[GIT PULL 51/58] lightnvm: pblk: add l2p crc debug printouts

From: Matias BjÃrling
Date: Fri Oct 13 2017 - 08:51:19 EST


From: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>

Print the CRC of the logical-to-physical mapping during exit and
after recovering the L2P table to facilitate detection of meta
data corruption/recovery issues.

The CRC printed after recovery should match the CRC printed during
the previous exit - if it doesn't this indicates that either the meta
data written to the disk is corrupt or recovery failed.

Signed-off-by: Hans Holmberg <hans.holmberg@xxxxxxxxxxxx>
Signed-off-by: Matias BjÃrling <m@xxxxxxxxxxx>
---
drivers/lightnvm/pblk-init.c | 39 ++++++++++++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index ad9f014..52c85f4 100644
--- a/drivers/lightnvm/pblk-init.c
+++ b/drivers/lightnvm/pblk-init.c
@@ -76,6 +76,28 @@ static blk_qc_t pblk_make_rq(struct request_queue *q, struct bio *bio)
return BLK_QC_T_NONE;
}

+static size_t pblk_trans_map_size(struct pblk *pblk)
+{
+ int entry_size = 8;
+
+ if (pblk->ppaf_bitsize < 32)
+ entry_size = 4;
+
+ return entry_size * pblk->rl.nr_secs;
+}
+
+#ifdef CONFIG_NVM_DEBUG
+static u32 pblk_l2p_crc(struct pblk *pblk)
+{
+ size_t map_size;
+ u32 crc = ~(u32)0;
+
+ map_size = pblk_trans_map_size(pblk);
+ crc = crc32_le(crc, pblk->trans_map, map_size);
+ return crc;
+}
+#endif
+
static void pblk_l2p_free(struct pblk *pblk)
{
vfree(pblk->trans_map);
@@ -85,12 +107,10 @@ static int pblk_l2p_init(struct pblk *pblk)
{
sector_t i;
struct ppa_addr ppa;
- int entry_size = 8;
+ size_t map_size;

- if (pblk->ppaf_bitsize < 32)
- entry_size = 4;
-
- pblk->trans_map = vmalloc(entry_size * pblk->rl.nr_secs);
+ map_size = pblk_trans_map_size(pblk);
+ pblk->trans_map = vmalloc(map_size);
if (!pblk->trans_map)
return -ENOMEM;

@@ -508,6 +528,10 @@ static int pblk_lines_configure(struct pblk *pblk, int flags)
}
}

+#ifdef CONFIG_NVM_DEBUG
+ pr_info("pblk init: L2P CRC: %x\n", pblk_l2p_crc(pblk));
+#endif
+
/* Free full lines directly as GC has not been started yet */
pblk_gc_free_full_lines(pblk);

@@ -901,6 +925,11 @@ static void pblk_exit(void *private)
down_write(&pblk_lock);
pblk_gc_exit(pblk);
pblk_tear_down(pblk);
+
+#ifdef CONFIG_NVM_DEBUG
+ pr_info("pblk exit: L2P CRC: %x\n", pblk_l2p_crc(pblk));
+#endif
+
pblk_free(pblk);
up_write(&pblk_lock);
}
--
2.9.3