From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E175364032 for ; Wed, 19 Nov 2025 19:23:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763580197; cv=none; b=q3JLHmvsQwGXKuSNS3QSgYcdhCN9OtPNyY/2AKVko4B//ovFpoQoWK5gqT6RAR3WWsX09EaNXb9PMdYwbjiA+oc0dSYBJDOJvXwjTBP7TkbHBO+qC1vwq53KO7ZxAqLJA/pRvwjVr5ETObvn4CcH9zvL5DBd1c9D3HegfbNMy+c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763580197; c=relaxed/simple; bh=gUR9v/9unllLq1t37JgWCn4XWzvHtKN4OQyOgp+WnA4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=NsHJ582wbZemfb+2sbUEQIBgc0b/Ki2vOi9z2KNcZI4FO/rYuNmpWHG+iMcwNsmmT/oTZrkgNWqC9/UIGG6bUzPi6vHXgXJXwcdCNUOvUsb2Jys3Lf0OdSpu27JMp0z9DFOC+4xADhD5QIhbDQhE9iuWAH+H/Aa8L43cH2/DtwY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y1cpRByJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Y1cpRByJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD048C4AF09; Wed, 19 Nov 2025 19:23:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763580196; bh=gUR9v/9unllLq1t37JgWCn4XWzvHtKN4OQyOgp+WnA4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Y1cpRByJ1/uOv0qrr+46FhNwejk0saux2/DV7PaG+WtUpTXNn0Ak+9NQlVayE/rKM zS6j1hqVFj0G//ZuNJIx/TMEdsyX0LozCLBmWtt0IRj5u7jvvm19ZyzIDsWLUsjJxk z4l3tVUFCXxSJtX8+5YZsGEiO/j2fW12IZhl6W3/6pE2XQFJjgTW5DUIEtAofVG/lH HeVorlCs0f0qpmoY/Y2daVAVfY3eEn9iZmOOxhCiCNGQ/PFwfP6dvlogCXkFgJfphQ SS9V3QN89chynumP4dV2bQGlCr/C7pr52Czz7iZ6Pe9FWudFtpQSnpXjTn4YKFbiAn uDI9hvdOESyuA== Message-ID: Subject: Re: [PATCH v5 03/11] nfsd: simplify foreign-filehandle handling to better match RFC-7862 From: Jeff Layton To: NeilBrown , Chuck Lever Cc: Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org Date: Wed, 19 Nov 2025 14:23:14 -0500 In-Reply-To: <20251119033204.360415-4-neilb@ownmail.net> References: <20251119033204.360415-1-neilb@ownmail.net> <20251119033204.360415-4-neilb@ownmail.net> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 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the COPY v4.2 op is used in the inter-server copy mode, the file > handle of the source file (presented as the saved filehandle to COPY) > is for a different ("foreign") file server which would not be expected > to be understood by this server. fh_verify() might return nfserr_stale > or nfserr_badhandle. >=20 > In order of this filehandle to still be available to COPY, both PUTFH > and SAVEFH much not trigger an error. >=20 > RFC 7862 section 15.2.3 says: >=20 > If the request is for an inter-server copy, the source-fh is a > filehandle from the source server and the COMPOUND procedure is being > executed on the destination server. In this case, the source-fh is a > foreign filehandle on the server receiving the COPY request. If > either PUTFH or SAVEFH checked the validity of the filehandle, the > operation would likely fail and return NFS4ERR_STALE. >=20 > If a server supports the inter-server copy feature, a PUTFH followed > by a SAVEFH MUST NOT return NFS4ERR_STALE for either operation. > These restrictions do not pose substantial difficulties for servers. > CURRENT_FH and SAVED_FH may be validated in the context of the > operation referencing them and an NFS4ERR_STALE error returned for an > invalid filehandle at that point. >=20 > [The RFC neglects the possibility of NFS4ERR_BADHANDLE] >=20 > Linux nfsd currently takes a different approach. Rather than just > checking for "a PUTFH followed by a SAVEFH", it goes further to consider > only that case when this filehandle is then used for COPY, and allows > that it might have been subject of RESTOREFH and SAVEFH in between. >=20 > This is not a problem in itself except for the extra code with little > benefit. This analysis of the COMPOUND to detect PUTFH ops which need > care is performed on every COMPOUND request, which is not necessary. >=20 > It is sufficient to check if the relevant conditions are met only when a > PUTFH op actually receives an error from fh_verify(). >=20 > This patch removes the checking code from common paths and places it in > nfsd4_putfh() only when fh_verify() returns a relevant error. >=20 > Rather than scanning ahead for a COPY, this patch notes (in > nfsd4_compoundargs) when an inter-server COPY is decoded, and in that > case only checks the next op to see if it is SAVEFH as this is what the > RFC requires. >=20 > A test on "inter_copy_offload_enable" is also added to be completely > consistent with the "If a server supports the inter-server copy feature" > precondition. >=20 > As we do this test in nfsd4_putfh() there is no now need to mark the > putfh op as "no_verify". >=20 > Signed-off-by: NeilBrown > --- > fs/nfsd/nfs4proc.c | 64 ++++++++++++++++------------------------------ > fs/nfsd/nfs4xdr.c | 2 +- > fs/nfsd/xdr4.h | 2 +- > 3 files changed, 24 insertions(+), 44 deletions(-) >=20 Reviewed-by: Jeff Layton