On modern file-systems (BTRFS, ZFS) it is possible to copy a file using
copy-on-write method. For large files it has the advantage of being
much faster and saving disk space (since identical extents are not
duplicated). This feature is stable and for example coreutils' `cp'
does use it automatically (see --reflink).
This commit adds support for this feature into our copy-file procedure.
Same as `cp', it defaults to 'auto, meaning the copy-on-write is
attempted, and in case of failure the regular copy is performed.
No tests are provided, because the behavior depends on the system,
underlying file-system and its configuration. That makes it challenging
to write a test for it. Manual testing was performed instead:
$ btrfs filesystem du /tmp/cow*
Total Exclusive Set shared Filename
36.00KiB 36.00KiB 0.00B /tmp/cow
$ cat cow-test.scm
(copy-file "/tmp/cow" "/tmp/cow-unspecified")
(copy-file "/tmp/cow" "/tmp/cow-always" #:copy-on-write 'always)
(copy-file "/tmp/cow" "/tmp/cow-auto" #:copy-on-write 'auto)
(copy-file "/tmp/cow" "/tmp/cow-never" #:copy-on-write 'never)
(copy-file "/tmp/cow" "/dev/shm/cow-unspecified")
(copy-file "/tmp/cow" "/dev/shm/cow-auto" #:copy-on-write 'auto)
(copy-file "/tmp/cow" "/dev/shm/cow-never" #:copy-on-write 'never)
$ ./meta/guile -s cow-test.scm
$ btrfs filesystem du /tmp/cow*
Total Exclusive Set shared Filename
36.00KiB 0.00B 36.00KiB /tmp/cow
36.00KiB 0.00B 36.00KiB /tmp/cow-always
36.00KiB 0.00B 36.00KiB /tmp/cow-auto
36.00KiB 36.00KiB 0.00B /tmp/cow-never
36.00KiB 0.00B 36.00KiB /tmp/cow-unspecified
$ sha1sum /tmp/cow* /dev/shm/cow*
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /tmp/cow
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /tmp/cow-always
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /tmp/cow-auto
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /tmp/cow-never
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /tmp/cow-unspecified
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /dev/shm/cow-auto
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /dev/shm/cow-never
4c665f87b5dc2e7d26279c4b48968d085e1ace32 /dev/shm/cow-unspecified
This commit also adds to new failure modes for (copy-file).
Failure to copy-on-write when 'always was passed in:
scheme@(guile-user)> (copy-file "/tmp/cow" "/dev/shm/cow" #:copy-on-write 'always)
ice-9/boot-9.scm:1676:22: In procedure raise-exception:
In procedure copy-file: copy-on-write failed: Invalid cross-device link
Passing in invalid value for the #:copy-on-write keyword argument:
scheme@(guile-user)> (copy-file "/tmp/cow" "/dev/shm/cow" #:copy-on-write 'nevr)
ice-9/boot-9.scm:1676:22: In procedure raise-exception:
In procedure copy-file: invalid value for #:copy-on-write: nevr
* NEWS: Add note for copy-file supporting copy-on-write.
* configure.ac: Check for linux/fs.h.
* doc/ref/posix.texi (File System)[copy-file]: Document the new
signature.
* libguile/filesys.c (clone_file): New function cloning a file using
FICLONE, if supported.
(k_copy_on_write): New keyword.
(sym_always, sym_auto, sym_never): New symbols.
(scm_copy_file2): Renamed from scm_copy_file. New #:copy-on-write
keyword argument. Attempt copy-on-write copy by default.
(scm_copy_file): Call scm_copy_file2.
* libguile/filesys.h: Add scm_copy_file2 as SCM_INTERNAL.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
* module/rnrs/bytevectors/gnu.scm: New file.
* am/bootstrap.am (SOURCES): Add it.
* libguile/bytevectors.c (scm_bytevector_slice): New function.
* libguile/bytevectors.h (scm_bytevector_slice): New declaration.
* test-suite/tests/bytevectors.test ("bytevector-slice"): New tests.
* doc/ref/api-data.texi (Bytevector Slices): New node.
* configure.ac: Check for ‘fchdir’.
* libguile/filesys.c
(scm_chdir): Support file ports.
(scm_init_filesys): Report support of file ports.
* doc/ref/posix.texi (Processes): Update accordingly.
* doc/ref/guile.texi: Add copyright line for new documentation in this
patch and later patches.
* test-suite/tests/filesys.test ("chdir"): Test it.
Signed-off-by: Ludovic Courtès <ludo@gnu.org>
* NEWS: Update.
* am/bootstrap.am (SOURCES):
* module/Makefile.am (SOURCES): Add system/foreign-library.scm.
* configure.ac: Replace ltdl check with -ldl check.
* libguile/dynl.c: Rewrite to just expose core dlopen / dlsym / etc to a
helper Scheme module.
(scm_dynamic_link, scm_dynamic_pointer, scm_dynamic_function)
(scm_dynamic_object_p, scm_dynamic_call): Rewrite in terms of (system
foreign-library).
* libguile/extensions.c (load_extension): Avoid scm_dynamic_call.
* module/system/foreign-library.scm: New file.
* module/oop/goops.scm (<dynamic-object>): Hackily export
<foreign-library> instead of a class here.
* doc/ref/api-foreign.texi (Foreign Function Interface): Rewrite to only
document the new interfaces. Eventually we will deprecate
dynamic-link and friends.
* doc/ref/guile.texi (API Reference): Move Foreign Objects after Foreign
Function Interface. Seems there should be some closer relationship
but this will do for now.
* doc/ref/tour.texi (Putting Extensions into Modules):
* doc/ref/libguile-parallel.texi (Parallel Installations): Update for
rename of Modules and Extensions to Foreign Extensions.
* libguile/deprecated.h:
* libguile/deprecated.c (scm_dynamic_unlink): Deprecate.
* libguile/guile.c: Remove ltdl include.
* test-suite/tests/foreign.test: Update tests to use new API, and update
error expectations.
* doc/ref/api-debug.texi (VM Hooks): Update for changes in VM hook API.
* doc/ref/guile.texi: Update copyright years.
* doc/ref/preface.texi (Contributors): Update.
* module/ice-9/command-line.scm (version-etc): Change #:copyright-year
to 2018.
* doc/ref/guile.texi: Add 2017 and 2018 to the copyright years.
* configure.ac (GUILE_CONFIGURE_COPYRIGHT): Add 2018.
* doc/ref/api-compound.texi: Remove.
* doc/ref/api-data.texi: Fold "Compound Data Types" and "Simple Data
Types" into just "Data Types". The distinction didn't work.
* doc/ref/guile.texi:
* doc/ref/Makefile.am:
* doc/ref/srfi-modules.texi: Adapt.
* doc/ref/guile.texi: Add 2016 to user-visible copyright notice.
* module/ice-9/command-line.scm (version-etc): Bump 'copyright-year' to
2016.
* module/system/repl/common.scm (*version*): Add 2016 to the range of
copyright years.
* doc/ref/api-memory.texi (Memory Blocks): Recommend against
scm_gc_free. Refer to foreign objects instead of smobs. Remove
discussion of scm_must_malloc et al.
* doc/ref/guile.texi (API Reference): Rename SMOB menu item.
* doc/ref/libguile-snarf.texi (Function Snarfing): Update example to not
refer to smobs.
* doc/ref/tools.texi (How guile-snarf works): Likewise.
* doc/ref/libguile-smobs.texi: Remove; this tutorial is superseded by
libguile-foreign-objects.
* doc/ref/libguile-foreign-objects.texi: Proofreading.
* doc/ref/libguile-program.texi: Update Dia examples to refer to foreign
objects.
* doc/ref/libguile-concepts.texi (Garbage Collection): Update to
accurately describe the BDW-GC, and to avoid reference to mark
functions.
* doc/ref/guile.texi: Remove libguile-smobs, and reword API menu.
* doc/ref/api-utility.texi (Equality): Mention GOOPS instead of SMOBs.
* doc/ref/api-smobs.texi (Smobs): Describe as a legacy interface.
Exhort readers against the writing of mark functions.
* doc/ref/api-foreign-objects.texi (Foreign Objects): Proofreading.
* doc/ref/api-control.texi (Catch): Fix ref to point to foreign
objects.
* doc/ref/Makefile.am: Remove libguile-smobs.texi.
* doc/ref/api-foreign-objects.texi:
* doc/ref/libguile-foreign-objects.texi: New files.
* doc/ref/guile.texi:
* doc/ref/Makefile.am: Link new files into docs.
* doc/ref/guile.texi: Add 2014 to list of copyright years in @copying
section.
* module/ice-9/command-line.scm (version-etc): Bump 'copyright-year' to
2014.
* module/system/repl/common.scm (*version*): Add 2014 to the range of
copyright years.
* doc/ref/statprof.texi:
* doc/ref/sxml.texi:
* doc/ref/texinfo.texi: New files, containing the documentation that was
previously generated from source and rendered into
standard-library.texi. The documentation is still horrible, but at
least now it is user-editable.
* doc/ref/Makefile.am (guile_TEXINFOS): Add curried.texi to list
* doc/ref/curried.texi: New file.
* doc/ref/guile.texi (Guile Modules): Add "Curried Definitions" to menu.
* doc/ref/scheme-ideas.texi (Lambda Alternatives): Refer to "Curried Definitions"
from the `define' section.
* doc/ref/scheme-using.texi (Installing Site Packages): Add a new
section about where to install .scm, .go, and .so files.
* doc/ref/tour.texi: Reference it here.
* doc/ref/guile.texi: Add new section.
* doc/ref/libguile-parallel.texi: New file, documenting parallel
installation and the use of pkg-config.
* doc/ref/libguile-linking.texi: Adapt.
* doc/ref/libguile-autoconf.texi: Rename from autoconf.texi. Lower
sections, and integrate in the "Programming in C" chapter.
* doc/ref/guile.texi: Adapt.
* doc/ref/guile.texi (Programming in Scheme):
* doc/ref/scheme-scripts.texi (Guile Scripting): Moved "Invoking Guile"
to its own file.
* doc/ref/guile-invoke.texi (Invoking Guile): Initial revision. This
file contains the former section "Invoking Guile" that was included in
the chapter "Programming in Scheme" as a subsection named
"Command-line Options." It also includes a new subsection "Environment
Variables," which describes those variables that can be set in the
operating system before Guile is started and which affect Guile's
run-time behavior.
* doc/ref/web.texi: New file, here to document the various (web ...)
modules. Quite a rough beginning, but it is a start...
* doc/ref/guile.texi:
* doc/ref/Makefile.am: Add to manual.
Because that probably isn't where people will look for it.
Thanks to Noah Lavine for the idea.
* doc/ref/api-regex.texi (Regular Expressions): New file, containing
the regex doc (promoted one level) that used to be in api-data.texi.
* doc/ref/guile.texi (API Reference): Include new file, and add menu
entry for the new section.
* THANKS: Add Noah.
* doc/ref/Makefile.am:
* doc/ref/guile.texi:
* doc/ref/scheme-debugging.texi: Remove scheme-debugging.texi, which
only described tracing. Tracing documentation is now in
api-debugging.
* doc/ref/scheme-using.texi (Evaluating Scheme Code): Remove reference
to source traps, as that section is going away.
* doc/ref/api-modules.texi (Included Guile Modules): Remove reference to
Tracing. This section is a little silly, anyway...
* doc/ref/api-evaluation.texi (VM Behaviour): Remove section, it is in
api-debugging now.
* doc/ref/api-debug.texi (Stacks, Frames): Rename sections from
"Examining the Stack" and "Examining Stack Frames", respectively.
(Traps): Update for current API. A big and not-quite-finished update.
* README: Remove docs on "discouraged".
* configure.ac: Remove one more "discouraged" thing.
* doc/ref/api-deprecated.texi: Rename from api-discdepr.texi, and remove
sections on "discouraged".
* doc/ref/Makefile.am:
* doc/ref/guile.texi: Update referrers.
* doc/ref/r6rs.texi (R6RS Support): Skeleton of docs on our R6RS
support.
* doc/ref/guile.texi:
* doc/ref/Makefile.am: Add r6rs.texi.
* doc/ref/intro.texi: Add a link to r6rs.texi.
* doc/ref/fdl.texi: Upgrade to GFDLv1.3.
* doc/ref/guile.texi: Change copying notice to "Version 1.3 or any later
version".
(GNU Free Documentation License): New node, formerly in `fdl.texi'.
* doc/ref/guile.texi (Top): Remove @raisesections and @lowersections
around scheme-ideas.texi.
* doc/ref/scheme-ideas.texi (About Data, ...): Instead remove one
"sub" from every node here apart from the chapter node.
* doc/ref/scheme-ideas.texi (Evaluating, Eval Variable, Eval
Procedure, Eval Special, Lexical Scope, Scoping Example): Turn
subheadings back into subsubsections, and reinstate corresponding
menus. (These had to become headings, rather than (sub)*sections, when
the top level item in scheme-ideas.texi was a section. Now it's a
chapter again, they can go back to being (sub)*sections.)
* doc/ref/guile.texi (Programming in Scheme): Remove "awful" and add
"as opposed to having to dive into C code", to explain what we
really mean here. Remove incorrect para about the `Hello Scheme!'
material.
* doc/ref/intro.texi (Interactive Programming): Change "allows" to "is
designed for" - sounds less accidental!
* doc/ref/scheme-ideas.texi (Hello Scheme!): Remove unnecessary
"reference", and inappropriate "randomness".
I think it's too detailed, when compared with the other Introduction
sections. It probably also refers to concepts that haven't been
mentioned yet, but are mentioned in the following quick tour chapter;
so let's move it there.
* doc/ref/guile.texi: Move @raisesections and @lowersections for
tour.texi material from here to inside tour.texi.
* doc/ref/intro.texi (Introduction): Don't mention reporting problems
in first para. Move menu item and material for `Reporting Bugs'
from here...
* doc/ref/tour.texi (Hello Guile!): ...to here. Also mention
reporting problems in the introductory para.
* doc/ref/guile.texi (Top): New top level `Hello Guile!' menu item;
include new file tour.texi.
* doc/ref/intro.texi (Introduction): Remove whirlwind tour menu item
and material from here...
* doc/ref/tour.texi: ...to new file here.
