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_dio;
  17 struct iomap_writepage_ctx;
  18 struct iov_iter;
  19 struct kiocb;
  20 struct page;
  21 struct vm_area_struct;
  22 struct vm_fault;
  23
  24 /*
  25  * Types of block ranges for iomap mappings:
  26  */
  27 #define IOMAP_HOLE      0       /* no blocks allocated, need allocation */
  28 #define IOMAP_DELALLOC  1       /* delayed allocation blocks */
  29 #define IOMAP_MAPPED    2       /* blocks allocated at @addr */
  30 #define IOMAP_UNWRITTEN 3       /* blocks allocated at @addr in unwritten state */
  31 #define IOMAP_INLINE    4       /* data inline in the inode */
  32
  33 /*
  34  * Flags reported by the file system from iomap_begin:
  35  *
  36  * IOMAP_F_NEW indicates that the blocks have been newly allocated and need
  37  * zeroing for areas that no data is copied to.
  38  *
  39  * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
  40  * written data and requires fdatasync to commit them to persistent storage.
  41  * This needs to take into account metadata changes that *may* be made at IO
  42  * completion, such as file size updates from direct IO.
  43  *
  44  * IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
  45  * unshared as part a write.
  46  *
  47  * IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
  48  * mappings.
  49  *
  50  * IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
  51  * buffer heads for this mapping.
  52  */
  53 #define IOMAP_F_NEW             0x01
  54 #define IOMAP_F_DIRTY           0x02
  55 #define IOMAP_F_SHARED          0x04
  56 #define IOMAP_F_MERGED          0x08
  57 #define IOMAP_F_BUFFER_HEAD     0x10
  58 #define IOMAP_F_ZONE_APPEND     0x20
  59
  60 /*
  61  * Flags set by the core iomap code during operations:
  62  *
  63  * IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
  64  * has changed as the result of this write operation.
  65  */
  66 #define IOMAP_F_SIZE_CHANGED    0x100
  67
  68 /*
  69  * Flags from 0x1000 up are for file system specific usage:
  70  */
  71 #define IOMAP_F_PRIVATE         0x1000
  72
  73
  74 /*
  75  * Magic value for addr:
  76  */
  77 #define IOMAP_NULL_ADDR -1ULL   /* addr is not valid */
  78
  79 struct iomap_page_ops;
  80
  81 struct iomap {
  82         u64                     addr; /* disk offset of mapping, bytes */
  83         loff_t                  offset; /* file offset of mapping, bytes */
  84         u64                     length; /* length of mapping, bytes */
  85         u16                     type;   /* type of mapping */
  86         u16                     flags;  /* flags for mapping */
  87         struct block_device     *bdev;  /* block device for I/O */
  88         struct dax_device       *dax_dev; /* dax_dev for dax operations */
  89         void                    *inline_data;
  90         void                    *private; /* filesystem private */
  91         const struct iomap_page_ops *page_ops;
  92 };
  93
  94 static inline sector_t
  95 iomap_sector(struct iomap *iomap, loff_t pos)
  96 {
  97         return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT;
  98 }
  99
 100 /*
 101  * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare
 102  * and page_done will be called for each page written to.  This only applies to
 103  * buffered writes as unbuffered writes will not typically have pages
 104  * associated with them.
 105  *
 106  * When page_prepare succeeds, page_done will always be called to do any
 107  * cleanup work necessary.  In that page_done call, @page will be NULL if the
 108  * associated page could not be obtained.
 109  */
 110 struct iomap_page_ops {
 111         int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len,
 112                         struct iomap *iomap);
 113         void (*page_done)(struct inode *inode, loff_t pos, unsigned copied,
 114                         struct page *page, struct iomap *iomap);
 115 };
 116
 117 /*
 118  * Flags for iomap_begin / iomap_end.  No flag implies a read.
 119  */
 120 #define IOMAP_WRITE             (1 << 0) /* writing, must allocate blocks */
 121 #define IOMAP_ZERO              (1 << 1) /* zeroing operation, may skip holes */
 122 #define IOMAP_REPORT            (1 << 2) /* report extent status, e.g. FIEMAP */
 123 #define IOMAP_FAULT             (1 << 3) /* mapping for page fault */
 124 #define IOMAP_DIRECT            (1 << 4) /* direct I/O */
 125 #define IOMAP_NOWAIT            (1 << 5) /* do not block */
 126 #define IOMAP_OVERWRITE_ONLY    (1 << 6) /* only pure overwrites allowed */
 127
 128 struct iomap_ops {
 129         /*
 130          * Return the existing mapping at pos, or reserve space starting at
 131          * pos for up to length, as long as we can do it as a single mapping.
 132          * The actual length is returned in iomap->length.
 133          */
 134         int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
 135                         unsigned flags, struct iomap *iomap,
 136                         struct iomap *srcmap);
 137
 138         /*
 139          * Commit and/or unreserve space previous allocated using iomap_begin.
 140          * Written indicates the length of the successful write operation which
 141          * needs to be commited, while the rest needs to be unreserved.
 142          * Written might be zero if no data was written.
 143          */
 144         int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
 145                         ssize_t written, unsigned flags, struct iomap *iomap);
 146 };
 147
 148 /*
 149  * Main iomap iterator function.
 150  */
 151 typedef loff_t (*iomap_actor_t)(struct inode *inode, loff_t pos, loff_t len,
 152                 void *data, struct iomap *iomap, struct iomap *srcmap);
 153
 154 loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
 155                 unsigned flags, const struct iomap_ops *ops, void *data,
 156                 iomap_actor_t actor);
 157
 158 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
 159                 const struct iomap_ops *ops);
 160 int iomap_readpage(struct page *page, const struct iomap_ops *ops);
 161 void iomap_readahead(struct readahead_control *, const struct iomap_ops *ops);
 162 int iomap_is_partially_uptodate(struct page *page, unsigned long from,
 163                 unsigned long count);
 164 int iomap_releasepage(struct page *page, gfp_t gfp_mask);
 165 void iomap_invalidatepage(struct page *page, unsigned int offset,
 166                 unsigned int len);
 167 #ifdef CONFIG_MIGRATION
 168 int iomap_migrate_page(struct address_space *mapping, struct page *newpage,
 169                 struct page *page, enum migrate_mode mode);
 170 #else
 171 #define iomap_migrate_page NULL
 172 #endif
 173 int iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
 174                 const struct iomap_ops *ops);
 175 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
 176                 bool *did_zero, const struct iomap_ops *ops);
 177 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
 178                 const struct iomap_ops *ops);
 179 vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf,
 180                         const struct iomap_ops *ops);
 181 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 182                 u64 start, u64 len, const struct iomap_ops *ops);
 183 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
 184                 const struct iomap_ops *ops);
 185 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
 186                 const struct iomap_ops *ops);
 187 sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
 188                 const struct iomap_ops *ops);
 189
 190 /*
 191  * Structure for writeback I/O completions.
 192  */
 193 struct iomap_ioend {
 194         struct list_head        io_list;        /* next ioend in chain */
 195         u16                     io_type;
 196         u16                     io_flags;       /* IOMAP_F_* */
 197         struct inode            *io_inode;      /* file being written to */
 198         size_t                  io_size;        /* size of the extent */
 199         loff_t                  io_offset;      /* offset in the file */
 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, loff_t fileoff);
 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 iomap_sort_ioends(struct list_head *ioend_list);
 237 int iomap_writepage(struct page *page, struct writeback_control *wbc,
 238                 struct iomap_writepage_ctx *wpc,
 239                 const struct iomap_writeback_ops *ops);
 240 int iomap_writepages(struct address_space *mapping,
 241                 struct writeback_control *wbc, struct iomap_writepage_ctx *wpc,
 242                 const struct iomap_writeback_ops *ops);
 243
 244 /*
 245  * Flags for direct I/O ->end_io:
 246  */
 247 #define IOMAP_DIO_UNWRITTEN     (1 << 0)        /* covers unwritten extent(s) */
 248 #define IOMAP_DIO_COW           (1 << 1)        /* covers COW extent(s) */
 249
 250 struct iomap_dio_ops {
 251         int (*end_io)(struct kiocb *iocb, ssize_t size, int error,
 252                       unsigned flags);
 253         blk_qc_t (*submit_io)(struct inode *inode, struct iomap *iomap,
 254                         struct bio *bio, loff_t file_offset);
 255 };
 256
 257 /*
 258  * Wait for the I/O to complete in iomap_dio_rw even if the kiocb is not
 259  * synchronous.
 260  */
 261 #define IOMAP_DIO_FORCE_WAIT    (1 << 0)
 262
 263 /*
 264  * Do not allocate blocks or zero partial blocks, but instead fall back to
 265  * the caller by returning -EAGAIN.  Used to optimize direct I/O writes that
 266  * are not aligned to the file system block size.
 267   */
 268 #define IOMAP_DIO_OVERWRITE_ONLY        (1 << 1)
 269
 270 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 271                 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
 272                 unsigned int dio_flags);
 273 struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 274                 const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
 275                 unsigned int dio_flags);
 276 ssize_t iomap_dio_complete(struct iomap_dio *dio);
 277 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
 278
 279 #ifdef CONFIG_SWAP
 280 struct file;
 281 struct swap_info_struct;
 282
 283 int iomap_swapfile_activate(struct swap_info_struct *sis,
 284                 struct file *swap_file, sector_t *pagespan,
 285                 const struct iomap_ops *ops);
 286 #else
 287 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops)  (-EIO)
 288 #endif /* CONFIG_SWAP */
 289
 290 #endif /* LINUX_IOMAP_H */