glusterd: build realpath post recreate of brick mount for snapshot

Commit a60c39d introduced a new field called real_path in brickinfo to hold the
realpath() conversion. However at restore path for all snapshots and snapshot
restored volumes the brickpath gets recreated post restoration of bricks  which
means the realpath () call will fail here for all the snapshots and cloned
volumes.

Fix is to store the realpath for snapshots and clones post recreating the brick
mounts. For normal volume it would be done during retrieving the brick details
from the store.

Change-Id: Ia34853acddb28bcb7f0f70ca85fabcf73276ef13
BUG: 1322772
Signed-off-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-on: http://review.gluster.org/13869
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.com>

2 files changed, 76 insertions, 16 deletions

diff --git a/tests/bugs/snapshot/bug-1322772-real-path-fix-for-snapshot.t b/tests/bugs/snapshot/bug-1322772-real-path-fix-for-snapshot.t
new file mode 100644
index 00000000000..68dc0bbe0f7
--- /dev/null
+++ b/tests/bugs/snapshot/bug-1322772-real-path-fix-for-snapshot.t
@@ -0,0 +1,34 @@
+#!/bin/bash
+
+. $(dirname $0)/../../volume.rc
+. $(dirname $0)/../../snapshot.rc
+. $(dirname $0)/../../include.rc
+cleanup;
+
+TEST verify_lvm_version
+TEST init_n_bricks 1
+TEST setup_lvm 1
+
+TEST glusterd
+TEST pidof glusterd
+
+TEST $CLI volume create $V0 $H0:$L1
+EXPECT 'Created' volinfo_field $V0 'Status'
+
+TEST $CLI volume start $V0
+EXPECT 'Started' volinfo_field $V0 'Status'
+
+TEST $CLI snapshot create ${V0}_snap $V0
+
+# Simulate a node reboot by unmounting the brick, snap_brick and followed by
+# deleting the brick. Now once glusterd restarts, it should be able to construct
+# and remount the snap brick
+snap_brick=`gluster snap status | grep "Brick Path" | awk -F ":"  '{print $3}'`
+
+pkill gluster
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $L1
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $snap_brick
+rm -rf $snap_brick
+
+TEST glusterd
+TEST pidof glusterd
diff --git a/xlators/mgmt/glusterd/src/glusterd-store.c b/xlators/mgmt/glusterd/src/glusterd-store.c
index 97f5147dd39..c776e4b5249 100644
--- a/xlators/mgmt/glusterd/src/glusterd-store.c
+++ b/xlators/mgmt/glusterd/src/glusterd-store.c
@@ -2385,24 +2385,34 @@ glusterd_store_retrieve_bricks (glusterd_volinfo_t *volinfo)
                        GLUSTERD_ASSIGN_BRICKID_TO_BRICKINFO (brickinfo, volinfo,
                                                              brickid++);
                 }
-                /* By now if the brick is a local brick then it will be able to
-                 * resolve which is the only thing we want now for checking
-                 * whether the brickinfo->uuid matches with MY_UUID for realpath
-                 * check. Hence do not handle error
+                /* Populate brickinfo->real_path for normal volumes, for
+                 * snapshot or snapshot restored volume this would be done post
+                 * creating the brick mounts
                  */
-                (void)glusterd_resolve_brick (brickinfo);
-                if (!gf_uuid_compare(brickinfo->uuid, MY_UUID)) {
-                        if (!realpath (brickinfo->path, abspath)) {
-                                gf_msg (this->name, GF_LOG_CRITICAL, errno,
-                                        GD_MSG_BRICKINFO_CREATE_FAIL, "realpath"
-                                        " () failed for brick %s. The "
-                                        "underlying file system may be in bad"
-                                        " state", brickinfo->path);
-                                ret = -1;
-                                goto out;
+                if (!volinfo->is_snap_volume &&
+                    gf_uuid_is_null (volinfo->restored_from_snap)) {
+                        /* By now if the brick is a local brick then it will be
+                         * able to resolve which is the only thing we want now
+                         * for checking  whether the brickinfo->uuid matches
+                         * with MY_UUID for realpath check. Hence do not handle
+                         * error
+                         */
+                        (void)glusterd_resolve_brick (brickinfo);
+                        if (!gf_uuid_compare(brickinfo->uuid, MY_UUID)) {
+                                if (!realpath (brickinfo->path, abspath)) {
+                                        gf_msg (this->name, GF_LOG_CRITICAL,
+                                                errno,
+                                                GD_MSG_BRICKINFO_CREATE_FAIL,
+                                                "realpath() failed for brick %s"
+                                                ". The underlying file system "
+                                                "may be in bad state",
+                                                brickinfo->path);
+                                        ret = -1;
+                                        goto out;
+                                }
+                                strncpy (brickinfo->real_path, abspath,
+                                         strlen(abspath));
                         }
-                        strncpy (brickinfo->real_path, abspath,
-                                 strlen(abspath));
                 }
                 cds_list_add_tail (&brickinfo->brick_list, &volinfo->bricks);
                 brick_count++;
@@ -3216,6 +3226,7 @@ glusterd_recreate_vol_brick_mounts (xlator_t  *this,
         glusterd_brickinfo_t    *brickinfo           = NULL;
         int32_t                  ret                 = -1;
         struct stat              st_buf              = {0, };
+        char                     abspath[PATH_MAX]   = {0};
 
         GF_ASSERT (this);
         GF_ASSERT (volinfo);
@@ -3272,6 +3283,21 @@ glusterd_recreate_vol_brick_mounts (xlator_t  *this,
                                 GD_MSG_BRK_MNTPATH_MOUNT_FAIL,
                                 "Failed to mount brick_mount_path");
                 }
+                if (!gf_uuid_compare(brickinfo->uuid, MY_UUID)) {
+                        if (!realpath (brickinfo->path, abspath)) {
+                                gf_msg (this->name, GF_LOG_CRITICAL,
+                                        errno,
+                                        GD_MSG_BRICKINFO_CREATE_FAIL,
+                                        "realpath() failed for brick %s"
+                                        ". The underlying file system "
+                                        "may be in bad state",
+                                        brickinfo->path);
+                                ret = -1;
+                                goto out;
+                        }
+                        strncpy (brickinfo->real_path, abspath,
+                                 strlen(abspath));
+                }
 
                 if (brick_mount_path) {
                         GF_FREE (brick_mount_path);