From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f200.google.com (mail-lj1-f200.google.com [209.85.208.200]) by kanga.kvack.org (Postfix) with ESMTP id 8584B6B74B8 for ; Wed, 5 Sep 2018 15:21:57 -0400 (EDT) Received: by mail-lj1-f200.google.com with SMTP id p8-v6so1756165ljg.10 for ; Wed, 05 Sep 2018 12:21:57 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id n74-v6sor1119551lfi.35.2018.09.05.12.21.55 for (Google Transport Security); Wed, 05 Sep 2018 12:21:56 -0700 (PDT) MIME-Version: 1.0 References: <0000000000004f6b5805751a8189@google.com> <20180905085545.GD24902@quack2.suse.cz> <20180905133459.GF23909@thunk.org> In-Reply-To: <20180905133459.GF23909@thunk.org> From: Souptick Joarder Date: Thu, 6 Sep 2018 00:54:50 +0530 Message-ID: Subject: Re: linux-next test error Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Theodore Ts'o , Jan Kara , syzbot+87a05ae4accd500f5242@syzkaller.appspotmail.com, ak@linux.intel.com, Andrew Morton , linux-kernel@vger.kernel.org, Linux-MM , mawilcox@microsoft.com, mgorman@techsingularity.net, syzkaller-bugs@googlegroups.com, tim.c.chen@linux.intel.com, zwisler@kernel.org, Matthew Wilcox On Wed, Sep 5, 2018 at 7:05 PM Theodore Y. Ts'o wrote: > > On Wed, Sep 05, 2018 at 03:20:16PM +0530, Souptick Joarder wrote: > > > > "fs: convert return type int to vm_fault_t" is still under > > review/discusson and not yet merge > > into linux-next. I am not seeing it into linux-next tree.Can you > > please share the commit id ? > > It's at: 83c0adddcc6ed128168e7b87eaed0c21eac908e4 in the Linux Next > branch. > > Dmitry, can you try reverting this commit and see if it makes the > problem go away? > > Souptick, can we just NACK this patch and completely drop it from all > trees? Ok, I will correct it and post v3. > > I think we need to be a *lot* more careful about this vm_fault_t patch > thing. If you can't be bothered to run xfstests, we need to introduce > a new function which replaces block_page_mkwrite() --- and then let > each file system try to convert over to it at their own pace, after > they've done regression testing. > > - Ted Chris has his opinion, block_page_mkwrite is only called by ext4 and nilfs2 anyway, so converting both callers over should not be a problem, as long as it actually is done properly. Matthew's opinion in other mail thread - > +vm_fault_t block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, > + get_block_t get_block, int *err) I don't like returning both the errno and the vm_fault_t. To me that's a sign we need to rethink this interface. I have two suggestions. First, we could allocate a new VM_FAULT_NOSPC bit. Second, we could repurpose one of the existing bits, such as VM_FAULT_RETRY for this purpose. > -int ext4_page_mkwrite(struct vm_fault *vmf) > +vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) I also think perhaps we could start by _not_ converting block_page_mkwrite(). Just convert ext4_page_mkwrite(), and save converting block_page_mkwrite() for later. Which approach Shall I take ??