[Libguestfs] [PATCH 3/3] sparsify: Ignore read-only LVs (RHBZ#1185561).

[Richard W.M. Jones]

---
 sparsify/copying.ml  |  4 +++-
 sparsify/in_place.ml |  4 +++-
 sparsify/utils.ml    | 16 ++++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/sparsify/copying.ml b/sparsify/copying.ml
index 8d77964..165dd6e 100644
--- a/sparsify/copying.ml
+++ b/sparsify/copying.ml
@@ -216,9 +216,11 @@ You can ignore this warning or change it to a hard failure using the
     List.exists (fun fs' -> fs = g#canonical_device_name fs') ignores
   in
 
+  let is_read_only_lv = is_read_only_lv g in
+
   List.iter (
     fun fs ->
-      if not (is_ignored fs) then (
+      if not (is_ignored fs) && not (is_read_only_lv fs) then (
         if List.mem fs zeroes then (
           if not quiet then
             printf (f_"Zeroing %s ...\n%!") fs;
diff --git a/sparsify/in_place.ml b/sparsify/in_place.ml
index 751129e..268784c 100644
--- a/sparsify/in_place.ml
+++ b/sparsify/in_place.ml
@@ -69,9 +69,11 @@ and perform g disk format ignores machine_readable quiet zeroes =
     List.exists (fun fs' -> fs = g#canonical_device_name fs') ignores
   in
 
+  let is_read_only_lv = is_read_only_lv g in
+
   List.iter (
     fun fs ->
-      if not (is_ignored fs) then (
+      if not (is_ignored fs) && not (is_read_only_lv fs) then (
         if List.mem fs zeroes then (
           if not quiet then
             printf (f_"Zeroing %s ...\n%!") fs;
diff --git a/sparsify/utils.ml b/sparsify/utils.ml
index 4de7d08..b541286 100644
--- a/sparsify/utils.ml
+++ b/sparsify/utils.ml
@@ -22,9 +22,25 @@ open Printf
 
 open Common_utils
 
+module G = Guestfs
+
 let prog = Filename.basename Sys.executable_name
 let error ?exit_code fs = error ~prog ?exit_code fs
 let warning fs = warning ~prog fs
 let info fs = info ~prog fs
 
 let quote = Filename.quote
+
+(* Return true if the filesystem is a read-only LV (RHBZ#1185561). *)
+let is_read_only_lv (g : G.guestfs) =
+  let lvs = Array.to_list (g#lvs_full ()) in
+  let romap = List.map (
+    fun { G.lv_uuid = lv_uuid; lv_attr = lv_attr } ->
+      lv_uuid, lv_attr.[1] = 'r'
+  ) lvs in
+  fun fs ->
+    if g#is_lv fs then (
+      let uuid = g#lvuuid fs in
+      assoc ~cmp:compare_lvm2_uuids ~default:false uuid romap
+    )
+    else false
-- 
2.1.0