namei.c

这是Linux系统下的对UDF文件系统新增的功能

		if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
		{
			block = UDF_I_LOCATION(dir).logicalBlockNum;
			fi = (struct fileIdentDesc *)(UDF_I_DATA(dir) + fibh->soffset - udf_ext0_offset(dir) + UDF_I_LENEATTR(dir));
		}
		else
		{
			block = eloc.logicalBlockNum + ((elen - 1) >>
				dir->i_sb->s_blocksize_bits);
			fi = (struct fileIdentDesc *)(fibh->sbh->b_data + fibh->soffset);
		}
	}
	else
	{
		fibh->soffset = fibh->eoffset - sb->s_blocksize;
		fibh->eoffset += nfidlen - sb->s_blocksize;
		if (fibh->sbh != fibh->ebh)
		{
			udf_release_data(fibh->sbh);
			fibh->sbh = fibh->ebh;
		}

		block = eloc.logicalBlockNum + ((elen - 1) >>
			dir->i_sb->s_blocksize_bits);

		if (!(fibh->ebh = udf_bread(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2), 1, err)))
		{
			udf_release_data(bh);
			udf_release_data(fibh->sbh);
			return NULL;
		}

		if (!(fibh->soffset))
		{
			if (udf_next_aext(dir, &bloc, &extoffset, &eloc, &elen, &bh, 1) ==
				(EXT_RECORDED_ALLOCATED >> 30))
			{
				block = eloc.logicalBlockNum + ((elen - 1) >>
					dir->i_sb->s_blocksize_bits);
			}
			else
				block ++;

			udf_release_data(fibh->sbh);
			fibh->sbh = fibh->ebh;
			fi = (struct fileIdentDesc *)(fibh->sbh->b_data);
		}
		else
		{
			fi = (struct fileIdentDesc *)
				(fibh->sbh->b_data + sb->s_blocksize + fibh->soffset);
		}
	}

	memset(cfi, 0, sizeof(struct fileIdentDesc));
	if (UDF_SB_UDFREV(sb) >= 0x0200)
		udf_new_tag((char *)cfi, TAG_IDENT_FID, 3, 1, block, sizeof(tag));
	else
		udf_new_tag((char *)cfi, TAG_IDENT_FID, 2, 1, block, sizeof(tag));
	cfi->fileVersionNum = cpu_to_le16(1);
	cfi->lengthFileIdent = namelen;
	cfi->lengthOfImpUse = cpu_to_le16(0);
	if (!udf_write_fi(dir, cfi, fi, fibh, NULL, name))
	{
		udf_release_data(bh);
		dir->i_size += nfidlen;
		if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
			UDF_I_LENALLOC(dir) += nfidlen;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
		dir->i_version = ++event;
#else
		dir->i_version = ++global_event;
#endif
		mark_inode_dirty(dir);
		return fi;
	}
	else
	{
		udf_release_data(bh);
		if (fibh->sbh != fibh->ebh)
			udf_release_data(fibh->ebh);
		udf_release_data(fibh->sbh);
		*err = -EIO;
		return NULL;
	}
}

static int udf_delete_entry(struct inode *inode, struct fileIdentDesc *fi,
	struct udf_fileident_bh *fibh, struct fileIdentDesc *cfi)
{
	cfi->fileCharacteristics |= FID_FILE_CHAR_DELETED;
	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT))
		memset(&(cfi->icb), 0x00, sizeof(long_ad));
	return udf_write_fi(inode, cfi, fi, fibh, NULL, NULL);
}

int udf_create(struct inode *dir, struct dentry *dentry, int mode)
{
	struct udf_fileident_bh fibh;
	struct inode *inode;
	struct fileIdentDesc cfi, *fi;
	int err;

	inode = udf_new_inode(dir, mode, &err);
	if (!inode)
		return err;

	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB)
		inode->i_op = &udf_file_inode_operations_adinicb;
	else
		inode->i_op = &udf_file_inode_operations;
	inode->i_mode = mode;
	mark_inode_dirty(inode);

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
	{
		inode->i_nlink --;
		mark_inode_dirty(inode);
		iput(inode);
		return err;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(uint32_t *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
	{
		mark_inode_dirty(dir);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
		dir->i_version = ++event;
#else
		dir->i_version = ++global_event;
#endif
	}
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	d_instantiate(dentry, inode);
	return 0;
}

int udf_mknod(struct inode * dir, struct dentry * dentry, int mode, int rdev)
{
	struct inode * inode;
	struct udf_fileident_bh fibh;
	int err;
	struct fileIdentDesc cfi, *fi;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,6)
	err = -ENAMETOOLONG;
	if (dentry->d_name.len >= UDF_NAME_LEN)
		goto out;
#endif

	err = -EIO;
	inode = udf_new_inode(dir, mode, &err);
	if (!inode)
		goto out;

	inode->i_uid = current->fsuid;
	inode->i_mode = mode;
	inode->i_op = NULL;
	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
	{
		inode->i_nlink --;
		mark_inode_dirty(inode);
		iput(inode);
		return err;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(uint32_t *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
	{
		mark_inode_dirty(dir);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
		dir->i_version = ++event;
#else
		dir->i_version = ++global_event;
#endif
	}
	if (S_ISREG(inode->i_mode))
	{
		if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB)
			inode->i_op = &udf_file_inode_operations_adinicb;
		else
			inode->i_op = &udf_file_inode_operations;
	}
	else if (S_ISCHR(inode->i_mode))
	{
		inode->i_op = &chrdev_inode_operations;
	} 
	else if (S_ISBLK(inode->i_mode))
	{
		inode->i_op = &blkdev_inode_operations;
	}
	else if (S_ISFIFO(inode->i_mode))
	{
		init_fifo(inode);
	}
	if (S_ISBLK(mode) || S_ISCHR(mode))
		inode->i_rdev = to_kdev_t(rdev);
	mark_inode_dirty(inode);

	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	d_instantiate(dentry, inode);
	err = 0;
out:
	return err;
}

int udf_mkdir(struct inode * dir, struct dentry * dentry, int mode)
{
	struct inode * inode;
	struct udf_fileident_bh fibh;
	int err;
	struct fileIdentDesc cfi, *fi;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,6)
	err = -ENAMETOOLONG;
	if (dentry->d_name.len >= UDF_NAME_LEN)
		goto out;
#endif

	err = -EMLINK;
	if (dir->i_nlink >= (256<<sizeof(dir->i_nlink))-1)
		goto out;

	err = -EIO;
	inode = udf_new_inode(dir, S_IFDIR, &err);
	if (!inode)
		goto out;

	inode->i_op = &udf_dir_inode_operations;
	if (!(fi = udf_add_entry(inode, NULL, &fibh, &cfi, &err)))
	{
		inode->i_nlink--;
		mark_inode_dirty(inode);
		iput(inode);
		goto out;
	}
	inode->i_nlink = 2;
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(dir));
	*(uint32_t *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(dir) & 0x00000000FFFFFFFFUL);
	cfi.fileCharacteristics = FID_FILE_CHAR_DIRECTORY | FID_FILE_CHAR_PARENT;
	udf_write_fi(inode, &cfi, fi, &fibh, NULL, NULL);
	udf_release_data(fibh.sbh);
	inode->i_mode = S_IFDIR | (mode & (S_IRWXUGO|S_ISVTX) & ~current->fs->umask);
	if (dir->i_mode & S_ISGID)
		inode->i_mode |= S_ISGID;
	mark_inode_dirty(inode);

	if (!(fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err)))
	{
		inode->i_nlink = 0;
		mark_inode_dirty(inode);
		iput(inode);
		goto out;
	}
	cfi.icb.extLength = cpu_to_le32(inode->i_sb->s_blocksize);
	cfi.icb.extLocation = cpu_to_lelb(UDF_I_LOCATION(inode));
	*(uint32_t *)((struct allocDescImpUse *)cfi.icb.impUse)->impUse =
		cpu_to_le32(UDF_I_UNIQUE(inode) & 0x00000000FFFFFFFFUL);
	cfi.fileCharacteristics |= FID_FILE_CHAR_DIRECTORY;
	udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
	dir->i_version = ++event;
#else
	dir->i_version = ++global_event;
#endif
	dir->i_nlink++;
	mark_inode_dirty(dir);
	d_instantiate(dentry, inode);
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	err = 0;
out:
	return err;
}

static int empty_dir(struct inode *dir)
{
	struct fileIdentDesc *fi, cfi;
	struct udf_fileident_bh fibh;
	loff_t f_pos;
	int size = (udf_ext0_offset(dir) + dir->i_size) >> 2;
	int block;
	lb_addr bloc, eloc;
	uint32_t extoffset, elen, offset;
	struct buffer_head *bh = NULL;

	f_pos = (udf_ext0_offset(dir) >> 2);

	fibh.soffset = fibh.eoffset = (f_pos & ((dir->i_sb->s_blocksize - 1) >> 2)) << 2;

	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB)
		fibh.sbh = fibh.ebh = NULL;
	else if (inode_bmap(dir, f_pos >> (dir->i_sb->s_blocksize_bits - 2),
		&bloc, &extoffset, &eloc, &elen, &offset, &bh) == (EXT_RECORDED_ALLOCATED >> 30))
	{
		offset >>= dir->i_sb->s_blocksize_bits;
		block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
		if ((++offset << dir->i_sb->s_blocksize_bits) < elen)
		{
			if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_SHORT)
				extoffset -= sizeof(short_ad);
			else if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_LONG)
				extoffset -= sizeof(long_ad);
		}
		else
			offset = 0;

		if (!(fibh.sbh = fibh.ebh = udf_tread(dir->i_sb, block)))
		{
			udf_release_data(bh);
			return 0;
		}
	}
	else
	{
		udf_release_data(bh);
		return 0;
	}

	while ( (f_pos < size) )
	{
		fi = udf_fileident_read(dir, &f_pos, &fibh, &cfi, &bloc, &extoffset, &eloc, &elen, &offset, &bh);

		if (!fi)
		{
			if (fibh.sbh != fibh.ebh)
				udf_release_data(fibh.ebh);
			udf_release_data(fibh.sbh);
			udf_release_data(bh);
			return 0;
		}

		if (cfi.lengthFileIdent && (cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) == 0)
		{
			if (fibh.sbh != fibh.ebh)
				udf_release_data(fibh.ebh);
			udf_release_data(fibh.sbh);
			udf_release_data(bh);
			return 0;
		}
	}
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
	udf_release_data(bh);
	return 1;
}

int udf_rmdir(struct inode * dir, struct dentry * dentry)
{
	int retval;
	struct inode * inode = dentry->d_inode;
	struct udf_fileident_bh fibh;
	struct fileIdentDesc *fi, cfi;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,6)
	retval = -ENAMETOOLONG;
	if (dentry->d_name.len >= UDF_NAME_LEN)
		goto out;
#endif

	retval = -ENOENT;
	fi = udf_find_entry(dir, dentry, &fibh, &cfi);
	if (!fi)
		goto out;

	DQUOT_INIT(inode);

	retval = -EIO;
	if (udf_get_lb_pblock(dir->i_sb, lelb_to_cpu(cfi.icb.extLocation), 0) != inode->i_ino)
		goto end_rmdir;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,6)
	if (!empty_dir(inode))
		retval = -ENOTEMPTY;
	else if (udf_get_lb_pblock(dir->i_sb, lelb_to_cpu(cfi.icb.extLocation), 0) !=
		inode->i_ino)
	{
		retval = -ENOENT;
	}
	else
	{
		retval = udf_delete_entry(dir, fi, &fibh, &cfi);
		dir->i_version = ++event;
	}
#else
	retval = -ENOTEMPTY;
	if (!empty_dir(inode))
		goto end_rmdir;
	retval = udf_delete_entry(dir, fi, &fibh, &cfi);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
	dir->i_version = ++event;
#else
	dir->i_version = ++global_event;
#endif
#endif
	if (retval)
		goto end_rmdir;
	if (inode->i_nlink != 2)
		udf_warning(inode->i_sb, "udf_rmdir",
			"empty directory has nlink != 2 (%d)",
			inode->i_nlink);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,14)
	inode->i_version = ++event;
#else
	inode->i_version = ++global_event;
#endif
	inode->i_nlink = 0;
	inode->i_size = 0;
	mark_inode_dirty(inode);
	dir->i_nlink --;
	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
	UDF_I_UCTIME(inode) = UDF_I_UCTIME(dir) = UDF_I_UMTIME(dir) = CURRENT_UTIME;
	mark_inode_dirty(dir);
	d_delete(dentry);

end_rmdir:
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
out:
	return retval;
}

int udf_unlink(struct inode * dir, struct dentry * dentry)
{
	int retval;
	struct inode * inode = dentry->d_inode;
	struct udf_fileident_bh fibh;
	struct fileIdentDesc *fi;
	struct fileIdentDesc cfi;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,2,6)
	retval = -ENAMETOOLONG;
	if (dentry->d_name.len >= UDF_NAME_LEN)
		goto out;
#endif

	retval = -ENOENT;
	fi = udf_find_entry(dir, dentry, &fibh, &cfi);
	if (!fi)
		goto out;

	DQUOT_INIT(inode);

	retval = -EIO;

	if (udf_get_lb_pblock(dir->i_sb, lelb_to_cpu(cfi.icb.extLocation), 0) !=
		inode->i_ino)
	{
		goto end_unlink;
	}

	if (!inode->i_nlink)
	{
		udf_debug("Deleting nonexistent file (%lu), %d\n",
			inode->i_ino, inode->i_nlink);
		inode->i_nlink = 1;
	}
	retval = udf_delete_entry(dir, fi, &fibh, &cfi);
	if (retval)
		goto end_unlink;
	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
	UDF_I_UCTIME(dir) = UDF_I_UMTIME(dir) = CURRENT_UTIME;
	mark_inode_dirty(dir);
	inode->i_nlink--;
	mark_inode_dirty(inode);
	inode->i_ctime = dir->i_ctime;
	retval = 0;
	d_delete(dentry);	/* This also frees the inode */

end_unlink:
	if (fibh.sbh != fibh.ebh)
		udf_release_data(fibh.ebh);
	udf_release_data(fibh.sbh);
out:
	return retval;
}

int udf_symlink(struct inode * dir, struct dentry * dentry, const char * symname)
{
	struct inode * inode;
	struct pathComponent *pc;
	char *compstart;
	struct udf_fileident_bh fibh;
	struct buffer_head *bh = NULL;
	int eoffset, elen = 0;
	struct fileIdentDesc *fi;
	struct fileIdentDesc cfi;
	char *ea;
	int err;
	int block;
	char name[UDF_NAME_LEN];
	int namelen;

	if (!(inode = udf_new_inode(dir, S_IFLNK, &err)))
		goto out;

	inode->i_mode = S_IFLNK | S_IRWXUGO;
	inode->i_op = &udf_symlink_inode_operations;

	if (UDF_I_ALLOCTYPE(inode) != ICBTAG_FLAG_AD_IN_ICB)
	{
		struct buffer_head *bh = NULL;
		lb_addr bloc, eloc;
		uint32_t elen, extoffset;

		block = udf_new_block(inode->i_sb, inode,
			UDF_I_LOCATION(inode).partitionReferenceNum,
			UDF_I_LOCATION(inode).logicalBlockNum, &err);
		if (!block)
			goto out_no_entry;
		bloc = UDF_I_LOCATION(inode);
		eloc.logicalBlockNum = block;
		eloc.partitionReferenceNum = UDF_I_LOCATION(inode).partitionReferenceNum;
		elen = inode->i_sb->s_blocksize;
		UDF_I_LENEXTENTS(inode) = elen;
		extoffset = udf_file_entry_alloc_offset(inode);
		udf_add_aext(inode, &bloc, &extoffset, eloc, elen, &bh, 0);
		udf_release_data(bh);

		inode->i_blocks = inode->i_sb->s_blocksize / 512;
		block = udf_get_pblock(inode->i_sb, block,
			UDF_I_LOCATION(inode).partitionReferenceNum, 0);
		bh = udf_tread(inode->i_sb, block);
		ea = bh->b_data + udf_ext0_offset(inode);
	}
	else
		ea = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);

	eoffset = inode->i_sb->s_blocksize - udf_ext0_offset(inode);
	pc = (struct pathComponent *)ea;

	if (*symname == '/')