1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 #ifndef _LINUX_CACHEFILES_H 3 #define _LINUX_CACHEFILES_H 4 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 key 10 * is controlled by netfs, and generally no bigger than 255. 11 */ 12 #define CACHEFILES_MSG_MAX_SIZE 1024 13 14 enum cachefiles_opcode { 15 CACHEFILES_OP_OPEN, 16 CACHEFILES_OP_CLOSE, 17 CACHEFILES_OP_READ, 18 }; 19 20 /* 21 * Message Header 22 * 23 * @msg_id a unique ID identifying this message 24 * @opcode message type, CACHEFILE_OP_* 25 * @len message length, including message header and following data 26 * @object_id a unique ID identifying a cache file 27 * @data message type specific payload 28 */ 29 struct 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_key 39 * is a NUL-terminated string; @volume_key_size indicates the size of the volume 40 * 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 */ 45 struct 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 range 55 * @len indicates the length of the requested file range 56 */ 57 struct cachefiles_read { 58 __u64 off; 59 __u64 len; 60 }; 61 62 /* 63 * Reply for READ request 64 * @arg for this ioctl is the @id field of READ request. 65 */ 66 #define CACHEFILES_IOC_READ_COMPLETE _IOW(0x98, 1, int) 67 68 #endif 69