Am 08.03.2016 um 04:37 schrieb Benjamin Kaduk: >>> There >>> > > are many call paths in the cache manager that end up at this function, >>> > > most of which are not prepared to properly handle an ERESTARTSYS >>> > > return. >>> > > Since this status can be returned after some data has already been >>> > > written, the correct behavior upon receiving it is far from clear ... >>> > > a >>> > > path towards a client free of this vector for data corruption may >>> > > involve >>> > > avoiding the dependence on splice_from_pipe_next() in preference to >>> > > adopting all call sites to handle the ERSTARTSYS case. >> > >> > For the 1.6 release, this seems the best choice of action. The "real" >> > fix would likely be difficult to completely test in a timely fashion. > That only helps if we know what the replacement would be...I am not a > linux VFS expert and do not have any ideas right now.
I am not a kernel/driver developer nor a file system developer. So please forgive, if the following makes no sense at all. As far as I understand the issue and the openafs sources, the problem arises as afs_linux_storeproc uses the splice api that can return ERESTARTSYS as of kernel version 4.4. A quick search in the NEWS file and git logs suggests that afs_linux_storeproc was introduced in OpenAFS 1.5.69 (2010-01-19) as a performance improvement: " Linux * Use splice to speed up storing files." The original behaviour which uses seperate reads/writes instead of splice and that is (still) used on non-linux systems remained in afs_GenericStoreProc in src/afs/afs_fetchstore.c . So my question is: Is it possible to rereplace afs_linux_storeproc with afs_GenericStoreProc on linux kernel versions >=4.4 as a temporary solution to the issue either in the openafs sources or as a distribution specific patch, trading some performance for data integrity? Denis -- Karlsruher Institut für Technologie (KIT) IPD Snelting Denis Lohner wissenschaftlicher Mitarbeiter Am Fasanengarten 5, Gebäude 50.34, Raum 025 76131 Karlsruhe Telefon: +49 721 608-47399 Fax: +49 721 608-48457 E-Mail: denis.loh...@kit.edu Web: pp.ipd.kit.edu KIT – Die Forschungsuniversität in der Helmholtz-Gemeinschaft Das KIT ist seit 2010 als familiengerechte Hochschule zertifiziert.
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