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1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef LINUX_IOMAP_H
3 #define LINUX_IOMAP_H 1
4 
5 #include <linux/types.h>
6 
7 struct fiemap_extent_info;
8 struct inode;
9 struct iov_iter;
10 struct kiocb;
11 struct vm_area_struct;
12 struct vm_fault;
13 
14 /*
15  * Types of block ranges for iomap mappings:
16  */
17 #define IOMAP_HOLE	0x01	/* no blocks allocated, need allocation */
18 #define IOMAP_DELALLOC	0x02	/* delayed allocation blocks */
19 #define IOMAP_MAPPED	0x03	/* blocks allocated @blkno */
20 #define IOMAP_UNWRITTEN	0x04	/* blocks allocated @blkno in unwritten state */
21 
22 /*
23  * Flags for all iomap mappings:
24  */
25 #define IOMAP_F_NEW	0x01	/* blocks have been newly allocated */
26 
27 /*
28  * Flags that only need to be reported for IOMAP_REPORT requests:
29  */
30 #define IOMAP_F_MERGED	0x10	/* contains multiple blocks/extents */
31 #define IOMAP_F_SHARED	0x20	/* block shared with another file */
32 
33 /*
34  * Magic value for blkno:
35  */
36 #define IOMAP_NULL_BLOCK -1LL	/* blkno is not valid */
37 
38 struct iomap {
39 	sector_t		blkno;	/* 1st sector of mapping, 512b units */
40 	loff_t			offset;	/* file offset of mapping, bytes */
41 	u64			length;	/* length of mapping, bytes */
42 	u16			type;	/* type of mapping */
43 	u16			flags;	/* flags for mapping */
44 	struct block_device	*bdev;	/* block device for I/O */
45 	struct dax_device	*dax_dev; /* dax_dev for dax operations */
46 };
47 
48 /*
49  * Flags for iomap_begin / iomap_end.  No flag implies a read.
50  */
51 #define IOMAP_WRITE		(1 << 0) /* writing, must allocate blocks */
52 #define IOMAP_ZERO		(1 << 1) /* zeroing operation, may skip holes */
53 #define IOMAP_REPORT		(1 << 2) /* report extent status, e.g. FIEMAP */
54 #define IOMAP_FAULT		(1 << 3) /* mapping for page fault */
55 #define IOMAP_DIRECT		(1 << 4) /* direct I/O */
56 #define IOMAP_NOWAIT		(1 << 5) /* Don't wait for writeback */
57 
58 struct iomap_ops {
59 	/*
60 	 * Return the existing mapping at pos, or reserve space starting at
61 	 * pos for up to length, as long as we can do it as a single mapping.
62 	 * The actual length is returned in iomap->length.
63 	 */
64 	int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
65 			unsigned flags, struct iomap *iomap);
66 
67 	/*
68 	 * Commit and/or unreserve space previous allocated using iomap_begin.
69 	 * Written indicates the length of the successful write operation which
70 	 * needs to be commited, while the rest needs to be unreserved.
71 	 * Written might be zero if no data was written.
72 	 */
73 	int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
74 			ssize_t written, unsigned flags, struct iomap *iomap);
75 };
76 
77 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
78 		const struct iomap_ops *ops);
79 int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
80 		const struct iomap_ops *ops);
81 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
82 		bool *did_zero, const struct iomap_ops *ops);
83 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
84 		const struct iomap_ops *ops);
85 int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops);
86 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
87 		loff_t start, loff_t len, const struct iomap_ops *ops);
88 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
89 		const struct iomap_ops *ops);
90 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
91 		const struct iomap_ops *ops);
92 
93 /*
94  * Flags for direct I/O ->end_io:
95  */
96 #define IOMAP_DIO_UNWRITTEN	(1 << 0)	/* covers unwritten extent(s) */
97 #define IOMAP_DIO_COW		(1 << 1)	/* covers COW extent(s) */
98 typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
99 		unsigned flags);
100 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
101 		const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
102 
103 #endif /* LINUX_IOMAP_H */
104