From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755427Ab1D0PAh (ORCPT ); Wed, 27 Apr 2011 11:00:37 -0400 Received: from moutng.kundenserver.de ([212.227.17.9]:61384 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753535Ab1D0PAg (ORCPT ); Wed, 27 Apr 2011 11:00:36 -0400 From: Arnd Bergmann To: Andrea Righi Subject: Re: [PATCH] fadvise: introduce POSIX_FADV_DONTNEED_FS Date: Wed, 27 Apr 2011 17:00:12 +0200 User-Agent: KMail/1.13.5 (Linux/2.6.39-rc4+; KDE/4.5.1; x86_64; ; ) Cc: Andrew Morton , Dave Chinner , Mike Frysinger , Al Viro , linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org References: <1303914545-15642-1-git-send-email-andrea@betterlinux.com> In-Reply-To: <1303914545-15642-1-git-send-email-andrea@betterlinux.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <201104271700.13013.arnd@arndb.de> X-Provags-ID: V02:K0:28N9cDVU7fbqx9edhUDPZVnYjycu9RbZqVW0f4Wc8y8 3bOJqHeiQCNO8HUtvbaFBNukbzHlCw0kRwrF04M59Ae3rAixXv Vbw7Wzltu6utSJiuY5Hy5nE1Ik28umoK1al1bDHWA2DjbYTRzF UINwsLirQ7kyuth5YgZd4Vgd8mhSLwaweaz3zKTa9jmMvW5oTg 1I504UvFI2KcrLULrwWPQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 27 April 2011 16:29:05 Andrea Righi wrote: > diff --git a/include/linux/fadvise.h b/include/linux/fadvise.h > index e8e7471..dc9ce98 100644 > --- a/include/linux/fadvise.h > +++ b/include/linux/fadvise.h > @@ -13,9 +13,11 @@ > #if defined(__s390x__) > #define POSIX_FADV_DONTNEED 6 /* Don't need these pages. */ > #define POSIX_FADV_NOREUSE 7 /* Data will be accessed once. */ > +#define POSIX_FADV_DONTNEED_FS 8 /* Don't need these filesystem pages. */ > #else > #define POSIX_FADV_DONTNEED 4 /* Don't need these pages. */ > #define POSIX_FADV_NOREUSE 5 /* Data will be accessed once. */ > +#define POSIX_FADV_DONTNEED_FS 6 /* Don't need these filesystem pages. */ > #endif > > #endif /* FADVISE_H_INCLUDED */ Please don't make the s390 mess worse than it already is here. I think the best solution would be to assign new values starting from 8 so they can be common for all architectures. > @@ -127,6 +128,12 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) > invalidate_mapping_pages(mapping, start_index, > end_index); > break; > + case POSIX_FADV_DONTNEED_FS: > + if (!current_euid()) > + drop_pagecache_sb(file->f_dentry->d_sb, NULL); > + else > + ret = -EPERM; > + break; I somewhat disagree with keying the capability off the UID value, even if that is what the sysctl uses. CAP_SYS_ADMIN is not that nice either, but I think it's better than the UID here. Aside from these, I like the patch. Arnd