Description of problem: When booting SANboot RHEL 6.0 DMMP with the SANboot LUN owned by the alternate path on the storage array along with having LUNs mapped from multiple arrays, the OS begins to boot but then hangs reporting "INFO: task jbd2/dm-67-8:3367 blocked for more than 120 seconds." 

Version-Release number of selected component (if applicable):
RHEL 6.0

How reproducible:
The issue occurs everytime when trying to boot the SANboot LUN from the alterate path with additional LUNs mapped.

Steps to Reproduce:
1. Create 80 GB LUN (for SANboot).
2. Install OS to the SANboot LUN.
3. The SANboot LUN as well as 64 additional LUNs (32 from each array) are mapped to the host
3. Host is restarted to configure hba to boot from alternate controller
4. Reboot host.
  
Actual results:
The host begins to boot but hangs with message "INFO: task jbd2/dm-67-8:3367 blocked for more than 120 seconds."

Expected results:
OS boots up without any issues.

Additional info: We are seeing this issue using a QMI8142 Manteo FCoE HBA going to DS3500 and DS5300 arrays; iSCSI using Emulex eRaptor CNA (P/N: 49Y4235) going to two DS3500 arrays; and an IBM HS22 Blade server using a Meteorite (IBM P/N 43W3974) SAS pass-thru adapter going to DS3500 and DS3200 arrays.