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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /fs/reiserfs/objectid.c
Initial import
Diffstat (limited to 'fs/reiserfs/objectid.c')
-rw-r--r--fs/reiserfs/objectid.c217
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;
+}