[PATCH 5.5 299/367] nfsd: fix jiffies/time_t mixup in LRU list

Greg Kroah-Hartman
2020-02-10T12:48:48Z

From: Arnd Bergmann <arnd@arndb.de>

commit 9594497f2c78993cb66b696122f7c65528ace985 upstream.

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@arndb.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfsd/nfs4state.c | 2 +-
fs/nfsd/state.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6550,7 +6550,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struc
}

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);
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -606,7 +606,7 @@ static inline bool nfsd4_stateid_generat
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;