After numerous tests it was found the splice features were at best
the same performance as standard IO and at worse actually slower.
To simplify the code all splice features are removed.
mergerfs tries to pass through ioctl calls but due to the complexity
of btrfs calls their is risk of segfaults. In the future it may be
required to whitelist all supported ioctl calls.
* Remove request interrupt code. Required tracking of all requests unnecesssarily.
* Remove all debugging printing. Have plans to do full replacement.
* Remove deprecated functions.
* Remove unneeded error checking.
* Remove "userdata" which was unused.
* Remove allow_root feature.
While they were going to be the new way of interacting with the runtime config
I've decided to use toml based config for mergerfs v3. In that case all updates
will happen through the config file and ioctl will only be used to load/reload
the config rather than a key:value like API.
* follow-symlinks: allows mergerfs to transparently follow symlinks
* link-exdev: in the event a link returns EXDEV create a symlink instead
* rename-exdev: in the event a rename returns EXDEV move the oldpath and
create a symlink for the newpath
chmod, chown, removexattr, setxattr, truncate, utimens:
* if no errors: return 0
* if no successes: return first error
* if file acted on was the same as related search function: return its value
* return 0
rmdir, unlink:
* if no errors: return 0
* return first error
Percentage Free Random Distribution
Chooses a random branch based on the available space percentage free.
IE: if branch A has 1G free and branch B has 2G then B should be chosen
twice as often.