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_REALTIME =        0x10,   /* mapping on the realtime device  */
  29         IOMAP_UNWRITTEN =       0x20,   /* mapping covers allocated */
  30                                         /* but uninitialized file data  */
  31         IOMAP_NEW =             0x40    /* just allocate */
  32 } iomap_flags_t;
  33
  34 typedef enum {
  35         /* base extent manipulation calls */
  36         BMAPI_READ = (1 << 0),          /* read extents */
  37         BMAPI_WRITE = (1 << 1),         /* create extents */
  38         BMAPI_ALLOCATE = (1 << 2),      /* delayed allocate to real extents */
  39         /* modifiers */
  40         BMAPI_IGNSTATE = (1 << 4),      /* ignore unwritten state on read */
  41         BMAPI_DIRECT = (1 << 5),        /* direct instead of buffered write */
  42         BMAPI_MMAP = (1 << 6),          /* allocate for mmap write */
  43         BMAPI_TRYLOCK = (1 << 7),       /* non-blocking request */
  44 } bmapi_flags_t;
  45
  46
  47 /*
  48  * xfs_iomap_t:  File system I/O map
  49  *
  50  * The iomap_bn field is expressed in 512-byte blocks, and is where the
  51  * mapping starts on disk.
  52  *
  53  * The iomap_offset, iomap_bsize and iomap_delta fields are in bytes.
  54  * iomap_offset is the offset of the mapping in the file itself.
  55  * iomap_bsize is the size of the mapping,  iomap_delta is the
  56  * desired data's offset into the mapping, given the offset supplied
  57  * to the file I/O map routine.
  58  *
  59  * When a request is made to read beyond the logical end of the object,
  60  * iomap_size may be set to 0, but iomap_offset and iomap_length should be set
  61  * to the actual amount of underlying storage that has been allocated, if any.
  62  */
  63
  64 typedef struct xfs_iomap {
  65         xfs_daddr_t             iomap_bn;       /* first 512B blk of mapping */
  66         xfs_buftarg_t           *iomap_target;
  67         xfs_off_t               iomap_offset;   /* offset of mapping, bytes */
  68         xfs_off_t               iomap_bsize;    /* size of mapping, bytes */
  69         xfs_off_t               iomap_delta;    /* offset into mapping, bytes */
  70         iomap_flags_t           iomap_flags;
  71 } xfs_iomap_t;
  72
  73 struct xfs_inode;
  74 struct xfs_bmbt_irec;
  75
  76 extern int xfs_iomap(struct xfs_inode *, xfs_off_t, ssize_t, int,
  77                      struct xfs_iomap *, int *);
  78 extern int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
  79                                   int, struct xfs_bmbt_irec *, int *, int);
  80 extern int xfs_iomap_write_delay(struct xfs_inode *, xfs_off_t, size_t, int,
  81                                  struct xfs_bmbt_irec *, int *);
  82 extern int xfs_iomap_write_allocate(struct xfs_inode *, xfs_off_t, size_t,
  83                                 struct xfs_bmbt_irec *, int *);
  84 extern int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, size_t);
  85
  86 #endif /* __XFS_IOMAP_H__*/