Exception from HRESULT: 0x80131904

Over the years, I've periodically encountered an issue in which SharePoint will give you the following error message whenever you attempt to perform some simple write, update, or delete operations on a site (i.e. like adding a new list item to a SharePoint list):

Exception from HRESULT: 0x80131904

In my experience, this error message is indicating that SharePoint is not able to write information to the content database and the most common cause that I've encountered is that the location where SQL logs are stored has run out of drive space (i.e. this being the SQL server that hosts the SharePoint content database).  Typically, we've either deleted the older SQL transaction logs stored here or simply moved them to another location with more drive space (i.e. archive) in order to free up space on that drive location.  Once that delete/move operation of the log files is complete and more drive space is available, the SharePoint environment will return to normal operation immediately.