sunrpc: use seconds since boot in expiry cache
This protects us from confusion when the wallclock time changes.
We convert to and from wallclock when setting or reading expiry
times.
Also use seconds since boot for last_clost time.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index dba50a5..a6e711a 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -167,7 +167,7 @@
return 0;
}
item = container_of(h, struct nfs_dns_ent, h);
- ttl = (long)item->h.expiry_time - (long)get_seconds();
+ ttl = item->h.expiry_time - seconds_since_boot();
if (ttl < 0)
ttl = 0;
@@ -239,7 +239,7 @@
ttl = get_expiry(&buf);
if (ttl == 0)
goto out;
- key.h.expiry_time = ttl + get_seconds();
+ key.h.expiry_time = ttl + seconds_since_boot();
ret = -ENOMEM;
item = nfs_dns_lookup(cd, &key);
@@ -301,7 +301,7 @@
goto out_err;
ret = -ETIMEDOUT;
if (!test_bit(CACHE_VALID, &(*item)->h.flags)
- || (*item)->h.expiry_time < get_seconds()
+ || (*item)->h.expiry_time < seconds_since_boot()
|| cd->flush_time > (*item)->h.last_refresh)
goto out_put;
ret = -ENOENT;
diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index c78dbf4..808b33a4 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -550,7 +550,7 @@
goto out_err;
ret = -ETIMEDOUT;
if (!test_bit(CACHE_VALID, &(*item)->h.flags)
- || (*item)->h.expiry_time < get_seconds()
+ || (*item)->h.expiry_time < seconds_since_boot()
|| detail->flush_time > (*item)->h.last_refresh)
goto out_put;
ret = -ENOENT;
diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 0e1febf..ece432b 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -218,20 +218,42 @@
return 0;
}
+/*
+ * timestamps kept in the cache are expressed in seconds
+ * since boot. This is the best for measuring differences in
+ * real time.
+ */
+static inline time_t seconds_since_boot(void)
+{
+ struct timespec boot;
+ getboottime(&boot);
+ return get_seconds() - boot.tv_sec;
+}
+
+static inline time_t convert_to_wallclock(time_t sinceboot)
+{
+ struct timespec boot;
+ getboottime(&boot);
+ return boot.tv_sec + sinceboot;
+}
+
static inline time_t get_expiry(char **bpp)
{
int rv;
+ struct timespec boot;
+
if (get_int(bpp, &rv))
return 0;
if (rv < 0)
return 0;
- return rv;
+ getboottime(&boot);
+ return rv - boot.tv_sec;
}
static inline void sunrpc_invalidate(struct cache_head *h,
struct cache_detail *detail)
{
- h->expiry_time = get_seconds() - 1;
- detail->nextcheck = get_seconds();
+ h->expiry_time = seconds_since_boot() - 1;
+ detail->nextcheck = seconds_since_boot();
}
#endif /* _LINUX_SUNRPC_CACHE_H_ */
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 2b06410..8dc1219 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -42,7 +42,7 @@
static void cache_init(struct cache_head *h)
{
- time_t now = get_seconds();
+ time_t now = seconds_since_boot();
h->next = NULL;
h->flags = 0;
kref_init(&h->ref);
@@ -52,7 +52,7 @@
static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
{
- return (h->expiry_time < get_seconds()) ||
+ return (h->expiry_time < seconds_since_boot()) ||
(detail->flush_time > h->last_refresh);
}
@@ -127,7 +127,7 @@
static void cache_fresh_locked(struct cache_head *head, time_t expiry)
{
head->expiry_time = expiry;
- head->last_refresh = get_seconds();
+ head->last_refresh = seconds_since_boot();
set_bit(CACHE_VALID, &head->flags);
}
@@ -238,7 +238,7 @@
/* now see if we want to start an upcall */
refresh_age = (h->expiry_time - h->last_refresh);
- age = get_seconds() - h->last_refresh;
+ age = seconds_since_boot() - h->last_refresh;
if (rqstp == NULL) {
if (rv == -EAGAIN)
@@ -253,7 +253,7 @@
cache_revisit_request(h);
if (rv == -EAGAIN) {
set_bit(CACHE_NEGATIVE, &h->flags);
- cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY);
+ cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
cache_fresh_unlocked(h, detail);
rv = -ENOENT;
}
@@ -388,11 +388,11 @@
return -1;
}
current_detail = list_entry(next, struct cache_detail, others);
- if (current_detail->nextcheck > get_seconds())
+ if (current_detail->nextcheck > seconds_since_boot())
current_index = current_detail->hash_size;
else {
current_index = 0;
- current_detail->nextcheck = get_seconds()+30*60;
+ current_detail->nextcheck = seconds_since_boot()+30*60;
}
}
@@ -477,7 +477,7 @@
void cache_purge(struct cache_detail *detail)
{
detail->flush_time = LONG_MAX;
- detail->nextcheck = get_seconds();
+ detail->nextcheck = seconds_since_boot();
cache_flush();
detail->flush_time = 1;
}
@@ -902,7 +902,7 @@
filp->private_data = NULL;
kfree(rp);
- cd->last_close = get_seconds();
+ cd->last_close = seconds_since_boot();
atomic_dec(&cd->readers);
}
module_put(cd->owner);
@@ -1034,7 +1034,7 @@
int len;
if (atomic_read(&detail->readers) == 0 &&
- detail->last_close < get_seconds() - 30) {
+ detail->last_close < seconds_since_boot() - 30) {
warn_no_listener(detail);
return -EINVAL;
}
@@ -1219,7 +1219,8 @@
ifdebug(CACHE)
seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
- cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
+ convert_to_wallclock(cp->expiry_time),
+ atomic_read(&cp->ref.refcount), cp->flags);
cache_get(cp);
if (cache_check(cd, cp, NULL))
/* cache_check does a cache_put on failure */
@@ -1285,7 +1286,7 @@
unsigned long p = *ppos;
size_t len;
- sprintf(tbuf, "%lu\n", cd->flush_time);
+ sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time));
len = strlen(tbuf);
if (p >= len)
return 0;
@@ -1303,19 +1304,20 @@
struct cache_detail *cd)
{
char tbuf[20];
- char *ep;
- long flushtime;
+ char *bp, *ep;
+
if (*ppos || count > sizeof(tbuf)-1)
return -EINVAL;
if (copy_from_user(tbuf, buf, count))
return -EFAULT;
tbuf[count] = 0;
- flushtime = simple_strtoul(tbuf, &ep, 0);
+ simple_strtoul(tbuf, &ep, 0);
if (*ep && *ep != '\n')
return -EINVAL;
- cd->flush_time = flushtime;
- cd->nextcheck = get_seconds();
+ bp = tbuf;
+ cd->flush_time = get_expiry(&bp);
+ cd->nextcheck = seconds_since_boot();
cache_flush();
*ppos += count;