Date: Sun, 21 Jul 2013 12:36:43 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: freebsd-fs@FreeBSD.org Subject: Re: Deadlock in nullfs/zfs somewhere Message-ID: <51EBABAB.5040808@FreeBSD.org> In-Reply-To: <20130721071124.GY5991@kib.kiev.ua> References: <CAJ-Vmonk2HAzX38-mbL8hwxiUfL6JyJrMTq0dTBctW=P4dfyEQ@mail.gmail.com> <51E7B686.4090509@FreeBSD.org> <20130718112814.GA5991@kib.kiev.ua> <51E7F05A.5020609@FreeBSD.org> <20130718185215.GE5991@kib.kiev.ua> <51E91277.3070309@FreeBSD.org> <20130719103025.GJ5991@kib.kiev.ua> <51E95CDD.7030702@FreeBSD.org> <20130719184243.GM5991@kib.kiev.ua> <51E99477.1030308@FreeBSD.org> <20130721071124.GY5991@kib.kiev.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
on 21/07/2013 10:11 Konstantin Belousov said the following: > On Fri, Jul 19, 2013 at 10:33:11PM +0300, Andriy Gapon wrote: >> on 19/07/2013 21:42 Konstantin Belousov said the following: >>> Then, you cannot use VFS suspension. Or, in other words, you are >>> directed to abuse the VFS interface. I assure you that any changes to >>> the interface would not take into account such abuse and probably break >>> your hack. >> >> So what would be your recommendation about this problem? Should we add >> another flavor of VFS suspension? The one that would mean "all external >> accesses to this fs must be put on hold", but would not imply "this fs is >> frozen". > > Suspension is very complicated as it is. Adding another flavour would > multiply the current mess^H^H^H^H collection of subtleties. IMO, the best > route is to use the KPI properly, i.e. adding the vn_start_write() braces > around the top-level entries in the mutating code paths. > So how will this help with doing a rollback in the thread that does the following? vfs_write_suspend zfs rollback vfs_write_resume -- Andriy Gapon
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?51EBABAB.5040808>