From f2d816573ffba9c5a2022ac5b3b6514eaf02d0f7 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Thu, 14 Jul 2011 11:39:11 +0100
Subject: [PATCH] resize: Add btrfs support to virt-resize (RHBZ#721275).

---
 resize/resize.ml       | 18 ++++++++++++++++--
 resize/virt-resize.pod | 11 ++++++++---
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 8e7057c..d4455eb 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -144,8 +144,9 @@ read the man page virt-resize(1).
   lv_expands, ntfsresize_force, output_format,
   quiet, resizes, resizes_force, shrink
 
-(* Default to true, since NTFS support is usually available. *)
+(* Default to true, since NTFS and btrfs support are usually available. *)
 let ntfs_available = ref true
+let btrfs_available = ref true
 
 (* Add in and out disks to the handle and launch. *)
 let connect_both_disks () =
@@ -163,6 +164,7 @@ let connect_both_disks () =
 
   (* Update features available in the daemon. *)
   ntfs_available := feature_available g [|"ntfsprogs"; "ntfs3g"|];
+  btrfs_available := feature_available g [|"btrfs"|];
 
   g
 
@@ -373,12 +375,14 @@ let lvs =
 (* These functions tell us if we know how to expand the content of
  * a particular partition or LV, and what method to use.
  *)
-type expand_content_method = PVResize | Resize2fs | NTFSResize
+type expand_content_method =
+  | PVResize | Resize2fs | NTFSResize | BtrfsFilesystemResize
 
 let string_of_expand_content_method = function
   | PVResize -> "pvresize"
   | Resize2fs -> "resize2fs"
   | NTFSResize -> "ntfsresize"
+  | BtrfsFilesystemResize -> "btrfs-filesystem-resize"
 
 let can_expand_content =
   if expand_content then
@@ -387,6 +391,7 @@ let can_expand_content =
     | ContentPV _ -> true
     | ContentFS (("ext2"|"ext3"|"ext4"), _) -> true
     | ContentFS (("ntfs"), _) when !ntfs_available -> true
+    | ContentFS (("btrfs"), _) when !btrfs_available -> true
     | ContentFS (_, _) -> false
   else
     fun _ -> false
@@ -398,6 +403,7 @@ let expand_content_method =
     | ContentPV _ -> PVResize
     | ContentFS (("ext2"|"ext3"|"ext4"), _) -> Resize2fs
     | ContentFS (("ntfs"), _) when !ntfs_available -> NTFSResize
+    | ContentFS (("btrfs"), _) when !btrfs_available -> BtrfsFilesystemResize
     | ContentFS (_, _) -> assert false
   else
     fun _ -> assert false
@@ -920,6 +926,14 @@ let () =
           g#e2fsck_f target;
           g#resize2fs target
       | NTFSResize -> g#ntfsresize_opts ~force:ntfsresize_force target
+      | BtrfsFilesystemResize ->
+          (* Complicated ...  Btrfs forces us to mount the filesystem
+           * in order to resize it.
+           *)
+          assert (Array.length (g#mounts ()) = 0);
+          g#mount_options "" target "/";
+          g#btrfs_filesystem_resize "/";
+          g#umount "/"
     in
 
     (* Expand partition content as required. *)
diff --git a/resize/virt-resize.pod b/resize/virt-resize.pod
index 6a93e46..a071110 100644
--- a/resize/virt-resize.pod
+++ b/resize/virt-resize.pod
@@ -133,9 +133,9 @@ to fill the rest of the available space:
 If the expanded partition in the image contains a filesystem or LVM
 PV, then if virt-resize knows how, it will resize the contents, the
 equivalent of calling a command such as L<pvresize(8)>,
-L<resize2fs(8)> or L<ntfsresize(8)>.  However virt-resize does not
-know how to resize some filesystems, so you would have to online
-resize them after booting the guest.
+L<resize2fs(8)>, L<ntfsresize(8)> or L<btrfs(8)>.  However virt-resize
+does not know how to resize some filesystems, so you would have to
+online resize them after booting the guest.
 
 Other options are covered below.
 
@@ -274,6 +274,10 @@ LVM PVs (physical volumes).  virt-resize does not usually resize
 anything inside the PV, but see the I<--LV-expand> option.  The user
 could also resize LVs as desired after boot.
 
+=item *
+
+Btrfs filesystems, if libguestfs was compiled with support for btrfs.
+
 =back
 
 Note that you cannot use I<--expand> and I<--shrink> together.
@@ -530,6 +534,7 @@ L<pvresize(8)>,
 L<lvresize(8)>,
 L<resize2fs(8)>,
 L<ntfsresize(8)>,
+L<btrfs(8)>,
 L<virsh(1)>,
 L<parted(8)>,
 L<truncate(1)>,
-- 
1.8.3.1