Fixes quota aux mount failure

The aux mount is created on the first limit/remove_limit/list command
and it remains until volume is stopped / deleted / (quota is disabled)
, where we do a lazy unmount. If the process is uncleanly terminated,
then the mount entry remains and we get (Transport disconnected) error
on subsequent attempts to run quota list/limit-usage/remove commands.

Second issue, There is also a risk of inadvertent rm -rf on the
/var/run/gluster causing data loss for the user. Ideally, /var/run is
a temp path for application use and should not cause any data loss to
persistent storage.

Solution:
1) unmount the aux mount after each use.
2) clean stale mount before mounting, if any.

One caveat with doing mount/unmount on each command is that we cannot
use same mount point for both list and limit commands.
The reason for this is that list command needs mount to be accessible
in cli after response from glusterd, So it could be unmounted by a
limit command if executed in parallel (had we used same mount point)
Hence we use separate mount points for list and limit commands.

> Reviewed-on: https://review.gluster.org/16938
> NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
> Smoke: Gluster Build System <jenkins@build.gluster.org>
> Reviewed-by: Manikandan Selvaganesh <manikandancs333@gmail.com>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
> Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
> Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
> (cherry picked from commit 2ae4b4058691b324535d802f4e6d24cce89a10e5)

Change-Id: I4f9e39da2ac2b65941399bffb6440db8a6ba59d0
BUG: 1449782
Signed-off-by: Sanoj Unnikrishnan <sunnikri@redhat.com>
Reviewed-on: https://review.gluster.org/17242
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: Raghavendra G <rgowdapp@redhat.com>

2 files changed, 32 insertions, 4 deletions

diff --git a/cli/src/cli-rpc-ops.c b/cli/src/cli-rpc-ops.c
index 602d3ff1611..07a63364ebe 100644
--- a/cli/src/cli-rpc-ops.c
+++ b/cli/src/cli-rpc-ops.c
@@ -3400,6 +3400,26 @@ out:
 }
 
 int
+gluster_remove_auxiliary_mount (char *volname)
+{
+        int       ret                = -1;
+        char      mountdir[PATH_MAX] = {0,};
+        xlator_t  *this               = NULL;
+
+        this = THIS;
+        GF_ASSERT (this);
+
+        GLUSTERD_GET_QUOTA_LIST_MOUNT_PATH (mountdir, volname, "/");
+        ret = gf_umount_lazy (this->name, mountdir, 1);
+        if (ret) {
+                gf_log("cli", GF_LOG_ERROR, "umount on %s failed, "
+                        "reason : %s", mountdir, strerror (errno));
+        }
+
+        return ret;
+}
+
+int
 gf_cli_print_limit_list_from_dict (cli_local_t *local, char *volname,
                                    dict_t *dict, char *default_sl, int count,
                                    int op_ret, int op_errno, char *op_errstr)
@@ -3447,7 +3467,7 @@ gf_cli_print_limit_list_from_dict (cli_local_t *local, char *volname,
                 ret = gf_canonicalize_path (path);
                 if (ret)
                         goto out;
-                GLUSTERD_GET_QUOTA_AUX_MOUNT_PATH (mountdir, volname, path);
+                GLUSTERD_GET_QUOTA_LIST_MOUNT_PATH (mountdir, volname, path);
                 ret = print_quota_list_from_mountdir (local, mountdir,
                                                       default_sl, path, type);
         }
@@ -3930,6 +3950,7 @@ gf_cli_quota_cbk (struct rpc_req *req, struct iovec *iov,
         }
 
 xml_output:
+
         if (global_state->mode & GLUSTER_MODE_XML) {
                 ret = cli_xml_output_str ("volQuota", NULL, rsp.op_ret,
                                           rsp.op_errno, rsp.op_errstr);
@@ -3945,6 +3966,12 @@ xml_output:
 
         ret = rsp.op_ret;
 out:
+
+        if ((type == GF_QUOTA_OPTION_TYPE_LIST)
+            || (type == GF_QUOTA_OPTION_TYPE_LIST_OBJECTS)) {
+                gluster_remove_auxiliary_mount (volname);
+        }
+
         cli_cmd_broadcast_response (ret);
         if (dict)
                 dict_unref (dict);
diff --git a/cli/src/cli.h b/cli/src/cli.h
index 8acec640c83..b59e254d44f 100644
--- a/cli/src/cli.h
+++ b/cli/src/cli.h
@@ -62,9 +62,10 @@ typedef enum {
 #define GLUSTER_MODE_WIGNORE   (1 << 3)
 
 
-#define GLUSTERD_GET_QUOTA_AUX_MOUNT_PATH(abspath, volname, path)      \
-        snprintf (abspath, sizeof (abspath)-1,                          \
-                  DEFAULT_VAR_RUN_DIRECTORY"/%s%s", volname, path);
+#define GLUSTERD_GET_QUOTA_LIST_MOUNT_PATH(abspath, volname, path) do {       \
+        snprintf (abspath, sizeof (abspath)-1,                                \
+                  DEFAULT_VAR_RUN_DIRECTORY"/%s_quota_list%s", volname, path);\
+        } while (0)
 
 struct cli_state;
 struct cli_cmd_word;