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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 | |
18 | static 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 |
28 | static 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 */ |
92 | void 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 | |
166 | int 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 | } |
204 |
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