[PATCH container/manager 0/2] make mount point attribute preservation configurable

[PATCH container/manager 0/2] make mount point attribute preservation configurable

[Filip Schauer]

The commit 0db559517ac6 (mountpoint_insert_staged: inherit attributes if
directory already exists) introduced automatic propagation of uid, gid,
and mode from the target directory to the mounted filesystem. While this
improves compatibility with some OCI images, it also caused undesired
ownership changes on some mount points.

Since attribute preservation is not always desired, make this behavior
configurable via a new "keepattrs" mountpoint flag. Default to disabled
to preserve historical behavior.

Patch 2/2 exposes this flag in the UI and depends on patch 1/2.

pve-container:

Filip Schauer (1):
  make mount point attribute preservation configurable

 src/PVE/LXC.pm            | 4 +---
 src/PVE/LXC/Config.pm     | 6 ++++++
 src/lxc-pve-prestart-hook | 2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)


pve-manager:

Filip Schauer (1):
  ui: lxc/MPEdit: add "keepattrs" flag

 www/manager6/lxc/MPEdit.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)


Summary over all repositories:
  4 files changed, 23 insertions(+), 4 deletions(-)

-- 
Generated by git-murpp 0.6.0

[PATCH container 1/2] make mount point attribute preservation configurable

[Filip Schauer]

The commit 0db559517ac6 (mountpoint_insert_staged: inherit attributes if
directory already exists) introduced automatic propagation of uid, gid,
and mode from the target directory to the mounted filesystem. While this
improves compatibility with some OCI images, it also caused undesired
ownership changes on some mount points.

Since attribute preservation is not always desired, make this behavior
configurable via a new "keepattrs" mountpoint flag. Default to disabled
to preserve historical behavior.

Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
 src/PVE/LXC.pm            | 4 +---
 src/PVE/LXC/Config.pm     | 6 ++++++
 src/lxc-pve-prestart-hook | 2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
index 41ea991..2c02e9a 100644
--- a/src/PVE/LXC.pm
+++ b/src/PVE/LXC.pm
@@ -2478,10 +2478,8 @@ sub mountpoint_hotplug : prototype($$$$$) {
         chdir('/')
             or die "failed to change root directory within the container's mount namespace: $!\n";
 
-        my $keep_attrs = $mp->{type} eq 'volume';
-
         mountpoint_insert_staged(
-            $mount_fd, undef, $mp->{mp}, $opt, $root_uid, $root_gid, $keep_attrs,
+            $mount_fd, undef, $mp->{mp}, $opt, $root_uid, $root_gid, $mp->{keepattrs},
         );
     });
 }
diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
index 6f54e9f..0090d61 100644
--- a/src/PVE/LXC/Config.pm
+++ b/src/PVE/LXC/Config.pm
@@ -987,6 +987,12 @@ my $mp_desc = {
         verbose_description => "Path to the mount point as seen from inside the container.\n\n"
             . "NOTE: Must not contain any symlinks for security reasons.",
     },
+    keepattrs => {
+        type => 'boolean',
+        description => 'Inherit attributes from the target path, if it exists already.',
+        optional => 1,
+        default => 0,
+    },
 };
 PVE::JSONSchema::register_format('pve-ct-mountpoint', $mp_desc);
 
diff --git a/src/lxc-pve-prestart-hook b/src/lxc-pve-prestart-hook
index f900c12..9862509 100755
--- a/src/lxc-pve-prestart-hook
+++ b/src/lxc-pve-prestart-hook
@@ -100,7 +100,7 @@ PVE::LXC::Tools::lxc_hook(
                 # Mount relative to the rootdir fd.
                 $dest_base_fd = $rootdir_fd;
                 $dest_dir = './' . $mountpoint->{mp};
-                $keep_attrs = $mountpoint->{type} eq 'volume';
+                $keep_attrs = $mountpoint->{keepattrs};
             } else {
                 # Assert that 'rootfs' is the first one:
                 die "foreach_mount() error\n" if $opt ne 'rootfs';
-- 
2.47.3

[PATCH manager 2/2] ui: lxc/MPEdit: add "keepattrs" flag

[Filip Schauer]

Expose the "keepattrs" flag for mount points in the UI.

Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
This depends on patch 1/2.

 www/manager6/lxc/MPEdit.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/www/manager6/lxc/MPEdit.js b/www/manager6/lxc/MPEdit.js
index f4c45876..4bba536c 100644
--- a/www/manager6/lxc/MPEdit.js
+++ b/www/manager6/lxc/MPEdit.js
@@ -47,6 +47,7 @@ Ext.define('PVE.lxc.MountPointInputPanel', {
         setMPOpt('ro', values.ro);
         setMPOpt('acl', values.acl);
         setMPOpt('replicate', values.replicate);
+        setMPOpt('keepattrs', values.keepattrs);
 
         let res = {};
         res[confid] = PVE.Parser.printLxcMountPoint(me.mp);
@@ -338,6 +339,20 @@ Ext.define('PVE.lxc.MountPointInputPanel', {
             name: 'replicate',
             fieldLabel: gettext('Skip replication'),
         },
+        {
+            xtype: 'proxmoxcheckbox',
+            name: 'keepattrs',
+            defaultValue: '0',
+            fieldLabel: gettext('Keep Attributes'),
+            autoEl: {
+                tag: 'div',
+                'data-qtip': gettext('Preserve Attributes of Target Directory'),
+            },
+            bind: {
+                hidden: '{isRoot}',
+                disabled: '{isRoot}',
+            },
+        },
     ],
 });
 
-- 
2.47.3

Re: [PATCH manager 2/2] ui: lxc/MPEdit: add "keepattrs" flag

[Fabian Grünbichler]

On February 11, 2026 12:06 pm, Filip Schauer wrote:
> Expose the "keepattrs" flag for mount points in the UI.
> 
> Signed-off-by: Filip Schauer <f.schauer@proxmox.com>

Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

> ---
> This depends on patch 1/2.
> 
>  www/manager6/lxc/MPEdit.js | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/www/manager6/lxc/MPEdit.js b/www/manager6/lxc/MPEdit.js
> index f4c45876..4bba536c 100644
> --- a/www/manager6/lxc/MPEdit.js
> +++ b/www/manager6/lxc/MPEdit.js
> @@ -47,6 +47,7 @@ Ext.define('PVE.lxc.MountPointInputPanel', {
>          setMPOpt('ro', values.ro);
>          setMPOpt('acl', values.acl);
>          setMPOpt('replicate', values.replicate);
> +        setMPOpt('keepattrs', values.keepattrs);
>  
>          let res = {};
>          res[confid] = PVE.Parser.printLxcMountPoint(me.mp);
> @@ -338,6 +339,20 @@ Ext.define('PVE.lxc.MountPointInputPanel', {
>              name: 'replicate',
>              fieldLabel: gettext('Skip replication'),
>          },
> +        {
> +            xtype: 'proxmoxcheckbox',
> +            name: 'keepattrs',
> +            defaultValue: '0',
> +            fieldLabel: gettext('Keep Attributes'),
> +            autoEl: {
> +                tag: 'div',
> +                'data-qtip': gettext('Preserve Attributes of Target Directory'),

nit: this is not a heading/label, so it should have regular casing?

> +            },
> +            bind: {
> +                hidden: '{isRoot}',
> +                disabled: '{isRoot}',
> +            },
> +        },
>      ],
>  });
>  
> -- 
> 2.47.3
> 
> 
> 
> 
> 
> 

Re: [PATCH container 1/2] make mount point attribute preservation configurable

[Fabian Grünbichler]

On February 11, 2026 12:06 pm, Filip Schauer wrote:
> The commit 0db559517ac6 (mountpoint_insert_staged: inherit attributes if
> directory already exists) introduced automatic propagation of uid, gid,
> and mode from the target directory to the mounted filesystem. While this
> improves compatibility with some OCI images, it also caused undesired
> ownership changes on some mount points.
> 
> Since attribute preservation is not always desired, make this behavior
> configurable via a new "keepattrs" mountpoint flag. Default to disabled
> to preserve historical behavior.
> 
> Signed-off-by: Filip Schauer <f.schauer@proxmox.com>

Reviewed-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

> ---
>  src/PVE/LXC.pm            | 4 +---
>  src/PVE/LXC/Config.pm     | 6 ++++++
>  src/lxc-pve-prestart-hook | 2 +-
>  3 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
> index 41ea991..2c02e9a 100644
> --- a/src/PVE/LXC.pm
> +++ b/src/PVE/LXC.pm
> @@ -2478,10 +2478,8 @@ sub mountpoint_hotplug : prototype($$$$$) {
>          chdir('/')
>              or die "failed to change root directory within the container's mount namespace: $!\n";
>  
> -        my $keep_attrs = $mp->{type} eq 'volume';
> -
>          mountpoint_insert_staged(
> -            $mount_fd, undef, $mp->{mp}, $opt, $root_uid, $root_gid, $keep_attrs,
> +            $mount_fd, undef, $mp->{mp}, $opt, $root_uid, $root_gid, $mp->{keepattrs},
>          );
>      });
>  }
> diff --git a/src/PVE/LXC/Config.pm b/src/PVE/LXC/Config.pm
> index 6f54e9f..0090d61 100644
> --- a/src/PVE/LXC/Config.pm
> +++ b/src/PVE/LXC/Config.pm
> @@ -987,6 +987,12 @@ my $mp_desc = {
>          verbose_description => "Path to the mount point as seen from inside the container.\n\n"
>              . "NOTE: Must not contain any symlinks for security reasons.",
>      },
> +    keepattrs => {
> +        type => 'boolean',
> +        description => 'Inherit attributes from the target path, if it exists already.',

nit: "target path" is not a term we've used here in the past.. the usual
term for this directory is "mountpoint". 

maybe s/target path/mountpoint directory/ here?

_maybe_ we could also spell out what "attributes" means here?

> +        optional => 1,
> +        default => 0,
> +    },
>  };
>  PVE::JSONSchema::register_format('pve-ct-mountpoint', $mp_desc);
>  
> diff --git a/src/lxc-pve-prestart-hook b/src/lxc-pve-prestart-hook
> index f900c12..9862509 100755
> --- a/src/lxc-pve-prestart-hook
> +++ b/src/lxc-pve-prestart-hook
> @@ -100,7 +100,7 @@ PVE::LXC::Tools::lxc_hook(
>                  # Mount relative to the rootdir fd.
>                  $dest_base_fd = $rootdir_fd;
>                  $dest_dir = './' . $mountpoint->{mp};
> -                $keep_attrs = $mountpoint->{type} eq 'volume';
> +                $keep_attrs = $mountpoint->{keepattrs};
>              } else {
>                  # Assert that 'rootfs' is the first one:
>                  die "foreach_mount() error\n" if $opt ne 'rootfs';
> -- 
> 2.47.3
> 
> 
> 
> 
> 
> 

Re: superseded: [PATCH container 1/2] make mount point attribute preservation configurable

[Filip Schauer]

On 11/02/2026 14:48, Fabian Grünbichler wrote:
> nit: "target path" is not a term we've used here in the past.. the usual
> term for this directory is "mountpoint".
>
> maybe s/target path/mountpoint directory/ here?
>
> _maybe_ we could also spell out what "attributes" means here?

Superseded by v2:
https://lore.proxmox.com/pve-devel/20260211144111.123837-1-f.schauer@proxmox.com