metadump: zero out clean log

When doing an xfs_metadump, if the log is clean, zero it out
for 2 reasons:

 * It'll make the image more compressible
 * It'll eliminate an un-obfuscated metadata source

If the log isn't clean, and the user expected obfuscation, warn
that metadata in the log will not be obfuscated.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/db/metadump.c b/db/metadump.c
index bea4e0001efe878d3ebcaaf4c87a02e5dbd3468e..eb5e9da9e03041918c8bc0cfeb5e2d4baa6fdd8b 100644 (file)
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -17,6 +17,7 @@
  */
 
 #include <libxfs.h>
+#include <libxlog.h>
 #include "bmap.h"
 #include "command.h"
 #include "metadump.h"
@@ -2169,6 +2170,8 @@ copy_sb_inodes(void)
 static int
 copy_log(void)
 {
+       int dirty;
+
        if (show_progress)
                print_progress("Copying log");
 
@@ -2180,6 +2183,31 @@ copy_log(void)
                print_warning("cannot read log");
                return !stop_on_read_error;
        }
+
+       dirty = xlog_is_dirty(mp, &x, 0);
+
+       switch (dirty) {
+       case 0:
+               /* clear out a clean log */
+               if (show_progress)
+                       print_progress("Zeroing clean log");
+               memset(iocur_top->data, 0,
+                       mp->m_sb.sb_logblocks * mp->m_sb.sb_blocksize);
+               break;
+       case 1:
+               /* keep the dirty log */
+               if (obfuscate)
+                       print_warning(
+_("Filesystem log is dirty; image will contain unobfuscated metadata in log."));
+               break;
+       case -1:
+               /* log detection error */
+               if (obfuscate)
+                       print_warning(
+_("Could not discern log; image will contain unobfuscated metadata in log."));
+               break;
+       }
+
        return !write_buf(iocur_top);
 }