smb2pdu.c

Go to the documentation of this file.

/*
 *   fs/cifs/smb2pdu.c
 *
 *   Copyright (C) International Business Machines  Corp., 2009, 2012
 *                 Etersoft, 2012
 *   Author(s): Steve French ([email protected])
 *              Pavel Shilovsky ([email protected]) 2012
 *
 *   Contains the routines for constructing the SMB2 PDUs themselves
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

 /* SMB2 PDU handling routines here - except for leftovers (eg session setup) */
 /* Note that there are handle based routines which must be           */
 /* treated slightly differently for reconnection purposes since we never     */
 /* want to reuse a stale file handle and only the caller knows the file info */

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/vfs.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/uaccess.h>
#include <linux/pagemap.h>
#include <linux/xattr.h>
#include "smb2pdu.h"
#include "cifsglob.h"
#include "cifsacl.h"
#include "cifsproto.h"
#include "smb2proto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "ntlmssp.h"
#include "smb2status.h"
#include "smb2glob.h"
#include "cifspdu.h"

/*
 *  The following table defines the expected "StructureSize" of SMB2 requests
 *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS requests.
 *
 *  Note that commands are defined in smb2pdu.h in le16 but the array below is
 *  indexed by command in host byte order.
 */
static const int smb2_req_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
    /* SMB2_NEGOTIATE */ 36,
    /* SMB2_SESSION_SETUP */ 25,
    /* SMB2_LOGOFF */ 4,
    /* SMB2_TREE_CONNECT */ 9,
    /* SMB2_TREE_DISCONNECT */ 4,
    /* SMB2_CREATE */ 57,
    /* SMB2_CLOSE */ 24,
    /* SMB2_FLUSH */ 24,
    /* SMB2_READ */ 49,
    /* SMB2_WRITE */ 49,
    /* SMB2_LOCK */ 48,
    /* SMB2_IOCTL */ 57,
    /* SMB2_CANCEL */ 4,
    /* SMB2_ECHO */ 4,
    /* SMB2_QUERY_DIRECTORY */ 33,
    /* SMB2_CHANGE_NOTIFY */ 32,
    /* SMB2_QUERY_INFO */ 41,
    /* SMB2_SET_INFO */ 33,
    /* SMB2_OPLOCK_BREAK */ 24 /* BB this is 36 for LEASE_BREAK variant */
};


static void
smb2_hdr_assemble(struct smb2_hdr *hdr, __le16 smb2_cmd /* command */ ,
          const struct cifs_tcon *tcon)
{
    struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
    char *temp = (char *)hdr;
    /* lookup word count ie StructureSize from table */
    __u16 parmsize = smb2_req_struct_sizes[le16_to_cpu(smb2_cmd)];

    /*
     * smaller than SMALL_BUFFER_SIZE but bigger than fixed area of
     * largest operations (Create)
     */
    memset(temp, 0, 256);

    /* Note this is only network field converted to big endian */
    hdr->smb2_buf_length = cpu_to_be32(parmsize + sizeof(struct smb2_hdr)
            - 4 /*  RFC 1001 length field itself not counted */);

    hdr->ProtocolId[0] = 0xFE;
    hdr->ProtocolId[1] = 'S';
    hdr->ProtocolId[2] = 'M';
    hdr->ProtocolId[3] = 'B';
    hdr->StructureSize = cpu_to_le16(64);
    hdr->Command = smb2_cmd;
    hdr->CreditRequest = cpu_to_le16(2); /* BB make this dynamic */
    hdr->ProcessId = cpu_to_le32((__u16)current->tgid);

    if (!tcon)
        goto out;

    hdr->TreeId = tcon->tid;
    /* Uid is not converted */
    if (tcon->ses)
        hdr->SessionId = tcon->ses->Suid;
    /* BB check following DFS flags BB */
    /* BB do we have to add check for SHI1005_FLAGS_DFS_ROOT too? */
    if (tcon->share_flags & SHI1005_FLAGS_DFS)
        hdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS;
    /* BB how does SMB2 do case sensitive? */
    /* if (tcon->nocase)
        hdr->Flags |= SMBFLG_CASELESS; */
    if (tcon->ses && tcon->ses->server &&
        (tcon->ses->server->sec_mode & SECMODE_SIGN_REQUIRED))
        hdr->Flags |= SMB2_FLAGS_SIGNED;
out:
    pdu->StructureSize2 = cpu_to_le16(parmsize);
    return;
}

static int
smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
{
    int rc = 0;
    struct nls_table *nls_codepage;
    struct cifs_ses *ses;
    struct TCP_Server_Info *server;

    /*
     * SMB2s NegProt, SessSetup, Logoff do not have tcon yet so
     * check for tcp and smb session status done differently
     * for those three - in the calling routine.
     */
    if (tcon == NULL)
        return rc;

    if (smb2_command == SMB2_TREE_CONNECT)
        return rc;

    if (tcon->tidStatus == CifsExiting) {
        /*
         * only tree disconnect, open, and write,
         * (and ulogoff which does not have tcon)
         * are allowed as we start force umount.
         */
        if ((smb2_command != SMB2_WRITE) &&
           (smb2_command != SMB2_CREATE) &&
           (smb2_command != SMB2_TREE_DISCONNECT)) {
            cFYI(1, "can not send cmd %d while umounting",
                smb2_command);
            return -ENODEV;
        }
    }
    if ((!tcon->ses) || (tcon->ses->status == CifsExiting) ||
        (!tcon->ses->server))
        return -EIO;

    ses = tcon->ses;
    server = ses->server;

    /*
     * Give demultiplex thread up to 10 seconds to reconnect, should be
     * greater than cifs socket timeout which is 7 seconds
     */
    while (server->tcpStatus == CifsNeedReconnect) {
        /*
         * Return to caller for TREE_DISCONNECT and LOGOFF and CLOSE
         * here since they are implicitly done when session drops.
         */
        switch (smb2_command) {
        /*
         * BB Should we keep oplock break and add flush to exceptions?
         */
        case SMB2_TREE_DISCONNECT:
        case SMB2_CANCEL:
        case SMB2_CLOSE:
        case SMB2_OPLOCK_BREAK:
            return -EAGAIN;
        }

        wait_event_interruptible_timeout(server->response_q,
            (server->tcpStatus != CifsNeedReconnect), 10 * HZ);

        /* are we still trying to reconnect? */
        if (server->tcpStatus != CifsNeedReconnect)
            break;

        /*
         * on "soft" mounts we wait once. Hard mounts keep
         * retrying until process is killed or server comes
         * back on-line
         */
        if (!tcon->retry) {
            cFYI(1, "gave up waiting on reconnect in smb_init");
            return -EHOSTDOWN;
        }
    }

    if (!tcon->ses->need_reconnect && !tcon->need_reconnect)
        return rc;

    nls_codepage = load_nls_default();

    /*
     * need to prevent multiple threads trying to simultaneously reconnect
     * the same SMB session
     */
    mutex_lock(&tcon->ses->session_mutex);
    rc = cifs_negotiate_protocol(0, tcon->ses);
    if (!rc && tcon->ses->need_reconnect)
        rc = cifs_setup_session(0, tcon->ses, nls_codepage);

    if (rc || !tcon->need_reconnect) {
        mutex_unlock(&tcon->ses->session_mutex);
        goto out;
    }

    cifs_mark_open_files_invalid(tcon);
    rc = SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nls_codepage);
    mutex_unlock(&tcon->ses->session_mutex);
    cFYI(1, "reconnect tcon rc = %d", rc);
    if (rc)
        goto out;
    atomic_inc(&tconInfoReconnectCount);
    /*
     * BB FIXME add code to check if wsize needs update due to negotiated
     * smb buffer size shrinking.
     */
out:
    /*
     * Check if handle based operation so we know whether we can continue
     * or not without returning to caller to reset file handle.
     */
    /*
     * BB Is flush done by server on drop of tcp session? Should we special
     * case it and skip above?
     */
    switch (smb2_command) {
    case SMB2_FLUSH:
    case SMB2_READ:
    case SMB2_WRITE:
    case SMB2_LOCK:
    case SMB2_IOCTL:
    case SMB2_QUERY_DIRECTORY:
    case SMB2_CHANGE_NOTIFY:
    case SMB2_QUERY_INFO:
    case SMB2_SET_INFO:
        return -EAGAIN;
    }
    unload_nls(nls_codepage);
    return rc;
}

/*
 * Allocate and return pointer to an SMB request hdr, and set basic
 * SMB information in the SMB header. If the return code is zero, this
 * function must have filled in request_buf pointer.
 */
static int
small_smb2_init(__le16 smb2_command, struct cifs_tcon *tcon,
        void **request_buf)
{
    int rc = 0;

    rc = smb2_reconnect(smb2_command, tcon);
    if (rc)
        return rc;

    /* BB eventually switch this to SMB2 specific small buf size */
    *request_buf = cifs_small_buf_get();
    if (*request_buf == NULL) {
        /* BB should we add a retry in here if not a writepage? */
        return -ENOMEM;
    }

    smb2_hdr_assemble((struct smb2_hdr *) *request_buf, smb2_command, tcon);

    if (tcon != NULL) {
#ifdef CONFIG_CIFS_STATS2
        uint16_t com_code = le16_to_cpu(smb2_command);
        cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_sent[com_code]);
#endif
        cifs_stats_inc(&tcon->num_smbs_sent);
    }

    return rc;
}

static void
free_rsp_buf(int resp_buftype, void *rsp)
{
    if (resp_buftype == CIFS_SMALL_BUFFER)
        cifs_small_buf_release(rsp);
    else if (resp_buftype == CIFS_LARGE_BUFFER)
        cifs_buf_release(rsp);
}


/*
 *
 *  SMB2 Worker functions follow:
 *
 *  The general structure of the worker functions is:
 *  1) Call smb2_init (assembles SMB2 header)
 *  2) Initialize SMB2 command specific fields in fixed length area of SMB
 *  3) Call smb_sendrcv2 (sends request on socket and waits for response)
 *  4) Decode SMB2 command specific fields in the fixed length area
 *  5) Decode variable length data area (if any for this SMB2 command type)
 *  6) Call free smb buffer
 *  7) return
 *
 */

int
SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
{
    struct smb2_negotiate_req *req;
    struct smb2_negotiate_rsp *rsp;
    struct kvec iov[1];
    int rc = 0;
    int resp_buftype;
    struct TCP_Server_Info *server;
    unsigned int sec_flags;
    u16 temp = 0;
    int blob_offset, blob_length;
    char *security_blob;
    int flags = CIFS_NEG_OP;

    cFYI(1, "Negotiate protocol");

    if (ses->server)
        server = ses->server;
    else {
        rc = -EIO;
        return rc;
    }

    rc = small_smb2_init(SMB2_NEGOTIATE, NULL, (void **) &req);
    if (rc)
        return rc;

    /* if any of auth flags (ie not sign or seal) are overriden use them */
    if (ses->overrideSecFlg & (~(CIFSSEC_MUST_SIGN | CIFSSEC_MUST_SEAL)))
        sec_flags = ses->overrideSecFlg;  /* BB FIXME fix sign flags?*/
    else /* if override flags set only sign/seal OR them with global auth */
        sec_flags = global_secflags | ses->overrideSecFlg;

    cFYI(1, "sec_flags 0x%x", sec_flags);

    req->hdr.SessionId = 0;

    req->Dialects[0] = cpu_to_le16(ses->server->vals->protocol_id);

    req->DialectCount = cpu_to_le16(1); /* One vers= at a time for now */
    inc_rfc1001_len(req, 2);

    /* only one of SMB2 signing flags may be set in SMB2 request */
    if ((sec_flags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN)
        temp = SMB2_NEGOTIATE_SIGNING_REQUIRED;
    else if (sec_flags & CIFSSEC_MAY_SIGN) /* MAY_SIGN is a single flag */
        temp = SMB2_NEGOTIATE_SIGNING_ENABLED;

    req->SecurityMode = cpu_to_le16(temp);

    req->Capabilities = cpu_to_le32(ses->server->vals->req_capabilities);

    memcpy(req->ClientGUID, cifs_client_guid, SMB2_CLIENT_GUID_SIZE);

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov[0].iov_len = get_rfc1002_length(req) + 4;

    rc = SendReceive2(xid, ses, iov, 1, &resp_buftype, flags);

    rsp = (struct smb2_negotiate_rsp *)iov[0].iov_base;
    /*
     * No tcon so can't do
     * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
     */
    if (rc != 0)
        goto neg_exit;

    cFYI(1, "mode 0x%x", rsp->SecurityMode);

    /* BB we may eventually want to match the negotiated vs. requested
       dialect, even though we are only requesting one at a time */
    if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID))
        cFYI(1, "negotiated smb2.0 dialect");
    else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID))
        cFYI(1, "negotiated smb2.1 dialect");
    else if (rsp->DialectRevision == cpu_to_le16(SMB30_PROT_ID))
        cFYI(1, "negotiated smb3.0 dialect");
    else {
        cERROR(1, "Illegal dialect returned by server %d",
               le16_to_cpu(rsp->DialectRevision));
        rc = -EIO;
        goto neg_exit;
    }
    server->dialect = le16_to_cpu(rsp->DialectRevision);

    server->maxBuf = le32_to_cpu(rsp->MaxTransactSize);
    server->max_read = le32_to_cpu(rsp->MaxReadSize);
    server->max_write = le32_to_cpu(rsp->MaxWriteSize);
    /* BB Do we need to validate the SecurityMode? */
    server->sec_mode = le16_to_cpu(rsp->SecurityMode);
    server->capabilities = le32_to_cpu(rsp->Capabilities);
    /* Internal types */
    server->capabilities |= SMB2_NT_FIND | SMB2_LARGE_FILES;

    security_blob = smb2_get_data_area_len(&blob_offset, &blob_length,
                           &rsp->hdr);
    if (blob_length == 0) {
        cERROR(1, "missing security blob on negprot");
        rc = -EIO;
        goto neg_exit;
    }

    cFYI(1, "sec_flags 0x%x", sec_flags);
    if (sec_flags & CIFSSEC_MUST_SIGN) {
        cFYI(1, "Signing required");
        if (!(server->sec_mode & (SMB2_NEGOTIATE_SIGNING_REQUIRED |
              SMB2_NEGOTIATE_SIGNING_ENABLED))) {
            cERROR(1, "signing required but server lacks support");
            rc = -EOPNOTSUPP;
            goto neg_exit;
        }
        server->sec_mode |= SECMODE_SIGN_REQUIRED;
    } else if (sec_flags & CIFSSEC_MAY_SIGN) {
        cFYI(1, "Signing optional");
        if (server->sec_mode & SMB2_NEGOTIATE_SIGNING_REQUIRED) {
            cFYI(1, "Server requires signing");
            server->sec_mode |= SECMODE_SIGN_REQUIRED;
        } else {
            server->sec_mode &=
                ~(SECMODE_SIGN_ENABLED | SECMODE_SIGN_REQUIRED);
        }
    } else {
        cFYI(1, "Signing disabled");
        if (server->sec_mode & SMB2_NEGOTIATE_SIGNING_REQUIRED) {
            cERROR(1, "Server requires packet signing to be enabled"
                  " in /proc/fs/cifs/SecurityFlags.");
            rc = -EOPNOTSUPP;
            goto neg_exit;
        }
        server->sec_mode &=
            ~(SECMODE_SIGN_ENABLED | SECMODE_SIGN_REQUIRED);
    }

#ifdef CONFIG_SMB2_ASN1  /* BB REMOVEME when updated asn1.c ready */
    rc = decode_neg_token_init(security_blob, blob_length,
                   &server->sec_type);
    if (rc == 1)
        rc = 0;
    else if (rc == 0) {
        rc = -EIO;
        goto neg_exit;
    }
#endif

neg_exit:
    free_rsp_buf(resp_buftype, rsp);
    return rc;
}

int
SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
        const struct nls_table *nls_cp)
{
    struct smb2_sess_setup_req *req;
    struct smb2_sess_setup_rsp *rsp = NULL;
    struct kvec iov[2];
    int rc = 0;
    int resp_buftype;
    __le32 phase = NtLmNegotiate; /* NTLMSSP, if needed, is multistage */
    struct TCP_Server_Info *server;
    unsigned int sec_flags;
    u8 temp = 0;
    u16 blob_length = 0;
    char *security_blob;
    char *ntlmssp_blob = NULL;
    bool use_spnego = false; /* else use raw ntlmssp */

    cFYI(1, "Session Setup");

    if (ses->server)
        server = ses->server;
    else {
        rc = -EIO;
        return rc;
    }

    /*
     * If memory allocation is successful, caller of this function
     * frees it.
     */
    ses->ntlmssp = kmalloc(sizeof(struct ntlmssp_auth), GFP_KERNEL);
    if (!ses->ntlmssp)
        return -ENOMEM;

    ses->server->secType = RawNTLMSSP;

ssetup_ntlmssp_authenticate:
    if (phase == NtLmChallenge)
        phase = NtLmAuthenticate; /* if ntlmssp, now final phase */

    rc = small_smb2_init(SMB2_SESSION_SETUP, NULL, (void **) &req);
    if (rc)
        return rc;

    /* if any of auth flags (ie not sign or seal) are overriden use them */
    if (ses->overrideSecFlg & (~(CIFSSEC_MUST_SIGN | CIFSSEC_MUST_SEAL)))
        sec_flags = ses->overrideSecFlg;  /* BB FIXME fix sign flags?*/
    else /* if override flags set only sign/seal OR them with global auth */
        sec_flags = global_secflags | ses->overrideSecFlg;

    cFYI(1, "sec_flags 0x%x", sec_flags);

    req->hdr.SessionId = 0; /* First session, not a reauthenticate */
    req->VcNumber = 0; /* MBZ */
    /* to enable echos and oplocks */
    req->hdr.CreditRequest = cpu_to_le16(3);

    /* only one of SMB2 signing flags may be set in SMB2 request */
    if ((sec_flags & CIFSSEC_MUST_SIGN) == CIFSSEC_MUST_SIGN)
        temp = SMB2_NEGOTIATE_SIGNING_REQUIRED;
    else if (ses->server->sec_mode & SMB2_NEGOTIATE_SIGNING_REQUIRED)
        temp = SMB2_NEGOTIATE_SIGNING_REQUIRED;
    else if (sec_flags & CIFSSEC_MAY_SIGN) /* MAY_SIGN is a single flag */
        temp = SMB2_NEGOTIATE_SIGNING_ENABLED;

    req->SecurityMode = temp;
    req->Capabilities = 0;
    req->Channel = 0; /* MBZ */

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field and 1 for pad */
    iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;
    if (phase == NtLmNegotiate) {
        ntlmssp_blob = kmalloc(sizeof(struct _NEGOTIATE_MESSAGE),
                       GFP_KERNEL);
        if (ntlmssp_blob == NULL) {
            rc = -ENOMEM;
            goto ssetup_exit;
        }
        build_ntlmssp_negotiate_blob(ntlmssp_blob, ses);
        if (use_spnego) {
            /* blob_length = build_spnego_ntlmssp_blob(
                    &security_blob,
                    sizeof(struct _NEGOTIATE_MESSAGE),
                    ntlmssp_blob); */
            /* BB eventually need to add this */
            cERROR(1, "spnego not supported for SMB2 yet");
            rc = -EOPNOTSUPP;
            kfree(ntlmssp_blob);
            goto ssetup_exit;
        } else {
            blob_length = sizeof(struct _NEGOTIATE_MESSAGE);
            /* with raw NTLMSSP we don't encapsulate in SPNEGO */
            security_blob = ntlmssp_blob;
        }
    } else if (phase == NtLmAuthenticate) {
        req->hdr.SessionId = ses->Suid;
        ntlmssp_blob = kzalloc(sizeof(struct _NEGOTIATE_MESSAGE) + 500,
                       GFP_KERNEL);
        if (ntlmssp_blob == NULL) {
            cERROR(1, "failed to malloc ntlmssp blob");
            rc = -ENOMEM;
            goto ssetup_exit;
        }
        rc = build_ntlmssp_auth_blob(ntlmssp_blob, &blob_length, ses,
                         nls_cp);
        if (rc) {
            cFYI(1, "build_ntlmssp_auth_blob failed %d", rc);
            goto ssetup_exit; /* BB double check error handling */
        }
        if (use_spnego) {
            /* blob_length = build_spnego_ntlmssp_blob(
                            &security_blob,
                            blob_length,
                            ntlmssp_blob); */
            cERROR(1, "spnego not supported for SMB2 yet");
            rc = -EOPNOTSUPP;
            kfree(ntlmssp_blob);
            goto ssetup_exit;
        } else {
            security_blob = ntlmssp_blob;
        }
    } else {
        cERROR(1, "illegal ntlmssp phase");
        rc = -EIO;
        goto ssetup_exit;
    }

    /* Testing shows that buffer offset must be at location of Buffer[0] */
    req->SecurityBufferOffset =
                cpu_to_le16(sizeof(struct smb2_sess_setup_req) -
                        1 /* pad */ - 4 /* rfc1001 len */);
    req->SecurityBufferLength = cpu_to_le16(blob_length);
    iov[1].iov_base = security_blob;
    iov[1].iov_len = blob_length;

    inc_rfc1001_len(req, blob_length - 1 /* pad */);

    /* BB add code to build os and lm fields */

    rc = SendReceive2(xid, ses, iov, 2, &resp_buftype, CIFS_LOG_ERROR);

    kfree(security_blob);
    rsp = (struct smb2_sess_setup_rsp *)iov[0].iov_base;
    if (resp_buftype != CIFS_NO_BUFFER &&
        rsp->hdr.Status == STATUS_MORE_PROCESSING_REQUIRED) {
        if (phase != NtLmNegotiate) {
            cERROR(1, "Unexpected more processing error");
            goto ssetup_exit;
        }
        if (offsetof(struct smb2_sess_setup_rsp, Buffer) - 4 !=
                le16_to_cpu(rsp->SecurityBufferOffset)) {
            cERROR(1, "Invalid security buffer offset %d",
                  le16_to_cpu(rsp->SecurityBufferOffset));
            rc = -EIO;
            goto ssetup_exit;
        }

        /* NTLMSSP Negotiate sent now processing challenge (response) */
        phase = NtLmChallenge; /* process ntlmssp challenge */
        rc = 0; /* MORE_PROCESSING is not an error here but expected */
        ses->Suid = rsp->hdr.SessionId;
        rc = decode_ntlmssp_challenge(rsp->Buffer,
                le16_to_cpu(rsp->SecurityBufferLength), ses);
    }

    /*
     * BB eventually add code for SPNEGO decoding of NtlmChallenge blob,
     * but at least the raw NTLMSSP case works.
     */
    /*
     * No tcon so can't do
     * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
     */
    if (rc != 0)
        goto ssetup_exit;

    ses->session_flags = le16_to_cpu(rsp->SessionFlags);
ssetup_exit:
    free_rsp_buf(resp_buftype, rsp);

    /* if ntlmssp, and negotiate succeeded, proceed to authenticate phase */
    if ((phase == NtLmChallenge) && (rc == 0))
        goto ssetup_ntlmssp_authenticate;
    return rc;
}

int
SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
{
    struct smb2_logoff_req *req; /* response is also trivial struct */
    int rc = 0;
    struct TCP_Server_Info *server;

    cFYI(1, "disconnect session %p", ses);

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    rc = small_smb2_init(SMB2_LOGOFF, NULL, (void **) &req);
    if (rc)
        return rc;

     /* since no tcon, smb2_init can not do this, so do here */
    req->hdr.SessionId = ses->Suid;
    if (server->sec_mode & SECMODE_SIGN_REQUIRED)
        req->hdr.Flags |= SMB2_FLAGS_SIGNED;

    rc = SendReceiveNoRsp(xid, ses, (char *) &req->hdr, 0);
    /*
     * No tcon so can't do
     * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
     */
    return rc;
}

static inline void cifs_stats_fail_inc(struct cifs_tcon *tcon, uint16_t code)
{
    cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_failed[code]);
}

#define MAX_SHARENAME_LENGTH (255 /* server */ + 80 /* share */ + 1 /* NULL */)

int
SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
      struct cifs_tcon *tcon, const struct nls_table *cp)
{
    struct smb2_tree_connect_req *req;
    struct smb2_tree_connect_rsp *rsp = NULL;
    struct kvec iov[2];
    int rc = 0;
    int resp_buftype;
    int unc_path_len;
    struct TCP_Server_Info *server;
    __le16 *unc_path = NULL;

    cFYI(1, "TCON");

    if ((ses->server) && tree)
        server = ses->server;
    else
        return -EIO;

    if (tcon && tcon->bad_network_name)
        return -ENOENT;

    unc_path = kmalloc(MAX_SHARENAME_LENGTH * 2, GFP_KERNEL);
    if (unc_path == NULL)
        return -ENOMEM;

    unc_path_len = cifs_strtoUTF16(unc_path, tree, strlen(tree), cp) + 1;
    unc_path_len *= 2;
    if (unc_path_len < 2) {
        kfree(unc_path);
        return -EINVAL;
    }

    rc = small_smb2_init(SMB2_TREE_CONNECT, tcon, (void **) &req);
    if (rc) {
        kfree(unc_path);
        return rc;
    }

    if (tcon == NULL) {
        /* since no tcon, smb2_init can not do this, so do here */
        req->hdr.SessionId = ses->Suid;
        /* if (ses->server->sec_mode & SECMODE_SIGN_REQUIRED)
            req->hdr.Flags |= SMB2_FLAGS_SIGNED; */
    }

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field and 1 for pad */
    iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;

    /* Testing shows that buffer offset must be at location of Buffer[0] */
    req->PathOffset = cpu_to_le16(sizeof(struct smb2_tree_connect_req)
            - 1 /* pad */ - 4 /* do not count rfc1001 len field */);
    req->PathLength = cpu_to_le16(unc_path_len - 2);
    iov[1].iov_base = unc_path;
    iov[1].iov_len = unc_path_len;

    inc_rfc1001_len(req, unc_path_len - 1 /* pad */);

    rc = SendReceive2(xid, ses, iov, 2, &resp_buftype, 0);
    rsp = (struct smb2_tree_connect_rsp *)iov[0].iov_base;

    if (rc != 0) {
        if (tcon) {
            cifs_stats_fail_inc(tcon, SMB2_TREE_CONNECT_HE);
            tcon->need_reconnect = true;
        }
        goto tcon_error_exit;
    }

    if (tcon == NULL) {
        ses->ipc_tid = rsp->hdr.TreeId;
        goto tcon_exit;
    }

    if (rsp->ShareType & SMB2_SHARE_TYPE_DISK)
        cFYI(1, "connection to disk share");
    else if (rsp->ShareType & SMB2_SHARE_TYPE_PIPE) {
        tcon->ipc = true;
        cFYI(1, "connection to pipe share");
    } else if (rsp->ShareType & SMB2_SHARE_TYPE_PRINT) {
        tcon->print = true;
        cFYI(1, "connection to printer");
    } else {
        cERROR(1, "unknown share type %d", rsp->ShareType);
        rc = -EOPNOTSUPP;
        goto tcon_error_exit;
    }

    tcon->share_flags = le32_to_cpu(rsp->ShareFlags);
    tcon->maximal_access = le32_to_cpu(rsp->MaximalAccess);
    tcon->tidStatus = CifsGood;
    tcon->need_reconnect = false;
    tcon->tid = rsp->hdr.TreeId;
    strncpy(tcon->treeName, tree, MAX_TREE_SIZE);

    if ((rsp->Capabilities & SMB2_SHARE_CAP_DFS) &&
        ((tcon->share_flags & SHI1005_FLAGS_DFS) == 0))
        cERROR(1, "DFS capability contradicts DFS flag");

tcon_exit:
    free_rsp_buf(resp_buftype, rsp);
    kfree(unc_path);
    return rc;

tcon_error_exit:
    if (rsp->hdr.Status == STATUS_BAD_NETWORK_NAME) {
        cERROR(1, "BAD_NETWORK_NAME: %s", tree);
        tcon->bad_network_name = true;
    }
    goto tcon_exit;
}

int
SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon)
{
    struct smb2_tree_disconnect_req *req; /* response is trivial */
    int rc = 0;
    struct TCP_Server_Info *server;
    struct cifs_ses *ses = tcon->ses;

    cFYI(1, "Tree Disconnect");

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    if ((tcon->need_reconnect) || (tcon->ses->need_reconnect))
        return 0;

    rc = small_smb2_init(SMB2_TREE_DISCONNECT, tcon, (void **) &req);
    if (rc)
        return rc;

    rc = SendReceiveNoRsp(xid, ses, (char *)&req->hdr, 0);
    if (rc)
        cifs_stats_fail_inc(tcon, SMB2_TREE_DISCONNECT_HE);

    return rc;
}

static struct create_lease *
create_lease_buf(u8 *lease_key, u8 oplock)
{
    struct create_lease *buf;

    buf = kmalloc(sizeof(struct create_lease), GFP_KERNEL);
    if (!buf)
        return NULL;

    memset(buf, 0, sizeof(struct create_lease));

    buf->lcontext.LeaseKeyLow = cpu_to_le64(*((u64 *)lease_key));
    buf->lcontext.LeaseKeyHigh = cpu_to_le64(*((u64 *)(lease_key + 8)));
    if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE)
        buf->lcontext.LeaseState = SMB2_LEASE_WRITE_CACHING |
                       SMB2_LEASE_READ_CACHING;
    else if (oplock == SMB2_OPLOCK_LEVEL_II)
        buf->lcontext.LeaseState = SMB2_LEASE_READ_CACHING;
    else if (oplock == SMB2_OPLOCK_LEVEL_BATCH)
        buf->lcontext.LeaseState = SMB2_LEASE_HANDLE_CACHING |
                       SMB2_LEASE_READ_CACHING |
                       SMB2_LEASE_WRITE_CACHING;

    buf->ccontext.DataOffset = cpu_to_le16(offsetof
                    (struct create_lease, lcontext));
    buf->ccontext.DataLength = cpu_to_le32(sizeof(struct lease_context));
    buf->ccontext.NameOffset = cpu_to_le16(offsetof
                (struct create_lease, Name));
    buf->ccontext.NameLength = cpu_to_le16(4);
    buf->Name[0] = 'R';
    buf->Name[1] = 'q';
    buf->Name[2] = 'L';
    buf->Name[3] = 's';
    return buf;
}

static __u8
parse_lease_state(struct smb2_create_rsp *rsp)
{
    char *data_offset;
    struct create_lease *lc;
    bool found = false;

    data_offset = (char *)rsp;
    data_offset += 4 + le32_to_cpu(rsp->CreateContextsOffset);
    lc = (struct create_lease *)data_offset;
    do {
        char *name = le16_to_cpu(lc->ccontext.NameOffset) + (char *)lc;
        if (le16_to_cpu(lc->ccontext.NameLength) != 4 ||
            strncmp(name, "RqLs", 4)) {
            lc = (struct create_lease *)((char *)lc
                    + le32_to_cpu(lc->ccontext.Next));
            continue;
        }
        if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
            return SMB2_OPLOCK_LEVEL_NOCHANGE;
        found = true;
        break;
    } while (le32_to_cpu(lc->ccontext.Next) != 0);

    if (!found)
        return 0;

    return smb2_map_lease_to_oplock(lc->lcontext.LeaseState);
}

int
SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
      u64 *persistent_fid, u64 *volatile_fid, __u32 desired_access,
      __u32 create_disposition, __u32 file_attributes, __u32 create_options,
      __u8 *oplock, struct smb2_file_all_info *buf)
{
    struct smb2_create_req *req;
    struct smb2_create_rsp *rsp;
    struct TCP_Server_Info *server;
    struct cifs_ses *ses = tcon->ses;
    struct kvec iov[3];
    int resp_buftype;
    int uni_path_len;
    __le16 *copy_path = NULL;
    int copy_size;
    int rc = 0;
    int num_iovecs = 2;

    cFYI(1, "create/open");

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    rc = small_smb2_init(SMB2_CREATE, tcon, (void **) &req);
    if (rc)
        return rc;

    req->ImpersonationLevel = IL_IMPERSONATION;
    req->DesiredAccess = cpu_to_le32(desired_access);
    /* File attributes ignored on open (used in create though) */
    req->FileAttributes = cpu_to_le32(file_attributes);
    req->ShareAccess = FILE_SHARE_ALL_LE;
    req->CreateDisposition = cpu_to_le32(create_disposition);
    req->CreateOptions = cpu_to_le32(create_options);
    uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;
    req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req)
            - 8 /* pad */ - 4 /* do not count rfc1001 len field */);

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov[0].iov_len = get_rfc1002_length(req) + 4;

    /* MUST set path len (NameLength) to 0 opening root of share */
    if (uni_path_len >= 4) {
        req->NameLength = cpu_to_le16(uni_path_len - 2);
        /* -1 since last byte is buf[0] which is sent below (path) */
        iov[0].iov_len--;
        if (uni_path_len % 8 != 0) {
            copy_size = uni_path_len / 8 * 8;
            if (copy_size < uni_path_len)
                copy_size += 8;

            copy_path = kzalloc(copy_size, GFP_KERNEL);
            if (!copy_path)
                return -ENOMEM;
            memcpy((char *)copy_path, (const char *)path,
                uni_path_len);
            uni_path_len = copy_size;
            path = copy_path;
        }

        iov[1].iov_len = uni_path_len;
        iov[1].iov_base = path;
        /*
         * -1 since last byte is buf[0] which was counted in
         * smb2_buf_len.
         */
        inc_rfc1001_len(req, uni_path_len - 1);
    } else {
        iov[0].iov_len += 7;
        req->hdr.smb2_buf_length = cpu_to_be32(be32_to_cpu(
                req->hdr.smb2_buf_length) + 8 - 1);
        num_iovecs = 1;
        req->NameLength = 0;
    }

    if (!server->oplocks)
        *oplock = SMB2_OPLOCK_LEVEL_NONE;

    if (!(tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING) ||
        *oplock == SMB2_OPLOCK_LEVEL_NONE)
        req->RequestedOplockLevel = *oplock;
    else {
        iov[num_iovecs].iov_base = create_lease_buf(oplock+1, *oplock);
        if (iov[num_iovecs].iov_base == NULL) {
            cifs_small_buf_release(req);
            kfree(copy_path);
            return -ENOMEM;
        }
        iov[num_iovecs].iov_len = sizeof(struct create_lease);
        req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_LEASE;
        req->CreateContextsOffset = cpu_to_le32(
            sizeof(struct smb2_create_req) - 4 - 8 +
            iov[num_iovecs-1].iov_len);
        req->CreateContextsLength = cpu_to_le32(
            sizeof(struct create_lease));
        inc_rfc1001_len(&req->hdr, sizeof(struct create_lease));
        num_iovecs++;
    }

    rc = SendReceive2(xid, ses, iov, num_iovecs, &resp_buftype, 0);
    rsp = (struct smb2_create_rsp *)iov[0].iov_base;

    if (rc != 0) {
        cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
        goto creat_exit;
    }

    *persistent_fid = rsp->PersistentFileId;
    *volatile_fid = rsp->VolatileFileId;

    if (buf) {
        memcpy(buf, &rsp->CreationTime, 32);
        buf->AllocationSize = rsp->AllocationSize;
        buf->EndOfFile = rsp->EndofFile;
        buf->Attributes = rsp->FileAttributes;
        buf->NumberOfLinks = cpu_to_le32(1);
        buf->DeletePending = 0;
    }

    if (rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE)
        *oplock = parse_lease_state(rsp);
    else
        *oplock = rsp->OplockLevel;
creat_exit:
    kfree(copy_path);
    free_rsp_buf(resp_buftype, rsp);
    return rc;
}

int
SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
       u64 persistent_fid, u64 volatile_fid)
{
    struct smb2_close_req *req;
    struct smb2_close_rsp *rsp;
    struct TCP_Server_Info *server;
    struct cifs_ses *ses = tcon->ses;
    struct kvec iov[1];
    int resp_buftype;
    int rc = 0;

    cFYI(1, "Close");

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    rc = small_smb2_init(SMB2_CLOSE, tcon, (void **) &req);
    if (rc)
        return rc;

    req->PersistentFileId = persistent_fid;
    req->VolatileFileId = volatile_fid;

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov[0].iov_len = get_rfc1002_length(req) + 4;

    rc = SendReceive2(xid, ses, iov, 1, &resp_buftype, 0);
    rsp = (struct smb2_close_rsp *)iov[0].iov_base;

    if (rc != 0) {
        if (tcon)
            cifs_stats_fail_inc(tcon, SMB2_CLOSE_HE);
        goto close_exit;
    }

    /* BB FIXME - decode close response, update inode for caching */

close_exit:
    free_rsp_buf(resp_buftype, rsp);
    return rc;
}

static int
validate_buf(unsigned int offset, unsigned int buffer_length,
         struct smb2_hdr *hdr, unsigned int min_buf_size)

{
    unsigned int smb_len = be32_to_cpu(hdr->smb2_buf_length);
    char *end_of_smb = smb_len + 4 /* RFC1001 length field */ + (char *)hdr;
    char *begin_of_buf = 4 /* RFC1001 len field */ + offset + (char *)hdr;
    char *end_of_buf = begin_of_buf + buffer_length;


    if (buffer_length < min_buf_size) {
        cERROR(1, "buffer length %d smaller than minimum size %d",
               buffer_length, min_buf_size);
        return -EINVAL;
    }

    /* check if beyond RFC1001 maximum length */
    if ((smb_len > 0x7FFFFF) || (buffer_length > 0x7FFFFF)) {
        cERROR(1, "buffer length %d or smb length %d too large",
               buffer_length, smb_len);
        return -EINVAL;
    }

    if ((begin_of_buf > end_of_smb) || (end_of_buf > end_of_smb)) {
        cERROR(1, "illegal server response, bad offset to data");
        return -EINVAL;
    }

    return 0;
}

/*
 * If SMB buffer fields are valid, copy into temporary buffer to hold result.
 * Caller must free buffer.
 */
static int
validate_and_copy_buf(unsigned int offset, unsigned int buffer_length,
              struct smb2_hdr *hdr, unsigned int minbufsize,
              char *data)

{
    char *begin_of_buf = 4 /* RFC1001 len field */ + offset + (char *)hdr;
    int rc;

    if (!data)
        return -EINVAL;

    rc = validate_buf(offset, buffer_length, hdr, minbufsize);
    if (rc)
        return rc;

    memcpy(data, begin_of_buf, buffer_length);

    return 0;
}

static int
query_info(const unsigned int xid, struct cifs_tcon *tcon,
       u64 persistent_fid, u64 volatile_fid, u8 info_class,
       size_t output_len, size_t min_len, void *data)
{
    struct smb2_query_info_req *req;
    struct smb2_query_info_rsp *rsp = NULL;
    struct kvec iov[2];
    int rc = 0;
    int resp_buftype;
    struct TCP_Server_Info *server;
    struct cifs_ses *ses = tcon->ses;

    cFYI(1, "Query Info");

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    rc = small_smb2_init(SMB2_QUERY_INFO, tcon, (void **) &req);
    if (rc)
        return rc;

    req->InfoType = SMB2_O_INFO_FILE;
    req->FileInfoClass = info_class;
    req->PersistentFileId = persistent_fid;
    req->VolatileFileId = volatile_fid;
    /* 4 for rfc1002 length field and 1 for Buffer */
    req->InputBufferOffset =
        cpu_to_le16(sizeof(struct smb2_query_info_req) - 1 - 4);
    req->OutputBufferLength = cpu_to_le32(output_len);

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov[0].iov_len = get_rfc1002_length(req) + 4;

    rc = SendReceive2(xid, ses, iov, 1, &resp_buftype, 0);
    rsp = (struct smb2_query_info_rsp *)iov[0].iov_base;

    if (rc) {
        cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
        goto qinf_exit;
    }

    rc = validate_and_copy_buf(le16_to_cpu(rsp->OutputBufferOffset),
                   le32_to_cpu(rsp->OutputBufferLength),
                   &rsp->hdr, min_len, data);

qinf_exit:
    free_rsp_buf(resp_buftype, rsp);
    return rc;
}

int
SMB2_query_info(const unsigned int xid, struct cifs_tcon *tcon,
        u64 persistent_fid, u64 volatile_fid,
        struct smb2_file_all_info *data)
{
    return query_info(xid, tcon, persistent_fid, volatile_fid,
              FILE_ALL_INFORMATION,
              sizeof(struct smb2_file_all_info) + MAX_NAME * 2,
              sizeof(struct smb2_file_all_info), data);
}

int
SMB2_get_srv_num(const unsigned int xid, struct cifs_tcon *tcon,
         u64 persistent_fid, u64 volatile_fid, __le64 *uniqueid)
{
    return query_info(xid, tcon, persistent_fid, volatile_fid,
              FILE_INTERNAL_INFORMATION,
              sizeof(struct smb2_file_internal_info),
              sizeof(struct smb2_file_internal_info), uniqueid);
}

/*
 * This is a no-op for now. We're not really interested in the reply, but
 * rather in the fact that the server sent one and that server->lstrp
 * gets updated.
 *
 * FIXME: maybe we should consider checking that the reply matches request?
 */
static void
smb2_echo_callback(struct mid_q_entry *mid)
{
    struct TCP_Server_Info *server = mid->callback_data;
    struct smb2_echo_rsp *smb2 = (struct smb2_echo_rsp *)mid->resp_buf;
    unsigned int credits_received = 1;

    if (mid->mid_state == MID_RESPONSE_RECEIVED)
        credits_received = le16_to_cpu(smb2->hdr.CreditRequest);

    DeleteMidQEntry(mid);
    add_credits(server, credits_received, CIFS_ECHO_OP);
}

int
SMB2_echo(struct TCP_Server_Info *server)
{
    struct smb2_echo_req *req;
    int rc = 0;
    struct kvec iov;
    struct smb_rqst rqst = { .rq_iov = &iov,
                 .rq_nvec = 1 };

    cFYI(1, "In echo request");

    rc = small_smb2_init(SMB2_ECHO, NULL, (void **)&req);
    if (rc)
        return rc;

    req->hdr.CreditRequest = cpu_to_le16(1);

    iov.iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov.iov_len = get_rfc1002_length(req) + 4;

    rc = cifs_call_async(server, &rqst, NULL, smb2_echo_callback, server,
                 CIFS_ECHO_OP);
    if (rc)
        cFYI(1, "Echo request failed: %d", rc);

    cifs_small_buf_release(req);
    return rc;
}

int
SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
       u64 volatile_fid)
{
    struct smb2_flush_req *req;
    struct TCP_Server_Info *server;
    struct cifs_ses *ses = tcon->ses;
    struct kvec iov[1];
    int resp_buftype;
    int rc = 0;

    cFYI(1, "Flush");

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    rc = small_smb2_init(SMB2_FLUSH, tcon, (void **) &req);
    if (rc)
        return rc;

    req->PersistentFileId = persistent_fid;
    req->VolatileFileId = volatile_fid;

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov[0].iov_len = get_rfc1002_length(req) + 4;

    rc = SendReceive2(xid, ses, iov, 1, &resp_buftype, 0);

    if ((rc != 0) && tcon)
        cifs_stats_fail_inc(tcon, SMB2_FLUSH_HE);

    free_rsp_buf(resp_buftype, iov[0].iov_base);
    return rc;
}

/*
 * To form a chain of read requests, any read requests after the first should
 * have the end_of_chain boolean set to true.
 */
static int
smb2_new_read_req(struct kvec *iov, struct cifs_io_parms *io_parms,
          unsigned int remaining_bytes, int request_type)
{
    int rc = -EACCES;
    struct smb2_read_req *req = NULL;

    rc = small_smb2_init(SMB2_READ, io_parms->tcon, (void **) &req);
    if (rc)
        return rc;
    if (io_parms->tcon->ses->server == NULL)
        return -ECONNABORTED;

    req->hdr.ProcessId = cpu_to_le32(io_parms->pid);

    req->PersistentFileId = io_parms->persistent_fid;
    req->VolatileFileId = io_parms->volatile_fid;
    req->ReadChannelInfoOffset = 0; /* reserved */
    req->ReadChannelInfoLength = 0; /* reserved */
    req->Channel = 0; /* reserved */
    req->MinimumCount = 0;
    req->Length = cpu_to_le32(io_parms->length);
    req->Offset = cpu_to_le64(io_parms->offset);

    if (request_type & CHAINED_REQUEST) {
        if (!(request_type & END_OF_CHAIN)) {
            /* 4 for rfc1002 length field */
            req->hdr.NextCommand =
                cpu_to_le32(get_rfc1002_length(req) + 4);
        } else /* END_OF_CHAIN */
            req->hdr.NextCommand = 0;
        if (request_type & RELATED_REQUEST) {
            req->hdr.Flags |= SMB2_FLAGS_RELATED_OPERATIONS;
            /*
             * Related requests use info from previous read request
             * in chain.
             */
            req->hdr.SessionId = 0xFFFFFFFF;
            req->hdr.TreeId = 0xFFFFFFFF;
            req->PersistentFileId = 0xFFFFFFFF;
            req->VolatileFileId = 0xFFFFFFFF;
        }
    }
    if (remaining_bytes > io_parms->length)
        req->RemainingBytes = cpu_to_le32(remaining_bytes);
    else
        req->RemainingBytes = 0;

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov[0].iov_len = get_rfc1002_length(req) + 4;
    return rc;
}

static void
smb2_readv_callback(struct mid_q_entry *mid)
{
    struct cifs_readdata *rdata = mid->callback_data;
    struct cifs_tcon *tcon = tlink_tcon(rdata->cfile->tlink);
    struct TCP_Server_Info *server = tcon->ses->server;
    struct smb2_hdr *buf = (struct smb2_hdr *)rdata->iov.iov_base;
    unsigned int credits_received = 1;
    struct smb_rqst rqst = { .rq_iov = &rdata->iov,
                 .rq_nvec = 1,
                 .rq_pages = rdata->pages,
                 .rq_npages = rdata->nr_pages,
                 .rq_pagesz = rdata->pagesz,
                 .rq_tailsz = rdata->tailsz };

    cFYI(1, "%s: mid=%llu state=%d result=%d bytes=%u", __func__,
        mid->mid, mid->mid_state, rdata->result, rdata->bytes);

    switch (mid->mid_state) {
    case MID_RESPONSE_RECEIVED:
        credits_received = le16_to_cpu(buf->CreditRequest);
        /* result already set, check signature */
        if (server->sec_mode &
            (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
            int rc;

            rc = smb2_verify_signature(&rqst, server);
            if (rc)
                cERROR(1, "SMB signature verification returned "
                       "error = %d", rc);
        }
        /* FIXME: should this be counted toward the initiating task? */
        task_io_account_read(rdata->bytes);
        cifs_stats_bytes_read(tcon, rdata->bytes);
        break;
    case MID_REQUEST_SUBMITTED:
    case MID_RETRY_NEEDED:
        rdata->result = -EAGAIN;
        break;
    default:
        if (rdata->result != -ENODATA)
            rdata->result = -EIO;
    }

    if (rdata->result)
        cifs_stats_fail_inc(tcon, SMB2_READ_HE);

    queue_work(cifsiod_wq, &rdata->work);
    DeleteMidQEntry(mid);
    add_credits(server, credits_received, 0);
}

/* smb2_async_readv - send an async write, and set up mid to handle result */
int
smb2_async_readv(struct cifs_readdata *rdata)
{
    int rc;
    struct smb2_hdr *buf;
    struct cifs_io_parms io_parms;
    struct smb_rqst rqst = { .rq_iov = &rdata->iov,
                 .rq_nvec = 1 };

    cFYI(1, "%s: offset=%llu bytes=%u", __func__,
        rdata->offset, rdata->bytes);

    io_parms.tcon = tlink_tcon(rdata->cfile->tlink);
    io_parms.offset = rdata->offset;
    io_parms.length = rdata->bytes;
    io_parms.persistent_fid = rdata->cfile->fid.persistent_fid;
    io_parms.volatile_fid = rdata->cfile->fid.volatile_fid;
    io_parms.pid = rdata->pid;
    rc = smb2_new_read_req(&rdata->iov, &io_parms, 0, 0);
    if (rc)
        return rc;

    buf = (struct smb2_hdr *)rdata->iov.iov_base;
    /* 4 for rfc1002 length field */
    rdata->iov.iov_len = get_rfc1002_length(rdata->iov.iov_base) + 4;

    kref_get(&rdata->refcount);
    rc = cifs_call_async(io_parms.tcon->ses->server, &rqst,
                 cifs_readv_receive, smb2_readv_callback,
                 rdata, 0);
    if (rc) {
        kref_put(&rdata->refcount, cifs_readdata_release);
        cifs_stats_fail_inc(io_parms.tcon, SMB2_READ_HE);
    }

    cifs_small_buf_release(buf);
    return rc;
}

int
SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
      unsigned int *nbytes, char **buf, int *buf_type)
{
    int resp_buftype, rc = -EACCES;
    struct smb2_read_rsp *rsp = NULL;
    struct kvec iov[1];

    *nbytes = 0;
    rc = smb2_new_read_req(iov, io_parms, 0, 0);
    if (rc)
        return rc;

    rc = SendReceive2(xid, io_parms->tcon->ses, iov, 1,
              &resp_buftype, CIFS_LOG_ERROR);

    rsp = (struct smb2_read_rsp *)iov[0].iov_base;

    if (rsp->hdr.Status == STATUS_END_OF_FILE) {
        free_rsp_buf(resp_buftype, iov[0].iov_base);
        return 0;
    }

    if (rc) {
        cifs_stats_fail_inc(io_parms->tcon, SMB2_READ_HE);
        cERROR(1, "Send error in read = %d", rc);
    } else {
        *nbytes = le32_to_cpu(rsp->DataLength);
        if ((*nbytes > CIFS_MAX_MSGSIZE) ||
            (*nbytes > io_parms->length)) {
            cFYI(1, "bad length %d for count %d", *nbytes,
                io_parms->length);
            rc = -EIO;
            *nbytes = 0;
        }
    }

    if (*buf) {
        memcpy(*buf, (char *)rsp->hdr.ProtocolId + rsp->DataOffset,
               *nbytes);
        free_rsp_buf(resp_buftype, iov[0].iov_base);
    } else if (resp_buftype != CIFS_NO_BUFFER) {
        *buf = iov[0].iov_base;
        if (resp_buftype == CIFS_SMALL_BUFFER)
            *buf_type = CIFS_SMALL_BUFFER;
        else if (resp_buftype == CIFS_LARGE_BUFFER)
            *buf_type = CIFS_LARGE_BUFFER;
    }
    return rc;
}

/*
 * Check the mid_state and signature on received buffer (if any), and queue the
 * workqueue completion task.
 */
static void
smb2_writev_callback(struct mid_q_entry *mid)
{
    struct cifs_writedata *wdata = mid->callback_data;
    struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
    unsigned int written;
    struct smb2_write_rsp *rsp = (struct smb2_write_rsp *)mid->resp_buf;
    unsigned int credits_received = 1;

    switch (mid->mid_state) {
    case MID_RESPONSE_RECEIVED:
        credits_received = le16_to_cpu(rsp->hdr.CreditRequest);
        wdata->result = smb2_check_receive(mid, tcon->ses->server, 0);
        if (wdata->result != 0)
            break;

        written = le32_to_cpu(rsp->DataLength);
        /*
         * Mask off high 16 bits when bytes written as returned
         * by the server is greater than bytes requested by the
         * client. OS/2 servers are known to set incorrect
         * CountHigh values.
         */
        if (written > wdata->bytes)
            written &= 0xFFFF;

        if (written < wdata->bytes)
            wdata->result = -ENOSPC;
        else
            wdata->bytes = written;
        break;
    case MID_REQUEST_SUBMITTED:
    case MID_RETRY_NEEDED:
        wdata->result = -EAGAIN;
        break;
    default:
        wdata->result = -EIO;
        break;
    }

    if (wdata->result)
        cifs_stats_fail_inc(tcon, SMB2_WRITE_HE);

    queue_work(cifsiod_wq, &wdata->work);
    DeleteMidQEntry(mid);
    add_credits(tcon->ses->server, credits_received, 0);
}

/* smb2_async_writev - send an async write, and set up mid to handle result */
int
smb2_async_writev(struct cifs_writedata *wdata)
{
    int rc = -EACCES;
    struct smb2_write_req *req = NULL;
    struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
    struct kvec iov;
    struct smb_rqst rqst;

    rc = small_smb2_init(SMB2_WRITE, tcon, (void **) &req);
    if (rc)
        goto async_writev_out;

    req->hdr.ProcessId = cpu_to_le32(wdata->cfile->pid);

    req->PersistentFileId = wdata->cfile->fid.persistent_fid;
    req->VolatileFileId = wdata->cfile->fid.volatile_fid;
    req->WriteChannelInfoOffset = 0;
    req->WriteChannelInfoLength = 0;
    req->Channel = 0;
    req->Offset = cpu_to_le64(wdata->offset);
    /* 4 for rfc1002 length field */
    req->DataOffset = cpu_to_le16(
                offsetof(struct smb2_write_req, Buffer) - 4);
    req->RemainingBytes = 0;

    /* 4 for rfc1002 length field and 1 for Buffer */
    iov.iov_len = get_rfc1002_length(req) + 4 - 1;
    iov.iov_base = req;

    rqst.rq_iov = &iov;
    rqst.rq_nvec = 1;
    rqst.rq_pages = wdata->pages;
    rqst.rq_npages = wdata->nr_pages;
    rqst.rq_pagesz = wdata->pagesz;
    rqst.rq_tailsz = wdata->tailsz;

    cFYI(1, "async write at %llu %u bytes", wdata->offset, wdata->bytes);

    req->Length = cpu_to_le32(wdata->bytes);

    inc_rfc1001_len(&req->hdr, wdata->bytes - 1 /* Buffer */);

    kref_get(&wdata->refcount);
    rc = cifs_call_async(tcon->ses->server, &rqst, NULL,
                smb2_writev_callback, wdata, 0);

    if (rc) {
        kref_put(&wdata->refcount, cifs_writedata_release);
        cifs_stats_fail_inc(tcon, SMB2_WRITE_HE);
    }

async_writev_out:
    cifs_small_buf_release(req);
    return rc;
}

/*
 * SMB2_write function gets iov pointer to kvec array with n_vec as a length.
 * The length field from io_parms must be at least 1 and indicates a number of
 * elements with data to write that begins with position 1 in iov array. All
 * data length is specified by count.
 */
int
SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms,
       unsigned int *nbytes, struct kvec *iov, int n_vec)
{
    int rc = 0;
    struct smb2_write_req *req = NULL;
    struct smb2_write_rsp *rsp = NULL;
    int resp_buftype;
    *nbytes = 0;

    if (n_vec < 1)
        return rc;

    rc = small_smb2_init(SMB2_WRITE, io_parms->tcon, (void **) &req);
    if (rc)
        return rc;

    if (io_parms->tcon->ses->server == NULL)
        return -ECONNABORTED;

    req->hdr.ProcessId = cpu_to_le32(io_parms->pid);

    req->PersistentFileId = io_parms->persistent_fid;
    req->VolatileFileId = io_parms->volatile_fid;
    req->WriteChannelInfoOffset = 0;
    req->WriteChannelInfoLength = 0;
    req->Channel = 0;
    req->Length = cpu_to_le32(io_parms->length);
    req->Offset = cpu_to_le64(io_parms->offset);
    /* 4 for rfc1002 length field */
    req->DataOffset = cpu_to_le16(
                offsetof(struct smb2_write_req, Buffer) - 4);
    req->RemainingBytes = 0;

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field and 1 for Buffer */
    iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;

    /* length of entire message including data to be written */
    inc_rfc1001_len(req, io_parms->length - 1 /* Buffer */);

    rc = SendReceive2(xid, io_parms->tcon->ses, iov, n_vec + 1,
              &resp_buftype, 0);
    rsp = (struct smb2_write_rsp *)iov[0].iov_base;

    if (rc) {
        cifs_stats_fail_inc(io_parms->tcon, SMB2_WRITE_HE);
        cERROR(1, "Send error in write = %d", rc);
    } else
        *nbytes = le32_to_cpu(rsp->DataLength);

    free_rsp_buf(resp_buftype, rsp);
    return rc;
}

static unsigned int
num_entries(char *bufstart, char *end_of_buf, char **lastentry, size_t size)
{
    int len;
    unsigned int entrycount = 0;
    unsigned int next_offset = 0;
    FILE_DIRECTORY_INFO *entryptr;

    if (bufstart == NULL)
        return 0;

    entryptr = (FILE_DIRECTORY_INFO *)bufstart;

    while (1) {
        entryptr = (FILE_DIRECTORY_INFO *)
                    ((char *)entryptr + next_offset);

        if ((char *)entryptr + size > end_of_buf) {
            cERROR(1, "malformed search entry would overflow");
            break;
        }

        len = le32_to_cpu(entryptr->FileNameLength);
        if ((char *)entryptr + len + size > end_of_buf) {
            cERROR(1, "directory entry name would overflow frame "
                  "end of buf %p", end_of_buf);
            break;
        }

        *lastentry = (char *)entryptr;
        entrycount++;

        next_offset = le32_to_cpu(entryptr->NextEntryOffset);
        if (!next_offset)
            break;
    }

    return entrycount;
}

/*
 * Readdir/FindFirst
 */
int
SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
             u64 persistent_fid, u64 volatile_fid, int index,
             struct cifs_search_info *srch_inf)
{
    struct smb2_query_directory_req *req;
    struct smb2_query_directory_rsp *rsp = NULL;
    struct kvec iov[2];
    int rc = 0;
    int len;
    int resp_buftype;
    unsigned char *bufptr;
    struct TCP_Server_Info *server;
    struct cifs_ses *ses = tcon->ses;
    __le16 asteriks = cpu_to_le16('*');
    char *end_of_smb;
    unsigned int output_size = CIFSMaxBufSize;
    size_t info_buf_size;

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    rc = small_smb2_init(SMB2_QUERY_DIRECTORY, tcon, (void **) &req);
    if (rc)
        return rc;

    switch (srch_inf->info_level) {
    case SMB_FIND_FILE_DIRECTORY_INFO:
        req->FileInformationClass = FILE_DIRECTORY_INFORMATION;
        info_buf_size = sizeof(FILE_DIRECTORY_INFO) - 1;
        break;
    case SMB_FIND_FILE_ID_FULL_DIR_INFO:
        req->FileInformationClass = FILEID_FULL_DIRECTORY_INFORMATION;
        info_buf_size = sizeof(SEARCH_ID_FULL_DIR_INFO) - 1;
        break;
    default:
        cERROR(1, "info level %u isn't supported",
               srch_inf->info_level);
        rc = -EINVAL;
        goto qdir_exit;
    }

    req->FileIndex = cpu_to_le32(index);
    req->PersistentFileId = persistent_fid;
    req->VolatileFileId = volatile_fid;

    len = 0x2;
    bufptr = req->Buffer;
    memcpy(bufptr, &asteriks, len);

    req->FileNameOffset =
        cpu_to_le16(sizeof(struct smb2_query_directory_req) - 1 - 4);
    req->FileNameLength = cpu_to_le16(len);
    /*
     * BB could be 30 bytes or so longer if we used SMB2 specific
     * buffer lengths, but this is safe and close enough.
     */
    output_size = min_t(unsigned int, output_size, server->maxBuf);
    output_size = min_t(unsigned int, output_size, 2 << 15);
    req->OutputBufferLength = cpu_to_le32(output_size);

    iov[0].iov_base = (char *)req;
    /* 4 for RFC1001 length and 1 for Buffer */
    iov[0].iov_len = get_rfc1002_length(req) + 4 - 1;

    iov[1].iov_base = (char *)(req->Buffer);
    iov[1].iov_len = len;

    inc_rfc1001_len(req, len - 1 /* Buffer */);

    rc = SendReceive2(xid, ses, iov, 2, &resp_buftype, 0);
    rsp = (struct smb2_query_directory_rsp *)iov[0].iov_base;

    if (rc) {
        cifs_stats_fail_inc(tcon, SMB2_QUERY_DIRECTORY_HE);
        goto qdir_exit;
    }

    rc = validate_buf(le16_to_cpu(rsp->OutputBufferOffset),
              le32_to_cpu(rsp->OutputBufferLength), &rsp->hdr,
              info_buf_size);
    if (rc)
        goto qdir_exit;

    srch_inf->unicode = true;

    if (srch_inf->ntwrk_buf_start) {
        if (srch_inf->smallBuf)
            cifs_small_buf_release(srch_inf->ntwrk_buf_start);
        else
            cifs_buf_release(srch_inf->ntwrk_buf_start);
    }
    srch_inf->ntwrk_buf_start = (char *)rsp;
    srch_inf->srch_entries_start = srch_inf->last_entry = 4 /* rfclen */ +
        (char *)&rsp->hdr + le16_to_cpu(rsp->OutputBufferOffset);
    /* 4 for rfc1002 length field */
    end_of_smb = get_rfc1002_length(rsp) + 4 + (char *)&rsp->hdr;
    srch_inf->entries_in_buffer =
            num_entries(srch_inf->srch_entries_start, end_of_smb,
                    &srch_inf->last_entry, info_buf_size);
    srch_inf->index_of_last_entry += srch_inf->entries_in_buffer;
    cFYI(1, "num entries %d last_index %lld srch start %p srch end %p",
        srch_inf->entries_in_buffer, srch_inf->index_of_last_entry,
        srch_inf->srch_entries_start, srch_inf->last_entry);
    if (resp_buftype == CIFS_LARGE_BUFFER)
        srch_inf->smallBuf = false;
    else if (resp_buftype == CIFS_SMALL_BUFFER)
        srch_inf->smallBuf = true;
    else
        cERROR(1, "illegal search buffer type");

    if (rsp->hdr.Status == STATUS_NO_MORE_FILES)
        srch_inf->endOfSearch = 1;
    else
        srch_inf->endOfSearch = 0;

    return rc;

qdir_exit:
    free_rsp_buf(resp_buftype, rsp);
    return rc;
}

static int
send_set_info(const unsigned int xid, struct cifs_tcon *tcon,
           u64 persistent_fid, u64 volatile_fid, u32 pid, int info_class,
           unsigned int num, void **data, unsigned int *size)
{
    struct smb2_set_info_req *req;
    struct smb2_set_info_rsp *rsp = NULL;
    struct kvec *iov;
    int rc = 0;
    int resp_buftype;
    unsigned int i;
    struct TCP_Server_Info *server;
    struct cifs_ses *ses = tcon->ses;

    if (ses && (ses->server))
        server = ses->server;
    else
        return -EIO;

    if (!num)
        return -EINVAL;

    iov = kmalloc(sizeof(struct kvec) * num, GFP_KERNEL);
    if (!iov)
        return -ENOMEM;

    rc = small_smb2_init(SMB2_SET_INFO, tcon, (void **) &req);
    if (rc) {
        kfree(iov);
        return rc;
    }

    req->hdr.ProcessId = cpu_to_le32(pid);

    req->InfoType = SMB2_O_INFO_FILE;
    req->FileInfoClass = info_class;
    req->PersistentFileId = persistent_fid;
    req->VolatileFileId = volatile_fid;

    /* 4 for RFC1001 length and 1 for Buffer */
    req->BufferOffset =
            cpu_to_le16(sizeof(struct smb2_set_info_req) - 1 - 4);
    req->BufferLength = cpu_to_le32(*size);

    inc_rfc1001_len(req, *size - 1 /* Buffer */);

    memcpy(req->Buffer, *data, *size);

    iov[0].iov_base = (char *)req;
    /* 4 for RFC1001 length */
    iov[0].iov_len = get_rfc1002_length(req) + 4;

    for (i = 1; i < num; i++) {
        inc_rfc1001_len(req, size[i]);
        le32_add_cpu(&req->BufferLength, size[i]);
        iov[i].iov_base = (char *)data[i];
        iov[i].iov_len = size[i];
    }

    rc = SendReceive2(xid, ses, iov, num, &resp_buftype, 0);
    rsp = (struct smb2_set_info_rsp *)iov[0].iov_base;

    if (rc != 0) {
        cifs_stats_fail_inc(tcon, SMB2_SET_INFO_HE);
        goto out;
    }
out:
    free_rsp_buf(resp_buftype, rsp);
    kfree(iov);
    return rc;
}

int
SMB2_rename(const unsigned int xid, struct cifs_tcon *tcon,
        u64 persistent_fid, u64 volatile_fid, __le16 *target_file)
{
    struct smb2_file_rename_info info;
    void **data;
    unsigned int size[2];
    int rc;
    int len = (2 * UniStrnlen((wchar_t *)target_file, PATH_MAX));

    data = kmalloc(sizeof(void *) * 2, GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    info.ReplaceIfExists = 1; /* 1 = replace existing target with new */
                  /* 0 = fail if target already exists */
    info.RootDirectory = 0;  /* MBZ for network ops (why does spec say?) */
    info.FileNameLength = cpu_to_le32(len);

    data[0] = &info;
    size[0] = sizeof(struct smb2_file_rename_info);

    data[1] = target_file;
    size[1] = len + 2 /* null */;

    rc = send_set_info(xid, tcon, persistent_fid, volatile_fid,
               current->tgid, FILE_RENAME_INFORMATION, 2, data,
               size);
    kfree(data);
    return rc;
}

int
SMB2_set_hardlink(const unsigned int xid, struct cifs_tcon *tcon,
          u64 persistent_fid, u64 volatile_fid, __le16 *target_file)
{
    struct smb2_file_link_info info;
    void **data;
    unsigned int size[2];
    int rc;
    int len = (2 * UniStrnlen((wchar_t *)target_file, PATH_MAX));

    data = kmalloc(sizeof(void *) * 2, GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    info.ReplaceIfExists = 0; /* 1 = replace existing link with new */
                  /* 0 = fail if link already exists */
    info.RootDirectory = 0;  /* MBZ for network ops (why does spec say?) */
    info.FileNameLength = cpu_to_le32(len);

    data[0] = &info;
    size[0] = sizeof(struct smb2_file_link_info);

    data[1] = target_file;
    size[1] = len + 2 /* null */;

    rc = send_set_info(xid, tcon, persistent_fid, volatile_fid,
               current->tgid, FILE_LINK_INFORMATION, 2, data, size);
    kfree(data);
    return rc;
}

int
SMB2_set_eof(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
         u64 volatile_fid, u32 pid, __le64 *eof)
{
    struct smb2_file_eof_info info;
    void *data;
    unsigned int size;

    info.EndOfFile = *eof;

    data = &info;
    size = sizeof(struct smb2_file_eof_info);

    return send_set_info(xid, tcon, persistent_fid, volatile_fid, pid,
                 FILE_END_OF_FILE_INFORMATION, 1, &data, &size);
}

int
SMB2_set_info(const unsigned int xid, struct cifs_tcon *tcon,
          u64 persistent_fid, u64 volatile_fid, FILE_BASIC_INFO *buf)
{
    unsigned int size;
    size = sizeof(FILE_BASIC_INFO);
    return send_set_info(xid, tcon, persistent_fid, volatile_fid,
                 current->tgid, FILE_BASIC_INFORMATION, 1,
                 (void **)&buf, &size);
}

int
SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
          const u64 persistent_fid, const u64 volatile_fid,
          __u8 oplock_level)
{
    int rc;
    struct smb2_oplock_break *req = NULL;

    cFYI(1, "SMB2_oplock_break");
    rc = small_smb2_init(SMB2_OPLOCK_BREAK, tcon, (void **) &req);

    if (rc)
        return rc;

    req->VolatileFid = volatile_fid;
    req->PersistentFid = persistent_fid;
    req->OplockLevel = oplock_level;
    req->hdr.CreditRequest = cpu_to_le16(1);

    rc = SendReceiveNoRsp(xid, tcon->ses, (char *) req, CIFS_OBREAK_OP);
    /* SMB2 buffer freed by function above */

    if (rc) {
        cifs_stats_fail_inc(tcon, SMB2_OPLOCK_BREAK_HE);
        cFYI(1, "Send error in Oplock Break = %d", rc);
    }

    return rc;
}

static void
copy_fs_info_to_kstatfs(struct smb2_fs_full_size_info *pfs_inf,
            struct kstatfs *kst)
{
    kst->f_bsize = le32_to_cpu(pfs_inf->BytesPerSector) *
              le32_to_cpu(pfs_inf->SectorsPerAllocationUnit);
    kst->f_blocks = le64_to_cpu(pfs_inf->TotalAllocationUnits);
    kst->f_bfree  = le64_to_cpu(pfs_inf->ActualAvailableAllocationUnits);
    kst->f_bavail = le64_to_cpu(pfs_inf->CallerAvailableAllocationUnits);
    return;
}

static int
build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
           int outbuf_len, u64 persistent_fid, u64 volatile_fid)
{
    int rc;
    struct smb2_query_info_req *req;

    cFYI(1, "Query FSInfo level %d", level);

    if ((tcon->ses == NULL) || (tcon->ses->server == NULL))
        return -EIO;

    rc = small_smb2_init(SMB2_QUERY_INFO, tcon, (void **) &req);
    if (rc)
        return rc;

    req->InfoType = SMB2_O_INFO_FILESYSTEM;
    req->FileInfoClass = level;
    req->PersistentFileId = persistent_fid;
    req->VolatileFileId = volatile_fid;
    /* 4 for rfc1002 length field and 1 for pad */
    req->InputBufferOffset =
            cpu_to_le16(sizeof(struct smb2_query_info_req) - 1 - 4);
    req->OutputBufferLength = cpu_to_le32(
        outbuf_len + sizeof(struct smb2_query_info_rsp) - 1 - 4);

    iov->iov_base = (char *)req;
    /* 4 for rfc1002 length field */
    iov->iov_len = get_rfc1002_length(req) + 4;
    return 0;
}

int
SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,
          u64 persistent_fid, u64 volatile_fid, struct kstatfs *fsdata)
{
    struct smb2_query_info_rsp *rsp = NULL;
    struct kvec iov;
    int rc = 0;
    int resp_buftype;
    struct cifs_ses *ses = tcon->ses;
    struct smb2_fs_full_size_info *info = NULL;

    rc = build_qfs_info_req(&iov, tcon, FS_FULL_SIZE_INFORMATION,
                sizeof(struct smb2_fs_full_size_info),
                persistent_fid, volatile_fid);
    if (rc)
        return rc;

    rc = SendReceive2(xid, ses, &iov, 1, &resp_buftype, 0);
    if (rc) {
        cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
        goto qinf_exit;
    }
    rsp = (struct smb2_query_info_rsp *)iov.iov_base;

    info = (struct smb2_fs_full_size_info *)(4 /* RFC1001 len */ +
        le16_to_cpu(rsp->OutputBufferOffset) + (char *)&rsp->hdr);
    rc = validate_buf(le16_to_cpu(rsp->OutputBufferOffset),
              le32_to_cpu(rsp->OutputBufferLength), &rsp->hdr,
              sizeof(struct smb2_fs_full_size_info));
    if (!rc)
        copy_fs_info_to_kstatfs(info, fsdata);

qinf_exit:
    free_rsp_buf(resp_buftype, iov.iov_base);
    return rc;
}

int
smb2_lockv(const unsigned int xid, struct cifs_tcon *tcon,
       const __u64 persist_fid, const __u64 volatile_fid, const __u32 pid,
       const __u32 num_lock, struct smb2_lock_element *buf)
{
    int rc = 0;
    struct smb2_lock_req *req = NULL;
    struct kvec iov[2];
    int resp_buf_type;
    unsigned int count;

    cFYI(1, "smb2_lockv num lock %d", num_lock);

    rc = small_smb2_init(SMB2_LOCK, tcon, (void **) &req);
    if (rc)
        return rc;

    req->hdr.ProcessId = cpu_to_le32(pid);
    req->LockCount = cpu_to_le16(num_lock);

    req->PersistentFileId = persist_fid;
    req->VolatileFileId = volatile_fid;

    count = num_lock * sizeof(struct smb2_lock_element);
    inc_rfc1001_len(req, count - sizeof(struct smb2_lock_element));

    iov[0].iov_base = (char *)req;
    /* 4 for rfc1002 length field and count for all locks */
    iov[0].iov_len = get_rfc1002_length(req) + 4 - count;
    iov[1].iov_base = (char *)buf;
    iov[1].iov_len = count;

    cifs_stats_inc(&tcon->stats.cifs_stats.num_locks);
    rc = SendReceive2(xid, tcon->ses, iov, 2, &resp_buf_type, CIFS_NO_RESP);
    if (rc) {
        cFYI(1, "Send error in smb2_lockv = %d", rc);
        cifs_stats_fail_inc(tcon, SMB2_LOCK_HE);
    }

    return rc;
}

int
SMB2_lock(const unsigned int xid, struct cifs_tcon *tcon,
      const __u64 persist_fid, const __u64 volatile_fid, const __u32 pid,
      const __u64 length, const __u64 offset, const __u32 lock_flags,
      const bool wait)
{
    struct smb2_lock_element lock;

    lock.Offset = cpu_to_le64(offset);
    lock.Length = cpu_to_le64(length);
    lock.Flags = cpu_to_le32(lock_flags);
    if (!wait && lock_flags != SMB2_LOCKFLAG_UNLOCK)
        lock.Flags |= cpu_to_le32(SMB2_LOCKFLAG_FAIL_IMMEDIATELY);

    return smb2_lockv(xid, tcon, persist_fid, volatile_fid, pid, 1, &lock);
}

int
SMB2_lease_break(const unsigned int xid, struct cifs_tcon *tcon,
         __u8 *lease_key, const __le32 lease_state)
{
    int rc;
    struct smb2_lease_ack *req = NULL;

    cFYI(1, "SMB2_lease_break");
    rc = small_smb2_init(SMB2_OPLOCK_BREAK, tcon, (void **) &req);

    if (rc)
        return rc;

    req->hdr.CreditRequest = cpu_to_le16(1);
    req->StructureSize = cpu_to_le16(36);
    inc_rfc1001_len(req, 12);

    memcpy(req->LeaseKey, lease_key, 16);
    req->LeaseState = lease_state;

    rc = SendReceiveNoRsp(xid, tcon->ses, (char *) req, CIFS_OBREAK_OP);
    /* SMB2 buffer freed by function above */

    if (rc) {
        cifs_stats_fail_inc(tcon, SMB2_OPLOCK_BREAK_HE);
        cFYI(1, "Send error in Lease Break = %d", rc);
    }

    return rc;
}