Date: Thu, 18 Jul 2013 16:40:42 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com>, Adrian Chadd <adrian@FreeBSD.org> Cc: freebsd-fs@FreeBSD.org Subject: Re: Deadlock in nullfs/zfs somewhere Message-ID: <51E7F05A.5020609@FreeBSD.org> In-Reply-To: <20130718112814.GA5991@kib.kiev.ua> References: <CAJ-Vmomy3MrkSwJLQUGnDuD3EC3HzrudEghSDMeDwzVdaFNpLg@mail.gmail.com> <51DCFEDA.1090901@FreeBSD.org> <CAJ-VmokctCmV4%2By17uvqO9wXEyh0s%2BaXZ9nggvoAgP5%2BZHSgFA@mail.gmail.com> <51E59FD9.4020103@FreeBSD.org> <CAJ-VmokR8jJpdRc_kBJzhW4_R1pJnj3UPfsG5ANpq-kEGwCP9g@mail.gmail.com> <51E67F54.9080800@FreeBSD.org> <CAJ-Vmonk2HAzX38-mbL8hwxiUfL6JyJrMTq0dTBctW=P4dfyEQ@mail.gmail.com> <51E7B686.4090509@FreeBSD.org> <20130718112814.GA5991@kib.kiev.ua>
next in thread | previous in thread | raw e-mail | index | archive | help
on 18/07/2013 14:28 Konstantin Belousov said the following:
> Well, I have no opinion. Making the fs suspended, in other words, preventing
> writers from entering the filesystem code, is probably good. I do not
> know zfs code to usefully comment on the approach.
OK, fair.
> Note that you must drain existing writers, i.e. call vfs_write_suspend(),
> to set MNTK_SUSPEND.
Here is my take on it, not tested at all.
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
index 0fc59cc..59c8cbd 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
@@ -2263,8 +2263,12 @@ zfs_suspend_fs(zfsvfs_t *zfsvfs)
{
int error;
- if ((error = zfsvfs_teardown(zfsvfs, B_FALSE)) != 0)
+ if ((error = vfs_write_suspend(zfsvfs->z_vfs)) != 0)
return (error);
+ if ((error = zfsvfs_teardown(zfsvfs, B_FALSE)) != 0) {
+ vfs_write_resume(mp, 0);
+ return (error);
+ }
dmu_objset_disown(zfsvfs->z_os, zfsvfs);
return (0);
@@ -2339,5 +2343,6 @@ bail:
rrw_exit(&zfsvfs->z_teardown_lock, FTAG);
+ vfs_write_resume(mp, 0);
if (err) {
/*
* Since we couldn't reopen zfsvfs::z_os, or
--
Andriy Gapon
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?51E7F05A.5020609>