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nfsd: fix clock domain mismatch in clients_still_reclaiming()

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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: 20b7d86f29 ("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>
This commit is contained in:
Jeff Layton
2026-06-11 16:00:55 -04:00
committed by Chuck Lever
parent 4e475be769
commit 09ea3eb9a5
2 changed files with 3 additions and 1 deletions
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1
fs/nfsd/netns.h
View File

@@ -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;

3
fs/nfsd/nfs4state.c
View File

@@ -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;