Re: [PATCH] libxfs: report device open errors during topology probing

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Sep 02, 2026 at 07:59:54AM +0200, Christoph Hellwig wrote:
> On Tue, Sep 01, 2026 at 10:46:27AM +0200, Hans Holmberg wrote:
> > > I wonder if there are any valid failures from blkid_new_probe_from_filename
> > > where we'd want to continue?  Probably not as it doesn't really have an
> > > obvious failure path, but so far we continue here.  So the print is useful
> > > for sure, but I wonder if failing here might cause regressions in some
> > > really odd use case (containers without sysfs?  Although we'd run into
> > > trouble with that quickly in other places).
> > 
> > 
> > Yeah, it might be safer to just print the warning, and that would solve
> > my problem (no instructive error message),
> > 
> > On the other hand it's nice to fail early - but not if it causes regressions
> > of course.
> 
> Yeah, failing early is nice, but I'm a bit fearful we might break
> existing (but really weird setups).

AFAICT hidden sysfs doesn't seem to break libbkid's probing of devices:

# mount moo /sys/ -t tmpfs ; mkfs.xfs -f /dev/sda
meta-data=/dev/sda               isize=512    agcount=4, agsize=644992 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=1
         =                       reflink=1    bigtime=1 inobtcount=1 nrext64=1
         =                       exchange=1   metadir=1
data     =                       bsize=4096   blocks=2579968, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1, parent=1
log      =internal log           bsize=4096   blocks=16384, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
         =                       rgcount=0    rgsize=268435456 extents
         =                       zoned=0      start=0 reserved=0
Discarding blocks...Done.

--D