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1da177e4 LT |
1 | /* |
2 | * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README | |
3 | */ | |
4 | ||
5 | #include <linux/config.h> | |
6 | #include <linux/string.h> | |
7 | #include <linux/random.h> | |
8 | #include <linux/time.h> | |
9 | #include <linux/reiserfs_fs.h> | |
10 | #include <linux/reiserfs_fs_sb.h> | |
11 | ||
12 | // find where objectid map starts | |
13 | #define objectid_map(s,rs) (old_format_only (s) ? \ | |
14 | (__u32 *)((struct reiserfs_super_block_v1 *)(rs) + 1) :\ | |
15 | (__u32 *)((rs) + 1)) | |
16 | ||
17 | ||
18 | #ifdef CONFIG_REISERFS_CHECK | |
19 | ||
20 | static void check_objectid_map (struct super_block * s, __u32 * map) | |
21 | { | |
22 | if (le32_to_cpu (map[0]) != 1) | |
23 | reiserfs_panic (s, "vs-15010: check_objectid_map: map corrupted: %lx", | |
24 | ( long unsigned int ) le32_to_cpu (map[0])); | |
25 | ||
26 | // FIXME: add something else here | |
27 | } | |
28 | ||
29 | #else | |
30 | static void check_objectid_map (struct super_block * s, __u32 * map) | |
31 | {;} | |
32 | #endif | |
33 | ||
34 | ||
35 | /* When we allocate objectids we allocate the first unused objectid. | |
36 | Each sequence of objectids in use (the odd sequences) is followed | |
37 | by a sequence of objectids not in use (the even sequences). We | |
38 | only need to record the last objectid in each of these sequences | |
39 | (both the odd and even sequences) in order to fully define the | |
40 | boundaries of the sequences. A consequence of allocating the first | |
41 | objectid not in use is that under most conditions this scheme is | |
42 | extremely compact. The exception is immediately after a sequence | |
43 | of operations which deletes a large number of objects of | |
44 | non-sequential objectids, and even then it will become compact | |
45 | again as soon as more objects are created. Note that many | |
46 | interesting optimizations of layout could result from complicating | |
47 | objectid assignment, but we have deferred making them for now. */ | |
48 | ||
49 | ||
50 | /* get unique object identifier */ | |
51 | __u32 reiserfs_get_unused_objectid (struct reiserfs_transaction_handle *th) | |
52 | { | |
53 | struct super_block * s = th->t_super; | |
54 | struct reiserfs_super_block * rs = SB_DISK_SUPER_BLOCK (s); | |
55 | __u32 * map = objectid_map (s, rs); | |
56 | __u32 unused_objectid; | |
57 | ||
58 | BUG_ON (!th->t_trans_id); | |
59 | ||
60 | check_objectid_map (s, map); | |
61 | ||
62 | reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1) ; | |
63 | /* comment needed -Hans */ | |
64 | unused_objectid = le32_to_cpu (map[1]); | |
65 | if (unused_objectid == U32_MAX) { | |
66 | reiserfs_warning (s, "%s: no more object ids", __FUNCTION__); | |
67 | reiserfs_restore_prepared_buffer(s, SB_BUFFER_WITH_SB(s)) ; | |
68 | return 0; | |
69 | } | |
70 | ||
71 | /* This incrementation allocates the first unused objectid. That | |
72 | is to say, the first entry on the objectid map is the first | |
73 | unused objectid, and by incrementing it we use it. See below | |
74 | where we check to see if we eliminated a sequence of unused | |
75 | objectids.... */ | |
76 | map[1] = cpu_to_le32 (unused_objectid + 1); | |
77 | ||
78 | /* Now we check to see if we eliminated the last remaining member of | |
79 | the first even sequence (and can eliminate the sequence by | |
80 | eliminating its last objectid from oids), and can collapse the | |
81 | first two odd sequences into one sequence. If so, then the net | |
82 | result is to eliminate a pair of objectids from oids. We do this | |
83 | by shifting the entire map to the left. */ | |
84 | if (sb_oid_cursize(rs) > 2 && map[1] == map[2]) { | |
85 | memmove (map + 1, map + 3, (sb_oid_cursize(rs) - 3) * sizeof(__u32)); | |
86 | set_sb_oid_cursize( rs, sb_oid_cursize(rs) - 2 ); | |
87 | } | |
88 | ||
89 | journal_mark_dirty(th, s, SB_BUFFER_WITH_SB (s)); | |
90 | return unused_objectid; | |
91 | } | |
92 | ||
93 | ||
94 | /* makes object identifier unused */ | |
95 | void reiserfs_release_objectid (struct reiserfs_transaction_handle *th, | |
96 | __u32 objectid_to_release) | |
97 | { | |
98 | struct super_block * s = th->t_super; | |
99 | struct reiserfs_super_block * rs = SB_DISK_SUPER_BLOCK (s); | |
100 | __u32 * map = objectid_map (s, rs); | |
101 | int i = 0; | |
102 | ||
103 | BUG_ON (!th->t_trans_id); | |
104 | //return; | |
105 | check_objectid_map (s, map); | |
106 | ||
107 | reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1) ; | |
108 | journal_mark_dirty(th, s, SB_BUFFER_WITH_SB (s)); | |
109 | ||
110 | /* start at the beginning of the objectid map (i = 0) and go to | |
111 | the end of it (i = disk_sb->s_oid_cursize). Linear search is | |
112 | what we use, though it is possible that binary search would be | |
113 | more efficient after performing lots of deletions (which is | |
114 | when oids is large.) We only check even i's. */ | |
115 | while (i < sb_oid_cursize(rs)) { | |
116 | if (objectid_to_release == le32_to_cpu (map[i])) { | |
117 | /* This incrementation unallocates the objectid. */ | |
118 | //map[i]++; | |
119 | map[i] = cpu_to_le32 (le32_to_cpu (map[i]) + 1); | |
120 | ||
121 | /* Did we unallocate the last member of an odd sequence, and can shrink oids? */ | |
122 | if (map[i] == map[i+1]) { | |
123 | /* shrink objectid map */ | |
124 | memmove (map + i, map + i + 2, | |
125 | (sb_oid_cursize(rs) - i - 2) * sizeof (__u32)); | |
126 | //disk_sb->s_oid_cursize -= 2; | |
127 | set_sb_oid_cursize( rs, sb_oid_cursize(rs) - 2 ); | |
128 | ||
129 | RFALSE( sb_oid_cursize(rs) < 2 || | |
130 | sb_oid_cursize(rs) > sb_oid_maxsize(rs), | |
131 | "vs-15005: objectid map corrupted cur_size == %d (max == %d)", | |
132 | sb_oid_cursize(rs), sb_oid_maxsize(rs)); | |
133 | } | |
134 | return; | |
135 | } | |
136 | ||
137 | if (objectid_to_release > le32_to_cpu (map[i]) && | |
138 | objectid_to_release < le32_to_cpu (map[i + 1])) { | |
139 | /* size of objectid map is not changed */ | |
140 | if (objectid_to_release + 1 == le32_to_cpu (map[i + 1])) { | |
141 | //objectid_map[i+1]--; | |
142 | map[i + 1] = cpu_to_le32 (le32_to_cpu (map[i + 1]) - 1); | |
143 | return; | |
144 | } | |
145 | ||
146 | /* JDM comparing two little-endian values for equality -- safe */ | |
147 | if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) { | |
148 | /* objectid map must be expanded, but there is no space */ | |
149 | PROC_INFO_INC( s, leaked_oid ); | |
150 | return; | |
151 | } | |
152 | ||
153 | /* expand the objectid map*/ | |
154 | memmove (map + i + 3, map + i + 1, | |
155 | (sb_oid_cursize(rs) - i - 1) * sizeof(__u32)); | |
156 | map[i + 1] = cpu_to_le32 (objectid_to_release); | |
157 | map[i + 2] = cpu_to_le32 (objectid_to_release + 1); | |
158 | set_sb_oid_cursize( rs, sb_oid_cursize(rs) + 2 ); | |
159 | return; | |
160 | } | |
161 | i += 2; | |
162 | } | |
163 | ||
164 | reiserfs_warning (s, "vs-15011: reiserfs_release_objectid: tried to free free object id (%lu)", | |
165 | ( long unsigned ) objectid_to_release); | |
166 | } | |
167 | ||
168 | ||
169 | int reiserfs_convert_objectid_map_v1(struct super_block *s) { | |
170 | struct reiserfs_super_block *disk_sb = SB_DISK_SUPER_BLOCK (s); | |
171 | int cur_size = sb_oid_cursize(disk_sb); | |
172 | int new_size = (s->s_blocksize - SB_SIZE) / sizeof(__u32) / 2 * 2 ; | |
173 | int old_max = sb_oid_maxsize(disk_sb); | |
174 | struct reiserfs_super_block_v1 *disk_sb_v1 ; | |
175 | __u32 *objectid_map, *new_objectid_map ; | |
176 | int i ; | |
177 | ||
178 | disk_sb_v1=(struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data); | |
179 | objectid_map = (__u32 *)(disk_sb_v1 + 1) ; | |
180 | new_objectid_map = (__u32 *)(disk_sb + 1) ; | |
181 | ||
182 | if (cur_size > new_size) { | |
183 | /* mark everyone used that was listed as free at the end of the objectid | |
184 | ** map | |
185 | */ | |
186 | objectid_map[new_size - 1] = objectid_map[cur_size - 1] ; | |
187 | set_sb_oid_cursize(disk_sb,new_size) ; | |
188 | } | |
189 | /* move the smaller objectid map past the end of the new super */ | |
190 | for (i = new_size - 1 ; i >= 0 ; i--) { | |
191 | objectid_map[i + (old_max - new_size)] = objectid_map[i] ; | |
192 | } | |
193 | ||
194 | ||
195 | /* set the max size so we don't overflow later */ | |
196 | set_sb_oid_maxsize(disk_sb,new_size) ; | |
197 | ||
198 | /* Zero out label and generate random UUID */ | |
199 | memset(disk_sb->s_label, 0, sizeof(disk_sb->s_label)) ; | |
200 | generate_random_uuid(disk_sb->s_uuid); | |
201 | ||
202 | /* finally, zero out the unused chunk of the new super */ | |
203 | memset(disk_sb->s_unused, 0, sizeof(disk_sb->s_unused)) ; | |
204 | return 0 ; | |
205 | } | |
206 |