1 files changed, 217 insertions, 0 deletions
diff --git a/fs/reiserfs/objectid.c b/fs/reiserfs/objectid.c
new file mode 100644
index 000000000..99a5d5dae
--- /dev/null
+++ b/fs/reiserfs/objectid.c
@@ -0,0 +1,217 @@
+/*
+ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
+ */
+
+#include <linux/string.h>
+#include <linux/random.h>
+#include <linux/time.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;
+}