vol: allow non-dafs volume utils to attach with V_READONLY again

[openafs.git] / src / vol / volume_inline.h

diff --git a/src/vol/volume_inline.h b/src/vol/volume_inline.h
index 3707357..1fc8855 100644 (file)
--- a/src/vol/volume_inline.h
+++ b/src/vol/volume_inline.h
@@ -128,8 +128,8 @@ VMustCheckoutVolume(int mode)
  * (or put it in an error state) if we detect that another program
  * claims to be using the volume when we try to attach. We don't always
  * want to do that, since sometimes we know that the volume may be in
- * use by another program, e.g. when we are attaching with V_PEEK, and
- * we don't care.
+ * use by another program, e.g. when we are attaching with V_PEEK
+ * or attaching for only reading (V_READONLY).
  *
  * @param mode  the mode of attachment for the volume
  *
@@ -147,9 +147,24 @@ VShouldCheckInUse(int mode)
        return 1;
     }
     if (VMustCheckoutVolume(mode)) {
-       /* assume we checked out the volume from the fileserver, so inUse
-        * should not be set */
-       return 1;
+       /*
+        * Before VShouldCheckInUse() was called, the caller checked out the
+        * volume from the fileserver. The volume may not be in use by the
+        * fileserver, or another program, at this point. The caller should
+        * verify by checking inUse is not set, otherwise the volume state
+        * is in error.
+        *
+        * However, an exception is made for the V_READONLY attach mode.  The
+        * volume may still be in use by the fileserver when a caller has
+        * checked out the volume from the fileserver with the V_READONLY
+        * attach mode, and so it is not an error for the inUse field to be set
+        * at this point. The caller should not check the inUse and may
+        * not change any volume state.
+        */
+       if (mode == V_READONLY) {
+           return 0; /* allowed to be inUse; do not check */
+       }
+       return 1; /* may not be inUse; check */
     }
     return 0;
 }