xref: /linux/fs/xfs/xfs_iomap.h (revision bcefe12eff5dca6fdfa94ed85e5bee66380d5cd9)
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__*/
87