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From:   Jeremy Bongio <bongiojp@gmail.com>
Date:   Thu, 5 Jan 2023 11:03:57 -0800
Message-ID: <CANfQU3x3yB7OYPerwun3VTz89QJaFobdudj_8vCpwfNjjSRicQ@mail.gmail.com>
Subject: Re: [e2fsprogs PATCH] tune2fs: fix setting fsuuid::fsu_len
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     linux-ext4@vger.kernel.org
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Thanks for catching that!

Reviewed-by: Jeremy Bongio <bongiojp@gmail.com>

On Wed, Jan 4, 2023 at 1:04 AM Eric Biggers <ebiggers@kernel.org> wrote:
>
> From: Eric Biggers <ebiggers@google.com>
>
> Minus does not mean equals.
>
> Besides fixing an obvious bug, this avoids the following compiler
> warning with clang -Wall:
>
> tune2fs.c:3625:20: warning: expression result unused [-Wunused-value]
>                         fsuuid->fsu_len - UUID_SIZE;
>                         ~~~~~~~~~~~~~~~ ^ ~~~~~~~~~
>
> Fixes: a83e199da0ca ("tune2fs: Add support for get/set UUID ioctls.")
> Cc: Jeremy Bongio <bongiojp@gmail.com>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>  misc/tune2fs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/misc/tune2fs.c b/misc/tune2fs.c
> index 088f87e5..7937b8b5 100644
> --- a/misc/tune2fs.c
> +++ b/misc/tune2fs.c
> @@ -3622,7 +3622,7 @@ _("Warning: The journal is dirty. You may wish to replay the journal like:\n\n"
>                 ret = -1;
>  #ifdef __linux__
>                 if (fsuuid) {
> -                       fsuuid->fsu_len - UUID_SIZE;
> +                       fsuuid->fsu_len = UUID_SIZE;
>                         fsuuid->fsu_flags = 0;
>                         memcpy(&fsuuid->fsu_uuid, new_uuid, UUID_SIZE);
>                         ret = ioctl(fd, EXT4_IOC_SETFSUUID, fsuuid);
> --
> 2.39.0
>