[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>

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;

/*
 * Compare 2 name strings, return 0 if they match, otherwise non-zero.
 * The strings are both count bytes long, and count is non-zero.
 */
static inline int dentry_cmp(const unsigned char *cs, size_t scount,
				const unsigned char *ct, size_t tcount)
{
	int ret;
	if (scount != tcount)
		return 1;
	do {
		ret = (*cs != *ct);
		if (ret)
			break;
		cs++;
		ct++;
		tcount--;
	} while (tcount);
	return ret;
}

/* 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);
}

/*
 * 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

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 */
	unsigned int d_count;		/* protected by d_lock */
	spinlock_t d_lock;		/* per dentry lock */
	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 list_head 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 *, struct nameidata *);
	int (*d_hash)(const struct dentry *, const struct inode *,
			struct qstr *);
	int (*d_compare)(const struct dentry *, const struct inode *,
			const struct dentry *, const struct inode *,
			unsigned int, const char *, const struct qstr *);
	int (*d_delete)(const struct dentry *);
	void (*d_release)(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_DISCONNECTED	0x0010
     /* 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	0x0020  /* Recently used, don't discard. */
#define DCACHE_RCUACCESS	0x0040	/* Entry has ever been RCU-visible */

#define DCACHE_CANT_MOUNT	0x0100
#define DCACHE_GENOCIDE		0x0200

#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_NEED_LOOKUP	0x80000 /* dentry requires i_op->lookup */
#define DCACHE_MANAGED_DENTRY \
	(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)

extern seqlock_t rename_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_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_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_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;
}

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(struct dentry *, struct qstr *);
extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
extern struct dentry *__d_lookup(struct dentry *, struct qstr *);
extern struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name,
				unsigned *seq, struct inode **inode);

/**
 * __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok
 * @dentry: dentry to take a ref on
 * @seq: seqcount to verify against
 * Returns: 0 on failure, else 1.
 *
 * __d_rcu_to_refcount operates on a dentry,seq pair that was returned
 * by __d_lookup_rcu, to get a reference on an rcu-walk dentry.
 */
static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq)
{
	int ret = 0;

	assert_spin_locked(&dentry->d_lock);
	if (!read_seqcount_retry(&dentry->d_seq, seq)) {
		ret = 1;
		dentry->d_count++;
	}

	return ret;
}

/* 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(const struct path *, char *, int);
extern char *d_path_with_unreachable(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_count++;
	return dentry;
}

static inline struct dentry *dget(struct dentry *dentry)
{
	if (dentry) {
		spin_lock(&dentry->d_lock);
		dget_dlock(dentry);
		spin_unlock(&dentry->d_lock);
	}
	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(struct dentry *dentry)
{
	return hlist_bl_unhashed(&dentry->d_hash);
}

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

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

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

static inline bool d_need_lookup(struct dentry *dentry)
{
	return dentry->d_flags & DCACHE_NEED_LOOKUP;
}

extern void d_clear_need_lookup(struct dentry *dentry);

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
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>
1da177e4 LT	12
1da177e4 LT	13	struct nameidata;
cf28b486	14	struct path;
1da177e4 LT	15	struct vfsmount;
	16
	17	/*
	18	* linux/include/linux/dcache.h
	19	*
	20	* Dirent cache data structures
	21	*
	22	* (C) Copyright 1997 Thomas Schoebel-Theuer,
	23	* with heavy changes by Linus Torvalds
	24	*/
	25
	26	#define IS_ROOT(x) ((x) == (x)->d_parent)
	27
	28	/*
	29	* "quick string" -- eases parameter passing, but more importantly
	30	* saves "metadata" about the string (ie length and the hash).
	31	*
	32	* hash comes first so it snuggles against d_parent in the
	33	* dentry.
	34	*/
	35	struct qstr {
	36	unsigned int hash;
	37	unsigned int len;
	38	const unsigned char *name;
	39	};
	40
	41	struct dentry_stat_t {
	42	int nr_dentry;
	43	int nr_unused;
	44	int age_limit; /* age in seconds */
	45	int want_pages; /* pages requested by system */
	46	int dummy[2];
	47	};
	48	extern struct dentry_stat_t dentry_stat;
	49
9d55c369 NP	50	/*
	51	* Compare 2 name strings, return 0 if they match, otherwise non-zero.
	52	* The strings are both count bytes long, and count is non-zero.
	53	*/
	54	static inline int dentry_cmp(const unsigned char *cs, size_t scount,
	55	const unsigned char *ct, size_t tcount)
	56	{
	57	int ret;
	58	if (scount != tcount)
	59	return 1;
	60	do {
	61	ret = (cs != ct);
	62	if (ret)
	63	break;
	64	cs++;
	65	ct++;
	66	tcount--;
	67	} while (tcount);
	68	return ret;
	69	}
	70
1da177e4 LT	71	/* Name hashing routines. Initial hash value */
	72	/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
	73	#define init_name_hash() 0
	74
	75	/* partial hash update function. Assume roughly 4 bits per character */
	76	static inline unsigned long
	77	partial_name_hash(unsigned long c, unsigned long prevhash)
	78	{
	79	return (prevhash + (c << 4) + (c >> 4)) * 11;
	80	}
	81
	82	/*
	83	* Finally: cut down the number of bits to a int value (and try to avoid
	84	* losing bits)
	85	*/
	86	static inline unsigned long end_name_hash(unsigned long hash)
	87	{
	88	return (unsigned int) hash;
	89	}
	90
	91	/* Compute the hash for a name string. */
	92	static inline unsigned int
	93	full_name_hash(const unsigned char *name, unsigned int len)
	94	{
	95	unsigned long hash = init_name_hash();
	96	while (len--)
	97	hash = partial_name_hash(*name++, hash);
	98	return end_name_hash(hash);
	99	}
	100
c2452f32 NP	101	/*
	102	* Try to keep struct dentry aligned on 64 byte cachelines (this will
	103	* give reasonable cacheline footprint with larger lines without the
	104	* large memory footprint increase).
	105	*/
	106	#ifdef CONFIG_64BIT
44a7d7a8	107	# define DNAME_INLINE_LEN 32 /* 192 bytes */
c2452f32	108	#else
44a7d7a8 NP	109	# ifdef CONFIG_SMP
	110	# define DNAME_INLINE_LEN 36 /* 128 bytes */
	111	# else
	112	# define DNAME_INLINE_LEN 40 /* 128 bytes */
	113	# endif
c2452f32	114	#endif
1da177e4 LT	115
1da177e4 LT	116	struct dentry {
44a7d7a8	117	/* RCU lookup touched fields */
1da177e4	118	unsigned int d_flags; /* protected by d_lock */
31e6b01f	119	seqcount_t d_seq; /* per dentry seqlock */
ceb5bdc2	120	struct hlist_bl_node d_hash; /* lookup hash list */
1da177e4 LT	121	struct dentry d_parent; / parent directory */
1da177e4 LT	122	struct qstr d_name;
44a7d7a8 NP	123	struct inode d_inode; / Where the name belongs to - NULL is
	124	* negative */
	125	unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
	126
	127	/* Ref lookup also touches following */
	128	unsigned int d_count; /* protected by d_lock */
	129	spinlock_t d_lock; /* per dentry lock */
	130	const struct dentry_operations *d_op;
	131	struct super_block d_sb; / The root of the dentry tree */
	132	unsigned long d_time; /* used by d_revalidate */
	133	void d_fsdata; / fs-specific data */
1da177e4 LT	134
1da177e4 LT	135	struct list_head d_lru; /* LRU list */
5160ee6f ED	136	/*
	137	* d_child and d_rcu can share memory
	138	*/
	139	union {
	140	struct list_head d_child; /* child of parent list */
	141	struct rcu_head d_rcu;
	142	} d_u;
1da177e4 LT	143	struct list_head d_subdirs; /* our children */
1da177e4 LT	144	struct list_head d_alias; /* inode alias list */
1da177e4 LT	145	};
1da177e4 LT	146
a90b9c05 IM	147	/*
	148	* dentry->d_lock spinlock nesting subclasses:
	149	*
	150	* 0: normal
	151	* 1: nested
	152	*/
	153	enum dentry_d_lock_class
	154	{
	155	DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
	156	DENTRY_D_LOCK_NESTED
	157	};
	158
1da177e4 LT	159	struct dentry_operations {
1da177e4 LT	160	int (d_revalidate)(struct dentry , struct nameidata *);
b1e6a015 NP	161	int (d_hash)(const struct dentry , const struct inode *,
b1e6a015 NP	162	struct qstr *);
621e155a NP	163	int (d_compare)(const struct dentry , const struct inode *,
	164	const struct dentry , const struct inode ,
	165	unsigned int, const char , const struct qstr );
fe15ce44	166	int (d_delete)(const struct dentry );
1da177e4 LT	167	void (d_release)(struct dentry );
1da177e4 LT	168	void (d_iput)(struct dentry , struct inode *);
c23fbb6b	169	char (d_dname)(struct dentry , char , int);
9875cf80	170	struct vfsmount (d_automount)(struct path *);
1aed3e42	171	int (d_manage)(struct dentry , bool);
44a7d7a8	172	} ____cacheline_aligned;
1da177e4	173
5eef7fa9 NP	174	/*
	175	* Locking rules for dentry_operations callbacks are to be found in
	176	* Documentation/filesystems/Locking. Keep it updated!
	177	*
621e155a NP	178	* FUrther descriptions are found in Documentation/filesystems/vfs.txt.
621e155a NP	179	* Keep it updated too!
1da177e4 LT	180	*/
	181
	182	/* d_flags entries */
830c0f0e LT	183	#define DCACHE_OP_HASH 0x0001
	184	#define DCACHE_OP_COMPARE 0x0002
	185	#define DCACHE_OP_REVALIDATE 0x0004
	186	#define DCACHE_OP_DELETE 0x0008
5f57cbcc	187
830c0f0e	188	#define DCACHE_DISCONNECTED 0x0010
5f57cbcc NP	189	/* This dentry is possibly not currently connected to the dcache tree, in
	190	* which case its parent will either be itself, or will have this flag as
	191	* well. nfsd will not use a dentry with this bit set, but will first
	192	* endeavour to clear the bit either by discovering that it is connected,
	193	* or by performing lookup operations. Any filesystem which supports
	194	* nfsd_operations MUST have a lookup function which, if it finds a
	195	* directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
	196	* dentry into place and return that dentry rather than the passed one,
	197	* typically using d_splice_alias. */
1da177e4	198
830c0f0e LT	199	#define DCACHE_REFERENCED 0x0020 /* Recently used, don't discard. */
830c0f0e LT	200	#define DCACHE_RCUACCESS 0x0040 /* Entry has ever been RCU-visible */
c28f7e56	201
d83c49f3	202	#define DCACHE_CANT_MOUNT 0x0100
949854d0	203	#define DCACHE_GENOCIDE 0x0200
5f57cbcc	204
830c0f0e LT	205	#define DCACHE_NFSFS_RENAMED 0x1000
	206	/* this dentry has been "silly renamed" and has to be deleted on the last
	207	* dput() */
	208	#define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */
	209	#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
	210	/* Parent inode is watched by some fsnotify listener */
fb045adb	211
9875cf80 DH	212	#define DCACHE_MOUNTED 0x10000 /* is a mountpoint */
9875cf80 DH	213	#define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */
cc53ce53	214	#define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */
44396f4b	215	#define DCACHE_NEED_LOOKUP 0x80000 /* dentry requires i_op->lookup */
9875cf80	216	#define DCACHE_MANAGED_DENTRY \
cc53ce53	217	(DCACHE_MOUNTED\|DCACHE_NEED_AUTOMOUNT\|DCACHE_MANAGE_TRANSIT)
9875cf80	218
74c3cbe3	219	extern seqlock_t rename_lock;
1da177e4	220
1da177e4 LT	221	static inline int dname_external(struct dentry *dentry)
	222	{
	223	return dentry->d_name.name != dentry->d_iname;
	224	}
	225
	226	/*
	227	* These are the low-level FS interfaces to the dcache..
	228	*/
	229	extern void d_instantiate(struct dentry , struct inode );
	230	extern struct dentry * d_instantiate_unique(struct dentry , struct inode );
770bfad8	231	extern struct dentry * d_materialise_unique(struct dentry , struct inode );
789680d1 NP	232	extern void __d_drop(struct dentry *dentry);
789680d1 NP	233	extern void d_drop(struct dentry *dentry);
1da177e4	234	extern void d_delete(struct dentry *);
fb045adb	235	extern void d_set_d_op(struct dentry dentry, const struct dentry_operations op);
1da177e4 LT	236
	237	/* allocate/de-allocate */
	238	extern struct dentry * d_alloc(struct dentry , const struct qstr );
4b936885	239	extern struct dentry * d_alloc_pseudo(struct super_block , const struct qstr );
1da177e4	240	extern struct dentry * d_splice_alias(struct inode , struct dentry );
e45b590b	241	extern struct dentry * d_add_ci(struct dentry , struct inode , struct qstr *);
4ea3ada2	242	extern struct dentry * d_obtain_alias(struct inode *);
1da177e4 LT	243	extern void shrink_dcache_sb(struct super_block *);
1da177e4 LT	244	extern void shrink_dcache_parent(struct dentry *);
c636ebdb	245	extern void shrink_dcache_for_umount(struct super_block *);
1da177e4 LT	246	extern int d_invalidate(struct dentry *);
	247
	248	/* only used at mount-time */
	249	extern struct dentry * d_alloc_root(struct inode *);
	250
	251	/* <clickety>-<click> the ramfs-type tree */
	252	extern void d_genocide(struct dentry *);
	253
	254	extern struct dentry d_find_alias(struct inode );
	255	extern void d_prune_aliases(struct inode *);
	256
	257	/* test whether we have any submounts in a subdir tree */
	258	extern int have_submounts(struct dentry *);
	259
	260	/*
	261	* This adds the entry to the hash queues.
	262	*/
	263	extern void d_rehash(struct dentry *);
	264
	265	/**
	266	* d_add - add dentry to hash queues
	267	* @entry: dentry to add
	268	* @inode: The inode to attach to this dentry
	269	*
	270	* This adds the entry to the hash queues and initializes @inode.
	271	* The entry was actually filled in earlier during d_alloc().
	272	*/
	273
	274	static inline void d_add(struct dentry entry, struct inode inode)
	275	{
	276	d_instantiate(entry, inode);
	277	d_rehash(entry);
	278	}
	279
	280	/**
	281	* d_add_unique - add dentry to hash queues without aliasing
	282	* @entry: dentry to add
	283	* @inode: The inode to attach to this dentry
	284	*
	285	* This adds the entry to the hash queues and initializes @inode.
	286	* The entry was actually filled in earlier during d_alloc().
	287	*/
	288	static inline struct dentry d_add_unique(struct dentry entry, struct inode *inode)
	289	{
	290	struct dentry *res;
	291
	292	res = d_instantiate_unique(entry, inode);
	293	d_rehash(res != NULL ? res : entry);
	294	return res;
	295	}
	296
fb2d5b86 NP	297	extern void dentry_update_name_case(struct dentry , struct qstr );
fb2d5b86 NP	298
1da177e4 LT	299	/* used for rename() and baskets */
1da177e4 LT	300	extern void d_move(struct dentry , struct dentry );
e2761a11	301	extern struct dentry d_ancestor(struct dentry , struct dentry *);
1da177e4 LT	302
1da177e4 LT	303	/* appendix may either be NULL or be used for transname suffixes */
31e6b01f NP	304	extern struct dentry d_lookup(struct dentry , struct qstr *);
	305	extern struct dentry d_hash_and_lookup(struct dentry , struct qstr *);
	306	extern struct dentry __d_lookup(struct dentry , struct qstr *);
	307	extern struct dentry __d_lookup_rcu(struct dentry parent, struct qstr *name,
	308	unsigned seq, struct inode *inode);
	309
	310	/**
	311	* __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok
	312	* @dentry: dentry to take a ref on
	313	* @seq: seqcount to verify against
2a8c0c68	314	* Returns: 0 on failure, else 1.
31e6b01f NP	315	*
	316	* __d_rcu_to_refcount operates on a dentry,seq pair that was returned
	317	* by __d_lookup_rcu, to get a reference on an rcu-walk dentry.
	318	*/
	319	static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq)
	320	{
	321	int ret = 0;
	322
	323	assert_spin_locked(&dentry->d_lock);
	324	if (!read_seqcount_retry(&dentry->d_seq, seq)) {
	325	ret = 1;
	326	dentry->d_count++;
	327	}
	328
	329	return ret;
	330	}
1da177e4 LT	331
	332	/* validate "insecure" dentry pointer */
	333	extern int d_validate(struct dentry , struct dentry );
	334
c23fbb6b ED	335	/*
	336	* helper function for dentry_operations.d_dname() members
	337	*/
	338	extern char dynamic_dname(struct dentry , char , int, const char , ...);
	339
9d1bc601	340	extern char __d_path(const struct path path, struct path root, char , int);
20d4fdc1	341	extern char d_path(const struct path , char *, int);
8df9d1a4	342	extern char d_path_with_unreachable(const struct path , char *, int);
ec2447c2	343	extern char dentry_path_raw(struct dentry , char *, int);
6092d048	344	extern char dentry_path(struct dentry , char *, int);
cf28b486	345
1da177e4 LT	346	/* Allocation counts.. */
	347
	348	/**
dc0474be	349	* dget, dget_dlock - get a reference to a dentry
1da177e4 LT	350	* @dentry: dentry to get a reference to
	351	*
	352	* Given a dentry or %NULL pointer increment the reference count
	353	* if appropriate and return the dentry. A dentry will not be
dc0474be	354	* destroyed when it has references.
1da177e4	355	*/
b7ab39f6 NP	356	static inline struct dentry dget_dlock(struct dentry dentry)
b7ab39f6 NP	357	{
dc0474be	358	if (dentry)
b7ab39f6	359	dentry->d_count++;
b7ab39f6 NP	360	return dentry;
b7ab39f6 NP	361	}
2fd6b7f5	362
1da177e4 LT	363	static inline struct dentry dget(struct dentry dentry)
	364	{
	365	if (dentry) {
b7ab39f6 NP	366	spin_lock(&dentry->d_lock);
	367	dget_dlock(dentry);
	368	spin_unlock(&dentry->d_lock);
1da177e4 LT	369	}
	370	return dentry;
	371	}
	372
b7ab39f6	373	extern struct dentry dget_parent(struct dentry dentry);
1da177e4 LT	374
	375	/**
	376	* d_unhashed - is dentry hashed
	377	* @dentry: entry to check
	378	*
	379	* Returns true if the dentry passed is not currently hashed.
	380	*/
	381
	382	static inline int d_unhashed(struct dentry *dentry)
	383	{
dea3667b	384	return hlist_bl_unhashed(&dentry->d_hash);
1da177e4 LT	385	}
1da177e4 LT	386
f3da392e AD	387	static inline int d_unlinked(struct dentry *dentry)
	388	{
	389	return d_unhashed(dentry) && !IS_ROOT(dentry);
	390	}
	391
d83c49f3 AV	392	static inline int cant_mount(struct dentry *dentry)
	393	{
	394	return (dentry->d_flags & DCACHE_CANT_MOUNT);
	395	}
	396
	397	static inline void dont_mount(struct dentry *dentry)
	398	{
	399	spin_lock(&dentry->d_lock);
	400	dentry->d_flags \|= DCACHE_CANT_MOUNT;
	401	spin_unlock(&dentry->d_lock);
	402	}
	403
1da177e4 LT	404	extern void dput(struct dentry *);
1da177e4 LT	405
cc53ce53 DH	406	static inline bool d_managed(struct dentry *dentry)
	407	{
	408	return dentry->d_flags & DCACHE_MANAGED_DENTRY;
	409	}
	410
	411	static inline bool d_mountpoint(struct dentry *dentry)
1da177e4	412	{
5f57cbcc	413	return dentry->d_flags & DCACHE_MOUNTED;
1da177e4 LT	414	}
1da177e4 LT	415
44396f4b JB	416	static inline bool d_need_lookup(struct dentry *dentry)
	417	{
	418	return dentry->d_flags & DCACHE_NEED_LOOKUP;
	419	}
	420
	421	extern void d_clear_need_lookup(struct dentry *dentry);
1da177e4 LT	422
	423	extern int sysctl_vfs_cache_pressure;
	424
1da177e4	425	#endif /* __LINUX_DCACHE_H */