posix: option to handle the shared bricks for statvfs()

Currently 'storage/posix' xlator has an option called option
`export-statfs-size no`, which exports zero as values for few
fields in `struct statvfs`. In a case of backend brick shared
between multiple brick processes, the values of these variables
should be `field_value / number-of-bricks-at-node`. This way,
even the issue of 'min-free-disk' etc at different layers would
also be handled properly when the statfs() sys call is made.

Fixes #241

> Reviewed-on: https://review.gluster.org/17618
> Reviewed-by: Jeff Darcy <jeff@pl.atyp.us>
> Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
> (cherry picked from commit febf5ed4848ad705a34413353559482417c61467)

Change-Id: I2e320e1fdcc819ab9173277ef3498201432c275f
Signed-off-by: Amar Tumballi <amarts@redhat.com>
Reviewed-on: https://review.gluster.org/17903
Smoke: Gluster Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Shyamsundar Ranganathan <srangana@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd.h b/xlators/mgmt/glusterd/src/glusterd.h
index b2141853db4..3226ec24c0f 100644
--- a/xlators/mgmt/glusterd/src/glusterd.h
+++ b/xlators/mgmt/glusterd/src/glusterd.h
@@ -232,6 +232,11 @@ struct glusterd_brickinfo {
          */
         uint16_t           group;
         uuid_t             jbr_uuid;
+
+        /* Below are used for handling the case of multiple bricks sharing
+           the backend filesystem */
+        uint64_t           statfs_fsid;
+        uint32_t           fs_share_count;
 };
 
 typedef struct glusterd_brickinfo glusterd_brickinfo_t;