From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753043AbYKEXHe (ORCPT ); Wed, 5 Nov 2008 18:07:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751919AbYKEXHZ (ORCPT ); Wed, 5 Nov 2008 18:07:25 -0500 Received: from mail.fieldses.org ([66.93.2.214]:33130 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751887AbYKEXHY (ORCPT ); Wed, 5 Nov 2008 18:07:24 -0500 Date: Wed, 5 Nov 2008 18:07:15 -0500 To: Doug Nazar Cc: "'David Woodhouse'" , "'Al Viro'" , linux-kernel@vger.kernel.org Subject: Re: 2.6.28-rc3 truncates nfsd results Message-ID: <20081105230715.GP1455@fieldses.org> References: <000301c93eaa$fae98460$f0bc8d20$@ca> <20081104223000.GG10974@fieldses.org> <004a01c93f37$f2a09090$d7e1b1b0$@ca> <20081105214655.GK1455@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081105214655.GK1455@fieldses.org> User-Agent: Mutt/1.5.18 (2008-05-17) From: "J. Bruce Fields" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Seems good to me; I cleaned up commit message, as below, and I'll submit in a few days. If you didn't mind me adding a signed-off-by for you, that'd also be good. I hope we've got it right this time! --b. commit 19e1e96e0b51f9ad4cb0329e6b32a742cf9db713 Author: Doug Nazar Date: Wed Nov 5 06:16:28 2008 -0500 Fix nfsd truncation of readdir results Commit 8d7c4203 "nfsd: fix failure to set eof in readdir in some situations" introduced a bug: on a directory in an exported ext3 filesystem with dir_index unset, a READDIR will only return about 250 entries, even if the directory was larger. Bisected it back to this commit; reverting it fixes the problem. It turns out that in this case ext3 reads a block at a time, then returns from readdir, which means we can end up with buf.full==0 but with more entries in the directory still to be read. Before 8d7c4203 (but after c002a6c797 "Optimise NFS readdir hack slightly"), this would cause us to return the READDIR result immediately, but with the eof bit unset. That could cause a performance regression (because the client would need more roundtrips to the server to read the whole directory), but no loss in correctness, since the cleared eof bit caused the client to send another readdir. After 8d7c4203, the setting of the eof bit made this a correctness problem. So, move nfserr_eof into the loop and remove the buf.full check so that we loop until buf.used==0. The following seems to do the right thing and reduces the network traffic since we don't return a READDIR result until the buffer is full. Tested on an empty directory & large directory; eof is properly sent and there are no more short buffers. Signed-off-by: J. Bruce Fields diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 848a03e..4433c8f 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1875,11 +1875,11 @@ static int nfsd_buffered_readdir(struct file *file, filldir_t func, return -ENOMEM; offset = *offsetp; - cdp->err = nfserr_eof; /* will be cleared on successful read */ while (1) { unsigned int reclen; + cdp->err = nfserr_eof; /* will be cleared on successful read */ buf.used = 0; buf.full = 0; @@ -1912,9 +1912,6 @@ static int nfsd_buffered_readdir(struct file *file, filldir_t func, de = (struct buffered_dirent *)((char *)de + reclen); } offset = vfs_llseek(file, 0, SEEK_CUR); - cdp->err = nfserr_eof; - if (!buf.full) - break; } done: