fsmap.h (4394B)
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 */ 50struct 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 60struct 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. */ 72static inline __kernel_size_t 73fsmap_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. */ 80static inline void 81fsmap_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 */