283 lines
7.0 KiB
C
283 lines
7.0 KiB
C
/*
|
|
* 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 const int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
|
|
|
|
static DEFINE_SPINLOCK(bitmap_lock);
|
|
|
|
static unsigned long count_free(struct buffer_head *map[], unsigned numblocks, __u32 numbits)
|
|
{
|
|
unsigned i, j, sum = 0;
|
|
struct buffer_head *bh;
|
|
|
|
for (i=0; i<numblocks-1; i++) {
|
|
if (!(bh=map[i]))
|
|
return(0);
|
|
for (j=0; j<bh->b_size; j++)
|
|
sum += nibblemap[bh->b_data[j] & 0xf]
|
|
+ nibblemap[(bh->b_data[j]>>4) & 0xf];
|
|
}
|
|
|
|
if (numblocks==0 || !(bh=map[numblocks-1]))
|
|
return(0);
|
|
i = ((numbits - (numblocks-1) * bh->b_size * 8) / 16) * 2;
|
|
for (j=0; j<i; j++) {
|
|
sum += nibblemap[bh->b_data[j] & 0xf]
|
|
+ nibblemap[(bh->b_data[j]>>4) & 0xf];
|
|
}
|
|
|
|
i = numbits%16;
|
|
if (i!=0) {
|
|
i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1);
|
|
sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf];
|
|
sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf];
|
|
}
|
|
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 minix_sb_info *sbi)
|
|
{
|
|
return (count_free(sbi->s_zmap, sbi->s_zmap_blocks,
|
|
sbi->s_nzones - sbi->s_firstdatazone + 1)
|
|
<< 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");
|
|
goto out;
|
|
}
|
|
bit = ino & ((1<<k) - 1);
|
|
ino >>= k;
|
|
if (ino >= sbi->s_imap_blocks) {
|
|
printk("minix_free_inode: nonexistent imap in superblock\n");
|
|
goto out;
|
|
}
|
|
|
|
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);
|
|
out:
|
|
clear_inode(inode); /* clear in-memory copy */
|
|
}
|
|
|
|
struct inode * minix_new_inode(const struct inode * dir, 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->i_uid = current_fsuid();
|
|
inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current_fsgid();
|
|
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 minix_sb_info *sbi)
|
|
{
|
|
return count_free(sbi->s_imap, sbi->s_imap_blocks, sbi->s_ninodes + 1);
|
|
}
|