When a file has its modtime set while it is open we delay setting the
modtime until the file is closed.
The file is then uploaded in Flush. In Release we check the cached
file has been uploaded by comparing modtimes and or hashes and upload
it again if it has changed.
Before this change we forgot to change the time on the cached file
when we updated the time file on the object, so this mean that Release
reset the time to the wrong time and uploaded the file again on
remotes which don't support hashes (eg crypt).
The fix was to set the modtime of the cached file at the same time we
set the modtime of the remote object. This means that the files check
as identical in Release so it doesn't try to upload the file.
This means that we avoid a double upload and the modtime is correct.
See: https://forum.rclone.org/t/modification-time-with-vfs-cache/13906/8
Before this change the expect/continue timeout was set to
--conntimeout which was 60s by default which is too long to wait.
This was noticed when using s3 with a proxy which apparently didn't
support expect / continue properly.
Set --expect-continue-timeout 0 to disable expect/continue.
Before this change we used non multipart uploads for files of unknown
size (streaming and uploads in mount). This is slower and less
reliable and is not recommended by Google for files smaller than 5MB.
After this change we use multipart resumable uploads for all files of
unknown length. This will use an extra transaction so is less
efficient for files under the chunk size, however the natural
buffering in the operations.Rcat call specified by
`--streaming-upload-cutoff` will overcome this.
See: https://forum.rclone.org/t/upload-behaviour-and-speed-when-using-vfs-cache/9920/
Unfortunately bcrypt only hashes the first 72 bytes of a given input
which meant that using it on ssh keys which are longer than 72 bytes
was incorrect.
This swaps over to using sha256 which should be adequate for the
purpose of protecting in memory passwords where the unencrypted
password is likely in memory too.
Before this change, when uploading files from the VFS cache which were
pending a rename, rclone would use the new path of the object when
specifiying the destination remote. This didn't cause a problem with
most backends as the subsequent rename did nothing, however with the
drive backend, since it updates objects, the incorrect Remote was
embedded in the object. This caused the rename to apparently succeed
but the object be at the wrong location.
The fix for this was to make sure we upload to the path stored in the
object if available.
This problem was spotted by the new rename tests for the VFS layer.
