Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 struct dax_device *dax_dev; /* dax_dev for dax operations */
45};
46
47/*
48 * Flags for iomap_begin / iomap_end. No flag implies a read.
49 */
50#define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
51#define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
52#define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
53#define IOMAP_FAULT (1 << 3) /* mapping for page fault */
54#define IOMAP_DIRECT (1 << 4) /* direct I/O */
55#define IOMAP_NOWAIT (1 << 5) /* Don't wait for writeback */
56
57struct iomap_ops {
58 /*
59 * Return the existing mapping at pos, or reserve space starting at
60 * pos for up to length, as long as we can do it as a single mapping.
61 * The actual length is returned in iomap->length.
62 */
63 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
64 unsigned flags, struct iomap *iomap);
65
66 /*
67 * Commit and/or unreserve space previous allocated using iomap_begin.
68 * Written indicates the length of the successful write operation which
69 * needs to be commited, while the rest needs to be unreserved.
70 * Written might be zero if no data was written.
71 */
72 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
73 ssize_t written, unsigned flags, struct iomap *iomap);
74};
75
76ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
77 const struct iomap_ops *ops);
78int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
79 const struct iomap_ops *ops);
80int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
81 bool *did_zero, const struct iomap_ops *ops);
82int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
83 const struct iomap_ops *ops);
84int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops);
85int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
86 loff_t start, loff_t len, const struct iomap_ops *ops);
87loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
88 const struct iomap_ops *ops);
89loff_t iomap_seek_data(struct inode *inode, loff_t offset,
90 const struct iomap_ops *ops);
91
92/*
93 * Flags for direct I/O ->end_io:
94 */
95#define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
96#define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
97typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
98 unsigned flags);
99ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
100 const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
101
102#endif /* LINUX_IOMAP_H */