xref: /openbmc/linux/fs/xfs/libxfs/xfs_inode_fork.h (revision 9cfc5c90)
1 /*
2  * Copyright (c) 2000-2003,2005 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_INODE_FORK_H__
19 #define	__XFS_INODE_FORK_H__
20 
21 struct xfs_inode_log_item;
22 struct xfs_dinode;
23 
24 /*
25  * The following xfs_ext_irec_t struct introduces a second (top) level
26  * to the in-core extent allocation scheme. These structs are allocated
27  * in a contiguous block, creating an indirection array where each entry
28  * (irec) contains a pointer to a buffer of in-core extent records which
29  * it manages. Each extent buffer is 4k in size, since 4k is the system
30  * page size on Linux i386 and systems with larger page sizes don't seem
31  * to gain much, if anything, by using their native page size as the
32  * extent buffer size. Also, using 4k extent buffers everywhere provides
33  * a consistent interface for CXFS across different platforms.
34  *
35  * There is currently no limit on the number of irec's (extent lists)
36  * allowed, so heavily fragmented files may require an indirection array
37  * which spans multiple system pages of memory. The number of extents
38  * which would require this amount of contiguous memory is very large
39  * and should not cause problems in the foreseeable future. However,
40  * if the memory needed for the contiguous array ever becomes a problem,
41  * it is possible that a third level of indirection may be required.
42  */
43 typedef struct xfs_ext_irec {
44 	xfs_bmbt_rec_host_t *er_extbuf;	/* block of extent records */
45 	xfs_extnum_t	er_extoff;	/* extent offset in file */
46 	xfs_extnum_t	er_extcount;	/* number of extents in page/block */
47 } xfs_ext_irec_t;
48 
49 /*
50  * File incore extent information, present for each of data & attr forks.
51  */
52 #define	XFS_IEXT_BUFSZ		4096
53 #define	XFS_LINEAR_EXTS		(XFS_IEXT_BUFSZ / (uint)sizeof(xfs_bmbt_rec_t))
54 #define	XFS_INLINE_EXTS		2
55 #define	XFS_INLINE_DATA		32
56 typedef struct xfs_ifork {
57 	int			if_bytes;	/* bytes in if_u1 */
58 	int			if_real_bytes;	/* bytes allocated in if_u1 */
59 	struct xfs_btree_block	*if_broot;	/* file's incore btree root */
60 	short			if_broot_bytes;	/* bytes allocated for root */
61 	unsigned char		if_flags;	/* per-fork flags */
62 	union {
63 		xfs_bmbt_rec_host_t *if_extents;/* linear map file exts */
64 		xfs_ext_irec_t	*if_ext_irec;	/* irec map file exts */
65 		char		*if_data;	/* inline file data */
66 	} if_u1;
67 	union {
68 		xfs_bmbt_rec_host_t if_inline_ext[XFS_INLINE_EXTS];
69 						/* very small file extents */
70 		char		if_inline_data[XFS_INLINE_DATA];
71 						/* very small file data */
72 		xfs_dev_t	if_rdev;	/* dev number if special */
73 		uuid_t		if_uuid;	/* mount point value */
74 	} if_u2;
75 } xfs_ifork_t;
76 
77 /*
78  * Per-fork incore inode flags.
79  */
80 #define	XFS_IFINLINE	0x01	/* Inline data is read in */
81 #define	XFS_IFEXTENTS	0x02	/* All extent pointers are read in */
82 #define	XFS_IFBROOT	0x04	/* i_broot points to the bmap b-tree root */
83 #define	XFS_IFEXTIREC	0x08	/* Indirection array of extent blocks */
84 
85 /*
86  * Fork handling.
87  */
88 
89 #define XFS_IFORK_Q(ip)			((ip)->i_d.di_forkoff != 0)
90 #define XFS_IFORK_BOFF(ip)		((int)((ip)->i_d.di_forkoff << 3))
91 
92 #define XFS_IFORK_PTR(ip,w)		\
93 	((w) == XFS_DATA_FORK ? \
94 		&(ip)->i_df : \
95 		(ip)->i_afp)
96 #define XFS_IFORK_DSIZE(ip) \
97 	(XFS_IFORK_Q(ip) ? \
98 		XFS_IFORK_BOFF(ip) : \
99 		XFS_LITINO((ip)->i_mount, (ip)->i_d.di_version))
100 #define XFS_IFORK_ASIZE(ip) \
101 	(XFS_IFORK_Q(ip) ? \
102 		XFS_LITINO((ip)->i_mount, (ip)->i_d.di_version) - \
103 			XFS_IFORK_BOFF(ip) : \
104 		0)
105 #define XFS_IFORK_SIZE(ip,w) \
106 	((w) == XFS_DATA_FORK ? \
107 		XFS_IFORK_DSIZE(ip) : \
108 		XFS_IFORK_ASIZE(ip))
109 #define XFS_IFORK_FORMAT(ip,w) \
110 	((w) == XFS_DATA_FORK ? \
111 		(ip)->i_d.di_format : \
112 		(ip)->i_d.di_aformat)
113 #define XFS_IFORK_FMT_SET(ip,w,n) \
114 	((w) == XFS_DATA_FORK ? \
115 		((ip)->i_d.di_format = (n)) : \
116 		((ip)->i_d.di_aformat = (n)))
117 #define XFS_IFORK_NEXTENTS(ip,w) \
118 	((w) == XFS_DATA_FORK ? \
119 		(ip)->i_d.di_nextents : \
120 		(ip)->i_d.di_anextents)
121 #define XFS_IFORK_NEXT_SET(ip,w,n) \
122 	((w) == XFS_DATA_FORK ? \
123 		((ip)->i_d.di_nextents = (n)) : \
124 		((ip)->i_d.di_anextents = (n)))
125 #define XFS_IFORK_MAXEXT(ip, w) \
126 	(XFS_IFORK_SIZE(ip, w) / sizeof(xfs_bmbt_rec_t))
127 
128 int		xfs_iformat_fork(struct xfs_inode *, struct xfs_dinode *);
129 void		xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
130 				struct xfs_inode_log_item *, int);
131 void		xfs_idestroy_fork(struct xfs_inode *, int);
132 void		xfs_idata_realloc(struct xfs_inode *, int, int);
133 void		xfs_iroot_realloc(struct xfs_inode *, int, int);
134 int		xfs_iread_extents(struct xfs_trans *, struct xfs_inode *, int);
135 int		xfs_iextents_copy(struct xfs_inode *, struct xfs_bmbt_rec *,
136 				  int);
137 
138 struct xfs_bmbt_rec_host *
139 		xfs_iext_get_ext(struct xfs_ifork *, xfs_extnum_t);
140 void		xfs_iext_insert(struct xfs_inode *, xfs_extnum_t, xfs_extnum_t,
141 				struct xfs_bmbt_irec *, int);
142 void		xfs_iext_add(struct xfs_ifork *, xfs_extnum_t, int);
143 void		xfs_iext_add_indirect_multi(struct xfs_ifork *, int,
144 					    xfs_extnum_t, int);
145 void		xfs_iext_remove(struct xfs_inode *, xfs_extnum_t, int, int);
146 void		xfs_iext_remove_inline(struct xfs_ifork *, xfs_extnum_t, int);
147 void		xfs_iext_remove_direct(struct xfs_ifork *, xfs_extnum_t, int);
148 void		xfs_iext_remove_indirect(struct xfs_ifork *, xfs_extnum_t, int);
149 void		xfs_iext_realloc_direct(struct xfs_ifork *, int);
150 void		xfs_iext_direct_to_inline(struct xfs_ifork *, xfs_extnum_t);
151 void		xfs_iext_inline_to_direct(struct xfs_ifork *, int);
152 void		xfs_iext_destroy(struct xfs_ifork *);
153 struct xfs_bmbt_rec_host *
154 		xfs_iext_bno_to_ext(struct xfs_ifork *, xfs_fileoff_t, int *);
155 struct xfs_ext_irec *
156 		xfs_iext_bno_to_irec(struct xfs_ifork *, xfs_fileoff_t, int *);
157 struct xfs_ext_irec *
158 		xfs_iext_idx_to_irec(struct xfs_ifork *, xfs_extnum_t *, int *,
159 				     int);
160 void		xfs_iext_irec_init(struct xfs_ifork *);
161 struct xfs_ext_irec *
162 		xfs_iext_irec_new(struct xfs_ifork *, int);
163 void		xfs_iext_irec_remove(struct xfs_ifork *, int);
164 void		xfs_iext_irec_compact(struct xfs_ifork *);
165 void		xfs_iext_irec_compact_pages(struct xfs_ifork *);
166 void		xfs_iext_irec_compact_full(struct xfs_ifork *);
167 void		xfs_iext_irec_update_extoffs(struct xfs_ifork *, int, int);
168 
169 extern struct kmem_zone	*xfs_ifork_zone;
170 
171 #endif	/* __XFS_INODE_FORK_H__ */
172