How to repair HFS+ partition?

Solution 1:

The partition map is completely valid - the CoreStorage stack is messed up though.

After creating a CoreStorage stack (e.g by enabling FileVault) the CoreStorage logical volume group should contain at least one physical volume, one logical volume family and a logical volume.

In your case the last two are missing due to CS stack corruption. The output of diskutil cs list in your question should also show a logical volume family and a logical volume.

In rare cases this may be repaired by booting to (Internet) Recovery Mode and opening Terminal in the menubar > Utilites:

Check the CS stack:

fsck_cs /dev/rdisk0s2

Repair it:

diskutil repairDisk /dev/disk0

If the latter fails restore your main volume using a current Time Machine backup. If you don't have a backup dd disk0 to a raw image and hope that someone comes up with a solution to repair or recover filevaulted data. I learned a lot about FileVault here - check the links (e.g. Infiltrate the Vault: Security Analysis and Decryption of Lion Full Disk Encryption) there also!