cvs commit: src/sys/kern vfs_syscalls.c

[Kostik Belousov]

On Tue, Feb 20, 2007 at 11:21:59AM -0500, John Baldwin wrote:
> On Tuesday 20 February 2007 09:49, Kostik Belousov wrote:
> > On Mon, Feb 19, 2007 at 06:39:58PM -0500, John Baldwin wrote:
> > > On Monday 19 February 2007 05:56, Konstantin Belousov wrote:
> > > > kib         2007-02-19 10:56:10 UTC
> > > > 
> > > >   FreeBSD src repository
> > > > 
> > > >   Modified files:
> > > >     sys/kern             vfs_syscalls.c 
> > > >   Log:
> > > >   Remove union_dircheckp hook, it is not needed by new unionfs code anymore.
> > > >   As consequence, getdirentries() no longer needs to drop/reacquire
> > > >   directory vnode lock, that would allow it to be reclaimed in between.
> > > 
> > > I think there is at least one more copy of getdirentries() under sys/compat,
> > > possibly multiple.  Are you going to fix this in all of them?
> > 
> > Could you, please, point out where is it ? My grep told me that I removed
> > all references to the union_dircheckp, and I think that getdirentries() code
> > had to have references to it. My change modified two syscalls: getdirentries()
> > and ogetdirentries().
> 
> Well, I did find at least 3 ABIs (Linux, svr4, and ibcs2) that do their own
> wrapper around VOP_READDIR(), but none of them had the union check in them.
As result, "mount -o union" does not work for compat binaries.

> Do you know why the ABIs use cookies for VOP_READDIR() but getdirentries()
> doesn't?
No, and it seems that cookies, as well as vfs_syscalls.c avoidance of cookies
(together with union_dircheckp) go back to at least 1994/1997 years, and
Lite-2 import (see commit logs for rev. 1.9 and 1.54 of vfs_syscalls.c).

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