bcachefs: bkey noops

For upcoming inline data extents, we're going to need to be able to
shorten the value of existing bkeys in the btree - and to make that work
we're going to be able to need to pad out the space the value previously
took up with something.

This patch changes the various code that iterates over bkeys to handle
k->u64s == 0 as meaning "skip the next 8 bytes".

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

1 files changed, 22 insertions, 31 deletions

diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index 591980d2011f..c345262d804b 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -26,34 +26,33 @@ static void verify_no_dups(struct btree *b,
 			   struct bkey_packed *end)
 {
 #ifdef CONFIG_BCACHEFS_DEBUG
-	struct bkey_packed *k;
+	struct bkey_packed *k, *p;
+
+	if (start == end)
+		return;
 
-	for (k = start; k != end && bkey_next(k) != end; k = bkey_next(k)) {
-		struct bkey l = bkey_unpack_key(b, k);
-		struct bkey r = bkey_unpack_key(b, bkey_next(k));
+	for (p = start, k = bkey_next_skip_noops(start, end);
+	     k != end;
+	     p = k, k = bkey_next_skip_noops(k, end)) {
+		struct bkey l = bkey_unpack_key(b, p);
+		struct bkey r = bkey_unpack_key(b, k);
 
 		BUG_ON(btree_node_is_extents(b)
 		       ? bkey_cmp(l.p, bkey_start_pos(&r)) > 0
 		       : bkey_cmp(l.p, bkey_start_pos(&r)) >= 0);
-		//BUG_ON(bkey_cmp_packed(&b->format, k, bkey_next(k)) >= 0);
+		//BUG_ON(bkey_cmp_packed(&b->format, p, k) >= 0);
 	}
 #endif
 }
 
-static void clear_needs_whiteout(struct bset *i)
-{
-	struct bkey_packed *k;
-
-	for (k = i->start; k != vstruct_last(i); k = bkey_next(k))
-		k->needs_whiteout = false;
-}
-
-static void set_needs_whiteout(struct bset *i)
+static void set_needs_whiteout(struct bset *i, int v)
 {
 	struct bkey_packed *k;
 
-	for (k = i->start; k != vstruct_last(i); k = bkey_next(k))
-		k->needs_whiteout = true;
+	for (k = i->start;
+	     k != vstruct_last(i);
+	     k = bkey_next_skip_noops(k, vstruct_last(i)))
+		k->needs_whiteout = v;
 }
 
 static void btree_bounce_free(struct bch_fs *c, unsigned order,
@@ -168,7 +167,7 @@ bool __bch2_compact_whiteouts(struct bch_fs *c, struct btree *b,
 		out = i->start;
 
 		for (k = start; k != end; k = n) {
-			n = bkey_next(k);
+			n = bkey_next_skip_noops(k, end);
 
 			if (bkey_deleted(k) && btree_node_is_extents(b))
 				continue;
@@ -261,7 +260,7 @@ static bool bch2_drop_whiteouts(struct btree *b)
 		out = i->start;
 
 		for (k = start; k != end; k = n) {
-			n = bkey_next(k);
+			n = bkey_next_skip_noops(k, end);
 
 			if (!bkey_whiteout(k)) {
 				bkey_copy(out, k);
@@ -680,14 +679,6 @@ static int validate_bset(struct bch_fs *c, struct btree *b,
 		struct bkey tmp;
 		const char *invalid;
 
-		if (btree_err_on(!k->u64s,
-				 BTREE_ERR_FIXABLE, c, b, i,
-				 "KEY_U64s 0: %zu bytes of metadata lost",
-				 vstruct_end(i) - (void *) k)) {
-			i->u64s = cpu_to_le16((u64 *) k - i->_data);
-			break;
-		}
-
 		if (btree_err_on(bkey_next(k) > vstruct_last(i),
 				 BTREE_ERR_FIXABLE, c, b, i,
 				 "key extends past end of bset")) {
@@ -756,7 +747,7 @@ static int validate_bset(struct bch_fs *c, struct btree *b,
 
 		prev_pos = u.k->p;
 		prev = k;
-		k = bkey_next(k);
+		k = bkey_next_skip_noops(k, vstruct_last(i));
 	}
 
 	SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
@@ -915,12 +906,12 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct btree *b, bool have_retry
 			continue;
 		}
 
-		k = bkey_next(k);
+		k = bkey_next_skip_noops(k, vstruct_last(i));
 	}
 
 	bch2_bset_build_aux_tree(b, b->set, false);
 
-	set_needs_whiteout(btree_bset_first(b));
+	set_needs_whiteout(btree_bset_first(b), true);
 
 	btree_node_reset_sib_u64s(b);
 out:
@@ -1425,7 +1416,7 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b,
 		: bch2_sort_keys(i->start, &sort_iter, false);
 	le16_add_cpu(&i->u64s, u64s);
 
-	clear_needs_whiteout(i);
+	set_needs_whiteout(i, false);
 
 	/* do we have data to write? */
 	if (b->written && !i->u64s)
@@ -1579,7 +1570,7 @@ bool bch2_btree_post_write_cleanup(struct bch_fs *c, struct btree *b)
 	}
 
 	for_each_bset(b, t)
-		set_needs_whiteout(bset(b, t));
+		set_needs_whiteout(bset(b, t), true);
 
 	bch2_btree_verify(c, b);