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/types.h>
   6
   7 struct fiemap_extent_info;
   8 struct inode;
   9 struct iov_iter;
  10 struct kiocb;
  11 struct vm_area_struct;
  12 struct vm_fault;
  13
  14 /*
  15  * Types of block ranges for iomap mappings:
  16  */
  17 #define IOMAP_HOLE      0x01    /* no blocks allocated, need allocation */
  18 #define IOMAP_DELALLOC  0x02    /* delayed allocation blocks */
  19 #define IOMAP_MAPPED    0x03    /* blocks allocated at @addr */
  20 #define IOMAP_UNWRITTEN 0x04    /* blocks allocated at @addr in unwritten state */
  21
  22 /*
  23  * Flags for all iomap mappings:
  24  *
  25  * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
  26  * written data and requires fdatasync to commit them to persistent storage.
  27  */
  28 #define IOMAP_F_NEW             0x01    /* blocks have been newly allocated */
  29 #define IOMAP_F_BOUNDARY        0x02    /* mapping ends at metadata boundary */
  30 #define IOMAP_F_DIRTY           0x04    /* uncommitted metadata */
  31
  32 /*
  33  * Flags that only need to be reported for IOMAP_REPORT requests:
  34  */
  35 #define IOMAP_F_MERGED          0x10    /* contains multiple blocks/extents */
  36 #define IOMAP_F_SHARED          0x20    /* block shared with another file */
  37 #define IOMAP_F_DATA_INLINE     0x40    /* data inline in the inode */
  38
  39 /*
  40  * Magic value for addr:
  41  */
  42 #define IOMAP_NULL_ADDR -1ULL   /* addr is not valid */
  43
  44 struct iomap {
  45         u64                     addr; /* disk offset of mapping, bytes */
  46         loff_t                  offset; /* file offset of mapping, bytes */
  47         u64                     length; /* length of mapping, bytes */
  48         u16                     type;   /* type of mapping */
  49         u16                     flags;  /* flags for mapping */
  50         struct block_device     *bdev;  /* block device for I/O */
  51         struct dax_device       *dax_dev; /* dax_dev for dax operations */
  52 };
  53
  54 /*
  55  * Flags for iomap_begin / iomap_end.  No flag implies a read.
  56  */
  57 #define IOMAP_WRITE             (1 << 0) /* writing, must allocate blocks */
  58 #define IOMAP_ZERO              (1 << 1) /* zeroing operation, may skip holes */
  59 #define IOMAP_REPORT            (1 << 2) /* report extent status, e.g. FIEMAP */
  60 #define IOMAP_FAULT             (1 << 3) /* mapping for page fault */
  61 #define IOMAP_DIRECT            (1 << 4) /* direct I/O */
  62 #define IOMAP_NOWAIT            (1 << 5) /* Don't wait for writeback */
  63
  64 struct iomap_ops {
  65         /*
  66          * Return the existing mapping at pos, or reserve space starting at
  67          * pos for up to length, as long as we can do it as a single mapping.
  68          * The actual length is returned in iomap->length.
  69          */
  70         int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
  71                         unsigned flags, struct iomap *iomap);
  72
  73         /*
  74          * Commit and/or unreserve space previous allocated using iomap_begin.
  75          * Written indicates the length of the successful write operation which
  76          * needs to be commited, while the rest needs to be unreserved.
  77          * Written might be zero if no data was written.
  78          */
  79         int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
  80                         ssize_t written, unsigned flags, struct iomap *iomap);
  81 };
  82
  83 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
  84                 const struct iomap_ops *ops);
  85 int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
  86                 const struct iomap_ops *ops);
  87 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
  88                 bool *did_zero, const struct iomap_ops *ops);
  89 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
  90                 const struct iomap_ops *ops);
  91 int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops);
  92 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  93                 loff_t start, loff_t len, const struct iomap_ops *ops);
  94 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
  95                 const struct iomap_ops *ops);
  96 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
  97                 const struct iomap_ops *ops);
  98
  99 /*
 100  * Flags for direct I/O ->end_io:
 101  */
 102 #define IOMAP_DIO_UNWRITTEN     (1 << 0)        /* covers unwritten extent(s) */
 103 #define IOMAP_DIO_COW           (1 << 1)        /* covers COW extent(s) */
 104 typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
 105                 unsigned flags);
 106 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 107                 const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
 108
 109 #endif /* LINUX_IOMAP_H */