Message-Id: <20210208125427.CFC7C75EED90@huitzilopochtli.metztli-it.com>
Date:   Mon,  8 Feb 2021 04:54:27 -0800 (PST)
From:   Metztli Information Technology <jose.r.r@...ztli.com>
To:     <edward.shishkin@...il.com>, <reiserfs-devel@...r.kernel.org>,
        <hch@....de>, <linux-kernel@...r.kernel.org>
Subject: Re: [reiser4 SFRN 5.1.3] kernel [5.10.x] read not supported for file /test-exec \(pid: 10094 comm: debootstrap\)

On Wed, Dec 23, 2020 at 3:40 PM Edward Shishkin <edward.shishkin@...il.com> wrote:
>
> On 12/23/2020 05:01 PM, Metztli Information Technology wrote:
> > Niltze [Ð—Ð´Ñ€Ð°Ð²Ñ Ñ‚Ð²ÑƒÐ¹Ñ‚Ðµ : Hello], Ed-
> >
> > I built Linux kernel 5.10.1-1 within the 'Debian way' -- as usual -- to generate a kernel component for my Debian-Installer (d-i).
> > The patch I applied is reiser4-for-5.10-rc3.patch.gz from v5-unstable.
> >
> > Once I built the proper reiser4progs-2.0.4.tar.gz and generated one set of components for d-i I built the d-i image.
> >
> > Fact is, the installer throws an error in *both* bare metal and VirtualBox 6.1.16:
> > ...
> > Dec 22 20:19:56 main-menu[330]: INFO: Menu item 'bootstrap-base' selected
> > Dec 22 20:19:56 debootstrap: /usr/sbin/debootstrap --components=main --debian-installer --resolve-deps --keyring=/usr/share/keyrings/archive.gpg buster /target http://deb.debian.org/debian/
> > Dec 22 20:19:56 debootstrap: /usr/sbin/debootstrap: line 1596: /target/test-exec: Invalid argument
> > Dec 22 20:19:56 kernel: [ 1018.632648] kernel read not supported for file /test-exec (pid: 10077 comm: debootstrap)
> > Dec 22 20:19:56 debootstrap: E: NOEXEC
> > Dec 22 20:19:56 debootstrap: EF: Cannot install into target '/target' mounted with noexec or nodev
> > Dec 22 20:20:12 base-installer: error: exiting on error base-installer/debootstrap-failed
> > Dec 22 20:20:14 main-menu[330]: WARNING **: Configuring 'bootstrap-base' failed with error code 1
> > Dec 22 20:20:14 main-menu[330]: WARNING **: Menu item 'bootstrap-base' failed.
> > Dec 22 20:20:15 main-menu[330]: INFO: Falling back to the package description for brltty-udeb
> >
>
> [...]
>
> >
> > Apparently, d-i [Debian-installer] complains about being unable to set the test file executable and causes the error when 1 is returned.
> > Notwithstanding, I manually verified that I am able to touch a file and set it +x executable.
> >
> > Furthermore, tricking the function return value to 0 I am able to make d-i continue with the latest SFRN5 installation (see [*trick*] below); yet, subsequently halts again with
> > an apparently related error --can not proceed any further.
> >
> > Digging deeper with dmesg, we can see that apparently it is the kernel which cannot 'read' properly. Please find a partial dmesg log with relevant output
> > from an attempt on my physical development machine.
> > ...
> > [  508.614488] Loading Reiser4 (Software Framework Release: 5.1.3). See reiser4.wiki.kernel.org for a description of Reiser4.
> > [  508.661951] SGI XFS with ACLs, security attributes, realtime, quota, no debug enabled
> > [  509.326270] device-mapper: uevent: version 1.0.3
> > [  509.326505] device-mapper: ioctl: 4.43.0-ioctl (2020-10-01) initialised: dm-devel@...hat.com
> > [  509.902828]  sda: sda1 sda2 sda3 sda4 sda5 sda6
> > [  509.915300]  sdb: sdb1 sdb2 sdb3
> > [  511.973360]  sdb: sdb1 sdb2 sdb3
> > [  627.525371] Adding 9765884k swap on /dev/sda3.  Priority:-2 extents:1 across:9765884k FS
> > [  636.240812] reiser4[mount(9430)]: reiser4_register_subvol (fs/reiser4/init_volume.c:222)[edward-1932]:
> > [  636.240812] NOTICE: brick /dev/sda6 has been registered
> > [  636.243003] reiser4 (sda6): found disk format 5.1.3.
> > [  643.759971] reiser4 (/dev/sda6): using Hybrid Transaction Model.
> > [  643.759980] reiser4: brick /dev/sda6 activated
> > [  643.788537] EXT4-fs (sda1): mounting ext2 file system using the ext4 subsystem
> > [  643.813474] EXT4-fs (sda1): mounted filesystem without journal. Opts: (null)
> > [  643.813488] ext2 filesystem being mounted at /target/boot supports timestamps until 2038 (0x7fffffff)
> > [  648.168730] kernel read not supported for file /test-exec (pid: 9876 comm: debootstrap) [*trick*]
> > [  898.761385] reiser4: brick /dev/sda6 deactivated
> > [  991.001332] reiser4 (sda6): found disk format 5.1.3.
> > [  999.093471] reiser4 (/dev/sda6): using Hybrid Transaction Model.
> > [  999.093480] reiser4: brick /dev/sda6 activated
> > [ 1009.340117] EXT4-fs (sda1): mounting ext2 file system using the ext4 subsystem
> > [ 1009.362722] EXT4-fs (sda1): mounted filesystem without journal. Opts: (null)
> > [ 1009.362737] ext2 filesystem being mounted at /target/boot supports timestamps until 2038 (0x7fffffff)
> > [ 6373.748413] kernel read not supported for file /test-exec (pid: 10094 comm: debootstrap)
> > [ 6413.169920] kernel read not supported for file /usr/bin/true (pid: 15960 comm: chroot)
>
>
> Hello.
>
> This is because of VFS changes in Linux-5.10.X.
> Specifically, because of the following patch:
> https://lkml.org/lkml/2020/8/17/174
> In the upstream git repository it is commit 4d03e3cc59828c82ee89ea6e2
>
> So, Christoph, what to do now for file systems which implement
> ->read() method of file operations?

*deafening silence* it appears that -- in the best of cases -- Christoph engaged in an act of _iter masturbation [1];
and in the worst of cases, the gentleman was aiming straight at reiser4.

>... It seems that chroot doesn't work
> for them. And people are not able to release distros with upgraded
> kernels..

Not only 'chroot doesn't work' for us, but even after replacing the kernel in a reiser4 (proper SFRN ;) instance and
 upon an initial Linux 5.10.x kernel boot:
...
kernel read not supported for file usr/lib/systemd/systemd (pid: 1 comm: run-init)
kernel panic -- not syncing: Attempted to kill init! exitcod=0x00000100
...

Fact is some of us have commercial interests when deploying reiser4, both in cloud instances, baremetal, and on-premises.

In the future if -- and only if -- our reiser4 efforts come to successful fruition, quite likely in due time we will be
 able to financially commit to the Penguin's Linux Foundation temple, just like large corporations do
 in exchange for indulgences[2] which virtue-wash their past and/or current corp. officers' *substantially darker deeds*;
 heck, 'indulgence trafficking' seems to assuage->numb->arg(STFU) that 'virtuous' cult of GNU/Linux
 developers/gatekeepers/maintainers' frivolous, *narcissist*, ethics and/or moralities so often piled up against
 Reiser's work --which, paradoxically(!?), actually was largely implemented by Russian developers ;)

In the meantime, I hacked a reverse patch that undoes some(all) of the surreptitious lethal attack on reiser4 fs
 -- at least on AMD64 architectures (I did away with other arch/Kconfigs).
And no, I am not a git pro-, undoing what I could of commit 4d03e3cc59828c82ee89ea6e27a2f3cdf95aaadf (as your hinted, Ed)
 does not fix the 'kernel read' issue.

Notwithstanding, I would appreciate if you can take a look at the attached patch. Probably it can be streamlined and/or improved
 further to minimize pain on subsequent Linux kernel upgrades.

The patch has been tested in my local development machine environment --
 as I intalled the generated reiser4 -enabled linux 5.10.13/14 meta/kernel into a Debian Bullseye already running reiser4 (with proper SFRN)
 and the kernel booted nicely. Subsequently, after installing the linux headers, etc. I built a couple of upgraded kernels
 in Debian Buster GCC-8 and Bullseye GCC-10 environments -- thus the hack seems to be stable.

Additionally, I have just made a Debian-Installer (d-i) with a 'kernel read' -patched Linux 5.10.14.1 which successfully installed
 into a VirtualBox 6.1.18 VM:
< https://metztli.it/buster/reiser4_0_2-linux-5.10.14-kernel-read-patched.png >

>
> Thanks,
> Edward.

Best Professional Regards.

[1] 
"The bug was fixed, again way back in 2010, and over time chip-designers have moved on to improved memory management techniques.
Torvalds wrote that this sort of memory space override has been banished from the x86, powerpc, s390 and RISC-V architectures."
< https://www.theregister.com/2020/10/25/linux_5_10_rc1/ >

[2] https://www.britannica.com/topic/indulgence

-- 
Jose R R
http://metztli.it
---------------------------------------------------------------------------------------------
Download Metztli Reiser4: Debian Buster w/ Linux 5.9.16 AMD64
---------------------------------------------------------------------------------------------
feats ZSTD compression https://sf.net/projects/metztli-reiser4/
---------------------------------------------------------------------------------------------
or SFRN 5.1.3, Metztli Reiser5 https://sf.net/projects/debian-reiser4/
-------------------------------------------------------------------------------------------
Official current Reiser4 resources: https://reiser4.wiki.kernel.org/

Download attachment "linux-5.10.14-enable-kernel-read-on-reiser4.patch" of type "application/octet-stream" (45102 bytes)

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