xref: /openbmc/linux/fs/afs/xdr_fs.h (revision 6417f031)
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  
11  struct 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   */
50  union 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   */
74  struct 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   */
86  union 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   */
101  struct 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   */
110  static 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