On Mon, 15 Mar 2010 18:31:28 -0400 Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote: > On Mon, 2010-03-15 at 17:39 -0400, Jeff Layton wrote: > > When a file is opened with O_TRUNC, the truncate processing is handled > > by handle_truncate(). This function however doesn't receive any info > > about the newly instantiated filp, and therefore can't pass that info > > along so that the setattr can use it. > > > > This makes NFSv4 misbehave. The client does an open and gets a valid > > stateid, and then doesn't use that stateid on the subsequent truncate. > > It uses the zero-stateid instead. Most servers ignore this fact and > > just do the truncate anyway, but some don't like it (notably, RHEL4). > > > > It seems more correct that since we have a fully instantiated file at > > the time that handle_truncate is called, that we pass that along so > > that the truncate operation can properly use it. > > At least in the O_CREAT|O_TRUNC case, we really should modify > nfs4_opendata_alloc() to set the attrs.ia_size to zero, so that the > server does an atomic open(O_CREAT|O_TRUNC) for us (see the DESCRIPTION > paragraph in RFC3530 section 14.2.16). There shouldn't be any need for > an extra truncate RPC call. > > Plain open(O_TRUNC) probably does need something along the lines of what > you propose, however. > Yeah that would be cleaner on the wire for the create case. It's not clear to me how to implement that though. There doesn't appear to be a straightforward way to tell the VFS to skip the truncate. -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
