rbd: add warnings to rbd_dev_probe_update_spec()

Josh suggested adding warnings to this function to help users
diagnose problems.

Other than memory allocatino errors, there are two places where
errors can be returned.  Both represent problems that should
have been caught earlier, and as such might well have been
handled with BUG_ON() calls.  But if either ever did manage to
happen, it will be reported.

Signed-off-by: Alex Elder <elder@inktank.com>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 3ab39705301036af9970c1679f90cefaca989f97..5de49a1c62fe1e775491dc9d0b6a737cc9f2530c 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2646,8 +2646,11 @@ static int rbd_dev_probe_update_spec(struct rbd_device *rbd_dev)
 
        osdc = &rbd_dev->rbd_client->client->osdc;
        name = ceph_pg_pool_name_by_id(osdc->osdmap, rbd_dev->spec->pool_id);
-       if (!name)
-               return -EIO;    /* pool id too large (>= 2^31) */
+       if (!name) {
+               rbd_warn(rbd_dev, "there is no pool with id %llu",
+                       rbd_dev->spec->pool_id);        /* Really a BUG() */
+               return -EIO;
+       }
 
        rbd_dev->spec->pool_name = kstrdup(name, GFP_KERNEL);
        if (!rbd_dev->spec->pool_name)
@@ -2665,6 +2668,8 @@ static int rbd_dev_probe_update_spec(struct rbd_device *rbd_dev)
 
        name = rbd_snap_name(rbd_dev, rbd_dev->spec->snap_id);
        if (!name) {
+               rbd_warn(rbd_dev, "no snapshot with id %llu",
+                       rbd_dev->spec->snap_id);        /* Really a BUG() */
                ret = -EIO;
                goto out_err;
        }