From your dmesg.txt log file the error is
[ 1679.865539] JBD: Detected IO errors while flushing file data on sda1
This is usually due to a corrupted filesystem or a faulty media. You should run a filesystem check on your western digital drive because it may lead to data loss.
I'm closing this report because it's not a bug with Ubuntu.
Thanks for your report.
From your dmesg.txt log file the error is
[ 1679.865539] JBD: Detected IO errors while flushing file data on sda1
This is usually due to a corrupted filesystem or a faulty media. You should run a filesystem check on your western digital drive because it may lead to data loss.
I'm closing this report because it's not a bug with Ubuntu.