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.

>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>
>Signed-off-by: Poornima G <pgurusid@redhat.com>

Change-Id: Ifda21a7a8039b8874215e1afa4bdf20f7d991b58
BUG: 1399450
Signed-off-by: Poornima G <pgurusid@redhat.com>
Reviewed-on: http://review.gluster.org/15959
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Ravishankar N <ravishankar@redhat.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

0 files changed, 0 insertions, 0 deletions