[Devel] [PATCH hci-8.1] ve/fs: let a container mount ext2 and ext3 through the ext4 driver

[Konstantin Khorenko]

On 10/21/26 20:03, Eva Kurchatova wrote:
> The ext4 driver also registers the ext2 and ext3 filesystem types, and
> those two carry none of the container flags ext4 itself has, so inside
> a container they are absent from /proc/filesystems and a mount of an
> ext2 or ext3 image fails with "unknown filesystem type", while the same
> image mounts as ext4. It is the same code either way, so give the two
> aliases the same flags; LTP formats its test devices as ext2 by default
> and every one of those tests breaks in a container on that mount.

i do not see any reason to enable mounting ext2/ext3 filesystems inside
Containers while we already allow ext4 mounts.

We do support ext4 inside a CT and we test it.
We do not test ext2/ext3 - why to allow it?

Until we have a proper usecase / a request from a customer, i would not enable it.

If we are talking about LTP tests, we can run currently failing tests inside a CT
with LTP_DEV_FS_TYPE=... set

> 
> https://virtuozzo.atlassian.net/browse/VSTOR-132330
> Feature: fs: whiltelist what can be mounted in a CT
> 
> Signed-off-by: Eva Kurchatova <eva.kurchatova at virtuozzo.com>
> ---
>  fs/ext4/super.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index e292c0597eaf..0f73473e2d4d 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -137,7 +137,7 @@ static struct file_system_type ext2_fs_type = {
>  	.init_fs_context	= ext4_init_fs_context,
>  	.parameters		= ext4_param_specs,
>  	.kill_sb		= ext4_kill_sb,
> -	.fs_flags		= FS_REQUIRES_DEV,
> +	.fs_flags		= FS_REQUIRES_DEV | FS_VIRTUALIZED | FS_VE_MOUNT,
>  };
>  MODULE_ALIAS_FS("ext2");
>  MODULE_ALIAS("ext2");
> @@ -153,7 +153,7 @@ static struct file_system_type ext3_fs_type = {
>  	.init_fs_context	= ext4_init_fs_context,
>  	.parameters		= ext4_param_specs,
>  	.kill_sb		= ext4_kill_sb,
> -	.fs_flags		= FS_REQUIRES_DEV,
> +	.fs_flags		= FS_REQUIRES_DEV | FS_VIRTUALIZED | FS_VE_MOUNT,
>  };
>  MODULE_ALIAS_FS("ext3");
>  MODULE_ALIAS("ext3");