diff --git a/block/bio.c b/block/bio.c
index 3d4a072..471d738 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -748,6 +748,7 @@
 				}
 			}
 
+			bio->bi_iter.bi_size += len;
 			goto done;
 		}
 
@@ -764,20 +765,6 @@
 		return 0;
 
 	/*
-	 * we might lose a segment or two here, but rather that than
-	 * make this too complex.
-	 */
-
-	while (bio->bi_phys_segments >= queue_max_segments(q)) {
-
-		if (retried_segments)
-			return 0;
-
-		retried_segments = 1;
-		blk_recount_segments(q, bio);
-	}
-
-	/*
 	 * setup the new entry, we might clear it again later if we
 	 * cannot add the page
 	 */
@@ -785,6 +772,23 @@
 	bvec->bv_page = page;
 	bvec->bv_len = len;
 	bvec->bv_offset = offset;
+	bio->bi_vcnt++;
+	bio->bi_phys_segments++;
+	bio->bi_iter.bi_size += len;
+
+	/*
+	 * Perform a recount if the number of segments is greater
+	 * than queue_max_segments(q).
+	 */
+
+	while (bio->bi_phys_segments > queue_max_segments(q)) {
+
+		if (retried_segments)
+			goto failed;
+
+		retried_segments = 1;
+		blk_recount_segments(q, bio);
+	}
 
 	/*
 	 * if queue has other restrictions (eg varying max sector size
@@ -795,7 +799,7 @@
 		struct bvec_merge_data bvm = {
 			.bi_bdev = bio->bi_bdev,
 			.bi_sector = bio->bi_iter.bi_sector,
-			.bi_size = bio->bi_iter.bi_size,
+			.bi_size = bio->bi_iter.bi_size - len,
 			.bi_rw = bio->bi_rw,
 		};
 
@@ -803,23 +807,25 @@
 		 * merge_bvec_fn() returns number of bytes it can accept
 		 * at this offset
 		 */
-		if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
-			bvec->bv_page = NULL;
-			bvec->bv_len = 0;
-			bvec->bv_offset = 0;
-			return 0;
-		}
+		if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len)
+			goto failed;
 	}
 
 	/* If we may be able to merge these biovecs, force a recount */
-	if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
+	if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec)))
 		bio->bi_flags &= ~(1 << BIO_SEG_VALID);
 
-	bio->bi_vcnt++;
-	bio->bi_phys_segments++;
  done:
-	bio->bi_iter.bi_size += len;
 	return len;
+
+ failed:
+	bvec->bv_page = NULL;
+	bvec->bv_len = 0;
+	bvec->bv_offset = 0;
+	bio->bi_vcnt--;
+	bio->bi_iter.bi_size -= len;
+	blk_recount_segments(q, bio);
+	return 0;
 }
 
 /**