Am 12.06.2024 um 14:43 hat Amjad Alsharafi geschrieben:
> Added several tests to verify the implementation of the vvfat driver.
>
> We needed a way to interact with it, so created a basic `fat16.py` driver
> that handled writing correct sectors for us.
>
> Added `vvfat` to the non-generic formats, as its not a normal image format.
>
> Signed-off-by: Amjad Alsharafi <amjadsharaf...@gmail.com>
> + def truncate_file(
> + self,
> + entry: FatDirectoryEntry,
> + new_size: int,
> + allocate_non_continuous: bool = False,
> + ):
> + """
> + Truncate the file at the given path to the new size.
> + """
> + if entry is None:
> + return Exception("entry is None")
> + if entry.attributes & 0x10 != 0:
> + raise Exception(f"{entry.whole_name()} is a directory")
> +
> + def clusters_from_size(size: int):
> + return (
> + size + self.boot_sector.cluster_bytes() - 1
> + ) // self.boot_sector.cluster_bytes()
> +
> + # First, allocate new FATs if we need to
> + required_clusters = clusters_from_size(new_size)
> + current_clusters = clusters_from_size(entry.size_bytes)
> +
> + affected_clusters = set()
> +
> + # Keep at least one cluster, easier to manage this way
> + if required_clusters == 0:
> + required_clusters = 1
> + if current_clusters == 0:
> + current_clusters = 1
> +
> + if required_clusters > current_clusters:
> + # Allocate new clusters
> + cluster = entry.cluster
> + to_add = required_clusters
> + for _ in range(current_clusters - 1):
> + to_add -= 1
> + cluster = self.next_cluster(cluster)
> + assert required_clusters > 0, "No new clusters to allocate"
> + assert cluster is not None, "Cluster is None"
> + assert (
> + self.next_cluster(cluster) is None
> + ), "Cluster is not the last cluster"
> +
> + # Allocate new clusters
> + for _ in range(to_add - 1):
> + new_cluster = self.next_free_cluster()
> + if allocate_non_continuous:
> + new_cluster = self.next_free_cluster_non_continuous()
The normal self.next_free_cluster() could be in an else branch. No
reason to search for a free cluster when you immediately overwrite it
anyway.
> + self.write_fat_entry(cluster, new_cluster)
> + self.write_fat_entry(new_cluster, 0xFFFF)
> + cluster = new_cluster
> +
> + elif required_clusters < current_clusters:
> + # Truncate the file
> + cluster = entry.cluster
> + for _ in range(required_clusters - 1):
> + cluster = self.next_cluster(cluster)
> + assert cluster is not None, "Cluster is None"
> +
> + next_cluster = self.next_cluster(cluster)
> + # mark last as EOF
> + self.write_fat_entry(cluster, 0xFFFF)
> + # free the rest
> + while next_cluster is not None:
> + cluster = next_cluster
> + next_cluster = self.next_cluster(next_cluster)
> + self.write_fat_entry(cluster, 0)
> +
> + self.flush_fats()
> +
> + # verify number of clusters
> + cluster = entry.cluster
> + count = 0
> + while cluster is not None:
> + count += 1
> + affected_clusters.add(cluster)
> + cluster = self.next_cluster(cluster)
> + assert (
> + count == required_clusters
> + ), f"Expected {required_clusters} clusters, got {count}"
> +
> + # update the size
> + entry.size_bytes = new_size
> + self.update_direntry(entry)
> +
> + # trigger every affected cluster
> + for cluster in affected_clusters:
> + first_sector = self.boot_sector.first_sector_of_cluster(cluster)
> + first_sector_data = self.read_sectors(first_sector, 1)
> + self.write_sectors(first_sector, first_sector_data)
Other than this, the patch looks good to me and we seem to test all the
cases that are fixed by the previous patches.
Reviewed-by: Kevin Wolf <kw...@redhat.com>
Tested-by: Kevin Wolf <kw...@redhat.com>
Kevin
