diff options
| -rw-r--r-- | mm/vmscan.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 557ad1367595..da431c5edae5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1374,6 +1374,7 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode) if (PageDirty(page)) { struct address_space *mapping; + bool migrate_dirty; /* ISOLATE_CLEAN means only clean pages */ if (mode & ISOLATE_CLEAN) @@ -1382,10 +1383,19 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode) /* * Only pages without mappings or that have a * ->migratepage callback are possible to migrate - * without blocking + * without blocking. However, we can be racing with + * truncation so it's necessary to lock the page + * to stabilise the mapping as truncation holds + * the page lock until after the page is removed + * from the page cache. */ + if (!trylock_page(page)) + return ret; + mapping = page_mapping(page); - if (mapping && !mapping->a_ops->migratepage) + migrate_dirty = mapping && mapping->a_ops->migratepage; + unlock_page(page); + if (!migrate_dirty) return ret; } } |