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FICLONE is the new alias for the formerly btrfs-specific ioctl; XFS has experimental patches to support it. Further, we should use copy_file_range() for the case where we're only doing a limited copy. Both NFS and XFS (with reflink enabled) understand it. Part of the reason I'm doing this is so that ostree's `/etc` merge will start using XFS reflinks. But another major reason is to take the next step after and copy this code into GLib as well, so that all of the general GLib users will benefit; e.g. Nautilus will transparently do server copy offloads with NFS home directories. See also this coreutils thread about `copy_file_range()`: <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=24399>. I don't care about file holes for our use cases, so it's fine. Other changes while I'm here: - Tweak the sendfile() case to match the newly inlined logic for cfr - Add a TEMP_FAILURE_RETRY() around the read()
libglnx is the successor to libgsystem: https://git.gnome.org/browse/libgsystem
It is for modules which depend on both GLib and Linux, intended to be used as a git submodule.
Features:
- File APIs which use
openat()like APIs, but also take aGCancellableto support dynamic cancellation - APIs also have a
GErrorparameter - High level "shutil", somewhat inspired by Python's
- A "console" API for tty output
- A backport of the GLib cleanup macros for projects which can't yet take a dependency on 2.40.
Why?
There are multiple projects which have a hard dependency on Linux and GLib, such as NetworkManager, ostree, flatpak, etc. It makes sense for them to be able to share Linux-specific APIs.
This module also contains some code taken from systemd, which has very high quality LGPLv2+ shared library code, but most of the internal shared library is private, and not namespaced.
One could also compare this project to gnulib; the salient differences there are that at least some of this module is eventually destined for inclusion in GLib.
Porting from libgsystem
For all of the filesystem access code, libglnx exposes only
fd-relative API, not GFile*. It does use GCancellable where
applicable.
For local allocation macros, you should start using the g_auto
macros from GLib. A backport is included in libglnx. There are a few
APIs not defined in GLib yet, such as glnx_fd_close.
gs_transfer_out_value is replaced by g_steal_pointer.
Contributing
Currently there is not a Bugzilla product - one may be created in the future. You can submit PRs against the Github mirror:
https://github.com/GNOME/libglnx/pulls
Or alternatively, email one of the maintainers directly.