Troubleshooting
Problem
Input/Output error in Linux clients running with SMB protocol version 2.0 or higher
Symptom
Applications running on the Linux CIFS client might experience EIO errors when accessing files located on a CIFS share.
Environment
The problem is confirmed in Fedora 20 and Ubuntu 14.04 LTS when using the CIFS kernel client to mount a CIFS share using SMB protocol version 2.0 or higher. Earlier Fedora or Ubuntu releases are probably affected too, but are not currently confirmed/tested.
Diagnosing The Problem
On the Linux client enable verbose mode on the CIFS kernel module by executing 'echo 9 > /proc/fs/cifs/cifsFYI' and reproduce an EIO Input/Output error. Look for error messages such as 'fs/cifs/smb2maperror.c: Mapping SMB2 status code 259 to POSIX err -5' in the kernel log file (/var/log/messages or /var/log/syslog). This indicates that the problem has been hit. To disable verbose mode again execute 'echo 0 > /proc/fs/cifs/cifsFYI'.
Enabling and disabling verbose mode is a concurrent operation. Enabling verbose mode will negatively impact CIFS I/O performance.
Resolving The Problem
Disable usage of SMB version 2.0 or higher on the Linux client and only use SMB protocol version 1.0, which is the default setting:
- un-mount CIFS file system: umount - re-mount CIFS file system without using the 'vers' CIFS mount option or setting 'vers=1'
Notes:
- prior to un-mounting the CIFS file system all applications accessing this file system must be stopped
- SMB protocol version 1.0 can cause reduced file I/O performance
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Document Information
More support for:
Network Attached Storage (NAS)->Scale Out Network Attached Storage
Software version:
1.4
Operating system(s):
Linux
Document number:
689605
Modified date:
17 June 2018
UID
ssg1S1004648