1 /*
2 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
3 */
4
5 #include <linux/string.h>
6 #include <linux/time.h>
7 #include <linux/uuid.h>
8 #include "reiserfs.h"
9
10 /* find where objectid map starts */
11 #define objectid_map(s,rs) (old_format_only (s) ? \
12 (__le32 *)((struct reiserfs_super_block_v1 *)(rs) + 1) :\
13 (__le32 *)((rs) + 1))
14
15 #ifdef CONFIG_REISERFS_CHECK
16
17 static void check_objectid_map(struct super_block *s, __le32 * map)
18 {
19 if (le32_to_cpu(map[0]) != 1)
20 reiserfs_panic(s, "vs-15010", "map corrupted: %lx",
21 (long unsigned int)le32_to_cpu(map[0]));
22
23 /* FIXME: add something else here */
24 }
25
26 #else
27 static void check_objectid_map(struct super_block *s, __le32 * map)
28 {;
29 }
30 #endif
31
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
48 /* get unique object identifier */
49 __u32 reiserfs_get_unused_objectid(struct reiserfs_transaction_handle *th)
50 {
51 struct super_block *s = th->t_super;
52 struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s);
53 __le32 *map = objectid_map(s, rs);
54 __u32 unused_objectid;
55
56 BUG_ON(!th->t_trans_id);
57
58 check_objectid_map(s, map);
59
60 reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
61 /* comment needed -Hans */
62 unused_objectid = le32_to_cpu(map[1]);
63 if (unused_objectid == U32_MAX) {
64 reiserfs_warning(s, "reiserfs-15100", "no more object ids");
65 reiserfs_restore_prepared_buffer(s, SB_BUFFER_WITH_SB(s));
66 return 0;
67 }
68
69 /*
70 * This incrementation allocates the first unused objectid. That
71 * is to say, the first entry on the objectid map is the first
72 * unused objectid, and by incrementing it we use it. See below
73 * where we check to see if we eliminated a sequence of unused
74 * objectids....
75 */
76 map[1] = cpu_to_le32(unused_objectid + 1);
77
78 /*
79 * Now we check to see if we eliminated the last remaining member of
80 * the first even sequence (and can eliminate the sequence by
81 * eliminating its last objectid from oids), and can collapse the
82 * first two odd sequences into one sequence. If so, then the net
83 * result is to eliminate a pair of objectids from oids. We do this
84 * by shifting the entire map to the left.
85 */
86 if (sb_oid_cursize(rs) > 2 && map[1] == map[2]) {
87 memmove(map + 1, map + 3,
88 (sb_oid_cursize(rs) - 3) * sizeof(__u32));
89 set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2);
90 }
91
92 journal_mark_dirty(th, SB_BUFFER_WITH_SB(s));
93 return unused_objectid;
94 }
95
96 /* makes object identifier unused */
97 void reiserfs_release_objectid(struct reiserfs_transaction_handle *th,
98 __u32 objectid_to_release)
99 {
100 struct super_block *s = th->t_super;
101 struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s);
102 __le32 *map = objectid_map(s, rs);
103 int i = 0;
104
105 BUG_ON(!th->t_trans_id);
106 /*return; */
107 check_objectid_map(s, map);
108
109 reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
110 journal_mark_dirty(th, SB_BUFFER_WITH_SB(s));
111
112 /*
113 * start at the beginning of the objectid map (i = 0) and go to
114 * the end of it (i = disk_sb->s_oid_cursize). Linear search is
115 * what we use, though it is possible that binary search would be
116 * more efficient after performing lots of deletions (which is
117 * when oids is large.) We only check even i's.
118 */
119 while (i < sb_oid_cursize(rs)) {
120 if (objectid_to_release == le32_to_cpu(map[i])) {
121 /* This incrementation unallocates the objectid. */
122 le32_add_cpu(&map[i], 1);
123
124 /*
125 * Did we unallocate the last member of an
126 * odd sequence, and can shrink oids?
127 */
128 if (map[i] == map[i + 1]) {
129 /* shrink objectid map */
130 memmove(map + i, map + i + 2,
131 (sb_oid_cursize(rs) - i -
132 2) * sizeof(__u32));
133 set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2);
134
135 RFALSE(sb_oid_cursize(rs) < 2 ||
136 sb_oid_cursize(rs) > sb_oid_maxsize(rs),
137 "vs-15005: objectid map corrupted cur_size == %d (max == %d)",
138 sb_oid_cursize(rs), sb_oid_maxsize(rs));
139 }
140 return;
141 }
142
143 if (objectid_to_release > le32_to_cpu(map[i]) &&
144 objectid_to_release < le32_to_cpu(map[i + 1])) {
145 /* size of objectid map is not changed */
146 if (objectid_to_release + 1 == le32_to_cpu(map[i + 1])) {
147 le32_add_cpu(&map[i + 1], -1);
148 return;
149 }
150
151 /*
152 * JDM comparing two little-endian values for
153 * equality -- safe
154 */
155 /*
156 * objectid map must be expanded, but
157 * there is no space
158 */
159 if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) {
160 PROC_INFO_INC(s, leaked_oid);
161 return;
162 }
163
164 /* expand the objectid map */
165 memmove(map + i + 3, map + i + 1,
166 (sb_oid_cursize(rs) - i - 1) * sizeof(__u32));
167 map[i + 1] = cpu_to_le32(objectid_to_release);
168 map[i + 2] = cpu_to_le32(objectid_to_release + 1);
169 set_sb_oid_cursize(rs, sb_oid_cursize(rs) + 2);
170 return;
171 }
172 i += 2;
173 }
174
175 reiserfs_error(s, "vs-15011", "tried to free free object id (%lu)",
176 (long unsigned)objectid_to_release);
177 }
178
179 int reiserfs_convert_objectid_map_v1(struct super_block *s)
180 {
181 struct reiserfs_super_block *disk_sb = SB_DISK_SUPER_BLOCK(s);
182 int cur_size = sb_oid_cursize(disk_sb);
183 int new_size = (s->s_blocksize - SB_SIZE) / sizeof(__u32) / 2 * 2;
184 int old_max = sb_oid_maxsize(disk_sb);
185 struct reiserfs_super_block_v1 *disk_sb_v1;
186 __le32 *objectid_map;
187 int i;
188
189 disk_sb_v1 =
190 (struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data);
191 objectid_map = (__le32 *) (disk_sb_v1 + 1);
192
193 if (cur_size > new_size) {
194 /*
195 * mark everyone used that was listed as free at
196 * the end of the objectid map
197 */
198 objectid_map[new_size - 1] = objectid_map[cur_size - 1];
199 set_sb_oid_cursize(disk_sb, new_size);
200 }
201 /* move the smaller objectid map past the end of the new super */
202 for (i = new_size - 1; i >= 0; i--) {
203 objectid_map[i + (old_max - new_size)] = objectid_map[i];
204 }
205
206 /* set the max size so we don't overflow later */
207 set_sb_oid_maxsize(disk_sb, new_size);
208
209 /* Zero out label and generate random UUID */
210 memset(disk_sb->s_label, 0, sizeof(disk_sb->s_label));
211 generate_random_uuid(disk_sb->s_uuid);
212
213 /* finally, zero out the unused chunk of the new super */
214 memset(disk_sb->s_unused, 0, sizeof(disk_sb->s_unused));
215 return 0;
216 }