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 all iomap mappings:
  23  */
  24 #define IOMAP_F_NEW     0x01    /* blocks have been newly allocated */
  25
  26 /*
  27  * Flags that only need to be reported for IOMAP_REPORT requests:
  28  */
  29 #define IOMAP_F_MERGED  0x10    /* contains multiple blocks/extents */
  30 #define IOMAP_F_SHARED  0x20    /* block shared with another file */
  31
  32 /*
  33  * Magic value for blkno:
  34  */
  35 #define IOMAP_NULL_BLOCK -1LL   /* blkno is not valid */
  36
  37 struct iomap {
  38         sector_t                blkno;  /* 1st sector of mapping, 512b units */
  39         loff_t                  offset; /* file offset of mapping, bytes */
  40         u64                     length; /* length of mapping, bytes */
  41         u16                     type;   /* type of mapping */
  42         u16                     flags;  /* flags for mapping */
  43         struct block_device     *bdev;  /* block device for I/O */
  44         struct dax_device       *dax_dev; /* dax_dev for dax operations */
  45 };
  46
  47 /*
  48  * Flags for iomap_begin / iomap_end.  No flag implies a read.
  49  */
  50 #define IOMAP_WRITE             (1 << 0) /* writing, must allocate blocks */
  51 #define IOMAP_ZERO              (1 << 1) /* zeroing operation, may skip holes */
  52 #define IOMAP_REPORT            (1 << 2) /* report extent status, e.g. FIEMAP */
  53 #define IOMAP_FAULT             (1 << 3) /* mapping for page fault */
  54 #define IOMAP_DIRECT            (1 << 4) /* direct I/O */
  55 #define IOMAP_NOWAIT            (1 << 5) /* Don't wait for writeback */
  56
  57 struct iomap_ops {
  58         /*
  59          * Return the existing mapping at pos, or reserve space starting at
  60          * pos for up to length, as long as we can do it as a single mapping.
  61          * The actual length is returned in iomap->length.
  62          */
  63         int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
  64                         unsigned flags, struct iomap *iomap);
  65
  66         /*
  67          * Commit and/or unreserve space previous allocated using iomap_begin.
  68          * Written indicates the length of the successful write operation which
  69          * needs to be commited, while the rest needs to be unreserved.
  70          * Written might be zero if no data was written.
  71          */
  72         int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
  73                         ssize_t written, unsigned flags, struct iomap *iomap);
  74 };
  75
  76 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
  77                 const struct iomap_ops *ops);
  78 int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
  79                 const struct iomap_ops *ops);
  80 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
  81                 bool *did_zero, const struct iomap_ops *ops);
  82 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
  83                 const struct iomap_ops *ops);
  84 int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops);
  85 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  86                 loff_t start, loff_t len, const struct iomap_ops *ops);
  87 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
  88                 const struct iomap_ops *ops);
  89 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
  90                 const struct iomap_ops *ops);
  91
  92 /*
  93  * Flags for direct I/O ->end_io:
  94  */
  95 #define IOMAP_DIO_UNWRITTEN     (1 << 0)        /* covers unwritten extent(s) */
  96 #define IOMAP_DIO_COW           (1 << 1)        /* covers COW extent(s) */
  97 typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
  98                 unsigned flags);
  99 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 100                 const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
 101
 102 #endif /* LINUX_IOMAP_H */