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/* bitmap.c contains the code that handles the inode and block bitmaps */
#include <string.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#define clear_block(addr) \
__asm__("cld\n\t" \
"rep\n\t" \
"stosl" \
::"a" (0),"c" (BLOCK_SIZE/4),"D" ((long) (addr)):"cx","di")
#define set_bit(nr,addr) ({\
register int res __asm__("ax"); \
__asm__("btsl %2,%3\n\tsetb %%al":"=a" (res):"0" (0),"r" (nr),"m" (*(addr))); \
res;})
#define clear_bit(nr,addr) ({\
register int res __asm__("ax"); \
__asm__("btrl %2,%3\n\tsetnb %%al":"=a" (res):"0" (0),"r" (nr),"m" (*(addr))); \
res;})
#define find_first_zero(addr) ({ \
int __res; \
__asm__("cld\n" \
"1:\tlodsl\n\t" \
"notl %%eax\n\t" \
"bsfl %%eax,%%edx\n\t" \
"je 2f\n\t" \
"addl %%edx,%%ecx\n\t" \
"jmp 3f\n" \
"2:\taddl $32,%%ecx\n\t" \
"cmpl $8192,%%ecx\n\t" \
"jl 1b\n" \
"3:" \
:"=c" (__res):"c" (0),"S" (addr):"ax","dx","si"); \
__res;})
void free_block(int dev, int block)
{
struct super_block * sb;
struct buffer_head * bh;
if (!(sb = get_super(dev)))
panic("trying to free block on nonexistent device");
if (block < sb->s_firstdatazone || block >= sb->s_nzones)
panic("trying to free block not in datazone");
bh = get_hash_table(dev,block);
if (bh) {
if (bh->b_count != 1) {
printk("trying to free block (%04x:%d), count=%d\n",
dev,block,bh->b_count);
return;
}
bh->b_dirt=0;
bh->b_uptodate=0;
brelse(bh);
}
block -= sb->s_firstdatazone - 1 ;
if (clear_bit(block&8191,sb->s_zmap[block/8192]->b_data)) {
printk("block (%04x:%d) ",dev,block+sb->s_firstdatazone-1);
panic("free_block: bit already cleared");
}
sb->s_zmap[block/8192]->b_dirt = 1;
}
int new_block(int dev)
{
struct buffer_head * bh;
struct super_block * sb;
int i,j;
if (!(sb = get_super(dev)))
panic("trying to get new block from nonexistant device");
j = 8192;
for (i=0 ; i<8 ; i++)
if (bh=sb->s_zmap[i])
if ((j=find_first_zero(bh->b_data))<8192)
break;
if (i>=8 || !bh || j>=8192)
return 0;
if (set_bit(j,bh->b_data))
panic("new_block: bit already set");
bh->b_dirt = 1;
j += i*8192 + sb->s_firstdatazone-1;
if (j >= sb->s_nzones)
return 0;
if (!(bh=getblk(dev,j)))
panic("new_block: cannot get block");
if (bh->b_count != 1)
panic("new block: count is != 1");
clear_block(bh->b_data);
bh->b_uptodate = 1;
bh->b_dirt = 1;
brelse(bh);
return j;
}
void free_inode(struct m_inode * inode)
{
struct super_block * sb;
struct buffer_head * bh;
if (!inode)
return;
if (!inode->i_dev) {
memset(inode,0,sizeof(*inode));
return;
}
if (inode->i_count>1) {
printk("trying to free inode with count=%d\n",inode->i_count);
panic("free_inode");
}
if (inode->i_nlinks)
panic("trying to free inode with links");
if (!(sb = get_super(inode->i_dev)))
panic("trying to free inode on nonexistent device");
if (inode->i_num < 1 || inode->i_num > sb->s_ninodes)
panic("trying to free inode 0 or nonexistant inode");
if (!(bh=sb->s_imap[inode->i_num>>13]))
panic("nonexistent imap in superblock");
if (clear_bit(inode->i_num&8191,bh->b_data))
panic("free_inode: bit already cleared");
bh->b_dirt = 1;
memset(inode,0,sizeof(*inode));
}
struct m_inode * new_inode(int dev)
{
struct m_inode * inode;
struct super_block * sb;
struct buffer_head * bh;
int i,j;
if (!(inode=get_empty_inode()))
return NULL;
if (!(sb = get_super(dev)))
panic("new_inode with unknown device");
j = 8192;
for (i=0 ; i<8 ; i++)
if (bh=sb->s_imap[i])
if ((j=find_first_zero(bh->b_data))<8192)
break;
if (!bh || j >= 8192 || j+i*8192 > sb->s_ninodes) {
iput(inode);
return NULL;
}
if (set_bit(j,bh->b_data))
panic("new_inode: bit already set");
bh->b_dirt = 1;
inode->i_count=1;
inode->i_nlinks=1;
inode->i_dev=dev;
inode->i_dirt=1;
inode->i_num = j + i*8192;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
return inode;
}
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