mgmt/glusterd: use proper path to the volfile

Till now, glusterd was generating the volfile path for the snapshot
volume's bricks like this.

/snaps/<snap name>/<brick volfile>

But in reality, the path to the brick volfile for a snapshot volume is

/snaps/<snap name>/<snap volume name>/<brick volfile>

The above workaround was used to distinguish between a mount command used
to mount the snapshot volume, and a brick of the snapshot volume, so that
based on what is actually happening, glusterd can return the proper volfile
(client volfile for the former and the brick volfile for the latter). But,
this was causing problems for snapshot restore when brick multiplexing is
enabled. Because, with brick multiplexing, it tries to find the volfile
and sends GETSPEC rpc call to glusterd using the 2nd style of path i.e.

/snaps/<snap name>/<snap volume name>/<brick volfile>

So, when the snapshot brick (which is multiplexed) sends a GETSPEC rpc
request to glusterd for obtaining the brick volume file, glusterd was
returning the client volume file of the snapshot volume instead of the
brick volume file.

Change-Id: I28b2dfa5d9b379fe943db92c2fdfea879a6a594e
fixes: bz#1636218
Signed-off-by: Raghavendra Bhat <raghavendra@redhat.com>

3 files changed, 26 insertions, 8 deletions

diff --git a/xlators/features/snapview-server/src/snapview-server-helpers.c b/xlators/features/snapview-server/src/snapview-server-helpers.c
index 6f305dbc2fb..e7025b70cc6 100644
--- a/xlators/features/snapview-server/src/snapview-server-helpers.c
+++ b/xlators/features/snapview-server/src/snapview-server-helpers.c
@@ -461,8 +461,9 @@ __svs_initialise_snapshot_volume (xlator_t *this, const char *name,
                 goto out;
         }
 
-        snprintf (volname, sizeof (volname), "/snaps/%s/%s",
-                  dirent->name, dirent->snap_volname);
+        snprintf (volname, sizeof (volname), "/snaps/%s/%s/%s",
+                  dirent->name, dirent->snap_volname,
+                  dirent->snap_volname);
 
 
         fs = glfs_new (volname);
diff --git a/xlators/mgmt/glusterd/src/glusterd-handshake.c b/xlators/mgmt/glusterd/src/glusterd-handshake.c
index 84dd077af73..7cc5e98814f 100644
--- a/xlators/mgmt/glusterd/src/glusterd-handshake.c
+++ b/xlators/mgmt/glusterd/src/glusterd-handshake.c
@@ -53,6 +53,7 @@ get_snap_volname_and_volinfo (const char *volpath, char **volname,
         char            *vol            = NULL;
         glusterd_snap_t *snap           = NULL;
         xlator_t        *this           = NULL;
+        char            *volfile_token  = NULL;
 
         this = THIS;
         GF_ASSERT (this);
@@ -102,12 +103,27 @@ get_snap_volname_and_volinfo (const char *volpath, char **volname,
          */
         ret = glusterd_volinfo_find (volname_token, volinfo);
         if (ret) {
-                *volname = gf_strdup (volname_token);
+                gf_msg (this->name, GF_LOG_WARNING, 0, GD_MSG_VOLINFO_GET_FAIL,
+                        "failed to get the volinfo for the volume %s",
+                        volname_token);
+
+                /* Get the actual volfile name */
+                volfile_token = strtok_r (NULL, "/", &save_ptr);
+                *volname = gf_strdup (volfile_token);
                 if (NULL == *volname) {
                         ret = -1;
                         goto out;
                 }
 
+                        /*
+                         * Ideally, this should succeed as volname_token now
+                         * contains the name of the snap volume (i.e. name of
+                         * the volume that represents the snapshot).
+                         * But, if for some reason, volinfo for the snap volume
+                         * is not found, then try to get from the name of the
+                         * volfile. Name of the volfile is like this.
+                         * <snap volume name>.<hostname>.<brick path>.vol
+                         */
                 ret = glusterd_snap_volinfo_find (volname_token, snap,
                                                   volinfo);
                 if (ret) {
@@ -116,7 +132,7 @@ get_snap_volname_and_volinfo (const char *volpath, char **volname,
                         if (!vol) {
                                 gf_msg (this->name, GF_LOG_ERROR, EINVAL,
                                         GD_MSG_INVALID_ENTRY, "Invalid "
-                                                "volname (%s)", volname_token);
+                                                "volname (%s)", volfile_token);
                                 goto out;
                         }
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-utils.c b/xlators/mgmt/glusterd/src/glusterd-utils.c
index a1fd62da078..30288e32fe6 100644
--- a/xlators/mgmt/glusterd/src/glusterd-utils.c
+++ b/xlators/mgmt/glusterd/src/glusterd-utils.c
@@ -2067,10 +2067,10 @@ retry:
         }
 
         if (volinfo->is_snap_volume) {
-                snprintf (volfile, PATH_MAX,"/%s/%s/%s.%s.%s",
+                snprintf (volfile, PATH_MAX, "/%s/%s/%s/%s.%s.%s",
                           GLUSTERD_VOL_SNAP_DIR_PREFIX,
                           volinfo->snapshot->snapname, volinfo->volname,
-                          brickinfo->hostname, exp_path);
+                          volinfo->volname, brickinfo->hostname, exp_path);
         } else {
                 snprintf (volfile, PATH_MAX, "%s.%s.%s", volinfo->volname,
                           brickinfo->hostname, exp_path);
@@ -5552,10 +5552,11 @@ attach_brick (xlator_t *this,
         GLUSTERD_GET_BRICK_PIDFILE (pidfile2, volinfo, brickinfo, conf);
 
         if (volinfo->is_snap_volume) {
-                snprintf (full_id, sizeof(full_id), "/%s/%s/%s.%s.%s",
+                snprintf (full_id, sizeof(full_id), "/%s/%s/%s/%s.%s.%s",
                           GLUSTERD_VOL_SNAP_DIR_PREFIX,
                           volinfo->snapshot->snapname,
-                          volinfo->volname, brickinfo->hostname, unslashed);
+                          volinfo->volname, volinfo->volname,
+                          brickinfo->hostname, unslashed);
         } else {
                 snprintf (full_id, sizeof(full_id), "%s.%s.%s",
                           volinfo->volname, brickinfo->hostname, unslashed);