/* * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README */ #include <linux/string.h> #include <linux/random.h> #include <linux/time.h> #include <linux/reiserfs_fs.h> #include <linux/reiserfs_fs_sb.h> // find where objectid map starts #define objectid_map(s,rs) (old_format_only (s) ? \ (__le32 *)((struct reiserfs_super_block_v1 *)(rs) + 1) :\ (__le32 *)((rs) + 1)) #ifdef CONFIG_REISERFS_CHECK static void check_objectid_map(struct super_block *s, __le32 * map) { if (le32_to_cpu(map[0]) != 1) reiserfs_panic(s, "vs-15010: check_objectid_map: map corrupted: %lx", (long unsigned int)le32_to_cpu(map[0])); // FIXME: add something else here } #else static void check_objectid_map(struct super_block *s, __le32 * map) {; } #endif /* When we allocate objectids we allocate the first unused objectid. Each sequence of objectids in use (the odd sequences) is followed by a sequence of objectids not in use (the even sequences). We only need to record the last objectid in each of these sequences (both the odd and even sequences) in order to fully define the boundaries of the sequences. A consequence of allocating the first objectid not in use is that under most conditions this scheme is extremely compact. The exception is immediately after a sequence of operations which deletes a large number of objects of non-sequential objectids, and even then it will become compact again as soon as more objects are created. Note that many interesting optimizations of layout could result from complicating objectid assignment, but we have deferred making them for now. */ /* get unique object identifier */ __u32 reiserfs_get_unused_objectid(struct reiserfs_transaction_handle *th) { struct super_block *s = th->t_super; struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s); __le32 *map = objectid_map(s, rs); __u32 unused_objectid; BUG_ON(!th->t_trans_id); check_objectid_map(s, map); reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1); /* comment needed -Hans */ unused_objectid = le32_to_cpu(map[1]); if (unused_objectid == U32_MAX) { reiserfs_warning(s, "%s: no more object ids", __func__); reiserfs_restore_prepared_buffer(s, SB_BUFFER_WITH_SB(s)); return 0; } /* This incrementation allocates the first unused objectid. That is to say, the first entry on the objectid map is the first unused objectid, and by incrementing it we use it. See below where we check to see if we eliminated a sequence of unused objectids.... */ map[1] = cpu_to_le32(unused_objectid + 1); /* Now we check to see if we eliminated the last remaining member of the first even sequence (and can eliminate the sequence by eliminating its last objectid from oids), and can collapse the first two odd sequences into one sequence. If so, then the net result is to eliminate a pair of objectids from oids. We do this by shifting the entire map to the left. */ if (sb_oid_cursize(rs) > 2 && map[1] == map[2]) { memmove(map + 1, map + 3, (sb_oid_cursize(rs) - 3) * sizeof(__u32)); set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2); } journal_mark_dirty(th, s, SB_BUFFER_WITH_SB(s)); return unused_objectid; } /* makes object identifier unused */ void reiserfs_release_objectid(struct reiserfs_transaction_handle *th, __u32 objectid_to_release) { struct super_block *s = th->t_super; struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s); __le32 *map = objectid_map(s, rs); int i = 0; BUG_ON(!th->t_trans_id); //return; check_objectid_map(s, map); reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1); journal_mark_dirty(th, s, SB_BUFFER_WITH_SB(s)); /* start at the beginning of the objectid map (i = 0) and go to the end of it (i = disk_sb->s_oid_cursize). Linear search is what we use, though it is possible that binary search would be more efficient after performing lots of deletions (which is when oids is large.) We only check even i's. */ while (i < sb_oid_cursize(rs)) { if (objectid_to_release == le32_to_cpu(map[i])) { /* This incrementation unallocates the objectid. */ //map[i]++; le32_add_cpu(&map[i], 1); /* Did we unallocate the last member of an odd sequence, and can shrink oids? */ if (map[i] == map[i + 1]) { /* shrink objectid map */ memmove(map + i, map + i + 2, (sb_oid_cursize(rs) - i - 2) * sizeof(__u32)); //disk_sb->s_oid_cursize -= 2; set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2); RFALSE(sb_oid_cursize(rs) < 2 || sb_oid_cursize(rs) > sb_oid_maxsize(rs), "vs-15005: objectid map corrupted cur_size == %d (max == %d)", sb_oid_cursize(rs), sb_oid_maxsize(rs)); } return; } if (objectid_to_release > le32_to_cpu(map[i]) && objectid_to_release < le32_to_cpu(map[i + 1])) { /* size of objectid map is not changed */ if (objectid_to_release + 1 == le32_to_cpu(map[i + 1])) { //objectid_map[i+1]--; le32_add_cpu(&map[i + 1], -1); return; } /* JDM comparing two little-endian values for equality -- safe */ if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) { /* objectid map must be expanded, but there is no space */ PROC_INFO_INC(s, leaked_oid); return; } /* expand the objectid map */ memmove(map + i + 3, map + i + 1, (sb_oid_cursize(rs) - i - 1) * sizeof(__u32)); map[i + 1] = cpu_to_le32(objectid_to_release); map[i + 2] = cpu_to_le32(objectid_to_release + 1); set_sb_oid_cursize(rs, sb_oid_cursize(rs) + 2); return; } i += 2; } reiserfs_warning(s, "vs-15011: reiserfs_release_objectid: tried to free free object id (%lu)", (long unsigned)objectid_to_release); } int reiserfs_convert_objectid_map_v1(struct super_block *s) { struct reiserfs_super_block *disk_sb = SB_DISK_SUPER_BLOCK(s); int cur_size = sb_oid_cursize(disk_sb); int new_size = (s->s_blocksize - SB_SIZE) / sizeof(__u32) / 2 * 2; int old_max = sb_oid_maxsize(disk_sb); struct reiserfs_super_block_v1 *disk_sb_v1; __le32 *objectid_map, *new_objectid_map; int i; disk_sb_v1 = (struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data); objectid_map = (__le32 *) (disk_sb_v1 + 1); new_objectid_map = (__le32 *) (disk_sb + 1); if (cur_size > new_size) { /* mark everyone used that was listed as free at the end of the objectid ** map */ objectid_map[new_size - 1] = objectid_map[cur_size - 1]; set_sb_oid_cursize(disk_sb, new_size); } /* move the smaller objectid map past the end of the new super */ for (i = new_size - 1; i >= 0; i--) { objectid_map[i + (old_max - new_size)] = objectid_map[i]; } /* set the max size so we don't overflow later */ set_sb_oid_maxsize(disk_sb, new_size); /* Zero out label and generate random UUID */ memset(disk_sb->s_label, 0, sizeof(disk_sb->s_label)); generate_random_uuid(disk_sb->s_uuid); /* finally, zero out the unused chunk of the new super */ memset(disk_sb->s_unused, 0, sizeof(disk_sb->s_unused)); return 0; }