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/*
* linux/fs/minix/bitmap.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* Modified for 680x0 by Hamish Macdonald
* Fixed for 680x0 by Andreas Schwab
*/
/* bitmap.c contains the code that handles the inode and block bitmaps */
#include "minix.h"
#include <linux/buffer_head.h>
#include <linux/bitops.h>
#include <linux/sched.h>
static DEFINE_SPINLOCK(bitmap_lock);
/*
* bitmap consists of blocks filled with 16bit words
* bit set == busy, bit clear == free
* endianness is a mess, but for counting zero bits it really doesn't matter...
*/
static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits)
{
__u32 sum = 0;
unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8);
while (blocks--) {
unsigned words = blocksize / 2;
__u16 *p = (__u16 *)(*map++)->b_data;
while (words--)
sum += 16 - hweight16(*p++);
}
return sum;
}
void minix_free_block(struct inode *inode, unsigned long block)
{
struct super_block *sb = inode->i_sb;
struct minix_sb_info *sbi = minix_sb(sb);
struct buffer_head *bh;
int k = sb->s_blocksize_bits + 3;
unsigned long bit, zone;
if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
printk("Trying to free block not in datazone\n");
return;
}
zone = block - sbi->s_firstdatazone + 1;
bit = zone & ((1<<k) - 1);
zone >>= k;
if (zone >= sbi->s_zmap_blocks) {
printk("minix_free_block: nonexistent bitmap buffer\n");
return;
}
bh = sbi->s_zmap[zone];
spin_lock(&bitmap_lock);
if (!minix_test_and_clear_bit(bit, bh->b_data))
printk("minix_free_block (%s:%lu): bit already cleared\n",
sb->s_id, block);
spin_unlock(&bitmap_lock);
mark_buffer_dirty(bh);
return;
}
int minix_new_block(struct inode * inode)
{
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
int bits_per_zone = 8 * inode->i_sb->s_blocksize;
int i;
for (i = 0; i < sbi->s_zmap_blocks; i++) {
struct buffer_head *bh = sbi->s_zmap[i];
int j;
spin_lock(&bitmap_lock);
j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
if (j < bits_per_zone) {
minix_set_bit(j, bh->b_data);
spin_unlock(&bitmap_lock);
mark_buffer_dirty(bh);
j += i * bits_per_zone + sbi->s_firstdatazone-1;
if (j < sbi->s_firstdatazone || j >= sbi->s_nzones)
break;
return j;
}
spin_unlock(&bitmap_lock);
}
return 0;
}
unsigned long minix_count_free_blocks(struct super_block *sb)
{
struct minix_sb_info *sbi = minix_sb(sb);
u32 bits = sbi->s_nzones - (sbi->s_firstdatazone + 1);
return (count_free(sbi->s_zmap, sb->s_blocksize, bits)
<< sbi->s_log_zone_size);
}
struct minix_inode *
minix_V1_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
{
int block;
struct minix_sb_info *sbi = minix_sb(sb);
struct minix_inode *p;
if (!ino || ino > sbi->s_ninodes) {
printk("Bad inode number on dev %s: %ld is out of range\n",
sb->s_id, (long)ino);
return NULL;
}
ino--;
block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
ino / MINIX_INODES_PER_BLOCK;
*bh = sb_bread(sb, block);
if (!*bh) {
printk("Unable to read inode block\n");
return NULL;
}
p = (void *)(*bh)->b_data;
return p + ino % MINIX_INODES_PER_BLOCK;
}
struct minix2_inode *
minix_V2_raw_inode(struct super_block *sb, ino_t ino, struct buffer_head **bh)
{
int block;
struct minix_sb_info *sbi = minix_sb(sb);
struct minix2_inode *p;
int minix2_inodes_per_block = sb->s_blocksize / sizeof(struct minix2_inode);
*bh = NULL;
if (!ino || ino > sbi->s_ninodes) {
printk("Bad inode number on dev %s: %ld is out of range\n",
sb->s_id, (long)ino);
return NULL;
}
ino--;
block = 2 + sbi->s_imap_blocks + sbi->s_zmap_blocks +
ino / minix2_inodes_per_block;
*bh = sb_bread(sb, block);
if (!*bh) {
printk("Unable to read inode block\n");
return NULL;
}
p = (void *)(*bh)->b_data;
return p + ino % minix2_inodes_per_block;
}
/* Clear the link count and mode of a deleted inode on disk. */
static void minix_clear_inode(struct inode *inode)
{
struct buffer_head *bh = NULL;
if (INODE_VERSION(inode) == MINIX_V1) {
struct minix_inode *raw_inode;
raw_inode = minix_V1_raw_inode(inode->i_sb, inode->i_ino, &bh);
if (raw_inode) {
raw_inode->i_nlinks = 0;
raw_inode->i_mode = 0;
}
} else {
struct minix2_inode *raw_inode;
raw_inode = minix_V2_raw_inode(inode->i_sb, inode->i_ino, &bh);
if (raw_inode) {
raw_inode->i_nlinks = 0;
raw_inode->i_mode = 0;
}
}
if (bh) {
mark_buffer_dirty(bh);
brelse (bh);
}
}
void minix_free_inode(struct inode * inode)
{
struct super_block *sb = inode->i_sb;
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
struct buffer_head *bh;
int k = sb->s_blocksize_bits + 3;
unsigned long ino, bit;
ino = inode->i_ino;
if (ino < 1 || ino > sbi->s_ninodes) {
printk("minix_free_inode: inode 0 or nonexistent inode\n");
return;
}
bit = ino & ((1<<k) - 1);
ino >>= k;
if (ino >= sbi->s_imap_blocks) {
printk("minix_free_inode: nonexistent imap in superblock\n");
return;
}
minix_clear_inode(inode); /* clear on-disk copy */
bh = sbi->s_imap[ino];
spin_lock(&bitmap_lock);
if (!minix_test_and_clear_bit(bit, bh->b_data))
printk("minix_free_inode: bit %lu already cleared\n", bit);
spin_unlock(&bitmap_lock);
mark_buffer_dirty(bh);
}
struct inode *minix_new_inode(const struct inode *dir, umode_t mode, int *error)
{
struct super_block *sb = dir->i_sb;
struct minix_sb_info *sbi = minix_sb(sb);
struct inode *inode = new_inode(sb);
struct buffer_head * bh;
int bits_per_zone = 8 * sb->s_blocksize;
unsigned long j;
int i;
if (!inode) {
*error = -ENOMEM;
return NULL;
}
j = bits_per_zone;
bh = NULL;
*error = -ENOSPC;
spin_lock(&bitmap_lock);
for (i = 0; i < sbi->s_imap_blocks; i++) {
bh = sbi->s_imap[i];
j = minix_find_first_zero_bit(bh->b_data, bits_per_zone);
if (j < bits_per_zone)
break;
}
if (!bh || j >= bits_per_zone) {
spin_unlock(&bitmap_lock);
iput(inode);
return NULL;
}
if (minix_test_and_set_bit(j, bh->b_data)) { /* shouldn't happen */
spin_unlock(&bitmap_lock);
printk("minix_new_inode: bit already set\n");
iput(inode);
return NULL;
}
spin_unlock(&bitmap_lock);
mark_buffer_dirty(bh);
j += i * bits_per_zone;
if (!j || j > sbi->s_ninodes) {
iput(inode);
return NULL;
}
inode_init_owner(inode, dir, mode);
inode->i_ino = j;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
inode->i_blocks = 0;
memset(&minix_i(inode)->u, 0, sizeof(minix_i(inode)->u));
insert_inode_hash(inode);
mark_inode_dirty(inode);
*error = 0;
return inode;
}
unsigned long minix_count_free_inodes(struct super_block *sb)
{
struct minix_sb_info *sbi = minix_sb(sb);
u32 bits = sbi->s_ninodes + 1;
return count_free(sbi->s_imap, sb->s_blocksize, bits);
}
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