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Merge pull request #11863 from poettering/subvol-no-submount

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nspawn: don't descend into subvols on --ephemeral
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2019-03-01 16:44:40 +01:00
committed by GitHub
parent cc5fc36aec 3f2fa83499
commit 672d1f57f7
2 changed files with 20 additions and 16 deletions
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man/systemd-nspawn.xml
+19 -15
View File
@@ -160,16 +160,18 @@
<varlistentry>
<term><option>--template=</option></term>
<listitem><para>Directory or <literal>btrfs</literal> subvolume to use as template for the container's root
directory. If this is specified and the container's root directory (as configured by
<option>--directory=</option>) does not yet exist it is created as <literal>btrfs</literal> snapshot (if
supported) or plain directory (otherwise) and populated from this template tree. Ideally, the specified
template path refers to the root of a <literal>btrfs</literal> subvolume, in which case a simple copy-on-write
snapshot is taken, and populating the root directory is instant. If the specified template path does not refer
to the root of a <literal>btrfs</literal> subvolume (or not even to a <literal>btrfs</literal> file system at
all), the tree is copied (though possibly in a 'reflink' copy-on-write scheme — if the file system supports
that), which can be substantially more time-consuming. May not be specified together with
<option>--image=</option> or <option>--ephemeral</option>.</para>
<listitem><para>Directory or <literal>btrfs</literal> subvolume to use as template for the
container's root directory. If this is specified and the container's root directory (as configured by
<option>--directory=</option>) does not yet exist it is created as <literal>btrfs</literal> snapshot
(if supported) or plain directory (otherwise) and populated from this template tree. Ideally, the
specified template path refers to the root of a <literal>btrfs</literal> subvolume, in which case a
simple copy-on-write snapshot is taken, and populating the root directory is instant. If the
specified template path does not refer to the root of a <literal>btrfs</literal> subvolume (or not
even to a <literal>btrfs</literal> file system at all), the tree is copied (though possibly in a
'reflink' copy-on-write scheme — if the file system supports that), which can be substantially more
time-consuming. Note that the snapshot taken is of the specified directory or subvolume, including
all subdirectories and subvolumes below it, but excluding any sub-mounts. May not be specified
together with <option>--image=</option> or <option>--ephemeral</option>.</para>
<para>Note that this switch leaves host name, machine ID and
all other settings that could identify the instance
@@ -183,11 +185,13 @@
<listitem><para>If specified, the container is run with a temporary snapshot of its file system that is removed
immediately when the container terminates. May not be specified together with
<option>--template=</option>.</para>
<para>Note that this switch leaves host name, machine ID and all other settings that could identify the
instance unmodified. Please note that — as with <option>--template=</option> — taking the temporary snapshot is
more efficient on file systems that support subvolume snapshots or 'reflinks' naively (<literal>btrfs</literal>
or new <literal>xfs</literal>) than on more traditional file systems that do not
(<literal>ext4</literal>).</para>
<para>Note that this switch leaves host name, machine ID and all other settings that could identify
the instance unmodified. Please note that — as with <option>--template=</option> — taking the
temporary snapshot is more efficient on file systems that support subvolume snapshots or 'reflinks'
natively (<literal>btrfs</literal> or new <literal>xfs</literal>) than on more traditional file
systems that do not (<literal>ext4</literal>). Note that the snapshot taken is of the specified
directory or subvolume, including all subdirectories and subvolumes below it, but excluding any
sub-mounts.</para>
<para>With this option no modifications of the container image are retained. Use
<option>--volatile=</option> (described below) for other mechanisms to restrict persistency of
src/basic/btrfs-util.c
+1 -1
View File
@@ -1628,7 +1628,7 @@ int btrfs_subvol_snapshot_fd_full(
} else if (r < 0)
return r;
r = copy_directory_fd_full(old_fd, new_path, COPY_MERGE|COPY_REFLINK, progress_path, progress_bytes, userdata);
r = copy_directory_fd_full(old_fd, new_path, COPY_MERGE|COPY_REFLINK|COPY_SAME_MOUNT, progress_path, progress_bytes, userdata);
if (r < 0)
goto fallback_fail;