282 строки
6.8 KiB
C
282 строки
6.8 KiB
C
/*
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* linux/fs/minix/bitmap.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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/*
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* Modified for 680x0 by Hamish Macdonald
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* Fixed for 680x0 by Andreas Schwab
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*/
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/* bitmap.c contains the code that handles the inode and block bitmaps */
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#include "minix.h"
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#include <linux/smp_lock.h>
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#include <linux/buffer_head.h>
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#include <linux/bitops.h>
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#include <linux/sched.h>
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static int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
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static unsigned long count_free(struct buffer_head *map[], unsigned numblocks, __u32 numbits)
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{
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unsigned i, j, sum = 0;
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struct buffer_head *bh;
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for (i=0; i<numblocks-1; i++) {
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if (!(bh=map[i]))
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return(0);
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for (j=0; j<bh->b_size; j++)
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sum += nibblemap[bh->b_data[j] & 0xf]
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+ nibblemap[(bh->b_data[j]>>4) & 0xf];
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}
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if (numblocks==0 || !(bh=map[numblocks-1]))
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return(0);
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i = ((numbits - (numblocks-1) * bh->b_size * 8) / 16) * 2;
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for (j=0; j<i; j++) {
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sum += nibblemap[bh->b_data[j] & 0xf]
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+ nibblemap[(bh->b_data[j]>>4) & 0xf];
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}
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i = numbits%16;
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if (i!=0) {
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i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1);
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sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf];
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sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf];
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}
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return(sum);
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}
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void minix_free_block(struct inode *inode, unsigned long block)
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{
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struct super_block *sb = inode->i_sb;
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struct minix_sb_info *sbi = minix_sb(sb);
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struct buffer_head *bh;
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int k = sb->s_blocksize_bits + 3;
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unsigned long bit, zone;
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if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
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printk("Trying to free block not in datazone\n");
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return;
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}
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zone = block - sbi->s_firstdatazone + 1;
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bit = zone & ((1<<k) - 1);
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zone >>= k;
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if (zone >= sbi->s_zmap_blocks) {
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printk("minix_free_block: nonexistent bitmap buffer\n");
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return;
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}
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bh = sbi->s_zmap[zone];
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lock_kernel();
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if (!minix_test_and_clear_bit(bit, bh->b_data))
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printk("minix_free_block (%s:%lu): bit already cleared\n",
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sb->s_id, block);
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unlock_kernel();
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mark_buffer_dirty(bh);
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return;
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}
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int minix_new_block(struct inode * inode)
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{
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struct minix_sb_info *sbi = minix_sb(inode->i_sb);
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int bits_per_zone = 8 * inode->i_sb->s_blocksize;
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int i;
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for (i = 0; i < sbi->s_zmap_blocks; i++) {
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struct buffer_head *bh = sbi->s_zmap[i];
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int j;
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lock_kernel();
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j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
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if (j < bits_per_zone) {
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minix_set_bit(j, bh->b_data);
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unlock_kernel();
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mark_buffer_dirty(bh);
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j += i * bits_per_zone + sbi->s_firstdatazone-1;
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if (j < sbi->s_firstdatazone || j >= sbi->s_nzones)
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break;
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return j;
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}
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unlock_kernel();
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}
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return 0;
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}
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unsigned long minix_count_free_blocks(struct minix_sb_info *sbi)
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{
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return (count_free(sbi->s_zmap, sbi->s_zmap_blocks,
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sbi->s_nzones - sbi->s_firstdatazone + 1)
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<< sbi->s_log_zone_size);
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}
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struct minix_inode *
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minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
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{
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int block;
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struct minix_sb_info *sbi = minix_sb(sb);
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struct minix_inode *p;
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if (!ino || ino > sbi->s_ninodes) {
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printk("Bad inode number on dev %s: %ld is out of range\n",
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sb->s_id, (long)ino);
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return NULL;
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}
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ino--;
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block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
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ino / MINIX_INODES_PER_BLOCK;
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*bh = sb_bread(sb, block);
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if (!*bh) {
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printk("Unable to read inode block\n");
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return NULL;
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}
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p = (void *)(*bh)->b_data;
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return p + ino % MINIX_INODES_PER_BLOCK;
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}
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struct minix2_inode *
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minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
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{
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int block;
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struct minix_sb_info *sbi = minix_sb(sb);
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struct minix2_inode *p;
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int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);
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*bh = NULL;
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if (!ino || ino > sbi->s_ninodes) {
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printk("Bad inode number on dev %s: %ld is out of range\n",
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sb->s_id, (long)ino);
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return NULL;
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}
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ino--;
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block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
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ino / minix2_inodes_per_block;
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*bh = sb_bread(sb, block);
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if (!*bh) {
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printk("Unable to read inode block\n");
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return NULL;
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}
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p = (void *)(*bh)->b_data;
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return p + ino % minix2_inodes_per_block;
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}
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/* Clear the link count and mode of a deleted inode on disk. */
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static void minix_clear_inode(struct inode *inode)
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{
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struct buffer_head *bh = NULL;
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if (INODE_VERSION(inode) == MINIX_V1) {
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struct minix_inode *raw_inode;
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raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
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if (raw_inode) {
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raw_inode->i_nlinks = 0;
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raw_inode->i_mode = 0;
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}
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} else {
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struct minix2_inode *raw_inode;
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raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
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if (raw_inode) {
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raw_inode->i_nlinks = 0;
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raw_inode->i_mode = 0;
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}
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}
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if (bh) {
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mark_buffer_dirty(bh);
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brelse (bh);
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}
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}
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void minix_free_inode(struct inode * inode)
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{
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struct super_block *sb = inode->i_sb;
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struct minix_sb_info *sbi = minix_sb(inode->i_sb);
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struct buffer_head *bh;
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int k = sb->s_blocksize_bits + 3;
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unsigned long ino, bit;
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ino = inode->i_ino;
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if (ino < 1 || ino > sbi->s_ninodes) {
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printk("minix_free_inode: inode 0 or nonexistent inode\n");
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goto out;
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}
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bit = ino & ((1<<k) - 1);
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ino >>= k;
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if (ino >= sbi->s_imap_blocks) {
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printk("minix_free_inode: nonexistent imap in superblock\n");
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goto out;
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}
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minix_clear_inode(inode); /* clear on-disk copy */
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bh = sbi->s_imap[ino];
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lock_kernel();
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if (!minix_test_and_clear_bit(bit, bh->b_data))
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printk("minix_free_inode: bit %lu already cleared\n", bit);
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unlock_kernel();
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mark_buffer_dirty(bh);
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out:
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clear_inode(inode); /* clear in-memory copy */
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}
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struct inode * minix_new_inode(const struct inode * dir, int * error)
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{
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struct super_block *sb = dir->i_sb;
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struct minix_sb_info *sbi = minix_sb(sb);
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struct inode *inode = new_inode(sb);
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struct buffer_head * bh;
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int bits_per_zone = 8 * sb->s_blocksize;
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unsigned long j;
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int i;
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if (!inode) {
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*error = -ENOMEM;
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return NULL;
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}
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j = bits_per_zone;
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bh = NULL;
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*error = -ENOSPC;
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lock_kernel();
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for (i = 0; i < sbi->s_imap_blocks; i++) {
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bh = sbi->s_imap[i];
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j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
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if (j < bits_per_zone)
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break;
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}
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if (!bh || j >= bits_per_zone) {
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unlock_kernel();
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iput(inode);
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return NULL;
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}
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if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */
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unlock_kernel();
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printk("minix_new_inode: bit already set\n");
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iput(inode);
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return NULL;
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}
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unlock_kernel();
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mark_buffer_dirty(bh);
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j += i * bits_per_zone;
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if (!j || j > sbi->s_ninodes) {
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iput(inode);
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return NULL;
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}
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inode->i_uid = current->fsuid;
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inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
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inode->i_ino = j;
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
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inode->i_blocks = 0;
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memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u));
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insert_inode_hash(inode);
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mark_inode_dirty(inode);
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*error = 0;
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return inode;
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}
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unsigned long minix_count_free_inodes(struct minix_sb_info *sbi)
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{
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return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1);
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}
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