Linux kernel mirror (for testing)
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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 iomap mappings:
23 */
24#define IOMAP_F_MERGED 0x01 /* contains multiple blocks/extents */
25
26/*
27 * Magic value for blkno:
28 */
29#define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */
30
31struct iomap {
32 sector_t blkno; /* 1st sector of mapping, 512b units */
33 loff_t offset; /* file offset of mapping, bytes */
34 u64 length; /* length of mapping, bytes */
35 u16 type; /* type of mapping */
36 u16 flags; /* flags for mapping */
37 struct block_device *bdev; /* block device for I/O */
38};
39
40/*
41 * Flags for iomap_begin / iomap_end. No flag implies a read.
42 */
43#define IOMAP_WRITE (1 << 0)
44#define IOMAP_ZERO (1 << 1)
45
46struct iomap_ops {
47 /*
48 * Return the existing mapping at pos, or reserve space starting at
49 * pos for up to length, as long as we can do it as a single mapping.
50 * The actual length is returned in iomap->length.
51 */
52 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
53 unsigned flags, struct iomap *iomap);
54
55 /*
56 * Commit and/or unreserve space previous allocated using iomap_begin.
57 * Written indicates the length of the successful write operation which
58 * needs to be commited, while the rest needs to be unreserved.
59 * Written might be zero if no data was written.
60 */
61 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
62 ssize_t written, unsigned flags, struct iomap *iomap);
63};
64
65ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
66 struct iomap_ops *ops);
67int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
68 bool *did_zero, struct iomap_ops *ops);
69int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
70 struct iomap_ops *ops);
71int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
72 struct iomap_ops *ops);
73int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
74 loff_t start, loff_t len, struct iomap_ops *ops);
75
76#endif /* LINUX_IOMAP_H */