inode.c

嵌入式系统设计与实验教材二源码linux内核移植与编译

					goto abort;
				ninode = iget(inode->i_sb, nextino);
				if (!ninode)
					goto abort;
				firstext  = ninode->u.isofs_i.i_first_extent;
				sect_size = ninode->u.isofs_i.i_section_size;
				nextino   = ninode->u.isofs_i.i_next_section_ino;
				iput(ninode);
				
				if (++section > 100) {
					printk("isofs_get_blocks: More than 100 file sections ?!?, aborting...\n");
					printk("isofs_get_blocks: ino=%lu block=%ld firstext=%u sect_size=%u nextino=%lu\n",
					       inode->i_ino, iblock, firstext, (unsigned) sect_size, nextino);
					goto abort;
				}
			}
		}
		
		if ( *bh_result ) {
			(*bh_result)->b_dev      = inode->i_dev;
			(*bh_result)->b_blocknr  = firstext + b_off - offset;
			(*bh_result)->b_state   |= (1UL << BH_Mapped);
		} else {
			*bh_result = sb_getblk(inode->i_sb, firstext+b_off-offset);
			if ( !*bh_result )
				goto abort;
		}
		bh_result++;	/* Next buffer head */
		b_off++;	/* Next buffer offset */
		nblocks--;
		rv++;
	}


abort:
	unlock_kernel();
	return rv;
}

/*
 * Used by the standard interfaces.
 */
static int isofs_get_block(struct inode *inode, long iblock,
		    struct buffer_head *bh_result, int create)
{
	if ( create ) {
		printk("isofs_get_block: Kernel tries to allocate a block\n");
		return -EROFS;
	}

	return isofs_get_blocks(inode, iblock, &bh_result, 1) ? 0 : -EIO;
}

static int isofs_bmap(struct inode *inode, int block)
{
	struct buffer_head dummy;
	int error;

	dummy.b_state = 0;
	dummy.b_blocknr = -1000;
	error = isofs_get_block(inode, block, &dummy, 0);
	if (!error)
		return dummy.b_blocknr;
	return 0;
}

struct buffer_head *isofs_bread(struct inode *inode, unsigned int block)
{
	unsigned int blknr = isofs_bmap(inode, block);
	if (!blknr)
		return NULL;
	return sb_bread(inode->i_sb, blknr);
}

static int isofs_readpage(struct file *file, struct page *page)
{
	return block_read_full_page(page,isofs_get_block);
}

static int _isofs_bmap(struct address_space *mapping, long block)
{
	return generic_block_bmap(mapping,block,isofs_get_block);
}

static struct address_space_operations isofs_aops = {
	readpage: isofs_readpage,
	sync_page: block_sync_page,
	bmap: _isofs_bmap
};

static inline void test_and_set_uid(uid_t *p, uid_t value)
{
	if(value) {
		*p = value;
	}
}

static inline void test_and_set_gid(gid_t *p, gid_t value)
{
        if(value) {
                *p = value;
        }
}

static int isofs_read_level3_size(struct inode * inode)
{
	unsigned long f_pos = inode->i_ino;
	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	int high_sierra = inode->i_sb->u.isofs_sb.s_high_sierra;
	struct buffer_head * bh = NULL;
	unsigned long block, offset;
	int i = 0;
	int more_entries = 0;
	struct iso_directory_record * tmpde = NULL;

	inode->i_size = 0;
	inode->u.isofs_i.i_next_section_ino = 0;

	block = f_pos >> ISOFS_BUFFER_BITS(inode);
	offset = f_pos & (bufsize-1);

	do {
		struct iso_directory_record * de;
		unsigned int de_len;

		if (!bh) {
			bh = sb_bread(inode->i_sb, block);
			if (!bh)
				goto out_noread;
		}
		de = (struct iso_directory_record *) (bh->b_data + offset);
		de_len = *(unsigned char *) de;

		if (de_len == 0) {
			brelse(bh);
			bh = NULL;
			f_pos = (f_pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
			block = f_pos >> ISOFS_BUFFER_BITS(inode);
			offset = 0;
			continue;
		}

		offset += de_len;

		/* Make sure we have a full directory entry */
		if (offset >= bufsize) {
			int slop = bufsize - offset + de_len;
			if (!tmpde) {
				tmpde = kmalloc(256, GFP_KERNEL);
				if (!tmpde)
					goto out_nomem;
			}
			memcpy(tmpde, de, slop);
			offset &= bufsize - 1;
			block++;
			brelse(bh);
			bh = NULL;
			if (offset) {
				bh = sb_bread(inode->i_sb, block);
				if (!bh)
					goto out_noread;
				memcpy((void *) tmpde + slop, bh->b_data, offset);
			}
			de = tmpde;
		}

		inode->i_size += isonum_733(de->size);
		if (i == 1)
			inode->u.isofs_i.i_next_section_ino = f_pos;

		more_entries = de->flags[-high_sierra] & 0x80;

		f_pos += de_len;
		i++;
		if(i > 100)
			goto out_toomany;
	} while(more_entries);
out:
	if (tmpde)
		kfree(tmpde);
	if (bh)
		brelse(bh);
	return 0;

out_nomem:
	if (bh)
		brelse(bh);
	return -ENOMEM;

out_noread:
	printk(KERN_INFO "ISOFS: unable to read i-node block %lu\n", block);
	if (tmpde)
		kfree(tmpde);
	return -EIO;

out_toomany:
	printk(KERN_INFO "isofs_read_level3_size: "
		"More than 100 file sections ?!?, aborting...\n"
	  	"isofs_read_level3_size: inode=%lu ino=%lu\n",
		inode->i_ino, f_pos);
	goto out;
}

static void isofs_read_inode(struct inode * inode)
{
	struct super_block *sb = inode->i_sb;
	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	int block = inode->i_ino >> ISOFS_BUFFER_BITS(inode);
	int high_sierra = sb->u.isofs_sb.s_high_sierra;
	struct buffer_head * bh = NULL;
	struct iso_directory_record * de;
	struct iso_directory_record * tmpde = NULL;
	unsigned int de_len;
	unsigned long offset;
	int volume_seq_no, i;

	bh = sb_bread(inode->i_sb, block);
	if (!bh)
		goto out_badread;

	offset = (inode->i_ino & (bufsize - 1));
	de = (struct iso_directory_record *) (bh->b_data + offset);
	de_len = *(unsigned char *) de;

	if (offset + de_len > bufsize) {
		int frag1 = bufsize - offset;

		tmpde = kmalloc(de_len, GFP_KERNEL);
		if (tmpde == NULL) {
			printk(KERN_INFO "isofs_read_inode: out of memory\n");
			goto fail;
		}
		memcpy(tmpde, bh->b_data + offset, frag1);
		brelse(bh);
		bh = sb_bread(inode->i_sb, ++block);
		if (!bh)
			goto out_badread;
		memcpy((char *)tmpde+frag1, bh->b_data, de_len - frag1);
		de = tmpde;
	}

	/* Assume it is a normal-format file unless told otherwise */
	inode->u.isofs_i.i_file_format = isofs_file_normal;

	if (de->flags[-high_sierra] & 2) {
		inode->i_mode = S_IRUGO | S_IXUGO | S_IFDIR;
		inode->i_nlink = 1; /* Set to 1.  We know there are 2, but
				       the find utility tries to optimize
				       if it is 2, and it screws up.  It is
				       easier to give 1 which tells find to
				       do it the hard way. */
	} else {
 		/* Everybody gets to read the file. */
		inode->i_mode = inode->i_sb->u.isofs_sb.s_mode;
		inode->i_nlink = 1;
	        inode->i_mode |= S_IFREG;
		/* If there are no periods in the name,
		 * then set the execute permission bit
		 */
		for(i=0; i< de->name_len[0]; i++)
			if(de->name[i]=='.' || de->name[i]==';')
				break;
		if(i == de->name_len[0] || de->name[i] == ';')
			inode->i_mode |= S_IXUGO; /* execute permission */
	}
	inode->i_uid = inode->i_sb->u.isofs_sb.s_uid;
	inode->i_gid = inode->i_sb->u.isofs_sb.s_gid;
	inode->i_blocks = inode->i_blksize = 0;


	inode->u.isofs_i.i_section_size = isonum_733 (de->size);
	if(de->flags[-high_sierra] & 0x80) {
		if(isofs_read_level3_size(inode)) goto fail;
	} else {
		inode->i_size = isonum_733 (de->size);
	}

	/*
	 * The ISO-9660 filesystem only stores 32 bits for file size.
	 * mkisofs handles files up to 2GB-2 = 2147483646 = 0x7FFFFFFE bytes
	 * in size. This is according to the large file summit paper from 1996.
	 * WARNING: ISO-9660 filesystems > 1 GB and even > 2 GB are fully
	 *	    legal. Do not prevent to use DVD's [e-mail]
	 */
	if ((inode->i_size < 0 || inode->i_size > 0x7FFFFFFE) &&
	    inode->i_sb->u.isofs_sb.s_cruft == 'n') {
		printk(KERN_WARNING "Warning: defective CD-ROM.  "
		       "Enabling \"cruft\" mount option.\n");
		inode->i_sb->u.isofs_sb.s_cruft = 'y';
	}

	/*
	 * Some dipshit decided to store some other bit of information
	 * in the high byte of the file length.  Catch this and holler.
	 * WARNING: this will make it impossible for a file to be > 16MB
	 * on the CDROM.
	 */

	if (inode->i_sb->u.isofs_sb.s_cruft == 'y' &&
	    inode->i_size & 0xff000000) {
		inode->i_size &= 0x00ffffff;
	}

	if (de->interleave[0]) {
		printk("Interleaved files not (yet) supported.\n");
		inode->i_size = 0;
	}

	/* I have no idea what file_unit_size is used for, so
	   we will flag it for now */
	if (de->file_unit_size[0] != 0) {
		printk("File unit size != 0 for ISO file (%ld).\n",
		       inode->i_ino);
	}

	/* I have no idea what other flag bits are used for, so
	   we will flag it for now */
#ifdef DEBUG
	if((de->flags[-high_sierra] & ~2)!= 0){
		printk("Unusual flag settings for ISO file (%ld %x).\n",
		       inode->i_ino, de->flags[-high_sierra]);
	}
#endif

	inode->i_mtime = inode->i_atime = inode->i_ctime =
		iso_date(de->date, high_sierra);

	inode->u.isofs_i.i_first_extent = (isonum_733 (de->extent) +
					   isonum_711 (de->ext_attr_length));

	/* Set the number of blocks for stat() - should be done before RR */
	inode->i_blksize = PAGE_CACHE_SIZE; /* For stat() only */
	inode->i_blocks  = (inode->i_size + 511) >> 9;

	/*
	 * Now test for possible Rock Ridge extensions which will override
	 * some of these numbers in the inode structure.
	 */

	if (!high_sierra) {
		parse_rock_ridge_inode(de, inode);
		/* if we want uid/gid set, override the rock ridge setting */
		test_and_set_uid(&inode->i_uid, inode->i_sb->u.isofs_sb.s_uid);
		test_and_set_gid(&inode->i_gid, inode->i_sb->u.isofs_sb.s_gid);
	}

	/* get the volume sequence number */
	volume_seq_no = isonum_723 (de->volume_sequence_number) ;

	/*
	 * Disable checking if we see any volume number other than 0 or 1.
	 * We could use the cruft option, but that has multiple purposes, one
	 * of which is limiting the file size to 16Mb.  Thus we silently allow
	 * volume numbers of 0 to go through without complaining.
	 */
	if (inode->i_sb->u.isofs_sb.s_cruft == 'n' &&
	    (volume_seq_no != 0) && (volume_seq_no != 1)) {
		printk(KERN_WARNING "Warning: defective CD-ROM "
		       "(volume sequence number %d). "
		       "Enabling \"cruft\" mount option.\n", volume_seq_no);
		inode->i_sb->u.isofs_sb.s_cruft = 'y';
	}

	/* Install the inode operations vector */
#ifndef IGNORE_WRONG_MULTI_VOLUME_SPECS
	if (inode->i_sb->u.isofs_sb.s_cruft != 'y' &&
	    (volume_seq_no != 0) && (volume_seq_no != 1)) {
		printk(KERN_WARNING "Multi-volume CD somehow got mounted.\n");
	} else
#endif /*IGNORE_WRONG_MULTI_VOLUME_SPECS */
	{
		if (S_ISREG(inode->i_mode)) {
			inode->i_fop = &generic_ro_fops;
			switch ( inode->u.isofs_i.i_file_format ) {
#ifdef CONFIG_ZISOFS
			case isofs_file_compressed:
				inode->i_data.a_ops = &zisofs_aops;
				break;
#endif
			default:
				inode->i_data.a_ops = &isofs_aops;
				break;
			}
		} else if (S_ISDIR(inode->i_mode)) {
			inode->i_op = &isofs_dir_inode_operations;
			inode->i_fop = &isofs_dir_operations;
		} else if (S_ISLNK(inode->i_mode)) {
			inode->i_op = &page_symlink_inode_operations;
			inode->i_data.a_ops = &isofs_symlink_aops;
		} else
			/* XXX - parse_rock_ridge_inode() had already set i_rdev. */
			init_special_inode(inode, inode->i_mode,
					   kdev_t_to_nr(inode->i_rdev));
	}
 out:
	if (tmpde)
		kfree(tmpde);
	if (bh)
		brelse(bh);
	return;

 out_badread:
	printk(KERN_WARNING "ISOFS: unable to read i-node block\n");
 fail:
	make_bad_inode(inode);
	goto out;
}

#ifdef LEAK_CHECK
#undef malloc
#undef free_s
#undef sb_bread
#undef brelse

void * leak_check_malloc(unsigned int size){
  void * tmp;
  check_malloc++;
  tmp = kmalloc(size, GFP_KERNEL);
  return tmp;
}

void leak_check_free_s(void * obj, int size){
  check_malloc--;
  return kfree(obj);
}

struct buffer_head * leak_check_bread(struct super_block *sb, int block){
  check_bread++;
  return sb_bread(sb, block);
}

void leak_check_brelse(struct buffer_head * bh){
  check_bread--;
  return brelse(bh);
}

#endif

static DECLARE_FSTYPE_DEV(iso9660_fs_type, "iso9660", isofs_read_super);

static int __init init_iso9660_fs(void)
{
#ifdef CONFIG_ZISOFS
	int err;

	err = zisofs_init();
	if ( err )
		return err;
#endif
        return register_filesystem(&iso9660_fs_type);
}

static void __exit exit_iso9660_fs(void)
{
        unregister_filesystem(&iso9660_fs_type);
#ifdef CONFIG_ZISOFS
	zisofs_cleanup();
#endif
}

EXPORT_NO_SYMBOLS;

module_init(init_iso9660_fs)
module_exit(exit_iso9660_fs)
MODULE_LICENSE("GPL");