I ran a "btrfs check" on one of the partitions that had issues last night to confirm that the file system was not damaged. No errors were found.
# btrfs check -p /dev/sdc1
Checking filesystem on /dev/sdc1
UUID: d6640b4b-bd59-47d5-bfd7-37b4c40fb3c6
checking extents [.]
checking free space cache [o]
checking fs roots [O]
checking only csum items (without verifying data)
checking root refs
found 1453455912960 bytes used, no error found
total csum bytes: 1411701148
total tree bytes: 7534133248
total fs tree bytes: 3358851072
total extent tree bytes: 2426896384
btree space waste bytes: 695281951
file data blocks allocated: 3067911655424
referenced 6563527507968
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Russell Mosemann