mm: fix infinite loop in filemap_fault

Miklos Szeredi · torvalds · commit 3ef0f720e47e · 2008-05-14T19:11:13.000-07:00
filemap_fault will go into an infinite loop if ->readpage() fails asynchronously. AFAICS the bug was introduced by this commit, which removed the wait after the final readpage: commit d00806b Author: Nick Piggin <npiggin@suse.de> Date: Thu Jul 19 01:46:57 2007 -0700 mm: fix fault vs invalidate race for linear mappings Fix by reintroducing the wait_on_page_locked() after ->readpage() to make sure the page is up-to-date before jumping back to the beginning of the function. I've noticed this while testing nfs exporting on fuse. The patch fixes it. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/filemap.c b/mm/filemap.c
@@ -1461,6 +1461,11 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	 */
 	ClearPageError(page);
 	error = mapping->a_ops->readpage(file, page);
+	if (!error) {
+		wait_on_page_locked(page);
+		if (!PageUptodate(page))
+			error = -EIO;
+	}
 	page_cache_release(page);
 
 	if (!error || error == AOP_TRUNCATED_PAGE)
