Messages in this thread | | | Subject | Re: [PATCH] vfs: pass struct file to do_truncate on O_TRUNC opens | From | Trond Myklebust <> | Date | Mon, 15 Mar 2010 18:31:28 -0400 |
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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.
Cheers Trond
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