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bcachefs: Increase commality between BTREE_ITER_NODES and BTREE_ITER_KEYS

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Eventually BTREE_ITER_NODES should be going away. This patch is to fix a
transaction iterator overflow in the btree node merge path because
BTREE_ITER_NODES iterators couldn't be reused.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2021-04-02 21:29:05 -04:00 committed by Kent Overstreet
parent 2fa81d0b5b
commit 2d587674ba
2 changed files with 53 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
fs/bcachefs/btree_iter.c
View File

@ -432,25 +432,24 @@ bool __bch2_btree_iter_upgrade(struct btree_iter *iter,
}
void __bch2_btree_iter_downgrade(struct btree_iter *iter,
unsigned downgrade_to)
unsigned new_locks_want)
{
unsigned l, new_locks_want = downgrade_to ?:
(iter->flags & BTREE_ITER_INTENT ? 1 : 0);
unsigned l;
if (iter->locks_want < downgrade_to) {
iter->locks_want = new_locks_want;
EBUG_ON(iter->locks_want < new_locks_want);
while (iter->nodes_locked &&
(l = __fls(iter->nodes_locked)) >= iter->locks_want) {
if (l > iter->level) {
btree_node_unlock(iter, l);
} else {
if (btree_node_intent_locked(iter, l)) {
six_lock_downgrade(&iter->l[l].b->c.lock);
iter->nodes_intent_locked ^= 1 << l;
}
break;
iter->locks_want = new_locks_want;
while (iter->nodes_locked &&
(l = __fls(iter->nodes_locked)) >= iter->locks_want) {
if (l > iter->level) {
btree_node_unlock(iter, l);
} else {
if (btree_node_intent_locked(iter, l)) {
six_lock_downgrade(&iter->l[l].b->c.lock);
iter->nodes_intent_locked ^= 1 << l;
}
break;
}
}
@ -1993,6 +1992,8 @@ static inline void btree_iter_copy(struct btree_iter *dst,
struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
enum btree_id btree_id, struct bpos pos,
unsigned locks_want,
unsigned depth,
unsigned flags)
{
struct btree_iter *iter, *best = NULL;
@ -2005,10 +2006,6 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
pos.snapshot = btree_type_has_snapshots(btree_id)
? U32_MAX : 0;
/* We always want a fresh iterator for node iterators: */
if ((flags & BTREE_ITER_TYPE) == BTREE_ITER_NODES)
goto alloc_iter;
trans_for_each_iter(trans, iter) {
if (btree_iter_type(iter) != (flags & BTREE_ITER_TYPE))
continue;
@ -2023,7 +2020,7 @@ struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
best = iter;
}
alloc_iter:
if (!best) {
iter = btree_trans_iter_alloc(trans);
bch2_btree_iter_init(trans, iter, btree_id);
@ -2047,13 +2044,26 @@ alloc_iter:
iter->snapshot = pos.snapshot;
if (!(iter->flags & BTREE_ITER_INTENT))
bch2_btree_iter_downgrade(iter);
else if (!iter->locks_want) {
iter->locks_want = 1;
locks_want = min(locks_want, BTREE_MAX_DEPTH);
if (locks_want > iter->locks_want) {
iter->locks_want = locks_want;
btree_iter_get_locks(iter, true, false);
} else if (locks_want < iter->locks_want) {
__bch2_btree_iter_downgrade(iter, locks_want);
}
while (iter->level < depth) {
btree_node_unlock(iter, iter->level);
iter->l[iter->level].b = BTREE_ITER_NO_NODE_INIT;
iter->level++;
}
while (iter->level > depth)
iter->l[--iter->level].b = BTREE_ITER_NO_NODE_INIT;
iter->min_depth = depth;
bch2_btree_iter_set_pos(iter, pos);
btree_iter_set_search_pos(iter, btree_iter_search_key(iter));
@ -2069,21 +2079,16 @@ struct btree_iter *bch2_trans_get_node_iter(struct btree_trans *trans,
{
struct btree_iter *iter =
__bch2_trans_get_iter(trans, btree_id, pos,
BTREE_ITER_NODES|
BTREE_ITER_NOT_EXTENTS|
BTREE_ITER_ALL_SNAPSHOTS|
flags);
unsigned i;
locks_want, depth,
BTREE_ITER_NODES|
BTREE_ITER_NOT_EXTENTS|
BTREE_ITER_ALL_SNAPSHOTS|
flags);
BUG_ON(bkey_cmp(iter->pos, pos));
iter->locks_want = locks_want;
iter->level = depth;
iter->min_depth = depth;
for (i = 0; i < ARRAY_SIZE(iter->l); i++)
iter->l[i].b = NULL;
iter->l[iter->level].b = BTREE_ITER_NO_NODE_INIT;
BUG_ON(iter->locks_want != min(locks_want, BTREE_MAX_DEPTH));
BUG_ON(iter->level != depth);
BUG_ON(iter->min_depth != depth);
iter->ip_allocated = _RET_IP_;
return iter;
@ -2325,6 +2330,7 @@ bch2_btree_iter_node_to_text(struct printbuf *out,
bch2_bpos_to_text(out, btree_node_pos(_b, type));
}
#ifdef CONFIG_BCACHEFS_DEBUG
static bool trans_has_btree_nodes_locked(struct btree_trans *trans)
{
struct btree_iter *iter;
@ -2335,6 +2341,7 @@ static bool trans_has_btree_nodes_locked(struct btree_trans *trans)
return true;
return false;
}
#endif
void bch2_btree_trans_to_text(struct printbuf *out, struct bch_fs *c)
{

13
fs/bcachefs/btree_iter.h
View File

@ -131,8 +131,10 @@ void __bch2_btree_iter_downgrade(struct btree_iter *, unsigned);
static inline void bch2_btree_iter_downgrade(struct btree_iter *iter)
{
if (iter->locks_want > (iter->flags & BTREE_ITER_INTENT) ? 1 : 0)
__bch2_btree_iter_downgrade(iter, 0);
unsigned new_locks_want = (iter->flags & BTREE_ITER_INTENT ? 1 : 0);
if (iter->locks_want > new_locks_want)
__bch2_btree_iter_downgrade(iter, new_locks_want);
}
void bch2_trans_downgrade(struct btree_trans *);
@ -258,14 +260,17 @@ int bch2_trans_iter_free(struct btree_trans *, struct btree_iter *);
void bch2_trans_unlink_iters(struct btree_trans *);
struct btree_iter *__bch2_trans_get_iter(struct btree_trans *, enum btree_id,
struct bpos, unsigned);
struct bpos, unsigned,
unsigned, unsigned);
static inline struct btree_iter *
bch2_trans_get_iter(struct btree_trans *trans, enum btree_id btree_id,
struct bpos pos, unsigned flags)
{
struct btree_iter *iter =
__bch2_trans_get_iter(trans, btree_id, pos, flags);
__bch2_trans_get_iter(trans, btree_id, pos,
(flags & BTREE_ITER_INTENT) != 0, 0,
flags);
iter->ip_allocated = _THIS_IP_;
return iter;
}