Bug 150157: DosWrite is not returning an error when the disk is full.

We can tell the write failed if we did a partial write.  The patch is
contributed by Michael Kaply <mkaply@us.ibm.com>.

nsprpub/pr/src/md/os2/os2io.c

@@ -253,6 +253,12 @@ _PR_MD_WRITE(PRFileDesc *fd, const void *buf, PRInt32 len)
         return -1;
     }
 
+    if (len != bytes) {
+        rv = ERROR_DISK_FULL;
+        _PR_MD_MAP_WRITE_ERROR(rv);
+        return -1;
+    }
+
     return bytes;
 } /* --- end _PR_MD_WRITE() --- */