thin-provisioning-tools/functional-tests/check-superblock.scm

152 lines
4.9 KiB
Scheme

(import
(fmt fmt)
(matchable))
;;;;---------------------------------------------------
;;;; Constants
;;;;---------------------------------------------------
;; FIXME: duplicate with main.scm
(define (current-metadata)
"./metadata.bin")
(define metadata-block-size 4096)
(define superblock-magic 27022010)
(define superblock-salt 160774)
(define uuid-size 16)
(define space-map-root-size 128)
;;;;---------------------------------------------------
;;;; Metadata IO
;;;;---------------------------------------------------
(define (open-metadata path)
(open-file-input-port path (file-options) (buffer-mode none)))
(define-syntax with-metadata
(syntax-rules ()
((_ (port path) body ...) (let ((port (open-metadata path)))
(dynamic-wind
(lambda () #f)
(lambda () body ...)
(lambda () (close-port port)))))))
;; FIXME: return our own condition?
(define (io-error msg)
(raise (condition
(make-error)
(make-message-condition msg))))
;;; Returns a 4k bytevector
(define (read-block port b)
(set-port-position! port (* b metadata-block-size))
(let ((data (get-bytevector-n port metadata-block-size)))
(unless (and (not (eof-object? data))
(= metadata-block-size (bytevector-length data)))
(io-error (fmt #f (dsp "unable to read metadata block: ") (num b))))
data))
;;;;---------------------------------------------------
;;;; CRC32
;;;;---------------------------------------------------
;; FIXME: move to own library
(load-shared-object "libz.so")
(define crc32
(foreign-procedure "crc32" (unsigned-long u8* unsigned-int) unsigned-long))
(define crc32-combine
(foreign-procedure "crc32_combine" (unsigned-long unsigned-long unsigned-long) unsigned-long))
;; FIXME: stop copying the bytevector. I'm not sure how to pass an offset into
;; the bv.
(define (crc32-region salt bv start end)
(assert (< start end))
(let ((len (- end start)))
(let ((copy (make-bytevector len)))
(bytevector-copy! bv start copy 0 len)
(let ((crc (crc32 salt copy 0)))
(crc32 crc copy len)))))
;;;;---------------------------------------------------
;;;; Decoding
;;;;---------------------------------------------------
(define-syntax unpack-type
(syntax-rules (le32 le64 bytes)
((_ bv offset le32)
(bytevector-u32-ref bv offset (endianness little)))
((_ bv offset le64)
(bytevector-u64-ref bv offset (endianness little)))
((_ bv offset (bytes count))
(let ((copy (make-bytevector count)))
(bytevector-copy! bv offset copy 0 count)
copy))))
(define (size-type t)
(syntax->datum
(syntax-case t (le32 le64 bytes)
(le32 #'4)
(le64 #'8)
((bytes count) #'count))))
(define-syntax binary-format
(lambda (x)
(syntax-case x ()
((_ (name pack-name unpack-name) (field type) ...)
(with-syntax ((((t o) ...)
(let f ((acc 0) (types #'(type ...)))
(if (null? types)
'()
(cons (list (car types) acc)
(f (+ acc (size-type (car types))) (cdr types)))))))
#'(begin
(define-record-type name (fields field ...))
(define (unpack-name bv offset)
((record-constructor (record-type-descriptor name))
(unpack-type bv (+ offset o) t) ...))))))))
(binary-format (superblock pack-superblock unpack-superblock)
(csum le32)
(flags le32)
(block-nr le64)
(uuid (bytes 16))
(magic le64)
(version le32)
(time le32)
(trans-id le64)
(metadata-snap le64)
(data-space-map-root (bytes 128))
(metadata-space-map-root (bytes 128))
(data-mapping-root le64)
(device-details-root le64)
(data-block-size le32)
(metadata-block-size le32)
(metadata-nr-blocks le64)
(compat-flags le32)
(compat-ro-flags le32)
(incompat-flags le32))
;;;;---------------------------------------------------
;;;; Top level
;;;;---------------------------------------------------
(define (check-magic sb)
((let ((m (bytevector-u32-ref sb 32 (endianness little))))
(fmt #t (dsp "on disk magic: ") (num m) nl)
)))
(define (read-superblock)
(with-metadata (md (current-metadata))
(unpack-superblock (read-block md 0) 0)))
(define (check-superblock)
(with-metadata (md (current-metadata))
(let ((superblock (read-block md 0)))
(fmt #t (dsp "checksum on disk: ") (dsp (bytevector-u32-ref superblock 0 (endianness little))) nl)
(fmt #t (dsp "calculated checksum: ") (dsp (crc32-region superblock-salt superblock 4 4092)) nl)
(check-magic superblock))))