File rtslib-Fix-handling-of-sysfs-RW-attrs-that-are-actually-RO.patch of Package python-rtslib-fb

From 10f23379b2d3e2226782e2d6185bee22cc586170 Mon Sep 17 00:00:00 2001
From: Lee Duncan <lduncan@suse.com>
Date: Thu, 15 Oct 2020 14:21:20 -0700
Subject: [PATCH] Fix handling of sysfs RW attrs that are actually RO

Kernel commit 356ba2a8bc8d ("scsi: target: tcmu: Make
gr_support and alua_support attributes writable"), made the
alua_support and pgr_support sysfs attributes writable
so that individual target drivers could change them.
This means that the filesystem attributes might saw
read-write, but the attributes can in fact be read-only.
When a user tries to write to them, in this case,
they EINVAL.

This causes rtslib to throw error messages when one does
a "targetctl restore" like these:

> Storage Object fileio/file01: Cannot set attribute alua_support: [Errno 22] Invalid argument, skipped
> Storage Object fileio/file01: Cannot set attribute pgr_support: [Errno 22] Invalid argument, skipped

While these messages are benign, they will cause confusion, since
(1) there's nothing wrong, and (2) they didn't occur before above-
mentioned kernel commit.

This fix tells rtslib to ignore errno 22 for these two attributes.
---
 rtslib/node.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/rtslib/node.py b/rtslib/node.py
index 415f45d675f9..ed08030002bb 100644
--- a/rtslib/node.py
+++ b/rtslib/node.py
@@ -20,6 +20,7 @@ under the License.
 
 import os
 import stat
+import errno
 from .utils import fread, fwrite, RTSLibError, RTSLibNotInCFS
 
 
@@ -28,6 +29,10 @@ class CFSNode(object):
     # Where is the configfs base LIO directory ?
     configfs_dir = '/sys/kernel/config/target'
 
+    # these two attributes can have file permissions of
+    # read-write but be read-only
+    may_be_ro_attrs = ['alua_support', 'pgr_support']
+
     # CFSNode private stuff
 
     def __init__(self):
@@ -172,7 +177,8 @@ class CFSNode(object):
             try:
                 fwrite(path, "%s" % str(value))
             except Exception as e:
-                raise RTSLibError("Cannot set attribute %s: %s" % (attribute, e))
+                if attribute not in self.may_be_ro_attrs or e.errno != errno.EINVAL:
+                    raise RTSLibError("Cannot set attribute %s: %s" % (attribute, e))
 
     def get_attribute(self, attribute):
         '''
-- 
2.26.2