Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * FS_IOC_GETFSMAP ioctl infrastructure.
3 *
4 * Copyright (C) 2017 Oracle. All Rights Reserved.
5 *
6 * Author: Darrick J. Wong <darrick.wong@oracle.com>
7 */
8#ifndef _LINUX_FSMAP_H
9#define _LINUX_FSMAP_H
10
11#include <linux/types.h>
12
13/*
14 * Structure for FS_IOC_GETFSMAP.
15 *
16 * The memory layout for this call are the scalar values defined in
17 * struct fsmap_head, followed by two struct fsmap that describe
18 * the lower and upper bound of mappings to return, followed by an
19 * array of struct fsmap mappings.
20 *
21 * fmh_iflags control the output of the call, whereas fmh_oflags report
22 * on the overall record output. fmh_count should be set to the
23 * length of the fmh_recs array, and fmh_entries will be set to the
24 * number of entries filled out during each call. If fmh_count is
25 * zero, the number of reverse mappings will be returned in
26 * fmh_entries, though no mappings will be returned. fmh_reserved
27 * must be set to zero.
28 *
29 * The two elements in the fmh_keys array are used to constrain the
30 * output. The first element in the array should represent the
31 * lowest disk mapping ("low key") that the user wants to learn
32 * about. If this value is all zeroes, the filesystem will return
33 * the first entry it knows about. For a subsequent call, the
34 * contents of fsmap_head.fmh_recs[fsmap_head.fmh_count - 1] should be
35 * copied into fmh_keys[0] to have the kernel start where it left off.
36 *
37 * The second element in the fmh_keys array should represent the
38 * highest disk mapping ("high key") that the user wants to learn
39 * about. If this value is all ones, the filesystem will not stop
40 * until it runs out of mapping to return or runs out of space in
41 * fmh_recs.
42 *
43 * fmr_device can be either a 32-bit cookie representing a device, or
44 * a 32-bit dev_t if the FMH_OF_DEV_T flag is set. fmr_physical,
45 * fmr_offset, and fmr_length are expressed in units of bytes.
46 * fmr_owner is either an inode number, or a special value if
47 * FMR_OF_SPECIAL_OWNER is set in fmr_flags.
48 */
49struct fsmap {
50 __u32 fmr_device; /* device id */
51 __u32 fmr_flags; /* mapping flags */
52 __u64 fmr_physical; /* device offset of segment */
53 __u64 fmr_owner; /* owner id */
54 __u64 fmr_offset; /* file offset of segment */
55 __u64 fmr_length; /* length of segment */
56 __u64 fmr_reserved[3]; /* must be zero */
57};
58
59struct fsmap_head {
60 __u32 fmh_iflags; /* control flags */
61 __u32 fmh_oflags; /* output flags */
62 __u32 fmh_count; /* # of entries in array incl. input */
63 __u32 fmh_entries; /* # of entries filled in (output). */
64 __u64 fmh_reserved[6]; /* must be zero */
65
66 struct fsmap fmh_keys[2]; /* low and high keys for the mapping search */
67 struct fsmap fmh_recs[]; /* returned records */
68};
69
70/* Size of an fsmap_head with room for nr records. */
71static inline size_t
72fsmap_sizeof(
73 unsigned int nr)
74{
75 return sizeof(struct fsmap_head) + nr * sizeof(struct fsmap);
76}
77
78/* Start the next fsmap query at the end of the current query results. */
79static inline void
80fsmap_advance(
81 struct fsmap_head *head)
82{
83 head->fmh_keys[0] = head->fmh_recs[head->fmh_entries - 1];
84}
85
86/* fmh_iflags values - set by FS_IOC_GETFSMAP caller in the header. */
87/* no flags defined yet */
88#define FMH_IF_VALID 0
89
90/* fmh_oflags values - returned in the header segment only. */
91#define FMH_OF_DEV_T 0x1 /* fmr_device values will be dev_t */
92
93/* fmr_flags values - returned for each non-header segment */
94#define FMR_OF_PREALLOC 0x1 /* segment = unwritten pre-allocation */
95#define FMR_OF_ATTR_FORK 0x2 /* segment = attribute fork */
96#define FMR_OF_EXTENT_MAP 0x4 /* segment = extent map */
97#define FMR_OF_SHARED 0x8 /* segment = shared with another file */
98#define FMR_OF_SPECIAL_OWNER 0x10 /* owner is a special value */
99#define FMR_OF_LAST 0x20 /* segment is the last in the FS */
100
101/* Each FS gets to define its own special owner codes. */
102#define FMR_OWNER(type, code) (((__u64)type << 32) | \
103 ((__u64)code & 0xFFFFFFFFULL))
104#define FMR_OWNER_TYPE(owner) ((__u32)((__u64)owner >> 32))
105#define FMR_OWNER_CODE(owner) ((__u32)(((__u64)owner & 0xFFFFFFFFULL)))
106#define FMR_OWN_FREE FMR_OWNER(0, 1) /* free space */
107#define FMR_OWN_UNKNOWN FMR_OWNER(0, 2) /* unknown owner */
108#define FMR_OWN_METADATA FMR_OWNER(0, 3) /* metadata */
109
110#define FS_IOC_GETFSMAP _IOWR('X', 59, struct fsmap_head)
111
112#endif /* _LINUX_FSMAP_H */