cifs: store password in tcon

Each tcon has its own password for share-level security. Store it in
the tcon and wipe it clean and free it when freeing the tcon. When
doing the tree connect with share-level security, use the tcon password
instead of the session password.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

cifs: have calc_lanman_hash take more granular args

We need to use this routine to encrypt passwords associated with the
tcon too. Don't assume that the password will be attached to the
smb_session.

Also, make some of the values in the lower encryption functions
const since they aren't changed.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

Some applications/subsystems require mandatory byte range locks
(as is used for Windows/DOS/OS2 etc). Sending advisory (posix style)
byte range lock requests (instead of mandatory byte range locks) can
lead to problems for these applications (which expect that other
clients be prevented from writing to portions of the file which
they have locked and are updating).  This mount option allows
mounting cifs with the new mount option "forcemand" (or
"forcemandatorylock") in order to have the cifs client use mandatory
byte range locks (ie SMB/CIFS/Windows/NTFS style locks) rather than
posix byte range lock requests, even if the server would support
posix byte range lock requests.  This has no effect if the server
does not support the CIFS Unix Extensions (since posix style locks
require support for the CIFS Unix Extensions), but for mounts
to Samba servers this can be helpful for Wine and applications
that require mandatory byte range locks.
Acked-by: NJeff Layton <jlayton@redhat.com>
CC: Alexander Bokovoy <ab@samba.org>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

In order to unify the smb_send routines, we need to reorganize the
routines that connect the sockets. Have ipv4_connect take a
TCP_Server_Info pointer and get the necessary fields from that.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

struct smb_vol is fairly large, it's probably best to kzalloc it...
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Clean up cifs_mount a bit by moving the code that creates new TCP
sessions into a separate function. Have that function search for an
existing socket and then create a new one if one isn't found.

Also reorganize the initializion of TCP_Server_Info a bit to prepare
for cleanup of the socket connection code.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The current code for setting the session serverName is IPv4-specific.
Allow it to be an IPv6 address as well. Use NIP* macros to set the
format.

This also entails increasing the length of the serverName field, so
declare a new macro for RFC1001 name length and use it in the
appropriate places.

Finally, drop the unicode_server_Name field from TCP_Server_Info since
it's not used. We can add it back later if needed, but for now it just
wastes memory.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Mutexes are preferred for single-holder semaphores...
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

cifsd can outlive the last cifs mount. We need to hold a module
reference until it exits to prevent someone from unplugging
the module until we're ready.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

set tcon->ses earlier

If the inital tree connect fails, we'll end up calling cifs_put_smb_ses
with a NULL pointer. Fix it by setting the tcon->ses earlier.
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Use a similar approach to the SMB session sharing. Add a list of tcons
attached to each SMB session. Move the refcount to non-atomic. Protect
all of the above with the cifs_tcp_ses_lock. Add functions to
properly find and put references to the tcons.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

We do this by abandoning the global list of SMB sessions and instead
moving to a per-server list. This entails adding a new list head to the
TCP_Server_Info struct. The refcounting for the cifsSesInfo is moved to
a non-atomic variable. We have to protect it by a lock anyway, so there's
no benefit to making it an atomic. The list and refcount are protected
by the global cifs_tcp_ses_lock.

The patch also adds a new routines to find and put SMB sessions and
that properly take and put references under the lock.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The code that allows these structs to be shared is extremely racy.
Disable the sharing of SMB and tcon structs for now until we can
come up with a way to do this that's race free.

We want to continue to share TCP sessions, however since they are
required for multiuser mounts. For that, implement a new (hopefully
race-free) scheme. Add a new global list of TCP sessions, and take
care to get a reference to it whenever we're dealing with one.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

We're currently declaring both a sockaddr_in and sockaddr6_in on the
stack, but we really only need storage for one of them. Declare a
sockaddr struct and cast it to the proper type. Also, eliminate the
protocolType field in the TCP_Server_Info struct. It's redundant since
we have a sa_family field in the sockaddr anyway.

We may need to revisit this if SCTP is ever implemented, but for now
this will simplify the code.

CIFS over IPv6 also has a number of problems currently. This fixes all
of them that I found. Eventually, it would be nice to move more of the
code to be protocol independent, but this is a start.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

In preparation for Jeff's big umount/mount fixes to remove the possibility of
various races in cifs mount and linked list handling of sessions, sockets and
tree connections, this patch cleans up some repetitive code in cifs_mount,
and addresses a problem with ses->status and tcon->tidStatus in which we
were overloading the "need_reconnect" state with other status in that
field.  So the "need_reconnect" flag has been broken out from those
two state fields (need reconnect was not mutually exclusive from some of the
other possible tid and ses states).  In addition, a few exit cases in
cifs_mount were cleaned up, and a problem with a tcon flag (for lease support)
was not being set consistently for the 2nd mount of the same share

CC: Jeff Layton <jlayton@redhat.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

When retrying kernel_recvmsg, reset iov_base and iov_len.

Note comment from Sridhar: "In the normal path, iov.iov_len is clearly set to 4. But i think you are
running into a case where kernel_recvmsg() is called via 'goto incomplete_rcv'
It happens if the previous call fails with EAGAIN.
If you want to call recvmsg() after EAGAIN failure, you need to reset iov."
Signed-off-by: NShirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

CIFS in some heavy stress conditions cifs could get EAGAIN
repeatedly in smb_send2 which led to repeated retries and eventually
failure of large writes which could lead to data corruption.

There are three changes that were suggested by various network
developers:

1) convert cifs from non-blocking to blocking tcp sendmsg
(we left in the retry on failure)
2) change cifs to not set sendbuf and rcvbuf size for the socket
(let tcp autotune the buffer sizes since that works much better
in the TCP stack now)
3) if we have a partial frame sent in smb_send2, mark the tcp
session as invalid (close the socket and reconnect) so we do
not corrupt the remaining part of the SMB with the beginning
of the next SMB.

This does not appear to hurt performance measurably and has
been run in various scenarios, but it definately removes
a corruption that we were seeing in some high stress
test cases.
Acked-by: NShirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

cifs: handle the TCP_Server_Info->tsk field more carefully

We currently handle the TCP_Server_Info->tsk field without any locking,
but with some half-measures to try and prevent races. These aren't
really sufficient though. When taking down cifsd, use xchg() to swap
the contents of the tsk field with NULL so we don't end up trying
to send it more than one signal. Also, don't allow cifsd to exit until
the signal is received if we expect one.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

fcntl(F_SETLEASE) currently is not exported by cifs (nor by local file
systems) so cifs grants leases based on how other local processes have
opened the file not by whether the file is cacheable (oplocked).  This
adds the check to make sure that the file is cacheable on the client
before checking whether we can grant the lease locally
(generic_setlease).  It also adds a mount option for cifs (locallease)
if the user wants to override this and try to grant leases even
if the server did not grant oplock.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

When cifs_demultiplex_thread was converted to a kthread based kernel
thread, great pains were taken to make it so that kthread_stop would be
used to bring it down. This just added unnecessary complexity since we
needed to use a signal anyway to break out of kernel_recvmsg.

Also, cifs_demultiplex_thread does a bit of cleanup as it's exiting, and
we need to be certain that this gets done. It's possible for a kthread
to exit before its main function is ever run if kthread_stop is called
soon after its creation. While I'm not sure that this is a real problem
with cifsd now, it could be at some point in the future if cifs_mount is
ever changed to bring down the thread quickly.

The upshot here is that using kthread_stop to bring down the thread just
adds extra complexity with no real benefit. This patch changes the code
to use the original method to bring down the thread, but still leaves it
so that the thread is actually started with kthread_run.

This seems to fix the deadlock caused by the reproducer in this bug
report:

https://bugzilla.samba.org/show_bug.cgi?id=5720Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Older samba server (eg. 3.0.24 from Debian etch) don't work correctly,
if DFS paths are used. Such server claim that they support DFS, but fail
to process some requests with DFS paths. Starting with Linux 2.6.26,
the cifs clients starts sending DFS paths in such situations, rendering
it unuseable with older samba servers.

The nodfs mount options forces a share to be used with non DFS paths,
even if the server claims, that it supports it.
Signed-off-by: NMartin Koegler <mkoegler@auto.tuwien.ac.at>
Acked-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NIgor Mammedov <niallain@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

cifs_setup_session references pSesInfo->server several times. That
pointer shouldn't change during the life of the function so grab it
once and store it in a local var. This makes the code look a little
cleaner too.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

Remove some long lines
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The global tcpSesAllocCount variable is an atomic already and doesn't
really need the extra locking around it. Remove the locking and just use
the atomic_inc_return and atomic_dec_return functions to make sure we
access it correctly.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

fs/cifs/cifssmb.c:3917:13: warning: incorrect type in assignment (different base types)
fs/cifs/cifssmb.c:3917:13:    expected bool [unsigned] [usertype] is_unicode
fs/cifs/cifssmb.c:3917:13:    got restricted __le16

The comment explains why __force is used here.
fs/cifs/connect.c:458:16: warning: cast to restricted __be32
fs/cifs/connect.c:458:16: warning: cast to restricted __be32
fs/cifs/connect.c:458:16: warning: cast to restricted __be32
fs/cifs/connect.c:458:16: warning: cast to restricted __be32
fs/cifs/connect.c:458:16: warning: cast to restricted __be32
fs/cifs/connect.c:458:16: warning: cast to restricted __be32
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Put CIFS sockets in their own class to avoid some lockdep warnings. CIFS
sockets are not exposed to user-space, and so are not subject to the
same deadlock scenarios.

A similar change was made a couple of years ago for RPC sockets in commit
ed07536e.

This patch should prevent lockdep false-positives like this one:

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.18-98.el5.jtltest.38.bz456320.1debug #1
-------------------------------------------------------
test5/2483 is trying to acquire lock:
 (sk_lock-AF_INET){--..}, at: [<ffffffff800270d2>] tcp_sendmsg+0x1c/0xb2f

but task is already holding lock:
 (&inode->i_alloc_sem){--..}, at: [<ffffffff8002e454>] notify_change+0xf5/0x2e0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&inode->i_alloc_sem){--..}:
       [<ffffffff800a817c>] __lock_acquire+0x9a9/0xadf
       [<ffffffff800a8a72>] lock_acquire+0x55/0x70
       [<ffffffff8002e454>] notify_change+0xf5/0x2e0
       [<ffffffff800a4e36>] down_write+0x3c/0x68
       [<ffffffff8002e454>] notify_change+0xf5/0x2e0
       [<ffffffff800e358d>] do_truncate+0x50/0x6b
       [<ffffffff8005197c>] get_write_access+0x40/0x46
       [<ffffffff80012cf1>] may_open+0x1d3/0x22e
       [<ffffffff8001bc81>] open_namei+0x2c6/0x6dd
       [<ffffffff800289c6>] do_filp_open+0x1c/0x38
       [<ffffffff800683ef>] _spin_unlock+0x17/0x20
       [<ffffffff800167a7>] get_unused_fd+0xf9/0x107
       [<ffffffff8001a704>] do_sys_open+0x44/0xbe
       [<ffffffff80060116>] system_call+0x7e/0x83
       [<ffffffffffffffff>] 0xffffffffffffffff

-> #2 (&sysfs_inode_imutex_key){--..}:
       [<ffffffff800a817c>] __lock_acquire+0x9a9/0xadf
       [<ffffffff8010f6df>] create_dir+0x26/0x1d7
       [<ffffffff800a8a72>] lock_acquire+0x55/0x70
       [<ffffffff8010f6df>] create_dir+0x26/0x1d7
       [<ffffffff800671c0>] mutex_lock_nested+0x104/0x29c
       [<ffffffff800a819d>] __lock_acquire+0x9ca/0xadf
       [<ffffffff8010f6df>] create_dir+0x26/0x1d7
       [<ffffffff8010fc67>] sysfs_create_dir+0x58/0x76
       [<ffffffff8015144c>] kobject_add+0xdb/0x198
       [<ffffffff801be765>] class_device_add+0xb2/0x465
       [<ffffffff8005a6ff>] kobject_get+0x12/0x17
       [<ffffffff80225265>] register_netdevice+0x270/0x33e
       [<ffffffff8022538c>] register_netdev+0x59/0x67
       [<ffffffff80464d40>] net_olddevs_init+0xb/0xac
       [<ffffffff80448a79>] init+0x1f9/0x2fc
       [<ffffffff80068885>] _spin_unlock_irq+0x24/0x27
       [<ffffffff80067f86>] trace_hardirqs_on_thunk+0x35/0x37
       [<ffffffff80061079>] child_rip+0xa/0x11
       [<ffffffff80068885>] _spin_unlock_irq+0x24/0x27
       [<ffffffff800606a8>] restore_args+0x0/0x30
       [<ffffffff80179a59>] acpi_ds_init_one_object+0x0/0x80
       [<ffffffff80448880>] init+0x0/0x2fc
       [<ffffffff8006106f>] child_rip+0x0/0x11
       [<ffffffffffffffff>] 0xffffffffffffffff

-> #1 (rtnl_mutex){--..}:
       [<ffffffff800a817c>] __lock_acquire+0x9a9/0xadf
       [<ffffffff8025acf8>] ip_mc_leave_group+0x23/0xb7
       [<ffffffff800a8a72>] lock_acquire+0x55/0x70
       [<ffffffff8025acf8>] ip_mc_leave_group+0x23/0xb7
       [<ffffffff800671c0>] mutex_lock_nested+0x104/0x29c
       [<ffffffff8025acf8>] ip_mc_leave_group+0x23/0xb7
       [<ffffffff802451b0>] do_ip_setsockopt+0x6d1/0x9bf
       [<ffffffff800a575e>] lock_release_holdtime+0x27/0x48
       [<ffffffff800a575e>] lock_release_holdtime+0x27/0x48
       [<ffffffff8006a85e>] do_page_fault+0x503/0x835
       [<ffffffff8012cbf6>] socket_has_perm+0x5b/0x68
       [<ffffffff80245556>] ip_setsockopt+0x22/0x78
       [<ffffffff8021c973>] sys_setsockopt+0x91/0xb7
       [<ffffffff800602a6>] tracesys+0xd5/0xdf
       [<ffffffffffffffff>] 0xffffffffffffffff

-> #0 (sk_lock-AF_INET){--..}:
       [<ffffffff800a5037>] print_stack_trace+0x59/0x68
       [<ffffffff800a8092>] __lock_acquire+0x8bf/0xadf
       [<ffffffff800a8a72>] lock_acquire+0x55/0x70
       [<ffffffff800270d2>] tcp_sendmsg+0x1c/0xb2f
       [<ffffffff80035466>] lock_sock+0xd4/0xe4
       [<ffffffff80096e91>] _local_bh_enable+0xcb/0xe0
       [<ffffffff800606a8>] restore_args+0x0/0x30
       [<ffffffff800270d2>] tcp_sendmsg+0x1c/0xb2f
       [<ffffffff80057540>] sock_sendmsg+0xf3/0x110
       [<ffffffff800a2bb6>] autoremove_wake_function+0x0/0x2e
       [<ffffffff800a10e4>] kernel_text_address+0x1a/0x26
       [<ffffffff8006f4e2>] dump_trace+0x211/0x23a
       [<ffffffff800a6d3d>] find_usage_backwards+0x5f/0x88
       [<ffffffff8840221a>] MD5Final+0xaf/0xc2 [cifs]
       [<ffffffff884032ec>] cifs_calculate_signature+0x55/0x69 [cifs]
       [<ffffffff8021d891>] kernel_sendmsg+0x35/0x47
       [<ffffffff883ff38e>] smb_send+0xa3/0x151 [cifs]
       [<ffffffff883ff5de>] SendReceive+0x1a2/0x448 [cifs]
       [<ffffffff800a812f>] __lock_acquire+0x95c/0xadf
       [<ffffffff883e758a>] CIFSSMBSetEOF+0x20d/0x25b [cifs]
       [<ffffffff883fa430>] cifs_set_file_size+0x110/0x3b7 [cifs]
       [<ffffffff883faa89>] cifs_setattr+0x3b2/0x6f6 [cifs]
       [<ffffffff8002e454>] notify_change+0xf5/0x2e0
       [<ffffffff8002e4a4>] notify_change+0x145/0x2e0
       [<ffffffff800e358d>] do_truncate+0x50/0x6b
       [<ffffffff8005197c>] get_write_access+0x40/0x46
       [<ffffffff80012cf1>] may_open+0x1d3/0x22e
       [<ffffffff8001bc81>] open_namei+0x2c6/0x6dd
       [<ffffffff800289c6>] do_filp_open+0x1c/0x38
       [<ffffffff800683ef>] _spin_unlock+0x17/0x20
       [<ffffffff800167a7>] get_unused_fd+0xf9/0x107
       [<ffffffff8001a704>] do_sys_open+0x44/0xbe
       [<ffffffff800602a6>] tracesys+0xd5/0xdf
       [<ffffffffffffffff>] 0xffffffffffffffff

other info that might help us debug this:

2 locks held by test5/2483:
 #0:  (&inode->i_mutex){--..}, at: [<ffffffff800e3582>] do_truncate+0x45/0x6b
 #1:  (&inode->i_alloc_sem){--..}, at: [<ffffffff8002e454>] notify_change+0xf5/0x2e0

stack backtrace:

Call Trace:
 [<ffffffff800a6a7b>] print_circular_bug_tail+0x65/0x6e
 [<ffffffff800a5037>] print_stack_trace+0x59/0x68
 [<ffffffff800a8092>] __lock_acquire+0x8bf/0xadf
 [<ffffffff800a8a72>] lock_acquire+0x55/0x70
 [<ffffffff800270d2>] tcp_sendmsg+0x1c/0xb2f
 [<ffffffff80035466>] lock_sock+0xd4/0xe4
 [<ffffffff80096e91>] _local_bh_enable+0xcb/0xe0
 [<ffffffff800606a8>] restore_args+0x0/0x30
 [<ffffffff800270d2>] tcp_sendmsg+0x1c/0xb2f
 [<ffffffff80057540>] sock_sendmsg+0xf3/0x110
 [<ffffffff800a2bb6>] autoremove_wake_function+0x0/0x2e
 [<ffffffff800a10e4>] kernel_text_address+0x1a/0x26
 [<ffffffff8006f4e2>] dump_trace+0x211/0x23a
 [<ffffffff800a6d3d>] find_usage_backwards+0x5f/0x88
 [<ffffffff8840221a>] :cifs:MD5Final+0xaf/0xc2
 [<ffffffff884032ec>] :cifs:cifs_calculate_signature+0x55/0x69
 [<ffffffff8021d891>] kernel_sendmsg+0x35/0x47
 [<ffffffff883ff38e>] :cifs:smb_send+0xa3/0x151
 [<ffffffff883ff5de>] :cifs:SendReceive+0x1a2/0x448
 [<ffffffff800a812f>] __lock_acquire+0x95c/0xadf
 [<ffffffff883e758a>] :cifs:CIFSSMBSetEOF+0x20d/0x25b
 [<ffffffff883fa430>] :cifs:cifs_set_file_size+0x110/0x3b7
 [<ffffffff883faa89>] :cifs:cifs_setattr+0x3b2/0x6f6
 [<ffffffff8002e454>] notify_change+0xf5/0x2e0
 [<ffffffff8002e4a4>] notify_change+0x145/0x2e0
 [<ffffffff800e358d>] do_truncate+0x50/0x6b
 [<ffffffff8005197c>] get_write_access+0x40/0x46
 [<ffffffff80012cf1>] may_open+0x1d3/0x22e
 [<ffffffff8001bc81>] open_namei+0x2c6/0x6dd
 [<ffffffff800289c6>] do_filp_open+0x1c/0x38
 [<ffffffff800683ef>] _spin_unlock+0x17/0x20
 [<ffffffff800167a7>] get_unused_fd+0xf9/0x107
 [<ffffffff8001a704>] do_sys_open+0x44/0xbe
 [<ffffffff800602a6>] tracesys+0xd5/0xdf
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

Samba now supports transport encryption on particular exports
(mounted tree ids can be encrypted for servers which support the
unix extensions).  This adds parsing support to cifs mount
option parsing for this.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Fixup GetDFSRefer to prepare for cleanup of SMB response processing
Fix build warning in link.c
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Some versions of Samba (3.2-pre e.g.) are stricter about checking to make sure that
paths in DFS name spaces are sent in the form \\server\share\dir\subdir ...
instead of \dir\subdir
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NSteve French <sfrench@us.ibm.com>

when unix extensions and cifsacl support are disabled. These
permissions changes are "ephemeral" however. They are lost whenever
a share is mounted and unmounted, or when memory pressure forces
the inode out of the cache.

Because of this, we'd like to introduce a behavior change to make
CIFS behave more like local DOS/Windows filesystems. When unix
extensions and cifsacl support aren't enabled, then don't silently
ignore changes to permission bits that can't be reflected on the
server.

Still, there may be people relying on the current behavior for
certain applications. This patch adds a new "dynperm" (and a
corresponding "nodynperm") mount option that will be intended
to make the client fall back to legacy behavior when setting
these modes.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

cifs_demultiplex_thread can exit under several conditions:

1) if it's signaled
2) if there's a problem with session setup
3) if kthread_stop is called on it

The first two are problems. If kthread_stop is called on the thread,
there is no guarantee that it will still be up. We need to have the
thread stay up until kthread_stop is called on it.

One option would be to not even try to tear things down until after
kthread_stop is called. However, in the case where there is a problem
setting up the session, there's no real reason to try continuing the
loop.

This patch allows the thread to clean up and prepare for exit under all
three conditions, but it has the thread go to sleep until kthread_stop
is called. This allows us to simplify the shutdown code somewhat since
we can be reasonably sure that the thread won't exit after being
signaled but before kthread_stop is called.

It also removes the places where the thread itself set the tsk variable
since it appeared that it could have a potential race where the thread
might never be shut down.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Clean up cifs_setattr a bit by adding a local inode pointer, and
changing all of the direntry->d_inode references to it. This also adds a
bit of micro-optimization. d_inode shouldn't change over the life of
this function, so we only need to dereference it once.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

This patch cleans up cifs_find_tcp_session so it become
less indented. Also the error of skipping IPv6 matched
addresses fixed.
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>