rbd: make sure we have latest osdmap on 'rbd map'

Given an existing idle mapping (img1), mapping an image (img2) in
a newly created pool (pool2) fails:

    $ ceph osd pool create pool1 8 8
    $ rbd create --size 1000 pool1/img1
    $ sudo rbd map pool1/img1
    $ ceph osd pool create pool2 8 8
    $ rbd create --size 1000 pool2/img2
    $ sudo rbd map pool2/img2
    rbd: sysfs write failed
    rbd: map failed: (2) No such file or directory

This is because client instances are shared by default and we don't
request an osdmap update when bumping a ref on an existing client.  The
fix is to use the mon_get_version request to see if the osdmap we have
is the latest, and block until the requested update is received if it's
not.

Fixes: http://tracker.ceph.com/issues/8184

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 552a2edcaa7417d621176b8ad182fdd25af1b953..daf7b4659b4a201836b10d8243614a311ecfc285 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4682,6 +4682,38 @@ out_err:
        return ret;
 }
 
+/*
+ * Return pool id (>= 0) or a negative error code.
+ */
+static int rbd_add_get_pool_id(struct rbd_client *rbdc, const char *pool_name)
+{
+       u64 newest_epoch;
+       unsigned long timeout = rbdc->client->options->mount_timeout * HZ;
+       int tries = 0;
+       int ret;
+
+again:
+       ret = ceph_pg_poolid_by_name(rbdc->client->osdc.osdmap, pool_name);
+       if (ret == -ENOENT && tries++ < 1) {
+               ret = ceph_monc_do_get_version(&rbdc->client->monc, "osdmap",
+                                              &newest_epoch);
+               if (ret < 0)
+                       return ret;
+
+               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);
+                       goto again;
+               } else {
+                       /* the osdmap we have is new enough */
+                       return -ENOENT;
+               }
+       }
+
+       return ret;
+}
+
 /*
  * An rbd format 2 image has a unique identifier, distinct from the
  * name given to it by the user.  Internally, that identifier is
@@ -5053,7 +5085,6 @@ static ssize_t do_rbd_add(struct bus_type *bus,
        struct rbd_options *rbd_opts = NULL;
        struct rbd_spec *spec = NULL;
        struct rbd_client *rbdc;
-       struct ceph_osd_client *osdc;
        bool read_only;
        int rc = -ENOMEM;
 
@@ -5075,8 +5106,7 @@ static ssize_t do_rbd_add(struct bus_type *bus,
        }
 
        /* pick the pool */
-       osdc = &rbdc->client->osdc;
-       rc = ceph_pg_poolid_by_name(osdc->osdmap, spec->pool_name);
+       rc = rbd_add_get_pool_id(rbdc, spec->pool_name);
        if (rc < 0)
                goto err_out_client;
        spec->pool_id = (u64)rc;