fs/xfs/xfs_iomap.h

   1 /*
   2  * Copyright (c) 2003-2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_IOMAP_H__
  19 #define __XFS_IOMAP_H__
  20
  21 #define IOMAP_DADDR_NULL ((xfs_daddr_t) (-1LL))
  22
  23
  24 typedef enum {                          /* iomap_flags values */
  25         IOMAP_READ =            0,      /* mapping for a read */
  26         IOMAP_HOLE =            0x02,   /* mapping covers a hole  */
  27         IOMAP_DELAY =           0x04,   /* mapping covers delalloc region  */
  28         IOMAP_UNWRITTEN =       0x20,   /* mapping covers allocated */
  29                                         /* but uninitialized file data  */
  30         IOMAP_NEW =             0x40    /* just allocate */
  31 } iomap_flags_t;
  32
  33 typedef enum {
  34         /* base extent manipulation calls */
  35         BMAPI_READ = (1 << 0),          /* read extents */
  36         BMAPI_WRITE = (1 << 1),         /* create extents */
  37         BMAPI_ALLOCATE = (1 << 2),      /* delayed allocate to real extents */
  38         /* modifiers */
  39         BMAPI_IGNSTATE = (1 << 4),      /* ignore unwritten state on read */
  40         BMAPI_DIRECT = (1 << 5),        /* direct instead of buffered write */
  41         BMAPI_MMAP = (1 << 6),          /* allocate for mmap write */
  42         BMAPI_TRYLOCK = (1 << 7),       /* non-blocking request */
  43 } bmapi_flags_t;
  44
  45 #define BMAPI_FLAGS \
  46         { BMAPI_READ,           "READ" }, \
  47         { BMAPI_WRITE,          "WRITE" }, \
  48         { BMAPI_ALLOCATE,       "ALLOCATE" }, \
  49         { BMAPI_IGNSTATE,       "IGNSTATE" }, \
  50         { BMAPI_DIRECT,         "DIRECT" }, \
  51         { BMAPI_MMAP,           "MMAP" }, \
  52         { BMAPI_TRYLOCK,        "TRYLOCK" }
  53
  54 /*
  55  * xfs_iomap_t:  File system I/O map
  56  *
  57  * The iomap_bn field is expressed in 512-byte blocks, and is where the
  58  * mapping starts on disk.
  59  *
  60  * The iomap_offset, iomap_bsize and iomap_delta fields are in bytes.
  61  * iomap_offset is the offset of the mapping in the file itself.
  62  * iomap_bsize is the size of the mapping,  iomap_delta is the
  63  * desired data's offset into the mapping, given the offset supplied
  64  * to the file I/O map routine.
  65  *
  66  * When a request is made to read beyond the logical end of the object,
  67  * iomap_size may be set to 0, but iomap_offset and iomap_length should be set
  68  * to the actual amount of underlying storage that has been allocated, if any.
  69  */
  70
  71 typedef struct xfs_iomap {
  72         xfs_daddr_t             iomap_bn;       /* first 512B blk of mapping */
  73         xfs_off_t               iomap_offset;   /* offset of mapping, bytes */
  74         xfs_off_t               iomap_bsize;    /* size of mapping, bytes */
  75         xfs_off_t               iomap_delta;    /* offset into mapping, bytes */
  76         iomap_flags_t           iomap_flags;
  77 } xfs_iomap_t;
  78
  79 struct xfs_inode;
  80 struct xfs_bmbt_irec;
  81
  82 extern int xfs_iomap(struct xfs_inode *, xfs_off_t, ssize_t, int,
  83                      struct xfs_iomap *, int *);
  84 extern int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
  85                                   int, struct xfs_bmbt_irec *, int *, int);
  86 extern int xfs_iomap_write_delay(struct xfs_inode *, xfs_off_t, size_t, int,
  87                                  struct xfs_bmbt_irec *, int *);
  88 extern int xfs_iomap_write_allocate(struct xfs_inode *, xfs_off_t, size_t,
  89                                 struct xfs_bmbt_irec *, int *);
  90 extern int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, size_t);
  91
  92 #endif /* __XFS_IOMAP_H__*/