From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: Date: Thu, 7 Jul 2005 06:38:51 -0400 From: Russ Cox To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu> Subject: Re: [9fans] afid and fd, mapping from user space In-Reply-To: <37ef730aacf5a0b86b77caaa538afd8d@vitanuova.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline References: <599f06db050701152062c908fe@mail.gmail.com> <37ef730aacf5a0b86b77caaa538afd8d@vitanuova.com> Topicbox-Message-UUID: 62a0412e-ead0-11e9-9d60-3106f5b1d025 As long as you don't use it for such things (i.e. use it for a real file system and don't depend on atomic stuff like locks) I don't see a problem. I used it in 3e for quite a while and never had any problems. I had to use special bindings to make sure I didn't try to deliver mail over it, but other than that it was great. Russ On 7/6/05, rog@vitanuova.com wrote: > > I am porting Recover to 4e. Recover is a filesystem which speaks > > 9P with two ends, a server and a client. When a connection falls down > > it pushes the state and restarts the pending requests, so you don't > > see a hung channel any more if your connection falls down. >=20 > i did something like this for inferno, but couldn't work out what was > the best thing to do about non-idempotent 9p transactions: if the > connection is lost before the reply to such a transaction is received, > what is the correct course of action? the client can't know whether the > transaction has actually taken place on the server. >=20 > examples of such requests: >=20 > create > wstat (rename) > write to an append-only file > any operation on a non-standard filesystem (e.g. writing a ctl fi= le) >=20 > problems arising from this kind of thing will be > rare, but all the more insidious when they do actually happen. >=20 > in the end, i decided to make such requests yield Rerror("operation possi= bly failed"), > but i have a niggling feeling that the whole approach is wrong. >=20 > thoughts? >=20 >