@@ -20,6 +20,12 @@
#define PFN_SIG_LEN 16
#define PFN_SIG "NVDIMM_PFN_INFO\0"
#define DAX_SIG "NVDIMM_DAX_INFO\0"
+/*
+ * increment this when we are making changes such that older
+ * kernel should fail to initialize that namespace.
+ */
+
+#define PFN_MIN_VERSION 0
struct nd_pfn_sb {
u8 signature[PFN_SIG_LEN];
@@ -36,7 +42,8 @@ struct nd_pfn_sb {
__le32 end_trunc;
/* minor-version-2 record the base alignment of the mapping */
__le32 align;
- u8 padding[4000];
+ __le16 min_version;
+ u8 padding[3998];
__le64 checksum;
};
@@ -439,6 +439,14 @@ int nd_pfn_validate(struct nd_pfn *nd_pfn, const char *sig)
if (nvdimm_read_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb), 0))
return -ENXIO;
+ if (le16_to_cpu(pfn_sb->min_version) > PFN_MIN_VERSION) {
+ dev_err(&nd_pfn->dev,
+ "init failed, superblock min version %d kernel"
+ " support version %d\n",
+ le16_to_cpu(pfn_sb->min_version), PFN_MIN_VERSION);
+ return -EOPNOTSUPP;
+ }
+
if (memcmp(pfn_sb->signature, sig, PFN_SIG_LEN) != 0)
return -ENODEV;
@@ -769,6 +777,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
memcpy(pfn_sb->parent_uuid, nd_dev_to_uuid(&ndns->dev), 16);
pfn_sb->version_major = cpu_to_le16(1);
pfn_sb->version_minor = cpu_to_le16(2);
+ pfn_sb->min_version = cpu_to_le16(PFN_MIN_VERSION);
pfn_sb->start_pad = cpu_to_le32(start_pad);
pfn_sb->end_trunc = cpu_to_le32(end_trunc);
pfn_sb->align = cpu_to_le32(nd_pfn->align);
@@ -496,6 +496,7 @@ static int pmem_attach_disk(struct device *dev,
static int nd_pmem_probe(struct device *dev)
{
+ int ret;
struct nd_namespace_common *ndns;
ndns = nvdimm_namespace_common_probe(dev);
@@ -511,12 +512,29 @@ static int nd_pmem_probe(struct device *dev)
if (is_nd_pfn(dev))
return pmem_attach_disk(dev, ndns);
- /* if we find a valid info-block we'll come back as that personality */
- if (nd_btt_probe(dev, ndns) == 0 || nd_pfn_probe(dev, ndns) == 0
- || nd_dax_probe(dev, ndns) == 0)
+ ret = nd_btt_probe(dev, ndns);
+ if (ret == 0)
return -ENXIO;
+ else if (ret == -EOPNOTSUPP)
+ return ret;
- /* ...otherwise we're just a raw pmem device */
+ ret = nd_pfn_probe(dev, ndns);
+ if (ret == 0)
+ return -ENXIO;
+ else if (ret == -EOPNOTSUPP)
+ return ret;
+
+ ret = nd_dax_probe(dev, ndns);
+ if (ret == 0)
+ return -ENXIO;
+ else if (ret == -EOPNOTSUPP)
+ return ret;
+ /*
+ * We have two failure conditions here, there is no
+ * info reserver block or we found a valid info reserve block
+ * but failed to initialize the pfn superblock.
+ * Don't create a raw pmem disk for the second case.
+ */
return pmem_attach_disk(dev, ndns);
}
This allows us to make changes in a backward incompatible way. I have kept the PFN_MIN_VERSION in this patch '0' because we are not introducing any incompatible changes in this patch. We also may want to backport this to older kernels. The error looks like dax0.1: init failed, superblock min version 1, kernel support version 0 and the namespace is marked disabled $ndctl list -Ni [ { "dev":"namespace0.0", "mode":"fsdax", "map":"mem", "size":10737418240, "uuid":"9605de6d-cefa-4a87-99cd-dec28b02cffe", "state":"disabled" } ] Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- drivers/nvdimm/pfn.h | 9 ++++++++- drivers/nvdimm/pfn_devs.c | 9 +++++++++ drivers/nvdimm/pmem.c | 26 ++++++++++++++++++++++---- 3 files changed, 39 insertions(+), 5 deletions(-)