Date: Fri, 21 May 2004 18:09:14 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: "David E. Cross" <crossd@cs.rpi.edu> Cc: wronkm@cs.rpi.edu Subject: Re: Journalled UFS Message-ID: <20040521160914.GE845@darkness.comp.waw.pl> In-Reply-To: <1084556769.2304.20.camel@kiki.cs.rpi.edu> References: <1084556769.2304.20.camel@kiki.cs.rpi.edu>
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On Fri, May 14, 2004 at 01:46:11PM -0400, David E. Cross wrote:
+> Ok... It was brought to my attention that someone was asking for this
+> again, so I figure its time to put out an update on the status.
Great to hear!
+> Here's what I want to do:
+>=20
+> VOP/VFS entry point {
+> Aquire Mutex with RECURSION;
mtx_lock(your_mtx);
+> If first aquire, inc transaction ID; else don't;
if (!mtx_recursed(your_mtx))
/* Inc transaction ID. */;
+> NORMAL VOP/VFS Dispatch;
+>=20
+> Release Mutex;
recursed =3D mtx_recursed(your_mtx);
mtx_unlock(your_mtx);
+> if last release && syn_journal Checkpoint_Routine;
if (!recursed && syn_journal)
Checkpoint_Routine;
+> }
+> Checkpoint_Routine {
+> Aquire mutex with RECURSION:
+> if first aquire, last_tid=3DTID;
+> else last_tid=3DTID-1;
+>=20
+> Dump_to last_tid;
+>=20
+> Release mutex;
+> }
+>=20
+> I am not sure how to check if we already have a mutex, and if its
+> recursion or not vs. the mutex is already aquired but its not "ours".
+> suggestions?
I'm not sure why you want to check if mutex is already acquired.
You don't want to sleep? You can use mtx_trylock(9) or mtx_owned(9) maybe.
--=20
Pawel Jakub Dawidek http://www.FreeBSD.org
pjd@FreeBSD.org http://garage.freebsd.pl
FreeBSD committer Am I Evil? Yes, I Am!
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