lockd: Use xdrgen XDR functions for the NLMv3 TEST procedure

The NLM TEST procedure requires host and file lookups to check
lock state, operations that will be common across multiple NLM
procedures being migrated to xdrgen. Introducing the
nlm3svc_lookup_host() and nlm3svc_lookup_file() helpers now keeps
these common patterns in one place for subsequent conversions in
this series.

This patch converts the TEST procedure to use xdrgen functions
nlm_svc_decode_nlm_testargs and nlm_svc_encode_nlm_testres
generated from the NLM version 3 protocol specification. The
procedure handler is rewritten to use xdrgen types through wrapper
structures that bridge between generated code and the legacy
lockd_lock representation still used by the core lockd logic.

Setting pc_argzero to zero is safe because the generated decoder
fills the argp->xdrgen subfields before the procedure runs, so the
zeroing memset performed by the dispatch layer is not needed. The
lock member of the wrapper is populated explicitly in
nlm3svc_lookup_file() rather than relying on zero-initialization.

The conflicting holder's offset and length are saturated to
NLM_OFFSET_MAX when constructing the reply. A conflicting lock
established by an NLMv4 client or by a local process can sit
beyond the NLMv3 signed 32-bit range, and copying fl_start and
fl_end straight into the unsigned 32-bit XDR fields would wrap
and report a bogus range. The previous hand-written encoder in
svcxdr_encode_holder() used loff_t_to_s32() for the same reason,
but this patch series intends to separate the concerns of data
conversion (XDR) from dealing with local byte range constraints,
so clamping is hoisted into the proc function.

The previous hand-written decoder in svcxdr_decode_cookie()
rewrote a zero-length NLM cookie into a four-byte zero cookie,
with a comment attributing the substitution to HP-UX clients.
The xdrgen-generated netobj decoder performs no such rewrite, so
a zero-length request cookie now round-trips unchanged into the
reply. HP-UX has reached end of support, and NLM_TEST reply
matching relies on the RPC XID rather than the NLM cookie, so
the workaround is dropped intentionally here.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

0 files changed, 0 insertions, 0 deletions