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  * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
  27  * written data and requires fdatasync to commit them to persistent storage.
  28  */
  29 #define IOMAP_F_DIRTY   0x02
  30
  31 /*
  32  * Flags that only need to be reported for IOMAP_REPORT requests:
  33  */
  34 #define IOMAP_F_MERGED  0x10    /* contains multiple blocks/extents */
  35 #define IOMAP_F_SHARED  0x20    /* block shared with another file */
  36
  37 /*
  38  * Magic value for blkno:
  39  */
  40 #define IOMAP_NULL_BLOCK -1LL   /* blkno is not valid */
  41
  42 struct iomap {
  43         sector_t                blkno;  /* 1st sector of mapping, 512b units */
  44         loff_t                  offset; /* file offset of mapping, bytes */
  45         u64                     length; /* length of mapping, bytes */
  46         u16                     type;   /* type of mapping */
  47         u16                     flags;  /* flags for mapping */
  48         struct block_device     *bdev;  /* block device for I/O */
  49         struct dax_device       *dax_dev; /* dax_dev for dax operations */
  50 };
  51
  52 /*
  53  * Flags for iomap_begin / iomap_end.  No flag implies a read.
  54  */
  55 #define IOMAP_WRITE             (1 << 0) /* writing, must allocate blocks */
  56 #define IOMAP_ZERO              (1 << 1) /* zeroing operation, may skip holes */
  57 #define IOMAP_REPORT            (1 << 2) /* report extent status, e.g. FIEMAP */
  58 #define IOMAP_FAULT             (1 << 3) /* mapping for page fault */
  59 #define IOMAP_DIRECT            (1 << 4) /* direct I/O */
  60 #define IOMAP_NOWAIT            (1 << 5) /* Don't wait for writeback */
  61
  62 struct iomap_ops {
  63         /*
  64          * Return the existing mapping at pos, or reserve space starting at
  65          * pos for up to length, as long as we can do it as a single mapping.
  66          * The actual length is returned in iomap->length.
  67          */
  68         int (*iomap_begin)(struct inode *inode, loff_t pos, loff_t length,
  69                         unsigned flags, struct iomap *iomap);
  70
  71         /*
  72          * Commit and/or unreserve space previous allocated using iomap_begin.
  73          * Written indicates the length of the successful write operation which
  74          * needs to be commited, while the rest needs to be unreserved.
  75          * Written might be zero if no data was written.
  76          */
  77         int (*iomap_end)(struct inode *inode, loff_t pos, loff_t length,
  78                         ssize_t written, unsigned flags, struct iomap *iomap);
  79 };
  80
  81 ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
  82                 const struct iomap_ops *ops);
  83 int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
  84                 const struct iomap_ops *ops);
  85 int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
  86                 bool *did_zero, const struct iomap_ops *ops);
  87 int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
  88                 const struct iomap_ops *ops);
  89 int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops);
  90 int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  91                 loff_t start, loff_t len, const struct iomap_ops *ops);
  92 loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
  93                 const struct iomap_ops *ops);
  94 loff_t iomap_seek_data(struct inode *inode, loff_t offset,
  95                 const struct iomap_ops *ops);
  96
  97 /*
  98  * Flags for direct I/O ->end_io:
  99  */
 100 #define IOMAP_DIO_UNWRITTEN     (1 << 0)        /* covers unwritten extent(s) */
 101 #define IOMAP_DIO_COW           (1 << 1)        /* covers COW extent(s) */
 102 typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
 103                 unsigned flags);
 104 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 105                 const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
 106
 107 #endif /* LINUX_IOMAP_H */