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_iter;
17 struct iomap_dio;
18 struct iomap_writepage_ctx;
19 struct iov_iter;
20 struct kiocb;
21 struct page;
22 struct vm_area_struct;
23 struct vm_fault;
24
25 /*
26 * Types of block ranges for iomap mappings:
27 */
28 #define IOMAP_HOLE 0 /* no blocks allocated, need allocation */
29 #define IOMAP_DELALLOC 1 /* delayed allocation blocks */
30 #define IOMAP_MAPPED 2 /* blocks allocated at @addr */
31 #define IOMAP_UNWRITTEN 3 /* blocks allocated at @addr in unwritten state */
32 #define IOMAP_INLINE 4 /* data inline in the inode */
33
34 /*
35 * Flags reported by the file system from iomap_begin:
36 *
37 * IOMAP_F_NEW indicates that the blocks have been newly allocated and need
38 * zeroing for areas that no data is copied to.
39 *
40 * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
41 * written data and requires fdatasync to commit them to persistent storage.
42 * This needs to take into account metadata changes that *may* be made at IO
43 * completion, such as file size updates from direct IO.
44 *
45 * IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
46 * unshared as part a write.
47 *
48 * IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
49 * mappings.
50 *
51 * IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
52 * buffer heads for this mapping.
53 *
54 * IOMAP_F_XATTR indicates that the iomap is for an extended attribute extent
55 * rather than a file data extent.
56 */
57 #define IOMAP_F_NEW (1U << 0)
58 #define IOMAP_F_DIRTY (1U << 1)
59 #define IOMAP_F_SHARED (1U << 2)
60 #define IOMAP_F_MERGED (1U << 3)
61 #ifdef CONFIG_BUFFER_HEAD
62 #define IOMAP_F_BUFFER_HEAD (1U << 4)
63 #else
64 #define IOMAP_F_BUFFER_HEAD 0
65 #endif /* CONFIG_BUFFER_HEAD */
66 #define IOMAP_F_XATTR (1U << 5)
67
68 /*
69 * Flags set by the core iomap code during operations:
70 *
71 * IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
72 * has changed as the result of this write operation.
73 *
74 * IOMAP_F_STALE indicates that the iomap is not valid any longer and the file
75 * range it covers needs to be remapped by the high level before the operation
76 * can proceed.
77 */
78 #define IOMAP_F_SIZE_CHANGED (1U << 8)
79 #define IOMAP_F_STALE (1U << 9)
80
81 /*
82 * Flags from 0x1000 up are for file system specific usage:
83 */
84 #define IOMAP_F_PRIVATE (1U << 12)
85
86
87 /*
88 * Magic value for addr:
89 */
90 #define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
91
92 struct iomap_folio_ops;
93
94 struct iomap {
95 u64 addr; /* disk offset of mapping, bytes */
96 loff_t offset; /* file offset of mapping, bytes */
97 u64 length; /* length of mapping, bytes */
98 u16 type; /* type of mapping */
99 u16 flags; /* flags for mapping */
100 struct block_device *bdev; /* block device for I/O */
101 struct dax_device *dax_dev; /* dax_dev for dax operations */
102 void *inline_data;
103 void *private; /* filesystem private */
104 const struct iomap_folio_ops *folio_ops;
105 u64 validity_cookie; /* used with .iomap_valid() */
106 };
107
108 static inline sector_t iomap_sector(const struct iomap *iomap, loff_t pos)
109 {
110 return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
111 }
112
113 /*
114 * Returns the inline data pointer for logical offset @pos.
115 */
116 static inline void *iomap_inline_data(const struct iomap *iomap, loff_t pos)
117 {
118 return iomap->inline_data + pos - iomap->offset;
119 }
120
121 /*
122 * Check if the mapping's length is within the valid range for inline data.
123 * This is used to guard against accessing data beyond the page inline_data
124 * points at.
125 */
126 static inline bool iomap_inline_data_valid(const struct iomap *iomap)
127 {
128 return iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data);
129 }
130
131 /*
132 * When a filesystem sets folio_ops in an iomap mapping it returns, get_folio
133 * and put_folio will be called for each folio written to. This only applies
134 * to buffered writes as unbuffered writes will not typically have folios
135 * associated with them.
136 *
137 * When get_folio succeeds, put_folio will always be called to do any
138 * cleanup work necessary. put_folio is responsible for unlocking and putting
139 * @folio.
140 */
141 struct iomap_folio_ops {
142 struct folio *(*get_folio)(struct iomap_iter *iter, loff_t pos,
143 unsigned len);
144 void (*put_folio)(struct inode *inode, loff_t pos, unsigned copied,
145 struct folio *folio);
146
147 /*
148 * Check that the cached iomap still maps correctly to the filesystem's
149 * internal extent map. FS internal extent maps can change while iomap
150 * is iterating a cached iomap, so this hook allows iomap to detect that
151 * the iomap needs to be refreshed during a long running write
152 * operation.
153 *
154 * The filesystem can store internal state (e.g. a sequence number) in
155 * iomap->validity_cookie when the iomap is first mapped to be able to
156 * detect changes between mapping time and whenever .iomap_valid() is
157 * called.
158 *
159 * This is called with the folio over the specified file position held
160 * locked by the iomap code.
161 */
162 bool (*iomap_valid)(struct inode *inode, const struct iomap *iomap);
163 };
164
165 /*
166 * Flags for iomap_begin / iomap_end. No flag implies a read.
167 */
168 #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
169 #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
170 #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
171 #define IOMAP_FAULT (1 << 3) /* mapping for page fault */
172 #define IOMAP_DIRECT (1 << 4) /* direct I/O */
173 #define IOMAP_NOWAIT (1 << 5) /* do not block */
174 #define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */
175 #define IOMAP_UNSHARE (1 << 7) /* unshare_file_range */
176 #ifdef CONFIG_FS_DAX
177 #define IOMAP_DAX (1 << 8) /* DAX mapping */
178 #else
179 #define IOMAP_DAX 0
180 #endif /* CONFIG_FS_DAX */
181
182 struct iomap_ops {
183 /*
184 * Return the existing mapping at pos, or reserve space starting at
185 * pos for up to length, as long as we can do it as a single mapping.
186 * The actual length is returned in iomap->length.
187 */
188 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
189 unsigned flags, struct iomap *iomap,
190 struct iomap *srcmap);
191
192 /*
193 * Commit and/or unreserve space previous allocated using iomap_begin.
194 * Written indicates the length of the successful write operation which
195 * needs to be commited, while the rest needs to be unreserved.
196 * Written might be zero if no data was written.
197 */
198 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
199 ssize_t written, unsigned flags, struct iomap *iomap);
200 };
201
202 /**
203 * struct iomap_iter - Iterate through a range of a file
204 * @inode: Set at the start of the iteration and should not change.
205 * @pos: The current file position we are operating on. It is updated by
206 * calls to iomap_iter(). Treat as read-only in the body.
207 * @len: The remaining length of the file segment we're operating on.
208 * It is updated at the same time as @pos.
209 * @processed: The number of bytes processed by the body in the most recent
210 * iteration, or a negative errno. 0 causes the iteration to stop.
211 * @flags: Zero or more of the iomap_begin flags above.
212 * @iomap: Map describing the I/O iteration
213 * @srcmap: Source map for COW operations
214 */
215 struct iomap_iter {
216 struct inode *inode;
217 loff_t pos;
218 u64 len;
219 s64 processed;
220 unsigned flags;
221 struct iomap iomap;
222 struct iomap srcmap;
223 void *private;
224 };
225
226 int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops);
227
228 /**
229 * iomap_length - length of the current iomap iteration
230 * @iter: iteration structure
231 *
232 * Returns the length that the operation applies to for the current iteration.
233 */
234 static inline u64 iomap_length(const struct iomap_iter *iter)
235 {
236 u64 end = iter->iomap.offset + iter->iomap.length;
237
238 if (iter->srcmap.type != IOMAP_HOLE)
239 end = min(end, iter->srcmap.offset + iter->srcmap.length);
240 return min(iter->len, end - iter->pos);
241 }
242
243 /**
244 * iomap_iter_srcmap - return the source map for the current iomap iteration
245 * @i: iteration structure
246 *
247 * Write operations on file systems with reflink support might require a
248 * source and a destination map. This function retourns the source map
249 * for a given operation, which may or may no be identical to the destination
250 * map in &i->iomap.
251 */
252 static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i)
253 {
254 if (i->srcmap.type != IOMAP_HOLE)
255 return &i->srcmap;
256 return &i->iomap;
257 }
258
259 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
260 const struct iomap_ops *ops);
261 int iomap_file_buffered_write_punch_delalloc(struct inode *inode,
262 struct iomap *iomap, loff_t pos, loff_t length, ssize_t written,
263 int (*punch)(struct inode *inode, loff_t pos, loff_t length));
264
265 int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
266 void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
267 bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
268 struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len);
269 bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
270 void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);
271 bool iomap_dirty_folio(struct address_space *mapping, struct folio *folio);
272 int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
273 const struct iomap_ops *ops);
274 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
275 bool *did_zero, const struct iomap_ops *ops);
276 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
277 const struct iomap_ops *ops);
278 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
279 const struct iomap_ops *ops);
280 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
281 u64 start, u64 len, const struct iomap_ops *ops);
282 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
283 const struct iomap_ops *ops);
284 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
285 const struct iomap_ops *ops);
286 sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
287 const struct iomap_ops *ops);
288
289 /*
290 * Structure for writeback I/O completions.
291 */
292 struct iomap_ioend {
293 struct list_head io_list; /* next ioend in chain */
294 u16 io_type;
295 u16 io_flags; /* IOMAP_F_* */
296 struct inode *io_inode; /* file being written to */
297 size_t io_size; /* size of the extent */
298 loff_t io_offset; /* offset in the file */
299 sector_t io_sector; /* start sector of ioend */
300 struct bio io_bio; /* MUST BE LAST! */
301 };
302
303 static inline struct iomap_ioend *iomap_ioend_from_bio(struct bio *bio)
304 {
305 return container_of(bio, struct iomap_ioend, io_bio);
306 }
307
308 struct iomap_writeback_ops {
309 /*
310 * Required, maps the blocks so that writeback can be performed on
311 * the range starting at offset.
312 *
313 * Can return arbitrarily large regions, but we need to call into it at
314 * least once per folio to allow the file systems to synchronize with
315 * the write path that could be invalidating mappings.
316 *
317 * An existing mapping from a previous call to this method can be reused
318 * by the file system if it is still valid.
319 */
320 int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
321 loff_t offset, unsigned len);
322
323 /*
324 * Optional, allows the file systems to perform actions just before
325 * submitting the bio and/or override the bio end_io handler for complex
326 * operations like copy on write extent manipulation or unwritten extent
327 * conversions.
328 */
329 int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
330
331 /*
332 * Optional, allows the file system to discard state on a page where
333 * we failed to submit any I/O.
334 */
335 void (*discard_folio)(struct folio *folio, loff_t pos);
336 };
337
338 struct iomap_writepage_ctx {
339 struct iomap iomap;
340 struct iomap_ioend *ioend;
341 const struct iomap_writeback_ops *ops;
342 u32 nr_folios; /* folios added to the ioend */
343 };
344
345 void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
346 void iomap_ioend_try_merge(struct iomap_ioend *ioend,
347 struct list_head *more_ioends);
348 void iomap_sort_ioends(struct list_head *ioend_list);
349 int iomap_writepages(struct address_space *mapping,
350 struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
351 const struct iomap_writeback_ops *ops);
352
353 /*
354 * Flags for direct I/O ->end_io:
355 */
356 #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
357 #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
358
359 struct iomap_dio_ops {
360 int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
361 unsigned flags);
362 void (*submit_io)(const struct iomap_iter *iter, struct bio *bio,
363 loff_t file_offset);
364
365 /*
366 * Filesystems wishing to attach private information to a direct io bio
367 * must provide a ->submit_io method that attaches the additional
368 * information to the bio and changes the ->bi_end_io callback to a
369 * custom function. This function should, at a minimum, perform any
370 * relevant post-processing of the bio and end with a call to
371 * iomap_dio_bio_end_io.
372 */
373 struct bio_set *bio_set;
374 };
375
376 /*
377 * Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not
378 * synchronous.
379 */
380 #define IOMAP_DIO_FORCE_WAIT (1 << 0)
381
382 /*
383 * Do not allocate blocks or zero partial blocks, but instead fall back to
384 * the caller by returning -EAGAIN. Used to optimize direct I/O writes that
385 * are not aligned to the file system block size.
386 */
387 #define IOMAP_DIO_OVERWRITE_ONLY (1 << 1)
388
389 /*
390 * When a page fault occurs, return a partial synchronous result and allow
391 * the caller to retry the rest of the operation after dealing with the page
392 * fault.
393 */
394 #define IOMAP_DIO_PARTIAL (1 << 2)
395
396 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
397 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
398 unsigned int dio_flags, void *private, size_t done_before);
399 struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
400 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
401 unsigned int dio_flags, void *private, size_t done_before);
402 ssize_t iomap_dio_complete(struct iomap_dio *dio);
403 void iomap_dio_bio_end_io(struct bio *bio);
404
405 #ifdef CONFIG_SWAP
406 struct file;
407 struct swap_info_struct;
408
409 int iomap_swapfile_activate(struct swap_info_struct *sis,
410 struct file *swap_file, sector_t *pagespan,
411 const struct iomap_ops *ops);
412 #else
413 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
414 #endif /* CONFIG_SWAP */
415
416 #endif /* LINUX_IOMAP_H */
417
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