path: root/fs/reiserfs/bitmap.c

/*
 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
 */
/* Reiserfs block (de)allocator, bitmap-based. */

#include <linux/time.h>
#include <linux/reiserfs_fs.h>
#include <linux/errno.h>
#include <linux/buffer_head.h>
#include <linux/kernel.h>
#include <linux/pagemap.h>
#include <linux/vmalloc.h>
#include <linux/reiserfs_fs_sb.h>
#include <linux/reiserfs_fs_i.h>
#include <linux/quotaops.h>

#define PREALLOCATION_SIZE 9

/* different reiserfs block allocator options */

#define SB_ALLOC_OPTS(s) (REISERFS_SB(s)->s_alloc_options.bits)

#define  _ALLOC_concentrating_formatted_nodes 0
#define  _ALLOC_displacing_large_files 1
#define  _ALLOC_displacing_new_packing_localities 2
#define  _ALLOC_old_hashed_relocation 3
#define  _ALLOC_new_hashed_relocation 4
#define  _ALLOC_skip_busy 5
#define  _ALLOC_displace_based_on_dirid 6
#define  _ALLOC_hashed_formatted_nodes 7
#define  _ALLOC_old_way 8
#define  _ALLOC_hundredth_slices 9
#define  _ALLOC_dirid_groups 10
#define  _ALLOC_oid_groups 11
#define  _ALLOC_packing_groups 12

#define  concentrating_formatted_nodes(s)	test_bit(_ALLOC_concentrating_formatted_nodes, &SB_ALLOC_OPTS(s))
#define  displacing_large_files(s)		test_bit(_ALLOC_displacing_large_files, &SB_ALLOC_OPTS(s))
#define  displacing_new_packing_localities(s)	test_bit(_ALLOC_displacing_new_packing_localities, &SB_ALLOC_OPTS(s))

#define SET_OPTION(optname) \
   do { \
	reiserfs_info(s, "block allocator option \"%s\" is set", #optname); \
	set_bit(_ALLOC_ ## optname , &SB_ALLOC_OPTS(s)); \
    } while(0)
#define TEST_OPTION(optname, s) \
    test_bit(_ALLOC_ ## optname , &SB_ALLOC_OPTS(s))

static inline void get_bit_address(struct super_block *s,
				   b_blocknr_t block,
				   unsigned int *bmap_nr,
				   unsigned int *offset)
{
	/* It is in the bitmap block number equal to the block
	 * number divided by the number of bits in a block. */
	*bmap_nr = block >> (s->s_blocksize_bits + 3);
	/* Within that bitmap block it is located at bit offset *offset. */
	*offset = block & ((s->s_blocksize << 3) - 1);
}

int is_reusable(struct super_block *s, b_blocknr_t block, int bit_value)
{
	unsigned int bmap, offset;
	unsigned int bmap_count = reiserfs_bmap_count(s);

	if (block == 0 || block >= SB_BLOCK_COUNT(s)) {
		reiserfs_error(s, "vs-4010",
			       "block number is out of range %lu (%u)",
			       block, SB_BLOCK_COUNT(s));
		return 0;
	}

	get_bit_address(s, block, &bmap, &offset);

	/* Old format filesystem? Unlikely, but the bitmaps are all up front so
	 * we need to account for it. */
	if (unlikely(test_bit(REISERFS_OLD_FORMAT,
			      &(REISERFS_SB(s)->s_properties)))) {
		b_blocknr_t bmap1 = REISERFS_SB(s)->s_sbh->b_blocknr + 1;
		if (block >= bmap1 &&
		    block <= bmap1 + bmap_count) {
			reiserfs_error(s, "vs-4019", "bitmap block %lu(%u) "
				       "can't be freed or reused",
				       block, bmap_count);
			return 0;
		}
	} else {
		if (offset == 0) {
			reiserfs_error(s, "vs-4020", "bitmap block %lu(%u) "
				       "can't be freed or reused",
				       block, bmap_count);
			<