Libguestfs - Jul 2016 - [PATCHv2 1/3] mllib: add checking for btrfs subvolume

sparsify case: modified guestfs_is_lv
mllib: fixed is_btrfs_subvolume


Maxim Perevedentsev (3):
  mllib: add checking for btrfs subvolume
  lvm: modify guestfs_is_lv to take mountable
  sysprep: fix btrfs subvolume processing in fs-uuids

 daemon/lvm.c                          |  6 ++++--
 generator/actions.ml                  |  6 +++---
 mllib/common_utils.ml                 |  7 +++++++
 mllib/common_utils.mli                |  3 +++
 sysprep/sysprep_operation_fs_uuids.ml | 16 +++++++++-------
 5 files changed, 26 insertions(+), 12 deletions(-)

--
1.8.3.1

This is needed to skip btrfs subvolumes from output
of list_filesystems where device is needed.
---
 mllib/common_utils.ml  | 7 +++++++
 mllib/common_utils.mli | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml
index 77b9acd..35f6545 100644
--- a/mllib/common_utils.ml
+++ b/mllib/common_utils.ml
@@ -922,3 +922,10 @@ let inspect_mount_root g ?mount_opts_fn root  
 let inspect_mount_root_ro    inspect_mount_root ~mount_opts_fn:(fun _ ->
"ro")
+
+let is_btrfs_subvolume g fs +  try
+    ignore (g#mountable_subvolume fs); true
+  with Guestfs.Error msg as exn ->
+    if g#last_errno () = Guestfs.Errno.errno_EINVAL then false
+    else raise exn
diff --git a/mllib/common_utils.mli b/mllib/common_utils.mli
index 5b0b9bb..d2ed30c 100644
--- a/mllib/common_utils.mli
+++ b/mllib/common_utils.mli
@@ -330,3 +330,6 @@ val inspect_mount_root : Guestfs.guestfs ->
?mount_opts_fn:(string -> string) ->
 val inspect_mount_root_ro : Guestfs.guestfs -> string -> unit
 (** Like [inspect_mount_root], but mounting every mount point as
     read-only. *)
+
+val is_btrfs_subvolume : Guestfs.guestfs -> string -> bool
+(** Checks if a filesystem is a btrfs subvolume. *)
-- 
1.8.3.1

Calling guestfs_is_lv on btrfs subvolume throws an error.
Here we workaround it by taking Mountable instead of Device
and returning 'false' for non-device mountables.
---
 daemon/lvm.c         | 6 ++++--
 generator/actions.ml | 6 +++---
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/daemon/lvm.c b/daemon/lvm.c
index 2b61357..4f02206 100644
--- a/daemon/lvm.c
+++ b/daemon/lvm.c
@@ -863,9 +863,11 @@ lv_canonical (const char *device, char **ret)

 /* Test if a device is a logical volume (RHBZ#619793). */
 int
-do_is_lv (const char *device)
+do_is_lv (const mountable_t *mountable)
 {
-  return lv_canonical (device, NULL);
+  if (mountable->type != MOUNTABLE_DEVICE)
+    return 0;
+  return lv_canonical (mountable->device, NULL);
 }

 /* Return canonical name of LV to caller (RHBZ#638899). */
diff --git a/generator/actions.ml b/generator/actions.ml
index e0931b8..2a69db8 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -9068,7 +9068,7 @@ I<other> keys." };

   { defaults with
     name = "is_lv"; added = (1, 5, 3);
-    style = RBool "lvflag", [Device "device"], [];
+    style = RBool "lvflag", [Mountable "mountable"], [];
     proc_nr = Some 264;
     tests = [
       InitBasicFSonLVM, Always, TestResultTrue (
@@ -9076,9 +9076,9 @@ I<other> keys." };
       InitBasicFSonLVM, Always, TestResultFalse (
         [["is_lv"; "/dev/sda1"]]), []
     ];
-    shortdesc = "test if device is a logical volume";
+    shortdesc = "test if mountable is a logical volume";
     longdesc = "\
-This command tests whether C<device> is a logical volume, and
+This command tests whether C<mountable> is a logical volume, and
 returns true iff this is the case." };

   { defaults with
--
1.8.3.1

guestfs_set_uuid wants device as argument.
Moreover, btrfstune -U is unable to set uuid for subvolumes,
only unmounted partitions are supported.

Here we skip btrfs subvolumes.
---
 sysprep/sysprep_operation_fs_uuids.ml | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/sysprep/sysprep_operation_fs_uuids.ml
b/sysprep/sysprep_operation_fs_uuids.ml
index ed4e81a..f125eb0 100644
--- a/sysprep/sysprep_operation_fs_uuids.ml
+++ b/sysprep/sysprep_operation_fs_uuids.ml
@@ -30,13 +30,15 @@ let rec fs_uuids_perform g root side_effects    List.iter
(function
   | _, "unknown" -> ()
   | dev, typ ->
-    let new_uuid = Common_utils.uuidgen () in
-    try
-      g#set_uuid dev new_uuid
-    with
-      G.Error msg ->
-        warning (f_"cannot set random UUID on filesystem %s type %s:
%s")
-          dev typ msg
+    if not (is_btrfs_subvolume g dev) then (
+      let new_uuid = Common_utils.uuidgen () in
+      try
+        g#set_uuid dev new_uuid
+      with
+        G.Error msg ->
+          warning (f_"cannot set random UUID on filesystem %s type %s:
%s")
+            dev typ msg
+    )
   ) fses
 
 let op = {
-- 
1.8.3.1

It all looks good.  I'm just going to run the tests and if they
pass I'll push it all.

Thanks,

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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