feat(zap): zap list will take a limit

Signed-off-by: sundengyu <dengyu.sun@iomesh.com>

src/bindings/async_sys.rs

@@ -282,6 +282,8 @@ pub unsafe extern "C" fn libuzfs_dataset_expand_c(arg: *mut c_void) {
 pub struct LibuzfsZapListArg {
     pub dhp: *mut libuzfs_dataset_handle_t,
     pub obj: u64,
+    pub limit: usize,
+
     pub err: i32,
     pub list: Vec<(String, Vec<u8>)>,
 }
@@ -328,6 +330,10 @@ pub unsafe extern "C" fn libuzfs_zap_list_c(arg: *mut c_void) {
         let name = String::from_utf8(name).unwrap();
         arg.list.push((name, value));
 
+        if arg.list.len() >= arg.limit {
+            break;
+        }
+
         arg.err = libuzfs_zap_iterator_advance(iter);
         if arg.err != 0 {
             if arg.err == libc::ENOENT {

src/dataset.rs

@@ -365,10 +365,12 @@ impl Dataset {
         self.claim_inode(ino, gen, InodeType::DIR).await
     }
 
-    pub async fn zap_list(&self, zap_obj: u64) -> Result<Vec<(String, Vec<u8>)>> {
+    pub async fn zap_list(&self, zap_obj: u64, limit: usize) -> Result<Vec<(String, Vec<u8>)>> {
         let mut arg = LibuzfsZapListArg {
             dhp: self.dhp,
             obj: zap_obj,
+            limit,
+
             err: 0,
             list: Vec::new(),
         };

src/tests/dataset_tests.rs

@@ -496,7 +496,7 @@ async fn uzfs_zap_iterator_test() {
     let remover_handle = tokio::task::spawn(async move {
         let mut total_ops = num_adders * num_ops_per_adder;
         while total_ops > 0 {
-            for (key, value) in ds_remover.zap_list(zap_obj).await.unwrap() {
+            for (key, value) in ds_remover.zap_list(zap_obj, usize::MAX).await.unwrap() {
                 ds_remover.zap_remove(zap_obj, &key).await.unwrap();
                 assert_eq!(key.as_bytes(), value.as_slice());
                 total_ops -= 1;