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. Glen
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