Libguestfs - Nov 2016 - [PATCH 1/2] daemon: allow to change the labels of swap partitions

---
 daemon/daemon.h      |  1 +
 daemon/labels.c      |  3 +++
 daemon/swap.c        | 21 +++++++++++++++++++++
 generator/actions.ml |  4 ++++
 4 files changed, 29 insertions(+)

diff --git a/daemon/daemon.h b/daemon/daemon.h
index 79a5288..2379e31 100644
--- a/daemon/daemon.h
+++ b/daemon/daemon.h
@@ -254,6 +254,7 @@ extern int64_t ntfs_minimum_size (const char *device);
 
 /*-- in swap.c --*/
 extern int swap_set_uuid (const char *device, const char *uuid);
+extern int swap_set_label (const char *device, const char *label);
 
 /* ordinary daemon functions use these to indicate errors
  * NB: you don't need to prefix the string with the current command,
diff --git a/daemon/labels.c b/daemon/labels.c
index 20f27cb..aaa3eaf 100644
--- a/daemon/labels.c
+++ b/daemon/labels.c
@@ -85,6 +85,9 @@ do_set_label (const mountable_t *mountable, const char *label)
   else if (STREQ (vfs_type, "xfs"))
     r = xfslabel (mountable->device, label);
 
+  else if (STREQ (vfs_type, "swap"))
+    r = swap_set_label (mountable->device, label);
+
   else
     NOT_SUPPORTED (-1, "don't know how to set the label for
'%s' filesystems",
                    vfs_type);
diff --git a/daemon/swap.c b/daemon/swap.c
index 9d7839e..028bc1e 100644
--- a/daemon/swap.c
+++ b/daemon/swap.c
@@ -239,3 +239,24 @@ swap_set_uuid (const char *device, const char *uuid)
 
   return 0;
 }
+
+int
+swap_set_label (const char *device, const char *label)
+{
+  int r;
+  CLEANUP_FREE char *err = NULL;
+
+  if (strlen (label) > SWAP_LABEL_MAX) {
+    reply_with_error ("%s: Linux swap labels are limited to %d
bytes",
+                      label, SWAP_LABEL_MAX);
+    return -1;
+  }
+
+  r = command (NULL, &err, str_swaplabel, "-L", label, device,
NULL);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    return -1;
+  }
+
+  return 0;
+}
diff --git a/generator/actions.ml b/generator/actions.ml
index 43de38b..5e0356f 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -10304,6 +10304,10 @@ when trying to set the label.
 
 The label is limited to 11 bytes.
 
+=item swap
+
+The label is limited to 16 bytes.
+
 =back
 
 If there is no support for changing the label
-- 
2.7.4

Handle the swap partition on their own, rebuilding them using the
existing UUID and label.
---
 resize/resize.ml       | 35 ++++++++++++++++++++++++++++-------
 resize/virt-resize.pod |  8 ++++++++
 2 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/resize/resize.ml b/resize/resize.ml
index 7d06f18..59ee5bf 100644
--- a/resize/resize.ml
+++ b/resize/resize.ml
@@ -60,6 +60,7 @@ and partition_content    | ContentPV of int64           (*
physical volume (size of PV) *)
   | ContentFS of string * int64  (* mountable filesystem (FS type, FS size) *)
   | ContentExtendedPartition     (* MBR extended partition *)
+  | ContentSwap                  (* Swap partition *)
 and partition_operation    | OpCopy                       (* copy it as-is, no
resizing *)
   | OpIgnore                     (* ignore it (create on target, but don't
@@ -104,11 +105,13 @@ and string_of_partition_content = function
   | ContentPV sz -> sprintf "LVM PV (%Ld bytes)" sz
   | ContentFS (fs, sz) -> sprintf "filesystem %s (%Ld bytes)" fs
sz
   | ContentExtendedPartition -> "extended partition"
+  | ContentSwap -> "swap"
 and string_of_partition_content_no_size = function
   | ContentUnknown -> "unknown data"
   | ContentPV _ -> "LVM PV"
   | ContentFS (fs, _) -> sprintf "filesystem %s" fs
   | ContentExtendedPartition -> "extended partition"
+  | ContentSwap -> "swap"
 
 (* Data structure describing LVs on the source disk.  This is only
  * used if the user gave the --lv-expand option.
@@ -130,6 +133,7 @@ let debug_logvol lv  
 type expand_content_method    | PVResize | Resize2fs | NTFSResize |
BtrfsFilesystemResize | XFSGrowFS
+  | Mkswap
 
 let string_of_expand_content_method = function
   | PVResize -> s_"pvresize"
@@ -137,6 +141,7 @@ let string_of_expand_content_method = function
   | NTFSResize -> s_"ntfsresize"
   | BtrfsFilesystemResize -> s_"btrfs-filesystem-resize"
   | XFSGrowFS -> s_"xfs_growfs"
+  | Mkswap -> s_"mkswap"
 
 type unknown_filesystems_mode    | UnknownFsIgnore
@@ -414,6 +419,8 @@ read the man page virt-resize(1).
         let fs = g#vfs_type dev in
         if fs = "unknown" then
           ContentUnknown
+        else if fs = "swap" then
+          ContentSwap
         else if fs = "LVM2_member" then (
           let rec loop = function
             | [] ->
@@ -531,7 +538,7 @@ read the man page virt-resize(1).
         assert (
           match typ with
           | ContentPV _ | ContentExtendedPartition -> false
-          | ContentUnknown | ContentFS _ -> true
+          | ContentUnknown | ContentFS _ | ContentSwap -> true
         );
 
         { lv_name = name; lv_type = typ; lv_operation = LVOpNone }
@@ -558,6 +565,7 @@ read the man page virt-resize(1).
       | ContentFS (("xfs"), _) when !xfs_available -> true
       | ContentFS _ -> false
       | ContentExtendedPartition -> false
+      | ContentSwap -> true
     else
       fun _ -> false
 
@@ -572,6 +580,7 @@ read the man page virt-resize(1).
       | ContentFS (("xfs"), _) when !xfs_available -> XFSGrowFS
       | ContentFS _ -> assert false
       | ContentExtendedPartition -> assert false
+      | ContentSwap -> Mkswap
     else
       fun _ -> assert false
   in
@@ -665,6 +674,7 @@ read the man page virt-resize(1).
         | ContentExtendedPartition ->
           error (f_"%s: This extended partition contains logical
partitions which might be damaged by shrinking it.  If you want to shrink this
partition, you need to use the '--resize-force' option, but that could
destroy logical partitions within this partition.  (This error came from
'%s' option on the command line.)")
             name option
+        | ContentSwap -> ()
       );
 
       p.p_operation <- OpResize newsize
@@ -831,7 +841,8 @@ read the man page virt-resize(1).
             (match p.p_type with
             | ContentUnknown
             | ContentPV _
-            | ContentExtendedPartition -> ()
+            | ContentExtendedPartition
+            | ContentSwap -> ()
             | ContentFS (fs, _) ->
               error (f_"unknown/unavailable method for expanding the %s
filesystem on %s")
                 fs p.p_name
@@ -848,7 +859,8 @@ read the man page virt-resize(1).
             (match lv.lv_type with
             | ContentUnknown
             | ContentPV _
-            | ContentExtendedPartition -> ()
+            | ContentExtendedPartition
+            | ContentSwap -> ()
             | ContentFS (fs, _) ->
               error (f_"unknown/unavailable method for expanding the %s
filesystem on %s")
                 fs lv.lv_name;
@@ -886,7 +898,8 @@ read the man page virt-resize(1).
               (match p.p_type with
               | ContentUnknown
               | ContentPV _
-              | ContentExtendedPartition -> ()
+              | ContentExtendedPartition
+              | ContentSwap -> ()
               | ContentFS (fs, _) ->
                 warning (f_"unknown/unavailable method for expanding the
%s filesystem on %s")
                   fs p.p_name;
@@ -916,7 +929,8 @@ read the man page virt-resize(1).
                 (match lv.lv_type with
                 | ContentUnknown
                 | ContentPV _
-                | ContentExtendedPartition -> ()
+                | ContentExtendedPartition
+                | ContentSwap -> ()
                 | ContentFS (fs, _) ->
                   warning (f_"unknown/unavailable method for expanding the
%s filesystem on %s")
                     fs name;
@@ -1199,7 +1213,7 @@ read the man page virt-resize(1).
         message (f_"Copying %s") source;
 
         (match p.p_type with
-         | ContentUnknown | ContentPV _ | ContentFS _ ->
+         | ContentUnknown | ContentPV _ | ContentFS _ | ContentSwap ->
            g#copy_device_to_device ~size:copysize ~sparse source target
 
          | ContentExtendedPartition ->
@@ -1255,7 +1269,7 @@ read the man page virt-resize(1).
 
     | { p_type          (ContentFS _|ContentUnknown|ContentPV _
-            |ContentExtendedPartition) } :: _
+            |ContentExtendedPartition|ContentSwap) } :: _
     | [] -> ()
   );
 
@@ -1312,6 +1326,13 @@ read the man page virt-resize(1).
       | NTFSResize -> g#ntfsresize ~force:ntfsresize_force target
       | BtrfsFilesystemResize -> with_mounted target
g#btrfs_filesystem_resize
       | XFSGrowFS -> with_mounted target g#xfs_growfs
+      | Mkswap ->
+        (* Rebuild the swap using the UUID and label of the existing
+         * swap partition.
+         *)
+        let uuid = g#vfs_uuid target in
+        let label = g#vfs_label target in
+        g#mkswap ~uuid ~label target
     in
 
     (* Expand partition content as required. *)
diff --git a/resize/virt-resize.pod b/resize/virt-resize.pod
index aa01849..2344056 100644
--- a/resize/virt-resize.pod
+++ b/resize/virt-resize.pod
@@ -398,6 +398,14 @@ Btrfs filesystems, if libguestfs was compiled with support
for btrfs.
 
 XFS filesystems, if libguestfs was compiled with support for XFS.
 
+=item *
+
+Linux swap partitions.
+
+Please note that libguestfs I<destroys> the existing swap content
+by recreating it with C<mkswap>, so this should not be used when
+the guest is suspended.
+
 =back
 
 Note that you cannot use I<--expand> and I<--shrink> together.
-- 
2.7.4

On Fri, Nov 25, 2016 at 11:22:26AM +0100, Pino Toscano
wrote:
> ---
>  daemon/daemon.h      |  1 +
>  daemon/labels.c      |  3 +++
>  daemon/swap.c        | 21 +++++++++++++++++++++
>  generator/actions.ml |  4 ++++
>  4 files changed, 29 insertions(+)
> 
> diff --git a/daemon/daemon.h b/daemon/daemon.h
> index 79a5288..2379e31 100644
> --- a/daemon/daemon.h
> +++ b/daemon/daemon.h
> @@ -254,6 +254,7 @@ extern int64_t ntfs_minimum_size (const char *device);
>  
>  /*-- in swap.c --*/
>  extern int swap_set_uuid (const char *device, const char *uuid);
> +extern int swap_set_label (const char *device, const char *label);
>  
>  /* ordinary daemon functions use these to indicate errors
>   * NB: you don't need to prefix the string with the current command,
> diff --git a/daemon/labels.c b/daemon/labels.c
> index 20f27cb..aaa3eaf 100644
> --- a/daemon/labels.c
> +++ b/daemon/labels.c
> @@ -85,6 +85,9 @@ do_set_label (const mountable_t *mountable, const char
*label)
>    else if (STREQ (vfs_type, "xfs"))
>      r = xfslabel (mountable->device, label);
>  
> +  else if (STREQ (vfs_type, "swap"))
> +    r = swap_set_label (mountable->device, label);
> +
>    else
>      NOT_SUPPORTED (-1, "don't know how to set the label for
'%s' filesystems",
>                     vfs_type);
> diff --git a/daemon/swap.c b/daemon/swap.c
> index 9d7839e..028bc1e 100644
> --- a/daemon/swap.c
> +++ b/daemon/swap.c
> @@ -239,3 +239,24 @@ swap_set_uuid (const char *device, const char *uuid)
>  
>    return 0;
>  }
> +
> +int
> +swap_set_label (const char *device, const char *label)
> +{
> +  int r;
> +  CLEANUP_FREE char *err = NULL;
> +
> +  if (strlen (label) > SWAP_LABEL_MAX) {
> +    reply_with_error ("%s: Linux swap labels are limited to %d
bytes",
> +                      label, SWAP_LABEL_MAX);
> +    return -1;
> +  }
> +
> +  r = command (NULL, &err, str_swaplabel, "-L", label,
device, NULL);
> +  if (r == -1) {
> +    reply_with_error ("%s", err);
> +    return -1;
> +  }
> +
> +  return 0;
> +}
> diff --git a/generator/actions.ml b/generator/actions.ml
> index 43de38b..5e0356f 100644
> --- a/generator/actions.ml
> +++ b/generator/actions.ml
> @@ -10304,6 +10304,10 @@ when trying to set the label.
>  
>  The label is limited to 11 bytes.
>  
> +=item swap
> +
> +The label is limited to 16 bytes.
> +
>  =back
>  
>  If there is no support for changing the label
> -- 
> 2.7.4
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs@redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs
Obvious improvement, ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html

On Fri, Nov 25, 2016 at 11:22:27AM +0100, Pino Toscano
wrote:
> Handle the swap partition on their own, rebuilding them using the
> existing UUID and label.
>
>  resize/resize.ml       | 35 ++++++++++++++++++++++++++++-------
>  resize/virt-resize.pod |  8 ++++++++
>  2 files changed, 36 insertions(+), 7 deletions(-)
> 
> diff --git a/resize/resize.ml b/resize/resize.ml
> index 7d06f18..59ee5bf 100644
> --- a/resize/resize.ml
> +++ b/resize/resize.ml
> @@ -60,6 +60,7 @@ and partition_content >    | ContentPV of int64       
(* physical volume (size of PV) *)
>    | ContentFS of string * int64  (* mountable filesystem (FS type, FS
size) *)
>    | ContentExtendedPartition     (* MBR extended partition *)
> +  | ContentSwap                  (* Swap partition *)
>  and partition_operation >    | OpCopy                       (* copy it
as-is, no resizing *)
>    | OpIgnore                     (* ignore it (create on target, but
don't
> @@ -104,11 +105,13 @@ and string_of_partition_content = function
>    | ContentPV sz -> sprintf "LVM PV (%Ld bytes)" sz
>    | ContentFS (fs, sz) -> sprintf "filesystem %s (%Ld bytes)"
fs sz
>    | ContentExtendedPartition -> "extended partition"
> +  | ContentSwap -> "swap"
>  and string_of_partition_content_no_size = function
>    | ContentUnknown -> "unknown data"
>    | ContentPV _ -> "LVM PV"
>    | ContentFS (fs, _) -> sprintf "filesystem %s" fs
>    | ContentExtendedPartition -> "extended partition"
> +  | ContentSwap -> "swap"
>  
>  (* Data structure describing LVs on the source disk.  This is only
>   * used if the user gave the --lv-expand option.
> @@ -130,6 +133,7 @@ let debug_logvol lv >  
>  type expand_content_method >    | PVResize | Resize2fs | NTFSResize |
BtrfsFilesystemResize | XFSGrowFS
> +  | Mkswap
>  
>  let string_of_expand_content_method = function
>    | PVResize -> s_"pvresize"
> @@ -137,6 +141,7 @@ let string_of_expand_content_method = function
>    | NTFSResize -> s_"ntfsresize"
>    | BtrfsFilesystemResize -> s_"btrfs-filesystem-resize"
>    | XFSGrowFS -> s_"xfs_growfs"
> +  | Mkswap -> s_"mkswap"
>  
>  type unknown_filesystems_mode >    | UnknownFsIgnore
> @@ -414,6 +419,8 @@ read the man page virt-resize(1).
>          let fs = g#vfs_type dev in
>          if fs = "unknown" then
>            ContentUnknown
> +        else if fs = "swap" then
> +          ContentSwap
>          else if fs = "LVM2_member" then (
>            let rec loop = function
>              | [] ->
> @@ -531,7 +538,7 @@ read the man page virt-resize(1).
>          assert (
>            match typ with
>            | ContentPV _ | ContentExtendedPartition -> false
> -          | ContentUnknown | ContentFS _ -> true
> +          | ContentUnknown | ContentFS _ | ContentSwap -> true
>          );
>  
>          { lv_name = name; lv_type = typ; lv_operation = LVOpNone }
> @@ -558,6 +565,7 @@ read the man page virt-resize(1).
>        | ContentFS (("xfs"), _) when !xfs_available -> true
>        | ContentFS _ -> false
>        | ContentExtendedPartition -> false
> +      | ContentSwap -> true
>      else
>        fun _ -> false
>  
> @@ -572,6 +580,7 @@ read the man page virt-resize(1).
>        | ContentFS (("xfs"), _) when !xfs_available ->
XFSGrowFS
>        | ContentFS _ -> assert false
>        | ContentExtendedPartition -> assert false
> +      | ContentSwap -> Mkswap
>      else
>        fun _ -> assert false
>    in
> @@ -665,6 +674,7 @@ read the man page virt-resize(1).
>          | ContentExtendedPartition ->
>            error (f_"%s: This extended partition contains logical
partitions which might be damaged by shrinking it.  If you want to shrink this
partition, you need to use the '--resize-force' option, but that could
destroy logical partitions within this partition.  (This error came from
'%s' option on the command line.)")
>              name option
> +        | ContentSwap -> ()
>        );
>  
>        p.p_operation <- OpResize newsize
> @@ -831,7 +841,8 @@ read the man page virt-resize(1).
>              (match p.p_type with
>              | ContentUnknown
>              | ContentPV _
> -            | ContentExtendedPartition -> ()
> +            | ContentExtendedPartition
> +            | ContentSwap -> ()
>              | ContentFS (fs, _) ->
>                error (f_"unknown/unavailable method for expanding the
%s filesystem on %s")
>                  fs p.p_name
> @@ -848,7 +859,8 @@ read the man page virt-resize(1).
>              (match lv.lv_type with
>              | ContentUnknown
>              | ContentPV _
> -            | ContentExtendedPartition -> ()
> +            | ContentExtendedPartition
> +            | ContentSwap -> ()
>              | ContentFS (fs, _) ->
>                error (f_"unknown/unavailable method for expanding the
%s filesystem on %s")
>                  fs lv.lv_name;
> @@ -886,7 +898,8 @@ read the man page virt-resize(1).
>                (match p.p_type with
>                | ContentUnknown
>                | ContentPV _
> -              | ContentExtendedPartition -> ()
> +              | ContentExtendedPartition
> +              | ContentSwap -> ()
>                | ContentFS (fs, _) ->
>                  warning (f_"unknown/unavailable method for expanding
the %s filesystem on %s")
>                    fs p.p_name;
> @@ -916,7 +929,8 @@ read the man page virt-resize(1).
>                  (match lv.lv_type with
>                  | ContentUnknown
>                  | ContentPV _
> -                | ContentExtendedPartition -> ()
> +                | ContentExtendedPartition
> +                | ContentSwap -> ()
>                  | ContentFS (fs, _) ->
>                    warning (f_"unknown/unavailable method for
expanding the %s filesystem on %s")
>                      fs name;
> @@ -1199,7 +1213,7 @@ read the man page virt-resize(1).
>          message (f_"Copying %s") source;
>  
>          (match p.p_type with
> -         | ContentUnknown | ContentPV _ | ContentFS _ ->
> +         | ContentUnknown | ContentPV _ | ContentFS _ | ContentSwap ->
>             g#copy_device_to_device ~size:copysize ~sparse source target
>  
>           | ContentExtendedPartition ->
> @@ -1255,7 +1269,7 @@ read the man page virt-resize(1).
>  
>      | { p_type >          (ContentFS _|ContentUnknown|ContentPV _
> -            |ContentExtendedPartition) } :: _
> +            |ContentExtendedPartition|ContentSwap) } :: _
>      | [] -> ()
>    );
>  
> @@ -1312,6 +1326,13 @@ read the man page virt-resize(1).
>        | NTFSResize -> g#ntfsresize ~force:ntfsresize_force target
>        | BtrfsFilesystemResize -> with_mounted target
g#btrfs_filesystem_resize
>        | XFSGrowFS -> with_mounted target g#xfs_growfs
> +      | Mkswap ->
> +        (* Rebuild the swap using the UUID and label of the existing
> +         * swap partition.
> +         *)
> +        let uuid = g#vfs_uuid target in
> +        let label = g#vfs_label target in
> +        g#mkswap ~uuid ~label target
>      in
>  
>      (* Expand partition content as required. *)
> diff --git a/resize/virt-resize.pod b/resize/virt-resize.pod
> index aa01849..2344056 100644
> --- a/resize/virt-resize.pod
> +++ b/resize/virt-resize.pod
> @@ -398,6 +398,14 @@ Btrfs filesystems, if libguestfs was compiled with
support for btrfs.
>  
>  XFS filesystems, if libguestfs was compiled with support for XFS.
>  
> +=item *
> +
> +Linux swap partitions.
> +
> +Please note that libguestfs I<destroys> the existing swap content
> +by recreating it with C<mkswap>, so this should not be used when
> +the guest is suspended.
> +
>  =back
>  
>  Note that you cannot use I<--expand> and I<--shrink> together.
ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v