glusterd/snapshot : Provide enable/disable option for snapshot auto-delete feature.

This patch provides an interface to enable or disable
the auto-delete feature.
Syntax : gluster snapshot config auto-delete <enable/disable>

DETAILS :

1) When auto-delete feature is disabled, If the the soft-limit is
reached then user is given a warning about exceeding soft-limit
along with successful snapshot creation message (oldest snapshot is
not deleted). And upon reaching hard-limit further snapshot creation
is not allowed.

Example :
------------------------------------------------------------------
|Case - 1: Upon reaching soft-limit
|
|Snapshot create : snap successfully created.
|Warning : soft-limit of volume (vol) is reached. Snapshot creation
|is not possible once hard-limit is reached.
|
|-----------------------------------------------------
|Case - 2: Upon reaching hard-limit
|
|Snapshot create : snap creation failed.
|Error : hard-limit of volume (vol) is reached, Hence it is not
|possible to take further snapshots. Please delete few snapshots
|of the volume (vol) before taking another snapshot.
------------------------------------------------------------------

2) When auto-delete feature is enabled, then as soon as the soft-limit
is reached the oldest snapshot is deleted for every successful snapshot
creation (same as existing method), With this it is made sure that
number of snapshot created is not more than snap-max-hard-limit.

Change-Id: Ie3ca64bbd2c763371f541cd2e378314e73b695b4
BUG: 1105415
Signed-off-by: Sachin Pandit <spandit@redhat.com>
Reviewed-on: http://review.gluster.org/8017
Tested-by: Justin Clift <justin@gluster.org>
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Raghavendra Bhat <raghavendra@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-store.h b/xlators/mgmt/glusterd/src/glusterd-store.h
index dd5c6ec0dd7..ba3662bc7b2 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.h
+++ b/xlators/mgmt/glusterd/src/glusterd-store.h
@@ -69,6 +69,7 @@ typedef enum glusterd_store_ver_ac_{
 #define GLUSTERD_STORE_KEY_SNAP_STATUS          "status"
 #define GLUSTERD_STORE_KEY_SNAP_RESTORED        "snap-restored"
 #define GLUSTERD_STORE_KEY_SNAP_MAX_HARD_LIMIT  "snap-max-hard-limit"
+#define GLUSTERD_STORE_KEY_SNAP_AUTO_DELETE     "auto-delete"
 #define GLUSTERD_STORE_KEY_SNAP_MAX_SOFT_LIMIT  "snap-max-soft-limit"
 
 #define GLUSTERD_STORE_KEY_BRICK_HOSTNAME       "hostname"