libceph: store timeouts in jiffies, verify user input

There are currently three libceph-level timeouts that the user can
specify on mount: mount_timeout, osd_idle_ttl and osdkeepalive.  All of
these are in seconds and no checking is done on user input: negative
values are accepted, we multiply them all by HZ which may or may not
overflow, arbitrarily large jiffies then get added together, etc.

There is also a bug in the way mount_timeout=0 is handled.  It's
supposed to mean "infinite timeout", but that's not how wait.h APIs
treat it and so __ceph_open_session() for example will busy loop
without much chance of being interrupted if none of ceph-mons are
there.

Fix all this by verifying user input, storing timeouts capped by
msecs_to_jiffies() in jiffies and using the new ceph_timeout_jiffies()
helper for all user-specified waits to handle infinite timeouts
correctly.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 349115ae3bc2..992683b6b299 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4963,8 +4963,8 @@ out_err:
  */
 static int rbd_add_get_pool_id(struct rbd_client *rbdc, const char *pool_name)
 {
+        struct ceph_options *opts = rbdc->client->options;
         u64 newest_epoch;
-        unsigned long timeout = rbdc->client->options->mount_timeout * HZ;
         int tries = 0;
         int ret;
 
@@ -4979,7 +4979,8 @@ again:
                 if (rbdc->client->osdc.osdmap->epoch < newest_epoch) {
                         ceph_monc_request_next_osdmap(&rbdc->client->monc);
                         (void) ceph_monc_wait_osdmap(&rbdc->client->monc,
-                                                     newest_epoch, timeout);
+                                                     newest_epoch,
+                                                     opts->mount_timeout);
                         goto again;
                 } else {
                         /* the osdmap we have is new enough */