Date: Thu, 22 Feb 2007 12:38:11 -0500 From: John Baldwin <jhb@freebsd.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/kern vfs_syscalls.c Message-ID: <200702221238.11641.jhb@freebsd.org> In-Reply-To: <20070222171720.GI39168@deviant.kiev.zoral.com.ua> References: <200702191056.l1JAuASc059200@repoman.freebsd.org> <200702201122.00390.jhb@freebsd.org> <20070222171720.GI39168@deviant.kiev.zoral.com.ua>
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On Thursday 22 February 2007 12:17, Kostik Belousov wrote: > 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). What would be nice would be to have a kern_getdirentries() that took a function pointer that took a directory record and did the actual conversion + UIO so we could cut down on the duplicated code. -- John Baldwin
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