include/linux/iomap.h

   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 */