linux-kernel - Re: [PATCH v6 2/9] fs: Create sb_same

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87ecsz69fk.fsf@mailhost.krisman.be>
Date: Mon, 25 Aug 2025 05:24:15 -0400
From: Gabriel Krisman Bertazi <gabriel@...sman.be>
To: André Almeida <andrealmeid@...lia.com>
Cc: Miklos Szeredi <miklos@...redi.hu>,  Amir Goldstein
 <amir73il@...il.com>,  Theodore Tso <tytso@....edu>,
  linux-unionfs@...r.kernel.org,  linux-kernel@...r.kernel.org,
  linux-fsdevel@...r.kernel.org,  Alexander Viro <viro@...iv.linux.org.uk>,
  Christian Brauner <brauner@...nel.org>,  Jan Kara <jack@...e.cz>,
  kernel-dev@...lia.com
Subject: Re: [PATCH v6 2/9] fs: Create sb_same_encoding() helper

André Almeida <andrealmeid@...lia.com> writes:

> For cases where a file lookup can look in different filesystems (like in
> overlayfs), both super blocks must have the same encoding and the same
> flags. To help with that, create a sb_same_encoding() function.
>
> Reviewed-by: Amir Goldstein <amir73il@...il.com>
> Signed-off-by: André Almeida <andrealmeid@...lia.com>


Reviewed-by: Gabriel Krisman Bertazi <gabriel@...sman.be>


> ---
>  include/linux/fs.h | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index a4d353a871b094b562a87ddcffe8336a26c5a3e2..7de9e1e4839a2726f4355ddf20b9babb74cc9681 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3747,6 +3747,24 @@ static inline bool sb_has_encoding(const struct super_block *sb)
>  	return !!sb_encoding(sb);
>  }
>  
> +/*
> + * Compare if two super blocks have the same encoding and flags
> + */
> +static inline bool sb_same_encoding(const struct super_block *sb1,
> +				    const struct super_block *sb2)
> +{
> +#if IS_ENABLED(CONFIG_UNICODE)
> +	if (sb1->s_encoding == sb2->s_encoding)
> +		return true;
> +
> +	return (sb1->s_encoding && sb2->s_encoding &&
> +	       (sb1->s_encoding->version == sb2->s_encoding->version) &&
> +	       (sb1->s_encoding_flags == sb2->s_encoding_flags));
> +#else
> +	return true;
> +#endif
> +}
> +
>  int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
>  		unsigned int ia_valid);
>  int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);

-- 
Gabriel Krisman Bertazi