[ndctl] ndctl/namespace: Fix destroy-namespace accounting relative to seed devices

Commit Message

Dan Williams Jan. 9, 2020, 4:17 a.m. UTC

Seed namespaces are included in "ndctl destroy-namespace all". However
since the user never "creates" them it is surprising to see
"destroy-namespace" report 1 more namespace relative to the number that
have been created. Catch attempts to destroy a zero-sized namespace:

Before:
# ndctl create-namespace -s 500M
{
  "dev":"namespace1.0",
  "size":"492.00 MiB (515.90 MB)",
  "blockdev":"pmem1"
}
# ndctl create-namespace -s 500M
{
  "dev":"namespace1.1",
  "size":"492.00 MiB (515.90 MB)",
  "blockdev":"pmem1.1"
}
# ndctl create-namespace -s 500M
{
  "dev":"namespace1.2",
  "size":"492.00 MiB (515.90 MB)",
  "blockdev":"pmem1.2"
}
# ndctl destroy-namespace -r 1 all -f
destroyed 4 namespaces

After:
# ndctl create-namespace -s 500M
{
  "dev":"namespace1.0",
  "size":"492.00 MiB (515.90 MB)",
  "blockdev":"pmem1"
}
# ndctl create-namespace -s 500M
{
  "dev":"namespace1.3",
  "size":"492.00 MiB (515.90 MB)",
  "blockdev":"pmem1.3"
}
# ndctl create-namespace -s 500M
{
  "dev":"namespace1.1",
  "size":"492.00 MiB (515.90 MB)",
  "blockdev":"pmem1.1"
}
# ndctl destroy-namespace -r 1 all -f
destroyed 3 namespaces

Signed-off-by: Dan Williams <[e-mail]>
---
 ndctl/namespace.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

Patch

diff --git a/ndctl/namespace.c b/ndctl/namespace.c
index 2f463509f8ca..994b4e8791ea 100644
--- a/ndctl/namespace.c
+++ b/ndctl/namespace.c
@@ -907,6 +907,7 @@  static int namespace_destroy(struct ndctl_region *region,
 	struct ndctl_pfn *pfn = ndctl_namespace_get_pfn(ndns);
 	struct ndctl_dax *dax = ndctl_namespace_get_dax(ndns);
 	struct ndctl_btt *btt = ndctl_namespace_get_btt(ndns);
+	unsigned long long size;
 	bool did_zero = false;
 	int rc;
 
@@ -953,10 +954,19 @@  static int namespace_destroy(struct ndctl_region *region,
 		goto out;
 	}
 
+	size = ndctl_namespace_get_size(ndns);
+
 	rc = ndctl_namespace_delete(ndns);
 	if (rc)
 		debug("%s: failed to reclaim\n", devname);
 
+	/*
+	 * Don't report a destroyed namespace when no capacity was
+	 * allocated.
+	 */
+	if (size == 0 && rc == 0)
+		rc = 1;
+
 out:
 	return rc;
 }