2 * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
5 #include <linux/string.h>
6 #include <linux/random.h>
7 #include <linux/time.h>
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) :\
15 #ifdef CONFIG_REISERFS_CHECK
17 static void check_objectid_map(struct super_block *s, __le32 * map)
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]));
23 /* FIXME: add something else here */
27 static void check_objectid_map(struct super_block *s, __le32 * map)
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.
48 /* get unique object identifier */
49 __u32 reiserfs_get_unused_objectid(struct reiserfs_transaction_handle *th)
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;
56 BUG_ON(!th->t_trans_id);
58 check_objectid_map(s, map);
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));
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
76 map[1] = cpu_to_le32(unused_objectid + 1);
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.
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);
92 journal_mark_dirty(th, SB_BUFFER_WITH_SB(s));
93 return unused_objectid;
96 /* makes object identifier unused */
97 void reiserfs_release_objectid(struct reiserfs_transaction_handle *th,
98 __u32 objectid_to_release)
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);
105 BUG_ON(!th->t_trans_id);
107 check_objectid_map(s, map);
109 reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
110 journal_mark_dirty(th, SB_BUFFER_WITH_SB(s));
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.
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);
125 * Did we unallocate the last member of an
126 * odd sequence, and can shrink oids?
128 if (map[i] == map[i + 1]) {
129 /* shrink objectid map */
130 memmove(map + i, map + i + 2,
131 (sb_oid_cursize(rs) - i -
133 set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2);
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));
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);
152 * JDM comparing two little-endian values for
156 * objectid map must be expanded, but
159 if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) {
160 PROC_INFO_INC(s, leaked_oid);
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);
175 reiserfs_error(s, "vs-15011", "tried to free free object id (%lu)",
176 (long unsigned)objectid_to_release);
179 int reiserfs_convert_objectid_map_v1(struct super_block *s)
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, *new_objectid_map;
190 (struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data);
191 objectid_map = (__le32 *) (disk_sb_v1 + 1);
192 new_objectid_map = (__le32 *) (disk_sb + 1);
194 if (cur_size > new_size) {
196 * mark everyone used that was listed as free at
197 * the end of the objectid map
199 objectid_map[new_size - 1] = objectid_map[cur_size - 1];
200 set_sb_oid_cursize(disk_sb, new_size);
202 /* move the smaller objectid map past the end of the new super */
203 for (i = new_size - 1; i >= 0; i--) {
204 objectid_map[i + (old_max - new_size)] = objectid_map[i];
207 /* set the max size so we don't overflow later */
208 set_sb_oid_maxsize(disk_sb, new_size);
210 /* Zero out label and generate random UUID */
211 memset(disk_sb->s_label, 0, sizeof(disk_sb->s_label));
212 generate_random_uuid(disk_sb->s_uuid);
214 /* finally, zero out the unused chunk of the new super */
215 memset(disk_sb->s_unused, 0, sizeof(disk_sb->s_unused));