Hi Trond-
As we discussed yesterday, I'm concerned about the test in
_nfs4_proc_open that uses the values of the cinfo.before and
cinfo.after fields without checking cinfo.atomic.
2288 if (o_arg->open_flags & O_CREAT) {
2289 if (o_arg->open_flags & O_EXCL)
2290 data->file_created = 1;
2291 else if (o_res->cinfo.before != o_res->cinfo.after)
2292 data->file_created = 1;
2293 if (data->file_created || dir->i_version != o_res->cinfo.after)
2294 update_changeattr(dir, &o_res->cinfo,
2295 o_res->f_attr->time_start);
2296 }
Line 2291 is the issue.
Suppose the server filesystem substitutes a weak ctime for
the change attribute. Sometimes when a file is successfully
created on the server, the ctime of the parent doesn't
change. This test then fails and leaves file_created set
to zero.
Later, nfs4_opendata_access looks at file_created. If not
set, the access check fails and open(2) returns EACCES as
a result, even though the file was created successfully
and OPEN returned NFS4_OK.
You mentioned that the server should set cinfo.atomic to
be false when a weak ctime is used as the change attribute.
Will that help in this case?
--
Chuck Lever
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