1#ifndef LINUX_IOMAP_H
 2#define LINUX_IOMAP_H 1
 3
 4#include <linux/types.h>
 5
 6struct fiemap_extent_info;
 7struct inode;
 8struct iov_iter;
 9struct kiocb;
10struct vm_area_struct;
11struct vm_fault;
12
13/*
14 * Types of block ranges for iomap mappings:
15 */
16#define IOMAP_HOLE	0x01	/* no blocks allocated, need allocation */
17#define IOMAP_DELALLOC	0x02	/* delayed allocation blocks */
18#define IOMAP_MAPPED	0x03	/* blocks allocated @blkno */
19#define IOMAP_UNWRITTEN	0x04	/* blocks allocated @blkno in unwritten state */
20
21/*
22 * Flags for all iomap mappings:
23 */
24#define IOMAP_F_NEW	0x01	/* blocks have been newly allocated */
25
26/*
27 * Flags that only need to be reported for IOMAP_REPORT requests:
28 */
29#define IOMAP_F_MERGED	0x10	/* contains multiple blocks/extents */
30#define IOMAP_F_SHARED	0x20	/* block shared with another file */
31
32/*
33 * Magic value for blkno:
34 */
35#define IOMAP_NULL_BLOCK -1LL	/* blkno is not valid */
36
37struct iomap {
38	sector_t		blkno;	/* 1st sector of mapping, 512b units */
39	loff_t			offset;	/* file offset of mapping, bytes */
40	u64			length;	/* length of mapping, bytes */
41	u16			type;	/* type of mapping */
42	u16			flags;	/* flags for mapping */
43	struct block_device	*bdev;	/* block device for I/O */
44};
45
46/*
47 * Flags for iomap_begin / iomap_end.  No flag implies a read.
48 */
49#define IOMAP_WRITE		(1 << 0) /* writing, must allocate blocks */
50#define IOMAP_ZERO		(1 << 1) /* zeroing operation, may skip holes */
51#define IOMAP_REPORT		(1 << 2) /* report extent status, e.g. FIEMAP */
52#define IOMAP_FAULT		(1 << 3) /* mapping for page fault */
53#define IOMAP_DIRECT		(1 << 4) /* direct I/O */
54
55struct iomap_ops {
56	/*
57	 * Return the existing mapping at pos, or reserve space starting at
58	 * pos for up to length, as long as we can do it as a single mapping.
59	 * The actual length is returned in iomap->length.
60	 */
61	int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
62			unsigned flags, struct iomap *iomap);
63
64	/*
65	 * Commit and/or unreserve space previous allocated using iomap_begin.
66	 * Written indicates the length of the successful write operation which
67	 * needs to be commited, while the rest needs to be unreserved.
68	 * Written might be zero if no data was written.
69	 */
70	int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
71			ssize_t written, unsigned flags, struct iomap *iomap);
72};
73
74ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
75		struct iomap_ops *ops);
76int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
77		struct iomap_ops *ops);
78int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
79		bool *did_zero, struct iomap_ops *ops);
80int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
81		struct iomap_ops *ops);
82int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
83		struct iomap_ops *ops);
84int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
85		loff_t start, loff_t len, struct iomap_ops *ops);
86
87/*
88 * Flags for direct I/O ->end_io:
89 */
90#define IOMAP_DIO_UNWRITTEN	(1 << 0)	/* covers unwritten extent(s) */
91#define IOMAP_DIO_COW		(1 << 1)	/* covers COW extent(s) */
92typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
93		unsigned flags);
94ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
95		struct iomap_ops *ops, iomap_dio_end_io_t end_io);
96
97#endif /* LINUX_IOMAP_H */