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authorArnd Bergmann <arnd@arndb.de>2019-11-04 16:31:52 +0100
committerJ. Bruce Fields <bfields@redhat.com>2019-12-20 04:07:17 +0100
commit20b7d86f29d39e8ae19bb29c24ffee70dc385ddf (patch)
treef364c2f6a1a9fed9a9bc8cdc0673381e29cf596b /fs/nfsd/nfs4callback.c
parentnfsd: fix jiffies/time_t mixup in LRU list (diff)
downloadlinux-20b7d86f29d39e8ae19bb29c24ffee70dc385ddf.tar.xz
linux-20b7d86f29d39e8ae19bb29c24ffee70dc385ddf.zip
nfsd: use boottime for lease expiry calculation
A couple of time_t variables are only used to track the state of the lease time and its expiration. The code correctly uses the 'time_after()' macro to make this work on 32-bit architectures even beyond year 2038, but the get_seconds() function and the time_t type itself are deprecated as they behave inconsistently between 32-bit and 64-bit architectures and often lead to code that is not y2038 safe. As a minor issue, using get_seconds() leads to problems with concurrent settimeofday() or clock_settime() calls, in the worst case timeout never triggering after the time has been set backwards. Change nfsd to use time64_t and ktime_get_boottime_seconds() here. This is clearly excessive, as boottime by itself means we never go beyond 32 bits, but it does mean we handle this correctly and consistently without having to worry about corner cases and should be no more expensive than the previous implementation on 64-bit architectures. The max_cb_time() function gets changed in order to avoid an expensive 64-bit division operation, but as the lease time is at most one hour, there is no change in behavior. Also do the same for server-to-server copy expiration time. Signed-off-by: Arnd Bergmann <arnd@arndb.de> [bfields@redhat.com: fix up copy expiration] Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd/nfs4callback.c')
-rw-r--r--fs/nfsd/nfs4callback.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 24534db87e86..c3b11a715082 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -823,7 +823,16 @@ static const struct rpc_program cb_program = {
static int max_cb_time(struct net *net)
{
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
- return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
+
+ /*
+ * nfsd4_lease is set to at most one hour in __nfsd4_write_time,
+ * so we can use 32-bit math on it. Warn if that assumption
+ * ever stops being true.
+ */
+ if (WARN_ON_ONCE(nn->nfsd4_lease > 3600))
+ return 360 * HZ;
+
+ return max(((u32)nn->nfsd4_lease)/10, 1u) * HZ;
}
static struct workqueue_struct *callback_wq;