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c4accde498
linux/fs/bcachefs/btree_iter.c
Kent Overstreet c4accde498 bcachefs: Ensure srcu lock is not held too long 
The SRCU read lock that btree_trans takes exists to make it safe for
bch2_trans_relock() to deref pointers to btree nodes/key cache items we
don't have locked, but as a side effect it blocks reclaim from freeing
those items.

Thus, it's important to not hold it for too long: we need to
differentiate between bch2_trans_unlock() calls that will be only for a
short duration, and ones that will be for an unbounded duration.

This introduces bch2_trans_unlock_long(), to be used mainly by the data
move paths.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-11-04 14:17:11 -04:00

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// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "bkey_methods.h"
#include "bkey_buf.h"
#include "btree_cache.h"
#include "btree_iter.h"
#include "btree_journal_iter.h"
#include "btree_key_cache.h"
#include "btree_locking.h"
#include "btree_update.h"
#include "debug.h"
#include "error.h"
#include "extents.h"
#include "journal.h"
#include "replicas.h"
#include "snapshot.h"
#include "trace.h"
#include <linux/random.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 inline unsigned long btree_iter_ip_allocated(struct btree_iter *iter)
{
#ifdef TRACK_PATH_ALLOCATED
return iter->ip_allocated;
#else
return 0;
#endif
}
static struct btree_path *btree_path_alloc(struct btree_trans *, struct btree_path *);
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 struct bpos btree_iter_search_key(struct btree_iter *iter)
{
struct bpos pos = iter->pos;
if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
!bkey_eq(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_lt(path->pos, b->data->min_key);
}
static inline bool btree_path_pos_after_node(struct btree_path *path,
struct btree *b)
{
return bpos_gt(path->pos, b->key.k.p);
}
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 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_eq(ck->key.pos, path->pos));
if (!locked)
btree_node_unlock(trans, 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;
struct printbuf buf1 = PRINTBUF;
struct printbuf buf2 = PRINTBUF;
struct printbuf buf3 = PRINTBUF;
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_notrace(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(trans, path, level);
return;
err:
bch2_bpos_to_text(&buf1, path->pos);
if (p) {
struct bkey uk = bkey_unpack_key(l->b, p);
bch2_bkey_to_text(&buf2, &uk);
} else {
prt_printf(&buf2, "(none)");
}
if (k) {
struct bkey uk = bkey_unpack_key(l->b, k);
bch2_bkey_to_text(&buf3, &uk);
} else {
prt_printf(&buf3, "(none)");
}
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.buf, buf2.buf, buf3.buf);
}
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 &&
bch2_btree_id_root(c, 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_lt(iter->pos, bkey_start_pos(&iter->k)) ||
bkey_gt(iter->pos, iter->k.p));
}
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_eq(prev.k->p, k.k->p) &&
bch2_snapshot_is_ancestor(trans->c, iter->snapshot,
prev.k->p.snapshot) > 0) {
struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
bch2_bkey_to_text(&buf1, k.k);
bch2_bkey_to_text(&buf2, prev.k);
panic("iter snap %u\n"
"k %s\n"
"prev %s\n",
iter->snapshot,
buf1.buf, buf2.buf);
}
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;
struct printbuf buf = PRINTBUF;
btree_trans_sort_paths(trans);
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 (!btree_node_locked(path, 0) ||
!path->should_be_locked)
continue;
if (!key_cache) {
if (bkey_ge(pos, path->l[0].b->data->min_key) &&
bkey_le(pos, path->l[0].b->key.k.p))
return;
} else {
if (bkey_eq(pos, path->pos))
return;
}
}
bch2_dump_trans_paths_updates(trans);
bch2_bpos_to_text(&buf, pos);
panic("not locked: %s %s%s\n",
bch2_btree_id_str(id), buf.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 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;
bch2_btree_path_verify_level(trans, path, l - path->l);
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;
bch2_btree_path_verify_level(trans, path, l - path->l);
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;
}
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);
}
void bch2_btree_path_level_init(struct btree_trans *trans,
struct btree_path *path,
struct btree *b)
{
BUG_ON(path->cached);
EBUG_ON(!btree_path_pos_in_node(path, b));
path->l[b->c.level].lock_seq = six_lock_seq(&b->c.lock);
path->l[b->c.level].b = b;
__btree_path_level_init(path, b->c.level);
}
/* Btree path: fixups after btree node updates: */
static void bch2_trans_revalidate_updates_in_node(struct btree_trans *trans, struct btree *b)
{
struct bch_fs *c = trans->c;
struct btree_insert_entry *i;
trans_for_each_update(trans, i)
if (!i->cached &&
i->level == b->c.level &&
i->btree_id == b->c.btree_id &&
bpos_cmp(i->k->k.p, b->data->min_key) >= 0 &&
bpos_cmp(i->k->k.p, b->data->max_key) <= 0) {
i->old_v = bch2_btree_path_peek_slot(i->path, &i->old_k).v;
if (unlikely(trans->journal_replay_not_finished)) {
struct bkey_i *j_k =
bch2_journal_keys_peek_slot(c, i->btree_id, i->level,
i->k->k.p);
if (j_k) {
i->old_k = j_k->k;
i->old_v = &j_k->v;
}
}
}
}
/*
* 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->uptodate == BTREE_ITER_UPTODATE &&
!path->cached &&
btree_path_pos_in_node(path, b)) {
enum btree_node_locked_type t =
btree_lock_want(path, b->c.level);
if (t != BTREE_NODE_UNLOCKED) {
btree_node_unlock(trans, path, b->c.level);
six_lock_increment(&b->c.lock, (enum six_lock_type) t);
mark_btree_node_locked(trans, path, b->c.level, t);
}
bch2_btree_path_level_init(trans, path, b);
}
bch2_trans_revalidate_updates_in_node(trans, 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);
bch2_trans_revalidate_updates_in_node(trans, b);
}
/* Btree path: traverse, set_pos: */
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 = &bch2_btree_id_root(c, path->btree_id)->b;
enum six_lock_type lock_type;
unsigned i;
int ret;
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);
ret = btree_node_lock(trans, path, &b->c,
path->level, lock_type, trace_ip);
if (unlikely(ret)) {
if (bch2_err_matches(ret, BCH_ERR_lock_fail_root_changed))
continue;
if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
return ret;
BUG();
}
if (likely(b == READ_ONCE(*rootp) &&
b->c.level == path->level &&
!race_fault())) {
for (i = 0; i < path->level; i++)
path->l[i].b = ERR_PTR(-BCH_ERR_no_btree_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(trans, path, path->level,
(enum btree_node_locked_type) lock_type);
bch2_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(trans, path, tmp.k, path->btree_id,
path->level - 1);
}
if (!was_locked)
btree_node_unlock(trans, 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(trans, path, tmp.k, path->btree_id,
path->level - 1);
}
if (!was_locked)
btree_node_unlock(trans, 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(trans, 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;
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(trans, path, level + 1);
mark_btree_node_locked(trans, path, level,
(enum btree_node_locked_type) lock_type);
path->level = level;
bch2_btree_path_level_init(trans, path, b);
bch2_btree_path_verify_locks(path);
err:
bch2_bkey_buf_exit(&tmp, c);
return ret;
}
static int bch2_btree_path_traverse_all(struct btree_trans *trans)
{
struct bch_fs *c = trans->c;
struct btree_path *path;
unsigned long trace_ip = _RET_IP_;
int i, ret = 0;
if (trans->in_traverse_all)
return -BCH_ERR_transaction_restart_in_traverse_all;
trans->in_traverse_all = true;
retry_all:
trans->restarted = 0;
trans->last_restarted_ip = 0;
trans_for_each_path(trans, path)
path->should_be_locked = false;
btree_trans_sort_paths(trans);
bch2_trans_unlock(trans);
cond_resched();
if (unlikely(trans->memory_allocation_failure)) {
struct closure cl;
closure_init_stack(&cl);
do {
ret = bch2_btree_cache_cannibalize_lock(c, &cl);
closure_sync(&cl);
} while (ret);
}
/* 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) {
__btree_path_get(path, false);
ret = bch2_btree_path_traverse_one(trans, path, 0, _THIS_IP_);
__btree_path_put(path, false);
if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||
bch2_err_matches(ret, ENOMEM))
goto retry_all;
if (ret)
goto err;
} else {
i++;
}
}
/*
* We used to assert that all paths had been traversed here
* (path->uptodate < BTREE_ITER_NEED_TRAVERSE); however, since
* path->should_be_locked is not set yet, we might have unlocked and
* then failed to relock a path - that's fine.
*/
err:
bch2_btree_cache_cannibalize_unlock(c);
trans->in_traverse_all = false;
trace_and_count(c, trans_traverse_all, trans, trace_ip);
return ret;
}
static inline bool btree_path_check_pos_in_node(struct btree_path *path,
unsigned l, int check_pos)
{
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 bool btree_path_good_node(struct btree_trans *trans,
struct btree_path *path,
unsigned l, int check_pos)
{
return is_btree_node(path, l) &&
bch2_btree_node_relock(trans, path, l) &&
btree_path_check_pos_in_node(path, l, check_pos);
}
static void btree_path_set_level_down(struct btree_trans *trans,
struct btree_path *path,
unsigned new_level)
{
unsigned l;
path->level = new_level;
for (l = path->level + 1; l < BTREE_MAX_DEPTH; l++)
if (btree_lock_want(path, l) == BTREE_NODE_UNLOCKED)
btree_node_unlock(trans, path, l);
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
bch2_btree_path_verify(trans, path);
}
static noinline unsigned __btree_path_up_until_good_node(struct btree_trans *trans,
struct btree_path *path,
int check_pos)
{
unsigned i, l = path->level;
again:
while (btree_path_node(path, l) &&
!btree_path_good_node(trans, path, l, check_pos))
__btree_path_set_level_up(trans, path, 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_path_set_level_up(trans, path, l++);
goto again;
}
return l;
}
static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,
struct btree_path *path,
int check_pos)
{
return likely(btree_node_locked(path, path->level) &&
btree_path_check_pos_in_node(path, path->level, check_pos))
? path->level
: __btree_path_up_until_good_node(trans, path, check_pos);
}
/*
* 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().
*/
int bch2_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 = -((int) trans->restarted);
if (unlikely(ret))
goto out;
if (unlikely(!trans->srcu_held))
bch2_trans_srcu_lock(trans);
/*
* 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);
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);
EBUG_ON(btree_path_node(path, path->level) &&
!btree_node_locked(path, path->level));
/*
* 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(trans, path);
path->level = depth_want;
path->l[path->level].b = ERR_PTR(ret);
goto out;
}
}
path->uptodate = BTREE_ITER_UPTODATE;
out:
if (bch2_err_matches(ret, BCH_ERR_transaction_restart) != !!trans->restarted)
panic("ret %s (%i) trans->restarted %s (%i)\n",
bch2_err_str(ret), ret,
bch2_err_str(trans->restarted), trans->restarted);
bch2_btree_path_verify(trans, path);
return ret;
}
static inline 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++) {
unsigned t = btree_node_locked_type(dst, i);
if (t != BTREE_NODE_UNLOCKED)
six_lock_increment(&dst->l[i].b->c.lock, t);
}
}
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;
}
__flatten
struct btree_path *__bch2_btree_path_make_mut(struct btree_trans *trans,
struct btree_path *path, bool intent,
unsigned long ip)
{
__btree_path_put(path, intent);
path = btree_path_clone(trans, path, intent);
path->preserve = false;
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, unsigned long ip, int cmp)
{
unsigned level = path->level;
bch2_trans_verify_not_in_restart(trans);
EBUG_ON(!path->ref);
path = bch2_btree_path_make_mut(trans, path, intent, ip);
path->pos = new_pos;
trans->paths_sorted = false;
if (unlikely(path->cached)) {
btree_node_unlock(trans, path, 0);
path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_up);
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
goto out;
}
level = btree_path_up_until_good_node(trans, path, cmp);
if (btree_path_node(path, level)) {
struct btree_path_level *l = &path->l[level];
BUG_ON(!btree_node_locked(path, level));
/*
* We might have to skip over many keys, or just a few: try
* advancing the node iterator, and if we have to skip over too
* many keys just reinit it (or if we're rewinding, since that
* is expensive).
*/
if (cmp < 0 ||
!btree_path_advance_to_pos(path, l, 8))
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 (unlikely(level))
bch2_btree_node_iter_peek(&l->iter, l->b);
}
if (unlikely(level != path->level)) {
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
__bch2_btree_path_unlock(trans, 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 *sib;
sib = prev_btree_path(trans, path);
if (sib && !btree_path_cmp(sib, path))
return sib;
sib = next_btree_path(trans, path);
if (sib && !btree_path_cmp(sib, path))
return sib;
return NULL;
}
static struct btree_path *have_node_at_pos(struct btree_trans *trans, struct btree_path *path)
{
struct btree_path *sib;
sib = prev_btree_path(trans, path);
if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)
return sib;
sib = next_btree_path(trans, path);
if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)
return sib;
return NULL;
}
static inline void __bch2_path_free(struct btree_trans *trans, struct btree_path *path)
{
__bch2_btree_path_unlock(trans, 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;
dup = path->preserve
? have_path_at_pos(trans, path)
: have_node_at_pos(trans, path);
if (!dup && !(!path->preserve && !is_btree_node(path, path->level)))
return;
if (path->should_be_locked &&
!trans->restarted &&
(!dup || !bch2_btree_path_relock_norestart(trans, dup, _THIS_IP_)))
return;
if (dup) {
dup->preserve |= path->preserve;
dup->should_be_locked |= path->should_be_locked;
}
__bch2_path_free(trans, path);
}
static void bch2_path_put_nokeep(struct btree_trans *trans, struct btree_path *path,
bool intent)
{
EBUG_ON(trans->paths + path->idx != path);
EBUG_ON(!path->ref);
if (!__btree_path_put(path, intent))
return;
__bch2_path_free(trans, path);
}
void __noreturn bch2_trans_restart_error(struct btree_trans *trans, u32 restart_count)
{
panic("trans->restart_count %u, should be %u, last restarted by %pS\n",
trans->restart_count, restart_count,
(void *) trans->last_begin_ip);
}
void __noreturn bch2_trans_in_restart_error(struct btree_trans *trans)
{
panic("in transaction restart: %s, last restarted by %pS\n",
bch2_err_str(trans->restarted),
(void *) trans->last_restarted_ip);
}
noinline __cold
void bch2_trans_updates_to_text(struct printbuf *buf, struct btree_trans *trans)
{
struct btree_insert_entry *i;
struct btree_write_buffered_key *wb;
prt_printf(buf, "transaction updates for %s journal seq %llu",
trans->fn, trans->journal_res.seq);
prt_newline(buf);
printbuf_indent_add(buf, 2);
trans_for_each_update(trans, i) {
struct bkey_s_c old = { &i->old_k, i->old_v };
prt_printf(buf, "update: btree=%s cached=%u %pS",
bch2_btree_id_str(i->btree_id),
i->cached,
(void *) i->ip_allocated);
prt_newline(buf);
prt_printf(buf, " old ");
bch2_bkey_val_to_text(buf, trans->c, old);
prt_newline(buf);
prt_printf(buf, " new ");
bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(i->k));
prt_newline(buf);
}
trans_for_each_wb_update(trans, wb) {
prt_printf(buf, "update: btree=%s wb=1 %pS",
bch2_btree_id_str(wb->btree),
(void *) i->ip_allocated);
prt_newline(buf);
prt_printf(buf, " new ");
bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(&wb->k));
prt_newline(buf);
}
printbuf_indent_sub(buf, 2);
}
noinline __cold
void bch2_dump_trans_updates(struct btree_trans *trans)
{
struct printbuf buf = PRINTBUF;
bch2_trans_updates_to_text(&buf, trans);
bch2_print_string_as_lines(KERN_ERR, buf.buf);
printbuf_exit(&buf);
}
noinline __cold
void bch2_btree_path_to_text(struct printbuf *out, struct btree_path *path)
{
prt_printf(out, "path: idx %2u ref %u:%u %c %c btree=%s l=%u pos ",
path->idx, path->ref, path->intent_ref,
path->preserve ? 'P' : ' ',
path->should_be_locked ? 'S' : ' ',
bch2_btree_id_str(path->btree_id),
path->level);
bch2_bpos_to_text(out, path->pos);
prt_printf(out, " locks %u", path->nodes_locked);
#ifdef TRACK_PATH_ALLOCATED
prt_printf(out, " %pS", (void *) path->ip_allocated);
#endif
prt_newline(out);
}
static noinline __cold
void __bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans,
bool nosort)
{
struct btree_path *path;
unsigned idx;
if (!nosort)
btree_trans_sort_paths(trans);
trans_for_each_path_inorder(trans, path, idx)
bch2_btree_path_to_text(out, path);
}
noinline __cold
void bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans)
{
__bch2_trans_paths_to_text(out, trans, false);
}
static noinline __cold
void __bch2_dump_trans_paths_updates(struct btree_trans *trans, bool nosort)
{
struct printbuf buf = PRINTBUF;
__bch2_trans_paths_to_text(&buf, trans, nosort);
bch2_trans_updates_to_text(&buf, trans);
bch2_print_string_as_lines(KERN_ERR, buf.buf);
printbuf_exit(&buf);
}
noinline __cold
void bch2_dump_trans_paths_updates(struct btree_trans *trans)
{
__bch2_dump_trans_paths_updates(trans, false);
}
noinline __cold
static void bch2_trans_update_max_paths(struct btree_trans *trans)
{
struct btree_transaction_stats *s = btree_trans_stats(trans);
struct printbuf buf = PRINTBUF;
if (!s)
return;
bch2_trans_paths_to_text(&buf, trans);
if (!buf.allocation_failure) {
mutex_lock(&s->lock);
if (s->nr_max_paths < hweight64(trans->paths_allocated)) {
s->nr_max_paths = trans->nr_max_paths =
hweight64(trans->paths_allocated);
swap(s->max_paths_text, buf.buf);
}
mutex_unlock(&s->lock);
}
printbuf_exit(&buf);
trans->nr_max_paths = hweight64(trans->paths_allocated);
}
static noinline void btree_path_overflow(struct btree_trans *trans)
{
bch2_dump_trans_paths_updates(trans);
panic("trans path overflow\n");
}
static inline 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))))
btree_path_overflow(trans);
idx = __ffs64(~trans->paths_allocated);
/*
* Do this before marking the new path as allocated, since it won't be
* initialized yet:
*/
if (unlikely(idx > trans->nr_max_paths))
bch2_trans_update_max_paths(trans);
trans->paths_allocated |= 1ULL << idx;
path = &trans->paths[idx];
path->idx = idx;
path->ref = 0;
path->intent_ref = 0;
path->nodes_locked = 0;
path->alloc_seq++;
btree_path_list_add(trans, pos, path);
trans->paths_sorted = false;
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, unsigned long ip)
{
struct btree_path *path, *path_pos = NULL;
bool cached = flags & BTREE_ITER_CACHED;
bool intent = flags & BTREE_ITER_INTENT;
int i;
bch2_trans_verify_not_in_restart(trans);
bch2_trans_verify_locks(trans);
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, ip);
} 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;
for (i = 0; i < ARRAY_SIZE(path->l); i++)
path->l[i].b = ERR_PTR(-BCH_ERR_no_btree_node_init);
#ifdef TRACK_PATH_ALLOCATED
path->ip_allocated = 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)
bch2_btree_path_upgrade_noupgrade_sibs(trans, path, locks_want, NULL);
return path;
}
struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *path, struct bkey *u)
{
struct btree_path_level *l = path_l(path);
struct bkey_packed *_k;
struct bkey_s_c k;
if (unlikely(!l->b))
return bkey_s_c_null;
EBUG_ON(path->uptodate != BTREE_ITER_UPTODATE);
EBUG_ON(!btree_node_locked(path, path->level));
if (!path->cached) {
_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_eq(k.k->p, path->pos));
if (!k.k || !bpos_eq(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_eq(path->pos, ck->key.pos)));
if (!ck || !ck->valid)
return bkey_s_c_null;
*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,
btree_iter_ip_allocated(iter));
ret = bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);
if (ret)
return ret;
btree_path_set_should_be_locked(iter->path);
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_lt(b->key.k.p, iter->pos));
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,
btree_iter_ip_allocated(iter));
btree_path_set_should_be_locked(iter->path);
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_peek_node_and_restart(struct btree_iter *iter)
{
struct btree *b;
while (b = bch2_btree_iter_peek_node(iter),
bch2_err_matches(PTR_ERR_OR_ZERO(b), BCH_ERR_transaction_restart))
bch2_trans_begin(iter->trans);
return b;
}
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;
int ret;
bch2_trans_verify_not_in_restart(trans);
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_path_set_level_up(trans, path);
return NULL;
}
if (!bch2_btree_node_relock(trans, path, path->level + 1)) {
__bch2_btree_path_unlock(trans, path);
path->l[path->level].b = ERR_PTR(-BCH_ERR_no_btree_node_relock);
path->l[path->level + 1].b = ERR_PTR(-BCH_ERR_no_btree_node_relock);
btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
trace_and_count(trans->c, trans_restart_relock_next_node, trans, _THIS_IP_, path);
ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_relock);
goto err;
}
b = btree_path_node(path, path->level + 1);
if (bpos_eq(iter->pos, b->key.k.p)) {
__btree_path_set_level_up(trans, path, 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,
btree_iter_ip_allocated(iter));
btree_path_set_level_down(trans, path, iter->min_depth);
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,
btree_iter_ip_allocated(iter));
btree_path_set_should_be_locked(iter->path);
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)
{
if (likely(!(iter->flags & BTREE_ITER_ALL_LEVELS))) {
struct bpos pos = iter->k.p;
bool ret = !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS
? bpos_eq(pos, SPOS_MAX)
: bkey_eq(pos, SPOS_MAX));
if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
pos = bkey_successor(iter, pos);
bch2_btree_iter_set_pos(iter, pos);
return ret;
} else {
if (!btree_path_node(iter->path, iter->path->level))
return true;
iter->advanced = true;
return false;
}
}
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_eq(pos, POS_MIN)
: bkey_eq(pos, POS_MIN));
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_lt(i->k->k.p, iter->path->pos))
continue;
if (i->key_cache_already_flushed)
continue;
if (!ret || bpos_lt(i->k->k.p, ret->k.p))
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 struct bkey_i *bch2_btree_journal_peek(struct btree_trans *trans,
struct btree_iter *iter,
struct bpos end_pos)
{
struct bkey_i *k;
if (bpos_lt(iter->path->pos, iter->journal_pos))
iter->journal_idx = 0;
k = bch2_journal_keys_peek_upto(trans->c, iter->btree_id,
iter->path->level,
iter->path->pos,
end_pos,
&iter->journal_idx);
iter->journal_pos = k ? k->k.p : end_pos;
return k;
}
static noinline
struct bkey_s_c btree_trans_peek_slot_journal(struct btree_trans *trans,
struct btree_iter *iter)
{
struct bkey_i *k = bch2_btree_journal_peek(trans, iter, iter->path->pos);
if (k) {
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_btree_journal_peek(trans, iter,
k.k ? k.k->p : path_l(iter->path)->b->key.k.p);
if (next_journal) {
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;
struct bkey_s_c k;
int ret;
if ((iter->flags & BTREE_ITER_KEY_CACHE_FILL) &&
bpos_eq(iter->pos, pos))
return bkey_s_c_null;
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|
BTREE_ITER_CACHED_NOFILL,
_THIS_IP_);
iter->key_cache_path = bch2_btree_path_set_pos(trans, iter->key_cache_path, pos,
iter->flags & BTREE_ITER_INTENT,
btree_iter_ip_allocated(iter));
ret = bch2_btree_path_traverse(trans, iter->key_cache_path,
iter->flags|BTREE_ITER_CACHED) ?:
bch2_btree_path_relock(trans, iter->path, _THIS_IP_);
if (unlikely(ret))
return bkey_s_c_err(ret);
btree_path_set_should_be_locked(iter->key_cache_path);
k = bch2_btree_path_peek_slot(iter->key_cache_path, &u);
if (k.k && !bkey_err(k)) {
iter->k = u;
k.k = &iter->k;
}
return k;
}
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);
bch2_btree_iter_verify(iter);
while (1) {
struct btree_path_level *l;
iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
iter->flags & BTREE_ITER_INTENT,
btree_iter_ip_allocated(iter));
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;
}
l = path_l(iter->path);
if (unlikely(!l->b)) {
/* No btree nodes at requested level: */
bch2_btree_iter_set_pos(iter, SPOS_MAX);
k = bkey_s_c_null;
goto out;
}
btree_path_set_should_be_locked(iter->path);
k = btree_path_level_peek_all(trans->c, l, &iter->k);
if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
k.k &&
(k2 = btree_trans_peek_key_cache(iter, k.k->p)).k) {
k = k2;
ret = bkey_err(k);
if (ret) {
bch2_btree_iter_set_pos(iter, iter->pos);
goto out;
}
}
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_le(next_update->k.p,
k.k ? k.k->p : l->b->key.k.p)) {
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_eq(search_key, k.k->p)
? k.k->p
: bpos_successor(k.k->p);
continue;
}
if (likely(k.k)) {
break;
} else if (likely(!bpos_eq(l->b->key.k.p, SPOS_MAX))) {
/* Advance to next leaf node: */
search_key = bpos_successor(l->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_upto() - returns first key greater than or equal to
* iterator's current position
* @iter: iterator to peek from
* @end: search limit: returns keys less than or equal to @end
*
* Returns: key if found, or an error extractable with bkey_err().
*/
struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *iter, struct bpos end)
{
struct btree_trans *trans = iter->trans;
struct bpos search_key = btree_iter_search_key(iter);
struct bkey_s_c k;
struct bpos iter_pos;
int ret;
EBUG_ON(iter->flags & BTREE_ITER_ALL_LEVELS);
EBUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) && bkey_eq(end, POS_MAX));
if (iter->update_path) {
bch2_path_put_nokeep(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 (unlikely(!k.k))
goto end;
if (unlikely(bkey_err(k)))
goto out_no_locked;
/*
* 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
iter_pos = bkey_max(iter->pos, bkey_start_pos(k.k));
if (unlikely(!(iter->flags & BTREE_ITER_IS_EXTENTS)
? bkey_gt(iter_pos, end)
: bkey_ge(iter_pos, end)))
goto end;
if (iter->update_path &&
!bkey_eq(iter->update_path->pos, k.k->p)) {
bch2_path_put_nokeep(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,
_THIS_IP_);
ret = bch2_btree_path_traverse(trans, iter->update_path, iter->flags);
if (unlikely(ret)) {
k = bkey_s_c_err(ret);
goto out_no_locked;
}
}
/*
* 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 = iter_pos;
iter->path = bch2_btree_path_set_pos(trans, iter->path, k.k->p,
iter->flags & BTREE_ITER_INTENT,
btree_iter_ip_allocated(iter));
btree_path_set_should_be_locked(iter->path);
out_no_locked:
if (iter->update_path) {
ret = bch2_btree_path_relock(trans, iter->update_path, _THIS_IP_);
if (unlikely(ret))
k = bkey_s_c_err(ret);
else
btree_path_set_should_be_locked(iter->update_path);
}
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;
end:
bch2_btree_iter_set_pos(iter, end);
k = bkey_s_c_null;
goto out_no_locked;
}
/**
* bch2_btree_iter_peek_all_levels() - returns the first key greater than or
* equal to iterator's current position, returning keys from every level of the
* btree. For keys at different levels of the btree that compare equal, the key
* from the lower level (leaf) is returned first.
* @iter: iterator to peek from
*
* Returns: key if found, or an error extractable with bkey_err().
*/
struct bkey_s_c bch2_btree_iter_peek_all_levels(struct btree_iter *iter)
{
struct btree_trans *trans = iter->trans;
struct bkey_s_c k;
int ret;
EBUG_ON(iter->path->cached);
bch2_btree_iter_verify(iter);
BUG_ON(iter->path->level < iter->min_depth);
BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
EBUG_ON(!(iter->flags & BTREE_ITER_ALL_LEVELS));
while (1) {
iter->path = bch2_btree_path_set_pos(trans, iter->path, iter->pos,
iter->flags & BTREE_ITER_INTENT,
btree_iter_ip_allocated(iter));
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_no_locked;
}
/* Already at end? */
if (!btree_path_node(iter->path, iter->path->level)) {
k = bkey_s_c_null;
goto out_no_locked;
}
k = btree_path_level_peek_all(trans->c,
&iter->path->l[iter->path->level], &iter->k);
/* Check if we should go up to the parent node: */
if (!k.k ||
(iter->advanced &&
bpos_eq(path_l(iter->path)->b->key.k.p, iter->pos))) {
iter->pos = path_l(iter->path)->b->key.k.p;
btree_path_set_level_up(trans, iter->path);
iter->advanced = false;
continue;
}
/*
* Check if we should go back down to a leaf:
* If we're not in a leaf node, we only return the current key
* if it exactly matches iter->pos - otherwise we first have to
* go back to the leaf:
*/
if (iter->path->level != iter->min_depth &&
(iter->advanced ||
!k.k ||
!bpos_eq(iter->pos, k.k->p))) {
btree_path_set_level_down(trans, iter->path, iter->min_depth);
iter->pos = bpos_successor(iter->pos);
iter->advanced = false;
continue;
}
/* Check if we should go to the next key: */
if (iter->path->level == iter->min_depth &&
iter->advanced &&
k.k &&
bpos_eq(iter->pos, k.k->p)) {
iter->pos = bpos_successor(iter->pos);
iter->advanced = false;
continue;
}
if (iter->advanced &&
iter->path->level == iter->min_depth &&
!bpos_eq(k.k->p, iter->pos))
iter->advanced = false;
BUG_ON(iter->advanced);
BUG_ON(!k.k);
break;
}
iter->pos = k.k->p;
btree_path_set_should_be_locked(iter->path);
out_no_locked:
bch2_btree_iter_verify(iter);
return k;
}
/**
* bch2_btree_iter_next() - returns first key greater than iterator's current
* position
* @iter: iterator to peek from
*
* Returns: key if found, or an error extractable with bkey_err().
*/
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
* @iter: iterator to peek from
*
* Returns: key if found, or an error extractable with bkey_err().
*/
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,
btree_iter_ip_allocated(iter));
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_no_locked;
}
k = btree_path_level_peek(trans, iter->path,
&iter->path->l[0], &iter->k);
if (!k.k ||
((iter->flags & BTREE_ITER_IS_EXTENTS)
? bpos_ge(bkey_start_pos(k.k), search_key)
: bpos_gt(k.k->p, search_key)))
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_eq(k.k->p, saved_k.p)) {
bch2_path_put_nokeep(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_nokeep(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_eq(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_no_locked;
}
}
EBUG_ON(bkey_gt(bkey_start_pos(k.k), iter->pos));
/* Extents can straddle iter->pos: */
if (bkey_lt(k.k->p, iter->pos))
iter->pos = k.k->p;
if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
iter->pos.snapshot = iter->snapshot;
btree_path_set_should_be_locked(iter->path);
out_no_locked:
if (saved_path)
bch2_path_put_nokeep(trans, saved_path, iter->flags & BTREE_ITER_INTENT);
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
* @iter: iterator to peek from
*
* Returns: key if found, or an error extractable with bkey_err().
*/
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;
bch2_btree_iter_verify(iter);
bch2_btree_iter_verify_entry_exit(iter);
EBUG_ON(iter->flags & BTREE_ITER_ALL_LEVELS);
EBUG_ON(iter->path->level && (iter->flags & BTREE_ITER_WITH_KEY_CACHE));
/* 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,
btree_iter_ip_allocated(iter));
ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
if (unlikely(ret)) {
k = bkey_s_c_err(ret);
goto out_no_locked;
}
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_eq(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;
/* We're not returning a key from iter->path: */
goto out_no_locked;
}
k = bch2_btree_path_peek_slot(iter->path, &iter->k);
if (unlikely(!k.k))
goto out_no_locked;
} else {
struct bpos next;
struct bpos end = iter->pos;
if (iter->flags & BTREE_ITER_IS_EXTENTS)
end.offset = U64_MAX;
EBUG_ON(iter->path->level);
if (iter->flags & BTREE_ITER_INTENT) {
struct btree_iter iter2;
bch2_trans_copy_iter(&iter2, iter);
k = bch2_btree_iter_peek_upto(&iter2, end);
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_upto(iter, end);
if (unlikely(bkey_err(k)))
bch2_btree_iter_set_pos(iter, pos);
else
iter->pos = pos;
}
if (unlikely(bkey_err(k)))
goto out_no_locked;
next = k.k ? bkey_start_pos(k.k) : POS_MAX;
if (bkey_lt(iter->pos, next)) {
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:
btree_path_set_should_be_locked(iter->path);
out_no_locked:
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);
}
struct bkey_s_c bch2_btree_iter_peek_and_restart_outlined(struct btree_iter *iter)
{
struct bkey_s_c k;
while (btree_trans_too_many_iters(iter->trans) ||
(k = bch2_btree_iter_peek_type(iter, iter->flags),
bch2_err_matches(bkey_err(k), BCH_ERR_transaction_restart)))
bch2_trans_begin(iter->trans);
return k;
}
/* 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;
if (!bch2_debug_check_iterators)
return;
trans_for_each_path_inorder(trans, path, i) {
if (prev && btree_path_cmp(prev, path) > 0) {
__bch2_dump_trans_paths_updates(trans, true);
panic("trans paths out of order!\n");
}
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 sorted.
*/
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->update_path)
bch2_path_put_nokeep(trans, iter->update_path,
iter->flags & BTREE_ITER_INTENT);
if (iter->path)
bch2_path_put(trans, iter->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;
}
void bch2_trans_iter_init_outlined(struct btree_trans *trans,
struct btree_iter *iter,
enum btree_id btree_id, struct bpos pos,
unsigned flags)
{
bch2_trans_iter_init_common(trans, iter, btree_id, pos, 0, 0,
bch2_btree_iter_flags(trans, btree_id, flags),
_RET_IP_);
}
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)
{
flags |= BTREE_ITER_NOT_EXTENTS;
flags |= __BTREE_ITER_ALL_SNAPSHOTS;
flags |= BTREE_ITER_ALL_SNAPSHOTS;
bch2_trans_iter_init_common(trans, iter, btree_id, pos, locks_want, depth,
__bch2_btree_iter_flags(trans, btree_id, flags),
_RET_IP_);
iter->min_depth = depth;
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)
{
unsigned new_top = trans->mem_top + size;
size_t old_bytes = trans->mem_bytes;
size_t new_bytes = roundup_pow_of_two(new_top);
int ret;
void *new_mem;
void *p;
trans->mem_max = max(trans->mem_max, new_top);
WARN_ON_ONCE(new_bytes > BTREE_TRANS_MEM_MAX);
new_mem = krealloc(trans->mem, new_bytes, GFP_NOWAIT|__GFP_NOWARN);
if (unlikely(!new_mem)) {
bch2_trans_unlock(trans);
new_mem = krealloc(trans->mem, new_bytes, GFP_KERNEL);
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(-BCH_ERR_ENOMEM_trans_kmalloc);
trans->mem = new_mem;
trans->mem_bytes = new_bytes;
ret = bch2_trans_relock(trans);
if (ret)
return ERR_PTR(ret);
}
trans->mem = new_mem;
trans->mem_bytes = new_bytes;
if (old_bytes) {
trace_and_count(trans->c, trans_restart_mem_realloced, trans, _RET_IP_, new_bytes);
return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_mem_realloced));
}
p = trans->mem + trans->mem_top;
trans->mem_top += size;
memset(p, 0, size);
return p;
}
void bch2_trans_srcu_unlock(struct btree_trans *trans)
{
if (trans->srcu_held) {
struct bch_fs *c = trans->c;
struct btree_path *path;
trans_for_each_path(trans, path)
if (path->cached && !btree_node_locked(path, 0))
path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_srcu_reset);
srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
trans->srcu_held = false;
}
}
void bch2_trans_srcu_lock(struct btree_trans *trans)
{
if (!trans->srcu_held) {
trans->srcu_idx = srcu_read_lock(&trans->c->btree_trans_barrier);
trans->srcu_lock_time = jiffies;
trans->srcu_held = true;
}
}
/**
* bch2_trans_begin() - reset a transaction after a interrupted attempt
* @trans: transaction to reset
*
* Returns: current restart counter, to be used with trans_was_restarted()
*
* While iterating over nodes or updating nodes a attempt to lock a btree node
* may return BCH_ERR_transaction_restart when the trylock fails. When this
* occurs bch2_trans_begin() should be called and the transaction retried.
*/
u32 bch2_trans_begin(struct btree_trans *trans)
{
struct btree_path *path;
u64 now;
bch2_trans_reset_updates(trans);
trans->restart_count++;
trans->mem_top = 0;
trans_for_each_path(trans, path) {
path->should_be_locked = false;
/*
* If the transaction wasn't restarted, we're presuming to be
* doing something new: dont keep iterators excpt the ones that
* are in use - except for the subvolumes btree:
*/
if (!trans->restarted && path->btree_id != BTREE_ID_subvolumes)
path->preserve = false;
/*
* 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 = false;
}
now = local_clock();
if (!trans->restarted &&
(need_resched() ||
now - trans->last_begin_time > BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS)) {
drop_locks_do(trans, (cond_resched(), 0));
now = local_clock();
}
trans->last_begin_time = now;
if (unlikely(trans->srcu_held &&
time_after(jiffies, trans->srcu_lock_time + msecs_to_jiffies(10))))
bch2_trans_srcu_unlock(trans);
trans->last_begin_ip = _RET_IP_;
if (trans->restarted) {
bch2_btree_path_traverse_all(trans);
trans->notrace_relock_fail = false;
}
return trans->restart_count;
}
static struct btree_trans *bch2_trans_alloc(struct bch_fs *c)
{
struct btree_trans *trans;
if (IS_ENABLED(__KERNEL__)) {
trans = this_cpu_xchg(c->btree_trans_bufs->trans, NULL);
if (trans)
return trans;
}
trans = mempool_alloc(&c->btree_trans_pool, GFP_NOFS);
/*
* paths need to be zeroed, bch2_check_for_deadlock looks at
* paths in other threads
*/
memset(&trans->paths, 0, sizeof(trans->paths));
return trans;
}
const char *bch2_btree_transaction_fns[BCH_TRANSACTIONS_NR];
unsigned bch2_trans_get_fn_idx(const char *fn)
{
unsigned i;
for (i = 0; i < ARRAY_SIZE(bch2_btree_transaction_fns); i++)
if (!bch2_btree_transaction_fns[i] ||
bch2_btree_transaction_fns[i] == fn) {
bch2_btree_transaction_fns[i] = fn;
return i;
}
pr_warn_once("BCH_TRANSACTIONS_NR not big enough!");
return i;
}
struct btree_trans *__bch2_trans_get(struct bch_fs *c, unsigned fn_idx)
__acquires(&c->btree_trans_barrier)
{
struct btree_trans *trans;
struct btree_transaction_stats *s;
trans = bch2_trans_alloc(c);
memset(trans, 0, sizeof(*trans));
trans->c = c;
trans->fn = fn_idx < ARRAY_SIZE(bch2_btree_transaction_fns)
? bch2_btree_transaction_fns[fn_idx] : NULL;
trans->last_begin_time = local_clock();
trans->fn_idx = fn_idx;
trans->locking_wait.task = current;
trans->journal_replay_not_finished =
!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags);
closure_init_stack(&trans->ref);
s = btree_trans_stats(trans);
if (s && s->max_mem) {
unsigned expected_mem_bytes = roundup_pow_of_two(s->max_mem);
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;
}
}
if (s) {
trans->nr_max_paths = s->nr_max_paths;
trans->wb_updates_size = s->wb_updates_size;
}
trans->srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
trans->srcu_lock_time = jiffies;
trans->srcu_held = true;
if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
struct btree_trans *pos;
seqmutex_lock(&c->btree_trans_lock);
list_for_each_entry(pos, &c->btree_trans_list, list) {
/*
* We'd much prefer to be stricter here and completely
* disallow multiple btree_trans in the same thread -
* but the data move path calls bch2_write when we
* already have a btree_trans initialized.
*/
BUG_ON(trans->locking_wait.task->pid == pos->locking_wait.task->pid &&
bch2_trans_locked(pos));
if (trans->locking_wait.task->pid < pos->locking_wait.task->pid) {
list_add_tail(&trans->list, &pos->list);
goto list_add_done;
}
}
list_add_tail(&trans->list, &c->btree_trans_list);
list_add_done:
seqmutex_unlock(&c->btree_trans_lock);
}
return trans;
}
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_id_str(path->btree_id),
(void *) path->ip_allocated);
/* Be noisy about this: */
bch2_fatal_error(c);
#endif
}
void bch2_trans_put(struct btree_trans *trans)
__releases(&c->btree_trans_barrier)
{
struct btree_insert_entry *i;
struct bch_fs *c = trans->c;
struct btree_transaction_stats *s = btree_trans_stats(trans);
bch2_trans_unlock(trans);
if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
seqmutex_lock(&c->btree_trans_lock);
list_del(&trans->list);
seqmutex_unlock(&c->btree_trans_lock);
}
closure_sync(&trans->ref);
if (s)
s->max_mem = max(s->max_mem, trans->mem_max);
trans_for_each_update(trans, i)
__btree_path_put(i->path, true);
trans->nr_updates = 0;
check_btree_paths_leaked(trans);
if (trans->srcu_held)
srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
bch2_journal_preres_put(&c->journal, &trans->journal_preres);
kfree(trans->extra_journal_entries.data);
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);
/* Userspace doesn't have a real percpu implementation: */
if (IS_ENABLED(__KERNEL__))
trans = this_cpu_xchg(c->btree_trans_bufs->trans, trans);
if (trans)
mempool_free(trans, &c->btree_trans_pool);
}
static void __maybe_unused
bch2_btree_bkey_cached_common_to_text(struct printbuf *out,
struct btree_bkey_cached_common *b)
{
struct six_lock_count c = six_lock_counts(&b->lock);
struct task_struct *owner;
pid_t pid;
rcu_read_lock();
owner = READ_ONCE(b->lock.owner);
pid = owner ? owner->pid : 0;
rcu_read_unlock();
prt_tab(out);
prt_printf(out, "%px %c l=%u %s:", b, b->cached ? 'c' : 'b',
b->level, bch2_btree_id_str(b->btree_id));
bch2_bpos_to_text(out, btree_node_pos(b));
prt_tab(out);
prt_printf(out, " locks %u:%u:%u held by pid %u",
c.n[0], c.n[1], c.n[2], pid);
}
void bch2_btree_trans_to_text(struct printbuf *out, struct btree_trans *trans)
{
struct btree_path *path;
struct btree_bkey_cached_common *b;
static char lock_types[] = { 'r', 'i', 'w' };
unsigned l, idx;
if (!out->nr_tabstops) {
printbuf_tabstop_push(out, 16);
printbuf_tabstop_push(out, 32);
}
prt_printf(out, "%i %s\n", trans->locking_wait.task->pid, trans->fn);
trans_for_each_path_safe(trans, path, idx) {
if (!path->nodes_locked)
continue;
prt_printf(out, " path %u %c l=%u %s:",
path->idx,
path->cached ? 'c' : 'b',
path->level,
bch2_btree_id_str(path->btree_id));
bch2_bpos_to_text(out, path->pos);
prt_newline(out);
for (l = 0; l < BTREE_MAX_DEPTH; l++) {
if (btree_node_locked(path, l) &&
!IS_ERR_OR_NULL(b = (void *) READ_ONCE(path->l[l].b))) {
prt_printf(out, " %c l=%u ",
lock_types[btree_node_locked_type(path, l)], l);
bch2_btree_bkey_cached_common_to_text(out, b);
prt_newline(out);
}
}
}
b = READ_ONCE(trans->locking);
if (b) {
prt_printf(out, " blocked for %lluus on",
div_u64(local_clock() - trans->locking_wait.start_time,
1000));
prt_newline(out);
prt_printf(out, " %c", lock_types[trans->locking_wait.lock_want]);
bch2_btree_bkey_cached_common_to_text(out, b);
prt_newline(out);
}
}
void bch2_fs_btree_iter_exit(struct bch_fs *c)
{
struct btree_transaction_stats *s;
struct btree_trans *trans;
int cpu;
trans = list_first_entry_or_null(&c->btree_trans_list, struct btree_trans, list);
if (trans)
panic("%s leaked btree_trans\n", trans->fn);
if (c->btree_trans_bufs)
for_each_possible_cpu(cpu)
kfree(per_cpu_ptr(c->btree_trans_bufs, cpu)->trans);
free_percpu(c->btree_trans_bufs);
for (s = c->btree_transaction_stats;
s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
s++) {
kfree(s->max_paths_text);
bch2_time_stats_exit(&s->lock_hold_times);
}
if (c->btree_trans_barrier_initialized)
cleanup_srcu_struct(&c->btree_trans_barrier);
mempool_exit(&c->btree_trans_mem_pool);
mempool_exit(&c->btree_trans_pool);
}
int bch2_fs_btree_iter_init(struct bch_fs *c)
{
struct btree_transaction_stats *s;
int ret;
for (s = c->btree_transaction_stats;
s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
s++) {
bch2_time_stats_init(&s->lock_hold_times);
mutex_init(&s->lock);
}
INIT_LIST_HEAD(&c->btree_trans_list);
seqmutex_init(&c->btree_trans_lock);
c->btree_trans_bufs = alloc_percpu(struct btree_trans_buf);
if (!c->btree_trans_bufs)
return -ENOMEM;
ret = mempool_init_kmalloc_pool(&c->btree_trans_pool, 1,
sizeof(struct btree_trans)) ?:
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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