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