[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;

/* 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

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_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_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_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 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(const struct dentry *parent,
				const 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 *, 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 *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
	50	/* Name hashing routines. Initial hash value */
	51	/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
	52	#define init_name_hash() 0
	53
	54	/* partial hash update function. Assume roughly 4 bits per character */
	55	static inline unsigned long
	56	partial_name_hash(unsigned long c, unsigned long prevhash)
	57	{
	58	return (prevhash + (c << 4) + (c >> 4)) * 11;
	59	}
	60
	61	/*
	62	* Finally: cut down the number of bits to a int value (and try to avoid
	63	* losing bits)
	64	*/
	65	static inline unsigned long end_name_hash(unsigned long hash)
	66	{
	67	return (unsigned int) hash;
	68	}
	69
	70	/* Compute the hash for a name string. */
0145acc2	71	extern unsigned int full_name_hash(const unsigned char *, unsigned int);
1da177e4	72
c2452f32 NP	73	/*
	74	* Try to keep struct dentry aligned on 64 byte cachelines (this will
	75	* give reasonable cacheline footprint with larger lines without the
	76	* large memory footprint increase).
	77	*/
	78	#ifdef CONFIG_64BIT
44a7d7a8	79	# define DNAME_INLINE_LEN 32 /* 192 bytes */
c2452f32	80	#else
44a7d7a8 NP	81	# ifdef CONFIG_SMP
	82	# define DNAME_INLINE_LEN 36 /* 128 bytes */
	83	# else
	84	# define DNAME_INLINE_LEN 40 /* 128 bytes */
	85	# endif
c2452f32	86	#endif
1da177e4 LT	87
1da177e4 LT	88	struct dentry {
44a7d7a8	89	/* RCU lookup touched fields */
1da177e4	90	unsigned int d_flags; /* protected by d_lock */
31e6b01f	91	seqcount_t d_seq; /* per dentry seqlock */
ceb5bdc2	92	struct hlist_bl_node d_hash; /* lookup hash list */
1da177e4 LT	93	struct dentry d_parent; / parent directory */
1da177e4 LT	94	struct qstr d_name;
44a7d7a8 NP	95	struct inode d_inode; / Where the name belongs to - NULL is
	96	* negative */
	97	unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
	98
	99	/* Ref lookup also touches following */
	100	unsigned int d_count; /* protected by d_lock */
	101	spinlock_t d_lock; /* per dentry lock */
	102	const struct dentry_operations *d_op;
	103	struct super_block d_sb; / The root of the dentry tree */
	104	unsigned long d_time; /* used by d_revalidate */
	105	void d_fsdata; / fs-specific data */
1da177e4 LT	106
1da177e4 LT	107	struct list_head d_lru; /* LRU list */
5160ee6f ED	108	/*
	109	* d_child and d_rcu can share memory
	110	*/
	111	union {
	112	struct list_head d_child; /* child of parent list */
	113	struct rcu_head d_rcu;
	114	} d_u;
1da177e4 LT	115	struct list_head d_subdirs; /* our children */
1da177e4 LT	116	struct list_head d_alias; /* inode alias list */
1da177e4 LT	117	};
1da177e4 LT	118
a90b9c05 IM	119	/*
	120	* dentry->d_lock spinlock nesting subclasses:
	121	*
	122	* 0: normal
	123	* 1: nested
	124	*/
	125	enum dentry_d_lock_class
	126	{
	127	DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
	128	DENTRY_D_LOCK_NESTED
	129	};
	130
1da177e4 LT	131	struct dentry_operations {
1da177e4 LT	132	int (d_revalidate)(struct dentry , struct nameidata *);
b1e6a015 NP	133	int (d_hash)(const struct dentry , const struct inode *,
b1e6a015 NP	134	struct qstr *);
621e155a NP	135	int (d_compare)(const struct dentry , const struct inode *,
	136	const struct dentry , const struct inode ,
	137	unsigned int, const char , const struct qstr );
fe15ce44	138	int (d_delete)(const struct dentry );
1da177e4	139	void (d_release)(struct dentry );
f0023bc6	140	void (d_prune)(struct dentry );
1da177e4	141	void (d_iput)(struct dentry , struct inode *);
c23fbb6b	142	char (d_dname)(struct dentry , char , int);
9875cf80	143	struct vfsmount (d_automount)(struct path *);
1aed3e42	144	int (d_manage)(struct dentry , bool);
44a7d7a8	145	} ____cacheline_aligned;
1da177e4	146
5eef7fa9 NP	147	/*
	148	* Locking rules for dentry_operations callbacks are to be found in
	149	* Documentation/filesystems/Locking. Keep it updated!
	150	*
621e155a NP	151	* FUrther descriptions are found in Documentation/filesystems/vfs.txt.
621e155a NP	152	* Keep it updated too!
1da177e4 LT	153	*/
	154
	155	/* d_flags entries */
830c0f0e LT	156	#define DCACHE_OP_HASH 0x0001
	157	#define DCACHE_OP_COMPARE 0x0002
	158	#define DCACHE_OP_REVALIDATE 0x0004
	159	#define DCACHE_OP_DELETE 0x0008
f0023bc6	160	#define DCACHE_OP_PRUNE 0x0010
5f57cbcc	161
f0023bc6	162	#define DCACHE_DISCONNECTED 0x0020
5f57cbcc NP	163	/* This dentry is possibly not currently connected to the dcache tree, in
	164	* which case its parent will either be itself, or will have this flag as
	165	* well. nfsd will not use a dentry with this bit set, but will first
	166	* endeavour to clear the bit either by discovering that it is connected,
	167	* or by performing lookup operations. Any filesystem which supports
	168	* nfsd_operations MUST have a lookup function which, if it finds a
	169	* directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
	170	* dentry into place and return that dentry rather than the passed one,
	171	* typically using d_splice_alias. */
1da177e4	172
f0023bc6 SW	173	#define DCACHE_REFERENCED 0x0040 /* Recently used, don't discard. */
f0023bc6 SW	174	#define DCACHE_RCUACCESS 0x0080 /* Entry has ever been RCU-visible */
c28f7e56	175
d83c49f3	176	#define DCACHE_CANT_MOUNT 0x0100
949854d0	177	#define DCACHE_GENOCIDE 0x0200
eaf5f907	178	#define DCACHE_SHRINK_LIST 0x0400
5f57cbcc	179
830c0f0e LT	180	#define DCACHE_NFSFS_RENAMED 0x1000
	181	/* this dentry has been "silly renamed" and has to be deleted on the last
	182	* dput() */
	183	#define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */
	184	#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
	185	/* Parent inode is watched by some fsnotify listener */
fb045adb	186
9875cf80 DH	187	#define DCACHE_MOUNTED 0x10000 /* is a mountpoint */
9875cf80 DH	188	#define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */
cc53ce53	189	#define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */
44396f4b	190	#define DCACHE_NEED_LOOKUP 0x80000 /* dentry requires i_op->lookup */
9875cf80	191	#define DCACHE_MANAGED_DENTRY \
cc53ce53	192	(DCACHE_MOUNTED\|DCACHE_NEED_AUTOMOUNT\|DCACHE_MANAGE_TRANSIT)
9875cf80	193
74c3cbe3	194	extern seqlock_t rename_lock;
1da177e4	195
1da177e4 LT	196	static inline int dname_external(struct dentry *dentry)
	197	{
	198	return dentry->d_name.name != dentry->d_iname;
	199	}
	200
	201	/*
	202	* These are the low-level FS interfaces to the dcache..
	203	*/
	204	extern void d_instantiate(struct dentry , struct inode );
	205	extern struct dentry * d_instantiate_unique(struct dentry , struct inode );
770bfad8	206	extern struct dentry * d_materialise_unique(struct dentry , struct inode );
789680d1 NP	207	extern void __d_drop(struct dentry *dentry);
789680d1 NP	208	extern void d_drop(struct dentry *dentry);
1da177e4	209	extern void d_delete(struct dentry *);
fb045adb	210	extern void d_set_d_op(struct dentry dentry, const struct dentry_operations op);
1da177e4 LT	211
	212	/* allocate/de-allocate */
	213	extern struct dentry * d_alloc(struct dentry , const struct qstr );
4b936885	214	extern struct dentry * d_alloc_pseudo(struct super_block , const struct qstr );
1da177e4	215	extern struct dentry * d_splice_alias(struct inode , struct dentry );
e45b590b	216	extern struct dentry * d_add_ci(struct dentry , struct inode , struct qstr *);
46f72b34	217	extern struct dentry d_find_any_alias(struct inode inode);
4ea3ada2	218	extern struct dentry * d_obtain_alias(struct inode *);
1da177e4 LT	219	extern void shrink_dcache_sb(struct super_block *);
1da177e4 LT	220	extern void shrink_dcache_parent(struct dentry *);
c636ebdb	221	extern void shrink_dcache_for_umount(struct super_block *);
1da177e4 LT	222	extern int d_invalidate(struct dentry *);
	223
	224	/* only used at mount-time */
adc0e91a	225	extern struct dentry * d_make_root(struct inode *);
1da177e4 LT	226
	227	/* <clickety>-<click> the ramfs-type tree */
	228	extern void d_genocide(struct dentry *);
	229
	230	extern struct dentry d_find_alias(struct inode );
	231	extern void d_prune_aliases(struct inode *);
	232
	233	/* test whether we have any submounts in a subdir tree */
	234	extern int have_submounts(struct dentry *);
	235
	236	/*
	237	* This adds the entry to the hash queues.
	238	*/
	239	extern void d_rehash(struct dentry *);
	240
	241	/**
	242	* d_add - add dentry to hash queues
	243	* @entry: dentry to add
	244	* @inode: The inode to attach to this dentry
	245	*
	246	* This adds the entry to the hash queues and initializes @inode.
	247	* The entry was actually filled in earlier during d_alloc().
	248	*/
	249
	250	static inline void d_add(struct dentry entry, struct inode inode)
	251	{
	252	d_instantiate(entry, inode);
	253	d_rehash(entry);
	254	}
	255
	256	/**
	257	* d_add_unique - add dentry to hash queues without aliasing
	258	* @entry: dentry to add
	259	* @inode: The inode to attach to this dentry
	260	*
	261	* This adds the entry to the hash queues and initializes @inode.
	262	* The entry was actually filled in earlier during d_alloc().
	263	*/
	264	static inline struct dentry d_add_unique(struct dentry entry, struct inode *inode)
	265	{
	266	struct dentry *res;
	267
	268	res = d_instantiate_unique(entry, inode);
	269	d_rehash(res != NULL ? res : entry);
	270	return res;
	271	}
	272
fb2d5b86 NP	273	extern void dentry_update_name_case(struct dentry , struct qstr );
fb2d5b86 NP	274
1da177e4 LT	275	/* used for rename() and baskets */
1da177e4 LT	276	extern void d_move(struct dentry , struct dentry );
e2761a11	277	extern struct dentry d_ancestor(struct dentry , struct dentry *);
1da177e4 LT	278
1da177e4 LT	279	/* appendix may either be NULL or be used for transname suffixes */
31e6b01f NP	280	extern struct dentry d_lookup(struct dentry , struct qstr *);
	281	extern struct dentry d_hash_and_lookup(struct dentry , struct qstr *);
	282	extern struct dentry __d_lookup(struct dentry , struct qstr *);
8966be90 LT	283	extern struct dentry __d_lookup_rcu(const struct dentry parent,
8966be90 LT	284	const struct qstr *name,
12f8ad4b	285	unsigned seq, struct inode inode);
31e6b01f NP	286
	287	/**
	288	* __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok
	289	* @dentry: dentry to take a ref on
	290	* @seq: seqcount to verify against
2a8c0c68	291	* Returns: 0 on failure, else 1.
31e6b01f NP	292	*
	293	* __d_rcu_to_refcount operates on a dentry,seq pair that was returned
	294	* by __d_lookup_rcu, to get a reference on an rcu-walk dentry.
	295	*/
	296	static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq)
	297	{
	298	int ret = 0;
	299
	300	assert_spin_locked(&dentry->d_lock);
	301	if (!read_seqcount_retry(&dentry->d_seq, seq)) {
	302	ret = 1;
	303	dentry->d_count++;
	304	}
	305
	306	return ret;
	307	}
1da177e4 LT	308
	309	/* validate "insecure" dentry pointer */
	310	extern int d_validate(struct dentry , struct dentry );
	311
c23fbb6b ED	312	/*
	313	* helper function for dentry_operations.d_dname() members
	314	*/
	315	extern char dynamic_dname(struct dentry , char , int, const char , ...);
	316
02125a82 AV	317	extern char __d_path(const struct path , const struct path , char , int);
02125a82 AV	318	extern char d_absolute_path(const struct path , char *, int);
20d4fdc1	319	extern char d_path(const struct path , char *, int);
8df9d1a4	320	extern char d_path_with_unreachable(const struct path , char *, int);
ec2447c2	321	extern char dentry_path_raw(struct dentry , char *, int);
6092d048	322	extern char dentry_path(struct dentry , char *, int);
cf28b486	323
1da177e4 LT	324	/* Allocation counts.. */
	325
	326	/**
dc0474be	327	* dget, dget_dlock - get a reference to a dentry
1da177e4 LT	328	* @dentry: dentry to get a reference to
	329	*
	330	* Given a dentry or %NULL pointer increment the reference count
	331	* if appropriate and return the dentry. A dentry will not be
dc0474be	332	* destroyed when it has references.
1da177e4	333	*/
b7ab39f6 NP	334	static inline struct dentry dget_dlock(struct dentry dentry)
b7ab39f6 NP	335	{
dc0474be	336	if (dentry)
b7ab39f6	337	dentry->d_count++;
b7ab39f6 NP	338	return dentry;
b7ab39f6 NP	339	}
2fd6b7f5	340
1da177e4 LT	341	static inline struct dentry dget(struct dentry dentry)
	342	{
	343	if (dentry) {
b7ab39f6 NP	344	spin_lock(&dentry->d_lock);
	345	dget_dlock(dentry);
	346	spin_unlock(&dentry->d_lock);
1da177e4 LT	347	}
	348	return dentry;
	349	}
	350
b7ab39f6	351	extern struct dentry dget_parent(struct dentry dentry);
1da177e4 LT	352
	353	/**
	354	* d_unhashed - is dentry hashed
	355	* @dentry: entry to check
	356	*
	357	* Returns true if the dentry passed is not currently hashed.
	358	*/
	359
	360	static inline int d_unhashed(struct dentry *dentry)
	361	{
dea3667b	362	return hlist_bl_unhashed(&dentry->d_hash);
1da177e4 LT	363	}
1da177e4 LT	364
f3da392e AD	365	static inline int d_unlinked(struct dentry *dentry)
	366	{
	367	return d_unhashed(dentry) && !IS_ROOT(dentry);
	368	}
	369
d83c49f3 AV	370	static inline int cant_mount(struct dentry *dentry)
	371	{
	372	return (dentry->d_flags & DCACHE_CANT_MOUNT);
	373	}
	374
	375	static inline void dont_mount(struct dentry *dentry)
	376	{
	377	spin_lock(&dentry->d_lock);
	378	dentry->d_flags \|= DCACHE_CANT_MOUNT;
	379	spin_unlock(&dentry->d_lock);
	380	}
	381
1da177e4 LT	382	extern void dput(struct dentry *);
1da177e4 LT	383
cc53ce53 DH	384	static inline bool d_managed(struct dentry *dentry)
	385	{
	386	return dentry->d_flags & DCACHE_MANAGED_DENTRY;
	387	}
	388
	389	static inline bool d_mountpoint(struct dentry *dentry)
1da177e4	390	{
5f57cbcc	391	return dentry->d_flags & DCACHE_MOUNTED;
1da177e4 LT	392	}
1da177e4 LT	393
44396f4b JB	394	static inline bool d_need_lookup(struct dentry *dentry)
	395	{
	396	return dentry->d_flags & DCACHE_NEED_LOOKUP;
	397	}
	398
	399	extern void d_clear_need_lookup(struct dentry *dentry);
1da177e4 LT	400
	401	extern int sysctl_vfs_cache_pressure;
	402
1da177e4	403	#endif /* __LINUX_DCACHE_H */