diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ae9e4ad1949a..cade9a2d561e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -681,7 +681,11 @@ again:
 		}
 	}
 cont:
-	if (start == 0) {
+	/*
+	 * Check cow_file_range() for why we don't even try to create inline
+	 * extent for subpage case.
+	 */
+	if (start == 0 && fs_info->sectorsize == PAGE_SIZE) {
 		/* lets try to make an inline extent */
 		if (ret || total_in < actual_end) {
 			/* we didn't compress the entire range, try
@@ -1079,7 +1083,17 @@ static noinline int cow_file_range(struct btrfs_inode *inode,
 
 	inode_should_defrag(inode, start, end, num_bytes, SZ_64K);
 
-	if (start == 0) {
+	/*
+	 * Due to the page size limit, for subpage we can only trigger the
+	 * writeback for the dirty sectors of page, that means data writeback
+	 * is doing more writeback than what we want.
+	 *
+	 * This is especially unexpected for some call sites like fallocate,
+	 * where we only increase i_size after everything is done.
+	 * This means we can trigger inline extent even if we didn't want to.
+	 * So here we skip inline extent creation completely.
+	 */
+	if (start == 0 && fs_info->sectorsize == PAGE_SIZE) {
 		/* lets try to make an inline extent */
 		ret = cow_file_range_inline(inode, start, end, 0,
 					    BTRFS_COMPRESS_NONE, NULL);