fixed 8dbfd384 from https://gitee.com/zhangdengyu/kernel_liteos_a/pulls/1008

fix: 修复告警
Signed-off-by: Nzhangdengyu <zhangdengyu2@huawei.com>

fs/vfs/bcache/src/bcache.c

@@ -581,8 +581,11 @@ static OsBcacheBlock *AllocNewBlock(OsBcache *bc, BOOL read, UINT64 num)
         DelBlock(bc, prefer);
     }
 
+    if (prefer->used) { /* do not combine with next check */
+        MergeSyncBlocks(bc, prefer); /* prefer->used may be changed here */
+    }
+
     if (prefer->used) {
-        MergeSyncBlocks(bc, prefer);
         BcacheSyncBlock(bc, prefer);
         DelBlock(bc, prefer);
     }

fs/vfs/vnode.c

@@ -260,7 +260,7 @@ int VnodeDrop(void)
 static char *NextName(char *pos, uint8_t *len)
 {
     char *name = NULL;
-    while (*pos == '/') {
+    while (*pos != 0 && *pos == '/') {
         pos++;
     }
     if (*pos == '\0') {