original development tree for Linux kernel GTP module; now long in mainline.
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/*
* linux/fs/sysv/ialloc.c
*
* minix/bitmap.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext/freelists.c
* Copyright (C) 1992 Remy Card (card@masi.ibp.fr)
*
* xenix/alloc.c
* Copyright (C) 1992 Doug Evans
*
* coh/alloc.c
* Copyright (C) 1993 Pascal Haible, Bruno Haible
*
* sysv/ialloc.c
* Copyright (C) 1993 Bruno Haible
*
* This file contains code for allocating/freeing inodes.
*/
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include "sysv.h"
/* We don't trust the value of
sb->sv_sbd2->s_tinode = *sb->sv_sb_total_free_inodes
but we nevertheless keep it up to date. */
/* An inode on disk is considered free if both i_mode == 0 and i_nlink == 0. */
/* return &sb->sv_sb_fic_inodes[i] = &sbd->s_inode[i]; */
static inline sysv_ino_t *
sv_sb_fic_inode(struct super_block * sb, unsigned int i)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
if (sbi->s_bh1 == sbi->s_bh2)
return &sbi->s_sb_fic_inodes[i];
else {
/* 512 byte Xenix FS */
unsigned int offset = offsetof(struct xenix_super_block, s_inode[i]);
if (offset < 512)
return (sysv_ino_t*)(sbi->s_sbd1 + offset);
else
return (sysv_ino_t*)(sbi->s_sbd2 + offset);
}
}
struct sysv_inode *
sysv_raw_inode(struct super_block *sb, unsigned ino, struct buffer_head **bh)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct sysv_inode *res;
int block = sbi->s_firstinodezone + sbi->s_block_base;
block += (ino-1) >> sbi->s_inodes_per_block_bits;
*bh = sb_bread(sb, block);
if (!*bh)
return NULL;
res = (struct sysv_inode *)(*bh)->b_data;
return res + ((ino-1) & sbi->s_inodes_per_block_1);
}
static int refill_free_cache(struct super_block *sb)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct buffer_head * bh;
struct sysv_inode * raw_inode;
int i = 0, ino;
ino = SYSV_ROOT_INO+1;
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto out;
while (ino <= sbi->s_ninodes) {
if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0) {
*sv_sb_fic_inode(sb,i++) = cpu_to_fs16(SYSV_SB(sb), ino);
if (i == sbi->s_fic_size)
break;
}
if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
brelse(bh);
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto out;
} else
raw_inode++;
}
brelse(bh);
out:
return i;
}
void sysv_free_inode(struct inode * inode)
{
struct super_block *sb = inode->i_sb;
struct sysv_sb_info *sbi = SYSV_SB(sb);
unsigned int ino;
struct buffer_head * bh;
struct sysv_inode * raw_inode;
unsigned count;
sb = inode->i_sb;
ino = inode->i_ino;
if (ino <= SYSV_ROOT_INO || ino > sbi->s_ninodes) {
printk("sysv_free_inode: inode 0,1,2 or nonexistent inode\n");
return;
}
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode) {
printk("sysv_free_inode: unable to read inode block on device "
"%s\n", inode->i_sb->s_id);
return;
}
mutex_lock(&sbi->s_lock);
count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
if (count < sbi->s_fic_size) {
*sv_sb_fic_inode(sb,count++) = cpu_to_fs16(sbi, ino);
*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
}
fs16_add(sbi, sbi->s_sb_total_free_inodes, 1);
dirty_sb(sb);
memset(raw_inode, 0, sizeof(struct sysv_inode));
mark_buffer_dirty(bh);
mutex_unlock(&sbi->s_lock);
brelse(bh);
}
struct inode * sysv_new_inode(const struct inode * dir, umode_t mode)
{
struct super_block *sb = dir->i_sb;
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct inode *inode;
sysv_ino_t ino;
unsigned count;
struct writeback_control wbc = {
.sync_mode = WB_SYNC_NONE
};
inode = new_inode(sb);
if (!inode)
return ERR_PTR(-ENOMEM);
mutex_lock(&sbi->s_lock);
count = fs16_to_cpu(sbi, *sbi->s_sb_fic_count);
if (count == 0 || (*sv_sb_fic_inode(sb,count-1) == 0)) {
count = refill_free_cache(sb);
if (count == 0) {
iput(inode);
mutex_unlock(&sbi->s_lock);
return ERR_PTR(-ENOSPC);
}
}
/* Now count > 0. */
ino = *sv_sb_fic_inode(sb,--count);
*sbi->s_sb_fic_count = cpu_to_fs16(sbi, count);
fs16_add(sbi, sbi->s_sb_total_free_inodes, -1);
dirty_sb(sb);
inode_init_owner(inode, dir, mode);
inode->i_ino = fs16_to_cpu(sbi, ino);
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
inode->i_blocks = 0;
memset(SYSV_I(inode)->i_data, 0, sizeof(SYSV_I(inode)->i_data));
SYSV_I(inode)->i_dir_start_lookup = 0;
insert_inode_hash(inode);
mark_inode_dirty(inode);
sysv_write_inode(inode, &wbc); /* ensure inode not allocated again */
mark_inode_dirty(inode); /* cleared by sysv_write_inode() */
/* That's it. */
mutex_unlock(&sbi->s_lock);
return inode;
}
unsigned long sysv_count_free_inodes(struct super_block * sb)
{
struct sysv_sb_info *sbi = SYSV_SB(sb);
struct buffer_head * bh;
struct sysv_inode * raw_inode;
int ino, count, sb_count;
mutex_lock(&sbi->s_lock);
sb_count = fs16_to_cpu(sbi, *sbi->s_sb_total_free_inodes);
if (0)
goto trust_sb;
/* this causes a lot of disk traffic ... */
count = 0;
ino = SYSV_ROOT_INO+1;
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto Eio;
while (ino <= sbi->s_ninodes) {
if (raw_inode->i_mode == 0 && raw_inode->i_nlink == 0)
count++;
if ((ino++ & sbi->s_inodes_per_block_1) == 0) {
brelse(bh);
raw_inode = sysv_raw_inode(sb, ino, &bh);
if (!raw_inode)
goto Eio;
} else
raw_inode++;
}
brelse(bh);
if (count != sb_count)
goto Einval;
out:
mutex_unlock(&sbi->s_lock);
return count;
Einval:
printk("sysv_count_free_inodes: "
"free inode count was %d, correcting to %d\n",
sb_count, count);
if (!(sb->s_flags & MS_RDONLY)) {
*sbi->s_sb_total_free_inodes = cpu_to_fs16(SYSV_SB(sb), count);
dirty_sb(sb);
}
goto out;
Eio:
printk("sysv_count_free_inodes: unable to read inode table\n");
trust_sb:
count = sb_count;
goto out;
}