super.c

嵌入式系统设计与实例开发源码

/*
 * super.c
 *
 * PURPOSE
 *  Super block routines for the OSTA-UDF(tm) filesystem.
 *
 * DESCRIPTION
 *  OSTA-UDF(tm) = Optical Storage Technology Association
 *  Universal Disk Format.
 *
 *  This code is based on version 2.00 of the UDF specification,
 *  and revision 3 of the ECMA 167 standard [equivalent to ISO 13346].
 *    http://www.osta.org/
 *    http://www.ecma.ch/
 *    http://www.iso.org/
 *
 * CONTACTS
 *  E-mail regarding any portion of the Linux UDF file system should be
 *  directed to the development team mailing list (run by majordomo):
 *	  [e-mail]
 *
 * COPYRIGHT
 *  This file is distributed under the terms of the GNU General Public
 *  License (GPL). Copies of the GPL can be obtained from:
 *    ftp://prep.ai.mit.edu/pub/gnu/GPL
 *  Each contributing author retains all rights to their own work.
 *
 *  (C) 1998 Dave Boynton
 *  (C) 1998-2000 Ben Fennema
 *  (C) 2000 Stelias Computing Inc
 *
 * HISTORY
 *
 *  09/24/98 dgb  changed to allow compiling outside of kernel, and
 *                added some debugging.
 *  10/01/98 dgb  updated to allow (some) possibility of compiling w/2.0.34
 *  10/16/98      attempting some multi-session support
 *  10/17/98      added freespace count for "df"
 *  11/11/98 gr   added novrs option
 *  11/26/98 dgb  added fileset,anchor mount options
 *  12/06/98 blf  really hosed things royally. vat/sparing support. sequenced vol descs
 *                rewrote option handling based on isofs
 *  12/20/98      find the free space bitmap (if it exists)
 */

#include "udfdecl.h"    

#include <linux/config.h>
#include <linux/version.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/locks.h>
#include <linux/module.h>
#include <linux/stat.h>
#include <linux/cdrom.h>
#include <linux/nls.h>
#include <asm/byteorder.h>

#include <linux/udf_fs.h>
#include "udf_sb.h"
#include "udf_i.h"

#include <linux/init.h>
#include <asm/uaccess.h>

#define VDS_POS_PRIMARY_VOL_DESC	0
#define VDS_POS_UNALLOC_SPACE_DESC	1
#define VDS_POS_LOGICAL_VOL_DESC	2
#define VDS_POS_PARTITION_DESC		3
#define VDS_POS_IMP_USE_VOL_DESC	4
#define VDS_POS_VOL_DESC_PTR		5
#define VDS_POS_TERMINATING_DESC	6
#define VDS_POS_LENGTH			7

static char error_buf[1024];

/* These are the "meat" - everything else is stuffing */
static struct super_block *udf_read_super(struct super_block *, void *, int);
static void udf_put_super(struct super_block *);
static void udf_write_super(struct super_block *);
static int udf_remount_fs(struct super_block *, int *, char *);
static int udf_check_valid(struct super_block *, int, int);
static int udf_vrs(struct super_block *sb, int silent);
static int udf_load_partition(struct super_block *, lb_addr *);
static int udf_load_logicalvol(struct super_block *, struct buffer_head *, lb_addr *);
static void udf_load_logicalvolint(struct super_block *, extent_ad);
static void udf_find_anchor(struct super_block *);
static int udf_find_fileset(struct super_block *, lb_addr *, lb_addr *);
static void udf_load_pvoldesc(struct super_block *, struct buffer_head *);
static void udf_load_fileset(struct super_block *, struct buffer_head *, lb_addr *);
static void udf_load_partdesc(struct super_block *, struct buffer_head *);
static void udf_open_lvid(struct super_block *);
static void udf_close_lvid(struct super_block *);
static unsigned int udf_count_free(struct super_block *);
static int udf_statfs(struct super_block *, struct statfs *);

/* UDF filesystem type */
static DECLARE_FSTYPE_DEV(udf_fstype, "udf", udf_read_super);

/* Superblock operations */
static struct super_operations udf_sb_ops = {
	read_inode:		udf_read_inode,
	write_inode:		udf_write_inode,
	put_inode:		udf_put_inode,
	delete_inode:		udf_delete_inode,
	put_super:		udf_put_super,
	write_super:		udf_write_super,
	statfs:			udf_statfs,
	remount_fs:		udf_remount_fs,
};

struct udf_options
{
	unsigned char novrs;
	unsigned int blocksize;
	unsigned int session;
	unsigned int lastblock;
	unsigned int anchor;
	unsigned int volume;
	unsigned short partition;
	unsigned int fileset;
	unsigned int rootdir;
	unsigned int flags;
	mode_t umask;
	gid_t gid;
	uid_t uid;
	struct nls_table *nls_map;
};

static int __init init_udf_fs(void)
{
	printk(KERN_NOTICE "udf: registering filesystem\n");
	return register_filesystem(&udf_fstype);
}

static void __exit exit_udf_fs(void)
{
	printk(KERN_NOTICE "udf: unregistering filesystem\n");
	unregister_filesystem(&udf_fstype);
}

EXPORT_NO_SYMBOLS;

module_init(init_udf_fs)
module_exit(exit_udf_fs)

/*
 * udf_parse_options
 *
 * PURPOSE
 *	Parse mount options.
 *
 * DESCRIPTION
 *	The following mount options are supported:
 *
 *	gid=		Set the default group.
 *	umask=		Set the default umask.
 *	uid=		Set the default user.
 *	bs=			Set the block size.
 *	unhide		Show otherwise hidden files.
 *	undelete	Show deleted files in lists.
 *	adinicb		Embed data in the inode (default)
 *	noadinicb	Don't embed data in the inode
 *	shortad		Use short ad's
 *	longad		Use long ad's (default)
 *	nostrict	Unset strict conformance
 *	iocharset=	Set the NLS character set
 *
 *	The remaining are for debugging and disaster recovery:
 *
 *	novrs		Skip volume sequence recognition 
 *
 *	The following expect a offset from 0.
 *
 *	session=	Set the CDROM session (default= last session)
 *	anchor=		Override standard anchor location. (default= 256)
 *	volume=		Override the VolumeDesc location. (unused)
 *	partition=	Override the PartitionDesc location. (unused)
 *	lastblock=	Set the last block of the filesystem/
 *
 *	The following expect a offset from the partition root.
 *
 *	fileset=	Override the fileset block location. (unused)
 *	rootdir=	Override the root directory location. (unused)
 *		WARNING: overriding the rootdir to a non-directory may
 *		yield highly unpredictable results.
 *
 * PRE-CONDITIONS
 *	options		Pointer to mount options string.
 *	uopts		Pointer to mount options variable.
 *
 * POST-CONDITIONS
 *	<return>	0	Mount options parsed okay.
 *	<return>	-1	Error parsing mount options.
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 */

static int
udf_parse_options(char *options, struct udf_options *uopt)
{
	char *opt, *val;

	uopt->novrs = 0;
	uopt->blocksize = 2048;
	uopt->partition = 0xFFFF;
	uopt->session = 0xFFFFFFFF;
	uopt->lastblock = 0;
	uopt->anchor = 0;
	uopt->volume = 0xFFFFFFFF;
	uopt->rootdir = 0xFFFFFFFF;
	uopt->fileset = 0xFFFFFFFF;
	uopt->nls_map = NULL;

	if (!options)
		return 1;

	for (opt = strtok(options, ","); opt; opt = strtok(NULL, ","))
	{
		/* Make "opt=val" into two strings */
		val = strchr(opt, '=');
		if (val)
			*(val++) = 0;
		if (!strcmp(opt, "novrs") && !val)
			uopt->novrs = 1;
		else if (!strcmp(opt, "bs") && val)
			uopt->blocksize = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "unhide") && !val)
			uopt->flags |= (1 << UDF_FLAG_UNHIDE);
		else if (!strcmp(opt, "undelete") && !val)
			uopt->flags |= (1 << UDF_FLAG_UNDELETE);
		else if (!strcmp(opt, "noadinicb") && !val)
			uopt->flags &= ~(1 << UDF_FLAG_USE_AD_IN_ICB);
		else if (!strcmp(opt, "adinicb") && !val)
			uopt->flags |= (1 << UDF_FLAG_USE_AD_IN_ICB);
		else if (!strcmp(opt, "shortad") && !val)
			uopt->flags |= (1 << UDF_FLAG_USE_SHORT_AD);
		else if (!strcmp(opt, "longad") && !val)
			uopt->flags &= ~(1 << UDF_FLAG_USE_SHORT_AD);
		else if (!strcmp(opt, "gid") && val)
			uopt->gid = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "umask") && val)
			uopt->umask = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "nostrict") && !val)
			uopt->flags &= ~(1 << UDF_FLAG_STRICT);
		else if (!strcmp(opt, "uid") && val)
			uopt->uid = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "session") && val)
			uopt->session = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "lastblock") && val)
			uopt->lastblock = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "anchor") && val)
			uopt->anchor = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "volume") && val)
			uopt->volume = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "partition") && val)
			uopt->partition = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "fileset") && val)
			uopt->fileset = simple_strtoul(val, NULL, 0);
		else if (!strcmp(opt, "rootdir") && val)
			uopt->rootdir = simple_strtoul(val, NULL, 0);
#ifdef CONFIG_NLS
		else if (!strcmp(opt, "iocharset") && val)
		{
			uopt->nls_map = load_nls(val);
			uopt->flags |= (1 << UDF_FLAG_NLS_MAP);
		}
#endif
		else if (!strcmp(opt, "utf8") && !val)
			uopt->flags |= (1 << UDF_FLAG_UTF8);
		else if (val)
		{
			printk(KERN_ERR "udf: bad mount option \"%s=%s\"\n",
				opt, val);
			return 0;
		}
		else
		{
			printk(KERN_ERR "udf: bad mount option \"%s\"\n",
				opt);
			return 0;
		}
	}
	return 1;
}

void
udf_write_super(struct super_block *sb)
{
	if (!(sb->s_flags & MS_RDONLY))
		udf_open_lvid(sb);
	sb->s_dirt = 0;
}

static int
udf_remount_fs(struct super_block *sb, int *flags, char *options)
{
	struct udf_options uopt;

	uopt.flags = UDF_SB(sb)->s_flags ;
	uopt.uid   = UDF_SB(sb)->s_uid ;
	uopt.gid   = UDF_SB(sb)->s_gid ;
	uopt.umask = UDF_SB(sb)->s_umask ;

	if ( !udf_parse_options(options, &uopt) )
		return -EINVAL;

	UDF_SB(sb)->s_flags = uopt.flags;
	UDF_SB(sb)->s_uid   = uopt.uid;
	UDF_SB(sb)->s_gid   = uopt.gid;
	UDF_SB(sb)->s_umask = uopt.umask;

#if UDFFS_RW != 1
	*flags |= MS_RDONLY;
#endif

	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
		return 0;
	if (*flags & MS_RDONLY)
		udf_close_lvid(sb);
	else
		udf_open_lvid(sb);

	return 0;
}

/*
 * udf_set_blocksize
 *
 * PURPOSE
 *	Set the block size to be used in all transfers.
 *
 * DESCRIPTION
 *	To allow room for a DMA transfer, it is best to guess big when unsure.
 *	This routine picks 2048 bytes as the blocksize when guessing. This
 *	should be adequate until devices with larger block sizes become common.
 *
 *	Note that the Linux kernel can currently only deal with blocksizes of
 *	512, 1024, 2048, 4096, and 8192 bytes.
 *
 * PRE-CONDITIONS
 *	sb			Pointer to _locked_ superblock.
 *
 * POST-CONDITIONS
 *	sb->s_blocksize		Blocksize.
 *	sb->s_blocksize_bits	log2 of blocksize.
 *	<return>	0	Blocksize is valid.
 *	<return>	1	Blocksize is invalid.
 *
 * HISTORY
 *	July 1, 1997 - Andrew E. Mileski
 *	Written, tested, and released.
 */
static  int
udf_set_blocksize(struct super_block *sb, int bsize)
{
	/* Use specified block size if specified */
	if (bsize)
		sb->s_blocksize = bsize;
	if (get_hardsect_size(sb->s_dev) > sb->s_blocksize)
		sb->s_blocksize = get_hardsect_size(sb->s_dev); 

	/* Block size must be an even multiple of 512 */
	switch (sb->s_blocksize)
	{
		case 512: sb->s_blocksize_bits = 9;	break;
		case 1024: sb->s_blocksize_bits = 10; break;
		case 2048: sb->s_blocksize_bits = 11; break;
		case 4096: sb->s_blocksize_bits = 12; break;
		case 8192: sb->s_blocksize_bits = 13; break;
		default:
		{
			udf_debug("Bad block size (%ld)\n", sb->s_blocksize);
			printk(KERN_ERR "udf: bad block size (%ld)\n", sb->s_blocksize);
			return 0;
		}
	}

	/* Set the block size */
	set_blocksize(sb->s_dev, sb->s_blocksize);
	return sb->s_blocksize;
}

static int
udf_vrs(struct super_block *sb, int silent)
{
	struct VolStructDesc *vsd = NULL;
	int sector = 32768;
	int sectorsize;
	struct buffer_head *bh = NULL;
	int iso9660=0;
	int nsr02=0;
	int nsr03=0;

	/* Block size must be a multiple of 512 */
	if (sb->s_blocksize & 511)
		return 0;

	if (sb->s_blocksize < sizeof(struct VolStructDesc))
		sectorsize = sizeof(struct VolStructDesc);
	else
		sectorsize = sb->s_blocksize;

	sector += (UDF_SB_SESSION(sb) << sb->s_blocksize_bits);

	udf_debug("Starting at sector %u (%ld byte sectors)\n",
		(sector >> sb->s_blocksize_bits), sb->s_blocksize);
	/* Process the sequence (if applicable) */
	for (;!nsr02 && !nsr03; sector += sectorsize)
	{
		/* Read a block */
		bh = udf_tread(sb, sector >> sb->s_blocksize_bits);
		if (!bh)
			break;

		/* Look for ISO  descriptors */
		vsd = (struct VolStructDesc *)(bh->b_data +
			(sector & (sb->s_blocksize - 1)));

		if (vsd->stdIdent[0] == 0)
		{
			udf_release_data(bh);
			break;
		}
		else if (!strncmp(vsd->stdIdent, STD_ID_CD001, STD_ID_LEN))
		{
			iso9660 = sector;
			switch (vsd->structType)
			{
				case 0: 
					udf_debug("ISO9660 Boot Record found\n");
					break;
				case 1: 
					udf_debug("ISO9660 Primary Volume Descriptor found\n");
					break;
				case 2: 
					udf_debug("ISO9660 Supplementary Volume Descriptor found\n");
					break;
				case 3: 
					udf_debug("ISO9660 Volume Partition Descriptor found\n");
					break;
				case 255: 
					udf_debug("ISO9660 Volume Descriptor Set Terminator found\n");
					break;
				default: 
					udf_debug("ISO9660 VRS (%u) found\n", vsd->structType);
					break;
			}
		}
		else if (!strncmp(vsd->stdIdent, STD_ID_BEA01, STD_ID_LEN))