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33aa419db9
linux/fs/bcachefs/btree_iter.c
Kent Overstreet 33aa419db9 bcachefs: Fix __btree_path_traverse_all 
The loop that traverses paths in traverse_all() needs to be a little bit
tricky, because traversing a path can cause other paths to be added (or
perhaps removed) at about the same position.

The old logic was buggy, replace it with simpler logic.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:24 -04:00

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81 KiB
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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 "recovery.h"
#include "replicas.h"
#include "subvolume.h"
#include "trace.h"
#include <linux/prefetch.h>
static inline void btree_path_list_remove(struct btree_trans *, struct btree_path *);
static inline void btree_path_list_add(struct btree_trans *, struct btree_path *,
struct btree_path *);
static struct btree_path *btree_path_alloc(struct btree_trans *, struct btree_path *);
/*
* Unlocks before scheduling
* Note: does not revalidate iterator
*/
static inline int bch2_trans_cond_resched(struct btree_trans *trans)
{
if (need_resched() || race_fault()) {
bch2_trans_unlock(trans);
schedule();
return bch2_trans_relock(trans) ? 0 : -EINTR;
} else {
return 0;
}
}
static inline int __btree_path_cmp(const struct btree_path *l,
enum btree_id r_btree_id,
bool r_cached,
struct bpos r_pos,
unsigned r_level)
{
/*
* Must match lock ordering as defined by __bch2_btree_node_lock:
*/
return cmp_int(l->btree_id, r_btree_id) ?:
cmp_int((int) l->cached, (int) r_cached) ?:
bpos_cmp(l->pos, r_pos) ?:
-cmp_int(l->level, r_level);
}
static inline int btree_path_cmp(const struct btree_path *l,
const struct btree_path *r)
{
return __btree_path_cmp(l, r->btree_id, r->cached, r->pos, r->level);
}
static inline struct bpos bkey_successor(struct btree_iter *iter, struct bpos p)
{
/* 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)
{
/* 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_path *path, unsigned l)
{
return l < BTREE_MAX_DEPTH &&
(unsigned long) path->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_path_pos_before_node(struct btree_path *path,
struct btree *b)
{
return bpos_cmp(path->pos, b->data->min_key) < 0;
}
static inline bool btree_path_pos_after_node(struct btree_path *path,
struct btree *b)
{
return bpos_cmp(b->key.k.p, path->pos) < 0;
}
static inline bool btree_path_pos_in_node(struct btree_path *path,
struct btree *b)
{
return path->btree_id == b->c.btree_id &&
!btree_path_pos_before_node(path, b) &&
!btree_path_pos_after_node(path, b);
}
/* Btree node locking: */
void bch2_btree_node_unlock_write(struct btree_trans *trans,
struct btree_path *path, struct btree *b)
{
bch2_btree_node_unlock_write_inlined(trans, path, b);
}
void __bch2_btree_node_lock_write(struct btree_trans *trans, struct btree *b)
{
struct btree_path *linked;
unsigned readers = 0;
trans_for_each_path(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);
six_lock_write(&b->c.lock, NULL, NULL);
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_trans *trans,
struct btree_path *path, unsigned level)
{
struct btree *b = btree_path_node(path, level);
int want = __btree_lock_want(path, level);
if (!is_btree_node(path, level))
goto fail;
if (race_fault())
goto fail;
if (six_relock_type(&b->c.lock, want, path->l[level].lock_seq) ||
(btree_node_lock_seq_matches(path, b, level) &&
btree_node_lock_increment(trans, b, level, want))) {
mark_btree_node_locked(path, level, want);
return true;
}
fail:
trace_btree_node_relock_fail(trans->fn, _RET_IP_,
path->btree_id,
&path->pos,
(unsigned long) b,
path->l[level].lock_seq,
is_btree_node(path, level) ? b->c.lock.state.seq : 0);
return false;
}
bool bch2_btree_node_upgrade(struct btree_trans *trans,
struct btree_path *path, unsigned level)
{
struct btree *b = path->l[level].b;
if (!is_btree_node(path, level))
return false;
switch (btree_lock_want(path, level)) {
case BTREE_NODE_UNLOCKED:
BUG_ON(btree_node_locked(path, level));
return true;
case BTREE_NODE_READ_LOCKED:
BUG_ON(btree_node_intent_locked(path, level));
return bch2_btree_node_relock(trans, path, level);
case BTREE_NODE_INTENT_LOCKED:
break;
}
if (btree_node_intent_locked(path, level))
return true;
if (race_fault())
return false;
if (btree_node_locked(path, level)
? six_lock_tryupgrade(&b->c.lock)
: six_relock_type(&b->c.lock, SIX_LOCK_intent, path->l[level].lock_seq))
goto success;
if (btree_node_lock_seq_matches(path, b, level) &&
btree_node_lock_increment(trans, b, level, BTREE_NODE_INTENT_LOCKED)) {
btree_node_unlock(path, level);
goto success;
}
return false;
success:
mark_btree_node_intent_locked(path, level);
return true;
}
static inline bool btree_path_get_locks(struct btree_trans *trans,
struct btree_path *path,
bool upgrade)
{
unsigned l = path->level;
int fail_idx = -1;
do {
if (!btree_path_node(path, l))
break;
if (!(upgrade
? bch2_btree_node_upgrade(trans, path, l)
: bch2_btree_node_relock(trans, path, l)))
fail_idx = l;
l++;
} while (l < path->locks_want);
/*
* When we fail to get a lock, we have to ensure that any child nodes
* can't be relocked so bch2_btree_path_traverse has to walk back up to
* the node that we failed to relock:
*/
if (fail_idx >= 0) {
__bch2_btree_path_unlock(path);
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
do {
path->l[fail_idx].b = BTREE_ITER_NO_NODE_GET_LOCKS;
--fail_idx;
} while (fail_idx >= 0);
}
if (path->uptodate == BTREE_ITER_NEED_RELOCK)
path->uptodate = BTREE_ITER_UPTODATE;
bch2_trans_verify_locks(trans);
return path->uptodate < BTREE_ITER_NEED_RELOCK;
}
static struct bpos btree_node_pos(struct btree_bkey_cached_common *_b,
bool cached)
{
return !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_trans *trans,
struct btree_path *path,
struct btree *b,
struct bpos pos, unsigned level,
enum six_lock_type type,
six_lock_should_sleep_fn should_sleep_fn, void *p,
unsigned long ip)
{
struct btree_path *linked;
unsigned reason;
/* Check if it's safe to block: */
trans_for_each_path(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) {
reason = 1;
goto deadlock;
}
if (linked->btree_id != path->btree_id) {
if (linked->btree_id < path->btree_id)
continue;
reason = 3;
goto deadlock;
}
/*
* Within the same btree, non-cached paths come before cached
* paths:
*/
if (linked->cached != path->cached) {
if (!linked->cached)
continue;
reason = 4;
goto deadlock;
}
/*
* Interior nodes must be locked before their descendants: if
* another path 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)) {
reason = 5;
goto deadlock;
}
/* Must lock btree nodes in key order: */
if (btree_node_locked(linked, level) &&
bpos_cmp(pos, btree_node_pos((void *) linked->l[level].b,
linked->cached)) <= 0) {
reason = 7;
goto deadlock;
}
}
return btree_node_lock_type(trans, path, b, pos, level,
type, should_sleep_fn, p);
deadlock:
trace_trans_restart_would_deadlock(trans->fn, ip,
trans->in_traverse_all, reason,
linked->btree_id,
linked->cached,
&linked->pos,
path->btree_id,
path->cached,
&pos);
btree_trans_restart(trans);
return false;
}
/* Btree iterator locking: */
#ifdef CONFIG_BCACHEFS_DEBUG
static void bch2_btree_path_verify_locks(struct btree_path *path)
{
unsigned l;
if (!path->nodes_locked) {
BUG_ON(path->uptodate == BTREE_ITER_UPTODATE &&
btree_path_node(path, path->level));
return;
}
for (l = 0; btree_path_node(path, l); l++)
BUG_ON(btree_lock_want(path, l) !=
btree_node_locked_type(path, l));
}
void bch2_trans_verify_locks(struct btree_trans *trans)
{
struct btree_path *path;
trans_for_each_path(trans, path)
bch2_btree_path_verify_locks(path);
}
#else
static inline void bch2_btree_path_verify_locks(struct btree_path *path) {}
#endif
/* Btree path locking: */
/*
* Only for btree_cache.c - only relocks intent locks
*/
bool bch2_btree_path_relock_intent(struct btree_trans *trans,
struct btree_path *path)
{
unsigned l;
for (l = path->level;
l < path->locks_want && btree_path_node(path, l);
l++) {
if (!bch2_btree_node_relock(trans, path, l)) {
__bch2_btree_path_unlock(path);
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
trace_trans_restart_relock_path_intent(trans->fn, _RET_IP_,
path->btree_id, &path->pos);
btree_trans_restart(trans);
return false;
}
}
return true;
}
__flatten
static bool bch2_btree_path_relock(struct btree_trans *trans,
struct btree_path *path, unsigned long trace_ip)
{
bool ret = btree_path_get_locks(trans, path, false);
if (!ret) {
trace_trans_restart_relock_path(trans->fn, trace_ip,
path->btree_id, &path->pos);
btree_trans_restart(trans);
}
return ret;
}
bool __bch2_btree_path_upgrade(struct btree_trans *trans,
struct btree_path *path,
unsigned new_locks_want)
{
struct btree_path *linked;
EBUG_ON(path->locks_want >= new_locks_want);
path->locks_want = new_locks_want;
if (btree_path_get_locks(trans, path, 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_path_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_path_traverse_all().
*/
trans_for_each_path(trans, linked)
if (linked != path &&
linked->cached == path->cached &&
linked->btree_id == path->btree_id &&
linked->locks_want < new_locks_want) {
linked->locks_want = new_locks_want;
btree_path_get_locks(trans, linked, true);
}
return false;
}
void __bch2_btree_path_downgrade(struct btree_path *path,
unsigned new_locks_want)
{
unsigned l;
EBUG_ON(path->locks_want < new_locks_want);
path->locks_want = new_locks_want;
while (path->nodes_locked &&
(l = __fls(path->nodes_locked)) >= path->locks_want) {
if (l > path->level) {
btree_node_unlock(path, l);
} else {
if (btree_node_intent_locked(path, l)) {
six_lock_downgrade(&path->l[l].b->c.lock);
path->nodes_intent_locked ^= 1 << l;
}
break;
}
}
bch2_btree_path_verify_locks(path);
}
void bch2_trans_downgrade(struct btree_trans *trans)
{
struct btree_path *path;
trans_for_each_path(trans, path)
bch2_btree_path_downgrade(path);
}
/* Btree transaction locking: */
bool bch2_trans_relock(struct btree_trans *trans)
{
struct btree_path *path;
if (unlikely(trans->restarted))
return false;
trans_for_each_path(trans, path)
if (path->should_be_locked &&
!bch2_btree_path_relock(trans, path, _RET_IP_)) {
trace_trans_restart_relock(trans->fn, _RET_IP_,
path->btree_id, &path->pos);
BUG_ON(!trans->restarted);
return false;
}
return true;
}
void bch2_trans_unlock(struct btree_trans *trans)
{
struct btree_path *path;
trans_for_each_path(trans, path)
__bch2_btree_path_unlock(path);
}
/* Btree iterator: */
#ifdef CONFIG_BCACHEFS_DEBUG
static void bch2_btree_path_verify_cached(struct btree_trans *trans,
struct btree_path *path)
{
struct bkey_cached *ck;
bool locked = btree_node_locked(path, 0);
if (!bch2_btree_node_relock(trans, path, 0))
return;
ck = (void *) path->l[0].b;
BUG_ON(ck->key.btree_id != path->btree_id ||
bkey_cmp(ck->key.pos, path->pos));
if (!locked)
btree_node_unlock(path, 0);
}
static void bch2_btree_path_verify_level(struct btree_trans *trans,
struct btree_path *path, unsigned level)
{
struct btree_path_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 = &path->l[level];
tmp = l->iter;
locked = btree_node_locked(path, level);
if (path->cached) {
if (!level)
bch2_btree_path_verify_cached(trans, path);
return;
}
if (!btree_path_node(path, level))
return;
if (!bch2_btree_node_relock(trans, path, level))
return;
BUG_ON(!btree_path_pos_in_node(path, l->b));
bch2_btree_node_iter_verify(&l->iter, l->b);
/*
* For interior nodes, the iterator will have skipped past deleted keys:
*/
p = level
? 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, &path->pos) >= 0) {
msg = "before";
goto err;
}
if (k && bkey_iter_pos_cmp(l->b, k, &path->pos) < 0) {
msg = "after";
goto err;
}
if (!locked)
btree_node_unlock(path, level);
return;
err:
strcpy(buf2, "(none)");
strcpy(buf3, "(none)");
bch2_bpos_to_text(&PBUF(buf1), path->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("path should be %s key at level %u:\n"
"path pos %s\n"
"prev key %s\n"
"cur key %s\n",
msg, level, buf1, buf2, buf3);
}
static void bch2_btree_path_verify(struct btree_trans *trans,
struct btree_path *path)
{
struct bch_fs *c = trans->c;
unsigned i;
EBUG_ON(path->btree_id >= BTREE_ID_NR);
for (i = 0; i < (!path->cached ? BTREE_MAX_DEPTH : 1); i++) {
if (!path->l[i].b) {
BUG_ON(!path->cached &&
c->btree_roots[path->btree_id].b->c.level > i);
break;
}
bch2_btree_path_verify_level(trans, path, i);
}
bch2_btree_path_verify_locks(path);
}
void bch2_trans_verify_paths(struct btree_trans *trans)
{
struct btree_path *path;
trans_for_each_path(trans, path)
bch2_btree_path_verify(trans, path);
}
static void bch2_btree_iter_verify(struct btree_iter *iter)
{
struct btree_trans *trans = iter->trans;
BUG_ON(iter->btree_id >= BTREE_ID_NR);
BUG_ON(!!(iter->flags & BTREE_ITER_CACHED) != iter->path->cached);
BUG_ON((iter->flags & BTREE_ITER_IS_EXTENTS) &&
(iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
BUG_ON(!(iter->flags & __BTREE_ITER_ALL_SNAPSHOTS) &&
(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
!btree_type_has_snapshots(iter->btree_id));
if (iter->update_path)
bch2_btree_path_verify(trans, iter->update_path);
bch2_btree_path_verify(trans, iter->path);
}
static void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter)
{
BUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
!iter->pos.snapshot);
BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
iter->pos.snapshot != iter->snapshot);
BUG_ON(bkey_cmp(iter->pos, bkey_start_pos(&iter->k)) < 0 ||
bkey_cmp(iter->pos, iter->k.p) > 0);
}
static int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k)
{
struct btree_trans *trans = iter->trans;
struct btree_iter copy;
struct bkey_s_c prev;
int ret = 0;
if (!bch2_debug_check_iterators)
return 0;
if (!(iter->flags & BTREE_ITER_FILTER_SNAPSHOTS))
return 0;
if (bkey_err(k) || !k.k)
return 0;
BUG_ON(!bch2_snapshot_is_ancestor(trans->c,
iter->snapshot,
k.k->p.snapshot));
bch2_trans_iter_init(trans, &copy, iter->btree_id, iter->pos,
BTREE_ITER_NOPRESERVE|
BTREE_ITER_ALL_SNAPSHOTS);
prev = bch2_btree_iter_prev(&copy);
if (!prev.k)
goto out;
ret = bkey_err(prev);
if (ret)
goto out;
if (!bkey_cmp(prev.k->p, k.k->p) &&
bch2_snapshot_is_ancestor(trans->c, iter->snapshot,
prev.k->p.snapshot) > 0) {
char buf1[100], buf2[200];
bch2_bkey_to_text(&PBUF(buf1), k.k);
bch2_bkey_to_text(&PBUF(buf2), prev.k);
panic("iter snap %u\n"
"k %s\n"
"prev %s\n",
iter->snapshot,
buf1, buf2);
}
out:
bch2_trans_iter_exit(trans, &copy);
return ret;
}
void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
struct bpos pos, bool key_cache)
{
struct btree_path *path;
unsigned idx;
char buf[100];
trans_for_each_path_inorder(trans, path, idx) {
int cmp = cmp_int(path->btree_id, id) ?:
cmp_int(path->cached, key_cache);
if (cmp > 0)
break;
if (cmp < 0)
continue;
if (!(path->nodes_locked & 1) ||
!path->should_be_locked)
continue;
if (!key_cache) {
if (bkey_cmp(pos, path->l[0].b->data->min_key) >= 0 &&
bkey_cmp(pos, path->l[0].b->key.k.p) <= 0)
return;
} else {
if (!bkey_cmp(pos, path->pos))
return;
}
}
bch2_dump_trans_paths_updates(trans);
panic("not locked: %s %s%s\n",
bch2_btree_ids[id],
(bch2_bpos_to_text(&PBUF(buf), pos), buf),
key_cache ? " cached" : "");
}
#else
static inline void bch2_btree_path_verify_level(struct btree_trans *trans,
struct btree_path *path, unsigned l) {}
static inline void bch2_btree_path_verify(struct btree_trans *trans,
struct btree_path *path) {}
static inline void bch2_btree_iter_verify(struct btree_iter *iter) {}
static inline void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter) {}
static inline int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k) { return 0; }
#endif
/* Btree path: fixups after btree updates */
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_path_fix_key_modified(struct btree_path *path,
struct btree *b,
struct bkey_packed *where)
{
struct btree_path_level *l = &path->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, &path->pos) < 0)
bch2_btree_node_iter_advance(&l->iter, l->b);
}
void bch2_btree_path_fix_key_modified(struct btree_trans *trans,
struct btree *b,
struct bkey_packed *where)
{
struct btree_path *path;
trans_for_each_path_with_node(trans, b, path) {
__bch2_btree_path_fix_key_modified(path, b, where);
bch2_btree_path_verify_level(trans, path, b->c.level);
}
}
static void __bch2_btree_node_iter_fix(struct btree_path *path,
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, &path->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, &path->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) {
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);
}
}
}
void bch2_btree_node_iter_fix(struct btree_trans *trans,
struct btree_path *path,
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_path *linked;
if (node_iter != &path->l[b->c.level].iter) {
__bch2_btree_node_iter_fix(path, 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_path_with_node(trans, b, linked) {
__bch2_btree_node_iter_fix(linked, b,
&linked->l[b->c.level].iter, t,
where, clobber_u64s, new_u64s);
bch2_btree_path_verify_level(trans, linked, b->c.level);
}
}
/* Btree path level: pointer to a particular btree node and node iter */
static inline struct bkey_s_c __btree_iter_unpack(struct bch_fs *c,
struct btree_path_level *l,
struct bkey *u,
struct bkey_packed *k)
{
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;
}
return bkey_disassemble(l->b, k, u);
}
static inline struct bkey_s_c btree_path_level_peek_all(struct bch_fs *c,
struct btree_path_level *l,
struct bkey *u)
{
return __btree_iter_unpack(c, l, u,
bch2_btree_node_iter_peek_all(&l->iter, l->b));
}
static inline struct bkey_s_c btree_path_level_peek(struct btree_trans *trans,
struct btree_path *path,
struct btree_path_level *l,
struct bkey *u)
{
struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,
bch2_btree_node_iter_peek(&l->iter, l->b));
path->pos = k.k ? k.k->p : l->b->key.k.p;
trans->paths_sorted = false;
return k;
}
static inline struct bkey_s_c btree_path_level_prev(struct btree_trans *trans,
struct btree_path *path,
struct btree_path_level *l,
struct bkey *u)
{
struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,
bch2_btree_node_iter_prev(&l->iter, l->b));
path->pos = k.k ? k.k->p : l->b->data->min_key;
trans->paths_sorted = false;
return k;
}
static inline bool btree_path_advance_to_pos(struct btree_path *path,
struct btree_path_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, &path->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_path_verify_new_node(struct btree_trans *trans,
struct btree_path *path, struct btree *b)
{
struct bch_fs *c = trans->c;
struct btree_path_level *l;
unsigned plevel;
bool parent_locked;
struct bkey_packed *k;
if (!IS_ENABLED(CONFIG_BCACHEFS_DEBUG))
return;
if (trans->journal_replay_not_finished)
return;
plevel = b->c.level + 1;
if (!btree_path_node(path, plevel))
return;
parent_locked = btree_node_locked(path, plevel);
if (!bch2_btree_node_relock(trans, path, plevel))
return;
l = &path->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(c, l->b);
bch2_bpos_to_text(&PBUF(buf1), path->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[path->btree_id], buf1,
buf2, buf3, buf4);
}
if (!parent_locked)
btree_node_unlock(path, plevel);
}
static inline void __btree_path_level_init(struct btree_path *path,
unsigned level)
{
struct btree_path_level *l = &path->l[level];
bch2_btree_node_iter_init(&l->iter, l->b, &path->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);
}
static inline void btree_path_level_init(struct btree_trans *trans,
struct btree_path *path,
struct btree *b)
{
BUG_ON(path->cached);
btree_path_verify_new_node(trans, path, b);
EBUG_ON(!btree_path_pos_in_node(path, b));
EBUG_ON(b->c.lock.state.seq & 1);
path->l[b->c.level].lock_seq = b->c.lock.state.seq;
path->l[b->c.level].b = b;
__btree_path_level_init(path, b->c.level);
}
/* Btree path: fixups after btree node updates: */
/*
* A btree node is being replaced - update the iterator to point to the new
* node:
*/
void bch2_trans_node_add(struct btree_trans *trans, struct btree *b)
{
struct btree_path *path;
trans_for_each_path(trans, path)
if (!path->cached &&
btree_path_pos_in_node(path, b)) {
enum btree_node_locked_type t =
btree_lock_want(path, b->c.level);
if (path->nodes_locked &&
t != BTREE_NODE_UNLOCKED) {
btree_node_unlock(path, b->c.level);
six_lock_increment(&b->c.lock, (enum six_lock_type) t);
mark_btree_node_locked(path, b->c.level, (enum six_lock_type) t);
}
btree_path_level_init(trans, path, b);
}
}
/*
* A btree node has been modified in such a way as to invalidate iterators - fix
* them:
*/
void bch2_trans_node_reinit_iter(struct btree_trans *trans, struct btree *b)
{
struct btree_path *path;
trans_for_each_path_with_node(trans, b, path)
__btree_path_level_init(path, b->c.level);
}
/* Btree path: traverse, set_pos: */
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_path_lock_root(struct btree_trans *trans,
struct btree_path *path,
unsigned depth_want,
unsigned long trace_ip)
{
struct bch_fs *c = trans->c;
struct btree *b, **rootp = &c->btree_roots[path->btree_id].b;
enum six_lock_type lock_type;
unsigned i;
EBUG_ON(path->nodes_locked);
while (1) {
b = READ_ONCE(*rootp);
path->level = READ_ONCE(b->c.level);
if (unlikely(path->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
*/
path->level = depth_want;
for (i = path->level; i < BTREE_MAX_DEPTH; i++)
path->l[i].b = NULL;
return 1;
}
lock_type = __btree_lock_want(path, path->level);
if (unlikely(!btree_node_lock(trans, path, b, SPOS_MAX,
path->level, lock_type,
lock_root_check_fn, rootp,
trace_ip))) {
if (trans->restarted)
return -EINTR;
continue;
}
if (likely(b == READ_ONCE(*rootp) &&
b->c.level == path->level &&
!race_fault())) {
for (i = 0; i < path->level; i++)
path->l[i].b = BTREE_ITER_NO_NODE_LOCK_ROOT;
path->l[path->level].b = b;
for (i = path->level + 1; i < BTREE_MAX_DEPTH; i++)
path->l[i].b = NULL;
mark_btree_node_locked(path, path->level, lock_type);
btree_path_level_init(trans, path, b);
return 0;
}
six_unlock_type(&b->c.lock, lock_type);
}
}
noinline
static int btree_path_prefetch(struct btree_trans *trans, struct btree_path *path)
{
struct bch_fs *c = trans->c;
struct btree_path_level *l = path_l(path);
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)
? (path->level > 1 ? 0 : 2)
: (path->level > 1 ? 1 : 16);
bool was_locked = btree_node_locked(path, path->level);
int ret = 0;
bch2_bkey_buf_init(&tmp);
while (nr && !ret) {
if (!bch2_btree_node_relock(trans, path, path->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);
ret = bch2_btree_node_prefetch(c, trans, path, tmp.k, path->btree_id,
path->level - 1);
}
if (!was_locked)
btree_node_unlock(path, path->level);
bch2_bkey_buf_exit(&tmp, c);
return ret;
}
static int btree_path_prefetch_j(struct btree_trans *trans, struct btree_path *path,
struct btree_and_journal_iter *jiter)
{
struct bch_fs *c = trans->c;
struct bkey_s_c k;
struct bkey_buf tmp;
unsigned nr = test_bit(BCH_FS_STARTED, &c->flags)
? (path->level > 1 ? 0 : 2)
: (path->level > 1 ? 1 : 16);
bool was_locked = btree_node_locked(path, path->level);
int ret = 0;
bch2_bkey_buf_init(&tmp);
while (nr && !ret) {
if (!bch2_btree_node_relock(trans, path, path->level))
break;
bch2_btree_and_journal_iter_advance(jiter);
k = bch2_btree_and_journal_iter_peek(jiter);
if (!k.k)
break;
bch2_bkey_buf_reassemble(&tmp, c, k);
ret = bch2_btree_node_prefetch(c, trans, path, tmp.k, path->btree_id,
path->level - 1);
}
if (!was_locked)
btree_node_unlock(path, path->level);
bch2_bkey_buf_exit(&tmp, c);
return ret;
}
static noinline void btree_node_mem_ptr_set(struct btree_trans *trans,
struct btree_path *path,
unsigned plevel, struct btree *b)
{
struct btree_path_level *l = &path->l[plevel];
bool locked = btree_node_locked(path, plevel);
struct bkey_packed *k;
struct bch_btree_ptr_v2 *bp;
if (!bch2_btree_node_relock(trans, path, 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(path, plevel);
}
static noinline int btree_node_iter_and_journal_peek(struct btree_trans *trans,
struct btree_path *path,
unsigned flags,
struct bkey_buf *out)
{
struct bch_fs *c = trans->c;
struct btree_path_level *l = path_l(path);
struct btree_and_journal_iter jiter;
struct bkey_s_c k;
int ret = 0;
__bch2_btree_and_journal_iter_init_node_iter(&jiter, c, l->b, l->iter, path->pos);
k = bch2_btree_and_journal_iter_peek(&jiter);
bch2_bkey_buf_reassemble(out, c, k);
if (flags & BTREE_ITER_PREFETCH)
ret = btree_path_prefetch_j(trans, path, &jiter);
bch2_btree_and_journal_iter_exit(&jiter);
return ret;
}
static __always_inline int btree_path_down(struct btree_trans *trans,
struct btree_path *path,
unsigned flags,
unsigned long trace_ip)
{
struct bch_fs *c = trans->c;
struct btree_path_level *l = path_l(path);
struct btree *b;
unsigned level = path->level - 1;
enum six_lock_type lock_type = __btree_lock_want(path, level);
struct bkey_buf tmp;
int ret;
EBUG_ON(!btree_node_locked(path, path->level));
bch2_bkey_buf_init(&tmp);
if (unlikely(trans->journal_replay_not_finished)) {
ret = btree_node_iter_and_journal_peek(trans, path, flags, &tmp);
if (ret)
goto err;
} else {
bch2_bkey_buf_unpack(&tmp, c, l->b,
bch2_btree_node_iter_peek(&l->iter, l->b));
if (flags & BTREE_ITER_PREFETCH) {
ret = btree_path_prefetch(trans, path);
if (ret)
goto err;
}
}
b = bch2_btree_node_get(trans, path, tmp.k, level, lock_type, trace_ip);
ret = PTR_ERR_OR_ZERO(b);
if (unlikely(ret))
goto err;
mark_btree_node_locked(path, level, lock_type);
btree_path_level_init(trans, path, b);
if (likely(!trans->journal_replay_not_finished &&
tmp.k->k.type == KEY_TYPE_btree_ptr_v2) &&
unlikely(b != btree_node_mem_ptr(tmp.k)))
btree_node_mem_ptr_set(trans, path, level + 1, b);
if (btree_node_read_locked(path, level + 1))
btree_node_unlock(path, level + 1);
path->level = level;
bch2_btree_path_verify_locks(path);
err:
bch2_bkey_buf_exit(&tmp, c);
return ret;
}
static int btree_path_traverse_one(struct btree_trans *, struct btree_path *,
unsigned, unsigned long);
static int __btree_path_traverse_all(struct btree_trans *trans, int ret,
unsigned long trace_ip)
{
struct bch_fs *c = trans->c;
struct btree_path *path, *prev = NULL;
int i;
if (trans->in_traverse_all)
return -EINTR;
trans->in_traverse_all = true;
retry_all:
trans->restarted = false;
trans_for_each_path(trans, path)
path->should_be_locked = false;
btree_trans_sort_paths(trans);
trans_for_each_path_inorder_reverse(trans, path, i) {
if (prev) {
if (path->btree_id == prev->btree_id &&
path->locks_want < prev->locks_want)
__bch2_btree_path_upgrade(trans, path, prev->locks_want);
else if (!path->locks_want && prev->locks_want)
__bch2_btree_path_upgrade(trans, path, 1);
}
prev = path;
}
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))
goto out;
BUG_ON(ret && ret != -EINTR);
/* Now, redo traversals in correct order: */
i = 0;
while (i < trans->nr_sorted) {
path = trans->paths + trans->sorted[i];
/*
* Traversing a path can cause another path to be added at about
* the same position:
*/
if (path->uptodate) {
ret = btree_path_traverse_one(trans, path, 0, _THIS_IP_);
if (ret)
goto retry_all;
} else {
i++;
}
}
/*
* BTREE_ITER_NEED_RELOCK is ok here - if we called bch2_trans_unlock()
* and relock(), relock() won't relock since path->should_be_locked
* isn't set yet, which is all fine
*/
trans_for_each_path(trans, path)
BUG_ON(path->uptodate >= BTREE_ITER_NEED_TRAVERSE);
out:
bch2_btree_cache_cannibalize_unlock(c);
trans->in_traverse_all = false;
trace_trans_traverse_all(trans->fn, trace_ip);
return ret;
}
static int bch2_btree_path_traverse_all(struct btree_trans *trans)
{
return __btree_path_traverse_all(trans, 0, _RET_IP_);
}
static inline bool btree_path_good_node(struct btree_trans *trans,
struct btree_path *path,
unsigned l, int check_pos)
{
if (!is_btree_node(path, l) ||
!bch2_btree_node_relock(trans, path, l))
return false;
if (check_pos < 0 && btree_path_pos_before_node(path, path->l[l].b))
return false;
if (check_pos > 0 && btree_path_pos_after_node(path, path->l[l].b))
return false;
return true;
}
static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,
struct btree_path *path,
int check_pos)
{
unsigned i, l = path->level;
while (btree_path_node(path, l) &&
!btree_path_good_node(trans, path, l, check_pos)) {
btree_node_unlock(path, l);
path->l[l].b = BTREE_ITER_NO_NODE_UP;
l++;
}
/* If we need intent locks, take them too: */
for (i = l + 1;
i < path->locks_want && btree_path_node(path, i);
i++)
if (!bch2_btree_node_relock(trans, path, i))
while (l <= i) {
btree_node_unlock(path, l);
path->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_path_traverse_one(struct btree_trans *trans,
struct btree_path *path,
unsigned flags,
unsigned long trace_ip)
{
unsigned depth_want = path->level;
int ret = 0;
if (unlikely(trans->restarted)) {
ret = -EINTR;
goto out;
}
/*
* Ensure we obey path->should_be_locked: if it's set, we can't unlock
* and re-traverse the path without a transaction restart:
*/
if (path->should_be_locked) {
ret = bch2_btree_path_relock(trans, path, trace_ip) ? 0 : -EINTR;
goto out;
}
if (path->cached) {
ret = bch2_btree_path_traverse_cached(trans, path, flags);
goto out;
}
if (unlikely(path->level >= BTREE_MAX_DEPTH))
goto out;
path->level = btree_path_up_until_good_node(trans, path, 0);
/*
* Note: path->nodes[path->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_path_lock_root() comes next and that it can't fail
*/
while (path->level > depth_want) {
ret = btree_path_node(path, path->level)
? btree_path_down(trans, path, flags, trace_ip)
: btree_path_lock_root(trans, path, depth_want, trace_ip);
if (unlikely(ret)) {
if (ret == 1) {
/*
* No nodes at this level - got to the end of
* the btree:
*/
ret = 0;
goto out;
}
__bch2_btree_path_unlock(path);
path->level = depth_want;
if (ret == -EIO)
path->l[path->level].b =
BTREE_ITER_NO_NODE_ERROR;
else
path->l[path->level].b =
BTREE_ITER_NO_NODE_DOWN;
goto out;
}
}
path->uptodate = BTREE_ITER_UPTODATE;
out:
BUG_ON((ret == -EINTR) != !!trans->restarted);
bch2_btree_path_verify(trans, path);
return ret;
}
static int __btree_path_traverse_all(struct btree_trans *, int, unsigned long);
int __must_check bch2_btree_path_traverse(struct btree_trans *trans,
struct btree_path *path, unsigned flags)
{
if (path->uptodate < BTREE_ITER_NEED_RELOCK)
return 0;
return bch2_trans_cond_resched(trans) ?:
btree_path_traverse_one(trans, path, flags, _RET_IP_);
}
static void btree_path_copy(struct btree_trans *trans, struct btree_path *dst,
struct btree_path *src)
{
unsigned i, offset = offsetof(struct btree_path, pos);
memcpy((void *) dst + offset,
(void *) src + offset,
sizeof(struct btree_path) - offset);
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));
trans->paths_sorted = false;
}
static struct btree_path *btree_path_clone(struct btree_trans *trans, struct btree_path *src,
bool intent)
{
struct btree_path *new = btree_path_alloc(trans, src);
btree_path_copy(trans, new, src);
__btree_path_get(new, intent);
return new;
}
struct btree_path * __must_check
__bch2_btree_path_make_mut(struct btree_trans *trans,
struct btree_path *path, bool intent)
{
__btree_path_put(path, intent);
path = btree_path_clone(trans, path, intent);
path->preserve = false;
#ifdef CONFIG_BCACHEFS_DEBUG
path->ip_allocated = _RET_IP_;
#endif
return path;
}
struct btree_path * __must_check
__bch2_btree_path_set_pos(struct btree_trans *trans,
struct btree_path *path, struct bpos new_pos,
bool intent, int cmp)
{
unsigned l = path->level;
EBUG_ON(trans->restarted);
EBUG_ON(!path->ref);
path = bch2_btree_path_make_mut(trans, path, intent);
path->pos = new_pos;
path->should_be_locked = false;
trans->paths_sorted = false;
if (unlikely(path->cached)) {
btree_node_unlock(path, 0);
path->l[0].b = BTREE_ITER_NO_NODE_CACHED;
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
goto out;
}
l = btree_path_up_until_good_node(trans, path, cmp);
if (btree_path_node(path, 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_path_advance_to_pos(path, &path->l[l], 8))
__btree_path_level_init(path, l);
}
if (l != path->level) {
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
__bch2_btree_path_unlock(path);
}
out:
bch2_btree_path_verify(trans, path);
return path;
}
/* Btree path: main interface: */
static struct btree_path *have_path_at_pos(struct btree_trans *trans, struct btree_path *path)
{
struct btree_path *next;
next = prev_btree_path(trans, path);
if (next && !btree_path_cmp(next, path))
return next;
next = next_btree_path(trans, path);
if (next && !btree_path_cmp(next, path))
return next;
return NULL;
}
static struct btree_path *have_node_at_pos(struct btree_trans *trans, struct btree_path *path)
{
struct btree_path *next;
next = prev_btree_path(trans, path);
if (next && next->level == path->level && path_l(next)->b == path_l(path)->b)
return next;
next = next_btree_path(trans, path);
if (next && next->level == path->level && path_l(next)->b == path_l(path)->b)
return next;
return NULL;
}
static inline void __bch2_path_free(struct btree_trans *trans, struct btree_path *path)
{
__bch2_btree_path_unlock(path);
btree_path_list_remove(trans, path);
trans->paths_allocated &= ~(1ULL << path->idx);
}
void bch2_path_put(struct btree_trans *trans, struct btree_path *path, bool intent)
{
struct btree_path *dup;
EBUG_ON(trans->paths + path->idx != path);
EBUG_ON(!path->ref);
if (!__btree_path_put(path, intent))
return;
/*
* Perhaps instead we should check for duplicate paths in traverse_all:
*/
if (path->preserve &&
(dup = have_path_at_pos(trans, path))) {
dup->preserve = true;
path->preserve = false;
goto free;
}
if (!path->preserve &&
(dup = have_node_at_pos(trans, path)))
goto free;
return;
free:
if (path->should_be_locked &&
!btree_node_locked(dup, path->level))
return;
dup->should_be_locked |= path->should_be_locked;
__bch2_path_free(trans, path);
}
noinline __cold
void bch2_dump_trans_paths_updates(struct btree_trans *trans)
{
struct btree_path *path;
struct btree_insert_entry *i;
unsigned idx;
char buf1[300], buf2[300];
btree_trans_sort_paths(trans);
trans_for_each_path_inorder(trans, path, idx)
printk(KERN_ERR "path: idx %u ref %u:%u%s%s btree %s pos %s locks %u %pS\n",
path->idx, path->ref, path->intent_ref,
path->should_be_locked ? " S" : "",
path->preserve ? " P" : "",
bch2_btree_ids[path->btree_id],
(bch2_bpos_to_text(&PBUF(buf1), path->pos), buf1),
path->nodes_locked,
#ifdef CONFIG_BCACHEFS_DEBUG
(void *) path->ip_allocated
#else
NULL
#endif
);
trans_for_each_update(trans, i) {
struct bkey u;
struct bkey_s_c old = bch2_btree_path_peek_slot(i->path, &u);
printk(KERN_ERR "update: btree %s %pS\n old %s\n new %s",
bch2_btree_ids[i->btree_id],
(void *) i->ip_allocated,
(bch2_bkey_val_to_text(&PBUF(buf1), trans->c, old), buf1),
(bch2_bkey_val_to_text(&PBUF(buf2), trans->c, bkey_i_to_s_c(i->k)), buf2));
}
}
static struct btree_path *btree_path_alloc(struct btree_trans *trans,
struct btree_path *pos)
{
struct btree_path *path;
unsigned idx;
if (unlikely(trans->paths_allocated ==
~((~0ULL << 1) << (BTREE_ITER_MAX - 1)))) {
bch2_dump_trans_paths_updates(trans);
panic("trans path oveflow\n");
}
idx = __ffs64(~trans->paths_allocated);
trans->paths_allocated |= 1ULL << idx;
path = &trans->paths[idx];
path->idx = idx;
path->ref = 0;
path->intent_ref = 0;
path->nodes_locked = 0;
path->nodes_intent_locked = 0;
btree_path_list_add(trans, pos, path);
return path;
}
struct btree_path *bch2_path_get(struct btree_trans *trans,
enum btree_id btree_id, struct bpos pos,
unsigned locks_want, unsigned level,
unsigned flags)
{
struct btree_path *path, *path_pos = NULL;
bool cached = flags & BTREE_ITER_CACHED;
bool intent = flags & BTREE_ITER_INTENT;
int i;
BUG_ON(trans->restarted);
btree_trans_sort_paths(trans);
trans_for_each_path_inorder(trans, path, i) {
if (__btree_path_cmp(path,
btree_id,
cached,
pos,
level) > 0)
break;
path_pos = path;
}
if (path_pos &&
path_pos->cached == cached &&
path_pos->btree_id == btree_id &&
path_pos->level == level) {
__btree_path_get(path_pos, intent);
path = bch2_btree_path_set_pos(trans, path_pos, pos, intent);
} else {
path = btree_path_alloc(trans, path_pos);
path_pos = NULL;
__btree_path_get(path, intent);
path->pos = pos;
path->btree_id = btree_id;
path->cached = cached;
path->uptodate = BTREE_ITER_NEED_TRAVERSE;
path->should_be_locked = false;
path->level = level;
path->locks_want = locks_want;
path->nodes_locked = 0;
path->nodes_intent_locked = 0;
for (i = 0; i < ARRAY_SIZE(path->l); i++)
path->l[i].b = BTREE_ITER_NO_NODE_INIT;
#ifdef CONFIG_BCACHEFS_DEBUG
path->ip_allocated = _RET_IP_;
#endif
trans->paths_sorted = false;
}
if (!(flags & BTREE_ITER_NOPRESERVE))
path->preserve = true;
if (path->intent_ref)
locks_want = max(locks_want, level + 1);
/*
* If the path has locks_want greater than requested, we don't 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 bch2_trans_downgrade(), after
* a successful transaction commit.
*/
locks_want = min(locks_want, BTREE_MAX_DEPTH);
if (locks_want > path->locks_want) {
path->locks_want = locks_want;
btree_path_get_locks(trans, path, true);
}
return path;
}
inline struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *path, struct bkey *u)
{
struct bkey_s_c k;
if (!path->cached) {
struct btree_path_level *l = path_l(path);
struct bkey_packed *_k;
EBUG_ON(path->uptodate != BTREE_ITER_UPTODATE);
_k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
k = _k ? bkey_disassemble(l->b, _k, u) : bkey_s_c_null;
EBUG_ON(k.k && bkey_deleted(k.k) && bpos_cmp(k.k->p, path->pos) == 0);
if (!k.k || bpos_cmp(path->pos, k.k->p))
goto hole;
} else {
struct bkey_cached *ck = (void *) path->l[0].b;
EBUG_ON(ck &&
(path->btree_id != ck->key.btree_id ||
bkey_cmp(path->pos, ck->key.pos)));
/* BTREE_ITER_CACHED_NOFILL|BTREE_ITER_CACHED_NOCREATE? */
if (unlikely(!ck || !ck->valid))
return bkey_s_c_null;
EBUG_ON(path->uptodate != BTREE_ITER_UPTODATE);
*u = ck->k->k;
k = bkey_i_to_s_c(ck->k);
}
return k;
hole:
bkey_init(u);
u->p = path->pos;
return (struct bkey_s_c) { u, NULL };
}
/* Btree iterators: */
int __must_check
__bch2_btree_iter_traverse(struct btree_iter *iter)
{
return bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);
}
int __must_check
bch2_btree_iter_traverse(struct btree_iter *iter)
{
int ret;
iter->path = bch2_btree_path_set_pos(iter->trans, iter->path,
btree_iter_search_key(iter),
iter->flags & BTREE_ITER_INTENT);
ret = bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);
if (ret)
return ret;
iter->path->should_be_locked = true;
return 0;
}
/* Iterate across nodes (leaf and interior nodes) */
struct btree *bch2_btree_iter_peek_node(struct btree_iter *iter)
{
struct btree_trans *trans = iter->trans;
struct btree *b = NULL;
int ret;
EBUG_ON(iter->path->cached);
bch2_btree_iter_verify(iter);
ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
if (ret)
goto err;
b = btree_path_node(iter->path, iter->path->level);
if (!b)
goto out;
BUG_ON(bpos_cmp(b->key.k.p, iter->pos) < 0);
bkey_init(&iter->k);
iter->k.p = iter->pos = b->key.k.p;
iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,
iter->flags & BTREE_ITER_INTENT);
iter->path->should_be_locked = true;
BUG_ON(iter->path->uptodate);
out:
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
return b;
err:
b = ERR_PTR(ret);
goto out;
}
struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
{
struct btree_trans *trans = iter->trans;
struct btree_path *path = iter->path;
struct btree *b = NULL;
unsigned l;
int ret;
BUG_ON(trans->restarted);
EBUG_ON(iter->path->cached);
bch2_btree_iter_verify(iter);
/* already at end? */
if (!btree_path_node(path, path->level))
return NULL;
/* got to end? */
if (!btree_path_node(path, path->level + 1)) {
btree_node_unlock(path, path->level);
path->l[path->level].b = BTREE_ITER_NO_NODE_UP;
path->level++;
return NULL;
}
if (!bch2_btree_node_relock(trans, path, path->level + 1)) {
__bch2_btree_path_unlock(path);
path->l[path->level].b = BTREE_ITER_NO_NODE_GET_LOCKS;
path->l[path->level + 1].b = BTREE_ITER_NO_NODE_GET_LOCKS;
trace_trans_restart_relock_next_node(trans->fn, _THIS_IP_,
path->btree_id, &path->pos);
btree_trans_restart(trans);
ret = -EINTR;
goto err;
}
b = btree_path_node(path, path->level + 1);
if (!bpos_cmp(iter->pos, b->key.k.p)) {
btree_node_unlock(path, path->level);
path->l[path->level].b = BTREE_ITER_NO_NODE_UP;
path->level++;
} else {
/*
* Haven't gotten to the end of the parent node: go back down to
* the next child node
*/
path = iter->path =
bch2_btree_path_set_pos(trans, path, bpos_successor(iter->pos),
iter->flags & BTREE_ITER_INTENT);
path->level = iter->min_depth;
for (l = path->level + 1; l < BTREE_MAX_DEPTH; l++)
if (btree_lock_want(path, l) == BTREE_NODE_UNLOCKED)
btree_node_unlock(path, l);
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
bch2_btree_iter_verify(iter);
ret = bch2_btree_path_traverse(trans, path, iter->flags);
if (ret)
goto err;
b = path->l[path->level].b;
}
bkey_init(&iter->k);
iter->k.p = iter->pos = b->key.k.p;
iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,
iter->flags & BTREE_ITER_INTENT);
iter->path->should_be_locked = true;
BUG_ON(iter->path->uptodate);
out:
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
return b;
err:
b = ERR_PTR(ret);
goto out;
}
/* Iterate across keys (in leaf nodes only) */
inline bool bch2_btree_iter_advance(struct btree_iter *iter)
{
struct bpos pos = iter->k.p;
bool ret = (iter->flags & BTREE_ITER_ALL_SNAPSHOTS
? bpos_cmp(pos, SPOS_MAX)
: bkey_cmp(pos, SPOS_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 = (iter->flags & BTREE_ITER_ALL_SNAPSHOTS
? bpos_cmp(pos, POS_MIN)
: bkey_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 noinline
struct bkey_i *__bch2_btree_trans_peek_updates(struct btree_iter *iter)
{
struct btree_insert_entry *i;
struct bkey_i *ret = NULL;
trans_for_each_update(iter->trans, i) {
if (i->btree_id < iter->btree_id)
continue;
if (i->btree_id > iter->btree_id)
break;
if (bpos_cmp(i->k->k.p, iter->path->pos) < 0)
continue;
if (i->key_cache_already_flushed)
continue;
if (!ret || bpos_cmp(i->k->k.p, ret->k.p) < 0)
ret = i->k;
}
return ret;
}
static inline struct bkey_i *btree_trans_peek_updates(struct btree_iter *iter)
{
return iter->flags & BTREE_ITER_WITH_UPDATES
? __bch2_btree_trans_peek_updates(iter)
: NULL;
}
static noinline
struct bkey_s_c btree_trans_peek_slot_journal(struct btree_trans *trans,
struct btree_iter *iter)
{
struct bkey_i *k = bch2_journal_keys_peek(trans->c, iter->btree_id, 0,
iter->path->pos);
if (k && !bpos_cmp(k->k.p, iter->path->pos)) {
iter->k = k->k;
return bkey_i_to_s_c(k);
} else {
return bkey_s_c_null;
}
}
static noinline
struct bkey_s_c btree_trans_peek_journal(struct btree_trans *trans,
struct btree_iter *iter,
struct bkey_s_c k)
{
struct bkey_i *next_journal =
bch2_journal_keys_peek(trans->c, iter->btree_id, 0,
iter->path->pos);
if (next_journal &&
bpos_cmp(next_journal->k.p,
k.k ? k.k->p : iter->path->l[0].b->key.k.p) <= 0) {
iter->k = next_journal->k;
k = bkey_i_to_s_c(next_journal);
}
return k;
}
/*
* Checks btree key cache for key at iter->pos and returns it if present, or
* bkey_s_c_null:
*/
static noinline
struct bkey_s_c btree_trans_peek_key_cache(struct btree_iter *iter, struct bpos pos)
{
struct btree_trans *trans = iter->trans;
struct bch_fs *c = trans->c;
struct bkey u;
int ret;
if (!bch2_btree_key_cache_find(c, iter->btree_id, pos))
return bkey_s_c_null;
if (!iter->key_cache_path)
iter->key_cache_path = bch2_path_get(trans, iter->btree_id, pos,
iter->flags & BTREE_ITER_INTENT, 0,
iter->flags|BTREE_ITER_CACHED);
iter->key_cache_path = bch2_btree_path_set_pos(trans, iter->key_cache_path, pos,
iter->flags & BTREE_ITER_INTENT);
ret = bch2_btree_path_traverse(trans, iter->key_cache_path, iter->flags|BTREE_ITER_CACHED);
if (unlikely(ret))
return bkey_s_c_err(ret);
iter->key_cache_path->should_be_locked = true;
return bch2_btree_path_peek_slot(iter->key_cache_path, &u);
}
static struct bkey_s_c __bch2_btree_iter_peek(struct btree_iter *iter, struct bpos search_key)
{
struct btree_trans *trans = iter->trans;
struct bkey_i *next_update;
struct bkey_s_c k, k2;
int ret;
EBUG_ON(iter->path->cached || iter->path->level);
bch2_btree_iter_verify(iter);
while (1) {
iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
iter->flags & BTREE_ITER_INTENT);
ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
if (unlikely(ret)) {
/* ensure that iter->k is consistent with iter->pos: */
bch2_btree_iter_set_pos(iter, iter->pos);
k = bkey_s_c_err(ret);
goto out;
}
iter->path->should_be_locked = true;
k = btree_path_level_peek_all(trans->c, &iter->path->l[0], &iter->k);
if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
k.k &&
(k2 = btree_trans_peek_key_cache(iter, k.k->p)).k) {
ret = bkey_err(k2);
if (ret) {
k = k2;
bch2_btree_iter_set_pos(iter, iter->pos);
goto out;
}
k = k2;
iter->k = *k.k;
}
if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL))
k = btree_trans_peek_journal(trans, iter, k);
next_update = btree_trans_peek_updates(iter);
if (next_update &&
bpos_cmp(next_update->k.p,
k.k ? k.k->p : iter->path->l[0].b->key.k.p) <= 0) {
iter->k = next_update->k;
k = bkey_i_to_s_c(next_update);
}
if (k.k && bkey_deleted(k.k)) {
/*
* If we've got a whiteout, and it's after the search
* key, advance the search key to the whiteout instead
* of just after the whiteout - it might be a btree
* whiteout, with a real key at the same position, since
* in the btree deleted keys sort before non deleted.
*/
search_key = bpos_cmp(search_key, k.k->p)
? k.k->p
: bpos_successor(k.k->p);
continue;
}
if (likely(k.k)) {
break;
} else if (likely(bpos_cmp(iter->path->l[0].b->key.k.p, SPOS_MAX))) {
/* Advance to next leaf node: */
search_key = bpos_successor(iter->path->l[0].b->key.k.p);
} else {
/* End of btree: */
bch2_btree_iter_set_pos(iter, SPOS_MAX);
k = bkey_s_c_null;
goto out;
}
}
out:
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)
{
struct btree_trans *trans = iter->trans;
struct bpos search_key = btree_iter_search_key(iter);
struct bkey_s_c k;
int ret;
if (iter->update_path) {
bch2_path_put(trans, iter->update_path,
iter->flags & BTREE_ITER_INTENT);
iter->update_path = NULL;
}
bch2_btree_iter_verify_entry_exit(iter);
while (1) {
k = __bch2_btree_iter_peek(iter, search_key);
if (!k.k || bkey_err(k))
goto out;
if (iter->update_path &&
bkey_cmp(iter->update_path->pos, k.k->p)) {
bch2_path_put(trans, iter->update_path,
iter->flags & BTREE_ITER_INTENT);
iter->update_path = NULL;
}
if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
(iter->flags & BTREE_ITER_INTENT) &&
!(iter->flags & BTREE_ITER_IS_EXTENTS) &&
!iter->update_path) {
struct bpos pos = k.k->p;
if (pos.snapshot < iter->snapshot) {
search_key = bpos_successor(k.k->p);
continue;
}
pos.snapshot = iter->snapshot;
/*
* advance, same as on exit for iter->path, but only up
* to snapshot
*/
__btree_path_get(iter->path, iter->flags & BTREE_ITER_INTENT);
iter->update_path = iter->path;
iter->update_path = bch2_btree_path_set_pos(trans,
iter->update_path, pos,
iter->flags & BTREE_ITER_INTENT);
BUG_ON(!(iter->update_path->nodes_locked & 1));
iter->update_path->should_be_locked = true;
}
/*
* We can never have a key in a leaf node at POS_MAX, so
* we don't have to check these successor() calls:
*/
if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
!bch2_snapshot_is_ancestor(trans->c,
iter->snapshot,
k.k->p.snapshot)) {
search_key = bpos_successor(k.k->p);
continue;
}
if (bkey_whiteout(k.k) &&
!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
search_key = bkey_successor(iter, k.k->p);
continue;
}
break;
}
/*
* 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);
iter->path = bch2_btree_path_set_pos(trans, iter->path, k.k->p,
iter->flags & BTREE_ITER_INTENT);
BUG_ON(!iter->path->nodes_locked);
out:
if (iter->update_path) {
BUG_ON(!(iter->update_path->nodes_locked & 1));
iter->update_path->should_be_locked = true;
}
iter->path->should_be_locked = true;
if (!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS))
iter->pos.snapshot = iter->snapshot;
ret = bch2_btree_iter_verify_ret(iter, k);
if (unlikely(ret)) {
bch2_btree_iter_set_pos(iter, iter->pos);
k = bkey_s_c_err(ret);
}
bch2_btree_iter_verify_entry_exit(iter);
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 (!bch2_btree_iter_advance(iter))
return bkey_s_c_null;
return bch2_btree_iter_peek(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_trans *trans = iter->trans;
struct bpos search_key = iter->pos;
struct btree_path *saved_path = NULL;
struct bkey_s_c k;
struct bkey saved_k;
const struct bch_val *saved_v;
int ret;
EBUG_ON(iter->path->cached || iter->path->level);
EBUG_ON(iter->flags & BTREE_ITER_WITH_UPDATES);
if (iter->flags & BTREE_ITER_WITH_JOURNAL)
return bkey_s_c_err(-EIO);
bch2_btree_iter_verify(iter);
bch2_btree_iter_verify_entry_exit(iter);
if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
search_key.snapshot = U32_MAX;
while (1) {
iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
iter->flags & BTREE_ITER_INTENT);
ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
if (unlikely(ret)) {
/* ensure that iter->k is consistent with iter->pos: */
bch2_btree_iter_set_pos(iter, iter->pos);
k = bkey_s_c_err(ret);
goto out;
}
k = btree_path_level_peek(trans, iter->path,
&iter->path->l[0], &iter->k);
if (!k.k ||
((iter->flags & BTREE_ITER_IS_EXTENTS)
? bpos_cmp(bkey_start_pos(k.k), search_key) >= 0
: bpos_cmp(k.k->p, search_key) > 0))
k = btree_path_level_prev(trans, iter->path,
&iter->path->l[0], &iter->k);
if (likely(k.k)) {
if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) {
if (k.k->p.snapshot == iter->snapshot)
goto got_key;
/*
* If we have a saved candidate, and we're no
* longer at the same _key_ (not pos), return
* that candidate
*/
if (saved_path && bkey_cmp(k.k->p, saved_k.p)) {
bch2_path_put(trans, iter->path,
iter->flags & BTREE_ITER_INTENT);
iter->path = saved_path;
saved_path = NULL;
iter->k = saved_k;
k.v = saved_v;
goto got_key;
}
if (bch2_snapshot_is_ancestor(iter->trans->c,
iter->snapshot,
k.k->p.snapshot)) {
if (saved_path)
bch2_path_put(trans, saved_path,
iter->flags & BTREE_ITER_INTENT);
saved_path = btree_path_clone(trans, iter->path,
iter->flags & BTREE_ITER_INTENT);
saved_k = *k.k;
saved_v = k.v;
}
search_key = bpos_predecessor(k.k->p);
continue;
}
got_key:
if (bkey_whiteout(k.k) &&
!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
search_key = bkey_predecessor(iter, k.k->p);
if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
search_key.snapshot = U32_MAX;
continue;
}
break;
} else if (likely(bpos_cmp(iter->path->l[0].b->data->min_key, POS_MIN))) {
/* Advance to previous leaf node: */
search_key = bpos_predecessor(iter->path->l[0].b->data->min_key);
} else {
/* Start of btree: */
bch2_btree_iter_set_pos(iter, POS_MIN);
k = bkey_s_c_null;
goto out;
}
}
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;
if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
iter->pos.snapshot = iter->snapshot;
out:
if (saved_path)
bch2_path_put(trans, saved_path, iter->flags & BTREE_ITER_INTENT);
iter->path->should_be_locked = true;
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
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)
{
if (!bch2_btree_iter_rewind(iter))
return bkey_s_c_null;
return bch2_btree_iter_peek_prev(iter);
}
struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)
{
struct btree_trans *trans = iter->trans;
struct bpos search_key;
struct bkey_s_c k;
int ret;
EBUG_ON(iter->path->level);
bch2_btree_iter_verify(iter);
bch2_btree_iter_verify_entry_exit(iter);
/* extents can't span inode numbers: */
if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
unlikely(iter->pos.offset == KEY_OFFSET_MAX)) {
if (iter->pos.inode == KEY_INODE_MAX)
return bkey_s_c_null;
bch2_btree_iter_set_pos(iter, bpos_nosnap_successor(iter->pos));
}
search_key = btree_iter_search_key(iter);
iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
iter->flags & BTREE_ITER_INTENT);
ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
if (unlikely(ret))
return bkey_s_c_err(ret);
if ((iter->flags & BTREE_ITER_CACHED) ||
!(iter->flags & (BTREE_ITER_IS_EXTENTS|BTREE_ITER_FILTER_SNAPSHOTS))) {
struct bkey_i *next_update;
if ((next_update = btree_trans_peek_updates(iter)) &&
!bpos_cmp(next_update->k.p, iter->pos)) {
iter->k = next_update->k;
k = bkey_i_to_s_c(next_update);
goto out;
}
if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL) &&
(k = btree_trans_peek_slot_journal(trans, iter)).k)
goto out;
if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
(k = btree_trans_peek_key_cache(iter, iter->pos)).k) {
if (!bkey_err(k))
iter->k = *k.k;
goto out;
}
k = bch2_btree_path_peek_slot(iter->path, &iter->k);
} else {
struct bpos next;
if (iter->flags & BTREE_ITER_INTENT) {
struct btree_iter iter2;
bch2_trans_copy_iter(&iter2, iter);
k = bch2_btree_iter_peek(&iter2);
if (k.k && !bkey_err(k)) {
iter->k = iter2.k;
k.k = &iter->k;
}
bch2_trans_iter_exit(trans, &iter2);
} else {
struct bpos pos = iter->pos;
k = bch2_btree_iter_peek(iter);
iter->pos = pos;
}
if (unlikely(bkey_err(k)))
return k;
next = k.k ? bkey_start_pos(k.k) : POS_MAX;
if (bkey_cmp(iter->pos, next) < 0) {
bkey_init(&iter->k);
iter->k.p = iter->pos;
if (iter->flags & BTREE_ITER_IS_EXTENTS) {
bch2_key_resize(&iter->k,
min_t(u64, KEY_SIZE_MAX,
(next.inode == iter->pos.inode
? next.offset
: KEY_OFFSET_MAX) -
iter->pos.offset));
EBUG_ON(!iter->k.size);
}
k = (struct bkey_s_c) { &iter->k, NULL };
}
}
out:
iter->path->should_be_locked = true;
bch2_btree_iter_verify_entry_exit(iter);
bch2_btree_iter_verify(iter);
ret = bch2_btree_iter_verify_ret(iter, k);
if (unlikely(ret))
return bkey_s_c_err(ret);
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);
}
/* new transactional stuff: */
#ifdef CONFIG_BCACHEFS_DEBUG
static void btree_trans_verify_sorted_refs(struct btree_trans *trans)
{
struct btree_path *path;
unsigned i;
BUG_ON(trans->nr_sorted != hweight64(trans->paths_allocated));
trans_for_each_path(trans, path) {
BUG_ON(path->sorted_idx >= trans->nr_sorted);
BUG_ON(trans->sorted[path->sorted_idx] != path->idx);
}
for (i = 0; i < trans->nr_sorted; i++) {
unsigned idx = trans->sorted[i];
EBUG_ON(!(trans->paths_allocated & (1ULL << idx)));
BUG_ON(trans->paths[idx].sorted_idx != i);
}
}
static void btree_trans_verify_sorted(struct btree_trans *trans)
{
struct btree_path *path, *prev = NULL;
unsigned i;
trans_for_each_path_inorder(trans, path, i) {
BUG_ON(prev && btree_path_cmp(prev, path) > 0);
prev = path;
}
}
#else
static inline void btree_trans_verify_sorted_refs(struct btree_trans *trans) {}
static inline void btree_trans_verify_sorted(struct btree_trans *trans) {}
#endif
void __bch2_btree_trans_sort_paths(struct btree_trans *trans)
{
int i, l = 0, r = trans->nr_sorted, inc = 1;
bool swapped;
btree_trans_verify_sorted_refs(trans);
if (trans->paths_sorted)
goto out;
/*
* Cocktail shaker sort: this is efficient because iterators will be
* mostly sorteda.
*/
do {
swapped = false;
for (i = inc > 0 ? l : r - 2;
i + 1 < r && i >= l;
i += inc) {
if (btree_path_cmp(trans->paths + trans->sorted[i],
trans->paths + trans->sorted[i + 1]) > 0) {
swap(trans->sorted[i], trans->sorted[i + 1]);
trans->paths[trans->sorted[i]].sorted_idx = i;
trans->paths[trans->sorted[i + 1]].sorted_idx = i + 1;
swapped = true;
}
}
if (inc > 0)
--r;
else
l++;
inc = -inc;
} while (swapped);
trans->paths_sorted = true;
out:
btree_trans_verify_sorted(trans);
}
static inline void btree_path_list_remove(struct btree_trans *trans,
struct btree_path *path)
{
unsigned i;
EBUG_ON(path->sorted_idx >= trans->nr_sorted);
#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
trans->nr_sorted--;
memmove_u64s_down_small(trans->sorted + path->sorted_idx,
trans->sorted + path->sorted_idx + 1,
DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx, 8));
#else
array_remove_item(trans->sorted, trans->nr_sorted, path->sorted_idx);
#endif
for (i = path->sorted_idx; i < trans->nr_sorted; i++)
trans->paths[trans->sorted[i]].sorted_idx = i;
path->sorted_idx = U8_MAX;
}
static inline void btree_path_list_add(struct btree_trans *trans,
struct btree_path *pos,
struct btree_path *path)
{
unsigned i;
path->sorted_idx = pos ? pos->sorted_idx + 1 : trans->nr_sorted;
#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
memmove_u64s_up_small(trans->sorted + path->sorted_idx + 1,
trans->sorted + path->sorted_idx,
DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx, 8));
trans->nr_sorted++;
trans->sorted[path->sorted_idx] = path->idx;
#else
array_insert_item(trans->sorted, trans->nr_sorted, path->sorted_idx, path->idx);
#endif
for (i = path->sorted_idx; i < trans->nr_sorted; i++)
trans->paths[trans->sorted[i]].sorted_idx = i;
btree_trans_verify_sorted_refs(trans);
}
void bch2_trans_iter_exit(struct btree_trans *trans, struct btree_iter *iter)
{
if (iter->path)
bch2_path_put(trans, iter->path,
iter->flags & BTREE_ITER_INTENT);
if (iter->update_path)
bch2_path_put(trans, iter->update_path,
iter->flags & BTREE_ITER_INTENT);
if (iter->key_cache_path)
bch2_path_put(trans, iter->key_cache_path,
iter->flags & BTREE_ITER_INTENT);
iter->path = NULL;
iter->update_path = NULL;
iter->key_cache_path = NULL;
}
static void __bch2_trans_iter_init(struct btree_trans *trans,
struct btree_iter *iter,
enum btree_id btree_id, struct bpos pos,
unsigned locks_want,
unsigned depth,
unsigned flags)
{
EBUG_ON(trans->restarted);
if (!(flags & (BTREE_ITER_ALL_SNAPSHOTS|BTREE_ITER_NOT_EXTENTS)) &&
btree_node_type_is_extents(btree_id))
flags |= BTREE_ITER_IS_EXTENTS;
if (!(flags & __BTREE_ITER_ALL_SNAPSHOTS) &&
!btree_type_has_snapshots(btree_id))
flags &= ~BTREE_ITER_ALL_SNAPSHOTS;
if (!(flags & BTREE_ITER_ALL_SNAPSHOTS) &&
btree_type_has_snapshots(btree_id))
flags |= BTREE_ITER_FILTER_SNAPSHOTS;
if (trans->journal_replay_not_finished)
flags |= BTREE_ITER_WITH_JOURNAL;
if (!btree_id_cached(trans->c, btree_id)) {
flags &= ~BTREE_ITER_CACHED;
flags &= ~BTREE_ITER_WITH_KEY_CACHE;
} else if (!(flags & BTREE_ITER_CACHED))
flags |= BTREE_ITER_WITH_KEY_CACHE;
iter->trans = trans;
iter->path = NULL;
iter->update_path = NULL;
iter->key_cache_path = NULL;
iter->btree_id = btree_id;
iter->min_depth = depth;
iter->flags = flags;
iter->snapshot = pos.snapshot;
iter->pos = pos;
iter->k.type = KEY_TYPE_deleted;
iter->k.p = pos;
iter->k.size = 0;
iter->path = bch2_path_get(trans, btree_id, iter->pos,
locks_want, depth, flags);
}
void bch2_trans_iter_init(struct btree_trans *trans,
struct btree_iter *iter,
unsigned btree_id, struct bpos pos,
unsigned flags)
{
__bch2_trans_iter_init(trans, iter, btree_id, pos,
0, 0, flags);
}
void bch2_trans_node_iter_init(struct btree_trans *trans,
struct btree_iter *iter,
enum btree_id btree_id,
struct bpos pos,
unsigned locks_want,
unsigned depth,
unsigned flags)
{
__bch2_trans_iter_init(trans, iter, btree_id, pos, locks_want, depth,
BTREE_ITER_NOT_EXTENTS|
__BTREE_ITER_ALL_SNAPSHOTS|
BTREE_ITER_ALL_SNAPSHOTS|
flags);
BUG_ON(iter->path->locks_want < min(locks_want, BTREE_MAX_DEPTH));
BUG_ON(iter->path->level != depth);
BUG_ON(iter->min_depth != depth);
}
void bch2_trans_copy_iter(struct btree_iter *dst, struct btree_iter *src)
{
*dst = *src;
if (src->path)
__btree_path_get(src->path, src->flags & BTREE_ITER_INTENT);
if (src->update_path)
__btree_path_get(src->update_path, src->flags & BTREE_ITER_INTENT);
dst->key_cache_path = NULL;
}
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->fn, _RET_IP_, new_bytes);
btree_trans_restart(trans);
return ERR_PTR(-EINTR);
}
}
p = trans->mem + trans->mem_top;
trans->mem_top += size;
memset(p, 0, size);
return p;
}
/**
* bch2_trans_begin() - reset a transaction after a interrupted attempt
* @trans: transaction to reset
*
* While iterating over nodes or updating nodes a attempt to lock a btree
* node may return EINTR when the trylock fails. When this occurs
* bch2_trans_begin() should be called and the transaction retried.
*/
void bch2_trans_begin(struct btree_trans *trans)
{
struct btree_insert_entry *i;
struct btree_path *path;
trans_for_each_update(trans, i)
__btree_path_put(i->path, true);
memset(&trans->journal_res, 0, sizeof(trans->journal_res));
trans->extra_journal_res = 0;
trans->nr_updates = 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);
}
trans_for_each_path(trans, path) {
/*
* XXX: we probably shouldn't be doing this if the transaction
* was restarted, but currently we still overflow transaction
* iterators if we do that
*/
if (!path->ref && !path->preserve)
__bch2_path_free(trans, path);
else
path->preserve = path->should_be_locked = false;
}
bch2_trans_cond_resched(trans);
if (trans->restarted)
bch2_btree_path_traverse_all(trans);
trans->restarted = false;
}
static void bch2_trans_alloc_paths(struct btree_trans *trans, struct bch_fs *c)
{
size_t paths_bytes = sizeof(struct btree_path) * 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_paths_bufs->path , NULL);
#endif
if (!p)
p = mempool_alloc(&trans->c->btree_paths_pool, GFP_NOFS);
trans->paths = p; p += paths_bytes;
trans->updates = 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,
const char *fn)
__acquires(&c->btree_trans_barrier)
{
memset(trans, 0, sizeof(*trans));
trans->c = c;
trans->fn = fn;
trans->journal_replay_not_finished =
!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags);
bch2_trans_alloc_paths(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);
if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
trans->pid = current->pid;
mutex_lock(&c->btree_trans_lock);
list_add(&trans->list, &c->btree_trans_list);
mutex_unlock(&c->btree_trans_lock);
}
}
static void check_btree_paths_leaked(struct btree_trans *trans)
{
#ifdef CONFIG_BCACHEFS_DEBUG
struct bch_fs *c = trans->c;
struct btree_path *path;
trans_for_each_path(trans, path)
if (path->ref)
goto leaked;
return;
leaked:
bch_err(c, "btree paths leaked from %s!", trans->fn);
trans_for_each_path(trans, path)
if (path->ref)
printk(KERN_ERR " btree %s %pS\n",
bch2_btree_ids[path->btree_id],
(void *) path->ip_allocated);
/* Be noisy about this: */
bch2_fatal_error(c);
#endif
}
void bch2_trans_exit(struct btree_trans *trans)
__releases(&c->btree_trans_barrier)
{
struct btree_insert_entry *i;
struct bch_fs *c = trans->c;
bch2_trans_unlock(trans);
trans_for_each_update(trans, i)
__btree_path_put(i->path, true);
trans->nr_updates = 0;
check_btree_paths_leaked(trans);
if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
mutex_lock(&c->btree_trans_lock);
list_del(&trans->list);
mutex_unlock(&c->btree_trans_lock);
}
srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
bch2_journal_preres_put(&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,
&c->replicas_delta_pool);
else
kfree(trans->fs_usage_deltas);
}
if (trans->mem_bytes == BTREE_TRANS_MEM_MAX)
mempool_free(trans->mem, &c->btree_trans_mem_pool);
else
kfree(trans->mem);
#ifdef __KERNEL__
/*
* Userspace doesn't have a real percpu implementation:
*/
trans->paths = this_cpu_xchg(c->btree_paths_bufs->path, trans->paths);
#endif
if (trans->paths)
mempool_free(trans->paths, &c->btree_paths_pool);
trans->mem = (void *) 0x1;
trans->paths = (void *) 0x1;
}
static void __maybe_unused
bch2_btree_path_node_to_text(struct printbuf *out,
struct btree_bkey_cached_common *_b,
bool cached)
{
pr_buf(out, " l=%u %s:",
_b->level, bch2_btree_ids[_b->btree_id]);
bch2_bpos_to_text(out, btree_node_pos(_b, cached));
}
#ifdef CONFIG_BCACHEFS_DEBUG_TRANSACTIONS
static bool trans_has_locks(struct btree_trans *trans)
{
struct btree_path *path;
trans_for_each_path(trans, path)
if (path->nodes_locked)
return true;
return false;
}
#endif
void bch2_btree_trans_to_text(struct printbuf *out, struct bch_fs *c)
{
#ifdef CONFIG_BCACHEFS_DEBUG_TRANSACTIONS
struct btree_trans *trans;
struct btree_path *path;
struct btree *b;
static char lock_types[] = { 'r', 'i', 'w' };
unsigned l;
mutex_lock(&c->btree_trans_lock);
list_for_each_entry(trans, &c->btree_trans_list, list) {
if (!trans_has_locks(trans))
continue;
pr_buf(out, "%i %s\n", trans->pid, trans->fn);
trans_for_each_path(trans, path) {
if (!path->nodes_locked)
continue;
pr_buf(out, " path %u %c l=%u %s:",
path->idx,
path->cached ? 'c' : 'b',
path->level,
bch2_btree_ids[path->btree_id]);
bch2_bpos_to_text(out, path->pos);
pr_buf(out, "\n");
for (l = 0; l < BTREE_MAX_DEPTH; l++) {
if (btree_node_locked(path, l)) {
pr_buf(out, " %s l=%u ",
btree_node_intent_locked(path, l) ? "i" : "r", l);
bch2_btree_path_node_to_text(out,
(void *) path->l[l].b,
path->cached);
pr_buf(out, "\n");
}
}
}
b = READ_ONCE(trans->locking);
if (b) {
path = &trans->paths[trans->locking_path_idx];
pr_buf(out, " locking path %u %c l=%u %c %s:",
trans->locking_path_idx,
path->cached ? 'c' : 'b',
trans->locking_level,
lock_types[trans->locking_lock_type],
bch2_btree_ids[trans->locking_btree_id]);
bch2_bpos_to_text(out, trans->locking_pos);
pr_buf(out, " node ");
bch2_btree_path_node_to_text(out,
(void *) b, path->cached);
pr_buf(out, "\n");
}
}
mutex_unlock(&c->btree_trans_lock);
#endif
}
void bch2_fs_btree_iter_exit(struct bch_fs *c)
{
if (c->btree_trans_barrier_initialized)
cleanup_srcu_struct(&c->btree_trans_barrier);
mempool_exit(&c->btree_trans_mem_pool);
mempool_exit(&c->btree_paths_pool);
}
int bch2_fs_btree_iter_init(struct bch_fs *c)
{
unsigned nr = BTREE_ITER_MAX;
int ret;
INIT_LIST_HEAD(&c->btree_trans_list);
mutex_init(&c->btree_trans_lock);
ret = mempool_init_kmalloc_pool(&c->btree_paths_pool, 1,
sizeof(struct btree_path) * nr +
sizeof(struct btree_insert_entry) * nr) ?:
mempool_init_kmalloc_pool(&c->btree_trans_mem_pool, 1,
BTREE_TRANS_MEM_MAX) ?:
init_srcu_struct(&c->btree_trans_barrier);
if (!ret)
c->btree_trans_barrier_initialized = true;
return ret;
}
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