[PATCH] smbfs readdir vs signal fix

An old patch designed to fix http://bugme.osdl.org/show_bug.cgi?id=4497,
"getdents gives empty/random result upon signal".

If smbfs's readdir() is interupted by a signal, smb_readdir() failed to
noticed that and proceeded to treat the unread-into page as valid directory
contents.  Fix that up by handling the -ERESTARTSYS.

Thanks to Stian Skjelstad for reporting and testing.

Cc: Stian Skjelstad <stian@nixia.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/smbfs/dir.c

@@ -209,6 +209,8 @@ smb_readdir(struct file *filp, void *dirent, filldir_t filldir)
 	ctl.valid  = 1;
 read_really:
 	result = server->ops->readdir(filp, dirent, filldir, &ctl);
+	if (result == -ERESTARTSYS && page)
+		ClearPageUptodate(page);
 	if (ctl.idx == -1)
 		goto invalid_cache;	/* retry */
 	ctl.head.end = ctl.fpos - 1;
@@ -217,6 +219,7 @@ smb_readdir(struct file *filp, void *dirent, filldir_t filldir)
 	if (page) {
 		cache->head = ctl.head;
 		kunmap(page);
+		if (result != -ERESTARTSYS)
 			SetPageUptodate(page);
 		unlock_page(page);
 		page_cache_release(page);