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 #include <linux/android_kabi.h>
13
14 struct address_space;
15 struct fiemap_extent_info;
16 struct inode;
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 #define IOMAP_F_NEW 0x01
55 #define IOMAP_F_DIRTY 0x02
56 #define IOMAP_F_SHARED 0x04
57 #define IOMAP_F_MERGED 0x08
58 #define IOMAP_F_BUFFER_HEAD 0x10
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 ANDROID_KABI_RESERVE(1);
94 };
95
96 static inline sector_t
iomap_sector(struct iomap * iomap,loff_t pos)97 iomap_sector(struct iomap *iomap, loff_t pos)
98 {
99 return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
100 }
101
102 /*
103 * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
104 * and page_done will be called for each page written to. This only applies to
105 * buffered writes as unbuffered writes will not typically have pages
106 * associated with them.
107 *
108 * When page_prepare succeeds, page_done will always be called to do any
109 * cleanup work necessary. In that page_done call, @page will be NULL if the
110 * associated page could not be obtained.
111 */
112 struct iomap_page_ops {
113 int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
114 struct iomap *iomap);
115 void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
116 struct page *page, struct iomap *iomap);
117 };
118
119 /*
120 * Flags for iomap_begin / iomap_end. No flag implies a read.
121 */
122 #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */
123 #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */
124 #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */
125 #define IOMAP_FAULT (1 << 3) /* mapping for page fault */
126 #define IOMAP_DIRECT (1 << 4) /* direct I/O */
127 #define IOMAP_NOWAIT (1 << 5) /* do not block */
128
129 struct iomap_ops {
130 /*
131 * Return the existing mapping at pos, or reserve space starting at
132 * pos for up to length, as long as we can do it as a single mapping.
133 * The actual length is returned in iomap->length.
134 */
135 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
136 unsigned flags, struct iomap *iomap,
137 struct iomap *srcmap);
138
139 /*
140 * Commit and/or unreserve space previous allocated using iomap_begin.
141 * Written indicates the length of the successful write operation which
142 * needs to be commited, while the rest needs to be unreserved.
143 * Written might be zero if no data was written.
144 */
145 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
146 ssize_t written, unsigned flags, struct iomap *iomap);
147
148 ANDROID_KABI_RESERVE(1);
149 ANDROID_KABI_RESERVE(2);
150 };
151
152 /*
153 * Main iomap iterator function.
154 */
155 typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
156 void *data, struct iomap *iomap, struct iomap *srcmap);
157
158 loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
159 unsigned flags, const struct iomap_ops *ops, void *data,
160 iomap_actor_t actor);
161
162 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
163 const struct iomap_ops *ops);
164 int iomap_readpage(struct page *page, const struct iomap_ops *ops);
165 void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
166 int iomap_set_page_dirty(struct page *page);
167 int iomap_is_partially_uptodate(struct page *page, unsigned long from,
168 unsigned long count);
169 int iomap_releasepage(struct page *page, gfp_t gfp_mask);
170 void iomap_invalidatepage(struct page *page, unsigned int offset,
171 unsigned int len);
172 #ifdef CONFIG_MIGRATION
173 int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
174 struct page *page, enum migrate_mode mode);
175 #else
176 #define iomap_migrate_page NULL
177 #endif
178 int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
179 const struct iomap_ops *ops);
180 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
181 bool *did_zero, const struct iomap_ops *ops);
182 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
183 const struct iomap_ops *ops);
184 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
185 const struct iomap_ops *ops);
186 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
187 u64 start, u64 len, const struct iomap_ops *ops);
188 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
189 const struct iomap_ops *ops);
190 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
191 const struct iomap_ops *ops);
192 sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
193 const struct iomap_ops *ops);
194
195 /*
196 * Structure for writeback I/O completions.
197 */
198 struct iomap_ioend {
199 struct list_head io_list; /* next ioend in chain */
200 u16 io_type;
201 u16 io_flags; /* IOMAP_F_* */
202 struct inode *io_inode; /* file being written to */
203 size_t io_size; /* size of the extent */
204 loff_t io_offset; /* offset in the file */
205 void *io_private; /* file system private data */
206 struct bio *io_bio; /* bio being built */
207 struct bio io_inline_bio; /* MUST BE LAST! */
208 };
209
210 struct iomap_writeback_ops {
211 /*
212 * Required, maps the blocks so that writeback can be performed on
213 * the range starting at offset.
214 */
215 int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode,
216 loff_t offset);
217
218 /*
219 * Optional, allows the file systems to perform actions just before
220 * submitting the bio and/or override the bio end_io handler for complex
221 * operations like copy on write extent manipulation or unwritten extent
222 * conversions.
223 */
224 int (*prepare_ioend)(struct iomap_ioend *ioend, int status);
225
226 /*
227 * Optional, allows the file system to discard state on a page where
228 * we failed to submit any I/O.
229 */
230 void (*discard_page)(struct page *page, loff_t fileoff);
231 };
232
233 struct iomap_writepage_ctx {
234 struct iomap iomap;
235 struct iomap_ioend *ioend;
236 const struct iomap_writeback_ops *ops;
237 };
238
239 void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
240 void iomap_ioend_try_merge(struct iomap_ioend *ioend,
241 struct list_head *more_ioends,
242 void (*merge_private)(struct iomap_ioend *ioend,
243 struct iomap_ioend *next));
244 void iomap_sort_ioends(struct list_head *ioend_list);
245 int iomap_writepage(struct page *page, struct writeback_control *wbc,
246 struct iomap_writepage_ctx *wpc,
247 const struct iomap_writeback_ops *ops);
248 int iomap_writepages(struct address_space *mapping,
249 struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
250 const struct iomap_writeback_ops *ops);
251
252 /*
253 * Flags for direct I/O ->end_io:
254 */
255 #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */
256 #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */
257
258 struct iomap_dio_ops {
259 int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
260 unsigned flags);
261 blk_qc_t (*submit_io)(struct inode *inode, struct iomap *iomap,
262 struct bio *bio, loff_t file_offset);
263 };
264
265 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
266 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
267 bool wait_for_completion);
268 struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
269 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
270 bool wait_for_completion);
271 ssize_t iomap_dio_complete(struct iomap_dio *dio);
272 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
273
274 #ifdef CONFIG_SWAP
275 struct file;
276 struct swap_info_struct;
277
278 int iomap_swapfile_activate(struct swap_info_struct *sis,
279 struct file *swap_file, sector_t *pagespan,
280 const struct iomap_ops *ops);
281 #else
282 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO)
283 #endif /* CONFIG_SWAP */
284
285 #endif /* LINUX_IOMAP_H */
286