When reconnect happens Mid queue can be corrupted when both
demultiplex and offload thread try to dequeue the MID from the
pending list.

These patches address a problem found during decryption offload:
         CIFS: VFS: trying to dequeue a deleted mid
that could cause a refcount use after free:
         Workqueue: smb3decryptd smb2_decrypt_offload [cifs]
Signed-off-by: NRohith Surabattula <rohiths@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org> #5.4+
Signed-off-by: NSteve French <stfrench@microsoft.com>

cifs_reconnect needs to be called only from demultiplex thread.
skip cifs_reconnect in offload thread. So, cifs_reconnect will be
called by demultiplex thread in subsequent request.

These patches address a problem found during decryption offload:
     CIFS: VFS: trying to dequeue a deleted mid
that can cause a refcount use after free:

[ 1271.389453] Workqueue: smb3decryptd smb2_decrypt_offload [cifs]
[ 1271.389456] RIP: 0010:refcount_warn_saturate+0xae/0xf0
[ 1271.389457] Code: fa 1d 6a 01 01 e8 c7 44 b1 ff 0f 0b 5d c3 80 3d e7 1d 6a 01 00 75 91 48 c7 c7 d8 be 1d a2 c6 05 d7 1d 6a 01 01 e8 a7 44 b1 ff <0f> 0b 5d c3 80 3d c5 1d 6a 01 00 0f 85 6d ff ff ff 48 c7 c7 30 bf
[ 1271.389458] RSP: 0018:ffffa4cdc1f87e30 EFLAGS: 00010286
[ 1271.389458] RAX: 0000000000000000 RBX: ffff9974d2809f00 RCX: ffff9974df898cc8
[ 1271.389459] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff9974df898cc0
[ 1271.389460] RBP: ffffa4cdc1f87e30 R08: 0000000000000004 R09: 00000000000002c0
[ 1271.389460] R10: 0000000000000000 R11: 0000000000000001 R12: ffff9974b7fdb5c0
[ 1271.389461] R13: ffff9974d2809f00 R14: ffff9974ccea0a80 R15: ffff99748e60db80
[ 1271.389462] FS:  0000000000000000(0000) GS:ffff9974df880000(0000) knlGS:0000000000000000
[ 1271.389462] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1271.389463] CR2: 000055c60f344fe4 CR3: 0000001031a3c002 CR4: 00000000003706e0
[ 1271.389465] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1271.389465] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1271.389466] Call Trace:
[ 1271.389483]  cifs_mid_q_entry_release+0xce/0x110 [cifs]
[ 1271.389499]  smb2_decrypt_offload+0xa9/0x1c0 [cifs]
[ 1271.389501]  process_one_work+0x1e8/0x3b0
[ 1271.389503]  worker_thread+0x50/0x370
[ 1271.389504]  kthread+0x12f/0x150
[ 1271.389506]  ? process_one_work+0x3b0/0x3b0
[ 1271.389507]  ? __kthread_bind_mask+0x70/0x70
[ 1271.389509]  ret_from_fork+0x22/0x30
Signed-off-by: NRohith Surabattula <rohiths@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org> #5.4+
Signed-off-by: NSteve French <stfrench@microsoft.com>

kmemleak reported a memory leak allocated in query_info() when cifs is
working with modefromsid.

  backtrace:
    [<00000000aeef6a1e>] slab_post_alloc_hook+0x58/0x510
    [<00000000b2f7a440>] __kmalloc+0x1a0/0x390
    [<000000006d470ebc>] query_info+0x5b5/0x700 [cifs]
    [<00000000bad76ce0>] SMB2_query_acl+0x2b/0x30 [cifs]
    [<000000001fa09606>] get_smb2_acl_by_path+0x2f3/0x720 [cifs]
    [<000000001b6ebab7>] get_smb2_acl+0x75/0x90 [cifs]
    [<00000000abf43904>] cifs_acl_to_fattr+0x13b/0x1d0 [cifs]
    [<00000000a5372ec3>] cifs_get_inode_info+0x4cd/0x9a0 [cifs]
    [<00000000388e0a04>] cifs_revalidate_dentry_attr+0x1cd/0x510 [cifs]
    [<0000000046b6b352>] cifs_getattr+0x8a/0x260 [cifs]
    [<000000007692c95e>] vfs_getattr_nosec+0xa1/0xc0
    [<00000000cbc7d742>] vfs_getattr+0x36/0x40
    [<00000000de8acf67>] vfs_statx_fd+0x4a/0x80
    [<00000000a58c6adb>] __do_sys_newfstat+0x31/0x70
    [<00000000300b3b4e>] __x64_sys_newfstat+0x16/0x20
    [<000000006d8e9c48>] do_syscall_64+0x37/0x80

This patch add missing kfree for pntsd when mounting modefromsid option.

Cc: Stable <stable@vger.kernel.org> # v5.4+
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

To 2.29
Signed-off-by: NSteve French <stfrench@microsoft.com>

Add some structures and defines that were recently added to
the protocol documentation (see MS-FSCC sections 2.3.29-2.3.34).
Signed-off-by: NSteve French <stfrench@microsoft.com>

Fix two unused variables in commit
"add support for stat of WSL reparse points for special file types"
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

This is needed so when mounting to Windows we do not
misinterpret various special files created by Linux (WSL) as symlinks.
An earlier patch addressed readdir.  This patch fixes stat (getattr).

With this patch:
  File: /mnt1/char
  Size: 0          Blocks: 0          IO Block: 16384  character special file
Device: 34h/52d Inode: 844424930132069  Links: 1     Device type: 0,0
Access: (0755/crwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:46:51.839458900 -0500
Modify: 2020-10-21 17:46:51.839458900 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/fifo
  Size: 0          Blocks: 0          IO Block: 16384  fifo
Device: 34h/52d Inode: 1125899906842722  Links: 1
Access: (0755/prwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 16:21:37.259249700 -0500
Modify: 2020-10-21 16:21:37.259249700 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/block
  Size: 0          Blocks: 0          IO Block: 16384  block special file
Device: 34h/52d Inode: 844424930132068  Links: 1     Device type: 0,0
Access: (0755/brwxr-xr-x)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:10:47.913103200 -0500
Modify: 2020-10-21 17:10:47.913103200 -0500
Change: 2020-10-21 18:30:39.796725500 -0500
 Birth: -

without the patch all show up incorrectly as symlinks with annoying "operation not supported error also returned"
  File: /mnt1/charstat: cannot read symbolic link '/mnt1/char': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 844424930132069  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:46:51.839458900 -0500
Modify: 2020-10-21 17:46:51.839458900 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/fifostat: cannot read symbolic link '/mnt1/fifo': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 1125899906842722  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 16:21:37.259249700 -0500
Modify: 2020-10-21 16:21:37.259249700 -0500
Change: 2020-10-21 18:30:39.797358800 -0500
 Birth: -
  File: /mnt1/blockstat: cannot read symbolic link '/mnt1/block': Operation not supported

  Size: 0          Blocks: 0          IO Block: 16384  symbolic link
Device: 34h/52d Inode: 844424930132068  Links: 1
Access: (0000/l---------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2020-10-21 17:10:47.913103200 -0500
Modify: 2020-10-21 17:10:47.913103200 -0500
Change: 2020-10-21 18:30:39.796725500 -0500
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>

The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
are preferred by the Linux client in some cases since, unlike
the NFS reparse tag (or EAs), they don't require an extra query
to determine which type of special file they represent.

Add support for readdir to recognize special file types of
FIFO, SOCKET, CHAR, BLOCK and SYMLINK.  This can be tested
by creating these special files in WSL Linux and then
sharing that location on the Windows server and mounting
to the Windows server to access them.

Prior to this patch all of the special files would show up
as being of type 'file' but with this patch they can be seen
with the correct file type as can be seen below:

  brwxr-xr-x 1 root root 0, 0 Oct 21 17:10 block
  crwxr-xr-x 1 root root 0, 0 Oct 21 17:46 char
  drwxr-xr-x 2 root root    0 Oct 21 18:27 dir
  prwxr-xr-x 1 root root    0 Oct 21 16:21 fifo
  -rwxr-xr-x 1 root root    0 Oct 21 15:48 file
  lrwxr-xr-x 1 root root    0 Oct 21 15:52 symlink-to-file

TODO: go through all documented reparse tags to see if we can
reasonably map some of them to directories vs. files vs. symlinks
and also add support for device numbers for block and char
devices.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>

The "end" pointer is either NULL or it points to the next byte to parse.
If there isn't a next byte then dereferencing "end" is an off-by-one out
of bounds error.  And, of course, if it's NULL that leads to an Oops.
Printing "*end" doesn't seem very useful so let's delete this code.

Also for the last debug statement, I noticed that it should be printing
"sequence_end" instead of "end" so fix that as well.
Reported-by: NDominik Maier <dmaier@sect.tu-berlin.de>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Fix minor typo in new compression flag define
Reported-by: NTom Talpey <tom@talpey.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

This and related patches which move mount related
code to fs_context.c has the advantage of
shriking the code in fs/cifs/connect.c (which had
the second most lines of code of any of the files
in cifs.ko and was getting harder to read due
to its size) and will also make it easier to
switch over to the new mount API in the future.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Helps to shrink connect.c and make it more readable
by moving mount related code to fs_context.c and
fs_context.h
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>

This patch moves the parsing of security mount options into
fs_context.ch.  There are no changes to any logic.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>

This will make it easier in the future, but also will allow us to
shrink connect.c which is getting too big, and harder to read
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>

To servers which do not support directory leases (e.g. Samba)
it is wasteful to try to open_shroot (ie attempt to cache the
root directory handle).  Skip attempt to open_shroot when
server does not indicate support for directory leases.

Cuts the number of requests on mount from 17 to 15, and
cuts the number of requests on stat of the root directory
from 4 to 3.
Signed-off-by: NSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org> # v5.1+

When mounting with modefromsid mount option, it was possible to
get the error on stat of a fifo or char or block device:
        "cannot stat <filename>: Operation not supported"

Special devices can be stored as reparse points by some servers
(e.g. Windows NFS server and when using the SMB3.1.1 POSIX
Extensions) but when the modefromsid mount option is used
the client attempts to get the ACL for the file which requires
opening with OPEN_REPARSE_POINT create option.
Signed-off-by: NSteve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NShyam Prasad N <sprasad@microsoft.com>

Can be helpful in debugging mount and reconnect issues
Signed-off-by: NSamuel Cabrero <scabrero@suse.de>
Reviewed-by: NShyam Prasad N <sprasad@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

TCP server info field server->total_read is modified in parallel by
demultiplex thread and decrypt offload worker thread. server->total_read
is used in calculation to discard the remaining data of PDU which is
not read into memory.

Because of parallel modification, server->total_read can get corrupted
and can result in discarding the valid data of next PDU.
Signed-off-by: NRohith Surabattula <rohiths@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org> #5.4+
Signed-off-by: NSteve French <stfrench@microsoft.com>

Don't populate const array smb3_create_tag_posix on the stack but
instead make it static. Makes the object code smaller by 50 bytes.

Before:
   text	   data	    bss	    dec	    hex	filename
 150184	  47167	      0	 197351	  302e7	fs/cifs/smb2pdu.o

After:
    text	   data	    bss	    dec	    hex	filename
 150070	  47231	      0	 197301	  302b5	fs/cifs/smb2pdu.o

(gcc version 10.2.0)
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

We were setting the uid/gid to the default in each dir entry
in the parsing of the POSIX query dir response, rather
than attempting to map the user and group SIDs returned by
the server to well known SIDs (or upcall if not found).

CC: Stable <stable@vger.kernel.org>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

SMB3 crediting is used for flow control, and it can be useful to
trace for problem determination how many credits were acquired
and for which operation.

Here is an example ("trace-cmd record -e *add_credits"):
cifsd-9522    [010] ....  5995.202712: smb3_add_credits:
	server=localhost current_mid=0x12 credits=373 credits_to_add=10
cifsd-9522    [010] ....  5995.204040: smb3_add_credits:
	server=localhost current_mid=0x15 credits=400 credits_to_add=30
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

There are cases where the server can return a cipher type of 0 and
it not be an error. For example server supported no encryption types
(e.g. server completely disabled encryption), or the server and
client didn't support any encryption types in common (e.g. if a
server only supported AES256_CCM). In those cases encryption would
not be supported, but that can be ok if the client did not require
encryption on mount and it should not return an error.

In the case in which mount requested encryption ("seal" on mount)
then checks later on during tree connection will return the proper
rc, but if seal was not requested by client, since server is allowed
to return 0 to indicate no supported cipher, we should not fail mount.
Reported-by: NPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

In crypt_message, when smb2_get_enc_key returns error, we need to
return the error back to the caller. If not, we end up processing
the message further, causing a kernel oops due to unwarranted access
of memory.

Call Trace:
smb3_receive_transform+0x120/0x870 [cifs]
cifs_demultiplex_thread+0xb53/0xc20 [cifs]
? cifs_handle_standard+0x190/0x190 [cifs]
kthread+0x116/0x130
? kthread_park+0x80/0x80
ret_from_fork+0x1f/0x30
Signed-off-by: NShyam Prasad N <sprasad@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NSteve French <stfrench@microsoft.com>

update smb encryption code to set 32 byte key length and to
set gcm256 when requested on mount.
Signed-off-by: NSteve French <stfrench@microsoft.com>

Now that 256 bit encryption can be negotiated, update
names of the nonces to match the updated official protocol
documentation (e.g. AES_GCM_NONCE instead of AES_128GCM_NONCE)
since they apply to both 128 bit and 256 bit encryption.
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

If server does not support AES-256-GCM and it was required on mount, print
warning message. Also log and return a different error message (EOPNOTSUPP)
when encryption mechanism is not supported vs the case when an unknown
unrequested encryption mechanism could be returned (EINVAL).
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

Add new module load parameter enable_gcm_256. If set, then add
AES-256-GCM (strongest encryption type) to the list of encryption
types requested. Put it in the list as the second choice (since
AES-128-GCM is faster and much more broadly supported by
SMB3 servers).  To make this stronger encryption type, GCM-256,
required (the first and only choice, you would use module parameter
"require_gcm_256."
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Add new module load parameter require_gcm_256. If set, then only
request AES-256-GCM (strongest encryption type).
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

This is basically the same as STATUS_LOGON_FAILURE,
but after the account is locked out.
Signed-off-by: NStefan Metzmacher <metze@samba.org>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Currently there are three supported signing algorithms
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

RHBZ: 1848178

Some calls that set attributes, like utimensat(), are not supposed to return
-EINTR and thus do not have handlers for this in glibc which causes us
to leak -EINTR to the applications which are also unprepared to handle it.

For example tar will break if utimensat() return -EINTR and abort unpacking
the archive. Other applications may break too.

To handle this we add checks, and retry, for -EINTR in cifs_setattr()
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Currently STATUS_IO_TIMEOUT is not treated as retriable error.
It is currently mapped to ETIMEDOUT and returned to userspace
for most system calls. STATUS_IO_TIMEOUT is returned by server
in case of unavailability or throttling errors.

This patch will map the STATUS_IO_TIMEOUT to EAGAIN, so that it
can be retried. Also, added a check to drop the connection to
not overload the server in case of ongoing unavailability.
Signed-off-by: NRohith Surabattula <rohiths@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Cleanup patch for followon to cache additional information for the root directory
when directory lease held.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Cleanup patch for followon to cache additional information for the root directory
when directory lease held.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

MS-SMB2 was updated recently to include new protocol definitions for
updated compression payload header and new RDMA transform capabilities
Update structure definitions in smb2pdu.h to match
Signed-off-by: NSteve French <stfrench@microsoft.com>
Acked-by: NRonnie Sahlberg <lsahlber@redhat.com>

In encryption capabilities negotiate context can now request
AES256 GCM or CCM
Signed-off-by: NSteve French <stfrench@microsoft.com>
Acked-by: NRonnie Sahlberg <lsahlber@redhat.com>

When converting trailing spaces and periods in paths, do so
for every component of the path, not just the last component.
If the conversion is not done for every path component, then
subsequent operations in directories with trailing spaces or
periods (e.g. create(), mkdir()) will fail with ENOENT. This
is because on the server, the directory will have a special
symbol in its name, and the client needs to provide the same.
Signed-off-by: NBoris Protopopov <pboris@amazon.com>
Acked-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

On setxattr() syscall path due to an apprent typo the size of a dynamically
allocated memory chunk for storing struct smb2_file_full_ea_info object is
computed incorrectly, to be more precise the first addend is the size of
a pointer instead of the wanted object size. Coincidentally it makes no
difference on 64-bit platforms, however on 32-bit targets the following
memcpy() writes 4 bytes of data outside of the dynamically allocated memory.

  =============================================================================
  BUG kmalloc-16 (Not tainted): Redzone overwritten
  -----------------------------------------------------------------------------

  Disabling lock debugging due to kernel taint
  INFO: 0x79e69a6f-0x9e5cdecf @offset=368. First byte 0x73 instead of 0xcc
  INFO: Slab 0xd36d2454 objects=85 used=51 fp=0xf7d0fc7a flags=0x35000201
  INFO: Object 0x6f171df3 @offset=352 fp=0x00000000

  Redzone 5d4ff02d: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc  ................
  Object 6f171df3: 00 00 00 00 00 05 06 00 73 6e 72 75 62 00 66 69  ........snrub.fi
  Redzone 79e69a6f: 73 68 32 0a                                      sh2.
  Padding 56254d82: 5a 5a 5a 5a 5a 5a 5a 5a                          ZZZZZZZZ
  CPU: 0 PID: 8196 Comm: attr Tainted: G    B             5.9.0-rc8+ #3
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014
  Call Trace:
   dump_stack+0x54/0x6e
   print_trailer+0x12c/0x134
   check_bytes_and_report.cold+0x3e/0x69
   check_object+0x18c/0x250
   free_debug_processing+0xfe/0x230
   __slab_free+0x1c0/0x300
   kfree+0x1d3/0x220
   smb2_set_ea+0x27d/0x540
   cifs_xattr_set+0x57f/0x620
   __vfs_setxattr+0x4e/0x60
   __vfs_setxattr_noperm+0x4e/0x100
   __vfs_setxattr_locked+0xae/0xd0
   vfs_setxattr+0x4e/0xe0
   setxattr+0x12c/0x1a0
   path_setxattr+0xa4/0xc0
   __ia32_sys_lsetxattr+0x1d/0x20
   __do_fast_syscall_32+0x40/0x70
   do_fast_syscall_32+0x29/0x60
   do_SYSENTER_32+0x15/0x20
   entry_SYSENTER_32+0x9f/0xf2

Fixes: 5517554e ("cifs: Add support for writing attributes on SMB2+")
Signed-off-by: NVladimir Zapolskiy <vladimir@tuxera.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

RHBZ: 1871246

If during cifs_lookup()/get_inode_info() we encounter a DFS link
and we use the cifsacl or modefromsid mount options we must suppress
any -EREMOTE errors that triggers or else we will not be able to follow
the DFS link and automount the target.

This fixes an issue with modefromsid/cifsacl where these mountoptions
would break DFS and we would no longer be able to access the share.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NPaulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: NSteve French <stfrench@microsoft.com>

For SMB1, the DFS flag should be checked against tcon->Flags rather
than tcon->share_flags.  While at it, add an is_tcon_dfs() helper to
check for DFS capability in a more generic way.
Signed-off-by: NPaulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NShyam Prasad N <nspmangalore@gmail.com>