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_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 : #define IOMAP_F_BUFFER_HEAD (1U << 4)
62 : #define IOMAP_F_XATTR (1U << 5)
63 :
64 : /*
65 : * Flags set by the core iomap code during operations:
66 : *
67 : * IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
68 : * has changed as the result of this write operation.
69 : *
70 : * IOMAP_F_STALE indicates that the iomap is not valid any longer and the file
71 : * range it covers needs to be remapped by the high level before the operation
72 : * can proceed.
73 : */
74 : #define IOMAP_F_SIZE_CHANGED (1U << 8)
75 : #define IOMAP_F_STALE (1U << 9)
76 :
77 : /*
78 : * Flags from 0x1000 up are for file system specific usage:
79 : */
80 : #define IOMAP_F_PRIVATE (1U << 12)
81 :
82 :
83 : /*
84 : * Magic value for addr:
85 : */
86 : #define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
87 :
88 : struct iomap_folio_ops;
89 :
90 : struct iomap {
91 : u64 addr; /* disk offset of mapping, bytes */
92 : loff_t offset; /* file offset of mapping, bytes */
93 : u64 length; /* length of mapping, bytes */
94 : u16 type; /* type of mapping */
95 : u16 flags; /* flags for mapping */
96 : struct block_device *bdev; /* block device for I/O */
97 : struct dax_device *dax_dev; /* dax_dev for dax operations */
98 : void *inline_data;
99 : void *private; /* filesystem private */
100 : const struct iomap_folio_ops *folio_ops;
101 : u64 validity_cookie; /* used with .iomap_valid() */
102 : };
103 :
104 : static inline sector_t iomap_sector(const struct iomap *iomap, loff_t pos)
105 : {
106 859393000 : return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
107 : }
108 :
109 : /*
110 : * Returns the inline data pointer for logical offset @pos.
111 : */
112 : static inline void *iomap_inline_data(const struct iomap *iomap, loff_t pos)
113 : {
114 0 : return iomap->inline_data + pos - iomap->offset;
115 : }
116 :
117 : /*
118 : * Check if the mapping's length is within the valid range for inline data.
119 : * This is used to guard against accessing data beyond the page inline_data
120 : * points at.
121 : */
122 : static inline bool iomap_inline_data_valid(const struct iomap *iomap)
123 : {
124 0 : return iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data);
125 : }
126 :
127 : /*
128 : * When a filesystem sets folio_ops in an iomap mapping it returns, get_folio
129 : * and put_folio will be called for each folio written to. This only applies
130 : * to buffered writes as unbuffered writes will not typically have folios
131 : * associated with them.
132 : *
133 : * When get_folio succeeds, put_folio will always be called to do any
134 : * cleanup work necessary. put_folio is responsible for unlocking and putting
135 : * @folio.
136 : */
137 : struct iomap_folio_ops {
138 : struct folio *(*get_folio)(struct iomap_iter *iter, loff_t pos,
139 : unsigned len);
140 : void (*put_folio)(struct inode *inode, loff_t pos, unsigned copied,
141 : struct folio *folio);
142 :
143 : /*
144 : * Check that the cached iomap still maps correctly to the filesystem's
145 : * internal extent map. FS internal extent maps can change while iomap
146 : * is iterating a cached iomap, so this hook allows iomap to detect that
147 : * the iomap needs to be refreshed during a long running write
148 : * operation.
149 : *
150 : * The filesystem can store internal state (e.g. a sequence number) in
151 : * iomap->validity_cookie when the iomap is first mapped to be able to
152 : * detect changes between mapping time and whenever .iomap_valid() is
153 : * called.
154 : *
155 : * This is called with the folio over the specified file position held
156 : * locked by the iomap code.
157 : */
158 : bool (*iomap_valid)(struct inode *inode, const struct iomap *iomap);
159 : };
160 :
161 : /*
162 : * Flags for iomap_begin / iomap_end. No flag implies a read.
163 : */
164 : #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
165 : #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
166 : #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
167 : #define IOMAP_FAULT (1 << 3) /* mapping for page fault */
168 : #define IOMAP_DIRECT (1 << 4) /* direct I/O */
169 : #define IOMAP_NOWAIT (1 << 5) /* do not block */
170 : #define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */
171 : #define IOMAP_UNSHARE (1 << 7) /* unshare_file_range */
172 : #ifdef CONFIG_FS_DAX
173 : #define IOMAP_DAX (1 << 8) /* DAX mapping */
174 : #else
175 : #define IOMAP_DAX 0
176 : #endif /* CONFIG_FS_DAX */
177 :
178 : struct iomap_ops {
179 : /*
180 : * Return the existing mapping at pos, or reserve space starting at
181 : * pos for up to length, as long as we can do it as a single mapping.
182 : * The actual length is returned in iomap->length.
183 : */
184 : int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
185 : unsigned flags, struct iomap *iomap,
186 : struct iomap *srcmap);
187 :
188 : /*
189 : * Commit and/or unreserve space previous allocated using iomap_begin.
190 : * Written indicates the length of the successful write operation which
191 : * needs to be commited, while the rest needs to be unreserved.
192 : * Written might be zero if no data was written.
193 : */
194 : int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
195 : ssize_t written, unsigned flags, struct iomap *iomap);
196 : };
197 :
198 : /**
199 : * struct iomap_iter - Iterate through a range of a file
200 : * @inode: Set at the start of the iteration and should not change.
201 : * @pos: The current file position we are operating on. It is updated by
202 : * calls to iomap_iter(). Treat as read-only in the body.
203 : * @len: The remaining length of the file segment we're operating on.
204 : * It is updated at the same time as @pos.
205 : * @processed: The number of bytes processed by the body in the most recent
206 : * iteration, or a negative errno. 0 causes the iteration to stop.
207 : * @flags: Zero or more of the iomap_begin flags above.
208 : * @iomap: Map describing the I/O iteration
209 : * @srcmap: Source map for COW operations
210 : */
211 : struct iomap_iter {
212 : struct inode *inode;
213 : loff_t pos;
214 : u64 len;
215 : s64 processed;
216 : unsigned flags;
217 : struct iomap iomap;
218 : struct iomap srcmap;
219 : void *private;
220 : };
221 :
222 : int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops);
223 :
224 : /**
225 : * iomap_length - length of the current iomap iteration
226 : * @iter: iteration structure
227 : *
228 : * Returns the length that the operation applies to for the current iteration.
229 : */
230 5855216309 : static inline u64 iomap_length(const struct iomap_iter *iter)
231 : {
232 5855216309 : u64 end = iter->iomap.offset + iter->iomap.length;
233 :
234 5855216309 : if (iter->srcmap.type != IOMAP_HOLE)
235 31278703 : end = min(end, iter->srcmap.offset + iter->srcmap.length);
236 5855216309 : return min(iter->len, end - iter->pos);
237 : }
238 :
239 : /**
240 : * iomap_iter_srcmap - return the source map for the current iomap iteration
241 : * @i: iteration structure
242 : *
243 : * Write operations on file systems with reflink support might require a
244 : * source and a destination map. This function retourns the source map
245 : * for a given operation, which may or may no be identical to the destination
246 : * map in &i->iomap.
247 : */
248 : static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i)
249 : {
250 8551638953 : if (i->srcmap.type != IOMAP_HOLE)
251 296174453 : return &i->srcmap;
252 8255464500 : return &i->iomap;
253 : }
254 :
255 : ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
256 : const struct iomap_ops *ops);
257 : int iomap_file_buffered_write_punch_delalloc(struct inode *inode,
258 : struct iomap *iomap, loff_t pos, loff_t length, ssize_t written,
259 : int (*punch)(struct inode *inode, loff_t pos, loff_t length));
260 :
261 : int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops);
262 : void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
263 : bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
264 : struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos);
265 : bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
266 : void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len);
267 : int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
268 : const struct iomap_ops *ops);
269 : int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
270 : bool *did_zero, const struct iomap_ops *ops);
271 : int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
272 : const struct iomap_ops *ops);
273 : vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
274 : const struct iomap_ops *ops);
275 : int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
276 : u64 start, u64 len, const struct iomap_ops *ops);
277 : loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
278 : const struct iomap_ops *ops);
279 : loff_t iomap_seek_data(struct inode *inode, loff_t offset,
280 : const struct iomap_ops *ops);
281 : sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
282 : const struct iomap_ops *ops);
283 :
284 : /*
285 : * Structure for writeback I/O completions.
286 : */
287 : struct iomap_ioend {
288 : struct list_head io_list; /* next ioend in chain */
289 : u16 io_type;
290 : u16 io_flags; /* IOMAP_F_* */
291 : u32 io_folios; /* folios added to ioend */
292 : struct inode *io_inode; /* file being written to */
293 : size_t io_size; /* size of the extent */
294 : loff_t io_offset; /* offset in the file */
295 : sector_t io_sector; /* start sector of ioend */
296 : struct bio *io_bio; /* bio being built */
297 : struct bio io_inline_bio; /* MUST BE LAST! */
298 : };
299 :
300 : struct iomap_writeback_ops {
301 : /*
302 : * Required, maps the blocks so that writeback can be performed on
303 : * the range starting at offset.
304 : */
305 : int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
306 : loff_t offset);
307 :
308 : /*
309 : * Optional, allows the file systems to perform actions just before
310 : * submitting the bio and/or override the bio end_io handler for complex
311 : * operations like copy on write extent manipulation or unwritten extent
312 : * conversions.
313 : */
314 : int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
315 :
316 : /*
317 : * Optional, allows the file system to discard state on a page where
318 : * we failed to submit any I/O.
319 : */
320 : void (*discard_folio)(struct folio *folio, loff_t pos);
321 : };
322 :
323 : struct iomap_writepage_ctx {
324 : struct iomap iomap;
325 : struct iomap_ioend *ioend;
326 : const struct iomap_writeback_ops *ops;
327 : };
328 :
329 : void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
330 : void iomap_ioend_try_merge(struct iomap_ioend *ioend,
331 : struct list_head *more_ioends);
332 : void iomap_sort_ioends(struct list_head *ioend_list);
333 : int iomap_writepages(struct address_space *mapping,
334 : struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
335 : const struct iomap_writeback_ops *ops);
336 :
337 : /*
338 : * Flags for direct I/O ->end_io:
339 : */
340 : #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
341 : #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
342 :
343 : struct iomap_dio_ops {
344 : int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
345 : unsigned flags);
346 : void (*submit_io)(const struct iomap_iter *iter, struct bio *bio,
347 : loff_t file_offset);
348 :
349 : /*
350 : * Filesystems wishing to attach private information to a direct io bio
351 : * must provide a ->submit_io method that attaches the additional
352 : * information to the bio and changes the ->bi_end_io callback to a
353 : * custom function. This function should, at a minimum, perform any
354 : * relevant post-processing of the bio and end with a call to
355 : * iomap_dio_bio_end_io.
356 : */
357 : struct bio_set *bio_set;
358 : };
359 :
360 : /*
361 : * Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not
362 : * synchronous.
363 : */
364 : #define IOMAP_DIO_FORCE_WAIT (1 << 0)
365 :
366 : /*
367 : * Do not allocate blocks or zero partial blocks, but instead fall back to
368 : * the caller by returning -EAGAIN. Used to optimize direct I/O writes that
369 : * are not aligned to the file system block size.
370 : */
371 : #define IOMAP_DIO_OVERWRITE_ONLY (1 << 1)
372 :
373 : /*
374 : * When a page fault occurs, return a partial synchronous result and allow
375 : * the caller to retry the rest of the operation after dealing with the page
376 : * fault.
377 : */
378 : #define IOMAP_DIO_PARTIAL (1 << 2)
379 :
380 : ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
381 : const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
382 : unsigned int dio_flags, void *private, size_t done_before);
383 : struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
384 : const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
385 : unsigned int dio_flags, void *private, size_t done_before);
386 : ssize_t iomap_dio_complete(struct iomap_dio *dio);
387 : void iomap_dio_bio_end_io(struct bio *bio);
388 :
389 : #ifdef CONFIG_SWAP
390 : struct file;
391 : struct swap_info_struct;
392 :
393 : int iomap_swapfile_activate(struct swap_info_struct *sis,
394 : struct file *swap_file, sector_t *pagespan,
395 : const struct iomap_ops *ops);
396 : #else
397 : # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
398 : #endif /* CONFIG_SWAP */
399 :
400 : #endif /* LINUX_IOMAP_H */
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