Re: [PATCH] Support for secure erase functionality

[Johannes Thumshirn <jthumshirn@suse.de>]

On Wed, Sep 13, 2017 at 05:37:53PM +0200, Philipp Guendisch wrote:
> This patch adds a software based secure erase option to improve data
> confidentiality. The CONFIG_BLK_DEV_SECURE_ERASE option enables a mount
> flag called 'sw_secure_erase'. When you mount a volume with this flag,
> every discard call is prepended by an explicit write command to overwrite
> the data before it is discarded. A volume without a discard compatibility
> can be used as well but the discard calls will be enabled for this device
> and suppressed after the write call is made.

How can this work with CoW filesystems?

> 
> Built against torvalds/linux

This should go below the '---' so git am doesn't write it into the changelog.


[...]

> +	if (strcmp(fs_type->name, "ext4") != 0 &&
> +	    strcmp(fs_type->name, "btrfs") != 0 &&
> +	    strcmp(fs_type->name, "gfs2") != 0 &&
> +	    strcmp(fs_type->name, "gfs2meta") != 0 &&
> +	    strcmp(fs_type->name, "xfs") != 0 &&
> +	    strcmp(fs_type->name, "jfs") != 0) {
> +		pr_warn("fs: The mounted %s filesystem on drive %s does not generate discards, secure erase won't work",
> +				fs_type->name, dev_name);
> +	}
> +skip:
> +#endif

Which filesystems commonly used in production are left afterwards?

I'm sorry, but while I get that this sounds like a nice feature for a paper or
reasearch project, I don't see why it should be used on production systems at
all.

Byte,
	Johannes
-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850