From: Chuck Lever <cel@kernel.org>
To: 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>
Cc: linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Chuck Lever <chuck.lever@oracle.com>
Subject: [PATCH v5 0/7] Automatic NFSv4 state revocation on filesystem unmount
Date: Thu, 26 Mar 2026 13:55:19 -0400 [thread overview]
Message-ID: <20260326-umount-kills-nfsv4-state-v5-0-d2ce071b3570@oracle.com> (raw)
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.
---
Changes since v4:
- 1/9 has been queued in nfsd-testing
- Split single NFSD_CMD_UNLOCK into three separate commands
- UNLOCK_EXPORT takes path only, no client attribute to avoid
auth_domain naming complexity with use_ipaddr
Changes since v3:
- All VFS changes replaced with new netlink "unlock" operation
Changes since v2:
- Replace fs_pin with an SRCU umount notifier chain in VFS
- Merge the pending COPY cancellation patch
- Replace xa_cmpxchg() with xa_insert()
- Use cancel_work_sync() instead of flush_workqueue()
- Remove rcu_barrier()
- Correct misleading claims in kdoc comments and commit messages
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 (7):
NFSD: Extract revoke_one_stid() utility function
NFSD: Add NFSD_CMD_UNLOCK_IP netlink command
NFSD: Add NFSD_CMD_UNLOCK_FILESYSTEM netlink command
NFSD: Replace idr_for_each_entry_ul in find_one_sb_stid()
NFSD: Track svc_export in nfs4_stid
NFSD: Add NFSD_CMD_UNLOCK_EXPORT netlink command
NFSD: Close cached file handles when revoking export state
Documentation/netlink/specs/nfsd.yaml | 61 +++++++++
fs/nfsd/filecache.c | 46 +++++++
fs/nfsd/filecache.h | 1 +
fs/nfsd/netlink.c | 36 ++++++
fs/nfsd/netlink.h | 3 +
fs/nfsd/nfs4layouts.c | 2 +
fs/nfsd/nfs4state.c | 226 +++++++++++++++++++++++-----------
fs/nfsd/nfsctl.c | 126 ++++++++++++++++++-
fs/nfsd/state.h | 6 +
fs/nfsd/trace.h | 32 ++++-
include/uapi/linux/nfsd_netlink.h | 24 ++++
11 files changed, 484 insertions(+), 79 deletions(-)
---
base-commit: 65058e9e9b20619f920397f529072e853dd43811
change-id: 20260318-umount-kills-nfsv4-state-138218f2f4e0
Best regards,
--
Chuck Lever
next reply other threads:[~2026-03-26 17:55 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-26 17:55 Chuck Lever [this message]
2026-03-26 17:55 ` [PATCH v5 1/7] NFSD: Extract revoke_one_stid() utility function Chuck Lever
2026-03-27 5:26 ` kernel test robot
2026-03-27 5:56 ` kernel test robot
2026-03-27 10:08 ` kernel test robot
2026-03-27 11:13 ` kernel test robot
2026-03-27 12:00 ` Jeff Layton
2026-03-27 12:21 ` Jeff Layton
2026-03-27 14:18 ` Chuck Lever
2026-03-26 17:55 ` [PATCH v5 2/7] NFSD: Add NFSD_CMD_UNLOCK_IP netlink command Chuck Lever
2026-03-27 12:06 ` Jeff Layton
2026-03-27 15:19 ` Chuck Lever
2026-03-27 15:52 ` Jeff Layton
2026-03-27 16:02 ` Chuck Lever
2026-03-26 17:55 ` [PATCH v5 3/7] NFSD: Add NFSD_CMD_UNLOCK_FILESYSTEM " Chuck Lever
2026-03-26 17:55 ` [PATCH v5 4/7] NFSD: Replace idr_for_each_entry_ul in find_one_sb_stid() Chuck Lever
2026-03-26 17:55 ` [PATCH v5 5/7] NFSD: Track svc_export in nfs4_stid Chuck Lever
2026-03-26 17:55 ` [PATCH v5 6/7] NFSD: Add NFSD_CMD_UNLOCK_EXPORT netlink command Chuck Lever
2026-03-26 17:55 ` [PATCH v5 7/7] NFSD: Close cached file handles when revoking export state Chuck Lever
2026-03-27 12:03 ` [PATCH v5 0/7] Automatic NFSv4 state revocation on filesystem unmount Jeff Layton
2026-03-27 13:29 ` Chuck Lever
2026-03-27 12:18 ` Jeff Layton
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