drbd: introduce the "initialized" activity log transaction type

So we can initialize a clean on disk activity log area,
without the module complaining with loud assert messages
because of checksum or magic value mismatches.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 586776195a79..90ebbbb3dc27 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -31,6 +31,11 @@
 #include "drbd_int.h"
 #include "drbd_wrappers.h"
 
+
+enum al_transaction_types {
+        AL_TR_UPDATE = 0,
+        AL_TR_INITIALIZED = 0xffff
+};
 /* all fields on disc in big endian */
 struct __packed al_transaction_on_disk {
         /* don't we all like magic */
@@ -44,7 +49,8 @@ struct __packed al_transaction_on_disk {
         __be32  crc32c;
 
         /* type of transaction, special transaction types like:
-         * purge-all, set-all-idle, set-all-active, ... to-be-defined */
+         * purge-all, set-all-idle, set-all-active, ... to-be-defined
+         * see also enum al_transaction_types */
         __be16  transaction_type;
 
         /* we currently allow only a few thousand extents,
@@ -476,6 +482,7 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
         int active_extents = 0;
         int transactions = 0;
         int found_valid = 0;
+        int found_initialized = 0;
         int from = 0;
         int to = 0;
         u32 from_tnr = 0;
@@ -504,6 +511,10 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
                 /* invalid data in that block */
                 if (rv == 0)
                         continue;
+                if (be16_to_cpu(b->transaction_type) == AL_TR_INITIALIZED) {
+                        ++found_initialized;
+                        continue;
+                }
 
                 /* IO error */
                 if (rv == -1) {
@@ -535,7 +546,8 @@ int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
         }
 
         if (!found_valid) {
-                dev_warn(DEV, "No usable activity log found.\n");
+                if (found_initialized != mx)
+                        dev_warn(DEV, "No usable activity log found.\n");
                 mutex_unlock(&mdev->md_io_mutex);
                 return 1;
         }