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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)
333 ssize_t
iomap_dio_rw(struct kiocb
*iocb
, struct iov_iter
*iter
,
334 const struct iomap_ops
*ops
, const struct iomap_dio_ops
*dops
,
335 unsigned int dio_flags
);
336 struct iomap_dio
*__iomap_dio_rw(struct kiocb
*iocb
, struct iov_iter
*iter
,
337 const struct iomap_ops
*ops
, const struct iomap_dio_ops
*dops
,
338 unsigned int dio_flags
);
339 ssize_t
iomap_dio_complete(struct iomap_dio
*dio
);
340 int iomap_dio_iopoll(struct kiocb
*kiocb
, bool spin
);
344 struct swap_info_struct
;
346 int iomap_swapfile_activate(struct swap_info_struct
*sis
,
347 struct file
*swap_file
, sector_t
*pagespan
,
348 const struct iomap_ops
*ops
);
350 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
351 #endif /* CONFIG_SWAP */
353 #endif /* LINUX_IOMAP_H */