[Cluster-devel] qdisk - memcpy incorrect(?)

[Neale Ferguson]

Hi,
 In diskRawRead in disk.c there is the following code:

       readret = posix_memalign((void **)&alignedBuf, disk->d_pagesz, disk->d_blksz);
        if (readret < 0) {
                return -1;
        }

        io_state(STATE_READ);
        readret = read(disk->d_fd, alignedBuf, readlen);
        io_state(STATE_NONE);
        if (readret > 0) {
                if (readret > len) {
                        memcpy(alignedBuf, buf, len);
                        readret = len;
                } else {
                        memcpy(alignedBuf, buf, readret);
                }
        }

        free(alignedBuf);

The memcpy() above have the src/dst operands swapped. We read into alignedBuf and are supposed to copy to buf. I’m not sure why qdiskd works sometimes and not others.

--- cluster-3.0.12.1/cman/qdisk/disk.c    2013/05/16 16:45:49    1.1
+++ cluster-3.0.12.1/cman/qdisk/disk.c    2013/05/16 16:46:29
@@ -430,14 +430,14 @@
     io_state(STATE_READ);
     readret = read(disk->d_fd, alignedBuf, readlen);
     io_state(STATE_NONE);
     if (readret > 0) {
         if (readret > len) {
-            memcpy(alignedBuf, buf, len);
+            memcpy(buf, alignedBuf, len);
             readret = len;
         } else {
-            memcpy(alignedBuf, buf, readret);
+            memcpy(buf, alignedBuf, readret);
         }
     }

     free(alignedBuf);
     if (readret != len) {

Neale
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