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

[Daniel Henrique Barboza]

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: yilzh...@redhat.com
Cc: Jose Ricardo Ziviani <jos...@linux.vnet.ibm.com>
Signed-off-by: Yasmin Beatriz <yasm...@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;
      }