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 } 206 207