diff --git a/include/os/linux/zfs/sys/zfs_vfsops_os.h b/include/os/linux/zfs/sys/zfs_vfsops_os.h
index 220466550258..55be253ffbff 100644
--- a/include/os/linux/zfs/sys/zfs_vfsops_os.h
+++ b/include/os/linux/zfs/sys/zfs_vfsops_os.h
@@ -46,6 +46,7 @@ typedef struct zfsvfs zfsvfs_t;
 struct znode;
 
 extern int zfs_bclone_enabled;
+extern int zfs_bclone_wait_dirty;
 
 /*
  * This structure emulates the vfs_t from other platforms.  It's purpose
diff --git a/man/man4/zfs.4 b/man/man4/zfs.4
index 47471a805907..30c168253f96 100644
--- a/man/man4/zfs.4
+++ b/man/man4/zfs.4
@@ -1159,6 +1159,15 @@ Enable the experimental block cloning feature.
 If this setting is 0, then even if feature@block_cloning is enabled,
 attempts to clone blocks will act as though the feature is disabled.
 .
+.It Sy zfs_bclone_wait_dirty Ns = Ns Sy 0 Ns | Ns 1 Pq int
+When set to 1 the FICLONE and FICLONERANGE ioctls wait for dirty data to be
+written to disk.
+This allows the clone operation to reliably succeed when a file is
+modified and then immediately cloned.
+For small files this may be slower than making a copy of the file.
+Therefore, this setting defaults to 0 which causes a clone operation to
+immediately fail when encountering a dirty block.
+.
 .It Sy zfs_blake3_impl Ns = Ns Sy fastest Pq string
 Select a BLAKE3 implementation.
 .Pp
diff --git a/module/os/freebsd/zfs/zfs_vfsops.c b/module/os/freebsd/zfs/zfs_vfsops.c
index f2d5391037c4..b730bcb9509d 100644
--- a/module/os/freebsd/zfs/zfs_vfsops.c
+++ b/module/os/freebsd/zfs/zfs_vfsops.c
@@ -93,6 +93,10 @@ int zfs_bclone_enabled = 1;
 SYSCTL_INT(_vfs_zfs, OID_AUTO, bclone_enabled, CTLFLAG_RWTUN,
 	&zfs_bclone_enabled, 0, "Enable block cloning");
 
+int zfs_bclone_wait_dirty = 0;
+SYSCTL_INT(_vfs_zfs, OID_AUTO, bclone_wait_dirty, CTLFLAG_RWTUN,
+	&zfs_bclone_wait_dirty, 0, "Wait for dirty blocks when cloning");
+
 struct zfs_jailparam {
 	int mount_snapshot;
 };
diff --git a/module/os/linux/zfs/zfs_vnops_os.c b/module/os/linux/zfs/zfs_vnops_os.c
index b7b89b8afc56..4b9bfd71e926 100644
--- a/module/os/linux/zfs/zfs_vnops_os.c
+++ b/module/os/linux/zfs/zfs_vnops_os.c
@@ -4257,7 +4257,11 @@ module_param(zfs_delete_blocks, ulong, 0644);
 MODULE_PARM_DESC(zfs_delete_blocks, "Delete files larger than N blocks async");
 
 /* CSTYLED */
-module_param(zfs_bclone_enabled, uint, 0644);
+module_param(zfs_bclone_enabled, int, 0644);
 MODULE_PARM_DESC(zfs_bclone_enabled, "Enable block cloning");
 
+/* CSTYLED */
+module_param(zfs_bclone_wait_dirty, int, 0644);
+MODULE_PARM_DESC(zfs_bclone_wait_dirty, "Wait for dirty blocks when cloning");
+
 #endif
diff --git a/module/os/linux/zfs/zpl_file_range.c b/module/os/linux/zfs/zpl_file_range.c
index 73476ff40ebf..0682e84768e3 100644
--- a/module/os/linux/zfs/zpl_file_range.c
+++ b/module/os/linux/zfs/zpl_file_range.c
@@ -32,6 +32,7 @@
 #include <sys/zfeature.h>
 
 int zfs_bclone_enabled = 1;
+int zfs_bclone_wait_dirty = 0;
 
 /*
  * Clone part of a file via block cloning.
@@ -40,7 +41,7 @@ int zfs_bclone_enabled = 1;
  * care of that depending on how it was called.
  */
 static ssize_t
-__zpl_clone_file_range(struct file *src_file, loff_t src_off,
+zpl_clone_file_range_impl(struct file *src_file, loff_t src_off,
     struct file *dst_file, loff_t dst_off, size_t len)
 {
 	struct inode *src_i = file_inode(src_file);
@@ -96,11 +97,12 @@ zpl_copy_file_range(struct file *src_file, loff_t src_off,
 {
 	ssize_t ret;
 
+	/* Flags is reserved for future extensions and must be zero. */
 	if (flags != 0)
 		return (-EINVAL);
 
-	/* Try to do it via zfs_clone_range() */
-	ret = __zpl_clone_file_range(src_file, src_off,
+	/* Try to do it via zfs_clone_range() and allow shortening. */
+	ret = zpl_clone_file_range_impl(src_file, src_off,
 	    dst_file, dst_off, len);
 
 #ifdef HAVE_VFS_GENERIC_COPY_FILE_RANGE
@@ -137,6 +139,11 @@ zpl_copy_file_range(struct file *src_file, loff_t src_off,
  * FIDEDUPERANGE is for turning a non-clone into a clone, that is, compare the
  * range in both files and if they're the same, arrange for them to be backed
  * by the same storage.
+ *
+ * REMAP_FILE_CAN_SHORTEN lets us know we can clone less than the given range
+ * if we want. It's designed for filesystems that may need to shorten the
+ * length for alignment, EOF, or any other requirement. ZFS may shorten the
+ * request when there is outstanding dirty data which hasn't been written.
  */
 loff_t
 zpl_remap_file_range(struct file *src_file, loff_t src_off,
@@ -145,24 +152,21 @@ zpl_remap_file_range(struct file *src_file, loff_t src_off,
 	if (flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_CAN_SHORTEN))
 		return (-EINVAL);
 
-	/*
-	 * REMAP_FILE_CAN_SHORTEN lets us know we can clone less than the given
-	 * range if we want. Its designed for filesystems that make data past
-	 * EOF available, and don't want it to be visible in both files. ZFS
-	 * doesn't do that, so we just turn the flag off.
-	 */
-	flags &= ~REMAP_FILE_CAN_SHORTEN;
-
+	/* No support for dedup yet */
 	if (flags & REMAP_FILE_DEDUP)
-		/* No support for dedup yet */
 		return (-EOPNOTSUPP);
 
 	/* Zero length means to clone everything to the end of the file */
 	if (len == 0)
 		len = i_size_read(file_inode(src_file)) - src_off;
 
-	return (__zpl_clone_file_range(src_file, src_off,
-	    dst_file, dst_off, len));
+	ssize_t ret = zpl_clone_file_range_impl(src_file, src_off,
+	    dst_file, dst_off, len);
+
+	if (!(flags & REMAP_FILE_CAN_SHORTEN) && ret >= 0 && ret != len)
+		ret = -EINVAL;
+
+	return (ret);
 }
 #endif /* HAVE_VFS_REMAP_FILE_RANGE */
 
@@ -179,8 +183,14 @@ zpl_clone_file_range(struct file *src_file, loff_t src_off,
 	if (len == 0)
 		len = i_size_read(file_inode(src_file)) - src_off;
 
-	return (__zpl_clone_file_range(src_file, src_off,
-	    dst_file, dst_off, len));
+	/* The entire length must be cloned or this is an error. */
+	ssize_t ret = zpl_clone_file_range_impl(src_file, src_off,
+	    dst_file, dst_off, len);
+
+	if (ret >= 0 && ret != len)
+		ret = -EINVAL;
+
+	return (ret);
 }
 #endif /* HAVE_VFS_CLONE_FILE_RANGE || HAVE_VFS_FILE_OPERATIONS_EXTEND */
 
@@ -214,8 +224,7 @@ zpl_ioctl_ficlone(struct file *dst_file, void *arg)
 
 	size_t len = i_size_read(file_inode(src_file));
 
-	ssize_t ret =
-	    __zpl_clone_file_range(src_file, 0, dst_file, 0, len);
+	ssize_t ret = zpl_clone_file_range_impl(src_file, 0, dst_file, 0, len);
 
 	fput(src_file);
 
@@ -253,7 +262,7 @@ zpl_ioctl_ficlonerange(struct file *dst_file, void __user *arg)
 	if (len == 0)
 		len = i_size_read(file_inode(src_file)) - fcr.fcr_src_offset;
 
-	ssize_t ret = __zpl_clone_file_range(src_file, fcr.fcr_src_offset,
+	ssize_t ret = zpl_clone_file_range_impl(src_file, fcr.fcr_src_offset,
 	    dst_file, fcr.fcr_dest_offset, len);
 
 	fput(src_file);
diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index c8ff7b6432fd..9c7929ad22f5 100644
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -1049,6 +1049,7 @@ zfs_clone_range(znode_t *inzp, uint64_t *inoffp, znode_t *outzp,
 	size_t		maxblocks, nbps;
 	uint_t		inblksz;
 	uint64_t	clear_setid_bits_txg = 0;
+	uint64_t	last_synced_txg = 0;
 
 	inoff = *inoffp;
 	outoff = *outoffp;
@@ -1287,15 +1288,23 @@ zfs_clone_range(znode_t *inzp, uint64_t *inoffp, znode_t *outzp,
 		}
 
 		nbps = maxblocks;
+		last_synced_txg = spa_last_synced_txg(dmu_objset_spa(inos));
 		error = dmu_read_l0_bps(inos, inzp->z_id, inoff, size, bps,
 		    &nbps);
 		if (error != 0) {
 			/*
 			 * If we are trying to clone a block that was created
-			 * in the current transaction group, error will be
-			 * EAGAIN here, which we can just return to the caller
-			 * so it can fallback if it likes.
+			 * in the current transaction group, the error will be
+			 * EAGAIN here.  Based on sync_wait either return a
+			 * shortened range to the caller so it can fallback,
+			 * or wait for the next sync and check again.
 			 */
+			if (error == EAGAIN && zfs_bclone_wait_dirty) {
+				txg_wait_synced(dmu_objset_pool(inos),
+				    last_synced_txg + 1);
+				continue;
+			}
+
 			break;
 		}
 
diff --git a/tests/runfiles/common.run b/tests/runfiles/common.run
index 7e0990b5d9f9..05e8cdc8f234 100644
--- a/tests/runfiles/common.run
+++ b/tests/runfiles/common.run
@@ -631,7 +631,7 @@ tests = ['compress_001_pos', 'compress_002_pos', 'compress_003_pos',
 tags = ['functional', 'compression']
 
 [tests/functional/cp_files]
-tests = ['cp_files_001_pos', 'cp_stress']
+tests = ['cp_files_001_pos', 'cp_files_002_pos', 'cp_stress']
 tags = ['functional', 'cp_files']
 
 [tests/functional/crtime]
diff --git a/tests/test-runner/bin/zts-report.py.in b/tests/test-runner/bin/zts-report.py.in
index ae4aa6275465..27c0d3e6c209 100755
--- a/tests/test-runner/bin/zts-report.py.in
+++ b/tests/test-runner/bin/zts-report.py.in
@@ -176,6 +176,7 @@ if sys.platform.startswith('freebsd'):
         'cli_root/zpool_wait/zpool_wait_trim_cancel': ['SKIP', trim_reason],
         'cli_root/zpool_wait/zpool_wait_trim_flag': ['SKIP', trim_reason],
         'cli_root/zfs_unshare/zfs_unshare_008_pos': ['SKIP', na_reason],
+        'cp_files/cp_files_002_pos': ['SKIP', na_reason],
         'link_count/link_count_001': ['SKIP', na_reason],
         'casenorm/mixed_create_failure': ['FAIL', 13215],
         'mmap/mmap_sync_001_pos': ['SKIP', na_reason],
diff --git a/tests/zfs-tests/include/tunables.cfg b/tests/zfs-tests/include/tunables.cfg
index e4e380aa7fd5..a619b846dd11 100644
--- a/tests/zfs-tests/include/tunables.cfg
+++ b/tests/zfs-tests/include/tunables.cfg
@@ -94,6 +94,7 @@ VOL_MODE			vol.mode			zvol_volmode
 VOL_RECURSIVE			vol.recursive			UNSUPPORTED
 VOL_USE_BLK_MQ			UNSUPPORTED			zvol_use_blk_mq
 BCLONE_ENABLED			zfs_bclone_enabled		zfs_bclone_enabled
+BCLONE_WAIT_DIRTY		zfs_bclone_wait_dirty		zfs_bclone_wait_dirty
 XATTR_COMPAT			xattr_compat			zfs_xattr_compat
 ZEVENT_LEN_MAX			zevent.len_max			zfs_zevent_len_max
 ZEVENT_RETAIN_MAX		zevent.retain_max		zfs_zevent_retain_max
diff --git a/tests/zfs-tests/tests/Makefile.am b/tests/zfs-tests/tests/Makefile.am
index 4040e60434a7..44fa0bf6869c 100644
--- a/tests/zfs-tests/tests/Makefile.am
+++ b/tests/zfs-tests/tests/Makefile.am
@@ -1394,6 +1394,7 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/compression/setup.ksh \
 	functional/cp_files/cleanup.ksh \
 	functional/cp_files/cp_files_001_pos.ksh \
+	functional/cp_files/cp_files_002_pos.ksh \
 	functional/cp_files/cp_stress.ksh \
 	functional/cp_files/setup.ksh \
 	functional/crtime/cleanup.ksh \
diff --git a/tests/zfs-tests/tests/functional/cp_files/cp_files_002_pos.ksh b/tests/zfs-tests/tests/functional/cp_files/cp_files_002_pos.ksh
new file mode 100755
index 000000000000..03719bf56706
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/cp_files/cp_files_002_pos.ksh
@@ -0,0 +1,159 @@
+#! /bin/ksh -p
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or https://opensource.org/licenses/CDDL-1.0.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2024 by Lawrence Livermore National Security, LLC.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+#
+# DESCRIPTION:
+# Verify all cp --reflink modes work with modified file.
+#
+# STRATEGY:
+# 1. Verify "cp --reflink=never|auto|always" behaves as expected.
+#    Two different modes of operation are tested.
+#
+#    a. zfs_bclone_wait_dirty=0: FICLONE and FICLONERANGE fail with EINVAL
+#       when there are dirty blocks which cannot be immediately cloned.
+#       This is the default behavior.
+#
+#    b. zfs_bclone_wait_dirty=1: FICLONE and FICLONERANGE wait for
+#       dirty blocks to be written to disk allowing the clone to succeed.
+#       The downside to this is it may be slow which depending on the
+#       situtation may defeat the point of making a clone.
+#
+
+verify_runnable "global"
+
+if ! is_linux; then
+	log_unsupported "cp --reflink is a GNU coreutils option"
+fi
+
+function cleanup
+{
+	datasetexists $TESTPOOL/cp-reflink && \
+	    destroy_dataset $$TESTPOOL/cp-reflink -f
+	log_must set_tunable32 BCLONE_WAIT_DIRTY 0
+}
+
+function verify_copy
+{
+	src_cksum=$(sha256digest $1)
+	dst_cksum=$(sha256digest $2)
+
+	if [[ "$src_cksum" != "$dst_cksum" ]]; then
+		log_must ls -l $CP_TESTDIR
+		log_fail "checksum mismatch ($src_cksum != $dst_cksum)"
+	fi
+}
+
+log_assert "Verify all cp --reflink modes work with modified file"
+
+log_onexit cleanup
+
+SRC_FILE=src.data
+DST_FILE=dst.data
+SRC_SIZE=$(($RANDOM % 2048))
+
+# A smaller recordsize is used merely to speed up the test.
+RECORDSIZE=4096
+
+log_must zfs create -o recordsize=$RECORDSIZE $TESTPOOL/cp-reflink
+CP_TESTDIR=$(get_prop mountpoint $TESTPOOL/cp-reflink)
+
+log_must cd $CP_TESTDIR
+
+# Never wait on dirty blocks (zfs_bclone_wait_dirty=0)
+log_must set_tunable32 BCLONE_WAIT_DIRTY 0
+
+for mode in "never" "auto" "always"; do
+	log_note "Checking 'cp --reflink=$mode'"
+
+	# Create a new file and immediately copy it.
+	log_must dd if=/dev/urandom of=$SRC_FILE bs=$RECORDSIZE count=$SRC_SIZE
+
+	if [[ "$mode" == "always" ]]; then
+		log_mustnot cp --reflink=$mode $SRC_FILE $DST_FILE
+		log_must ls -l $CP_TESTDIR
+	else
+		log_must cp --reflink=$mode $SRC_FILE $DST_FILE
+		verify_copy $SRC_FILE $DST_FILE
+	fi
+	log_must rm -f $DST_FILE
+
+	# Append to an existing file and immediately copy it.
+	sync_pool $TESTPOOL
+	log_must dd if=/dev/urandom of=$SRC_FILE bs=$RECORDSIZE seek=$SRC_SIZE \
+	    count=1 conv=notrunc
+	if [[ "$mode" == "always" ]]; then
+		log_mustnot cp --reflink=$mode $SRC_FILE $DST_FILE
+		log_must ls -l $CP_TESTDIR
+	else
+		log_must cp --reflink=$mode $SRC_FILE $DST_FILE
+		verify_copy $SRC_FILE $DST_FILE
+	fi
+	log_must rm -f $DST_FILE
+
+	# Overwrite a random range of an existing file and immediately copy it.
+	sync_pool $TESTPOOL
+	log_must dd if=/dev/urandom of=$SRC_FILE bs=$((RECORDSIZE / 2)) \
+            seek=$(($RANDOM % $SRC_SIZE)) count=$(($RANDOM % 16)) conv=notrunc
+	if [[ "$mode" == "always" ]]; then
+		log_mustnot cp --reflink=$mode $SRC_FILE $DST_FILE
+		log_must ls -l $CP_TESTDIR
+	else
+		log_must cp --reflink=$mode $SRC_FILE $DST_FILE
+		verify_copy $SRC_FILE $DST_FILE
+	fi
+	log_must rm -f $SRC_FILE $DST_FILE
+done
+
+# Wait on dirty blocks (zfs_bclone_wait_dirty=1)
+log_must set_tunable32 BCLONE_WAIT_DIRTY 1
+
+for mode in "never" "auto" "always"; do
+	log_note "Checking 'cp --reflink=$mode'"
+
+	# Create a new file and immediately copy it.
+	log_must dd if=/dev/urandom of=$SRC_FILE bs=$RECORDSIZE count=$SRC_SIZE
+	log_must cp --reflink=$mode $SRC_FILE $DST_FILE
+	verify_copy $SRC_FILE $DST_FILE
+	log_must rm -f $DST_FILE
+
+	# Append to an existing file and immediately copy it.
+	log_must dd if=/dev/urandom of=$SRC_FILE bs=$RECORDSIZE seek=$SRC_SIZE \
+	    count=1 conv=notrunc
+	log_must cp --reflink=$mode $SRC_FILE $DST_FILE
+	verify_copy $SRC_FILE $DST_FILE
+	log_must rm -f $DST_FILE
+
+	# Overwrite a random range of an existing file and immediately copy it.
+	log_must dd if=/dev/urandom of=$SRC_FILE bs=$((RECORDSIZE / 2)) \
+            seek=$(($RANDOM % $SRC_SIZE)) count=$(($RANDOM % 16)) conv=notrunc
+	log_must cp --reflink=$mode $SRC_FILE $DST_FILE
+	verify_copy $SRC_FILE $DST_FILE
+	log_must rm -f $SRC_FILE $DST_FILE
+done
+
+log_pass