Date: Sun, 20 Jul 1997 16:56:46 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: dk+@ua.net Cc: toor@dyson.iquest.net, freebsd-current@FreeBSD.ORG, sia@nest.org Subject: Re: -current :) Message-ID: <199707202356.QAA10117@phaeton.artisoft.com> In-Reply-To: <199707192216.PAA21949@dog.farm.org> from "Dmitry Kohmanyuk" at Jul 19, 97 03:16:29 pm
next in thread | previous in thread | raw e-mail | index | archive | help
> > > According to Satoshi Asami: > > > > I think they are mainly on the client side. What I've seen are a > > > > string of ^@ bytes inserted in files I save from rmail. (I now don't > > > > save mail at school. ;) > > this is in 2.2-tree also. (I just wrote mail about this to -hackers.) > > > > I t is not NFS-related but each time my INN 1.5.1 processes a newgroup > > > control message, my active file ands up with a whole page of ^@ and then > > > the new group(s) appear after it. > > > > > > Probably MMAP related as ACT_STYLE is MMAP in my config.data file. > > > > > > John, any idea ? > > > > > I have checked the code over and over and over again. I sure wish we > > had a repeatable example :-(. > > this _exactly_ (zero-filled page in active, then new newsgroups) happened > to me on our news server running 2.2.1-RELEASE. So, it should be old code. I have to say that I believe that this is not an NFS specific problem. As I said, I have been able to repeat it with an app *not* using mmap() at all, and *not* over NFS. The app was "vi". I *truly* believe that the page containing a frag is not being marked dirty, and therefore is not allocated or written. This is in the append case. Obviously, if the file size were updated, and the frag was not, a zero-fill would occur on read, just like with sparse blocks. The operation which should have "dirtied" the block is a write to a frag. One thing to note is that I am running 8k FS blocks; as a result, my frag size is 1024 bytes. This is double the block size, and it may be related to the problem. All the problems have occurred when the entire file is a frag, and is extended and remains in the same frag... ie: my file was 40 or so characters in length and was only grown by 6 characters (I changed the configuration file name for slapd). Before Nate jumps in and starts screaming "TerryBSD! TerryBSD!" at the top of his electronic lungs, as he is wont to do, the problem repeated on stock kernels. The problem did *not* repeat on a vanilla 2.2 stock kernel, however. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199707202356.QAA10117>