diff --git a/include/os/freebsd/spl/sys/uio.h b/include/os/freebsd/spl/sys/uio.h
index b71f2f2e5625..b9d41903ea63 100644
--- a/include/os/freebsd/spl/sys/uio.h
+++ b/include/os/freebsd/spl/sys/uio.h
@@ -62,7 +62,7 @@ zfs_uio_setoffset(zfs_uio_t *uio, offset_t off)
 }
 
 static inline void
-zfs_uio_advance(zfs_uio_t *uio, size_t size)
+zfs_uio_advance(zfs_uio_t *uio, ssize_t size)
 {
 	zfs_uio_resid(uio) -= size;
 	zfs_uio_offset(uio) += size;
diff --git a/include/os/linux/spl/sys/uio.h b/include/os/linux/spl/sys/uio.h
index a4b600004c9f..5e6ea8d3c221 100644
--- a/include/os/linux/spl/sys/uio.h
+++ b/include/os/linux/spl/sys/uio.h
@@ -95,7 +95,7 @@ zfs_uio_setoffset(zfs_uio_t *uio, offset_t off)
 }
 
 static inline void
-zfs_uio_advance(zfs_uio_t *uio, size_t size)
+zfs_uio_advance(zfs_uio_t *uio, ssize_t size)
 {
 	uio->uio_resid -= size;
 	uio->uio_loffset += size;
diff --git a/include/sys/dbuf.h b/include/sys/dbuf.h
index 2ff0bc72b270..3808a04cba80 100644
--- a/include/sys/dbuf.h
+++ b/include/sys/dbuf.h
@@ -380,8 +380,8 @@ dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level,
 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
 void dmu_buf_will_clone(dmu_buf_t *db, dmu_tx_t *tx);
 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
-void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
-void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
+void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx, boolean_t canfail);
+boolean_t dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx, boolean_t failed);
 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
 dbuf_dirty_record_t *dbuf_dirty_lightweight(dnode_t *dn, uint64_t blkid,
diff --git a/lib/libspl/include/sys/uio.h b/lib/libspl/include/sys/uio.h
index e9e21819d4f8..665bfc42301b 100644
--- a/lib/libspl/include/sys/uio.h
+++ b/lib/libspl/include/sys/uio.h
@@ -90,7 +90,7 @@ zfs_uio_iov_at_index(zfs_uio_t *uio, uint_t idx, void **base, uint64_t *len)
 }
 
 static inline void
-zfs_uio_advance(zfs_uio_t *uio, size_t size)
+zfs_uio_advance(zfs_uio_t *uio, ssize_t size)
 {
 	uio->uio_resid -= size;
 	uio->uio_loffset += size;
diff --git a/module/os/freebsd/zfs/dmu_os.c b/module/os/freebsd/zfs/dmu_os.c
index ee6fb2dc657b..48ea37cbad59 100644
--- a/module/os/freebsd/zfs/dmu_os.c
+++ b/module/os/freebsd/zfs/dmu_os.c
@@ -107,7 +107,7 @@ dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
 
 		if (tocpy == db->db_size)
-			dmu_buf_will_fill(db, tx);
+			dmu_buf_will_fill(db, tx, B_FALSE);
 		else
 			dmu_buf_will_dirty(db, tx);
 
@@ -123,7 +123,7 @@ dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 		}
 
 		if (tocpy == db->db_size)
-			dmu_buf_fill_done(db, tx);
+			dmu_buf_fill_done(db, tx, B_FALSE);
 
 		offset += tocpy;
 		size -= tocpy;
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index c5ccd4cd1e0c..42d5a527dc64 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -2749,7 +2749,7 @@ dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
 }
 
 void
-dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
+dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx, boolean_t canfail)
 {
 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
 
@@ -2767,8 +2767,14 @@ dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx)
 		 * Block cloning: We will be completely overwriting a block
 		 * cloned in this transaction group, so let's undirty the
 		 * pending clone and mark the block as uncached. This will be
-		 * as if the clone was never done.
+		 * as if the clone was never done.  But if the fill can fail
+		 * we should have a way to return back to the cloned data.
 		 */
+		if (canfail && dbuf_find_dirty_eq(db, tx->tx_txg) != NULL) {
+			mutex_exit(&db->db_mtx);
+			dmu_buf_will_dirty(db_fake, tx);
+			return;
+		}
 		VERIFY(!dbuf_undirty(db, tx));
 		db->db_state = DB_UNCACHED;
 	}
@@ -2829,32 +2835,41 @@ dbuf_override_impl(dmu_buf_impl_t *db, const blkptr_t *bp, dmu_tx_t *tx)
 	dl->dr_overridden_by.blk_birth = dr->dr_txg;
 }
 
-void
-dmu_buf_fill_done(dmu_buf_t *dbuf, dmu_tx_t *tx)
+boolean_t
+dmu_buf_fill_done(dmu_buf_t *dbuf, dmu_tx_t *tx, boolean_t failed)
 {
 	(void) tx;
 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
-	dbuf_states_t old_state;
 	mutex_enter(&db->db_mtx);
 	DBUF_VERIFY(db);
 
-	old_state = db->db_state;
-	db->db_state = DB_CACHED;
-	if (old_state == DB_FILL) {
+	if (db->db_state == DB_FILL) {
 		if (db->db_level == 0 && db->db_freed_in_flight) {
 			ASSERT(db->db_blkid != DMU_BONUS_BLKID);
 			/* we were freed while filling */
 			/* XXX dbuf_undirty? */
 			memset(db->db.db_data, 0, db->db.db_size);
 			db->db_freed_in_flight = FALSE;
+			db->db_state = DB_CACHED;
 			DTRACE_SET_STATE(db,
 			    "fill done handling freed in flight");
+			failed = B_FALSE;
+		} else if (failed) {
+			VERIFY(!dbuf_undirty(db, tx));
+			db->db_buf = NULL;
+			dbuf_clear_data(db);
+			DTRACE_SET_STATE(db, "fill failed");
 		} else {
+			db->db_state = DB_CACHED;
 			DTRACE_SET_STATE(db, "fill done");
 		}
 		cv_broadcast(&db->db_changed);
+	} else {
+		db->db_state = DB_CACHED;
+		failed = B_FALSE;
 	}
 	mutex_exit(&db->db_mtx);
+	return (failed);
 }
 
 void
@@ -2989,7 +3004,7 @@ dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
 	DTRACE_SET_STATE(db, "filling assigned arcbuf");
 	mutex_exit(&db->db_mtx);
 	(void) dbuf_dirty(db, tx);
-	dmu_buf_fill_done(&db->db, tx);
+	dmu_buf_fill_done(&db->db, tx, B_FALSE);
 }
 
 void
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index f5a5d0fc437f..d82211e6d4c7 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -1134,14 +1134,14 @@ dmu_write_impl(dmu_buf_t **dbp, int numbufs, uint64_t offset, uint64_t size,
 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
 
 		if (tocpy == db->db_size)
-			dmu_buf_will_fill(db, tx);
+			dmu_buf_will_fill(db, tx, B_FALSE);
 		else
 			dmu_buf_will_dirty(db, tx);
 
 		(void) memcpy((char *)db->db_data + bufoff, buf, tocpy);
 
 		if (tocpy == db->db_size)
-			dmu_buf_fill_done(db, tx);
+			dmu_buf_fill_done(db, tx, B_FALSE);
 
 		offset += tocpy;
 		size -= tocpy;
@@ -1349,27 +1349,24 @@ dmu_write_uio_dnode(dnode_t *dn, zfs_uio_t *uio, uint64_t size, dmu_tx_t *tx)
 
 		ASSERT(size > 0);
 
-		bufoff = zfs_uio_offset(uio) - db->db_offset;
+		offset_t off = zfs_uio_offset(uio);
+		bufoff = off - db->db_offset;
 		tocpy = MIN(db->db_size - bufoff, size);
 
 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
 
 		if (tocpy == db->db_size)
-			dmu_buf_will_fill(db, tx);
+			dmu_buf_will_fill(db, tx, B_TRUE);
 		else
 			dmu_buf_will_dirty(db, tx);
 
-		/*
-		 * XXX zfs_uiomove could block forever (eg.nfs-backed
-		 * pages).  There needs to be a uiolockdown() function
-		 * to lock the pages in memory, so that zfs_uiomove won't
-		 * block.
-		 */
 		err = zfs_uio_fault_move((char *)db->db_data + bufoff,
 		    tocpy, UIO_WRITE, uio);
 
-		if (tocpy == db->db_size)
-			dmu_buf_fill_done(db, tx);
+		if (tocpy == db->db_size && dmu_buf_fill_done(db, tx, err)) {
+			/* The fill was reverted.  Undo any uio progress. */
+			zfs_uio_advance(uio, off - zfs_uio_offset(uio));
+		}
 
 		if (err)
 			break;
diff --git a/module/zfs/dmu_recv.c b/module/zfs/dmu_recv.c
index 05ca91717c2f..54aa60259ea1 100644
--- a/module/zfs/dmu_recv.c
+++ b/module/zfs/dmu_recv.c
@@ -2532,7 +2532,7 @@ receive_spill(struct receive_writer_arg *rwa, struct drr_spill *drrs,
 	 * size of the provided arc_buf_t.
 	 */
 	if (db_spill->db_size != drrs->drr_length) {
-		dmu_buf_will_fill(db_spill, tx);
+		dmu_buf_will_fill(db_spill, tx, B_FALSE);
 		VERIFY0(dbuf_spill_set_blksz(db_spill,
 		    drrs->drr_length, tx));
 	}
diff --git a/module/zfs/dsl_bookmark.c b/module/zfs/dsl_bookmark.c
index 03d9420dbdb9..4faefecbadbb 100644
--- a/module/zfs/dsl_bookmark.c
+++ b/module/zfs/dsl_bookmark.c
@@ -490,7 +490,7 @@ dsl_bookmark_create_sync_impl_snap(const char *bookmark, const char *snapshot,
 			dmu_buf_t *db;
 			VERIFY0(dmu_spill_hold_by_bonus(local_rl->rl_bonus,
 			    DB_RF_MUST_SUCCEED, FTAG, &db));
-			dmu_buf_will_fill(db, tx);
+			dmu_buf_will_fill(db, tx, B_FALSE);
 			VERIFY0(dbuf_spill_set_blksz(db, P2ROUNDUP(bonuslen,
 			    SPA_MINBLOCKSIZE), tx));
 			local_rl->rl_phys = db->db_data;