libnvdimm, btt: ensure that initializing metadata clears poison

If we had badblocks/poison in the metadata area of a BTT, recreating the
BTT would not clear the poison in all cases, notably the flog area. This
is because rw_bytes will only clear errors if the request being sent
down is 512B aligned and sized.

Make sure that when writing the map and info blocks, the rw_bytes being
sent are of the correct size/alignment. For the flog, instead of doing
the smaller log_entry writes only, first do a 'wipe' of the entire area
by writing zeroes in large enough chunks so that errors get cleared.

Cc: Andy Rudoff <andy.rudoff@intel.com>
Cc: 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 aa977cd..983718b 100644 (file)
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -57,6 +57,14 @@ static int btt_info_write(struct arena_info *arena, struct btt_sb *super)
 {
        int ret;
 
+       /*
+        * infooff and info2off should always be at least 512B aligned.
+        * We rely on that to make sure rw_bytes does error clearing
+        * correctly, so make sure that is the case.
+        */
+       WARN_ON_ONCE(!IS_ALIGNED(arena->infooff, 512));
+       WARN_ON_ONCE(!IS_ALIGNED(arena->info2off, 512));
+
        ret = arena_write_bytes(arena, arena->info2off, super,
                        sizeof(struct btt_sb), 0);
        if (ret)
@@ -394,9 +402,17 @@ static int btt_map_init(struct arena_info *arena)
        if (!zerobuf)
                return -ENOMEM;
 
+       /*
+        * mapoff should always be at least 512B  aligned. We rely on that to
+        * make sure rw_bytes does error clearing correctly, so make sure that
+        * is the case.
+        */
+       WARN_ON_ONCE(!IS_ALIGNED(arena->mapoff, 512));
+
        while (mapsize) {
                size_t size = min(mapsize, chunk_size);
 
+               WARN_ON_ONCE(size < 512);
                ret = arena_write_bytes(arena, arena->mapoff + offset, zerobuf,
                                size, 0);
                if (ret)
@@ -418,11 +434,36 @@ static int btt_map_init(struct arena_info *arena)
  */
 static int btt_log_init(struct arena_info *arena)
 {
+       size_t logsize = arena->info2off - arena->logoff;
+       size_t chunk_size = SZ_4K, offset = 0;
+       struct log_entry log;
+       void *zerobuf;
        int ret;
        u32 i;
-       struct log_entry log, zerolog;
 
-       memset(&zerolog, 0, sizeof(zerolog));
+       zerobuf = kzalloc(chunk_size, GFP_KERNEL);
+       if (!zerobuf)
+               return -ENOMEM;
+       /*
+        * logoff should always be at least 512B  aligned. We rely on that to
+        * make sure rw_bytes does error clearing correctly, so make sure that
+        * is the case.
+        */
+       WARN_ON_ONCE(!IS_ALIGNED(arena->logoff, 512));
+
+       while (logsize) {
+               size_t size = min(logsize, chunk_size);
+
+               WARN_ON_ONCE(size < 512);
+               ret = arena_write_bytes(arena, arena->logoff + offset, zerobuf,
+                               size, 0);
+               if (ret)
+                       goto free;
+
+               offset += size;
+               logsize -= size;
+               cond_resched();
+       }
 
        for (i = 0; i < arena->nfree; i++) {
                log.lba = cpu_to_le32(i);
@@ -431,13 +472,12 @@ static int btt_log_init(struct arena_info *arena)
                log.seq = cpu_to_le32(LOG_SEQ_INIT);
                ret = __btt_log_write(arena, i, 0, &log, 0);
                if (ret)
-                       return ret;
-               ret = __btt_log_write(arena, i, 1, &zerolog, 0);
-               if (ret)
-                       return ret;
+                       goto free;
        }
 
-       return 0;
+ free:
+       kfree(zerobuf);
+       return ret;
 }
 
 static int btt_freelist_init(struct arena_info *arena)