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linux
1/*
2 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
3 */
4
5#include <linux/string.h>
6#include <linux/random.h>
7#include <linux/time.h>
8#include <linux/reiserfs_fs.h>
9#include <linux/reiserfs_fs_sb.h>
10
11// find where objectid map starts
12#define objectid_map(s,rs) (old_format_only (s) ? \
13 (__le32 *)((struct reiserfs_super_block_v1 *)(rs) + 1) :\
14 (__le32 *)((rs) + 1))
15
16#ifdef CONFIG_REISERFS_CHECK
17
18static void check_objectid_map(struct super_block *s, __le32 * map)
19{
20 if (le32_to_cpu(map[0]) != 1)
21 reiserfs_panic(s, "vs-15010", "map corrupted: %lx",
22 (long unsigned int)le32_to_cpu(map[0]));
23
24 // FIXME: add something else here
25}
26
27#else
28static void check_objectid_map(struct super_block *s, __le32 * map)
29{;
30}
31#endif
32
33/* When we allocate objectids we allocate the first unused objectid.
34 Each sequence of objectids in use (the odd sequences) is followed
35 by a sequence of objectids not in use (the even sequences). We
36 only need to record the last objectid in each of these sequences
37 (both the odd and even sequences) in order to fully define the
38 boundaries of the sequences. A consequence of allocating the first
39 objectid not in use is that under most conditions this scheme is
40 extremely compact. The exception is immediately after a sequence
41 of operations which deletes a large number of objects of
42 non-sequential objectids, and even then it will become compact
43 again as soon as more objects are created. Note that many
44 interesting optimizations of layout could result from complicating
45 objectid assignment, but we have deferred making them for now. */
46
47/* get unique object identifier */
48__u32 reiserfs_get_unused_objectid(struct reiserfs_transaction_handle *th)
49{
50 struct super_block *s = th->t_super;
51 struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s);
52 __le32 *map = objectid_map(s, rs);
53 __u32 unused_objectid;
54
55 BUG_ON(!th->t_trans_id);
56
57 check_objectid_map(s, map);
58
59 reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
60 /* comment needed -Hans */
61 unused_objectid = le32_to_cpu(map[1]);
62 if (unused_objectid == U32_MAX) {
63 reiserfs_warning(s, "reiserfs-15100", "no more object ids");
64 reiserfs_restore_prepared_buffer(s, SB_BUFFER_WITH_SB(s));
65 return 0;
66 }
67
68 /* This incrementation allocates the first unused objectid. That
69 is to say, the first entry on the objectid map is the first
70 unused objectid, and by incrementing it we use it. See below
71 where we check to see if we eliminated a sequence of unused
72 objectids.... */
73 map[1] = cpu_to_le32(unused_objectid + 1);
74
75 /* Now we check to see if we eliminated the last remaining member of
76 the first even sequence (and can eliminate the sequence by
77 eliminating its last objectid from oids), and can collapse the
78 first two odd sequences into one sequence. If so, then the net
79 result is to eliminate a pair of objectids from oids. We do this
80 by shifting the entire map to the left. */
81 if (sb_oid_cursize(rs) > 2 && map[1] == map[2]) {
82 memmove(map + 1, map + 3,
83 (sb_oid_cursize(rs) - 3) * sizeof(__u32));
84 set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2);
85 }
86
87 journal_mark_dirty(th, s, SB_BUFFER_WITH_SB(s));
88 return unused_objectid;
89}
90
91/* makes object identifier unused */
92void reiserfs_release_objectid(struct reiserfs_transaction_handle *th,
93 __u32 objectid_to_release)
94{
95 struct super_block *s = th->t_super;
96 struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s);
97 __le32 *map = objectid_map(s, rs);
98 int i = 0;
99
100 BUG_ON(!th->t_trans_id);
101 //return;
102 check_objectid_map(s, map);
103
104 reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
105 journal_mark_dirty(th, s, SB_BUFFER_WITH_SB(s));
106
107 /* start at the beginning of the objectid map (i = 0) and go to
108 the end of it (i = disk_sb->s_oid_cursize). Linear search is
109 what we use, though it is possible that binary search would be
110 more efficient after performing lots of deletions (which is
111 when oids is large.) We only check even i's. */
112 while (i < sb_oid_cursize(rs)) {
113 if (objectid_to_release == le32_to_cpu(map[i])) {
114 /* This incrementation unallocates the objectid. */
115 //map[i]++;
116 le32_add_cpu(&map[i], 1);
117
118 /* Did we unallocate the last member of an odd sequence, and can shrink oids? */
119 if (map[i] == map[i + 1]) {
120 /* shrink objectid map */
121 memmove(map + i, map + i + 2,
122 (sb_oid_cursize(rs) - i -
123 2) * sizeof(__u32));
124 //disk_sb->s_oid_cursize -= 2;
125 set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2);
126
127 RFALSE(sb_oid_cursize(rs) < 2 ||
128 sb_oid_cursize(rs) > sb_oid_maxsize(rs),
129 "vs-15005: objectid map corrupted cur_size == %d (max == %d)",
130 sb_oid_cursize(rs), sb_oid_maxsize(rs));
131 }
132 return;
133 }
134
135 if (objectid_to_release > le32_to_cpu(map[i]) &&
136 objectid_to_release < le32_to_cpu(map[i + 1])) {
137 /* size of objectid map is not changed */
138 if (objectid_to_release + 1 == le32_to_cpu(map[i + 1])) {
139 //objectid_map[i+1]--;
140 le32_add_cpu(&map[i + 1], -1);
141 return;
142 }
143
144 /* JDM comparing two little-endian values for equality -- safe */
145 if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) {
146 /* objectid map must be expanded, but there is no space */
147 PROC_INFO_INC(s, leaked_oid);
148 return;
149 }
150
151 /* expand the objectid map */
152 memmove(map + i + 3, map + i + 1,
153 (sb_oid_cursize(rs) - i - 1) * sizeof(__u32));
154 map[i + 1] = cpu_to_le32(objectid_to_release);
155 map[i + 2] = cpu_to_le32(objectid_to_release + 1);
156 set_sb_oid_cursize(rs, sb_oid_cursize(rs) + 2);
157 return;
158 }
159 i += 2;
160 }
161
162 reiserfs_error(s, "vs-15011", "tried to free free object id (%lu)",
163 (long unsigned)objectid_to_release);
164}
165
166int reiserfs_convert_objectid_map_v1(struct super_block *s)
167{
168 struct reiserfs_super_block *disk_sb = SB_DISK_SUPER_BLOCK(s);
169 int cur_size = sb_oid_cursize(disk_sb);
170 int new_size = (s->s_blocksize - SB_SIZE) / sizeof(__u32) / 2 * 2;
171 int old_max = sb_oid_maxsize(disk_sb);
172 struct reiserfs_super_block_v1 *disk_sb_v1;
173 __le32 *objectid_map, *new_objectid_map;
174 int i;
175
176 disk_sb_v1 =
177 (struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data);
178 objectid_map = (__le32 *) (disk_sb_v1 + 1);
179 new_objectid_map = (__le32 *) (disk_sb + 1);
180
181 if (cur_size > new_size) {
182 /* mark everyone used that was listed as free at the end of the objectid
183 ** map
184 */
185 objectid_map[new_size - 1] = objectid_map[cur_size - 1];
186 set_sb_oid_cursize(disk_sb, new_size);
187 }
188 /* move the smaller objectid map past the end of the new super */
189 for (i = new_size - 1; i >= 0; i--) {
190 objectid_map[i + (old_max - new_size)] = objectid_map[i];
191 }
192
193 /* set the max size so we don't overflow later */
194 set_sb_oid_maxsize(disk_sb, new_size);
195
196 /* Zero out label and generate random UUID */
197 memset(disk_sb->s_label, 0, sizeof(disk_sb->s_label));
198 generate_random_uuid(disk_sb->s_uuid);
199
200 /* finally, zero out the unused chunk of the new super */
201 memset(disk_sb->s_unused, 0, sizeof(disk_sb->s_unused));
202 return 0;
203}