[CRIU] [PATCHv2 4/4] man: Describe --root option requirements

[Radostin Stoyanov]

These requirements have been described in

https://github.com/opencontainers/runc/blob/b133feae/libcontainer/container_linux.go#L1265

Signed-off-by: Radostin Stoyanov <rstoyanov1 at gmail.com>
---
 Documentation/criu.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/criu.txt b/Documentation/criu.txt
index 2729bc95a..133a094c0 100644
--- a/Documentation/criu.txt
+++ b/Documentation/criu.txt
@@ -414,6 +414,8 @@ usually need to be escaped from shell.
 
 *-r*, *--root* 'path'::
     Change the root filesystem to 'path' (when run in a mount namespace).
+    This option is required to restore a mount namespace. The directory
+    'path' must be a mount point and its parent must not be overmounted.
 
 *--external* 'type'*[*'id'*]:*'value'::
     Restore an instance of an external resource. The generic syntax is
-- 
2.21.0