--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+#include "bcachefs.h"
+#include "bkey_buf.h"
+#include "btree_cache.h"
+#include "btree_io.h"
+#include "btree_iter.h"
+#include "btree_locking.h"
+#include "debug.h"
+#include "errcode.h"
+#include "error.h"
+#include "journal.h"
+#include "trace.h"
+
+#include <linux/prefetch.h>
+#include <linux/sched/mm.h>
+
+const char * const bch2_btree_node_flags[] = {
+#define x(f) #f,
+ BTREE_FLAGS()
+#undef x
+ NULL
+};
+
+void bch2_recalc_btree_reserve(struct bch_fs *c)
+{
+ unsigned i, reserve = 16;
+
+ if (!c->btree_roots_known[0].b)
+ reserve += 8;
+
+ for (i = 0; i < btree_id_nr_alive(c); i++) {
+ struct btree_root *r = bch2_btree_id_root(c, i);
+
+ if (r->b)
+ reserve += min_t(unsigned, 1, r->b->c.level) * 8;
+ }
+
+ c->btree_cache.reserve = reserve;
+}
+
+static inline unsigned btree_cache_can_free(struct btree_cache *bc)
+{
+ return max_t(int, 0, bc->used - bc->reserve);
+}
+
+static void btree_node_to_freedlist(struct btree_cache *bc, struct btree *b)
+{
+ if (b->c.lock.readers)
+ list_move(&b->list, &bc->freed_pcpu);
+ else
+ list_move(&b->list, &bc->freed_nonpcpu);
+}
+
+static void btree_node_data_free(struct bch_fs *c, struct btree *b)
+{
+ struct btree_cache *bc = &c->btree_cache;
+
+ EBUG_ON(btree_node_write_in_flight(b));
+
+ clear_btree_node_just_written(b);
+
+ kvpfree(b->data, btree_bytes(c));
+ b->data = NULL;
+#ifdef __KERNEL__
+ kvfree(b->aux_data);
+#else
+ munmap(b->aux_data, btree_aux_data_bytes(b));
+#endif
+ b->aux_data = NULL;
+
+ bc->used--;
+
+ btree_node_to_freedlist(bc, b);
+}
+
+static int bch2_btree_cache_cmp_fn(struct rhashtable_compare_arg *arg,
+ const void *obj)
+{
+ const struct btree *b = obj;
+ const u64 *v = arg->key;
+
+ return b->hash_val == *v ? 0 : 1;
+}
+
+static const struct rhashtable_params bch_btree_cache_params = {
+ .head_offset = offsetof(struct btree, hash),
+ .key_offset = offsetof(struct btree, hash_val),
+ .key_len = sizeof(u64),
+ .obj_cmpfn = bch2_btree_cache_cmp_fn,
+};
+
+static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
+{
+ BUG_ON(b->data || b->aux_data);
+
+ b->data = kvpmalloc(btree_bytes(c), gfp);
+ if (!b->data)
+ return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
+#ifdef __KERNEL__
+ b->aux_data = kvmalloc(btree_aux_data_bytes(b), gfp);
+#else
+ b->aux_data = mmap(NULL, btree_aux_data_bytes(b),
+ PROT_READ|PROT_WRITE|PROT_EXEC,
+ MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
+ if (b->aux_data == MAP_FAILED)
+ b->aux_data = NULL;
+#endif
+ if (!b->aux_data) {
+ kvpfree(b->data, btree_bytes(c));
+ b->data = NULL;
+ return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
+ }
+
+ return 0;
+}
+
+static struct btree *__btree_node_mem_alloc(struct bch_fs *c, gfp_t gfp)
+{
+ struct btree *b;
+
+ b = kzalloc(sizeof(struct btree), gfp);
+ if (!b)
+ return NULL;
+
+ bkey_btree_ptr_init(&b->key);
+ INIT_LIST_HEAD(&b->list);
+ INIT_LIST_HEAD(&b->write_blocked);
+ b->byte_order = ilog2(btree_bytes(c));
+ return b;
+}
+
+struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *c)
+{
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+
+ b = __btree_node_mem_alloc(c, GFP_KERNEL);
+ if (!b)
+ return NULL;
+
+ if (btree_node_data_alloc(c, b, GFP_KERNEL)) {
+ kfree(b);
+ return NULL;
+ }
+
+ bch2_btree_lock_init(&b->c, 0);
+
+ bc->used++;
+ list_add(&b->list, &bc->freeable);
+ return b;
+}
+
+/* Btree in memory cache - hash table */
+
+void bch2_btree_node_hash_remove(struct btree_cache *bc, struct btree *b)
+{
+ int ret = rhashtable_remove_fast(&bc->table, &b->hash, bch_btree_cache_params);
+
+ BUG_ON(ret);
+
+ /* Cause future lookups for this node to fail: */
+ b->hash_val = 0;
+}
+
+int __bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b)
+{
+ BUG_ON(b->hash_val);
+ b->hash_val = btree_ptr_hash_val(&b->key);
+
+ return rhashtable_lookup_insert_fast(&bc->table, &b->hash,
+ bch_btree_cache_params);
+}
+
+int bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b,
+ unsigned level, enum btree_id id)
+{
+ int ret;
+
+ b->c.level = level;
+ b->c.btree_id = id;
+
+ mutex_lock(&bc->lock);
+ ret = __bch2_btree_node_hash_insert(bc, b);
+ if (!ret)
+ list_add_tail(&b->list, &bc->live);
+ mutex_unlock(&bc->lock);
+
+ return ret;
+}
+
+__flatten
+static inline struct btree *btree_cache_find(struct btree_cache *bc,
+ const struct bkey_i *k)
+{
+ u64 v = btree_ptr_hash_val(k);
+
+ return rhashtable_lookup_fast(&bc->table, &v, bch_btree_cache_params);
+}
+
+/*
+ * this version is for btree nodes that have already been freed (we're not
+ * reaping a real btree node)
+ */
+static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush)
+{
+ struct btree_cache *bc = &c->btree_cache;
+ int ret = 0;
+
+ lockdep_assert_held(&bc->lock);
+wait_on_io:
+ if (b->flags & ((1U << BTREE_NODE_dirty)|
+ (1U << BTREE_NODE_read_in_flight)|
+ (1U << BTREE_NODE_write_in_flight))) {
+ if (!flush)
+ return -BCH_ERR_ENOMEM_btree_node_reclaim;
+
+ /* XXX: waiting on IO with btree cache lock held */
+ bch2_btree_node_wait_on_read(b);
+ bch2_btree_node_wait_on_write(b);
+ }
+
+ if (!six_trylock_intent(&b->c.lock))
+ return -BCH_ERR_ENOMEM_btree_node_reclaim;
+
+ if (!six_trylock_write(&b->c.lock))
+ goto out_unlock_intent;
+
+ /* recheck under lock */
+ if (b->flags & ((1U << BTREE_NODE_read_in_flight)|
+ (1U << BTREE_NODE_write_in_flight))) {
+ if (!flush)
+ goto out_unlock;
+ six_unlock_write(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+ goto wait_on_io;
+ }
+
+ if (btree_node_noevict(b) ||
+ btree_node_write_blocked(b) ||
+ btree_node_will_make_reachable(b))
+ goto out_unlock;
+
+ if (btree_node_dirty(b)) {
+ if (!flush)
+ goto out_unlock;
+ /*
+ * Using the underscore version because we don't want to compact
+ * bsets after the write, since this node is about to be evicted
+ * - unless btree verify mode is enabled, since it runs out of
+ * the post write cleanup:
+ */
+ if (bch2_verify_btree_ondisk)
+ bch2_btree_node_write(c, b, SIX_LOCK_intent,
+ BTREE_WRITE_cache_reclaim);
+ else
+ __bch2_btree_node_write(c, b,
+ BTREE_WRITE_cache_reclaim);
+
+ six_unlock_write(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+ goto wait_on_io;
+ }
+out:
+ if (b->hash_val && !ret)
+ trace_and_count(c, btree_cache_reap, c, b);
+ return ret;
+out_unlock:
+ six_unlock_write(&b->c.lock);
+out_unlock_intent:
+ six_unlock_intent(&b->c.lock);
+ ret = -BCH_ERR_ENOMEM_btree_node_reclaim;
+ goto out;
+}
+
+static int btree_node_reclaim(struct bch_fs *c, struct btree *b)
+{
+ return __btree_node_reclaim(c, b, false);
+}
+
+static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b)
+{
+ return __btree_node_reclaim(c, b, true);
+}
+
+static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct bch_fs *c = shrink->private_data;
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b, *t;
+ unsigned long nr = sc->nr_to_scan;
+ unsigned long can_free = 0;
+ unsigned long freed = 0;
+ unsigned long touched = 0;
+ unsigned i, flags;
+ unsigned long ret = SHRINK_STOP;
+ bool trigger_writes = atomic_read(&bc->dirty) + nr >=
+ bc->used * 3 / 4;
+
+ if (bch2_btree_shrinker_disabled)
+ return SHRINK_STOP;
+
+ mutex_lock(&bc->lock);
+ flags = memalloc_nofs_save();
+
+ /*
+ * It's _really_ critical that we don't free too many btree nodes - we
+ * have to always leave ourselves a reserve. The reserve is how we
+ * guarantee that allocating memory for a new btree node can always
+ * succeed, so that inserting keys into the btree can always succeed and
+ * IO can always make forward progress:
+ */
+ can_free = btree_cache_can_free(bc);
+ nr = min_t(unsigned long, nr, can_free);
+
+ i = 0;
+ list_for_each_entry_safe(b, t, &bc->freeable, list) {
+ /*
+ * Leave a few nodes on the freeable list, so that a btree split
+ * won't have to hit the system allocator:
+ */
+ if (++i <= 3)
+ continue;
+
+ touched++;
+
+ if (touched >= nr)
+ goto out;
+
+ if (!btree_node_reclaim(c, b)) {
+ btree_node_data_free(c, b);
+ six_unlock_write(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+ freed++;
+ }
+ }
+restart:
+ list_for_each_entry_safe(b, t, &bc->live, list) {
+ touched++;
+
+ if (btree_node_accessed(b)) {
+ clear_btree_node_accessed(b);
+ } else if (!btree_node_reclaim(c, b)) {
+ freed++;
+ btree_node_data_free(c, b);
+
+ bch2_btree_node_hash_remove(bc, b);
+ six_unlock_write(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+
+ if (freed == nr)
+ goto out_rotate;
+ } else if (trigger_writes &&
+ btree_node_dirty(b) &&
+ !btree_node_will_make_reachable(b) &&
+ !btree_node_write_blocked(b) &&
+ six_trylock_read(&b->c.lock)) {
+ list_move(&bc->live, &b->list);
+ mutex_unlock(&bc->lock);
+ __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
+ six_unlock_read(&b->c.lock);
+ if (touched >= nr)
+ goto out_nounlock;
+ mutex_lock(&bc->lock);
+ goto restart;
+ }
+
+ if (touched >= nr)
+ break;
+ }
+out_rotate:
+ if (&t->list != &bc->live)
+ list_move_tail(&bc->live, &t->list);
+out:
+ mutex_unlock(&bc->lock);
+out_nounlock:
+ ret = freed;
+ memalloc_nofs_restore(flags);
+ trace_and_count(c, btree_cache_scan, sc->nr_to_scan, can_free, ret);
+ return ret;
+}
+
+static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
+ struct shrink_control *sc)
+{
+ struct bch_fs *c = shrink->private_data;
+ struct btree_cache *bc = &c->btree_cache;
+
+ if (bch2_btree_shrinker_disabled)
+ return 0;
+
+ return btree_cache_can_free(bc);
+}
+
+void bch2_fs_btree_cache_exit(struct bch_fs *c)
+{
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+ unsigned i, flags;
+
+ shrinker_free(bc->shrink);
+
+ /* vfree() can allocate memory: */
+ flags = memalloc_nofs_save();
+ mutex_lock(&bc->lock);
+
+ if (c->verify_data)
+ list_move(&c->verify_data->list, &bc->live);
+
+ kvpfree(c->verify_ondisk, btree_bytes(c));
+
+ for (i = 0; i < btree_id_nr_alive(c); i++) {
+ struct btree_root *r = bch2_btree_id_root(c, i);
+
+ if (r->b)
+ list_add(&r->b->list, &bc->live);
+ }
+
+ list_splice(&bc->freeable, &bc->live);
+
+ while (!list_empty(&bc->live)) {
+ b = list_first_entry(&bc->live, struct btree, list);
+
+ BUG_ON(btree_node_read_in_flight(b) ||
+ btree_node_write_in_flight(b));
+
+ btree_node_data_free(c, b);
+ }
+
+ BUG_ON(!bch2_journal_error(&c->journal) &&
+ atomic_read(&c->btree_cache.dirty));
+
+ list_splice(&bc->freed_pcpu, &bc->freed_nonpcpu);
+
+ while (!list_empty(&bc->freed_nonpcpu)) {
+ b = list_first_entry(&bc->freed_nonpcpu, struct btree, list);
+ list_del(&b->list);
+ six_lock_exit(&b->c.lock);
+ kfree(b);
+ }
+
+ mutex_unlock(&bc->lock);
+ memalloc_nofs_restore(flags);
+
+ if (bc->table_init_done)
+ rhashtable_destroy(&bc->table);
+}
+
+int bch2_fs_btree_cache_init(struct bch_fs *c)
+{
+ struct btree_cache *bc = &c->btree_cache;
+ struct shrinker *shrink;
+ unsigned i;
+ int ret = 0;
+
+ ret = rhashtable_init(&bc->table, &bch_btree_cache_params);
+ if (ret)
+ goto err;
+
+ bc->table_init_done = true;
+
+ bch2_recalc_btree_reserve(c);
+
+ for (i = 0; i < bc->reserve; i++)
+ if (!__bch2_btree_node_mem_alloc(c))
+ goto err;
+
+ list_splice_init(&bc->live, &bc->freeable);
+
+ mutex_init(&c->verify_lock);
+
+ shrink = shrinker_alloc(0, "%s-btree_cache", c->name);
+ if (!shrink)
+ goto err;
+ bc->shrink = shrink;
+ shrink->count_objects = bch2_btree_cache_count;
+ shrink->scan_objects = bch2_btree_cache_scan;
+ shrink->seeks = 4;
+ shrink->private_data = c;
+ shrinker_register(shrink);
+
+ return 0;
+err:
+ return -BCH_ERR_ENOMEM_fs_btree_cache_init;
+}
+
+void bch2_fs_btree_cache_init_early(struct btree_cache *bc)
+{
+ mutex_init(&bc->lock);
+ INIT_LIST_HEAD(&bc->live);
+ INIT_LIST_HEAD(&bc->freeable);
+ INIT_LIST_HEAD(&bc->freed_pcpu);
+ INIT_LIST_HEAD(&bc->freed_nonpcpu);
+}
+
+/*
+ * We can only have one thread cannibalizing other cached btree nodes at a time,
+ * or we'll deadlock. We use an open coded mutex to ensure that, which a
+ * cannibalize_bucket() will take. This means every time we unlock the root of
+ * the btree, we need to release this lock if we have it held.
+ */
+void bch2_btree_cache_cannibalize_unlock(struct btree_trans *trans)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+
+ if (bc->alloc_lock == current) {
+ trace_and_count(c, btree_cache_cannibalize_unlock, trans);
+ bc->alloc_lock = NULL;
+ closure_wake_up(&bc->alloc_wait);
+ }
+}
+
+int bch2_btree_cache_cannibalize_lock(struct btree_trans *trans, struct closure *cl)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+ struct task_struct *old;
+
+ old = cmpxchg(&bc->alloc_lock, NULL, current);
+ if (old == NULL || old == current)
+ goto success;
+
+ if (!cl) {
+ trace_and_count(c, btree_cache_cannibalize_lock_fail, trans);
+ return -BCH_ERR_ENOMEM_btree_cache_cannibalize_lock;
+ }
+
+ closure_wait(&bc->alloc_wait, cl);
+
+ /* Try again, after adding ourselves to waitlist */
+ old = cmpxchg(&bc->alloc_lock, NULL, current);
+ if (old == NULL || old == current) {
+ /* We raced */
+ closure_wake_up(&bc->alloc_wait);
+ goto success;
+ }
+
+ trace_and_count(c, btree_cache_cannibalize_lock_fail, trans);
+ return -BCH_ERR_btree_cache_cannibalize_lock_blocked;
+
+success:
+ trace_and_count(c, btree_cache_cannibalize_lock, trans);
+ return 0;
+}
+
+static struct btree *btree_node_cannibalize(struct bch_fs *c)
+{
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+
+ list_for_each_entry_reverse(b, &bc->live, list)
+ if (!btree_node_reclaim(c, b))
+ return b;
+
+ while (1) {
+ list_for_each_entry_reverse(b, &bc->live, list)
+ if (!btree_node_write_and_reclaim(c, b))
+ return b;
+
+ /*
+ * Rare case: all nodes were intent-locked.
+ * Just busy-wait.
+ */
+ WARN_ONCE(1, "btree cache cannibalize failed\n");
+ cond_resched();
+ }
+}
+
+struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_read_locks)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+ struct list_head *freed = pcpu_read_locks
+ ? &bc->freed_pcpu
+ : &bc->freed_nonpcpu;
+ struct btree *b, *b2;
+ u64 start_time = local_clock();
+ unsigned flags;
+
+ flags = memalloc_nofs_save();
+ mutex_lock(&bc->lock);
+
+ /*
+ * We never free struct btree itself, just the memory that holds the on
+ * disk node. Check the freed list before allocating a new one:
+ */
+ list_for_each_entry(b, freed, list)
+ if (!btree_node_reclaim(c, b)) {
+ list_del_init(&b->list);
+ goto got_node;
+ }
+
+ b = __btree_node_mem_alloc(c, GFP_NOWAIT|__GFP_NOWARN);
+ if (!b) {
+ mutex_unlock(&bc->lock);
+ bch2_trans_unlock(trans);
+ b = __btree_node_mem_alloc(c, GFP_KERNEL);
+ if (!b)
+ goto err;
+ mutex_lock(&bc->lock);
+ }
+
+ bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0);
+
+ BUG_ON(!six_trylock_intent(&b->c.lock));
+ BUG_ON(!six_trylock_write(&b->c.lock));
+got_node:
+
+ /*
+ * btree_free() doesn't free memory; it sticks the node on the end of
+ * the list. Check if there's any freed nodes there:
+ */
+ list_for_each_entry(b2, &bc->freeable, list)
+ if (!btree_node_reclaim(c, b2)) {
+ swap(b->data, b2->data);
+ swap(b->aux_data, b2->aux_data);
+ btree_node_to_freedlist(bc, b2);
+ six_unlock_write(&b2->c.lock);
+ six_unlock_intent(&b2->c.lock);
+ goto got_mem;
+ }
+
+ mutex_unlock(&bc->lock);
+
+ if (btree_node_data_alloc(c, b, GFP_NOWAIT|__GFP_NOWARN)) {
+ bch2_trans_unlock(trans);
+ if (btree_node_data_alloc(c, b, GFP_KERNEL|__GFP_NOWARN))
+ goto err;
+ }
+
+ mutex_lock(&bc->lock);
+ bc->used++;
+got_mem:
+ mutex_unlock(&bc->lock);
+
+ BUG_ON(btree_node_hashed(b));
+ BUG_ON(btree_node_dirty(b));
+ BUG_ON(btree_node_write_in_flight(b));
+out:
+ b->flags = 0;
+ b->written = 0;
+ b->nsets = 0;
+ b->sib_u64s[0] = 0;
+ b->sib_u64s[1] = 0;
+ b->whiteout_u64s = 0;
+ bch2_btree_keys_init(b);
+ set_btree_node_accessed(b);
+
+ bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],
+ start_time);
+
+ memalloc_nofs_restore(flags);
+ return b;
+err:
+ mutex_lock(&bc->lock);
+
+ /* Try to cannibalize another cached btree node: */
+ if (bc->alloc_lock == current) {
+ b2 = btree_node_cannibalize(c);
+ clear_btree_node_just_written(b2);
+ bch2_btree_node_hash_remove(bc, b2);
+
+ if (b) {
+ swap(b->data, b2->data);
+ swap(b->aux_data, b2->aux_data);
+ btree_node_to_freedlist(bc, b2);
+ six_unlock_write(&b2->c.lock);
+ six_unlock_intent(&b2->c.lock);
+ } else {
+ b = b2;
+ list_del_init(&b->list);
+ }
+
+ mutex_unlock(&bc->lock);
+
+ trace_and_count(c, btree_cache_cannibalize, trans);
+ goto out;
+ }
+
+ mutex_unlock(&bc->lock);
+ memalloc_nofs_restore(flags);
+ return ERR_PTR(-BCH_ERR_ENOMEM_btree_node_mem_alloc);
+}
+
+/* Slowpath, don't want it inlined into btree_iter_traverse() */
+static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans,
+ struct btree_path *path,
+ const struct bkey_i *k,
+ enum btree_id btree_id,
+ unsigned level,
+ enum six_lock_type lock_type,
+ bool sync)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+ u32 seq;
+
+ BUG_ON(level + 1 >= BTREE_MAX_DEPTH);
+ /*
+ * Parent node must be locked, else we could read in a btree node that's
+ * been freed:
+ */
+ if (path && !bch2_btree_node_relock(trans, path, level + 1)) {
+ trace_and_count(c, trans_restart_relock_parent_for_fill, trans, _THIS_IP_, path);
+ return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_relock));
+ }
+
+ b = bch2_btree_node_mem_alloc(trans, level != 0);
+
+ if (bch2_err_matches(PTR_ERR_OR_ZERO(b), ENOMEM)) {
+ trans->memory_allocation_failure = true;
+ trace_and_count(c, trans_restart_memory_allocation_failure, trans, _THIS_IP_, path);
+ return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_mem_alloc_fail));
+ }
+
+ if (IS_ERR(b))
+ return b;
+
+ bkey_copy(&b->key, k);
+ if (bch2_btree_node_hash_insert(bc, b, level, btree_id)) {
+ /* raced with another fill: */
+
+ /* mark as unhashed... */
+ b->hash_val = 0;
+
+ mutex_lock(&bc->lock);
+ list_add(&b->list, &bc->freeable);
+ mutex_unlock(&bc->lock);
+
+ six_unlock_write(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+ return NULL;
+ }
+
+ set_btree_node_read_in_flight(b);
+
+ six_unlock_write(&b->c.lock);
+ seq = six_lock_seq(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+
+ /* Unlock before doing IO: */
+ if (path && sync)
+ bch2_trans_unlock_noassert(trans);
+
+ bch2_btree_node_read(trans, b, sync);
+
+ if (!sync)
+ return NULL;
+
+ if (path) {
+ int ret = bch2_trans_relock(trans) ?:
+ bch2_btree_path_relock_intent(trans, path);
+ if (ret) {
+ BUG_ON(!trans->restarted);
+ return ERR_PTR(ret);
+ }
+ }
+
+ if (!six_relock_type(&b->c.lock, lock_type, seq)) {
+ if (path)
+ trace_and_count(c, trans_restart_relock_after_fill, trans, _THIS_IP_, path);
+ return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_relock_after_fill));
+ }
+
+ return b;
+}
+
+static noinline void btree_bad_header(struct bch_fs *c, struct btree *b)
+{
+ struct printbuf buf = PRINTBUF;
+
+ if (c->curr_recovery_pass <= BCH_RECOVERY_PASS_check_allocations)
+ return;
+
+ prt_printf(&buf,
+ "btree node header doesn't match ptr\n"
+ "btree %s level %u\n"
+ "ptr: ",
+ bch2_btree_id_str(b->c.btree_id), b->c.level);
+ bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
+
+ prt_printf(&buf, "\nheader: btree %s level %llu\n"
+ "min ",
+ bch2_btree_id_str(BTREE_NODE_ID(b->data)),
+ BTREE_NODE_LEVEL(b->data));
+ bch2_bpos_to_text(&buf, b->data->min_key);
+
+ prt_printf(&buf, "\nmax ");
+ bch2_bpos_to_text(&buf, b->data->max_key);
+
+ bch2_fs_inconsistent(c, "%s", buf.buf);
+ printbuf_exit(&buf);
+}
+
+static inline void btree_check_header(struct bch_fs *c, struct btree *b)
+{
+ if (b->c.btree_id != BTREE_NODE_ID(b->data) ||
+ b->c.level != BTREE_NODE_LEVEL(b->data) ||
+ !bpos_eq(b->data->max_key, b->key.k.p) ||
+ (b->key.k.type == KEY_TYPE_btree_ptr_v2 &&
+ !bpos_eq(b->data->min_key,
+ bkey_i_to_btree_ptr_v2(&b->key)->v.min_key)))
+ btree_bad_header(c, b);
+}
+
+static struct btree *__bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
+ const struct bkey_i *k, unsigned level,
+ enum six_lock_type lock_type,
+ unsigned long trace_ip)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+ struct bset_tree *t;
+ bool need_relock = false;
+ int ret;
+
+ EBUG_ON(level >= BTREE_MAX_DEPTH);
+retry:
+ b = btree_cache_find(bc, k);
+ if (unlikely(!b)) {
+ /*
+ * We must have the parent locked to call bch2_btree_node_fill(),
+ * else we could read in a btree node from disk that's been
+ * freed:
+ */
+ b = bch2_btree_node_fill(trans, path, k, path->btree_id,
+ level, lock_type, true);
+ need_relock = true;
+
+ /* We raced and found the btree node in the cache */
+ if (!b)
+ goto retry;
+
+ if (IS_ERR(b))
+ return b;
+ } else {
+ if (btree_node_read_locked(path, level + 1))
+ btree_node_unlock(trans, path, level + 1);
+
+ ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
+ if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+ return ERR_PTR(ret);
+
+ BUG_ON(ret);
+
+ if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
+ b->c.level != level ||
+ race_fault())) {
+ six_unlock_type(&b->c.lock, lock_type);
+ if (bch2_btree_node_relock(trans, path, level + 1))
+ goto retry;
+
+ trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
+ return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
+ }
+
+ /* avoid atomic set bit if it's not needed: */
+ if (!btree_node_accessed(b))
+ set_btree_node_accessed(b);
+ }
+
+ if (unlikely(btree_node_read_in_flight(b))) {
+ u32 seq = six_lock_seq(&b->c.lock);
+
+ six_unlock_type(&b->c.lock, lock_type);
+ bch2_trans_unlock(trans);
+ need_relock = true;
+
+ bch2_btree_node_wait_on_read(b);
+
+ /*
+ * should_be_locked is not set on this path yet, so we need to
+ * relock it specifically:
+ */
+ if (!six_relock_type(&b->c.lock, lock_type, seq))
+ goto retry;
+ }
+
+ if (unlikely(need_relock)) {
+ ret = bch2_trans_relock(trans) ?:
+ bch2_btree_path_relock_intent(trans, path);
+ if (ret) {
+ six_unlock_type(&b->c.lock, lock_type);
+ return ERR_PTR(ret);
+ }
+ }
+
+ prefetch(b->aux_data);
+
+ for_each_bset(b, t) {
+ void *p = (u64 *) b->aux_data + t->aux_data_offset;
+
+ prefetch(p + L1_CACHE_BYTES * 0);
+ prefetch(p + L1_CACHE_BYTES * 1);
+ prefetch(p + L1_CACHE_BYTES * 2);
+ }
+
+ if (unlikely(btree_node_read_error(b))) {
+ six_unlock_type(&b->c.lock, lock_type);
+ return ERR_PTR(-EIO);
+ }
+
+ EBUG_ON(b->c.btree_id != path->btree_id);
+ EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
+ btree_check_header(c, b);
+
+ return b;
+}
+
+/**
+ * bch2_btree_node_get - find a btree node in the cache and lock it, reading it
+ * in from disk if necessary.
+ *
+ * @trans: btree transaction object
+ * @path: btree_path being traversed
+ * @k: pointer to btree node (generally KEY_TYPE_btree_ptr_v2)
+ * @level: level of btree node being looked up (0 == leaf node)
+ * @lock_type: SIX_LOCK_read or SIX_LOCK_intent
+ * @trace_ip: ip of caller of btree iterator code (i.e. caller of bch2_btree_iter_peek())
+ *
+ * The btree node will have either a read or a write lock held, depending on
+ * the @write parameter.
+ *
+ * Returns: btree node or ERR_PTR()
+ */
+struct btree *bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
+ const struct bkey_i *k, unsigned level,
+ enum six_lock_type lock_type,
+ unsigned long trace_ip)
+{
+ struct bch_fs *c = trans->c;
+ struct btree *b;
+ struct bset_tree *t;
+ int ret;
+
+ EBUG_ON(level >= BTREE_MAX_DEPTH);
+
+ b = btree_node_mem_ptr(k);
+
+ /*
+ * Check b->hash_val _before_ calling btree_node_lock() - this might not
+ * be the node we want anymore, and trying to lock the wrong node could
+ * cause an unneccessary transaction restart:
+ */
+ if (unlikely(!c->opts.btree_node_mem_ptr_optimization ||
+ !b ||
+ b->hash_val != btree_ptr_hash_val(k)))
+ return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
+
+ if (btree_node_read_locked(path, level + 1))
+ btree_node_unlock(trans, path, level + 1);
+
+ ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
+ if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+ return ERR_PTR(ret);
+
+ BUG_ON(ret);
+
+ if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
+ b->c.level != level ||
+ race_fault())) {
+ six_unlock_type(&b->c.lock, lock_type);
+ if (bch2_btree_node_relock(trans, path, level + 1))
+ return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
+
+ trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
+ return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
+ }
+
+ if (unlikely(btree_node_read_in_flight(b))) {
+ six_unlock_type(&b->c.lock, lock_type);
+ return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
+ }
+
+ prefetch(b->aux_data);
+
+ for_each_bset(b, t) {
+ void *p = (u64 *) b->aux_data + t->aux_data_offset;
+
+ prefetch(p + L1_CACHE_BYTES * 0);
+ prefetch(p + L1_CACHE_BYTES * 1);
+ prefetch(p + L1_CACHE_BYTES * 2);
+ }
+
+ /* avoid atomic set bit if it's not needed: */
+ if (!btree_node_accessed(b))
+ set_btree_node_accessed(b);
+
+ if (unlikely(btree_node_read_error(b))) {
+ six_unlock_type(&b->c.lock, lock_type);
+ return ERR_PTR(-EIO);
+ }
+
+ EBUG_ON(b->c.btree_id != path->btree_id);
+ EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
+ btree_check_header(c, b);
+
+ return b;
+}
+
+struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans,
+ const struct bkey_i *k,
+ enum btree_id btree_id,
+ unsigned level,
+ bool nofill)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+ struct bset_tree *t;
+ int ret;
+
+ EBUG_ON(level >= BTREE_MAX_DEPTH);
+
+ if (c->opts.btree_node_mem_ptr_optimization) {
+ b = btree_node_mem_ptr(k);
+ if (b)
+ goto lock_node;
+ }
+retry:
+ b = btree_cache_find(bc, k);
+ if (unlikely(!b)) {
+ if (nofill)
+ goto out;
+
+ b = bch2_btree_node_fill(trans, NULL, k, btree_id,
+ level, SIX_LOCK_read, true);
+
+ /* We raced and found the btree node in the cache */
+ if (!b)
+ goto retry;
+
+ if (IS_ERR(b) &&
+ !bch2_btree_cache_cannibalize_lock(trans, NULL))
+ goto retry;
+
+ if (IS_ERR(b))
+ goto out;
+ } else {
+lock_node:
+ ret = btree_node_lock_nopath(trans, &b->c, SIX_LOCK_read, _THIS_IP_);
+ if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
+ return ERR_PTR(ret);
+
+ BUG_ON(ret);
+
+ if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
+ b->c.btree_id != btree_id ||
+ b->c.level != level)) {
+ six_unlock_read(&b->c.lock);
+ goto retry;
+ }
+ }
+
+ /* XXX: waiting on IO with btree locks held: */
+ __bch2_btree_node_wait_on_read(b);
+
+ prefetch(b->aux_data);
+
+ for_each_bset(b, t) {
+ void *p = (u64 *) b->aux_data + t->aux_data_offset;
+
+ prefetch(p + L1_CACHE_BYTES * 0);
+ prefetch(p + L1_CACHE_BYTES * 1);
+ prefetch(p + L1_CACHE_BYTES * 2);
+ }
+
+ /* avoid atomic set bit if it's not needed: */
+ if (!btree_node_accessed(b))
+ set_btree_node_accessed(b);
+
+ if (unlikely(btree_node_read_error(b))) {
+ six_unlock_read(&b->c.lock);
+ b = ERR_PTR(-EIO);
+ goto out;
+ }
+
+ EBUG_ON(b->c.btree_id != btree_id);
+ EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
+ btree_check_header(c, b);
+out:
+ bch2_btree_cache_cannibalize_unlock(trans);
+ return b;
+}
+
+int bch2_btree_node_prefetch(struct btree_trans *trans,
+ struct btree_path *path,
+ const struct bkey_i *k,
+ enum btree_id btree_id, unsigned level)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+
+ BUG_ON(trans && !btree_node_locked(path, level + 1));
+ BUG_ON(level >= BTREE_MAX_DEPTH);
+
+ b = btree_cache_find(bc, k);
+ if (b)
+ return 0;
+
+ b = bch2_btree_node_fill(trans, path, k, btree_id,
+ level, SIX_LOCK_read, false);
+ return PTR_ERR_OR_ZERO(b);
+}
+
+void bch2_btree_node_evict(struct btree_trans *trans, const struct bkey_i *k)
+{
+ struct bch_fs *c = trans->c;
+ struct btree_cache *bc = &c->btree_cache;
+ struct btree *b;
+
+ b = btree_cache_find(bc, k);
+ if (!b)
+ return;
+wait_on_io:
+ /* not allowed to wait on io with btree locks held: */
+
+ /* XXX we're called from btree_gc which will be holding other btree
+ * nodes locked
+ */
+ __bch2_btree_node_wait_on_read(b);
+ __bch2_btree_node_wait_on_write(b);
+
+ btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
+ btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
+
+ if (btree_node_dirty(b)) {
+ __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
+ six_unlock_write(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+ goto wait_on_io;
+ }
+
+ BUG_ON(btree_node_dirty(b));
+
+ mutex_lock(&bc->lock);
+ btree_node_data_free(c, b);
+ bch2_btree_node_hash_remove(bc, b);
+ mutex_unlock(&bc->lock);
+
+ six_unlock_write(&b->c.lock);
+ six_unlock_intent(&b->c.lock);
+}
+
+const char *bch2_btree_id_str(enum btree_id btree)
+{
+ return btree < BTREE_ID_NR ? __bch2_btree_ids[btree] : "(unknown)";
+}
+
+void bch2_btree_pos_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
+{
+ prt_printf(out, "%s level %u/%u\n ",
+ bch2_btree_id_str(b->c.btree_id),
+ b->c.level,
+ bch2_btree_id_root(c, b->c.btree_id)->level);
+ bch2_bkey_val_to_text(out, c, bkey_i_to_s_c(&b->key));
+}
+
+void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
+{
+ struct bset_stats stats;
+
+ memset(&stats, 0, sizeof(stats));
+
+ bch2_btree_keys_stats(b, &stats);
+
+ prt_printf(out, "l %u ", b->c.level);
+ bch2_bpos_to_text(out, b->data->min_key);
+ prt_printf(out, " - ");
+ bch2_bpos_to_text(out, b->data->max_key);
+ prt_printf(out, ":\n"
+ " ptrs: ");
+ bch2_val_to_text(out, c, bkey_i_to_s_c(&b->key));
+ prt_newline(out);
+
+ prt_printf(out,
+ " format: ");
+ bch2_bkey_format_to_text(out, &b->format);
+
+ prt_printf(out,
+ " unpack fn len: %u\n"
+ " bytes used %zu/%zu (%zu%% full)\n"
+ " sib u64s: %u, %u (merge threshold %u)\n"
+ " nr packed keys %u\n"
+ " nr unpacked keys %u\n"
+ " floats %zu\n"
+ " failed unpacked %zu\n",
+ b->unpack_fn_len,
+ b->nr.live_u64s * sizeof(u64),
+ btree_bytes(c) - sizeof(struct btree_node),
+ b->nr.live_u64s * 100 / btree_max_u64s(c),
+ b->sib_u64s[0],
+ b->sib_u64s[1],
+ c->btree_foreground_merge_threshold,
+ b->nr.packed_keys,
+ b->nr.unpacked_keys,
+ stats.floats,
+ stats.failed);
+}
+
+void bch2_btree_cache_to_text(struct printbuf *out, const struct bch_fs *c)
+{
+ prt_printf(out, "nr nodes:\t\t%u\n", c->btree_cache.used);
+ prt_printf(out, "nr dirty:\t\t%u\n", atomic_read(&c->btree_cache.dirty));
+ prt_printf(out, "cannibalize lock:\t%p\n", c->btree_cache.alloc_lock);
+}
projects / bcachefs-tools-debian / blobdiff