this protects us from confusion when the wallclock time changes.
We convert to and from wallclock when setting or reading expiry
times.
Also use monotonic_seconds for last_clost time.
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
fs/nfs/dns_resolve.c | 6 +++---
fs/nfsd/nfs4idmap.c | 2 +-
include/linux/sunrpc/cache.h | 21 ++++++++++++++++++---
net/sunrpc/cache.c | 37 ++++++++++++++++++++-----------------
4 files changed, 42 insertions(+), 24 deletions(-)
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 76fd235..3e6aab2 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -144,7 +144,7 @@ static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
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 - monotonic_seconds();
if (ttl < 0)
ttl = 0;
@@ -216,7 +216,7 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
ttl = get_expiry(&buf);
if (ttl == 0)
goto out;
- key.h.expiry_time = ttl + get_seconds();
+ key.h.expiry_time = ttl + monotonic_seconds();
ret = -ENOMEM;
item = nfs_dns_lookup(cd, &key);
@@ -278,7 +278,7 @@ static int do_cache_lookup_nowait(struct cache_detail *cd,
goto out_err;
ret = -ETIMEDOUT;
if (!test_bit(CACHE_VALID, &(*item)->h.flags)
- || (*item)->h.expiry_time < get_seconds()
+ || (*item)->h.expiry_time < monotonic_seconds()
|| 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..6031a90 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -550,7 +550,7 @@ do_idmap_lookup_nowait(struct ent *(*lookup_fn)(struct ent *),
goto out_err;
ret = -ETIMEDOUT;
if (!test_bit(CACHE_VALID, &(*item)->h.flags)
- || (*item)->h.expiry_time < get_seconds()
+ || (*item)->h.expiry_time < monotonic_seconds()
|| 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..df7c19b 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -218,20 +218,35 @@ static inline int get_int(char **bpp, int *anint)
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 monotonic_seconds(void)
+{
+ struct timespec boot;
+ getboottime(&boot);
+ return get_seconds() - boot.tv_sec;
+}
+
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 = monotonic_seconds() - 1;
+ detail->nextcheck = monotonic_seconds();
}
#endif /* _LINUX_SUNRPC_CACHE_H_ */
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 2b06410..99d852e 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -42,7 +42,7 @@ static void cache_revisit_request(struct cache_head *item);
static void cache_init(struct cache_head *h)
{
- time_t now = get_seconds();
+ time_t now = monotonic_seconds();
h->next = NULL;
h->flags = 0;
kref_init(&h->ref);
@@ -52,7 +52,7 @@ static void cache_init(struct cache_head *h)
static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
{
- return (h->expiry_time < get_seconds()) ||
+ return (h->expiry_time < monotonic_seconds()) ||
(detail->flush_time > h->last_refresh);
}
@@ -127,7 +127,7 @@ static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
static void cache_fresh_locked(struct cache_head *head, time_t expiry)
{
head->expiry_time = expiry;
- head->last_refresh = get_seconds();
+ head->last_refresh = monotonic_seconds();
set_bit(CACHE_VALID, &head->flags);
}
@@ -238,7 +238,7 @@ int cache_check(struct cache_detail *detail,
/* now see if we want to start an upcall */
refresh_age = (h->expiry_time - h->last_refresh);
- age = get_seconds() - h->last_refresh;
+ age = monotonic_seconds() - h->last_refresh;
if (rqstp == NULL) {
if (rv == -EAGAIN)
@@ -253,7 +253,7 @@ int cache_check(struct cache_detail *detail,
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, monotonic_seconds()+CACHE_NEW_EXPIRY);
cache_fresh_unlocked(h, detail);
rv = -ENOENT;
}
@@ -388,11 +388,11 @@ static int cache_clean(void)
return -1;
}
current_detail = list_entry(next, struct cache_detail, others);
- if (current_detail->nextcheck > get_seconds())
+ if (current_detail->nextcheck > monotonic_seconds())
current_index = current_detail->hash_size;
else {
current_index = 0;
- current_detail->nextcheck = get_seconds()+30*60;
+ current_detail->nextcheck = monotonic_seconds()+30*60;
}
}
@@ -477,7 +477,7 @@ EXPORT_SYMBOL_GPL(cache_flush);
void cache_purge(struct cache_detail *detail)
{
detail->flush_time = LONG_MAX;
- detail->nextcheck = get_seconds();
+ detail->nextcheck = monotonic_seconds();
cache_flush();
detail->flush_time = 1;
}
@@ -902,7 +902,7 @@ static int cache_release(struct inode *inode, struct file *filp,
filp->private_data = NULL;
kfree(rp);
- cd->last_close = get_seconds();
+ cd->last_close = monotonic_seconds();
atomic_dec(&cd->readers);
}
module_put(cd->owner);
@@ -1034,7 +1034,7 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h,
int len;
if (atomic_read(&detail->readers) == 0 &&
- detail->last_close < get_seconds() - 30) {
+ detail->last_close < monotonic_seconds() - 30) {
warn_no_listener(detail);
return -EINVAL;
}
@@ -1219,7 +1219,8 @@ static int c_show(struct seq_file *m, void *p)
ifdebug(CACHE)
seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
- cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags);
+ cp->expiry_time - monotonic_seconds() + get_seconds(),
+ 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 +1286,8 @@ static ssize_t read_flush(struct file *file, char __user *buf,
unsigned long p = *ppos;
size_t len;
- sprintf(tbuf, "%lu\n", cd->flush_time);
+ sprintf(tbuf, "%lu\n", (cd->flush_time - monotonic_seconds()
+ + get_seconds()));
len = strlen(tbuf);
if (p >= len)
return 0;
@@ -1303,19 +1305,20 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
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 = monotonic_seconds();
cache_flush();
*ppos += count;
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
