[PATCH v3 4/5] fs: hugetlbfs: support poison recover from hugetlbfs_migrate_folio()

[Kefeng Wang <wangkefeng.wang@huawei.com>]

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

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 fs/hugetlbfs/inode.c |  2 +-
 mm/migrate.c         | 13 ++++++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 6df794ed4066..1107e5aa8343 100644
--- a/fs/hugetlbfs/inode.c
+++ b/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;
 }
diff --git a/mm/migrate.c b/mm/migrate.c
index e8acc6c38574..78cfad677789 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -532,15 +532,18 @@ 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 expected_count = folio_expected_refs(mapping, src);
 
-	xas_lock_irq(&xas);
-	expected_count = folio_expected_refs(mapping, src);
-	if (!folio_ref_freeze(src, expected_count)) {
-		xas_unlock_irq(&xas);
+	if (!folio_ref_freeze(src, expected_count))
 		return -EAGAIN;
+
+	if (unlikely(folio_mc_copy(dst, src))) {
+		folio_ref_unfreeze(src, expected_count);
+		return -EFAULT;
 	}
 
+	xas_lock_irq(&xas);
+
 	dst->index = src->index;
 	dst->mapping = src->mapping;
 
-- 
2.27.0