bcachefs: Refactor filesystem usage accounting

Various filesystem usage counters are kept in percpu counters, with one
set per in flight journal buffer. Right now all the code that deals with
it assumes that there's only two buffers/sets of counters, but the
number of journal bufs is getting increased to 4 in the next patch - so
refactor that code to not assume a constant.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 17 insertions, 13 deletions

diff --git a/fs/bcachefs/replicas.c b/fs/bcachefs/replicas.c
index f46aa1d70e35..85c97f67936a 100644
--- a/fs/bcachefs/replicas.c
+++ b/fs/bcachefs/replicas.c
@@ -275,7 +275,7 @@ static void __replicas_table_update_pcpu(struct bch_fs_usage __percpu *dst_p,
 static int replicas_table_update(struct bch_fs *c,
 				 struct bch_replicas_cpu *new_r)
 {
-	struct bch_fs_usage __percpu *new_usage[2];
+	struct bch_fs_usage __percpu *new_usage[JOURNAL_BUF_NR];
 	struct bch_fs_usage_online *new_scratch = NULL;
 	struct bch_fs_usage __percpu *new_gc = NULL;
 	struct bch_fs_usage *new_base = NULL;
@@ -283,7 +283,14 @@ static int replicas_table_update(struct bch_fs *c,
 		sizeof(u64) * new_r->nr;
 	unsigned scratch_bytes = sizeof(struct bch_fs_usage_online) +
 		sizeof(u64) * new_r->nr;
-	int ret = -ENOMEM;
+	int ret = 0;
+
+	memset(new_usage, 0, sizeof(new_usage));
+
+	for (i = 0; i < ARRAY_SIZE(new_usage); i++)
+		if (!(new_usage[i] = __alloc_percpu_gfp(bytes,
+					sizeof(u64), GFP_NOIO)))
+			goto err;
 
 	memset(new_usage, 0, sizeof(new_usage));
 
@@ -295,10 +302,8 @@ static int replicas_table_update(struct bch_fs *c,
 	if (!(new_base = kzalloc(bytes, GFP_NOIO)) ||
 	    !(new_scratch  = kmalloc(scratch_bytes, GFP_NOIO)) ||
 	    (c->usage_gc &&
-	     !(new_gc = __alloc_percpu_gfp(bytes, sizeof(u64), GFP_NOIO)))) {
-		bch_err(c, "error updating replicas table: memory allocation failure");
+	     !(new_gc = __alloc_percpu_gfp(bytes, sizeof(u64), GFP_NOIO))))
 		goto err;
-	}
 
 	for (i = 0; i < ARRAY_SIZE(new_usage); i++)
 		if (c->usage[i])
@@ -317,14 +322,17 @@ static int replicas_table_update(struct bch_fs *c,
 	swap(c->usage_scratch,	new_scratch);
 	swap(c->usage_gc,	new_gc);
 	swap(c->replicas,	*new_r);
-	ret = 0;
-err:
+out:
 	free_percpu(new_gc);
 	kfree(new_scratch);
 	free_percpu(new_usage[1]);
 	free_percpu(new_usage[0]);
 	kfree(new_base);
 	return ret;
+err:
+	bch_err(c, "error updating replicas table: memory allocation failure");
+	ret = -ENOMEM;
+	goto out;
 }
 
 static unsigned reserve_journal_replicas(struct bch_fs *c,
@@ -499,9 +507,7 @@ int bch2_replicas_gc_end(struct bch_fs *c, int ret)
 		struct bch_replicas_cpu n;
 
 		if (!__replicas_has_entry(&c->replicas_gc, e) &&
-		    (c->usage_base->replicas[i] ||
-		     percpu_u64_get(&c->usage[0]->replicas[i]) ||
-		     percpu_u64_get(&c->usage[1]->replicas[i]))) {
+		    bch2_fs_usage_read_one(c, &c->usage_base->replicas[i])) {
 			n = cpu_replicas_add_entry(&c->replicas_gc, e);
 			if (!n.entries) {
 				ret = -ENOSPC;
@@ -606,9 +612,7 @@ retry:
 			cpu_replicas_entry(&c->replicas, i);
 
 		if (e->data_type == BCH_DATA_journal ||
-		    c->usage_base->replicas[i] ||
-		    percpu_u64_get(&c->usage[0]->replicas[i]) ||
-		    percpu_u64_get(&c->usage[1]->replicas[i]))
+		    bch2_fs_usage_read_one(c, &c->usage_base->replicas[i]))
 			memcpy(cpu_replicas_entry(&new, new.nr++),
 			       e, new.entry_size);
 	}