/*
* Chop inums
* return value:
* < 0 - error
* 1 - modified
* 0 - not modified
*/
static int ileaf_chop(struct btree *btree, tuxkey_t start, u64 len, void *leaf)
{
struct ileaf *ileaf = leaf;
__be16 *dict = ileaf_dict(btree, leaf);
tuxkey_t base = ibase(ileaf);
unsigned count = icount(ileaf);
tuxkey_t at = start - base;
void *startp, *endp, *tailp;
unsigned size;
if (at + 1 > count)
return 0;
len = min_t(u64, len, count - at);
startp = ileaf->table + atdict(dict, at);
endp = ileaf->table + atdict(dict, at + len);
if (startp == endp)
return 0;
/* Remove data */
tailp = ileaf->table + atdict(dict, count);
memmove(startp, endp, tailp - endp);
/* Adjust dict */
size = endp - startp;
while (at < count) {
at++;
add_idict(dict - at, -size);
}
ileaf_trim(btree, leaf);
return 1;
}
static tuxkey_t ileaf_split(struct btree *btree, tuxkey_t hint,
void *from, void *into)
{
assert(ileaf_sniff(btree, from));
struct ileaf *leaf = from, *dest = into;
__be16 *dict = ileaf_dict(btree, from);
__be16 *destdict = ileaf_dict(btree, into);
#ifdef SPLIT_AT_INUM
/*
* This is to prevent to have same ibase on both of from and into
* FIXME: we would want to split at better position.
*/
if (hint == ibase(leaf))
hint++;
trace("split at inum 0x%Lx", hint);
unsigned at = min_t(tuxkey_t, hint - ibase(leaf), icount(leaf));
#else
/* binsearch inum starting nearest middle of block */
unsigned at = 1, hi = icount(leaf);
while (at < hi) {
int mid = (at + hi) / 2;
if (*(dict - mid) < (btree->sb->blocksize / 2))
at = mid + 1;
else
hi = mid;
}
#endif
/* should trim leading empty inodes on copy */
unsigned split = atdict(dict, at), free = atdict(dict, icount(leaf));
trace("split at %x of %x", at, icount(leaf));
trace("copy out %x bytes at %x", free - split, split);
assert(free >= split);
memcpy(dest->table, leaf->table + split, free - split);
dest->count = cpu_to_be16(icount(leaf) - at);
veccopy(destdict - icount(dest), dict - icount(leaf), icount(dest));
for (int i = 1; i <= icount(dest); i++)
add_idict(destdict - i, -split);
#ifdef SPLIT_AT_INUM
/* round down to multiple of 64 above ibase */
inum_t round = hint & ~(inum_t)(btree->entries_per_leaf - 1);
dest->ibase = cpu_to_be64(round > ibase(leaf) + icount(leaf) ? round : hint);
#else
dest->ibase = cpu_to_be64(ibase(leaf) + at);
#endif
leaf->count = cpu_to_be16(at);
memset(leaf->table + split, 0, (char *)(dict - icount(leaf)) - (leaf->table + split));
ileaf_trim(btree, leaf);
return ibase(dest);
}
int ileaf_purge(struct btree *btree, inum_t inum, struct ileaf *leaf)
{
if (inum < ibase(leaf) || inum - ibase(leaf) >= btree->entries_per_leaf)
return -EINVAL;
be_u16 *dict = (void *)leaf + btree->sb->blocksize;
unsigned at = inum - ibase(leaf);
unsigned offset = atdict(dict, at);
unsigned size = from_be_u16(*(dict - at - 1)) - offset;
printf("delete inode %Lx from %p[%x/%x]\n", (L)inum, leaf, at, size);
if (!size)
return -ENOENT;
unsigned free = from_be_u16(*(dict - icount(leaf))), tail = free - offset - size;
assert(offset + size + tail <= free);
memmove(leaf->table + offset, leaf->table + offset + size, tail);
for (int i = at + 1; i <= icount(leaf); i++)
add_idict(dict - i, -size);
ileaf_trim(btree, leaf);
return 0;
}
static tuxkey_t ileaf_split(struct btree *btree, tuxkey_t inum, vleaf *from, vleaf *into)
{
assert(ileaf_sniff(btree, from));
struct ileaf *leaf = from, *dest = into;
be_u16 *dict = from + btree->sb->blocksize, *destdict = into + btree->sb->blocksize;
#ifdef SPLIT_AT_INUM
printf("split at inum 0x%Lx\n", (L)inum);
assert(inum >= ibase(leaf));
unsigned at = inum - ibase(leaf) < icount(leaf) ? inum - ibase(leaf) : icount(leaf);
#else
/* binsearch inum starting nearest middle of block */
unsigned at = 1, hi = icount(leaf);
while (at < hi) {
int mid = (at + hi) / 2;
if (*(dict - mid) < (btree->sb->blocksize / 2))
at = mid + 1;
else
hi = mid;
}
#endif
/* should trim leading empty inodes on copy */
unsigned split = atdict(dict, at), free = from_be_u16(*(dict - icount(leaf)));
printf("split at %x of %x\n", at, icount(leaf));
printf("copy out %x bytes at %x\n", free - split, split);
assert(free >= split);
memcpy(dest->table, leaf->table + split, free - split);
dest->count = to_be_u16(icount(leaf) - at);
veccopy(destdict - icount(dest), dict - icount(leaf), icount(dest));
for (int i = 1; i <= icount(dest); i++)
add_idict(destdict - i, -split);
#ifdef SPLIT_AT_INUM
/* round down to multiple of 64 above ibase */
inum_t round = inum & ~(inum_t)(btree->entries_per_leaf - 1);
dest->ibase = to_be_u64(round > ibase(leaf) + icount(leaf) ? round : inum);
#else
dest->ibase = to_be_u64(ibase(leaf) + at);
#endif
leaf->count = to_be_u16(at);
memset(leaf->table + split, 0, (char *)(dict - icount(leaf)) - (leaf->table + split));
ileaf_trim(btree, leaf);
return ibase(dest);
}
