1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/* AFS fileserver XDR types
3 *
4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#ifndef XDR_FS_H
9#define XDR_FS_H
10
11struct afs_xdr_AFSFetchStatus {
12	__be32	if_version;
13#define AFS_FSTATUS_VERSION	1
14	__be32	type;
15	__be32	nlink;
16	__be32	size_lo;
17	__be32	data_version_lo;
18	__be32	author;
19	__be32	owner;
20	__be32	caller_access;
21	__be32	anon_access;
22	__be32	mode;
23	__be32	parent_vnode;
24	__be32	parent_unique;
25	__be32	seg_size;
26	__be32	mtime_client;
27	__be32	mtime_server;
28	__be32	group;
29	__be32	sync_counter;
30	__be32	data_version_hi;
31	__be32	lock_count;
32	__be32	size_hi;
33	__be32	abort_code;
34} __packed;
35
36#define AFS_DIR_HASHTBL_SIZE	128
37#define AFS_DIR_DIRENT_SIZE	32
38#define AFS_DIR_SLOTS_PER_BLOCK	64
39#define AFS_DIR_BLOCK_SIZE	2048
40#define AFS_DIR_BLOCKS_PER_PAGE	(PAGE_SIZE / AFS_DIR_BLOCK_SIZE)
41#define AFS_DIR_MAX_SLOTS	65536
42#define AFS_DIR_BLOCKS_WITH_CTR	128
43#define AFS_DIR_MAX_BLOCKS	1023
44#define AFS_DIR_RESV_BLOCKS	1
45#define AFS_DIR_RESV_BLOCKS0	13
46
47/*
48 * Directory entry structure.
49 */
50union afs_xdr_dirent {
51	struct {
52		u8		valid;
53		u8		unused[1];
54		__be16		hash_next;
55		__be32		vnode;
56		__be32		unique;
57		u8		name[];
58		/* When determining the number of dirent slots needed to
59		 * represent a directory entry, name should be assumed to be 16
60		 * bytes, due to a now-standardised (mis)calculation, but it is
61		 * in fact 20 bytes in size.  afs_dir_calc_slots() should be
62		 * used for this.
63		 *
64		 * For names longer than (16 or) 20 bytes, extra slots should
65		 * be annexed to this one using the extended_name format.
66		 */
67	} u;
68	u8			extended_name[32];
69} __packed;
70
71/*
72 * Directory block header (one at the beginning of every 2048-byte block).
73 */
74struct afs_xdr_dir_hdr {
75	__be16		npages;
76	__be16		magic;
77#define AFS_DIR_MAGIC htons(1234)
78	u8		reserved;
79	u8		bitmap[8];
80	u8		pad[19];
81} __packed;
82
83/*
84 * Directory block layout
85 */
86union afs_xdr_dir_block {
87	struct afs_xdr_dir_hdr		hdr;
88
89	struct {
90		struct afs_xdr_dir_hdr	hdr;
91		u8			alloc_ctrs[AFS_DIR_MAX_BLOCKS];
92		__be16			hashtable[AFS_DIR_HASHTBL_SIZE];
93	} meta;
94
95	union afs_xdr_dirent	dirents[AFS_DIR_SLOTS_PER_BLOCK];
96} __packed;
97
98/*
99 * Directory layout on a linux VM page.
100 */
101struct afs_xdr_dir_page {
102	union afs_xdr_dir_block	blocks[AFS_DIR_BLOCKS_PER_PAGE];
103};
104
105/*
106 * Calculate the number of dirent slots required for any given name length.
107 * The calculation is made assuming the part of the name in the first slot is
108 * 16 bytes, rather than 20, but this miscalculation is now standardised.
109 */
110static inline unsigned int afs_dir_calc_slots(size_t name_len)
111{
112	name_len++; /* NUL-terminated */
113	return 1 + ((name_len + 15) / AFS_DIR_DIRENT_SIZE);
114}
115
116#endif /* XDR_FS_H */
117