We use cifs_tcp_ses_lock to protect a lot of things.
Not only does it protect the lists of connections, sessions,
tree connects, open file lists, etc., we also use it to
protect some fields in each of it's entries.
In this case, cifs_mark_ses_for_reconnect takes the
cifs_tcp_ses_lock to traverse the lists, and then calls
cifs_update_iface. However, that can end up calling
cifs_put_tcp_session, which picks up the same lock again.
Avoid this by taking a ref for the session, drop the lock,
and then call update iface.
Also, in cifs_update_iface, avoid nested locking of iface_lock
and chan_lock, as much as possible. When unavoidable, we need
to pick iface_lock first.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Going forward, the plan is to periodically query the server
for it's interfaces (when multichannel is enabled).
This change allows checking for inactive interfaces during
reconnect, and reconnect to a new interface if necessary.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
A server's published interface list can change over time, and needs
to be updated. We've storing iface_list as a simple array, which
makes it difficult to manipulate an existing list.
With this change, iface_list is modified into a linked list of
interfaces, which is kept sorted by speed.
Also added a reference counter for an iface entry, so that each
channel can maintain a backpointer to the iface and drop it
easily when needed.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
cifs_ses_get_chan_index gets the index for a given server pointer.
When a match is not found, we warn about a possible bug.
However, printing details about the non-matching server could be
more useful to debug here.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently, the secondary channels of a multichannel session
also get hostname populated based on the info in primary channel.
However, this will end up with a wrong resolution of hostname to
IP address during reconnect.
This change fixes this by not populating hostname info for all
secondary channels.
Fixes: 5112d80c16 ("cifs: populate server_hostname for extra channels")
Cc: stable@vger.kernel.org
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The srv_mutex is used during writeback so cifs should ensure that
allocations done when that mutex is held are done with GFP_NOFS, to
avoid having direct reclaim ending up waiting for the same mutex and
causing a deadlock. This is detected by lockdep with the splat below:
======================================================
WARNING: possible circular locking dependency detected
5.18.0 #70 Not tainted
------------------------------------------------------
kswapd0/49 is trying to acquire lock:
ffff8880195782e0 (&tcp_ses->srv_mutex){+.+.}-{3:3}, at: compound_send_recv
but task is already holding lock:
ffffffffa98e66c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
fs_reclaim_acquire
kmem_cache_alloc_trace
__request_module
crypto_alg_mod_lookup
crypto_alloc_tfm_node
crypto_alloc_shash
cifs_alloc_hash
smb311_crypto_shash_allocate
smb311_update_preauth_hash
compound_send_recv
cifs_send_recv
SMB2_negotiate
smb2_negotiate
cifs_negotiate_protocol
cifs_get_smb_ses
cifs_mount
cifs_smb3_do_mount
smb3_get_tree
vfs_get_tree
path_mount
__x64_sys_mount
do_syscall_64
entry_SYSCALL_64_after_hwframe
-> #0 (&tcp_ses->srv_mutex){+.+.}-{3:3}:
__lock_acquire
lock_acquire
__mutex_lock
mutex_lock_nested
compound_send_recv
cifs_send_recv
SMB2_write
smb2_sync_write
cifs_write
cifs_writepage_locked
cifs_writepage
shrink_page_list
shrink_lruvec
shrink_node
balance_pgdat
kswapd
kthread
ret_from_fork
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&tcp_ses->srv_mutex);
lock(fs_reclaim);
lock(&tcp_ses->srv_mutex);
*** DEADLOCK ***
1 lock held by kswapd0/49:
#0: ffffffffa98e66c0 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat
stack backtrace:
CPU: 2 PID: 49 Comm: kswapd0 Not tainted 5.18.0 #70
Call Trace:
<TASK>
dump_stack_lvl
dump_stack
print_circular_bug.cold
check_noncircular
__lock_acquire
lock_acquire
__mutex_lock
mutex_lock_nested
compound_send_recv
cifs_send_recv
SMB2_write
smb2_sync_write
cifs_write
cifs_writepage_locked
cifs_writepage
shrink_page_list
shrink_lruvec
shrink_node
balance_pgdat
kswapd
kthread
ret_from_fork
</TASK>
Fix this by using the memalloc_nofs_save/restore APIs around the places
where the srv_mutex is held. Do this in a wrapper function for the
lock/unlock of the srv_mutex, and rename the srv_mutex to avoid missing
call sites in the conversion.
Note that there is another lockdep warning involving internal crypto
locks, which was masked by this problem and is visible after this fix,
see the discussion in this thread:
https://lore.kernel.org/all/20220523123755.GA13668@axis.com/
Link: https://lore.kernel.org/r/CANT5p=rqcYfYMVHirqvdnnca4Mo+JQSw5Qu12v=kPfpk5yhhmg@mail.gmail.com/
Reported-by: Shyam Prasad N <nspmangalore@gmail.com>
Suggested-by: Lars Persson <larper@axis.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Some older servers seem to require the workstation name during ntlmssp
to be at most 15 chars (RFC1001 name length), so truncate it before
sending when using insecure dialects.
Link: https://lore.kernel.org/r/e6837098-15d9-acb6-7e34-1923cf8c6fe1@winds.org
Reported-by: Byron Stanoszek <gandalf@winds.org>
Tested-by: Byron Stanoszek <gandalf@winds.org>
Fixes: 49bd49f983 ("cifs: send workstation name during ntlmssp session setup")
Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
After allowing channels to reconnect in parallel, it now
becomes important to take care that multiple processes do not
call negotiate/session setup in parallel on the same channel.
This change avoids that by marking a channel as "in_reconnect".
During session setup if the channel in question has this flag
set, we return immediately.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When mounting with SMB2.1 or earlier, even with nomultichannel, we
log the confusing warning message:
"CIFS: VFS: multichannel is not supported on this protocol version, use 3.0 or above"
Fix this so that we don't log this unless they really are trying
to mount with multichannel.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215608
Reported-by: Kim Scarborough <kim@scarborough.kim>
Cc: stable@vger.kernel.org # 5.11+
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Set workstation_name from the master_tcon for multiuser mounts.
Just in case, protect size_of_ntlmssp_blob against a NULL workstation_name.
Fixes: 49bd49f983 ("cifs: send workstation name during ntlmssp session setup")
Cc: stable@vger.kernel.org # 5.16
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Ryan Bair <ryandbair@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
For improved debugging it can be helpful to send version information
as other clients do during NTLMSSP negotiation. See protocol document
MS-NLMP section 2.2.1.1
Set the major and minor versions based on the kernel version, and the
BuildNumber based on the internal cifs.ko module version number,
and following the recommendation in the protocol documentation
(MS-NLMP section 2.2.10) we set the NTLMRevisionCurrent field to 15.
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Recent restructuring of cifs_reconnect introduced a helper func
named cifs_ses_mark_for_reconnect, which updates the state of tcp
session for all the channels of a session for reconnect.
However, this does not update the session state and chans_need_reconnect
bitmask. This change fixes that.
Also, cifs_mark_tcp_sess_for_reconnect should mark set the bitmask
for all channels when the whole session is marked for reconnect.
Fixed that here too.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The status of tcp session, smb session and tcon have the
same flow, irrespective of the SMB version used. Hence
these status checks and updates should happen in the
version independent callers of these commands.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
A spin lock called chan_lock was introduced recently.
But not all accesses were protected. Doing that with
this change.
To make sure that a channel is not freed when in use,
we need to introduce a ref count. But today, we don't
ever free channels.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Recent changes to multichannel required some adjustments in
the way connection states transitioned during/after reconnect.
Also some minor fixes:
1. A pending switch of GlobalMid_Lock to cifs_tcp_ses_lock
2. Relocations of the code that logs reconnect
3. Changed some code in allocate_mid to suit the new scheme
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Eliminate the follow smatch warning:
fs/cifs/sess.c:1581 sess_auth_rawntlmssp_authenticate() warn:
inconsistent indenting
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
One of my previous fixes:
cifs: send workstation name during ntlmssp session setup
...changed the prototype of build_ntlmssp_negotiate_blob
from being allocated by the caller to being allocated within
the function. The caller needs to free this object too.
While SMB2 version of the caller did it, I forgot to free
for the SMB1 version. Fixing that here.
Fixes: 49bd49f983 ("cifs: send workstation name during ntlmssp session setup")
Cc: stable@vger.kernel.org # 5.16
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
If functions like cifs_negotiate_protocol, cifs_setup_session,
cifs_tree_connect are called in parallel on different channels,
each of these will be execute the requests. This maybe unnecessary
in some cases, and only the first caller may need to do the work.
This is achieved by having more states for the tcp/smb/tcon session
status fields. And tracking the state of reconnection based on the
state machine.
For example:
for tcp connections:
CifsNew/CifsNeedReconnect ->
CifsNeedNegotiate ->
CifsInNegotiate ->
CifsNeedSessSetup ->
CifsInSessSetup ->
CifsGood
for smb sessions:
CifsNew/CifsNeedReconnect ->
CifsGood
for tcon:
CifsNew/CifsNeedReconnect ->
CifsInFilesInvalidate ->
CifsNeedTcon ->
CifsInTcon ->
CifsGood
If any channel reconnect sees that it's in the middle of
transition to CifsGood, then they can skip the function.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
While checking/updating status for tcp ses, smb ses or tcon,
we take GlobalMid_Lock. This doesn't make any sense.
Replaced it with cifs_tcp_ses_lock.
Ideally, we should take a spin lock per struct.
But since tcp ses, smb ses and tcon objects won't add up to a lot,
I think there should not be too much contention.
Also, in few other places, these are checked without locking.
Added locking for these.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
chan_count keeps track of the total number of channels.
Since at least the primary channel will always be connected,
this value can never go below 1. Warn if that happens.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
We use the concept of "binding" when one of the secondary channel
is in the process of connecting/reconnecting to the server. Till this
binding process completes, and the channel is bound to an existing session,
we redirect traffic from other established channels on the binding channel,
effectively blocking all traffic till individual channels get reconnected.
With my last set of commits, we can get rid of this binding serialization.
We now have a bitmap of connection states for each channel. We will use
this bitmap instead for tracking channel status.
Having a bitmap also now enables us to keep the session alive, as long
as even a single channel underneath is alive.
Unfortunately, this also meant that we need to supply the tcp connection
info for the channel during all negotiate and session setup functions.
These changes have resulted in a slightly bigger code churn.
However, I expect perf and robustness improvements in the mchan scenario
after this change.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
We needed a way to identify the channels under the smb session
which are in reconnect, so that the traffic to other channels
can continue. So I replaced the bool need_reconnect with
a bitmask identifying all the channels that need reconnection
(named chans_need_reconnect). When a channel needs reconnection,
the bit corresponding to the index of the server in ses->chans
is used to set this bitmask. Checking if no channels or all
the channels need reconnect then becomes very easy.
Also wrote some helper macros for checking and setting the bits.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Warn on the lack of key exchange during NTLMSSP authentication rather
than aborting it as there are some servers that do not set it in
CHALLENGE message.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Recently, a new field got added to the smb3_fs_context struct
named server_hostname. While creating extra channels, pick up
this field from primary channel.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Use new cifs_ses_mark_for_reconnect() helper to mark all session
channels for reconnect instead of duplicating it in different places.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
It is better to print debug messages outside of the chan_lock
spinlock where possible.
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Addresses-Coverity: 1493854 ("Thread deadlock")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Today, we don't have any way to get the smb session for any
of the secondary channels. Introducing a pointer to the primary
server from server struct of any secondary channel. The value will
be NULL for the server of the primary channel. This will enable us
to get the smb session for any channel.
This will be needed for some of the changes that I'm planning
to make soon.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Introducing a new spin lock to protect all the channel related
fields in a cifs_ses struct. This lock should be taken
whenever dealing with the channel fields, and should be held
only for very short intervals which will not sleep.
Currently, all channel related fields in cifs_ses structure
are protected by session_mutex. However, this mutex is held for
long periods (sometimes while waiting for a reply from server).
This makes the codepath quite tricky to change.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
During the ntlmssp session setup (authenticate phases)
send the client workstation info. This can make debugging easier on
servers.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
checkpatch complains about source files with filenames (e.g. in
these cases just below the SPDX header in comments at the top of
various files in fs/cifs). It also is helpful to change this now
so will be less confusing when the parent directory is renamed
e.g. from fs/cifs to fs/smb_client (or fs/smbfs)
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
for SMB1.
This removes the dependency to DES.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
smb_buf is allocated by small_smb_init_no_tc(), and buf type is
CIFS_SMALL_BUFFER, so we should use cifs_small_buf_release() to
release it in failed path.
Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Add SPDX license identifier and replace license boilerplate.
Corrects various checkpatch errors with the older format for
noting the LGPL license.
Signed-off-by: Steve French <stfrench@microsoft.com>
Use %pI6 for IPv6 addresses
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
We were ignoring CAP_MULTI_CHANNEL in the server response - if the
server doesn't support multichannel we should not be attempting it.
See MS-SMB2 section 3.2.5.2
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-By: Tom Talpey <tom@talpey.com>
Cc: <stable@vger.kernel.org> # v5.8+
Signed-off-by: Steve French <stfrench@microsoft.com>
With multichannel, operations like the queries
from "ls -lR" can cause all credits to be used and
errors to be returned since max_credits was not
being set correctly on the secondary channels and
thus the client was requesting 0 credits incorrectly
in some cases (which can lead to not having
enough credits to perform any operation on that
channel).
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
CC: <stable@vger.kernel.org> # v5.8+
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
ses->serverName is not the server name, but the string form
of the ip address of the server. Change the name to ip_addr
to avoid confusion (and fix the array length to match
maximum length of ipv6 address).
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Only load/unload local_nls from cifs_sb and just make the ctx
contain a pointer to cifs_sb->ctx.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
See Documentation/filesystems/mount_api.rst for details on new mount API
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Harmonize and change all such variables to 'ctx', where possible.
No changes to actual logic.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break/goto statements instead of
just letting the code fall through to the next case.
Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Convert cpu_to_be32(be32_to_cpu(E1) + E2) to use be32_add_cpu().
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Remove the superfuous break, as there is a 'return' before it.
Signed-off-by: Liao Pingfang <liao.pingfang@zte.com.cn>
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Steve French <stfrench@microsoft.com>
first steps in trying to make channels properly reconnect.
* add cifs_ses_find_chan() function to find the enclosing cifs_chan
struct it belongs to
* while we have the session lock and are redoing negprot and
sess.setup in smb2_reconnect() redo the binding of channels.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Add a cifs_chan pointer in struct cifs_ses that points to the channel
currently being bound if ses->binding is true.
Previously it was always the channel past the established count.
This will make reconnecting (and rebinding) a channel easier later on.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Use pr_fmt to standardize all logging for fs/cifs.
Some logging output had no CIFS: specific prefix.
Now all output has one of three prefixes:
o CIFS:
o CIFS: VFS:
o Root-CIFS:
Miscellanea:
o Convert printks to pr_<level>
o Neaten macro definitions
o Remove embedded CIFS: prefixes from formats
o Convert "illegal" to "invalid"
o Coalesce formats
o Add missing '\n' format terminations
o Consolidate multiple cifs_dbg continuations into single calls
o More consistent use of upper case first word output logging
o Multiline statement argument alignment and wrapping
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
When no interfaces are returned by the server we cannot open multiple
channels. Make it more obvious by reporting that to the user at the
VFS log level.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
iface[0] was accessed regardless of the count value and without
locking.
* check count before accessing any ifaces
* make copy of iface list (it's a simple POD array) and use it without
locking.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
