[Issue]

A format of variable name has been updated to type, id, count and ctime
to support holding multiple logs.

Format of current variable name
  dump-type0-1-2-12345678

  type:0
  id:1
  count:2
  ctime:12345678

On the other hand, if an old variable name before being updated
remains, users can't erase it via /dev/pstore.

Format of old variable name
  dump-type0-1-12345678

  type:0
  id:1
  ctime:12345678

[Solution]

This patch adds a format check for the old variable name in a erase callback to make it erasable.

Signed-off-by: Seiji Aguchi <redacted>
---
 drivers/firmware/efivars.c |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index dd228d5..b1cd028 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c

@@ -777,6 +777,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
        struct efivars *efivars = psi->data;
        struct efivar_entry *entry, *found = NULL;
        int i;
+       unsigned int type_old, part_old;
+       unsigned long time_old;

        sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
                time.tv_sec);

@@ -796,8 +798,16 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
                if (efi_guidcmp(entry->var.VendorGuid, vendor))
                        continue;
                if (utf16_strncmp(entry->var.VariableName, efi_name,
-                                 utf16_strlen(efi_name)))
-                       continue;
+                                 utf16_strlen(efi_name))) {
+                       /*
+                        * Check if an old format,
+                        * which doesn't support holding
+                        * multiple logs, remains.
+                        */
+                       if (sscanf(name, "dump-type%u-%u-%lu",
+                                  &type_old, &part_old, &time_old) != 3)