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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */2#ifndef _LINUX_CACHEFILES_H3#define _LINUX_CACHEFILES_H4 5#include <linux/types.h>6#include <linux/ioctl.h>7 8/*9 * Fscache ensures that the maximum length of cookie key is 255. The volume key10 * is controlled by netfs, and generally no bigger than 255.11 */12#define CACHEFILES_MSG_MAX_SIZE 102413 14enum cachefiles_opcode {15 CACHEFILES_OP_OPEN,16 CACHEFILES_OP_CLOSE,17 CACHEFILES_OP_READ,18};19 20/*21 * Message Header22 *23 * @msg_id a unique ID identifying this message24 * @opcode message type, CACHEFILE_OP_*25 * @len message length, including message header and following data26 * @object_id a unique ID identifying a cache file27 * @data message type specific payload28 */29struct cachefiles_msg {30 __u32 msg_id;31 __u32 opcode;32 __u32 len;33 __u32 object_id;34 __u8 data[];35};36 37/*38 * @data contains the volume_key followed directly by the cookie_key. volume_key39 * is a NUL-terminated string; @volume_key_size indicates the size of the volume40 * key in bytes. cookie_key is binary data, which is netfs specific;41 * @cookie_key_size indicates the size of the cookie key in bytes.42 *43 * @fd identifies an anon_fd referring to the cache file.44 */45struct cachefiles_open {46 __u32 volume_key_size;47 __u32 cookie_key_size;48 __u32 fd;49 __u32 flags;50 __u8 data[];51};52 53/*54 * @off indicates the starting offset of the requested file range55 * @len indicates the length of the requested file range56 */57struct cachefiles_read {58 __u64 off;59 __u64 len;60};61 62/*63 * Reply for READ request64 * @arg for this ioctl is the @id field of READ request.65 */66#define CACHEFILES_IOC_READ_COMPLETE _IOW(0x98, 1, int)67 68#endif69