cluster/dht: Check for open fd only on EBADF

DHT fd based fops used to check if the fd was open
on the cached subvol before winding the call. However,
this introduced a performance regression of about
30% for reads.

This check was introduced to handle cases where files
were migrated while IOs were happening. As this is not
the common case, dht will now check if the fd is
open on the cached subvol only if the call fails
with EBADF.

This will prevent a performance hit where a rebalance
is not running.

Change-Id: I2035a858d63c3fcd22bb634055bbb0ad01686808
BUG: 1476665
Signed-off-by: N Balachandran <nbalacha@redhat.com>
Reviewed-on: https://review.gluster.org/17976
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Susant Palai <spalai@redhat.com>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index 7a53bc60c6b..bb9865cab58 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -1089,8 +1089,10 @@ posix_zerofill(call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset,
 
         ret = posix_do_zerofill (frame, this, fd, offset, len,
                                  &statpre, &statpost, xdata);
-        if (ret < 0)
+        if (ret < 0) {
+                op_errno = -ret;
                 goto out;
+        }
 
         STACK_UNWIND_STRICT(zerofill, frame, 0, 0, &statpre, &statpost, NULL);
         return 0;