From: David Howells <dhowells@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linuxram@us.ibm.com, jamie@shareable.org,
viro@parcelfarce.linux.theplanet.co.uk, akpm@osdl.org,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] fix race in mark_mounts_for_expiry()
Date: Wed, 18 May 2005 12:51:39 +0100 [thread overview]
Message-ID: <9498.1116417099@redhat.com> (raw)
In-Reply-To: <E1DYMVf-0000hD-00@dorka.pomaz.szeredi.hu>
Miklos Szeredi <miklos@szeredi.hu> wrote:
> Do you think my original fix is wrong, or is this just cosmetics?
What you're doing is tricky. It's asking for a race. Admittedly, it may not
occur in the particular situation you're looking at, but can you always
guarantee that? Remember, it may be a race against some piece of code that's
not yet written, by an author who doesn't realise what _you_ are doing here
because their changeset doesn't intersect with yours.
Remember: you have, in effect, made the usage count on that structure
non-atomic.
I do something like that in rwsems and it's something I have to be very
careful about. The main reason I can get away with it is that the actual
implementation of rwsems is small and is located in a very restrictes set of
places and it's not intermingled with other stuff.
David
next prev parent reply other threads:[~2005-05-18 11:52 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-13 10:44 [PATCH] namespace.c: fix bind mount from foreign namespace Miklos Szeredi
2005-05-13 16:49 ` Ram
2005-05-13 17:06 ` Al Viro
2005-05-13 17:17 ` Miklos Szeredi
2005-05-13 17:25 ` Al Viro
2005-05-13 17:34 ` Miklos Szeredi
2005-05-13 17:29 ` Ram
2005-05-13 18:40 ` Miklos Szeredi
[not found] ` <1116012287.6248.410.camel@localhost>
[not found] ` <E1DWfqJ-0004eP-00@dorka.pomaz.szeredi.hu>
[not found] ` <1116013840.6248.429.camel@localhost>
2005-05-14 6:11 ` Miklos Szeredi
2005-05-16 15:11 ` Ram
2005-05-16 8:44 ` Miklos Szeredi
2005-05-16 8:59 ` Miklos Szeredi
2005-05-16 11:26 ` Jamie Lokier
2005-05-16 13:23 ` Miklos Szeredi
2005-05-16 11:14 ` Jamie Lokier
2005-05-17 3:50 ` Ram
2005-05-16 20:15 ` Miklos Szeredi
2005-05-17 1:28 ` Jamie Lokier
2005-05-17 5:34 ` Miklos Szeredi
[not found] ` <1116360352.24560.85.camel@localhost>
[not found] ` <E1DYI0m-0000K5-00@dorka.pomaz.szeredi.hu>
[not found] ` <1116399887.24560.116.camel@localhost>
[not found] ` <1116400118.24560.119.camel@localhost>
2005-05-18 9:51 ` [PATCH] fix race in mark_mounts_for_expiry() Miklos Szeredi
2005-05-18 10:32 ` David Howells
2005-05-18 10:37 ` Miklos Szeredi
2005-05-18 10:46 ` David Howells
2005-05-18 10:53 ` Miklos Szeredi
2005-05-18 11:07 ` Trond Myklebust
2005-05-18 11:32 ` Miklos Szeredi
2005-05-18 12:50 ` Jamie Lokier
2005-05-18 13:21 ` Miklos Szeredi
2005-05-18 17:34 ` Jamie Lokier
2005-05-18 19:05 ` Miklos Szeredi
2005-05-18 19:52 ` Jamie Lokier
2005-05-19 12:41 ` Miklos Szeredi
2005-05-18 10:59 ` David Howells
2005-05-18 11:14 ` Miklos Szeredi
2005-05-18 11:51 ` David Howells [this message]
2005-05-18 12:08 ` Miklos Szeredi
2005-05-18 12:33 ` Miklos Szeredi
2005-05-18 16:53 ` Miklos Szeredi
2005-05-18 18:47 ` Ram
2005-05-18 19:19 ` Miklos Szeredi
2005-05-18 20:35 ` Ram
2005-05-19 12:52 ` Miklos Szeredi
2005-05-17 18:48 ` [PATCH] namespace.c: fix bind mount from foreign namespace Ram
2005-05-17 0:00 ` Jamie Lokier
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