112 lines
3.2 KiB
C
112 lines
3.2 KiB
C
#include "fs.h"
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#include <string.h>
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#include <minix/com.h>
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#include <assert.h>
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#include <minix/u64.h>
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#include "buf.h"
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#include "inode.h"
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#include "super.h"
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#include "const.h"
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/*===========================================================================*
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* count_free_bits *
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*===========================================================================*/
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PUBLIC bit_t count_free_bits(sp, map)
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struct super_block *sp; /* the filesystem to allocate from */
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int map; /* IMAP (inode map) or ZMAP (zone map) */
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{
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/* Allocate a bit from a bit map and return its bit number. */
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block_t start_block; /* first bit block */
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block_t block;
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bit_t map_bits; /* how many bits are there in the bit map? */
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short bit_blocks; /* how many blocks are there in the bit map? */
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bit_t origin; /* number of bit to start searching at */
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unsigned word, bcount;
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struct buf *bp;
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bitchunk_t *wptr, *wlim, k;
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bit_t i, b;
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bit_t free_bits;
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assert(sp != NULL);
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if (map == IMAP) {
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start_block = START_BLOCK;
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map_bits = (bit_t) (sp->s_ninodes + 1);
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bit_blocks = sp->s_imap_blocks;
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origin = sp->s_isearch;
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} else {
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start_block = START_BLOCK + sp->s_imap_blocks;
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map_bits = (bit_t) (sp->s_zones - (sp->s_firstdatazone - 1));
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bit_blocks = sp->s_zmap_blocks;
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origin = sp->s_zsearch;
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}
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/* Figure out where to start the bit search (depends on 'origin'). */
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if (origin >= map_bits) origin = 0; /* for robustness */
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free_bits = 0;
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/* Locate the starting place. */
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block = (block_t) (origin / FS_BITS_PER_BLOCK(sp->s_block_size));
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word = (origin % FS_BITS_PER_BLOCK(sp->s_block_size)) / FS_BITCHUNK_BITS;
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/* Iterate over all blocks plus one, because we start in the middle. */
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bcount = bit_blocks;
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do {
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bp = get_block(sp->s_dev, start_block + block, NORMAL);
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assert(bp);
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wlim = &bp->b_bitmap[FS_BITMAP_CHUNKS(sp->s_block_size)];
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/* Iterate over the words in block. */
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for (wptr = &bp->b_bitmap[word]; wptr < wlim; wptr++) {
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/* Does this word contain a free bit? */
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if (*wptr == (bitchunk_t) ~0) continue;
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k = (bitchunk_t) conv4(sp->s_native, (int) *wptr);
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for (i = 0; i < 8*sizeof(k); ++i) {
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/* Bit number from the start of the bit map. */
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b = ((bit_t) block * FS_BITS_PER_BLOCK(sp->s_block_size))
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+ (wptr - &bp->b_bitmap[0]) * FS_BITCHUNK_BITS
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+ i;
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/* Don't count bits beyond the end of the map. */
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if (b >= map_bits) {
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break;
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}
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if ((k & (1 << i)) == 0) {
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free_bits++;
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}
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}
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if (b >= map_bits) break;
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}
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put_block(bp, MAP_BLOCK);
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++block;
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word = 0;
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} while (--bcount > 0);
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return free_bits; /* no bit could be allocated */
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}
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/*===========================================================================*
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* blockstats *
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*===========================================================================*/
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PUBLIC void blockstats(u32_t *blocks, u32_t *free, u32_t *used)
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{
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struct super_block *sp;
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int scale;
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sp = get_super(fs_dev);
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assert(sp);
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scale = sp->s_log_zone_size;
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*blocks = sp->s_zones << scale;
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*free = count_free_bits(sp, ZMAP) << scale;
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*used = *blocks - *free;
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return;
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}
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