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guix/tests/store-deduplication.scm
Ludovic Courtès adb158b739
deduplication: Gracefully handle ENOSPC raised by 'link' calls.
Reported by Andreas Enge <andreas@enge.fr>
in <https://bugs.gnu.org/33676>.

* guix/store/deduplication.scm (replace-with-link): Catch ENOSPC around
'get-temp-link'.  Do nothing when 'get-temp-link' throws ENOSPC.  Move
code to restore PARENT's permissions outside of 'catch'.
* tests/store-deduplication.scm ("deduplicate, ENOSPC"): New test.
2018-12-14 12:07:24 +01:00

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (test-store-deduplication)
#:use-module (guix tests)
#:use-module (guix store deduplication)
#:use-module (gcrypt hash)
#:use-module ((guix utils) #:select (call-with-temporary-directory))
#:use-module (guix build utils)
#:use-module (rnrs bytevectors)
#:use-module (ice-9 binary-ports)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-64))
(test-begin "store-deduplication")
(test-equal "deduplicate"
(cons* #t #f ;inode comparisons
2 (make-list 5 6)) ;'nlink' values
(call-with-temporary-directory
(lambda (store)
(let ((data (string->utf8 "Hello, world!"))
(identical (map (lambda (n)
(string-append store "/" (number->string n)
"/a/b/c"))
(iota 5)))
(unique (string-append store "/unique")))
(for-each (lambda (file)
(mkdir-p (dirname file))
(call-with-output-file file
(lambda (port)
(put-bytevector port data))))
identical)
;; Make the parent of IDENTICAL read-only. This should not prevent
;; deduplication from inserting its hard link.
(chmod (dirname (second identical)) #o544)
(call-with-output-file unique
(lambda (port)
(put-bytevector port (string->utf8 "This is unique."))))
(deduplicate store (nar-sha256 store) #:store store)
;; (system (string-append "ls -lRia " store))
(cons* (apply = (map (compose stat:ino stat) identical))
(= (stat:ino (stat unique))
(stat:ino (stat (car identical))))
(stat:nlink (stat unique))
(map (compose stat:nlink stat) identical))))))
(test-equal "deduplicate, ENOSPC"
(cons* #f ;inode comparison
(append (make-list 3 4)
(make-list 7 1))) ;'nlink' values
;; In this scenario the first 3 files are properly deduplicated and then we
;; simulate a full '.links' directory where link(2) gets ENOSPC, thereby
;; preventing deduplication of the subsequent files.
(call-with-temporary-directory
(lambda (store)
(let ((true-link link)
(links 0)
(data1 (string->utf8 "Hello, world!"))
(data2 (string->utf8 "Hi, world!"))
(identical (map (lambda (n)
(string-append store "/" (number->string n)
"/a/b/c"))
(iota 10)))
(populate (lambda (data)
(lambda (file)
(mkdir-p (dirname file))
(call-with-output-file file
(lambda (port)
(put-bytevector port data)))))))
(for-each (populate data1) (take identical 5))
(for-each (populate data2) (drop identical 5))
(dynamic-wind
(lambda ()
(set! link (lambda (old new)
(set! links (+ links 1))
(if (<= links 3)
(true-link old new)
(throw 'system-error "link" "~A" '("Whaaat?!")
(list ENOSPC))))))
(lambda ()
(deduplicate store (nar-sha256 store) #:store store))
(lambda ()
(set! link true-link)))
(cons (apply = (map (compose stat:ino stat) identical))
(map (compose stat:nlink stat) identical))))))
(test-end "store-deduplication")