From: Ross Zwisler Subject: Re: [fstests PATCH] generic: add test for executables on read-only DAX mounts Date: Wed, 30 Aug 2017 22:02:55 -0600 Message-ID: <20170831040255.GB17095@linux.intel.com> References: <20170829213721.GA27686@linux.intel.com> <20170829223715.26507-1-ross.zwisler@linux.intel.com> <20170830145103.GA10163@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Theodore Ts'o , Eryu Guan , linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, Randy Dodgen , fstests-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20170830145103.GA10163-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" List-Id: linux-ext4.vger.kernel.org On Wed, Aug 30, 2017 at 07:51:03AM -0700, Christoph Hellwig wrote: > > The above patch fixes an issue with ext4 where executables cannot be run on > > read-only filesystems mounted with the DAX option. > > > > This issue does not appear to be present in ext2 or XFS, as they both pass > > the test. I've also confirmed outside of the test that they are both > > indeed able to execute binaries on read-only DAX mounts. > > It works for me on XFS. But I don't really understand why, as the fault > handler doesn't look very different. > > Maybe the problem is that in ext4_journal_start_sb will fail on > a read-only fs? > > Even for xfs/ext2 it would seem odd that things like sb_start_pagefault > just work. > > > +LS=$(which ls --skip-alias --skip-functions) 2>/dev/null > > +if [ $? -ne 0 ]; then > > + status=$? > > + echo "Couldn't find 'ls'!?" > > + exit > > +fi > > These checks all fail for me.. Huh...really? I'll send out v2 in a second, but if that fails for you as well can you try and give me a hint as to what's going wrong with the test in your setup?