1 files changed, 34 insertions, 9 deletions

diff --git a/mm/truncate.c b/mm/truncate.c
index fbe848fdc391..12467c1bd711 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -46,7 +46,7 @@ static void clear_shadow_entries(struct address_space *mapping,
 
 	xas_unlock_irq(&xas);
 	if (mapping_shrinkable(mapping))
-		inode_add_lru(mapping->host);
+		inode_lru_list_add(mapping->host);
 	spin_unlock(&mapping->host->i_lock);
 }
 
@@ -111,7 +111,7 @@ static void truncate_folio_batch_exceptionals(struct address_space *mapping,
 
 	xas_unlock_irq(&xas);
 	if (mapping_shrinkable(mapping))
-		inode_add_lru(mapping->host);
+		inode_lru_list_add(mapping->host);
 	spin_unlock(&mapping->host->i_lock);
 out:
 	folio_batch_remove_exceptionals(fbatch);
@@ -177,6 +177,32 @@ int truncate_inode_folio(struct address_space *mapping, struct folio *folio)
 	return 0;
 }
 
+static int try_folio_split_or_unmap(struct folio *folio, struct page *split_at,
+				    unsigned long min_order)
+{
+	enum ttu_flags ttu_flags =
+		TTU_SYNC |
+		TTU_SPLIT_HUGE_PMD |
+		TTU_IGNORE_MLOCK;
+	int ret;
+
+	ret = try_folio_split_to_order(folio, split_at, min_order);
+
+	/*
+	 * If the split fails, unmap the folio, so it will be refaulted
+	 * with PTEs to respect SIGBUS semantics.
+	 *
+	 * Make an exception for shmem/tmpfs that for long time
+	 * intentionally mapped with PMDs across i_size.
+	 */
+	if (ret && !shmem_mapping(folio->mapping)) {
+		try_to_unmap(folio, ttu_flags);
+		WARN_ON(folio_mapped(folio));
+	}
+
+	return ret;
+}
+
 /*
  * Handle partial folios.  The folio may be entirely within the
  * range if a split has raced with us.  If not, we zero the part of the
@@ -194,6 +220,7 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
 	size_t size = folio_size(folio);
 	unsigned int offset, length;
 	struct page *split_at, *split_at2;
+	unsigned int min_order;
 
 	if (pos < start)
 		offset = start - pos;
@@ -223,8 +250,9 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
 	if (!folio_test_large(folio))
 		return true;
 
+	min_order = mapping_min_folio_order(folio->mapping);
 	split_at = folio_page(folio, PAGE_ALIGN_DOWN(offset) / PAGE_SIZE);
-	if (!try_folio_split(folio, split_at, NULL)) {
+	if (!try_folio_split_or_unmap(folio, split_at, min_order)) {
 		/*
 		 * try to split at offset + length to make sure folios within
 		 * the range can be dropped, especially to avoid memory waste
@@ -248,13 +276,10 @@ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end)
 		if (!folio_trylock(folio2))
 			goto out;
 
-		/*
-		 * make sure folio2 is large and does not change its mapping.
-		 * Its split result does not matter here.
-		 */
+		/* make sure folio2 is large and does not change its mapping */
 		if (folio_test_large(folio2) &&
 		    folio2->mapping == folio->mapping)
-			try_folio_split(folio2, split_at2, NULL);
+			try_folio_split_or_unmap(folio2, split_at2, min_order);
 
 		folio_unlock(folio2);
 out:
@@ -622,7 +647,7 @@ int folio_unmap_invalidate(struct address_space *mapping, struct folio *folio,
 	__filemap_remove_folio(folio, NULL);
 	xa_unlock_irq(&mapping->i_pages);
 	if (mapping_shrinkable(mapping))
-		inode_add_lru(mapping->host);
+		inode_lru_list_add(mapping->host);
 	spin_unlock(&mapping->host->i_lock);
 
 	filemap_free_folio(mapping, folio);