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216 lines
6.8 KiB
216 lines
6.8 KiB
/* |
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* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README |
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*/ |
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#include <linux/string.h> |
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#include <linux/time.h> |
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#include <linux/uuid.h> |
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#include "reiserfs.h" |
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/* find where objectid map starts */ |
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#define objectid_map(s,rs) (old_format_only (s) ? \ |
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(__le32 *)((struct reiserfs_super_block_v1 *)(rs) + 1) :\ |
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(__le32 *)((rs) + 1)) |
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#ifdef CONFIG_REISERFS_CHECK |
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static void check_objectid_map(struct super_block *s, __le32 * map) |
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{ |
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if (le32_to_cpu(map[0]) != 1) |
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reiserfs_panic(s, "vs-15010", "map corrupted: %lx", |
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(long unsigned int)le32_to_cpu(map[0])); |
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/* FIXME: add something else here */ |
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} |
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#else |
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static void check_objectid_map(struct super_block *s, __le32 * map) |
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{; |
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} |
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#endif |
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/* |
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* When we allocate objectids we allocate the first unused objectid. |
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* Each sequence of objectids in use (the odd sequences) is followed |
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* by a sequence of objectids not in use (the even sequences). We |
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* only need to record the last objectid in each of these sequences |
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* (both the odd and even sequences) in order to fully define the |
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* boundaries of the sequences. A consequence of allocating the first |
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* objectid not in use is that under most conditions this scheme is |
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* extremely compact. The exception is immediately after a sequence |
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* of operations which deletes a large number of objects of |
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* non-sequential objectids, and even then it will become compact |
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* again as soon as more objects are created. Note that many |
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* interesting optimizations of layout could result from complicating |
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* objectid assignment, but we have deferred making them for now. |
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*/ |
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/* get unique object identifier */ |
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__u32 reiserfs_get_unused_objectid(struct reiserfs_transaction_handle *th) |
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{ |
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struct super_block *s = th->t_super; |
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struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s); |
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__le32 *map = objectid_map(s, rs); |
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__u32 unused_objectid; |
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BUG_ON(!th->t_trans_id); |
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check_objectid_map(s, map); |
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reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1); |
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/* comment needed -Hans */ |
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unused_objectid = le32_to_cpu(map[1]); |
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if (unused_objectid == U32_MAX) { |
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reiserfs_warning(s, "reiserfs-15100", "no more object ids"); |
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reiserfs_restore_prepared_buffer(s, SB_BUFFER_WITH_SB(s)); |
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return 0; |
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} |
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/* |
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* This incrementation allocates the first unused objectid. That |
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* is to say, the first entry on the objectid map is the first |
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* unused objectid, and by incrementing it we use it. See below |
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* where we check to see if we eliminated a sequence of unused |
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* objectids.... |
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*/ |
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map[1] = cpu_to_le32(unused_objectid + 1); |
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/* |
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* Now we check to see if we eliminated the last remaining member of |
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* the first even sequence (and can eliminate the sequence by |
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* eliminating its last objectid from oids), and can collapse the |
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* first two odd sequences into one sequence. If so, then the net |
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* result is to eliminate a pair of objectids from oids. We do this |
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* by shifting the entire map to the left. |
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*/ |
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if (sb_oid_cursize(rs) > 2 && map[1] == map[2]) { |
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memmove(map + 1, map + 3, |
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(sb_oid_cursize(rs) - 3) * sizeof(__u32)); |
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set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2); |
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} |
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journal_mark_dirty(th, SB_BUFFER_WITH_SB(s)); |
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return unused_objectid; |
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} |
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/* makes object identifier unused */ |
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void reiserfs_release_objectid(struct reiserfs_transaction_handle *th, |
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__u32 objectid_to_release) |
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{ |
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struct super_block *s = th->t_super; |
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struct reiserfs_super_block *rs = SB_DISK_SUPER_BLOCK(s); |
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__le32 *map = objectid_map(s, rs); |
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int i = 0; |
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BUG_ON(!th->t_trans_id); |
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/*return; */ |
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check_objectid_map(s, map); |
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reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1); |
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journal_mark_dirty(th, SB_BUFFER_WITH_SB(s)); |
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/* |
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* start at the beginning of the objectid map (i = 0) and go to |
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* the end of it (i = disk_sb->s_oid_cursize). Linear search is |
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* what we use, though it is possible that binary search would be |
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* more efficient after performing lots of deletions (which is |
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* when oids is large.) We only check even i's. |
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*/ |
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while (i < sb_oid_cursize(rs)) { |
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if (objectid_to_release == le32_to_cpu(map[i])) { |
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/* This incrementation unallocates the objectid. */ |
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le32_add_cpu(&map[i], 1); |
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/* |
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* Did we unallocate the last member of an |
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* odd sequence, and can shrink oids? |
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*/ |
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if (map[i] == map[i + 1]) { |
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/* shrink objectid map */ |
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memmove(map + i, map + i + 2, |
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(sb_oid_cursize(rs) - i - |
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2) * sizeof(__u32)); |
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set_sb_oid_cursize(rs, sb_oid_cursize(rs) - 2); |
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RFALSE(sb_oid_cursize(rs) < 2 || |
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sb_oid_cursize(rs) > sb_oid_maxsize(rs), |
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"vs-15005: objectid map corrupted cur_size == %d (max == %d)", |
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sb_oid_cursize(rs), sb_oid_maxsize(rs)); |
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} |
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return; |
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} |
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if (objectid_to_release > le32_to_cpu(map[i]) && |
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objectid_to_release < le32_to_cpu(map[i + 1])) { |
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/* size of objectid map is not changed */ |
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if (objectid_to_release + 1 == le32_to_cpu(map[i + 1])) { |
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le32_add_cpu(&map[i + 1], -1); |
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return; |
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} |
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/* |
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* JDM comparing two little-endian values for |
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* equality -- safe |
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*/ |
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/* |
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* objectid map must be expanded, but |
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* there is no space |
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*/ |
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if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) { |
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PROC_INFO_INC(s, leaked_oid); |
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return; |
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} |
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/* expand the objectid map */ |
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memmove(map + i + 3, map + i + 1, |
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(sb_oid_cursize(rs) - i - 1) * sizeof(__u32)); |
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map[i + 1] = cpu_to_le32(objectid_to_release); |
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map[i + 2] = cpu_to_le32(objectid_to_release + 1); |
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set_sb_oid_cursize(rs, sb_oid_cursize(rs) + 2); |
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return; |
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} |
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i += 2; |
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} |
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reiserfs_error(s, "vs-15011", "tried to free free object id (%lu)", |
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(long unsigned)objectid_to_release); |
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} |
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int reiserfs_convert_objectid_map_v1(struct super_block *s) |
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{ |
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struct reiserfs_super_block *disk_sb = SB_DISK_SUPER_BLOCK(s); |
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int cur_size = sb_oid_cursize(disk_sb); |
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int new_size = (s->s_blocksize - SB_SIZE) / sizeof(__u32) / 2 * 2; |
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int old_max = sb_oid_maxsize(disk_sb); |
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struct reiserfs_super_block_v1 *disk_sb_v1; |
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__le32 *objectid_map; |
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int i; |
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disk_sb_v1 = |
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(struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data); |
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objectid_map = (__le32 *) (disk_sb_v1 + 1); |
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if (cur_size > new_size) { |
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/* |
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* mark everyone used that was listed as free at |
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* the end of the objectid map |
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*/ |
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objectid_map[new_size - 1] = objectid_map[cur_size - 1]; |
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set_sb_oid_cursize(disk_sb, new_size); |
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} |
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/* move the smaller objectid map past the end of the new super */ |
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for (i = new_size - 1; i >= 0; i--) { |
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objectid_map[i + (old_max - new_size)] = objectid_map[i]; |
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} |
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/* set the max size so we don't overflow later */ |
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set_sb_oid_maxsize(disk_sb, new_size); |
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/* Zero out label and generate random UUID */ |
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memset(disk_sb->s_label, 0, sizeof(disk_sb->s_label)); |
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generate_random_uuid(disk_sb->s_uuid); |
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/* finally, zero out the unused chunk of the new super */ |
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memset(disk_sb->s_unused, 0, sizeof(disk_sb->s_unused)); |
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return 0; |
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}
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