lightnvm: pblk: add l2p crc debug printouts

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@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
index ad9f014a086b3b0a4904d22d4b2054c02941ca1f..52c85f4f672de395419b6417ad89932058aea44a 100644 (file)
--- 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;
-
-       if (pblk->ppaf_bitsize < 32)
-               entry_size = 4;
+       size_t map_size;
 
-       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);
 }