LXR linux/include/linux/iomap.h

   1#ifndef LINUX_IOMAP_H
   2#define LINUX_IOMAP_H 1
   3
   4#include <linux/types.h>
   5
   6struct fiemap_extent_info;
   7struct inode;
   8struct iov_iter;
   9struct kiocb;
  10struct vm_area_struct;
  11struct 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
  37struct 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
  57struct 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
  76ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
  77                const struct iomap_ops *ops);
  78int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
  79                const struct iomap_ops *ops);
  80int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,
  81                bool *did_zero, const struct iomap_ops *ops);
  82int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
  83                const struct iomap_ops *ops);
  84int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops);
  85int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
  86                loff_t start, loff_t len, const struct iomap_ops *ops);
  87loff_t iomap_seek_hole(struct inode *inode, loff_t offset,
  88                const struct iomap_ops *ops);
  89loff_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) */
  97typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
  98                unsigned flags);
  99ssize_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 */
 103