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