[PATCH v4] libnvdimm: clear poison in mem map metadata

[Dave Jiang]

Clearing out the poison in the metadata block of the namespace before
we use it. Range from start + 8k to pfn_sb->dataoff.

Signed-off-by: Dave Jiang <dave.ji...@intel.com>
---
 drivers/nvdimm/pfn_devs.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index a2ac9e6..fa5ba33 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -527,11 +527,36 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct 
nd_pfn *nd_pfn,
                .base_pfn = init_altmap_base(base),
                .reserve = init_altmap_reserve(base),
        };
+       sector_t sector;
+       resource_size_t meta_start, meta_size;
+       long cleared;
+       unsigned int sz_align;
 
        memcpy(res, &nsio->res, sizeof(*res));
        res->start += start_pad;
        res->end -= end_trunc;
 
+       meta_start = res->start + SZ_8K;
+       meta_size = offset;
+
+       sector = meta_start >> 9;
+       sz_align = ALIGN(meta_size + (meta_start & (512 - 1)), 512);
+
+       if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) {
+               if (!IS_ALIGNED(meta_start, 512) ||
+                   !IS_ALIGNED(meta_size, 512))
+                       return ERR_PTR(-EIO);
+
+               cleared = nvdimm_clear_poison(&nd_pfn->dev,
+                                             meta_start, meta_size);
+               if (cleared <= 0)
+                       return ERR_PTR(-EIO);
+
+               badblocks_clear(&nsio->bb, sector, cleared >> 9);
+               if (cleared != meta_size)
+                       return ERR_PTR(-EIO);
+       }
+
        if (nd_pfn->mode == PFN_MODE_RAM) {
                if (offset < SZ_8K)
                        return ERR_PTR(-EINVAL);

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