Time Machine failed, smb error stat_ex.st_ex_blocks differs

In this case network hardware (realtek NIC) was dropping during time machine backup. Durable reconnect was denied because the stat output differed between our durable cooking and what was on-disk.

This is how durable handles are implemented in Samba and so there's nothing to be fixed.

Nov 26 15:33:21 freenas re0: watchdog timeout
Nov 26 15:33:21 freenas kernel: re0: link state changed to DOWN
Nov 26 15:33:21 freenas kernel: re0: link state changed to DOWN
Nov 26 15:33:25 freenas dhclient: New IP Address (re0): 192.168.178.43
Nov 26 15:33:25 freenas dhclient: New Subnet Mask (re0): 255.255.255.0
Nov 26 15:33:25 freenas dhclient: New Broadcast Address (re0): 192.168.178.255
Nov 26 15:33:25 freenas dhclient: New Routers (re0): 192.168.178.1
Nov 26 15:33:25 freenas kernel: re0: link state changed to UP
Nov 26 15:33:25 freenas kernel: re0: link state changed to UP

From a practical standpoint it may not be a bad idea to look into replacing the NIC with something better supported.

I intend to retest on the latest freenas release soon. I'll keep you posted.

Haven't had time to evaluate effect of network outages on TM backups and durable reconnects yet.

Try the newer RealTek driver in U4. This has solved the Watchdog timeouts network outages I was seeing:
https://jira.ixsystems.com/browse/NAS-108091?focusedCommentId=135041&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-135041