NFSD: Use xdrgen XDR functions for NFSv2 SETATTR procedure

Replace the NFSPROC_SETATTR entry in the nfsd_procedures2 array
with an entry that dispatches the xdrgen-generated
nfs_svc_decode_sattrargs and nfs_svc_encode_attrstat. Wrapper
structures bridge the generated xdrgen types and the legacy
svc_fh, iattr, and kstat representations the NFSD VFS layer still
uses. The result reuses the attrstat wrapper from the GETATTR
conversion; the new nfsd_sattr_to_iattr() and
nfsd_timeval_to_timespec64() helpers translate the decoded sattr
into the iattr that nfsd_setattr() consumes.

The hand-coded svcxdr_decode_sattr() rejects a time-useconds value
greater than one second before converting it, preventing the
microsecond-to-nanosecond multiplication from wrapping to a valid
but incorrect value on 32-bit platforms. nfsd_sattr_to_iattr()
preserves that range check. Because it runs after the generated
decoder rather than inside it, an out-of-range value fails the
procedure with nfserr_io rather than the RPC GARBAGE_ARGS the
hand-coded decoder returned.

The pc_argzero field is now set to zero for the NFSv2 SETATTR
procedure. The xdrgen decoders are trusted to initialize all
arguments in the argp->xdrgen field, making the early defensive
memset unnecessary. The remaining argp fields are cleared as
needed. The wrapper's iattr is one of them: nfsd_sattr_to_iattr()
zeroes the whole structure rather than only ia_valid, because the
nfsd_vfs_setattr tracepoint records ia_size, ia_uid, and ia_gid
whether or not their ATTR bits are set.

This refactor replaces the use of svcxdr_encode_fattr(), so the
reference to the file handle can be released directly by
nfsd_proc_setattr(). A separate ->pc_release callback is thus no
longer needed. This makes it straightforward to confirm that the
file handle is properly released during every error flow.

Acked-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260916162859.2051-11-cel@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>

0 files changed, 0 insertions, 0 deletions