fs.c

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

			if (*value) {
				printk(KERN_ERR "NTFS: umask invalid "
						"argument\n");
				return 0;
			}
		} else if (strcmp(opt, "mft_zone_multiplier") == 0) {
			unsigned long ul;

			if (!value || !*value)
				goto needs_arg;
			ul = simple_strtoul(value, &value, 0);
			if (*value) {
				printk(KERN_ERR "NTFS: mft_zone_multiplier "
						"invalid argument\n");
				return 0;
			}
			if (ul >= 1 && ul <= 4)
				mft_zone_mul = ul;
			else {
				mft_zone_mul = 1;
				printk(KERN_WARNING "NTFS: mft_zone_multiplier "
					      "out of range. Setting to 1.\n");
			}
		} else if (strcmp(opt, "posix") == 0) {
			int val;
			if (!value || !*value)
				goto needs_arg;
			if (!simple_getbool(value, &val))
				goto needs_bool;
			ngt = val ? ngt_posix : ngt_nt;
		} else if (strcmp(opt, "show_sys_files") == 0) {
			int val = 0;
			if (!value || !*value)
				val = 1;
			else if (!simple_getbool(value, &val))
				goto needs_bool;
			ngt = val ? ngt_full : ngt_nt;
		} else if (strcmp(opt, "iocharset") == 0) {
			if (!value || !*value)
				goto needs_arg;
			nls_map = load_nls(value);
			if (!nls_map) {
				printk(KERN_ERR "NTFS: charset not found");
				return 0;
			}
		} else if (strcmp(opt, "utf8") == 0) {
			int val = 0;
			if (!value || !*value)
				val = 1;
			else if (!simple_getbool(value, &val))
				goto needs_bool;
			use_utf8 = val;
		} else {
			printk(KERN_ERR "NTFS: unkown option '%s'\n", opt);
			return 0;
		}
	}
done:
	if (use_utf8 == -1) {
		/* utf8 was not specified at all. */
		if (!nls_map) {
			/*
			 * No NLS was specified. If first mount, load the
			 * default NLS, otherwise don't change the NLS setting.
			 */
			if (vol->nls_map == (void*)-1)
				vol->nls_map = load_nls_default();
		} else {
			/* If an NLS was already loaded, unload it first. */
			if (vol->nls_map && vol->nls_map != (void*)-1)
				unload_nls(vol->nls_map);
			/* Use the specified NLS. */
			vol->nls_map = nls_map;
		}
	} else {
		/* utf8 was specified. */
		if (use_utf8 && nls_map) {
			unload_nls(nls_map);
			printk(KERN_ERR "NTFS: utf8 cannot be combined with "
					"iocharset.\n");
			return 0;
		}
		/* If an NLS was already loaded, unload it first. */
		if (vol->nls_map && vol->nls_map != (void*)-1)
			unload_nls(vol->nls_map);
		if (!use_utf8) {
			/* utf8 was specified as false. */
			if (!nls_map)
				/* No NLS was specified, load the default. */
				vol->nls_map = load_nls_default();
			else
				/* Use the specified NLS. */
				vol->nls_map = nls_map;
		} else
			/* utf8 was specified as true. */
			vol->nls_map = NULL;
	}
	if (uid != -1)
		vol->uid = uid;
	if (gid != -1)
		vol->gid = gid;
	if (umask != -1)
		vol->umask = (ntmode_t)umask;
	if (ngt != -1)
		vol->ngt = ngt;
	if (mft_zone_mul != -1) {
		/* mft_zone_multiplier was specified. */
		if (vol->mft_zone_multiplier != -1) {
			/* This is a remount, ignore a change and warn user. */
			if (vol->mft_zone_multiplier != mft_zone_mul)
				printk(KERN_WARNING "NTFS: Ignoring changes in "
						"mft_zone_multiplier on "
						"remount. If you want to "
						"change this you need to "
						"umount and mount again.\n");
		} else
			/* Use the specified multiplier. */
			vol->mft_zone_multiplier = mft_zone_mul;
	} else if (vol->mft_zone_multiplier == -1)
		/* No multiplier specified and first mount, so set default. */
		vol->mft_zone_multiplier = 1;
	return 1;
needs_arg:
	printk(KERN_ERR "NTFS: %s needs an argument", opt);
	return 0;
needs_bool:
	printk(KERN_ERR "NTFS: %s needs boolean argument", opt);
	return 0;
}
			
static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *d)
{
	struct inode *res = 0;
	char *item = 0;
	ntfs_iterate_s walk;
	int err;
	
	ntfs_debug(DEBUG_NAME1, __FUNCTION__ "(): Looking up %s in directory "
			"ino 0x%x.\n", d->d_name.name, (unsigned)dir->i_ino);
	walk.name = NULL;
	walk.namelen = 0;
	/* Convert to wide string. */
	err = ntfs_decodeuni(NTFS_INO2VOL(dir), (char*)d->d_name.name,
			       d->d_name.len, &walk.name, &walk.namelen);
	if (err)
		goto err_ret;
	item = ntfs_malloc(ITEM_SIZE);
	if (!item) {
		err = -ENOMEM;
		goto err_ret;
	}
	/* ntfs_getdir will place the directory entry into item, and the first
	 * long long is the MFT record number. */
	walk.type = BY_NAME;
	walk.dir = NTFS_LINO2NINO(dir);
	walk.result = item;
	if (ntfs_getdir_byname(&walk))
		res = iget(dir->i_sb, NTFS_GETU32(item));
	d_add(d, res);
	ntfs_free(item);
	ntfs_free(walk.name);
	/* Always return success, the dcache will handle negative entries. */
	return NULL;
err_ret:
	ntfs_free(walk.name);
	return ERR_PTR(err);
}

static struct file_operations ntfs_file_operations = {
	llseek:		generic_file_llseek,
	read:		ntfs_read,
#ifdef CONFIG_NTFS_RW
	write:		ntfs_write,
#endif
	open:		generic_file_open,
};

static struct inode_operations ntfs_inode_operations;

#ifdef CONFIG_NTFS_RW
static int ntfs_create(struct inode* dir, struct dentry *d, int mode)
{
	struct inode *r = 0;
	ntfs_inode *ino = 0;
	ntfs_volume *vol;
	int error = 0;
	ntfs_attribute *si;

	r = new_inode(dir->i_sb);
	if (!r) {
		error = -ENOMEM;
		goto fail;
	}
	ntfs_debug(DEBUG_OTHER, "ntfs_create %s\n", d->d_name.name);
	vol = NTFS_INO2VOL(dir);
	ino = NTFS_LINO2NINO(r);
	error = ntfs_alloc_file(NTFS_LINO2NINO(dir), ino, (char*)d->d_name.name,
				d->d_name.len);
	if (error) {
		ntfs_error("ntfs_alloc_file FAILED: error = %i", error);
		goto fail;
	}
	/* Not doing this one was causing a huge amount of corruption! Now the
	 * bugger bytes the dust! (-8 (AIA) */
	r->i_ino = ino->i_number;
	error = ntfs_update_inode(ino);
	if (error)
		goto fail;
	error = ntfs_update_inode(NTFS_LINO2NINO(dir));
	if (error)
		goto fail;
	r->i_uid = vol->uid;
	r->i_gid = vol->gid;
	/* FIXME: dirty? dev? */
	/* Get the file modification times from the standard information. */
	si = ntfs_find_attr(ino, vol->at_standard_information, NULL);
	if (si) {
		char *attr = si->d.data;
		r->i_atime = ntfs_ntutc2unixutc(NTFS_GETU64(attr + 0x18));
		r->i_ctime = ntfs_ntutc2unixutc(NTFS_GETU64(attr));
		r->i_mtime = ntfs_ntutc2unixutc(NTFS_GETU64(attr + 8));
	}
	/* It's not a directory */
	r->i_op = &ntfs_inode_operations;
	r->i_fop = &ntfs_file_operations;
	r->i_mode = S_IFREG | S_IRUGO;
#ifdef CONFIG_NTFS_RW
	r->i_mode |= S_IWUGO;
#endif
	r->i_mode &= ~vol->umask;
	insert_inode_hash(r);
	d_instantiate(d, r);
	return 0;
 fail:
	if (r)
		iput(r);
	return error;
}

static int _linux_ntfs_mkdir(struct inode *dir, struct dentry* d, int mode)
{
	int error;
	struct inode *r = 0;
	ntfs_volume *vol;
	ntfs_inode *ino;
	ntfs_attribute *si;

	ntfs_debug (DEBUG_DIR1, "mkdir %s in %x\n", d->d_name.name, dir->i_ino);
	error = -ENAMETOOLONG;
	if (d->d_name.len > /* FIXME: */ 255)
		goto out;
	error = -EIO;
	r = new_inode(dir->i_sb);
	if (!r)
		goto out;
	vol = NTFS_INO2VOL(dir);
	ino = NTFS_LINO2NINO(r);
	error = ntfs_mkdir(NTFS_LINO2NINO(dir), d->d_name.name, d->d_name.len,
			   ino);
	if (error)
		goto out;
	/* Not doing this one was causing a huge amount of corruption! Now the
	 * bugger bytes the dust! (-8 (AIA) */
	r->i_ino = ino->i_number;
	r->i_uid = vol->uid;
	r->i_gid = vol->gid;
	si = ntfs_find_attr(ino, vol->at_standard_information, NULL);
	if (si) {
		char *attr = si->d.data;
		r->i_atime = ntfs_ntutc2unixutc(NTFS_GETU64(attr + 0x18));
		r->i_ctime = ntfs_ntutc2unixutc(NTFS_GETU64(attr));
		r->i_mtime = ntfs_ntutc2unixutc(NTFS_GETU64(attr + 8));
	}
	/* It's a directory. */
	r->i_op = &ntfs_dir_inode_operations;
	r->i_fop = &ntfs_dir_operations;
	r->i_mode = S_IFDIR | S_IRUGO | S_IXUGO;
#ifdef CONFIG_NTFS_RW
	r->i_mode |= S_IWUGO;
#endif
	r->i_mode &= ~vol->umask;	
	
	insert_inode_hash(r);
	d_instantiate(d, r);
	error = 0;
 out:
 	ntfs_debug (DEBUG_DIR1, "mkdir returns %d\n", error);
	return error;
}
#endif

static struct file_operations ntfs_dir_operations = {
	read:		generic_read_dir,
	readdir:	ntfs_readdir,
};

static struct inode_operations ntfs_dir_inode_operations = {
	lookup:		ntfs_lookup,
#ifdef CONFIG_NTFS_RW
	create:		ntfs_create,
	mkdir:		_linux_ntfs_mkdir,
#endif
};

/* ntfs_read_inode() is called by the Virtual File System (the kernel layer 
 * that deals with filesystems) when iget is called requesting an inode not
 * already present in the inode table. Typically filesystems have separate
 * inode_operations for directories, files and symlinks. */
static void ntfs_read_inode(struct inode* inode)
{
	ntfs_volume *vol;
	ntfs_inode *ino;
	ntfs_attribute *data;
	ntfs_attribute *si;

	vol = NTFS_INO2VOL(inode);
	inode->i_mode = 0;
	ntfs_debug(DEBUG_OTHER, "ntfs_read_inode 0x%lx\n", inode->i_ino);
	switch (inode->i_ino) {
		/* Those are loaded special files. */
	case FILE_Mft:
		if (!vol->mft_ino || ((vol->ino_flags & 1) == 0))
			goto sys_file_error;
		ntfs_memcpy(&inode->u.ntfs_i, vol->mft_ino, sizeof(ntfs_inode));
		ino = vol->mft_ino;
		vol->mft_ino = &inode->u.ntfs_i;
		vol->ino_flags &= ~1;
		ntfs_free(ino);
		ino = vol->mft_ino;
		ntfs_debug(DEBUG_OTHER, "Opening $MFT!\n");
		break;
	case FILE_MftMirr:
		if (!vol->mftmirr || ((vol->ino_flags & 2) == 0))
			goto sys_file_error;
		ntfs_memcpy(&inode->u.ntfs_i, vol->mftmirr, sizeof(ntfs_inode));
		ino = vol->mftmirr;
		vol->mftmirr = &inode->u.ntfs_i;
		vol->ino_flags &= ~2;
		ntfs_free(ino);
		ino = vol->mftmirr;
		ntfs_debug(DEBUG_OTHER, "Opening $MFTMirr!\n");
		break;
	case FILE_BitMap:
		if (!vol->bitmap || ((vol->ino_flags & 4) == 0))
			goto sys_file_error;
		ntfs_memcpy(&inode->u.ntfs_i, vol->bitmap, sizeof(ntfs_inode));
		ino = vol->bitmap;
		vol->bitmap = &inode->u.ntfs_i;
		vol->ino_flags &= ~4;
		ntfs_free(ino);
		ino = vol->bitmap;
		ntfs_debug(DEBUG_OTHER, "Opening $Bitmap!\n");
		break;
	case FILE_LogFile ... FILE_AttrDef:
	/* No need to log root directory accesses. */
	case FILE_Boot ... FILE_UpCase:
		ntfs_debug(DEBUG_OTHER, "Opening system file %i!\n",
				inode->i_ino);
	default:
		ino = &inode->u.ntfs_i;
		if (!ino || ntfs_init_inode(ino, NTFS_INO2VOL(inode),
								inode->i_ino))
		{
			ntfs_debug(DEBUG_OTHER, "NTFS: Error loading inode "
					"0x%x\n", (unsigned int)inode->i_ino);
			return;
		}
	}
	/* Set uid/gid from mount options */
	inode->i_uid = vol->uid;
	inode->i_gid = vol->gid;
	inode->i_nlink = 1;
	/* Use the size of the data attribute as file size */
	data = ntfs_find_attr(ino, vol->at_data, NULL);
	if (!data)
		inode->i_size = 0;
	else
		inode->i_size = data->size;
	/* Get the file modification times from the standard information. */
	si = ntfs_find_attr(ino, vol->at_standard_information, NULL);
	if (si) {
		char *attr = si->d.data;
		inode->i_atime = ntfs_ntutc2unixutc(NTFS_GETU64(attr + 0x18));
		inode->i_ctime = ntfs_ntutc2unixutc(NTFS_GETU64(attr));
		inode->i_mtime = ntfs_ntutc2unixutc(NTFS_GETU64(attr + 8));
	}
	/* If it has an index root, it's a directory. */
	if (ntfs_find_attr(ino, vol->at_index_root, "$I30")) {
		ntfs_attribute *at;