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5e6a668b19
linux/fs/bcachefs/btree_iter.c
Kent Overstreet 5e6a668b19 bcachefs: Fix transaction restarts due to upgrading of cloned iterators 
This fixes a regression from
  52d86202fd bcachefs: Improve bch2_btree_iter_traverse_all()

We want to avoid mucking with other iterators in the btree transaction
in operations that are only supposed to be touching individual iterators
- that patch was a cleanup to move lock ordering handling to
bch2_btree_iter_traverse_all(). But it broke upgrading of cloned
iterators.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:00 -04:00

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// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "bkey_methods.h"
#include "bkey_buf.h"
#include "btree_cache.h"
#include "btree_iter.h"
#include "btree_key_cache.h"
#include "btree_locking.h"
#include "btree_update.h"
#include "debug.h"
#include "error.h"
#include "extents.h"
#include "journal.h"
#include "replicas.h"
#include "trace.h"
#include <linux/prefetch.h>
static void btree_iter_set_search_pos(struct btree_iter *, struct bpos);
static inline struct bpos bkey_successor(struct btree_iter *iter, struct bpos p)
{
EBUG_ON(btree_iter_type(iter) == BTREE_ITER_NODES);
/* Are we iterating over keys in all snapshots? */
if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
p = bpos_successor(p);
} else {
p = bpos_nosnap_successor(p);
p.snapshot = iter->snapshot;
}
return p;
}
static inline struct bpos bkey_predecessor(struct btree_iter *iter, struct bpos p)
{
EBUG_ON(btree_iter_type(iter) == BTREE_ITER_NODES);
/* Are we iterating over keys in all snapshots? */
if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
p = bpos_predecessor(p);
} else {
p = bpos_nosnap_predecessor(p);
p.snapshot = iter->snapshot;
}
return p;
}
static inline bool is_btree_node(struct btree_iter *iter, unsigned l)
{
return l < BTREE_MAX_DEPTH &&
(unsigned long) iter->l[l].b >= 128;
}
static inline struct bpos btree_iter_search_key(struct btree_iter *iter)
{
struct bpos pos = iter->pos;
if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
bkey_cmp(pos, POS_MAX))
pos = bkey_successor(iter, pos);
return pos;
}
static inline bool btree_iter_pos_before_node(struct btree_iter *iter,
struct btree *b)
{
return bpos_cmp(iter->real_pos, b->data->min_key) < 0;
}
static inline bool btree_iter_pos_after_node(struct btree_iter *iter,
struct btree *b)
{
return bpos_cmp(b->key.k.p, iter->real_pos) < 0;
}
static inline bool btree_iter_pos_in_node(struct btree_iter *iter,
struct btree *b)
{
return iter->btree_id == b->c.btree_id &&
!btree_iter_pos_before_node(iter, b) &&
!btree_iter_pos_after_node(iter, b);
}
/* Btree node locking: */
void bch2_btree_node_unlock_write(struct btree *b, struct btree_iter *iter)
{
bch2_btree_node_unlock_write_inlined(b, iter);
}
void __bch2_btree_node_lock_write(struct btree *b, struct btree_iter *iter)
{
struct btree_iter *linked;
unsigned readers = 0;
EBUG_ON(!btree_node_intent_locked(iter, b->c.level));
trans_for_each_iter(iter->trans, linked)
if (linked->l[b->c.level].b == b &&
btree_node_read_locked(linked, b->c.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:
*/
if (!b->c.lock.readers)
atomic64_sub(__SIX_VAL(read_lock, readers),
&b->c.lock.state.counter);
else
this_cpu_sub(*b->c.lock.readers, readers);
btree_node_lock_type(iter->trans->c, b, SIX_LOCK_write);
if (!b->c.lock.readers)
atomic64_add(__SIX_VAL(read_lock, readers),
&b->c.lock.state.counter);
else
this_cpu_add(*b->c.lock.readers, readers);
}
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 (!is_btree_node(iter, level))
return false;
if (race_fault())
return false;
if (six_relock_type(&b->c.lock, want, iter->l[level].lock_seq) ||
(btree_node_lock_seq_matches(iter, b, level) &&
btree_node_lock_increment(iter->trans, b, level, want))) {
mark_btree_node_locked(iter, level, want);
return true;
} else {
return false;
}
}
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->c.lock)
: six_relock_type(&b->c.lock, SIX_LOCK_intent, iter->l[level].lock_seq))
goto success;
if (btree_node_lock_seq_matches(iter, b, level) &&
btree_node_lock_increment(iter->trans, 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, bool trace)
{
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))) {
if (trace)
(upgrade
? trace_node_upgrade_fail
: trace_node_relock_fail)(l, iter->l[l].lock_seq,
is_btree_node(iter, l)
? 0
: (unsigned long) iter->l[l].b,
is_btree_node(iter, l)
? iter->l[l].b->c.lock.state.seq
: 0);
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_NO_NODE_GET_LOCKS;
--fail_idx;
}
if (iter->uptodate == BTREE_ITER_NEED_RELOCK)
iter->uptodate = BTREE_ITER_NEED_PEEK;
bch2_btree_trans_verify_locks(iter->trans);
return iter->uptodate < BTREE_ITER_NEED_RELOCK;
}
static struct bpos btree_node_pos(struct btree_bkey_cached_common *_b,
enum btree_iter_type type)
{
return type != BTREE_ITER_CACHED
? container_of(_b, struct btree, c)->key.k.p
: container_of(_b, struct bkey_cached, c)->key.pos;
}
/* Slowpath: */
bool __bch2_btree_node_lock(struct btree *b, struct bpos pos,
unsigned level, struct btree_iter *iter,
enum six_lock_type type,
six_lock_should_sleep_fn should_sleep_fn, void *p,
unsigned long ip)
{
struct btree_trans *trans = iter->trans;
struct btree_iter *linked, *deadlock_iter = NULL;
u64 start_time = local_clock();
unsigned reason = 9;
bool ret;
/* Check if it's safe to block: */
trans_for_each_iter(trans, linked) {
if (!linked->nodes_locked)
continue;
/*
* 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) {
deadlock_iter = linked;
reason = 1;
}
if (linked->btree_id != iter->btree_id) {
if (linked->btree_id > iter->btree_id) {
deadlock_iter = linked;
reason = 3;
}
continue;
}
/*
* Within the same btree, cached iterators come before non
* cached iterators:
*/
if (btree_iter_is_cached(linked) != btree_iter_is_cached(iter)) {
if (btree_iter_is_cached(iter)) {
deadlock_iter = linked;
reason = 4;
}
continue;
}
/*
* 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 (level > __fls(linked->nodes_locked)) {
deadlock_iter = linked;
reason = 5;
}
/* Must lock btree nodes in key order: */
if (btree_node_locked(linked, level) &&
bpos_cmp(pos, btree_node_pos((void *) linked->l[level].b,
btree_iter_type(linked))) <= 0) {
deadlock_iter = linked;
reason = 7;
}
}
if (unlikely(deadlock_iter)) {
trace_trans_restart_would_deadlock(iter->trans->ip, ip,
trans->in_traverse_all, reason,
deadlock_iter->btree_id,
btree_iter_type(deadlock_iter),
&deadlock_iter->real_pos,
iter->btree_id,
btree_iter_type(iter),
&pos);
return false;
}
if (six_trylock_type(&b->c.lock, type))
return true;
#ifdef CONFIG_BCACHEFS_DEBUG
trans->locking_iter_idx = iter->idx;
trans->locking_pos = pos;
trans->locking_btree_id = iter->btree_id;
trans->locking_level = level;
trans->locking = b;
#endif
ret = six_lock_type(&b->c.lock, type, should_sleep_fn, p) == 0;
#ifdef CONFIG_BCACHEFS_DEBUG
trans->locking = NULL;
#endif
if (ret)
bch2_time_stats_update(&trans->c->times[lock_to_time_stat(type)],
start_time);
return ret;
}
/* Btree iterator locking: */
#ifdef CONFIG_BCACHEFS_DEBUG
static void bch2_btree_iter_verify_locks(struct btree_iter *iter)
{
unsigned l;
if (!(iter->trans->iters_linked & (1ULL << iter->idx))) {
BUG_ON(iter->nodes_locked);
return;
}
for (l = 0; is_btree_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));
}
}
void bch2_btree_trans_verify_locks(struct btree_trans *trans)
{
struct btree_iter *iter;
trans_for_each_iter(trans, iter)
bch2_btree_iter_verify_locks(iter);
}
#else
static inline void bch2_btree_iter_verify_locks(struct btree_iter *iter) {}
#endif
__flatten
bool bch2_btree_iter_relock(struct btree_iter *iter, bool trace)
{
return btree_iter_get_locks(iter, false, trace);
}
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, true))
return true;
/*
* XXX: this is ugly - we'd prefer to not be mucking with other
* iterators in the btree_trans here.
*
* On failure to upgrade the iterator, setting iter->locks_want and
* calling get_locks() is sufficient to make bch2_btree_iter_traverse()
* get the locks we want on transaction restart.
*
* But if this iterator was a clone, on transaction restart what we did
* to this iterator isn't going to be preserved.
*
* Possibly we could add an iterator field for the parent iterator when
* an iterator is a copy - for now, we'll just upgrade any other
* iterators with the same btree id.
*
* The code below used to be needed to ensure ancestor nodes get locked
* before interior nodes - now that's handled by
* bch2_btree_iter_traverse_all().
*/
trans_for_each_iter(iter->trans, linked)
if (linked != iter &&
btree_iter_type(linked) == btree_iter_type(iter) &&
linked->btree_id == iter->btree_id &&
linked->locks_want < new_locks_want) {
linked->locks_want = new_locks_want;
btree_iter_get_locks(linked, true, false);
}
return false;
}
void __bch2_btree_iter_downgrade(struct btree_iter *iter,
unsigned new_locks_want)
{
unsigned l;
EBUG_ON(iter->locks_want < new_locks_want);
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;
}
}
bch2_btree_trans_verify_locks(iter->trans);
}
void bch2_trans_downgrade(struct btree_trans *trans)
{
struct btree_iter *iter;
trans_for_each_iter(trans, iter)
bch2_btree_iter_downgrade(iter);
}
/* Btree transaction locking: */
bool bch2_trans_relock(struct btree_trans *trans)
{
struct btree_iter *iter;
trans_for_each_iter(trans, iter)
if (!bch2_btree_iter_relock(iter, true)) {
trace_trans_restart_relock(trans->ip);
return false;
}
return true;
}
void bch2_trans_unlock(struct btree_trans *trans)
{
struct btree_iter *iter;
trans_for_each_iter(trans, iter)
__bch2_btree_iter_unlock(iter);
}
/* Btree iterator: */
#ifdef CONFIG_BCACHEFS_DEBUG
static void bch2_btree_iter_verify_cached(struct btree_iter *iter)
{
struct bkey_cached *ck;
bool locked = btree_node_locked(iter, 0);
if (!bch2_btree_node_relock(iter, 0))
return;
ck = (void *) iter->l[0].b;
BUG_ON(ck->key.btree_id != iter->btree_id ||
bkey_cmp(ck->key.pos, iter->pos));
if (!locked)
btree_node_unlock(iter, 0);
}
static void bch2_btree_iter_verify_level(struct btree_iter *iter,
unsigned level)
{
struct btree_iter_level *l;
struct btree_node_iter tmp;
bool locked;
struct bkey_packed *p, *k;
char buf1[100], buf2[100], buf3[100];
const char *msg;
if (!bch2_debug_check_iterators)
return;
l = &iter->l[level];
tmp = l->iter;
locked = btree_node_locked(iter, level);
if (btree_iter_type(iter) == BTREE_ITER_CACHED) {
if (!level)
bch2_btree_iter_verify_cached(iter);
return;
}
BUG_ON(iter->level < iter->min_depth);
if (!btree_iter_node(iter, level))
return;
if (!bch2_btree_node_relock(iter, level))
return;
BUG_ON(!btree_iter_pos_in_node(iter, l->b));
/*
* node iterators don't use leaf node iterator:
*/
if (btree_iter_type(iter) == BTREE_ITER_NODES &&
level <= iter->min_depth)
goto unlock;
bch2_btree_node_iter_verify(&l->iter, l->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)
*/
p = level || btree_node_type_is_extents(iter->btree_id)
? bch2_btree_node_iter_prev(&tmp, l->b)
: bch2_btree_node_iter_prev_all(&tmp, l->b);
k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
if (p && bkey_iter_pos_cmp(l->b, p, &iter->real_pos) >= 0) {
msg = "before";
goto err;
}
if (k && bkey_iter_pos_cmp(l->b, k, &iter->real_pos) < 0) {
msg = "after";
goto err;
}
unlock:
if (!locked)
btree_node_unlock(iter, level);
return;
err:
strcpy(buf2, "(none)");
strcpy(buf3, "(none)");
bch2_bpos_to_text(&PBUF(buf1), iter->real_pos);
if (p) {
struct bkey uk = bkey_unpack_key(l->b, p);
bch2_bkey_to_text(&PBUF(buf2), &uk);
}
if (k) {
struct bkey uk = bkey_unpack_key(l->b, k);
bch2_bkey_to_text(&PBUF(buf3), &uk);
}
panic("iterator should be %s key at level %u:\n"
"iter pos %s\n"
"prev key %s\n"
"cur key %s\n",
msg, level, buf1, buf2, buf3);
}
static void bch2_btree_iter_verify(struct btree_iter *iter)
{
enum btree_iter_type type = btree_iter_type(iter);
unsigned i;
EBUG_ON(iter->btree_id >= BTREE_ID_NR);
BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
iter->pos.snapshot != iter->snapshot);
BUG_ON((iter->flags & BTREE_ITER_IS_EXTENTS) &&
(iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
BUG_ON(type == BTREE_ITER_NODES &&
!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
BUG_ON(type != BTREE_ITER_NODES &&
(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
!btree_type_has_snapshots(iter->btree_id));
bch2_btree_iter_verify_locks(iter);
for (i = 0; i < BTREE_MAX_DEPTH; i++)
bch2_btree_iter_verify_level(iter, i);
}
static void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter)
{
enum btree_iter_type type = btree_iter_type(iter);
BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
iter->pos.snapshot != iter->snapshot);
BUG_ON((type == BTREE_ITER_KEYS ||
type == BTREE_ITER_CACHED) &&
(bkey_cmp(iter->pos, bkey_start_pos(&iter->k)) < 0 ||
bkey_cmp(iter->pos, iter->k.p) > 0));
}
void bch2_btree_trans_verify_iters(struct btree_trans *trans, struct btree *b)
{
struct btree_iter *iter;
if (!bch2_debug_check_iterators)
return;
trans_for_each_iter_with_node(trans, b, iter)
bch2_btree_iter_verify_level(iter, b->c.level);
}
#else
static inline void bch2_btree_iter_verify_level(struct btree_iter *iter, unsigned l) {}
static inline void bch2_btree_iter_verify(struct btree_iter *iter) {}
static inline void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter) {}
#endif
static void btree_node_iter_set_set_pos(struct btree_node_iter *iter,
struct btree *b,
struct bset_tree *t,
struct bkey_packed *k)
{
struct btree_node_iter_set *set;
btree_node_iter_for_each(iter, set)
if (set->end == t->end_offset) {
set->k = __btree_node_key_to_offset(b, k);
bch2_btree_node_iter_sort(iter, b);
return;
}
bch2_btree_node_iter_push(iter, b, k, btree_bkey_last(b, t));
}
static void __bch2_btree_iter_fix_key_modified(struct btree_iter *iter,
struct btree *b,
struct bkey_packed *where)
{
struct btree_iter_level *l = &iter->l[b->c.level];
if (where != bch2_btree_node_iter_peek_all(&l->iter, l->b))
return;
if (bkey_iter_pos_cmp(l->b, where, &iter->real_pos) < 0)
bch2_btree_node_iter_advance(&l->iter, l->b);
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
}
void bch2_btree_iter_fix_key_modified(struct btree_iter *iter,
struct btree *b,
struct bkey_packed *where)
{
struct btree_iter *linked;
trans_for_each_iter_with_node(iter->trans, b, linked) {
__bch2_btree_iter_fix_key_modified(linked, b, where);
bch2_btree_iter_verify_level(linked, b->c.level);
}
}
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;
unsigned orig_iter_pos = node_iter->data[0].k;
bool iter_current_key_modified =
orig_iter_pos >= offset &&
orig_iter_pos <= offset + clobber_u64s;
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 &&
bkey_iter_pos_cmp(b, where, &iter->real_pos) >= 0) {
bch2_btree_node_iter_push(node_iter, b, where, end);
goto fixup_done;
} else {
/* Iterator is after key that changed */
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 &&
bkey_iter_pos_cmp(b, where, &iter->real_pos) >= 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 {
/* Iterator is after key that changed */
set->k = (int) set->k + shift;
return;
}
bch2_btree_node_iter_sort(node_iter, b);
fixup_done:
if (node_iter->data[0].k != orig_iter_pos)
iter_current_key_modified = true;
/*
* When a new key is added, and the node iterator now points to that
* key, the iterator might have skipped past deleted keys that should
* come after the key the iterator now points to. We have to rewind to
* before those deleted keys - otherwise
* bch2_btree_node_iter_prev_all() breaks:
*/
if (!bch2_btree_node_iter_end(node_iter) &&
iter_current_key_modified &&
(b->c.level ||
btree_node_type_is_extents(iter->btree_id))) {
struct bset_tree *t;
struct bkey_packed *k, *k2, *p;
k = bch2_btree_node_iter_peek_all(node_iter, b);
for_each_bset(b, t) {
bool set_pos = false;
if (node_iter->data[0].end == t->end_offset)
continue;
k2 = bch2_btree_node_iter_bset_pos(node_iter, b, t);
while ((p = bch2_bkey_prev_all(b, t, k2)) &&
bkey_iter_cmp(b, k, p) < 0) {
k2 = p;
set_pos = true;
}
if (set_pos)
btree_node_iter_set_set_pos(node_iter,
b, t, k2);
}
}
if (!b->c.level &&
node_iter == &iter->l[0].iter &&
iter_current_key_modified)
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
}
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->c.level].iter) {
__bch2_btree_node_iter_fix(iter, b, node_iter, t,
where, clobber_u64s, new_u64s);
if (bch2_debug_check_iterators)
bch2_btree_node_iter_verify(node_iter, b);
}
trans_for_each_iter_with_node(iter->trans, b, linked) {
__bch2_btree_node_iter_fix(linked, b,
&linked->l[b->c.level].iter, t,
where, clobber_u64s, new_u64s);
bch2_btree_iter_verify_level(linked, b->c.level);
}
}
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 (bch2_debug_check_bkeys)
bch2_bkey_debugcheck(iter->trans->c, l->b, ret);
return ret;
}
/* peek_all() doesn't skip deleted keys */
static inline struct bkey_s_c btree_iter_level_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_level_peek(struct btree_iter *iter,
struct btree_iter_level *l)
{
struct bkey_s_c k = __btree_iter_unpack(iter, l, &iter->k,
bch2_btree_node_iter_peek(&l->iter, l->b));
iter->real_pos = k.k ? k.k->p : l->b->key.k.p;
return k;
}
static inline struct bkey_s_c btree_iter_level_prev(struct btree_iter *iter,
struct btree_iter_level *l)
{
struct bkey_s_c k = __btree_iter_unpack(iter, l, &iter->k,
bch2_btree_node_iter_prev(&l->iter, l->b));
iter->real_pos = k.k ? k.k->p : l->b->data->min_key;
return k;
}
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)) &&
bkey_iter_pos_cmp(l->b, k, &iter->real_pos) < 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->c.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 buf1[100];
char buf2[100];
char buf3[100];
char buf4[100];
struct bkey uk = bkey_unpack_key(b, k);
bch2_dump_btree_node(iter->trans->c, l->b);
bch2_bpos_to_text(&PBUF(buf1), iter->real_pos);
bch2_bkey_to_text(&PBUF(buf2), &uk);
bch2_bpos_to_text(&PBUF(buf3), b->data->min_key);
bch2_bpos_to_text(&PBUF(buf3), b->data->max_key);
panic("parent iter doesn't point to new node:\n"
"iter pos %s %s\n"
"iter key %s\n"
"new node %s-%s\n",
bch2_btree_ids[iter->btree_id], buf1,
buf2, buf3, buf4);
}
if (!parent_locked)
btree_node_unlock(iter, b->c.level + 1);
}
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->real_pos);
/*
* Iterators to interior nodes should always be pointed at the 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)
{
BUG_ON(btree_iter_type(iter) == BTREE_ITER_CACHED);
btree_iter_verify_new_node(iter, b);
EBUG_ON(!btree_iter_pos_in_node(iter, b));
EBUG_ON(b->c.lock.state.seq & 1);
iter->l[b->c.level].lock_seq = b->c.lock.state.seq;
iter->l[b->c.level].b = b;
__btree_iter_init(iter, b->c.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;
trans_for_each_iter(iter->trans, linked)
if (btree_iter_type(linked) != BTREE_ITER_CACHED &&
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->c.level));
t = btree_lock_want(linked, b->c.level);
if (t != BTREE_NODE_UNLOCKED) {
six_lock_increment(&b->c.lock, (enum six_lock_type) t);
mark_btree_node_locked(linked, b->c.level, (enum six_lock_type) t);
}
btree_iter_node_set(linked, b);
}
}
void bch2_btree_iter_node_drop(struct btree_iter *iter, struct btree *b)
{
struct btree_iter *linked;
unsigned level = b->c.level;
trans_for_each_iter(iter->trans, linked)
if (linked->l[level].b == b) {
btree_node_unlock(linked, level);
linked->l[level].b = BTREE_ITER_NO_NODE_DROP;
}
}
/*
* 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;
trans_for_each_iter_with_node(iter->trans, b, linked)
__btree_iter_init(linked, b->c.level);
}
static int lock_root_check_fn(struct six_lock *lock, void *p)
{
struct btree *b = container_of(lock, struct btree, c.lock);
struct btree **rootp = p;
return b == *rootp ? 0 : -1;
}
static inline int btree_iter_lock_root(struct btree_iter *iter,
unsigned depth_want,
unsigned long trace_ip)
{
struct bch_fs *c = iter->trans->c;
struct btree *b, **rootp = &c->btree_roots[iter->btree_id].b;
enum six_lock_type lock_type;
unsigned i;
EBUG_ON(iter->nodes_locked);
while (1) {
b = READ_ONCE(*rootp);
iter->level = READ_ONCE(b->c.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;
for (i = iter->level; i < BTREE_MAX_DEPTH; i++)
iter->l[i].b = NULL;
return 1;
}
lock_type = __btree_lock_want(iter, iter->level);
if (unlikely(!btree_node_lock(b, POS_MAX, iter->level,
iter, lock_type,
lock_root_check_fn, rootp,
trace_ip)))
return -EINTR;
if (likely(b == READ_ONCE(*rootp) &&
b->c.level == iter->level &&
!race_fault())) {
for (i = 0; i < iter->level; i++)
iter->l[i].b = BTREE_ITER_NO_NODE_LOCK_ROOT;
iter->l[iter->level].b = b;
for (i = iter->level + 1; i < BTREE_MAX_DEPTH; i++)
iter->l[i].b = NULL;
mark_btree_node_locked(iter, iter->level, lock_type);
btree_iter_node_set(iter, b);
return 0;
}
six_unlock_type(&b->c.lock, lock_type);
}
}
noinline
static void btree_iter_prefetch(struct btree_iter *iter)
{
struct bch_fs *c = iter->trans->c;
struct btree_iter_level *l = &iter->l[iter->level];
struct btree_node_iter node_iter = l->iter;
struct bkey_packed *k;
struct bkey_buf tmp;
unsigned nr = test_bit(BCH_FS_STARTED, &c->flags)
? (iter->level > 1 ? 0 : 2)
: (iter->level > 1 ? 1 : 16);
bool was_locked = btree_node_locked(iter, iter->level);
bch2_bkey_buf_init(&tmp);
while (nr) {
if (!bch2_btree_node_relock(iter, iter->level))
break;
bch2_btree_node_iter_advance(&node_iter, l->b);
k = bch2_btree_node_iter_peek(&node_iter, l->b);
if (!k)
break;
bch2_bkey_buf_unpack(&tmp, c, l->b, k);
bch2_btree_node_prefetch(c, iter, tmp.k, iter->btree_id,
iter->level - 1);
}
if (!was_locked)
btree_node_unlock(iter, iter->level);
bch2_bkey_buf_exit(&tmp, c);
}
static noinline void btree_node_mem_ptr_set(struct btree_iter *iter,
unsigned plevel, struct btree *b)
{
struct btree_iter_level *l = &iter->l[plevel];
bool locked = btree_node_locked(iter, plevel);
struct bkey_packed *k;
struct bch_btree_ptr_v2 *bp;
if (!bch2_btree_node_relock(iter, plevel))
return;
k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
BUG_ON(k->type != KEY_TYPE_btree_ptr_v2);
bp = (void *) bkeyp_val(&l->b->format, k);
bp->mem_ptr = (unsigned long)b;
if (!locked)
btree_node_unlock(iter, plevel);
}
static __always_inline int btree_iter_down(struct btree_iter *iter,
unsigned long trace_ip)
{
struct bch_fs *c = iter->trans->c;
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);
struct bkey_buf tmp;
int ret;
EBUG_ON(!btree_node_locked(iter, iter->level));
bch2_bkey_buf_init(&tmp);
bch2_bkey_buf_unpack(&tmp, c, l->b,
bch2_btree_node_iter_peek(&l->iter, l->b));
b = bch2_btree_node_get(c, iter, tmp.k, level, lock_type, trace_ip);
ret = PTR_ERR_OR_ZERO(b);
if (unlikely(ret))
goto err;
mark_btree_node_locked(iter, level, lock_type);
btree_iter_node_set(iter, b);
if (tmp.k->k.type == KEY_TYPE_btree_ptr_v2 &&
unlikely(b != btree_node_mem_ptr(tmp.k)))
btree_node_mem_ptr_set(iter, level + 1, b);
if (iter->flags & BTREE_ITER_PREFETCH)
btree_iter_prefetch(iter);
iter->level = level;
err:
bch2_bkey_buf_exit(&tmp, c);
return ret;
}
static int btree_iter_traverse_one(struct btree_iter *, unsigned long);
static int __btree_iter_traverse_all(struct btree_trans *trans, int ret)
{
struct bch_fs *c = trans->c;
struct btree_iter *iter;
u8 sorted[BTREE_ITER_MAX];
int i, nr_sorted = 0;
bool relock_fail;
if (trans->in_traverse_all)
return -EINTR;
trans->in_traverse_all = true;
retry_all:
nr_sorted = 0;
relock_fail = false;
trans_for_each_iter(trans, iter) {
if (!bch2_btree_iter_relock(iter, true))
relock_fail = true;
sorted[nr_sorted++] = iter->idx;
}
if (!relock_fail) {
trans->in_traverse_all = false;
return 0;
}
#define btree_iter_cmp_by_idx(_l, _r) \
btree_iter_lock_cmp(&trans->iters[_l], &trans->iters[_r])
bubble_sort(sorted, nr_sorted, btree_iter_cmp_by_idx);
#undef btree_iter_cmp_by_idx
for (i = nr_sorted - 2; i >= 0; --i) {
struct btree_iter *iter1 = trans->iters + sorted[i];
struct btree_iter *iter2 = trans->iters + sorted[i + 1];
if (iter1->btree_id == iter2->btree_id &&
iter1->locks_want < iter2->locks_want)
__bch2_btree_iter_upgrade(iter1, iter2->locks_want);
else if (!iter1->locks_want && iter2->locks_want)
__bch2_btree_iter_upgrade(iter1, 1);
}
bch2_trans_unlock(trans);
cond_resched();
if (unlikely(ret == -ENOMEM)) {
struct closure cl;
closure_init_stack(&cl);
do {
ret = bch2_btree_cache_cannibalize_lock(c, &cl);
closure_sync(&cl);
} while (ret);
}
if (unlikely(ret == -EIO)) {
trans->error = true;
goto out;
}
BUG_ON(ret && ret != -EINTR);
/* Now, redo traversals in correct order: */
for (i = 0; i < nr_sorted; i++) {
unsigned idx = sorted[i];
/*
* sucessfully traversing one iterator can cause another to be
* unlinked, in btree_key_cache_fill()
*/
if (!(trans->iters_linked & (1ULL << idx)))
continue;
ret = btree_iter_traverse_one(&trans->iters[idx], _THIS_IP_);
if (ret)
goto retry_all;
}
if (hweight64(trans->iters_live) > 1)
ret = -EINTR;
else
trans_for_each_iter(trans, iter)
if (iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT) {
ret = -EINTR;
break;
}
out:
bch2_btree_cache_cannibalize_unlock(c);
trans->in_traverse_all = false;
trace_trans_traverse_all(trans->ip);
return ret;
}
int bch2_btree_iter_traverse_all(struct btree_trans *trans)
{
return __btree_iter_traverse_all(trans, 0);
}
static inline bool btree_iter_good_node(struct btree_iter *iter,
unsigned l, int check_pos)
{
if (!is_btree_node(iter, l) ||
!bch2_btree_node_relock(iter, l))
return false;
if (check_pos < 0 && btree_iter_pos_before_node(iter, iter->l[l].b))
return false;
if (check_pos > 0 && btree_iter_pos_after_node(iter, iter->l[l].b))
return false;
return true;
}
static inline unsigned btree_iter_up_until_good_node(struct btree_iter *iter,
int check_pos)
{
unsigned l = iter->level;
while (btree_iter_node(iter, l) &&
!btree_iter_good_node(iter, l, check_pos)) {
btree_node_unlock(iter, l);
iter->l[l].b = BTREE_ITER_NO_NODE_UP;
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_trans_exit().
*/
static int btree_iter_traverse_one(struct btree_iter *iter,
unsigned long trace_ip)
{
unsigned depth_want = iter->level;
/*
* if we need interior nodes locked, call btree_iter_relock() to make
* sure we walk back up enough that we lock them:
*/
if (iter->uptodate == BTREE_ITER_NEED_RELOCK ||
iter->locks_want > 1)
bch2_btree_iter_relock(iter, false);
if (btree_iter_type(iter) == BTREE_ITER_CACHED)
return bch2_btree_iter_traverse_cached(iter);
if (iter->uptodate < BTREE_ITER_NEED_RELOCK)
return 0;
if (unlikely(iter->level >= BTREE_MAX_DEPTH))
return 0;
iter->level = btree_iter_up_until_good_node(iter, 0);
/*
* 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, trace_ip)
: btree_iter_lock_root(iter, depth_want, trace_ip);
if (unlikely(ret)) {
if (ret == 1)
return 0;
iter->level = depth_want;
if (ret == -EIO) {
iter->flags |= BTREE_ITER_ERROR;
iter->l[iter->level].b =
BTREE_ITER_NO_NODE_ERROR;
} else {
iter->l[iter->level].b =
BTREE_ITER_NO_NODE_DOWN;
}
return ret;
}
}
iter->uptodate = BTREE_ITER_NEED_PEEK;
bch2_btree_iter_verify(iter);
return 0;
}
static int __must_check __bch2_btree_iter_traverse(struct btree_iter *iter)
{
struct btree_trans *trans = iter->trans;
int ret;
ret = bch2_trans_cond_resched(trans) ?:
btree_iter_traverse_one(iter, _RET_IP_);
if (unlikely(ret))
ret = __btree_iter_traverse_all(trans, ret);
return ret;
}
/*
* Note:
* bch2_btree_iter_traverse() is for external users, btree_iter_traverse() is
* for internal btree iterator users
*
* bch2_btree_iter_traverse sets iter->real_pos to iter->pos,
* btree_iter_traverse() does not:
*/
static inline int __must_check
btree_iter_traverse(struct btree_iter *iter)
{
return iter->uptodate >= BTREE_ITER_NEED_RELOCK
? __bch2_btree_iter_traverse(iter)
: 0;
}
int __must_check
bch2_btree_iter_traverse(struct btree_iter *iter)
{
btree_iter_set_search_pos(iter, btree_iter_search_key(iter));
return btree_iter_traverse(iter);
}
/* Iterate across nodes (leaf and interior nodes) */
struct btree *bch2_btree_iter_peek_node(struct btree_iter *iter)
{
struct btree *b;
int ret;
EBUG_ON(btree_iter_type(iter) != BTREE_ITER_NODES);
bch2_btree_iter_verify(iter);
ret = btree_iter_traverse(iter);
if (ret)
return NULL;
b = btree_iter_node(iter, iter->level);
if (!b)
return NULL;
BUG_ON(bpos_cmp(b->key.k.p, iter->pos) < 0);
iter->pos = iter->real_pos = b->key.k.p;
bch2_btree_iter_verify(iter);
return b;
}
struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
{
struct btree *b;
int ret;
EBUG_ON(btree_iter_type(iter) != BTREE_ITER_NODES);
bch2_btree_iter_verify(iter);
/* already got to end? */
if (!btree_iter_node(iter, iter->level))
return NULL;
bch2_trans_cond_resched(iter->trans);
btree_node_unlock(iter, iter->level);
iter->l[iter->level].b = BTREE_ITER_NO_NODE_UP;
iter->level++;
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
ret = btree_iter_traverse(iter);
if (ret)
return NULL;
/* got to end? */
b = btree_iter_node(iter, iter->level);
if (!b)
return NULL;
if (bpos_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
*/
btree_iter_set_search_pos(iter, bpos_successor(iter->pos));
/* Unlock to avoid screwing up our lock invariants: */
btree_node_unlock(iter, iter->level);
iter->level = iter->min_depth;
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
bch2_btree_iter_verify(iter);
ret = btree_iter_traverse(iter);
if (ret)
return NULL;
b = iter->l[iter->level].b;
}
iter->pos = iter->real_pos = b->key.k.p;
bch2_btree_iter_verify(iter);
return b;
}
/* Iterate across keys (in leaf nodes only) */
static void btree_iter_set_search_pos(struct btree_iter *iter, struct bpos new_pos)
{
int cmp = bpos_cmp(new_pos, iter->real_pos);
unsigned l = iter->level;
if (!cmp)
goto out;
iter->real_pos = new_pos;
if (unlikely(btree_iter_type(iter) == BTREE_ITER_CACHED)) {
btree_node_unlock(iter, 0);
iter->l[0].b = BTREE_ITER_NO_NODE_UP;
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
return;
}
l = btree_iter_up_until_good_node(iter, cmp);
if (btree_iter_node(iter, l)) {
/*
* 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[l], 8))
__btree_iter_init(iter, l);
/* Don't leave it locked if we're not supposed to: */
if (btree_lock_want(iter, l) == BTREE_NODE_UNLOCKED)
btree_node_unlock(iter, l);
}
out:
if (l != iter->level)
btree_iter_set_dirty(iter, BTREE_ITER_NEED_TRAVERSE);
else
btree_iter_set_dirty(iter, BTREE_ITER_NEED_PEEK);
bch2_btree_iter_verify(iter);
}
inline bool bch2_btree_iter_advance(struct btree_iter *iter)
{
struct bpos pos = iter->k.p;
bool ret = bpos_cmp(pos, POS_MAX) != 0;
if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
pos = bkey_successor(iter, pos);
bch2_btree_iter_set_pos(iter, pos);
return ret;
}
inline bool bch2_btree_iter_rewind(struct btree_iter *iter)
{
struct bpos pos = bkey_start_pos(&iter->k);
bool ret = bpos_cmp(pos, POS_MIN) != 0;
if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
pos = bkey_predecessor(iter, pos);
bch2_btree_iter_set_pos(iter, pos);
return ret;
}
static inline bool btree_iter_set_pos_to_next_leaf(struct btree_iter *iter)
{
struct bpos next_pos = iter->l[0].b->key.k.p;
bool ret = bpos_cmp(next_pos, POS_MAX) != 0;
/*
* Typically, we don't want to modify iter->pos here, since that
* indicates where we searched from - unless we got to the end of the
* btree, in that case we want iter->pos to reflect that:
*/
if (ret)
btree_iter_set_search_pos(iter, bpos_successor(next_pos));
else
bch2_btree_iter_set_pos(iter, POS_MAX);
return ret;
}
static inline bool btree_iter_set_pos_to_prev_leaf(struct btree_iter *iter)
{
struct bpos next_pos = iter->l[0].b->data->min_key;
bool ret = bpos_cmp(next_pos, POS_MIN) != 0;
if (ret)
btree_iter_set_search_pos(iter, bpos_predecessor(next_pos));
else
bch2_btree_iter_set_pos(iter, POS_MIN);
return ret;
}
static struct bkey_i *btree_trans_peek_updates(struct btree_trans *trans,
enum btree_id btree_id, struct bpos pos)
{
struct btree_insert_entry *i;
trans_for_each_update2(trans, i)
if ((cmp_int(btree_id, i->iter->btree_id) ?:
bkey_cmp(pos, i->k->k.p)) <= 0) {
if (btree_id == i->iter->btree_id)
return i->k;
break;
}
return NULL;
}
static inline struct bkey_s_c __btree_iter_peek(struct btree_iter *iter, bool with_updates)
{
struct bpos search_key = btree_iter_search_key(iter);
struct bkey_i *next_update = with_updates
? btree_trans_peek_updates(iter->trans, iter->btree_id, search_key)
: NULL;
struct bkey_s_c k;
int ret;
EBUG_ON(btree_iter_type(iter) != BTREE_ITER_KEYS);
bch2_btree_iter_verify(iter);
bch2_btree_iter_verify_entry_exit(iter);
btree_iter_set_search_pos(iter, search_key);
while (1) {
ret = btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
k = btree_iter_level_peek(iter, &iter->l[0]);
if (next_update &&
bpos_cmp(next_update->k.p, iter->real_pos) <= 0)
k = bkey_i_to_s_c(next_update);
if (likely(k.k)) {
if (bkey_deleted(k.k)) {
btree_iter_set_search_pos(iter,
bkey_successor(iter, k.k->p));
continue;
}
break;
}
if (!btree_iter_set_pos_to_next_leaf(iter))
return bkey_s_c_null;
}
/*
* iter->pos should be mononotically increasing, and always be equal to
* the key we just returned - except extents can straddle iter->pos:
*/
if (!(iter->flags & BTREE_ITER_IS_EXTENTS))
iter->pos = k.k->p;
else if (bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0)
iter->pos = bkey_start_pos(k.k);
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
return k;
}
/**
* bch2_btree_iter_peek: returns first key greater than or equal to iterator's
* current position
*/
struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter)
{
return __btree_iter_peek(iter, false);
}
/**
* bch2_btree_iter_next: returns first key greater than iterator's current
* position
*/
struct bkey_s_c bch2_btree_iter_next(struct btree_iter *iter)
{
if (!bch2_btree_iter_advance(iter))
return bkey_s_c_null;
return bch2_btree_iter_peek(iter);
}
struct bkey_s_c bch2_btree_iter_peek_with_updates(struct btree_iter *iter)
{
return __btree_iter_peek(iter, true);
}
struct bkey_s_c bch2_btree_iter_next_with_updates(struct btree_iter *iter)
{
if (!bch2_btree_iter_advance(iter))
return bkey_s_c_null;
return bch2_btree_iter_peek_with_updates(iter);
}
/**
* bch2_btree_iter_peek_prev: returns first key less than or equal to
* iterator's current position
*/
struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct bkey_s_c k;
int ret;
EBUG_ON(btree_iter_type(iter) != BTREE_ITER_KEYS);
bch2_btree_iter_verify(iter);
bch2_btree_iter_verify_entry_exit(iter);
btree_iter_set_search_pos(iter, iter->pos);
while (1) {
ret = btree_iter_traverse(iter);
if (unlikely(ret)) {
k = bkey_s_c_err(ret);
goto no_key;
}
k = btree_iter_level_peek(iter, l);
if (!k.k ||
((iter->flags & BTREE_ITER_IS_EXTENTS)
? bkey_cmp(bkey_start_pos(k.k), iter->pos) >= 0
: bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0))
k = btree_iter_level_prev(iter, l);
if (likely(k.k))
break;
if (!btree_iter_set_pos_to_prev_leaf(iter)) {
k = bkey_s_c_null;
goto no_key;
}
}
EBUG_ON(bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0);
/* Extents can straddle iter->pos: */
if (bkey_cmp(k.k->p, iter->pos) < 0)
iter->pos = k.k->p;
out:
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
return k;
no_key:
/*
* btree_iter_level_peek() may have set iter->k to a key we didn't want, and
* then we errored going to the previous leaf - make sure it's
* consistent with iter->pos:
*/
bkey_init(&iter->k);
iter->k.p = iter->pos;
goto out;
}
/**
* bch2_btree_iter_prev: returns first key less than iterator's current
* position
*/
struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *iter)
{
if (!bch2_btree_iter_rewind(iter))
return bkey_s_c_null;
return bch2_btree_iter_peek_prev(iter);
}
static inline struct bkey_s_c
__bch2_btree_iter_peek_slot_extents(struct btree_iter *iter)
{
struct bkey_s_c k;
struct bpos pos, next_start;
/* keys & 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;
bch2_btree_iter_set_pos(iter, bkey_successor(iter, iter->pos));
}
pos = iter->pos;
k = bch2_btree_iter_peek(iter);
iter->pos = pos;
if (bkey_err(k))
return k;
if (k.k && bkey_cmp(bkey_start_pos(k.k), iter->pos) <= 0)
return k;
next_start = k.k ? bkey_start_pos(k.k) : POS_MAX;
bkey_init(&iter->k);
iter->k.p = iter->pos;
bch2_key_resize(&iter->k,
min_t(u64, KEY_SIZE_MAX,
(next_start.inode == iter->pos.inode
? next_start.offset
: KEY_OFFSET_MAX) -
iter->pos.offset));
EBUG_ON(!iter->k.size);
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
return (struct bkey_s_c) { &iter->k, NULL };
}
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;
EBUG_ON(btree_iter_type(iter) != BTREE_ITER_KEYS);
bch2_btree_iter_verify(iter);
bch2_btree_iter_verify_entry_exit(iter);
btree_iter_set_search_pos(iter, btree_iter_search_key(iter));
if (iter->flags & BTREE_ITER_IS_EXTENTS)
return __bch2_btree_iter_peek_slot_extents(iter);
ret = btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
k = btree_iter_level_peek_all(iter, l, &iter->k);
EBUG_ON(k.k && bkey_deleted(k.k) && bkey_cmp(k.k->p, iter->pos) == 0);
if (!k.k || bkey_cmp(iter->pos, k.k->p)) {
/* hole */
bkey_init(&iter->k);
iter->k.p = iter->pos;
k = (struct bkey_s_c) { &iter->k, NULL };
}
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
return k;
}
struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *iter)
{
if (!bch2_btree_iter_advance(iter))
return bkey_s_c_null;
return bch2_btree_iter_peek_slot(iter);
}
struct bkey_s_c bch2_btree_iter_prev_slot(struct btree_iter *iter)
{
if (!bch2_btree_iter_rewind(iter))
return bkey_s_c_null;
return bch2_btree_iter_peek_slot(iter);
}
struct bkey_s_c bch2_btree_iter_peek_cached(struct btree_iter *iter)
{
struct bkey_cached *ck;
int ret;
EBUG_ON(btree_iter_type(iter) != BTREE_ITER_CACHED);
bch2_btree_iter_verify(iter);
ret = btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
ck = (void *) iter->l[0].b;
EBUG_ON(iter->btree_id != ck->key.btree_id ||
bkey_cmp(iter->pos, ck->key.pos));
BUG_ON(!ck->valid);
return bkey_i_to_s_c(ck->k);
}
static inline void bch2_btree_iter_init(struct btree_trans *trans,
struct btree_iter *iter, enum btree_id btree_id)
{
struct bch_fs *c = trans->c;
unsigned i;
iter->trans = trans;
iter->uptodate = BTREE_ITER_NEED_TRAVERSE;
iter->btree_id = btree_id;
iter->level = 0;
iter->min_depth = 0;
iter->locks_want = 0;
iter->nodes_locked = 0;
iter->nodes_intent_locked = 0;
for (i = 0; i < ARRAY_SIZE(iter->l); i++)
iter->l[i].b = BTREE_ITER_NO_NODE_INIT;
prefetch(c->btree_roots[btree_id].b);
}
/* new transactional stuff: */
static inline void __bch2_trans_iter_free(struct btree_trans *trans,
unsigned idx)
{
__bch2_btree_iter_unlock(&trans->iters[idx]);
trans->iters_linked &= ~(1ULL << idx);
trans->iters_live &= ~(1ULL << idx);
trans->iters_touched &= ~(1ULL << idx);
}
int bch2_trans_iter_put(struct btree_trans *trans,
struct btree_iter *iter)
{
int ret;
if (IS_ERR_OR_NULL(iter))
return 0;
BUG_ON(trans->iters + iter->idx != iter);
BUG_ON(!btree_iter_live(trans, iter));
ret = btree_iter_err(iter);
if (!(trans->iters_touched & (1ULL << iter->idx)) &&
!(iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT))
__bch2_trans_iter_free(trans, iter->idx);
trans->iters_live &= ~(1ULL << iter->idx);
return ret;
}
int bch2_trans_iter_free(struct btree_trans *trans,
struct btree_iter *iter)
{
if (IS_ERR_OR_NULL(iter))
return 0;
set_btree_iter_dontneed(trans, iter);
return bch2_trans_iter_put(trans, iter);
}
noinline __cold
static void btree_trans_iter_alloc_fail(struct btree_trans *trans)
{
struct btree_iter *iter;
struct btree_insert_entry *i;
char buf[100];
trans_for_each_iter(trans, iter)
printk(KERN_ERR "iter: btree %s pos %s%s%s%s %pS\n",
bch2_btree_ids[iter->btree_id],
(bch2_bpos_to_text(&PBUF(buf), iter->pos), buf),
btree_iter_live(trans, iter) ? " live" : "",
(trans->iters_touched & (1ULL << iter->idx)) ? " touched" : "",
iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT ? " keep" : "",
(void *) iter->ip_allocated);
trans_for_each_update(trans, i) {
char buf[300];
bch2_bkey_val_to_text(&PBUF(buf), trans->c, bkey_i_to_s_c(i->k));
printk(KERN_ERR "update: btree %s %s\n",
bch2_btree_ids[i->iter->btree_id], buf);
}
panic("trans iter oveflow\n");
}
static struct btree_iter *btree_trans_iter_alloc(struct btree_trans *trans)
{
unsigned idx;
if (unlikely(trans->iters_linked ==
~((~0ULL << 1) << (BTREE_ITER_MAX - 1))))
btree_trans_iter_alloc_fail(trans);
idx = __ffs64(~trans->iters_linked);
trans->iters_linked |= 1ULL << idx;
trans->iters[idx].idx = idx;
trans->iters[idx].flags = 0;
return &trans->iters[idx];
}
static inline void btree_iter_copy(struct btree_iter *dst,
struct btree_iter *src)
{
unsigned i, idx = dst->idx;
*dst = *src;
dst->idx = idx;
dst->flags &= ~BTREE_ITER_KEEP_UNTIL_COMMIT;
for (i = 0; i < BTREE_MAX_DEPTH; i++)
if (btree_node_locked(dst, i))
six_lock_increment(&dst->l[i].b->c.lock,
__btree_lock_want(dst, i));
dst->flags &= ~BTREE_ITER_KEEP_UNTIL_COMMIT;
dst->flags &= ~BTREE_ITER_SET_POS_AFTER_COMMIT;
}
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;
if ((flags & BTREE_ITER_TYPE) != BTREE_ITER_NODES &&
!btree_type_has_snapshots(btree_id))
flags &= ~BTREE_ITER_ALL_SNAPSHOTS;
if (!(flags & BTREE_ITER_ALL_SNAPSHOTS))
pos.snapshot = btree_type_has_snapshots(btree_id)
? U32_MAX : 0;
trans_for_each_iter(trans, iter) {
if (btree_iter_type(iter) != (flags & BTREE_ITER_TYPE))
continue;
if (iter->btree_id != btree_id)
continue;
if (best) {
int cmp = bkey_cmp(bpos_diff(best->real_pos, pos),
bpos_diff(iter->real_pos, pos));
if (cmp < 0 ||
((cmp == 0 && btree_iter_keep(trans, iter))))
continue;
}
best = iter;
}
if (!best) {
iter = btree_trans_iter_alloc(trans);
bch2_btree_iter_init(trans, iter, btree_id);
} else if (btree_iter_keep(trans, best)) {
iter = btree_trans_iter_alloc(trans);
btree_iter_copy(iter, best);
} else {
iter = best;
}
trans->iters_live |= 1ULL << iter->idx;
trans->iters_touched |= 1ULL << iter->idx;
if ((flags & BTREE_ITER_TYPE) != BTREE_ITER_NODES &&
btree_node_type_is_extents(btree_id) &&
!(flags & BTREE_ITER_NOT_EXTENTS) &&
!(flags & BTREE_ITER_ALL_SNAPSHOTS))
flags |= BTREE_ITER_IS_EXTENTS;
iter->flags = flags;
iter->snapshot = pos.snapshot;
/*
* If the iterator has locks_want greater than requested, we explicitly
* do not downgrade it here - on transaction restart because btree node
* split needs to upgrade locks, we might be putting/getting the
* iterator again. Downgrading iterators only happens via an explicit
* bch2_trans_downgrade().
*/
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);
}
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));
return iter;
}
struct btree_iter *bch2_trans_get_node_iter(struct btree_trans *trans,
enum btree_id btree_id,
struct bpos pos,
unsigned locks_want,
unsigned depth,
unsigned flags)
{
struct btree_iter *iter =
__bch2_trans_get_iter(trans, btree_id, pos,
locks_want, depth,
BTREE_ITER_NODES|
BTREE_ITER_NOT_EXTENTS|
BTREE_ITER_ALL_SNAPSHOTS|
flags);
BUG_ON(bkey_cmp(iter->pos, pos));
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;
}
struct btree_iter *__bch2_trans_copy_iter(struct btree_trans *trans,
struct btree_iter *src)
{
struct btree_iter *iter;
iter = btree_trans_iter_alloc(trans);
btree_iter_copy(iter, src);
trans->iters_live |= 1ULL << iter->idx;
/*
* We don't need to preserve this iter since it's cheap to copy it
* again - this will cause trans_iter_put() to free it right away:
*/
set_btree_iter_dontneed(trans, iter);
return iter;
}
void *bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
{
size_t new_top = trans->mem_top + size;
void *p;
if (new_top > trans->mem_bytes) {
size_t old_bytes = trans->mem_bytes;
size_t new_bytes = roundup_pow_of_two(new_top);
void *new_mem;
WARN_ON_ONCE(new_bytes > BTREE_TRANS_MEM_MAX);
new_mem = krealloc(trans->mem, new_bytes, GFP_NOFS);
if (!new_mem && new_bytes <= BTREE_TRANS_MEM_MAX) {
new_mem = mempool_alloc(&trans->c->btree_trans_mem_pool, GFP_KERNEL);
new_bytes = BTREE_TRANS_MEM_MAX;
kfree(trans->mem);
}
if (!new_mem)
return ERR_PTR(-ENOMEM);
trans->mem = new_mem;
trans->mem_bytes = new_bytes;
if (old_bytes) {
trace_trans_restart_mem_realloced(trans->ip, _RET_IP_, new_bytes);
return ERR_PTR(-EINTR);
}
}
p = trans->mem + trans->mem_top;
trans->mem_top += size;
return p;
}
inline void bch2_trans_unlink_iters(struct btree_trans *trans)
{
u64 iters = trans->iters_linked &
~trans->iters_touched &
~trans->iters_live;
while (iters) {
unsigned idx = __ffs64(iters);
iters &= ~(1ULL << idx);
__bch2_trans_iter_free(trans, idx);
}
}
void bch2_trans_reset(struct btree_trans *trans, unsigned flags)
{
struct btree_iter *iter;
trans_for_each_iter(trans, iter)
iter->flags &= ~(BTREE_ITER_KEEP_UNTIL_COMMIT|
BTREE_ITER_SET_POS_AFTER_COMMIT);
bch2_trans_unlink_iters(trans);
trans->iters_touched &= trans->iters_live;
trans->nr_updates = 0;
trans->nr_updates2 = 0;
trans->mem_top = 0;
trans->hooks = NULL;
trans->extra_journal_entries = NULL;
trans->extra_journal_entry_u64s = 0;
if (trans->fs_usage_deltas) {
trans->fs_usage_deltas->used = 0;
memset((void *) trans->fs_usage_deltas +
offsetof(struct replicas_delta_list, memset_start), 0,
(void *) &trans->fs_usage_deltas->memset_end -
(void *) &trans->fs_usage_deltas->memset_start);
}
if (!(flags & TRANS_RESET_NOUNLOCK))
bch2_trans_cond_resched(trans);
if (!(flags & TRANS_RESET_NOTRAVERSE) &&
trans->iters_linked)
bch2_btree_iter_traverse_all(trans);
}
static void bch2_trans_alloc_iters(struct btree_trans *trans, struct bch_fs *c)
{
size_t iters_bytes = sizeof(struct btree_iter) * BTREE_ITER_MAX;
size_t updates_bytes = sizeof(struct btree_insert_entry) * BTREE_ITER_MAX;
void *p = NULL;
BUG_ON(trans->used_mempool);
#ifdef __KERNEL__
p = this_cpu_xchg(c->btree_iters_bufs->iter, NULL);
#endif
if (!p)
p = mempool_alloc(&trans->c->btree_iters_pool, GFP_NOFS);
trans->iters = p; p += iters_bytes;
trans->updates = p; p += updates_bytes;
trans->updates2 = p; p += updates_bytes;
}
void bch2_trans_init(struct btree_trans *trans, struct bch_fs *c,
unsigned expected_nr_iters,
size_t expected_mem_bytes)
{
memset(trans, 0, sizeof(*trans));
trans->c = c;
trans->ip = _RET_IP_;
/*
* reallocating iterators currently completely breaks
* bch2_trans_iter_put(), we always allocate the max:
*/
bch2_trans_alloc_iters(trans, c);
if (expected_mem_bytes) {
expected_mem_bytes = roundup_pow_of_two(expected_mem_bytes);
trans->mem = kmalloc(expected_mem_bytes, GFP_KERNEL);
if (!unlikely(trans->mem)) {
trans->mem = mempool_alloc(&c->btree_trans_mem_pool, GFP_KERNEL);
trans->mem_bytes = BTREE_TRANS_MEM_MAX;
} else {
trans->mem_bytes = expected_mem_bytes;
}
}
trans->srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
#ifdef CONFIG_BCACHEFS_DEBUG
trans->pid = current->pid;
mutex_lock(&c->btree_trans_lock);
list_add(&trans->list, &c->btree_trans_list);
mutex_unlock(&c->btree_trans_lock);
#endif
}
int bch2_trans_exit(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
bch2_trans_unlock(trans);
#ifdef CONFIG_BCACHEFS_DEBUG
if (trans->iters_live) {
struct btree_iter *iter;
bch_err(c, "btree iterators leaked!");
trans_for_each_iter(trans, iter)
if (btree_iter_live(trans, iter))
printk(KERN_ERR " btree %s allocated at %pS\n",
bch2_btree_ids[iter->btree_id],
(void *) iter->ip_allocated);
/* Be noisy about this: */
bch2_fatal_error(c);
}
mutex_lock(&trans->c->btree_trans_lock);
list_del(&trans->list);
mutex_unlock(&trans->c->btree_trans_lock);
#endif
srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
bch2_journal_preres_put(&trans->c->journal, &trans->journal_preres);
if (trans->fs_usage_deltas) {
if (trans->fs_usage_deltas->size + sizeof(trans->fs_usage_deltas) ==
REPLICAS_DELTA_LIST_MAX)
mempool_free(trans->fs_usage_deltas,
&trans->c->replicas_delta_pool);
else
kfree(trans->fs_usage_deltas);
}
if (trans->mem_bytes == BTREE_TRANS_MEM_MAX)
mempool_free(trans->mem, &trans->c->btree_trans_mem_pool);
else
kfree(trans->mem);
#ifdef __KERNEL__
/*
* Userspace doesn't have a real percpu implementation:
*/
trans->iters = this_cpu_xchg(c->btree_iters_bufs->iter, trans->iters);
#endif
if (trans->iters)
mempool_free(trans->iters, &trans->c->btree_iters_pool);
trans->mem = (void *) 0x1;
trans->iters = (void *) 0x1;
return trans->error ? -EIO : 0;
}
static void __maybe_unused
bch2_btree_iter_node_to_text(struct printbuf *out,
struct btree_bkey_cached_common *_b,
enum btree_iter_type type)
{
pr_buf(out, " l=%u %s:",
_b->level, bch2_btree_ids[_b->btree_id]);
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;
trans_for_each_iter(trans, iter)
if (btree_iter_type(iter) != BTREE_ITER_CACHED &&
iter->nodes_locked)
return true;
return false;
}
#endif
void bch2_btree_trans_to_text(struct printbuf *out, struct bch_fs *c)
{
#ifdef CONFIG_BCACHEFS_DEBUG
struct btree_trans *trans;
struct btree_iter *iter;
struct btree *b;
unsigned l;
mutex_lock(&c->btree_trans_lock);
list_for_each_entry(trans, &c->btree_trans_list, list) {
if (!trans_has_btree_nodes_locked(trans))
continue;
pr_buf(out, "%i %ps\n", trans->pid, (void *) trans->ip);
trans_for_each_iter(trans, iter) {
if (!iter->nodes_locked)
continue;
pr_buf(out, " iter %u %c %s:",
iter->idx,
btree_iter_type(iter) == BTREE_ITER_CACHED ? 'c' : 'b',
bch2_btree_ids[iter->btree_id]);
bch2_bpos_to_text(out, iter->pos);
pr_buf(out, "\n");
for (l = 0; l < BTREE_MAX_DEPTH; l++) {
if (btree_node_locked(iter, l)) {
pr_buf(out, " %s l=%u ",
btree_node_intent_locked(iter, l) ? "i" : "r", l);
bch2_btree_iter_node_to_text(out,
(void *) iter->l[l].b,
btree_iter_type(iter));
pr_buf(out, "\n");
}
}
}
b = READ_ONCE(trans->locking);
if (b) {
iter = &trans->iters[trans->locking_iter_idx];
pr_buf(out, " locking iter %u %c l=%u %s:",
trans->locking_iter_idx,
btree_iter_type(iter) == BTREE_ITER_CACHED ? 'c' : 'b',
trans->locking_level,
bch2_btree_ids[trans->locking_btree_id]);
bch2_bpos_to_text(out, trans->locking_pos);
pr_buf(out, " node ");
bch2_btree_iter_node_to_text(out,
(void *) b,
btree_iter_type(iter));
pr_buf(out, "\n");
}
}
mutex_unlock(&c->btree_trans_lock);
#endif
}
void bch2_fs_btree_iter_exit(struct bch_fs *c)
{
mempool_exit(&c->btree_trans_mem_pool);
mempool_exit(&c->btree_iters_pool);
cleanup_srcu_struct(&c->btree_trans_barrier);
}
int bch2_fs_btree_iter_init(struct bch_fs *c)
{
unsigned nr = BTREE_ITER_MAX;
INIT_LIST_HEAD(&c->btree_trans_list);
mutex_init(&c->btree_trans_lock);
return init_srcu_struct(&c->btree_trans_barrier) ?:
mempool_init_kmalloc_pool(&c->btree_iters_pool, 1,
sizeof(struct btree_iter) * nr +
sizeof(struct btree_insert_entry) * nr +
sizeof(struct btree_insert_entry) * nr) ?:
mempool_init_kmalloc_pool(&c->btree_trans_mem_pool, 1,
BTREE_TRANS_MEM_MAX);
}
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