glusterd/snapshot: Modified restore backend

Now instead of creating volume store files first we constructing
the in-memory volinfo first and then generate the backend store
files. This gives lot of flexibility in restore operation.
This patch also fixes the read-only issue with restored snaps.

Change-Id: I51032228a5212fc3b90dc6e93f3539af3eb36074
BUG: 1064688
Signed-off-by: Rajesh Joseph <rjoseph@redhat.com>
Reviewed-on: http://review.gluster.org/7209
Reviewed-by: Sachin Pandit <spandit@redhat.com>
Reviewed-by: Vijaikumar Mallikarjuna <vmallika@redhat.com>

1 files changed, 60 insertions, 419 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index 90886dcf3..24a70eb41 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -4107,298 +4107,11 @@ gd_is_boolean_option (char *key)
         return _gf_false;
 }
 
-/* This is a utility function which will create backup of
- * origin volume file and then replace the origin volume
- * file with a sym-link to snap volume file.
- *
- * @param orig_vol      volinfo of origin volume
- * @param orig_file     file belonging to origin volume
- * @param snap_file     corresponding file in snap volume
- *
- * @return 0 on success and negative value on failure.
- */
-static int
-gd_backup_and_restore_snap_files (glusterd_volinfo_t *orig_vol,
-                                  const char *orig_file,
-                                  const char *snap_file)
-{
-        int             ret                     = -1;
-        char            tmppath[PATH_MAX]       = {0,};
-        xlator_t        *this                   = NULL;
-
-        this = THIS;
-        GF_ASSERT (this);
-        GF_ASSERT (orig_vol);
-        GF_ASSERT (orig_file);
-        GF_ASSERT (snap_file);
-
-        /* If the volume is already a restored volume then we
-         * need not create a backup of files belonging to origin
-         * volume.
-         * We can simply delete the sym-link created by previous
-         * restore.
-         */
-        if (orig_vol->is_volume_restored) {
-                ret = remove (orig_file);
-                if (ret) {
-                        gf_log (this->name, GF_LOG_ERROR, "Failed to "
-                                "remove %s file", orig_file);
-                        goto out;
-                }
-        } else {
-                snprintf (tmppath, sizeof (tmppath), "%s.origin",
-                          orig_file);
-                /* TODO: These temp files need to be deleted once the restored
-                 * operation is successful
-                 */
-
-                /* Create backup of origin volume file */
-                ret = rename (orig_file, tmppath);
-                if (ret) {
-                        gf_log (this->name, GF_LOG_ERROR, "Failed to rename "
-                                "file from %s to %s", orig_file, tmppath);
-                        goto out;
-                }
-        }
-
-        /* Create sym-link to snap file */
-        ret = symlink (snap_file, orig_file);
-        if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to create sym-link "
-                        "to %s file", snap_file);
-                goto out;
-        }
-
-        ret = 0;
-out:
-
-        return ret;
-}
-
-/* This is a utility function which will create a backup copy
- * of origin volume.
- *
- * @param origvol       volinfo of origin volume
- * @param fileformat    This string provides formatting information
- *                      for the file to be backed up. The format
- *                      string should be of <string>%s<string> format.
- *                      Where <string> can be any string and this
- *                      function will replace %s with origin volume
- *                      name. e.g. "trusted-%s-fuse.vol".
- * @param volpath       volume path
- *
- * @return 0 on success and negative value on failure.
- */
-static inline int
-gd_format_path_and_backup_snap_files (glusterd_volinfo_t *origvol,
-                                      const char *fileformat,
-                                      const char *volpath)
-{
-        int     ret                     = -1;
-        char    origfile[PATH_MAX]      = {0,};
-        char    formatstr[PATH_MAX]     = {0,};
-        char    tmppath[PATH_MAX]       = {0,};
-
-        snprintf (formatstr, sizeof (formatstr), "%s/%s", volpath, fileformat);
-        snprintf (origfile, sizeof (origfile), formatstr, origvol->volname);
-
-        /* If the volume is already a restored volume then we
-         * need not create a backup of files belonging to origin
-         * volume.
-         * We can simply delete the sym-link created by previous
-         * restore.
-         */
-        if (origvol->is_volume_restored) {
-                ret = remove (origfile);
-                if (ret) {
-                        gf_log (THIS->name, GF_LOG_ERROR, "Failed to "
-                                "remove %s file", origfile);
-                }
-                goto out;
-        }
-
-        snprintf (tmppath, sizeof (tmppath), "%s.origin", origfile);
-
-        /* Create a backup of this file */
-        ret = rename (origfile, tmppath);
-        if (ret) {
-                gf_log (THIS->name, GF_LOG_ERROR, "failed to restore %s file",
-                        origfile);
-        }
-
-out:
-        return ret;
-}
-
-/* This is a utility function which will backup the origin volume
- * brick folder and then create sym link to the snap_vol brick
- * folder.
- *
- * @param orig_vol      volinfo of origin volume
- * @param snap_vol      volinfo of snap volume
- *
- * @return 0 on success and negative value on failure.
- */
-static int
-gd_restore_snap_brick_vol_files (glusterd_volinfo_t *orig_vol,
-                                 glusterd_volinfo_t *snap_vol)
-{
-        int                     ret                     = -1;
-        char                    path[PATH_MAX]          = {0,};
-        char                    brick[PATH_MAX]         = {0,};
-        char                    oldfilename[PATH_MAX]   = {0,};
-        char                    newfilename[PATH_MAX]   = {0,};
-        glusterd_brickinfo_t    *brickinfo              = NULL;
-        xlator_t                *this                   = NULL;
-        glusterd_conf_t         *conf                   = NULL;
-
-        this = THIS;
-        GF_ASSERT (this);
-        conf = this->private;
-        GF_ASSERT (conf);
-
-        GLUSTERD_GET_VOLUME_DIR (path, orig_vol, conf);
-
-        /* brick count of origin volume and snapshot volume might be
-         * different. Therefore we need to run two different loop to
-         * restore snap brick vol files.
-         */
-        list_for_each_entry (brickinfo, &orig_vol->bricks, brick_list) {
-                GLUSTERD_REMOVE_SLASH_FROM_PATH (brickinfo->path, brick);
-
-                snprintf (oldfilename, sizeof (oldfilename), "%s/%s.%s.%s.vol",
-                          path, orig_vol->volname, brickinfo->hostname,
-                          brick);
-
-                /* If the volume is already a restored volume then we
-                 * need not create a backup of files belonging to origin
-                 * volume.
-                 * We can simply delete the sym-link created by previous
-                 * restore.
-                 */
-                if (orig_vol->is_volume_restored) {
-                        ret = remove (oldfilename);
-                        if (ret) {
-                                gf_log (this->name, GF_LOG_ERROR, "Failed to "
-                                        "remove %s file", oldfilename);
-                                goto out;
-                        }
-                        continue;
-                }
-
-                snprintf (newfilename, sizeof (newfilename), "%s.origin",
-                          oldfilename);
-
-                /* Create a backup of origin volume file */
-                ret = rename (oldfilename, newfilename);
-                if (ret) {
-                        gf_log (this->name, GF_LOG_ERROR, "Failed to rename "
-                                "file from %s to %s", oldfilename,
-                                newfilename);
-                        goto out;
-                }
-        }
-
-        /* Recreate brick files for origin volume */
-        list_for_each_entry (brickinfo, &snap_vol->bricks, brick_list) {
-                ret = glusterd_generate_snap_brick_volfile (orig_vol,
-                                                            brickinfo,
-                                                            snap_vol,
-                                                            _gf_true);
-                if (ret) {
-                        gf_log (this->name, GF_LOG_ERROR, "Failed to generate "
-                                "brick volfile");
-                        goto out;
-                }
-        }
-
-        ret = 0;
-out:
-        return ret;
-}
-
-
-/* This function will update the in-memory representation
- * of the origin volume with the snap volume details.
- *
- * @param orig_vol      origin volume volinfo
- * @param snap_vol      snap volume volinfo
- *
- * @return 0 on success and negative value on failure.
- */
-static int
-gd_update_origin_volume (glusterd_volinfo_t *orig_vol,
-                         glusterd_volinfo_t *snap_vol)
-{
-        int                     ret             = -1;
-        xlator_t                *this           = NULL;
-        glusterd_conf_t         *conf           = NULL;
-        glusterd_brickinfo_t    *brickinfo      = NULL;
-
-        this = THIS;
-        GF_ASSERT (this);
-        conf = this->private;
-        GF_ASSERT (conf);
-        GF_ASSERT (orig_vol);
-        GF_ASSERT (snap_vol);
-
-        /* Update the in-memory volinfo from the store */
-        ret = glusterd_store_update_volinfo (orig_vol, NULL);
-        if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to update "
-                        "volinfo for %s volume", orig_vol->volname);
-                goto out;
-        }
-
-        /* Reset the port number to 0 */
-        orig_vol->port = 0;
-        /* Reset the volume status to stopped */
-        glusterd_set_volume_status (orig_vol, GLUSTERD_STATUS_STOPPED);
-
-        /* Stop the snap volume */
-        list_for_each_entry (brickinfo, &snap_vol->bricks, brick_list) {
-                ret = glusterd_brick_stop (snap_vol, brickinfo, _gf_false);
-                if (ret) {
-                        gf_log (this->name, GF_LOG_ERROR, "Failed to stop "
-                                " %s brick", brickinfo->path);
-                        goto out;
-                }
-        }
-
-        /* Set the volume status to stopped for the snap volume */
-        glusterd_set_volume_status (snap_vol, GLUSTERD_STATUS_STOPPED);
-
-        /* The in-memory brick list for the origin volume should be
-         * replaced with the brick list of snap volume. Therefore
-         * first delete all the bricks from the origin volume and
-         * then read the brick list from the store which is already
-         * updated
-         */
-
-        /* Delete previous brick infos */
-        ret = glusterd_volume_brickinfos_delete (orig_vol);
-        if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to delete "
-                        "brickinfos for %s volume", orig_vol->volname);
-                goto out;
-        }
-
-        /* Retrieve brick list */
-        ret = glusterd_store_retrieve_bricks (orig_vol);
-        if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to retrieve "
-                        "bricks info from store for %s volume",
-                        orig_vol->volname);
-                goto out;
-        }
-
-out:
-        return ret;
-}
-
 /* This function will restore origin volume to it it's snap.
  * The restore operation will simply replace the Gluster origin
  * volume with the snap volume.
+ * TODO: Multi-volume delete to be done.
+ *       Cleanup in case of restore failure is pending.
  *
  * @param orig_vol      volinfo of origin volume
  * @param snap_vol      volinfo of snapshot volume
@@ -4409,17 +4122,11 @@ int
 gd_restore_snap_volume (glusterd_volinfo_t *orig_vol,
                         glusterd_volinfo_t *snap_vol)
 {
-        int                     ret                     = -1;
-        unsigned int            i                       = 0;
-        char                    snappath[PATH_MAX]      = {0,};
-        char                    volpath[PATH_MAX]       = {0,};
-        char                    oldfilename[PATH_MAX]   = {0,};
-        char                    newfilename[PATH_MAX]   = {0,};
-        char                    *types[]                = {NULL, NULL, NULL};
-        xlator_t                *this                   = NULL;
-        glusterd_conf_t         *conf                   = NULL;
-        gf_transport_type       type                    = GF_TRANSPORT_TCP;
-        char                    tmpname[GLUSTERD_MAX_VOLUME_NAME] = {0,};
+        int                     ret             = -1;
+        glusterd_volinfo_t      *new_volinfo    = NULL;
+        glusterd_snap_t         *snap           = NULL;
+        xlator_t                *this           = NULL;
+        glusterd_conf_t         *conf           = NULL;
 
         this = THIS;
         GF_ASSERT (this);
@@ -4428,154 +4135,88 @@ gd_restore_snap_volume (glusterd_volinfo_t *orig_vol,
 
         GF_VALIDATE_OR_GOTO (this->name, orig_vol, out);
         GF_VALIDATE_OR_GOTO (this->name, snap_vol, out);
+        snap = snap_vol->snapshot;
+        GF_VALIDATE_OR_GOTO (this->name, snap, out);
 
-        GLUSTERD_GET_VOLUME_DIR (snappath, snap_vol, conf);
-        GLUSTERD_GET_VOLUME_DIR (volpath, orig_vol, conf);
-
-        /* As mentioned earlier the snapshot restore is done by replacing
-         * the origin volume with the snapshot volume. To do so we have to
-         * replace all backend files belonging to origin volume with the
-         * snapshot volume. And once all the backend files are updated
-         * update the in-memory structure of the origin volume. Also delete
-         * the snapshot volume.
-         * TODO: deleting of snapshot volume can be controlled by user
-         *       controllable option.
+        /* Snap volume must be stoped before performing the
+         * restore operation.
          */
-
-        /* Backup and restore info file */
-        ret = gd_backup_and_restore_snap_files (orig_vol,
-                                                orig_vol->shandle->path,
-                                                snap_vol->shandle->path);
+        ret = glusterd_stop_volume (snap_vol);
         if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to restore info "
-                        "file for %s volume", orig_vol->volname);
+                gf_log (this->name, GF_LOG_ERROR, "Failed to stop "
+                        "snap volume");
                 goto out;
         }
 
-        GLUSTERD_GET_BRICK_DIR (oldfilename, orig_vol, conf);
-        GLUSTERD_GET_BRICK_DIR (newfilename, snap_vol, conf);
-
-        /* Backup and restore bricks folder and it's contents */
-        ret = gd_backup_and_restore_snap_files (orig_vol, oldfilename,
-                                                newfilename);
+        /* Create a new volinfo for the restored volume */
+        ret = glusterd_volinfo_dup (snap_vol, &new_volinfo, _gf_true);
         if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to restore bricks "
-                        "folder for %s volume", orig_vol->volname);
+                gf_log (this->name, GF_LOG_ERROR, "Failed to create volinfo");
                 goto out;
         }
 
-        enumerate_transport_reqs (orig_vol->transport_type, types);
-
+        /* Following entries need to be derived from origin volume. */
+        strcpy (new_volinfo->volname, orig_vol->volname);
+        uuid_copy (new_volinfo->volume_id, orig_vol->volume_id);
+        new_volinfo->snap_count = orig_vol->snap_count;
+        new_volinfo->snap_max_hard_limit = orig_vol->snap_max_hard_limit;
+        new_volinfo->is_volume_restored = _gf_true;
 
-        for (i = 0; NULL != types[i]; i++) {
-                type = transport_str_to_type (types[i]);
-
-                if ((orig_vol->transport_type == GF_TRANSPORT_BOTH_TCP_RDMA) &&
-                                         type == GF_TRANSPORT_RDMA) {
-                        /* Backup trusted rdma-fuse.vol file */
-                        ret = gd_format_path_and_backup_snap_files (orig_vol,
-                                                "trusted-%s.rdma-fuse.vol",
-                                                volpath);
-                        if (ret) {
-                                gf_log (this->name, GF_LOG_ERROR, "Failed to "
-                                        " backup trusted*.rdma-fuse.vol file");
-                                goto out;
-                        }
-
-                        /* Backup rdma-fuse.vol file */
-                        ret = gd_format_path_and_backup_snap_files (orig_vol,
-                                                 "%s.rdma-fuse.vol", volpath);
-                        if (ret) {
-                                gf_log (this->name, GF_LOG_ERROR, "Failed to "
-                                        " backup rdma-fuse.vol file");
-                                goto out;
-                        }
-                } else {
-                        /* Backup trusted fuse.vol file */
-                        ret = gd_format_path_and_backup_snap_files (orig_vol,
-                                                "trusted-%s-fuse.vol", volpath);
-                        if (ret) {
-                                gf_log (this->name, GF_LOG_ERROR, "Failed to "
-                                        " backup trusted*-fuse.vol file");
-                                goto out;
-                        }
+        /* Copy the snap vol info to the new_volinfo.*/
+        ret = glusterd_snap_volinfo_restore (new_volinfo, snap_vol);
+        if (ret) {
+                gf_log (this->name, GF_LOG_ERROR, "Failed to restore snap");
+                (void)glusterd_volinfo_delete (new_volinfo);
+                goto out;
+        }
 
-                        /* Backup fuse.vol file */
-                        ret = gd_format_path_and_backup_snap_files (orig_vol,
-                                                "%s-fuse.vol", volpath);
-                        if (ret) {
-                                gf_log (this->name, GF_LOG_ERROR, "Failed to "
-                                        " backup fuse.vol file");
-                                goto out;
-                        }
+        /* If the orig_vol is already restored then we should delete
+         * the backend LVMs */
+        if (orig_vol->is_volume_restored) {
+                ret = glusterd_lvm_snapshot_remove (orig_vol);
+                if (ret) {
+                        gf_log (this->name, GF_LOG_ERROR, "Failed to remove "
+                                "LVM backend");
+                        (void)glusterd_volinfo_delete (new_volinfo);
+                        goto out;
                 }
         }
 
-        /* The restored client and brick vol files should have all
-         * the entries present in snap vol files but the volume name
-         * for all these entries should still be the origin volume
-         * name.
-         * As of now these volfile generation takes volume name
-         * directly from the volinfo. Therefore instead of changing
-         * all the generate function simply replace the snap volume
-         * name with the origin volume name. And once the vol files
-         * are generated restore the volume name.
+        /* Once the new_volinfo is completely constructed then delete
+         * the orinal volinfo
          */
-        strncpy (tmpname, snap_vol->volname, sizeof(tmpname));
-        strncpy (snap_vol->volname, orig_vol->volname,
-                 sizeof(snap_vol->volname));
-
-        /* Generate trusted client vol file */
-        ret  = generate_snap_client_volfiles (orig_vol, snap_vol,
-                                              GF_CLIENT_TRUSTED, _gf_true);
+        ret = glusterd_volinfo_delete (orig_vol);
         if (ret) {
-                /* Restore the snap volume name */
-                strncpy (snap_vol->volname, tmpname, sizeof(snap_vol->volname));
-                gf_log (this->name, GF_LOG_ERROR, "Failed to generated "
-                        " trusted client vol file for %s volume",
-                        orig_vol->volname);
+                gf_log (this->name, GF_LOG_ERROR, "Failed to delete volinfo");
+                (void)glusterd_volinfo_delete (new_volinfo);
                 goto out;
         }
 
-        ret  = generate_snap_client_volfiles (orig_vol, snap_vol,
-                                              GF_CLIENT_OTHER, _gf_true);
-        if (ret) {
-                /* Restore the snap volume name */
-                strncpy (snap_vol->volname, tmpname, sizeof(snap_vol->volname));
-                gf_log (this->name, GF_LOG_ERROR, "Failed to generated "
-                        " client vol file for %s volume", orig_vol->volname);
-                goto out;
-        }
+        /* New volinfo always shows the status as created. Therefore
+         * set the status to stop. */
+        glusterd_set_volume_status (new_volinfo, GLUSTERD_STATUS_STOPPED);
+
+        list_add_tail (&new_volinfo->vol_list, &conf->volumes);
 
-        ret = gd_restore_snap_brick_vol_files (orig_vol, snap_vol);
+        /* Now delete the snap entry. As a first step delete the snap
+         * volume information stored in store. */
+        ret = glusterd_snap_remove (snap, _gf_false, _gf_true);
         if (ret) {
-                /* Restore the snap volume name */
-                strncpy (snap_vol->volname, tmpname, sizeof(snap_vol->volname));
-                gf_log (this->name, GF_LOG_ERROR, "Failed to generated "
-                        " brick vol files for %s volume", orig_vol->volname);
+                gf_log (this->name, GF_LOG_WARNING, "Failed to delete "
+                        "snap %s", snap->snapname);
                 goto out;
         }
 
-        /* Restore the snap volume name */
-        strncpy (snap_vol->volname, tmpname, sizeof(snap_vol->volname));
-
-        /* Update the in-memory structure of origin volume */
-        ret = gd_update_origin_volume (orig_vol, snap_vol);
+        ret = glusterd_store_volinfo (new_volinfo,
+                                      GLUSTERD_VOLINFO_VER_AC_INCREMENT);
         if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to update "
-                        "origin volume %s", orig_vol->volname);
+                gf_log (this->name, GF_LOG_ERROR, "Failed to store volinfo");
                 goto out;
         }
 
-        /* Update status to restored */
-        orig_vol->is_volume_restored = _gf_true;
 
-        ret = glusterd_store_volinfo (orig_vol, GLUSTERD_VOLINFO_VER_AC_NONE);
-        if (ret) {
-                gf_log (this->name, GF_LOG_ERROR, "Failed to store volume "
-                        "info of %s volume", orig_vol->volname);
-                goto out;
-        }
+        ret = 0;
 out:
-       return ret;
+
+        return ret;
 }