overlayfs: Implement splice-read

[linux-block.git] / fs / reiserfs / item_ops.c

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

#include <linux/time.h>
#include "reiserfs.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 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 | %u\n", sd_v1_mode(sd),
		       sd_v1_size(sd), sd_v1_nlink(sd),
		       sd_v1_first_direct_byte(sd),
		       sd_v1_mtime(sd));
	} else {
		struct stat_data *sd = (struct stat_data *)item;

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

static void sd_check_item(struct item_head *ih, char *item)
{
	/* unused */
}

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;
	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, "reiserfs-16100",
			 "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)
{
	/* unused */
}

static int direct_create_vi(struct virtual_node *vn,
			    struct virtual_item *vi,
			    int is_affected, int insert_size)
{
	vi->vi_index = 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, "reiserfs-16101",
			 "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;
}

/* 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, "reiserfs-16102", "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)
{
	/* unused */
}

static int indirect_create_vi(struct virtual_node *vn,
			      struct virtual_item *vi,
			      int is_affected, int insert_size)
{
	vi->vi_index = 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, "reiserfs-16103",
			 "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",
			 "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)
{
	if (le32_to_cpu(key->u.k_offset_v1.k_offset) == DOT_OFFSET)
		return 0;
	return 1;

}

static void direntry_print_item(struct item_head *ih, char *item)
{
	int i;
	int namelen;
	struct reiserfs_de_head *deh;
	char *name;
	static char namebuf[80];

	printk("\n # %-15s%-30s%-15s%-15s%-15s\n", "Name",
	       "Key of pointed object", "Hash", "Gen number", "Status");

	deh = (struct reiserfs_de_head *)item;

	for (i = 0; i < ih_entry_count(ih); i++, deh++) {
		namelen =
		    (i ? (deh_location(deh - 1)) : ih_item_len(ih)) -
		    deh_location(deh);
		name = item + deh_location(deh);
		if (name[namelen - 1] == 0)
			namelen = strlen(name);
		namebuf[0] = '"';
		if (namelen > sizeof(namebuf) - 3) {
			strncpy(namebuf + 1, name, sizeof(namebuf) - 3);
			namebuf[sizeof(namebuf) - 2] = '"';
			namebuf[sizeof(namebuf) - 1] = 0;
		} else {
			memcpy(namebuf + 1, name, namelen);
			namebuf[namelen + 1] = '"';
			namebuf[namelen + 2] = 0;
		}

		printk("%d:  %-15s%-15d%-15d%-15lld%-15lld(%s)\n",
		       i, namebuf,
		       deh_dir_id(deh), deh_objectid(deh),
		       GET_HASH_VALUE(deh_offset(deh)),
		       GET_GENERATION_NUMBER((deh_offset(deh))),
		       (de_hidden(deh)) ? "HIDDEN" : "VISIBLE");
	}
}

static void direntry_check_item(struct item_head *ih, char *item)
{
	int i;
	struct reiserfs_de_head *deh;

	/* unused */
	deh = (struct reiserfs_de_head *)item;
	for (i = 0; i < ih_entry_count(ih); i++, deh++) {
		;
	}
}

#define DIRENTRY_VI_FIRST_DIRENTRY_ITEM 1

/*
 * function returns old entry number in directory item in real node
 * using new entry number in virtual item in virtual node
 */
static inline int old_entry_num(int is_affected, int virtual_entry_num,
				int pos_in_item, int mode)
{
	if (mode == M_INSERT || mode == M_DELETE)
		return virtual_entry_num;

	if (!is_affected)
		/* cut or paste is applied to another item */
		return virtual_entry_num;

	if (virtual_entry_num < pos_in_item)
		return virtual_entry_num;

	if (mode == M_CUT)
		return virtual_entry_num + 1;

	RFALSE(mode != M_PASTE || virtual_entry_num == 0,
	       "vs-8015: old_entry_num: mode must be M_PASTE (mode = \'%c\'",
	       mode);

	return virtual_entry_num - 1;
}

/*
 * Create an array of sizes of directory entries for virtual
 * item. Return space used by an item. FIXME: no control over
 * consuming of space used by this item handler
 */
static int direntry_create_vi(struct virtual_node *vn,
			      struct virtual_item *vi,
			      int is_affected, int insert_size)
{
	struct direntry_uarea *dir_u = vi->vi_uarea;
	int i, j;
	int size = sizeof(struct direntry_uarea);
	struct reiserfs_de_head *deh;

	vi->vi_index = TYPE_DIRENTRY;

	BUG_ON(!(vi->vi_ih) || !vi->vi_item);

	dir_u->flags = 0;
	if (le_ih_k_offset(vi->vi_ih) == DOT_OFFSET)
		dir_u->flags |= DIRENTRY_VI_FIRST_DIRENTRY_ITEM;

	deh = (struct reiserfs_de_head *)(vi->vi_item);

	/* virtual directory item have this amount of entry after */
	dir_u->entry_count = ih_entry_count(vi->vi_ih) +
	    ((is_affected) ? ((vn->vn_mode == M_CUT) ? -1 :
			      (vn->vn_mode == M_PASTE ? 1 : 0)) : 0);

	for (i = 0; i < dir_u->entry_count; i++) {
		j = old_entry_num(is_affected, i, vn->vn_pos_in_item,
				  vn->vn_mode);
		dir_u->entry_sizes[i] =
		    (j ? deh_location(&deh[j - 1]) : ih_item_len(vi->vi_ih)) -
		    deh_location(&deh[j]) + DEH_SIZE;
	}

	size += (dir_u->entry_count * sizeof(short));

	/* set size of pasted entry */
	if (is_affected && vn->vn_mode == M_PASTE)
		dir_u->entry_sizes[vn->vn_pos_in_item] = insert_size;

#ifdef CONFIG_REISERFS_CHECK
	/* compare total size of entries with item length */
	{
		int k, l;

		l = 0;
		for (k = 0; k < dir_u->entry_count; k++)
			l += dir_u->entry_sizes[k];

		if (l + IH_SIZE != vi->vi_item_len +
		    ((is_affected
		      && (vn->vn_mode == M_PASTE
			  || vn->vn_mode == M_CUT)) ? insert_size : 0)) {
			reiserfs_panic(NULL, "vs-8025", "(mode==%c, "
				       "insert_size==%d), invalid length of "
				       "directory item",
				       vn->vn_mode, insert_size);
		}
	}
#endif

	return size;

}

/*
 * return number of entries which may fit into specified amount of
 * free space, or -1 if free space is not enough even for 1 entry
 */
static int direntry_check_left(struct virtual_item *vi, int free,
			       int start_skip, int end_skip)
{
	int i;
	int entries = 0;
	struct direntry_uarea *dir_u = vi->vi_uarea;

	for (i = start_skip; i < dir_u->entry_count - end_skip; i++) {
		/* i-th entry doesn't fit into the remaining free space */
		if (dir_u->entry_sizes[i] > free)
			break;

		free -= dir_u->entry_sizes[i];
		entries++;
	}

	if (entries == dir_u->entry_count) {
		reiserfs_panic(NULL, "item_ops-1",
			       "free space %d, entry_count %d", free,
			       dir_u->entry_count);
	}

	/* "." and ".." can not be separated from each other */
	if (start_skip == 0 && (dir_u->flags & DIRENTRY_VI_FIRST_DIRENTRY_ITEM)
	    && entries < 2)
		entries = 0;

	return entries ? : -1;
}

static int direntry_check_right(struct virtual_item *vi, int free)
{
	int i;
	int entries = 0;
	struct direntry_uarea *dir_u = vi->vi_uarea;

	for (i = dir_u->entry_count - 1; i >= 0; i--) {
		/* i-th entry doesn't fit into the remaining free space */
		if (dir_u->entry_sizes[i] > free)
			break;

		free -= dir_u->entry_sizes[i];
		entries++;
	}
	BUG_ON(entries == dir_u->entry_count);

	/* "." and ".." can not be separated from each other */
	if ((dir_u->flags & DIRENTRY_VI_FIRST_DIRENTRY_ITEM)
	    && entries > dir_u->entry_count - 2)
		entries = dir_u->entry_count - 2;

	return entries ? : -1;
}

/* sum of entry sizes between from-th and to-th entries including both edges */
static int direntry_part_size(struct virtual_item *vi, int first, int count)
{
	int i, retval;
	int from, to;
	struct direntry_uarea *dir_u = vi->vi_uarea;

	retval = 0;
	if (first == 0)
		from = 0;
	else
		from = dir_u->entry_count - count;
	to = from + count - 1;

	for (i = from; i <= to; i++)
		retval += dir_u->entry_sizes[i];

	return retval;
}

static int direntry_unit_num(struct virtual_item *vi)
{
	struct direntry_uarea *dir_u = vi->vi_uarea;

	return dir_u->entry_count;
}

static void direntry_print_vi(struct virtual_item *vi)
{
	int i;
	struct direntry_uarea *dir_u = vi->vi_uarea;

	reiserfs_warning(NULL, "reiserfs-16104",
			 "DIRENTRY, index %d, type 0x%x, %h, flags 0x%x",
			 vi->vi_index, vi->vi_type, vi->vi_ih, dir_u->flags);
	printk("%d entries: ", dir_u->entry_count);
	for (i = 0; i < dir_u->entry_count; i++)
		printk("%d ", dir_u->entry_sizes[i]);
	printk("\n");
}

static struct item_operations direntry_ops = {
	.bytes_number = direntry_bytes_number,
	.decrement_key = direntry_decrement_key,
	.is_left_mergeable = direntry_is_left_mergeable,
	.print_item = direntry_print_item,
	.check_item = direntry_check_item,

	.create_vi = direntry_create_vi,
	.check_left = direntry_check_left,
	.check_right = direntry_check_right,
	.part_size = direntry_part_size,
	.unit_num = direntry_unit_num,
	.print_vi = direntry_print_vi
};

/* Error catching functions to catch errors caused by incorrect item types. */
static int errcatch_bytes_number(struct item_head *ih, int block_size)
{
	reiserfs_warning(NULL, "green-16001",
			 "Invalid item type observed, run fsck ASAP");
	return 0;
}

static void errcatch_decrement_key(struct cpu_key *key)
{
	reiserfs_warning(NULL, "green-16002",
			 "Invalid item type observed, run fsck ASAP");
}

static int errcatch_is_left_mergeable(struct reiserfs_key *key,
				      unsigned long bsize)
{
	reiserfs_warning(NULL, "green-16003",
			 "Invalid item type observed, run fsck ASAP");
	return 0;
}

static void errcatch_print_item(struct item_head *ih, char *item)
{
	reiserfs_warning(NULL, "green-16004",
			 "Invalid item type observed, run fsck ASAP");
}

static void errcatch_check_item(struct item_head *ih, char *item)
{
	reiserfs_warning(NULL, "green-16005",
			 "Invalid item type observed, run fsck ASAP");
}

static int errcatch_create_vi(struct virtual_node *vn,
			      struct virtual_item *vi,
			      int is_affected, int insert_size)
{
	reiserfs_warning(NULL, "green-16006",
			 "Invalid item type observed, run fsck ASAP");
	/*
	 * We might return -1 here as well, but it won't help as
	 * create_virtual_node() from where this operation is called
	 * from is of return type void.
	 */
	return 0;
}

static int errcatch_check_left(struct virtual_item *vi, int free,
			       int start_skip, int end_skip)
{
	reiserfs_warning(NULL, "green-16007",
			 "Invalid item type observed, run fsck ASAP");
	return -1;
}

static int errcatch_check_right(struct virtual_item *vi, int free)
{
	reiserfs_warning(NULL, "green-16008",
			 "Invalid item type observed, run fsck ASAP");
	return -1;
}

static int errcatch_part_size(struct virtual_item *vi, int first, int count)
{
	reiserfs_warning(NULL, "green-16009",
			 "Invalid item type observed, run fsck ASAP");
	return 0;
}

static int errcatch_unit_num(struct virtual_item *vi)
{
	reiserfs_warning(NULL, "green-16010",
			 "Invalid item type observed, run fsck ASAP");
	return 0;
}

static void errcatch_print_vi(struct virtual_item *vi)
{
	reiserfs_warning(NULL, "green-16011",
			 "Invalid item type observed, run fsck ASAP");
}

static struct item_operations errcatch_ops = {
	.bytes_number = errcatch_bytes_number,
	.decrement_key = errcatch_decrement_key,
	.is_left_mergeable = errcatch_is_left_mergeable,
	.print_item = errcatch_print_item,
	.check_item = errcatch_check_item,

	.create_vi = errcatch_create_vi,
	.check_left = errcatch_check_left,
	.check_right = errcatch_check_right,
	.part_size = errcatch_part_size,
	.unit_num = errcatch_unit_num,
	.print_vi = errcatch_print_vi
};

#if ! (TYPE_STAT_DATA == 0 && TYPE_INDIRECT == 1 && TYPE_DIRECT == 2 && TYPE_DIRENTRY == 3)
#error Item types must use disk-format assigned values.
#endif

struct item_operations *item_ops[TYPE_ANY + 1] = {
	&stat_data_ops,
	&indirect_ops,
	&direct_ops,
	&direntry_ops,
	NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
	&errcatch_ops		/* This is to catch errors with invalid type (15th entry for TYPE_ANY) */
};