X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=guestfish-actions.pod;h=9b07c402cb16a5dbe1376f4ee17746567959f169;hb=80e15757879c4cf21e0511c62e57c19efb4aab63;hp=fa82ef1b11853c4a25f9496bf0e6d311af287738;hpb=3e408f493496597dc026d20778837f421f05a9dd;p=libguestfs.git

diff --git a/guestfish-actions.pod b/guestfish-actions.pod
index fa82ef1..9b07c40 100644
--- a/guestfish-actions.pod
+++ b/guestfish-actions.pod
@@ -6,6 +6,11 @@ This function adds a virtual CD-ROM disk image to the guest.
 
 This is equivalent to the qemu parameter C<-cdrom filename>.
 
+Note that this call checks for the existence of C<filename>.  This
+stops you from specifying other types of drive which are supported
+by qemu such as C<nbd:> and C<http:> URLs.  To specify those, use
+the general C<config> call instead.
+
 =head2 add-drive | add
 
  add-drive filename
@@ -23,6 +28,32 @@ image).
 
 This is equivalent to the qemu parameter C<-drive file=filename>.
 
+Note that this call checks for the existence of C<filename>.  This
+stops you from specifying other types of drive which are supported
+by qemu such as C<nbd:> and C<http:> URLs.  To specify those, use
+the general C<config> call instead.
+
+=head2 add-drive-ro | add-ro
+
+ add-drive-ro filename
+
+This adds a drive in snapshot mode, making it effectively
+read-only.
+
+Note that writes to the device are allowed, and will be seen for
+the duration of the guestfs handle, but they are written
+to a temporary file which is discarded as soon as the guestfs
+handle is closed.  We don't currently have any method to enable
+changes to be committed, although qemu can support this.
+
+This is equivalent to the qemu parameter
+C<-drive file=filename,snapshot=on>.
+
+Note that this call checks for the existence of C<filename>.  This
+stops you from specifying other types of drive which are supported
+by qemu such as C<nbd:> and C<http:> URLs.  To specify those, use
+the general C<config> call instead.
+
 =head2 aug-close
 
  aug-close