scoutfs: remove item reading limit

The item reading limit was intended to minimize latency when we were
directly reading cached manifests.  We're now asking the server to walk
the manifest for us and that's a lot more expensive than querying local
cached blocks.

Let's gulp in an entire segment's worth of items if we can.  We'll have
plenty of opportunity to tune this down later.

Signed-off-by: Zach Brown <zab@versity.com>

kmod/src/manifest.c

@@ -482,8 +482,6 @@ out:
  * The segments are immutable at this point so we can use their contents
  * as long as we hold refs.
  */
-#define MAX_ITEMS_READ 32
-
 int scoutfs_manifest_read_items(struct super_block *sb,
 				struct scoutfs_key_buf *key,
 				struct scoutfs_key_buf *end)
@@ -503,10 +501,10 @@ int scoutfs_manifest_read_items(struct super_block *sb,
 	u8 item_flags;
 	int found_ctr;
 	bool found;
+	bool added;
 	int ret = 0;
 	int err;
 	int cmp;
-	int n;
 
 	trace_scoutfs_read_items(sb, key, end);
 
@@ -564,8 +562,8 @@ int scoutfs_manifest_read_items(struct super_block *sb,
 
 	found_ctr = 0;
 
-	for (n = 0; n < MAX_ITEMS_READ; n++) {
-
+	added = false;
+	for (;;) {
 		found = false;
 		found_ctr++;
 
@@ -628,10 +626,11 @@ int scoutfs_manifest_read_items(struct super_block *sb,
 			ret = scoutfs_item_add_batch(sb, &batch, &found_key,
 						     found_val);
 			if (ret) {
-				if (n > 0)
+				if (added)
 					ret = 0;
 				break;
 			}
+			added = true;
 		}
 
 		/* the last successful key determines range end until run out */