On 3/6/18 2:07 PM, Randy Dunlap wrote: > On 03/05/2018 10:47 PM, Dave Chinner wrote: >> On Mon, Mar 05, 2018 at 09:12:03PM -0800, Randy Dunlap wrote: >>> On 03/05/2018 08:45 PM, Eric Sandeen wrote: >>>> On 3/5/18 10:42 PM, Randy Dunlap wrote: >>>>>>> It's a new OS/installer. OpenSUSE Tumbleweed, which is their bleeding edge >>>>>>> rolling updates release. >>>>>> Hrmph. A lot of things go into this behavior, it may not be a kernel change at >>>>>> all that has made it show up now... >>>>> Yes, it could be that wonderful systemd or something else. >>>> >>>> I think I'd pursue a parallel track of bugging SUSE about the issue... ;) >>>> >>>> (I don't think the kernel will ever just downgrade an rw mount request to >>>> ro, or skip an ro->rw transition silently... leaving it ro does seem >>>> like an init bug, but *shrug* init long ago transitioned into deep magic.) >>> >>> More info: :( >>> >>> This problem happens when booting my own custom 4.16-rc3 kernel. >>> If I boot the OpenSUSE-supplied (4.15.7) kernel, the / fs is remounted rw later on. >>> >>> So I'm more or less back to "what am I doing wrong"? >> >> The filesystem probing order has probably changed. mount tries to >> use blkid to determine the filesytem type to use, and if that >> doesn't find a known type it will fall back to trying mounts with >> explicit types as per the filesystem type order listed in >> /proc/filesystems. (it's in the man mount page) Maybe the device >> module hasn't been loaded when blkid runs to probe existing block >> devices? >> >> These sorts of whacky behaviours have occurred for me in the past >> when either userspace behaviour changed, the order of filesystems >> listed in /proc/filesystems or module load order changed. Typically >> it's a difference in kernel config that causes such shenanigans. > > There is also a (big) difference in the $DISTRO using initramfs and my > custom kernel not using one. But in both cases the SATA/AHCI driver is > loaded/ready before ext4fs, so it's still a mystery to me. > > Eric, I tested your patch but it didn't help in my environment. Odd. It's supposed to be silent if ext3 doesn't recognize the features, but ext4 does. Too many moving parts. :/ -Eric
