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|
// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "bkey_methods.h"
#include "btree_cache.h"
#include "btree_iter.h"
#include "btree_locking.h"
#include "debug.h"
#include "extents.h"
#include "trace.h"
#include <linux/prefetch.h>
static inline struct bkey_s_c __btree_iter_peek_all(struct btree_iter *,
struct btree_iter_level *,
struct bkey *);
#define BTREE_ITER_NOT_END ((struct btree *) 1)
static inline bool is_btree_node(struct btree_iter *iter, unsigned l)
{
return l < BTREE_MAX_DEPTH &&
iter->l[l].b &&
iter->l[l].b != BTREE_ITER_NOT_END;
}
/* Returns < 0 if @k is before iter pos, > 0 if @k is after */
static inline int __btree_iter_pos_cmp(struct btree_iter *iter,
const struct btree *b,
const struct bkey_packed *k,
bool interior_node)
{
int cmp = bkey_cmp_left_packed(b, k, &iter->pos);
if (cmp)
return cmp;
if (bkey_deleted(k))
return -1;
/*
* Normally, for extents we want the first key strictly greater than
* the iterator position - with the exception that for interior nodes,
* we don't want to advance past the last key if the iterator position
* is POS_MAX:
*/
if (iter->flags & BTREE_ITER_IS_EXTENTS &&
(!interior_node ||
bkey_cmp_left_packed_byval(b, k, POS_MAX)))
return -1;
return 1;
}
static inline int btree_iter_pos_cmp(struct btree_iter *iter,
const struct btree *b,
const struct bkey_packed *k)
{
return __btree_iter_pos_cmp(iter, b, k, b->level != 0);
}
/* Btree node locking: */
/*
* Updates the saved lock sequence number, so that bch2_btree_node_relock() will
* succeed:
*/
void bch2_btree_node_unlock_write(struct btree *b, struct btree_iter *iter)
{
struct btree_iter *linked;
EBUG_ON(iter->l[b->level].b != b);
EBUG_ON(iter->l[b->level].lock_seq + 1 != b->lock.state.seq);
for_each_btree_iter_with_node(iter, b, linked)
linked->l[b->level].lock_seq += 2;
six_unlock_write(&b->lock);
}
void __bch2_btree_node_lock_write(struct btree *b, struct btree_iter *iter)
{
struct bch_fs *c = iter->c;
struct btree_iter *linked;
unsigned readers = 0;
EBUG_ON(btree_node_read_locked(iter, b->level));
for_each_linked_btree_iter(iter, linked)
if (linked->l[b->level].b == b &&
btree_node_read_locked(linked, b->level))
readers++;
/*
* Must drop our read locks before calling six_lock_write() -
* six_unlock() won't do wakeups until the reader count
* goes to 0, and it's safe because we have the node intent
* locked:
*/
atomic64_sub(__SIX_VAL(read_lock, readers),
&b->lock.state.counter);
btree_node_lock_type(c, b, SIX_LOCK_write);
atomic64_add(__SIX_VAL(read_lock, readers),
&b->lock.state.counter);
}
bool __bch2_btree_node_relock(struct btree_iter *iter, unsigned level)
{
struct btree *b = btree_iter_node(iter, level);
int want = __btree_lock_want(iter, level);
if (!b || b == BTREE_ITER_NOT_END)
return false;
if (race_fault())
return false;
if (!six_relock_type(&b->lock, want, iter->l[level].lock_seq) &&
!(iter->l[level].lock_seq >> 1 == b->lock.state.seq >> 1 &&
btree_node_lock_increment(iter, b, level, want)))
return false;
mark_btree_node_locked(iter, level, want);
return true;
}
static bool bch2_btree_node_upgrade(struct btree_iter *iter, unsigned level)
{
struct btree *b = iter->l[level].b;
EBUG_ON(btree_lock_want(iter, level) != BTREE_NODE_INTENT_LOCKED);
if (!is_btree_node(iter, level))
return false;
if (btree_node_intent_locked(iter, level))
return true;
if (race_fault())
return false;
if (btree_node_locked(iter, level)
? six_lock_tryupgrade(&b->lock)
: six_relock_type(&b->lock, SIX_LOCK_intent, iter->l[level].lock_seq))
goto success;
if (iter->l[level].lock_seq >> 1 == b->lock.state.seq >> 1 &&
btree_node_lock_increment(iter, b, level, BTREE_NODE_INTENT_LOCKED)) {
btree_node_unlock(iter, level);
goto success;
}
return false;
success:
mark_btree_node_intent_locked(iter, level);
return true;
}
static inline bool btree_iter_get_locks(struct btree_iter *iter,
bool upgrade)
{
unsigned l = iter->level;
int fail_idx = -1;
do {
if (!btree_iter_node(iter, l))
break;
if (!(upgrade
? bch2_btree_node_upgrade(iter, l)
: bch2_btree_node_relock(iter, l))) {
fail_idx = l;
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
}
l++;
} while (l < iter->locks_want);
/*
* When we fail to get a lock, we have to ensure that any child nodes
* can't be relocked so bch2_btree_iter_traverse has to walk back up to
* the node that we failed to relock:
*/
while (fail_idx >= 0) {
btree_node_unlock(iter, fail_idx);
iter->l[fail_idx].b = BTREE_ITER_NOT_END;
--fail_idx;
}
if (iter->uptodate == BTREE_ITER_NEED_RELOCK)
iter->uptodate = BTREE_ITER_NEED_PEEK;
bch2_btree_iter_verify_locks(iter);
return iter->uptodate < BTREE_ITER_NEED_RELOCK;
}
/* Slowpath: */
bool __bch2_btree_node_lock(struct btree *b, struct bpos pos,
unsigned level,
struct btree_iter *iter,
enum six_lock_type type,
bool may_drop_locks)
{
struct bch_fs *c = iter->c;
struct btree_iter *linked;
bool ret = true;
/* Check if it's safe to block: */
for_each_btree_iter(iter, linked) {
if (!linked->nodes_locked)
continue;
/* * Must lock btree nodes in key order: */
if (__btree_iter_cmp(iter->btree_id, pos, linked) < 0)
ret = false;
/*
* Can't block taking an intent lock if we have _any_ nodes read
* locked:
*
* - Our read lock blocks another thread with an intent lock on
* the same node from getting a write lock, and thus from
* dropping its intent lock
*
* - And the other thread may have multiple nodes intent locked:
* both the node we want to intent lock, and the node we
* already have read locked - deadlock:
*/
if (type == SIX_LOCK_intent &&
linked->nodes_locked != linked->nodes_intent_locked) {
if (may_drop_locks) {
linked->locks_want = max_t(unsigned,
linked->locks_want,
__fls(linked->nodes_locked) + 1);
btree_iter_get_locks(linked, true);
}
ret = false;
}
/*
* Interior nodes must be locked before their descendants: if
* another iterator has possible descendants locked of the node
* we're about to lock, it must have the ancestors locked too:
*/
if (linked->btree_id == iter->btree_id &&
level > __fls(linked->nodes_locked)) {
if (may_drop_locks) {
linked->locks_want =
max(level + 1, max_t(unsigned,
linked->locks_want,
iter->locks_want));
btree_iter_get_locks(linked, true);
}
ret = false;
}
}
if (ret)
__btree_node_lock_type(c, b, type);
else
trans_restart();
return ret;
}
/* Btree iterator locking: */
#ifdef CONFIG_BCACHEFS_DEBUG
void bch2_btree_iter_verify_locks(struct btree_iter *iter)
{
unsigned l;
for (l = 0; btree_iter_node(iter, l); l++) {
if (iter->uptodate >= BTREE_ITER_NEED_RELOCK &&
!btree_node_locked(iter, l))
continue;
BUG_ON(btree_lock_want(iter, l) !=
btree_node_locked_type(iter, l));
}
}
#endif
__flatten
static bool __bch2_btree_iter_relock(struct btree_iter *iter)
{
return iter->uptodate >= BTREE_ITER_NEED_RELOCK
? btree_iter_get_locks(iter, false)
: true;
}
bool bch2_btree_iter_relock(struct btree_iter *iter)
{
struct btree_iter *linked;
bool ret = true;
for_each_btree_iter(iter, linked)
ret &= __bch2_btree_iter_relock(linked);
return ret;
}
bool __bch2_btree_iter_upgrade(struct btree_iter *iter,
unsigned new_locks_want)
{
struct btree_iter *linked;
EBUG_ON(iter->locks_want >= new_locks_want);
iter->locks_want = new_locks_want;
if (btree_iter_get_locks(iter, true))
return true;
/*
* Ancestor nodes must be locked before child nodes, so set locks_want
* on iterators that might lock ancestors before us to avoid getting
* -EINTR later:
*/
for_each_linked_btree_iter(iter, linked)
if (linked->btree_id == iter->btree_id &&
btree_iter_cmp(linked, iter) <= 0 &&
linked->locks_want < new_locks_want) {
linked->locks_want = new_locks_want;
btree_iter_get_locks(linked, true);
}
return false;
}
bool __bch2_btree_iter_upgrade_nounlock(struct btree_iter *iter,
unsigned new_locks_want)
{
unsigned l = iter->level;
EBUG_ON(iter->locks_want >= new_locks_want);
iter->locks_want = new_locks_want;
do {
if (!btree_iter_node(iter, l))
break;
if (!bch2_btree_node_upgrade(iter, l)) {
iter->locks_want = l;
return false;
}
l++;
} while (l < iter->locks_want);
return true;
}
void __bch2_btree_iter_downgrade(struct btree_iter *iter,
unsigned downgrade_to)
{
struct btree_iter *linked;
unsigned l;
/*
* We downgrade linked iterators as well because btree_iter_upgrade
* might have had to modify locks_want on linked iterators due to lock
* ordering:
*/
for_each_btree_iter(iter, linked) {
unsigned new_locks_want = downgrade_to ?:
(linked->flags & BTREE_ITER_INTENT ? 1 : 0);
if (linked->locks_want <= new_locks_want)
continue;
linked->locks_want = new_locks_want;
while (linked->nodes_locked &&
(l = __fls(linked->nodes_locked)) >= linked->locks_want) {
if (l > linked->level) {
btree_node_unlock(linked, l);
} else {
if (btree_node_intent_locked(linked, l)) {
six_lock_downgrade(&linked->l[l].b->lock);
linked->nodes_intent_locked ^= 1 << l;
}
break;
}
}
bch2_btree_iter_verify_locks(linked);
}
}
int bch2_btree_iter_unlock(struct btree_iter *iter)
{
struct btree_iter *linked;
for_each_btree_iter(iter, linked)
__bch2_btree_iter_unlock(linked);
return iter->flags & BTREE_ITER_ERROR ? -EIO : 0;
}
/* Btree iterator: */
#ifdef CONFIG_BCACHEFS_DEBUG
static void __bch2_btree_iter_verify(struct btree_iter *iter,
struct btree *b)
{
struct btree_iter_level *l = &iter->l[b->level];
struct btree_node_iter tmp = l->iter;
struct bkey_packed *k;
if (iter->uptodate > BTREE_ITER_NEED_PEEK)
return;
bch2_btree_node_iter_verify(&l->iter, b);
/*
* For interior nodes, the iterator will have skipped past
* deleted keys:
*
* For extents, the iterator may have skipped past deleted keys (but not
* whiteouts)
*/
k = b->level || iter->flags & BTREE_ITER_IS_EXTENTS
? bch2_btree_node_iter_prev_filter(&tmp, b, KEY_TYPE_DISCARD)
: bch2_btree_node_iter_prev_all(&tmp, b);
if (k && btree_iter_pos_cmp(iter, b, k) > 0) {
char buf[100];
struct bkey uk = bkey_unpack_key(b, k);
bch2_bkey_to_text(&PBUF(buf), &uk);
panic("prev key should be before iter pos:\n%s\n%llu:%llu\n",
buf, iter->pos.inode, iter->pos.offset);
}
k = bch2_btree_node_iter_peek_all(&l->iter, b);
if (k && btree_iter_pos_cmp(iter, b, k) < 0) {
char buf[100];
struct bkey uk = bkey_unpack_key(b, k);
bch2_bkey_to_text(&PBUF(buf), &uk);
panic("iter should be after current key:\n"
"iter pos %llu:%llu\n"
"cur key %s\n",
iter->pos.inode, iter->pos.offset, buf);
}
BUG_ON(iter->uptodate == BTREE_ITER_UPTODATE &&
(iter->flags & BTREE_ITER_TYPE) == BTREE_ITER_KEYS &&
!bkey_whiteout(&iter->k) &&
bch2_btree_node_iter_end(&l->iter));
}
void bch2_btree_iter_verify(struct btree_iter *iter, struct btree *b)
{
struct btree_iter *linked;
for_each_btree_iter_with_node(iter, b, linked)
__bch2_btree_iter_verify(linked, b);
}
#else
static inline void __bch2_btree_iter_verify(struct btree_iter *iter,
struct btree *b) {}
#endif
static void __bch2_btree_node_iter_fix(struct btree_iter *iter,
struct btree *b,
struct btree_node_iter *node_iter,
struct bset_tree *t,
struct bkey_packed *where,
unsigned clobber_u64s,
unsigned new_u64s)
{
const struct bkey_packed *end = btree_bkey_last(b, t);
struct btree_node_iter_set *set;
unsigned offset = __btree_node_key_to_offset(b, where);
int shift = new_u64s - clobber_u64s;
unsigned old_end = t->end_offset - shift;
btree_node_iter_for_each(node_iter, set)
if (set->end == old_end)
goto found;
/* didn't find the bset in the iterator - might have to readd it: */
if (new_u64s &&
btree_iter_pos_cmp(iter, b, where) > 0) {
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
bch2_btree_node_iter_push(node_iter, b, where, end);
if (!b->level &&
node_iter == &iter->l[0].iter)
bkey_disassemble(b,
bch2_btree_node_iter_peek_all(node_iter, b),
&iter->k);
}
return;
found:
set->end = t->end_offset;
/* Iterator hasn't gotten to the key that changed yet: */
if (set->k < offset)
return;
if (new_u64s &&
btree_iter_pos_cmp(iter, b, where) > 0) {
set->k = offset;
} else if (set->k < offset + clobber_u64s) {
set->k = offset + new_u64s;
if (set->k == set->end)
bch2_btree_node_iter_set_drop(node_iter, set);
} else {
set->k = (int) set->k + shift;
goto iter_current_key_not_modified;
}
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
bch2_btree_node_iter_sort(node_iter, b);
if (!b->level && node_iter == &iter->l[0].iter)
__btree_iter_peek_all(iter, &iter->l[0], &iter->k);
iter_current_key_not_modified:
/*
* Interior nodes are special because iterators for interior nodes don't
* obey the usual invariants regarding the iterator position:
*
* We may have whiteouts that compare greater than the iterator
* position, and logically should be in the iterator, but that we
* skipped past to find the first live key greater than the iterator
* position. This becomes an issue when we insert a new key that is
* greater than the current iterator position, but smaller than the
* whiteouts we've already skipped past - this happens in the course of
* a btree split.
*
* We have to rewind the iterator past to before those whiteouts here,
* else bkey_node_iter_prev() is not going to work and who knows what
* else would happen. And we have to do it manually, because here we've
* already done the insert and the iterator is currently inconsistent:
*
* We've got multiple competing invariants, here - we have to be careful
* about rewinding iterators for interior nodes, because they should
* always point to the key for the child node the btree iterator points
* to.
*/
if (b->level && new_u64s &&
btree_iter_pos_cmp(iter, b, where) > 0) {
struct bset_tree *t, *where_set = bch2_bkey_to_bset_inlined(b, where);
struct bkey_packed *k;
for_each_bset(b, t) {
if (where_set == t)
continue;
k = bch2_bkey_prev_all(b, t,
bch2_btree_node_iter_bset_pos(node_iter, b, t));
if (k &&
bkey_iter_cmp(b, k, where) > 0) {
struct btree_node_iter_set *set;
unsigned offset =
__btree_node_key_to_offset(b, bkey_next(k));
btree_node_iter_for_each(node_iter, set)
if (set->k == offset) {
set->k = __btree_node_key_to_offset(b, k);
bch2_btree_node_iter_sort(node_iter, b);
goto next_bset;
}
bch2_btree_node_iter_push(node_iter, b, k,
btree_bkey_last(b, t));
}
next_bset:
t = t;
}
}
}
void bch2_btree_node_iter_fix(struct btree_iter *iter,
struct btree *b,
struct btree_node_iter *node_iter,
struct bkey_packed *where,
unsigned clobber_u64s,
unsigned new_u64s)
{
struct bset_tree *t = bch2_bkey_to_bset_inlined(b, where);
struct btree_iter *linked;
if (node_iter != &iter->l[b->level].iter)
__bch2_btree_node_iter_fix(iter, b, node_iter, t,
where, clobber_u64s, new_u64s);
for_each_btree_iter_with_node(iter, b, linked)
__bch2_btree_node_iter_fix(linked, b,
&linked->l[b->level].iter, t,
where, clobber_u64s, new_u64s);
}
static inline struct bkey_s_c __btree_iter_unpack(struct btree_iter *iter,
struct btree_iter_level *l,
struct bkey *u,
struct bkey_packed *k)
{
struct bkey_s_c ret;
if (unlikely(!k)) {
/*
* signal to bch2_btree_iter_peek_slot() that we're currently at
* a hole
*/
u->type = KEY_TYPE_DELETED;
return bkey_s_c_null;
}
ret = bkey_disassemble(l->b, k, u);
if (debug_check_bkeys(iter->c))
bch2_bkey_debugcheck(iter->c, l->b, ret);
return ret;
}
/* peek_all() doesn't skip deleted keys */
static inline struct bkey_s_c __btree_iter_peek_all(struct btree_iter *iter,
struct btree_iter_level *l,
struct bkey *u)
{
return __btree_iter_unpack(iter, l, u,
bch2_btree_node_iter_peek_all(&l->iter, l->b));
}
static inline struct bkey_s_c __btree_iter_peek(struct btree_iter *iter,
struct btree_iter_level *l)
{
return __btree_iter_unpack(iter, l, &iter->k,
bch2_btree_node_iter_peek(&l->iter, l->b));
}
static inline bool btree_iter_advance_to_pos(struct btree_iter *iter,
struct btree_iter_level *l,
int max_advance)
{
struct bkey_packed *k;
int nr_advanced = 0;
while ((k = bch2_btree_node_iter_peek_all(&l->iter, l->b)) &&
btree_iter_pos_cmp(iter, l->b, k) < 0) {
if (max_advance > 0 && nr_advanced >= max_advance)
return false;
bch2_btree_node_iter_advance(&l->iter, l->b);
nr_advanced++;
}
return true;
}
/*
* Verify that iterator for parent node points to child node:
*/
static void btree_iter_verify_new_node(struct btree_iter *iter, struct btree *b)
{
struct btree_iter_level *l;
unsigned plevel;
bool parent_locked;
struct bkey_packed *k;
if (!IS_ENABLED(CONFIG_BCACHEFS_DEBUG))
return;
plevel = b->level + 1;
if (!btree_iter_node(iter, plevel))
return;
parent_locked = btree_node_locked(iter, plevel);
if (!bch2_btree_node_relock(iter, plevel))
return;
l = &iter->l[plevel];
k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
if (!k ||
bkey_deleted(k) ||
bkey_cmp_left_packed(l->b, k, &b->key.k.p)) {
char buf[100];
struct bkey uk = bkey_unpack_key(b, k);
bch2_bkey_to_text(&PBUF(buf), &uk);
panic("parent iter doesn't point to new node:\n%s\n%llu:%llu\n",
buf, b->key.k.p.inode, b->key.k.p.offset);
}
if (!parent_locked)
btree_node_unlock(iter, b->level + 1);
}
static inline bool btree_iter_pos_after_node(struct btree_iter *iter,
struct btree *b)
{
return __btree_iter_pos_cmp(iter, NULL,
bkey_to_packed(&b->key), true) < 0;
}
static inline bool btree_iter_pos_in_node(struct btree_iter *iter,
struct btree *b)
{
return iter->btree_id == b->btree_id &&
bkey_cmp(iter->pos, b->data->min_key) >= 0 &&
!btree_iter_pos_after_node(iter, b);
}
static inline void __btree_iter_init(struct btree_iter *iter,
unsigned level)
{
struct btree_iter_level *l = &iter->l[level];
bch2_btree_node_iter_init(&l->iter, l->b, &iter->pos);
if (iter->flags & BTREE_ITER_IS_EXTENTS)
btree_iter_advance_to_pos(iter, l, -1);
/* Skip to first non whiteout: */
if (level)
bch2_btree_node_iter_peek(&l->iter, l->b);
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
}
static inline void btree_iter_node_set(struct btree_iter *iter,
struct btree *b)
{
btree_iter_verify_new_node(iter, b);
EBUG_ON(!btree_iter_pos_in_node(iter, b));
EBUG_ON(b->lock.state.seq & 1);
iter->l[b->level].lock_seq = b->lock.state.seq;
iter->l[b->level].b = b;
__btree_iter_init(iter, b->level);
}
/*
* A btree node is being replaced - update the iterator to point to the new
* node:
*/
void bch2_btree_iter_node_replace(struct btree_iter *iter, struct btree *b)
{
enum btree_node_locked_type t;
struct btree_iter *linked;
for_each_btree_iter(iter, linked)
if (btree_iter_pos_in_node(linked, b)) {
/*
* bch2_btree_iter_node_drop() has already been called -
* the old node we're replacing has already been
* unlocked and the pointer invalidated
*/
BUG_ON(btree_node_locked(linked, b->level));
t = btree_lock_want(linked, b->level);
if (t != BTREE_NODE_UNLOCKED) {
six_lock_increment(&b->lock, (enum six_lock_type) t);
mark_btree_node_locked(linked, b->level, (enum six_lock_type) t);
}
btree_iter_node_set(linked, b);
}
six_unlock_intent(&b->lock);
}
void bch2_btree_iter_node_drop(struct btree_iter *iter, struct btree *b)
{
struct btree_iter *linked;
unsigned level = b->level;
for_each_btree_iter(iter, linked)
if (linked->l[level].b == b) {
btree_node_unlock(linked, level);
linked->l[level].b = BTREE_ITER_NOT_END;
}
}
/*
* A btree node has been modified in such a way as to invalidate iterators - fix
* them:
*/
void bch2_btree_iter_reinit_node(struct btree_iter *iter, struct btree *b)
{
struct btree_iter *linked;
for_each_btree_iter_with_node(iter, b, linked)
__btree_iter_init(linked, b->level);
}
static inline int btree_iter_lock_root(struct btree_iter *iter,
unsigned depth_want)
{
struct bch_fs *c = iter->c;
struct btree *b;
enum six_lock_type lock_type;
unsigned i;
EBUG_ON(iter->nodes_locked);
while (1) {
b = READ_ONCE(c->btree_roots[iter->btree_id].b);
iter->level = READ_ONCE(b->level);
if (unlikely(iter->level < depth_want)) {
/*
* the root is at a lower depth than the depth we want:
* got to the end of the btree, or we're walking nodes
* greater than some depth and there are no nodes >=
* that depth
*/
iter->level = depth_want;
iter->l[iter->level].b = NULL;
return 0;
}
lock_type = __btree_lock_want(iter, iter->level);
if (unlikely(!btree_node_lock(b, POS_MAX, iter->level,
iter, lock_type, true)))
return -EINTR;
if (likely(b == c->btree_roots[iter->btree_id].b &&
b->level == iter->level &&
!race_fault())) {
for (i = 0; i < iter->level; i++)
iter->l[i].b = BTREE_ITER_NOT_END;
iter->l[iter->level].b = b;
mark_btree_node_locked(iter, iter->level, lock_type);
btree_iter_node_set(iter, b);
return 0;
}
six_unlock_type(&b->lock, lock_type);
}
}
noinline
static void btree_iter_prefetch(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[iter->level];
struct btree_node_iter node_iter = l->iter;
struct bkey_packed *k;
BKEY_PADDED(k) tmp;
unsigned nr = test_bit(BCH_FS_STARTED, &iter->c->flags)
? (iter->level > 1 ? 0 : 2)
: (iter->level > 1 ? 1 : 16);
bool was_locked = btree_node_locked(iter, iter->level);
while (nr) {
if (!bch2_btree_node_relock(iter, iter->level))
return;
bch2_btree_node_iter_advance(&node_iter, l->b);
k = bch2_btree_node_iter_peek(&node_iter, l->b);
if (!k)
break;
bch2_bkey_unpack(l->b, &tmp.k, k);
bch2_btree_node_prefetch(iter->c, iter, &tmp.k,
iter->level - 1);
}
if (!was_locked)
btree_node_unlock(iter, iter->level);
}
static inline int btree_iter_down(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[iter->level];
struct btree *b;
unsigned level = iter->level - 1;
enum six_lock_type lock_type = __btree_lock_want(iter, level);
BKEY_PADDED(k) tmp;
BUG_ON(!btree_node_locked(iter, iter->level));
bch2_bkey_unpack(l->b, &tmp.k,
bch2_btree_node_iter_peek(&l->iter, l->b));
b = bch2_btree_node_get(iter->c, iter, &tmp.k, level, lock_type, true);
if (unlikely(IS_ERR(b)))
return PTR_ERR(b);
mark_btree_node_locked(iter, level, lock_type);
btree_iter_node_set(iter, b);
if (iter->flags & BTREE_ITER_PREFETCH)
btree_iter_prefetch(iter);
iter->level = level;
return 0;
}
static void btree_iter_up(struct btree_iter *iter)
{
btree_node_unlock(iter, iter->level++);
}
int __must_check __bch2_btree_iter_traverse(struct btree_iter *);
static int btree_iter_traverse_error(struct btree_iter *iter, int ret)
{
struct bch_fs *c = iter->c;
struct btree_iter *linked, *sorted_iters, **i;
retry_all:
bch2_btree_iter_unlock(iter);
if (ret != -ENOMEM && ret != -EINTR)
goto io_error;
if (ret == -ENOMEM) {
struct closure cl;
closure_init_stack(&cl);
do {
ret = bch2_btree_cache_cannibalize_lock(c, &cl);
closure_sync(&cl);
} while (ret);
}
/*
* Linked iters are normally a circular singly linked list - break cycle
* while we sort them:
*/
linked = iter->next;
iter->next = NULL;
sorted_iters = NULL;
while (linked) {
iter = linked;
linked = linked->next;
i = &sorted_iters;
while (*i && btree_iter_cmp(iter, *i) > 0)
i = &(*i)->next;
iter->next = *i;
*i = iter;
}
/* Make list circular again: */
iter = sorted_iters;
while (iter->next)
iter = iter->next;
iter->next = sorted_iters;
/* Now, redo traversals in correct order: */
iter = sorted_iters;
do {
retry:
ret = __bch2_btree_iter_traverse(iter);
if (unlikely(ret)) {
if (ret == -EINTR)
goto retry;
goto retry_all;
}
iter = iter->next;
} while (iter != sorted_iters);
ret = btree_iter_linked(iter) ? -EINTR : 0;
out:
bch2_btree_cache_cannibalize_unlock(c);
return ret;
io_error:
BUG_ON(ret != -EIO);
iter->flags |= BTREE_ITER_ERROR;
iter->l[iter->level].b = BTREE_ITER_NOT_END;
goto out;
}
static unsigned btree_iter_up_until_locked(struct btree_iter *iter,
bool check_pos)
{
unsigned l = iter->level;
while (btree_iter_node(iter, l) &&
!(is_btree_node(iter, l) &&
bch2_btree_node_relock(iter, l) &&
(!check_pos ||
btree_iter_pos_in_node(iter, iter->l[l].b)))) {
btree_node_unlock(iter, l);
iter->l[l].b = BTREE_ITER_NOT_END;
l++;
}
return l;
}
/*
* This is the main state machine for walking down the btree - walks down to a
* specified depth
*
* Returns 0 on success, -EIO on error (error reading in a btree node).
*
* On error, caller (peek_node()/peek_key()) must return NULL; the error is
* stashed in the iterator and returned from bch2_btree_iter_unlock().
*/
int __must_check __bch2_btree_iter_traverse(struct btree_iter *iter)
{
unsigned depth_want = iter->level;
if (unlikely(iter->level >= BTREE_MAX_DEPTH))
return 0;
if (__bch2_btree_iter_relock(iter))
return 0;
/*
* XXX: correctly using BTREE_ITER_UPTODATE should make using check_pos
* here unnecessary
*/
iter->level = btree_iter_up_until_locked(iter, true);
/*
* If we've got a btree node locked (i.e. we aren't about to relock the
* root) - advance its node iterator if necessary:
*
* XXX correctly using BTREE_ITER_UPTODATE should make this unnecessary
*/
if (btree_iter_node(iter, iter->level))
btree_iter_advance_to_pos(iter, &iter->l[iter->level], -1);
/*
* Note: iter->nodes[iter->level] may be temporarily NULL here - that
* would indicate to other code that we got to the end of the btree,
* here it indicates that relocking the root failed - it's critical that
* btree_iter_lock_root() comes next and that it can't fail
*/
while (iter->level > depth_want) {
int ret = btree_iter_node(iter, iter->level)
? btree_iter_down(iter)
: btree_iter_lock_root(iter, depth_want);
if (unlikely(ret)) {
iter->level = depth_want;
iter->l[iter->level].b = BTREE_ITER_NOT_END;
return ret;
}
}
iter->uptodate = BTREE_ITER_NEED_PEEK;
bch2_btree_iter_verify_locks(iter);
__bch2_btree_iter_verify(iter, iter->l[iter->level].b);
return 0;
}
int __must_check bch2_btree_iter_traverse(struct btree_iter *iter)
{
int ret;
ret = __bch2_btree_iter_traverse(iter);
if (unlikely(ret))
ret = btree_iter_traverse_error(iter, ret);
BUG_ON(ret == -EINTR && !btree_iter_linked(iter));
return ret;
}
static inline void bch2_btree_iter_checks(struct btree_iter *iter,
enum btree_iter_type type)
{
EBUG_ON(iter->btree_id >= BTREE_ID_NR);
EBUG_ON(!!(iter->flags & BTREE_ITER_IS_EXTENTS) !=
(iter->btree_id == BTREE_ID_EXTENTS &&
type != BTREE_ITER_NODES));
bch2_btree_iter_verify_locks(iter);
}
/* Iterate across nodes (leaf and interior nodes) */
struct btree *bch2_btree_iter_peek_node(struct btree_iter *iter)
{
struct btree *b;
int ret;
bch2_btree_iter_checks(iter, BTREE_ITER_NODES);
if (iter->uptodate == BTREE_ITER_UPTODATE)
return iter->l[iter->level].b;
ret = bch2_btree_iter_traverse(iter);
if (ret)
return NULL;
b = btree_iter_node(iter, iter->level);
if (!b)
return NULL;
BUG_ON(bkey_cmp(b->key.k.p, iter->pos) < 0);
iter->pos = b->key.k.p;
iter->uptodate = BTREE_ITER_UPTODATE;
return b;
}
struct btree *bch2_btree_iter_next_node(struct btree_iter *iter, unsigned depth)
{
struct btree *b;
int ret;
bch2_btree_iter_checks(iter, BTREE_ITER_NODES);
/* already got to end? */
if (!btree_iter_node(iter, iter->level))
return NULL;
btree_iter_up(iter);
if (!bch2_btree_node_relock(iter, iter->level))
btree_iter_set_dirty(iter, BTREE_ITER_NEED_RELOCK);
ret = bch2_btree_iter_traverse(iter);
if (ret)
return NULL;
/* got to end? */
b = btree_iter_node(iter, iter->level);
if (!b)
return NULL;
if (bkey_cmp(iter->pos, b->key.k.p) < 0) {
/*
* Haven't gotten to the end of the parent node: go back down to
* the next child node
*/
/*
* We don't really want to be unlocking here except we can't
* directly tell btree_iter_traverse() "traverse to this level"
* except by setting iter->level, so we have to unlock so we
* don't screw up our lock invariants:
*/
if (btree_node_read_locked(iter, iter->level))
btree_node_unlock(iter, iter->level);
/* ick: */
iter->pos = iter->btree_id == BTREE_ID_INODES
? btree_type_successor(iter->btree_id, iter->pos)
: bkey_successor(iter->pos);
iter->level = depth;
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
ret = bch2_btree_iter_traverse(iter);
if (ret)
return NULL;
b = iter->l[iter->level].b;
}
iter->pos = b->key.k.p;
iter->uptodate = BTREE_ITER_UPTODATE;
return b;
}
/* Iterate across keys (in leaf nodes only) */
void bch2_btree_iter_set_pos_same_leaf(struct btree_iter *iter, struct bpos new_pos)
{
struct btree_iter_level *l = &iter->l[0];
EBUG_ON(iter->level != 0);
EBUG_ON(bkey_cmp(new_pos, iter->pos) < 0);
EBUG_ON(!btree_node_locked(iter, 0));
EBUG_ON(bkey_cmp(new_pos, l->b->key.k.p) > 0);
iter->pos = new_pos;
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
btree_iter_advance_to_pos(iter, l, -1);
if (bch2_btree_node_iter_end(&l->iter) &&
btree_iter_pos_after_node(iter, l->b))
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
}
void bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
{
int cmp = bkey_cmp(new_pos, iter->pos);
unsigned level;
if (!cmp)
return;
iter->pos = new_pos;
level = btree_iter_up_until_locked(iter, true);
if (btree_iter_node(iter, level)) {
/*
* We might have to skip over many keys, or just a few: try
* advancing the node iterator, and if we have to skip over too
* many keys just reinit it (or if we're rewinding, since that
* is expensive).
*/
if (cmp < 0 ||
!btree_iter_advance_to_pos(iter, &iter->l[level], 8))
__btree_iter_init(iter, level);
/* Don't leave it locked if we're not supposed to: */
if (btree_lock_want(iter, level) == BTREE_NODE_UNLOCKED)
btree_node_unlock(iter, level);
}
if (level != iter->level)
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
else
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
}
static inline struct bkey_s_c btree_iter_peek_uptodate(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct bkey_s_c ret = { .k = &iter->k };
if (!bkey_deleted(&iter->k)) {
EBUG_ON(bch2_btree_node_iter_end(&l->iter));
ret.v = bkeyp_val(&l->b->format,
__bch2_btree_node_iter_peek_all(&l->iter, l->b));
}
if (debug_check_bkeys(iter->c) &&
!bkey_deleted(ret.k))
bch2_bkey_debugcheck(iter->c, l->b, ret);
return ret;
}
struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct bkey_s_c k;
int ret;
bch2_btree_iter_checks(iter, BTREE_ITER_KEYS);
if (iter->uptodate == BTREE_ITER_UPTODATE)
return btree_iter_peek_uptodate(iter);
while (1) {
ret = bch2_btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
k = __btree_iter_peek(iter, l);
if (likely(k.k))
break;
/* got to the end of the leaf, iterator needs to be traversed: */
iter->pos = l->b->key.k.p;
iter->uptodate = BTREE_ITER_NEED_TRAVERSE;
if (!bkey_cmp(iter->pos, POS_MAX))
return bkey_s_c_null;
iter->pos = btree_type_successor(iter->btree_id, iter->pos);
}
/*
* iter->pos should always be equal to the key we just
* returned - except extents can straddle iter->pos:
*/
if (!(iter->flags & BTREE_ITER_IS_EXTENTS) ||
bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0)
iter->pos = bkey_start_pos(k.k);
iter->uptodate = BTREE_ITER_UPTODATE;
return k;
}
static noinline
struct bkey_s_c bch2_btree_iter_peek_next_leaf(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
iter->pos = l->b->key.k.p;
iter->uptodate = BTREE_ITER_NEED_TRAVERSE;
if (!bkey_cmp(iter->pos, POS_MAX))
return bkey_s_c_null;
iter->pos = btree_type_successor(iter->btree_id, iter->pos);
return bch2_btree_iter_peek(iter);
}
struct bkey_s_c bch2_btree_iter_next(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct bkey_packed *p;
struct bkey_s_c k;
bch2_btree_iter_checks(iter, BTREE_ITER_KEYS);
if (unlikely(iter->uptodate != BTREE_ITER_UPTODATE)) {
k = bch2_btree_iter_peek(iter);
if (IS_ERR_OR_NULL(k.k))
return k;
}
do {
bch2_btree_node_iter_advance(&l->iter, l->b);
p = bch2_btree_node_iter_peek_all(&l->iter, l->b);
if (unlikely(!p))
return bch2_btree_iter_peek_next_leaf(iter);
} while (bkey_whiteout(p));
k = __btree_iter_unpack(iter, l, &iter->k, p);
EBUG_ON(bkey_cmp(bkey_start_pos(k.k), iter->pos) < 0);
iter->pos = bkey_start_pos(k.k);
return k;
}
struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct bkey_packed *p;
struct bkey_s_c k;
int ret;
bch2_btree_iter_checks(iter, BTREE_ITER_KEYS);
if (unlikely(iter->uptodate != BTREE_ITER_UPTODATE)) {
k = bch2_btree_iter_peek(iter);
if (IS_ERR(k.k))
return k;
}
while (1) {
p = bch2_btree_node_iter_prev(&l->iter, l->b);
if (likely(p))
break;
iter->pos = l->b->data->min_key;
if (!bkey_cmp(iter->pos, POS_MIN))
return bkey_s_c_null;
bch2_btree_iter_set_pos(iter,
btree_type_predecessor(iter->btree_id, iter->pos));
ret = bch2_btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
p = bch2_btree_node_iter_peek(&l->iter, l->b);
if (p)
break;
}
k = __btree_iter_unpack(iter, l, &iter->k, p);
EBUG_ON(bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0);
iter->pos = bkey_start_pos(k.k);
iter->uptodate = BTREE_ITER_UPTODATE;
return k;
}
static inline struct bkey_s_c
__bch2_btree_iter_peek_slot_extents(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct btree_node_iter node_iter;
struct bkey_s_c k;
struct bkey n;
int ret;
recheck:
while ((k = __btree_iter_peek_all(iter, l, &iter->k)).k &&
bkey_deleted(k.k) &&
bkey_cmp(bkey_start_pos(k.k), iter->pos) == 0)
bch2_btree_node_iter_advance(&l->iter, l->b);
/*
* iterator is now at the correct position for inserting at iter->pos,
* but we need to keep iterating until we find the first non whiteout so
* we know how big a hole we have, if any:
*/
node_iter = l->iter;
if (k.k && bkey_whiteout(k.k))
k = __btree_iter_unpack(iter, l, &iter->k,
bch2_btree_node_iter_peek(&node_iter, l->b));
/*
* If we got to the end of the node, check if we need to traverse to the
* next node:
*/
if (unlikely(!k.k && btree_iter_pos_after_node(iter, l->b))) {
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
ret = bch2_btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
goto recheck;
}
if (k.k &&
!bkey_whiteout(k.k) &&
bkey_cmp(bkey_start_pos(k.k), iter->pos) <= 0) {
/*
* if we skipped forward to find the first non whiteout and
* there _wasn't_ actually a hole, we want the iterator to be
* pointed at the key we found:
*/
l->iter = node_iter;
EBUG_ON(bkey_cmp(k.k->p, iter->pos) < 0);
EBUG_ON(bkey_deleted(k.k));
iter->uptodate = BTREE_ITER_UPTODATE;
return k;
}
/* hole */
/* holes can't span inode numbers: */
if (iter->pos.offset == KEY_OFFSET_MAX) {
if (iter->pos.inode == KEY_INODE_MAX)
return bkey_s_c_null;
iter->pos = bkey_successor(iter->pos);
goto recheck;
}
if (!k.k)
k.k = &l->b->key.k;
bkey_init(&n);
n.p = iter->pos;
bch2_key_resize(&n,
min_t(u64, KEY_SIZE_MAX,
(k.k->p.inode == n.p.inode
? bkey_start_offset(k.k)
: KEY_OFFSET_MAX) -
n.p.offset));
EBUG_ON(!n.size);
iter->k = n;
iter->uptodate = BTREE_ITER_UPTODATE;
return (struct bkey_s_c) { &iter->k, NULL };
}
static inline struct bkey_s_c
__bch2_btree_iter_peek_slot(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct bkey_s_c k;
int ret;
if (iter->flags & BTREE_ITER_IS_EXTENTS)
return __bch2_btree_iter_peek_slot_extents(iter);
recheck:
while ((k = __btree_iter_peek_all(iter, l, &iter->k)).k &&
bkey_deleted(k.k) &&
bkey_cmp(k.k->p, iter->pos) == 0)
bch2_btree_node_iter_advance(&l->iter, l->b);
/*
* If we got to the end of the node, check if we need to traverse to the
* next node:
*/
if (unlikely(!k.k && btree_iter_pos_after_node(iter, l->b))) {
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
ret = bch2_btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
goto recheck;
}
if (k.k &&
!bkey_deleted(k.k) &&
!bkey_cmp(iter->pos, k.k->p)) {
iter->uptodate = BTREE_ITER_UPTODATE;
return k;
} else {
/* hole */
bkey_init(&iter->k);
iter->k.p = iter->pos;
iter->uptodate = BTREE_ITER_UPTODATE;
return (struct bkey_s_c) { &iter->k, NULL };
}
}
struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)
{
int ret;
bch2_btree_iter_checks(iter, BTREE_ITER_SLOTS);
if (iter->uptodate == BTREE_ITER_UPTODATE)
return btree_iter_peek_uptodate(iter);
ret = bch2_btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
return __bch2_btree_iter_peek_slot(iter);
}
struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *iter)
{
bch2_btree_iter_checks(iter, BTREE_ITER_SLOTS);
iter->pos = btree_type_successor(iter->btree_id, iter->k.p);
if (unlikely(iter->uptodate != BTREE_ITER_UPTODATE)) {
/*
* XXX: when we just need to relock we should be able to avoid
* calling traverse, but we need to kill BTREE_ITER_NEED_PEEK
* for that to work
*/
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
return bch2_btree_iter_peek_slot(iter);
}
if (!bkey_deleted(&iter->k))
bch2_btree_node_iter_advance(&iter->l[0].iter, iter->l[0].b);
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
return __bch2_btree_iter_peek_slot(iter);
}
void __bch2_btree_iter_init(struct btree_iter *iter, struct bch_fs *c,
enum btree_id btree_id, struct bpos pos,
unsigned locks_want, unsigned depth,
unsigned flags)
{
unsigned i;
EBUG_ON(depth >= BTREE_MAX_DEPTH);
EBUG_ON(locks_want > BTREE_MAX_DEPTH);
iter->c = c;
iter->pos = pos;
bkey_init(&iter->k);
iter->k.p = pos;
iter->flags = flags;
iter->uptodate = BTREE_ITER_NEED_TRAVERSE;
iter->btree_id = btree_id;
iter->level = depth;
iter->locks_want = locks_want;
iter->nodes_locked = 0;
iter->nodes_intent_locked = 0;
for (i = 0; i < ARRAY_SIZE(iter->l); i++)
iter->l[i].b = NULL;
iter->l[iter->level].b = BTREE_ITER_NOT_END;
iter->next = iter;
prefetch(c->btree_roots[btree_id].b);
}
void bch2_btree_iter_unlink(struct btree_iter *iter)
{
struct btree_iter *linked;
__bch2_btree_iter_unlock(iter);
if (!btree_iter_linked(iter))
return;
for_each_linked_btree_iter(iter, linked)
if (linked->next == iter) {
linked->next = iter->next;
iter->next = iter;
return;
}
BUG();
}
void bch2_btree_iter_link(struct btree_iter *iter, struct btree_iter *new)
{
BUG_ON(btree_iter_linked(new));
new->next = iter->next;
iter->next = new;
}
void bch2_btree_iter_copy(struct btree_iter *dst, struct btree_iter *src)
{
unsigned i;
__bch2_btree_iter_unlock(dst);
memcpy(dst, src, offsetof(struct btree_iter, next));
for (i = 0; i < BTREE_MAX_DEPTH; i++)
if (btree_node_locked(dst, i))
six_lock_increment(&dst->l[i].b->lock,
__btree_lock_want(dst, i));
}
/* new transactional stuff: */
static void btree_trans_verify(struct btree_trans *trans)
{
unsigned i;
for (i = 0; i < trans->nr_iters; i++) {
struct btree_iter *iter = &trans->iters[i];
BUG_ON(btree_iter_linked(iter) !=
((trans->iters_linked & (1 << i)) &&
!is_power_of_2(trans->iters_linked)));
}
}
static inline unsigned btree_trans_iter_idx(struct btree_trans *trans,
struct btree_iter *iter)
{
ssize_t idx = iter - trans->iters;
BUG_ON(idx < 0 || idx >= trans->nr_iters);
BUG_ON(!(trans->iters_live & (1U << idx)));
return idx;
}
void bch2_trans_iter_put(struct btree_trans *trans,
struct btree_iter *iter)
{
ssize_t idx = btree_trans_iter_idx(trans, iter);
trans->iters_live &= ~(1U << idx);
}
void bch2_trans_iter_free(struct btree_trans *trans,
struct btree_iter *iter)
{
ssize_t idx = btree_trans_iter_idx(trans, iter);
trans->iters_live &= ~(1U << idx);
trans->iters_linked &= ~(1U << idx);
bch2_btree_iter_unlink(iter);
}
static int btree_trans_realloc_iters(struct btree_trans *trans)
{
struct btree_iter *new_iters;
unsigned i;
bch2_trans_unlock(trans);
new_iters = mempool_alloc(&trans->c->btree_iters_pool, GFP_NOFS);
memcpy(new_iters, trans->iters,
sizeof(struct btree_iter) * trans->nr_iters);
trans->iters = new_iters;
for (i = 0; i < trans->nr_iters; i++)
trans->iters[i].next = &trans->iters[i];
if (trans->iters_linked) {
unsigned first_linked = __ffs(trans->iters_linked);
for (i = first_linked + 1; i < trans->nr_iters; i++)
if (trans->iters_linked & (1 << i))
bch2_btree_iter_link(&trans->iters[first_linked],
&trans->iters[i]);
}
btree_trans_verify(trans);
if (trans->iters_live) {
trans_restart();
return -EINTR;
}
return 0;
}
void bch2_trans_preload_iters(struct btree_trans *trans)
{
if (trans->iters == trans->iters_onstack)
btree_trans_realloc_iters(trans);
}
static struct btree_iter *__btree_trans_get_iter(struct btree_trans *trans,
unsigned btree_id,
unsigned flags, u64 iter_id)
{
struct btree_iter *iter;
int idx;
BUG_ON(trans->nr_iters > BTREE_ITER_MAX);
for (idx = 0; idx < trans->nr_iters; idx++)
if (trans->iter_ids[idx] == iter_id)
goto found;
idx = -1;
found:
if (idx < 0) {
idx = ffz(trans->iters_linked);
if (idx < trans->nr_iters)
goto got_slot;
BUG_ON(trans->nr_iters == BTREE_ITER_MAX);
if (trans->iters == trans->iters_onstack &&
trans->nr_iters == ARRAY_SIZE(trans->iters_onstack)) {
int ret = btree_trans_realloc_iters(trans);
if (ret)
return ERR_PTR(ret);
}
idx = trans->nr_iters++;
got_slot:
trans->iter_ids[idx] = iter_id;
iter = &trans->iters[idx];
bch2_btree_iter_init(iter, trans->c, btree_id, POS_MIN, flags);
} else {
iter = &trans->iters[idx];
iter->flags &= ~(BTREE_ITER_INTENT|BTREE_ITER_PREFETCH);
iter->flags |= flags & (BTREE_ITER_INTENT|BTREE_ITER_PREFETCH);
}
BUG_ON(trans->iters_live & (1 << idx));
trans->iters_live |= 1 << idx;
if (trans->iters_linked &&
!(trans->iters_linked & (1 << idx)))
bch2_btree_iter_link(&trans->iters[__ffs(trans->iters_linked)],
iter);
trans->iters_linked |= 1 << idx;
btree_trans_verify(trans);
BUG_ON(iter->btree_id != btree_id);
BUG_ON((iter->flags ^ flags) & BTREE_ITER_TYPE);
return iter;
}
struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
enum btree_id btree_id,
struct bpos pos, unsigned flags,
u64 iter_id)
{
struct btree_iter *iter =
__btree_trans_get_iter(trans, btree_id, flags, iter_id);
if (!IS_ERR(iter))
bch2_btree_iter_set_pos(iter, pos);
return iter;
}
struct btree_iter *__bch2_trans_copy_iter(struct btree_trans *trans,
struct btree_iter *src,
u64 iter_id)
{
struct btree_iter *iter =
__btree_trans_get_iter(trans, src->btree_id,
src->flags, iter_id);
if (!IS_ERR(iter))
bch2_btree_iter_copy(iter, src);
return iter;
}
void *bch2_trans_kmalloc(struct btree_trans *trans,
size_t size)
{
void *ret;
if (trans->mem_top + size > trans->mem_bytes) {
size_t old_bytes = trans->mem_bytes;
size_t new_bytes = roundup_pow_of_two(trans->mem_top + size);
void *new_mem = krealloc(trans->mem, new_bytes, GFP_NOFS);
if (!new_mem)
return ERR_PTR(-ENOMEM);
trans->mem = new_mem;
trans->mem_bytes = new_bytes;
if (old_bytes) {
trans_restart();
return ERR_PTR(-EINTR);
}
}
ret = trans->mem + trans->mem_top;
trans->mem_top += size;
return ret;
}
int bch2_trans_unlock(struct btree_trans *trans)
{
unsigned iters = trans->iters_linked;
int ret = 0;
while (iters) {
unsigned idx = __ffs(iters);
struct btree_iter *iter = &trans->iters[idx];
if (iter->flags & BTREE_ITER_ERROR)
ret = -EIO;
__bch2_btree_iter_unlock(iter);
iters ^= 1 << idx;
}
return ret;
}
void __bch2_trans_begin(struct btree_trans *trans)
{
unsigned idx;
btree_trans_verify(trans);
/*
* On transaction restart, the transaction isn't required to allocate
* all the same iterators it on the last iteration:
*
* Unlink any iterators it didn't use this iteration, assuming it got
* further (allocated an iter with a higher idx) than where the iter
* was originally allocated:
*/
while (trans->iters_linked &&
trans->iters_live &&
(idx = __fls(trans->iters_linked)) >
__fls(trans->iters_live)) {
trans->iters_linked ^= 1 << idx;
bch2_btree_iter_unlink(&trans->iters[idx]);
}
trans->iters_live = 0;
trans->nr_updates = 0;
trans->mem_top = 0;
btree_trans_verify(trans);
}
void bch2_trans_init(struct btree_trans *trans, struct bch_fs *c)
{
trans->c = c;
trans->nr_restarts = 0;
trans->nr_iters = 0;
trans->iters_live = 0;
trans->iters_linked = 0;
trans->nr_updates = 0;
trans->mem_top = 0;
trans->mem_bytes = 0;
trans->mem = NULL;
trans->iters = trans->iters_onstack;
}
int bch2_trans_exit(struct btree_trans *trans)
{
int ret = bch2_trans_unlock(trans);
kfree(trans->mem);
if (trans->iters != trans->iters_onstack)
mempool_free(trans->iters, &trans->c->btree_iters_pool);
trans->mem = (void *) 0x1;
trans->iters = (void *) 0x1;
return ret;
}
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