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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-17 02:20:36 +0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/reiserfs/objectid.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/reiserfs/objectid.c')
-rw-r--r--fs/reiserfs/objectid.c206
1 files changed, 206 insertions, 0 deletions
diff --git a/fs/reiserfs/objectid.c b/fs/reiserfs/objectid.c
new file mode 100644
index 000000000000..0785c43a7486
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+++ b/fs/reiserfs/objectid.c
@@ -0,0 +1,206 @@
+/*
+ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
+ */
+
+#include <linux/config.h>
+#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) ? \
+ (__u32 *)((struct reiserfs_super_block_v1 *)(rs) + 1) :\
+ (__u32 *)((rs) + 1))
+
+
+#ifdef CONFIG_REISERFS_CHECK
+
+static void check_objectid_map (struct super_block * s, __u32 * 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, __u32 * 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);
+ __u32 * 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", __FUNCTION__);
+ 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);
+ __u32 * 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]++;
+ map[i] = cpu_to_le32 (le32_to_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]--;
+ map[i + 1] = cpu_to_le32 (le32_to_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 ;
+ __u32 *objectid_map, *new_objectid_map ;
+ int i ;
+
+ disk_sb_v1=(struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data);
+ objectid_map = (__u32 *)(disk_sb_v1 + 1) ;
+ new_objectid_map = (__u32 *)(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 ;
+}
+