Re: [PATCH 0/5] xfsdump, xfsprogs distro builds and DEBUG=

[Donald Douwsma <ddouwsma@redhat.com>]

On 14/3/26 00:12, Andrey Albershteyn wrote:
> On 2026-02-24 18:17:07, Donald Douwsma wrote:
>> tldr; Fedora builds with -DDEBUG, is that what folk want or expect?
>>
>> We see cases from the field where xfsrestore aborts on an assert(3).
>> In each case there's a real problem that needs to be fixed, but these
>> problems are preventing folk from restoring their data. With the asserts
>> suppressed or removed xfsrestore usually does something sane enough, at
>> worst leaving restored content in the orphanage where a user can find
>> it.
>>
>> This was notably seen with the original xfsdump bind mount fix, now
>> we're seeing asserts fire during cumulative restores in
>> noref_elim_recurse.
>>
>>   xfsrestore: tree.c:1421: noref_elim_recurse: Assertion 'isrealpr' failed
>>
>> This appears to be caused by a rename to within the tree between restore
>> levels, or a combination of modifications during occurring during the
>> dump. Fixing it will likely require changes in noref_elim_recurse, or
>> tree_post, to ensure elements of the tree are created for these edge
>> cases.
>>
>> But why are we seeing assert(3) active in Fedora based distro builds?
>>
>> xfsprogs and xfsdump m4/package_globals.m4 shows builds should default
>> to DEBUG and xfsdump doc/INSTALL talks about how to turn off asserts and
>> create an optimized build, but only Debian has its build rules in-tree,
>> where they set DEBUG=-DNDEBUG.
>>
>> Building locally on Fedora or similar gets varied results with recent
>> Fedora versions building as if DEBUG=-DNDEBUG was set within the realm
>> of configure or autoconf, which may be misleading people.
>>
>> But for Fedora release builds we can see that they're building with
>> DEBUG=-DDEBUG resulting in gcc called with -DDEBUG in the build logs.
>>
>>   https://src.fedoraproject.org/rpms/xfsdump
>>   https://kojipkgs.fedoraproject.org//packages/xfsdump/3.2.0/4.fc44/data/logs/x86_64/build.log
>>
>>   https://src.fedoraproject.org/rpms/xfsprogs
>>   https://kojipkgs.fedoraproject.org//packages/xfsprogs/6.18.0/2.fc44/data/logs/x86_64/build.log
>>
>> I don't think the intention was to have these build as DEBUG, but that
>> seems to be the current result. But before I dig into this further can I
>> confirm what people think this should do?
>>
>> The following series is illustrative of the changes to build xfsdump
>> cleanly with DEBUG=-DNDEBUG, or the type of downstream workarounds
>> required to help end users hitting problems for the status quo.
>>
>> Don
>>
>> Donald Douwsma (5):
>>   xfsrestore: remove unused variable strctxp
>>   annotate variables only used for assert
>>   xfsrestore: include TREE_DEBUG all builds
> 
> First 3 patches looks good to me to include, not sure about the
> rest and the original use of the those asserts.
> 

Thanks for looking over these.

I've done a bit more digging and have a reproducer for the recent
noref_elim_recurse assert, with what I know now the tree debug
messages may not be as useful.

Regarding the assert stuff, its a bit of a can of worms, the
documentation in the build system is misleading, when it was
written the idea seems to have been to have debug and release
builds, but Fedora/rpm distros didn't follow that.

Since then it looks like most packages have moved to assert(3),
being active for all builds. So perhaps its better to keep it
that way and remove some of the unused DEBUG options from the
docs and build scripts.