1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
2 | /* |
3 | * FS_IOC_GETFSMAP ioctl infrastructure. |
4 | * |
5 | * Copyright (C) 2017 Oracle. All Rights Reserved. |
6 | * |
7 | * Author: Darrick J. Wong <darrick.wong@oracle.com> |
8 | */ |
9 | #ifndef _LINUX_FSMAP_H |
10 | #define _LINUX_FSMAP_H |
11 | |
12 | #include <linux/types.h> |
13 | |
14 | /* |
15 | * Structure for FS_IOC_GETFSMAP. |
16 | * |
17 | * The memory layout for this call are the scalar values defined in |
18 | * struct fsmap_head, followed by two struct fsmap that describe |
19 | * the lower and upper bound of mappings to return, followed by an |
20 | * array of struct fsmap mappings. |
21 | * |
22 | * fmh_iflags control the output of the call, whereas fmh_oflags report |
23 | * on the overall record output. fmh_count should be set to the |
24 | * length of the fmh_recs array, and fmh_entries will be set to the |
25 | * number of entries filled out during each call. If fmh_count is |
26 | * zero, the number of reverse mappings will be returned in |
27 | * fmh_entries, though no mappings will be returned. fmh_reserved |
28 | * must be set to zero. |
29 | * |
30 | * The two elements in the fmh_keys array are used to constrain the |
31 | * output. The first element in the array should represent the |
32 | * lowest disk mapping ("low key") that the user wants to learn |
33 | * about. If this value is all zeroes, the filesystem will return |
34 | * the first entry it knows about. For a subsequent call, the |
35 | * contents of fsmap_head.fmh_recs[fsmap_head.fmh_count - 1] should be |
36 | * copied into fmh_keys[0] to have the kernel start where it left off. |
37 | * |
38 | * The second element in the fmh_keys array should represent the |
39 | * highest disk mapping ("high key") that the user wants to learn |
40 | * about. If this value is all ones, the filesystem will not stop |
41 | * until it runs out of mapping to return or runs out of space in |
42 | * fmh_recs. |
43 | * |
44 | * fmr_device can be either a 32-bit cookie representing a device, or |
45 | * a 32-bit dev_t if the FMH_OF_DEV_T flag is set. fmr_physical, |
46 | * fmr_offset, and fmr_length are expressed in units of bytes. |
47 | * fmr_owner is either an inode number, or a special value if |
48 | * FMR_OF_SPECIAL_OWNER is set in fmr_flags. |
49 | */ |
50 | struct fsmap { |
51 | __u32 fmr_device; /* device id */ |
52 | __u32 fmr_flags; /* mapping flags */ |
53 | __u64 fmr_physical; /* device offset of segment */ |
54 | __u64 fmr_owner; /* owner id */ |
55 | __u64 fmr_offset; /* file offset of segment */ |
56 | __u64 fmr_length; /* length of segment */ |
57 | __u64 fmr_reserved[3]; /* must be zero */ |
58 | }; |
59 | |
60 | struct fsmap_head { |
61 | __u32 fmh_iflags; /* control flags */ |
62 | __u32 fmh_oflags; /* output flags */ |
63 | __u32 fmh_count; /* # of entries in array incl. input */ |
64 | __u32 fmh_entries; /* # of entries filled in (output). */ |
65 | __u64 fmh_reserved[6]; /* must be zero */ |
66 | |
67 | struct fsmap fmh_keys[2]; /* low and high keys for the mapping search */ |
68 | struct fsmap fmh_recs[]; /* returned records */ |
69 | }; |
70 | |
71 | /* Size of an fsmap_head with room for nr records. */ |
72 | static inline __kernel_size_t |
73 | fsmap_sizeof( |
74 | unsigned int nr) |
75 | { |
76 | return sizeof(struct fsmap_head) + nr * sizeof(struct fsmap); |
77 | } |
78 | |
79 | /* Start the next fsmap query at the end of the current query results. */ |
80 | static inline void |
81 | fsmap_advance( |
82 | struct fsmap_head *head) |
83 | { |
84 | head->fmh_keys[0] = head->fmh_recs[head->fmh_entries - 1]; |
85 | } |
86 | |
87 | /* fmh_iflags values - set by FS_IOC_GETFSMAP caller in the header. */ |
88 | /* no flags defined yet */ |
89 | #define FMH_IF_VALID 0 |
90 | |
91 | /* fmh_oflags values - returned in the header segment only. */ |
92 | #define FMH_OF_DEV_T 0x1 /* fmr_device values will be dev_t */ |
93 | |
94 | /* fmr_flags values - returned for each non-header segment */ |
95 | #define FMR_OF_PREALLOC 0x1 /* segment = unwritten pre-allocation */ |
96 | #define FMR_OF_ATTR_FORK 0x2 /* segment = attribute fork */ |
97 | #define FMR_OF_EXTENT_MAP 0x4 /* segment = extent map */ |
98 | #define FMR_OF_SHARED 0x8 /* segment = shared with another file */ |
99 | #define FMR_OF_SPECIAL_OWNER 0x10 /* owner is a special value */ |
100 | #define FMR_OF_LAST 0x20 /* segment is the last in the dataset */ |
101 | |
102 | /* Each FS gets to define its own special owner codes. */ |
103 | #define FMR_OWNER(type, code) (((__u64)type << 32) | \ |
104 | ((__u64)code & 0xFFFFFFFFULL)) |
105 | #define FMR_OWNER_TYPE(owner) ((__u32)((__u64)owner >> 32)) |
106 | #define FMR_OWNER_CODE(owner) ((__u32)(((__u64)owner & 0xFFFFFFFFULL))) |
107 | #define FMR_OWN_FREE FMR_OWNER(0, 1) /* free space */ |
108 | #define FMR_OWN_UNKNOWN FMR_OWNER(0, 2) /* unknown owner */ |
109 | #define FMR_OWN_METADATA FMR_OWNER(0, 3) /* metadata */ |
110 | |
111 | #define FS_IOC_GETFSMAP _IOWR('X', 59, struct fsmap_head) |
112 | |
113 | #endif /* _LINUX_FSMAP_H */ |
114 | |