From: Jan Kara Subject: Re: [PATCH 08/11] ext4: endless truncate due to nonlocked dio readers V2 Date: Mon, 1 Oct 2012 18:41:17 +0200 Message-ID: <20121001164117.GD32092@quack.suse.cz> References: <1348847051-6746-1-git-send-email-dmonakhov@openvz.org> <1348847051-6746-9-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]:43964 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752827Ab2JAQlS (ORCPT ); Mon, 1 Oct 2012 12:41:18 -0400 Content-Disposition: inline In-Reply-To: <1348847051-6746-9-git-send-email-dmonakhov@openvz.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri 28-09-12 19:44:08, 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. OK, as per our previous discussion I agree. So you can add: Reviewed-by: Jan Kara Honza > > Signed-off-by: Dmitry Monakhov > --- > fs/ext4/inode.c | 9 +++++++-- > 1 files changed, 7 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 583cb3f..c40a98d 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -4305,9 +4305,14 @@ 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. > + * Temporarily disable dioread_nolock to prevent > + * livelock. */ > + 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 >