efi_pstore: Add a format check for an existing variable name at erasing time

[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 add a format check for the old variable name in a erase callback to make it erasable.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index bf7a6f994a3cf8bd14161c88a132f634867b5203..6e51c1e81f143bd8f44abe1b01bb1915fb584e93 100644 (file)
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -773,6 +773,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
 {
        char name[DUMP_NAME_LEN];
        efi_char16_t efi_name[DUMP_NAME_LEN];
+       char name_old[DUMP_NAME_LEN];
+       efi_char16_t efi_name_old[DUMP_NAME_LEN];
        efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
        struct efivars *efivars = psi->data;
        struct efivar_entry *entry, *found = NULL;
@@ -796,8 +798,22 @@ 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.
+                        */
+                       sprintf(name_old, "dump-type%u-%u-%lu", type,
+                               (unsigned int)id, time.tv_sec);
+
+                       for (i = 0; i < DUMP_NAME_LEN; i++)
+                               efi_name_old[i] = name_old[i];
+
+                       if (utf16_strncmp(entry->var.VariableName, efi_name_old,
+                                         utf16_strlen(efi_name_old)))
+                               continue;
+               }
 
                /* found */
                found = entry;