Re: [PATCH v2 0/2] btrfs-progs: fix stale active zone after mkfs

[David Sterba <dsterba@suse.cz>]

On Mon, Sep 14, 2026 at 09:55:30PM +0200, David Sterba wrote:
> On Mon, Sep 14, 2026 at 07:40:12PM +0200, David Sterba wrote:
> > On Fri, Sep 04, 2026 at 08:24:42AM +0200, Johannes Thumshirn wrote:
> > > On zoned devices, mkfs can leave a stale zone behind that is used as a
> > > staging area but never reset. This zone is not backed by a chunk or
> > > device extent, so the FS itself does not account it as used. On devices
> > > that have a limitied active zone budget this can lead to premature
> > > ENOSPC and/or an exhaustion of active zones.
> > > 
> > > Fix it in mkfs for new file-systems and also add a check to fsck to find
> > > such zones and repair them with '--repair'.
> > > 
> > > Changes to v1:
> > > - fix a bug in fsck where it had a stale return value propagated.
> > > 
> > > Johannes Thumshirn (2):
> > >   btrfs-progs: zoned: refresh stale cached zone state in
> > >     btrfs_reset_dev_zone()
> > >   btrfs-progs: check: detect leaked active zones on zoned devices
> > 
> > The build fails on older distros (Centos 8, Leap 15.3/16.0):
> > 
> >   CC       check/main.o
> > check/main.c: In function 'check_zoned_active_zones':
> > check/main.c:9220:12: error: 'struct blk_zone' has no member named 'type'
> >     if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
> >             ^~
> > check/main.c:9220:22: error: 'BLK_ZONE_TYPE_CONVENTIONAL' undeclared (first use in this function)
> >     if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
> >                       ^~~~~~~~~~~~~~~~~~~~~~~~~~
> > check/main.c:9220:22: note: each undeclared identifier is reported only once for each function it appears in
> > check/main.c:9222:12: error: 'struct blk_zone' has no member named 'cond'
> >     if (zone->cond == BLK_ZONE_COND_EMPTY)
> >             ^~
> > check/main.c:9222:22: error: 'BLK_ZONE_COND_EMPTY' undeclared (first use in this function)
> >     if (zone->cond == BLK_ZONE_COND_EMPTY)
> >                       ^~~~~~~~~~~~~~~~~~~
> > 
> > The types were added in f5f2bad67a45 ("block: make the new blkzoned UAPI
> > constants discoverable") in 2016 and with the rest of the zoned userspace code
> > so it's not something recent.
> > 
> > I haven't looked what's the problem, this should be reproducible locally using
> > the "ci/ci-centos8" scripts (needs docker).
> 
> It fails with --disable-zoned, regardless if the zoned headers are
> present or complete. Centos 8 build fine with --enable-zoned, I don't
> know when it started to work. On Leap 15.3 the header is only partial,
> lacks zone capacity, so it must be disabled.
> 
> As a fix an #ifdef around check_zoned_active_zones() should work.

Fixed in devel.