diff --git a/lib/ftl/ftl_core.c b/lib/ftl/ftl_core.c
index 83687bca2..818a377ed 100644
--- a/lib/ftl/ftl_core.c
+++ b/lib/ftl/ftl_core.c
@@ -789,9 +789,9 @@ ftl_lba_read_next_ppa(struct ftl_io *io, struct ftl_ppa *ppa,
 	struct ftl_ppa next_ppa;
 	size_t i;
 
-	*ppa = ftl_l2p_get(dev, io->lba + lbk);
+	*ppa = ftl_l2p_get(dev, io->lba.single + lbk);
 
-	SPDK_DEBUGLOG(SPDK_LOG_FTL_CORE, "Read ppa:%lx, lba:%lu\n", ppa->ppa, io->lba);
+	SPDK_DEBUGLOG(SPDK_LOG_FTL_CORE, "Read ppa:%lx, lba:%lu\n", ppa->ppa, io->lba.single);
 
 	/* If the PPA is invalid, skip it (the buffer should already be zero'ed) */
 	if (ftl_ppa_invalid(*ppa)) {
@@ -800,7 +800,7 @@ ftl_lba_read_next_ppa(struct ftl_io *io, struct ftl_ppa *ppa,
 	}
 
 	if (ftl_ppa_cached(*ppa)) {
-		if (!ftl_ppa_cache_read(io, io->lba + lbk, *ppa, ftl_io_iovec_addr(io))) {
+		if (!ftl_ppa_cache_read(io, io->lba.single + lbk, *ppa, ftl_io_iovec_addr(io))) {
 			ftl_trace_completion(io->dev, io, FTL_TRACE_COMPLETION_CACHE);
 			return 0;
 		}
@@ -810,7 +810,7 @@ ftl_lba_read_next_ppa(struct ftl_io *io, struct ftl_ppa *ppa,
 	}
 
 	for (i = 1; i < ftl_io_iovec_len_left(io); ++i) {
-		next_ppa = ftl_l2p_get(dev, io->lba + lbk + i);
+		next_ppa = ftl_l2p_get(dev, io->lba.single + lbk + i);
 
 		if (ftl_ppa_invalid(next_ppa) || ftl_ppa_cached(next_ppa)) {
 			break;
@@ -1040,7 +1040,7 @@ ftl_submit_child_write(struct ftl_wptr *wptr, struct ftl_io *io, int lbk_cnt)
 	}
 
 	rc = spdk_nvme_ns_cmd_write_with_md(dev->ns, ftl_get_write_qpair(dev),
-					    child->iov.iov_base, child->md,
+					    ftl_io_iovec_addr(child), child->md,
 					    ftl_ppa_addr_pack(dev, wptr->ppa),
 					    lbk_cnt, ftl_io_cmpl_cb, child, 0, 0, 0);
 	if (rc) {
@@ -1249,7 +1249,7 @@ ftl_rwb_entry_fill(struct ftl_rwb_entry *entry, struct ftl_io *io)
 	entry->trace = io->trace;
 
 	if (entry->md) {
-		memcpy(entry->md, &entry->lba, sizeof(io->lba));
+		memcpy(entry->md, &entry->lba, sizeof(entry->lba));
 	}
 }
 
diff --git a/lib/ftl/ftl_io.c b/lib/ftl/ftl_io.c
index 276fcb4ef..9bda906ed 100644
--- a/lib/ftl/ftl_io.c
+++ b/lib/ftl/ftl_io.c
@@ -76,9 +76,9 @@ struct iovec *
 ftl_io_iovec(struct ftl_io *io)
 {
 	if (io->iov_cnt > 1) {
-		return io->iovs;
+		return io->iov.vector;
 	} else {
-		return &io->iov;
+		return &io->iov.single;
 	}
 }
 
@@ -86,9 +86,9 @@ uint64_t
 ftl_io_current_lba(struct ftl_io *io)
 {
 	if (io->flags & FTL_IO_VECTOR_LBA) {
-		return io->lbas[io->pos];
+		return io->lba.vector[io->pos];
 	} else {
-		return io->lba + io->pos;
+		return io->lba.single + io->pos;
 	}
 }
 
@@ -157,12 +157,12 @@ ftl_io_init_iovec(struct ftl_io *io, void *buf,
 	size_t i;
 
 	if (iov_cnt > 1) {
-		iov = io->iovs = calloc(iov_cnt, sizeof(*iov));
+		iov = io->iov.vector = calloc(iov_cnt, sizeof(*iov));
 		if (!iov) {
 			return -ENOMEM;
 		}
 	} else {
-		iov = &io->iov;
+		iov = &io->iov.single;
 	}
 
 	io->iov_pos = 0;
@@ -182,7 +182,7 @@ ftl_io_init(struct ftl_io *io, struct spdk_ftl_dev *dev,
 	io->flags |= flags | FTL_IO_INITIALIZED;
 	io->type = type;
 	io->dev = dev;
-	io->lba = FTL_LBA_INVALID;
+	io->lba.single = FTL_LBA_INVALID;
 	io->cb.fn = fn;
 	io->cb.ctx = ctx;
 	io->trace = ftl_trace_alloc_id(dev);
@@ -286,14 +286,14 @@ ftl_io_user_init(struct spdk_ftl_dev *dev, struct ftl_io *io, uint64_t lba, size
 
 	ftl_io_init(io, dev, cb_fn, cb_arg, 0, type);
 
-	io->lba = lba;
+	io->lba.single = lba;
 	io->lbk_cnt = lbk_cnt;
 	io->iov_cnt = iov_cnt;
 
 	if (iov_cnt > 1) {
-		io->iovs = iov;
+		io->iov.vector = iov;
 	} else {
-		io->iov = *iov;
+		io->iov.single = *iov;
 	}
 
 	ftl_trace_lba_io_init(io->dev, io);
@@ -307,7 +307,7 @@ _ftl_io_free(struct ftl_io *io)
 	assert(LIST_EMPTY(&io->children));
 
 	if ((io->flags & FTL_IO_INTERNAL) && io->iov_cnt > 1) {
-		free(io->iovs);
+		free(io->iov.vector);
 	}
 
 	if (pthread_spin_destroy(&io->lock)) {
diff --git a/lib/ftl/ftl_io.h b/lib/ftl/ftl_io.h
index 71267b646..b6624dd21 100644
--- a/lib/ftl/ftl_io.h
+++ b/lib/ftl/ftl_io.h
@@ -144,11 +144,11 @@ struct ftl_io {
 
 	union {
 		/* LBA table */
-		uint64_t			*lbas;
+		uint64_t			*vector;
 
 		/* First LBA */
-		uint64_t			lba;
-	};
+		uint64_t			single;
+	} lba;
 
 	/* First PPA */
 	struct ftl_ppa				ppa;
@@ -161,11 +161,11 @@ struct ftl_io {
 
 	union {
 		/* IO vector table */
-		struct iovec			*iovs;
+		struct iovec			*vector;
 
 		/* Single iovec */
-		struct iovec			iov;
-	};
+		struct iovec			single;
+	} iov;
 
 	/* Metadata */
 	void					*md;
diff --git a/lib/ftl/ftl_reloc.c b/lib/ftl/ftl_reloc.c
index a38052eef..5318c31f6 100644
--- a/lib/ftl/ftl_reloc.c
+++ b/lib/ftl/ftl_reloc.c
@@ -213,8 +213,8 @@ ftl_reloc_prep(struct ftl_band_reloc *breloc)
 static void
 ftl_reloc_free_io(struct ftl_band_reloc *breloc, struct ftl_io *io)
 {
-	spdk_dma_free(io->iov.iov_base);
-	free(io->lbas);
+	spdk_dma_free(io->iov.single.iov_base);
+	free(io->lba.vector);
 	spdk_ring_enqueue(breloc->free_queue, (void **)&io, 1);
 }
 
@@ -394,18 +394,18 @@ ftl_reloc_io_reinit(struct ftl_io *io, struct ftl_band_reloc *breloc,
 
 	io->ppa = ppa;
 	io->band = breloc->band;
-	io->lbas = calloc(io->lbk_cnt, sizeof(uint64_t));
+	io->lba.vector = calloc(io->lbk_cnt, sizeof(uint64_t));
 
 	for (i = 0; i < io->lbk_cnt; ++i) {
 		ppa.lbk = io->ppa.lbk + i;
 		lbkoff = ftl_band_lbkoff_from_ppa(breloc->band, ppa);
 
 		if (!ftl_band_lbkoff_valid(breloc->band, lbkoff)) {
-			io->lbas[i] = FTL_LBA_INVALID;
+			io->lba.vector[i] = FTL_LBA_INVALID;
 			continue;
 		}
 
-		io->lbas[i] = breloc->band->md.lba_map[lbkoff];
+		io->lba.vector[i] = breloc->band->md.lba_map[lbkoff];
 	}
 
 	ftl_trace_lba_io_init(io->dev, io);
diff --git a/lib/ftl/ftl_trace.c b/lib/ftl/ftl_trace.c
index 543b64040..c4cf47334 100644
--- a/lib/ftl/ftl_trace.c
+++ b/lib/ftl/ftl_trace.c
@@ -224,7 +224,7 @@ ftl_trace_lba_io_init(struct spdk_ftl_dev *dev, const struct ftl_io *io)
 		}
 	}
 
-	spdk_trace_record(tpoint_id, io->trace, io->lbk_cnt, 0, io->lba);
+	spdk_trace_record(tpoint_id, io->trace, io->lbk_cnt, 0, io->lba.single);
 }
 
 void
@@ -233,7 +233,7 @@ ftl_trace_rwb_fill(struct spdk_ftl_dev *dev, const struct ftl_io *io)
 	assert(io->trace != FTL_TRACE_INVALID_ID);
 
 	spdk_trace_record(FTL_TRACE_WRITE_RWB_FILL(ftl_trace_io_source(io)), io->trace,
-			  0, 0, io->lba + io->pos);
+			  0, 0, io->lba.single + io->pos);
 }
 
 void
@@ -298,7 +298,7 @@ ftl_trace_completion(struct spdk_ftl_dev *dev, const struct ftl_io *io,
 		}
 	}
 
-	spdk_trace_record(tpoint_id, io->trace, 0, 0, io->lba);
+	spdk_trace_record(tpoint_id, io->trace, 0, 0, io->lba.single);
 }
 
 void
diff --git a/test/unit/lib/ftl/ftl_reloc.c/ftl_reloc_ut.c b/test/unit/lib/ftl/ftl_reloc.c/ftl_reloc_ut.c
index 20d2e8eb0..1079a64b7 100644
--- a/test/unit/lib/ftl/ftl_reloc.c/ftl_reloc_ut.c
+++ b/test/unit/lib/ftl/ftl_reloc.c/ftl_reloc_ut.c
@@ -156,7 +156,7 @@ ftl_io_init_internal(const struct ftl_io_init_opts *opts)
 	io->cb.fn = opts->fn;
 	io->cb.ctx = io;
 	io->lbk_cnt = opts->req_size;
-	io->iov.iov_base = opts->data;
+	io->iov.single.iov_base = opts->data;
 	return io;
 }