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

[David Sterba <dsterba@suse.cz>]

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.