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fs/minix/bitmap.c
6.39 KB
1da177e4c
Linux-2.6.12-rc2
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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/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/bitops.h>
static int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
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<BLOCK_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)*BLOCK_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, int block)
{
struct super_block * sb = inode->i_sb;
struct minix_sb_info * sbi = minix_sb(sb);
struct buffer_head * bh;
unsigned int bit,zone;
if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
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printk("Trying to free block not in datazone
");
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return;
}
zone = block - sbi->s_firstdatazone + 1;
bit = zone & 8191;
zone >>= 13;
if (zone >= sbi->s_zmap_blocks) {
printk("minix_free_block: nonexistent bitmap buffer
");
return;
}
bh = sbi->s_zmap[zone];
lock_kernel();
if (!minix_test_and_clear_bit(bit,bh->b_data))
printk("free_block (%s:%d): bit already cleared
",
sb->s_id, block);
unlock_kernel();
mark_buffer_dirty(bh);
return;
}
int minix_new_block(struct inode * inode)
{
struct minix_sb_info *sbi = minix_sb(inode->i_sb);
int i;
for (i = 0; i < sbi->s_zmap_blocks; i++) {
struct buffer_head *bh = sbi->s_zmap[i];
int j;
lock_kernel();
if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192) {
minix_set_bit(j,bh->b_data);
unlock_kernel();
mark_buffer_dirty(bh);
j += i*8192 + sbi->s_firstdatazone-1;
if (j < sbi->s_firstdatazone || j >= sbi->s_nzones)
break;
return j;
}
unlock_kernel();
}
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
",
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) {
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printk("Unable to read inode block
");
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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;
*bh = NULL;
if (!ino || ino > sbi->s_ninodes) {
printk("Bad inode number on dev %s: %ld is out of range
",
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) {
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printk("Unable to read inode block
");
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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 minix_sb_info *sbi = minix_sb(inode->i_sb);
struct buffer_head * bh;
unsigned long ino;
ino = inode->i_ino;
if (ino < 1 || ino > sbi->s_ninodes) {
printk("minix_free_inode: inode 0 or nonexistent inode
");
goto out;
}
if ((ino >> 13) >= sbi->s_imap_blocks) {
printk("minix_free_inode: nonexistent imap in superblock
");
goto out;
}
minix_clear_inode(inode); /* clear on-disk copy */
bh = sbi->s_imap[ino >> 13];
lock_kernel();
if (!minix_test_and_clear_bit(ino & 8191, bh->b_data))
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printk("minix_free_inode: bit %lu already cleared
", ino);
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unlock_kernel();
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 i,j;
if (!inode) {
*error = -ENOMEM;
return NULL;
}
j = 8192;
bh = NULL;
*error = -ENOSPC;
lock_kernel();
for (i = 0; i < sbi->s_imap_blocks; i++) {
bh = sbi->s_imap[i];
if ((j = minix_find_first_zero_bit(bh->b_data, 8192)) < 8192)
break;
}
if (!bh || j >= 8192) {
unlock_kernel();
iput(inode);
return NULL;
}
if (minix_test_and_set_bit(j,bh->b_data)) { /* shouldn't happen */
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printk("new_inode: bit already set
");
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unlock_kernel();
iput(inode);
return NULL;
}
unlock_kernel();
mark_buffer_dirty(bh);
j += i*8192;
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 = inode->i_blksize = 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);
}
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