From: Theodore Ts'o Subject: Re: [PATCH 1/2] Make orphan functions no-op in no-journal mode Date: Mon, 17 Sep 2012 23:32:04 -0400 Message-ID: <20120918033204.GA32195@thunk.org> References: <1347904037-24229-1-git-send-email-anatol.pomozov@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, dmonakhov@openvz.org To: Anatol Pomozov Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:51213 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932657Ab2IRDcI (ORCPT ); Mon, 17 Sep 2012 23:32:08 -0400 Content-Disposition: inline In-Reply-To: <1347904037-24229-1-git-send-email-anatol.pomozov@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Sep 17, 2012 at 10:47:16AM -0700, Anatol Pomozov wrote: > This avoids using shared mutext and thus improves scalability of > no-journal mode. The goal of this change is similar to 3d287de3b828 > but it avoids mutex usage for all ext4_orphan_del(NULL,..) calls. It doesn't really improve scalability in no-journal except in the error case. This is because.... > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c > index 2a42cc0..6863cdf 100644 > --- a/fs/ext4/namei.c > +++ b/fs/ext4/namei.c > @@ -2362,6 +2362,8 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode) > struct ext4_iloc iloc; > int err = 0, rc; > > + if (!EXT4_SB(sb)->s_journal) > + return 0; > if (!ext4_handle_valid(handle)) > return 0; The two checks above are equivalent. If (!EXT4_SB(sb)->s_journal), then ext4_journal_start() will return return an "invalid" handle. So this change is purely cosmetic. I don't object to making the change for consistency with the change to be made in ext4_orphan_del() below, but we should remove the !ext4_handle_valid(handle) call in that case. > @@ -2436,6 +2438,8 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode) > struct ext4_iloc iloc; > int err = 0; > > + if (!EXT4_SB(inode->i_sb)->s_journal) > + return 0; > /* ext4_handle_valid() assumes a valid handle_t pointer */ > if (handle && !ext4_handle_valid(handle)) > return 0; We can remove the (handle && !ext4_handle_valid(handle)) conditional here too. - Ted