daemon: debug segv correct use of dereferencing NULL.

[libguestfs.git] / contrib / visualize-alignment / README

diff --git a/contrib/visualize-alignment/README b/contrib/visualize-alignment/README
index 0009dcf..e68a902 100644 (file)
--- a/contrib/visualize-alignment/README
+++ b/contrib/visualize-alignment/README
@@ -8,6 +8,12 @@ such as a single write, or groups of operations.  You can examine the
 traces by hand (as text files) or turn them into graphical
 visualizations.
 
+IMPORTANT NOTE: This is not upstream (in qemu) nor integrated into
+libguestfs.  We should probably be using the 'blktrace' command
+instead, or if that is not suitable, get a more reliable and useful
+trace mechanism added to qemu (the current patch is not suitable for
+upstreaming).
+
 The *.qtr files are qemu trace files, produced using the unofficial
 qemu patch in the current directory.
 
@@ -48,7 +54,7 @@ qemu patch in the current directory.
       pvcreate /dev/vda : \
       vgcreate VG /dev/vda : \
       lvcreate LV VG 32 : \
-      mkfs-b ext4 4096 /dev/VG/LV
+      mkfs-opts ext4 /dev/VG/LV blocksize:4096
 
   Some points to note:
     * an ext4 filesystem, so it has a journal and extents