[Devel] [PATCH RHEL8 COMMIT] ve/devmnt: fix ignore device permissions for pseudosuper

[Konstantin Khorenko]

The commit is pushed to "branch-rh8-4.18.0-305.3.1.vz8.7.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-305.3.1.vz8.7.10
------>
commit f04a8be364fc9e27060b6dccb1a0011e138f0041
Author: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
Date:   Fri Aug 27 20:45:17 2021 +0300

    ve/devmnt: fix ignore device permissions for pseudosuper
    
    Imagine we have
     1) ve->is_pseudosuper == true
     2) err returned from ve_devmnt_check == -EPERM
     3) remount == true
    
    In this case ((ve->is_pseudosuper || !err) && !remount) == false, and
    thus "err = ve_devmnt_insert" is not called, meaning that err remains
    -EPERM, and ve_devmnt_process fails with -EPERM. Would be more logical
    to just ignore error from ve_devmnt_check setting err to 0 as if
    ve_devmnt_check passed with no error.
    
    Fixes: b405a6b90577 ("ve/fs: namespace -- Ignore device permissions
    during restore")
    Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
---
 fs/namespace.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 2009130cd51e..6eece186c568 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2672,13 +2672,15 @@ int ve_devmnt_process(struct ve_struct *ve, dev_t dev, void **data_pp, int remou
 	list_for_each_entry(devmnt, &ve->devmnt_list, link) {
 		if (devmnt->dev == dev) {
 			err = ve_devmnt_check(data, devmnt->allowed_options);
-
 			/*
 			 * In case of @is_pseudouser set, ie restore procedure,
 			 * we don't check for allowed options filtering, since
 			 * restore mode is special.
 			 */
-			if ((ve->is_pseudosuper || !err) && !remount)
+			if (ve->is_pseudosuper)
+				err = 0;
+
+			if (!err && !remount)
 				err = ve_devmnt_insert(data, devmnt->hidden_options);
 
 			break;