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