diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/uapi/linux/fsmap.h | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/include/uapi/linux/fsmap.h b/include/uapi/linux/fsmap.h new file mode 100644 index 000000000000..7e8e5f0bd6d2 --- /dev/null +++ b/include/uapi/linux/fsmap.h @@ -0,0 +1,112 @@ +/* + * 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 */ |