xref: /openbmc/linux/fs/xfs/xfs_iomap.h (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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_EOF =		0x01,	/* mapping contains EOF   */
27 	IOMAP_HOLE =		0x02,	/* mapping covers a hole  */
28 	IOMAP_DELAY =		0x04,	/* mapping covers delalloc region  */
29 	IOMAP_REALTIME =	0x10,	/* mapping on the realtime device  */
30 	IOMAP_UNWRITTEN =	0x20,	/* mapping covers allocated */
31 					/* but uninitialized file data  */
32 	IOMAP_NEW =		0x40	/* just allocate */
33 } iomap_flags_t;
34 
35 typedef enum {
36 	/* base extent manipulation calls */
37 	BMAPI_READ = (1 << 0),		/* read extents */
38 	BMAPI_WRITE = (1 << 1),		/* create extents */
39 	BMAPI_ALLOCATE = (1 << 2),	/* delayed allocate to real extents */
40 	BMAPI_UNWRITTEN  = (1 << 3),	/* unwritten extents to real extents */
41 	/* modifiers */
42 	BMAPI_IGNSTATE = (1 << 4),	/* ignore unwritten state on read */
43 	BMAPI_DIRECT = (1 << 5),	/* direct instead of buffered write */
44 	BMAPI_MMAP = (1 << 6),		/* allocate for mmap write */
45 	BMAPI_SYNC = (1 << 7),		/* sync write to flush delalloc space */
46 	BMAPI_TRYLOCK = (1 << 8),	/* non-blocking request */
47 	BMAPI_DEVICE = (1 << 9),	/* we only want to know the device */
48 } bmapi_flags_t;
49 
50 
51 /*
52  * xfs_iomap_t:  File system I/O map
53  *
54  * The iomap_bn field is expressed in 512-byte blocks, and is where the
55  * mapping starts on disk.
56  *
57  * The iomap_offset, iomap_bsize and iomap_delta fields are in bytes.
58  * iomap_offset is the offset of the mapping in the file itself.
59  * iomap_bsize is the size of the mapping,  iomap_delta is the
60  * desired data's offset into the mapping, given the offset supplied
61  * to the file I/O map routine.
62  *
63  * When a request is made to read beyond the logical end of the object,
64  * iomap_size may be set to 0, but iomap_offset and iomap_length should be set
65  * to the actual amount of underlying storage that has been allocated, if any.
66  */
67 
68 typedef struct xfs_iomap {
69 	xfs_daddr_t		iomap_bn;	/* first 512b blk of mapping */
70 	xfs_buftarg_t		*iomap_target;
71 	xfs_off_t		iomap_offset;	/* offset of mapping, bytes */
72 	xfs_off_t		iomap_bsize;	/* size of mapping, bytes */
73 	xfs_off_t		iomap_delta;	/* offset into mapping, bytes */
74 	iomap_flags_t		iomap_flags;
75 } xfs_iomap_t;
76 
77 struct xfs_iocore;
78 struct xfs_inode;
79 struct xfs_bmbt_irec;
80 
81 extern int xfs_iomap(struct xfs_iocore *, xfs_off_t, ssize_t, int,
82 		     struct xfs_iomap *, int *);
83 extern int xfs_iomap_write_direct(struct xfs_inode *, xfs_off_t, size_t,
84 				  int, struct xfs_bmbt_irec *, int *, int);
85 extern int xfs_iomap_write_delay(struct xfs_inode *, xfs_off_t, size_t, int,
86 				 struct xfs_bmbt_irec *, int *);
87 extern int xfs_iomap_write_allocate(struct xfs_inode *, xfs_off_t, size_t,
88 				struct xfs_bmbt_irec *, int *);
89 extern int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, size_t);
90 
91 #endif /* __XFS_IOMAP_H__*/
92