Why are we receiving REMOVEXATTR() error messages in glusterfs logs ?

Issue

Different warning messages regarding the removal of extended attributes in gluster volumes can be observed in the client logs:

Example 1:

[2015-08-31 06:21:21.257170]  [MSGID: 114031] [client-rpc-fops.c:1298:client3_3_removexattr_cbk] 13-vol1-client-0: remote operation failed [No data available]
[2015-08-31 06:21:21.257174]  [MSGID: 114031] [client-rpc-fops.c:1298:client3_3_removexattr_cbk] 13-vol1-client-2: remote operation failed [No data available]
[2015-08-31 06:21:21.257406]  [MSGID: 114031] [client-rpc-fops.c:1298:client3_3_removexattr_cbk] 13-vol1-client-4: remote operation failed [No data available]
[2015-08-31 06:21:21.257418]  [MSGID: 114031] [client-rpc-fops.c:1298:client3_3_removexattr_cbk] 13-vol1-client-1: remote operation failed [No data available]

Additionally:

[2018-04-23 11:21:39.553946] W [MSGID: 114031] [client-rpc-fops.c:1233:client3_3_removexattr_cbk] 0-ESB_shared-client-0: remote operation failed [Permission denied]
[2018-04-23 11:21:39.554005] W [MSGID: 114031] [client-rpc-fops.c:1233:client3_3_removexattr_cbk] 0-ESB_shared-client-1: remote operation failed [Permission denied]
[2018-04-23 11:21:39.554030] W [MSGID: 114031] [client-rpc-fops.c:1233:client3_3_removexattr_cbk] 0-ESB_shared-client-2: remote operation failed [Permission denied]

Example 2:

[2018-04-23 11:21:39.553946] W [MSGID: 114031] [client-rpc-fops.c:1233:client3_3_removexattr_cbk] 0-ESB_shared-client-0: remote operation failed [Permission denied]
[2018-04-23 11:21:39.554005] W [MSGID: 114031] [client-rpc-fops.c:1233:client3_3_removexattr_cbk] 0-ESB_shared-client-1: remote operation failed [Permission denied]
[2018-04-23 11:21:39.554030] W [MSGID: 114031] [client-rpc-fops.c:1233:client3_3_removexattr_cbk] 0-ESB_shared-client-2: remote operation failed [Permission denied]
[2018-04-23 11:21:39.558695] W [fuse-bridge.c:1257:fuse_removexattr_cbk] 0-glusterfs-fuse: 14065: REMOVEXATTR() of security.ima on /vol/file => -1 (Permission denied)

In the brick side, the same error messages are observed but they are informational:

[2018-05-04 10:25:42.542278] I [MSGID: 115058] [server-rpc-fops.c:726:server_removexattr_cbk] 0-ESB_shared-server: 25676517: REMOVEXATTR /vol/file1 of key security.ima ==> (Permission denied) [Permission denied]