snapshot: Issue with other processes accessing the mounted brick

Added code for unmount of activated snapshot brick during snapshot
deactivation process which make sense as mount point for deactivated
bricks should not exist.

Removed code for mounting newly created snapshot, as newly created
snapshots should not mount until it is activated.

Added code for mount point creation and snapshot mount during snapshot
activation.

Added validation during glusterd init for mounting only those snapshot
whose status is either STARTED or RESTORED.

During snapshot restore, mount point for stopped snap should exist as
it is required to set extended attribute.

During handshake, after getting updates from friend mount point for
activated snapshot should exist and should not for deactivated
snapshot.

While getting snap status we should show relevent information for
deactivated snapshots, after this pathch 'gluster snap status' command
will show output like-

Snap Name : snap1
Snap UUID : snap-uuid

	Brick Path        :   server1:/run/gluster/snaps/snap-vol-name/brick
	Volume Group      :   N/A (Deactivated Snapshot)
	Brick Running     :   No
	Brick PID         :   N/A
	Data Percentage   :   N/A
	LV Size           :   N/A

Fixes: #276

Change-Id: I65783488e35fac43632615ce1b8ff7b8e84834dc
BUG: 1482023
Signed-off-by: Sunny Kumar <sunkumar@redhat.com>

1 files changed, 15 insertions, 10 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-store.c b/xlators/mgmt/glusterd/src/glusterd-store.c
index 862cba4f9cc..6747c038773 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.c
+++ b/xlators/mgmt/glusterd/src/glusterd-store.c
@@ -3515,7 +3515,7 @@ out:
         return ret;
 }
 
-static int32_t
+int32_t
 glusterd_recreate_vol_brick_mounts (xlator_t  *this,
                                     glusterd_volinfo_t *volinfo)
 {
@@ -4521,17 +4521,22 @@ glusterd_recreate_all_snap_brick_mounts (xlator_t  *this)
                 }
         }
 
-        /* Recreate bricks of snapshot volumes */
+        /* Recreate bricks of snapshot volumes
+         * We are not creating brick mounts for stopped snaps.
+         */
         cds_list_for_each_entry (snap, &priv->snapshots, snap_list) {
                 cds_list_for_each_entry (volinfo, &snap->volumes, vol_list) {
-                        ret = glusterd_recreate_vol_brick_mounts (this,
-                                                                  volinfo);
-                        if (ret) {
-                                gf_msg (this->name, GF_LOG_ERROR, 0,
-                                        GD_MSG_BRK_MNT_RECREATE_FAIL,
-                                        "Failed to recreate brick mounts "
-                                        "for %s", snap->snapname);
-                                goto out;
+                        if (volinfo->status != GLUSTERD_STATUS_STOPPED) {
+                                ret = glusterd_recreate_vol_brick_mounts
+                                                           (this, volinfo);
+                                if (ret) {
+                                        gf_msg (this->name, GF_LOG_ERROR, 0,
+                                                GD_MSG_BRK_MNT_RECREATE_FAIL,
+                                                "Failed to recreate brick "
+                                                "mounts for %s",
+                                                snap->snapname);
+                                        goto out;
+                                }
                         }
                 }
         }