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_writepage_ctx; 17 struct iov_iter; 18 struct kiocb; 19 struct page; 20 struct vm_area_struct; 21 struct vm_fault; 22 23 /* 24 * Types of block ranges for iomap mappings: 25 */ 26 #define IOMAP_HOLE 0 /* no blocks allocated, need allocation */ 27 #define IOMAP_DELALLOC 1 /* delayed allocation blocks */ 28 #define IOMAP_MAPPED 2 /* blocks allocated at @addr */ 29 #define IOMAP_UNWRITTEN 3 /* blocks allocated at @addr in unwritten state */ 30 #define IOMAP_INLINE 4 /* data inline in the inode */ 31 32 /* 33 * Flags reported by the file system from iomap_begin: 34 * 35 * IOMAP_F_NEW indicates that the blocks have been newly allocated and need 36 * zeroing for areas that no data is copied to. 37 * 38 * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access 39 * written data and requires fdatasync to commit them to persistent storage. 40 * This needs to take into account metadata changes that *may* be made at IO 41 * completion, such as file size updates from direct IO. 42 * 43 * IOMAP_F_SHARED indicates that the blocks are shared, and will need to be 44 * unshared as part a write. 45 * 46 * IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block 47 * mappings. 48 * 49 * IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of 50 * buffer heads for this mapping. 51 */ 52 #define IOMAP_F_NEW 0x01 53 #define IOMAP_F_DIRTY 0x02 54 #define IOMAP_F_SHARED 0x04 55 #define IOMAP_F_MERGED 0x08 56 #define IOMAP_F_BUFFER_HEAD 0x10 57 58 /* 59 * Flags set by the core iomap code during operations: 60 * 61 * IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size 62 * has changed as the result of this write operation. 63 */ 64 #define IOMAP_F_SIZE_CHANGED 0x100 65 66 /* 67 * Flags from 0x1000 up are for file system specific usage: 68 */ 69 #define IOMAP_F_PRIVATE 0x1000 70 71 72 /* 73 * Magic value for addr: 74 */ 75 #define IOMAP_NULL_ADDR -1ULL /* addr is not valid */ 76 77 struct iomap_page_ops; 78 79 struct iomap { 80 u64 addr; /* disk offset of mapping, bytes */ 81 loff_t offset; /* file offset of mapping, bytes */ 82 u64 length; /* length of mapping, bytes */ 83 u16 type; /* type of mapping */ 84 u16 flags; /* flags for mapping */ 85 struct block_device *bdev; /* block device for I/O */ 86 struct dax_device *dax_dev; /* dax_dev for dax operations */ 87 void *inline_data; 88 void *private; /* filesystem private */ 89 const struct iomap_page_ops *page_ops; 90 }; 91 92 static inline sector_t 93 iomap_sector(struct iomap *iomap, loff_t pos) 94 { 95 return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; 96 } 97 98 /* 99 * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare 100 * and page_done will be called for each page written to. This only applies to 101 * buffered writes as unbuffered writes will not typically have pages 102 * associated with them. 103 * 104 * When page_prepare succeeds, page_done will always be called to do any 105 * cleanup work necessary. In that page_done call, @page will be NULL if the 106 * associated page could not be obtained. 107 */ 108 struct iomap_page_ops { 109 int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len, 110 struct iomap *iomap); 111 void (*page_done)(struct inode *inode, loff_t pos, unsigned copied, 112 struct page *page, struct iomap *iomap); 113 }; 114 115 /* 116 * Flags for iomap_begin / iomap_end. No flag implies a read. 117 */ 118 #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */ 119 #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */ 120 #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */ 121 #define IOMAP_FAULT (1 << 3) /* mapping for page fault */ 122 #define IOMAP_DIRECT (1 << 4) /* direct I/O */ 123 #define IOMAP_NOWAIT (1 << 5) /* do not block */ 124 125 struct iomap_ops { 126 /* 127 * Return the existing mapping at pos, or reserve space starting at 128 * pos for up to length, as long as we can do it as a single mapping. 129 * The actual length is returned in iomap->length. 130 */ 131 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length, 132 unsigned flags, struct iomap *iomap, 133 struct iomap *srcmap); 134 135 /* 136 * Commit and/or unreserve space previous allocated using iomap_begin. 137 * Written indicates the length of the successful write operation which 138 * needs to be commited, while the rest needs to be unreserved. 139 * Written might be zero if no data was written. 140 */ 141 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length, 142 ssize_t written, unsigned flags, struct iomap *iomap); 143 }; 144 145 /* 146 * Main iomap iterator function. 147 */ 148 typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len, 149 void *data, struct iomap *iomap, struct iomap *srcmap); 150 151 loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, 152 unsigned flags, const struct iomap_ops *ops, void *data, 153 iomap_actor_t actor); 154 155 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, 156 const struct iomap_ops *ops); 157 int iomap_readpage(struct page *page, const struct iomap_ops *ops); 158 int iomap_readpages(struct address_space *mapping, struct list_head *pages, 159 unsigned nr_pages, const struct iomap_ops *ops); 160 int iomap_set_page_dirty(struct page *page); 161 int iomap_is_partially_uptodate(struct page *page, unsigned long from, 162 unsigned long count); 163 int iomap_releasepage(struct page *page, gfp_t gfp_mask); 164 void iomap_invalidatepage(struct page *page, unsigned int offset, 165 unsigned int len); 166 #ifdef CONFIG_MIGRATION 167 int iomap_migrate_page(struct address_space *mapping, struct page *newpage, 168 struct page *page, enum migrate_mode mode); 169 #else 170 #define iomap_migrate_page NULL 171 #endif 172 int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, 173 const struct iomap_ops *ops); 174 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, 175 bool *did_zero, const struct iomap_ops *ops); 176 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, 177 const struct iomap_ops *ops); 178 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, 179 const struct iomap_ops *ops); 180 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 181 loff_t start, loff_t len, const struct iomap_ops *ops); 182 loff_t iomap_seek_hole(struct inode *inode, loff_t offset, 183 const struct iomap_ops *ops); 184 loff_t iomap_seek_data(struct inode *inode, loff_t offset, 185 const struct iomap_ops *ops); 186 sector_t iomap_bmap(struct address_space *mapping, sector_t bno, 187 const struct iomap_ops *ops); 188 189 /* 190 * Structure for writeback I/O completions. 191 */ 192 struct iomap_ioend { 193 struct list_head io_list; /* next ioend in chain */ 194 u16 io_type; 195 u16 io_flags; /* IOMAP_F_* */ 196 struct inode *io_inode; /* file being written to */ 197 size_t io_size; /* size of the extent */ 198 loff_t io_offset; /* offset in the file */ 199 void *io_private; /* file system private data */ 200 struct bio *io_bio; /* bio being built */ 201 struct bio io_inline_bio; /* MUST BE LAST! */ 202 }; 203 204 struct iomap_writeback_ops { 205 /* 206 * Required, maps the blocks so that writeback can be performed on 207 * the range starting at offset. 208 */ 209 int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode, 210 loff_t offset); 211 212 /* 213 * Optional, allows the file systems to perform actions just before 214 * submitting the bio and/or override the bio end_io handler for complex 215 * operations like copy on write extent manipulation or unwritten extent 216 * conversions. 217 */ 218 int (*prepare_ioend)(struct iomap_ioend *ioend, int status); 219 220 /* 221 * Optional, allows the file system to discard state on a page where 222 * we failed to submit any I/O. 223 */ 224 void (*discard_page)(struct page *page); 225 }; 226 227 struct iomap_writepage_ctx { 228 struct iomap iomap; 229 struct iomap_ioend *ioend; 230 const struct iomap_writeback_ops *ops; 231 }; 232 233 void iomap_finish_ioends(struct iomap_ioend *ioend, int error); 234 void iomap_ioend_try_merge(struct iomap_ioend *ioend, 235 struct list_head *more_ioends, 236 void (*merge_private)(struct iomap_ioend *ioend, 237 struct iomap_ioend *next)); 238 void iomap_sort_ioends(struct list_head *ioend_list); 239 int iomap_writepage(struct page *page, struct writeback_control *wbc, 240 struct iomap_writepage_ctx *wpc, 241 const struct iomap_writeback_ops *ops); 242 int iomap_writepages(struct address_space *mapping, 243 struct writeback_control *wbc, struct iomap_writepage_ctx *wpc, 244 const struct iomap_writeback_ops *ops); 245 246 /* 247 * Flags for direct I/O ->end_io: 248 */ 249 #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */ 250 #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */ 251 252 struct iomap_dio_ops { 253 int (*end_io)(struct kiocb *iocb, ssize_t size, int error, 254 unsigned flags); 255 }; 256 257 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, 258 const struct iomap_ops *ops, const struct iomap_dio_ops *dops, 259 bool wait_for_completion); 260 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin); 261 262 #ifdef CONFIG_SWAP 263 struct file; 264 struct swap_info_struct; 265 266 int iomap_swapfile_activate(struct swap_info_struct *sis, 267 struct file *swap_file, sector_t *pagespan, 268 const struct iomap_ops *ops); 269 #else 270 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO) 271 #endif /* CONFIG_SWAP */ 272 273 #endif /* LINUX_IOMAP_H */ 274