inode.c

linux 内核源代码

	if (rc) {
		rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
		if (rc) {
			printk(KERN_DEBUG "Valid metadata not found in header "
			       "region or xattr region; treating file as "
			       "unencrypted\n");
			rc = 0;
			kmem_cache_free(ecryptfs_header_cache_2, page_virt);
			goto out;
		}
		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
	}
	mount_crypt_stat = &ecryptfs_superblock_to_private(
		dentry->d_sb)->mount_crypt_stat;
	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
			file_size = ((crypt_stat->extent_size
				      * crypt_stat->num_header_extents_at_front)
				     + i_size_read(lower_dentry->d_inode));
		else
			file_size = i_size_read(lower_dentry->d_inode);
	} else {
		memcpy(&file_size, page_virt, sizeof(file_size));
		file_size = be64_to_cpu(file_size);
	}
	i_size_write(dentry->d_inode, (loff_t)file_size);
	kmem_cache_free(ecryptfs_header_cache_2, page_virt);
	goto out;

out_dput:
	dput(lower_dentry);
	d_drop(dentry);
out:
	return ERR_PTR(rc);
}

static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
			 struct dentry *new_dentry)
{
	struct dentry *lower_old_dentry;
	struct dentry *lower_new_dentry;
	struct dentry *lower_dir_dentry;
	u64 file_size_save;
	int rc;

	file_size_save = i_size_read(old_dentry->d_inode);
	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
	dget(lower_old_dentry);
	dget(lower_new_dentry);
	lower_dir_dentry = lock_parent(lower_new_dentry);
	rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
		      lower_new_dentry);
	if (rc || !lower_new_dentry->d_inode)
		goto out_lock;
	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
	if (rc)
		goto out_lock;
	fsstack_copy_attr_times(dir, lower_new_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_new_dentry->d_inode);
	old_dentry->d_inode->i_nlink =
		ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
	i_size_write(new_dentry->d_inode, file_size_save);
out_lock:
	unlock_dir(lower_dir_dentry);
	dput(lower_new_dentry);
	dput(lower_old_dentry);
	d_drop(lower_old_dentry);
	d_drop(new_dentry);
	d_drop(old_dentry);
	return rc;
}

static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
{
	int rc = 0;
	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
	struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);

	lock_parent(lower_dentry);
	rc = vfs_unlink(lower_dir_inode, lower_dentry);
	if (rc) {
		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
		goto out_unlock;
	}
	fsstack_copy_attr_times(dir, lower_dir_inode);
	dentry->d_inode->i_nlink =
		ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
	dentry->d_inode->i_ctime = dir->i_ctime;
	d_drop(dentry);
out_unlock:
	unlock_parent(lower_dentry);
	return rc;
}

static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
			    const char *symname)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;
	umode_t mode;
	char *encoded_symname;
	int encoded_symlen;
	struct ecryptfs_crypt_stat *crypt_stat = NULL;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	dget(lower_dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	mode = S_IALLUGO;
	encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
						  strlen(symname),
						  &encoded_symname);
	if (encoded_symlen < 0) {
		rc = encoded_symlen;
		goto out_lock;
	}
	rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
			 encoded_symname, mode);
	kfree(encoded_symname);
	if (rc || !lower_dentry->d_inode)
		goto out_lock;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out_lock;
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
out_lock:
	unlock_dir(lower_dir_dentry);
	dput(lower_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
	if (rc || !lower_dentry->d_inode)
		goto out;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out;
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
out:
	unlock_dir(lower_dir_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
{
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;
	int rc;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	dget(dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	dget(lower_dentry);
	rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
	dput(lower_dentry);
	if (!rc)
		d_delete(lower_dentry);
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
	unlock_dir(lower_dir_dentry);
	if (!rc)
		d_drop(dentry);
	dput(dentry);
	return rc;
}

static int
ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_dir_dentry = lock_parent(lower_dentry);
	rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
	if (rc || !lower_dentry->d_inode)
		goto out;
	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
	if (rc)
		goto out;
	fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
out:
	unlock_dir(lower_dir_dentry);
	if (!dentry->d_inode)
		d_drop(dentry);
	return rc;
}

static int
ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
		struct inode *new_dir, struct dentry *new_dentry)
{
	int rc;
	struct dentry *lower_old_dentry;
	struct dentry *lower_new_dentry;
	struct dentry *lower_old_dir_dentry;
	struct dentry *lower_new_dir_dentry;

	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
	dget(lower_old_dentry);
	dget(lower_new_dentry);
	lower_old_dir_dentry = dget_parent(lower_old_dentry);
	lower_new_dir_dentry = dget_parent(lower_new_dentry);
	lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
	rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
			lower_new_dir_dentry->d_inode, lower_new_dentry);
	if (rc)
		goto out_lock;
	fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode, NULL);
	if (new_dir != old_dir)
		fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode, NULL);
out_lock:
	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
	dput(lower_new_dentry->d_parent);
	dput(lower_old_dentry->d_parent);
	dput(lower_new_dentry);
	dput(lower_old_dentry);
	return rc;
}

static int
ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
{
	int rc;
	struct dentry *lower_dentry;
	char *decoded_name;
	char *lower_buf;
	mm_segment_t old_fs;
	struct ecryptfs_crypt_stat *crypt_stat;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	if (!lower_dentry->d_inode->i_op ||
	    !lower_dentry->d_inode->i_op->readlink) {
		rc = -EINVAL;
		goto out;
	}
	/* Released in this function */
	lower_buf = kmalloc(bufsiz, GFP_KERNEL);
	if (lower_buf == NULL) {
		ecryptfs_printk(KERN_ERR, "Out of memory\n");
		rc = -ENOMEM;
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
			"lower_dentry->d_name.name = [%s]\n",
			lower_dentry->d_name.name);
	rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
						   (char __user *)lower_buf,
						   bufsiz);
	set_fs(old_fs);
	if (rc >= 0) {
		crypt_stat = NULL;
		rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
					      &decoded_name);
		if (rc == -ENOMEM)
			goto out_free_lower_buf;
		if (rc > 0) {
			ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
					"to userspace: [%*s]\n", rc,
					decoded_name);
			if (copy_to_user(buf, decoded_name, rc))
				rc = -EFAULT;
		}
		kfree(decoded_name);
		fsstack_copy_attr_atime(dentry->d_inode,
					lower_dentry->d_inode);
	}
out_free_lower_buf:
	kfree(lower_buf);
out:
	return rc;
}

static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	char *buf;
	int len = PAGE_SIZE, rc;
	mm_segment_t old_fs;

	/* Released in ecryptfs_put_link(); only release here on error */
	buf = kmalloc(len, GFP_KERNEL);
	if (!buf) {
		rc = -ENOMEM;
		goto out;
	}
	old_fs = get_fs();
	set_fs(get_ds());
	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
			"dentry->d_name.name = [%s]\n", dentry->d_name.name);
	rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
	buf[rc] = '\0';
	set_fs(old_fs);
	if (rc < 0)
		goto out_free;
	rc = 0;
	nd_set_link(nd, buf);
	goto out;
out_free:
	kfree(buf);
out:
	return ERR_PTR(rc);
}

static void
ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
{
	/* Free the char* */
	kfree(nd_get_link(nd));
}

/**
 * upper_size_to_lower_size
 * @crypt_stat: Crypt_stat associated with file
 * @upper_size: Size of the upper file
 *
 * Calculate the requried size of the lower file based on the
 * specified size of the upper file. This calculation is based on the
 * number of headers in the underlying file and the extent size.
 *
 * Returns Calculated size of the lower file.
 */
static loff_t
upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
			 loff_t upper_size)
{
	loff_t lower_size;

	lower_size = (crypt_stat->extent_size
		      * crypt_stat->num_header_extents_at_front);
	if (upper_size != 0) {