[TA3113] Refactor DW rebuild unit test cases. (openzfs#118)

Signed-off-by: satbir <satbir.chhikara@gmail.com>

cmd/uzfs_test/uzfs_test_rebuilding.c

@@ -238,6 +238,7 @@ fetch_modified_data(void *arg)
 	int err;
 	blk_metadata_t md;
 	off_t offset, end;
+	zvol_state_t *snap_zv = NULL;
 	size_t len;
 	int max_count = 4;
 
@@ -251,7 +252,7 @@ fetch_modified_data(void *arg)
 		if (end > r_data->zvol->zv_volsize)
 			len = r_data->zvol->zv_volsize - offset;
 
-		err = uzfs_get_io_diff(repl_data->zvol, &md,
+		err = uzfs_get_io_diff(repl_data->zvol, &md, snap_zv,
 		    uzfs_test_meta_diff_traverse_cb, offset, len,
 		    r_data);
 		if (err)

include/uzfs_rebuilding.h

@@ -42,7 +42,8 @@ int compare_blk_metadata(blk_metadata_t *first_md, blk_metadata_t *second_md);
  * API to access data whose metadata is higer than base_metadata
  */
 int uzfs_get_io_diff(zvol_state_t *zv, blk_metadata_t *base_metadata,
-    uzfs_get_io_diff_cb_t *cb_func, off_t offset, size_t len, void *arg);
+    zvol_state_t *snap_zv, uzfs_get_io_diff_cb_t *cb_func,
+    off_t offset, size_t len, void *arg);
 
 /*
  * uzfs_get_nonoverlapping_ondisk_blks will check on_disk metadata with

lib/libzpool/uzfs_rebuilding.c

@@ -71,15 +71,15 @@ iszero(blk_metadata_t *md)
 		} while (0)
 
 int
-uzfs_get_io_diff(zvol_state_t *zv, blk_metadata_t *low,
+uzfs_get_io_diff(zvol_state_t *zv, blk_metadata_t *low, zvol_state_t *snap,
     uzfs_get_io_diff_cb_t *func, off_t lun_offset, size_t lun_len, void *arg)
 {
 	uint64_t blocksize = zv->zv_volmetablocksize;
 	uint64_t metadata_read_chunk_size = 10 * blocksize;
 	uint64_t metaobjectsize = (zv->zv_volsize / zv->zv_metavolblocksize) *
 	    zv->zv_volmetadatasize;
 	uint64_t metadatasize = zv->zv_volmetadatasize;
-	char *buf, *snap_name;
+	char *buf, *snap_name = NULL;
 	uint64_t i, read;
 	uint64_t offset, len, end;
 	int ret = 0;
@@ -98,15 +98,18 @@ uzfs_get_io_diff(zvol_state_t *zv, blk_metadata_t *low,
 
 	if (end > metaobjectsize)
 		end = metaobjectsize;
-
-	snap_name = kmem_asprintf("%s%llu", IO_DIFF_SNAPNAME, low->io_num);
-
-	ret = get_snapshot_zv(zv, snap_name, &snap_zv);
-	if (ret != 0) {
-		LOG_ERR("Failed to get info about %s@%s io_num %lu",
-		    zv->zv_name, snap_name, low->io_num);
-		strfree(snap_name);
-		return (ret);
+	if (snap == NULL) {
+		snap_name = kmem_asprintf("%s%llu", IO_DIFF_SNAPNAME,
+		    low->io_num);
+		ret = get_snapshot_zv(zv, snap_name, &snap_zv);
+		if (ret != 0) {
+			LOG_ERR("Failed to get info about %s@%s io_num %lu",
+			    zv->zv_name, snap_name, low->io_num);
+			strfree(snap_name);
+			return (ret);
+		}
+	} else {
+		snap_zv = snap;
 	}
 
 	metadata_read_chunk_size = (metadata_read_chunk_size / metadatasize) *
@@ -185,17 +188,19 @@ uzfs_get_io_diff(zvol_state_t *zv, blk_metadata_t *low,
 		}
 	}
 
-	uzfs_close_dataset(snap_zv);
+	if (snap == NULL) {
+		uzfs_close_dataset(snap_zv);
 
-	/*
-	 * TODO: if we failed to destroy snapshot here then
-	 * this should be handled separately from application.
-	 */
-	if (end == metaobjectsize)
-		destroy_snapshot_zv(zv, snap_name);
+		/*
+		 * TODO: if we failed to destroy snapshot here then
+		 * this should be handled separately from application.
+		 */
+		if (end == metaobjectsize)
+			destroy_snapshot_zv(zv, snap_name);
 
+		strfree(snap_name);
+	}
 	umem_free(buf, metadata_read_chunk_size);
-	strfree(snap_name);
 	return (ret);
 }
 

lib/libzrepl/data_conn.c

@@ -1122,6 +1122,7 @@ uzfs_zvol_rebuild_scanner(void *arg)
 {
 	int		fd = (uintptr_t)arg;
 	zvol_info_t	*zinfo = NULL;
+	zvol_state_t	*snap_zv = NULL;
 	zvol_io_hdr_t	hdr;
 	int 		rc = 0;
 	zvol_rebuild_t	warg;
@@ -1213,7 +1214,7 @@ uzfs_zvol_rebuild_scanner(void *arg)
 				sleep(5);
 #endif
 			rc = uzfs_get_io_diff(zinfo->main_zv, &metadata,
-			    uzfs_zvol_rebuild_scanner_callback,
+			    snap_zv, uzfs_zvol_rebuild_scanner_callback,
 			    rebuild_req_offset, rebuild_req_len, &warg);
 			if (rc != 0) {
 				LOG_ERR("Rebuild scanning failed on zvol %s ",