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fs/reiserfs/objectid.c
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/* * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README */ #include <linux/string.h> #include <linux/time.h> #include <linux/uuid.h> #include "reiserfs.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", "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, "reiserfs-15100", "no more object ids"); 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, 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, 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. */ 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)); 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])) { le32_add_cpu(&map[i + 1], -1); return; } /* * JDM comparing two little-endian values for * equality -- safe */ /* * objectid map must be expanded, but * there is no space */ if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) { 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_error(s, "vs-15011", "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; } |