[Devel] [PATCH RHEL7 COMMIT] ms/nfsd: fix jiffies/time_t mixup in LRU list

[Vasily Averin]

The commit is pushed to "branch-rh7-3.10.0-1160.42.2.vz7.184.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.42.2.vz7.184.4
------>
commit 0f59eeb6878eba2ccda78d8e98261aa4b7213e76
Author: Vasily Averin <vvs at virtuozzo.com>
Date:   Wed Nov 24 14:49:57 2021 +0300

    ms/nfsd: fix jiffies/time_t mixup in LRU list
    
    The nfsd4_blocked_lock->nbl_time timestamp is recorded in jiffies,
    but then compared to a CLOCK_REALTIME timestamp later on, which makes
    no sense.
    
    For consistency with the other timestamps, change this to use a time_t.
    
    This is a change in behavior, which may cause regressions, but the
    current code is not sensible. On a system with CONFIG_HZ=1000,
    the 'time_after((unsigned long)nbl->nbl_time, (unsigned long)cutoff))'
    check is false for roughly the first 18 days of uptime and then true
    for the next 49 days.
    
    Fixes: 7919d0a27f1e ("nfsd: add a LRU list for blocked locks")
    Signed-off-by: Arnd Bergmann <arnd at arndb.de>
    Signed-off-by: J. Bruce Fields <bfields at redhat.com>
    
    (cherry picked from commit 9594497f2c78993cb66b696122f7c65528ace985)
    https://jira.sw.ru/browse/PSBM-102407
    https://jira.sw.ru/browse/PSBM-121875
    https://jira.sw.ru/browse/PSBM-121984
    https://jira.sw.ru/browse/PSBM-129208
    https://jira.sw.ru/browse/PSBM-129647
    https://jira.sw.ru/browse/PSBM-133020
    https://jira.sw.ru/browse/PSBM-133265
    https://jira.sw.ru/browse/PSBM-133274
    https://jira.sw.ru/browse/PSBM-134762
    https://jira.sw.ru/browse/PSBM-134877
    https://jira.sw.ru/browse/PSBM-134905
    https://jira.sw.ru/browse/PSBM-135845
    Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
---
 fs/nfsd/nfs4state.c | 2 +-
 fs/nfsd/state.h     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 07e9681..4a57b40 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5991,7 +5991,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	}
 
 	if (fl_flags & FL_SLEEP) {
-		nbl->nbl_time = jiffies;
+		nbl->nbl_time = get_seconds();
 		spin_lock(&nn->blocked_locks_lock);
 		list_add_tail(&nbl->nbl_list, &lock_sop->lo_blocked);
 		list_add_tail(&nbl->nbl_lru, &nn->blocked_locks_lru);
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 770b1c6..f53db66 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -583,7 +583,7 @@ enum nfsd4_cb_op {
 struct nfsd4_blocked_lock {
 	struct list_head	nbl_list;
 	struct list_head	nbl_lru;
-	unsigned long		nbl_time;
+	time_t			nbl_time;
 	struct file_lock	nbl_lock;
 	struct knfsd_fh		nbl_fh;
 	struct nfsd4_callback	nbl_cb;