afr: Fix the EIO that can occur in afr_inode_refresh as a result

     of cache invalidation(upcall).

Issue:
------
When a cache invalidation is recieved as a result of changing
pending xattr, the read_subvol is reset. Consider the below chain
of execution:

CHILD_DOWN
...
afr_readv
...
afr_inode_refresh
...
afr_inode_read_subvol_reset <- as a result of pending xattr set by
                               some other client GF_EVENT_UPCALL will
                               be sent
afr_refresh_done -> this results in an EIO, as the read subvol was
                    reset by the end of the afr_inode_refresh

Solution:
---------
When GF_EVENT_UPCALL is recieved, instead of resetting read_subvol,
set a variable need_refresh in inode_ctx, the next time some one
starts a txn, along with event gen, need_rrefresh also needs to
be checked.

Change-Id: Ifda21a7a8039b8874215e1afa4bdf20f7d991b58
BUG: 1396952
Signed-off-by: Poornima G <pgurusid@redhat.com>
Reviewed-on: http://review.gluster.org/15892
Reviewed-by: Ravishankar N <ravishankar@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/xlators/cluster/afr/src/afr-transaction.c b/xlators/cluster/afr/src/afr-transaction.c
index e6878eb35ff..eb7571db5f1 100644
--- a/xlators/cluster/afr/src/afr-transaction.c
+++ b/xlators/cluster/afr/src/afr-transaction.c
@@ -2573,7 +2573,9 @@ afr_transaction (call_frame_t *frame, xlator_t *this, afr_transaction_type type)
 
         ret = afr_inode_get_readable (frame, local->inode, this,
                                       local->readable, &event_generation, type);
-        if (ret < 0 || event_generation != priv->event_generation) {
+        if (ret < 0 || afr_is_inode_refresh_reqd (local->inode, this,
+                                                  priv->event_generation,
+                                                  event_generation)) {
                 afr_inode_refresh (frame, this, local->inode, local->loc.gfid,
                                    afr_write_txn_refresh_done);
         } else {