1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef LINUX_IOMAP_H
3#define LINUX_IOMAP_H 1
4
5#include <linux/atomic.h>
6#include <linux/bitmap.h>
7#include <linux/mm.h>
8#include <linux/types.h>
9#include <linux/mm_types.h>
10
11struct address_space;
12struct fiemap_extent_info;
13struct inode;
14struct iov_iter;
15struct kiocb;
16struct page;
17struct vm_area_struct;
18struct vm_fault;
19
20/*
21 * Types of block ranges for iomap mappings:
22 */
23#define IOMAP_HOLE 0x01 /* no blocks allocated, need allocation */
24#define IOMAP_DELALLOC 0x02 /* delayed allocation blocks */
25#define IOMAP_MAPPED 0x03 /* blocks allocated at @addr */
26#define IOMAP_UNWRITTEN 0x04 /* blocks allocated at @addr in unwritten state */
27#define IOMAP_INLINE 0x05 /* data inline in the inode */
28
29/*
30 * Flags for all iomap mappings:
31 *
32 * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
33 * written data and requires fdatasync to commit them to persistent storage.
34 */
35#define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */
36#define IOMAP_F_DIRTY 0x02 /* uncommitted metadata */
37#define IOMAP_F_BUFFER_HEAD 0x04 /* file system requires buffer heads */
38
39/*
40 * Flags that only need to be reported for IOMAP_REPORT requests:
41 */
42#define IOMAP_F_MERGED 0x10 /* contains multiple blocks/extents */
43#define IOMAP_F_SHARED 0x20 /* block shared with another file */
44
45/*
46 * Flags from 0x1000 up are for file system specific usage:
47 */
48#define IOMAP_F_PRIVATE 0x1000
49
50
51/*
52 * Magic value for addr:
53 */
54#define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
55
56struct iomap {
57 u64 addr; /* disk offset of mapping, bytes */
58 loff_t offset; /* file offset of mapping, bytes */
59 u64 length; /* length of mapping, bytes */
60 u16 type; /* type of mapping */
61 u16 flags; /* flags for mapping */
62 struct block_device *bdev; /* block device for I/O */
63 struct dax_device *dax_dev; /* dax_dev for dax operations */
64 void *inline_data;
65 void *private; /* filesystem private */
66
67 /*
68 * Called when finished processing a page in the mapping returned in
69 * this iomap. At least for now this is only supported in the buffered
70 * write path.
71 */
72 void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
73 struct page *page, struct iomap *iomap);
74};
75
76/*
77 * Flags for iomap_begin / iomap_end. No flag implies a read.
78 */
79#define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
80#define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
81#define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
82#define IOMAP_FAULT (1 << 3) /* mapping for page fault */
83#define IOMAP_DIRECT (1 << 4) /* direct I/O */
84#define IOMAP_NOWAIT (1 << 5) /* do not block */
85
86struct iomap_ops {
87 /*
88 * Return the existing mapping at pos, or reserve space starting at
89 * pos for up to length, as long as we can do it as a single mapping.
90 * The actual length is returned in iomap->length.
91 */
92 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
93 unsigned flags, struct iomap *iomap);
94
95 /*
96 * Commit and/or unreserve space previous allocated using iomap_begin.
97 * Written indicates the length of the successful write operation which
98 * needs to be commited, while the rest needs to be unreserved.
99 * Written might be zero if no data was written.
100 */
101 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
102 ssize_t written, unsigned flags, struct iomap *iomap);
103};
104
105/*
106 * Structure allocate for each page when block size < PAGE_SIZE to track
107 * sub-page uptodate status and I/O completions.
108 */
109struct iomap_page {
110 atomic_t read_count;
111 atomic_t write_count;
112 DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
113};
114
115static inline struct iomap_page *to_iomap_page(struct page *page)
116{
117 if (page_has_private(page))
118 return (struct iomap_page *)page_private(page);
119 return NULL;
120}
121
122ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
123 const struct iomap_ops *ops);
124int iomap_readpage(struct page *page, const struct iomap_ops *ops);
125int iomap_readpages(struct address_space *mapping, struct list_head *pages,
126 unsigned nr_pages, const struct iomap_ops *ops);
127int iomap_set_page_dirty(struct page *page);
128int iomap_is_partially_uptodate(struct page *page, unsigned long from,
129 unsigned long count);
130int iomap_releasepage(struct page *page, gfp_t gfp_mask);
131void iomap_invalidatepage(struct page *page, unsigned int offset,
132 unsigned int len);
133#ifdef CONFIG_MIGRATION
134int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
135 struct page *page, enum migrate_mode mode);
136#else
137#define iomap_migrate_page NULL
138#endif
139int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
140 const struct iomap_ops *ops);
141int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
142 bool *did_zero, const struct iomap_ops *ops);
143int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
144 const struct iomap_ops *ops);
145vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
146 const struct iomap_ops *ops);
147int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
148 loff_t start, loff_t len, const struct iomap_ops *ops);
149loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
150 const struct iomap_ops *ops);
151loff_t iomap_seek_data(struct inode *inode, loff_t offset,
152 const struct iomap_ops *ops);
153sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
154 const struct iomap_ops *ops);
155
156/*
157 * Flags for direct I/O ->end_io:
158 */
159#define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
160#define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
161typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
162 unsigned flags);
163ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
164 const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
165int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
166
167#ifdef CONFIG_SWAP
168struct file;
169struct swap_info_struct;
170
171int iomap_swapfile_activate(struct swap_info_struct *sis,
172 struct file *swap_file, sector_t *pagespan,
173 const struct iomap_ops *ops);
174#else
175# define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
176#endif /* CONFIG_SWAP */
177
178#endif /* LINUX_IOMAP_H */
179