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/mm.h> 8 #include <linux/types.h> 9 #include <linux/mm_types.h> 10 11 struct address_space; 12 struct fiemap_extent_info; 13 struct inode; 14 struct iov_iter; 15 struct kiocb; 16 struct page; 17 struct vm_area_struct; 18 struct vm_fault; 19 20 /* 21 * Types of block ranges for iomap mappings: 22 */ 23 #define IOMAP_HOLE 0x01 /* no blocks allocated, need allocation */ 24 #define IOMAP_DELALLOC 0x02 /* delayed allocation blocks */ 25 #define IOMAP_MAPPED 0x03 /* blocks allocated at @addr */ 26 #define IOMAP_UNWRITTEN 0x04 /* blocks allocated at @addr in unwritten state */ 27 #define IOMAP_INLINE 0x05 /* data inline in the inode */ 28 29 /* 30 * Flags for all iomap mappings: 31 * 32 * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access 33 * written data and requires fdatasync to commit them to persistent storage. 34 */ 35 #define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */ 36 #define IOMAP_F_DIRTY 0x02 /* uncommitted metadata */ 37 #define IOMAP_F_BUFFER_HEAD 0x04 /* file system requires buffer heads */ 38 #define IOMAP_F_SIZE_CHANGED 0x08 /* file size has changed */ 39 40 /* 41 * Flags that only need to be reported for IOMAP_REPORT requests: 42 */ 43 #define IOMAP_F_MERGED 0x10 /* contains multiple blocks/extents */ 44 #define IOMAP_F_SHARED 0x20 /* block shared with another file */ 45 46 /* 47 * Flags from 0x1000 up are for file system specific usage: 48 */ 49 #define IOMAP_F_PRIVATE 0x1000 50 51 52 /* 53 * Magic value for addr: 54 */ 55 #define IOMAP_NULL_ADDR -1ULL /* addr is not valid */ 56 57 struct iomap_page_ops; 58 59 struct iomap { 60 u64 addr; /* disk offset of mapping, bytes */ 61 loff_t offset; /* file offset of mapping, bytes */ 62 u64 length; /* length of mapping, bytes */ 63 u16 type; /* type of mapping */ 64 u16 flags; /* flags for mapping */ 65 struct block_device *bdev; /* block device for I/O */ 66 struct dax_device *dax_dev; /* dax_dev for dax operations */ 67 void *inline_data; 68 void *private; /* filesystem private */ 69 const struct iomap_page_ops *page_ops; 70 }; 71 72 /* 73 * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare 74 * and page_done will be called for each page written to. This only applies to 75 * buffered writes as unbuffered writes will not typically have pages 76 * associated with them. 77 * 78 * When page_prepare succeeds, page_done will always be called to do any 79 * cleanup work necessary. In that page_done call, @page will be NULL if the 80 * associated page could not be obtained. 81 */ 82 struct iomap_page_ops { 83 int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len, 84 struct iomap *iomap); 85 void (*page_done)(struct inode *inode, loff_t pos, unsigned copied, 86 struct page *page, struct iomap *iomap); 87 }; 88 89 /* 90 * Flags for iomap_begin / iomap_end. No flag implies a read. 91 */ 92 #define IOMAP_WRITE (1 << 0) /* writing, must allocate blocks */ 93 #define IOMAP_ZERO (1 << 1) /* zeroing operation, may skip holes */ 94 #define IOMAP_REPORT (1 << 2) /* report extent status, e.g. FIEMAP */ 95 #define IOMAP_FAULT (1 << 3) /* mapping for page fault */ 96 #define IOMAP_DIRECT (1 << 4) /* direct I/O */ 97 #define IOMAP_NOWAIT (1 << 5) /* do not block */ 98 99 struct iomap_ops { 100 /* 101 * Return the existing mapping at pos, or reserve space starting at 102 * pos for up to length, as long as we can do it as a single mapping. 103 * The actual length is returned in iomap->length. 104 */ 105 int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length, 106 unsigned flags, struct iomap *iomap); 107 108 /* 109 * Commit and/or unreserve space previous allocated using iomap_begin. 110 * Written indicates the length of the successful write operation which 111 * needs to be commited, while the rest needs to be unreserved. 112 * Written might be zero if no data was written. 113 */ 114 int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length, 115 ssize_t written, unsigned flags, struct iomap *iomap); 116 }; 117 118 /* 119 * Structure allocate for each page when block size < PAGE_SIZE to track 120 * sub-page uptodate status and I/O completions. 121 */ 122 struct iomap_page { 123 atomic_t read_count; 124 atomic_t write_count; 125 DECLARE_BITMAP(uptodate, PAGE_SIZE / 512); 126 }; 127 128 static inline struct iomap_page *to_iomap_page(struct page *page) 129 { 130 if (page_has_private(page)) 131 return (struct iomap_page *)page_private(page); 132 return NULL; 133 } 134 135 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, 136 const struct iomap_ops *ops); 137 int iomap_readpage(struct page *page, const struct iomap_ops *ops); 138 int iomap_readpages(struct address_space *mapping, struct list_head *pages, 139 unsigned nr_pages, const struct iomap_ops *ops); 140 int iomap_set_page_dirty(struct page *page); 141 int iomap_is_partially_uptodate(struct page *page, unsigned long from, 142 unsigned long count); 143 int iomap_releasepage(struct page *page, gfp_t gfp_mask); 144 void iomap_invalidatepage(struct page *page, unsigned int offset, 145 unsigned int len); 146 #ifdef CONFIG_MIGRATION 147 int iomap_migrate_page(struct address_space *mapping, struct page *newpage, 148 struct page *page, enum migrate_mode mode); 149 #else 150 #define iomap_migrate_page NULL 151 #endif 152 int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len, 153 const struct iomap_ops *ops); 154 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, 155 bool *did_zero, const struct iomap_ops *ops); 156 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, 157 const struct iomap_ops *ops); 158 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, 159 const struct iomap_ops *ops); 160 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 161 loff_t start, loff_t len, const struct iomap_ops *ops); 162 loff_t iomap_seek_hole(struct inode *inode, loff_t offset, 163 const struct iomap_ops *ops); 164 loff_t iomap_seek_data(struct inode *inode, loff_t offset, 165 const struct iomap_ops *ops); 166 sector_t iomap_bmap(struct address_space *mapping, sector_t bno, 167 const struct iomap_ops *ops); 168 169 /* 170 * Flags for direct I/O ->end_io: 171 */ 172 #define IOMAP_DIO_UNWRITTEN (1 << 0) /* covers unwritten extent(s) */ 173 #define IOMAP_DIO_COW (1 << 1) /* covers COW extent(s) */ 174 typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret, 175 unsigned flags); 176 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, 177 const struct iomap_ops *ops, iomap_dio_end_io_t end_io); 178 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin); 179 180 #ifdef CONFIG_SWAP 181 struct file; 182 struct swap_info_struct; 183 184 int iomap_swapfile_activate(struct swap_info_struct *sis, 185 struct file *swap_file, sector_t *pagespan, 186 const struct iomap_ops *ops); 187 #else 188 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops) (-EIO) 189 #endif /* CONFIG_SWAP */ 190 191 #endif /* LINUX_IOMAP_H */ 192