6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton [ Upstream commit 09ea3eb9a518565f5bca386e81b993ed8825f5e8 ] clients_still_reclaiming() computes a deadline from nn->boot_time (CLOCK_REALTIME, ~1.7 billion) but compares it against ktime_get_boottime_seconds() (CLOCK_BOOTTIME, seconds since boot). The comparison is always false — it would take ~54 years of uptime for BOOTTIME to exceed the REALTIME-derived deadline. This means any client can hold the server in grace indefinitely by sending CLAIM_PREVIOUS OPEN requests, blocking all non-reclaim operations for all other clients. Add boot_time_bt (CLOCK_BOOTTIME) alongside the existing boot_time and use it for the deadline computation. boot_time (CLOCK_REALTIME) is preserved for its cl_boot clientid-nonce role. Fixes: 20b7d86f29d3 ("nfsd: use boottime for lease expiry calculation") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20260611-nfsd-testing-v2-12-5b90e276f2d9@kernel.org Signed-off-by: Chuck Lever [ preserved the branch’s boolean fields instead of the upstream flags bitmap ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/netns.h | 1 + fs/nfsd/nfs4state.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) --- a/fs/nfsd/netns.h +++ b/fs/nfsd/netns.h @@ -69,6 +69,7 @@ struct nfsd_net { bool grace_end_forced; bool client_tracking_active; time64_t boot_time; + time64_t boot_time_bt; /* same instant in CLOCK_BOOTTIME */ struct dentry *nfsd_client_dir; --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -6769,7 +6769,7 @@ bool nfsd4_force_end_grace(struct nfsd_n */ static bool clients_still_reclaiming(struct nfsd_net *nn) { - time64_t double_grace_period_end = nn->boot_time + + time64_t double_grace_period_end = nn->boot_time_bt + 2 * nn->nfsd4_lease; if (READ_ONCE(nn->grace_end_forced)) @@ -9120,6 +9120,7 @@ static int nfs4_state_create_net(struct nn->conf_name_tree = RB_ROOT; nn->unconf_name_tree = RB_ROOT; nn->boot_time = ktime_get_real_seconds(); + nn->boot_time_bt = ktime_get_boottime_seconds(); nn->grace_ended = false; nn->grace_end_forced = false; nn->client_tracking_active = false;