From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH 08/10] ext4: endless truncate due to nonlocked dio readers V2 Date: Wed, 26 Sep 2012 16:05:38 +0200 Message-ID: <20120926140538.GH10145@quack.suse.cz> References: <1348487060-19598-1-git-send-email-dmonakhov@openvz.org> <1348487060-19598-9-git-send-email-dmonakhov@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, tytso@mit.edu, jack@suse.cz, lczerner@redhat.com To: Dmitry Monakhov Return-path: Received: from cantor2.suse.de ([195.135.220.15]:41723 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756152Ab2IZOFk (ORCPT ); Wed, 26 Sep 2012 10:05:40 -0400 Content-Disposition: inline In-Reply-To: <1348487060-19598-9-git-send-email-dmonakhov@openvz.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon 24-09-12 15:44:18, Dmitry Monakhov wrote: > If we have enough aggressive DIO readers, truncate and other dio > waiters will wait forever inside inode_dio_wait(). It is reasonable > to disable nonlock DIO read optimization during truncate. Umm, actually this is a problem with any inode_dio_wait() call in ext4, isn't it? So I'd just create ext4_inode_dio_wait() doing ext4_inode_block_unlocked_dio(inode); inode_dio_wait(inode); ext4_inode_resume_unlocked_dio(inode); and use it instead of inode_dio_wait(). Honza > Signed-off-by: Dmitry Monakhov > --- > fs/ext4/inode.c | 8 ++++++-- > 1 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 32e9701..d3f86e7 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -4330,9 +4330,13 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr) > if (attr->ia_valid & ATTR_SIZE) { > if (attr->ia_size != inode->i_size) { > truncate_setsize(inode, attr->ia_size); > - /* Inode size will be reduced, wait for dio in flight */ > - if (orphan) > + /* Inode size will be reduced, wait for dio in flight. > + * Temproraly disable unlocked DIO to prevent livelock */ ^^ Temporarily > + if (orphan) { > + ext4_inode_block_unlocked_dio(inode); > inode_dio_wait(inode); > + ext4_inode_resume_unlocked_dio(inode); > + } > } > ext4_truncate(inode); > } > -- > 1.7.7.6 > -- Jan Kara SUSE Labs, CR