1 /* SPDX-License-Identifier: GPL-2.0 */
3 #define LINUX_IOMAP_H 1
5 #include <linux/atomic.h>
6 #include <linux/bitmap.h>
7 #include <linux/blk_types.h>
9 #include <linux/types.h>
10 #include <linux/mm_types.h>
11 #include <linux/blkdev.h>
14 struct fiemap_extent_info;
17 struct iomap_writepage_ctx;
21 struct vm_area_struct;
25 * Types of block ranges for iomap mappings:
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 */
34 * Flags reported by the file system from iomap_begin:
36 * IOMAP_F_NEW indicates that the blocks have been newly allocated and need
37 * zeroing for areas that no data is copied to.
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.
44 * IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
45 * unshared as part a write.
47 * IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
50 * IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
51 * buffer heads for this mapping.
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
61 * Flags set by the core iomap code during operations:
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.
66 #define IOMAP_F_SIZE_CHANGED 0x100
69 * Flags from 0x1000 up are for file system specific usage:
71 #define IOMAP_F_PRIVATE 0x1000
75 * Magic value for addr:
77 #define IOMAP_NULL_ADDR -1ULL /* addr is not valid */
79 struct iomap_page_ops;
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 */
90 void *private; /* filesystem private */
91 const struct iomap_page_ops *page_ops;
94 static inline sector_t iomap_sector(const struct iomap *iomap, loff_t pos)
96 return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
100 * Returns the inline data pointer for logical offset @pos.
102 static inline void *iomap_inline_data(const struct iomap *iomap, loff_t pos)
104 return iomap->inline_data + pos - iomap->offset;
108 * Check if the mapping's length is within the valid range for inline data.
109 * This is used to guard against accessing data beyond the page inline_data
112 static inline bool iomap_inline_data_valid(const struct iomap *iomap)
114 return iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data);
118 * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
119 * and page_done will be called for each page written to. This only applies to
120 * buffered writes as unbuffered writes will not typically have pages
121 * associated with them.
123 * When page_prepare succeeds, page_done will always be called to do any
124 * cleanup work necessary. In that page_done call, @page will be NULL if the
125 * associated page could not be obtained.
127 struct iomap_page_ops {
128 int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len);
129 void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
134 * Flags for iomap_begin / iomap_end. No flag implies a read.
136 #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
137 #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
138 #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
139 #define IOMAP_FAULT (1 << 3) /* mapping for page fault */
140 #define IOMAP_DIRECT (1 << 4) /* direct I/O */
141 #define IOMAP_NOWAIT (1 << 5) /* do not block */
142 #define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */
143 #define IOMAP_UNSHARE (1 << 7) /* unshare_file_range */
147 * Return the existing mapping at pos, or reserve space starting at
148 * pos for up to length, as long as we can do it as a single mapping.
149 * The actual length is returned in iomap->length.
151 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
152 unsigned flags, struct iomap *iomap,
153 struct iomap *srcmap);
156 * Commit and/or unreserve space previous allocated using iomap_begin.
157 * Written indicates the length of the successful write operation which
158 * needs to be commited, while the rest needs to be unreserved.
159 * Written might be zero if no data was written.
161 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
162 ssize_t written, unsigned flags, struct iomap *iomap);
166 * struct iomap_iter - Iterate through a range of a file
167 * @inode: Set at the start of the iteration and should not change.
168 * @pos: The current file position we are operating on. It is updated by
169 * calls to iomap_iter(). Treat as read-only in the body.
170 * @len: The remaining length of the file segment we're operating on.
171 * It is updated at the same time as @pos.
172 * @processed: The number of bytes processed by the body in the most recent
173 * iteration, or a negative errno. 0 causes the iteration to stop.
174 * @flags: Zero or more of the iomap_begin flags above.
175 * @iomap: Map describing the I/O iteration
176 * @srcmap: Source map for COW operations
188 int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops);
191 * iomap_length - length of the current iomap iteration
192 * @iter: iteration structure
194 * Returns the length that the operation applies to for the current iteration.
196 static inline u64 iomap_length(const struct iomap_iter *iter)
198 u64 end = iter->iomap.offset + iter->iomap.length;
200 if (iter->srcmap.type != IOMAP_HOLE)
201 end = min(end, iter->srcmap.offset + iter->srcmap.length);
202 return min(iter->len, end - iter->pos);
206 * iomap_iter_srcmap - return the source map for the current iomap iteration
207 * @i: iteration structure
209 * Write operations on file systems with reflink support might require a
210 * source and a destination map. This function retourns the source map
211 * for a given operation, which may or may no be identical to the destination
214 static inline const struct iomap *iomap_iter_srcmap(const struct iomap_iter *i)
216 if (i->srcmap.type != IOMAP_HOLE)
221 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
222 const struct iomap_ops *ops);
223 int iomap_readpage(struct page *page, const struct iomap_ops *ops);
224 void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
225 int iomap_is_partially_uptodate(struct page *page, unsigned long from,
226 unsigned long count);
227 int iomap_releasepage(struct page *page, gfp_t gfp_mask);
228 void iomap_invalidatepage(struct page *page, unsigned int offset,
230 #ifdef CONFIG_MIGRATION
231 int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
232 struct page *page, enum migrate_mode mode);
234 #define iomap_migrate_page NULL
236 int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
237 const struct iomap_ops *ops);
238 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
239 bool *did_zero, const struct iomap_ops *ops);
240 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
241 const struct iomap_ops *ops);
242 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
243 const struct iomap_ops *ops);
244 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
245 u64 start, u64 len, const struct iomap_ops *ops);
246 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
247 const struct iomap_ops *ops);
248 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
249 const struct iomap_ops *ops);
250 sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
251 const struct iomap_ops *ops);
254 * Structure for writeback I/O completions.
257 struct list_head io_list; /* next ioend in chain */
259 u16 io_flags; /* IOMAP_F_* */
260 struct inode *io_inode; /* file being written to */
261 size_t io_size; /* size of the extent */
262 loff_t io_offset; /* offset in the file */
263 struct bio *io_bio; /* bio being built */
264 struct bio io_inline_bio; /* MUST BE LAST! */
267 struct iomap_writeback_ops {
269 * Required, maps the blocks so that writeback can be performed on
270 * the range starting at offset.
272 int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
276 * Optional, allows the file systems to perform actions just before
277 * submitting the bio and/or override the bio end_io handler for complex
278 * operations like copy on write extent manipulation or unwritten extent
281 int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
284 * Optional, allows the file system to discard state on a page where
285 * we failed to submit any I/O.
287 void (*discard_page)(struct page *page, loff_t fileoff);
290 struct iomap_writepage_ctx {
292 struct iomap_ioend *ioend;
293 const struct iomap_writeback_ops *ops;
296 void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
297 void iomap_ioend_try_merge(struct iomap_ioend *ioend,
298 struct list_head *more_ioends);
299 void iomap_sort_ioends(struct list_head *ioend_list);
300 int iomap_writepage(struct page *page, struct writeback_control *wbc,
301 struct iomap_writepage_ctx *wpc,
302 const struct iomap_writeback_ops *ops);
303 int iomap_writepages(struct address_space *mapping,
304 struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
305 const struct iomap_writeback_ops *ops);
308 * Flags for direct I/O ->end_io:
310 #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
311 #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
313 struct iomap_dio_ops {
314 int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
316 blk_qc_t (*submit_io)(const struct iomap_iter *iter, struct bio *bio,
321 * Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not
324 #define IOMAP_DIO_FORCE_WAIT (1 << 0)
327 * Do not allocate blocks or zero partial blocks, but instead fall back to
328 * the caller by returning -EAGAIN. Used to optimize direct I/O writes that
329 * are not aligned to the file system block size.
331 #define IOMAP_DIO_OVERWRITE_ONLY (1 << 1)
334 * When a page fault occurs, return a partial synchronous result and allow
335 * the caller to retry the rest of the operation after dealing with the page
338 #define IOMAP_DIO_PARTIAL (1 << 2)
340 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
341 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
342 unsigned int dio_flags, size_t done_before);
343 struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
344 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
345 unsigned int dio_flags, size_t done_before);
346 ssize_t iomap_dio_complete(struct iomap_dio *dio);
347 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
351 struct swap_info_struct;
353 int iomap_swapfile_activate(struct swap_info_struct *sis,
354 struct file *swap_file, sector_t *pagespan,
355 const struct iomap_ops *ops);
357 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
358 #endif /* CONFIG_SWAP */
360 #endif /* LINUX_IOMAP_H */