commit 2178a569be16b18f04ed854d24fd2281b6a429c5
author Eric Blake <eblake@redhat.com> Tue Apr 02 22:05:20 2019 -0500
committer Eric Blake <eblake@redhat.com> Mon Apr 08 13:36:04 2019 -0500
tree 47ab9097ed2740021cfb30a7a491211c681b4b6d
parent 2c573106279495795449b0d0373464b597dfe316

nbd/server: Fix blockstatus trace

Don't increment remaining_bytes until we know that we will actually be
including the current block status extent in the reply; otherwise, the
value traced will include a bytes value that is oversized by the
length of the next block status extent which did not get sent because
it instead ended the loop.

Fixes: fb7afc79
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190403030526.12258-2-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

nbd/server.c

diff --git a/nbd/server.c b/nbd/server.c
index 218a2aa..1b8c861 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1880,17 +1880,12 @@
 
         flags = (ret & BDRV_BLOCK_ALLOCATED ? 0 : NBD_STATE_HOLE) |
                 (ret & BDRV_BLOCK_ZERO      ? NBD_STATE_ZERO : 0);
-        offset += num;
-        remaining_bytes -= num;
 
         if (first_extent) {
             extent->flags = flags;
             extent->length = num;
             first_extent = false;
-            continue;
-        }
-
-        if (flags == extent->flags) {
+        } else if (flags == extent->flags) {
             /* extend current extent */
             extent->length += num;
         } else {
@@ -1903,6 +1898,8 @@
             extent->flags = flags;
             extent->length = num;
         }
+        offset += num;
+        remaining_bytes -= num;
     }
 
     extents_end = extent + 1;