If you delete a file with a hash and then create another file with
the same hash, sometimes on EFS filesystems while trying to create
the new file, it returns true to the file_exists check even though
the file doesn't exist, but then fails other calls.
This change makes Moodle tolerate that behaviour.
Allow both UI and automated backups to be created without
including files. Instead include only file references.
This is essentially implementing "SAMESITE" to backup files
instead of only for import and export functionality.
A new backup setting to include files (defaults to yes)
has been included.
The restore process will also look for and attempt to
restore files from the trashdir as part of restoring
backups. Additionally to support this process the
ammount of time files are kept in trashdir before they
are cleaned up via cron is also adjustable via admin
setting.
This addresses an edge scenario on NFS filesystems with no space
remaining, where subsequent uploads fail silently while zero byte files
are saved to the pool (and for some reason the filesize check passes).
This change moves all operations which deal with the fetching/updating, or
setting of files from the file_storage class into a new file_system class.
A new file_system can be specified in the config.php and used to replace
all relevant methods in order to move the file system component to an
alternative solution.
