Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/fs/afs/xdr_fs.h
26282 views
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 ([email protected])

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_BLOCKS_WITH_CTR];

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


118