In order to scale down the channels, the following sequence
of operations happen:
1. server struct is marked for terminate
2. the channel is deallocated in the ses->chans array
3. at a later point the cifsd thread actually terminates the server
Between 2 and 3, there can be calls to find the channel for
a server struct. When that happens, there can be an ugly warning
that's logged. But this is expected.
So this change does two things:
1. in cifs_ses_get_chan_index, if server->terminate is set, return
2. always make sure server->terminate is set with chan_lock held
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Return statement was not needed at end of cifs_chan_update_iface
Suggested-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Signed-off-by: Steve French <stfrench@microsoft.com>
The return values for cifs_chan_update_iface() didn't match what the
documentation said and nothing was checking them anyway. Just make it
a void function.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
We return early if "iface" is NULL so there is no need to check here.
Delete those checks.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Recently, cifs_chan_update_iface was modified to not
remove an iface if a suitable replacement was not found.
With that, there were two conditionals that were exactly
the same. This change removes that extra condition check.
Also, fixed a logging in the same function to indicate
the correct message.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs_chan_update_iface is meant to check and update the server
interface used for a channel when the existing server interface
is no longer available.
So far, this handler had the code to remove an interface entry
even if a new candidate interface is not available. Allowing
this leads to several corner cases to handle.
This change makes the logic much simpler by not deallocating
the current channel interface entry if a new interface is not
found to replace it with.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
We were deferencing iface after it has been released. Fix is to
release after all dereference instances have been encountered.
Signed-off-by: Ritvik Budhiraja <rbudhiraja@microsoft.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/r/202311110815.UJaeU3Tt-lkp@intel.com/
Signed-off-by: Steve French <stfrench@microsoft.com>
The code to handle the case of server disabling multichannel
was picking iface_lock with chan_lock held. This goes against
the lock ordering rules, as iface_lock is a higher order lock
(even if it isn't so obvious).
This change fixes the lock ordering by doing the following in
that order for each secondary channel:
1. store iface and server pointers in local variable
2. remove references to iface and server in channels
3. unlock chan_lock
4. lock iface_lock
5. dec ref count for iface
6. unlock iface_lock
7. dec ref count for server
8. lock chan_lock again
Since this function can only be called in smb2_reconnect, and
that cannot be called by two parallel processes, we should not
have races due to dropping chan_lock between steps 3 and 8.
Fixes: ee1d21794e ("cifs: handle when server stops supporting multichannel")
Reported-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When a server stops supporting multichannel, we will
keep attempting reconnects to the secondary channels today.
Avoid this by freeing extra channels when negotiate
returns no multichannel support.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Minor cleanup of style issues found by checkpatch
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The only reason why cifs_sb gets passed today to cifs_try_adding_channels
is to pass the local_nls field for the new channels and binding session.
However, the ses struct already has local_nls field that is setup during
the first cifs_setup_session. So there is no need to pass cifs_sb.
This change removes cifs_sb from the arg list for this and the functions
that it calls and uses ses->local_nls instead.
Cc: stable@vger.kernel.org
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The refcounting of server interfaces should account
for the primary channel too. Although this is not
strictly necessary, doing so will account for the primary
channel in DebugData.
Cc: stable@vger.kernel.org
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Today, if the server interfaces RSS capable, we simply
choose the fastest interface to setup a channel. This is not
a scalable approach, and does not make a lot of attempt to
distribute the connections.
This change does a weighted distribution of channels across
all the available server interfaces, where the weight is
a function of the advertised interface speed.
Also make sure that we don't mix rdma and non-rdma for channels.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
So far, SMB multichannel could only scale up, but not
scale down the number of channels. In this series of
patch, we now allow the client to deal with the case
of multichannel disabled on the server when the share
is mounted. With that change, we now need the ability
to scale down the channels.
This change allows the client to deal with cases of
missing channels more gracefully.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
If the mount command has specified multichannel as a mount option,
but multichannel is found to be unsupported by the server at the time
of mount, we set chan_max to 1. Which means that the user needs to
remount the share if the server starts supporting multichannel.
This change removes this reset. What it means is that if the user
specified multichannel or max_channels during mount, and at this
time, multichannel is not supported, but the server starts supporting
it at a later point, the client will be capable of scaling out the
number of channels.
Cc: stable@vger.kernel.org
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The NTLM authenticate message currently sets the NTLMSSP_NEGOTIATE_VERSION
flag but does not populate the VERSION structure. This commit fixes this
bug by ensuring that the flag is set and the version details are included
in the message.
Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Since older dialects such as CIFS do not support multichannel
the macro CIFS_SERVER_IS_CHAN can be confusing (it requires SMB 3
or later) so shorten its name to "SERVER_IS_CHAN"
Suggested-by: Tom Talpey <tom@talpey.com>
Acked-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Clang warns about exceeded stack frame size
fs/smb/client/sess.c:160:5: warning: stack frame size (1368) exceeds
limit (1024) in 'cifs_try_adding_channels' [-Wframe-larger-than]
It turns out that cifs_ses_add_channel() got inlined into
cifs_try_adding_channels() which had a stack-allocated variable @ctx
of 624 bytes in size. Fix this by making it heap-allocated.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307270640.5ODmPwDl-lkp@intel.com/
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The NTLMSSP_NEGOTIATE_VERSION flag only needs to be sent during
the NTLMSSP NEGOTIATE (not the AUTH) request, so filter it out for
NTLMSSP AUTH requests. See MS-NLMP 2.2.1.3
This fixes a problem found by the gssntlmssp server.
Link: https://github.com/gssapi/gss-ntlmssp/issues/95
Fixes: 52d005337b ("smb3: send NTLMSSP version information")
Acked-by: Roy Shterman <roy.shterman@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:
fs/cifs --> fs/smb/client
fs/ksmbd --> fs/smb/server
fs/smbfs_common --> fs/smb/common
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
