From: Christian Brauner <brauner@kernel.org>
To: Chuck Lever <cel@kernel.org>
Cc: NeilBrown <neil@brown.name>, Jeff Layton <jlayton@kernel.org>,
Olga Kornievskaia <okorniev@redhat.com>,
Dai Ngo <Dai.Ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Chuck Lever <chuck.lever@oracle.com>
Subject: Re: [PATCH v9 0/9] Automatic NFSv4 state revocation on filesystem unmount
Date: Tue, 21 Apr 2026 14:00:11 +0200 [thread overview]
Message-ID: <20260421-aufpassen-erfuhren-93a4238cb71b@brauner> (raw)
In-Reply-To: <20260419-umount-kills-nfsv4-state-v9-0-0660bd06d2b6@oracle.com>
On Sun, Apr 19, 2026 at 02:52:58PM -0400, Chuck Lever wrote:
> 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_ip and
> /proc/fs/nfsd/unlock_fs procfs interfaces handle this, but have
> no netlink equivalents, and unlock_fs operates at whole-superblock
> granularity.
>
> This series adds three new NFSD netlink commands, each with its own
> attribute set:
>
> - NFSD_CMD_UNLOCK_IP releases NLM locks held by a client IP
> address. Netlink equivalent of write_unlock_ip.
>
> - NFSD_CMD_UNLOCK_FILESYSTEM revokes all NFS state on a
> superblock. Netlink equivalent of write_unlock_fs.
>
> - NFSD_CMD_UNLOCK_EXPORT revokes NFSv4 state acquired through
> exports of a specific path, regardless of client.
>
> UNLOCK_FILESYSTEM and UNLOCK_EXPORT serve different intents.
> UNLOCK_FILESYSTEM means "unmounting /data, release everything
> on this superblock." UNLOCK_EXPORT means "no clients remain for
> /data/projectA, release only the state acquired through exports
> of that path." Userspace (exportfs -u) sends UNLOCK_EXPORT after
> removing the last client for a given path, enabling the underlying
> filesystem to be unmounted.
>
> The path-only design for UNLOCK_EXPORT avoids the auth_domain
> naming complexity (use_ipaddr vs hostname-based domains) by not
> requiring the caller to identify a specific client. Since this
> mechanism is to be used to enable umount, this seemed like a
> reasonable compromise.
Thanks for moving this into nfsd itself. That's great to see.
prev parent reply other threads:[~2026-04-21 12:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-19 18:52 [PATCH v9 0/9] Automatic NFSv4 state revocation on filesystem unmount Chuck Lever
2026-04-19 18:52 ` [PATCH v9 1/9] NFSD: Fix infinite loop in layout state revocation Chuck Lever
2026-04-19 18:53 ` [PATCH v9 2/9] NFSD: Handle layout stid in nfsd4_drop_revoked_stid() Chuck Lever
2026-04-19 18:53 ` [PATCH v9 3/9] NFSD: Extract revoke_one_stid() utility function Chuck Lever
2026-04-19 18:53 ` [PATCH v9 4/9] NFSD: Add NFSD_CMD_UNLOCK_IP netlink command Chuck Lever
2026-04-19 18:53 ` [PATCH v9 5/9] NFSD: Add NFSD_CMD_UNLOCK_FILESYSTEM " Chuck Lever
2026-04-19 18:53 ` [PATCH v9 6/9] NFSD: Replace idr_for_each_entry_ul in find_one_sb_stid() Chuck Lever
2026-04-19 18:53 ` [PATCH v9 7/9] NFSD: Track svc_export in nfs4_stid Chuck Lever
2026-04-19 18:53 ` [PATCH v9 8/9] NFSD: Add NFSD_CMD_UNLOCK_EXPORT netlink command Chuck Lever
2026-04-19 18:53 ` [PATCH v9 9/9] NFSD: Close cached file handles when revoking export state Chuck Lever
2026-04-21 12:00 ` Christian Brauner [this message]
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