[mirror_ubuntu-zesty-kernel.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)
{
	if (scount != tcount)
		return 1;

	do {
		if (*cs != *ct)
			return 1;
		cs++;
		ct++;
		tcount--;
	} while (tcount);
	return 0;
}

/* 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_alloc_root(struct inode *);
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
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	{
9d55c369 NP	57	if (scount != tcount)
9d55c369 NP	58	return 1;
5707c87f	59
9d55c369	60	do {
5707c87f LT	61	if (cs != ct)
5707c87f LT	62	return 1;
9d55c369 NP	63	cs++;
	64	ct++;
	65	tcount--;
	66	} while (tcount);
5707c87f	67	return 0;
9d55c369 NP	68	}
9d55c369 NP	69
1da177e4 LT	70	/* Name hashing routines. Initial hash value */
	71	/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
	72	#define init_name_hash() 0
	73
	74	/* partial hash update function. Assume roughly 4 bits per character */
	75	static inline unsigned long
	76	partial_name_hash(unsigned long c, unsigned long prevhash)
	77	{
	78	return (prevhash + (c << 4) + (c >> 4)) * 11;
	79	}
	80
	81	/*
	82	* Finally: cut down the number of bits to a int value (and try to avoid
	83	* losing bits)
	84	*/
	85	static inline unsigned long end_name_hash(unsigned long hash)
	86	{
	87	return (unsigned int) hash;
	88	}
	89
	90	/* Compute the hash for a name string. */
0145acc2	91	extern unsigned int full_name_hash(const unsigned char *, unsigned int);
1da177e4	92
c2452f32 NP	93	/*
	94	* Try to keep struct dentry aligned on 64 byte cachelines (this will
	95	* give reasonable cacheline footprint with larger lines without the
	96	* large memory footprint increase).
	97	*/
	98	#ifdef CONFIG_64BIT
44a7d7a8	99	# define DNAME_INLINE_LEN 32 /* 192 bytes */
c2452f32	100	#else
44a7d7a8 NP	101	# ifdef CONFIG_SMP
	102	# define DNAME_INLINE_LEN 36 /* 128 bytes */
	103	# else
	104	# define DNAME_INLINE_LEN 40 /* 128 bytes */
	105	# endif
c2452f32	106	#endif
1da177e4 LT	107
1da177e4 LT	108	struct dentry {
44a7d7a8	109	/* RCU lookup touched fields */
1da177e4	110	unsigned int d_flags; /* protected by d_lock */
31e6b01f	111	seqcount_t d_seq; /* per dentry seqlock */
ceb5bdc2	112	struct hlist_bl_node d_hash; /* lookup hash list */
1da177e4 LT	113	struct dentry d_parent; / parent directory */
1da177e4 LT	114	struct qstr d_name;
44a7d7a8 NP	115	struct inode d_inode; / Where the name belongs to - NULL is
	116	* negative */
	117	unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
	118
	119	/* Ref lookup also touches following */
	120	unsigned int d_count; /* protected by d_lock */
	121	spinlock_t d_lock; /* per dentry lock */
	122	const struct dentry_operations *d_op;
	123	struct super_block d_sb; / The root of the dentry tree */
	124	unsigned long d_time; /* used by d_revalidate */
	125	void d_fsdata; / fs-specific data */
1da177e4 LT	126
1da177e4 LT	127	struct list_head d_lru; /* LRU list */
5160ee6f ED	128	/*
	129	* d_child and d_rcu can share memory
	130	*/
	131	union {
	132	struct list_head d_child; /* child of parent list */
	133	struct rcu_head d_rcu;
	134	} d_u;
1da177e4 LT	135	struct list_head d_subdirs; /* our children */
1da177e4 LT	136	struct list_head d_alias; /* inode alias list */
1da177e4 LT	137	};
1da177e4 LT	138
a90b9c05 IM	139	/*
	140	* dentry->d_lock spinlock nesting subclasses:
	141	*
	142	* 0: normal
	143	* 1: nested
	144	*/
	145	enum dentry_d_lock_class
	146	{
	147	DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
	148	DENTRY_D_LOCK_NESTED
	149	};
	150
1da177e4 LT	151	struct dentry_operations {
1da177e4 LT	152	int (d_revalidate)(struct dentry , struct nameidata *);
b1e6a015 NP	153	int (d_hash)(const struct dentry , const struct inode *,
b1e6a015 NP	154	struct qstr *);
621e155a NP	155	int (d_compare)(const struct dentry , const struct inode *,
	156	const struct dentry , const struct inode ,
	157	unsigned int, const char , const struct qstr );
fe15ce44	158	int (d_delete)(const struct dentry );
1da177e4	159	void (d_release)(struct dentry );
f0023bc6	160	void (d_prune)(struct dentry );
1da177e4	161	void (d_iput)(struct dentry , struct inode *);
c23fbb6b	162	char (d_dname)(struct dentry , char , int);
9875cf80	163	struct vfsmount (d_automount)(struct path *);
1aed3e42	164	int (d_manage)(struct dentry , bool);
44a7d7a8	165	} ____cacheline_aligned;
1da177e4	166
5eef7fa9 NP	167	/*
	168	* Locking rules for dentry_operations callbacks are to be found in
	169	* Documentation/filesystems/Locking. Keep it updated!
	170	*
621e155a NP	171	* FUrther descriptions are found in Documentation/filesystems/vfs.txt.
621e155a NP	172	* Keep it updated too!
1da177e4 LT	173	*/
	174
	175	/* d_flags entries */
830c0f0e LT	176	#define DCACHE_OP_HASH 0x0001
	177	#define DCACHE_OP_COMPARE 0x0002
	178	#define DCACHE_OP_REVALIDATE 0x0004
	179	#define DCACHE_OP_DELETE 0x0008
f0023bc6	180	#define DCACHE_OP_PRUNE 0x0010
5f57cbcc	181
f0023bc6	182	#define DCACHE_DISCONNECTED 0x0020
5f57cbcc NP	183	/* This dentry is possibly not currently connected to the dcache tree, in
	184	* which case its parent will either be itself, or will have this flag as
	185	* well. nfsd will not use a dentry with this bit set, but will first
	186	* endeavour to clear the bit either by discovering that it is connected,
	187	* or by performing lookup operations. Any filesystem which supports
	188	* nfsd_operations MUST have a lookup function which, if it finds a
	189	* directory inode with a DCACHE_DISCONNECTED dentry, will d_move that
	190	* dentry into place and return that dentry rather than the passed one,
	191	* typically using d_splice_alias. */
1da177e4	192
f0023bc6 SW	193	#define DCACHE_REFERENCED 0x0040 /* Recently used, don't discard. */
f0023bc6 SW	194	#define DCACHE_RCUACCESS 0x0080 /* Entry has ever been RCU-visible */
c28f7e56	195
d83c49f3	196	#define DCACHE_CANT_MOUNT 0x0100
949854d0	197	#define DCACHE_GENOCIDE 0x0200
eaf5f907	198	#define DCACHE_SHRINK_LIST 0x0400
5f57cbcc	199
830c0f0e LT	200	#define DCACHE_NFSFS_RENAMED 0x1000
	201	/* this dentry has been "silly renamed" and has to be deleted on the last
	202	* dput() */
	203	#define DCACHE_COOKIE 0x2000 /* For use by dcookie subsystem */
	204	#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x4000
	205	/* Parent inode is watched by some fsnotify listener */
fb045adb	206
9875cf80 DH	207	#define DCACHE_MOUNTED 0x10000 /* is a mountpoint */
9875cf80 DH	208	#define DCACHE_NEED_AUTOMOUNT 0x20000 /* handle automount on this dir */
cc53ce53	209	#define DCACHE_MANAGE_TRANSIT 0x40000 /* manage transit from this dirent */
44396f4b	210	#define DCACHE_NEED_LOOKUP 0x80000 /* dentry requires i_op->lookup */
9875cf80	211	#define DCACHE_MANAGED_DENTRY \
cc53ce53	212	(DCACHE_MOUNTED\|DCACHE_NEED_AUTOMOUNT\|DCACHE_MANAGE_TRANSIT)
9875cf80	213
74c3cbe3	214	extern seqlock_t rename_lock;
1da177e4	215
1da177e4 LT	216	static inline int dname_external(struct dentry *dentry)
	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 */
	245	extern struct dentry * d_alloc_root(struct inode *);
adc0e91a	246	extern struct dentry * d_make_root(struct inode *);
1da177e4 LT	247
	248	/* <clickety>-<click> the ramfs-type tree */
	249	extern void d_genocide(struct dentry *);
	250
	251	extern struct dentry d_find_alias(struct inode );
	252	extern void d_prune_aliases(struct inode *);
	253
	254	/* test whether we have any submounts in a subdir tree */
	255	extern int have_submounts(struct dentry *);
	256
	257	/*
	258	* This adds the entry to the hash queues.
	259	*/
	260	extern void d_rehash(struct dentry *);
	261
	262	/**
	263	* d_add - add dentry to hash queues
	264	* @entry: dentry to add
	265	* @inode: The inode to attach to this dentry
	266	*
	267	* This adds the entry to the hash queues and initializes @inode.
	268	* The entry was actually filled in earlier during d_alloc().
	269	*/
	270
	271	static inline void d_add(struct dentry entry, struct inode inode)
	272	{
	273	d_instantiate(entry, inode);
	274	d_rehash(entry);
	275	}
	276
	277	/**
	278	* d_add_unique - add dentry to hash queues without aliasing
	279	* @entry: dentry to add
	280	* @inode: The inode to attach to this dentry
	281	*
	282	* This adds the entry to the hash queues and initializes @inode.
	283	* The entry was actually filled in earlier during d_alloc().
	284	*/
	285	static inline struct dentry d_add_unique(struct dentry entry, struct inode *inode)
	286	{
	287	struct dentry *res;
	288
	289	res = d_instantiate_unique(entry, inode);
	290	d_rehash(res != NULL ? res : entry);
	291	return res;
	292	}
	293
fb2d5b86 NP	294	extern void dentry_update_name_case(struct dentry , struct qstr );
fb2d5b86 NP	295
1da177e4 LT	296	/* used for rename() and baskets */
1da177e4 LT	297	extern void d_move(struct dentry , struct dentry );
e2761a11	298	extern struct dentry d_ancestor(struct dentry , struct dentry *);
1da177e4 LT	299
1da177e4 LT	300	/* appendix may either be NULL or be used for transname suffixes */
31e6b01f NP	301	extern struct dentry d_lookup(struct dentry , struct qstr *);
	302	extern struct dentry d_hash_and_lookup(struct dentry , struct qstr *);
	303	extern struct dentry __d_lookup(struct dentry , struct qstr *);
8966be90 LT	304	extern struct dentry __d_lookup_rcu(const struct dentry parent,
8966be90 LT	305	const struct qstr *name,
31e6b01f NP	306	unsigned seq, struct inode *inode);
	307
	308	/**
	309	* __d_rcu_to_refcount - take a refcount on dentry if sequence check is ok
	310	* @dentry: dentry to take a ref on
	311	* @seq: seqcount to verify against
2a8c0c68	312	* Returns: 0 on failure, else 1.
31e6b01f NP	313	*
	314	* __d_rcu_to_refcount operates on a dentry,seq pair that was returned
	315	* by __d_lookup_rcu, to get a reference on an rcu-walk dentry.
	316	*/
	317	static inline int __d_rcu_to_refcount(struct dentry *dentry, unsigned seq)
	318	{
	319	int ret = 0;
	320
	321	assert_spin_locked(&dentry->d_lock);
	322	if (!read_seqcount_retry(&dentry->d_seq, seq)) {
	323	ret = 1;
	324	dentry->d_count++;
	325	}
	326
	327	return ret;
	328	}
1da177e4 LT	329
	330	/* validate "insecure" dentry pointer */
	331	extern int d_validate(struct dentry , struct dentry );
	332
c23fbb6b ED	333	/*
	334	* helper function for dentry_operations.d_dname() members
	335	*/
	336	extern char dynamic_dname(struct dentry , char , int, const char , ...);
	337
02125a82 AV	338	extern char __d_path(const struct path , const struct path , char , int);
02125a82 AV	339	extern char d_absolute_path(const struct path , char *, int);
20d4fdc1	340	extern char d_path(const struct path , char *, int);
8df9d1a4	341	extern char d_path_with_unreachable(const struct path , char *, int);
ec2447c2	342	extern char dentry_path_raw(struct dentry , char *, int);
6092d048	343	extern char dentry_path(struct dentry , char *, int);
cf28b486	344
1da177e4 LT	345	/* Allocation counts.. */
	346
	347	/**
dc0474be	348	* dget, dget_dlock - get a reference to a dentry
1da177e4 LT	349	* @dentry: dentry to get a reference to
	350	*
	351	* Given a dentry or %NULL pointer increment the reference count
	352	* if appropriate and return the dentry. A dentry will not be
dc0474be	353	* destroyed when it has references.
1da177e4	354	*/
b7ab39f6 NP	355	static inline struct dentry dget_dlock(struct dentry dentry)
b7ab39f6 NP	356	{
dc0474be	357	if (dentry)
b7ab39f6	358	dentry->d_count++;
b7ab39f6 NP	359	return dentry;
b7ab39f6 NP	360	}
2fd6b7f5	361
1da177e4 LT	362	static inline struct dentry dget(struct dentry dentry)
	363	{
	364	if (dentry) {
b7ab39f6 NP	365	spin_lock(&dentry->d_lock);
	366	dget_dlock(dentry);
	367	spin_unlock(&dentry->d_lock);
1da177e4 LT	368	}
	369	return dentry;
	370	}
	371
b7ab39f6	372	extern struct dentry dget_parent(struct dentry dentry);
1da177e4 LT	373
	374	/**
	375	* d_unhashed - is dentry hashed
	376	* @dentry: entry to check
	377	*
	378	* Returns true if the dentry passed is not currently hashed.
	379	*/
	380
	381	static inline int d_unhashed(struct dentry *dentry)
	382	{
dea3667b	383	return hlist_bl_unhashed(&dentry->d_hash);
1da177e4 LT	384	}
1da177e4 LT	385
f3da392e AD	386	static inline int d_unlinked(struct dentry *dentry)
	387	{
	388	return d_unhashed(dentry) && !IS_ROOT(dentry);
	389	}
	390
d83c49f3 AV	391	static inline int cant_mount(struct dentry *dentry)
	392	{
	393	return (dentry->d_flags & DCACHE_CANT_MOUNT);
	394	}
	395
	396	static inline void dont_mount(struct dentry *dentry)
	397	{
	398	spin_lock(&dentry->d_lock);
	399	dentry->d_flags \|= DCACHE_CANT_MOUNT;
	400	spin_unlock(&dentry->d_lock);
	401	}
	402
1da177e4 LT	403	extern void dput(struct dentry *);
1da177e4 LT	404
cc53ce53 DH	405	static inline bool d_managed(struct dentry *dentry)
	406	{
	407	return dentry->d_flags & DCACHE_MANAGED_DENTRY;
	408	}
	409
	410	static inline bool d_mountpoint(struct dentry *dentry)
1da177e4	411	{
5f57cbcc	412	return dentry->d_flags & DCACHE_MOUNTED;
1da177e4 LT	413	}
1da177e4 LT	414
44396f4b JB	415	static inline bool d_need_lookup(struct dentry *dentry)
	416	{
	417	return dentry->d_flags & DCACHE_NEED_LOOKUP;
	418	}
	419
	420	extern void d_clear_need_lookup(struct dentry *dentry);
1da177e4 LT	421
	422	extern int sysctl_vfs_cache_pressure;
	423
1da177e4	424	#endif /* __LINUX_DCACHE_H */