.

bigfile/tests/tfault.c

 /* Wendelin.bigfile | tests for real faults leading to crash
- * Copyright (C) 2014-2019  Nexedi SA and Contributors.
+ * Copyright (C) 2014-2020  Nexedi SA and Contributors.
  *                          Kirill Smelkov <kirr@nexedi.com>
  *
  * This program is free software: you can Use, Study, Modify and Redistribute
@@ -109,7 +109,7 @@ void fault_in_loadblk()
         .file_ops   = &faulty_ops,
     };
 
-    err = fileh_open(&fh, &f, ram);
+    err = fileh_open(&fh, &f, ram, DONT_MMAP_OVERLAY);
     ok1(!err);
 
     err = fileh_mmap(vma, &fh, 0, 2);
@@ -164,7 +164,7 @@ void fault_in_storeblk()
         .file_ops   = &faulty_ops,
     };
 
-    err = fileh_open(&fh, &f, ram);
+    err = fileh_open(&fh, &f, ram, DONT_MMAP_OVERLAY);
     ok1(!err);
 
     err = fileh_mmap(vma, &fh, 0, 2);

bigfile/virtmem.c

@@ -164,9 +164,8 @@ int fileh_open(BigFileH *fileh, BigFile *file, RAM *ram, FileHOpenFlags flags)
         ASSERT(fops->remmap_blk_read);
         ASSERT(fops->munmap);
     }
-    if (flags == DONT_MMAP_OVERLAY) {
+    if (flags == DONT_MMAP_OVERLAY)
         ASSERT(fops->loadblk);
-    }
 
     sigsegv_block(&save_sigset);
     virt_lock();
@@ -790,9 +789,10 @@ VMFaultResult vma_on_pagefault(VMA *vma, uintptr_t addr, int write)
         /* load block -> pageram memory */
         blk = page->f_pgoffset;     // NOTE because blksize = pagesize
 
-        /* mark page as loading and unlock virtmem before calling loadblk()
+        /* mark page as loading and unlock virtmem before doing actual load via
+         * loadblk() or wcfs.
          *
-         * that call is potentially slow and external code can take other
+         * both calls are potentially slow and external code can take other
          * locks. If that "other locks" are also taken before external code
          * calls e.g. fileh_invalidate_page() in different codepath a deadlock
          * can happen. (similar to storeblk case) */
@@ -864,7 +864,7 @@ VMFaultResult vma_on_pagefault(VMA *vma, uintptr_t addr, int write)
 
     /* (6) page data ready. Mmap it atomically into vma address space, or mprotect
      * appropriately if it was already mmaped. */
-    PageState newstate = PAGE_LOADED;   // XXX vvv PAGE_LOADED_FOR_WRITE ok?
+    PageState newstate = PAGE_LOADED;
     if (write || page->state == PAGE_DIRTY || page->state == PAGE_LOADED_FOR_WRITE) {
         newstate = PAGE_DIRTY;
     }
@@ -878,8 +878,6 @@ VMFaultResult vma_on_pagefault(VMA *vma, uintptr_t addr, int write)
     }
     page->state = max(page->state, newstate);
 
-    // XXX overlay: assert !vma->page_ismappedv[blk]    XXX not ok? (retrying after virt unlock/lock)
-
     vma_mmap_page(vma, page);
     /* wcfs: also mmap the page to all wcfs-backed vmas. If we don't, the
      * memory on those vmas will read with stale data */