diff options
Diffstat (limited to 'guix/store/deduplication.scm')
| -rw-r--r-- | guix/store/deduplication.scm | 102 |
1 files changed, 53 insertions, 49 deletions
diff --git a/guix/store/deduplication.scm b/guix/store/deduplication.scm index df959bdd06..0655ceb890 100644 --- a/guix/store/deduplication.scm +++ b/guix/store/deduplication.scm @@ -94,8 +94,8 @@ LINK-PREFIX." (try (tempname-in link-prefix)) (apply throw args)))))) -(define (call-with-writable-file file thunk) - (if (string=? file (%store-directory)) +(define (call-with-writable-file file store thunk) + (if (string=? file store) (thunk) ;don't meddle with the store's permissions (let ((stat (lstat file))) (dynamic-wind @@ -106,17 +106,18 @@ LINK-PREFIX." (set-file-time file stat) (chmod file (stat:mode stat))))))) -(define-syntax-rule (with-writable-file file exp ...) +(define-syntax-rule (with-writable-file file store exp ...) "Make FILE writable for the dynamic extent of EXP..., except if FILE is the store." - (call-with-writable-file file (lambda () exp ...))) + (call-with-writable-file file store (lambda () exp ...))) ;; There are 3 main kinds of errors we can get from hardlinking: "Too many ;; things link to this" (EMLINK), "this link already exists" (EEXIST), and ;; "can't fit more stuff in this directory" (ENOSPC). (define* (replace-with-link target to-replace - #:key (swap-directory (dirname target))) + #:key (swap-directory (dirname target)) + (store (%store-directory))) "Atomically replace the file TO-REPLACE with a link to TARGET. Use SWAP-DIRECTORY as the directory to store temporary hard links. Upon ENOSPC and EMLINK, TO-REPLACE is left unchanged. @@ -137,7 +138,7 @@ Note: TARGET, TO-REPLACE, and SWAP-DIRECTORY must be on the same file system." ;; If we couldn't create TEMP-LINK, that's OK: just don't do the ;; replacement, which means TO-REPLACE won't be deduplicated. (when temp-link - (with-writable-file (dirname to-replace) + (with-writable-file (dirname to-replace) store (catch 'system-error (lambda () (rename-file temp-link to-replace)) @@ -154,46 +155,49 @@ under STORE." (define links-directory (string-append store "/.links")) - (mkdir-p links-directory) - (let loop ((path path) - (type (stat:type (lstat path))) - (hash hash)) - (if (eq? 'directory type) - ;; Can't hardlink directories, so hardlink their atoms. - (for-each (match-lambda - ((file . properties) - (unless (member file '("." "..")) - (let* ((file (string-append path "/" file)) - (type (match (assoc-ref properties 'type) - ((or 'unknown #f) - (stat:type (lstat file))) - (type type)))) - (loop file type - (and (not (eq? 'directory type)) - (nar-sha256 file))))))) - (scandir* path)) - (let ((link-file (string-append links-directory "/" - (bytevector->nix-base32-string hash)))) - (if (file-exists? link-file) - (replace-with-link link-file path - #:swap-directory links-directory) - (catch 'system-error - (lambda () - (link path link-file)) - (lambda args - (let ((errno (system-error-errno args))) - (cond ((= errno EEXIST) - ;; Someone else put an entry for PATH in - ;; LINKS-DIRECTORY before we could. Let's use it. - (replace-with-link path link-file - #:swap-directory links-directory)) - ((= errno ENOSPC) - ;; There's not enough room in the directory index for - ;; more entries in .links, but that's fine: we can - ;; just stop. - #f) - ((= errno EMLINK) - ;; PATH has reached the maximum number of links, but - ;; that's OK: we just can't deduplicate it more. - #f) - (else (apply throw args))))))))))) + (mkdir-p links-directory) + (let loop ((path path) + (type (stat:type (lstat path))) + (hash hash)) + (if (eq? 'directory type) + ;; Can't hardlink directories, so hardlink their atoms. + (for-each (match-lambda + ((file . properties) + (unless (member file '("." "..")) + (let* ((file (string-append path "/" file)) + (type (match (assoc-ref properties 'type) + ((or 'unknown #f) + (stat:type (lstat file))) + (type type)))) + (loop file type + (and (not (eq? 'directory type)) + (nar-sha256 file))))))) + (scandir* path)) + (let ((link-file (string-append links-directory "/" + (bytevector->nix-base32-string hash)))) + (if (file-exists? link-file) + (replace-with-link link-file path + #:swap-directory links-directory + #:store store) + (catch 'system-error + (lambda () + (link path link-file)) + (lambda args + (let ((errno (system-error-errno args))) + (cond ((= errno EEXIST) + ;; Someone else put an entry for PATH in + ;; LINKS-DIRECTORY before we could. Let's use it. + (replace-with-link path link-file + #:swap-directory + links-directory + #:store store)) + ((= errno ENOSPC) + ;; There's not enough room in the directory index for + ;; more entries in .links, but that's fine: we can + ;; just stop. + #f) + ((= errno EMLINK) + ;; PATH has reached the maximum number of links, but + ;; that's OK: we just can't deduplicate it more. + #f) + (else (apply throw args))))))))))) |