proper way to do defrag of a mountpoint

Usage: "glusterfs-defrag <MOUNTPOINT>"

there are new features added to distribute with this patch:

* bash# getfattr -n trusted.distribute.linkinfo <file>
  Gives output in the format "<hostname>:<directory>", if there is a
  linkfile present, where hostname is server, directory is backend
  directory where the actual linkfile is present.

* bash# getfattr -n trusted.glusterfs.pathinfo <path>
  Gives layout information if directory, and info about actual
  location of file in backend servers, in the form of
  'hostname:directory'. (TODO: should extend it to all xlators)

* bash# getfattr -n trusted.distribute.fix.layout <path>
  scales out the directory layout in distribute, so when new
  servers are added, layouts are fixed to include them.

* removed 'scale-n-defrag.sh' as its no more required.

* changed 'defrag.sh' to have a feature to specify target bricks,
  so defrag happens to only those nodes. moved the file to
  'glusterfs-defrag', which now gets installed to '${prefix}/bin'

* storage/posix:
  takes new option 'hostname' so it can resolve to same hostname
  given during 'gluster volume create'.
  with 'trusted.glusterfs.pathinfo' posix returns the value in
  'hostname:real_path' format.

Signed-off-by: Amar Tumballi <amar@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 1073 ('gluster defrag <VOLNAME>' fails in mainline)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=1073

1 files changed, 109 insertions, 0 deletions

diff --git a/extras/glusterfs-defrag.in b/extras/glusterfs-defrag.in
new file mode 100644
index 00000000000..982878bdbe9
--- /dev/null
+++ b/extras/glusterfs-defrag.in
@@ -0,0 +1,109 @@
+#!/bin/bash
+
+# Please leave 'added_bricks' as empty if you want 100% defrag.
+# If you want to move data to newly added bricks, properly give
+# brick info as "<hostname>:<export-dir>" form (which was given
+# in 'gluster volume create' command)
+# More than one brick can be given with space inbetween.
+
+#
+# (c) 2010 Gluster Inc <http://www.gluster.com/>
+#
+
+set -e;
+
+added_bricks="node1:/gfs/export1"
+
+CP="cp"
+MV="mv"
+
+scan_dir()
+{
+    path=$1;
+    # run defrag on files first #
+    find "$path" -maxdepth 1 -type f -perm +01000 -exec $0 '{}' \;
+
+    for subdir in $(find "$path" -maxdepth 1 -type d | sed 1d); do
+        $0 "$subdir";
+    done
+}
+
+fix_xattr()
+{
+    path=$1;
+    getfattr -n trusted.distribute.fix.layout "$path" 2>/dev/null;
+}
+
+rsync_filename()
+{
+    path=$1
+    dir=$(dirname "$path");
+    file=$(basename "$path");
+
+    echo "$dir/.$file.zr$$";
+}
+
+relocate_file()
+{
+    path=$1;
+    stat_info=$(stat -c '%a' "$path");
+    if [ $stat_info -lt 1000 ] ; then
+        return;
+    fi
+
+    flag=0;
+    linknode=$(getfattr --only-values -n trusted.distribute.linkinfo $path 2>/dev/null);
+    if [ -z $linknode ] ; then
+        return;
+    fi
+
+    for bricks in ${added_bricks}; do
+        current_brick=${linknode:0:${#bricks}};
+        if [ "${bricks}" == "${current_brick}" ]; then
+            flag=1;
+        fi
+    done
+
+    if [ $flag -ne 1 ]; then
+        return;
+    fi
+
+    tmp_path=$(rsync_filename "$path");
+
+    pre_mtime=$(stat -c '%Y' "$path");
+    $CP -a "$path" "$tmp_path";
+    post_mtime=$(stat -c '%Y' "$path");
+
+    if [ $pre_mtime = $post_mtime ]; then
+	chmod -t "$tmp_path";
+	$MV "$tmp_path" "$path";
+	echo "file '$path' relocated"
+    else
+	echo "file '$path' modified during defrag. skipping"
+	rm -f "$tmp_path";
+    fi
+}
+
+defrag_usage()
+{
+    echo "Usage: $0 <directory>"
+}
+
+main()
+{
+    path="$1";
+
+    if [ -z "$path" ]; then
+        defrag_usage;
+        return;
+    fi
+
+    if [ -d "$path" ]; then
+        fix_xattr "$path";
+	scan_dir "$path";
+    else
+	relocate_file "$@";
+    fi
+}
+
+main "$1"