Now we just return NULL cifsFileInfo pointer in cases we didn't find
or couldn't reopen a file. This hides errors from cifs_reopen_file()
especially retryable errors which should be handled appropriately.
Create new cifs_get_writable_file() routine that returns error codes
from cifs_reopen_file() and use it in the writeback codepath.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

The reconnect might have happended after we obtained credits
and before we acquired srv_mutex. Check for that under the mutex
and retry an async operation if the reconnect is detected.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Every time after a session reconnect we don't need to account for
credits obtained in previous sessions. Introduce new struct cifs_credits
which contains both credits value and reconnect instance of the
time those credits were taken. Modify a routine that add credits
back to handle the reconnect instance by assuming zero credits
if the reconnect happened after the credits were obtained and
before we decided to add them back due to some errors during sending.

This patch fixes the MTU credits cases. The subsequent patch
will handle non-MTU ones.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

After a successful failover in cifs_reconnect(), the smb2_reconnect()
function will make sure to reconnect every tcon to new target server.

For SMB2+.
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

This patch will make use of DFS cache routines where appropriate and
do not always request a new referral from server.
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

* Add new dfs_cache.[ch] files

* Add new /proc/fs/cifs/dfscache file
  - dump current cache when read
  - clear current cache when writing "0" to it

* Add delayed_work to periodically refresh cache entries

The new interface will be used for caching DFS referrals, as well as
supporting client target failover.

The DFS cache is a hashtable that maps UNC paths to cache entries.

A cache entry contains:
- the UNC path it is mapped on
- how much the the UNC path the entry consumes
- flags
- a Time-To-Live after which the entry expires
- a list of possible targets (linked lists of UNC paths)
- a "hint target" pointing the last known working target or the first
  target if none were tried. This hint lets cifs.ko remember and try
  working targets first.

* Looking for an entry in the cache is done with dfs_cache_find()
  - if no valid entries are found, a DFS query is made, stored in the
    cache and returned
  - the full target list can be copied and returned to avoid race
    conditions and looped on with the help with the
    dfs_cache_tgt_iterator

* Updating the target hint to the next target is done with
  dfs_cache_update_tgthint()

These functions have a dfs_cache_noreq_XXX() version that doesn't
fetches referrals if no entries are found. These versions don't
require the tcp/ses/tcon/cifs_sb parameters as a result.

Expired entries cannot be used and since they have a pretty short TTL
[1] in order for them to be useful for failover the DFS cache adds a
delayed work called periodically to keep them fresh.

Since we might not have available connections to issue the referral
request when refreshing we need to store volume_info structs with
credentials and other needed info to be able to connect to the right
server.

1: Windows defaults: 5mn for domain-based referrals, 30mn for regular
links
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

* Split and refactor the very large function cifs_mount() in multiple
  functions:

- tcp, ses and tcon setup to mount_get_conns()
- tcp, ses and tcon cleanup in mount_put_conns()
- tcon tlink setup to mount_setup_tlink()
- remote path checking to is_path_remote()

* Implement 2 version of cifs_mount() for DFS-enabled builds and
  non-DFS-enabled builds (CONFIG_CIFS_DFS_UPCALL).

In preparation for DFS failover support.
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

RHBZ 1484130

Update cifs_find_fid_lock_conflict() to recognize that
ODF locks do not conflict with eachother.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

In cifs, the timestamps are stored in memory in the cifs_fattr structure,
which uses the deprecated 'timespec' structure. Now that the VFS code
has moved on to 'timespec64', the next step is to change over the fattr
as well.

This also makes 32-bit and 64-bit systems behave the same way, and
no longer overflow the 32-bit time_t in year 2038.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NPaulo Alcantara <palcantara@suse.de>
Signed-off-by: NSteve French <stfrench@microsoft.com>

With protocol version 2.0 mounts we have seen crashes with corrupt mid
entries. Either the server->pending_mid_q list becomes corrupt with a
cyclic reference in one element or a mid object fetched by the
demultiplexer thread becomes overwritten during use.

Code review identified a race between the demultiplexer thread and the
request issuing thread. The demultiplexer thread seems to be written
with the assumption that it is the sole user of the mid object until
it calls the mid callback which either wakes the issuer task or
deletes the mid.

This assumption is not true because the issuer task can be woken up
earlier by a signal. If the demultiplexer thread has proceeded as far
as setting the mid_state to MID_RESPONSE_RECEIVED then the issuer
thread will happily end up calling cifs_delete_mid while the
demultiplexer thread still is using the mid object.

Inserting a delay in the cifs demultiplexer thread widens the race
window and makes reproduction of the race very easy:

		if (server->large_buf)
			buf = server->bigbuf;

+		usleep_range(500, 4000);

		server->lstrp = jiffies;

To resolve this I think the proper solution involves putting a
reference count on the mid object. This patch makes sure that the
demultiplexer thread holds a reference until it has finished
processing the transaction.

Cc: stable@vger.kernel.org
Signed-off-by: NLars Persson <larper@axis.com>
Acked-by: NPaulo Alcantara <palcantara@suse.de>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Now that we have the plumbing to pass request without an rfc1002
header all the way down to the point we write to the socket we no
longer need the smb2_send_recv() function.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Move the generation of the 4 byte length field down the stack and
generate it immediately before we start writing the data to the socket.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Use a read lease for the cached root fid so that we can detect
when the content of the directory changes (via a break) at which time
we close the handle. On next access to the root the handle will be reopened
and cached again.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

if mounting as smb3 do not allow cifs (vers=1.0) or insecure vers=2.0
mounts.

For example:
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1
root@smf-Thinkpad-P51:~/cifs-2.6# umount /mnt
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1,vers=1.0
mount: /mnt: wrong fs type, bad option, bad superblock on //127.0.0.1/scratch ...
root@smf-Thinkpad-P51:~/cifs-2.6# dmesg | grep smb3
[ 4302.200122] CIFS VFS: vers=1.0 (cifs) not permitted when mounting with smb3
root@smf-Thinkpad-P51:~/cifs-2.6# mount -t smb3 //127.0.0.1/scratch /mnt -o username=testuser,password=Testpass1,vers=3.11
Signed-off-by: NSteve French <stfrench@microsoft.com>
Acked-by: NPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Reviewed-by: NSachin Prabhu <sprabhu@redhat.com>

Introduce a function rqst_page_get_length to return the page offset and
length for a given page in smb_rqst. This function is to be used by
following patches.
Signed-off-by: NLong Li <longli@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

It seems Ronnie's preamble removal broke signing.

the signing functions are called when:

A) we send a request (to sign it)
B) when we recv a response (to check the signature).

On code path A, the smb2 header is in iov[1] but on code path B, the
smb2 header is in iov[0] (and there's only one vector).

So we have different iov indexes for the smb2 header but the signing
function always use index 1. Fix this by checking the nb of io vectors
in the signing function as a hint.
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Add a function to allocate wdata without allocating pages for data
transfer. This gives the caller an option to pass a number of pages that
point to the data buffer to write to.

wdata is reponsible for free those pages after it's done.
Signed-off-by: NLong Li <longli@microsoft.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

With offset defined in rdata, transport functions need to look at this
offset when reading data into the correct places in pages.
Signed-off-by: NLong Li <longli@microsoft.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Signed-off-by: NSteve French <smfrench@gmail.com>

and change the smb2 version to take heder_preamble_size into account
instead of hardcoding it as 4 bytes.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

shash and sdesc and always allocated and freed together.
* abstract this in new functions cifs_alloc_hash() and cifs_free_hash().
* make smb2/3 crypto allocation independent from each other.
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>

This function is similar to SendReceive2 except it does not expect
a 4 byte rfc1002 length header in the first io vector.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

This adds support for writing extended attributes on SMB2+ shares.
Attributes can be written using the setfattr command.

RH-bz: 1110709
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

Some minor cleanup of cifs query xattr functions (will also make
SMB3 xattr implementation cleaner as well).
Signed-off-by: NSteve French <steve.french@primarydata.com>

Currently the code doesn't recognize asynchronous calls passed
by io_submit() and processes all calls synchronously. This is not
what kernel AIO expects. This patch introduces a new async context
that keeps track of all issued i/o requests and moves a response
collecting procedure to a separate thread. This allows to return
to a caller immediately for async calls and call iocb->ki_complete()
once all requests are completed. For sync calls the current thread
simply waits until all requests are completed.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Currently during receiving a read response mid->resp_buf can be
NULL when it is being passed to cifs_discard_remaining_data() from
cifs_readv_discard(). Fix it by always passing server->smallbuf
instead and initializing mid->resp_buf at the end of read response
processing.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Acked-by: NSachin Prabhu <sprabhu@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

A signal can interrupt a SendReceive call which result in incoming
responses to the call being ignored. This is a problem for calls such as
open which results in the successful response being ignored. This
results in an open file resource on the server.

The patch looks into responses which were cancelled after being sent and
in case of successful open closes the open fids.

For this patch, the check is only done in SendReceive2()

RH-bz: 1403319
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Cc: Stable <stable@vger.kernel.org>

If the security type specified using a mount option is not supported,
the SMB2 session setup code changes the security type to RawNTLMSSP. We
should instead fail the mount and return an error.

The patch changes the code for SMB2 to make it similar to the code used
for SMB1. Like in SMB1, we now use the global security flags to select
the security method to be used when no security method is specified and
to return an error when the requested auth method is not available.

For SMB2, we also use ntlmv2 as a synonym for nltmssp.
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Acked-by: NPavel Shilovsky <pshilov@microsoft.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

this function does the same thing as add build_path_from_dentry() but
takes a boolean parameter to decide whether or not to prefix the path
with the tree name.

we cannot rely on tcon->Flags & SMB_SHARE_IS_IN_DFS for SMB2 as smb2
code never sets tcon->Flags but it sets tcon->share_flags and it seems
the SMB_SHARE_IS_IN_DFS has different semantics in SMB2: the prefix
shouldn't be added everytime it was in SMB1.
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Acked-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

since the DFS payload is not tied to the SMB version we can:
* isolate the DFS payload in its own struct, and include that struct in
  packet structs
* move the function that parses the response to misc.c and make it work
  on the new DFS payload struct (add payload size and utf16 flag as a
  result).
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Acked-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

Allow to decrypt transformed packets that are bigger than the big
buffer size. In particular it is used for read responses that can
only exceed the big buffer size.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

Allow to decrypt transformed packets, find a corresponding mid
and process as usual further.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

We need to process read responses differently because the data
should go directly into preallocated pages. This can be done
by specifying a mid handle callback.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

This change allows to encrypt packets if it is required by a server
for SMB sessions or tree connections.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

Allocate and initialize SMB2 read request without RFC1001 length
field to directly call cifs_send_recv() rather than SendReceive2()
in a read codepath.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

Now SendReceive2 frees the first iov and returns a response buffer
in it that increases a code complexity. Simplify this by making
a caller responsible for freeing request buffer itself and returning
a response buffer in a separate iov.
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

When a server returns the optional flag SMB_SHARE_IS_IN_DFS in response
to a tree connect, cifs_build_path_to_root() will return a pathname
which includes the hostname. This causes problems with cifs_get_root()
which separates each component and does a lookup for each component of
the path which in this case will incorrectly include looking up the
hostname component as a path component.

We encountered a problem with dfs shares hosted by a Netapp. When
connecting to nodes pointed to by the DFS share. The tree connect for
these nodes return SMB_SHARE_IS_IN_DFS resulting failures in lookup
in cifs_get_root().

RH bz: 1373153
The patch was tested against a Netapp simulator and by a user using an
actual Netapp server.
Signed-off-by: NSachin Prabhu <sprabhu@redhat.com>
Reported-by: NPierguido Lambri <plambri@redhat.com>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <smfrench@gmail.com>

We can not unlock/lock cifs_tcp_ses_lock while walking through ses
and tcon lists because it can corrupt list iterator pointers and
a tcon structure can be released if we don't hold an extra reference.
Fix it by moving a reconnect process to a separate delayed work
and acquiring a reference to every tcon that needs to be reconnected.
Also do not send an echo request on newly established connections.

CC: Stable <stable@vger.kernel.org>
Signed-off-by: NPavel Shilovsky <pshilov@microsoft.com>

Continuous Availability features like persistent handles
require that clients reconnect their open files, not
just the sessions, soon after the network connection comes
back up, otherwise the server will throw away the state
(byte range locks, leases, deny modes) on those handles
after a timeout.

Add code to reconnect handles when use_persistent set
(e.g. Continuous Availability shares) after tree reconnect.
Signed-off-by: NAurelien Aptel <aaptel@suse.com>
Reviewed-by: NGermano Percossi <germano.percossi@citrix.com>
Signed-off-by: NSteve French <smfrench@gmail.com>