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

#ifndef __LINUX_DCACHE_H
#define __LINUX_DCACHE_H

#include <asm/atomic.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/rcupdate.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)

/*
 * "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 {
	unsigned int hash;
	unsigned int len;
	const unsigned char *name;
};

struct dentry_stat_t {
	int nr_dentry;
	int nr_unused;
	int age_limit;          /* age in seconds */
	int want_pages;         /* pages requested by system */
	int 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. */
static inline unsigned int
full_name_hash(const unsigned char *name, unsigned int len)
{
	unsigned long hash = init_name_hash();
	while (len--)
		hash = partial_name_hash(*name++, hash);
	return end_name_hash(hash);
}

struct dcookie_struct;

#define DNAME_INLINE_LEN_MIN 36

struct dentry {
	atomic_t d_count;
	unsigned int d_flags;		/* protected by d_lock */
	spinlock_t d_lock;		/* per dentry lock */
	struct inode *d_inode;		/* Where the name belongs to - NULL is
					 * negative */
	/*
	 * The next three fields are touched by __d_lookup.  Place them here
	 * so they all fit in a cache line.
	 */
	struct hlist_node d_hash;	/* lookup hash list */
	struct dentry *d_parent;	/* parent directory */
	struct qstr d_name;

	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 list_head d_alias;	/* inode alias list */
	unsigned long d_time;		/* used by d_revalidate */
	struct dentry_operations *d_op;
	struct super_block *d_sb;	/* The root of the dentry tree */
	void *d_fsdata;			/* fs-specific data */
#ifdef CONFIG_PROFILING
	struct dcookie_struct *d_cookie; /* cookie, if any */
#endif
	int d_mounted;
	unsigned char d_iname[DNAME_INLINE_LEN_MIN];	/* small names */
};

/*
 * 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 *, struct nameidata *);
	int (*d_hash) (struct dentry *, struct qstr *);
	int (*d_compare) (struct dentry *, struct qstr *, struct qstr *);
	int (*d_delete)(struct dentry *);
	void (*d_release)(struct dentry *);
	void (*d_iput)(struct dentry *, struct inode *);
	char *(*d_dname)(struct dentry *, char *, int);
};

/* the dentry parameter passed to d_hash and d_compare is the parent
 * directory of the entries to be compared. It is used in case these
 * functions need any directory specific information for determining
 * equivalency classes.  Using the dentry itself might not work, as it
 * might be a negative dentry which has no information associated with
 * it */

/*
locking rules:
		big lock	dcache_lock	d_lock   may block
d_revalidate:	no		no		no       yes
d_hash		no		no		no       yes
d_compare:	no		yes		yes      no
d_delete:	no		yes		no       no
d_release:	no		no		no       yes
d_iput:		no		no		no       yes
 */

/* d_flags entries */
#define DCACHE_AUTOFS_PENDING 0x0001    /* autofs: "under construction" */
#define DCACHE_NFSFS_RENAMED  0x0002    /* this dentry has been "silly
					 * renamed" and has to be
					 * deleted on the last dput()
					 */
#define	DCACHE_DISCONNECTED 0x0004
     /* 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	0x0008  /* Recently used, don't discard. */
#define DCACHE_UNHASHED		0x0010	

#define DCACHE_INOTIFY_PARENT_WATCHED	0x0020 /* Parent inode is watched */

extern spinlock_t dcache_lock;
extern seqlock_t rename_lock;

/**
 * d_drop - drop a dentry
 * @dentry: dentry to drop
 *
 * d_drop() unhashes the entry from the parent dentry hashes, so that it won't
 * be found through a VFS lookup any more. Note that this is different from
 * deleting the dentry - d_delete will try to mark the dentry negative if
 * possible, giving a successful _negative_ lookup, while d_drop will
 * just make the cache lookup fail.
 *
 * d_drop() is used mainly for stuff that wants to invalidate a dentry for some
 * reason (NFS timeouts or autofs deletes).
 *
 * __d_drop requires dentry->d_lock.
 */

static inline void __d_drop(struct dentry *dentry)
{
	if (!(dentry->d_flags & DCACHE_UNHASHED)) {
		dentry->d_flags |= DCACHE_UNHASHED;
		hlist_del_rcu(&dentry->d_hash);
	}
}

static inline void d_drop(struct dentry *dentry)
{
	spin_lock(&dcache_lock);
	spin_lock(&dentry->d_lock);
 	__d_drop(dentry);
	spin_unlock(&dentry->d_lock);
	spin_unlock(&dcache_lock);
}

static inline int dname_external(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_delete(struct dentry *);

/* allocate/de-allocate */
extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
extern struct dentry * d_alloc_anon(struct inode *);
extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
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_alloc_root(struct inode *);

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

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 *);

/*
 * 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;
}

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

/* appendix may either be NULL or be used for transname suffixes */
extern struct dentry * d_lookup(struct dentry *, struct qstr *);
extern struct dentry * __d_lookup(struct dentry *, struct qstr *);
extern struct dentry * d_hash_and_lookup(struct dentry *, struct qstr *);

/* 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 *__d_path(const struct path *path, struct path *root, char *, int);
extern char *d_path(struct path *, char *, int);
extern char *dentry_path(struct dentry *, char *, int);

/* Allocation counts.. */

/**
 *	dget, dget_locked	-	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. dget() should never be
 *	called for dentries with zero reference counter. For these cases
 *	(preferably none, functions in dcache.c are sufficient for normal
 *	needs and they take necessary precautions) you should hold dcache_lock
 *	and call dget_locked() instead of dget().
 */
 
static inline struct dentry *dget(struct dentry *dentry)
{
	if (dentry) {
		BUG_ON(!atomic_read(&dentry->d_count));
		atomic_inc(&dentry->d_count);
	}
	return dentry;
}

extern struct dentry * dget_locked(struct 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(struct dentry *dentry)
{
	return (dentry->d_flags & DCACHE_UNHASHED);
}

static inline struct dentry *dget_parent(struct dentry *dentry)
{
	struct dentry *ret;

	spin_lock(&dentry->d_lock);
	ret = dget(dentry->d_parent);
	spin_unlock(&dentry->d_lock);
	return ret;
}

extern void dput(struct dentry *);

static inline int d_mountpoint(struct dentry *dentry)
{
	return dentry->d_mounted;
}

extern struct vfsmount *lookup_mnt(struct vfsmount *, struct dentry *);
extern struct dentry *lookup_create(struct nameidata *nd, int is_dir);

extern int sysctl_vfs_cache_pressure;

#endif	/* __LINUX_DCACHE_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef __LINUX_DCACHE_H
	2	#define __LINUX_DCACHE_H
	3
1da177e4 LT	4	#include <asm/atomic.h>
	5	#include <linux/list.h>
	6	#include <linux/spinlock.h>
	7	#include <linux/cache.h>
	8	#include <linux/rcupdate.h>
1da177e4 LT	9
1da177e4 LT	10	struct nameidata;
cf28b486	11	struct path;
1da177e4 LT	12	struct vfsmount;
	13
	14	/*
	15	* linux/include/linux/dcache.h
	16	*
	17	* Dirent cache data structures
	18	*
	19	* (C) Copyright 1997 Thomas Schoebel-Theuer,
	20	* with heavy changes by Linus Torvalds
	21	*/
	22
	23	#define IS_ROOT(x) ((x) == (x)->d_parent)
	24
	25	/*
	26	* "quick string" -- eases parameter passing, but more importantly
	27	* saves "metadata" about the string (ie length and the hash).
	28	*
	29	* hash comes first so it snuggles against d_parent in the
	30	* dentry.
	31	*/
	32	struct qstr {
	33	unsigned int hash;
	34	unsigned int len;
	35	const unsigned char *name;
	36	};
	37
	38	struct dentry_stat_t {
	39	int nr_dentry;
	40	int nr_unused;
	41	int age_limit; /* age in seconds */
	42	int want_pages; /* pages requested by system */
	43	int dummy[2];
	44	};
	45	extern struct dentry_stat_t dentry_stat;
	46
	47	/* Name hashing routines. Initial hash value */
	48	/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
	49	#define init_name_hash() 0
	50
	51	/* partial hash update function. Assume roughly 4 bits per character */
	52	static inline unsigned long
	53	partial_name_hash(unsigned long c, unsigned long prevhash)
	54	{
	55	return (prevhash + (c << 4) + (c >> 4)) * 11;
	56	}
	57
	58	/*
	59	* Finally: cut down the number of bits to a int value (and try to avoid
	60	* losing bits)
	61	*/
	62	static inline unsigned long end_name_hash(unsigned long hash)
	63	{
	64	return (unsigned int) hash;
	65	}
	66
	67	/* Compute the hash for a name string. */
	68	static inline unsigned int
	69	full_name_hash(const unsigned char *name, unsigned int len)
	70	{
	71	unsigned long hash = init_name_hash();
	72	while (len--)
	73	hash = partial_name_hash(*name++, hash);
	74	return end_name_hash(hash);
	75	}
76
77	struct dcookie_struct;
78
79	#define DNAME_INLINE_LEN_MIN 36
80
81	struct dentry {
82	atomic_t d_count;
83	unsigned int d_flags; /* protected by d_lock */
84	spinlock_t d_lock; /* per dentry lock */
85	struct inode d_inode; / Where the name belongs to - NULL is
86	* negative */
87	/*
88	* The next three fields are touched by __d_lookup. Place them here
3f4bb1f4	89	* so they all fit in a cache line.
1da177e4	90	*/
3f4bb1f4	91	struct hlist_node d_hash; /* lookup hash list */
1da177e4 LT	92	struct dentry d_parent; / parent directory */
	93	struct qstr d_name;
	94
	95	struct list_head d_lru; /* LRU list */
5160ee6f ED	96	/*
	97	* d_child and d_rcu can share memory
	98	*/
	99	union {
	100	struct list_head d_child; /* child of parent list */
	101	struct rcu_head d_rcu;
	102	} d_u;
1da177e4 LT	103	struct list_head d_subdirs; /* our children */
	104	struct list_head d_alias; /* inode alias list */
	105	unsigned long d_time; /* used by d_revalidate */
	106	struct dentry_operations *d_op;
	107	struct super_block d_sb; / The root of the dentry tree */
	108	void d_fsdata; / fs-specific data */
47ba87e0	109	#ifdef CONFIG_PROFILING
1da177e4	110	struct dcookie_struct d_cookie; / cookie, if any */
47ba87e0	111	#endif
1da177e4 LT	112	int d_mounted;
	113	unsigned char d_iname[DNAME_INLINE_LEN_MIN]; /* small names */
	114	};
	115
a90b9c05 IM	116	/*
	117	* dentry->d_lock spinlock nesting subclasses:
	118	*
	119	* 0: normal
	120	* 1: nested
	121	*/
	122	enum dentry_d_lock_class
	123	{
	124	DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
	125	DENTRY_D_LOCK_NESTED
	126	};
	127
1da177e4 LT	128	struct dentry_operations {
	129	int (d_revalidate)(struct dentry , struct nameidata *);
	130	int (d_hash) (struct dentry , struct qstr *);
	131	int (d_compare) (struct dentry , struct qstr , struct qstr );
	132	int (d_delete)(struct dentry );
	133	void (d_release)(struct dentry );
	134	void (d_iput)(struct dentry , struct inode *);
c23fbb6b	135	char (d_dname)(struct dentry , char , int);
1da177e4 LT	136	};
	137
	138	/* the dentry parameter passed to d_hash and d_compare is the parent
	139	* directory of the entries to be compared. It is used in case these
	140	* functions need any directory specific information for determining
	141	* equivalency classes. Using the dentry itself might not work, as it
	142	* might be a negative dentry which has no information associated with
	143	* it */
	144
	145	/*
	146	locking rules:
	147	big lock dcache_lock d_lock may block
	148	d_revalidate: no no no yes
	149	d_hash no no no yes
	150	d_compare: no yes yes no
	151	d_delete: no yes no no
	152	d_release: no no no yes
	153	d_iput: no no no yes
	154	*/
	155
	156	/* d_flags entries */
	157	#define DCACHE_AUTOFS_PENDING 0x0001 /* autofs: "under construction" */
	158	#define DCACHE_NFSFS_RENAMED 0x0002 /* this dentry has been "silly
	159	* renamed" and has to be
	160	* deleted on the last dput()
	161	*/
	162	#define DCACHE_DISCONNECTED 0x0004
	163	/* This dentry is possibly not currently connected to the dcache tree,
	164	* in which case its parent will either be itself, or will have this
	165	* flag as well. nfsd will not use a dentry with this bit set, but will
	166	* first endeavour to clear the bit either by discovering that it is
	167	* connected, or by performing lookup operations. Any filesystem which
	168	* supports nfsd_operations MUST have a lookup function which, if it finds
	169	* a directory inode with a DCACHE_DISCONNECTED dentry, will d_move
	170	* that dentry into place and return that dentry rather than the passed one,
	171	* typically using d_splice_alias.
	172	*/
	173
	174	#define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */
	175	#define DCACHE_UNHASHED 0x0010
	176
c32ccd87 NP	177	#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched */
c32ccd87 NP	178
1da177e4	179	extern spinlock_t dcache_lock;
74c3cbe3	180	extern seqlock_t rename_lock;
1da177e4 LT	181
	182	/**
	183	* d_drop - drop a dentry
	184	* @dentry: dentry to drop
	185	*
	186	* d_drop() unhashes the entry from the parent dentry hashes, so that it won't
	187	* be found through a VFS lookup any more. Note that this is different from
	188	* deleting the dentry - d_delete will try to mark the dentry negative if
	189	* possible, giving a successful _negative_ lookup, while d_drop will
	190	* just make the cache lookup fail.
	191	*
	192	* d_drop() is used mainly for stuff that wants to invalidate a dentry for some
	193	* reason (NFS timeouts or autofs deletes).
	194	*
	195	* __d_drop requires dentry->d_lock.
	196	*/
	197
	198	static inline void __d_drop(struct dentry *dentry)
	199	{
	200	if (!(dentry->d_flags & DCACHE_UNHASHED)) {
	201	dentry->d_flags \|= DCACHE_UNHASHED;
	202	hlist_del_rcu(&dentry->d_hash);
	203	}
	204	}
	205
	206	static inline void d_drop(struct dentry *dentry)
	207	{
	208	spin_lock(&dcache_lock);
	209	spin_lock(&dentry->d_lock);
	210	__d_drop(dentry);
	211	spin_unlock(&dentry->d_lock);
	212	spin_unlock(&dcache_lock);
	213	}
	214
	215	static inline int dname_external(struct dentry *dentry)
	216	{
	217	return dentry->d_name.name != dentry->d_iname;
	218	}
	219
	220	/*
	221	* These are the low-level FS interfaces to the dcache..
	222	*/
	223	extern void d_instantiate(struct dentry , struct inode );
	224	extern struct dentry * d_instantiate_unique(struct dentry , struct inode );
770bfad8	225	extern struct dentry * d_materialise_unique(struct dentry , struct inode );
1da177e4 LT	226	extern void d_delete(struct dentry *);
	227
	228	/* allocate/de-allocate */
	229	extern struct dentry * d_alloc(struct dentry , const struct qstr );
	230	extern struct dentry * d_alloc_anon(struct inode *);
	231	extern struct dentry * d_splice_alias(struct inode , struct dentry );
	232	extern void shrink_dcache_sb(struct super_block *);
	233	extern void shrink_dcache_parent(struct dentry *);
c636ebdb	234	extern void shrink_dcache_for_umount(struct super_block *);
1da177e4 LT	235	extern int d_invalidate(struct dentry *);
	236
	237	/* only used at mount-time */
	238	extern struct dentry * d_alloc_root(struct inode *);
	239
	240	/* <clickety>-<click> the ramfs-type tree */
	241	extern void d_genocide(struct dentry *);
	242
	243	extern struct dentry d_find_alias(struct inode );
	244	extern void d_prune_aliases(struct inode *);
	245
	246	/* test whether we have any submounts in a subdir tree */
	247	extern int have_submounts(struct dentry *);
	248
	249	/*
	250	* This adds the entry to the hash queues.
	251	*/
	252	extern void d_rehash(struct dentry *);
	253
	254	/**
	255	* d_add - add dentry to hash queues
	256	* @entry: dentry to add
	257	* @inode: The inode to attach to this dentry
	258	*
	259	* This adds the entry to the hash queues and initializes @inode.
	260	* The entry was actually filled in earlier during d_alloc().
	261	*/
	262
	263	static inline void d_add(struct dentry entry, struct inode inode)
	264	{
	265	d_instantiate(entry, inode);
	266	d_rehash(entry);
	267	}
	268
	269	/**
	270	* d_add_unique - add dentry to hash queues without aliasing
	271	* @entry: dentry to add
	272	* @inode: The inode to attach to this dentry
	273	*
	274	* This adds the entry to the hash queues and initializes @inode.
	275	* The entry was actually filled in earlier during d_alloc().
	276	*/
	277	static inline struct dentry d_add_unique(struct dentry entry, struct inode *inode)
	278	{
	279	struct dentry *res;
	280
	281	res = d_instantiate_unique(entry, inode);
	282	d_rehash(res != NULL ? res : entry);
	283	return res;
	284	}
	285
	286	/* used for rename() and baskets */
	287	extern void d_move(struct dentry , struct dentry );
	288
	289	/* appendix may either be NULL or be used for transname suffixes */
	290	extern struct dentry * d_lookup(struct dentry , struct qstr );
	291	extern struct dentry * __d_lookup(struct dentry , struct qstr );
3e7e241f	292	extern struct dentry * d_hash_and_lookup(struct dentry , struct qstr );
1da177e4 LT	293
	294	/* validate "insecure" dentry pointer */
	295	extern int d_validate(struct dentry , struct dentry );
	296
c23fbb6b ED	297	/*
	298	* helper function for dentry_operations.d_dname() members
	299	*/
	300	extern char dynamic_dname(struct dentry , char , int, const char , ...);
	301
9d1bc601	302	extern char __d_path(const struct path path, struct path root, char , int);
cf28b486	303	extern char d_path(struct path , char *, int);
6092d048	304	extern char dentry_path(struct dentry , char *, int);
cf28b486	305
1da177e4 LT	306	/* Allocation counts.. */
	307
	308	/**
	309	* dget, dget_locked - get a reference to a dentry
	310	* @dentry: dentry to get a reference to
	311	*
	312	* Given a dentry or %NULL pointer increment the reference count
	313	* if appropriate and return the dentry. A dentry will not be
	314	* destroyed when it has references. dget() should never be
	315	* called for dentries with zero reference counter. For these cases
	316	* (preferably none, functions in dcache.c are sufficient for normal
	317	* needs and they take necessary precautions) you should hold dcache_lock
	318	* and call dget_locked() instead of dget().
	319	*/
	320
	321	static inline struct dentry dget(struct dentry dentry)
	322	{
	323	if (dentry) {
	324	BUG_ON(!atomic_read(&dentry->d_count));
	325	atomic_inc(&dentry->d_count);
	326	}
	327	return dentry;
	328	}
	329
	330	extern struct dentry * dget_locked(struct dentry *);
	331
	332	/**
	333	* d_unhashed - is dentry hashed
	334	* @dentry: entry to check
	335	*
	336	* Returns true if the dentry passed is not currently hashed.
	337	*/
	338
	339	static inline int d_unhashed(struct dentry *dentry)
	340	{
	341	return (dentry->d_flags & DCACHE_UNHASHED);
	342	}
	343
	344	static inline struct dentry dget_parent(struct dentry dentry)
	345	{
	346	struct dentry *ret;
	347
	348	spin_lock(&dentry->d_lock);
	349	ret = dget(dentry->d_parent);
	350	spin_unlock(&dentry->d_lock);
	351	return ret;
	352	}
	353
	354	extern void dput(struct dentry *);
	355
	356	static inline int d_mountpoint(struct dentry *dentry)
	357	{
	358	return dentry->d_mounted;
	359	}
	360
	361	extern struct vfsmount lookup_mnt(struct vfsmount , struct dentry *);
	362	extern struct dentry lookup_create(struct nameidata nd, int is_dir);
	363
	364	extern int sysctl_vfs_cache_pressure;
	365
1da177e4	366	#endif /* __LINUX_DCACHE_H */