diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 46c62f980c24..03c00c99099d 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -99,6 +99,12 @@ enum {
 	 * range).
 	 */
 	BTRFS_INODE_COW_WRITE_ERROR,
+	/*
+	 * Set by reflink while it holds the source's VFS inode lock shared.
+	 * Direct IO writes also take that lock shared; one that finds this bit
+	 * set after acquiring it must retry with the exclusive lock.
+	 */
+	BTRFS_INODE_REFLINK_SRC,
 	/*
 	 * Indicate this is a directory that points to a subvolume for which
 	 * there is no root reference item. That's a case like the following:
diff --git a/fs/btrfs/direct-io.c b/fs/btrfs/direct-io.c
index 3075d7992713..ed3914257d39 100644
--- a/fs/btrfs/direct-io.c
+++ b/fs/btrfs/direct-io.c
@@ -913,6 +913,13 @@ ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
 		goto relock;
 	}
 
+	if ((ilock_flags & BTRFS_ILOCK_SHARED) &&
+	    test_bit(BTRFS_INODE_REFLINK_SRC, &BTRFS_I(inode)->runtime_flags)) {
+		btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
+		ilock_flags &= ~BTRFS_ILOCK_SHARED;
+		goto relock;
+	}
+
 	ret = generic_write_checks(iocb, from);
 	if (ret <= 0) {
 		btrfs_inode_unlock(BTRFS_I(inode), ilock_flags);
diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
index 8e37706b98c3..b5d2c094941d 100644
--- a/fs/btrfs/reflink.c
+++ b/fs/btrfs/reflink.c
@@ -939,6 +939,7 @@ loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
 	struct btrfs_inode *dst_inode = BTRFS_I(file_inode(dst_file));
 	bool same_inode = dst_inode == src_inode;
 	u64 wb_start, wb_len;
+	bool src_downgraded = false;
 	int ret;
 
 	if (btrfs_is_shutdown(src_inode->root->fs_info))
@@ -976,6 +977,12 @@ loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
 	if (ret < 0 || len == 0)
 		goto out_unlock;
 
+	if (!same_inode) {
+		set_bit(BTRFS_INODE_REFLINK_SRC, &src_inode->runtime_flags);
+		downgrade_write(&src_inode->vfs_inode.i_rwsem);
+		src_downgraded = true;
+	}
+
 	if (remap_flags & REMAP_FILE_DEDUP)
 		ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff);
 	else
@@ -986,8 +993,14 @@ loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
 		btrfs_inode_unlock(src_inode, BTRFS_ILOCK_MMAP);
 	} else {
 		btrfs_double_mmap_unlock(src_inode, dst_inode);
-		unlock_two_nondirectories(&src_inode->vfs_inode,
-					  &dst_inode->vfs_inode);
+		if (src_downgraded) {
+			clear_bit(BTRFS_INODE_REFLINK_SRC, &src_inode->runtime_flags);
+			inode_unlock_shared(&src_inode->vfs_inode);
+			inode_unlock(&dst_inode->vfs_inode);
+		} else {
+			unlock_two_nondirectories(&src_inode->vfs_inode,
+						  &dst_inode->vfs_inode);
+		}
 	}
 
 	/*