Re: [Qemu-devel] [PATCH] dump: Show custom message for ENOSPC

[Daniel Henrique Barboza <danielhb@linux.vnet.ibm.com>]

Hi Yasmin,

On 02/09/2018 05:31 PM, Yasmin Beatriz wrote:
> This patch intends to make a more specific message for when
> the system has not enough space to save guest memory.
>
> Reported-by: yilzhang@redhat.com
> Cc: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
> Signed-off-by: Yasmin Beatriz <yasmins@linux.vnet.ibm.com>
> ---
>   dump.c | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/dump.c b/dump.c
> index e9dfed060a..eb56ff53f6 100644
> --- a/dump.c
> +++ b/dump.c
> @@ -106,6 +106,9 @@ static int fd_write_vmcore(const void *buf, size_t size, void *opaque)
>
>       written_size = qemu_write_full(s->fd, buf, size);
>       if (written_size != size) {
> +        if (errno == ENOSPC) {
> +            return -ENOSPC;
> +        }
You can do like this:


      if (written_size != size) {
+        return -errno;
+     }


Everyone is checking for a negative "ret" to see if an error occurred in 
qemu_write_full.
There is no negative errno AFAIK, so you can spare one "if" clause there 
and still
check for -ENOSPC down there.

It might be worth checking if this code can't be baked into 
qemu_write_full too.



Thanks,


Daniel

>           return -1;
>       }
>
> @@ -364,7 +367,11 @@ static void write_data(DumpState *s, void *buf, int length, Error **errp)
>
>       ret = fd_write_vmcore(buf, length, s);
>       if (ret < 0) {
> -        error_setg(errp, "dump: failed to save memory");
> +        if (ret == -ENOSPC) {
> +            error_setg(errp, "dump: not enough space to save memory");
> +        } else {
> +            error_setg(errp, "dump: failed to save memory");
> +        }
>       } else {
>           s->written_size += length;
>       }