inode.c

linux 内核源代码

/*
 *  linux/fs/isofs/inode.c
 *
 *  (C) 1991  Linus Torvalds - minix filesystem
 *      1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
 *      1994  Eberhard Mönkeberg - multi session handling.
 *      1995  Mark Dobie - allow mounting of some weird VideoCDs and PhotoCDs.
 *	1997  Gordon Chaffee - Joliet CDs
 *	1998  Eric Lammerts - ISO 9660 Level 3
 *	2004  Paul Serice - Inode Support pushed out from 4GB to 128GB
 *	2004  Paul Serice - NFS Export Operations
 */

#include <linux/init.h>
#include <linux/module.h>

#include <linux/slab.h>
#include <linux/nls.h>
#include <linux/ctype.h>
#include <linux/smp_lock.h>
#include <linux/statfs.h>
#include <linux/cdrom.h>
#include <linux/parser.h>

#include "isofs.h"
#include "zisofs.h"

#define BEQUIET

static int isofs_hashi(struct dentry *parent, struct qstr *qstr);
static int isofs_hash(struct dentry *parent, struct qstr *qstr);
static int isofs_dentry_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b);
static int isofs_dentry_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b);

#ifdef CONFIG_JOLIET
static int isofs_hashi_ms(struct dentry *parent, struct qstr *qstr);
static int isofs_hash_ms(struct dentry *parent, struct qstr *qstr);
static int isofs_dentry_cmpi_ms(struct dentry *dentry, struct qstr *a, struct qstr *b);
static int isofs_dentry_cmp_ms(struct dentry *dentry, struct qstr *a, struct qstr *b);
#endif

static void isofs_put_super(struct super_block *sb)
{
	struct isofs_sb_info *sbi = ISOFS_SB(sb);
#ifdef CONFIG_JOLIET
	if (sbi->s_nls_iocharset) {
		unload_nls(sbi->s_nls_iocharset);
		sbi->s_nls_iocharset = NULL;
	}
#endif

	kfree(sbi);
	sb->s_fs_info = NULL;
	return;
}

static void isofs_read_inode(struct inode *);
static int isofs_statfs (struct dentry *, struct kstatfs *);

static struct kmem_cache *isofs_inode_cachep;

static struct inode *isofs_alloc_inode(struct super_block *sb)
{
	struct iso_inode_info *ei;
	ei = kmem_cache_alloc(isofs_inode_cachep, GFP_KERNEL);
	if (!ei)
		return NULL;
	return &ei->vfs_inode;
}

static void isofs_destroy_inode(struct inode *inode)
{
	kmem_cache_free(isofs_inode_cachep, ISOFS_I(inode));
}

static void init_once(struct kmem_cache *cachep, void *foo)
{
	struct iso_inode_info *ei = foo;

	inode_init_once(&ei->vfs_inode);
}

static int init_inodecache(void)
{
	isofs_inode_cachep = kmem_cache_create("isofs_inode_cache",
					sizeof(struct iso_inode_info),
					0, (SLAB_RECLAIM_ACCOUNT|
					SLAB_MEM_SPREAD),
					init_once);
	if (isofs_inode_cachep == NULL)
		return -ENOMEM;
	return 0;
}

static void destroy_inodecache(void)
{
	kmem_cache_destroy(isofs_inode_cachep);
}

static int isofs_remount(struct super_block *sb, int *flags, char *data)
{
	/* we probably want a lot more here */
	*flags |= MS_RDONLY;
	return 0;
}

static const struct super_operations isofs_sops = {
	.alloc_inode	= isofs_alloc_inode,
	.destroy_inode	= isofs_destroy_inode,
	.read_inode	= isofs_read_inode,
	.put_super	= isofs_put_super,
	.statfs		= isofs_statfs,
	.remount_fs	= isofs_remount,
};


static struct dentry_operations isofs_dentry_ops[] = {
	{
		.d_hash		= isofs_hash,
		.d_compare	= isofs_dentry_cmp,
	},
	{
		.d_hash		= isofs_hashi,
		.d_compare	= isofs_dentry_cmpi,
	},
#ifdef CONFIG_JOLIET
	{
		.d_hash		= isofs_hash_ms,
		.d_compare	= isofs_dentry_cmp_ms,
	},
	{
		.d_hash		= isofs_hashi_ms,
		.d_compare	= isofs_dentry_cmpi_ms,
	},
#endif
};

struct iso9660_options{
	char map;
	char rock;
	char joliet;
	char cruft;
	char hide;
	char showassoc;
	char nocompress;
	unsigned char check;
	unsigned int blocksize;
	mode_t mode;
	gid_t gid;
	uid_t uid;
	char *iocharset;
	unsigned char utf8;
	/* LVE */
	s32 session;
	s32 sbsector;
};

/*
 * Compute the hash for the isofs name corresponding to the dentry.
 */
static int
isofs_hash_common(struct dentry *dentry, struct qstr *qstr, int ms)
{
	const char *name;
	int len;

	len = qstr->len;
	name = qstr->name;
	if (ms) {
		while (len && name[len-1] == '.')
			len--;
	}

	qstr->hash = full_name_hash(name, len);

	return 0;
}

/*
 * Compute the hash for the isofs name corresponding to the dentry.
 */
static int
isofs_hashi_common(struct dentry *dentry, struct qstr *qstr, int ms)
{
	const char *name;
	int len;
	char c;
	unsigned long hash;

	len = qstr->len;
	name = qstr->name;
	if (ms) {
		while (len && name[len-1] == '.')
			len--;
	}

	hash = init_name_hash();
	while (len--) {
		c = tolower(*name++);
		hash = partial_name_hash(c, hash);
	}
	qstr->hash = end_name_hash(hash);

	return 0;
}

/*
 * Case insensitive compare of two isofs names.
 */
static int isofs_dentry_cmpi_common(struct dentry *dentry, struct qstr *a,
				struct qstr *b, int ms)
{
	int alen, blen;

	/* A filename cannot end in '.' or we treat it like it has none */
	alen = a->len;
	blen = b->len;
	if (ms) {
		while (alen && a->name[alen-1] == '.')
			alen--;
		while (blen && b->name[blen-1] == '.')
			blen--;
	}
	if (alen == blen) {
		if (strnicmp(a->name, b->name, alen) == 0)
			return 0;
	}
	return 1;
}

/*
 * Case sensitive compare of two isofs names.
 */
static int isofs_dentry_cmp_common(struct dentry *dentry, struct qstr *a,
					struct qstr *b, int ms)
{
	int alen, blen;

	/* A filename cannot end in '.' or we treat it like it has none */
	alen = a->len;
	blen = b->len;
	if (ms) {
		while (alen && a->name[alen-1] == '.')
			alen--;
		while (blen && b->name[blen-1] == '.')
			blen--;
	}
	if (alen == blen) {
		if (strncmp(a->name, b->name, alen) == 0)
			return 0;
	}
	return 1;
}

static int
isofs_hash(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hash_common(dentry, qstr, 0);
}

static int
isofs_hashi(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hashi_common(dentry, qstr, 0);
}

static int
isofs_dentry_cmp(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_dentry_cmp_common(dentry, a, b, 0);
}

static int
isofs_dentry_cmpi(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_dentry_cmpi_common(dentry, a, b, 0);
}

#ifdef CONFIG_JOLIET
static int
isofs_hash_ms(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hash_common(dentry, qstr, 1);
}

static int
isofs_hashi_ms(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hashi_common(dentry, qstr, 1);
}

static int
isofs_dentry_cmp_ms(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_dentry_cmp_common(dentry, a, b, 1);
}

static int
isofs_dentry_cmpi_ms(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_dentry_cmpi_common(dentry, a, b, 1);
}
#endif

enum {
	Opt_block, Opt_check_r, Opt_check_s, Opt_cruft, Opt_gid, Opt_ignore,
	Opt_iocharset, Opt_map_a, Opt_map_n, Opt_map_o, Opt_mode, Opt_nojoliet,
	Opt_norock, Opt_sb, Opt_session, Opt_uid, Opt_unhide, Opt_utf8, Opt_err,
	Opt_nocompress, Opt_hide, Opt_showassoc,
};

static match_table_t tokens = {
	{Opt_norock, "norock"},
	{Opt_nojoliet, "nojoliet"},
	{Opt_unhide, "unhide"},
	{Opt_hide, "hide"},
	{Opt_showassoc, "showassoc"},
	{Opt_cruft, "cruft"},
	{Opt_utf8, "utf8"},
	{Opt_iocharset, "iocharset=%s"},
	{Opt_map_a, "map=acorn"},
	{Opt_map_a, "map=a"},
	{Opt_map_n, "map=normal"},
	{Opt_map_n, "map=n"},
	{Opt_map_o, "map=off"},
	{Opt_map_o, "map=o"},
	{Opt_session, "session=%u"},
	{Opt_sb, "sbsector=%u"},
	{Opt_check_r, "check=relaxed"},
	{Opt_check_r, "check=r"},
	{Opt_check_s, "check=strict"},
	{Opt_check_s, "check=s"},
	{Opt_uid, "uid=%u"},
	{Opt_gid, "gid=%u"},
	{Opt_mode, "mode=%u"},
	{Opt_block, "block=%u"},
	{Opt_ignore, "conv=binary"},
	{Opt_ignore, "conv=b"},
	{Opt_ignore, "conv=text"},
	{Opt_ignore, "conv=t"},
	{Opt_ignore, "conv=mtext"},
	{Opt_ignore, "conv=m"},
	{Opt_ignore, "conv=auto"},
	{Opt_ignore, "conv=a"},
	{Opt_nocompress, "nocompress"},
	{Opt_err, NULL}
};

static int parse_options(char *options, struct iso9660_options *popt)
{
	char *p;
	int option;

	popt->map = 'n';
	popt->rock = 'y';
	popt->joliet = 'y';
	popt->cruft = 'n';
	popt->hide = 'n';
	popt->showassoc = 'n';
	popt->check = 'u';		/* unset */
	popt->nocompress = 0;
	popt->blocksize = 1024;
	popt->mode = S_IRUGO | S_IXUGO; /*
					 * r-x for all.  The disc could
					 * be shared with DOS machines so
					 * virtually anything could be
					 * a valid executable.
					 */
	popt->gid = 0;
	popt->uid = 0;
	popt->iocharset = NULL;
	popt->utf8 = 0;
	popt->session=-1;
	popt->sbsector=-1;
	if (!options)
		return 1;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;
		substring_t args[MAX_OPT_ARGS];
		unsigned n;

		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_norock:
			popt->rock = 'n';
			break;
		case Opt_nojoliet:
			popt->joliet = 'n';
			break;
		case Opt_hide:
			popt->hide = 'y';
			break;
		case Opt_unhide:
		case Opt_showassoc:
			popt->showassoc = 'y';
			break;
		case Opt_cruft:
			popt->cruft = 'y';
			break;
		case Opt_utf8:
			popt->utf8 = 1;
			break;
#ifdef CONFIG_JOLIET
		case Opt_iocharset:
			popt->iocharset = match_strdup(&args[0]);
			break;
#endif
		case Opt_map_a:
			popt->map = 'a';
			break;
		case Opt_map_o:
			popt->map = 'o';
			break;
		case Opt_map_n:
			popt->map = 'n';
			break;
		case Opt_session:
			if (match_int(&args[0], &option))
				return 0;
			n = option;
			if (n > 99)
				return 0;
			popt->session = n + 1;
			break;
		case Opt_sb:
			if (match_int(&args[0], &option))
				return 0;
			popt->sbsector = option;
			break;
		case Opt_check_r:
			popt->check = 'r';
			break;
		case Opt_check_s:
			popt->check = 's';
			break;
		case Opt_ignore:
			break;
		case Opt_uid:
			if (match_int(&args[0], &option))
				return 0;
			popt->uid = option;
			break;
		case Opt_gid:
			if (match_int(&args[0], &option))
				return 0;
			popt->gid = option;
			break;
		case Opt_mode:
			if (match_int(&args[0], &option))
				return 0;
			popt->mode = option;
			break;
		case Opt_block:
			if (match_int(&args[0], &option))
				return 0;
			n = option;
			if (n != 512 && n != 1024 && n != 2048)
				return 0;
			popt->blocksize = n;
			break;
		case Opt_nocompress:
			popt->nocompress = 1;
			break;
		default:
			return 0;
		}
	}
	return 1;
}

/*
 * look if the driver can tell the multi session redirection value
 *
 * don't change this if you don't know what you do, please!
 * Multisession is legal only with XA disks.
 * A non-XA disk with more than one volume descriptor may do it right, but
 * usually is written in a nowhere standardized "multi-partition" manner.
 * Multisession uses absolute addressing (solely the first frame of the whole
 * track is #0), multi-partition uses relative addressing (each first frame of
 * each track is #0), and a track is not a session.
 *
 * A broken CDwriter software or drive firmware does not set new standards,
 * at least not if conflicting with the existing ones.
 *
 * [e-mail]
 */