xref: /linux/fs/xfs/xfs_iomap.h (revision 776cfebb430c7b22c208b1b17add97f354d97cab)
1 /*
2  * Copyright (c) 2003-2005 Silicon Graphics, Inc.  All Rights Reserved.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of version 2 of the GNU General Public License as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it would be useful, but
9  * WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
11  *
12  * Further, this software is distributed without any warranty that it is
13  * free of the rightful claim of any third person regarding infringement
14  * or the like.  Any license provided herein, whether implied or
15  * otherwise, applies only to this software file.  Patent licenses, if
16  * any, provided herein do not apply to combinations of this program with
17  * other software, or any other product whatsoever.
18  *
19  * You should have received a copy of the GNU General Public License along
20  * with this program; if not, write the Free Software Foundation, Inc., 59
21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
22  *
23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
24  * Mountain View, CA  94043, or:
25  *
26  * http://www.sgi.com
27  *
28  * For further information regarding this notice, see:
29  *
30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
31  */
32 #ifndef __XFS_IOMAP_H__
33 #define __XFS_IOMAP_H__
34 
35 #define IOMAP_DADDR_NULL ((xfs_daddr_t) (-1LL))
36 
37 
38 typedef enum {				/* iomap_flags values */
39 	IOMAP_EOF =		0x01,	/* mapping contains EOF   */
40 	IOMAP_HOLE =		0x02,	/* mapping covers a hole  */
41 	IOMAP_DELAY =		0x04,	/* mapping covers delalloc region  */
42 	IOMAP_REALTIME =	0x10,	/* mapping on the realtime device  */
43 	IOMAP_UNWRITTEN =	0x20,	/* mapping covers allocated */
44 					/* but uninitialized file data  */
45 	IOMAP_NEW =		0x40	/* just allocate */
46 } iomap_flags_t;
47 
48 typedef enum {
49 	/* base extent manipulation calls */
50 	BMAPI_READ = (1 << 0),		/* read extents */
51 	BMAPI_WRITE = (1 << 1),		/* create extents */
52 	BMAPI_ALLOCATE = (1 << 2),	/* delayed allocate to real extents */
53 	BMAPI_UNWRITTEN  = (1 << 3),	/* unwritten extents to real extents */
54 	/* modifiers */
55 	BMAPI_IGNSTATE = (1 << 4),	/* ignore unwritten state on read */
56 	BMAPI_DIRECT = (1 << 5),	/* direct instead of buffered write */
57 	BMAPI_MMAP = (1 << 6),		/* allocate for mmap write */
58 	BMAPI_SYNC = (1 << 7),		/* sync write to flush delalloc space */
59 	BMAPI_TRYLOCK = (1 << 8),	/* non-blocking request */
60 	BMAPI_DEVICE = (1 << 9),	/* we only want to know the device */
61 } bmapi_flags_t;
62 
63 
64 /*
65  * xfs_iomap_t:  File system I/O map
66  *
67  * The iomap_bn field is expressed in 512-byte blocks, and is where the
68  * mapping starts on disk.
69  *
70  * The iomap_offset, iomap_bsize and iomap_delta fields are in bytes.
71  * iomap_offset is the offset of the mapping in the file itself.
72  * iomap_bsize is the size of the mapping,  iomap_delta is the
73  * desired data's offset into the mapping, given the offset supplied
74  * to the file I/O map routine.
75  *
76  * When a request is made to read beyond the logical end of the object,
77  * iomap_size may be set to 0, but iomap_offset and iomap_length should be set
78  * to the actual amount of underlying storage that has been allocated, if any.
79  */
80 
81 typedef struct xfs_iomap {
82 	xfs_daddr_t		iomap_bn;	/* first 512b blk of mapping */
83 	xfs_buftarg_t		*iomap_target;
84 	xfs_off_t		iomap_offset;	/* offset of mapping, bytes */
85 	xfs_off_t		iomap_bsize;	/* size of mapping, bytes */
86 	size_t			iomap_delta;	/* offset into mapping, bytes */
87 	iomap_flags_t		iomap_flags;
88 } xfs_iomap_t;
89 
90 struct xfs_iocore;
91 struct xfs_inode;
92 struct xfs_bmbt_irec;
93 
94 extern int xfs_iomap(struct xfs_iocore *, xfs_off_t, ssize_t, int,
95 		     struct xfs_iomap *, int *);
96 extern int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
97 				  int, struct xfs_bmbt_irec *, int *, int);
98 extern int xfs_iomap_write_delay(struct xfs_inode *, xfs_off_t, size_t, int,
99 				 struct xfs_bmbt_irec *, int *);
100 extern int xfs_iomap_write_allocate(struct xfs_inode *, xfs_off_t, size_t,
101 				struct xfs_bmbt_irec *, int *);
102 extern int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, size_t);
103 
104 #endif /* __XFS_IOMAP_H__*/
105