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