inode.c

Linux Kernel 2.6.9 for OMAP1710

			printk(KERN_ERR "FAT: unable to set blocksize %u\n",
			       logical_sector_size);
			goto out_fail;
		}
		bh = sb_bread(sb, 0);
		if (bh == NULL) {
			printk(KERN_ERR "FAT: unable to read boot sector"
			       " (logical sector size = %lu)\n",
			       sb->s_blocksize);
			goto out_fail;
		}
		b = (struct fat_boot_sector *) bh->b_data;
	}

	sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
	sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
	sbi->fats = b->fats;
	sbi->fat_bits = 0;		/* Don't know yet */
	sbi->fat_start = CF_LE_W(b->reserved);
	sbi->fat_length = CF_LE_W(b->fat_length);
	sbi->root_cluster = 0;
	sbi->free_clusters = -1;	/* Don't know yet */
	sbi->prev_free = -1;

	if (!sbi->fat_length && b->fat32_length) {
		struct fat_boot_fsinfo *fsinfo;
		struct buffer_head *fsinfo_bh;

		/* Must be FAT32 */
		sbi->fat_bits = 32;
		sbi->fat_length = CF_LE_L(b->fat32_length);
		sbi->root_cluster = CF_LE_L(b->root_cluster);

		sb->s_maxbytes = 0xffffffff;
		
		/* MC - if info_sector is 0, don't multiply by 0 */
		sbi->fsinfo_sector = CF_LE_W(b->info_sector);
		if (sbi->fsinfo_sector == 0)
			sbi->fsinfo_sector = 1;

		fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
		if (fsinfo_bh == NULL) {
			printk(KERN_ERR "FAT: bread failed, FSINFO block"
			       " (sector = %lu)\n", sbi->fsinfo_sector);
			brelse(bh);
			goto out_fail;
		}

		fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
		if (!IS_FSINFO(fsinfo)) {
			printk(KERN_WARNING
			       "FAT: Did not find valid FSINFO signature.\n"
			       "     Found signature1 0x%08x signature2 0x%08x"
			       " (sector = %lu)\n",
			       CF_LE_L(fsinfo->signature1),
			       CF_LE_L(fsinfo->signature2),
			       sbi->fsinfo_sector);
		} else {
			sbi->free_clusters = CF_LE_L(fsinfo->free_clusters);
			sbi->prev_free = CF_LE_L(fsinfo->next_cluster);
		}

		brelse(fsinfo_bh);
	}

	sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
	sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;

	sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
	sbi->dir_entries = CF_LE_W(get_unaligned((__le16 *)&b->dir_entries));
	if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
		if (!silent)
			printk(KERN_ERR "FAT: bogus directroy-entries per block"
			       " (%u)\n", sbi->dir_entries);
		brelse(bh);
		goto out_invalid;
	}

	rootdir_sectors = sbi->dir_entries
		* sizeof(struct msdos_dir_entry) / sb->s_blocksize;
	sbi->data_start = sbi->dir_start + rootdir_sectors;
	total_sectors = CF_LE_W(get_unaligned((__le16 *)&b->sectors));
	if (total_sectors == 0)
		total_sectors = CF_LE_L(b->total_sect);

	total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;

	if (sbi->fat_bits != 32)
		sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;

	/* check that FAT table does not overflow */
	fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
	total_clusters = min(total_clusters, fat_clusters - 2);
	if (total_clusters > MAX_FAT(sb)) {
		if (!silent)
			printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
			       total_clusters);
		brelse(bh);
		goto out_invalid;
	}

	sbi->clusters = total_clusters;

	brelse(bh);

	/* validity check of FAT */
	first = __fat_access(sb, 0, -1);
	if (first < 0) {
		error = first;
		goto out_fail;
	}
	if (FAT_FIRST_ENT(sb, media) == first) {
		/* all is as it should be */
	} else if (media == 0xf8 && FAT_FIRST_ENT(sb, 0xfe) == first) {
		/* bad, reported on pc9800 */
	} else if (media == 0xf0 && FAT_FIRST_ENT(sb, 0xf8) == first) {
		/* bad, reported with a MO disk on win95/me */
	} else if (first == 0) {
		/* bad, reported with a SmartMedia card */
	} else {
		if (!silent)
			printk(KERN_ERR "FAT: invalid first entry of FAT "
			       "(0x%x != 0x%x)\n",
			       FAT_FIRST_ENT(sb, media), first);
		goto out_invalid;
	}

	error = -EINVAL;
	sprintf(buf, "cp%d", sbi->options.codepage);
	sbi->nls_disk = load_nls(buf);
	if (!sbi->nls_disk) {
		printk(KERN_ERR "FAT: codepage %s not found\n", buf);
		goto out_fail;
	}

	/* FIXME: utf8 is using iocharset for upper/lower conversion */
	if (sbi->options.isvfat) {
		sbi->nls_io = load_nls(sbi->options.iocharset);
		if (!sbi->nls_io) {
			printk(KERN_ERR "FAT: IO charset %s not found\n",
			       sbi->options.iocharset);
			goto out_fail;
		}
	}

	error = -ENOMEM;
	root_inode = new_inode(sb);
	if (!root_inode)
		goto out_fail;
	root_inode->i_ino = MSDOS_ROOT_INO;
	root_inode->i_version = 1;
	error = fat_read_root(root_inode);
	if (error < 0)
		goto out_fail;
	error = -ENOMEM;
	insert_inode_hash(root_inode);
	sb->s_root = d_alloc_root(root_inode);
	if (!sb->s_root) {
		printk(KERN_ERR "FAT: get root inode failed\n");
		goto out_fail;
	}

	return 0;

out_invalid:
	error = -EINVAL;
	if (!silent)
		printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
		       " on dev %s.\n", sb->s_id);

out_fail:
	if (root_inode)
		iput(root_inode);
	if (sbi->nls_io)
		unload_nls(sbi->nls_io);
	if (sbi->nls_disk)
		unload_nls(sbi->nls_disk);
	if (sbi->options.iocharset != fat_default_iocharset)
		kfree(sbi->options.iocharset);
	sb->s_fs_info = NULL;
	kfree(sbi);
	return error;
}

int fat_statfs(struct super_block *sb, struct kstatfs *buf)
{
	int free, nr, ret;
       
	if (MSDOS_SB(sb)->free_clusters != -1)
		free = MSDOS_SB(sb)->free_clusters;
	else {
		lock_fat(sb);
		if (MSDOS_SB(sb)->free_clusters != -1)
			free = MSDOS_SB(sb)->free_clusters;
		else {
			free = 0;
			for (nr = 2; nr < MSDOS_SB(sb)->clusters + 2; nr++) {
				ret = fat_access(sb, nr, -1);
				if (ret < 0) {
					unlock_fat(sb);
					return ret;
				} else if (ret == FAT_ENT_FREE)
					free++;
			}
			MSDOS_SB(sb)->free_clusters = free;
		}
		unlock_fat(sb);
	}

	buf->f_type = sb->s_magic;
	buf->f_bsize = MSDOS_SB(sb)->cluster_size;
	buf->f_blocks = MSDOS_SB(sb)->clusters;
	buf->f_bfree = free;
	buf->f_bavail = free;
	buf->f_namelen = MSDOS_SB(sb)->options.isvfat ? 260 : 12;

	return 0;
}

static int is_exec(unsigned char *extension)
{
	unsigned char *exe_extensions = "EXECOMBAT", *walk;

	for (walk = exe_extensions; *walk; walk += 3)
		if (!strncmp(extension, walk, 3))
			return 1;
	return 0;
}

static int fat_writepage(struct page *page, struct writeback_control *wbc)
{
	return block_write_full_page(page,fat_get_block, wbc);
}
static int fat_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page,fat_get_block);
}

static int
fat_prepare_write(struct file *file, struct page *page,
			unsigned from, unsigned to)
{
	kmap(page);
	return cont_prepare_write(page,from,to,fat_get_block,
		&MSDOS_I(page->mapping->host)->mmu_private);
}

static int
fat_commit_write(struct file *file, struct page *page,
			unsigned from, unsigned to)
{
	kunmap(page);
	return generic_commit_write(file, page, from, to);
}

static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
{
	return generic_block_bmap(mapping,block,fat_get_block);
}
static struct address_space_operations fat_aops = {
	.readpage = fat_readpage,
	.writepage = fat_writepage,
	.sync_page = block_sync_page,
	.prepare_write = fat_prepare_write,
	.commit_write = fat_commit_write,
	.bmap = _fat_bmap
};

/* doesn't deal with root inode */
static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
{
	struct super_block *sb = inode->i_sb;
	struct msdos_sb_info *sbi = MSDOS_SB(sb);
	int error;

	MSDOS_I(inode)->file_cluster = MSDOS_I(inode)->disk_cluster = 0;
	MSDOS_I(inode)->i_pos = 0;
	inode->i_uid = sbi->options.fs_uid;
	inode->i_gid = sbi->options.fs_gid;
	inode->i_version++;
	inode->i_generation = get_seconds();
	
	if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
		inode->i_generation &= ~1;
		inode->i_mode = MSDOS_MKMODE(de->attr,
			S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
		inode->i_op = sbi->dir_ops;
		inode->i_fop = &fat_dir_operations;

		MSDOS_I(inode)->i_start = CF_LE_W(de->start);
		if (sbi->fat_bits == 32)
			MSDOS_I(inode)->i_start |= (CF_LE_W(de->starthi) << 16);

		MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
		error = fat_calc_dir_size(inode);
		if (error < 0)
			return error;
		MSDOS_I(inode)->mmu_private = inode->i_size;

		inode->i_nlink = fat_subdirs(inode);
	} else { /* not a directory */
		inode->i_generation |= 1;
		inode->i_mode = MSDOS_MKMODE(de->attr,
		    ((sbi->options.showexec &&
		       !is_exec(de->ext))
		    	? S_IRUGO|S_IWUGO : S_IRWXUGO)
		    & ~sbi->options.fs_fmask) | S_IFREG;
		MSDOS_I(inode)->i_start = CF_LE_W(de->start);
		if (sbi->fat_bits == 32)
			MSDOS_I(inode)->i_start |= (CF_LE_W(de->starthi) << 16);

		MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
		inode->i_size = CF_LE_L(de->size);
	        inode->i_op = &fat_file_inode_operations;
	        inode->i_fop = &fat_file_operations;
		inode->i_mapping->a_ops = &fat_aops;
		MSDOS_I(inode)->mmu_private = inode->i_size;
	}
	if(de->attr & ATTR_SYS)
		if (sbi->options.sys_immutable)
			inode->i_flags |= S_IMMUTABLE;
	MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED;
	/* this is as close to the truth as we can get ... */
	inode->i_blksize = sbi->cluster_size;
	inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
			   & ~((loff_t)sbi->cluster_size - 1)) >> 9;
	inode->i_mtime.tv_sec = inode->i_atime.tv_sec =
		date_dos2unix(CF_LE_W(de->time),CF_LE_W(de->date));
	inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = 0;
	inode->i_ctime.tv_sec =
		MSDOS_SB(sb)->options.isvfat
		? date_dos2unix(CF_LE_W(de->ctime),CF_LE_W(de->cdate))
		: inode->i_mtime.tv_sec;
	inode->i_ctime.tv_nsec = de->ctime_ms * 1000000;
	MSDOS_I(inode)->i_ctime_ms = de->ctime_ms;

	return 0;
}

int fat_write_inode(struct inode *inode, int wait)
{
	struct super_block *sb = inode->i_sb;
	struct buffer_head *bh;
	struct msdos_dir_entry *raw_entry;
	loff_t i_pos;

retry:
	i_pos = MSDOS_I(inode)->i_pos;
	if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) {
		return 0;
	}
	lock_kernel();
	if (!(bh = sb_bread(sb, i_pos >> MSDOS_SB(sb)->dir_per_block_bits))) {
		printk(KERN_ERR "FAT: unable to read inode block "
		       "for updating (i_pos %lld)\n", i_pos);
		unlock_kernel();
		return -EIO;
	}
	spin_lock(&fat_inode_lock);
	if (i_pos != MSDOS_I(inode)->i_pos) {
		spin_unlock(&fat_inode_lock);
		brelse(bh);
		unlock_kernel();
		goto retry;
	}

	raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
	    [i_pos & (MSDOS_SB(sb)->dir_per_block - 1)];
	if (S_ISDIR(inode->i_mode)) {
		raw_entry->attr = ATTR_DIR;
		raw_entry->size = 0;
	}
	else {
		raw_entry->attr = ATTR_NONE;
		raw_entry->size = CT_LE_L(inode->i_size);
	}
	raw_entry->attr |= MSDOS_MKATTR(inode->i_mode) |
	    MSDOS_I(inode)->i_attrs;
	raw_entry->start = CT_LE_W(MSDOS_I(inode)->i_logstart);
	raw_entry->starthi = CT_LE_W(MSDOS_I(inode)->i_logstart >> 16);
	fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
	if (MSDOS_SB(sb)->options.isvfat) {
		fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
		raw_entry->ctime_ms = MSDOS_I(inode)->i_ctime_ms; /* use i_ctime.tv_nsec? */
	}
	spin_unlock(&fat_inode_lock);
	mark_buffer_dirty(bh);
	brelse(bh);
	unlock_kernel();
	return 0;
}


int fat_notify_change(struct dentry * dentry, struct iattr * attr)
{
	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
	struct inode *inode = dentry->d_inode;
	int mask, error = 0;

	lock_kernel();

	/* FAT cannot truncate to a longer file */
	if (attr->ia_valid & ATTR_SIZE) {
		if (attr->ia_size > inode->i_size) {
			error = -EPERM;
			goto out;
		}
	}

	error = inode_change_ok(inode, attr);
	if (error) {
		if (sbi->options.quiet)
			error = 0;
 		goto out;
	}

	if (((attr->ia_valid & ATTR_UID) && 
	     (attr->ia_uid != sbi->options.fs_uid)) ||
	    ((attr->ia_valid & ATTR_GID) && 
	     (attr->ia_gid != sbi->options.fs_gid)) ||
	    ((attr->ia_valid & ATTR_MODE) &&
	     (attr->ia_mode & ~MSDOS_VALID_MODE)))
		error = -EPERM;

	if (error) {
		if (sbi->options.quiet)  
			error = 0;
		goto out;
	}
	error = inode_setattr(inode, attr);
	if (error)
		goto out;

	if (S_ISDIR(inode->i_mode))
		mask = sbi->options.fs_dmask;
	else
		mask = sbi->options.fs_fmask;
	inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask);
out:
	unlock_kernel();
	return error;
}
MODULE_LICENSE("GPL");