4.4-stable review patch. If anyone has any objections, please let me know.
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From: Dan Williams dan.j.williams@intel.com
commit b18d4b8a25af6fe83d7692191d6ff962ea611c4f upstream.
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: f524bf271a5c ("libnvdimm: write pmem label set") Reported-by: Juston Li juston.li@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/nvdimm/label.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/nvdimm/label.c +++ b/drivers/nvdimm/label.c @@ -823,7 +823,7 @@ static int init_labels(struct nd_mapping 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;