fs: hugetlbfs: support poisoned recover from hugetlbfs_migrate_folio()

This is similar to __migrate_folio(), use folio_mc_copy() in HugeTLB folio
migration to avoid panic when copy from poisoned folio.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kefeng Wang <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Benjamin LaHaise <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jane Chu <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Jiaqi Yan <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Vishal Moola (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Kefeng Wang

fs/hugetlbfs/inode.c

@@ -1128,7 +1128,7 @@ static int hugetlbfs_migrate_folio(struct address_space *mapping,
 		hugetlb_set_folio_subpool(src, NULL);
 	}
 
-	folio_migrate_copy(dst, src);
+	folio_migrate_flags(dst, src);
 
 	return MIGRATEPAGE_SUCCESS;
 }

mm/migrate.c

@@ -550,10 +550,16 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
 				   struct folio *dst, struct folio *src)
 {
 	XA_STATE(xas, &mapping->i_pages, folio_index(src));
-	int expected_count;
+	int rc, expected_count = folio_expected_refs(mapping, src);
+
+	if (folio_ref_count(src) != expected_count)
+		return -EAGAIN;
+
+	rc = folio_mc_copy(dst, src);
+	if (unlikely(rc))
+		return rc;
 
 	xas_lock_irq(&xas);
-	expected_count = folio_expected_refs(mapping, src);
 	if (!folio_ref_freeze(src, expected_count)) {
 		xas_unlock_irq(&xas);
 		return -EAGAIN;