FAILED: patch "[PATCH] nfsd: fix clock domain mismatch in clients_still_reclaiming()" failed to apply to 6.1-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 09ea3eb9a518565f5bca386e81b993ed8825f5e8
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090315-napping-explicit-71f2@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 09ea3eb9a518565f5bca386e81b993ed8825f5e8 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton@kernel.org>
Date: Thu, 11 Jun 2026 16:00:55 -0400
Subject: [PATCH] nfsd: fix clock domain mismatch in clients_still_reclaiming()
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

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 <jlayton@kernel.org>
Link: https://patch.msgid.link/20260611-nfsd-testing-v2-12-5b90e276f2d9@kernel.org
Signed-off-by: Chuck Lever <cel@kernel.org>

diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index 5c33c96da28e..03724bef10a7 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -78,6 +78,7 @@ struct nfsd_net {
 	struct lock_manager nfsd4_manager;
 	unsigned long flags;
 	time64_t boot_time;
+	time64_t boot_time_bt;	/* same instant in CLOCK_BOOTTIME */
 
 	struct dentry *nfsd_client_dir;
 
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 3dc0c0f6eb5d..17cb3b0ad956 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6870,7 +6870,7 @@ bool nfsd4_force_end_grace(struct nfsd_net *nn)
  */
 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 (test_bit(NFSD_NET_GRACE_END_FORCED, &nn->flags))
@@ -9245,6 +9245,7 @@ static int nfs4_state_create_net(struct net *net)
 	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();
 	clear_bit(NFSD_NET_GRACE_ENDED, &nn->flags);
 	clear_bit(NFSD_NET_GRACE_END_FORCED, &nn->flags);
 	nn->nfsd4_manager.block_opens = true;