When I run this code specifying a 16TB disk:
//
// main.swift
// walking_on_directories
//
//
import Foundation
import CommonCrypto
import Foundation
func sha256Checksum(forFileAtPath path: String) -> String? {
// Open the file for reading
guard let file = FileHandle(forReadingAtPath: path) else {
return nil
}
defer {
file.closeFile()
}
// Initialize the SHA-256 context
var context = CC_SHA256_CTX()
CC_SHA256_Init(&context)
// Read the file in chunks and update the context
let chunkSize = 1024 * 1024 // 1 MB
while autoreleasepool(invoking: {
let data = file.readData(ofLength: chunkSize)
if !data.isEmpty {
data.withUnsafeBytes {
_ = CC_SHA256_Update(&context, $0.baseAddress, CC_LONG(data.count))
}
return true
} else {
return false
}
}) {}
// Finalize the context and get the checksumt
var digest = [UInt8](repeating: 0, count: Int(CC_SHA256_DIGEST_LENGTH))
CC_SHA256_Final(&digest, &context)
let checksum = digest.map { String(format: "%02hhx", $0) }.joined()
return checksum
}
let startLocation = "/Volumes/16-1-23/debug_file_tracker/images"
let fileManager = FileManager.default
let enumerator:FileManager.DirectoryEnumerator = fileManager.enumerator(atPath:startLocation)!
var count = 0
while let element = enumerator.nextObject() as? String {
var existing_files_checksum = Set<String>()
var isDirectory: ObjCBool = false
let filePath: String = startLocation + "/" + element
if fileManager.fileExists(atPath: filePath, isDirectory: &isDirectory) {
if isDirectory.boolValue {
print("Skipping directory: " + filePath)
}else {
if let checksum = sha256Checksum(forFileAtPath: filePath) {
if existing_files_checksum.contains(checksum) {
print("deleting " + filePath)
try fileManager.removeItem(atPath: filePath)
count = count + 1
} else {
print("adding " + checksum)
existing_files_checksum.insert(checksum)
}
} else {
print("Failed to calculate checksum for " + filePath)
}
}
}
}
print("deleted " + String(count) + " files")
It runs for hours, printing checksums.
It calculates the checksum for about 17,000 files.
Then my disk breaks.
Here's what I mean by breaks:
Before running the program:The disk checkout out with disktutil, It is fine:
ls
shows
/volumes/16-1-23
But then, this program crashes because it can't find the next file to checksum.
When I do an
ls -al /volumes/16-1-23
the command returns permission denied.
sudo ls -al
total 0
d--x--x--x 2 root wheel 64 Apr 23 19:16 .
drwxr-xr-x 23 sam wheel 736 Apr 24 09:03 ..
when I do an
ls /volumes
I see:
ls -al
total 96
drwxr-xr-x 23 sam wheel 736 Apr 24 09:19 .
drwxr-xr-x 20 root wheel 640 Apr 1 12:46 ..
d--x--x--x 2 root wheel 64 Apr 23 19:16 16-1-23
d--x--x--x 2 root wheel 64 Apr 23 21:59 16-1-23 1
d--x--x--x 2 root wheel 64 Apr 24 04:09 16-1-23 10
d--x--x--x 2 root wheel 64 Apr 24 08:13 16-1-23 11
drwx------@ 14 sam staff 448 Apr 15 15:42 16-1-23 12
d--x--x--x 2 root wheel 64 Apr 23 22:14 16-1-23 2
d--x--x--x 2 root wheel 64 Apr 23 23:04 16-1-23 3
d--x--x--x 2 root wheel 64 Apr 23 23:04 16-1-23 4
d--x--x--x 2 root wheel 64 Apr 24 00:13 16-1-23 5
d--x--x--x 2 root wheel 64 Apr 24 00:13 16-1-23 6
d--x--x--x 2 root wheel 64 Apr 24 01:08 16-1-23 7
d--x--x--x 2 root wheel 64 Apr 24 02:01 16-1-23 8
d--x--x--x 2 root wheel 64 Apr 24 03:05 16-1-23 9
drwxrwxr-x@ 9 sam staff 288 Apr 7 13:06 16-3-23
all of the "disks" ending in a number e.g
16-1-23 9
aren't accessible.
sudo ls -al 1 ↵
Password:
total 0
shows:
d--x--x--x 2 root wheel 64 Apr 24 03:05 .
drwxr-xr-x 23 sam wheel 736 Apr 24 09:19 ..
Diskuitil didn't find any errors.
I'd really love to know what's going on.
I can produce this error with Python code that does the same thing.
I was hoping that the problem would go away if I wrote it in Swift.
It didn't.
I guess that's good.
However, now am I really stuck.
Any advice appreciated.