include/linux/ufs_fs_sb.h


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38

/* 
 *  linux/include/linux/ufs_fs_sb.h
 *
 * Copyright (C) 1996
 * Adrian Rodriguez (adrian@franklins-tower.rutgers.edu)
 * Laboratory for Computer Science Research Computing Facility
 * Rutgers, The State University of New Jersey
 *
 * $Id: ufs_fs_sb.h,v 1.8 1998/05/06 12:04:40 jj Exp $
 *
 * Write support by Daniel Pirkl <daniel.pirkl@email.cz>
 */

#ifndef __LINUX_UFS_FS_SB_H
#define __LINUX_UFS_FS_SB_H


#define UFS_MAX_GROUP_LOADED 8
#define UFS_CGNO_EMPTY ((unsigned)-1)

struct ufs_sb_private_info;
struct ufs_cg_private_info;
struct ufs_csum;
#define UFS_MAXCSBUFS 31

struct ufs_sb_info {
	struct ufs_sb_private_info * s_uspi;	
	struct ufs_csum	* s_csp;
	unsigned s_bytesex;
	unsigned s_flags;
	struct buffer_head ** s_ucg;
	struct ufs_cg_private_info * s_ucpi[UFS_MAX_GROUP_LOADED]; 
	unsigned s_cgno[UFS_MAX_GROUP_LOADED];
	unsigned short s_cg_loaded;
	unsigned s_mount_opt;
};

#endif
/*
 * fs/sysfs/dir.c - sysfs core and dir operation implementation
 *
 * Copyright (c) 2001-3 Patrick Mochel
 * Copyright (c) 2007 SUSE Linux Products GmbH
 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
 *
 * This file is released under the GPLv2.
 *
 * Please see Documentation/filesystems/sysfs.txt for more information.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/namei.h>
#include <linux/idr.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/security.h>
#include <linux/hash.h>
#include "sysfs.h"

DEFINE_MUTEX(sysfs_mutex);
DEFINE_SPINLOCK(sysfs_assoc_lock);

#define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb);

static DEFINE_SPINLOCK(sysfs_ino_lock);
static DEFINE_IDA(sysfs_ino_ida);

/**
 *	sysfs_name_hash
 *	@ns:   Namespace tag to hash
 *	@name: Null terminated string to hash
 *
 *	Returns 31 bit hash of ns + name (so it fits in an off_t )
 */
static unsigned int sysfs_name_hash(const void *ns, const char *name)
{
	unsigned long hash = init_name_hash();
	unsigned int len = strlen(name);
	while (len--)
		hash = partial_name_hash(*name++, hash);
	hash = ( end_name_hash(hash) ^ hash_ptr( (void *)ns, 31 ) );
	hash &= 0x7fffffffU;
	/* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
	if (hash < 1)
		hash += 2;
	if (hash >= INT_MAX)
		hash = INT_MAX - 1;
	return hash;
}

static int sysfs_name_compare(unsigned int hash, const void *ns,
	const char *name, const struct sysfs_dirent *sd)
{
	if (hash != sd->s_hash)
		return hash - sd->s_hash;
	if (ns != sd->s_ns)
		return ns - sd->s_ns;
	return strcmp(name, sd->s_name);
}

static int sysfs_sd_compare(const struct sysfs_dirent *left,
			    const struct sysfs_dirent *right)
{
	return sysfs_name_compare(left->s_hash, left->s_ns, left->s_name,
				  right);
}

/**
 *	sysfs_link_subling - link sysfs_dirent into sibling rbtree
 *	@sd: sysfs_dirent of interest
 *
 *	Link @sd into its sibling rbtree which starts from
 *	sd->s_parent->s_dir.children.
 *
 *	Locking:
 *	mutex_lock(sysfs_mutex)
 *
 *	RETURNS:
 *	0 on susccess -EEXIST on failure.
 */
static int sysfs_link_sibling(struct sysfs_dirent *sd)
{
	struct rb_node **node = &sd->s_parent->s_dir.children.rb_node;
	struct rb_node *parent = NULL;

	while (*node) {
		struct sysfs_dirent *pos;
		int result;

		pos = to_sysfs_dirent(*node);
		parent = *node;
		result = sysfs_sd_compare(sd, pos);
		if (result < 0)
			node = &pos->s_rb.rb_left;
		else if (result > 0)
			node = &pos->s_rb.rb_right;
		else
			return -EEXIST;
	}
	/* add new node and rebalance the tree */
	rb_link_node(&sd->s_rb, parent, node);
	rb_insert_color(&sd->s_rb, &sd->s_parent->s_dir.children);
	return 0;
}

/**
 *	sysfs_unlink_sibling - unlink sysfs_dirent from sibling rbtree
 *	@sd: sysfs_dirent of interest
 *
 *	Unlink @sd from its sibling rbtree which starts from
 *	sd->s_parent->s_dir.children.
 *
 *	Locking:
 *	mutex_lock(sysfs_mutex)
 */
static void sysfs_unlink_sibling(struct sysfs_dirent *sd)
{
	rb_erase(&sd->s_rb, &sd->s_parent->s_dir.children);
}

/**
 *	sysfs_get_active - get an active reference to sysfs_dirent
 *	@sd: sysfs_dirent to get an active reference to
 *
 *	Get an active reference of @sd.  This function is noop if @sd
 *	is NULL.
 *
 *	RETURNS:
 *	Pointer to @sd on success, NULL on failure.
 */
struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
{
	if (unlikely(!sd))
		return NULL;

	while (1) {
		int v, t;

		v = atomic_read(&sd->s_active);
		if (unlikely(v < 0))
			return NULL;

		t = atomic_cmpxchg(&sd->s_active, v, v + 1);
		if (likely(t == v)) {
			rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
			return sd;
		}
		if (t < 0)
			return NULL;

		cpu_relax();
	}
}

/**
 *	sysfs_put_active - put an active reference to sysfs_dirent
 *	@sd: sysfs_dirent to put an active reference to
 *
 *	Put an active reference to @sd.  This function is noop if @sd
 *	is NULL.
 */
void sysfs_put_active(struct sysfs_dirent *sd)
{
	int v;

	if (unlikely(!sd))
		return;

	rwsem_release(&sd->dep_map, 1, _RET_IP_);
	v = atomic_dec_return(&sd->s_active);
	if (likely(v != SD_DEACTIVATED_BIAS))
		return;

	/* atomic_dec_return() is a mb(), we'll always see the updated
	 * sd->u.completion.
	 */
	complete(sd->u.completion);
}

/**