Date: Thu, 11 Aug 2016 23:13:17 +0000 From: Glen Barber <gjb@FreeBSD.org> To: Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: Andriy Gapon <avg@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: Re: svn commit: r303970 - in stable/11/sys/cddl: compat/opensolaris/sys contrib/opensolaris/uts/common/fs/zfs contrib/opensolaris/uts/common/fs/zfs/sys Message-ID: <20160811231317.GH51184@FreeBSD.org> In-Reply-To: <20160811230747.GJ8192@zxy.spb.ru> References: <201608112048.u7BKm4OH076291@repo.freebsd.org> <20160811223331.GF22212@zxy.spb.ru> <20160811223637.GE51184@FreeBSD.org> <20160811225202.GI8192@zxy.spb.ru> <20160811225723.GG51184@FreeBSD.org> <20160811230747.GJ8192@zxy.spb.ru>
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[-- Attachment #1 --] On Fri, Aug 12, 2016 at 02:07:47AM +0300, Slawa Olhovchenkov wrote: > On Thu, Aug 11, 2016 at 10:57:23PM +0000, Glen Barber wrote: > > > On Fri, Aug 12, 2016 at 01:52:02AM +0300, Slawa Olhovchenkov wrote: > > > On Thu, Aug 11, 2016 at 10:36:37PM +0000, Glen Barber wrote: > > > > > > > On Fri, Aug 12, 2016 at 01:33:31AM +0300, Slawa Olhovchenkov wrote: > > > > > On Thu, Aug 11, 2016 at 08:48:04PM +0000, Andriy Gapon wrote: > > > > > > > > > > > Author: avg > > > > > > Date: Thu Aug 11 20:48:03 2016 > > > > > > New Revision: 303970 > > > > > > URL: https://svnweb.freebsd.org/changeset/base/303970 > > > > > > > > > > > > Log: > > > > > > MFC r303763,303791,303869: zfs: honour and make use of vfs vnode locking protocol > > > > > > > > > > > > ZFS POSIX Layer is originally written for Solaris VFS which is very > > > > > > different from FreeBSD VFS. Most importantly many things that FreeBSD VFS > > > > > > manages on behalf of all filesystems are implemented in ZPL in a different > > > > > > way. > > > > > > Thus, ZPL contains code that is redundant on FreeBSD or duplicates VFS > > > > > > functionality or, in the worst cases, badly interacts / interferes > > > > > > with VFS. > > > > > > > > > > > > The most prominent problem is a deadlock caused by the lock order reversal > > > > > > of vnode locks that may happen with concurrent zfs_rename() and lookup(). > > > > > > The deadlock is a result of zfs_rename() not observing the vnode locking > > > > > > contract expected by VFS. > > > > > > > > > > > > This commit removes all ZPL internal locking that protects parent-child > > > > > > relationships of filesystem nodes. These relationships are protected > > > > > > by vnode locks and the code is changed to take advantage of that fact > > > > > > and to properly interact with VFS. > > > > > > > > > > > > Removal of the internal locking allowed all ZPL dmu_tx_assign calls to > > > > > > use TXG_WAIT mode. > > > > > > > > > > > > Another victim, disputable perhaps, is ZFS support for filesystems with > > > > > > mixed case sensitivity. That support is not provided by the OS anyway, > > > > > > so in ZFS it was a buch of dead code. > > > > > > > > > > > > To do: > > > > > > - replace ZFS_ENTER mechanism with VFS managed / visible mechanism > > > > > > - replace zfs_zget with zfs_vget[f] as much as possible > > > > > > - get rid of not really useful now zfs_freebsd_* adapters > > > > > > - more cleanups of unneeded / unused code > > > > > > - fix / replace .zfs support > > > > > > > > > > MFC to 10.x/9.x planed? > > > > > > > > > > > > > As I understand it, this does not affect stable/10. > > > > > > Sure? > > > I think ZFS/VFS layers don't change between 9.x and 11.x > > > > > > > No, but as I understand it, a commit to head tickled this bug. avg@ can > > correct me if I am wrong. > > May be I am wrong, I see messages about like issuses in 9.x/10.x. > As I understund this is more clear implementation. > Also, unification in 12.x/10.x take benefit for MFC other ZFS diffs. > I agree with you. I am just unsure if this particular bug affects 10.x and 9.x. Glen [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJXrQaNAAoJEAMUWKVHj+KT44IP/2p+8QbGfaZiZ5fmnGMNu3SO xByEFNL9WN8TlZWOXVH9FYgynD3AOlyU0il57+tNvbhUsfh2b1iwThMW0KUaDac8 zGptk97rzO2j5Oe5H3gAhlmk3jnKTAPbcBhAiFuzraLmAvGq/hLxnO4bE/kKkY4W Nzm0L9fOoeCcTE1YRgRobNIWP2WAtE+h5qwTMaww+dsI4dsPtfy2aRzQlbR47y3O k+h5S37vuE9FtX4cBTOmGvH1rmlRnKXJIm+awEAFWswfOVJ4tZCTSCWmmEIlDQ2K oEp68eLtzP3MlRdRVSSpznGNZZjWAGaoTYM+WGXrt+oennQbA6iHiYVNrp5kWg7e TQGwozz33Dx3FNpj4QtO0PQ82lHP4VeMNO9xODBrBYV4uQ8i5kol9heZ3Vm+hpf/ lxjFXvSGHuh55UUMXfffHEUZx2Sook07eKwwnBM3Ohbh+gtESCQmzaYWbtnY5CPk Mw3lF/msGwHGTz2KPIUuzhEzSQRYzz9mcOOT8HViK7kiWXL/2L3YFBiO7T9klfxw IORrn1Eq76x+FxW67rJVGYf5T0RALsy/lCVsd53KR2o6nzrsiDNMG/DTwNWoFy2J c52+gkgDeG0PdnFoJ9kTCL4IP6FMR0SvhkEc5I8PJGXpcOMnfpNBkO3TBVWOArby TipHoLUcDmFUgPiouOnb =BHb/ -----END PGP SIGNATURE-----
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