Line data Source code
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_dio;
17 : struct iomap_writepage_ctx;
18 : struct iov_iter;
19 : struct kiocb;
20 : struct page;
21 : struct vm_area_struct;
22 : struct vm_fault;
23 :
24 : /*
25 : * Types of block ranges for iomap mappings:
26 : */
27 : #define IOMAP_HOLE 0 /* no blocks allocated, need allocation */
28 : #define IOMAP_DELALLOC 1 /* delayed allocation blocks */
29 : #define IOMAP_MAPPED 2 /* blocks allocated at @addr */
30 : #define IOMAP_UNWRITTEN 3 /* blocks allocated at @addr in unwritten state */
31 : #define IOMAP_INLINE 4 /* data inline in the inode */
32 :
33 : /*
34 : * Flags reported by the file system from iomap_begin:
35 : *
36 : * IOMAP_F_NEW indicates that the blocks have been newly allocated and need
37 : * zeroing for areas that no data is copied to.
38 : *
39 : * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
40 : * written data and requires fdatasync to commit them to persistent storage.
41 : * This needs to take into account metadata changes that *may* be made at IO
42 : * completion, such as file size updates from direct IO.
43 : *
44 : * IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
45 : * unshared as part a write.
46 : *
47 : * IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
48 : * mappings.
49 : *
50 : * IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
51 : * buffer heads for this mapping.
52 : */
53 : #define IOMAP_F_NEW 0x01
54 : #define IOMAP_F_DIRTY 0x02
55 : #define IOMAP_F_SHARED 0x04
56 : #define IOMAP_F_MERGED 0x08
57 : #define IOMAP_F_BUFFER_HEAD 0x10
58 : #define IOMAP_F_ZONE_APPEND 0x20
59 :
60 : /*
61 : * Flags set by the core iomap code during operations:
62 : *
63 : * IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
64 : * has changed as the result of this write operation.
65 : */
66 : #define IOMAP_F_SIZE_CHANGED 0x100
67 :
68 : /*
69 : * Flags from 0x1000 up are for file system specific usage:
70 : */
71 : #define IOMAP_F_PRIVATE 0x1000
72 :
73 :
74 : /*
75 : * Magic value for addr:
76 : */
77 : #define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
78 :
79 : struct iomap_page_ops;
80 :
81 : struct iomap {
82 : u64 addr; /* disk offset of mapping, bytes */
83 : loff_t offset; /* file offset of mapping, bytes */
84 : u64 length; /* length of mapping, bytes */
85 : u16 type; /* type of mapping */
86 : u16 flags; /* flags for mapping */
87 : struct block_device *bdev; /* block device for I/O */
88 : struct dax_device *dax_dev; /* dax_dev for dax operations */
89 : void *inline_data;
90 : void *private; /* filesystem private */
91 : const struct iomap_page_ops *page_ops;
92 : };
93 :
94 : static inline sector_t
95 0 : iomap_sector(struct iomap *iomap, loff_t pos)
96 : {
97 0 : return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
98 : }
99 :
100 : /*
101 : * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
102 : * and page_done will be called for each page written to. This only applies to
103 : * buffered writes as unbuffered writes will not typically have pages
104 : * associated with them.
105 : *
106 : * When page_prepare succeeds, page_done will always be called to do any
107 : * cleanup work necessary. In that page_done call, @page will be NULL if the
108 : * associated page could not be obtained.
109 : */
110 : struct iomap_page_ops {
111 : int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
112 : struct iomap *iomap);
113 : void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
114 : struct page *page, struct iomap *iomap);
115 : };
116 :
117 : /*
118 : * Flags for iomap_begin / iomap_end. No flag implies a read.
119 : */
120 : #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
121 : #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
122 : #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
123 : #define IOMAP_FAULT (1 << 3) /* mapping for page fault */
124 : #define IOMAP_DIRECT (1 << 4) /* direct I/O */
125 : #define IOMAP_NOWAIT (1 << 5) /* do not block */
126 : #define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */
127 :
128 : struct iomap_ops {
129 : /*
130 : * Return the existing mapping at pos, or reserve space starting at
131 : * pos for up to length, as long as we can do it as a single mapping.
132 : * The actual length is returned in iomap->length.
133 : */
134 : int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
135 : unsigned flags, struct iomap *iomap,
136 : struct iomap *srcmap);
137 :
138 : /*
139 : * Commit and/or unreserve space previous allocated using iomap_begin.
140 : * Written indicates the length of the successful write operation which
141 : * needs to be commited, while the rest needs to be unreserved.
142 : * Written might be zero if no data was written.
143 : */
144 : int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
145 : ssize_t written, unsigned flags, struct iomap *iomap);
146 : };
147 :
148 : /*
149 : * Main iomap iterator function.
150 : */
151 : typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
152 : void *data, struct iomap *iomap, struct iomap *srcmap);
153 :
154 : loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
155 : unsigned flags, const struct iomap_ops *ops, void *data,
156 : iomap_actor_t actor);
157 :
158 : ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
159 : const struct iomap_ops *ops);
160 : int iomap_readpage(struct page *page, const struct iomap_ops *ops);
161 : void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
162 : int iomap_set_page_dirty(struct page *page);
163 : int iomap_is_partially_uptodate(struct page *page, unsigned long from,
164 : unsigned long count);
165 : int iomap_releasepage(struct page *page, gfp_t gfp_mask);
166 : void iomap_invalidatepage(struct page *page, unsigned int offset,
167 : unsigned int len);
168 : #ifdef CONFIG_MIGRATION
169 : int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
170 : struct page *page, enum migrate_mode mode);
171 : #else
172 : #define iomap_migrate_page NULL
173 : #endif
174 : int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
175 : const struct iomap_ops *ops);
176 : int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
177 : bool *did_zero, const struct iomap_ops *ops);
178 : int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
179 : const struct iomap_ops *ops);
180 : vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
181 : const struct iomap_ops *ops);
182 : int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
183 : u64 start, u64 len, const struct iomap_ops *ops);
184 : loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
185 : const struct iomap_ops *ops);
186 : loff_t iomap_seek_data(struct inode *inode, loff_t offset,
187 : const struct iomap_ops *ops);
188 : sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
189 : const struct iomap_ops *ops);
190 :
191 : /*
192 : * Structure for writeback I/O completions.
193 : */
194 : struct iomap_ioend {
195 : struct list_head io_list; /* next ioend in chain */
196 : u16 io_type;
197 : u16 io_flags; /* IOMAP_F_* */
198 : struct inode *io_inode; /* file being written to */
199 : size_t io_size; /* size of the extent */
200 : loff_t io_offset; /* offset in the file */
201 : void *io_private; /* file system private data */
202 : struct bio *io_bio; /* bio being built */
203 : struct bio io_inline_bio; /* MUST BE LAST! */
204 : };
205 :
206 : struct iomap_writeback_ops {
207 : /*
208 : * Required, maps the blocks so that writeback can be performed on
209 : * the range starting at offset.
210 : */
211 : int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
212 : loff_t offset);
213 :
214 : /*
215 : * Optional, allows the file systems to perform actions just before
216 : * submitting the bio and/or override the bio end_io handler for complex
217 : * operations like copy on write extent manipulation or unwritten extent
218 : * conversions.
219 : */
220 : int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
221 :
222 : /*
223 : * Optional, allows the file system to discard state on a page where
224 : * we failed to submit any I/O.
225 : */
226 : void (*discard_page)(struct page *page, loff_t fileoff);
227 : };
228 :
229 : struct iomap_writepage_ctx {
230 : struct iomap iomap;
231 : struct iomap_ioend *ioend;
232 : const struct iomap_writeback_ops *ops;
233 : };
234 :
235 : void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
236 : void iomap_ioend_try_merge(struct iomap_ioend *ioend,
237 : struct list_head *more_ioends,
238 : void (*merge_private)(struct iomap_ioend *ioend,
239 : struct iomap_ioend *next));
240 : void iomap_sort_ioends(struct list_head *ioend_list);
241 : int iomap_writepage(struct page *page, struct writeback_control *wbc,
242 : struct iomap_writepage_ctx *wpc,
243 : const struct iomap_writeback_ops *ops);
244 : int iomap_writepages(struct address_space *mapping,
245 : struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
246 : const struct iomap_writeback_ops *ops);
247 :
248 : /*
249 : * Flags for direct I/O ->end_io:
250 : */
251 : #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
252 : #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
253 :
254 : struct iomap_dio_ops {
255 : int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
256 : unsigned flags);
257 : blk_qc_t (*submit_io)(struct inode *inode, struct iomap *iomap,
258 : struct bio *bio, loff_t file_offset);
259 : };
260 :
261 : /*
262 : * Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not
263 : * synchronous.
264 : */
265 : #define IOMAP_DIO_FORCE_WAIT (1 << 0)
266 :
267 : /*
268 : * Do not allocate blocks or zero partial blocks, but instead fall back to
269 : * the caller by returning -EAGAIN. Used to optimize direct I/O writes that
270 : * are not aligned to the file system block size.
271 : */
272 : #define IOMAP_DIO_OVERWRITE_ONLY (1 << 1)
273 :
274 : ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
275 : const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
276 : unsigned int dio_flags);
277 : struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
278 : const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
279 : unsigned int dio_flags);
280 : ssize_t iomap_dio_complete(struct iomap_dio *dio);
281 : int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
282 :
283 : #ifdef CONFIG_SWAP
284 : struct file;
285 : struct swap_info_struct;
286 :
287 : int iomap_swapfile_activate(struct swap_info_struct *sis,
288 : struct file *swap_file, sector_t *pagespan,
289 : const struct iomap_ops *ops);
290 : #else
291 : # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
292 : #endif /* CONFIG_SWAP */
293 :
294 : #endif /* LINUX_IOMAP_H */
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