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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/atomic.h>
6 : : #include <linux/bitmap.h>
7 : : #include <linux/blk_types.h>
8 : : #include <linux/mm.h>
9 : : #include <linux/types.h>
10 : : #include <linux/mm_types.h>
11 : : #include <linux/blkdev.h>
12 : :
13 : : struct address_space;
14 : : struct fiemap_extent_info;
15 : : struct inode;
16 : : struct iomap_writepage_ctx;
17 : : struct iov_iter;
18 : : struct kiocb;
19 : : struct page;
20 : : struct vm_area_struct;
21 : : struct vm_fault;
22 : :
23 : : /*
24 : : * Types of block ranges for iomap mappings:
25 : : */
26 : : #define IOMAP_HOLE 0 /* no blocks allocated, need allocation */
27 : : #define IOMAP_DELALLOC 1 /* delayed allocation blocks */
28 : : #define IOMAP_MAPPED 2 /* blocks allocated at @addr */
29 : : #define IOMAP_UNWRITTEN 3 /* blocks allocated at @addr in unwritten state */
30 : : #define IOMAP_INLINE 4 /* data inline in the inode */
31 : :
32 : : /*
33 : : * Flags reported by the file system from iomap_begin:
34 : : *
35 : : * IOMAP_F_NEW indicates that the blocks have been newly allocated and need
36 : : * zeroing for areas that no data is copied to.
37 : : *
38 : : * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
39 : : * written data and requires fdatasync to commit them to persistent storage.
40 : : * This needs to take into account metadata changes that *may* be made at IO
41 : : * completion, such as file size updates from direct IO.
42 : : *
43 : : * IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
44 : : * unshared as part a write.
45 : : *
46 : : * IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
47 : : * mappings.
48 : : *
49 : : * IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
50 : : * buffer heads for this mapping.
51 : : */
52 : : #define IOMAP_F_NEW 0x01
53 : : #define IOMAP_F_DIRTY 0x02
54 : : #define IOMAP_F_SHARED 0x04
55 : : #define IOMAP_F_MERGED 0x08
56 : : #define IOMAP_F_BUFFER_HEAD 0x10
57 : :
58 : : /*
59 : : * Flags set by the core iomap code during operations:
60 : : *
61 : : * IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
62 : : * has changed as the result of this write operation.
63 : : */
64 : : #define IOMAP_F_SIZE_CHANGED 0x100
65 : :
66 : : /*
67 : : * Flags from 0x1000 up are for file system specific usage:
68 : : */
69 : : #define IOMAP_F_PRIVATE 0x1000
70 : :
71 : :
72 : : /*
73 : : * Magic value for addr:
74 : : */
75 : : #define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
76 : :
77 : : struct iomap_page_ops;
78 : :
79 : : struct iomap {
80 : : u64 addr; /* disk offset of mapping, bytes */
81 : : loff_t offset; /* file offset of mapping, bytes */
82 : : u64 length; /* length of mapping, bytes */
83 : : u16 type; /* type of mapping */
84 : : u16 flags; /* flags for mapping */
85 : : struct block_device *bdev; /* block device for I/O */
86 : : struct dax_device *dax_dev; /* dax_dev for dax operations */
87 : : void *inline_data;
88 : : void *private; /* filesystem private */
89 : : const struct iomap_page_ops *page_ops;
90 : : };
91 : :
92 : : static inline sector_t
93 : 0 : iomap_sector(struct iomap *iomap, loff_t pos)
94 : : {
95 [ # # # # : 0 : return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
# # ]
96 : : }
97 : :
98 : : /*
99 : : * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
100 : : * and page_done will be called for each page written to. This only applies to
101 : : * buffered writes as unbuffered writes will not typically have pages
102 : : * associated with them.
103 : : *
104 : : * When page_prepare succeeds, page_done will always be called to do any
105 : : * cleanup work necessary. In that page_done call, @page will be NULL if the
106 : : * associated page could not be obtained.
107 : : */
108 : : struct iomap_page_ops {
109 : : int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
110 : : struct iomap *iomap);
111 : : void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
112 : : struct page *page, struct iomap *iomap);
113 : : };
114 : :
115 : : /*
116 : : * Flags for iomap_begin / iomap_end. No flag implies a read.
117 : : */
118 : : #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
119 : : #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
120 : : #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
121 : : #define IOMAP_FAULT (1 << 3) /* mapping for page fault */
122 : : #define IOMAP_DIRECT (1 << 4) /* direct I/O */
123 : : #define IOMAP_NOWAIT (1 << 5) /* do not block */
124 : :
125 : : struct iomap_ops {
126 : : /*
127 : : * Return the existing mapping at pos, or reserve space starting at
128 : : * pos for up to length, as long as we can do it as a single mapping.
129 : : * The actual length is returned in iomap->length.
130 : : */
131 : : int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
132 : : unsigned flags, struct iomap *iomap,
133 : : struct iomap *srcmap);
134 : :
135 : : /*
136 : : * Commit and/or unreserve space previous allocated using iomap_begin.
137 : : * Written indicates the length of the successful write operation which
138 : : * needs to be commited, while the rest needs to be unreserved.
139 : : * Written might be zero if no data was written.
140 : : */
141 : : int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
142 : : ssize_t written, unsigned flags, struct iomap *iomap);
143 : : };
144 : :
145 : : /*
146 : : * Main iomap iterator function.
147 : : */
148 : : typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
149 : : void *data, struct iomap *iomap, struct iomap *srcmap);
150 : :
151 : : loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
152 : : unsigned flags, const struct iomap_ops *ops, void *data,
153 : : iomap_actor_t actor);
154 : :
155 : : ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
156 : : const struct iomap_ops *ops);
157 : : int iomap_readpage(struct page *page, const struct iomap_ops *ops);
158 : : int iomap_readpages(struct address_space *mapping, struct list_head *pages,
159 : : unsigned nr_pages, const struct iomap_ops *ops);
160 : : int iomap_set_page_dirty(struct page *page);
161 : : int iomap_is_partially_uptodate(struct page *page, unsigned long from,
162 : : unsigned long count);
163 : : int iomap_releasepage(struct page *page, gfp_t gfp_mask);
164 : : void iomap_invalidatepage(struct page *page, unsigned int offset,
165 : : unsigned int len);
166 : : #ifdef CONFIG_MIGRATION
167 : : int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
168 : : struct page *page, enum migrate_mode mode);
169 : : #else
170 : : #define iomap_migrate_page NULL
171 : : #endif
172 : : int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
173 : : const struct iomap_ops *ops);
174 : : int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
175 : : bool *did_zero, const struct iomap_ops *ops);
176 : : int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
177 : : const struct iomap_ops *ops);
178 : : vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
179 : : const struct iomap_ops *ops);
180 : : int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
181 : : loff_t start, loff_t len, const struct iomap_ops *ops);
182 : : loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
183 : : const struct iomap_ops *ops);
184 : : loff_t iomap_seek_data(struct inode *inode, loff_t offset,
185 : : const struct iomap_ops *ops);
186 : : sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
187 : : const struct iomap_ops *ops);
188 : :
189 : : /*
190 : : * Structure for writeback I/O completions.
191 : : */
192 : : struct iomap_ioend {
193 : : struct list_head io_list; /* next ioend in chain */
194 : : u16 io_type;
195 : : u16 io_flags; /* IOMAP_F_* */
196 : : struct inode *io_inode; /* file being written to */
197 : : size_t io_size; /* size of the extent */
198 : : loff_t io_offset; /* offset in the file */
199 : : void *io_private; /* file system private data */
200 : : struct bio *io_bio; /* bio being built */
201 : : struct bio io_inline_bio; /* MUST BE LAST! */
202 : : };
203 : :
204 : : struct iomap_writeback_ops {
205 : : /*
206 : : * Required, maps the blocks so that writeback can be performed on
207 : : * the range starting at offset.
208 : : */
209 : : int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
210 : : loff_t offset);
211 : :
212 : : /*
213 : : * Optional, allows the file systems to perform actions just before
214 : : * submitting the bio and/or override the bio end_io handler for complex
215 : : * operations like copy on write extent manipulation or unwritten extent
216 : : * conversions.
217 : : */
218 : : int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
219 : :
220 : : /*
221 : : * Optional, allows the file system to discard state on a page where
222 : : * we failed to submit any I/O.
223 : : */
224 : : void (*discard_page)(struct page *page);
225 : : };
226 : :
227 : : struct iomap_writepage_ctx {
228 : : struct iomap iomap;
229 : : struct iomap_ioend *ioend;
230 : : const struct iomap_writeback_ops *ops;
231 : : };
232 : :
233 : : void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
234 : : void iomap_ioend_try_merge(struct iomap_ioend *ioend,
235 : : struct list_head *more_ioends,
236 : : void (*merge_private)(struct iomap_ioend *ioend,
237 : : struct iomap_ioend *next));
238 : : void iomap_sort_ioends(struct list_head *ioend_list);
239 : : int iomap_writepage(struct page *page, struct writeback_control *wbc,
240 : : struct iomap_writepage_ctx *wpc,
241 : : const struct iomap_writeback_ops *ops);
242 : : int iomap_writepages(struct address_space *mapping,
243 : : struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
244 : : const struct iomap_writeback_ops *ops);
245 : :
246 : : /*
247 : : * Flags for direct I/O ->end_io:
248 : : */
249 : : #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
250 : : #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
251 : :
252 : : struct iomap_dio_ops {
253 : : int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
254 : : unsigned flags);
255 : : };
256 : :
257 : : ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
258 : : const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
259 : : bool wait_for_completion);
260 : : int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
261 : :
262 : : #ifdef CONFIG_SWAP
263 : : struct file;
264 : : struct swap_info_struct;
265 : :
266 : : int iomap_swapfile_activate(struct swap_info_struct *sis,
267 : : struct file *swap_file, sector_t *pagespan,
268 : : const struct iomap_ops *ops);
269 : : #else
270 : : # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
271 : : #endif /* CONFIG_SWAP */
272 : :
273 : : #endif /* LINUX_IOMAP_H */
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