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/*
* 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 FS */
/* 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 */
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