diff options
| -rw-r--r-- | mm/shmem.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 404e53bb212..253d205914b 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -915,6 +915,21 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) struct inode *inode; BUG_ON(!PageLocked(page)); + /* + * shmem_backing_dev_info's capabilities prevent regular writeback or + * sync from ever calling shmem_writepage; but a stacking filesystem + * may use the ->writepage of its underlying filesystem, in which case + * we want to do nothing when that underlying filesystem is tmpfs + * (writing out to swap is useful as a response to memory pressure, but + * of no use to stabilize the data) - just redirty the page, unlock it + * and claim success in this case. AOP_WRITEPAGE_ACTIVATE, and the + * page_mapped check below, must be avoided unless we're in reclaim. + */ + if (!wbc->for_reclaim) { + set_page_dirty(page); + unlock_page(page); + return 0; + } BUG_ON(page_mapped(page)); mapping = page->mapping; |