shmem-fallocate.patch

diff --git a/mm/shmem.c b/mm/shmem.c
index e4c9e5c7081f..1fb3f69e19e2 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -959,11 +959,13 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 	folio = shmem_get_partial_folio(inode, lstart >> PAGE_SHIFT);
 	if (folio) {
 		same_folio = lend < folio_pos(folio) + folio_size(folio);
-		folio_mark_dirty(folio);
-		if (!truncate_inode_partial_folio(folio, lstart, lend)) {
-			start = folio->index + folio_nr_pages(folio);
-			if (same_folio)
-				end = folio->index;
+		if (!unfalloc || !folio_test_uptodate(folio)) {
+			folio_mark_dirty(folio);
+			if (!truncate_inode_partial_folio(folio, lstart, lend)) {
+				start = folio->index + folio_nr_pages(folio);
+				if (same_folio)
+					end = folio->index;
+			}
 		}
 		folio_unlock(folio);
 		folio_put(folio);
@@ -973,9 +975,11 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 	if (!same_folio)
 		folio = shmem_get_partial_folio(inode, lend >> PAGE_SHIFT);
 	if (folio) {
-		folio_mark_dirty(folio);
-		if (!truncate_inode_partial_folio(folio, lstart, lend))
-			end = folio->index;
+		if (!unfalloc || !folio_test_uptodate(folio)) {
+			folio_mark_dirty(folio);
+			if (!truncate_inode_partial_folio(folio, lstart, lend))
+				end = folio->index;
+		}
 		folio_unlock(folio);
 		folio_put(folio);
 	}