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linux/fs/bcachefs/btree_iter.c
Kent Overstreet 0329b1507d bcachefs: Trace where btree iterators are allocated 
This will help with iterator overflow bugs.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:38 -04:00

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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 "btree_update.h"
#include "debug.h"
#include "extents.h"
#include "trace.h"
#include <linux/prefetch.h>
#define BTREE_ITER_NO_NODE_GET_LOCKS ((struct btree *) 1)
#define BTREE_ITER_NO_NODE_DROP ((struct btree *) 2)
#define BTREE_ITER_NO_NODE_LOCK_ROOT ((struct btree *) 3)
#define BTREE_ITER_NO_NODE_UP ((struct btree *) 4)
#define BTREE_ITER_NO_NODE_DOWN ((struct btree *) 5)
#define BTREE_ITER_NO_NODE_INIT ((struct btree *) 6)
#define BTREE_ITER_NO_NODE_ERROR ((struct btree *) 7)
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(pos);
return pos;
}
static inline bool btree_iter_pos_before_node(struct btree_iter *iter,
struct btree *b)
{
return bkey_cmp(btree_iter_search_key(iter), b->data->min_key) < 0;
}
static inline bool btree_iter_pos_after_node(struct btree_iter *iter,
struct btree *b)
{
return bkey_cmp(b->key.k.p, btree_iter_search_key(iter)) < 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:
*/
atomic64_sub(__SIX_VAL(read_lock, readers),
&b->c.lock.state.counter);
btree_node_lock_type(iter->trans->c, b, SIX_LOCK_write);
atomic64_add(__SIX_VAL(read_lock, readers),
&b->c.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 (!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, 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, 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;
}
/* Slowpath: */
bool __bch2_btree_node_lock(struct btree *b, struct bpos pos,
unsigned level,
struct btree_iter *iter,
enum six_lock_type type)
{
struct btree_iter *linked;
bool ret = true;
/* Check if it's safe to block: */
trans_for_each_iter(iter->trans, 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 (!(iter->trans->nounlock)) {
linked->locks_want = max_t(unsigned,
linked->locks_want,
__fls(linked->nodes_locked) + 1);
btree_iter_get_locks(linked, true, false);
}
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 (!(iter->trans->nounlock)) {
linked->locks_want =
max(level + 1, max_t(unsigned,
linked->locks_want,
iter->locks_want));
btree_iter_get_locks(linked, true, false);
}
ret = false;
}
}
if (unlikely(!ret)) {
trace_trans_restart_would_deadlock(iter->trans->ip);
return false;
}
__btree_node_lock_type(iter->trans->c, b, type);
return true;
}
/* Btree iterator locking: */
#ifdef CONFIG_BCACHEFS_DEBUG
static 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));
}
}
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
static 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;
/*
* 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:
*/
trans_for_each_iter(iter->trans, linked)
if (linked != 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;
}
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:
*/
trans_for_each_iter(iter->trans, 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->c.lock);
linked->nodes_intent_locked ^= 1 << l;
}
break;
}
}
}
bch2_btree_trans_verify_locks(iter->trans);
}
/* Btree transaction locking: */
bool bch2_trans_relock(struct btree_trans *trans)
{
struct btree_iter *iter;
bool ret = true;
trans_for_each_iter(trans, iter)
if (iter->uptodate == BTREE_ITER_NEED_RELOCK)
ret &= bch2_btree_iter_relock(iter, true);
return ret;
}
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_level(struct btree_iter *iter,
unsigned level)
{
struct bpos pos = btree_iter_search_key(iter);
struct btree_iter_level *l = &iter->l[level];
struct btree_node_iter tmp = l->iter;
bool locked = btree_node_locked(iter, level);
struct bkey_packed *p, *k;
char buf1[100], buf2[100];
const char *msg;
if (!debug_check_iterators(iter->trans->c))
return;
BUG_ON(iter->level < iter->min_depth);
if (!btree_iter_node(iter, level))
return;
if (!bch2_btree_node_relock(iter, level))
return;
/*
* Ideally this invariant would always be true, and hopefully in the
* future it will be, but for now set_pos_same_leaf() breaks it:
*/
BUG_ON(iter->uptodate < BTREE_ITER_NEED_TRAVERSE &&
!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_filter(&tmp, l->b, KEY_TYPE_discard)
: 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, &pos) >= 0) {
msg = "before";
goto err;
}
if (k && bkey_iter_pos_cmp(l->b, k, &pos) < 0) {
msg = "after";
goto err;
}
unlock:
if (!locked)
btree_node_unlock(iter, level);
return;
err:
strcpy(buf1, "(none)");
strcpy(buf2, "(none)");
if (p) {
struct bkey uk = bkey_unpack_key(l->b, p);
bch2_bkey_to_text(&PBUF(buf1), &uk);
}
if (k) {
struct bkey uk = bkey_unpack_key(l->b, k);
bch2_bkey_to_text(&PBUF(buf2), &uk);
}
panic("iterator should be %s key at level %u:\n"
"iter pos %s %llu:%llu\n"
"prev key %s\n"
"cur key %s\n",
msg, level,
iter->flags & BTREE_ITER_IS_EXTENTS ? ">" : "=>",
iter->pos.inode, iter->pos.offset,
buf1, buf2);
}
static void bch2_btree_iter_verify(struct btree_iter *iter)
{
unsigned i;
bch2_btree_trans_verify_locks(iter->trans);
for (i = 0; i < BTREE_MAX_DEPTH; i++)
bch2_btree_iter_verify_level(iter, i);
}
void bch2_btree_trans_verify_iters(struct btree_trans *trans, struct btree *b)
{
struct btree_iter *iter;
if (!debug_check_iterators(trans->c))
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) {}
#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];
struct bpos pos = btree_iter_search_key(iter);
if (where != bch2_btree_node_iter_peek_all(&l->iter, l->b))
return;
if (bkey_iter_pos_cmp(l->b, where, &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;
struct bpos iter_pos = btree_iter_search_key(iter);
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_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_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 (debug_check_iterators(iter->trans->c))
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 (debug_check_bkeys(iter->trans->c))
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_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 struct bkey_s_c __btree_iter_prev(struct btree_iter *iter,
struct btree_iter_level *l)
{
return __btree_iter_unpack(iter, l, &iter->k,
bch2_btree_node_iter_prev(&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 bpos pos = btree_iter_search_key(iter);
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, &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 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->c.level + 1);
}
static inline void __btree_iter_init(struct btree_iter *iter,
unsigned level)
{
struct bpos pos = btree_iter_search_key(iter);
struct btree_iter_level *l = &iter->l[level];
bch2_btree_node_iter_init(&l->iter, l->b, &pos);
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->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_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 inline int btree_iter_lock_root(struct btree_iter *iter,
unsigned depth_want)
{
struct bch_fs *c = iter->trans->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->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)))
return -EINTR;
if (likely(b == c->btree_roots[iter->btree_id].b &&
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;
BKEY_PADDED(k) 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);
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(c, iter, &tmp.k, iter->level - 1);
}
if (!was_locked)
btree_node_unlock(iter, iter->level);
}
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)
{
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);
BKEY_PADDED(k) tmp;
EBUG_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(c, iter, &tmp.k, level, lock_type);
if (unlikely(IS_ERR(b)))
return PTR_ERR(b);
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;
return 0;
}
static void btree_iter_up(struct btree_iter *iter)
{
btree_node_unlock(iter, iter->level++);
}
static int btree_iter_traverse_one(struct btree_iter *);
static int __btree_iter_traverse_all(struct btree_trans *trans,
struct btree_iter *orig_iter, int ret)
{
struct bch_fs *c = trans->c;
struct btree_iter *iter;
u8 sorted[BTREE_ITER_MAX];
unsigned i, nr_sorted = 0;
trans_for_each_iter(trans, iter)
sorted[nr_sorted++] = iter - trans->iters;
#define btree_iter_cmp_by_idx(_l, _r) \
btree_iter_cmp(&trans->iters[_l], &trans->iters[_r])
bubble_sort(sorted, nr_sorted, btree_iter_cmp_by_idx);
#undef btree_iter_cmp_by_idx
retry_all:
bch2_trans_unlock(trans);
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;
if (orig_iter) {
orig_iter->flags |= BTREE_ITER_ERROR;
orig_iter->l[orig_iter->level].b =
BTREE_ITER_NO_NODE_ERROR;
}
goto out;
}
BUG_ON(ret && ret != -EINTR);
/* Now, redo traversals in correct order: */
for (i = 0; i < nr_sorted; i++) {
iter = &trans->iters[sorted[i]];
ret = btree_iter_traverse_one(iter);
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);
return ret;
}
int bch2_btree_iter_traverse_all(struct btree_trans *trans)
{
return __btree_iter_traverse_all(trans, NULL, 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 depth_want = iter->level;
if (unlikely(iter->level >= BTREE_MAX_DEPTH))
return 0;
/*
* 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 (iter->uptodate < BTREE_ITER_NEED_RELOCK)
return 0;
/*
* XXX: correctly using BTREE_ITER_UPTODATE should make using check_pos
* here unnecessary
*/
iter->level = btree_iter_up_until_good_node(iter, 0);
/*
* 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)) {
BUG_ON(!btree_iter_pos_in_node(iter, iter->l[iter->level].b));
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)) {
if (ret == 1)
return 0;
iter->level = depth_want;
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;
}
int __must_check __bch2_btree_iter_traverse(struct btree_iter *iter)
{
int ret;
ret = bch2_trans_cond_resched(iter->trans) ?:
btree_iter_traverse_one(iter);
if (unlikely(ret))
ret = __btree_iter_traverse_all(iter->trans, iter, ret);
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(btree_iter_type(iter) != type);
BUG_ON(type == BTREE_ITER_KEYS &&
(bkey_cmp(iter->pos, bkey_start_pos(&iter->k)) < 0 ||
bkey_cmp(iter->pos, iter->k.p) > 0));
bch2_btree_iter_verify_locks(iter);
bch2_btree_iter_verify_level(iter, iter->level);
}
/* 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;
bch2_btree_iter_verify(iter);
return b;
}
struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
{
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;
bch2_trans_cond_resched(iter->trans);
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);
iter->pos = bkey_successor(iter->pos);
iter->level = iter->min_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;
bch2_btree_iter_verify(iter);
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);
bkey_init(&iter->k);
iter->k.p = 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);
}
static void btree_iter_pos_changed(struct btree_iter *iter, int cmp)
{
unsigned l = iter->level;
if (!cmp)
goto out;
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);
}
void __bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos,
bool strictly_greater)
{
struct bpos old = btree_iter_search_key(iter);
int cmp;
iter->flags &= ~BTREE_ITER_IS_EXTENTS;
iter->flags |= strictly_greater ? BTREE_ITER_IS_EXTENTS : 0;
bkey_init(&iter->k);
iter->k.p = iter->pos = new_pos;
cmp = bkey_cmp(btree_iter_search_key(iter), old);
btree_iter_pos_changed(iter, cmp);
}
void bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
{
int cmp = bkey_cmp(new_pos, iter->pos);
bkey_init(&iter->k);
iter->k.p = iter->pos = new_pos;
btree_iter_pos_changed(iter, cmp);
}
static inline bool btree_iter_set_pos_to_next_leaf(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
bool ret;
bkey_init(&iter->k);
iter->k.p = iter->pos = l->b->key.k.p;
ret = bkey_cmp(iter->pos, POS_MAX) != 0;
if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
iter->k.p = iter->pos = bkey_successor(iter->pos);
btree_iter_pos_changed(iter, 1);
return ret;
}
static inline bool btree_iter_set_pos_to_prev_leaf(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
bool ret;
bkey_init(&iter->k);
iter->k.p = iter->pos = l->b->data->min_key;
iter->uptodate = BTREE_ITER_NEED_TRAVERSE;
ret = bkey_cmp(iter->pos, POS_MIN) != 0;
if (ret) {
iter->k.p = iter->pos = bkey_predecessor(iter->pos);
if (iter->flags & BTREE_ITER_IS_EXTENTS)
iter->k.p = iter->pos = bkey_predecessor(iter->pos);
}
btree_iter_pos_changed(iter, -1);
return ret;
}
/**
* btree_iter_peek_uptodate - given an iterator that is uptodate, return the key
* it currently points to
*/
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)) {
struct bkey_packed *_k =
__bch2_btree_node_iter_peek_all(&l->iter, l->b);
ret.v = bkeyp_val(&l->b->format, _k);
if (debug_check_iterators(iter->trans->c)) {
struct bkey k = bkey_unpack_key(l->b, _k);
BUG_ON(memcmp(&k, &iter->k, sizeof(k)));
}
if (debug_check_bkeys(iter->trans->c))
bch2_bkey_debugcheck(iter->trans->c, l->b, ret);
}
return ret;
}
/**
* 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)
{
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 &&
!bkey_deleted(&iter->k))
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;
if (!btree_iter_set_pos_to_next_leaf(iter))
return bkey_s_c_null;
}
/*
* 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;
bch2_btree_iter_verify_level(iter, 0);
return k;
}
/**
* 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 (unlikely(!bkey_cmp(iter->k.p, POS_MAX)))
return bkey_s_c_null;
bch2_btree_iter_set_pos(iter,
(iter->flags & BTREE_ITER_IS_EXTENTS)
? iter->k.p
: bkey_successor(iter->k.p));
return bch2_btree_iter_peek(iter);
}
static struct bkey_s_c __btree_trans_updates_peek(struct btree_iter *iter)
{
struct bpos pos = btree_iter_search_key(iter);
struct btree_trans *trans = iter->trans;
struct btree_insert_entry *i;
trans_for_each_update2(trans, i)
if ((cmp_int(iter->btree_id, i->iter->btree_id) ?:
bkey_cmp(pos, i->k->k.p)) <= 0)
break;
return i < trans->updates2 + trans->nr_updates2 &&
iter->btree_id == i->iter->btree_id
? bkey_i_to_s_c(i->k)
: bkey_s_c_null;
}
static struct bkey_s_c __bch2_btree_iter_peek_with_updates(struct btree_iter *iter)
{
struct btree_iter_level *l = &iter->l[0];
struct bkey_s_c k = __btree_iter_peek(iter, l);
struct bkey_s_c u = __btree_trans_updates_peek(iter);
if (k.k && (!u.k || bkey_cmp(k.k->p, u.k->p) < 0))
return k;
if (u.k && bkey_cmp(u.k->p, l->b->key.k.p) <= 0) {
iter->k = *u.k;
return u;
}
return bkey_s_c_null;
}
struct bkey_s_c bch2_btree_iter_peek_with_updates(struct btree_iter *iter)
{
struct bkey_s_c k;
int ret;
bch2_btree_iter_checks(iter, BTREE_ITER_KEYS);
while (1) {
ret = bch2_btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
k = __bch2_btree_iter_peek_with_updates(iter);
if (k.k && bkey_deleted(k.k)) {
bch2_btree_iter_set_pos(iter,
(iter->flags & BTREE_ITER_IS_EXTENTS)
? iter->k.p
: bkey_successor(iter->k.p));
continue;
}
if (likely(k.k))
break;
if (!btree_iter_set_pos_to_next_leaf(iter))
return bkey_s_c_null;
}
/*
* 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;
}
struct bkey_s_c bch2_btree_iter_next_with_updates(struct btree_iter *iter)
{
if (unlikely(!bkey_cmp(iter->k.p, POS_MAX)))
return bkey_s_c_null;
bch2_btree_iter_set_pos(iter,
(iter->flags & BTREE_ITER_IS_EXTENTS)
? iter->k.p
: bkey_successor(iter->k.p));
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 bpos pos = iter->pos;
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 &&
!bkey_deleted(&iter->k))
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 (!k.k || bkey_cmp(bkey_start_pos(k.k), pos) > 0)
k = __btree_iter_prev(iter, l);
if (likely(k.k))
break;
if (!btree_iter_set_pos_to_prev_leaf(iter))
return bkey_s_c_null;
}
EBUG_ON(bkey_cmp(bkey_start_pos(k.k), pos) > 0);
iter->pos = bkey_start_pos(k.k);
iter->uptodate = BTREE_ITER_UPTODATE;
return k;
}
/**
* 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)
{
struct bpos pos = bkey_start_pos(&iter->k);
bch2_btree_iter_checks(iter, BTREE_ITER_KEYS);
if (unlikely(!bkey_cmp(pos, POS_MIN)))
return bkey_s_c_null;
bch2_btree_iter_set_pos(iter, bkey_predecessor(pos));
return bch2_btree_iter_peek_prev(iter);
}
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;
/* 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->pos));
ret = bch2_btree_iter_traverse(iter);
if (unlikely(ret))
return bkey_s_c_err(ret);
}
/*
* 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;
k = __btree_iter_unpack(iter, l, &iter->k,
bch2_btree_node_iter_peek(&node_iter, l->b));
if (k.k && bkey_cmp(bkey_start_pos(k.k), iter->pos) <= 0) {
/*
* We're not setting iter->uptodate because the node iterator
* doesn't necessarily point at the key we're returning:
*/
EBUG_ON(bkey_cmp(k.k->p, iter->pos) <= 0);
bch2_btree_iter_verify_level(iter, 0);
return k;
}
/* hole */
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;
bch2_btree_iter_verify_level(iter, 0);
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;
bch2_btree_iter_checks(iter, BTREE_ITER_KEYS);
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);
if (iter->flags & BTREE_ITER_IS_EXTENTS)
return __bch2_btree_iter_peek_slot_extents(iter);
k = __btree_iter_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 };
}
iter->uptodate = BTREE_ITER_UPTODATE;
bch2_btree_iter_verify_level(iter, 0);
return k;
}
struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *iter)
{
if (unlikely(!bkey_cmp(iter->k.p, POS_MAX)))
return bkey_s_c_null;
bch2_btree_iter_set_pos(iter,
(iter->flags & BTREE_ITER_IS_EXTENTS)
? iter->k.p
: bkey_successor(iter->k.p));
return bch2_btree_iter_peek_slot(iter);
}
static inline void bch2_btree_iter_init(struct btree_trans *trans,
struct btree_iter *iter, enum btree_id btree_id,
struct bpos pos, unsigned flags)
{
struct bch_fs *c = trans->c;
unsigned i;
if (btree_node_type_is_extents(btree_id) &&
!(flags & BTREE_ITER_NODES))
flags |= BTREE_ITER_IS_EXTENTS;
iter->trans = trans;
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 = 0;
iter->min_depth = 0;
iter->locks_want = flags & BTREE_ITER_INTENT ? 1 : 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);
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;
trans->iters_touched &= ~(1ULL << iter->idx);
return bch2_trans_iter_put(trans, iter);
}
static int bch2_trans_realloc_iters(struct btree_trans *trans,
unsigned new_size)
{
void *p, *new_iters, *new_updates, *new_updates2;
size_t iters_bytes;
size_t updates_bytes;
new_size = roundup_pow_of_two(new_size);
BUG_ON(new_size > BTREE_ITER_MAX);
if (new_size <= trans->size)
return 0;
BUG_ON(trans->used_mempool);
bch2_trans_unlock(trans);
iters_bytes = sizeof(struct btree_iter) * new_size;
updates_bytes = sizeof(struct btree_insert_entry) * new_size;
p = kmalloc(iters_bytes +
updates_bytes +
updates_bytes, GFP_NOFS);
if (p)
goto success;
p = mempool_alloc(&trans->c->btree_iters_pool, GFP_NOFS);
new_size = BTREE_ITER_MAX;
trans->used_mempool = true;
success:
new_iters = p; p += iters_bytes;
new_updates = p; p += updates_bytes;
new_updates2 = p; p += updates_bytes;
memcpy(new_iters, trans->iters,
sizeof(struct btree_iter) * trans->nr_iters);
memcpy(new_updates, trans->updates,
sizeof(struct btree_insert_entry) * trans->nr_updates);
memcpy(new_updates2, trans->updates2,
sizeof(struct btree_insert_entry) * trans->nr_updates2);
if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG))
memset(trans->iters, POISON_FREE,
sizeof(struct btree_iter) * trans->nr_iters +
sizeof(struct btree_insert_entry) * trans->nr_iters);
if (trans->iters != trans->iters_onstack)
kfree(trans->iters);
trans->iters = new_iters;
trans->updates = new_updates;
trans->updates2 = new_updates2;
trans->size = new_size;
if (trans->iters_live) {
trace_trans_restart_iters_realloced(trans->ip, trans->size);
return -EINTR;
}
return 0;
}
static struct btree_iter *btree_trans_iter_alloc(struct btree_trans *trans)
{
unsigned idx = __ffs64(~trans->iters_linked);
if (idx < trans->nr_iters)
goto got_slot;
if (trans->nr_iters == trans->size) {
int ret;
if (trans->nr_iters >= BTREE_ITER_MAX) {
struct btree_iter *iter;
trans_for_each_iter(trans, iter) {
pr_err("iter: btree %s pos %llu:%llu%s%s%s %pf",
bch2_btree_ids[iter->btree_id],
iter->pos.inode,
iter->pos.offset,
(trans->iters_live & (1ULL << iter->idx)) ? " live" : "",
(trans->iters_touched & (1ULL << iter->idx)) ? " touched" : "",
iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT ? " keep" : "",
(void *) iter->ip_allocated);
}
panic("trans iter oveflow\n");
}
ret = bch2_trans_realloc_iters(trans, trans->size * 2);
if (ret)
return ERR_PTR(ret);
}
idx = trans->nr_iters++;
BUG_ON(trans->nr_iters > trans->size);
trans->iters[idx].idx = idx;
got_slot:
BUG_ON(trans->iters_linked & (1ULL << idx));
trans->iters_linked |= 1ULL << 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;
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;
}
static inline struct bpos bpos_diff(struct bpos l, struct bpos r)
{
if (bkey_cmp(l, r) > 0)
swap(l, r);
return POS(r.inode - l.inode, r.offset - l.offset);
}
static struct btree_iter *__btree_trans_get_iter(struct btree_trans *trans,
unsigned btree_id, struct bpos pos,
unsigned flags)
{
struct btree_iter *iter, *best = NULL;
BUG_ON(trans->nr_iters > BTREE_ITER_MAX);
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 &&
bkey_cmp(bpos_diff(best->pos, pos),
bpos_diff(iter->pos, pos)) < 0)
continue;
best = iter;
}
if (!best) {
iter = btree_trans_iter_alloc(trans);
if (IS_ERR(iter))
return iter;
bch2_btree_iter_init(trans, iter, btree_id, pos, flags);
} else if ((trans->iters_live & (1ULL << best->idx)) ||
(best->flags & BTREE_ITER_KEEP_UNTIL_COMMIT)) {
iter = btree_trans_iter_alloc(trans);
if (IS_ERR(iter))
return iter;
btree_iter_copy(iter, best);
} else {
iter = best;
}
iter->flags &= ~(BTREE_ITER_SLOTS|BTREE_ITER_INTENT|BTREE_ITER_PREFETCH);
iter->flags |= flags & (BTREE_ITER_SLOTS|BTREE_ITER_INTENT|BTREE_ITER_PREFETCH);
if (iter->flags & BTREE_ITER_INTENT)
bch2_btree_iter_upgrade(iter, 1);
else
bch2_btree_iter_downgrade(iter);
BUG_ON(iter->btree_id != btree_id);
BUG_ON((iter->flags ^ flags) & BTREE_ITER_TYPE);
BUG_ON(iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT);
BUG_ON(iter->flags & BTREE_ITER_SET_POS_AFTER_COMMIT);
BUG_ON(trans->iters_live & (1ULL << iter->idx));
trans->iters_live |= 1ULL << iter->idx;
trans->iters_touched |= 1ULL << iter->idx;
return iter;
}
struct btree_iter *__bch2_trans_get_iter(struct btree_trans *trans,
enum btree_id btree_id,
struct bpos pos, unsigned flags)
{
struct btree_iter *iter =
__btree_trans_get_iter(trans, btree_id, pos, flags);
if (!IS_ERR(iter))
__bch2_btree_iter_set_pos(iter, pos,
btree_node_type_is_extents(btree_id));
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 =
__btree_trans_get_iter(trans, btree_id, pos,
flags|BTREE_ITER_NODES);
unsigned i;
BUG_ON(IS_ERR(iter));
BUG_ON(bkey_cmp(iter->pos, pos));
iter->locks_want = locks_want;
iter->level = depth;
iter->min_depth = depth;
for (i = 0; i < ARRAY_SIZE(iter->l); i++)
iter->l[i].b = NULL;
iter->l[iter->level].b = BTREE_ITER_NO_NODE_INIT;
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);
if (IS_ERR(iter))
return iter;
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:
*/
trans->iters_touched &= ~(1ULL << iter->idx);
return iter;
}
static int bch2_trans_preload_mem(struct btree_trans *trans, size_t size)
{
if (size > trans->mem_bytes) {
size_t old_bytes = trans->mem_bytes;
size_t new_bytes = roundup_pow_of_two(size);
void *new_mem = krealloc(trans->mem, new_bytes, GFP_NOFS);
if (!new_mem)
return -ENOMEM;
trans->mem = new_mem;
trans->mem_bytes = new_bytes;
if (old_bytes) {
trace_trans_restart_mem_realloced(trans->ip, new_bytes);
return -EINTR;
}
}
return 0;
}
void *bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
{
void *p;
int ret;
ret = bch2_trans_preload_mem(trans, trans->mem_top + size);
if (ret)
return ERR_PTR(ret);
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->need_reset = 0;
trans->nr_updates = 0;
trans->nr_updates2 = 0;
trans->mem_top = 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_NOTRAVERSE))
bch2_btree_iter_traverse_all(trans);
}
void bch2_trans_init(struct btree_trans *trans, struct bch_fs *c,
unsigned expected_nr_iters,
size_t expected_mem_bytes)
{
memset(trans, 0, offsetof(struct btree_trans, iters_onstack));
/*
* reallocating iterators currently completely breaks
* bch2_trans_iter_put():
*/
expected_nr_iters = BTREE_ITER_MAX;
trans->c = c;
trans->ip = _RET_IP_;
trans->size = ARRAY_SIZE(trans->iters_onstack);
trans->iters = trans->iters_onstack;
trans->updates = trans->updates_onstack;
trans->updates2 = trans->updates2_onstack;
trans->fs_usage_deltas = NULL;
if (expected_nr_iters > trans->size)
bch2_trans_realloc_iters(trans, expected_nr_iters);
if (expected_mem_bytes)
bch2_trans_preload_mem(trans, expected_mem_bytes);
}
int bch2_trans_exit(struct btree_trans *trans)
{
bch2_trans_unlock(trans);
kfree(trans->fs_usage_deltas);
kfree(trans->mem);
if (trans->used_mempool)
mempool_free(trans->iters, &trans->c->btree_iters_pool);
else if (trans->iters != trans->iters_onstack)
kfree(trans->iters);
trans->mem = (void *) 0x1;
trans->iters = (void *) 0x1;
return trans->error ? -EIO : 0;
}
void bch2_fs_btree_iter_exit(struct bch_fs *c)
{
mempool_exit(&c->btree_iters_pool);
}
int bch2_fs_btree_iter_init(struct bch_fs *c)
{
unsigned nr = BTREE_ITER_MAX;
return 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);
}
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