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/*
* 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, 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);
__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, 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. */
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;
}
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