208 lines
7.0 KiB
C
208 lines
7.0 KiB
C
/*
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* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
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*/
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#include <linux/config.h>
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#include <linux/string.h>
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#include <linux/random.h>
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#include <linux/time.h>
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#include <linux/reiserfs_fs.h>
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#include <linux/reiserfs_fs_sb.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,
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"vs-15010: check_objectid_map: 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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/* 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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/* 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, "%s: no more object ids", __FUNCTION__);
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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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/* 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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map[1] = cpu_to_le32(unused_objectid + 1);
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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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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, s, 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, s, SB_BUFFER_WITH_SB(s));
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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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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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//map[i]++;
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map[i] = cpu_to_le32(le32_to_cpu(map[i]) + 1);
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/* Did we unallocate the last member of an odd sequence, and can shrink oids? */
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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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//disk_sb->s_oid_cursize -= 2;
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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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//objectid_map[i+1]--;
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map[i + 1] =
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cpu_to_le32(le32_to_cpu(map[i + 1]) - 1);
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return;
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}
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/* JDM comparing two little-endian values for equality -- safe */
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if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) {
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/* objectid map must be expanded, but there is no space */
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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_warning(s,
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"vs-15011: reiserfs_release_objectid: 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, *new_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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new_objectid_map = (__le32 *) (disk_sb + 1);
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if (cur_size > new_size) {
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/* mark everyone used that was listed as free at the end of the objectid
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** 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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