Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755626Ab2F2SHF (ORCPT ); Fri, 29 Jun 2012 14:07:05 -0400 Received: from mail.parknet.co.jp ([210.171.160.6]:39752 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753290Ab2F2SHB (ORCPT ); Fri, 29 Jun 2012 14:07:01 -0400 From: OGAWA Hirofumi To: "Steven J. Magnani" Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] fat: Fix non-atomic NFS i_pos read References: <1340990350-9565-1-git-send-email-steve@digidescorp.com> Date: Sat, 30 Jun 2012 03:06:56 +0900 In-Reply-To: <1340990350-9565-1-git-send-email-steve@digidescorp.com> (Steven J. Magnani's message of "Fri, 29 Jun 2012 12:19:10 -0500") Message-ID: <877guqt2kf.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1941 Lines: 64 "Steven J. Magnani" writes: > fat_encode_fh() can fetch an invalid i_pos value on systems > where 64-bit accesses are not atomic. Make it use the same > accessor as the rest of the FAT code. > > Signed-off-by: Steven J. Magnani > --- > diff -uprN linux-3.5-rc4/fs/fat/inode.c new/fs/fat/inode.c > --- linux-3.5-rc4/fs/fat/inode.c 2012-06-29 11:20:12.781348652 -0500 > +++ new/fs/fat/inode.c 2012-06-29 11:25:29.484713183 -0500 > @@ -738,22 +738,22 @@ static int > fat_encode_fh(struct inode *inode, __u32 *fh, int *lenp, struct inode *parent) > { > int len = *lenp; > - u32 ipos_h, ipos_m, ipos_l; > + struct super_block *sb = inode->i_sb; > + struct msdos_sb_info *sbi = MSDOS_SB(sb); sb seems to be unused. So, we can just struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); true? Otherwise, ack. Acked-by: OGAWA Hirofumi Just curious, this happened on the real system? I recently heard about NFS issue. Thanks. > + loff_t i_pos; > > if (len < 5) { > *lenp = 5; > return 255; /* no room */ > } > > - ipos_h = MSDOS_I(inode)->i_pos >> 8; > - ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24; > - ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28; > + i_pos = fat_i_pos_read(sbi, inode); > *lenp = 5; > fh[0] = inode->i_ino; > fh[1] = inode->i_generation; > - fh[2] = ipos_h; > - fh[3] = ipos_m | MSDOS_I(inode)->i_logstart; > - fh[4] = ipos_l; > + fh[2] = i_pos >> 8; > + fh[3] = ((i_pos & 0xf0) << 24) | MSDOS_I(inode)->i_logstart; > + fh[4] = (i_pos & 0x0f) << 28; > if (parent) > fh[4] |= MSDOS_I(parent)->i_logstart; > return 3; > -- OGAWA Hirofumi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/