From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH 0/8] remove i_alloc_sem Date: Wed, 22 Jun 2011 01:54:25 +0200 Message-ID: <20110621235425.GA24067@quack.suse.cz> References: <20110620201533.847236272@bombadil.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: viro@zeniv.linux.org.uk, tglx@linutronix.de, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, hirofumi@mail.parknet.co.jp, mfasheh@suse.com, jlbec@evilplan.org, tytso@mit.edu To: Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20110620201533.847236272@bombadil.infradead.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Mon 20-06-11 16:15:33, Christoph Hellwig wrote: > i_alloc_sem has always been a bit of an odd "lock". It's the only remaining > rw_semaphore that can be released by a different thread than the one that > locked it, and it's use case in the core direct I/O code is more like a > counter given that the writers already have external serialization. > > This series removes it in favour of a simpler counter scheme, thus getting > rid of the rw_semaphore non-owner APIs as requests by Thomas, while at the > same time shrinking the size of struct inode by 160 bytes on 64-bit systems. > > The only nasty bit is that two filesystems (fat and ext4) have started > abusing the lock for their own purposes. I've added a new rw_semaphore ext4 abuse should be gone when Ted merges my rewrite of ext4_page_mkwrite()... Ted, what happened to that patch. Should I resend it? Honza -- Jan Kara SUSE Labs, CR