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 008F91D5CFE; Thu, 8 Jan 2026 00:40:21 +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=1767832823; cv=none; b=L4vtnWMri5J1BY65ZKPnfrxBjhA+AuIxdbAEPhiLA+BDAbtlYj1ktDQrUooVRd0s+4zO6VKtY+gn3K60o4i/pn8nhKxG7MV2ZmqDScyID8uHA8j+2BE2TgFSa7PvjIB7gv2W0WsRt77puFVH6ZJmRe2hRNOwFFFNpORpAsTGFDM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767832823; c=relaxed/simple; bh=lCr25JyiroJH9anX4xgULqRLmslXynO4tD06DKJ6+m4=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=Wdw1yNoTsohKMpoiIer0zg5dEIRPAApZuA5QCqgEvzU5TYT7Z34KCT7KwKaaBt5Lfpwc4PDCq98jeSJDcBp/wJoCqGtTfxmAgZU8FleoQsgfWxkc7Et7J2ECPRBJwkcyP0cCpvyD8kpZN+rgiTH/ugiKgxwPIaJlxFA2IsV6MSI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=l8R8efoU; 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="l8R8efoU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7177AC4CEF1; Thu, 8 Jan 2026 00:40:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767832821; bh=lCr25JyiroJH9anX4xgULqRLmslXynO4tD06DKJ6+m4=; h=From:To:Cc:Subject:Date:From; b=l8R8efoUE8nGyhbuO8Umg4YjMmNgZeYb5NwJjC3xSR5IaBfva/SjiFHTzY+c/5OIT ZfqVrT6S1yJ4H4P03DAYc/NK834Ocl9U3Zgd1SPf6NUXI9H4iBK0rp2EJsGoyImHpT l5Kj7s8/GbuqXd0W18mO++/6TpqMzEPs6OxnMLBLdYEcPKlsjPUx9A+vM3OQL9YRvm rMEc5VB32dQDFUDcPpSl0ATe7GkBcSTTuP9/SOPb59qSVm0DpnevMBghED1nsR1d2c hDb4vpwiz4Hpe+ypDNApdPj2dBuxOzOBOeYtnC90uy38g4JMmbwtoXkhDslsWkWUwp nAG8rVG1sJeWA== From: Chuck Lever To: NeilBrown , Jeff Layton , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: , , Chuck Lever Subject: [PATCH v2 0/6] Automatic NFSv4 state revocation on filesystem unmount Date: Wed, 7 Jan 2026 19:40:10 -0500 Message-ID: <20260108004016.3907158-1-cel@kernel.org> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chuck Lever When an NFS server exports a filesystem and clients hold NFSv4 state (opens, locks, delegations), unmounting the underlying filesystem fails with EBUSY. The /proc/fs/nfsd/unlock_fs interface exists for administrators to manually revoke state before retrying the unmount, but this approach has significant operational drawbacks. Manual intervention breaks automation workflows. Containerized NFS servers, orchestration systems, and unattended maintenance scripts cannot reliably unmount exported filesystems without implementing custom logic to detect the failure and invoke unlock_fs. System administrators managing many exports face tedious, error-prone procedures when decommissioning storage. This series enables the NFS server to detect filesystem unmount events and automatically revoke associated state. The mechanism uses the kernel's existing fs_pin infrastructure, which provides callbacks during mount lifecycle transitions. When a filesystem is unmounted, all NFSv4 opens, locks, and delegations referencing it are revoked, async COPY operations are cancelled with NFS4ERR_ADMIN_REVOKED sent to clients, NLM locks are released, and cached file handles are closed. With automatic revocation, unmount operations complete without administrator intervention once the brief state cleanup finishes. Clients receive immediate notification of state loss through standard NFSv4 error codes, allowing applications to handle the situation appropriately rather than encountering silent failures. Based on the nfsd-testing branch of: https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/ Changes since v1: - Explain why drop_client() is being renamed - Finish implementing revocation on umount - Rename pin_insert_group - Clarified log output and code comments - Hold nfsd_mutex while closing nfsd_files Chuck Lever (6): nfsd: cancel async COPY operations when admin revokes filesystem state fs: export pin_insert and pin_remove for modular filesystems fs: add pin_insert_sb() for superblock-only pins fs: invoke group_pin_kill() during mount teardown nfsd: revoke NFSv4 state when filesystem is unmounted nfsd: close cached files on filesystem unmount fs/fs_pin.c | 50 ++++++++ fs/namespace.c | 2 + fs/nfsd/Makefile | 2 +- fs/nfsd/filecache.c | 44 +++++++ fs/nfsd/filecache.h | 1 + fs/nfsd/netns.h | 4 + fs/nfsd/nfs4proc.c | 124 +++++++++++++++++-- fs/nfsd/nfs4state.c | 46 +++++-- fs/nfsd/nfsctl.c | 11 +- fs/nfsd/pin.c | 274 +++++++++++++++++++++++++++++++++++++++++ fs/nfsd/state.h | 9 ++ fs/nfsd/xdr4.h | 1 + include/linux/fs_pin.h | 1 + 13 files changed, 548 insertions(+), 21 deletions(-) create mode 100644 fs/nfsd/pin.c -- 2.52.0