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113 lines
4.3 KiB
113 lines
4.3 KiB
/* 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 <[email protected]> |
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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 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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