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>

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 5867761..90ebbbb 100644 (file)
--- 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;
        }