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