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* nfs as lower
@ 2021-10-26  6:12 Carl Karsten
  2021-10-26  9:34 ` Amir Goldstein
  0 siblings, 1 reply; 2+ messages in thread
From: Carl Karsten @ 2021-10-26  6:12 UTC (permalink / raw)
  To: overlayfs

I am trying to replicate the setup described below,
(from: https://www.spinics.net/lists/linux-unionfs/msg07098.html )
which implies a successful mount, but all of my attempts error with:

mount: /e/merged: wrong fs type, bad option, bad superblock on
overlay, missing codepage or helper program, or other error.
[ 3640.328337] overlayfs: upper fs does not support tmpfile.
[ 3640.333245] overlayfs: upper fs does not support RENAME_WHITEOUT.
[ 3640.333266] overlayfs: upper fs does not support xattr, falling
back to index=off and metacopy=off.
[ 3640.333281] overlayfs: upper fs missing required features.

script and output:

#!/bin/bash -x
for x in a b c d e
do
    umount /$x/merged
    umount /$x/lower
    rm -rf /$x
    mkdir /$x /$x/lower /$x/upper /$x/work /$x/merged
done

mount -t nfs -o vers=3,ro,noatime
10.21.0.1:/srv/nfs/rpi/buster/root/merged /a/lower
mount -t overlay -o
lowerdir=/a/lower,upperdir=/a/upper,workdir=/a/work,default_permissions
overlay /a/merged

mount -t nfs -o ro,noatime 10.21.0.1:/srv/nfs/rpi/buster/root/merged /b/lower
mount -t overlay -o
lowerdir=/b/lower,upperdir=/b/upper,workdir=/b/work,default_permissions
overlay /b/merged

mount -t nfs -o vers=4.1,ro,noatime
10.21.0.1:/srv/nfs/rpi/buster/root/merged /c/lower
mount -t overlay -o
lowerdir=/c/lower,upperdir=/c/upper,workdir=/c/work,default_permissions
overlay /c/merged

mount -t nfs -o vers=3,ro,noatime,noacl
10.21.0.1:/srv/nfs/rpi/buster/root/merged /d/lower
mount -t overlay -o
lowerdir=/d/lower,upperdir=/d/upper,workdir=/d/work,default_permissions
overlay /d/merged

mount -t nfs -o ro,noatime,noacl
10.21.0.1:/srv/nfs/rpi/buster/root/merged /e/lower
mount -t overlay -o
vers=4.1,noacl,noatime,lowerdir=/e/lower,upperdir=/e/upper,workdir=/e/work,default_permissions
overlay /e/merged


+ for x in a b c d e
+ umount /a/merged
umount.nfs: remote share not in 'host:dir' format
umount.nfs: /a/merged: not mounted
+ umount /a/lower
+ rm -rf /a
+ mkdir /a /a/lower /a/upper /a/work /a/merged

(repeat 5 times)

+ mount -t nfs -o vers=3,ro,noatime
10.21.0.1:/srv/nfs/rpi/buster/root/merged /a/lower
+ mount -t overlay -o
lowerdir=/a/lower,upperdir=/a/upper,workdir=/a/work,default_permissions
overlay /a/merged
mount: /a/merged: wrong fs type, bad option, bad superblock on
overlay, missing codepage or helper program, or other error.

+ mount -t nfs -o ro,noatime 10.21.0.1:/srv/nfs/rpi/buster/root/merged /b/lower
+ mount -t overlay -o
lowerdir=/b/lower,upperdir=/b/upper,workdir=/b/work,default_permissions
overlay /b/merged
mount: /b/merged: wrong fs type, bad option, bad superblock on
overlay, missing codepage or helper program, or other error.

+ mount -t nfs -o vers=4.1,ro,noatime
10.21.0.1:/srv/nfs/rpi/buster/root/merged /c/lower
+ mount -t overlay -o
lowerdir=/c/lower,upperdir=/c/upper,workdir=/c/work,default_permissions
overlay /c/merged
mount: /c/merged: wrong fs type, bad option, bad superblock on
overlay, missing codepage or helper program, or other error.

+ mount -t nfs -o vers=3,ro,noatime,noacl
10.21.0.1:/srv/nfs/rpi/buster/root/merged /d/lower
+ mount -t overlay -o
lowerdir=/d/lower,upperdir=/d/upper,workdir=/d/work,default_permissions
overlay /d/merged
mount: /d/merged: wrong fs type, bad option, bad superblock on
overlay, missing codepage or helper program, or other error.

+ mount -t nfs -o ro,noatime,noacl
10.21.0.1:/srv/nfs/rpi/buster/root/merged /e/lower
+ mount -t overlay -o
vers=4.1,noacl,noatime,lowerdir=/e/lower,upperdir=/e/upper,workdir=/e/work,default_permissions
overlay /e/merged
mount: /e/merged: wrong fs type, bad option, bad superblock on
overlay, missing codepage or helper program, or other error.





> Hi,
>
> I'm using overlayfs with NFS v3 as a lower (mounted read-only) and a
> tmpfs as an upper filesystem. This works nicely since several years.
> So I get a writeable directory tree on an nfs client even the nfs was
> mounted ro.
>
> But then I mount the lower filesystem as NFS v4 (4.2) it does not
> work. Is this combination supposed to work?
> I tested this with kernels up to 5.2 yet but still no success.
>
>
> Here's my current test setup:
>
> NFS server kernel 5.2.0-0.bpo.2-amd64 (Debian 10 with newer kernel)
> NFS client kernel 5.2.0-0.bpo.2-amd64 (Debian 10 with newer kernel)
>
> On the NFS server I did once
> # mkdir /files/scratch/t/etc; echo test-buster > /files/scratch/t/etc/test1
>
> /etc/exports: /files/scratch  11.22.33.128/25(async,ro,no_subtree_check,no_root_squash)
>
> I can do more tests if you tell me what I can change.
> Here are the two tests result, one using nfs v3 the other using NFS v4.
>
> P.S.: After more research I think this may be a problem of a
>       filesystem missing xattr support. Do you have any experiences
>       using overlayfs using NFS v4 as lower fs?
>
> Any hints would be appreciated.
>
> regards Thomas
>
>
>
>
>
>
> NFS v3 mount
> ============
> Result: read and write works
>
>
> + mkdir -p /b/lower /a/upper /a/work /b/merged
> + mount -t nfs -overs=3,ro,noatime buster:/files/scratch/t /b/lower
> mount -t overlay -olowerdir=$lower,upperdir=$upper,workdir=$work,default_permissions overlay $merged || exit 88
> + cat /b/merged/etc/test1
> test-buster
> + sleep 3
> echo "write to merged" > $merged/etc/test1
> + echo 'write to merged'
> + sleep 3
> echo "write new file" > $merged/etc/test3
> + echo 'write new file'
>
> both files test1 and test3 exists with corect content.
>
> Here's the journalctl output of the overlayfs debug messages:
> Sep 16 13:45:04 suenner kernel: overlay: mkdir(work/work, 040000) = 0
> Sep 16 13:45:04 suenner kernel: overlay: tmpfile(work/work, 0100000) = 0
> Sep 16 13:45:04 suenner kernel: overlay: setxattr(work/work, "trusted.overlay.opaque", "0", 1, 0x0) = 0
> Sep 16 13:45:04 suenner kernel: overlay: open(00000000b7f8278e[etc/test1/l], 0100000) -> (00000000df256fc7, 0401100000)
> Sep 16 13:45:07 suenner kernel: overlay: setxattr(a/upper, "trusted.overlay.impure", "y", 1, 0x0) = 0
> Sep 16 13:45:07 suenner kernel: overlay: mkdir(work/#7, 040000) = 0
> Sep 16 13:45:07 suenner kernel: [168B blob data]
> Sep 16 13:45:07 suenner kernel: overlay: rename(work/#7, upper/etc, 0x0)
> Sep 16 13:45:07 suenner kernel: overlay: setxattr(upper/etc, "trusted.overlay.impure", "y", 1, 0x0) = 0
> Sep 16 13:45:07 suenner kernel: overlay: tmpfile(work/work, 0100644) = 0
> Sep 16 13:45:07 suenner kernel: [174B blob data]
> Sep 16 13:45:07 suenner kernel: overlay: link(work/#150994, etc/test1) = 0
> Sep 16 13:45:07 suenner kernel: overlay: open(000000001998a069[etc/test1/u], 0100001) -> (0000000009d1ebd4, 0401100001)
> Sep 16 13:45:10 suenner kernel: overlay: create(etc/test3, 0100666) = 0
> Sep 16 13:45:10 suenner kernel: overlay: open(0000000009d1ebd4[etc/test3/u], 0100001) -> (000000001998a069, 0401100001)
>
>
> The mount info
> buster:/files/scratch/t on /b/lower type nfs (ro,noatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=11.22.33.211,mountvers=3,mountport=45356,mountproto=udp,local_lock=none,addr=11.22.33.211)
> overlay on /b/merged type overlay (rw,relatime,lowerdir=/b/lower,upperdir=/a/upper,workdir=/a/work,default_permissions)
>
>
> -----------------------------------------------------------------------------------------------
> NFS v4 mount
> ============
> Result: read works, write does not work
>
> + mkdir -p /b/lower /a/upper /a/work /b/merged
> + mount -t nfs -oro,noatime buster:/files/scratch/t /b/lower
> + mount -t overlay -olowerdir=/b/lower,upperdir=/a/upper,workdir=/a/work,default_permissions overlay /b/merged
>
> + cat /b/merged/etc/test1
> test-buster
> + sleep 3
> echo "write to merged" > $merged/etc/test1
> + echo 'write to merged'
> /home/lange/fairesearch/xfai/overlay-test: line 32: /b/merged/etc/test1: Operation not supported
> + sleep 3
> echo "write new file" > $merged/etc/test3
> + echo 'write new file'
> /home/lange/fairesearch/xfai/overlay-test: line 34: /b/merged/etc/test3: Operation not supported
>
>
> Here's the journalctl output of the overlayfs debug messages:
> Sep 16 13:40:57 suenner kernel: overlay: mkdir(work/work, 040000) = 0
> Sep 16 13:40:57 suenner kernel: overlay: tmpfile(work/work, 0100000) = 0
> Sep 16 13:40:57 suenner kernel: overlay: setxattr(work/work, "trusted.overlay.opaque", "0", 1, 0x0) = 0
> Sep 16 13:40:57 suenner kernel: overlay: open(00000000ca5c0310[etc/test1/l], 0100000) -> (0000000023701f29, 0401100000)
> Sep 16 13:41:00 suenner kernel: overlay: setxattr(a/upper, "trusted.overlay.impure", "y", 1, 0x0) = 0
> Sep 16 13:41:00 suenner kernel: overlay: mkdir(work/#3, 040000) = 0
> Sep 16 13:41:00 suenner kernel: overlay: rmdir(work/#3) = 0
> Sep 16 13:41:03 suenner kernel: overlay: mkdir(work/#4, 040000) = 0
> Sep 16 13:41:03 suenner kernel: overlay: rmdir(work/#4) = 0
>
> The mount info:
> buster:/files/scratch/t on /b/lower type nfs4 (ro,noatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=11.22.33.136,local_lock=none,addr=11.22.33.211)
> overlay on /b/merged type overlay (rw,relatime,lowerdir=/b/lower,upperdir=/a/upper,workdir=/a/work,default_permissions)
>
> A manual test writing to the files using strace shows:
> openat(AT_FDCWD, "/b/merged/etc/test1", O_WRONLY|O_CREAT|O_TRUNC, 0666) = -1 EOPNOTSUPP (Operation not supported)
> openat(AT_FDCWD, "/


-- 
Carl K

^ permalink raw reply	[flat|nested] 2+ messages in thread
* Re: nfs as lower
  2021-10-26  6:12 nfs as lower Carl Karsten
@ 2021-10-26  9:34 ` Amir Goldstein
  0 siblings, 0 replies; 2+ messages in thread
From: Amir Goldstein @ 2021-10-26  9:34 UTC (permalink / raw)
  To: Carl Karsten; +Cc: overlayfs

On Tue, Oct 26, 2021 at 10:17 AM Carl Karsten <carl@nextdayvideo.com> wrote:
>
> I am trying to replicate the setup described below,
> (from: https://www.spinics.net/lists/linux-unionfs/msg07098.html )
> which implies a successful mount, but all of my attempts error with:
>
> mount: /e/merged: wrong fs type, bad option, bad superblock on
> overlay, missing codepage or helper program, or other error.
> [ 3640.328337] overlayfs: upper fs does not support tmpfile.
> [ 3640.333245] overlayfs: upper fs does not support RENAME_WHITEOUT.
> [ 3640.333266] overlayfs: upper fs does not support xattr, falling
> back to index=off and metacopy=off.
> [ 3640.333281] overlayfs: upper fs missing required features.
>

These kernel logs are the only relevant information.
Do you get the same kernel logs for all the overlayfs mount attempts?

As overlayfs is trying to say, the problem is clearly with upper fs
and there is no information about what upper fs is.

The setup that you are trying to replicate was using tmpfs as upper,
which should work fine.

Thanks,
Amir.

^ permalink raw reply	[flat|nested] 2+ messages in thread
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