[SOLVED] Enable CONFIG_CIFS_SMB2 and CONFIG_CIFS_SMB311 on Linux 4.4.140

kjhambrick · 07-15-2018, 06:27 PM

All --

I tried enabling CONFIG_CIFS_SMB2 and CONFIG_CIFS_SMB311 for Linux 4.4.140 on my Slackware64 14.2 Laptop after reading this LQ thread: https://www.linuxquestions.org/quest...nt-4175633789/

As I reported in lukameen's thread, I lost my Synaptics Touchpad when I did.

Yesterday's Slackware 14.2+current kernel-firmware update made me wonder if I needed to update the firmware to fix my issue with the Touchpad.

I updated my Firmware and then the Touchpad worked for my Laptop !

Attached are my HUGE and GENERIC Configs

I'll be disabling SMBv1 on a Windows 10 Test Box to see if I can now mount the share with the mount options { vers=2.0, vers=2.1, vers=3.11 }

Probably next weekend again ...

Thanks to lukameen for bringing this one up !

-- kjh

p.s. I should report that `mount -t cifs` without vers= options is still working for the Win10 Box with SMBv1 Enabled ...

I've not dug around yet in the logs to see what I can see but preliminary results are promising

brobr · 07-19-2018, 11:29 AM

Well, hopefully this observation is relevant...

Today I tried to backup to a cifs-mount at work via rsync and had no luck. The process (on the -current kernel 4.14.55) hung and I got nasty errors in my dmesg; basically as reported here: Weird kernel error with CIFS / general protection fault.

A workaround has been suggested here: bugs.archlinux.org/task/57474 where cifs option -vers=1.0 is proposed (instead of 3.0 or 2.1, which was the setting that worked before -- after reducing from 3.0 a while ago).

With the setting vers=1.0 for mount.cifs the backup went well. So maybe it is not only/immediately a kernel-configuration issue but more how mount.cifs is called?? And thus dependent on the settings of the (windows)server one connects to....?

hth

rob

kjhambrick · 07-19-2018, 03:48 PM

Eeek !

Thanks for the heads-up brobr !

You probably saved my Saturday

I built and installed 4.4.142 today including CONFIG_CIFS_SMB2 and CONFIG_CIFS_SMB311 and I was going to try almost exactly what you did ... mount the Win10 PeeCee Share and pull the Data back to the Linux BackUp Box from the mounted CIFS directory.

I believe I'll put my scheduled testing off for a bit

Thanks again.

-- kjh

brobr · 07-19-2018, 05:47 PM

Still, it doesn't look right, kjh. Was vers=1.0 not banned because of wannacry/petya vulnerabilities? Also, as 'duckgoing' just showed me, modern windows servers negotiate with the client what version to use:

Quote:

Please note that SMB clients and SMB servers negotiate the SMB dialect that they will use based on each side’s offer.

as explained here:

windows-server-2012-r2-which-version-of-the-smb-protocol-smb-1-0-smb-2-0-smb-2-1-smb-3-0-or-smb-3-02-are-you-using/ or here: whats-new-in-smb-3-1-1-in-the-windows-server-2016

So maybe something is going wrong at our client-side (as the most recent changes were the -current kernel-updates at my end; last samba-update was in May).

It has also been submitted as a kernel bug here:cifs: generic/020 general protection fault

Well, maybe your tests might be useful in the end. At the client-side you could vary the mount.cifs -o vers= to see whether your config changes allow negotiation of higher protocols without oopsing.. You might need to test with a big file though (mine were added up to over 10 Gb; which I was uploading with rsync to the windowes-share)

rob

brobr · 07-20-2018, 04:15 AM

Hi, I tested various dialect versions. At my work, from my slackware box with -current (4.14.55 or 56), no cifs-mount is possible with version 3 or over. With versions 2.0 or 2.1, or without any version given, mount works but rsync chokes immediately when trying to transfer files (So, not halfway or near the end). The general protection fault shows up in dmesg (see attached trace when trying with the 2.1 cifs-mount). After this, Thunar struggles and un-mounting the windows-share (as root) via umount needs the 'lazy' -l flag. Retrying another cifs-mount no longer works; a reboot is needed.

Hth

rob

Gnisho · 07-20-2018, 08:36 AM

Same issue here as well. Recently decided to look into ditching protocol version 1.0 due to potential issues and that MS wants to deprecate it anyway.

Using rsync to run backups from windows onto a slackware system. With shares mounted with vers=1.0, everything is fine. With 2.0, 2.1, or 3.0, a simple 'ls' fails to list an item or two, rsync misses items. Issue is the same on both 64-14.2 and 64-current (20180718). vers=3.11 not yet tested, mount.cifs fails with that option despite kernel having been recompiled to add that option. Figure I need to check documentation and maybe recompile cifs-utils. Maybe after my second cup of coffee this morning.

ivandi · 07-20-2018, 11:01 AM

Same here. Mounts fine, but the first write causes a segfault. Maybe something to do with these fixes. But I am too lazy to revert back to older kernel. Vers=1.0 works for now.

Cheers

Gnisho · 07-20-2018, 11:14 AM

More information in case it's helpful, am using provided kernels on both 14.2 (4.4.132) and current (4.15.56). Server end is Win10-1803

Also, using shipped SlackBuild, upgraded cifs-tools on -current from 6.7 to 6.8, with vers=3.11 mount still fails with "Resource temporarily unavailable."

Reverting to vers=1.0 for now.

kjhambrick · 07-20-2018, 12:26 PM

Thanks for the logs, brobr

Nice Laptop btw ... I am a Sager / Clevo man, myself

-- kjh

kjhambrick · 07-20-2018, 12:30 PM

Thanks for the Info Gnisho and ivandi ...

I also wondered about util-linux after seeing the new on in today's Slackware 14.2+current

-- kjh

brobr · 07-20-2018, 05:49 PM

Quote:

Originally Posted by kjhambrick

Thanks for the logs, brobr

Nice Laptop btw ... I am a Sager / Clevo man, myself

-- kjh

Thanks; it's a good piece of kit; at our side of the Atlantic there is an OK company where you can configure the specs before ordering; good service as well; they replaced the screen after brownish sediment started to accumulate...

kjhambrick · 07-21-2018, 11:07 AM

Baby Steps ...

I've got a Windows 7 VMWare Machine running on my Work Laptop ( win7u ).

All I use it for is Outlook and GoTo Meetings for Work.

The Laptop is running 4.4.142 GENERIC including the following CIFS-related configs:

Code:

# grep CIFS /boot/config

CONFIG_CIFS=m
# CONFIG_CIFS_STATS is not set
CONFIG_CIFS_WEAK_PW_HASH=y
# CONFIG_CIFS_UPCALL is not set
# CONFIG_CIFS_XATTR is not set
CONFIG_CIFS_DEBUG=y
# CONFIG_CIFS_DEBUG2 is not set
CONFIG_CIFS_DFS_UPCALL=y
CONFIG_CIFS_SMB2=y
CONFIG_CIFS_SMB311=y
CONFIG_CIFS_FSCACHE=y

I shared the entire win7u C-Drive and mounted it as root on my Laptop like so ( note the vers=2.1 option )

Code:

# mount -v -t cifs //172.16.162.137/c /mnt/win7u -o "rw,uid=root,vers=2.1,forceuid,dir_mode=0777,file_mode=0666,noserverino,credentials=/root/.smbcred,ip=172.16.162.137"
# df -H

Filesystem          Size  Used Avail Use% Mounted on
tmpfs                34M  1.1M   33M   4% /run
devtmpfs            8.4M     0  8.4M   0% /dev
/dev/sda3           899G  369G  485G  44% /
tmpfs                34G  254k   34G   1% /dev/shm
cgroup_root          34G     0   34G   0% /sys/fs/cgroup
/dev/sda2           1.1G  651M  303M  69% /boot
/dev/sdb2           904G  591G  267G  69% /home
/dev/sdd1           455G  136G  296G  32% /opt
cgmfs               103k     0  103k   0% /run/cgmanager/fs
//172.16.162.137/c  162G  126G   37G  78% /mnt/win7u

dmesg showed these two lines when I mounted /mnt/win7u

Code:

[ 3522.735657] FS-Cache: Loaded
[ 3522.737798] FS-Cache: Netfs 'cifs' registered for caching

Then I ran a couple read-from-win7u tests because the C-Drive ( only Drive ) on this VM is running low on space.

1. copy the largest win7u file that I can find to /dev/null on the linux box as 'me'.

NOTE: The test file is my Outlook .ost file so I closed Outlook on win7u because: 1) Outlook locks the file and 2) Outlook changes the file automatically as emails arrive.

Code:

$ ls -la '/mnt/win7u//Users/konrad/AppData/local/Microsoft/Outlook/me@example.com.ost'

-rw-rw-rw- 1 root root 48029451264 Jul 21 09:57 /mnt/win7u//Users/konrad/AppData/local/Microsoft/Outlook/me@example.com.ost

$ cat '/mnt/win7u//Users/konrad/AppData/local/Microsoft/Outlook/me@example.com.ost' |dd bs=1M of=/dev/null status=progress

47978512384 bytes (48 GB, 45 GiB) copied, 423.005 s, 113 MB/s  
65+353733 records in
65+353733 records out
48029451264 bytes (48 GB, 45 GiB) copied, 423.415 s, 113 MB/s

$ ls -la '/mnt/win7u//Users/konrad/AppData/local/Microsoft/Outlook/me@example.com.ost'
-rw-rw-rw- 1 root root 48029451264 Jul 21 09:57 /mnt/win7u//Users/konrad/AppData/local/Microsoft/Outlook/me@example.com.ost

That worked ... Try it again writing to a gzip'd local file this time

Code:

$ cat '/mnt/win7u//Users/konrad/AppData/local/Microsoft/Outlook/me@example.com.ost' |dd bs=1M status=progress |gzip -c > foo-file.gz

48024649728 bytes (48 GB, 45 GiB) copied, 1421 s, 33.8 MB/s     
1775+292054 records in
1775+292054 records out
48029451264 bytes (48 GB, 45 GiB) copied, 1421.16 s, 33.8 MB/s

$ ls -la foo-file.gz

-rw-rw-r-- 1 konrad users 13251777743 Jul 21 10:44 foo-file.gz

So ... did I get a good file ( yes, I did ) ?

This is the original file:

Code:

$ cat '/mnt/win7u//Users/konrad/AppData/local/Microsoft/Outlook/me@example.com.ost' |dd bs=1M status=progress |md5sum -

47939715072 bytes (48 GB, 45 GiB) copied, 413.006 s, 116 MB/s 
30+329951 records in
30+329951 records out
48029451264 bytes (48 GB, 45 GiB) copied, 413.858 s, 116 MB/s

600eeafe4c6430631afa3581d9f370aa  -

And this is the copy:

Code:

$gunzip -c < foo-file.gz |md5sum -

600eeafe4c6430631afa3581d9f370aa  -

Finally, clean up my mess:

Code:

$ rm foo-file.gz

And as root ...

Code:

# umount /mnt/win7u
# df -H
  
Filesystem      Size  Used Avail Use% Mounted on
tmpfs            34M  1.1M   33M   4% /run
devtmpfs        8.4M     0  8.4M   0% /dev
/dev/sda3       899G  369G  485G  44% /
tmpfs            34G  254k   34G   1% /dev/shm
cgroup_root      34G     0   34G   0% /sys/fs/cgroup
/dev/sda2       1.1G  651M  303M  69% /boot
/dev/sdb2       904G  591G  267G  69% /home
/dev/sdd1       455G  136G  296G  32% /opt
cgmfs           103k     0  103k   0% /run/cgmanager/fs

There were no additional messages in dmesg ...

Next up: write-to-Windows testing.

-- kjh

brobr · 07-21-2018, 06:49 PM

Hi Konrad. FYI, the CIFS section of the -current64 config-4.14.56:

Quote:

CONFIG_CIFS=m
# CONFIG_CIFS_STATS is not set
CONFIG_CIFS_WEAK_PW_HASH=y
CONFIG_CIFS_UPCALL=y
CONFIG_CIFS_XATTR=y
CONFIG_CIFS_POSIX=y
CONFIG_CIFS_ACL=y
# CONFIG_CIFS_DEBUG is not set
CONFIG_CIFS_DFS_UPCALL=y
# CONFIG_CIFS_SMB311 is not set
CONFIG_CIFS_FSCACHE=y

kjhambrick · 07-22-2018, 07:53 AM

Interesting info brobr.

Kernel 4.14.56 CIFS Docs are below my sig ... as ( I believe it was ) 55020 said, there is no longer a CONFIG_CIFS_SMB2 Variable.

I believe I read 'somewhere' that starting with 4.13.y that the default mount.cifs vers=2.0 ...

So another 4.4.142 + ( CONFIG_CIFS_SMB2=y ; CONFIG_CIFS_SMB311=y ) experiment.

I turned off SMB1 in Win7 ( see the attached picture for the Registry Key ).

Here is a handy little test script to mount my win7u Windows 7 share with varying option vers= settings ( ! YMWV ! ) :

Code:

#!/bin/sh
#
IPAddr="172.16.162.137"          # edit me !
Share="//${IPAddr}/c"            # edit me !
MtPt="/mnt/win7u"                # edit me !

Version="2.1"                    # Max SMB Version for Windows 7 is 2.1

[ $# -gt 0 ] && Version="$1"

mount -v -t cifs $Share $MtPt -o "rw,uid=root,vers=${Version},forceuid,dir_mode=0777,file_mode=0666,noserverino,credentials=/root/.smbcred,ip=$IPAddr"
exit $?

I CANNOT mount with option vers=1.0

Code:

# mount-win7u 1.0 ; r=$? ; [ "$r" = "0" ] && df /mnt/win7u && umount /mnt/win7u ; echo -e "\n# RetCode = $r" 

# invoking mount.cifs with option vers=1.0 ...

ip address 172.16.162.137 override specified
mount.cifs kernel mount options: ip=172.16.162.137,unc=\\172.16.162.137\c,vers=1.0,forceuid,dir_mode=0777,file_mode=0666,noserverino,uid=0,user=UUUUUUUU,pass=********
mount error(112): Host is down
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

# RetCode = 32

# NOTE:  dmesg -w says:

[81964.428320] CIFS VFS: cifs_mount failed w/return code = -112

I CAN mount with option vers=2.0

Code:

# mount-win7u 2.0 ; r=$? ; [ "$r" = "0" ] && df /mnt/win7u && umount /mnt/win7u ; echo -e "\n# RetCode = $r" 

# invoking mount.cifs with option vers=2.0 ...

ip address 172.16.162.137 override specified
mount.cifs kernel mount options: ip=172.16.162.137,unc=\\172.16.162.137\c,vers=2.0,forceuid,dir_mode=0777,file_mode=0666,noserverino,uid=0,user=UUUUUUUU,pass=********
Filesystem         1K-blocks      Used Available Use% Mounted on
//172.16.162.137/c 157283324 122097952  35185372  78% /mnt/win7u

# RetCode = 0

# NOTE that dmesg -w said NOTHING

I CAN mount with option vers=2.1

Code:

# mount-win7u 2.1 ; r=$? ; [ "$r" = "0" ] && df /mnt/win7u && umount /mnt/win7u ; echo -e "\n# RetCode = $r" 

# invoking mount.cifs with option vers=2.1 ...

ip address 172.16.162.137 override specified
mount.cifs kernel mount options: ip=172.16.162.137,unc=\\172.16.162.137\c,vers=2.1,forceuid,dir_mode=0777,file_mode=0666,noserverino,uid=0,user=UUUUUUUU,pass=********
Filesystem         1K-blocks      Used Available Use% Mounted on
//172.16.162.137/c 157283324 122097952  35185372  78% /mnt/win7u

# RetCode = 0

# NOTE that dmesg -w said NOTHING

But Windows 7 cannot do vers=3.0 or 3.11:

Code:

# mount-win7u 3.0 ; r=$? ; [ "$r" = "0" ] && df /mnt/win7u && umount /mnt/win7u ; echo -e "\n# RetCode = $r" 

# invoking mount.cifs with option vers=3.0 ...

ip address 172.16.162.137 override specified
mount.cifs kernel mount options: ip=172.16.162.137,unc=\\172.16.162.137\c,vers=3.0,forceuid,dir_mode=0777,file_mode=0666,noserverino,uid=0,user=UUUUUUUU,pass=********
mount error(95): Operation not supported
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

# RetCode = 32

# Note that dmesg -w said:

82119.413301] CIFS VFS: cifs_mount failed w/return code = -95

# -----------------------------------------------------------

# mount-win7u 3.11 ; r=$? ; [ "$r" = "0" ] && df /mnt/win7u && umount /mnt/win7u ; echo -e "\n# RetCode = $r" 

# invoking mount.cifs with option vers=3.11 ...

ip address 172.16.162.137 override specified
mount.cifs kernel mount options: ip=172.16.162.137,unc=\\172.16.162.137\c,vers=3.11,forceuid,dir_mode=0777,file_mode=0666,noserverino,uid=0,user=UUUUUUUU,pass=********
mount error(95): Operation not supported
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

# RetCode = 32

# Note that dmesg -w said:

[82174.950198] CIFS VFS: cifs_mount failed w/return code = -95

I'll add some Disk Space to win7u for some write tests and then move on to win10 ...

-- kjh

These are the 4.14.56 CIFS Kernel Configs

Code:

config CIFS
        tristate "SMB3 and CIFS support (advanced network filesystem)"
        depends on INET
        select NLS
        select CRYPTO
        select CRYPTO_MD4
        select CRYPTO_MD5
        select CRYPTO_SHA256
        select CRYPTO_CMAC
        select CRYPTO_HMAC
        select CRYPTO_ARC4
        select CRYPTO_AEAD2
        select CRYPTO_CCM
        select CRYPTO_ECB
        select CRYPTO_AES
        select CRYPTO_DES
        help
          This is the client VFS module for the SMB3 family of NAS protocols,
          as well as for earlier dialects such as SMB2.1, SMB2 and the
          Common Internet File System (CIFS) protocol.  CIFS was the successor
          to the original dialect, the Server Message Block (SMB) protocol, the
          native file sharing mechanism for most early PC operating systems.

          The SMB3 protocol is supported by most modern operating systems and
          NAS appliances (e.g. Samba, Windows 8, Windows 2012, MacOS).
          The older CIFS protocol was included in Windows NT4, 2000 and XP (and
          later) as well by Samba (which provides excellent CIFS and SMB3
          server support for Linux and many other operating systems). Limited
          support for OS/2 and Windows ME and similar very old servers is
          provided as well.

          The cifs module provides an advanced network file system client
          for mounting to SMB3 (and CIFS) compliant servers.  It includes
          support for DFS (hierarchical name space), secure per-user
          session establishment via Kerberos or NTLM or NTLMv2,
          safe distributed caching (oplock), optional packet
          signing, Unicode and other internationalization improvements.

          In general, the default dialects, SMB3 and later, enable better
          performance, security and features, than would be possible with CIFS.
          Note that when mounting to Samba, due to the CIFS POSIX extensions,
          CIFS mounts can provide slightly better POSIX compatibility
          than SMB3 mounts. SMB2/SMB3 mount options are also
          slightly simpler (compared to CIFS) due to protocol improvements.

          If you need to mount to Samba, Macs or Windows from this machine, say Y.

config CIFS_STATS
        bool "CIFS statistics"
        depends on CIFS
        help
          Enabling this option will cause statistics for each server share
          mounted by the cifs client to be displayed in /proc/fs/cifs/Stats

config CIFS_STATS2
        bool "Extended statistics"
        depends on CIFS_STATS
        help
          Enabling this option will allow more detailed statistics on SMB
          request timing to be displayed in /proc/fs/cifs/DebugData and also
          allow optional logging of slow responses to dmesg (depending on the
          value of /proc/fs/cifs/cifsFYI, see fs/cifs/README for more details).
          These additional statistics may have a minor effect on performance
          and memory utilization.

          Unless you are a developer or are doing network performance analysis
          or tuning, say N.

config CIFS_WEAK_PW_HASH
        bool "Support legacy servers which use weaker LANMAN security"
        depends on CIFS
        help
          Modern CIFS servers including Samba and most Windows versions
          (since 1997) support stronger NTLM (and even NTLMv2 and Kerberos)
          security mechanisms. These hash the password more securely
          than the mechanisms used in the older LANMAN version of the
          SMB protocol but LANMAN based authentication is needed to
          establish sessions with some old SMB servers.

          Enabling this option allows the cifs module to mount to older
          LANMAN based servers such as OS/2 and Windows 95, but such
          mounts may be less secure than mounts using NTLM or more recent
          security mechanisms if you are on a public network.  Unless you
          have a need to access old SMB servers (and are on a private
          network) you probably want to say N.  Even if this support
          is enabled in the kernel build, LANMAN authentication will not be
          used automatically. At runtime LANMAN mounts are disabled but
          can be set to required (or optional) either in
          /proc/fs/cifs (see fs/cifs/README for more detail) or via an
          option on the mount command. This support is disabled by
          default in order to reduce the possibility of a downgrade
          attack.

          If unsure, say N.

config CIFS_UPCALL
        bool "Kerberos/SPNEGO advanced session setup"
        depends on CIFS && KEYS
        select DNS_RESOLVER
        help
          Enables an upcall mechanism for CIFS which accesses userspace helper
          utilities to provide SPNEGO packaged (RFC 4178) Kerberos tickets
          which are needed to mount to certain secure servers (for which more
          secure Kerberos authentication is required). If unsure, say Y.

config CIFS_XATTR
        bool "CIFS extended attributes"
        depends on CIFS
        help
          Extended attributes are name:value pairs associated with inodes by
          the kernel or by users (see the attr(5) manual page, or visit
          <http://acl.bestbits.at/> for details).  CIFS maps the name of
          extended attributes beginning with the user namespace prefix
          to SMB/CIFS EAs. EAs are stored on Windows servers without the
          user namespace prefix, but their names are seen by Linux cifs clients
          prefaced by the user namespace prefix. The system namespace
          (used by some filesystems to store ACLs) is not supported at
          this time.

          If unsure, say Y.

config CIFS_POSIX
        bool "CIFS POSIX Extensions"
        depends on CIFS_XATTR
        help
          Enabling this option will cause the cifs client to attempt to
          negotiate a newer dialect with servers, such as Samba 3.0.5
          or later, that optionally can handle more POSIX like (rather
          than Windows like) file behavior.  It also enables
          support for POSIX ACLs (getfacl and setfacl) to servers
          (such as Samba 3.10 and later) which can negotiate
          CIFS POSIX ACL support.  If unsure, say N.

config CIFS_ACL
          bool "Provide CIFS ACL support"
          depends on CIFS_XATTR && KEYS
          help
            Allows fetching CIFS/NTFS ACL from the server.  The DACL blob
            is handed over to the application/caller.  See the man
            page for getcifsacl for more information.  If unsure, say Y.

config CIFS_DEBUG
        bool "Enable CIFS debugging routines"
        default y
        depends on CIFS
        help
           Enabling this option adds helpful debugging messages to
           the cifs code which increases the size of the cifs module.
           If unsure, say Y.
config CIFS_DEBUG2
        bool "Enable additional CIFS debugging routines"
        depends on CIFS_DEBUG
        help
           Enabling this option adds a few more debugging routines
           to the cifs code which slightly increases the size of
           the cifs module and can cause additional logging of debug
           messages in some error paths, slowing performance. This
           option can be turned off unless you are debugging
           cifs problems.  If unsure, say N.

config CIFS_DEBUG_DUMP_KEYS
        bool "Dump encryption keys for offline decryption (Unsafe)"
        depends on CIFS_DEBUG
        help
           Enabling this will dump the encryption and decryption keys
           used to communicate on an encrypted share connection on the
           console. This allows Wireshark to decrypt and dissect
           encrypted network captures. Enable this carefully.
           If unsure, say N.

config CIFS_DFS_UPCALL
          bool "DFS feature support"
          depends on CIFS && KEYS
          select DNS_RESOLVER
          help
            Distributed File System (DFS) support is used to access shares
            transparently in an enterprise name space, even if the share
            moves to a different server.  This feature also enables
            an upcall mechanism for CIFS which contacts userspace helper
            utilities to provide server name resolution (host names to
            IP addresses) which is needed for implicit mounts of DFS junction
            points. If unsure, say Y.

config CIFS_NFSD_EXPORT
          bool "Allow nfsd to export CIFS file system"
          depends on CIFS && BROKEN
          help
           Allows NFS server to export a CIFS mounted share (nfsd over cifs)

config CIFS_SMB311
        bool "SMB3.1.1 network file system support (Experimental)"
        depends on CIFS
        select CRYPTO_SHA512

        help
          This enables experimental support for the newest, SMB3.1.1, dialect.
          This dialect includes improved security negotiation features.
          If unsure, say N

config CIFS_FSCACHE
          bool "Provide CIFS client caching support"
          depends on CIFS=m && FSCACHE || CIFS=y && FSCACHE=y
          help
            Makes CIFS FS-Cache capable. Say Y here if you want your CIFS data
            to be cached locally on disk through the general filesystem cache
            manager. If unsure, say N.

brobr · 07-22-2018, 08:01 AM

Possibly the server I am connecting to at work runs windows 7 and not 8 or 10 which would explain that I could mount with cifs using dialect versions 2.0, 2.1 but not higher...