root/fs/xfs/xfs_iomap.h

INCLUDED FROM

/*
 * Copyright (c) 2003-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_IOMAP_H__
#define __XFS_IOMAP_H__

#define IOMAP_DADDR_NULL ((xfs_daddr_t) (-1LL))


typedef enum {                          /* iomap_flags values */
        IOMAP_READ =            0,      /* mapping for a read */
        IOMAP_HOLE =            0x02,   /* mapping covers a hole  */
        IOMAP_DELAY =           0x04,   /* mapping covers delalloc region  */
        IOMAP_REALTIME =        0x10,   /* mapping on the realtime device  */
        IOMAP_UNWRITTEN =       0x20,   /* mapping covers allocated */
                                        /* but uninitialized file data  */
        IOMAP_NEW =             0x40    /* just allocate */
} iomap_flags_t;

typedef enum {
        /* base extent manipulation calls */
        BMAPI_READ = (1 << 0),          /* read extents */
        BMAPI_WRITE = (1 << 1),         /* create extents */
        BMAPI_ALLOCATE = (1 << 2),      /* delayed allocate to real extents */
        /* modifiers */
        BMAPI_IGNSTATE = (1 << 4),      /* ignore unwritten state on read */
        BMAPI_DIRECT = (1 << 5),        /* direct instead of buffered write */
        BMAPI_MMAP = (1 << 6),          /* allocate for mmap write */
        BMAPI_SYNC = (1 << 7),          /* sync write to flush delalloc space */
        BMAPI_TRYLOCK = (1 << 8),       /* non-blocking request */
} bmapi_flags_t;


/*
 * xfs_iomap_t:  File system I/O map
 *
 * The iomap_bn field is expressed in 512-byte blocks, and is where the
 * mapping starts on disk.
 *
 * The iomap_offset, iomap_bsize and iomap_delta fields are in bytes.
 * iomap_offset is the offset of the mapping in the file itself.
 * iomap_bsize is the size of the mapping,  iomap_delta is the
 * desired data's offset into the mapping, given the offset supplied
 * to the file I/O map routine.
 *
 * When a request is made to read beyond the logical end of the object,
 * iomap_size may be set to 0, but iomap_offset and iomap_length should be set
 * to the actual amount of underlying storage that has been allocated, if any.
 */

typedef struct xfs_iomap {
        xfs_daddr_t             iomap_bn;       /* first 512b blk of mapping */
        xfs_buftarg_t           *iomap_target;
        xfs_off_t               iomap_offset;   /* offset of mapping, bytes */
        xfs_off_t               iomap_bsize;    /* size of mapping, bytes */
        xfs_off_t               iomap_delta;    /* offset into mapping, bytes */
        iomap_flags_t           iomap_flags;
} xfs_iomap_t;

struct xfs_inode;
struct xfs_bmbt_irec;

extern int xfs_iomap(struct xfs_inode *, xfs_off_t, ssize_t, int,
                     struct xfs_iomap *, int *);
extern int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
                                  int, struct xfs_bmbt_irec *, int *, int);
extern int xfs_iomap_write_delay(struct xfs_inode *, xfs_off_t, size_t, int,
                                 struct xfs_bmbt_irec *, int *);
extern int xfs_iomap_write_allocate(struct xfs_inode *, xfs_off_t, size_t,
                                struct xfs_bmbt_irec *, int *);
extern int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, size_t);

#endif /* __XFS_IOMAP_H__*/