Re: [PATCH 1/5] e4defrag: return more specific error message on ioctl failure

[Eric Sandeen <sandeen@redhat.com>]

Peng Tao wrote:
> Currently e4defrag relies on the EXT4_IOC_MOVE_EXT ioctl to perform online
> defragmentation. However, this iotcl kernel patch is not available before
> 2.6.30-rc1. e4defrag shall fail without obvious reasons on systems running
> older kernels. The patch adds more detailed error message addressing this
> issue and prompts users with the minimal kernel version that is needed to
> run e4defrag.
> 
> Signed-off-by: Peng Tao <bergwolf@gmail.com>
> ---
>  misc/e4defrag.c |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/misc/e4defrag.c b/misc/e4defrag.c
> index c25514a..f1c3008 100644
> --- a/misc/e4defrag.c
> +++ b/misc/e4defrag.c
> @@ -1553,7 +1553,11 @@ static int call_defrag(int fd, int donor_fd, const char *file,
>  			if (mode_flag & DETAIL) {
>  				printf("\n");
>  				PRINT_ERR_MSG_WITH_ERRNO(
> -						"Failed to defrag");
> +					"Failed to defrag with "
> +					"EXT4_IOC_MOVE_EXT ioctl");
> +				if (errno == ENOTTY)
> +					printf("\tAt least 2.6.31-rc1 of"
> +						" vallina kernel is required\n");

Typo here, s/b "vanilla"

-Eric

>  			} else {
>  				printf("\t[ NG ]\n");
>  			}