cluster/dht : Ftruncate on migrating file fails with EINVAL

What:
If dht_open is called on a migrating file after the inode_ctx is set,
subsequent FOPs on that fd do not open the fd on the dst subvol.
This is seen when the open-ftruncate-close sequence is repeatedly
called on a migrating file.
A second call to the sequence described above causes dht_truncate_cbk
to call dht_truncate2 as the dht_inode_ctx was already set by the first
call. As dht_rebalance_in_progress_check is not called, the fd is not
opened on the dst subvol.
On a distributed-replicate volume, this causes AFR to
open the fd using afr_fix_open, but with the wrong flags, causing
posix_ftruncate to fail with EINVAL.
The fix: We require fd specific information to make a decision while
handling migrating files.
Set the fd_ctx to indicate the fd has been opened on the dst subvol
and check if it has been set while processing Phase1/Phase2 checks
in the FOP callback functions.

> Change-Id: I43cdcd8017b4a11e18afdd210469de7cd9a5ef14
> Signed-off-by: N Balachandran <nbalacha@redhat.com>
> Reviewed-on: http://review.gluster.org/12985
> Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
> Tested-by: Gluster Build System <jenkins@build.gluster.com>
> Reviewed-by: Dan Lambright <dlambrig@redhat.com>
> Tested-by: Dan Lambright <dlambrig@redhat.com>

Change-Id: I99f8aceec105f16631def06a263f0561954d14b3
BUG: 1293827
Signed-off-by: N Balachandran <nbalacha@redhat.com>
Reviewed-on: http://review.gluster.org/13071
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/xlators/cluster/dht/src/dht-common.c b/xlators/cluster/dht/src/dht-common.c
index d478b058b91..22c3edd15aa 100644
--- a/xlators/cluster/dht/src/dht-common.c
+++ b/xlators/cluster/dht/src/dht-common.c
@@ -8124,3 +8124,17 @@ int32_t dht_set_local_rebalance (xlator_t *this, dht_local_t *local,
         return 0;
 }
 
+gf_boolean_t
+dht_is_tier_xlator (xlator_t *this)
+{
+
+        if (strcmp (this->type, "cluster/tier") == 0)
+                return _gf_true;
+        return _gf_false;
+}
+
+int32_t
+dht_release (xlator_t *this, fd_t *fd)
+{
+        return dht_fd_ctx_destroy (this, fd);
+}