libzfs: Fix mounting datasets under thread limit pressure

During parallel zpool import, /sbin/zpool will create a separate thread pool for each pool, used to mount that pool's datasets. If the total thread count exceed's the system's limit on threads per process, then tpool_dispatch may fail. If it does, directly execute the mount operation instead. Sponsored by: Axcient Signed-off-by: Alan Somers <[email protected]> Fixes openzfs#16172
asomers · May 8, 2024 · 829a843 · 829a843
1 parent 075068c
commit 829a843
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/lib/libzfs/libzfs_mount.c b/lib/libzfs/libzfs_mount.c
@@ -1098,7 +1098,10 @@ zfs_dispatch_mount(libzfs_handle_t *hdl, zfs_handle_t **handles,
 	mnt_param->mnt_func = func;
 	mnt_param->mnt_data = data;
 
-	(void) tpool_dispatch(tp, zfs_mount_task, (void*)mnt_param);
+	if (tpool_dispatch(tp, zfs_mount_task, (void*)mnt_param)) {
+		/* Could not dispatch to thread pool; execute directly */
+		zfs_mount_task((void*)mnt_param);
+	}
 }
 
 /*