linux-kernel - Re: [PATCH] [REGRESSION] ovl: Handle ENOSYS when fileattr support is missing in lower/upper fs

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Message-ID: <CALKgVmdyQwXcwQHBNEzE7XsCYmqQFeNLXZ5-hTPErjYz4PvgaQ@mail.gmail.com>
Date:   Tue, 14 Mar 2023 19:43:34 -0700
From:   Jonathan Katz <jkatz@...mlabs.org>
To:     Miklos Szeredi <miklos@...redi.hu>
Cc:     jonathan@...m.org,
        Christian Kohlschütter 
        <christian@...lschutter.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        overlayfs <linux-unionfs@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>
Subject: Re: [PATCH] [REGRESSION] ovl: Handle ENOSYS when fileattr support is
 missing in lower/upper fs

On Thu, Mar 9, 2023 at 7:31 AM Miklos Szeredi <miklos@...redi.hu> wrote:
>
> On Tue, 7 Mar 2023 at 18:14, Jonathan Katz <jkatz@...mlabs.org> wrote:
> >
> > On Tue, Mar 7, 2023 at 12:38 AM Miklos Szeredi <miklos@...redi.hu> wrote:
> > >
> > > On Tue, 7 Mar 2023 at 02:12, Jonathan Katz <jkatz@...mlabs.org> wrote:
> > > >
> > > > Hi all,
> > > >
> > > > In pursuing this issue, I downloaded the kernel source to see if I
> > > > could debug it further.  In so doing, it looks like Christian's patch
> > > > was never committed to the main source tree (sorry if my terminology
> > > > is wrong).  This is up to and including the 6.3-rc1.  I could also
> > > > find no mention of the fix in the log.
> > > >
> > > > I am trying to manually apply this patch now, but, I am wondering if
> > > > there was some reason that it was not applied (e.g. it introduces some
> > > > instability?)?
> > >
> > > It's fixing the bug in the wrong place, i.e. it's checking for an
> > > -ENOSYS return from vfs_fileattr_get(), but that return value is not
> > > valid at that point.
> > >
> > > The right way to fix this bug is to prevent -ENOSYS from being
> > > returned in the first place.
> > >
> > > Commit 02c0cab8e734 ("fuse: ioctl: translate ENOSYS") fixes one of
> > > those bugs, but of course it's possible that I missed something in
> > > that fix.
> > >
> > > Can you please first verify that an upstream kernel (>v6.0) can also
> > > reproduce this issue?
> >
> > Got ya.  that makes a lot of sense, thank you.
> >
> > I have confirmed that I continue to get the error with 6.2 .
> > quick summary of the lowerdir:
> >    server ---- NFS(ro) ---- > client "/nfs"
> >    client "/nfs" --- bindfs(uidmap) --- > client "/lower"
>
> Can you please run bindfs in debugging mode (-d) and send the
> resulting log after reproducing the issue?
>
> Thanks,
> Miklos

OUCH -- MY LAST EMAIL WAS REJECTED FOR BEING TOO BIG
I HOPE THAT I AM SUMMARIZING THE RELEVANT INFORMATION HERE:


Hi Miklos, thank you.... I am sorry for the delay.

The log is somewhat long and was sent in a separate email.

I broke up the log into entries to try to match the chronology of actions:
   * ENTRY 1 nfs mount the external drive
   * ENTRY 2 perform the bind fs
   * ENTRY 3 perform the overlay
   * ENTRY 4 restart smb
   * ENTRY 5 mount the filesystem on a windows box
   * ENTRY 6 performing some navigation on the windows file explorer
   * ENTRY 7 attempt to open a data file with the windows application.

The only place that generated a kernel error in dmesg was at ENTRY 7.

Because the logs are so big, I tried to parse them, I may have made a
mistake or omitted information -- if you think so, as mentioned, the
full bindfs logs were sent separately


Here is my attempt to parse out the errors associated with this dmesg entry:

[ 1925.705908] overlayfs: failed to retrieve lower fileattr (8020
MeOHH2O RecoverySample1-20221216-A-JJL-WebinarHilic10C-TOF-TT54-Neg-1632.d/chromatography-data.sqlite,
err=-38)

--
unique: 1550, opcode: GETXATTR (22), nodeid: 71, insize: 73, pid: 3458
getxattr /eimstims1/deleteme2/8020 MeOHH2O
RecoverySample1-20221216-A-JJL-WebinarHilic10C-TOF-TT54-Neg-1632.d/chromatography-data-pre.sqlite
trusted.overlay.metacopy 0
   unique: 1550, error: -95 (Operation not supported), outsize: 16
--
unique: 3922, opcode: GETXATTR (22), nodeid: 71, insize: 72, pid: 3458
getxattr /eimstims1/deleteme2/8020 MeOHH2O
RecoverySample1-20221216-A-JJL-WebinarHilic10C-TOF-TT54-Neg-1632.d/chromatography-data-pre.sqlite
system.posix_acl_access 132
   unique: 3922, error: -95 (Operation not supported), outsize: 16
--
unique: 3954, opcode: GETXATTR (22), nodeid: 71, insize: 72, pid: 3458
getxattr /eimstims1/deleteme2/8020 MeOHH2O
RecoverySample1-20221216-A-JJL-WebinarHilic10C-TOF-TT54-Neg-1632.d/chromatography-data-pre.sqlite
system.posix_acl_access 132
   unique: 3954, error: -95 (Operation not supported), outsize: 16
--
unique: 3960, opcode: GETXATTR (22), nodeid: 71, insize: 72, pid: 3458
getxattr /eimstims1/deleteme2/8020 MeOHH2O
RecoverySample1-20221216-A-JJL-WebinarHilic10C-TOF-TT54-Neg-1632.d/chromatography-data-pre.sqlite
system.posix_acl_access 132
   unique: 3960, error: -95 (Operation not supported), outsize: 16


Thank you again!

-Jonathan