include/linux/iomap.h

   1 #ifndef LINUX_IOMAP_H
   2 #define LINUX_IOMAP_H 1
   3
   4 #include <linux/types.h>
   5
   6 struct fiemap_extent_info;
   7 struct inode;
   8 struct iov_iter;
   9 struct kiocb;
  10 struct vm_area_struct;
  11 struct vm_fault;
  12
  13 /*
  14  * Types of block ranges for iomap mappings:
  15  */
  16 #define IOMAP_HOLE      0x01    /* no blocks allocated, need allocation */
  17 #define IOMAP_DELALLOC  0x02    /* delayed allocation blocks */
  18 #define IOMAP_MAPPED    0x03    /* blocks allocated @blkno */
  19 #define IOMAP_UNWRITTEN 0x04    /* blocks allocated @blkno in unwritten state */
  20
  21 /*
  22  * Flags for iomap mappings:
  23  */
  24 #define IOMAP_F_MERGED  0x01    /* contains multiple blocks/extents */
  25
  26 /*
  27  * Magic value for blkno:
  28  */
  29 #define IOMAP_NULL_BLOCK -1LL   /* blkno is not valid */
  30
  31 struct iomap {
  32         sector_t                blkno;  /* 1st sector of mapping, 512b units */
  33         loff_t                  offset; /* file offset of mapping, bytes */
  34         u64                     length; /* length of mapping, bytes */
  35         u16                     type;   /* type of mapping */
  36         u16                     flags;  /* flags for mapping */
  37         struct block_device     *bdev;  /* block device for I/O */
  38 };
  39
  40 /*
  41  * Flags for iomap_begin / iomap_end.  No flag implies a read.
  42  */
  43 #define IOMAP_WRITE             (1 << 0)
  44 #define IOMAP_ZERO              (1 << 1)
  45
  46 struct iomap_ops {
  47         /*
  48          * Return the existing mapping at pos, or reserve space starting at
  49          * pos for up to length, as long as we can do it as a single mapping.
  50          * The actual length is returned in iomap->length.
  51          */
  52         int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
  53                         unsigned flags, struct iomap *iomap);
  54
  55         /*
  56          * Commit and/or unreserve space previous allocated using iomap_begin.
  57          * Written indicates the length of the successful write operation which
  58          * needs to be commited, while the rest needs to be unreserved.
  59          * Written might be zero if no data was written.
  60          */
  61         int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
  62                         ssize_t written, unsigned flags, struct iomap *iomap);
  63 };
  64
  65 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
  66                 struct iomap_ops *ops);
  67 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
  68                 bool *did_zero, struct iomap_ops *ops);
  69 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
  70                 struct iomap_ops *ops);
  71 int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
  72                 struct iomap_ops *ops);
  73 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  74                 loff_t start, loff_t len, struct iomap_ops *ops);
  75
  76 #endif /* LINUX_IOMAP_H */