.

bigfile/file_zodb.cpp

@@ -39,8 +39,7 @@ static int zfile_mmap_setup_read(VMA *vma, BigFile *file, blk_t blk, size_t blkl
 
     tie(mmap, err) = fileh->mmap(blk, blklen, vma);
     if (err != nil) {
-        // XXX no way to return error details to virtmem
-        log::Errorf("%s: mmap_setup_read #[%d +%d): %s", v(fileh), blk, blklen, v(err));
+        log::Errorf("%s", v(err)); // XXX no way to return error details to virtmem
         return -1;
     }
 
@@ -56,13 +55,16 @@ static int zfile_remmap_blk_read(VMA *vma, BigFile *file, blk_t blk) {
 
     error err;
     err = mmap->remmap_blk(blk);
-    if (err != nil)
-        panic(v(err));  // XXX
+    if (err != nil) {
+        log::Errorf("%s", v(err)); // XXX no way to return error details to virtmem
+        return -1;
+    }
+
     return 0;
 }
 
 
-static void zfile_munmap(VMA *vma, BigFile *file) {
+static int zfile_munmap(VMA *vma, BigFile *file) {
     wcfs::_Mapping* mmap   = static_cast<wcfs::_Mapping*>(vma->mmap_overlay_server);
     _ZBigFile*      _zfile = container_of(file, _ZBigFile, __pyx_base.file);
 
@@ -71,8 +73,12 @@ static void zfile_munmap(VMA *vma, BigFile *file) {
 
     error err;
     err = mmap->unmap();
-    if (err != nil)
-        panic(v(err));  // XXX
+    if (err != nil) {
+        log::Errorf("%s", v(err)); // XXX no way to return error details to virtmem
+        return -1;
+    }
+
+    return 0;
 }
 
 

bigfile/tests/test_virtmem.c

@@ -1191,12 +1191,13 @@ int mmapfile_remmap_blk_read(VMA *vma, BigFile *file, blk_t blk) {
     return 0;
 }
 
-void mmapfile_munmap(VMA *vma, BigFile *file) {
+int mmapfile_munmap(VMA *vma, BigFile *file) {
     BigFileMMap *f = upcast(BigFileMMap*, file);
     size_t len = vma->addr_stop - vma->addr_start;
 
     f->nmunmap++;
     xmunmap((void *)vma->addr_start, len);
+    return 0;
 }
 
 static const struct bigfile_ops mmapfile_ops = {

bigfile/virtmem.c

@@ -337,7 +337,8 @@ void vma_unmap(VMA *vma)
     /* unmap whole vma at once - the kernel unmaps each mapping in turn.
      * NOTE error here would mean something is broken */
     if (fileh->mmap_overlay) {
-        fileh->file->file_ops->munmap(vma, fileh->file);
+        int err = fileh->file->file_ops->munmap(vma, fileh->file);
+        BUG_ON(err);
     } else {
         xmunmap((void *)vma->addr_start, len);
     }

include/wendelin/bigfile/file.h

@@ -157,17 +157,16 @@ struct bigfile_ops {
      * RW dirty page was discarded.
      *
      * Called under virtmem lock.       XXX hard to rework to call with !virt_lock
-     *
-     * XXX error -> bug (must not fail)
+     * Virtmem considers remmap_blk_read failure as fatal.
      */
     int (*remmap_blk_read) (VMA *vma, BigFile *file, blk_t blk);
 
     /* munmap is called when vma set up via mmap_setup_read is going to be unmapped.
      *
      * Called under virtmem lock.       TODO easy to rework to call with !virt_lock
-     * Must not fail.
+     * Virtmem considers munmap failure as fatal.
      */
-    void (*munmap) (VMA *vma, BigFile *file);
+    int (*munmap) (VMA *vma, BigFile *file);
 };
 typedef struct bigfile_ops bigfile_ops;