diff --git a/fs/iomap/Makefile b/fs/iomap/Makefile
index 381d76c5c232..69e8ebb41302 100644
--- a/fs/iomap/Makefile
+++ b/fs/iomap/Makefile
@@ -12,6 +12,7 @@ iomap-y				+= trace.o \
 				   iter.o
 iomap-$(CONFIG_BLOCK)		+= buffered-io.o \
 				   direct-io.o \
+				   ioend.o \
 				   fiemap.o \
 				   seek.o
 iomap-$(CONFIG_SWAP)		+= swapfile.o
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 8c18fb2a82e0..0b68c9584a7f 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -40,7 +40,8 @@ struct iomap_folio_state {
 	unsigned long		state[];
 };
 
-static struct bio_set iomap_ioend_bioset;
+struct bio_set iomap_ioend_bioset;
+EXPORT_SYMBOL_GPL(iomap_ioend_bioset);
 
 static inline bool ifs_is_fully_uptodate(struct folio *folio,
 		struct iomap_folio_state *ifs)
@@ -1539,15 +1540,15 @@ static void iomap_finish_folio_write(struct inode *inode, struct folio *folio,
  * ioend after this.
  */
 static u32
-iomap_finish_ioend(struct iomap_ioend *ioend, int error)
+iomap_finish_ioend_buffered(struct iomap_ioend *ioend)
 {
 	struct inode *inode = ioend->io_inode;
 	struct bio *bio = &ioend->io_bio;
 	struct folio_iter fi;
 	u32 folio_count = 0;
 
-	if (error) {
-		mapping_set_error(inode->i_mapping, error);
+	if (ioend->io_error) {
+		mapping_set_error(inode->i_mapping, ioend->io_error);
 		if (!bio_flagged(bio, BIO_QUIET)) {
 			pr_err_ratelimited(
 "%s: writeback error on inode %lu, offset %lld, sector %llu",
@@ -1566,6 +1567,24 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error)
 	return folio_count;
 }
 
+static u32
+iomap_finish_ioend(struct iomap_ioend *ioend, int error)
+{
+	if (ioend->io_parent) {
+		struct bio *bio = &ioend->io_bio;
+
+		ioend = ioend->io_parent;
+		bio_put(bio);
+	}
+
+	if (error)
+		cmpxchg(&ioend->io_error, 0, error);
+
+	if (!atomic_dec_and_test(&ioend->io_remaining))
+		return 0;
+	return iomap_finish_ioend_buffered(ioend);
+}
+
 /*
  * Ioend completion routine for merged bios. This can only be called from task
  * contexts as merged ioends can be of unbound length. Hence we have to break up
@@ -1667,8 +1686,10 @@ EXPORT_SYMBOL_GPL(iomap_sort_ioends);
 
 static void iomap_writepage_end_bio(struct bio *bio)
 {
-	iomap_finish_ioend(iomap_ioend_from_bio(bio),
-			blk_status_to_errno(bio->bi_status));
+	struct iomap_ioend *ioend = iomap_ioend_from_bio(bio);
+
+	ioend->io_error = blk_status_to_errno(bio->bi_status);
+	iomap_finish_ioend_buffered(ioend);
 }
 
 /*
@@ -1713,7 +1734,6 @@ static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc,
 		struct writeback_control *wbc, struct inode *inode, loff_t pos,
 		u16 ioend_flags)
 {
-	struct iomap_ioend *ioend;
 	struct bio *bio;
 
 	bio = bio_alloc_bioset(wpc->iomap.bdev, BIO_MAX_VECS,
@@ -1721,21 +1741,10 @@ static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc,
 			       GFP_NOFS, &iomap_ioend_bioset);
 	bio->bi_iter.bi_sector = iomap_sector(&wpc->iomap, pos);
 	bio->bi_end_io = iomap_writepage_end_bio;
-	wbc_init_bio(wbc, bio);
 	bio->bi_write_hint = inode->i_write_hint;
-
-	ioend = iomap_ioend_from_bio(bio);
-	INIT_LIST_HEAD(&ioend->io_list);
-	ioend->io_flags = ioend_flags;
-	if (pos > wpc->iomap.offset)
-		wpc->iomap.flags &= ~IOMAP_F_BOUNDARY;
-	ioend->io_inode = inode;
-	ioend->io_size = 0;
-	ioend->io_offset = pos;
-	ioend->io_sector = bio->bi_iter.bi_sector;
-
+	wbc_init_bio(wbc, bio);
 	wpc->nr_folios = 0;
-	return ioend;
+	return iomap_init_ioend(inode, bio, pos, ioend_flags);
 }
 
 static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos,
diff --git a/fs/iomap/ioend.c b/fs/iomap/ioend.c
new file mode 100644
index 000000000000..1b032323ee4e
--- /dev/null
+++ b/fs/iomap/ioend.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2024 Christoph Hellwig.
+ */
+#include <linux/iomap.h>
+
+struct iomap_ioend *iomap_init_ioend(struct inode *inode,
+		struct bio *bio, loff_t file_offset, u16 ioend_flags)
+{
+	struct iomap_ioend *ioend = iomap_ioend_from_bio(bio);
+
+	atomic_set(&ioend->io_remaining, 1);
+	ioend->io_error = 0;
+	ioend->io_parent = NULL;
+	INIT_LIST_HEAD(&ioend->io_list);
+	ioend->io_flags = ioend_flags;
+	ioend->io_inode = inode;
+	ioend->io_offset = file_offset;
+	ioend->io_size = bio->bi_iter.bi_size;
+	ioend->io_sector = bio->bi_iter.bi_sector;
+	return ioend;
+}
+EXPORT_SYMBOL_GPL(iomap_init_ioend);
+
+/*
+ * Split up to the first @max_len bytes from @ioend if the ioend covers more
+ * than @max_len bytes.
+ *
+ * If @is_append is set, the split will be based on the hardware limits for
+ * REQ_OP_ZONE_APPEND commands and can be less than @max_len if the hardware
+ * limits don't allow the entire @max_len length.
+ *
+ * The bio embedded into @ioend must be a REQ_OP_WRITE because the block layer
+ * does not allow splitting REQ_OP_ZONE_APPEND bios.  The file systems has to
+ * switch the operation after this call, but before submitting the bio.
+ */
+struct iomap_ioend *iomap_split_ioend(struct iomap_ioend *ioend,
+		unsigned int max_len, bool is_append)
+{
+	struct bio *bio = &ioend->io_bio;
+	struct iomap_ioend *split_ioend;
+	unsigned int nr_segs;
+	int sector_offset;
+	struct bio *split;
+
+	if (is_append) {
+		struct queue_limits *lim = bdev_limits(bio->bi_bdev);
+
+		max_len = min(max_len,
+			      lim->max_zone_append_sectors << SECTOR_SHIFT);
+
+		sector_offset = bio_split_rw_at(bio, lim, &nr_segs, max_len);
+		if (unlikely(sector_offset < 0))
+			return ERR_PTR(sector_offset);
+		if (!sector_offset)
+			return NULL;
+	} else {
+		if (bio->bi_iter.bi_size <= max_len)
+			return NULL;
+		sector_offset = max_len >> SECTOR_SHIFT;
+	}
+
+	/* ensure the split ioend is still block size aligned */
+	sector_offset = ALIGN_DOWN(sector_offset << SECTOR_SHIFT,
+			i_blocksize(ioend->io_inode)) >> SECTOR_SHIFT;
+
+	split = bio_split(bio, sector_offset, GFP_NOFS, &iomap_ioend_bioset);
+	if (IS_ERR_OR_NULL(split))
+		return ERR_CAST(split);
+	split->bi_private = bio->bi_private;
+	split->bi_end_io = bio->bi_end_io;
+
+	split_ioend = iomap_init_ioend(ioend->io_inode, split, ioend->io_offset,
+			ioend->io_flags);
+	split_ioend->io_parent = ioend;
+
+	atomic_inc(&ioend->io_remaining);
+	ioend->io_offset += split_ioend->io_size;
+	ioend->io_size -= split_ioend->io_size;
+
+	split_ioend->io_sector = ioend->io_sector;
+	if (!is_append)
+		ioend->io_sector += (split_ioend->io_size >> SECTOR_SHIFT);
+	return split_ioend;
+}
+EXPORT_SYMBOL_GPL(iomap_split_ioend);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 36a7298b6cea..0d221fbe0eb3 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -358,6 +358,9 @@ struct iomap_ioend {
 	struct list_head	io_list;	/* next ioend in chain */
 	u16			io_flags;	/* IOMAP_IOEND_* */
 	struct inode		*io_inode;	/* file being written to */
+	atomic_t		io_remaining;	/* completetion defer count */
+	int			io_error;	/* stashed away status */
+	struct iomap_ioend	*io_parent;	/* parent for completions */
 	size_t			io_size;	/* size of the extent */
 	loff_t			io_offset;	/* offset in the file */
 	sector_t		io_sector;	/* start sector of ioend */
@@ -408,6 +411,10 @@ struct iomap_writepage_ctx {
 	u32			nr_folios;	/* folios added to the ioend */
 };
 
+struct iomap_ioend *iomap_init_ioend(struct inode *inode, struct bio *bio,
+		loff_t file_offset, u16 ioend_flags);
+struct iomap_ioend *iomap_split_ioend(struct iomap_ioend *ioend,
+		unsigned int max_len, bool is_append);
 void iomap_finish_ioends(struct iomap_ioend *ioend, int error);
 void iomap_ioend_try_merge(struct iomap_ioend *ioend,
 		struct list_head *more_ioends);
@@ -479,4 +486,6 @@ int iomap_swapfile_activate(struct swap_info_struct *sis,
 # define iomap_swapfile_activate(sis, swapfile, pagespan, ops)	(-EIO)
 #endif /* CONFIG_SWAP */
 
+extern struct bio_set iomap_ioend_bioset;
+
 #endif /* LINUX_IOMAP_H */
