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-rw-r--r--net/sunrpc/cache.c32
1 files changed, 16 insertions, 16 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index c536cc24b3d1..cdda4744c9b1 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1450,8 +1450,8 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
struct cache_detail *cd)
{
char tbuf[20];
- char *bp, *ep;
- time_t then, now;
+ char *ep;
+ time_t now;
if (*ppos || count > sizeof(tbuf)-1)
return -EINVAL;
@@ -1461,24 +1461,24 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
simple_strtoul(tbuf, &ep, 0);
if (*ep && *ep != '\n')
return -EINVAL;
+ /* Note that while we check that 'buf' holds a valid number,
+ * we always ignore the value and just flush everything.
+ * Making use of the number leads to races.
+ */
- bp = tbuf;
- then = get_expiry(&bp);
now = seconds_since_boot();
- cd->nextcheck = now;
- /* Can only set flush_time to 1 second beyond "now", or
- * possibly 1 second beyond flushtime. This is because
- * flush_time never goes backwards so it mustn't get too far
- * ahead of time.
+ /* Always flush everything, so behave like cache_purge()
+ * Do this by advancing flush_time to the current time,
+ * or by one second if it has already reached the current time.
+ * Newly added cache entries will always have ->last_refresh greater
+ * that ->flush_time, so they don't get flushed prematurely.
*/
- if (then >= now) {
- /* Want to flush everything, so behave like cache_purge() */
- if (cd->flush_time >= now)
- now = cd->flush_time + 1;
- then = now;
- }
- cd->flush_time = then;
+ if (cd->flush_time >= now)
+ now = cd->flush_time + 1;
+
+ cd->flush_time = now;
+ cd->nextcheck = now;
cache_flush();
*ppos += count;