rbd: set mapping read-only flag in rbd_add()

The rbd_dev->mapping field for a parent image is not meaningful.
Since rbd_image_probe() is used both for images being mapped and
their parents, it doesn't make sense to set that flag in that
function.

So move the setting of the mapping.read_only flag out of
rbd_dev_image_probe() and into rbd_add() instead.

This resolves:
    http://tracker.ceph.com/issues/4940

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 11 insertions, 12 deletions

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 2a0e9b81be48..dbfc44a9defd 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -358,7 +358,7 @@ static ssize_t rbd_add(struct bus_type *bus, const char *buf,
                        size_t count);
 static ssize_t rbd_remove(struct bus_type *bus, const char *buf,
                           size_t count);
-static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool read_only);
+static int rbd_dev_image_probe(struct rbd_device *rbd_dev);
 
 static struct bus_attribute rbd_bus_attrs[] = {
         __ATTR(add, S_IWUSR, NULL, rbd_add),
@@ -4549,7 +4549,7 @@ static int rbd_dev_probe_parent(struct rbd_device *rbd_dev)
         if (!parent)
                 goto out_err;
 
-        ret = rbd_dev_image_probe(parent, true);
+        ret = rbd_dev_image_probe(parent);
         if (ret < 0)
                 goto out_err;
         rbd_dev->parent = parent;
@@ -4671,10 +4671,9 @@ static void rbd_dev_image_release(struct rbd_device *rbd_dev)
 
 /*
  * Probe for the existence of the header object for the given rbd
- * device.  For format 2 images this includes determining the image
- * id.
+ * device.
  */
-static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool read_only)
+static int rbd_dev_image_probe(struct rbd_device *rbd_dev)
 {
         int ret;
         int tmp;
@@ -4709,12 +4708,6 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev, bool read_only)
         if (ret)
                 goto err_out_probe;
 
-        /* If we are mapping a snapshot it must be marked read-only */
-
-        if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
-                read_only = true;
-        rbd_dev->mapping.read_only = read_only;
-
         ret = rbd_dev_probe_parent(rbd_dev);
         if (ret)
                 goto err_out_probe;
@@ -4795,10 +4788,16 @@ static ssize_t rbd_add(struct bus_type *bus,
         rbdc = NULL;            /* rbd_dev now owns this */
         spec = NULL;            /* rbd_dev now owns this */
 
-        rc = rbd_dev_image_probe(rbd_dev, read_only);
+        rc = rbd_dev_image_probe(rbd_dev);
         if (rc < 0)
                 goto err_out_rbd_dev;
 
+        /* If we are mapping a snapshot it must be marked read-only */
+
+        if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
+                read_only = true;
+        rbd_dev->mapping.read_only = read_only;
+
         rc = rbd_dev_device_setup(rbd_dev);
         if (!rc)
                 return count;