item_ops.c

linux 内核源代码

/*
 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
 */

#include <linux/time.h>
#include <linux/reiserfs_fs.h>

// this contains item handlers for old item types: sd, direct,
// indirect, directory

/* and where are the comments? how about saying where we can find an
   explanation of each item handler method? -Hans */

//////////////////////////////////////////////////////////////////////////////
// stat data functions
//
static int sd_bytes_number(struct item_head *ih, int block_size)
{
	return 0;
}

static void sd_decrement_key(struct cpu_key *key)
{
	key->on_disk_key.k_objectid--;
	set_cpu_key_k_type(key, TYPE_ANY);
	set_cpu_key_k_offset(key, (loff_t)(~0ULL >> 1));
}

static int sd_is_left_mergeable(struct reiserfs_key *key, unsigned long bsize)
{
	return 0;
}

static char *print_time(time_t t)
{
	static char timebuf[256];

	sprintf(timebuf, "%ld", t);
	return timebuf;
}

static void sd_print_item(struct item_head *ih, char *item)
{
	printk("\tmode | size | nlinks | first direct | mtime\n");
	if (stat_data_v1(ih)) {
		struct stat_data_v1 *sd = (struct stat_data_v1 *)item;

		printk("\t0%-6o | %6u | %2u | %d | %s\n", sd_v1_mode(sd),
		       sd_v1_size(sd), sd_v1_nlink(sd),
		       sd_v1_first_direct_byte(sd),
		       print_time(sd_v1_mtime(sd)));
	} else {
		struct stat_data *sd = (struct stat_data *)item;

		printk("\t0%-6o | %6Lu | %2u | %d | %s\n", sd_v2_mode(sd),
		       (unsigned long long)sd_v2_size(sd), sd_v2_nlink(sd),
		       sd_v2_rdev(sd), print_time(sd_v2_mtime(sd)));
	}
}

static void sd_check_item(struct item_head *ih, char *item)
{
	// FIXME: type something here!
}

static int sd_create_vi(struct virtual_node *vn,
			struct virtual_item *vi,
			int is_affected, int insert_size)
{
	vi->vi_index = TYPE_STAT_DATA;
	//vi->vi_type |= VI_TYPE_STAT_DATA;// not needed?
	return 0;
}

static int sd_check_left(struct virtual_item *vi, int free,
			 int start_skip, int end_skip)
{
	BUG_ON(start_skip || end_skip);
	return -1;
}

static int sd_check_right(struct virtual_item *vi, int free)
{
	return -1;
}

static int sd_part_size(struct virtual_item *vi, int first, int count)
{
	BUG_ON(count);
	return 0;
}

static int sd_unit_num(struct virtual_item *vi)
{
	return vi->vi_item_len - IH_SIZE;
}

static void sd_print_vi(struct virtual_item *vi)
{
	reiserfs_warning(NULL, "STATDATA, index %d, type 0x%x, %h",
			 vi->vi_index, vi->vi_type, vi->vi_ih);
}

static struct item_operations stat_data_ops = {
	.bytes_number = sd_bytes_number,
	.decrement_key = sd_decrement_key,
	.is_left_mergeable = sd_is_left_mergeable,
	.print_item = sd_print_item,
	.check_item = sd_check_item,

	.create_vi = sd_create_vi,
	.check_left = sd_check_left,
	.check_right = sd_check_right,
	.part_size = sd_part_size,
	.unit_num = sd_unit_num,
	.print_vi = sd_print_vi
};

//////////////////////////////////////////////////////////////////////////////
// direct item functions
//
static int direct_bytes_number(struct item_head *ih, int block_size)
{
	return ih_item_len(ih);
}

// FIXME: this should probably switch to indirect as well
static void direct_decrement_key(struct cpu_key *key)
{
	cpu_key_k_offset_dec(key);
	if (cpu_key_k_offset(key) == 0)
		set_cpu_key_k_type(key, TYPE_STAT_DATA);
}

static int direct_is_left_mergeable(struct reiserfs_key *key,
				    unsigned long bsize)
{
	int version = le_key_version(key);
	return ((le_key_k_offset(version, key) & (bsize - 1)) != 1);
}

static void direct_print_item(struct item_head *ih, char *item)
{
	int j = 0;

//    return;
	printk("\"");
	while (j < ih_item_len(ih))
		printk("%c", item[j++]);
	printk("\"\n");
}

static void direct_check_item(struct item_head *ih, char *item)
{
	// FIXME: type something here!
}

static int direct_create_vi(struct virtual_node *vn,
			    struct virtual_item *vi,
			    int is_affected, int insert_size)
{
	vi->vi_index = TYPE_DIRECT;
	//vi->vi_type |= VI_TYPE_DIRECT;
	return 0;
}

static int direct_check_left(struct virtual_item *vi, int free,
			     int start_skip, int end_skip)
{
	int bytes;

	bytes = free - free % 8;
	return bytes ? : -1;
}

static int direct_check_right(struct virtual_item *vi, int free)
{
	return direct_check_left(vi, free, 0, 0);
}

static int direct_part_size(struct virtual_item *vi, int first, int count)
{
	return count;
}

static int direct_unit_num(struct virtual_item *vi)
{
	return vi->vi_item_len - IH_SIZE;
}

static void direct_print_vi(struct virtual_item *vi)
{
	reiserfs_warning(NULL, "DIRECT, index %d, type 0x%x, %h",
			 vi->vi_index, vi->vi_type, vi->vi_ih);
}

static struct item_operations direct_ops = {
	.bytes_number = direct_bytes_number,
	.decrement_key = direct_decrement_key,
	.is_left_mergeable = direct_is_left_mergeable,
	.print_item = direct_print_item,
	.check_item = direct_check_item,

	.create_vi = direct_create_vi,
	.check_left = direct_check_left,
	.check_right = direct_check_right,
	.part_size = direct_part_size,
	.unit_num = direct_unit_num,
	.print_vi = direct_print_vi
};

//////////////////////////////////////////////////////////////////////////////
// indirect item functions
//

static int indirect_bytes_number(struct item_head *ih, int block_size)
{
	return ih_item_len(ih) / UNFM_P_SIZE * block_size;	//- get_ih_free_space (ih);
}

// decrease offset, if it becomes 0, change type to stat data
static void indirect_decrement_key(struct cpu_key *key)
{
	cpu_key_k_offset_dec(key);
	if (cpu_key_k_offset(key) == 0)
		set_cpu_key_k_type(key, TYPE_STAT_DATA);
}

// if it is not first item of the body, then it is mergeable
static int indirect_is_left_mergeable(struct reiserfs_key *key,
				      unsigned long bsize)
{
	int version = le_key_version(key);
	return (le_key_k_offset(version, key) != 1);
}

// printing of indirect item
static void start_new_sequence(__u32 * start, int *len, __u32 new)
{
	*start = new;
	*len = 1;
}

static int sequence_finished(__u32 start, int *len, __u32 new)
{
	if (start == INT_MAX)
		return 1;

	if (start == 0 && new == 0) {
		(*len)++;
		return 0;
	}
	if (start != 0 && (start + *len) == new) {
		(*len)++;
		return 0;
	}
	return 1;
}

static void print_sequence(__u32 start, int len)
{
	if (start == INT_MAX)
		return;

	if (len == 1)
		printk(" %d", start);
	else
		printk(" %d(%d)", start, len);
}

static void indirect_print_item(struct item_head *ih, char *item)
{
	int j;
	__le32 *unp;
	__u32 prev = INT_MAX;
	int num = 0;

	unp = (__le32 *) item;

	if (ih_item_len(ih) % UNFM_P_SIZE)
		reiserfs_warning(NULL, "indirect_print_item: invalid item len");

	printk("%d pointers\n[ ", (int)I_UNFM_NUM(ih));
	for (j = 0; j < I_UNFM_NUM(ih); j++) {
		if (sequence_finished(prev, &num, get_block_num(unp, j))) {
			print_sequence(prev, num);
			start_new_sequence(&prev, &num, get_block_num(unp, j));
		}
	}
	print_sequence(prev, num);
	printk("]\n");
}

static void indirect_check_item(struct item_head *ih, char *item)
{
	// FIXME: type something here!
}

static int indirect_create_vi(struct virtual_node *vn,
			      struct virtual_item *vi,
			      int is_affected, int insert_size)
{
	vi->vi_index = TYPE_INDIRECT;
	//vi->vi_type |= VI_TYPE_INDIRECT;
	return 0;
}

static int indirect_check_left(struct virtual_item *vi, int free,
			       int start_skip, int end_skip)
{
	int bytes;

	bytes = free - free % UNFM_P_SIZE;
	return bytes ? : -1;
}

static int indirect_check_right(struct virtual_item *vi, int free)
{
	return indirect_check_left(vi, free, 0, 0);
}

// return size in bytes of 'units' units. If first == 0 - calculate from the head (left), otherwise - from tail (right)
static int indirect_part_size(struct virtual_item *vi, int first, int units)
{
	// unit of indirect item is byte (yet)
	return units;
}

static int indirect_unit_num(struct virtual_item *vi)
{
	// unit of indirect item is byte (yet)
	return vi->vi_item_len - IH_SIZE;
}

static void indirect_print_vi(struct virtual_item *vi)
{
	reiserfs_warning(NULL, "INDIRECT, index %d, type 0x%x, %h",
			 vi->vi_index, vi->vi_type, vi->vi_ih);
}

static struct item_operations indirect_ops = {
	.bytes_number = indirect_bytes_number,
	.decrement_key = indirect_decrement_key,
	.is_left_mergeable = indirect_is_left_mergeable,
	.print_item = indirect_print_item,
	.check_item = indirect_check_item,

	.create_vi = indirect_create_vi,
	.check_left = indirect_check_left,
	.check_right = indirect_check_right,
	.part_size = indirect_part_size,
	.unit_num = indirect_unit_num,
	.print_vi = indirect_print_vi
};

//////////////////////////////////////////////////////////////////////////////
// direntry functions
//

static int direntry_bytes_number(struct item_head *ih, int block_size)
{
	reiserfs_warning(NULL, "vs-16090: direntry_bytes_number: "
			 "bytes number is asked for direntry");
	return 0;
}

static void direntry_decrement_key(struct cpu_key *key)
{
	cpu_key_k_offset_dec(key);
	if (cpu_key_k_offset(key) == 0)
		set_cpu_key_k_type(key, TYPE_STAT_DATA);
}

static int direntry_is_left_mergeable(struct reiserfs_key *key,
				      unsigned long bsize)
{