Add new generic_attributes attribute in Node.
Use the generic attributes to add support for creation time and file attributes like hidden, readonly, encrypted in windows. Handle permission errors for readonly files in windows.
Handle backup and restore of encrypted attributes using windows system calls.
LoadBlobsFromPack is now part of the repository struct. This ensures
that users of that method don't have to deal will internals of the
repository implementation.
The filerestorer tests now also contain far fewer pack file
implementation details.
Writing these blobs to their files can take a long time and consequently
cause the backend connection to time out. Avoid that by retrieving these
blobs separately.
For hardlinked files, only the first instance of that file increases the
amount of bytes to restore. All later instances only increase the file
count but not the restore size.
Mostly changed the ones that repeat the name of a system call, which is
already contained in os.PathError.Op. internal/fs.Reader had to be
changed to actually return such errors.
TestRepository and its variants always returned no-op cleanup functions.
If they ever do need to do cleanup, using testing.T.Cleanup is easier
than passing these functions around.
The ioutil functions are deprecated since Go 1.17 and only wrap another
library function. Thus directly call the underlying function.
This commit only mechanically replaces the function calls.
Sparse files contain large regions containing only zero bytes. Checking
that a blob only contains zeros is possible with over 100GB/s for modern
x86 CPUs. Calculating sha256 hashes is only possible with 500MB/s (or
2GB/s using hardware acceleration). Thus we can speed up the hash
calculation for all zero blobs (which always have length
chunker.MinSize) by checking for zero bytes and then using the
precomputed hash.
The all zeros check is only performed for blobs with the minimal chunk
size, and thus should add no overhead most of the time. For chunks which
are not all zero but have the minimal chunks size, the overhead will be
below 2% based on the above performance numbers.
This allows reading sparse sections of files as fast as the kernel can
return data to us. On my system using BTRFS this resulted in about
4GB/s.
