471 lines
14 KiB
C
471 lines
14 KiB
C
#ifndef __LINUX_DCACHE_H
|
|
#define __LINUX_DCACHE_H
|
|
|
|
#include <linux/atomic.h>
|
|
#include <linux/list.h>
|
|
#include <linux/rculist.h>
|
|
#include <linux/rculist_bl.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/seqlock.h>
|
|
#include <linux/cache.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/lockref.h>
|
|
|
|
struct path;
|
|
struct vfsmount;
|
|
|
|
/*
|
|
* linux/include/linux/dcache.h
|
|
*
|
|
* Dirent cache data structures
|
|
*
|
|
* (C) Copyright 1997 Thomas Schoebel-Theuer,
|
|
* with heavy changes by Linus Torvalds
|
|
*/
|
|
|
|
#define IS_ROOT(x) ((x) == (x)->d_parent)
|
|
|
|
/* The hash is always the low bits of hash_len */
|
|
#ifdef __LITTLE_ENDIAN
|
|
#define HASH_LEN_DECLARE u32 hash; u32 len;
|
|
#define bytemask_from_count(cnt) (~(~0ul << (cnt)*8))
|
|
#else
|
|
#define HASH_LEN_DECLARE u32 len; u32 hash;
|
|
#define bytemask_from_count(cnt) (~(~0ul >> (cnt)*8))
|
|
#endif
|
|
|
|
/*
|
|
* "quick string" -- eases parameter passing, but more importantly
|
|
* saves "metadata" about the string (ie length and the hash).
|
|
*
|
|
* hash comes first so it snuggles against d_parent in the
|
|
* dentry.
|
|
*/
|
|
struct qstr {
|
|
union {
|
|
struct {
|
|
HASH_LEN_DECLARE;
|
|
};
|
|
u64 hash_len;
|
|
};
|
|
const unsigned char *name;
|
|
};
|
|
|
|
#define QSTR_INIT(n,l) { { { .len = l } }, .name = n }
|
|
#define hashlen_hash(hashlen) ((u32) (hashlen))
|
|
#define hashlen_len(hashlen) ((u32)((hashlen) >> 32))
|
|
#define hashlen_create(hash,len) (((u64)(len)<<32)|(u32)(hash))
|
|
|
|
struct dentry_stat_t {
|
|
long nr_dentry;
|
|
long nr_unused;
|
|
long age_limit; /* age in seconds */
|
|
long want_pages; /* pages requested by system */
|
|
long dummy[2];
|
|
};
|
|
extern struct dentry_stat_t dentry_stat;
|
|
|
|
/* Name hashing routines. Initial hash value */
|
|
/* Hash courtesy of the R5 hash in reiserfs modulo sign bits */
|
|
#define init_name_hash() 0
|
|
|
|
/* partial hash update function. Assume roughly 4 bits per character */
|
|
static inline unsigned long
|
|
partial_name_hash(unsigned long c, unsigned long prevhash)
|
|
{
|
|
return (prevhash + (c << 4) + (c >> 4)) * 11;
|
|
}
|
|
|
|
/*
|
|
* Finally: cut down the number of bits to a int value (and try to avoid
|
|
* losing bits)
|
|
*/
|
|
static inline unsigned long end_name_hash(unsigned long hash)
|
|
{
|
|
return (unsigned int) hash;
|
|
}
|
|
|
|
/* Compute the hash for a name string. */
|
|
extern unsigned int full_name_hash(const unsigned char *, unsigned int);
|
|
|
|
/*
|
|
* Try to keep struct dentry aligned on 64 byte cachelines (this will
|
|
* give reasonable cacheline footprint with larger lines without the
|
|
* large memory footprint increase).
|
|
*/
|
|
#ifdef CONFIG_64BIT
|
|
# define DNAME_INLINE_LEN 32 /* 192 bytes */
|
|
#else
|
|
# ifdef CONFIG_SMP
|
|
# define DNAME_INLINE_LEN 36 /* 128 bytes */
|
|
# else
|
|
# define DNAME_INLINE_LEN 40 /* 128 bytes */
|
|
# endif
|
|
#endif
|
|
|
|
#define d_lock d_lockref.lock
|
|
|
|
struct dentry {
|
|
/* RCU lookup touched fields */
|
|
unsigned int d_flags; /* protected by d_lock */
|
|
seqcount_t d_seq; /* per dentry seqlock */
|
|
struct hlist_bl_node d_hash; /* lookup hash list */
|
|
struct dentry *d_parent; /* parent directory */
|
|
struct qstr d_name;
|
|
struct inode *d_inode; /* Where the name belongs to - NULL is
|
|
* negative */
|
|
unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
|
|
|
|
/* Ref lookup also touches following */
|
|
struct lockref d_lockref; /* per-dentry lock and refcount */
|
|
const struct dentry_operations *d_op;
|
|
struct super_block *d_sb; /* The root of the dentry tree */
|
|
unsigned long d_time; /* used by d_revalidate */
|
|
void *d_fsdata; /* fs-specific data */
|
|
|
|
struct list_head d_lru; /* LRU list */
|
|
/*
|
|
* d_child and d_rcu can share memory
|
|
*/
|
|
union {
|
|
struct list_head d_child; /* child of parent list */
|
|
struct rcu_head d_rcu;
|
|
} d_u;
|
|
struct list_head d_subdirs; /* our children */
|
|
struct hlist_node d_alias; /* inode alias list */
|
|
};
|
|
|
|
/*
|
|
* dentry->d_lock spinlock nesting subclasses:
|
|
*
|
|
* 0: normal
|
|
* 1: nested
|
|
*/
|
|
enum dentry_d_lock_class
|
|
{
|
|
DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
|
|
DENTRY_D_LOCK_NESTED
|
|
};
|
|
|
|
struct dentry_operations {
|
|
int (*d_revalidate)(struct dentry *, unsigned int);
|
|
int (*d_weak_revalidate)(struct dentry *, unsigned int);
|
|
int (*d_hash)(const struct dentry *, struct qstr *);
|
|
int (*d_compare)(const struct dentry *, const struct dentry *,
|
|
unsigned int, const char *, const struct qstr *);
|
|
int (*d_delete)(const struct dentry *);
|
|
void (*d_release)(struct dentry *);
|
|
void (*d_prune)(struct dentry *);
|
|
void (*d_iput)(struct dentry *, struct inode *);
|
|
char *(*d_dname)(struct dentry *, char *, int);
|
|
struct vfsmount *(*d_automount)(struct path *);
|
|
int (*d_manage)(struct dentry *, bool);
|
|
} ____cacheline_aligned;
|
|
|
|
/*
|
|
* Locking rules for dentry_operations callbacks are to be found in
|
|
* Documentation/filesystems/Locking. Keep it updated!
|
|
*
|
|
* FUrther descriptions are found in Documentation/filesystems/vfs.txt.
|
|
* Keep it updated too!
|
|
*/
|
|
|
|
/* d_flags entries */
|
|
#define DCACHE_OP_HASH 0x00000001
|
|
#define DCACHE_OP_COMPARE 0x00000002
|
|
#define DCACHE_OP_REVALIDATE 0x00000004
|
|
#define DCACHE_OP_DELETE 0x00000008
|
|
#define DCACHE_OP_PRUNE 0x00000010
|
|
|
|
#define DCACHE_DISCONNECTED 0x00000020
|
|
/* 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 0x00000040 /* Recently used, don't discard. */
|
|
#define DCACHE_RCUACCESS 0x00000080 /* Entry has ever been RCU-visible */
|
|
|
|
#define DCACHE_CANT_MOUNT 0x00000100
|
|
#define DCACHE_GENOCIDE 0x00000200
|
|
#define DCACHE_SHRINK_LIST 0x00000400
|
|
|
|
#define DCACHE_OP_WEAK_REVALIDATE 0x00000800
|
|
|
|
#define DCACHE_NFSFS_RENAMED 0x00001000
|
|
/* this dentry has been "silly renamed" and has to be deleted on the last
|
|
* dput() */
|
|
#define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */
|
|
#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000
|
|
/* Parent inode is watched by some fsnotify listener */
|
|
|
|
#define DCACHE_DENTRY_KILLED 0x00008000
|
|
|
|
#define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */
|
|
#define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */
|
|
#define DCACHE_MANAGE_TRANSIT 0x00040000 /* manage transit from this dirent */
|
|
#define DCACHE_MANAGED_DENTRY \
|
|
(DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT)
|
|
|
|
#define DCACHE_LRU_LIST 0x00080000
|
|
|
|
#define DCACHE_ENTRY_TYPE 0x00700000
|
|
#define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry */
|
|
#define DCACHE_DIRECTORY_TYPE 0x00100000 /* Normal directory */
|
|
#define DCACHE_AUTODIR_TYPE 0x00200000 /* Lookupless directory (presumed automount) */
|
|
#define DCACHE_SYMLINK_TYPE 0x00300000 /* Symlink */
|
|
#define DCACHE_FILE_TYPE 0x00400000 /* Other file type */
|
|
|
|
#define DCACHE_MAY_FREE 0x00800000
|
|
|
|
extern seqlock_t rename_lock;
|
|
|
|
/*
|
|
* 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 int d_instantiate_no_diralias(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 struct dentry * d_obtain_root(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 void d_invalidate(struct dentry *);
|
|
|
|
/* only used at mount-time */
|
|
extern struct dentry * d_make_root(struct inode *);
|
|
|
|
/* <clickety>-<click> the ramfs-type tree */
|
|
extern void d_genocide(struct dentry *);
|
|
|
|
extern void d_tmpfile(struct dentry *, struct inode *);
|
|
|
|
extern struct dentry *d_find_alias(struct inode *);
|
|
extern void d_prune_aliases(struct inode *);
|
|
|
|
/* test whether we have any submounts in a subdir tree */
|
|
extern int have_submounts(struct dentry *);
|
|
|
|
/*
|
|
* 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 void d_exchange(struct dentry *, struct dentry *);
|
|
extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
|
|
|
|
/* appendix may either be NULL or be used for transname suffixes */
|
|
extern struct dentry *d_lookup(const struct dentry *, const struct qstr *);
|
|
extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
|
|
extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
|
|
extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
|
|
const struct qstr *name, unsigned *seq);
|
|
|
|
static inline unsigned d_count(const struct dentry *dentry)
|
|
{
|
|
return dentry->d_lockref.count;
|
|
}
|
|
|
|
/* validate "insecure" dentry pointer */
|
|
extern int d_validate(struct dentry *, struct dentry *);
|
|
|
|
/*
|
|
* helper function for dentry_operations.d_dname() members
|
|
*/
|
|
extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
|
|
extern char *simple_dname(struct dentry *, char *, int);
|
|
|
|
extern char *__d_path(const struct path *, const struct path *, char *, int);
|
|
extern char *d_absolute_path(const struct path *, char *, int);
|
|
extern char *d_path(const struct path *, char *, int);
|
|
extern char *dentry_path_raw(struct dentry *, char *, int);
|
|
extern char *dentry_path(struct dentry *, char *, int);
|
|
|
|
/* Allocation counts.. */
|
|
|
|
/**
|
|
* dget, dget_dlock - get a reference to a dentry
|
|
* @dentry: dentry to get a reference to
|
|
*
|
|
* Given a dentry or %NULL pointer increment the reference count
|
|
* if appropriate and return the dentry. A dentry will not be
|
|
* destroyed when it has references.
|
|
*/
|
|
static inline struct dentry *dget_dlock(struct dentry *dentry)
|
|
{
|
|
if (dentry)
|
|
dentry->d_lockref.count++;
|
|
return dentry;
|
|
}
|
|
|
|
static inline struct dentry *dget(struct dentry *dentry)
|
|
{
|
|
if (dentry)
|
|
lockref_get(&dentry->d_lockref);
|
|
return dentry;
|
|
}
|
|
|
|
extern struct dentry *dget_parent(struct dentry *dentry);
|
|
|
|
/**
|
|
* d_unhashed - is dentry hashed
|
|
* @dentry: entry to check
|
|
*
|
|
* Returns true if the dentry passed is not currently hashed.
|
|
*/
|
|
|
|
static inline int d_unhashed(const struct dentry *dentry)
|
|
{
|
|
return hlist_bl_unhashed(&dentry->d_hash);
|
|
}
|
|
|
|
static inline int d_unlinked(const struct dentry *dentry)
|
|
{
|
|
return d_unhashed(dentry) && !IS_ROOT(dentry);
|
|
}
|
|
|
|
static inline int cant_mount(const struct dentry *dentry)
|
|
{
|
|
return (dentry->d_flags & DCACHE_CANT_MOUNT);
|
|
}
|
|
|
|
static inline void dont_mount(struct dentry *dentry)
|
|
{
|
|
spin_lock(&dentry->d_lock);
|
|
dentry->d_flags |= DCACHE_CANT_MOUNT;
|
|
spin_unlock(&dentry->d_lock);
|
|
}
|
|
|
|
extern void dput(struct dentry *);
|
|
|
|
static inline bool d_managed(const struct dentry *dentry)
|
|
{
|
|
return dentry->d_flags & DCACHE_MANAGED_DENTRY;
|
|
}
|
|
|
|
static inline bool d_mountpoint(const struct dentry *dentry)
|
|
{
|
|
return dentry->d_flags & DCACHE_MOUNTED;
|
|
}
|
|
|
|
/*
|
|
* Directory cache entry type accessor functions.
|
|
*/
|
|
static inline void __d_set_type(struct dentry *dentry, unsigned type)
|
|
{
|
|
dentry->d_flags = (dentry->d_flags & ~DCACHE_ENTRY_TYPE) | type;
|
|
}
|
|
|
|
static inline void __d_clear_type(struct dentry *dentry)
|
|
{
|
|
__d_set_type(dentry, DCACHE_MISS_TYPE);
|
|
}
|
|
|
|
static inline void d_set_type(struct dentry *dentry, unsigned type)
|
|
{
|
|
spin_lock(&dentry->d_lock);
|
|
__d_set_type(dentry, type);
|
|
spin_unlock(&dentry->d_lock);
|
|
}
|
|
|
|
static inline unsigned __d_entry_type(const struct dentry *dentry)
|
|
{
|
|
return dentry->d_flags & DCACHE_ENTRY_TYPE;
|
|
}
|
|
|
|
static inline bool d_can_lookup(const struct dentry *dentry)
|
|
{
|
|
return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
|
|
}
|
|
|
|
static inline bool d_is_autodir(const struct dentry *dentry)
|
|
{
|
|
return __d_entry_type(dentry) == DCACHE_AUTODIR_TYPE;
|
|
}
|
|
|
|
static inline bool d_is_dir(const struct dentry *dentry)
|
|
{
|
|
return d_can_lookup(dentry) || d_is_autodir(dentry);
|
|
}
|
|
|
|
static inline bool d_is_symlink(const struct dentry *dentry)
|
|
{
|
|
return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
|
|
}
|
|
|
|
static inline bool d_is_file(const struct dentry *dentry)
|
|
{
|
|
return __d_entry_type(dentry) == DCACHE_FILE_TYPE;
|
|
}
|
|
|
|
static inline bool d_is_negative(const struct dentry *dentry)
|
|
{
|
|
return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
|
|
}
|
|
|
|
static inline bool d_is_positive(const struct dentry *dentry)
|
|
{
|
|
return !d_is_negative(dentry);
|
|
}
|
|
|
|
extern int sysctl_vfs_cache_pressure;
|
|
|
|
static inline unsigned long vfs_pressure_ratio(unsigned long val)
|
|
{
|
|
return mult_frac(val, sysctl_vfs_cache_pressure, 100);
|
|
}
|
|
#endif /* __LINUX_DCACHE_H */
|