include/uapi/linux/fsmap.h

Source file repositories/reference/linux-study-clean/include/uapi/linux/fsmap.h

File Facts

System
Linux kernel
Corpus path
include/uapi/linux/fsmap.h
Extension
.h
Size
4394 bytes
Lines
114
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

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 __kernel_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 */

Annotation

Implementation Notes