Initial import

1 files changed, 579 insertions, 0 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
new file mode 100644
index 000000000..df334cbac
--- /dev/null
+++ b/include/linux/dcache.h
@@ -0,0 +1,579 @@
+#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 */
+	struct list_head d_child;	/* child of parent list */
+	struct list_head d_subdirs;	/* our children */
+	/*
+	 * d_alias and d_rcu can share memory
+	 */
+	union {
+		struct hlist_node d_alias;	/* inode alias list */
+	 	struct rcu_head d_rcu;
+	} d_u;
+};
+
+/*
+ * 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 (maybe fallthru to nowhere) */
+#define DCACHE_WHITEOUT_TYPE		0x00100000 /* Whiteout dentry (stop pathwalk) */
+#define DCACHE_DIRECTORY_TYPE		0x00200000 /* Normal directory */
+#define DCACHE_AUTODIR_TYPE		0x00300000 /* Lookupless directory (presumed automount) */
+#define DCACHE_REGULAR_TYPE		0x00400000 /* Regular file type (or fallthru to such) */
+#define DCACHE_SPECIAL_TYPE		0x00500000 /* Other file type (or fallthru to such) */
+#define DCACHE_SYMLINK_TYPE		0x00600000 /* Symlink (or fallthru to such) */
+
+#define DCACHE_MAY_FREE			0x00800000
+#define DCACHE_FALLTHRU			0x01000000 /* Fall through to lower layer */
+
+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 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;
+}
+
+/*
+ * 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 unsigned __d_entry_type(const struct dentry *dentry)
+{
+	unsigned type = READ_ONCE(dentry->d_flags);
+	smp_rmb();
+	return type & DCACHE_ENTRY_TYPE;
+}
+
+static inline bool d_is_miss(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
+}
+
+static inline bool d_is_whiteout(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_WHITEOUT_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_reg(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
+}
+
+static inline bool d_is_special(const struct dentry *dentry)
+{
+	return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
+}
+
+static inline bool d_is_file(const struct dentry *dentry)
+{
+	return d_is_reg(dentry) || d_is_special(dentry);
+}
+
+static inline bool d_is_negative(const struct dentry *dentry)
+{
+	// TODO: check d_is_whiteout(dentry) also.
+	return d_is_miss(dentry);
+}
+
+static inline bool d_is_positive(const struct dentry *dentry)
+{
+	return !d_is_negative(dentry);
+}
+
+/**
+ * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs)
+ * @dentry: The dentry in question
+ *
+ * Returns true if the dentry represents either an absent name or a name that
+ * doesn't map to an inode (ie. ->d_inode is NULL).  The dentry could represent
+ * a true miss, a whiteout that isn't represented by a 0,0 chardev or a
+ * fallthrough marker in an opaque directory.
+ *
+ * Note!  (1) This should be used *only* by a filesystem to examine its own
+ * dentries.  It should not be used to look at some other filesystem's
+ * dentries.  (2) It should also be used in combination with d_inode() to get
+ * the inode.  (3) The dentry may have something attached to ->d_lower and the
+ * type field of the flags may be set to something other than miss or whiteout.
+ */
+static inline bool d_really_is_negative(const struct dentry *dentry)
+{
+	return dentry->d_inode == NULL;
+}
+
+/**
+ * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs)
+ * @dentry: The dentry in question
+ *
+ * Returns true if the dentry represents a name that maps to an inode
+ * (ie. ->d_inode is not NULL).  The dentry might still represent a whiteout if
+ * that is represented on medium as a 0,0 chardev.
+ *
+ * Note!  (1) This should be used *only* by a filesystem to examine its own
+ * dentries.  It should not be used to look at some other filesystem's
+ * dentries.  (2) It should also be used in combination with d_inode() to get
+ * the inode.
+ */
+static inline bool d_really_is_positive(const struct dentry *dentry)
+{
+	return dentry->d_inode != NULL;
+}
+
+extern void d_set_fallthru(struct dentry *dentry);
+
+static inline bool d_is_fallthru(const struct dentry *dentry)
+{
+	return dentry->d_flags & DCACHE_FALLTHRU;
+}
+
+
+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);
+}
+
+/**
+ * d_inode - Get the actual inode of this dentry
+ * @dentry: The dentry to query
+ *
+ * This is the helper normal filesystems should use to get at their own inodes
+ * in their own dentries and ignore the layering superimposed upon them.
+ */
+static inline struct inode *d_inode(const struct dentry *dentry)
+{
+	return dentry->d_inode;
+}
+
+/**
+ * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE()
+ * @dentry: The dentry to query
+ *
+ * This is the helper normal filesystems should use to get at their own inodes
+ * in their own dentries and ignore the layering superimposed upon them.
+ */
+static inline struct inode *d_inode_rcu(const struct dentry *dentry)
+{
+	return ACCESS_ONCE(dentry->d_inode);
+}
+
+/**
+ * d_backing_inode - Get upper or lower inode we should be using
+ * @upper: The upper layer
+ *
+ * This is the helper that should be used to get at the inode that will be used
+ * if this dentry were to be opened as a file.  The inode may be on the upper
+ * dentry or it may be on a lower dentry pinned by the upper.
+ *
+ * Normal filesystems should not use this to access their own inodes.
+ */
+static inline struct inode *d_backing_inode(const struct dentry *upper)
+{
+	struct inode *inode = upper->d_inode;
+
+	return inode;
+}
+
+/**
+ * d_backing_dentry - Get upper or lower dentry we should be using
+ * @upper: The upper layer
+ *
+ * This is the helper that should be used to get the dentry of the inode that
+ * will be used if this dentry were opened as a file.  It may be the upper
+ * dentry or it may be a lower dentry pinned by the upper.
+ *
+ * Normal filesystems should not use this to access their own dentries.
+ */
+static inline struct dentry *d_backing_dentry(struct dentry *upper)
+{
+	return upper;
+}
+
+#endif	/* __LINUX_DCACHE_H */