const struct dentry *dentry)
cc53ce53 DH	387	{
	388	return dentry->d_flags & DCACHE_MANAGED_DENTRY;
	389	}
	390
f0d3b3de	391	static inline bool d_mountpoint(const struct dentry *dentry)
1da177e4	392	{
5f57cbcc	393	return dentry->d_flags & DCACHE_MOUNTED;
1da177e4 LT	394	}
1da177e4 LT	395
1da177e4 LT	396	extern int sysctl_vfs_cache_pressure;
1da177e4 LT	397
55f841ce GC	398	static inline unsigned long vfs_pressure_ratio(unsigned long val)
	399	{
	400	return mult_frac(val, sysctl_vfs_cache_pressure, 100);
	401	}
1da177e4	402	#endif /* __LINUX_DCACHE_H */