Commit b18d4b8a authored Sep 26, 2017 by Dan Williams

libnvdimm, namespace: fix label initialization to use valid seq numbers



The set of valid sequence numbers is {1,2,3}. The specification
indicates that an implementation should consider 0 a sign of a critical
error:

    UEFI 2.7: 13.19 NVDIMM Label Protocol

    Software never writes the sequence number 00, so a correctly
    check-summed Index Block with this sequence number probably indicates a
    critical error. When software discovers this case it treats it as an
    invalid Index Block indication.

While the expectation is that the invalid block is just thrown away, the
Robustness Principle says we should fix this to make both sequence
numbers valid.

Fixes: f524bf27 ("libnvdimm: write pmem label set")
Cc: <stable@vger.kernel.org>
Reported-by: Juston Li <juston.li@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

parent 26417ae4

drivers/nvdimm/label.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1050,7 +1050,7 @@ static int init_labels(struct nd_mapping *nd_mapping, int num_labels)
		nsindex = to_namespace_index(ndd, 0);
		memset(nsindex, 0, ndd->nsarea.config_size);
		for (i = 0; i < 2; i++) {
		int rc = nd_label_write_index(ndd, i, i*2, ND_NSINDEX_INIT);
		int rc = nd_label_write_index(ndd, i, 3 - i, ND_NSINDEX_INIT);

		if (rc)
		return rc;