* fixes#22819
The old way fired a DELETE statement on each destruction of the
DBLockingProvider. Which could cause a lot of queries. It's enough
to run this every 5 minutes in a background job, which in the end
could result in file locks that exists 5 minutes longer - in the
worst case and for not properly released locks.
This makes the DB based locking a lot more performant and could
result in a similar performance to the Redis based locking provider.
When calling `\OC\Files\View::copy` we should also keep the version to ensure that the file will always have the correct version attached and can be successfully decrypted.
To test this the following steps are necessary (from https://github.com/owncloud/core/issues/22781#issuecomment-191328982):
1. setup a new ownCloud 9.0 beta2
2. enable encryption
2. upload a docx (5.7MB large)
3. upload the same file again and overwrite the existing file
4. I can download the original file and the first version
5. I restore the first version
6. restored version can no longer be downloaded with the error described above
The manual cache operation in `\OCA\Files_Versions\Storage` is unfortunately necessary since `\OCA\Files_Versions\Storage::copyFileContents` is not using `\OCP\Files\Storage::moveFromStorage` in the case when an object storage is used. Due to the workaround added in 54cea05271 the stream is directly copied and thus bypassing the FS.
We should not scan any custom data directory in the integrity checker as well. Otherwise this would lead to a massive increased update time that may likely exceed the timeout.
To test this:
1. Install ownCloud 8.2.2, set as data dir another folder than `data` such as `data-asdf`. Make sure that folder lives in the web root as well.
2. Update that instance to 9.0.0 beta2 => Errors are shown in the code integrity check
3. Apply this patch and trigger the rescan in the admin settings => No errors are shown anymore (can also do a new update with that patch applied)
Fixes https://github.com/owncloud/core/issues/22698
When we overwrite a checksumed file with a file without a checksum we
should remove the checksum from the server.
This is done by setting the column to empty.
* Upload file with checksum
* Chunked upload with checksum
* Copy file with checksum should also copy the checksum
* Moving a file with checksum should also move the checksum
* Uploading a file with checksum and overwriting it with a file without cheksum should remove the checksum
