Bug 12951 - mount.cifs fails on DFS share with smb protocol version >= 2.0
Summary: mount.cifs fails on DFS share with smb protocol version >= 2.0
Status: RESOLVED DUPLICATE of bug 12917
Alias: None
Product: CifsVFS
Classification: Unclassified
Component: kernel fs (show other bugs)
Version: 3.x
Hardware: x64 Linux
: P5 normal
Target Milestone: ---
Assignee: Steve French
QA Contact: cifs QA contact
Depends on:
Reported: 2017-08-08 12:05 UTC by Christian Garling
Modified: 2020-07-23 12:39 UTC (History)
1 user (show)

See Also:

Logs and tcpdump trace files (6.00 KB, application/gzip)
2017-08-08 12:05 UTC, Christian Garling
no flags Details

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Description Christian Garling 2017-08-08 12:05:37 UTC
Created attachment 13451 [details]
Logs and tcpdump trace files

We are experiencing problems with mounting a DFS share with smb protocol version 2.0 and above on a Windows Server 2008 R2. We have tested the DFS connection on a Ubuntu 16.04.3 system with kernel 4.12.5 from mainline ppa. The command for testing was:

mount -v -t cifs //office.babiel.com/Organisation /mnt/dfs -o username=<username>,domain=OFFICE,vers=2.0

mount -v -t cifs //office.babiel.com/Organisation /mnt/dfs -o username=<username>,domain=OFFICE,vers=2.1

Please find the logs and traces from these commands attached:

echo 'module cifs +p' > /sys/kernel/debug/dynamic_debug/control
echo 'file fs/cifs/* +p' > /sys/kernel/debug/dynamic_debug/control
echo 1 > /proc/fs/cifs/cifsFYI
echo 1 > /sys/module/dns_resolver/parameters/debug
dmesg --clear
tcpdump -w ${testcase}.pcap & pid=$!
sleep 3
mount.cifs .... (see above)
sleep 3
kill $pid
dmesg > ${testcase}.log

Best regards, Christian Garling
Comment 1 Aurélien Aptel 2017-09-25 13:14:06 UTC
Finally taking a look at this.

This seems to also be a problem of cifs.ko failing the initial tree connect and not using the IPC tcon for dfs at the right time.

This is a dupe of #12917
Comment 2 Aurélien Aptel 2020-07-23 12:39:12 UTC

*** This bug has been marked as a duplicate of bug 12917 ***