libnvdimm, btt: write and validate parent_uuid

When a BTT is instantiated on a namespace it must validate the namespace
uuid matches the 'parent_uuid' stored in the btt superblock. This
property enforces that changing the namespace UUID invalidates all
former BTT instances on that storage. For "IO namespaces" that don't
have a label or UUID, the parent_uuid is set to zero, and this
validation is skipped. For such cases, old BTTs have to be invalidated
by forcing the namespace to raw mode, and overwriting the BTT info
blocks.

Based on a patch by Dan Williams <dan.j.williams@intel.com>

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 6567746aa315edda1f2e00b450ca59b31266f9b5..19588291550b5474432d2f8b9c0f9a0949095b8e 100644 (file)
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -733,6 +733,7 @@ static int btt_arena_write_layout(struct arena_info *arena)
        int ret;
        struct btt_sb *super;
        struct nd_btt *nd_btt = arena->nd_btt;
+       const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
 
        ret = btt_map_init(arena);
        if (ret)
@@ -748,6 +749,7 @@ static int btt_arena_write_layout(struct arena_info *arena)
 
        strncpy(super->signature, BTT_SIG, BTT_SIG_LEN);
        memcpy(super->uuid, nd_btt->uuid, 16);
+       memcpy(super->parent_uuid, parent_uuid, 16);
        super->flags = cpu_to_le32(arena->flags);
        super->version_major = cpu_to_le16(arena->version_major);
        super->version_minor = cpu_to_le16(arena->version_minor);

diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
index 18e0663e922c1c1af71ca82e1a07db67177b009d..242ae1c550ad6f87137fd1838a46b00fd3b5e22f 100644 (file)
--- a/drivers/nvdimm/btt_devs.c
+++ b/drivers/nvdimm/btt_devs.c
@@ -342,24 +342,37 @@ struct device *nd_btt_create(struct nd_region *nd_region)
        return dev;
 }
 
+static bool uuid_is_null(u8 *uuid)
+{
+       static const u8 null_uuid[16];
+
+       return (memcmp(uuid, null_uuid, 16) == 0);
+}
+
 /**
  * nd_btt_arena_is_valid - check if the metadata layout is valid
  * @nd_btt:    device with BTT geometry and backing device info
  * @super:     pointer to the arena's info block being tested
  *
  * Check consistency of the btt info block with itself by validating
- * the checksum.
+ * the checksum, and with the parent namespace by verifying the
+ * parent_uuid contained in the info block with the one supplied in.
  *
  * Returns:
  * false for an invalid info block, true for a valid one
  */
 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)
 {
+       const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
        u64 checksum;
 
        if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0)
                return false;
 
+       if (!uuid_is_null(super->parent_uuid))
+               if (memcmp(super->parent_uuid, parent_uuid, 16) != 0)
+                       return false;
+
        checksum = le64_to_cpu(super->checksum);
        super->checksum = 0;
        if (checksum != nd_btt_sb_checksum(super))

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index fef0dd80d4adb18c10a62a89ae0a53a78c9ea091..b18ffea9d85be34558318bab8f1eee036f0ad725 100644 (file)
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -100,6 +100,26 @@ const char *nvdimm_namespace_disk_name(struct nd_namespace_common *ndns,
 }
 EXPORT_SYMBOL(nvdimm_namespace_disk_name);
 
+const u8 *nd_dev_to_uuid(struct device *dev)
+{
+       static const u8 null_uuid[16];
+
+       if (!dev)
+               return null_uuid;
+
+       if (is_namespace_pmem(dev)) {
+               struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
+
+               return nspm->uuid;
+       } else if (is_namespace_blk(dev)) {
+               struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
+
+               return nsblk->uuid;
+       } else
+               return null_uuid;
+}
+EXPORT_SYMBOL(nd_dev_to_uuid);
+
 static ssize_t nstype_show(struct device *dev,
                struct device_attribute *attr, char *buf)
 {

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index 835263e47bb87d69cbe4be38bdb2fcac3ee69e7c..f9615824947bd7e0516ca827867190ae65f0488d 100644 (file)
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -217,4 +217,5 @@ static inline bool nd_iostat_start(struct bio *bio, unsigned long *start)
 }
 void nd_iostat_end(struct bio *bio, unsigned long start);
 resource_size_t nd_namespace_blk_validate(struct nd_namespace_blk *nsblk);
+const u8 *nd_dev_to_uuid(struct device *dev);
 #endif /* __ND_H__ */