Merge tag 'bcachefs-2023-11-17' of https://evilpiepirate.org/git/bcachefs

Pull bcachefs fixes from Kent Overstreet:
 "Lots of small fixes for minor nits and compiler warnings.

  Bigger items:

   - The six locks lost wakeup is finally fixed: six_read_trylock() was
     checking for the waiting bit before decrementing the number of
     readers - validated the fix with a torture test.

   - Fix for a memory reclaim issue: when needing to reallocate a key
     cache key, we now do our usual GFP_NOWAIT; unlock(); GFP_KERNEL
     dance.

   - Multiple deleted inodes btree fixes

   - Fix an issue in fsck, where i_nlink would be recalculated
     incorrectly for hardlinked files if a snapshot had ever been taken.

   - Kill journal pre-reservations: This is a bigger patch than I would
     normally send at this point, but it deletes code and it fixes some
     of our tests that would sporadically die with the journal getting
     stuck, and it's a performance improvement, too"

* tag 'bcachefs-2023-11-17' of https://evilpiepirate.org/git/bcachefs: (22 commits)
  bcachefs: Fix missing locking for dentry->d_parent access
  bcachefs: six locks: Fix lost wakeup
  bcachefs: Fix no_data_io mode checksum check
  bcachefs: Fix bch2_check_nlinks() for snapshots
  bcachefs: Don't decrease BTREE_ITER_MAX when LOCKDEP=y
  bcachefs: Disable debug log statements
  bcachefs: Fix missing transaction commit
  bcachefs: Fix error path in bch2_mount()
  bcachefs: Fix potential sleeping during mount
  bcachefs: Fix iterator leak in may_delete_deleted_inode()
  bcachefs: Kill journal pre-reservations
  bcachefs: Check for nonce offset inconsistency in data_update path
  bcachefs: Make sure to drop/retake btree locks before reclaim
  bcachefs: btree_trans->write_locked
  bcachefs: Run btree key cache shrinker less aggressively
  bcachefs: Split out btree_key_cache_types.h
  bcachefs: Guard against insufficient devices to create stripes
  bcachefs: Fix null ptr deref in bch2_backpointer_get_node()
  bcachefs: Fix multiple -Warray-bounds warnings
  bcachefs: Use DECLARE_FLEX_ARRAY() helper and fix multiple -Warray-bounds warnings
  ...

Author: torvalds

fs/bcachefs/backpointers.c

@@ -313,17 +313,17 @@ struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 				  bp.level - 1,
 				  0);
 	b = bch2_btree_iter_peek_node(iter);
-	if (IS_ERR(b))
+	if (IS_ERR_OR_NULL(b))
 		goto err;
 
 	BUG_ON(b->c.level != bp.level - 1);
 
-	if (b && extent_matches_bp(c, bp.btree_id, bp.level,
-				   bkey_i_to_s_c(&b->key),
-				   bucket, bp))
+	if (extent_matches_bp(c, bp.btree_id, bp.level,
+			      bkey_i_to_s_c(&b->key),
+			      bucket, bp))
 		return b;
 
-	if (b && btree_node_will_make_reachable(b)) {
+	if (btree_node_will_make_reachable(b)) {
 		b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
 	} else {
 		backpointer_not_found(trans, bp_pos, bp, bkey_i_to_s_c(&b->key));

fs/bcachefs/bcachefs.h

@@ -617,7 +617,7 @@ struct journal_seq_blacklist_table {
 		u64		start;
 		u64		end;
 		bool		dirty;
-	}			entries[0];
+	}			entries[];
 };
 
 struct journal_keys {

fs/bcachefs/btree_iter.c

@@ -3087,8 +3087,6 @@ void bch2_trans_put(struct btree_trans *trans)
 		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) {

fs/bcachefs/btree_key_cache.c

@@ -89,10 +89,13 @@ static void bkey_cached_free(struct btree_key_cache *bc,
 	ck->btree_trans_barrier_seq =
 		start_poll_synchronize_srcu(&c->btree_trans_barrier);
 
-	if (ck->c.lock.readers)
+	if (ck->c.lock.readers) {
 		list_move_tail(&ck->list, &bc->freed_pcpu);
-	else
+		bc->nr_freed_pcpu++;
+	} else {
 		list_move_tail(&ck->list, &bc->freed_nonpcpu);
+		bc->nr_freed_nonpcpu++;
+	}
 	atomic_long_inc(&bc->nr_freed);
 
 	kfree(ck->k);
@@ -109,6 +112,8 @@ static void __bkey_cached_move_to_freelist_ordered(struct btree_key_cache *bc,
 {
 	struct bkey_cached *pos;
 
+	bc->nr_freed_nonpcpu++;
+
 	list_for_each_entry_reverse(pos, &bc->freed_nonpcpu, list) {
 		if (ULONG_CMP_GE(ck->btree_trans_barrier_seq,
 				 pos->btree_trans_barrier_seq)) {
@@ -158,6 +163,7 @@ static void bkey_cached_move_to_freelist(struct btree_key_cache *bc,
 #else
 		mutex_lock(&bc->lock);
 		list_move_tail(&ck->list, &bc->freed_nonpcpu);
+		bc->nr_freed_nonpcpu++;
 		mutex_unlock(&bc->lock);
 #endif
 	} else {
@@ -217,6 +223,7 @@ bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path,
 			       f->nr < ARRAY_SIZE(f->objs) / 2) {
 				ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
 				list_del_init(&ck->list);
+				bc->nr_freed_nonpcpu--;
 				f->objs[f->nr++] = ck;
 			}
 
@@ -229,6 +236,7 @@ bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path,
 		if (!list_empty(&bc->freed_nonpcpu)) {
 			ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
 			list_del_init(&ck->list);
+			bc->nr_freed_nonpcpu--;
 		}
 		mutex_unlock(&bc->lock);
 #endif
@@ -664,7 +672,6 @@ static int btree_key_cache_flush_pos(struct btree_trans *trans,
 		goto out;
 
 	bch2_journal_pin_drop(j, &ck->journal);
-	bch2_journal_preres_put(j, &ck->res);
 
 	BUG_ON(!btree_node_locked(c_iter.path, 0));
 
@@ -762,18 +769,6 @@ bool bch2_btree_insert_key_cached(struct btree_trans *trans,
 
 	BUG_ON(insert->k.u64s > ck->u64s);
 
-	if (likely(!(flags & BTREE_INSERT_JOURNAL_REPLAY))) {
-		int difference;
-
-		BUG_ON(jset_u64s(insert->k.u64s) > trans->journal_preres.u64s);
-
-		difference = jset_u64s(insert->k.u64s) - ck->res.u64s;
-		if (difference > 0) {
-			trans->journal_preres.u64s	-= difference;
-			ck->res.u64s			+= difference;
-		}
-	}
-
 	bkey_copy(ck->k, insert);
 	ck->valid = true;
 
@@ -850,6 +845,8 @@ static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 	 * Newest freed entries are at the end of the list - once we hit one
 	 * that's too new to be freed, we can bail out:
 	 */
+	scanned += bc->nr_freed_nonpcpu;
+
 	list_for_each_entry_safe(ck, t, &bc->freed_nonpcpu, list) {
 		if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
 						 ck->btree_trans_barrier_seq))
@@ -859,13 +856,15 @@ static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 		six_lock_exit(&ck->c.lock);
 		kmem_cache_free(bch2_key_cache, ck);
 		atomic_long_dec(&bc->nr_freed);
-		scanned++;
 		freed++;
+		bc->nr_freed_nonpcpu--;
 	}
 
 	if (scanned >= nr)
 		goto out;
 
+	scanned += bc->nr_freed_pcpu;
+
 	list_for_each_entry_safe(ck, t, &bc->freed_pcpu, list) {
 		if (!poll_state_synchronize_srcu(&c->btree_trans_barrier,
 						 ck->btree_trans_barrier_seq))
@@ -875,8 +874,8 @@ static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 		six_lock_exit(&ck->c.lock);
 		kmem_cache_free(bch2_key_cache, ck);
 		atomic_long_dec(&bc->nr_freed);
-		scanned++;
 		freed++;
+		bc->nr_freed_pcpu--;
 	}
 
 	if (scanned >= nr)
@@ -982,6 +981,9 @@ void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 	}
 #endif
 
+	BUG_ON(list_count_nodes(&bc->freed_pcpu) != bc->nr_freed_pcpu);
+	BUG_ON(list_count_nodes(&bc->freed_nonpcpu) != bc->nr_freed_nonpcpu);
+
 	list_splice(&bc->freed_pcpu,	&items);
 	list_splice(&bc->freed_nonpcpu,	&items);
 
@@ -991,7 +993,6 @@ void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 		cond_resched();
 
 		bch2_journal_pin_drop(&c->journal, &ck->journal);
-		bch2_journal_preres_put(&c->journal, &ck->res);
 
 		list_del(&ck->list);
 		kfree(ck->k);

fs/bcachefs/btree_key_cache_types.h

@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_BTREE_KEY_CACHE_TYPES_H
+#define _BCACHEFS_BTREE_KEY_CACHE_TYPES_H
+
+struct btree_key_cache_freelist {
+	struct bkey_cached	*objs[16];
+	unsigned		nr;
+};
+
+struct btree_key_cache {
+	struct mutex		lock;
+	struct rhashtable	table;
+	bool			table_init_done;
+
+	struct list_head	freed_pcpu;
+	size_t			nr_freed_pcpu;
+	struct list_head	freed_nonpcpu;
+	size_t			nr_freed_nonpcpu;
+
+	struct shrinker		*shrink;
+	unsigned		shrink_iter;
+	struct btree_key_cache_freelist __percpu *pcpu_freed;
+
+	atomic_long_t		nr_freed;
+	atomic_long_t		nr_keys;
+	atomic_long_t		nr_dirty;
+};
+
+struct bkey_cached_key {
+	u32			btree_id;
+	struct bpos		pos;
+} __packed __aligned(4);
+
+#endif /* _BCACHEFS_BTREE_KEY_CACHE_TYPES_H */