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/*
* linux/fs/adfs/inode.c
*
* Copyright (C) 1997-1999 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/adfs_fs.h>
#include <linux/time.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/module.h>
#include <linux/buffer_head.h>
#include "adfs.h"
/*
* Lookup/Create a block at offset 'block' into 'inode'. We currently do
* not support creation of new blocks, so we return -EIO for this case.
*/
static int
adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh,
int create)
{
if (block < 0)
goto abort_negative;
if (!create) {
if (block >= inode->i_blocks)
goto abort_toobig;
block = __adfs_block_map(inode->i_sb, inode->i_ino, block);
if (block)
map_bh(bh, inode->i_sb, block);
return 0;
}
/* don't support allocation of blocks yet */
return -EIO;
abort_negative:
adfs_error(inode->i_sb, "block %d < 0", block);
return -EIO;
abort_toobig:
return 0;
}
static int adfs_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, adfs_get_block, wbc);
}
static int adfs_readpage(struct file *file, struct page *page)
{
return block_read_full_page(page, adfs_get_block);
}
static int adfs_prepare_write(struct file *file, struct page *page, unsigned int from, unsigned int to)
{
return cont_prepare_write(page, from, to, adfs_get_block,
&ADFS_I(page->mapping->host)->mmu_private);
}
static sector_t _adfs_bmap(struct address_space *mapping, sector_t block)
{
return generic_block_bmap(mapping, block, adfs_get_block);
}
static struct address_space_operations adfs_aops = {
.readpage = adfs_readpage,
.writepage = adfs_writepage,
.sync_page = block_sync_page,
.prepare_write = adfs_prepare_write,
.commit_write = generic_commit_write,
.bmap = _adfs_bmap
};
static inline unsigned int
adfs_filetype(struct inode *inode)
{
unsigned int type;
if (ADFS_I(inode)->stamped)
type = (ADFS_I(inode)->loadaddr >> 8) & 0xfff;
else
type = (unsigned int) -1;
return type;
}
/*
* Convert ADFS attributes and filetype to Linux permission.
*/
static umode_t
adfs_atts2mode(struct super_block *sb, struct inode *inode)
{
unsigned int filetype, attr = ADFS_I(inode)->attr;
umode_t mode, rmask;
struct adfs_sb_info *asb = ADFS_SB(sb);
if (attr & ADFS_NDA_DIRECTORY) {
mode = S_IRUGO & asb->s_owner_mask;
return S_IFDIR | S_IXUGO | mode;
}
filetype = adfs_filetype(inode);
switch (filetype) {
case 0xfc0: /* LinkFS */
return S_IFLNK|S_IRWXUGO;
case 0xfe6: /* UnixExec */
rmask = S_IRUGO | S_IXUGO;
break;
default:
rmask = S_IRUGO;
}
mode = S_IFREG;
if (attr & ADFS_NDA_OWNER_READ)
mode |= rmask & asb->s_owner_mask;
if (attr & ADFS_NDA_OWNER_WRITE)
mode |= S_IWUGO & asb->s_owner_mask;
if (attr & ADFS_NDA_PUBLIC_READ)
mode |= rmask & asb->s_other_mask;
if (attr & ADFS_NDA_PUBLIC_WRITE)
mode |= S_IWUGO & asb->s_other_mask;
return mode;
}
/*
* Convert Linux permission to ADFS attribute. We try to do the reverse
* of atts2mode, but there is not a 1:1 translation.
*/
static int
adfs_mode2atts(struct super_block *sb, struct inode *inode)
{
umode_t mode;
int attr;
struct adfs_sb_info *asb = ADFS_SB(sb);
/* FIXME: should we be able to alter a link? */
if (S_ISLNK(inode->i_mode))
return ADFS_I(inode)->attr;
if (S_ISDIR(inode->i_mode))
attr = ADFS_NDA_DIRECTORY;
else
attr = 0;
mode = inode->i_mode & asb->s_owner_mask;
if (mode & S_IRUGO)
attr |= ADFS_NDA_OWNER_READ;
if (mode & S_IWUGO)
attr |= ADFS_NDA_OWNER_WRITE;
mode = inode->i_mode & asb->s_other_mask;
mode &= ~asb->s_owner_mask;
if (mode & S_IRUGO)
attr |= ADFS_NDA_PUBLIC_READ;
if (mode & S_IWUGO)
attr |= ADFS_NDA_PUBLIC_WRITE;
return attr;
}
/*
* Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time
* referenced to 1 Jan 1900 (til 2248)
*/
static void
adfs_adfs2unix_time(struct timespec *tv, struct inode *inode)
{
unsigned int high, low;
if (ADFS_I(inode)->stamped == 0)
goto cur_time;
high = ADFS_I(inode)->loadaddr << 24;
low = ADFS_I(inode)->execaddr;
high |= low >> 8;
low &= 255;
/* Files dated pre 01 Jan 1970 00:00:00. */
if (high < 0x336e996a)
goto too_early;
/* Files dated post 18 Jan 2038 03:14:05. */
if (high >= 0x656e9969)
goto too_late;
/* discard 2208988800 (0x336e996a00) seconds of time */
high -= 0x336e996a;
/* convert 40-bit centi-seconds to 32-bit seconds */
tv->tv_sec = (((high % 100) << 8) + low) / 100 + (high / 100 << 8);
tv->tv_nsec = 0;
return;
cur_time:
*tv = CURRENT_TIME_SEC;
return;
too_early:
tv->tv_sec = tv->tv_nsec = 0;
return;
too_late:
tv->tv_sec = 0x7ffffffd;
tv->tv_nsec = 0;
return;
}
/*
* Convert an Unix time to ADFS time. We only do this if the entry has a
* time/date stamp already.
*/
static void
adfs_unix2adfs_time(struct inode *inode, unsigned int secs)
{
unsigned int high, low;
if (ADFS_I(inode)->stamped) {
/* convert 32-bit seconds to 40-bit centi-seconds */
low = (secs & 255) * 100;
high = (secs / 256) * 100 + (low >> 8) + 0x336e996a;
ADFS_I(inode)->loadaddr = (high >> 24) |
(ADFS_I(inode)->loadaddr & ~0xff);
ADFS_I(inode)->execaddr = (low & 255) | (high << 8);
}
}
/*
* Fill in the inode information from the object information.
*
* Note that this is an inode-less filesystem, so we can't use the inode
* number to reference the metadata on the media. Instead, we use the
* inode number to hold the object ID, which in turn will tell us where
* the data is held. We also save the parent object ID, and with these
* two, we can locate the metadata.
*
* This does mean that we rely on an objects parent remaining the same at
* all times - we cannot cope with a cross-directory rename (yet).
*/
struct inode *
adfs_iget(struct super_block *sb, struct object_info *obj)
{
struct inode *inode;
inode = new_inode(sb);
if (!inode)
goto out;
inode->i_uid = ADFS_SB(sb)->s_uid;
inode->i_gid = ADFS_SB(sb)->s_gid;
inode->i_ino = obj->file_id;
inode->i_size = obj->size;
inode->i_nlink = 2;
inode->i_blksize = PAGE_SIZE;
inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
/*
* we need to save the parent directory ID so that
* write_inode can update the directory information
* for this file. This will need special handling
* for cross-directory renames.
*/
ADFS_I(inode)->parent_id
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