From owner-svn-src-all@FreeBSD.ORG Tue Nov 20 12:20:59 2012 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 75D96E63; Tue, 20 Nov 2012 12:20:59 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-lb0-f182.google.com (mail-lb0-f182.google.com [209.85.217.182]) by mx1.freebsd.org (Postfix) with ESMTP id 8AF308FC0C; Tue, 20 Nov 2012 12:20:58 +0000 (UTC) Received: by mail-lb0-f182.google.com with SMTP id go10so2988191lbb.13 for ; Tue, 20 Nov 2012 04:20:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=B4JWPujATvhyKjWeHu1NaML+MxMRx3E6fpXm/twfJFM=; b=1DuXZOIcfIlQ38OXf4PvCQnOokttgKUXXU/pZXtP3tROVna6urjFl0hGdo3GJnEZ6o PboUde5vR2OEr8uDleKU2Exk2KYDtMNBUvc/4d3I11wiTq/mCjsL1WRr8TvkYxWW1IVk jxzygWhSNV5Sbq69XJn3ZMMl2Odm8HOL4hbvBCQ39LbQIRDAA5AxH3FESj+dQQrBvuMs zFS4K1KZvzQkUQN04Ez+9luzIYDeGsvdQZPNSHPNe5t9arc3IpvnuHa+1eZcZPK/ZQ3e +5nUjW/3qc1s6yMmZkgiygA95LwhPZVf0I7iLx6ZWjwEHLvoBT+6CCmKMS9svhv8exaq 1pXA== MIME-Version: 1.0 Received: by 10.112.26.67 with SMTP id j3mr6492309lbg.39.1353414057258; Tue, 20 Nov 2012 04:20:57 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.112.134.5 with HTTP; Tue, 20 Nov 2012 04:20:57 -0800 (PST) In-Reply-To: <20121120230708.G6016@besplex.bde.org> References: <201211192243.qAJMhjFF055708@svn.freebsd.org> <20121120162708.I924@besplex.bde.org> <20121120230708.G6016@besplex.bde.org> Date: Tue, 20 Nov 2012 12:20:57 +0000 X-Google-Sender-Auth: PrMnFm2vxcVVncWooPgo9wxy3cs Message-ID: Subject: Re: svn commit: r243311 - in head/sys: fs/ext2fs fs/msdosfs fs/nfsclient fs/nullfs fs/unionfs gnu/fs/reiserfs nfsclient ufs/ffs From: Attilio Rao To: Bruce Evans Content-Type: text/plain; charset=UTF-8 Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Nov 2012 12:20:59 -0000 On 11/20/12, Bruce Evans wrote: > On Tue, 20 Nov 2012, Attilio Rao wrote: > >> On Tue, Nov 20, 2012 at 6:20 AM, Bruce Evans >> wrote: >>> On Mon, 19 Nov 2012, Attilio Rao wrote: >>> >>>> Log: >>>> r16312 is not any longer real since many years (likely since when VFS >>>> received granular locking) but the comment present in UFS has been >>>> copied all over other filesystems code incorrectly for several times. >>>> >>>> Removes comments that makes no sense now. >>> >>> >>> It still made sense (except for bitrot in the function name), but might >>> not >>> be true). The code made sense with it. Now the code makes no sense. >>> >>> >>>> Modified: head/sys/ufs/ffs/ffs_vfsops.c >>>> >>>> ============================================================================== >>>> --- head/sys/ufs/ffs/ffs_vfsops.c Mon Nov 19 21:58:14 2012 >>>> (r243310) >>>> +++ head/sys/ufs/ffs/ffs_vfsops.c Mon Nov 19 22:43:45 2012 >>>> (r243311) >>>> @@ -1676,14 +1676,6 @@ ffs_vgetf(mp, ino, flags, vpp, ffs_flags >>>> ump = VFSTOUFS(mp); >>>> dev = ump->um_dev; >>>> fs = ump->um_fs; >>>> - >>>> - /* >>>> - * If this malloc() is performed after the getnewvnode() >>> >>> >>> This malloc() didn't match the code, which uses uma_zalloc(). Old >>> versions used MALLOC() in both the comment and the code. ffs's comment >>> was updated to say malloc() when the code was changed to use malloc(), >>> then rotted when the code was changed to use uma_zalloc(). In some >>> other file systems, the comment still said MALLOC(). >>> >>> >>>> - * it might block, leaving a vnode with a NULL v_data to be >>>> - * found by ffs_sync() if a sync happens to fire right then, >>>> - * which will cause a panic because ffs_sync() blindly >>>> - * dereferences vp->v_data (as well it should). >>>> - */ >>>> ip = uma_zalloc(uma_inode, M_WAITOK | M_ZERO); >>>> >>>> /* Allocate a new vnode/inode. */ >>>> >>> >>> The code makes no sense now. The comment explains why ip is allocated >>> before vp, instead of in the natural, opposite order like it used to >>> be. Allocating things in an unnatural order requires extra code to >>> free ip when the allocation of vp fails. >> >> "Used to be" is very arguably. The code has been like its current form >> many more years than the opposite (16 against 3 I think). >> And the code makes perfectly sense if you know the history. So I don't >> agree with you. > > But it shouldn't be necessary to know the history of the code to > understand it. The code only makes sense if its comment is not removed, > or if you know the history of the code so that you can restore the > removed comment. However, if the comment makes no sense as you claim, > then the code that it it describes makes no sense. The "code that makes no sense" is basically the justification to have the allocation before the getnewvnode(). It makes no sense because the order makes no sense (you can allocate before or after getnewvnode(), you won't have v_data corruption as the comment claims). Hence the code makes no sense. I don't understand what is the point you are trying to make honestly. Attilio -- Peace can only be achieved by understanding - A. Einstein