bcachefs: Clean up key merging

This patch simplifies the key merging code by getting rid of partial
merges - it's simpler and saner if we just don't merge extents when
they'd overflow k->size.

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

1 files changed, 20 insertions, 30 deletions

diff --git a/fs/bcachefs/extents.c b/fs/bcachefs/extents.c
index 1f28dea26ca2..2ced3557e13b 100644
--- a/fs/bcachefs/extents.c
+++ b/fs/bcachefs/extents.c
@@ -229,17 +229,16 @@ void bch2_extent_to_text(struct printbuf *out, struct bch_fs *c,
 	bch2_bkey_ptrs_to_text(out, c, k);
 }
 
-enum merge_result bch2_extent_merge(struct bch_fs *c,
-				    struct bkey_s _l, struct bkey_s _r)
+bool bch2_extent_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
 {
 	struct bkey_s_extent l = bkey_s_to_extent(_l);
-	struct bkey_s_extent r = bkey_s_to_extent(_r);
+	struct bkey_s_c_extent r = bkey_s_c_to_extent(_r);
 	union bch_extent_entry *en_l = l.v->start;
-	union bch_extent_entry *en_r = r.v->start;
+	const union bch_extent_entry *en_r = r.v->start;
 	struct bch_extent_crc_unpacked crc_l, crc_r;
 
 	if (bkey_val_u64s(l.k) != bkey_val_u64s(r.k))
-		return BCH_MERGE_NOMERGE;
+		return false;
 
 	crc_l = bch2_extent_crc_unpack(l.k, NULL);
 
@@ -247,7 +246,7 @@ enum merge_result bch2_extent_merge(struct bch_fs *c,
 		en_r = vstruct_idx(r.v, (u64 *) en_l - l.v->_data);
 
 		if (extent_entry_type(en_l) != extent_entry_type(en_r))
-			return BCH_MERGE_NOMERGE;
+			return false;
 
 		switch (extent_entry_type(en_l)) {
 		case BCH_EXTENT_ENTRY_ptr: {
@@ -258,20 +257,20 @@ enum merge_result bch2_extent_merge(struct bch_fs *c,
 			if (lp->offset + crc_l.compressed_size != rp->offset ||
 			    lp->dev			!= rp->dev ||
 			    lp->gen			!= rp->gen)
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			/* We don't allow extents to straddle buckets: */
 			ca = bch_dev_bkey_exists(c, lp->dev);
 
 			if (PTR_BUCKET_NR(ca, lp) != PTR_BUCKET_NR(ca, rp))
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			break;
 		}
 		case BCH_EXTENT_ENTRY_stripe_ptr:
 			if (en_l->stripe_ptr.block	!= en_r->stripe_ptr.block ||
 			    en_l->stripe_ptr.idx	!= en_r->stripe_ptr.idx)
-				return BCH_MERGE_NOMERGE;
+				return false;
 			break;
 		case BCH_EXTENT_ENTRY_crc32:
 		case BCH_EXTENT_ENTRY_crc64:
@@ -282,30 +281,30 @@ enum merge_result bch2_extent_merge(struct bch_fs *c,
 			if (crc_l.csum_type		!= crc_r.csum_type ||
 			    crc_l.compression_type	!= crc_r.compression_type ||
 			    crc_l.nonce			!= crc_r.nonce)
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			if (crc_l.offset + crc_l.live_size != crc_l.compressed_size ||
 			    crc_r.offset)
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			if (!bch2_checksum_mergeable(crc_l.csum_type))
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			if (crc_is_compressed(crc_l))
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			if (crc_l.csum_type &&
 			    crc_l.uncompressed_size +
 			    crc_r.uncompressed_size > c->sb.encoded_extent_max)
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			if (crc_l.uncompressed_size + crc_r.uncompressed_size >
 			    bch2_crc_field_size_max[extent_entry_type(en_l)])
-				return BCH_MERGE_NOMERGE;
+				return false;
 
 			break;
 		default:
-			return BCH_MERGE_NOMERGE;
+			return false;
 		}
 	}
 
@@ -333,8 +332,7 @@ enum merge_result bch2_extent_merge(struct bch_fs *c,
 	}
 
 	bch2_key_resize(l.k, l.k->size + r.k->size);
-
-	return BCH_MERGE_MERGE;
+	return true;
 }
 
 /* KEY_TYPE_reservation: */
@@ -362,25 +360,17 @@ void bch2_reservation_to_text(struct printbuf *out, struct bch_fs *c,
 	       r.v->nr_replicas);
 }
 
-enum merge_result bch2_reservation_merge(struct bch_fs *c,
-					 struct bkey_s _l, struct bkey_s _r)
+bool bch2_reservation_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
 {
 	struct bkey_s_reservation l = bkey_s_to_reservation(_l);
-	struct bkey_s_reservation r = bkey_s_to_reservation(_r);
+	struct bkey_s_c_reservation r = bkey_s_c_to_reservation(_r);
 
 	if (l.v->generation != r.v->generation ||
 	    l.v->nr_replicas != r.v->nr_replicas)
-		return BCH_MERGE_NOMERGE;
-
-	if ((u64) l.k->size + r.k->size > KEY_SIZE_MAX) {
-		bch2_key_resize(l.k, KEY_SIZE_MAX);
-		bch2_cut_front_s(l.k->p, r.s);
-		return BCH_MERGE_PARTIAL;
-	}
+		return false;
 
 	bch2_key_resize(l.k, l.k->size + r.k->size);
-
-	return BCH_MERGE_MERGE;
+	return true;
 }
 
 /* Extent checksum entries: */