Google
Edit File: fsmap.h
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ /* * FS_IOC_GETFSMAP ioctl infrastructure. * * Copyright (C) 2017 Oracle. All Rights Reserved. * * Author: Darrick J. Wong <darrick.wong@oracle.com> */ #ifndef _LINUX_FSMAP_H #define _LINUX_FSMAP_H #include <linux/types.h> /* * Structure for FS_IOC_GETFSMAP. * * The memory layout for this call are the scalar values defined in * struct fsmap_head, followed by two struct fsmap that describe * the lower and upper bound of mappings to return, followed by an * array of struct fsmap mappings. * * fmh_iflags control the output of the call, whereas fmh_oflags report * on the overall record output. fmh_count should be set to the * length of the fmh_recs array, and fmh_entries will be set to the * number of entries filled out during each call. If fmh_count is * zero, the number of reverse mappings will be returned in * fmh_entries, though no mappings will be returned. fmh_reserved * must be set to zero. * * The two elements in the fmh_keys array are used to constrain the * output. The first element in the array should represent the * lowest disk mapping ("low key") that the user wants to learn * about. If this value is all zeroes, the filesystem will return * the first entry it knows about. For a subsequent call, the * contents of fsmap_head.fmh_recs[fsmap_head.fmh_count - 1] should be * copied into fmh_keys[0] to have the kernel start where it left off. * * The second element in the fmh_keys array should represent the * highest disk mapping ("high key") that the user wants to learn * about. If this value is all ones, the filesystem will not stop * until it runs out of mapping to return or runs out of space in * fmh_recs. * * fmr_device can be either a 32-bit cookie representing a device, or * a 32-bit dev_t if the FMH_OF_DEV_T flag is set. fmr_physical, * fmr_offset, and fmr_length are expressed in units of bytes. * fmr_owner is either an inode number, or a special value if * FMR_OF_SPECIAL_OWNER is set in fmr_flags. */ struct fsmap { __u32 fmr_device; /* device id */ __u32 fmr_flags; /* mapping flags */ __u64 fmr_physical; /* device offset of segment */ __u64 fmr_owner; /* owner id */ __u64 fmr_offset; /* file offset of segment */ __u64 fmr_length; /* length of segment */ __u64 fmr_reserved[3]; /* must be zero */ }; struct fsmap_head { __u32 fmh_iflags; /* control flags */ __u32 fmh_oflags; /* output flags */ __u32 fmh_count; /* # of entries in array incl. input */ __u32 fmh_entries; /* # of entries filled in (output). */ __u64 fmh_reserved[6]; /* must be zero */ struct fsmap fmh_keys[2]; /* low and high keys for the mapping search */ struct fsmap fmh_recs[]; /* returned records */ }; /* Size of an fsmap_head with room for nr records. */ static __inline__ size_t fsmap_sizeof( unsigned int nr) { return sizeof(struct fsmap_head) + nr * sizeof(struct fsmap); } /* Start the next fsmap query at the end of the current query results. */ static __inline__ void fsmap_advance( struct fsmap_head *head) { head->fmh_keys[0] = head->fmh_recs[head->fmh_entries - 1]; } /* fmh_iflags values - set by FS_IOC_GETFSMAP caller in the header. */ /* no flags defined yet */ #define FMH_IF_VALID 0 /* fmh_oflags values - returned in the header segment only. */ #define FMH_OF_DEV_T 0x1 /* fmr_device values will be dev_t */ /* fmr_flags values - returned for each non-header segment */ #define FMR_OF_PREALLOC 0x1 /* segment = unwritten pre-allocation */ #define FMR_OF_ATTR_FORK 0x2 /* segment = attribute fork */ #define FMR_OF_EXTENT_MAP 0x4 /* segment = extent map */ #define FMR_OF_SHARED 0x8 /* segment = shared with another file */ #define FMR_OF_SPECIAL_OWNER 0x10 /* owner is a special value */ #define FMR_OF_LAST 0x20 /* segment is the last in the dataset */ /* Each FS gets to define its own special owner codes. */ #define FMR_OWNER(type, code) (((__u64)type << 32) | \ ((__u64)code & 0xFFFFFFFFULL)) #define FMR_OWNER_TYPE(owner) ((__u32)((__u64)owner >> 32)) #define FMR_OWNER_CODE(owner) ((__u32)(((__u64)owner & 0xFFFFFFFFULL))) #define FMR_OWN_FREE FMR_OWNER(0, 1) /* free space */ #define FMR_OWN_UNKNOWN FMR_OWNER(0, 2) /* unknown owner */ #define FMR_OWN_METADATA FMR_OWNER(0, 3) /* metadata */ #define FS_IOC_GETFSMAP _IOWR('X', 59, struct fsmap_head) #endif /* _LINUX_FSMAP_H */