diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index d4806809fc0d..c1d3e685a5f2 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -1037,10 +1037,9 @@ void bch2_btree_node_read(struct bch_fs *c, struct btree *b,
 	rb->pick		= pick;
 	INIT_WORK(&rb->work, btree_node_read_work);
 	bio->bi_iter.bi_sector	= pick.ptr.offset;
-	bio->bi_iter.bi_size	= btree_bytes(c);
 	bio->bi_end_io		= btree_node_read_endio;
 	bio->bi_private		= b;
-	bch2_bio_map(bio, b->data);
+	bch2_bio_map(bio, b->data, btree_bytes(c));
 
 	set_btree_node_read_in_flight(b);
 
@@ -1502,11 +1501,10 @@ void __bch2_btree_node_write(struct bch_fs *c, struct btree *b,
 	wbio->data			= data;
 	wbio->wbio.order		= order;
 	wbio->wbio.used_mempool		= used_mempool;
-	wbio->wbio.bio.bi_iter.bi_size	= sectors_to_write << 9;
 	wbio->wbio.bio.bi_end_io	= btree_node_write_endio;
 	wbio->wbio.bio.bi_private	= b;
 
-	bch2_bio_map(&wbio->wbio.bio, data);
+	bch2_bio_map(&wbio->wbio.bio, data, sectors_to_write << 9);
 
 	/*
 	 * If we're appending to a leaf node, we don't technically need FUA -
diff --git a/fs/bcachefs/compress.c b/fs/bcachefs/compress.c
index 6b5b61f10fcb..3e91fa53985a 100644
--- a/fs/bcachefs/compress.c
+++ b/fs/bcachefs/compress.c
@@ -244,7 +244,16 @@ int bch2_bio_uncompress_inplace(struct bch_fs *c, struct bio *bio,
 	 * might have to free existing pages and retry allocation from mempool -
 	 * do this _after_ decompressing:
 	 */
-	bch2_bio_alloc_more_pages_pool(c, bio, crc->live_size << 9);
+	if (bio->bi_iter.bi_size < crc->live_size << 9) {
+		if (bch2_bio_alloc_pages(bio, (crc->live_size << 9) -
+					 bio->bi_iter.bi_size,
+					 GFP_NOFS)) {
+			bch2_bio_free_pages_pool(c, bio);
+			bio->bi_iter.bi_size = 0;
+			bio->bi_vcnt = 0;
+			bch2_bio_alloc_pages_pool(c, bio, crc->live_size << 9);
+		}
+	}
 
 	memcpy_to_bio(bio, bio->bi_iter, data.b + (crc->offset << 9));
 
diff --git a/fs/bcachefs/debug.c b/fs/bcachefs/debug.c
index 4c6fcb6f918e..7adc5ae20b9f 100644
--- a/fs/bcachefs/debug.c
+++ b/fs/bcachefs/debug.c
@@ -70,8 +70,7 @@ void __bch2_btree_verify(struct bch_fs *c, struct btree *b)
 			       GFP_NOIO,
 			       &c->btree_bio);
 	bio->bi_iter.bi_sector	= pick.ptr.offset;
-	bio->bi_iter.bi_size	= btree_bytes(c);
-	bch2_bio_map(bio, n_sorted);
+	bch2_bio_map(bio, n_sorted, btree_bytes(c));
 
 	submit_bio_wait(bio);
 
diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 01e85fae72d3..40acd1ec4645 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -399,11 +399,10 @@ static void ec_block_io(struct bch_fs *c, struct ec_stripe_buf *buf,
 		ec_bio->idx			= idx;
 
 		ec_bio->bio.bi_iter.bi_sector	= ptr->offset + buf->offset + (offset >> 9);
-		ec_bio->bio.bi_iter.bi_size	= b;
 		ec_bio->bio.bi_end_io		= ec_block_endio;
 		ec_bio->bio.bi_private		= cl;
 
-		bch2_bio_map(&ec_bio->bio, buf->data[idx] + offset);
+		bch2_bio_map(&ec_bio->bio, buf->data[idx] + offset, b);
 
 		closure_get(cl);
 		percpu_ref_get(&ca->io_ref);
diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
index 9d0cca0bdfa3..54b071b9ca2c 100644
--- a/fs/bcachefs/fs-io.c
+++ b/fs/bcachefs/fs-io.c
@@ -775,7 +775,7 @@ static int bio_add_page_contig(struct bio *bio, struct page *page)
 	else if (!bio_can_add_page_contig(bio, page))
 		return -1;
 
-	__bio_add_page(bio, page, PAGE_SIZE, 0);
+	BUG_ON(!bio_add_page(bio, page, PAGE_SIZE, 0));
 	return 0;
 }
 
@@ -913,7 +913,7 @@ static void readpage_bio_extend(struct readpages_iter *iter,
 			put_page(page);
 		}
 
-		__bio_add_page(bio, page, PAGE_SIZE, 0);
+		BUG_ON(!bio_add_page(bio, page, PAGE_SIZE, 0));
 	}
 }
 
@@ -1025,7 +1025,7 @@ void bch2_readahead(struct readahead_control *ractl)
 
 		rbio->bio.bi_iter.bi_sector = (sector_t) index << PAGE_SECTOR_SHIFT;
 		rbio->bio.bi_end_io = bch2_readpages_end_io;
-		__bio_add_page(&rbio->bio, page, PAGE_SIZE, 0);
+		BUG_ON(!bio_add_page(&rbio->bio, page, PAGE_SIZE, 0));
 
 		bchfs_read(&trans, iter, rbio, inode->v.i_ino,
 			   &readpages_iter);
diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index 8a090b0d9b03..8c43791bfbb1 100644
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -141,14 +141,13 @@ void bch2_bio_free_pages_pool(struct bch_fs *c, struct bio *bio)
 	bio->bi_vcnt = 0;
 }
 
-static void bch2_bio_alloc_page_pool(struct bch_fs *c, struct bio *bio,
-				    bool *using_mempool)
+static struct page *__bio_alloc_page_pool(struct bch_fs *c, bool *using_mempool)
 {
-	struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt++];
+	struct page *page;
 
 	if (likely(!*using_mempool)) {
-		bv->bv_page = alloc_page(GFP_NOIO);
-		if (unlikely(!bv->bv_page)) {
+		page = alloc_page(GFP_NOIO);
+		if (unlikely(!page)) {
 			mutex_lock(&c->bio_bounce_pages_lock);
 			*using_mempool = true;
 			goto pool_alloc;
@@ -156,57 +155,29 @@ static void bch2_bio_alloc_page_pool(struct bch_fs *c, struct bio *bio,
 		}
 	} else {
 pool_alloc:
-		bv->bv_page = mempool_alloc(&c->bio_bounce_pages, GFP_NOIO);
+		page = mempool_alloc(&c->bio_bounce_pages, GFP_NOIO);
 	}
 
-	bv->bv_len = PAGE_SIZE;
-	bv->bv_offset = 0;
+	return page;
 }
 
 void bch2_bio_alloc_pages_pool(struct bch_fs *c, struct bio *bio,
-			       size_t bytes)
+			       size_t size)
 {
 	bool using_mempool = false;
 
-	BUG_ON(DIV_ROUND_UP(bytes, PAGE_SIZE) > bio->bi_max_vecs);
+	while (size) {
+		struct page *page = __bio_alloc_page_pool(c, &using_mempool);
+		unsigned len = min(PAGE_SIZE, size);
 
-	bio->bi_iter.bi_size = bytes;
-
-	while (bio->bi_vcnt < DIV_ROUND_UP(bytes, PAGE_SIZE))
-		bch2_bio_alloc_page_pool(c, bio, &using_mempool);
+		BUG_ON(!bio_add_page(bio, page, len, 0));
+		size -= len;
+	}
 
 	if (using_mempool)
 		mutex_unlock(&c->bio_bounce_pages_lock);
 }
 
-void bch2_bio_alloc_more_pages_pool(struct bch_fs *c, struct bio *bio,
-				    size_t bytes)
-{
-	while (bio->bi_vcnt < DIV_ROUND_UP(bytes, PAGE_SIZE)) {
-		struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
-
-		BUG_ON(bio->bi_vcnt >= bio->bi_max_vecs);
-
-		bv->bv_page = alloc_page(GFP_NOIO);
-		if (!bv->bv_page) {
-			/*
-			 * We already allocated from mempool, we can't allocate from it again
-			 * without freeing the pages we already allocated or else we could
-			 * deadlock:
-			 */
-			bch2_bio_free_pages_pool(c, bio);
-			bch2_bio_alloc_pages_pool(c, bio, bytes);
-			return;
-		}
-
-		bv->bv_len = PAGE_SIZE;
-		bv->bv_offset = 0;
-		bio->bi_vcnt++;
-	}
-
-	bio->bi_iter.bi_size = bytes;
-}
-
 /* Writes */
 
 void bch2_submit_wbio_replicas(struct bch_write_bio *wbio, struct bch_fs *c,
@@ -491,8 +462,7 @@ static struct bio *bch2_write_bio_alloc(struct bch_fs *c,
 	wbio->bio.bi_opf	= src->bi_opf;
 
 	if (buf) {
-		bio->bi_iter.bi_size = output_available;
-		bch2_bio_map(bio, buf);
+		bch2_bio_map(bio, buf, output_available);
 		return bio;
 	}
 
@@ -502,31 +472,17 @@ static struct bio *bch2_write_bio_alloc(struct bch_fs *c,
 	 * We can't use mempool for more than c->sb.encoded_extent_max
 	 * worth of pages, but we'd like to allocate more if we can:
 	 */
-	while (bio->bi_iter.bi_size < output_available) {
-		unsigned len = min_t(unsigned, PAGE_SIZE,
-				     output_available - bio->bi_iter.bi_size);
-		struct page *p;
+	bch2_bio_alloc_pages_pool(c, bio,
+				  min_t(unsigned, output_available,
+					c->sb.encoded_extent_max << 9));
 
-		p = alloc_page(GFP_NOIO);
-		if (!p) {
-			unsigned pool_max =
-				min_t(unsigned, output_available,
-				      c->sb.encoded_extent_max << 9);
+	if (bio->bi_iter.bi_size < output_available)
+		*page_alloc_failed =
+			bch2_bio_alloc_pages(bio,
+					     output_available -
+					     bio->bi_iter.bi_size,
+					     GFP_NOFS) != 0;
 
-			if (bio_sectors(bio) < pool_max)
-				bch2_bio_alloc_pages_pool(c, bio, pool_max);
-			break;
-		}
-
-		bio->bi_io_vec[bio->bi_vcnt++] = (struct bio_vec) {
-			.bv_page	= p,
-			.bv_len		= len,
-			.bv_offset	= 0,
-		};
-		bio->bi_iter.bi_size += len;
-	}
-
-	*page_alloc_failed = bio->bi_vcnt < pages;
 	return bio;
 }
 
@@ -830,12 +786,6 @@ static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp)
 	}
 
 	dst->bi_iter.bi_size = total_output;
-
-	/* Free unneeded pages after compressing: */
-	if (to_wbio(dst)->bounce)
-		while (dst->bi_vcnt > DIV_ROUND_UP(dst->bi_iter.bi_size, PAGE_SIZE))
-			mempool_free(dst->bi_io_vec[--dst->bi_vcnt].bv_page,
-				     &c->bio_bounce_pages);
 do_write:
 	/* might have done a realloc... */
 
diff --git a/fs/bcachefs/io.h b/fs/bcachefs/io.h
index 84070b674187..61c8b8b3a459 100644
--- a/fs/bcachefs/io.h
+++ b/fs/bcachefs/io.h
@@ -13,7 +13,6 @@
 
 void bch2_bio_free_pages_pool(struct bch_fs *, struct bio *);
 void bch2_bio_alloc_pages_pool(struct bch_fs *, struct bio *, size_t);
-void bch2_bio_alloc_more_pages_pool(struct bch_fs *, struct bio *, size_t);
 
 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
 void bch2_latency_acct(struct bch_dev *, u64, int);
diff --git a/fs/bcachefs/journal_io.c b/fs/bcachefs/journal_io.c
index 4e0c63f0076f..2531379e67c6 100644
--- a/fs/bcachefs/journal_io.c
+++ b/fs/bcachefs/journal_io.c
@@ -494,9 +494,8 @@ static int journal_read_bucket(struct bch_dev *ca,
 			bio = bio_kmalloc(nr_bvecs, GFP_KERNEL);
 			bio_init(bio, ca->disk_sb.bdev, bio->bi_inline_vecs, nr_bvecs, REQ_OP_READ);
 
-			bio->bi_iter.bi_sector	= offset;
-			bio->bi_iter.bi_size	= sectors_read << 9;
-			bch2_bio_map(bio, buf->data);
+			bio->bi_iter.bi_sector = offset;
+			bch2_bio_map(bio, buf->data, sectors_read << 9);
 
 			ret = submit_bio_wait(bio);
 			kfree(bio);
@@ -1086,10 +1085,9 @@ void bch2_journal_write(struct closure *cl)
 		bio_reset(bio, ca->disk_sb.bdev,
 			  REQ_OP_WRITE|REQ_SYNC|REQ_META|REQ_PREFLUSH|REQ_FUA);
 		bio->bi_iter.bi_sector	= ptr->offset;
-		bio->bi_iter.bi_size	= sectors << 9;
 		bio->bi_end_io		= journal_write_endio;
 		bio->bi_private		= ca;
-		bch2_bio_map(bio, jset);
+		bch2_bio_map(bio, jset, sectors << 9);
 
 		trace_journal_write(bio);
 		closure_bio_submit(bio, cl);
diff --git a/fs/bcachefs/super-io.c b/fs/bcachefs/super-io.c
index b991238c5bd2..af6fb90413e9 100644
--- a/fs/bcachefs/super-io.c
+++ b/fs/bcachefs/super-io.c
@@ -476,8 +476,7 @@ static const char *read_one_super(struct bch_sb_handle *sb, u64 offset)
 reread:
 	bio_reset(sb->bio, sb->bdev, REQ_OP_READ|REQ_SYNC|REQ_META);
 	sb->bio->bi_iter.bi_sector = offset;
-	sb->bio->bi_iter.bi_size = PAGE_SIZE << sb->page_order;
-	bch2_bio_map(sb->bio, sb->sb);
+	bch2_bio_map(sb->bio, sb->sb, PAGE_SIZE << sb->page_order);
 
 	if (submit_bio_wait(sb->bio))
 		return "IO error";
@@ -582,12 +581,11 @@ int bch2_read_super(const char *path, struct bch_opts *opts,
 	 */
 	bio_reset(sb->bio, sb->bdev, REQ_OP_READ|REQ_SYNC|REQ_META);
 	sb->bio->bi_iter.bi_sector = BCH_SB_LAYOUT_SECTOR;
-	sb->bio->bi_iter.bi_size = sizeof(struct bch_sb_layout);
 	/*
 	 * use sb buffer to read layout, since sb buffer is page aligned but
 	 * layout won't be:
 	 */
-	bch2_bio_map(sb->bio, sb->sb);
+	bch2_bio_map(sb->bio, sb->sb, sizeof(struct bch_sb_layout));
 
 	err = "IO error";
 	if (submit_bio_wait(sb->bio))
@@ -653,10 +651,9 @@ static void read_back_super(struct bch_fs *c, struct bch_dev *ca)
 
 	bio_reset(bio, ca->disk_sb.bdev, REQ_OP_READ|REQ_SYNC|REQ_META);
 	bio->bi_iter.bi_sector	= le64_to_cpu(sb->layout.sb_offset[0]);
-	bio->bi_iter.bi_size	= PAGE_SIZE;
 	bio->bi_end_io		= write_super_endio;
 	bio->bi_private		= ca;
-	bch2_bio_map(bio, ca->sb_read_scratch);
+	bch2_bio_map(bio, ca->sb_read_scratch, PAGE_SIZE);
 
 	this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_SB],
 		     bio_sectors(bio));
@@ -678,12 +675,11 @@ static void write_one_super(struct bch_fs *c, struct bch_dev *ca, unsigned idx)
 
 	bio_reset(bio, ca->disk_sb.bdev, REQ_OP_WRITE|REQ_SYNC|REQ_META);
 	bio->bi_iter.bi_sector	= le64_to_cpu(sb->offset);
-	bio->bi_iter.bi_size	=
-		roundup((size_t) vstruct_bytes(sb),
-			bdev_logical_block_size(ca->disk_sb.bdev));
 	bio->bi_end_io		= write_super_endio;
 	bio->bi_private		= ca;
-	bch2_bio_map(bio, sb);
+	bch2_bio_map(bio, sb,
+		     roundup((size_t) vstruct_bytes(sb),
+			     bdev_logical_block_size(ca->disk_sb.bdev)));
 
 	this_cpu_add(ca->io_done->sectors[WRITE][BCH_DATA_SB],
 		     bio_sectors(bio));
diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index 0ca1fb59f54d..fc2ca798fbc3 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -506,33 +506,18 @@ size_t bch2_pd_controller_print_debug(struct bch_pd_controller *pd, char *buf)
 
 /* misc: */
 
-void bch2_bio_map(struct bio *bio, void *base)
+void bch2_bio_map(struct bio *bio, void *base, size_t size)
 {
-	size_t size = bio->bi_iter.bi_size;
-	struct bio_vec *bv = bio->bi_io_vec;
-
-	BUG_ON(!bio->bi_iter.bi_size);
-	BUG_ON(bio->bi_vcnt);
-	BUG_ON(!bio->bi_max_vecs);
-
-	bv->bv_offset = base ? offset_in_page(base) : 0;
-	goto start;
-
-	for (; size; bio->bi_vcnt++, bv++) {
-		BUG_ON(bio->bi_vcnt >= bio->bi_max_vecs);
-
-		bv->bv_offset	= 0;
-start:		bv->bv_len	= min_t(size_t, PAGE_SIZE - bv->bv_offset,
-					size);
-		if (base) {
-			bv->bv_page = is_vmalloc_addr(base)
+	while (size) {
+		struct page *page = is_vmalloc_addr(base)
 				? vmalloc_to_page(base)
 				: virt_to_page(base);
+		unsigned offset = offset_in_page(base);
+		unsigned len = min_t(size_t, PAGE_SIZE - offset, size);
 
-			base += bv->bv_len;
-		}
-
-		size -= bv->bv_len;
+		BUG_ON(!bio_add_page(bio, page, len, offset));
+		size -= len;
+		base += len;
 	}
 }
 
diff --git a/fs/bcachefs/util.h b/fs/bcachefs/util.h
index c0910f230caf..baa236b4247c 100644
--- a/fs/bcachefs/util.h
+++ b/fs/bcachefs/util.h
@@ -503,7 +503,7 @@ static inline unsigned fract_exp_two(unsigned x, unsigned fract_bits)
 	return x;
 }
 
-void bch2_bio_map(struct bio *bio, void *base);
+void bch2_bio_map(struct bio *bio, void *base, size_t);
 int bch2_bio_alloc_pages(struct bio *, size_t, gfp_t);
 
 static inline sector_t bdev_sectors(struct block_device *bdev)