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xfs: introduce the CoW fork
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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
21struct xfs_inode_log_item;
34b8c759 22struct xfs_dinode;
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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 */
43typedef 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
56typedef 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 : \
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95 ((w) == XFS_ATTR_FORK ? \
96 (ip)->i_afp : \
97 (ip)->i_cowfp))
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98#define XFS_IFORK_DSIZE(ip) \
99 (XFS_IFORK_Q(ip) ? \
100 XFS_IFORK_BOFF(ip) : \
101 XFS_LITINO((ip)->i_mount, (ip)->i_d.di_version))
102#define XFS_IFORK_ASIZE(ip) \
103 (XFS_IFORK_Q(ip) ? \
104 XFS_LITINO((ip)->i_mount, (ip)->i_d.di_version) - \
105 XFS_IFORK_BOFF(ip) : \
106 0)
107#define XFS_IFORK_SIZE(ip,w) \
108 ((w) == XFS_DATA_FORK ? \
109 XFS_IFORK_DSIZE(ip) : \
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110 ((w) == XFS_ATTR_FORK ? \
111 XFS_IFORK_ASIZE(ip) : \
112 0))
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113#define XFS_IFORK_FORMAT(ip,w) \
114 ((w) == XFS_DATA_FORK ? \
115 (ip)->i_d.di_format : \
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116 ((w) == XFS_ATTR_FORK ? \
117 (ip)->i_d.di_aformat : \
118 (ip)->i_cformat))
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119#define XFS_IFORK_FMT_SET(ip,w,n) \
120 ((w) == XFS_DATA_FORK ? \
121 ((ip)->i_d.di_format = (n)) : \
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122 ((w) == XFS_ATTR_FORK ? \
123 ((ip)->i_d.di_aformat = (n)) : \
124 ((ip)->i_cformat = (n))))
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125#define XFS_IFORK_NEXTENTS(ip,w) \
126 ((w) == XFS_DATA_FORK ? \
127 (ip)->i_d.di_nextents : \
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128 ((w) == XFS_ATTR_FORK ? \
129 (ip)->i_d.di_anextents : \
130 (ip)->i_cnextents))
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131#define XFS_IFORK_NEXT_SET(ip,w,n) \
132 ((w) == XFS_DATA_FORK ? \
133 ((ip)->i_d.di_nextents = (n)) : \
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134 ((w) == XFS_ATTR_FORK ? \
135 ((ip)->i_d.di_anextents = (n)) : \
136 ((ip)->i_cnextents = (n))))
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137#define XFS_IFORK_MAXEXT(ip, w) \
138 (XFS_IFORK_SIZE(ip, w) / sizeof(xfs_bmbt_rec_t))
139
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140struct xfs_ifork *xfs_iext_state_to_fork(struct xfs_inode *ip, int state);
141
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142int xfs_iformat_fork(struct xfs_inode *, struct xfs_dinode *);
143void xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
ff105f75 144 struct xfs_inode_log_item *, int);
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145void xfs_idestroy_fork(struct xfs_inode *, int);
146void xfs_idata_realloc(struct xfs_inode *, int, int);
147void xfs_iroot_realloc(struct xfs_inode *, int, int);
148int xfs_iread_extents(struct xfs_trans *, struct xfs_inode *, int);
149int xfs_iextents_copy(struct xfs_inode *, struct xfs_bmbt_rec *,
150 int);
219eec76 151void xfs_init_local_fork(struct xfs_inode *, int, const void *, int);
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152
153struct xfs_bmbt_rec_host *
154 xfs_iext_get_ext(struct xfs_ifork *, xfs_extnum_t);
155void xfs_iext_insert(struct xfs_inode *, xfs_extnum_t, xfs_extnum_t,
156 struct xfs_bmbt_irec *, int);
157void xfs_iext_add(struct xfs_ifork *, xfs_extnum_t, int);
158void xfs_iext_add_indirect_multi(struct xfs_ifork *, int,
159 xfs_extnum_t, int);
160void xfs_iext_remove(struct xfs_inode *, xfs_extnum_t, int, int);
161void xfs_iext_remove_inline(struct xfs_ifork *, xfs_extnum_t, int);
162void xfs_iext_remove_direct(struct xfs_ifork *, xfs_extnum_t, int);
163void xfs_iext_remove_indirect(struct xfs_ifork *, xfs_extnum_t, int);
164void xfs_iext_realloc_direct(struct xfs_ifork *, int);
165void xfs_iext_direct_to_inline(struct xfs_ifork *, xfs_extnum_t);
166void xfs_iext_inline_to_direct(struct xfs_ifork *, int);
167void xfs_iext_destroy(struct xfs_ifork *);
168struct xfs_bmbt_rec_host *
169 xfs_iext_bno_to_ext(struct xfs_ifork *, xfs_fileoff_t, int *);
170struct xfs_ext_irec *
171 xfs_iext_bno_to_irec(struct xfs_ifork *, xfs_fileoff_t, int *);
172struct xfs_ext_irec *
173 xfs_iext_idx_to_irec(struct xfs_ifork *, xfs_extnum_t *, int *,
174 int);
175void xfs_iext_irec_init(struct xfs_ifork *);
176struct xfs_ext_irec *
177 xfs_iext_irec_new(struct xfs_ifork *, int);
178void xfs_iext_irec_remove(struct xfs_ifork *, int);
179void xfs_iext_irec_compact(struct xfs_ifork *);
180void xfs_iext_irec_compact_pages(struct xfs_ifork *);
181void xfs_iext_irec_compact_full(struct xfs_ifork *);
182void xfs_iext_irec_update_extoffs(struct xfs_ifork *, int, int);
183
184extern struct kmem_zone *xfs_ifork_zone;
185
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186extern void xfs_ifork_init_cow(struct xfs_inode *ip);
187
5d90ab5a 188#endif /* __XFS_INODE_FORK_H__ */