Merge tag 'soc-fixes-6.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

[people/ms/linux.git] / fs / cifs / smb2pdu.c

// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   Copyright (C) International Business Machines  Corp., 2009, 2013
 *                 Etersoft, 2012
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *              Pavel Shilovsky (pshilovsky@samba.org) 2012
 *
 *   Contains the routines for constructing the SMB2 PDUs themselves
 *
 */

 /* 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/uuid.h>
#include <linux/pagemap.h>
#include <linux/xattr.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"
#include "cifs_spnego.h"
#include "smbdirect.h"
#include "trace.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif
#include "cached_dir.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 */
};

int smb3_encryption_required(const struct cifs_tcon *tcon)
{
        if (!tcon || !tcon->ses)
                return 0;
        if ((tcon->ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA) ||
            (tcon->share_flags & SHI1005_FLAGS_ENCRYPT_DATA))
                return 1;
        if (tcon->seal &&
            (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
                return 1;
        return 0;
}

static void
smb2_hdr_assemble(struct smb2_hdr *shdr, __le16 smb2_cmd,
                  const struct cifs_tcon *tcon,
                  struct TCP_Server_Info *server)
{
        shdr->ProtocolId = SMB2_PROTO_NUMBER;
        shdr->StructureSize = cpu_to_le16(64);
        shdr->Command = smb2_cmd;
        if (server) {
                spin_lock(&server->req_lock);
                /* Request up to 10 credits but don't go over the limit. */
                if (server->credits >= server->max_credits)
                        shdr->CreditRequest = cpu_to_le16(0);
                else
                        shdr->CreditRequest = cpu_to_le16(
                                min_t(int, server->max_credits -
                                                server->credits, 10));
                spin_unlock(&server->req_lock);
        } else {
                shdr->CreditRequest = cpu_to_le16(2);
        }
        shdr->Id.SyncId.ProcessId = cpu_to_le32((__u16)current->tgid);

        if (!tcon)
                goto out;

        /* GLOBAL_CAP_LARGE_MTU will only be set if dialect > SMB2.02 */
        /* See sections 2.2.4 and 3.2.4.1.5 of MS-SMB2 */
        if (server && (server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
                shdr->CreditCharge = cpu_to_le16(1);
        /* else CreditCharge MBZ */

        shdr->Id.SyncId.TreeId = cpu_to_le32(tcon->tid);
        /* Uid is not converted */
        if (tcon->ses)
                shdr->SessionId = cpu_to_le64(tcon->ses->Suid);

        /*
         * If we would set SMB2_FLAGS_DFS_OPERATIONS on open we also would have
         * to pass the path on the Open SMB prefixed by \\server\share.
         * Not sure when we would need to do the augmented path (if ever) and
         * setting this flag breaks the SMB2 open operation since it is
         * illegal to send an empty path name (without \\server\share prefix)
         * when the DFS flag is set in the SMB open header. We could
         * consider setting the flag on all operations other than open
         * but it is safer to net set it for now.
         */
/*      if (tcon->share_flags & SHI1005_FLAGS_DFS)
                shdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS; */

        if (server && server->sign && !smb3_encryption_required(tcon))
                shdr->Flags |= SMB2_FLAGS_SIGNED;
out:
        return;
}

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

        /*
         * 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 0;

        /*
         * Need to also skip SMB2_IOCTL because it is used for checking nested dfs links in
         * cifs_tree_connect().
         */
        if (smb2_command == SMB2_TREE_CONNECT || smb2_command == SMB2_IOCTL)
                return 0;

        spin_lock(&tcon->tc_lock);
        if (tcon->status == TID_EXITING) {
                /*
                 * 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)) {
                        spin_unlock(&tcon->tc_lock);
                        cifs_dbg(FYI, "can not send cmd %d while umounting\n",
                                 smb2_command);
                        return -ENODEV;
                }
        }
        spin_unlock(&tcon->tc_lock);
        if ((!tcon->ses) || (tcon->ses->ses_status == SES_EXITING) ||
            (!tcon->ses->server) || !server)
                return -EIO;

        ses = tcon->ses;
        retries = server->nr_targets;

        /*
         * Give demultiplex thread up to 10 seconds to each target available for
         * 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;
                }

                rc = wait_event_interruptible_timeout(server->response_q,
                                                      (server->tcpStatus != CifsNeedReconnect),
                                                      10 * HZ);
                if (rc < 0) {
                        cifs_dbg(FYI, "%s: aborting reconnect due to a received signal by the process\n",
                                 __func__);
                        return -ERESTARTSYS;
                }

                /* are we still trying to reconnect? */
                spin_lock(&server->srv_lock);
                if (server->tcpStatus != CifsNeedReconnect) {
                        spin_unlock(&server->srv_lock);
                        break;
                }
                spin_unlock(&server->srv_lock);

                if (retries && --retries)
                        continue;

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

        spin_lock(&ses->chan_lock);
        if (!cifs_chan_needs_reconnect(ses, server) && !tcon->need_reconnect) {
                spin_unlock(&ses->chan_lock);
                return 0;
        }
        spin_unlock(&ses->chan_lock);
        cifs_dbg(FYI, "sess reconnect mask: 0x%lx, tcon reconnect: %d",
                 tcon->ses->chans_need_reconnect,
                 tcon->need_reconnect);

        nls_codepage = load_nls_default();

        /*
         * Recheck after acquire mutex. If another thread is negotiating
         * and the server never sends an answer the socket will be closed
         * and tcpStatus set to reconnect.
         */
        spin_lock(&server->srv_lock);
        if (server->tcpStatus == CifsNeedReconnect) {
                spin_unlock(&server->srv_lock);
                rc = -EHOSTDOWN;
                goto out;
        }
        spin_unlock(&server->srv_lock);

        /*
         * need to prevent multiple threads trying to simultaneously
         * reconnect the same SMB session
         */
        spin_lock(&ses->chan_lock);
        if (!cifs_chan_needs_reconnect(ses, server)) {
                spin_unlock(&ses->chan_lock);

                /* this means that we only need to tree connect */
                if (tcon->need_reconnect)
                        goto skip_sess_setup;

                goto out;
        }
        spin_unlock(&ses->chan_lock);

        mutex_lock(&ses->session_mutex);
        rc = cifs_negotiate_protocol(0, ses, server);
        if (!rc) {
                rc = cifs_setup_session(0, ses, server, nls_codepage);
                if ((rc == -EACCES) && !tcon->retry) {
                        mutex_unlock(&ses->session_mutex);
                        rc = -EHOSTDOWN;
                        goto failed;
                } else if (rc) {
                        mutex_unlock(&ses->session_mutex);
                        goto out;
                }
        } else {
                mutex_unlock(&ses->session_mutex);
                goto out;
        }
        mutex_unlock(&ses->session_mutex);

skip_sess_setup:
        mutex_lock(&ses->session_mutex);
        if (!tcon->need_reconnect) {
                mutex_unlock(&ses->session_mutex);
                goto out;
        }
        cifs_mark_open_files_invalid(tcon);
        if (tcon->use_persistent)
                tcon->need_reopen_files = true;

        rc = cifs_tree_connect(0, tcon, nls_codepage);
        mutex_unlock(&ses->session_mutex);

        cifs_dbg(FYI, "reconnect tcon rc = %d\n", rc);
        if (rc) {
                /* If sess reconnected but tcon didn't, something strange ... */
                pr_warn_once("reconnect tcon failed rc = %d\n", rc);
                goto out;
        }

        if (smb2_command != SMB2_INTERNAL_CMD)
                mod_delayed_work(cifsiod_wq, &server->reconnect, 0);

        atomic_inc(&tconInfoReconnectCount);
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:
                rc = -EAGAIN;
        }
failed:
        unload_nls(nls_codepage);
        return rc;
}

static void
fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon,
               struct TCP_Server_Info *server,
               void *buf,
               unsigned int *total_len)
{
        struct smb2_pdu *spdu = buf;
        /* lookup word count ie StructureSize from table */
        __u16 parmsize = smb2_req_struct_sizes[le16_to_cpu(smb2_command)];

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

        smb2_hdr_assemble(&spdu->hdr, smb2_command, tcon, server);
        spdu->StructureSize2 = cpu_to_le16(parmsize);

        *total_len = parmsize + sizeof(struct smb2_hdr);
}

/*
 * 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 __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
                                 struct TCP_Server_Info *server,
                                 void **request_buf, unsigned int *total_len)
{
        /* BB eventually switch this to SMB2 specific small buf size */
        if (smb2_command == SMB2_SET_INFO)
                *request_buf = cifs_buf_get();
        else
                *request_buf = cifs_small_buf_get();
        if (*request_buf == NULL) {
                /* BB should we add a retry in here if not a writepage? */
                return -ENOMEM;
        }

        fill_small_buf(smb2_command, tcon, server,
                       (struct smb2_hdr *)(*request_buf),
                       total_len);

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

        return 0;
}

static int smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
                               struct TCP_Server_Info *server,
                               void **request_buf, unsigned int *total_len)
{
        int rc;

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

        return __smb2_plain_req_init(smb2_command, tcon, server, request_buf,
                                     total_len);
}

static int smb2_ioctl_req_init(u32 opcode, struct cifs_tcon *tcon,
                               struct TCP_Server_Info *server,
                               void **request_buf, unsigned int *total_len)
{
        /* Skip reconnect only for FSCTL_VALIDATE_NEGOTIATE_INFO IOCTLs */
        if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO) {
                return __smb2_plain_req_init(SMB2_IOCTL, tcon, server,
                                             request_buf, total_len);
        }
        return smb2_plain_req_init(SMB2_IOCTL, tcon, server,
                                   request_buf, total_len);
}

/* For explanation of negotiate contexts see MS-SMB2 section 2.2.3.1 */

static void
build_preauth_ctxt(struct smb2_preauth_neg_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_PREAUTH_INTEGRITY_CAPABILITIES;
        pneg_ctxt->DataLength = cpu_to_le16(38);
        pneg_ctxt->HashAlgorithmCount = cpu_to_le16(1);
        pneg_ctxt->SaltLength = cpu_to_le16(SMB311_SALT_SIZE);
        get_random_bytes(pneg_ctxt->Salt, SMB311_SALT_SIZE);
        pneg_ctxt->HashAlgorithms = SMB2_PREAUTH_INTEGRITY_SHA512;
}

static void
build_compression_ctxt(struct smb2_compression_capabilities_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_COMPRESSION_CAPABILITIES;
        pneg_ctxt->DataLength =
                cpu_to_le16(sizeof(struct smb2_compression_capabilities_context)
                          - sizeof(struct smb2_neg_context));
        pneg_ctxt->CompressionAlgorithmCount = cpu_to_le16(3);
        pneg_ctxt->CompressionAlgorithms[0] = SMB3_COMPRESS_LZ77;
        pneg_ctxt->CompressionAlgorithms[1] = SMB3_COMPRESS_LZ77_HUFF;
        pneg_ctxt->CompressionAlgorithms[2] = SMB3_COMPRESS_LZNT1;
}

static unsigned int
build_signing_ctxt(struct smb2_signing_capabilities *pneg_ctxt)
{
        unsigned int ctxt_len = sizeof(struct smb2_signing_capabilities);
        unsigned short num_algs = 1; /* number of signing algorithms sent */

        pneg_ctxt->ContextType = SMB2_SIGNING_CAPABILITIES;
        /*
         * Context Data length must be rounded to multiple of 8 for some servers
         */
        pneg_ctxt->DataLength = cpu_to_le16(DIV_ROUND_UP(
                                sizeof(struct smb2_signing_capabilities) -
                                sizeof(struct smb2_neg_context) +
                                (num_algs * 2 /* sizeof u16 */), 8) * 8);
        pneg_ctxt->SigningAlgorithmCount = cpu_to_le16(num_algs);
        pneg_ctxt->SigningAlgorithms[0] = cpu_to_le16(SIGNING_ALG_AES_CMAC);

        ctxt_len += 2 /* sizeof le16 */ * num_algs;
        ctxt_len = DIV_ROUND_UP(ctxt_len, 8) * 8;
        return ctxt_len;
        /* TBD add SIGNING_ALG_AES_GMAC and/or SIGNING_ALG_HMAC_SHA256 */
}

static void
build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_ENCRYPTION_CAPABILITIES;
        if (require_gcm_256) {
                pneg_ctxt->DataLength = cpu_to_le16(4); /* Cipher Count + 1 cipher */
                pneg_ctxt->CipherCount = cpu_to_le16(1);
                pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES256_GCM;
        } else if (enable_gcm_256) {
                pneg_ctxt->DataLength = cpu_to_le16(8); /* Cipher Count + 3 ciphers */
                pneg_ctxt->CipherCount = cpu_to_le16(3);
                pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM;
                pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES256_GCM;
                pneg_ctxt->Ciphers[2] = SMB2_ENCRYPTION_AES128_CCM;
        } else {
                pneg_ctxt->DataLength = cpu_to_le16(6); /* Cipher Count + 2 ciphers */
                pneg_ctxt->CipherCount = cpu_to_le16(2);
                pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM;
                pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES128_CCM;
        }
}

static unsigned int
build_netname_ctxt(struct smb2_netname_neg_context *pneg_ctxt, char *hostname)
{
        struct nls_table *cp = load_nls_default();

        pneg_ctxt->ContextType = SMB2_NETNAME_NEGOTIATE_CONTEXT_ID;

        /* copy up to max of first 100 bytes of server name to NetName field */
        pneg_ctxt->DataLength = cpu_to_le16(2 * cifs_strtoUTF16(pneg_ctxt->NetName, hostname, 100, cp));
        /* context size is DataLength + minimal smb2_neg_context */
        return DIV_ROUND_UP(le16_to_cpu(pneg_ctxt->DataLength) +
                        sizeof(struct smb2_neg_context), 8) * 8;
}

static void
build_posix_ctxt(struct smb2_posix_neg_context *pneg_ctxt)
{
        pneg_ctxt->ContextType = SMB2_POSIX_EXTENSIONS_AVAILABLE;
        pneg_ctxt->DataLength = cpu_to_le16(POSIX_CTXT_DATA_LEN);
        /* SMB2_CREATE_TAG_POSIX is "0x93AD25509CB411E7B42383DE968BCD7C" */
        pneg_ctxt->Name[0] = 0x93;
        pneg_ctxt->Name[1] = 0xAD;
        pneg_ctxt->Name[2] = 0x25;
        pneg_ctxt->Name[3] = 0x50;
        pneg_ctxt->Name[4] = 0x9C;
        pneg_ctxt->Name[5] = 0xB4;
        pneg_ctxt->Name[6] = 0x11;
        pneg_ctxt->Name[7] = 0xE7;
        pneg_ctxt->Name[8] = 0xB4;
        pneg_ctxt->Name[9] = 0x23;
        pneg_ctxt->Name[10] = 0x83;
        pneg_ctxt->Name[11] = 0xDE;
        pneg_ctxt->Name[12] = 0x96;
        pneg_ctxt->Name[13] = 0x8B;
        pneg_ctxt->Name[14] = 0xCD;
        pneg_ctxt->Name[15] = 0x7C;
}

static void
assemble_neg_contexts(struct smb2_negotiate_req *req,
                      struct TCP_Server_Info *server, unsigned int *total_len)
{
        char *pneg_ctxt;
        char *hostname = NULL;
        unsigned int ctxt_len, neg_context_count;

        if (*total_len > 200) {
                /* In case length corrupted don't want to overrun smb buffer */
                cifs_server_dbg(VFS, "Bad frame length assembling neg contexts\n");
                return;
        }

        /*
         * round up total_len of fixed part of SMB3 negotiate request to 8
         * byte boundary before adding negotiate contexts
         */
        *total_len = roundup(*total_len, 8);

        pneg_ctxt = (*total_len) + (char *)req;
        req->NegotiateContextOffset = cpu_to_le32(*total_len);

        build_preauth_ctxt((struct smb2_preauth_neg_context *)pneg_ctxt);
        ctxt_len = DIV_ROUND_UP(sizeof(struct smb2_preauth_neg_context), 8) * 8;
        *total_len += ctxt_len;
        pneg_ctxt += ctxt_len;

        build_encrypt_ctxt((struct smb2_encryption_neg_context *)pneg_ctxt);
        ctxt_len = DIV_ROUND_UP(sizeof(struct smb2_encryption_neg_context), 8) * 8;
        *total_len += ctxt_len;
        pneg_ctxt += ctxt_len;

        /*
         * secondary channels don't have the hostname field populated
         * use the hostname field in the primary channel instead
         */
        hostname = CIFS_SERVER_IS_CHAN(server) ?
                server->primary_server->hostname : server->hostname;
        if (hostname && (hostname[0] != 0)) {
                ctxt_len = build_netname_ctxt((struct smb2_netname_neg_context *)pneg_ctxt,
                                              hostname);
                *total_len += ctxt_len;
                pneg_ctxt += ctxt_len;
                neg_context_count = 3;
        } else
                neg_context_count = 2;

        build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt);
        *total_len += sizeof(struct smb2_posix_neg_context);
        pneg_ctxt += sizeof(struct smb2_posix_neg_context);
        neg_context_count++;

        if (server->compress_algorithm) {
                build_compression_ctxt((struct smb2_compression_capabilities_context *)
                                pneg_ctxt);
                ctxt_len = DIV_ROUND_UP(
                        sizeof(struct smb2_compression_capabilities_context),
                                8) * 8;
                *total_len += ctxt_len;
                pneg_ctxt += ctxt_len;
                neg_context_count++;
        }

        if (enable_negotiate_signing) {
                ctxt_len = build_signing_ctxt((struct smb2_signing_capabilities *)
                                pneg_ctxt);
                *total_len += ctxt_len;
                pneg_ctxt += ctxt_len;
                neg_context_count++;
        }

        /* check for and add transport_capabilities and signing capabilities */
        req->NegotiateContextCount = cpu_to_le16(neg_context_count);

}

static void decode_preauth_context(struct smb2_preauth_neg_context *ctxt)
{
        unsigned int len = le16_to_cpu(ctxt->DataLength);

        /* If invalid preauth context warn but use what we requested, SHA-512 */
        if (len < MIN_PREAUTH_CTXT_DATA_LEN) {
                pr_warn_once("server sent bad preauth context\n");
                return;
        } else if (len < MIN_PREAUTH_CTXT_DATA_LEN + le16_to_cpu(ctxt->SaltLength)) {
                pr_warn_once("server sent invalid SaltLength\n");
                return;
        }
        if (le16_to_cpu(ctxt->HashAlgorithmCount) != 1)
                pr_warn_once("Invalid SMB3 hash algorithm count\n");
        if (ctxt->HashAlgorithms != SMB2_PREAUTH_INTEGRITY_SHA512)
                pr_warn_once("unknown SMB3 hash algorithm\n");
}

static void decode_compress_ctx(struct TCP_Server_Info *server,
                         struct smb2_compression_capabilities_context *ctxt)
{
        unsigned int len = le16_to_cpu(ctxt->DataLength);

        /* sizeof compress context is a one element compression capbility struct */
        if (len < 10) {
                pr_warn_once("server sent bad compression cntxt\n");
                return;
        }
        if (le16_to_cpu(ctxt->CompressionAlgorithmCount) != 1) {
                pr_warn_once("Invalid SMB3 compress algorithm count\n");
                return;
        }
        if (le16_to_cpu(ctxt->CompressionAlgorithms[0]) > 3) {
                pr_warn_once("unknown compression algorithm\n");
                return;
        }
        server->compress_algorithm = ctxt->CompressionAlgorithms[0];
}

static int decode_encrypt_ctx(struct TCP_Server_Info *server,
                              struct smb2_encryption_neg_context *ctxt)
{
        unsigned int len = le16_to_cpu(ctxt->DataLength);

        cifs_dbg(FYI, "decode SMB3.11 encryption neg context of len %d\n", len);
        if (len < MIN_ENCRYPT_CTXT_DATA_LEN) {
                pr_warn_once("server sent bad crypto ctxt len\n");
                return -EINVAL;
        }

        if (le16_to_cpu(ctxt->CipherCount) != 1) {
                pr_warn_once("Invalid SMB3.11 cipher count\n");
                return -EINVAL;
        }
        cifs_dbg(FYI, "SMB311 cipher type:%d\n", le16_to_cpu(ctxt->Ciphers[0]));
        if (require_gcm_256) {
                if (ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES256_GCM) {
                        cifs_dbg(VFS, "Server does not support requested encryption type (AES256 GCM)\n");
                        return -EOPNOTSUPP;
                }
        } else if (ctxt->Ciphers[0] == 0) {
                /*
                 * e.g. if server only supported AES256_CCM (very unlikely)
                 * or server supported no encryption types or had all disabled.
                 * Since GLOBAL_CAP_ENCRYPTION will be not set, in the case
                 * in which mount requested encryption ("seal") checks later
                 * on during tree connection will return proper rc, but if
                 * seal not requested by client, since server is allowed to
                 * return 0 to indicate no supported cipher, we can't fail here
                 */
                server->cipher_type = 0;
                server->capabilities &= ~SMB2_GLOBAL_CAP_ENCRYPTION;
                pr_warn_once("Server does not support requested encryption types\n");
                return 0;
        } else if ((ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_CCM) &&
                   (ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES128_GCM) &&
                   (ctxt->Ciphers[0] != SMB2_ENCRYPTION_AES256_GCM)) {
                /* server returned a cipher we didn't ask for */
                pr_warn_once("Invalid SMB3.11 cipher returned\n");
                return -EINVAL;
        }
        server->cipher_type = ctxt->Ciphers[0];
        server->capabilities |= SMB2_GLOBAL_CAP_ENCRYPTION;
        return 0;
}

static void decode_signing_ctx(struct TCP_Server_Info *server,
                               struct smb2_signing_capabilities *pctxt)
{
        unsigned int len = le16_to_cpu(pctxt->DataLength);

        if ((len < 4) || (len > 16)) {
                pr_warn_once("server sent bad signing negcontext\n");
                return;
        }
        if (le16_to_cpu(pctxt->SigningAlgorithmCount) != 1) {
                pr_warn_once("Invalid signing algorithm count\n");
                return;
        }
        if (le16_to_cpu(pctxt->SigningAlgorithms[0]) > 2) {
                pr_warn_once("unknown signing algorithm\n");
                return;
        }

        server->signing_negotiated = true;
        server->signing_algorithm = le16_to_cpu(pctxt->SigningAlgorithms[0]);
        cifs_dbg(FYI, "signing algorithm %d chosen\n",
                     server->signing_algorithm);
}


static int smb311_decode_neg_context(struct smb2_negotiate_rsp *rsp,
                                     struct TCP_Server_Info *server,
                                     unsigned int len_of_smb)
{
        struct smb2_neg_context *pctx;
        unsigned int offset = le32_to_cpu(rsp->NegotiateContextOffset);
        unsigned int ctxt_cnt = le16_to_cpu(rsp->NegotiateContextCount);
        unsigned int len_of_ctxts, i;
        int rc = 0;

        cifs_dbg(FYI, "decoding %d negotiate contexts\n", ctxt_cnt);
        if (len_of_smb <= offset) {
                cifs_server_dbg(VFS, "Invalid response: negotiate context offset\n");
                return -EINVAL;
        }

        len_of_ctxts = len_of_smb - offset;

        for (i = 0; i < ctxt_cnt; i++) {
                int clen;
                /* check that offset is not beyond end of SMB */
                if (len_of_ctxts == 0)
                        break;

                if (len_of_ctxts < sizeof(struct smb2_neg_context))
                        break;

                pctx = (struct smb2_neg_context *)(offset + (char *)rsp);
                clen = le16_to_cpu(pctx->DataLength);
                if (clen > len_of_ctxts)
                        break;

                if (pctx->ContextType == SMB2_PREAUTH_INTEGRITY_CAPABILITIES)
                        decode_preauth_context(
                                (struct smb2_preauth_neg_context *)pctx);
                else if (pctx->ContextType == SMB2_ENCRYPTION_CAPABILITIES)
                        rc = decode_encrypt_ctx(server,
                                (struct smb2_encryption_neg_context *)pctx);
                else if (pctx->ContextType == SMB2_COMPRESSION_CAPABILITIES)
                        decode_compress_ctx(server,
                                (struct smb2_compression_capabilities_context *)pctx);
                else if (pctx->ContextType == SMB2_POSIX_EXTENSIONS_AVAILABLE)
                        server->posix_ext_supported = true;
                else if (pctx->ContextType == SMB2_SIGNING_CAPABILITIES)
                        decode_signing_ctx(server,
                                (struct smb2_signing_capabilities *)pctx);
                else
                        cifs_server_dbg(VFS, "unknown negcontext of type %d ignored\n",
                                le16_to_cpu(pctx->ContextType));

                if (rc)
                        break;
                /* offsets must be 8 byte aligned */
                clen = (clen + 7) & ~0x7;
                offset += clen + sizeof(struct smb2_neg_context);
                len_of_ctxts -= clen;
        }
        return rc;
}

static struct create_posix *
create_posix_buf(umode_t mode)
{
        struct create_posix *buf;

        buf = kzalloc(sizeof(struct create_posix),
                        GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset =
                cpu_to_le16(offsetof(struct create_posix, Mode));
        buf->ccontext.DataLength = cpu_to_le32(4);
        buf->ccontext.NameOffset =
                cpu_to_le16(offsetof(struct create_posix, Name));
        buf->ccontext.NameLength = cpu_to_le16(16);

        /* SMB2_CREATE_TAG_POSIX is "0x93AD25509CB411E7B42383DE968BCD7C" */
        buf->Name[0] = 0x93;
        buf->Name[1] = 0xAD;
        buf->Name[2] = 0x25;
        buf->Name[3] = 0x50;
        buf->Name[4] = 0x9C;
        buf->Name[5] = 0xB4;
        buf->Name[6] = 0x11;
        buf->Name[7] = 0xE7;
        buf->Name[8] = 0xB4;
        buf->Name[9] = 0x23;
        buf->Name[10] = 0x83;
        buf->Name[11] = 0xDE;
        buf->Name[12] = 0x96;
        buf->Name[13] = 0x8B;
        buf->Name[14] = 0xCD;
        buf->Name[15] = 0x7C;
        buf->Mode = cpu_to_le32(mode);
        cifs_dbg(FYI, "mode on posix create 0%o\n", mode);
        return buf;
}

static int
add_posix_context(struct kvec *iov, unsigned int *num_iovec, umode_t mode)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_posix_buf(mode);
        if (mode == ACL_NO_MODE)
                cifs_dbg(FYI, "Invalid mode\n");
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_posix);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_posix));
        *num_iovec = num + 1;
        return 0;
}


/*
 *
 *      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 TCP_Server_Info *server)
{
        struct smb_rqst rqst;
        struct smb2_negotiate_req *req;
        struct smb2_negotiate_rsp *rsp;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int rc = 0;
        int resp_buftype;
        int blob_offset, blob_length;
        char *security_blob;
        int flags = CIFS_NEG_OP;
        unsigned int total_len;

        cifs_dbg(FYI, "Negotiate protocol\n");

        if (!server) {
                WARN(1, "%s: server is NULL!\n", __func__);
                return -EIO;
        }

        rc = smb2_plain_req_init(SMB2_NEGOTIATE, NULL, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        req->hdr.SessionId = 0;

        memset(server->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);
        memset(ses->preauth_sha_hash, 0, SMB2_PREAUTH_HASH_SIZE);

        if (strcmp(server->vals->version_string,
                   SMB3ANY_VERSION_STRING) == 0) {
                req->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
                req->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
                req->Dialects[2] = cpu_to_le16(SMB311_PROT_ID);
                req->DialectCount = cpu_to_le16(3);
                total_len += 6;
        } else if (strcmp(server->vals->version_string,
                   SMBDEFAULT_VERSION_STRING) == 0) {
                req->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
                req->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
                req->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
                req->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
                req->DialectCount = cpu_to_le16(4);
                total_len += 8;
        } else {
                /* otherwise send specific dialect */
                req->Dialects[0] = cpu_to_le16(server->vals->protocol_id);
                req->DialectCount = cpu_to_le16(1);
                total_len += 2;
        }

        /* only one of SMB2 signing flags may be set in SMB2 request */
        if (ses->sign)
                req->SecurityMode = cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
        else if (global_secflags & CIFSSEC_MAY_SIGN)
                req->SecurityMode = cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
        else
                req->SecurityMode = 0;

        req->Capabilities = cpu_to_le32(server->vals->req_capabilities);
        if (ses->chan_max > 1)
                req->Capabilities |= cpu_to_le32(SMB2_GLOBAL_CAP_MULTI_CHANNEL);

        /* ClientGUID must be zero for SMB2.02 dialect */
        if (server->vals->protocol_id == SMB20_PROT_ID)
                memset(req->ClientGUID, 0, SMB2_CLIENT_GUID_SIZE);
        else {
                memcpy(req->ClientGUID, server->client_guid,
                        SMB2_CLIENT_GUID_SIZE);
                if ((server->vals->protocol_id == SMB311_PROT_ID) ||
                    (strcmp(server->vals->version_string,
                     SMB3ANY_VERSION_STRING) == 0) ||
                    (strcmp(server->vals->version_string,
                     SMBDEFAULT_VERSION_STRING) == 0))
                        assemble_neg_contexts(req, server, &total_len);
        }
        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        cifs_small_buf_release(req);
        rsp = (struct smb2_negotiate_rsp *)rsp_iov.iov_base;
        /*
         * No tcon so can't do
         * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
         */
        if (rc == -EOPNOTSUPP) {
                cifs_server_dbg(VFS, "Dialect not supported by server. Consider  specifying vers=1.0 or vers=2.0 on mount for accessing older servers\n");
                goto neg_exit;
        } else if (rc != 0)
                goto neg_exit;

        rc = -EIO;
        if (strcmp(server->vals->version_string,
                   SMB3ANY_VERSION_STRING) == 0) {
                if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
                        cifs_server_dbg(VFS,
                                "SMB2 dialect returned but not requested\n");
                        goto neg_exit;
                } else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
                        cifs_server_dbg(VFS,
                                "SMB2.1 dialect returned but not requested\n");
                        goto neg_exit;
                } else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
                        /* ops set to 3.0 by default for default so update */
                        server->ops = &smb311_operations;
                        server->vals = &smb311_values;
                }
        } else if (strcmp(server->vals->version_string,
                   SMBDEFAULT_VERSION_STRING) == 0) {
                if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID)) {
                        cifs_server_dbg(VFS,
                                "SMB2 dialect returned but not requested\n");
                        goto neg_exit;
                } else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID)) {
                        /* ops set to 3.0 by default for default so update */
                        server->ops = &smb21_operations;
                        server->vals = &smb21_values;
                } else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
                        server->ops = &smb311_operations;
                        server->vals = &smb311_values;
                }
        } else if (le16_to_cpu(rsp->DialectRevision) !=
                                server->vals->protocol_id) {
                /* if requested single dialect ensure returned dialect matched */
                cifs_server_dbg(VFS, "Invalid 0x%x dialect returned: not requested\n",
                                le16_to_cpu(rsp->DialectRevision));
                goto neg_exit;
        }

        cifs_dbg(FYI, "mode 0x%x\n", rsp->SecurityMode);

        if (rsp->DialectRevision == cpu_to_le16(SMB20_PROT_ID))
                cifs_dbg(FYI, "negotiated smb2.0 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB21_PROT_ID))
                cifs_dbg(FYI, "negotiated smb2.1 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB30_PROT_ID))
                cifs_dbg(FYI, "negotiated smb3.0 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB302_PROT_ID))
                cifs_dbg(FYI, "negotiated smb3.02 dialect\n");
        else if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID))
                cifs_dbg(FYI, "negotiated smb3.1.1 dialect\n");
        else {
                cifs_server_dbg(VFS, "Invalid dialect returned by server 0x%x\n",
                                le16_to_cpu(rsp->DialectRevision));
                goto neg_exit;
        }

        rc = 0;
        server->dialect = le16_to_cpu(rsp->DialectRevision);

        /*
         * Keep a copy of the hash after negprot. This hash will be
         * the starting hash value for all sessions made from this
         * server.
         */
        memcpy(server->preauth_sha_hash, ses->preauth_sha_hash,
               SMB2_PREAUTH_HASH_SIZE);

        /* SMB2 only has an extended negflavor */
        server->negflavor = CIFS_NEGFLAVOR_EXTENDED;
        /* set it to the maximum buffer size value we can send with 1 credit */
        server->maxBuf = min_t(unsigned int, le32_to_cpu(rsp->MaxTransactSize),
                               SMB2_MAX_BUFFER_SIZE);
        server->max_read = le32_to_cpu(rsp->MaxReadSize);
        server->max_write = le32_to_cpu(rsp->MaxWriteSize);
        server->sec_mode = le16_to_cpu(rsp->SecurityMode);
        if ((server->sec_mode & SMB2_SEC_MODE_FLAGS_ALL) != server->sec_mode)
                cifs_dbg(FYI, "Server returned unexpected security mode 0x%x\n",
                                server->sec_mode);
        server->capabilities = le32_to_cpu(rsp->Capabilities);
        /* Internal types */
        server->capabilities |= SMB2_NT_FIND | SMB2_LARGE_FILES;

        /*
         * SMB3.0 supports only 1 cipher and doesn't have a encryption neg context
         * Set the cipher type manually.
         */
        if (server->dialect == SMB30_PROT_ID && (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
                server->cipher_type = SMB2_ENCRYPTION_AES128_CCM;

        security_blob = smb2_get_data_area_len(&blob_offset, &blob_length,
                                               (struct smb2_hdr *)rsp);
        /*
         * See MS-SMB2 section 2.2.4: if no blob, client picks default which
         * for us will be
         *      ses->sectype = RawNTLMSSP;
         * but for time being this is our only auth choice so doesn't matter.
         * We just found a server which sets blob length to zero expecting raw.
         */
        if (blob_length == 0) {
                cifs_dbg(FYI, "missing security blob on negprot\n");
                server->sec_ntlmssp = true;
        }

        rc = cifs_enable_signing(server, ses->sign);
        if (rc)
                goto neg_exit;
        if (blob_length) {
                rc = decode_negTokenInit(security_blob, blob_length, server);
                if (rc == 1)
                        rc = 0;
                else if (rc == 0)
                        rc = -EIO;
        }

        if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
                if (rsp->NegotiateContextCount)
                        rc = smb311_decode_neg_context(rsp, server,
                                                       rsp_iov.iov_len);
                else
                        cifs_server_dbg(VFS, "Missing expected negotiate contexts\n");
        }
neg_exit:
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
{
        int rc;
        struct validate_negotiate_info_req *pneg_inbuf;
        struct validate_negotiate_info_rsp *pneg_rsp = NULL;
        u32 rsplen;
        u32 inbuflen; /* max of 4 dialects */
        struct TCP_Server_Info *server = tcon->ses->server;

        cifs_dbg(FYI, "validate negotiate\n");

        /* In SMB3.11 preauth integrity supersedes validate negotiate */
        if (server->dialect == SMB311_PROT_ID)
                return 0;

        /*
         * validation ioctl must be signed, so no point sending this if we
         * can not sign it (ie are not known user).  Even if signing is not
         * required (enabled but not negotiated), in those cases we selectively
         * sign just this, the first and only signed request on a connection.
         * Having validation of negotiate info  helps reduce attack vectors.
         */
        if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_GUEST)
                return 0; /* validation requires signing */

        if (tcon->ses->user_name == NULL) {
                cifs_dbg(FYI, "Can't validate negotiate: null user mount\n");
                return 0; /* validation requires signing */
        }

        if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
                cifs_tcon_dbg(VFS, "Unexpected null user (anonymous) auth flag sent by server\n");

        pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_NOFS);
        if (!pneg_inbuf)
                return -ENOMEM;

        pneg_inbuf->Capabilities =
                        cpu_to_le32(server->vals->req_capabilities);
        if (tcon->ses->chan_max > 1)
                pneg_inbuf->Capabilities |= cpu_to_le32(SMB2_GLOBAL_CAP_MULTI_CHANNEL);

        memcpy(pneg_inbuf->Guid, server->client_guid,
                                        SMB2_CLIENT_GUID_SIZE);

        if (tcon->ses->sign)
                pneg_inbuf->SecurityMode =
                        cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
        else if (global_secflags & CIFSSEC_MAY_SIGN)
                pneg_inbuf->SecurityMode =
                        cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
        else
                pneg_inbuf->SecurityMode = 0;


        if (strcmp(server->vals->version_string,
                SMB3ANY_VERSION_STRING) == 0) {
                pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
                pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
                pneg_inbuf->Dialects[2] = cpu_to_le16(SMB311_PROT_ID);
                pneg_inbuf->DialectCount = cpu_to_le16(3);
                /* SMB 2.1 not included so subtract one dialect from len */
                inbuflen = sizeof(*pneg_inbuf) -
                                (sizeof(pneg_inbuf->Dialects[0]));
        } else if (strcmp(server->vals->version_string,
                SMBDEFAULT_VERSION_STRING) == 0) {
                pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
                pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
                pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
                pneg_inbuf->Dialects[3] = cpu_to_le16(SMB311_PROT_ID);
                pneg_inbuf->DialectCount = cpu_to_le16(4);
                /* structure is big enough for 4 dialects */
                inbuflen = sizeof(*pneg_inbuf);
        } else {
                /* otherwise specific dialect was requested */
                pneg_inbuf->Dialects[0] =
                        cpu_to_le16(server->vals->protocol_id);
                pneg_inbuf->DialectCount = cpu_to_le16(1);
                /* structure is big enough for 3 dialects, sending only 1 */
                inbuflen = sizeof(*pneg_inbuf) -
                                sizeof(pneg_inbuf->Dialects[0]) * 2;
        }

        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                FSCTL_VALIDATE_NEGOTIATE_INFO,
                (char *)pneg_inbuf, inbuflen, CIFSMaxBufSize,
                (char **)&pneg_rsp, &rsplen);
        if (rc == -EOPNOTSUPP) {
                /*
                 * Old Windows versions or Netapp SMB server can return
                 * not supported error. Client should accept it.
                 */
                cifs_tcon_dbg(VFS, "Server does not support validate negotiate\n");
                rc = 0;
                goto out_free_inbuf;
        } else if (rc != 0) {
                cifs_tcon_dbg(VFS, "validate protocol negotiate failed: %d\n",
                              rc);
                rc = -EIO;
                goto out_free_inbuf;
        }

        rc = -EIO;
        if (rsplen != sizeof(*pneg_rsp)) {
                cifs_tcon_dbg(VFS, "Invalid protocol negotiate response size: %d\n",
                              rsplen);

                /* relax check since Mac returns max bufsize allowed on ioctl */
                if (rsplen > CIFSMaxBufSize || rsplen < sizeof(*pneg_rsp))
                        goto out_free_rsp;
        }

        /* check validate negotiate info response matches what we got earlier */
        if (pneg_rsp->Dialect != cpu_to_le16(server->dialect))
                goto vneg_out;

        if (pneg_rsp->SecurityMode != cpu_to_le16(server->sec_mode))
                goto vneg_out;

        /* do not validate server guid because not saved at negprot time yet */

        if ((le32_to_cpu(pneg_rsp->Capabilities) | SMB2_NT_FIND |
              SMB2_LARGE_FILES) != server->capabilities)
                goto vneg_out;

        /* validate negotiate successful */
        rc = 0;
        cifs_dbg(FYI, "validate negotiate info successful\n");
        goto out_free_rsp;

vneg_out:
        cifs_tcon_dbg(VFS, "protocol revalidation - security settings mismatch\n");
out_free_rsp:
        kfree(pneg_rsp);
out_free_inbuf:
        kfree(pneg_inbuf);
        return rc;
}

enum securityEnum
smb2_select_sectype(struct TCP_Server_Info *server, enum securityEnum requested)
{
        switch (requested) {
        case Kerberos:
        case RawNTLMSSP:
                return requested;
        case NTLMv2:
                return RawNTLMSSP;
        case Unspecified:
                if (server->sec_ntlmssp &&
                        (global_secflags & CIFSSEC_MAY_NTLMSSP))
                        return RawNTLMSSP;
                if ((server->sec_kerberos || server->sec_mskerberos) &&
                        (global_secflags & CIFSSEC_MAY_KRB5))
                        return Kerberos;
                fallthrough;
        default:
                return Unspecified;
        }
}

struct SMB2_sess_data {
        unsigned int xid;
        struct cifs_ses *ses;
        struct TCP_Server_Info *server;
        struct nls_table *nls_cp;
        void (*func)(struct SMB2_sess_data *);
        int result;
        u64 previous_session;

        /* we will send the SMB in three pieces:
         * a fixed length beginning part, an optional
         * SPNEGO blob (which can be zero length), and a
         * last part which will include the strings
         * and rest of bcc area. This allows us to avoid
         * a large buffer 17K allocation
         */
        int buf0_type;
        struct kvec iov[2];
};

static int
SMB2_sess_alloc_buffer(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct TCP_Server_Info *server = sess_data->server;
        struct smb2_sess_setup_req *req;
        unsigned int total_len;
        bool is_binding = false;

        rc = smb2_plain_req_init(SMB2_SESSION_SETUP, NULL, server,
                                 (void **) &req,
                                 &total_len);
        if (rc)
                return rc;

        spin_lock(&ses->chan_lock);
        is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
        spin_unlock(&ses->chan_lock);

        if (is_binding) {
                req->hdr.SessionId = cpu_to_le64(ses->Suid);
                req->hdr.Flags |= SMB2_FLAGS_SIGNED;
                req->PreviousSessionId = 0;
                req->Flags = SMB2_SESSION_REQ_FLAG_BINDING;
                cifs_dbg(FYI, "Binding to sess id: %llx\n", ses->Suid);
        } else {
                /* First session, not a reauthenticate */
                req->hdr.SessionId = 0;
                /*
                 * if reconnect, we need to send previous sess id
                 * otherwise it is 0
                 */
                req->PreviousSessionId = cpu_to_le64(sess_data->previous_session);
                req->Flags = 0; /* MBZ */
                cifs_dbg(FYI, "Fresh session. Previous: %llx\n",
                         sess_data->previous_session);
        }

        /* enough to enable echos and oplocks and one max size write */
        req->hdr.CreditRequest = cpu_to_le16(130);

        /* only one of SMB2 signing flags may be set in SMB2 request */
        if (server->sign)
                req->SecurityMode = SMB2_NEGOTIATE_SIGNING_REQUIRED;
        else if (global_secflags & CIFSSEC_MAY_SIGN) /* one flag unlike MUST_ */
                req->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED;
        else
                req->SecurityMode = 0;

#ifdef CONFIG_CIFS_DFS_UPCALL
        req->Capabilities = cpu_to_le32(SMB2_GLOBAL_CAP_DFS);
#else
        req->Capabilities = 0;
#endif /* DFS_UPCALL */

        req->Channel = 0; /* MBZ */

        sess_data->iov[0].iov_base = (char *)req;
        /* 1 for pad */
        sess_data->iov[0].iov_len = total_len - 1;
        /*
         * This variable will be used to clear the buffer
         * allocated above in case of any error in the calling function.
         */
        sess_data->buf0_type = CIFS_SMALL_BUFFER;

        return 0;
}

static void
SMB2_sess_free_buffer(struct SMB2_sess_data *sess_data)
{
        free_rsp_buf(sess_data->buf0_type, sess_data->iov[0].iov_base);
        sess_data->buf0_type = CIFS_NO_BUFFER;
}

static int
SMB2_sess_sendreceive(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct smb_rqst rqst;
        struct smb2_sess_setup_req *req = sess_data->iov[0].iov_base;
        struct kvec rsp_iov = { NULL, 0 };

        /* 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 */);
        req->SecurityBufferLength = cpu_to_le16(sess_data->iov[1].iov_len);

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = sess_data->iov;
        rqst.rq_nvec = 2;

        /* BB add code to build os and lm fields */
        rc = cifs_send_recv(sess_data->xid, sess_data->ses,
                            sess_data->server,
                            &rqst,
                            &sess_data->buf0_type,
                            CIFS_LOG_ERROR | CIFS_SESS_OP, &rsp_iov);
        cifs_small_buf_release(sess_data->iov[0].iov_base);
        memcpy(&sess_data->iov[0], &rsp_iov, sizeof(struct kvec));

        return rc;
}

static int
SMB2_sess_establish_session(struct SMB2_sess_data *sess_data)
{
        int rc = 0;
        struct cifs_ses *ses = sess_data->ses;
        struct TCP_Server_Info *server = sess_data->server;

        cifs_server_lock(server);
        if (server->ops->generate_signingkey) {
                rc = server->ops->generate_signingkey(ses, server);
                if (rc) {
                        cifs_dbg(FYI,
                                "SMB3 session key generation failed\n");
                        cifs_server_unlock(server);
                        return rc;
                }
        }
        if (!server->session_estab) {
                server->sequence_number = 0x2;
                server->session_estab = true;
        }
        cifs_server_unlock(server);

        cifs_dbg(FYI, "SMB2/3 session established successfully\n");
        return rc;
}

#ifdef CONFIG_CIFS_UPCALL
static void
SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct TCP_Server_Info *server = sess_data->server;
        struct cifs_spnego_msg *msg;
        struct key *spnego_key = NULL;
        struct smb2_sess_setup_rsp *rsp = NULL;
        bool is_binding = false;

        rc = SMB2_sess_alloc_buffer(sess_data);
        if (rc)
                goto out;

        spnego_key = cifs_get_spnego_key(ses, server);
        if (IS_ERR(spnego_key)) {
                rc = PTR_ERR(spnego_key);
                if (rc == -ENOKEY)
                        cifs_dbg(VFS, "Verify user has a krb5 ticket and keyutils is installed\n");
                spnego_key = NULL;
                goto out;
        }

        msg = spnego_key->payload.data[0];
        /*
         * check version field to make sure that cifs.upcall is
         * sending us a response in an expected form
         */
        if (msg->version != CIFS_SPNEGO_UPCALL_VERSION) {
                cifs_dbg(VFS, "bad cifs.upcall version. Expected %d got %d\n",
                         CIFS_SPNEGO_UPCALL_VERSION, msg->version);
                rc = -EKEYREJECTED;
                goto out_put_spnego_key;
        }

        spin_lock(&ses->chan_lock);
        is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
        spin_unlock(&ses->chan_lock);

        /* keep session key if binding */
        if (!is_binding) {
                ses->auth_key.response = kmemdup(msg->data, msg->sesskey_len,
                                                 GFP_KERNEL);
                if (!ses->auth_key.response) {
                        cifs_dbg(VFS, "Kerberos can't allocate (%u bytes) memory\n",
                                 msg->sesskey_len);
                        rc = -ENOMEM;
                        goto out_put_spnego_key;
                }
                ses->auth_key.len = msg->sesskey_len;
        }

        sess_data->iov[1].iov_base = msg->data + msg->sesskey_len;
        sess_data->iov[1].iov_len = msg->secblob_len;

        rc = SMB2_sess_sendreceive(sess_data);
        if (rc)
                goto out_put_spnego_key;

        rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;
        /* keep session id and flags if binding */
        if (!is_binding) {
                ses->Suid = le64_to_cpu(rsp->hdr.SessionId);
                ses->session_flags = le16_to_cpu(rsp->SessionFlags);
        }

        rc = SMB2_sess_establish_session(sess_data);
out_put_spnego_key:
        key_invalidate(spnego_key);
        key_put(spnego_key);
out:
        sess_data->result = rc;
        sess_data->func = NULL;
        SMB2_sess_free_buffer(sess_data);
}
#else
static void
SMB2_auth_kerberos(struct SMB2_sess_data *sess_data)
{
        cifs_dbg(VFS, "Kerberos negotiated but upcall support disabled!\n");
        sess_data->result = -EOPNOTSUPP;
        sess_data->func = NULL;
}
#endif

static void
SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data);

static void
SMB2_sess_auth_rawntlmssp_negotiate(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct TCP_Server_Info *server = sess_data->server;
        struct smb2_sess_setup_rsp *rsp = NULL;
        unsigned char *ntlmssp_blob = NULL;
        bool use_spnego = false; /* else use raw ntlmssp */
        u16 blob_length = 0;
        bool is_binding = false;

        /*
         * If memory allocation is successful, caller of this function
         * frees it.
         */
        ses->ntlmssp = kmalloc(sizeof(struct ntlmssp_auth), GFP_KERNEL);
        if (!ses->ntlmssp) {
                rc = -ENOMEM;
                goto out_err;
        }
        ses->ntlmssp->sesskey_per_smbsess = true;

        rc = SMB2_sess_alloc_buffer(sess_data);
        if (rc)
                goto out_err;

        rc = build_ntlmssp_smb3_negotiate_blob(&ntlmssp_blob,
                                          &blob_length, ses, server,
                                          sess_data->nls_cp);
        if (rc)
                goto out_err;

        if (use_spnego) {
                /* BB eventually need to add this */
                cifs_dbg(VFS, "spnego not supported for SMB2 yet\n");
                rc = -EOPNOTSUPP;
                goto out;
        }
        sess_data->iov[1].iov_base = ntlmssp_blob;
        sess_data->iov[1].iov_len = blob_length;

        rc = SMB2_sess_sendreceive(sess_data);
        rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;

        /* If true, rc here is expected and not an error */
        if (sess_data->buf0_type != CIFS_NO_BUFFER &&
                rsp->hdr.Status == STATUS_MORE_PROCESSING_REQUIRED)
                rc = 0;

        if (rc)
                goto out;

        if (offsetof(struct smb2_sess_setup_rsp, Buffer) !=
                        le16_to_cpu(rsp->SecurityBufferOffset)) {
                cifs_dbg(VFS, "Invalid security buffer offset %d\n",
                        le16_to_cpu(rsp->SecurityBufferOffset));
                rc = -EIO;
                goto out;
        }
        rc = decode_ntlmssp_challenge(rsp->Buffer,
                        le16_to_cpu(rsp->SecurityBufferLength), ses);
        if (rc)
                goto out;

        cifs_dbg(FYI, "rawntlmssp session setup challenge phase\n");

        spin_lock(&ses->chan_lock);
        is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
        spin_unlock(&ses->chan_lock);

        /* keep existing ses id and flags if binding */
        if (!is_binding) {
                ses->Suid = le64_to_cpu(rsp->hdr.SessionId);
                ses->session_flags = le16_to_cpu(rsp->SessionFlags);
        }

out:
        kfree(ntlmssp_blob);
        SMB2_sess_free_buffer(sess_data);
        if (!rc) {
                sess_data->result = 0;
                sess_data->func = SMB2_sess_auth_rawntlmssp_authenticate;
                return;
        }
out_err:
        kfree(ses->ntlmssp);
        ses->ntlmssp = NULL;
        sess_data->result = rc;
        sess_data->func = NULL;
}

static void
SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data)
{
        int rc;
        struct cifs_ses *ses = sess_data->ses;
        struct TCP_Server_Info *server = sess_data->server;
        struct smb2_sess_setup_req *req;
        struct smb2_sess_setup_rsp *rsp = NULL;
        unsigned char *ntlmssp_blob = NULL;
        bool use_spnego = false; /* else use raw ntlmssp */
        u16 blob_length = 0;
        bool is_binding = false;

        rc = SMB2_sess_alloc_buffer(sess_data);
        if (rc)
                goto out;

        req = (struct smb2_sess_setup_req *) sess_data->iov[0].iov_base;
        req->hdr.SessionId = cpu_to_le64(ses->Suid);

        rc = build_ntlmssp_auth_blob(&ntlmssp_blob, &blob_length,
                                     ses, server,
                                     sess_data->nls_cp);
        if (rc) {
                cifs_dbg(FYI, "build_ntlmssp_auth_blob failed %d\n", rc);
                goto out;
        }

        if (use_spnego) {
                /* BB eventually need to add this */
                cifs_dbg(VFS, "spnego not supported for SMB2 yet\n");
                rc = -EOPNOTSUPP;
                goto out;
        }
        sess_data->iov[1].iov_base = ntlmssp_blob;
        sess_data->iov[1].iov_len = blob_length;

        rc = SMB2_sess_sendreceive(sess_data);
        if (rc)
                goto out;

        rsp = (struct smb2_sess_setup_rsp *)sess_data->iov[0].iov_base;

        spin_lock(&ses->chan_lock);
        is_binding = !CIFS_ALL_CHANS_NEED_RECONNECT(ses);
        spin_unlock(&ses->chan_lock);

        /* keep existing ses id and flags if binding */
        if (!is_binding) {
                ses->Suid = le64_to_cpu(rsp->hdr.SessionId);
                ses->session_flags = le16_to_cpu(rsp->SessionFlags);
        }

        rc = SMB2_sess_establish_session(sess_data);
#ifdef CONFIG_CIFS_DEBUG_DUMP_KEYS
        if (ses->server->dialect < SMB30_PROT_ID) {
                cifs_dbg(VFS, "%s: dumping generated SMB2 session keys\n", __func__);
                /*
                 * The session id is opaque in terms of endianness, so we can't
                 * print it as a long long. we dump it as we got it on the wire
                 */
                cifs_dbg(VFS, "Session Id    %*ph\n", (int)sizeof(ses->Suid),
                         &ses->Suid);
                cifs_dbg(VFS, "Session Key   %*ph\n",
                         SMB2_NTLMV2_SESSKEY_SIZE, ses->auth_key.response);
                cifs_dbg(VFS, "Signing Key   %*ph\n",
                         SMB3_SIGN_KEY_SIZE, ses->auth_key.response);
        }
#endif
out:
        kfree(ntlmssp_blob);
        SMB2_sess_free_buffer(sess_data);
        kfree(ses->ntlmssp);
        ses->ntlmssp = NULL;
        sess_data->result = rc;
        sess_data->func = NULL;
}

static int
SMB2_select_sec(struct SMB2_sess_data *sess_data)
{
        int type;
        struct cifs_ses *ses = sess_data->ses;
        struct TCP_Server_Info *server = sess_data->server;

        type = smb2_select_sectype(server, ses->sectype);
        cifs_dbg(FYI, "sess setup type %d\n", type);
        if (type == Unspecified) {
                cifs_dbg(VFS, "Unable to select appropriate authentication method!\n");
                return -EINVAL;
        }

        switch (type) {
        case Kerberos:
                sess_data->func = SMB2_auth_kerberos;
                break;
        case RawNTLMSSP:
                sess_data->func = SMB2_sess_auth_rawntlmssp_negotiate;
                break;
        default:
                cifs_dbg(VFS, "secType %d not supported!\n", type);
                return -EOPNOTSUPP;
        }

        return 0;
}

int
SMB2_sess_setup(const unsigned int xid, struct cifs_ses *ses,
                struct TCP_Server_Info *server,
                const struct nls_table *nls_cp)
{
        int rc = 0;
        struct SMB2_sess_data *sess_data;

        cifs_dbg(FYI, "Session Setup\n");

        if (!server) {
                WARN(1, "%s: server is NULL!\n", __func__);
                return -EIO;
        }

        sess_data = kzalloc(sizeof(struct SMB2_sess_data), GFP_KERNEL);
        if (!sess_data)
                return -ENOMEM;

        sess_data->xid = xid;
        sess_data->ses = ses;
        sess_data->server = server;
        sess_data->buf0_type = CIFS_NO_BUFFER;
        sess_data->nls_cp = (struct nls_table *) nls_cp;
        sess_data->previous_session = ses->Suid;

        rc = SMB2_select_sec(sess_data);
        if (rc)
                goto out;

        /*
         * Initialize the session hash with the server one.
         */
        memcpy(ses->preauth_sha_hash, server->preauth_sha_hash,
               SMB2_PREAUTH_HASH_SIZE);

        while (sess_data->func)
                sess_data->func(sess_data);

        if ((ses->session_flags & SMB2_SESSION_FLAG_IS_GUEST) && (ses->sign))
                cifs_server_dbg(VFS, "signing requested but authenticated as guest\n");
        rc = sess_data->result;
out:
        kfree(sess_data);
        return rc;
}

int
SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
{
        struct smb_rqst rqst;
        struct smb2_logoff_req *req; /* response is also trivial struct */
        int rc = 0;
        struct TCP_Server_Info *server;
        int flags = 0;
        unsigned int total_len;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int resp_buf_type;

        cifs_dbg(FYI, "disconnect session %p\n", ses);

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

        /* no need to send SMB logoff if uid already closed due to reconnect */
        spin_lock(&ses->chan_lock);
        if (CIFS_ALL_CHANS_NEED_RECONNECT(ses)) {
                spin_unlock(&ses->chan_lock);
                goto smb2_session_already_dead;
        }
        spin_unlock(&ses->chan_lock);

        rc = smb2_plain_req_init(SMB2_LOGOFF, NULL, ses->server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

         /* since no tcon, smb2_init can not do this, so do here */
        req->hdr.SessionId = cpu_to_le64(ses->Suid);

        if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
                flags |= CIFS_TRANSFORM_REQ;
        else if (server->sign)
                req->hdr.Flags |= SMB2_FLAGS_SIGNED;

        flags |= CIFS_NO_RSP_BUF;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, ses->server,
                            &rqst, &resp_buf_type, flags, &rsp_iov);
        cifs_small_buf_release(req);
        /*
         * No tcon so can't do
         * cifs_stats_inc(&tcon->stats.smb2_stats.smb2_com_fail[SMB2...]);
         */

smb2_session_already_dead:
        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 */)

/* These are similar values to what Windows uses */
static inline void init_copy_chunk_defaults(struct cifs_tcon *tcon)
{
        tcon->max_chunks = 256;
        tcon->max_bytes_chunk = 1048576;
        tcon->max_bytes_copy = 16777216;
}

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

        /* always use master channel */
        server = ses->server;

        cifs_dbg(FYI, "TCON\n");

        if (!server || !tree)
                return -EIO;

        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;
        }

        /* SMB2 TREE_CONNECT request must be called with TreeId == 0 */
        tcon->tid = 0;
        atomic_set(&tcon->num_remote_opens, 0);
        rc = smb2_plain_req_init(SMB2_TREE_CONNECT, tcon, server,
                                 (void **) &req, &total_len);
        if (rc) {
                kfree(unc_path);
                return rc;
        }

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        iov[0].iov_base = (char *)req;
        /* 1 for pad */
        iov[0].iov_len = total_len - 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 */);
        req->PathLength = cpu_to_le16(unc_path_len - 2);
        iov[1].iov_base = unc_path;
        iov[1].iov_len = unc_path_len;

        /*
         * 3.11 tcon req must be signed if not encrypted. See MS-SMB2 3.2.4.1.1
         * unless it is guest or anonymous user. See MS-SMB2 3.2.5.3.1
         * (Samba servers don't always set the flag so also check if null user)
         */
        if ((server->dialect == SMB311_PROT_ID) &&
            !smb3_encryption_required(tcon) &&
            !(ses->session_flags &
                    (SMB2_SESSION_FLAG_IS_GUEST|SMB2_SESSION_FLAG_IS_NULL)) &&
            ((ses->user_name != NULL) || (ses->sectype == Kerberos)))
                req->hdr.Flags |= SMB2_FLAGS_SIGNED;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 2;

        /* Need 64 for max size write so ask for more in case not there yet */
        req->hdr.CreditRequest = cpu_to_le16(64);

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        cifs_small_buf_release(req);
        rsp = (struct smb2_tree_connect_rsp *)rsp_iov.iov_base;
        trace_smb3_tcon(xid, tcon->tid, ses->Suid, tree, rc);
        if ((rc != 0) || (rsp == NULL)) {
                cifs_stats_fail_inc(tcon, SMB2_TREE_CONNECT_HE);
                tcon->need_reconnect = true;
                goto tcon_error_exit;
        }

        switch (rsp->ShareType) {
        case SMB2_SHARE_TYPE_DISK:
                cifs_dbg(FYI, "connection to disk share\n");
                break;
        case SMB2_SHARE_TYPE_PIPE:
                tcon->pipe = true;
                cifs_dbg(FYI, "connection to pipe share\n");
                break;
        case SMB2_SHARE_TYPE_PRINT:
                tcon->print = true;
                cifs_dbg(FYI, "connection to printer\n");
                break;
        default:
                cifs_server_dbg(VFS, "unknown share type %d\n", rsp->ShareType);
                rc = -EOPNOTSUPP;
                goto tcon_error_exit;
        }

        tcon->share_flags = le32_to_cpu(rsp->ShareFlags);
        tcon->capabilities = rsp->Capabilities; /* we keep caps little endian */
        tcon->maximal_access = le32_to_cpu(rsp->MaximalAccess);
        tcon->tid = le32_to_cpu(rsp->hdr.Id.SyncId.TreeId);
        strscpy(tcon->treeName, tree, sizeof(tcon->treeName));

        if ((rsp->Capabilities & SMB2_SHARE_CAP_DFS) &&
            ((tcon->share_flags & SHI1005_FLAGS_DFS) == 0))
                cifs_tcon_dbg(VFS, "DFS capability contradicts DFS flag\n");

        if (tcon->seal &&
            !(server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION))
                cifs_tcon_dbg(VFS, "Encryption is requested but not supported\n");

        init_copy_chunk_defaults(tcon);
        if (server->ops->validate_negotiate)
                rc = server->ops->validate_negotiate(xid, tcon);
tcon_exit:

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

tcon_error_exit:
        if (rsp && rsp->hdr.Status == STATUS_BAD_NETWORK_NAME)
                cifs_tcon_dbg(VFS, "BAD_NETWORK_NAME: %s\n", tree);
        goto tcon_exit;
}

int
SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon)
{
        struct smb_rqst rqst;
        struct smb2_tree_disconnect_req *req; /* response is trivial */
        int rc = 0;
        struct cifs_ses *ses = tcon->ses;
        int flags = 0;
        unsigned int total_len;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int resp_buf_type;

        cifs_dbg(FYI, "Tree Disconnect\n");

        if (!ses || !(ses->server))
                return -EIO;

        spin_lock(&ses->chan_lock);
        if ((tcon->need_reconnect) ||
            (CIFS_ALL_CHANS_NEED_RECONNECT(tcon->ses))) {
                spin_unlock(&ses->chan_lock);
                return 0;
        }
        spin_unlock(&ses->chan_lock);

        invalidate_all_cached_dirs(tcon);

        rc = smb2_plain_req_init(SMB2_TREE_DISCONNECT, tcon, ses->server,
                                 (void **) &req,
                                 &total_len);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        flags |= CIFS_NO_RSP_BUF;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, ses->server,
                            &rqst, &resp_buf_type, flags, &rsp_iov);
        cifs_small_buf_release(req);
        if (rc)
                cifs_stats_fail_inc(tcon, SMB2_TREE_DISCONNECT_HE);

        return rc;
}


static struct create_durable *
create_durable_buf(void)
{
        struct create_durable *buf;

        buf = kzalloc(sizeof(struct create_durable), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_durable, Data));
        buf->ccontext.DataLength = cpu_to_le32(16);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_durable, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_DURABLE_HANDLE_REQUEST is "DHnQ" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = 'n';
        buf->Name[3] = 'Q';
        return buf;
}

static struct create_durable *
create_reconnect_durable_buf(struct cifs_fid *fid)
{
        struct create_durable *buf;

        buf = kzalloc(sizeof(struct create_durable), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_durable, Data));
        buf->ccontext.DataLength = cpu_to_le32(16);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_durable, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        buf->Data.Fid.PersistentFileId = fid->persistent_fid;
        buf->Data.Fid.VolatileFileId = fid->volatile_fid;
        /* SMB2_CREATE_DURABLE_HANDLE_RECONNECT is "DHnC" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = 'n';
        buf->Name[3] = 'C';
        return buf;
}

static void
parse_query_id_ctxt(struct create_context *cc, struct smb2_file_all_info *buf)
{
        struct create_on_disk_id *pdisk_id = (struct create_on_disk_id *)cc;

        cifs_dbg(FYI, "parse query id context 0x%llx 0x%llx\n",
                pdisk_id->DiskFileId, pdisk_id->VolumeId);
        buf->IndexNumber = pdisk_id->DiskFileId;
}

static void
parse_posix_ctxt(struct create_context *cc, struct smb2_file_all_info *info,
                 struct create_posix_rsp *posix)
{
        int sid_len;
        u8 *beg = (u8 *)cc + le16_to_cpu(cc->DataOffset);
        u8 *end = beg + le32_to_cpu(cc->DataLength);
        u8 *sid;

        memset(posix, 0, sizeof(*posix));

        posix->nlink = le32_to_cpu(*(__le32 *)(beg + 0));
        posix->reparse_tag = le32_to_cpu(*(__le32 *)(beg + 4));
        posix->mode = le32_to_cpu(*(__le32 *)(beg + 8));

        sid = beg + 12;
        sid_len = posix_info_sid_size(sid, end);
        if (sid_len < 0) {
                cifs_dbg(VFS, "bad owner sid in posix create response\n");
                return;
        }
        memcpy(&posix->owner, sid, sid_len);

        sid = sid + sid_len;
        sid_len = posix_info_sid_size(sid, end);
        if (sid_len < 0) {
                cifs_dbg(VFS, "bad group sid in posix create response\n");
                return;
        }
        memcpy(&posix->group, sid, sid_len);

        cifs_dbg(FYI, "nlink=%d mode=%o reparse_tag=%x\n",
                 posix->nlink, posix->mode, posix->reparse_tag);
}

void
smb2_parse_contexts(struct TCP_Server_Info *server,
                    struct smb2_create_rsp *rsp,
                    unsigned int *epoch, char *lease_key, __u8 *oplock,
                    struct smb2_file_all_info *buf,
                    struct create_posix_rsp *posix)
{
        char *data_offset;
        struct create_context *cc;
        unsigned int next;
        unsigned int remaining;
        char *name;
        static const char smb3_create_tag_posix[] = {
                0x93, 0xAD, 0x25, 0x50, 0x9C,
                0xB4, 0x11, 0xE7, 0xB4, 0x23, 0x83,
                0xDE, 0x96, 0x8B, 0xCD, 0x7C
        };

        *oplock = 0;
        data_offset = (char *)rsp + le32_to_cpu(rsp->CreateContextsOffset);
        remaining = le32_to_cpu(rsp->CreateContextsLength);
        cc = (struct create_context *)data_offset;

        /* Initialize inode number to 0 in case no valid data in qfid context */
        if (buf)
                buf->IndexNumber = 0;

        while (remaining >= sizeof(struct create_context)) {
                name = le16_to_cpu(cc->NameOffset) + (char *)cc;
                if (le16_to_cpu(cc->NameLength) == 4 &&
                    strncmp(name, SMB2_CREATE_REQUEST_LEASE, 4) == 0)
                        *oplock = server->ops->parse_lease_buf(cc, epoch,
                                                           lease_key);
                else if (buf && (le16_to_cpu(cc->NameLength) == 4) &&
                    strncmp(name, SMB2_CREATE_QUERY_ON_DISK_ID, 4) == 0)
                        parse_query_id_ctxt(cc, buf);
                else if ((le16_to_cpu(cc->NameLength) == 16)) {
                        if (posix &&
                            memcmp(name, smb3_create_tag_posix, 16) == 0)
                                parse_posix_ctxt(cc, buf, posix);
                }
                /* else {
                        cifs_dbg(FYI, "Context not matched with len %d\n",
                                le16_to_cpu(cc->NameLength));
                        cifs_dump_mem("Cctxt name: ", name, 4);
                } */

                next = le32_to_cpu(cc->Next);
                if (!next)
                        break;
                remaining -= next;
                cc = (struct create_context *)((char *)cc + next);
        }

        if (rsp->OplockLevel != SMB2_OPLOCK_LEVEL_LEASE)
                *oplock = rsp->OplockLevel;

        return;
}

static int
add_lease_context(struct TCP_Server_Info *server, struct kvec *iov,
                  unsigned int *num_iovec, u8 *lease_key, __u8 *oplock)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = server->ops->create_lease_buf(lease_key, *oplock);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = server->vals->create_lease_size;
        req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_LEASE;
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength,
                     server->vals->create_lease_size);
        *num_iovec = num + 1;
        return 0;
}

static struct create_durable_v2 *
create_durable_v2_buf(struct cifs_open_parms *oparms)
{
        struct cifs_fid *pfid = oparms->fid;
        struct create_durable_v2 *buf;

        buf = kzalloc(sizeof(struct create_durable_v2), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_durable_v2, dcontext));
        buf->ccontext.DataLength = cpu_to_le32(sizeof(struct durable_context_v2));
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_durable_v2, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);

        /*
         * NB: Handle timeout defaults to 0, which allows server to choose
         * (most servers default to 120 seconds) and most clients default to 0.
         * This can be overridden at mount ("handletimeout=") if the user wants
         * a different persistent (or resilient) handle timeout for all opens
         * opens on a particular SMB3 mount.
         */
        buf->dcontext.Timeout = cpu_to_le32(oparms->tcon->handle_timeout);
        buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
        generate_random_uuid(buf->dcontext.CreateGuid);
        memcpy(pfid->create_guid, buf->dcontext.CreateGuid, 16);

        /* SMB2_CREATE_DURABLE_HANDLE_REQUEST is "DH2Q" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = '2';
        buf->Name[3] = 'Q';
        return buf;
}

static struct create_durable_handle_reconnect_v2 *
create_reconnect_durable_v2_buf(struct cifs_fid *fid)
{
        struct create_durable_handle_reconnect_v2 *buf;

        buf = kzalloc(sizeof(struct create_durable_handle_reconnect_v2),
                        GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset =
                cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
                                     dcontext));
        buf->ccontext.DataLength =
                cpu_to_le32(sizeof(struct durable_reconnect_context_v2));
        buf->ccontext.NameOffset =
                cpu_to_le16(offsetof(struct create_durable_handle_reconnect_v2,
                            Name));
        buf->ccontext.NameLength = cpu_to_le16(4);

        buf->dcontext.Fid.PersistentFileId = fid->persistent_fid;
        buf->dcontext.Fid.VolatileFileId = fid->volatile_fid;
        buf->dcontext.Flags = cpu_to_le32(SMB2_DHANDLE_FLAG_PERSISTENT);
        memcpy(buf->dcontext.CreateGuid, fid->create_guid, 16);

        /* SMB2_CREATE_DURABLE_HANDLE_RECONNECT_V2 is "DH2C" */
        buf->Name[0] = 'D';
        buf->Name[1] = 'H';
        buf->Name[2] = '2';
        buf->Name[3] = 'C';
        return buf;
}

static int
add_durable_v2_context(struct kvec *iov, unsigned int *num_iovec,
                    struct cifs_open_parms *oparms)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_durable_v2_buf(oparms);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_durable_v2);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset =
                        cpu_to_le32(sizeof(struct smb2_create_req) +
                                                                iov[1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_durable_v2));
        *num_iovec = num + 1;
        return 0;
}

static int
add_durable_reconnect_v2_context(struct kvec *iov, unsigned int *num_iovec,
                    struct cifs_open_parms *oparms)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        /* indicate that we don't need to relock the file */
        oparms->reconnect = false;

        iov[num].iov_base = create_reconnect_durable_v2_buf(oparms->fid);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_durable_handle_reconnect_v2);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset =
                        cpu_to_le32(sizeof(struct smb2_create_req) +
                                                                iov[1].iov_len);
        le32_add_cpu(&req->CreateContextsLength,
                        sizeof(struct create_durable_handle_reconnect_v2));
        *num_iovec = num + 1;
        return 0;
}

static int
add_durable_context(struct kvec *iov, unsigned int *num_iovec,
                    struct cifs_open_parms *oparms, bool use_persistent)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        if (use_persistent) {
                if (oparms->reconnect)
                        return add_durable_reconnect_v2_context(iov, num_iovec,
                                                                oparms);
                else
                        return add_durable_v2_context(iov, num_iovec, oparms);
        }

        if (oparms->reconnect) {
                iov[num].iov_base = create_reconnect_durable_buf(oparms->fid);
                /* indicate that we don't need to relock the file */
                oparms->reconnect = false;
        } else
                iov[num].iov_base = create_durable_buf();
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct create_durable);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset =
                        cpu_to_le32(sizeof(struct smb2_create_req) +
                                                                iov[1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct create_durable));
        *num_iovec = num + 1;
        return 0;
}

/* See MS-SMB2 2.2.13.2.7 */
static struct crt_twarp_ctxt *
create_twarp_buf(__u64 timewarp)
{
        struct crt_twarp_ctxt *buf;

        buf = kzalloc(sizeof(struct crt_twarp_ctxt), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct crt_twarp_ctxt, Timestamp));
        buf->ccontext.DataLength = cpu_to_le32(8);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct crt_twarp_ctxt, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_TIMEWARP_TOKEN is "TWrp" */
        buf->Name[0] = 'T';
        buf->Name[1] = 'W';
        buf->Name[2] = 'r';
        buf->Name[3] = 'p';
        buf->Timestamp = cpu_to_le64(timewarp);
        return buf;
}

/* See MS-SMB2 2.2.13.2.7 */
static int
add_twarp_context(struct kvec *iov, unsigned int *num_iovec, __u64 timewarp)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_twarp_buf(timewarp);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct crt_twarp_ctxt);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct crt_twarp_ctxt));
        *num_iovec = num + 1;
        return 0;
}

/* See See http://technet.microsoft.com/en-us/library/hh509017(v=ws.10).aspx */
static void setup_owner_group_sids(char *buf)
{
        struct owner_group_sids *sids = (struct owner_group_sids *)buf;

        /* Populate the user ownership fields S-1-5-88-1 */
        sids->owner.Revision = 1;
        sids->owner.NumAuth = 3;
        sids->owner.Authority[5] = 5;
        sids->owner.SubAuthorities[0] = cpu_to_le32(88);
        sids->owner.SubAuthorities[1] = cpu_to_le32(1);
        sids->owner.SubAuthorities[2] = cpu_to_le32(current_fsuid().val);

        /* Populate the group ownership fields S-1-5-88-2 */
        sids->group.Revision = 1;
        sids->group.NumAuth = 3;
        sids->group.Authority[5] = 5;
        sids->group.SubAuthorities[0] = cpu_to_le32(88);
        sids->group.SubAuthorities[1] = cpu_to_le32(2);
        sids->group.SubAuthorities[2] = cpu_to_le32(current_fsgid().val);

        cifs_dbg(FYI, "owner S-1-5-88-1-%d, group S-1-5-88-2-%d\n", current_fsuid().val, current_fsgid().val);
}

/* See MS-SMB2 2.2.13.2.2 and MS-DTYP 2.4.6 */
static struct crt_sd_ctxt *
create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
{
        struct crt_sd_ctxt *buf;
        __u8 *ptr, *aclptr;
        unsigned int acelen, acl_size, ace_count;
        unsigned int owner_offset = 0;
        unsigned int group_offset = 0;
        struct smb3_acl acl;

        *len = roundup(sizeof(struct crt_sd_ctxt) + (sizeof(struct cifs_ace) * 4), 8);

        if (set_owner) {
                /* sizeof(struct owner_group_sids) is already multiple of 8 so no need to round */
                *len += sizeof(struct owner_group_sids);
        }

        buf = kzalloc(*len, GFP_KERNEL);
        if (buf == NULL)
                return buf;

        ptr = (__u8 *)&buf[1];
        if (set_owner) {
                /* offset fields are from beginning of security descriptor not of create context */
                owner_offset = ptr - (__u8 *)&buf->sd;
                buf->sd.OffsetOwner = cpu_to_le32(owner_offset);
                group_offset = owner_offset + offsetof(struct owner_group_sids, group);
                buf->sd.OffsetGroup = cpu_to_le32(group_offset);

                setup_owner_group_sids(ptr);
                ptr += sizeof(struct owner_group_sids);
        } else {
                buf->sd.OffsetOwner = 0;
                buf->sd.OffsetGroup = 0;
        }

        buf->ccontext.DataOffset = cpu_to_le16(offsetof(struct crt_sd_ctxt, sd));
        buf->ccontext.NameOffset = cpu_to_le16(offsetof(struct crt_sd_ctxt, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_SD_BUFFER_TOKEN is "SecD" */
        buf->Name[0] = 'S';
        buf->Name[1] = 'e';
        buf->Name[2] = 'c';
        buf->Name[3] = 'D';
        buf->sd.Revision = 1;  /* Must be one see MS-DTYP 2.4.6 */

        /*
         * ACL is "self relative" ie ACL is stored in contiguous block of memory
         * and "DP" ie the DACL is present
         */
        buf->sd.Control = cpu_to_le16(ACL_CONTROL_SR | ACL_CONTROL_DP);

        /* offset owner, group and Sbz1 and SACL are all zero */
        buf->sd.OffsetDacl = cpu_to_le32(ptr - (__u8 *)&buf->sd);
        /* Ship the ACL for now. we will copy it into buf later. */
        aclptr = ptr;
        ptr += sizeof(struct smb3_acl);

        /* create one ACE to hold the mode embedded in reserved special SID */
        acelen = setup_special_mode_ACE((struct cifs_ace *)ptr, (__u64)mode);
        ptr += acelen;
        acl_size = acelen + sizeof(struct smb3_acl);
        ace_count = 1;

        if (set_owner) {
                /* we do not need to reallocate buffer to add the two more ACEs. plenty of space */
                acelen = setup_special_user_owner_ACE((struct cifs_ace *)ptr);
                ptr += acelen;
                acl_size += acelen;
                ace_count += 1;
        }

        /* and one more ACE to allow access for authenticated users */
        acelen = setup_authusers_ACE((struct cifs_ace *)ptr);
        ptr += acelen;
        acl_size += acelen;
        ace_count += 1;

        acl.AclRevision = ACL_REVISION; /* See 2.4.4.1 of MS-DTYP */
        acl.AclSize = cpu_to_le16(acl_size);
        acl.AceCount = cpu_to_le16(ace_count);
        memcpy(aclptr, &acl, sizeof(struct smb3_acl));

        buf->ccontext.DataLength = cpu_to_le32(ptr - (__u8 *)&buf->sd);
        *len = roundup(ptr - (__u8 *)buf, 8);

        return buf;
}

static int
add_sd_context(struct kvec *iov, unsigned int *num_iovec, umode_t mode, bool set_owner)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;
        unsigned int len = 0;

        iov[num].iov_base = create_sd_buf(mode, set_owner, &len);
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = len;
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, len);
        *num_iovec = num + 1;
        return 0;
}

static struct crt_query_id_ctxt *
create_query_id_buf(void)
{
        struct crt_query_id_ctxt *buf;

        buf = kzalloc(sizeof(struct crt_query_id_ctxt), GFP_KERNEL);
        if (!buf)
                return NULL;

        buf->ccontext.DataOffset = cpu_to_le16(0);
        buf->ccontext.DataLength = cpu_to_le32(0);
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct crt_query_id_ctxt, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_QUERY_ON_DISK_ID is "QFid" */
        buf->Name[0] = 'Q';
        buf->Name[1] = 'F';
        buf->Name[2] = 'i';
        buf->Name[3] = 'd';
        return buf;
}

/* See MS-SMB2 2.2.13.2.9 */
static int
add_query_id_context(struct kvec *iov, unsigned int *num_iovec)
{
        struct smb2_create_req *req = iov[0].iov_base;
        unsigned int num = *num_iovec;

        iov[num].iov_base = create_query_id_buf();
        if (iov[num].iov_base == NULL)
                return -ENOMEM;
        iov[num].iov_len = sizeof(struct crt_query_id_ctxt);
        if (!req->CreateContextsOffset)
                req->CreateContextsOffset = cpu_to_le32(
                                sizeof(struct smb2_create_req) +
                                iov[num - 1].iov_len);
        le32_add_cpu(&req->CreateContextsLength, sizeof(struct crt_query_id_ctxt));
        *num_iovec = num + 1;
        return 0;
}

static int
alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len,
                            const char *treename, const __le16 *path)
{
        int treename_len, path_len;
        struct nls_table *cp;
        const __le16 sep[] = {cpu_to_le16('\\'), cpu_to_le16(0x0000)};

        /*
         * skip leading "\\"
         */
        treename_len = strlen(treename);
        if (treename_len < 2 || !(treename[0] == '\\' && treename[1] == '\\'))
                return -EINVAL;

        treename += 2;
        treename_len -= 2;

        path_len = UniStrnlen((wchar_t *)path, PATH_MAX);

        /* make room for one path separator only if @path isn't empty */
        *out_len = treename_len + (path[0] ? 1 : 0) + path_len;

        /*
         * final path needs to be 8-byte aligned as specified in
         * MS-SMB2 2.2.13 SMB2 CREATE Request.
         */
        *out_size = roundup(*out_len * sizeof(__le16), 8);
        *out_path = kzalloc(*out_size + sizeof(__le16) /* null */, GFP_KERNEL);
        if (!*out_path)
                return -ENOMEM;

        cp = load_nls_default();
        cifs_strtoUTF16(*out_path, treename, treename_len, cp);

        /* Do not append the separator if the path is empty */
        if (path[0] != cpu_to_le16(0x0000)) {
                UniStrcat(*out_path, sep);
                UniStrcat(*out_path, path);
        }

        unload_nls(cp);

        return 0;
}

int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
                               umode_t mode, struct cifs_tcon *tcon,
                               const char *full_path,
                               struct cifs_sb_info *cifs_sb)
{
        struct smb_rqst rqst;
        struct smb2_create_req *req;
        struct smb2_create_rsp *rsp = NULL;
        struct cifs_ses *ses = tcon->ses;
        struct kvec iov[3]; /* make sure at least one for each open context */
        struct kvec rsp_iov = {NULL, 0};
        int resp_buftype;
        int uni_path_len;
        __le16 *copy_path = NULL;
        int copy_size;
        int rc = 0;
        unsigned int n_iov = 2;
        __u32 file_attributes = 0;
        char *pc_buf = NULL;
        int flags = 0;
        unsigned int total_len;
        __le16 *utf16_path = NULL;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);

        cifs_dbg(FYI, "mkdir\n");

        /* resource #1: path allocation */
        utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
        if (!utf16_path)
                return -ENOMEM;

        if (!ses || !server) {
                rc = -EIO;
                goto err_free_path;
        }

        /* resource #2: request */
        rc = smb2_plain_req_init(SMB2_CREATE, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                goto err_free_path;


        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        req->ImpersonationLevel = IL_IMPERSONATION;
        req->DesiredAccess = cpu_to_le32(FILE_WRITE_ATTRIBUTES);
        /* 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(FILE_CREATE);
        req->CreateOptions = cpu_to_le32(CREATE_NOT_FILE);

        iov[0].iov_base = (char *)req;
        /* -1 since last byte is buf[0] which is sent below (path) */
        iov[0].iov_len = total_len - 1;

        req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req));

        /* [MS-SMB2] 2.2.13 NameOffset:
         * If SMB2_FLAGS_DFS_OPERATIONS is set in the Flags field of
         * the SMB2 header, the file name includes a prefix that will
         * be processed during DFS name normalization as specified in
         * section 3.3.5.9. Otherwise, the file name is relative to
         * the share that is identified by the TreeId in the SMB2
         * header.
         */
        if (tcon->share_flags & SHI1005_FLAGS_DFS) {
                int name_len;

                req->hdr.Flags |= SMB2_FLAGS_DFS_OPERATIONS;
                rc = alloc_path_with_tree_prefix(&copy_path, &copy_size,
                                                 &name_len,
                                                 tcon->treeName, utf16_path);
                if (rc)
                        goto err_free_req;

                req->NameLength = cpu_to_le16(name_len * 2);
                uni_path_len = copy_size;
                /* free before overwriting resource */
                kfree(utf16_path);
                utf16_path = copy_path;
        } else {
                uni_path_len = (2 * UniStrnlen((wchar_t *)utf16_path, PATH_MAX)) + 2;
                /* MUST set path len (NameLength) to 0 opening root of share */
                req->NameLength = cpu_to_le16(uni_path_len - 2);
                if (uni_path_len % 8 != 0) {
                        copy_size = roundup(uni_path_len, 8);
                        copy_path = kzalloc(copy_size, GFP_KERNEL);
                        if (!copy_path) {
                                rc = -ENOMEM;
                                goto err_free_req;
                        }
                        memcpy((char *)copy_path, (const char *)utf16_path,
                               uni_path_len);
                        uni_path_len = copy_size;
                        /* free before overwriting resource */
                        kfree(utf16_path);
                        utf16_path = copy_path;
                }
        }

        iov[1].iov_len = uni_path_len;
        iov[1].iov_base = utf16_path;
        req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_NONE;

        if (tcon->posix_extensions) {
                /* resource #3: posix buf */
                rc = add_posix_context(iov, &n_iov, mode);
                if (rc)
                        goto err_free_req;
                pc_buf = iov[n_iov-1].iov_base;
        }


        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = n_iov;

        /* no need to inc num_remote_opens because we close it just below */
        trace_smb3_posix_mkdir_enter(xid, tcon->tid, ses->Suid, CREATE_NOT_FILE,
                                    FILE_WRITE_ATTRIBUTES);
        /* resource #4: response buffer */
        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
                trace_smb3_posix_mkdir_err(xid, tcon->tid, ses->Suid,
                                           CREATE_NOT_FILE,
                                           FILE_WRITE_ATTRIBUTES, rc);
                goto err_free_rsp_buf;
        }

        /*
         * Although unlikely to be possible for rsp to be null and rc not set,
         * adding check below is slightly safer long term (and quiets Coverity
         * warning)
         */
        rsp = (struct smb2_create_rsp *)rsp_iov.iov_base;
        if (rsp == NULL) {
                rc = -EIO;
                kfree(pc_buf);
                goto err_free_req;
        }

        trace_smb3_posix_mkdir_done(xid, rsp->PersistentFileId, tcon->tid, ses->Suid,
                                    CREATE_NOT_FILE, FILE_WRITE_ATTRIBUTES);

        SMB2_close(xid, tcon, rsp->PersistentFileId, rsp->VolatileFileId);

        /* Eventually save off posix specific response info and timestaps */

err_free_rsp_buf:
        free_rsp_buf(resp_buftype, rsp);
        kfree(pc_buf);
err_free_req:
        cifs_small_buf_release(req);
err_free_path:
        kfree(utf16_path);
        return rc;
}

int
SMB2_open_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
               struct smb_rqst *rqst, __u8 *oplock,
               struct cifs_open_parms *oparms, __le16 *path)
{
        struct smb2_create_req *req;
        unsigned int n_iov = 2;
        __u32 file_attributes = 0;
        int copy_size;
        int uni_path_len;
        unsigned int total_len;
        struct kvec *iov = rqst->rq_iov;
        __le16 *copy_path;
        int rc;

        rc = smb2_plain_req_init(SMB2_CREATE, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        iov[0].iov_base = (char *)req;
        /* -1 since last byte is buf[0] which is sent below (path) */
        iov[0].iov_len = total_len - 1;

        if (oparms->create_options & CREATE_OPTION_READONLY)
                file_attributes |= ATTR_READONLY;
        if (oparms->create_options & CREATE_OPTION_SPECIAL)
                file_attributes |= ATTR_SYSTEM;

        req->ImpersonationLevel = IL_IMPERSONATION;
        req->DesiredAccess = cpu_to_le32(oparms->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(oparms->disposition);
        req->CreateOptions = cpu_to_le32(oparms->create_options & CREATE_OPTIONS_MASK);
        req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req));

        /* [MS-SMB2] 2.2.13 NameOffset:
         * If SMB2_FLAGS_DFS_OPERATIONS is set in the Flags field of
         * the SMB2 header, the file name includes a prefix that will
         * be processed during DFS name normalization as specified in
         * section 3.3.5.9. Otherwise, the file name is relative to
         * the share that is identified by the TreeId in the SMB2
         * header.
         */
        if (tcon->share_flags & SHI1005_FLAGS_DFS) {
                int name_len;

                req->hdr.Flags |= SMB2_FLAGS_DFS_OPERATIONS;
                rc = alloc_path_with_tree_prefix(&copy_path, &copy_size,
                                                 &name_len,
                                                 tcon->treeName, path);
                if (rc)
                        return rc;
                req->NameLength = cpu_to_le16(name_len * 2);
                uni_path_len = copy_size;
                path = copy_path;
        } else {
                uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;
                /* MUST set path len (NameLength) to 0 opening root of share */
                req->NameLength = cpu_to_le16(uni_path_len - 2);
                copy_size = uni_path_len;
                if (copy_size % 8 != 0)
                        copy_size = roundup(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;

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

        if (!(server->capabilities & SMB2_GLOBAL_CAP_LEASING) ||
            *oplock == SMB2_OPLOCK_LEVEL_NONE)
                req->RequestedOplockLevel = *oplock;
        else if (!(server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING) &&
                  (oparms->create_options & CREATE_NOT_FILE))
                req->RequestedOplockLevel = *oplock; /* no srv lease support */
        else {
                rc = add_lease_context(server, iov, &n_iov,
                                       oparms->fid->lease_key, oplock);
                if (rc)
                        return rc;
        }

        if (*oplock == SMB2_OPLOCK_LEVEL_BATCH) {
                /* need to set Next field of lease context if we request it */
                if (server->capabilities & SMB2_GLOBAL_CAP_LEASING) {
                        struct create_context *ccontext =
                            (struct create_context *)iov[n_iov-1].iov_base;
                        ccontext->Next =
                                cpu_to_le32(server->vals->create_lease_size);
                }

                rc = add_durable_context(iov, &n_iov, oparms,
                                        tcon->use_persistent);
                if (rc)
                        return rc;
        }

        if (tcon->posix_extensions) {
                if (n_iov > 2) {
                        struct create_context *ccontext =
                            (struct create_context *)iov[n_iov-1].iov_base;
                        ccontext->Next =
                                cpu_to_le32(iov[n_iov-1].iov_len);
                }

                rc = add_posix_context(iov, &n_iov, oparms->mode);
                if (rc)
                        return rc;
        }

        if (tcon->snapshot_time) {
                cifs_dbg(FYI, "adding snapshot context\n");
                if (n_iov > 2) {
                        struct create_context *ccontext =
                            (struct create_context *)iov[n_iov-1].iov_base;
                        ccontext->Next =
                                cpu_to_le32(iov[n_iov-1].iov_len);
                }

                rc = add_twarp_context(iov, &n_iov, tcon->snapshot_time);
                if (rc)
                        return rc;
        }

        if ((oparms->disposition != FILE_OPEN) && (oparms->cifs_sb)) {
                bool set_mode;
                bool set_owner;

                if ((oparms->cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID) &&
                    (oparms->mode != ACL_NO_MODE))
                        set_mode = true;
                else {
                        set_mode = false;
                        oparms->mode = ACL_NO_MODE;
                }

                if (oparms->cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UID_FROM_ACL)
                        set_owner = true;
                else
                        set_owner = false;

                if (set_owner | set_mode) {
                        if (n_iov > 2) {
                                struct create_context *ccontext =
                                    (struct create_context *)iov[n_iov-1].iov_base;
                                ccontext->Next = cpu_to_le32(iov[n_iov-1].iov_len);
                        }

                        cifs_dbg(FYI, "add sd with mode 0x%x\n", oparms->mode);
                        rc = add_sd_context(iov, &n_iov, oparms->mode, set_owner);
                        if (rc)
                                return rc;
                }
        }

        if (n_iov > 2) {
                struct create_context *ccontext =
                        (struct create_context *)iov[n_iov-1].iov_base;
                ccontext->Next = cpu_to_le32(iov[n_iov-1].iov_len);
        }
        add_query_id_context(iov, &n_iov);

        rqst->rq_nvec = n_iov;
        return 0;
}

/* rq_iov[0] is the request and is released by cifs_small_buf_release().
 * All other vectors are freed by kfree().
 */
void
SMB2_open_free(struct smb_rqst *rqst)
{
        int i;

        if (rqst && rqst->rq_iov) {
                cifs_small_buf_release(rqst->rq_iov[0].iov_base);
                for (i = 1; i < rqst->rq_nvec; i++)
                        if (rqst->rq_iov[i].iov_base != smb2_padding)
                                kfree(rqst->rq_iov[i].iov_base);
        }
}

int
SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
          __u8 *oplock, struct smb2_file_all_info *buf,
          struct create_posix_rsp *posix,
          struct kvec *err_iov, int *buftype)
{
        struct smb_rqst rqst;
        struct smb2_create_rsp *rsp = NULL;
        struct cifs_tcon *tcon = oparms->tcon;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        struct kvec iov[SMB2_CREATE_IOV_SIZE];
        struct kvec rsp_iov = {NULL, 0};
        int resp_buftype = CIFS_NO_BUFFER;
        int rc = 0;
        int flags = 0;

        cifs_dbg(FYI, "create/open\n");
        if (!ses || !server)
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = SMB2_CREATE_IOV_SIZE;

        rc = SMB2_open_init(tcon, server,
                            &rqst, oplock, oparms, path);
        if (rc)
                goto creat_exit;

        trace_smb3_open_enter(xid, tcon->tid, tcon->ses->Suid,
                oparms->create_options, oparms->desired_access);

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags,
                            &rsp_iov);
        rsp = (struct smb2_create_rsp *)rsp_iov.iov_base;

        if (rc != 0) {
                cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
                if (err_iov && rsp) {
                        *err_iov = rsp_iov;
                        *buftype = resp_buftype;
                        resp_buftype = CIFS_NO_BUFFER;
                        rsp = NULL;
                }
                trace_smb3_open_err(xid, tcon->tid, ses->Suid,
                                    oparms->create_options, oparms->desired_access, rc);
                if (rc == -EREMCHG) {
                        pr_warn_once("server share %s deleted\n",
                                     tcon->treeName);
                        tcon->need_reconnect = true;
                }
                goto creat_exit;
        } else if (rsp == NULL) /* unlikely to happen, but safer to check */
                goto creat_exit;
        else
                trace_smb3_open_done(xid, rsp->PersistentFileId, tcon->tid, ses->Suid,
                                     oparms->create_options, oparms->desired_access);

        atomic_inc(&tcon->num_remote_opens);
        oparms->fid->persistent_fid = rsp->PersistentFileId;
        oparms->fid->volatile_fid = rsp->VolatileFileId;
        oparms->fid->access = oparms->desired_access;
#ifdef CONFIG_CIFS_DEBUG2
        oparms->fid->mid = le64_to_cpu(rsp->hdr.MessageId);
#endif /* CIFS_DEBUG2 */

        if (buf) {
                buf->CreationTime = rsp->CreationTime;
                buf->LastAccessTime = rsp->LastAccessTime;
                buf->LastWriteTime = rsp->LastWriteTime;
                buf->ChangeTime = rsp->ChangeTime;
                buf->AllocationSize = rsp->AllocationSize;
                buf->EndOfFile = rsp->EndofFile;
                buf->Attributes = rsp->FileAttributes;
                buf->NumberOfLinks = cpu_to_le32(1);
                buf->DeletePending = 0;
        }


        smb2_parse_contexts(server, rsp, &oparms->fid->epoch,
                            oparms->fid->lease_key, oplock, buf, posix);
creat_exit:
        SMB2_open_free(&rqst);
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

int
SMB2_ioctl_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
                struct smb_rqst *rqst,
                u64 persistent_fid, u64 volatile_fid, u32 opcode,
                char *in_data, u32 indatalen,
                __u32 max_response_size)
{
        struct smb2_ioctl_req *req;
        struct kvec *iov = rqst->rq_iov;
        unsigned int total_len;
        int rc;
        char *in_data_buf;

        rc = smb2_ioctl_req_init(opcode, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        if (indatalen) {
                /*
                 * indatalen is usually small at a couple of bytes max, so
                 * just allocate through generic pool
                 */
                in_data_buf = kmemdup(in_data, indatalen, GFP_NOFS);
                if (!in_data_buf) {
                        cifs_small_buf_release(req);
                        return -ENOMEM;
                }
        }

        req->CtlCode = cpu_to_le32(opcode);
        req->PersistentFileId = persistent_fid;
        req->VolatileFileId = volatile_fid;

        iov[0].iov_base = (char *)req;
        /*
         * If no input data, the size of ioctl struct in
         * protocol spec still includes a 1 byte data buffer,
         * but if input data passed to ioctl, we do not
         * want to double count this, so we do not send
         * the dummy one byte of data in iovec[0] if sending
         * input data (in iovec[1]).
         */
        if (indatalen) {
                req->InputCount = cpu_to_le32(indatalen);
                /* do not set InputOffset if no input data */
                req->InputOffset =
                       cpu_to_le32(offsetof(struct smb2_ioctl_req, Buffer));
                rqst->rq_nvec = 2;
                iov[0].iov_len = total_len - 1;
                iov[1].iov_base = in_data_buf;
                iov[1].iov_len = indatalen;
        } else {
                rqst->rq_nvec = 1;
                iov[0].iov_len = total_len;
        }

        req->OutputOffset = 0;
        req->OutputCount = 0; /* MBZ */

        /*
         * In most cases max_response_size is set to 16K (CIFSMaxBufSize)
         * We Could increase default MaxOutputResponse, but that could require
         * more credits. Windows typically sets this smaller, but for some
         * ioctls it may be useful to allow server to send more. No point
         * limiting what the server can send as long as fits in one credit
         * We can not handle more than CIFS_MAX_BUF_SIZE yet but may want
         * to increase this limit up in the future.
         * Note that for snapshot queries that servers like Azure expect that
         * the first query be minimal size (and just used to get the number/size
         * of previous versions) so response size must be specified as EXACTLY
         * sizeof(struct snapshot_array) which is 16 when rounded up to multiple
         * of eight bytes.  Currently that is the only case where we set max
         * response size smaller.
         */
        req->MaxOutputResponse = cpu_to_le32(max_response_size);
        req->hdr.CreditCharge =
                cpu_to_le16(DIV_ROUND_UP(max(indatalen, max_response_size),
                                         SMB2_MAX_BUFFER_SIZE));
        /* always an FSCTL (for now) */
        req->Flags = cpu_to_le32(SMB2_0_IOCTL_IS_FSCTL);

        /* validate negotiate request must be signed - see MS-SMB2 3.2.5.5 */
        if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO)
                req->hdr.Flags |= SMB2_FLAGS_SIGNED;

        return 0;
}

void
SMB2_ioctl_free(struct smb_rqst *rqst)
{
        int i;
        if (rqst && rqst->rq_iov) {
                cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
                for (i = 1; i < rqst->rq_nvec; i++)
                        if (rqst->rq_iov[i].iov_base != smb2_padding)
                                kfree(rqst->rq_iov[i].iov_base);
        }
}


/*
 *      SMB2 IOCTL is used for both IOCTLs and FSCTLs
 */
int
SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
           u64 volatile_fid, u32 opcode, char *in_data, u32 indatalen,
           u32 max_out_data_len, char **out_data,
           u32 *plen /* returned data len */)
{
        struct smb_rqst rqst;
        struct smb2_ioctl_rsp *rsp = NULL;
        struct cifs_ses *ses;
        struct TCP_Server_Info *server;
        struct kvec iov[SMB2_IOCTL_IOV_SIZE];
        struct kvec rsp_iov = {NULL, 0};
        int resp_buftype = CIFS_NO_BUFFER;
        int rc = 0;
        int flags = 0;

        cifs_dbg(FYI, "SMB2 IOCTL\n");

        if (out_data != NULL)
                *out_data = NULL;

        /* zero out returned data len, in case of error */
        if (plen)
                *plen = 0;

        if (!tcon)
                return -EIO;

        ses = tcon->ses;
        if (!ses)
                return -EIO;

        server = cifs_pick_channel(ses);
        if (!server)
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = SMB2_IOCTL_IOV_SIZE;

        rc = SMB2_ioctl_init(tcon, server,
                             &rqst, persistent_fid, volatile_fid, opcode,
                             in_data, indatalen, max_out_data_len);
        if (rc)
                goto ioctl_exit;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags,
                            &rsp_iov);
        rsp = (struct smb2_ioctl_rsp *)rsp_iov.iov_base;

        if (rc != 0)
                trace_smb3_fsctl_err(xid, persistent_fid, tcon->tid,
                                ses->Suid, 0, opcode, rc);

        if ((rc != 0) && (rc != -EINVAL) && (rc != -E2BIG)) {
                cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
                goto ioctl_exit;
        } else if (rc == -EINVAL) {
                if ((opcode != FSCTL_SRV_COPYCHUNK_WRITE) &&
                    (opcode != FSCTL_SRV_COPYCHUNK)) {
                        cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
                        goto ioctl_exit;
                }
        } else if (rc == -E2BIG) {
                if (opcode != FSCTL_QUERY_ALLOCATED_RANGES) {
                        cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
                        goto ioctl_exit;
                }
        }

        /* check if caller wants to look at return data or just return rc */
        if ((plen == NULL) || (out_data == NULL))
                goto ioctl_exit;

        /*
         * Although unlikely to be possible for rsp to be null and rc not set,
         * adding check below is slightly safer long term (and quiets Coverity
         * warning)
         */
        if (rsp == NULL) {
                rc = -EIO;
                goto ioctl_exit;
        }

        *plen = le32_to_cpu(rsp->OutputCount);

        /* We check for obvious errors in the output buffer length and offset */
        if (*plen == 0)
                goto ioctl_exit; /* server returned no data */
        else if (*plen > rsp_iov.iov_len || *plen > 0xFF00) {
                cifs_tcon_dbg(VFS, "srv returned invalid ioctl length: %d\n", *plen);
                *plen = 0;
                rc = -EIO;
                goto ioctl_exit;
        }

        if (rsp_iov.iov_len - *plen < le32_to_cpu(rsp->OutputOffset)) {
                cifs_tcon_dbg(VFS, "Malformed ioctl resp: len %d offset %d\n", *plen,
                        le32_to_cpu(rsp->OutputOffset));
                *plen = 0;
                rc = -EIO;
                goto ioctl_exit;
        }

        *out_data = kmemdup((char *)rsp + le32_to_cpu(rsp->OutputOffset),
                            *plen, GFP_KERNEL);
        if (*out_data == NULL) {
                rc = -ENOMEM;
                goto ioctl_exit;
        }

ioctl_exit:
        SMB2_ioctl_free(&rqst);
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

/*
 *   Individual callers to ioctl worker function follow
 */

int
SMB2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
                     u64 persistent_fid, u64 volatile_fid)
{
        int rc;
        struct  compress_ioctl fsctl_input;
        char *ret_data = NULL;

        fsctl_input.CompressionState =
                        cpu_to_le16(COMPRESSION_FORMAT_DEFAULT);

        rc = SMB2_ioctl(xid, tcon, persistent_fid, volatile_fid,
                        FSCTL_SET_COMPRESSION,
                        (char *)&fsctl_input /* data input */,
                        2 /* in data len */, CIFSMaxBufSize /* max out data */,
                        &ret_data /* out data */, NULL);

        cifs_dbg(FYI, "set compression rc %d\n", rc);

        return rc;
}

int
SMB2_close_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
                struct smb_rqst *rqst,
                u64 persistent_fid, u64 volatile_fid, bool query_attrs)
{
        struct smb2_close_req *req;
        struct kvec *iov = rqst->rq_iov;
        unsigned int total_len;
        int rc;

        rc = smb2_plain_req_init(SMB2_CLOSE, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        req->PersistentFileId = persistent_fid;
        req->VolatileFileId = volatile_fid;
        if (query_attrs)
                req->Flags = SMB2_CLOSE_FLAG_POSTQUERY_ATTRIB;
        else
                req->Flags = 0;
        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        return 0;
}

void
SMB2_close_free(struct smb_rqst *rqst)
{
        if (rqst && rqst->rq_iov)
                cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
}

int
__SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
             u64 persistent_fid, u64 volatile_fid,
             struct smb2_file_network_open_info *pbuf)
{
        struct smb_rqst rqst;
        struct smb2_close_rsp *rsp = NULL;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        struct kvec iov[1];
        struct kvec rsp_iov;
        int resp_buftype = CIFS_NO_BUFFER;
        int rc = 0;
        int flags = 0;
        bool query_attrs = false;

        cifs_dbg(FYI, "Close\n");

        if (!ses || !server)
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        /* check if need to ask server to return timestamps in close response */
        if (pbuf)
                query_attrs = true;

        trace_smb3_close_enter(xid, persistent_fid, tcon->tid, ses->Suid);
        rc = SMB2_close_init(tcon, server,
                             &rqst, persistent_fid, volatile_fid,
                             query_attrs);
        if (rc)
                goto close_exit;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        rsp = (struct smb2_close_rsp *)rsp_iov.iov_base;

        if (rc != 0) {
                cifs_stats_fail_inc(tcon, SMB2_CLOSE_HE);
                trace_smb3_close_err(xid, persistent_fid, tcon->tid, ses->Suid,
                                     rc);
                goto close_exit;
        } else {
                trace_smb3_close_done(xid, persistent_fid, tcon->tid,
                                      ses->Suid);
                /*
                 * Note that have to subtract 4 since struct network_open_info
                 * has a final 4 byte pad that close response does not have
                 */
                if (pbuf)
                        memcpy(pbuf, (char *)&rsp->CreationTime, sizeof(*pbuf) - 4);
        }

        atomic_dec(&tcon->num_remote_opens);
close_exit:
        SMB2_close_free(&rqst);
        free_rsp_buf(resp_buftype, rsp);

        /* retry close in a worker thread if this one is interrupted */
        if (is_interrupt_error(rc)) {
                int tmp_rc;

                tmp_rc = smb2_handle_cancelled_close(tcon, persistent_fid,
                                                     volatile_fid);
                if (tmp_rc)
                        cifs_dbg(VFS, "handle cancelled close fid 0x%llx returned error %d\n",
                                 persistent_fid, tmp_rc);
        }
        return rc;
}

int
SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
                u64 persistent_fid, u64 volatile_fid)
{
        return __SMB2_close(xid, tcon, persistent_fid, volatile_fid, NULL);
}

int
smb2_validate_iov(unsigned int offset, unsigned int buffer_length,
                  struct kvec *iov, unsigned int min_buf_size)
{
        unsigned int smb_len = iov->iov_len;
        char *end_of_smb = smb_len + (char *)iov->iov_base;
        char *begin_of_buf = offset + (char *)iov->iov_base;
        char *end_of_buf = begin_of_buf + buffer_length;


        if (buffer_length < min_buf_size) {
                cifs_dbg(VFS, "buffer length %d smaller than minimum size %d\n",
                         buffer_length, min_buf_size);
                return -EINVAL;
        }

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

        if ((begin_of_buf > end_of_smb) || (end_of_buf > end_of_smb)) {
                cifs_dbg(VFS, "Invalid server response, bad offset to data\n");
                return -EINVAL;
        }

        return 0;
}

/*
 * If SMB buffer fields are valid, copy into temporary buffer to hold result.
 * Caller must free buffer.
 */
int
smb2_validate_and_copy_iov(unsigned int offset, unsigned int buffer_length,
                           struct kvec *iov, unsigned int minbufsize,
                           char *data)
{
        char *begin_of_buf = offset + (char *)iov->iov_base;
        int rc;

        if (!data)
                return -EINVAL;

        rc = smb2_validate_iov(offset, buffer_length, iov, minbufsize);
        if (rc)
                return rc;

        memcpy(data, begin_of_buf, buffer_length);

        return 0;
}

int
SMB2_query_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
                     struct smb_rqst *rqst,
                     u64 persistent_fid, u64 volatile_fid,
                     u8 info_class, u8 info_type, u32 additional_info,
                     size_t output_len, size_t input_len, void *input)
{
        struct smb2_query_info_req *req;
        struct kvec *iov = rqst->rq_iov;
        unsigned int total_len;
        int rc;

        rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        req->InfoType = info_type;
        req->FileInfoClass = info_class;
        req->PersistentFileId = persistent_fid;
        req->VolatileFileId = volatile_fid;
        req->AdditionalInformation = cpu_to_le32(additional_info);

        req->OutputBufferLength = cpu_to_le32(output_len);
        if (input_len) {
                req->InputBufferLength = cpu_to_le32(input_len);
                /* total_len for smb query request never close to le16 max */
                req->InputBufferOffset = cpu_to_le16(total_len - 1);
                memcpy(req->Buffer, input, input_len);
        }

        iov[0].iov_base = (char *)req;
        /* 1 for Buffer */
        iov[0].iov_len = total_len - 1 + input_len;
        return 0;
}

void
SMB2_query_info_free(struct smb_rqst *rqst)
{
        if (rqst && rqst->rq_iov)
                cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
}

static int
query_info(const unsigned int xid, struct cifs_tcon *tcon,
           u64 persistent_fid, u64 volatile_fid, u8 info_class, u8 info_type,
           u32 additional_info, size_t output_len, size_t min_len, void **data,
                u32 *dlen)
{
        struct smb_rqst rqst;
        struct smb2_query_info_rsp *rsp = NULL;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int rc = 0;
        int resp_buftype = CIFS_NO_BUFFER;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server;
        int flags = 0;
        bool allocated = false;

        cifs_dbg(FYI, "Query Info\n");

        if (!ses)
                return -EIO;
        server = cifs_pick_channel(ses);
        if (!server)
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = SMB2_query_info_init(tcon, server,
                                  &rqst, persistent_fid, volatile_fid,
                                  info_class, info_type, additional_info,
                                  output_len, 0, NULL);
        if (rc)
                goto qinf_exit;

        trace_smb3_query_info_enter(xid, persistent_fid, tcon->tid,
                                    ses->Suid, info_class, (__u32)info_type);

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        rsp = (struct smb2_query_info_rsp *)rsp_iov.iov_base;

        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
                trace_smb3_query_info_err(xid, persistent_fid, tcon->tid,
                                ses->Suid, info_class, (__u32)info_type, rc);
                goto qinf_exit;
        }

        trace_smb3_query_info_done(xid, persistent_fid, tcon->tid,
                                ses->Suid, info_class, (__u32)info_type);

        if (dlen) {
                *dlen = le32_to_cpu(rsp->OutputBufferLength);
                if (!*data) {
                        *data = kmalloc(*dlen, GFP_KERNEL);
                        if (!*data) {
                                cifs_tcon_dbg(VFS,
                                        "Error %d allocating memory for acl\n",
                                        rc);
                                *dlen = 0;
                                rc = -ENOMEM;
                                goto qinf_exit;
                        }
                        allocated = true;
                }
        }

        rc = smb2_validate_and_copy_iov(le16_to_cpu(rsp->OutputBufferOffset),
                                        le32_to_cpu(rsp->OutputBufferLength),
                                        &rsp_iov, min_len, *data);
        if (rc && allocated) {
                kfree(*data);
                *data = NULL;
                *dlen = 0;
        }

qinf_exit:
        SMB2_query_info_free(&rqst);
        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, SMB2_O_INFO_FILE, 0,
                          sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
                          sizeof(struct smb2_file_all_info), (void **)&data,
                          NULL);
}

#if 0
/* currently unused, as now we are doing compounding instead (see smb311_posix_query_path_info) */
int
SMB311_posix_query_info(const unsigned int xid, struct cifs_tcon *tcon,
                u64 persistent_fid, u64 volatile_fid, struct smb311_posix_qinfo *data, u32 *plen)
{
        size_t output_len = sizeof(struct smb311_posix_qinfo *) +
                        (sizeof(struct cifs_sid) * 2) + (PATH_MAX * 2);
        *plen = 0;

        return query_info(xid, tcon, persistent_fid, volatile_fid,
                          SMB_FIND_FILE_POSIX_INFO, SMB2_O_INFO_FILE, 0,
                          output_len, sizeof(struct smb311_posix_qinfo), (void **)&data, plen);
        /* Note caller must free "data" (passed in above). It may be allocated in query_info call */
}
#endif

int
SMB2_query_acl(const unsigned int xid, struct cifs_tcon *tcon,
               u64 persistent_fid, u64 volatile_fid,
               void **data, u32 *plen, u32 extra_info)
{
        __u32 additional_info = OWNER_SECINFO | GROUP_SECINFO | DACL_SECINFO |
                                extra_info;
        *plen = 0;

        return query_info(xid, tcon, persistent_fid, volatile_fid,
                          0, SMB2_O_INFO_SECURITY, additional_info,
                          SMB2_MAX_BUFFER_SIZE, MIN_SEC_DESC_LEN, data, plen);
}

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, SMB2_O_INFO_FILE, 0,
                          sizeof(struct smb2_file_internal_info),
                          sizeof(struct smb2_file_internal_info),
                          (void **)&uniqueid, NULL);
}

/*
 * CHANGE_NOTIFY Request is sent to get notifications on changes to a directory
 * See MS-SMB2 2.2.35 and 2.2.36
 */

static int
SMB2_notify_init(const unsigned int xid, struct smb_rqst *rqst,
                 struct cifs_tcon *tcon, struct TCP_Server_Info *server,
                 u64 persistent_fid, u64 volatile_fid,
                 u32 completion_filter, bool watch_tree)
{
        struct smb2_change_notify_req *req;
        struct kvec *iov = rqst->rq_iov;
        unsigned int total_len;
        int rc;

        rc = smb2_plain_req_init(SMB2_CHANGE_NOTIFY, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        req->PersistentFileId = persistent_fid;
        req->VolatileFileId = volatile_fid;
        /* See note 354 of MS-SMB2, 64K max */
        req->OutputBufferLength =
                cpu_to_le32(SMB2_MAX_BUFFER_SIZE - MAX_SMB2_HDR_SIZE);
        req->CompletionFilter = cpu_to_le32(completion_filter);
        if (watch_tree)
                req->Flags = cpu_to_le16(SMB2_WATCH_TREE);
        else
                req->Flags = 0;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        return 0;
}

int
SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
                u64 persistent_fid, u64 volatile_fid, bool watch_tree,
                u32 completion_filter)
{
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        struct smb_rqst rqst;
        struct kvec iov[1];
        struct kvec rsp_iov = {NULL, 0};
        int resp_buftype = CIFS_NO_BUFFER;
        int flags = 0;
        int rc = 0;

        cifs_dbg(FYI, "change notify\n");
        if (!ses || !server)
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = SMB2_notify_init(xid, &rqst, tcon, server,
                              persistent_fid, volatile_fid,
                              completion_filter, watch_tree);
        if (rc)
                goto cnotify_exit;

        trace_smb3_notify_enter(xid, persistent_fid, tcon->tid, ses->Suid,
                                (u8)watch_tree, completion_filter);
        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);

        if (rc != 0) {
                cifs_stats_fail_inc(tcon, SMB2_CHANGE_NOTIFY_HE);
                trace_smb3_notify_err(xid, persistent_fid, tcon->tid, ses->Suid,
                                (u8)watch_tree, completion_filter, rc);
        } else
                trace_smb3_notify_done(xid, persistent_fid, tcon->tid,
                                ses->Suid, (u8)watch_tree, completion_filter);

 cnotify_exit:
        if (rqst.rq_iov)
                cifs_small_buf_release(rqst.rq_iov[0].iov_base); /* request */
        free_rsp_buf(resp_buftype, rsp_iov.iov_base);
        return rc;
}



/*
 * 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 *rsp = (struct smb2_echo_rsp *)mid->resp_buf;
        struct cifs_credits credits = { .value = 0, .instance = 0 };

        if (mid->mid_state == MID_RESPONSE_RECEIVED
            || mid->mid_state == MID_RESPONSE_MALFORMED) {
                credits.value = le16_to_cpu(rsp->hdr.CreditRequest);
                credits.instance = server->reconnect_instance;
        }

        release_mid(mid);
        add_credits(server, &credits, CIFS_ECHO_OP);
}

void smb2_reconnect_server(struct work_struct *work)
{
        struct TCP_Server_Info *server = container_of(work,
                                        struct TCP_Server_Info, reconnect.work);
        struct TCP_Server_Info *pserver;
        struct cifs_ses *ses, *ses2;
        struct cifs_tcon *tcon, *tcon2;
        struct list_head tmp_list, tmp_ses_list;
        bool tcon_exist = false, ses_exist = false;
        bool tcon_selected = false;
        int rc;
        bool resched = false;

        /* If server is a channel, select the primary channel */
        pserver = CIFS_SERVER_IS_CHAN(server) ? server->primary_server : server;

        /* Prevent simultaneous reconnects that can corrupt tcon->rlist list */
        mutex_lock(&pserver->reconnect_mutex);

        INIT_LIST_HEAD(&tmp_list);
        INIT_LIST_HEAD(&tmp_ses_list);
        cifs_dbg(FYI, "Reconnecting tcons and channels\n");

        spin_lock(&cifs_tcp_ses_lock);
        list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {

                tcon_selected = false;

                list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
                        if (tcon->need_reconnect || tcon->need_reopen_files) {
                                tcon->tc_count++;
                                list_add_tail(&tcon->rlist, &tmp_list);
                                tcon_selected = tcon_exist = true;
                        }
                }
                /*
                 * IPC has the same lifetime as its session and uses its
                 * refcount.
                 */
                if (ses->tcon_ipc && ses->tcon_ipc->need_reconnect) {
                        list_add_tail(&ses->tcon_ipc->rlist, &tmp_list);
                        tcon_selected = tcon_exist = true;
                        ses->ses_count++;
                }
                /*
                 * handle the case where channel needs to reconnect
                 * binding session, but tcon is healthy (some other channel
                 * is active)
                 */
                spin_lock(&ses->chan_lock);
                if (!tcon_selected && cifs_chan_needs_reconnect(ses, server)) {
                        list_add_tail(&ses->rlist, &tmp_ses_list);
                        ses_exist = true;
                        ses->ses_count++;
                }
                spin_unlock(&ses->chan_lock);
        }
        /*
         * Get the reference to server struct to be sure that the last call of
         * cifs_put_tcon() in the loop below won't release the server pointer.
         */
        if (tcon_exist || ses_exist)
                server->srv_count++;

        spin_unlock(&cifs_tcp_ses_lock);

        list_for_each_entry_safe(tcon, tcon2, &tmp_list, rlist) {
                rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server);
                if (!rc)
                        cifs_reopen_persistent_handles(tcon);
                else
                        resched = true;
                list_del_init(&tcon->rlist);
                if (tcon->ipc)
                        cifs_put_smb_ses(tcon->ses);
                else
                        cifs_put_tcon(tcon);
        }

        if (!ses_exist)
                goto done;

        /* allocate a dummy tcon struct used for reconnect */
        tcon = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
        if (!tcon) {
                resched = true;
                list_for_each_entry_safe(ses, ses2, &tmp_ses_list, rlist) {
                        list_del_init(&ses->rlist);
                        cifs_put_smb_ses(ses);
                }
                goto done;
        }

        tcon->status = TID_GOOD;
        tcon->retry = false;
        tcon->need_reconnect = false;

        /* now reconnect sessions for necessary channels */
        list_for_each_entry_safe(ses, ses2, &tmp_ses_list, rlist) {
                tcon->ses = ses;
                rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server);
                if (rc)
                        resched = true;
                list_del_init(&ses->rlist);
                cifs_put_smb_ses(ses);
        }
        kfree(tcon);

done:
        cifs_dbg(FYI, "Reconnecting tcons and channels finished\n");
        if (resched)
                queue_delayed_work(cifsiod_wq, &server->reconnect, 2 * HZ);
        mutex_unlock(&pserver->reconnect_mutex);

        /* now we can safely release srv struct */
        if (tcon_exist || ses_exist)
                cifs_put_tcp_session(server, 1);
}

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

        cifs_dbg(FYI, "In echo request for conn_id %lld\n", server->conn_id);

        spin_lock(&server->srv_lock);
        if (server->ops->need_neg &&
            server->ops->need_neg(server)) {
                spin_unlock(&server->srv_lock);
                /* No need to send echo on newly established connections */
                mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
                return rc;
        }
        spin_unlock(&server->srv_lock);

        rc = smb2_plain_req_init(SMB2_ECHO, NULL, server,
                                 (void **)&req, &total_len);
        if (rc)
                return rc;

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

        iov[0].iov_len = total_len;
        iov[0].iov_base = (char *)req;

        rc = cifs_call_async(server, &rqst, NULL, smb2_echo_callback, NULL,
                             server, CIFS_ECHO_OP, NULL);
        if (rc)
                cifs_dbg(FYI, "Echo request failed: %d\n", rc);

        cifs_small_buf_release(req);
        return rc;
}

void
SMB2_flush_free(struct smb_rqst *rqst)
{
        if (rqst && rqst->rq_iov)
                cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
}

int
SMB2_flush_init(const unsigned int xid, struct smb_rqst *rqst,
                struct cifs_tcon *tcon, struct TCP_Server_Info *server,
                u64 persistent_fid, u64 volatile_fid)
{
        struct smb2_flush_req *req;
        struct kvec *iov = rqst->rq_iov;
        unsigned int total_len;
        int rc;

        rc = smb2_plain_req_init(SMB2_FLUSH, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

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

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        return 0;
}

int
SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
           u64 volatile_fid)
{
        struct cifs_ses *ses = tcon->ses;
        struct smb_rqst rqst;
        struct kvec iov[1];
        struct kvec rsp_iov = {NULL, 0};
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        int resp_buftype = CIFS_NO_BUFFER;
        int flags = 0;
        int rc = 0;

        cifs_dbg(FYI, "flush\n");
        if (!ses || !(ses->server))
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = SMB2_flush_init(xid, &rqst, tcon, server,
                             persistent_fid, volatile_fid);
        if (rc)
                goto flush_exit;

        trace_smb3_flush_enter(xid, persistent_fid, tcon->tid, ses->Suid);
        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);

        if (rc != 0) {
                cifs_stats_fail_inc(tcon, SMB2_FLUSH_HE);
                trace_smb3_flush_err(xid, persistent_fid, tcon->tid, ses->Suid,
                                     rc);
        } else
                trace_smb3_flush_done(xid, persistent_fid, tcon->tid,
                                      ses->Suid);

 flush_exit:
        SMB2_flush_free(&rqst);
        free_rsp_buf(resp_buftype, rsp_iov.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(void **buf, unsigned int *total_len,
        struct cifs_io_parms *io_parms, struct cifs_readdata *rdata,
        unsigned int remaining_bytes, int request_type)
{
        int rc = -EACCES;
        struct smb2_read_req *req = NULL;
        struct smb2_hdr *shdr;
        struct TCP_Server_Info *server = io_parms->server;

        rc = smb2_plain_req_init(SMB2_READ, io_parms->tcon, server,
                                 (void **) &req, total_len);
        if (rc)
                return rc;

        if (server == NULL)
                return -ECONNABORTED;

        shdr = &req->hdr;
        shdr->Id.SyncId.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);

        trace_smb3_read_enter(0 /* xid */,
                        io_parms->persistent_fid,
                        io_parms->tcon->tid, io_parms->tcon->ses->Suid,
                        io_parms->offset, io_parms->length);
#ifdef CONFIG_CIFS_SMB_DIRECT
        /*
         * If we want to do a RDMA write, fill in and append
         * smbd_buffer_descriptor_v1 to the end of read request
         */
        if (server->rdma && rdata && !server->sign &&
                rdata->bytes >= server->smbd_conn->rdma_readwrite_threshold) {

                struct smbd_buffer_descriptor_v1 *v1;
                bool need_invalidate = server->dialect == SMB30_PROT_ID;

                rdata->mr = smbd_register_mr(
                                server->smbd_conn, rdata->pages,
                                rdata->nr_pages, rdata->page_offset,
                                rdata->tailsz, true, need_invalidate);
                if (!rdata->mr)
                        return -EAGAIN;

                req->Channel = SMB2_CHANNEL_RDMA_V1_INVALIDATE;
                if (need_invalidate)
                        req->Channel = SMB2_CHANNEL_RDMA_V1;
                req->ReadChannelInfoOffset =
                        cpu_to_le16(offsetof(struct smb2_read_req, Buffer));
                req->ReadChannelInfoLength =
                        cpu_to_le16(sizeof(struct smbd_buffer_descriptor_v1));
                v1 = (struct smbd_buffer_descriptor_v1 *) &req->Buffer[0];
                v1->offset = cpu_to_le64(rdata->mr->mr->iova);
                v1->token = cpu_to_le32(rdata->mr->mr->rkey);
                v1->length = cpu_to_le32(rdata->mr->mr->length);

                *total_len += sizeof(*v1) - 1;
        }
#endif
        if (request_type & CHAINED_REQUEST) {
                if (!(request_type & END_OF_CHAIN)) {
                        /* next 8-byte aligned request */
                        *total_len = DIV_ROUND_UP(*total_len, 8) * 8;
                        shdr->NextCommand = cpu_to_le32(*total_len);
                } else /* END_OF_CHAIN */
                        shdr->NextCommand = 0;
                if (request_type & RELATED_REQUEST) {
                        shdr->Flags |= SMB2_FLAGS_RELATED_OPERATIONS;
                        /*
                         * Related requests use info from previous read request
                         * in chain.
                         */
                        shdr->SessionId = cpu_to_le64(0xFFFFFFFFFFFFFFFF);
                        shdr->Id.SyncId.TreeId = cpu_to_le32(0xFFFFFFFF);
                        req->PersistentFileId = (u64)-1;
                        req->VolatileFileId = (u64)-1;
                }
        }
        if (remaining_bytes > io_parms->length)
                req->RemainingBytes = cpu_to_le32(remaining_bytes);
        else
                req->RemainingBytes = 0;

        *buf = req;
        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 = rdata->server;
        struct smb2_hdr *shdr =
                                (struct smb2_hdr *)rdata->iov[0].iov_base;
        struct cifs_credits credits = { .value = 0, .instance = 0 };
        struct smb_rqst rqst = { .rq_iov = &rdata->iov[1],
                                 .rq_nvec = 1,
                                 .rq_pages = rdata->pages,
                                 .rq_offset = rdata->page_offset,
                                 .rq_npages = rdata->nr_pages,
                                 .rq_pagesz = rdata->pagesz,
                                 .rq_tailsz = rdata->tailsz };

        WARN_ONCE(rdata->server != mid->server,
                  "rdata server %p != mid server %p",
                  rdata->server, mid->server);

        cifs_dbg(FYI, "%s: mid=%llu state=%d result=%d bytes=%u\n",
                 __func__, mid->mid, mid->mid_state, rdata->result,
                 rdata->bytes);

        switch (mid->mid_state) {
        case MID_RESPONSE_RECEIVED:
                credits.value = le16_to_cpu(shdr->CreditRequest);
                credits.instance = server->reconnect_instance;
                /* result already set, check signature */
                if (server->sign && !mid->decrypted) {
                        int rc;

                        rc = smb2_verify_signature(&rqst, server);
                        if (rc)
                                cifs_tcon_dbg(VFS, "SMB signature verification returned error = %d\n",
                                         rc);
                }
                /* FIXME: should this be counted toward the initiating task? */
                task_io_account_read(rdata->got_bytes);
                cifs_stats_bytes_read(tcon, rdata->got_bytes);
                break;
        case MID_REQUEST_SUBMITTED:
        case MID_RETRY_NEEDED:
                rdata->result = -EAGAIN;
                if (server->sign && rdata->got_bytes)
                        /* reset bytes number since we can not check a sign */
                        rdata->got_bytes = 0;
                /* FIXME: should this be counted toward the initiating task? */
                task_io_account_read(rdata->got_bytes);
                cifs_stats_bytes_read(tcon, rdata->got_bytes);
                break;
        case MID_RESPONSE_MALFORMED:
                credits.value = le16_to_cpu(shdr->CreditRequest);
                credits.instance = server->reconnect_instance;
                fallthrough;
        default:
                rdata->result = -EIO;
        }
#ifdef CONFIG_CIFS_SMB_DIRECT
        /*
         * If this rdata has a memmory registered, the MR can be freed
         * MR needs to be freed as soon as I/O finishes to prevent deadlock
         * because they have limited number and are used for future I/Os
         */
        if (rdata->mr) {
                smbd_deregister_mr(rdata->mr);
                rdata->mr = NULL;
        }
#endif
        if (rdata->result && rdata->result != -ENODATA) {
                cifs_stats_fail_inc(tcon, SMB2_READ_HE);
                trace_smb3_read_err(0 /* xid */,
                                    rdata->cfile->fid.persistent_fid,
                                    tcon->tid, tcon->ses->Suid, rdata->offset,
                                    rdata->bytes, rdata->result);
        } else
                trace_smb3_read_done(0 /* xid */,
                                     rdata->cfile->fid.persistent_fid,
                                     tcon->tid, tcon->ses->Suid,
                                     rdata->offset, rdata->got_bytes);

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

/* smb2_async_readv - send an async read, and set up mid to handle result */
int
smb2_async_readv(struct cifs_readdata *rdata)
{
        int rc, flags = 0;
        char *buf;
        struct smb2_hdr *shdr;
        struct cifs_io_parms io_parms;
        struct smb_rqst rqst = { .rq_iov = rdata->iov,
                                 .rq_nvec = 1 };
        struct TCP_Server_Info *server;
        struct cifs_tcon *tcon = tlink_tcon(rdata->cfile->tlink);
        unsigned int total_len;

        cifs_dbg(FYI, "%s: offset=%llu bytes=%u\n",
                 __func__, rdata->offset, rdata->bytes);

        if (!rdata->server)
                rdata->server = cifs_pick_channel(tcon->ses);

        io_parms.tcon = tlink_tcon(rdata->cfile->tlink);
        io_parms.server = server = rdata->server;
        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(
                (void **) &buf, &total_len, &io_parms, rdata, 0, 0);
        if (rc)
                return rc;

        if (smb3_encryption_required(io_parms.tcon))
                flags |= CIFS_TRANSFORM_REQ;

        rdata->iov[0].iov_base = buf;
        rdata->iov[0].iov_len = total_len;

        shdr = (struct smb2_hdr *)buf;

        if (rdata->credits.value > 0) {
                shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
                                                SMB2_MAX_BUFFER_SIZE));
                shdr->CreditRequest = cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 8);

                rc = adjust_credits(server, &rdata->credits, rdata->bytes);
                if (rc)
                        goto async_readv_out;

                flags |= CIFS_HAS_CREDITS;
        }

        kref_get(&rdata->refcount);
        rc = cifs_call_async(server, &rqst,
                             cifs_readv_receive, smb2_readv_callback,
                             smb3_handle_read_data, rdata, flags,
                             &rdata->credits);
        if (rc) {
                kref_put(&rdata->refcount, cifs_readdata_release);
                cifs_stats_fail_inc(io_parms.tcon, SMB2_READ_HE);
                trace_smb3_read_err(0 /* xid */, io_parms.persistent_fid,
                                    io_parms.tcon->tid,
                                    io_parms.tcon->ses->Suid,
                                    io_parms.offset, io_parms.length, rc);
        }

async_readv_out:
        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)
{
        struct smb_rqst rqst;
        int resp_buftype, rc;
        struct smb2_read_req *req = NULL;
        struct smb2_read_rsp *rsp = NULL;
        struct kvec iov[1];
        struct kvec rsp_iov;
        unsigned int total_len;
        int flags = CIFS_LOG_ERROR;
        struct cifs_ses *ses = io_parms->tcon->ses;

        if (!io_parms->server)
                io_parms->server = cifs_pick_channel(io_parms->tcon->ses);

        *nbytes = 0;
        rc = smb2_new_read_req((void **)&req, &total_len, io_parms, NULL, 0, 0);
        if (rc)
                return rc;

        if (smb3_encryption_required(io_parms->tcon))
                flags |= CIFS_TRANSFORM_REQ;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, io_parms->server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        rsp = (struct smb2_read_rsp *)rsp_iov.iov_base;

        if (rc) {
                if (rc != -ENODATA) {
                        cifs_stats_fail_inc(io_parms->tcon, SMB2_READ_HE);
                        cifs_dbg(VFS, "Send error in read = %d\n", rc);
                        trace_smb3_read_err(xid,
                                            req->PersistentFileId,
                                            io_parms->tcon->tid, ses->Suid,
                                            io_parms->offset, io_parms->length,
                                            rc);
                } else
                        trace_smb3_read_done(xid, req->PersistentFileId, io_parms->tcon->tid,
                                             ses->Suid, io_parms->offset, 0);
                free_rsp_buf(resp_buftype, rsp_iov.iov_base);
                cifs_small_buf_release(req);
                return rc == -ENODATA ? 0 : rc;
        } else
                trace_smb3_read_done(xid,
                                    req->PersistentFileId,
                                    io_parms->tcon->tid, ses->Suid,
                                    io_parms->offset, io_parms->length);

        cifs_small_buf_release(req);

        *nbytes = le32_to_cpu(rsp->DataLength);
        if ((*nbytes > CIFS_MAX_MSGSIZE) ||
            (*nbytes > io_parms->length)) {
                cifs_dbg(FYI, "bad length %d for count %d\n",
                         *nbytes, io_parms->length);
                rc = -EIO;
                *nbytes = 0;
        }

        if (*buf) {
                memcpy(*buf, (char *)rsp + rsp->DataOffset, *nbytes);
                free_rsp_buf(resp_buftype, rsp_iov.iov_base);
        } else if (resp_buftype != CIFS_NO_BUFFER) {
                *buf = rsp_iov.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);
        struct TCP_Server_Info *server = wdata->server;
        unsigned int written;
        struct smb2_write_rsp *rsp = (struct smb2_write_rsp *)mid->resp_buf;
        struct cifs_credits credits = { .value = 0, .instance = 0 };

        WARN_ONCE(wdata->server != mid->server,
                  "wdata server %p != mid server %p",
                  wdata->server, mid->server);

        switch (mid->mid_state) {
        case MID_RESPONSE_RECEIVED:
                credits.value = le16_to_cpu(rsp->hdr.CreditRequest);
                credits.instance = server->reconnect_instance;
                wdata->result = smb2_check_receive(mid, 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;
        case MID_RESPONSE_MALFORMED:
                credits.value = le16_to_cpu(rsp->hdr.CreditRequest);
                credits.instance = server->reconnect_instance;
                fallthrough;
        default:
                wdata->result = -EIO;
                break;
        }
#ifdef CONFIG_CIFS_SMB_DIRECT
        /*
         * If this wdata has a memory registered, the MR can be freed
         * The number of MRs available is limited, it's important to recover
         * used MR as soon as I/O is finished. Hold MR longer in the later
         * I/O process can possibly result in I/O deadlock due to lack of MR
         * to send request on I/O retry
         */
        if (wdata->mr) {
                smbd_deregister_mr(wdata->mr);
                wdata->mr = NULL;
        }
#endif
        if (wdata->result) {
                cifs_stats_fail_inc(tcon, SMB2_WRITE_HE);
                trace_smb3_write_err(0 /* no xid */,
                                     wdata->cfile->fid.persistent_fid,
                                     tcon->tid, tcon->ses->Suid, wdata->offset,
                                     wdata->bytes, wdata->result);
                if (wdata->result == -ENOSPC)
                        pr_warn_once("Out of space writing to %s\n",
                                     tcon->treeName);
        } else
                trace_smb3_write_done(0 /* no xid */,
                                      wdata->cfile->fid.persistent_fid,
                                      tcon->tid, tcon->ses->Suid,
                                      wdata->offset, wdata->bytes);

        queue_work(cifsiod_wq, &wdata->work);
        release_mid(mid);
        add_credits(server, &credits, 0);
}

/* smb2_async_writev - send an async write, and set up mid to handle result */
int
smb2_async_writev(struct cifs_writedata *wdata,
                  void (*release)(struct kref *kref))
{
        int rc = -EACCES, flags = 0;
        struct smb2_write_req *req = NULL;
        struct smb2_hdr *shdr;
        struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
        struct TCP_Server_Info *server = wdata->server;
        struct kvec iov[1];
        struct smb_rqst rqst = { };
        unsigned int total_len;

        if (!wdata->server)
                server = wdata->server = cifs_pick_channel(tcon->ses);

        rc = smb2_plain_req_init(SMB2_WRITE, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        shdr = (struct smb2_hdr *)req;
        shdr->Id.SyncId.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);
        req->DataOffset = cpu_to_le16(
                                offsetof(struct smb2_write_req, Buffer));
        req->RemainingBytes = 0;

        trace_smb3_write_enter(0 /* xid */, wdata->cfile->fid.persistent_fid,
                tcon->tid, tcon->ses->Suid, wdata->offset, wdata->bytes);
#ifdef CONFIG_CIFS_SMB_DIRECT
        /*
         * If we want to do a server RDMA read, fill in and append
         * smbd_buffer_descriptor_v1 to the end of write request
         */
        if (server->rdma && !server->sign && wdata->bytes >=
                server->smbd_conn->rdma_readwrite_threshold) {

                struct smbd_buffer_descriptor_v1 *v1;
                bool need_invalidate = server->dialect == SMB30_PROT_ID;

                wdata->mr = smbd_register_mr(
                                server->smbd_conn, wdata->pages,
                                wdata->nr_pages, wdata->page_offset,
                                wdata->tailsz, false, need_invalidate);
                if (!wdata->mr) {
                        rc = -EAGAIN;
                        goto async_writev_out;
                }
                req->Length = 0;
                req->DataOffset = 0;
                if (wdata->nr_pages > 1)
                        req->RemainingBytes =
                                cpu_to_le32(
                                        (wdata->nr_pages - 1) * wdata->pagesz -
                                        wdata->page_offset + wdata->tailsz
                                );
                else
                        req->RemainingBytes = cpu_to_le32(wdata->tailsz);
                req->Channel = SMB2_CHANNEL_RDMA_V1_INVALIDATE;
                if (need_invalidate)
                        req->Channel = SMB2_CHANNEL_RDMA_V1;
                req->WriteChannelInfoOffset =
                        cpu_to_le16(offsetof(struct smb2_write_req, Buffer));
                req->WriteChannelInfoLength =
                        cpu_to_le16(sizeof(struct smbd_buffer_descriptor_v1));
                v1 = (struct smbd_buffer_descriptor_v1 *) &req->Buffer[0];
                v1->offset = cpu_to_le64(wdata->mr->mr->iova);
                v1->token = cpu_to_le32(wdata->mr->mr->rkey);
                v1->length = cpu_to_le32(wdata->mr->mr->length);
        }
#endif
        iov[0].iov_len = total_len - 1;
        iov[0].iov_base = (char *)req;

        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;
        rqst.rq_pages = wdata->pages;
        rqst.rq_offset = wdata->page_offset;
        rqst.rq_npages = wdata->nr_pages;
        rqst.rq_pagesz = wdata->pagesz;
        rqst.rq_tailsz = wdata->tailsz;
#ifdef CONFIG_CIFS_SMB_DIRECT
        if (wdata->mr) {
                iov[0].iov_len += sizeof(struct smbd_buffer_descriptor_v1);
                rqst.rq_npages = 0;
        }
#endif
        cifs_dbg(FYI, "async write at %llu %u bytes\n",
                 wdata->offset, wdata->bytes);

#ifdef CONFIG_CIFS_SMB_DIRECT
        /* For RDMA read, I/O size is in RemainingBytes not in Length */
        if (!wdata->mr)
                req->Length = cpu_to_le32(wdata->bytes);
#else
        req->Length = cpu_to_le32(wdata->bytes);
#endif

        if (wdata->credits.value > 0) {
                shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(wdata->bytes,
                                                    SMB2_MAX_BUFFER_SIZE));
                shdr->CreditRequest = cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 8);

                rc = adjust_credits(server, &wdata->credits, wdata->bytes);
                if (rc)
                        goto async_writev_out;

                flags |= CIFS_HAS_CREDITS;
        }

        kref_get(&wdata->refcount);
        rc = cifs_call_async(server, &rqst, NULL, smb2_writev_callback, NULL,
                             wdata, flags, &wdata->credits);

        if (rc) {
                trace_smb3_write_err(0 /* no xid */,
                                     req->PersistentFileId,
                                     tcon->tid, tcon->ses->Suid, wdata->offset,
                                     wdata->bytes, rc);
                kref_put(&wdata->refcount, 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)
{
        struct smb_rqst rqst;
        int rc = 0;
        struct smb2_write_req *req = NULL;
        struct smb2_write_rsp *rsp = NULL;
        int resp_buftype;
        struct kvec rsp_iov;
        int flags = 0;
        unsigned int total_len;
        struct TCP_Server_Info *server;

        *nbytes = 0;

        if (n_vec < 1)
                return rc;

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

        rc = smb2_plain_req_init(SMB2_WRITE, io_parms->tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        if (smb3_encryption_required(io_parms->tcon))
                flags |= CIFS_TRANSFORM_REQ;

        req->hdr.Id.SyncId.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);
        req->DataOffset = cpu_to_le16(
                                offsetof(struct smb2_write_req, Buffer));
        req->RemainingBytes = 0;

        trace_smb3_write_enter(xid, io_parms->persistent_fid,
                io_parms->tcon->tid, io_parms->tcon->ses->Suid,
                io_parms->offset, io_parms->length);

        iov[0].iov_base = (char *)req;
        /* 1 for Buffer */
        iov[0].iov_len = total_len - 1;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = n_vec + 1;

        rc = cifs_send_recv(xid, io_parms->tcon->ses, server,
                            &rqst,
                            &resp_buftype, flags, &rsp_iov);
        rsp = (struct smb2_write_rsp *)rsp_iov.iov_base;

        if (rc) {
                trace_smb3_write_err(xid,
                                     req->PersistentFileId,
                                     io_parms->tcon->tid,
                                     io_parms->tcon->ses->Suid,
                                     io_parms->offset, io_parms->length, rc);
                cifs_stats_fail_inc(io_parms->tcon, SMB2_WRITE_HE);
                cifs_dbg(VFS, "Send error in write = %d\n", rc);
        } else {
                *nbytes = le32_to_cpu(rsp->DataLength);
                trace_smb3_write_done(xid,
                                      req->PersistentFileId,
                                      io_parms->tcon->tid,
                                      io_parms->tcon->ses->Suid,
                                      io_parms->offset, *nbytes);
        }

        cifs_small_buf_release(req);
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

int posix_info_sid_size(const void *beg, const void *end)
{
        size_t subauth;
        int total;

        if (beg + 1 > end)
                return -1;

        subauth = *(u8 *)(beg+1);
        if (subauth < 1 || subauth > 15)
                return -1;

        total = 1 + 1 + 6 + 4*subauth;
        if (beg + total > end)
                return -1;

        return total;
}

int posix_info_parse(const void *beg, const void *end,
                     struct smb2_posix_info_parsed *out)

{
        int total_len = 0;
        int owner_len, group_len;
        int name_len;
        const void *owner_sid;
        const void *group_sid;
        const void *name;

        /* if no end bound given, assume payload to be correct */
        if (!end) {
                const struct smb2_posix_info *p = beg;

                end = beg + le32_to_cpu(p->NextEntryOffset);
                /* last element will have a 0 offset, pick a sensible bound */
                if (end == beg)
                        end += 0xFFFF;
        }

        /* check base buf */
        if (beg + sizeof(struct smb2_posix_info) > end)
                return -1;
        total_len = sizeof(struct smb2_posix_info);

        /* check owner sid */
        owner_sid = beg + total_len;
        owner_len = posix_info_sid_size(owner_sid, end);
        if (owner_len < 0)
                return -1;
        total_len += owner_len;

        /* check group sid */
        group_sid = beg + total_len;
        group_len = posix_info_sid_size(group_sid, end);
        if (group_len < 0)
                return -1;
        total_len += group_len;

        /* check name len */
        if (beg + total_len + 4 > end)
                return -1;
        name_len = le32_to_cpu(*(__le32 *)(beg + total_len));
        if (name_len < 1 || name_len > 0xFFFF)
                return -1;
        total_len += 4;

        /* check name */
        name = beg + total_len;
        if (name + name_len > end)
                return -1;
        total_len += name_len;

        if (out) {
                out->base = beg;
                out->size = total_len;
                out->name_len = name_len;
                out->name = name;
                memcpy(&out->owner, owner_sid, owner_len);
                memcpy(&out->group, group_sid, group_len);
        }
        return total_len;
}

static int posix_info_extra_size(const void *beg, const void *end)
{
        int len = posix_info_parse(beg, end, NULL);

        if (len < 0)
                return -1;
        return len - sizeof(struct smb2_posix_info);
}

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

        if (bufstart == NULL)
                return 0;

        entryptr = bufstart;

        while (1) {
                if (entryptr + next_offset < entryptr ||
                    entryptr + next_offset > end_of_buf ||
                    entryptr + next_offset + size > end_of_buf) {
                        cifs_dbg(VFS, "malformed search entry would overflow\n");
                        break;
                }

                entryptr = entryptr + next_offset;
                dir_info = (FILE_DIRECTORY_INFO *)entryptr;

                if (infotype == SMB_FIND_FILE_POSIX_INFO)
                        len = posix_info_extra_size(entryptr, end_of_buf);
                else
                        len = le32_to_cpu(dir_info->FileNameLength);

                if (len < 0 ||
                    entryptr + len < entryptr ||
                    entryptr + len > end_of_buf ||
                    entryptr + len + size > end_of_buf) {
                        cifs_dbg(VFS, "directory entry name would overflow frame end of buf %p\n",
                                 end_of_buf);
                        break;
                }

                *lastentry = entryptr;
                entrycount++;

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

        return entrycount;
}

/*
 * Readdir/FindFirst
 */
int SMB2_query_directory_init(const unsigned int xid,
                              struct cifs_tcon *tcon,
                              struct TCP_Server_Info *server,
                              struct smb_rqst *rqst,
                              u64 persistent_fid, u64 volatile_fid,
                              int index, int info_level)
{
        struct smb2_query_directory_req *req;
        unsigned char *bufptr;
        __le16 asteriks = cpu_to_le16('*');
        unsigned int output_size = CIFSMaxBufSize -
                MAX_SMB2_CREATE_RESPONSE_SIZE -
                MAX_SMB2_CLOSE_RESPONSE_SIZE;
        unsigned int total_len;
        struct kvec *iov = rqst->rq_iov;
        int len, rc;

        rc = smb2_plain_req_init(SMB2_QUERY_DIRECTORY, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        switch (info_level) {
        case SMB_FIND_FILE_DIRECTORY_INFO:
                req->FileInformationClass = FILE_DIRECTORY_INFORMATION;
                break;
        case SMB_FIND_FILE_ID_FULL_DIR_INFO:
                req->FileInformationClass = FILEID_FULL_DIRECTORY_INFORMATION;
                break;
        case SMB_FIND_FILE_POSIX_INFO:
                req->FileInformationClass = SMB_FIND_FILE_POSIX_INFO;
                break;
        default:
                cifs_tcon_dbg(VFS, "info level %u isn't supported\n",
                        info_level);
                return -EINVAL;
        }

        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);
        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;
        /* 1 for Buffer */
        iov[0].iov_len = total_len - 1;

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

        trace_smb3_query_dir_enter(xid, persistent_fid, tcon->tid,
                        tcon->ses->Suid, index, output_size);

        return 0;
}

void SMB2_query_directory_free(struct smb_rqst *rqst)
{
        if (rqst && rqst->rq_iov) {
                cifs_small_buf_release(rqst->rq_iov[0].iov_base); /* request */
        }
}

int
smb2_parse_query_directory(struct cifs_tcon *tcon,
                           struct kvec *rsp_iov,
                           int resp_buftype,
                           struct cifs_search_info *srch_inf)
{
        struct smb2_query_directory_rsp *rsp;
        size_t info_buf_size;
        char *end_of_smb;
        int rc;

        rsp = (struct smb2_query_directory_rsp *)rsp_iov->iov_base;

        switch (srch_inf->info_level) {
        case SMB_FIND_FILE_DIRECTORY_INFO:
                info_buf_size = sizeof(FILE_DIRECTORY_INFO) - 1;
                break;
        case SMB_FIND_FILE_ID_FULL_DIR_INFO:
                info_buf_size = sizeof(SEARCH_ID_FULL_DIR_INFO) - 1;
                break;
        case SMB_FIND_FILE_POSIX_INFO:
                /* note that posix payload are variable size */
                info_buf_size = sizeof(struct smb2_posix_info);
                break;
        default:
                cifs_tcon_dbg(VFS, "info level %u isn't supported\n",
                         srch_inf->info_level);
                return -EINVAL;
        }

        rc = smb2_validate_iov(le16_to_cpu(rsp->OutputBufferOffset),
                               le32_to_cpu(rsp->OutputBufferLength), rsp_iov,
                               info_buf_size);
        if (rc) {
                cifs_tcon_dbg(VFS, "bad info payload");
                return rc;
        }

        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 =
                (char *)rsp + le16_to_cpu(rsp->OutputBufferOffset);
        end_of_smb = rsp_iov->iov_len + (char *)rsp;

        srch_inf->entries_in_buffer = num_entries(
                srch_inf->info_level,
                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;
        cifs_dbg(FYI, "num entries %d last_index %lld srch start %p srch end %p\n",
                 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
                cifs_tcon_dbg(VFS, "Invalid search buffer type\n");

        return 0;
}

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 smb_rqst rqst;
        struct kvec iov[SMB2_QUERY_DIRECTORY_IOV_SIZE];
        struct smb2_query_directory_rsp *rsp = NULL;
        int resp_buftype = CIFS_NO_BUFFER;
        struct kvec rsp_iov;
        int rc = 0;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        int flags = 0;

        if (!ses || !(ses->server))
                return -EIO;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        memset(&iov, 0, sizeof(iov));
        rqst.rq_iov = iov;
        rqst.rq_nvec = SMB2_QUERY_DIRECTORY_IOV_SIZE;

        rc = SMB2_query_directory_init(xid, tcon, server,
                                       &rqst, persistent_fid,
                                       volatile_fid, index,
                                       srch_inf->info_level);
        if (rc)
                goto qdir_exit;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        rsp = (struct smb2_query_directory_rsp *)rsp_iov.iov_base;

        if (rc) {
                if (rc == -ENODATA &&
                    rsp->hdr.Status == STATUS_NO_MORE_FILES) {
                        trace_smb3_query_dir_done(xid, persistent_fid,
                                tcon->tid, tcon->ses->Suid, index, 0);
                        srch_inf->endOfSearch = true;
                        rc = 0;
                } else {
                        trace_smb3_query_dir_err(xid, persistent_fid, tcon->tid,
                                tcon->ses->Suid, index, 0, rc);
                        cifs_stats_fail_inc(tcon, SMB2_QUERY_DIRECTORY_HE);
                }
                goto qdir_exit;
        }

        rc = smb2_parse_query_directory(tcon, &rsp_iov, resp_buftype,
                                        srch_inf);
        if (rc) {
                trace_smb3_query_dir_err(xid, persistent_fid, tcon->tid,
                        tcon->ses->Suid, index, 0, rc);
                goto qdir_exit;
        }
        resp_buftype = CIFS_NO_BUFFER;

        trace_smb3_query_dir_done(xid, persistent_fid, tcon->tid,
                        tcon->ses->Suid, index, srch_inf->entries_in_buffer);

qdir_exit:
        SMB2_query_directory_free(&rqst);
        free_rsp_buf(resp_buftype, rsp);
        return rc;
}

int
SMB2_set_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
                   struct smb_rqst *rqst,
                   u64 persistent_fid, u64 volatile_fid, u32 pid,
                   u8 info_class, u8 info_type, u32 additional_info,
                   void **data, unsigned int *size)
{
        struct smb2_set_info_req *req;
        struct kvec *iov = rqst->rq_iov;
        unsigned int i, total_len;
        int rc;

        rc = smb2_plain_req_init(SMB2_SET_INFO, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        req->hdr.Id.SyncId.ProcessId = cpu_to_le32(pid);
        req->InfoType = info_type;
        req->FileInfoClass = info_class;
        req->PersistentFileId = persistent_fid;
        req->VolatileFileId = volatile_fid;
        req->AdditionalInformation = cpu_to_le32(additional_info);

        req->BufferOffset =
                        cpu_to_le16(sizeof(struct smb2_set_info_req) - 1);
        req->BufferLength = cpu_to_le32(*size);

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

        iov[0].iov_base = (char *)req;
        /* 1 for Buffer */
        iov[0].iov_len = total_len - 1;

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

        return 0;
}

void
SMB2_set_info_free(struct smb_rqst *rqst)
{
        if (rqst && rqst->rq_iov)
                cifs_buf_release(rqst->rq_iov[0].iov_base); /* request */
}

static int
send_set_info(const unsigned int xid, struct cifs_tcon *tcon,
               u64 persistent_fid, u64 volatile_fid, u32 pid, u8 info_class,
               u8 info_type, u32 additional_info, unsigned int num,
                void **data, unsigned int *size)
{
        struct smb_rqst rqst;
        struct smb2_set_info_rsp *rsp = NULL;
        struct kvec *iov;
        struct kvec rsp_iov;
        int rc = 0;
        int resp_buftype;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        int flags = 0;

        if (!ses || !server)
                return -EIO;

        if (!num)
                return -EINVAL;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

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

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = num;

        rc = SMB2_set_info_init(tcon, server,
                                &rqst, persistent_fid, volatile_fid, pid,
                                info_class, info_type, additional_info,
                                data, size);
        if (rc) {
                kfree(iov);
                return rc;
        }


        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags,
                            &rsp_iov);
        SMB2_set_info_free(&rqst);
        rsp = (struct smb2_set_info_rsp *)rsp_iov.iov_base;

        if (rc != 0) {
                cifs_stats_fail_inc(tcon, SMB2_SET_INFO_HE);
                trace_smb3_set_info_err(xid, persistent_fid, tcon->tid,
                                ses->Suid, info_class, (__u32)info_type, rc);
        }

        free_rsp_buf(resp_buftype, rsp);
        kfree(iov);
        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);

        trace_smb3_set_eof(xid, persistent_fid, tcon->tid, tcon->ses->Suid, le64_to_cpu(*eof));

        return send_set_info(xid, tcon, persistent_fid, volatile_fid,
                        pid, FILE_END_OF_FILE_INFORMATION, SMB2_O_INFO_FILE,
                        0, 1, &data, &size);
}

int
SMB2_set_acl(const unsigned int xid, struct cifs_tcon *tcon,
                u64 persistent_fid, u64 volatile_fid,
                struct cifs_ntsd *pnntsd, int pacllen, int aclflag)
{
        return send_set_info(xid, tcon, persistent_fid, volatile_fid,
                        current->tgid, 0, SMB2_O_INFO_SECURITY, aclflag,
                        1, (void **)&pnntsd, &pacllen);
}

int
SMB2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
            u64 persistent_fid, u64 volatile_fid,
            struct smb2_file_full_ea_info *buf, int len)
{
        return send_set_info(xid, tcon, persistent_fid, volatile_fid,
                current->tgid, FILE_FULL_EA_INFORMATION, SMB2_O_INFO_FILE,
                0, 1, (void **)&buf, &len);
}

int
SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
                  const u64 persistent_fid, const u64 volatile_fid,
                  __u8 oplock_level)
{
        struct smb_rqst rqst;
        int rc;
        struct smb2_oplock_break *req = NULL;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        int flags = CIFS_OBREAK_OP;
        unsigned int total_len;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int resp_buf_type;

        cifs_dbg(FYI, "SMB2_oplock_break\n");
        rc = smb2_plain_req_init(SMB2_OPLOCK_BREAK, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

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

        flags |= CIFS_NO_RSP_BUF;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buf_type, flags, &rsp_iov);
        cifs_small_buf_release(req);

        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_OPLOCK_BREAK_HE);
                cifs_dbg(FYI, "Send error in Oplock Break = %d\n", rc);
        }

        return rc;
}

void
smb2_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  = kst->f_bavail =
                        le64_to_cpu(pfs_inf->CallerAvailableAllocationUnits);
        return;
}

static void
copy_posix_fs_info_to_kstatfs(FILE_SYSTEM_POSIX_INFO *response_data,
                        struct kstatfs *kst)
{
        kst->f_bsize = le32_to_cpu(response_data->BlockSize);
        kst->f_blocks = le64_to_cpu(response_data->TotalBlocks);
        kst->f_bfree =  le64_to_cpu(response_data->BlocksAvail);
        if (response_data->UserBlocksAvail == cpu_to_le64(-1))
                kst->f_bavail = kst->f_bfree;
        else
                kst->f_bavail = le64_to_cpu(response_data->UserBlocksAvail);
        if (response_data->TotalFileNodes != cpu_to_le64(-1))
                kst->f_files = le64_to_cpu(response_data->TotalFileNodes);
        if (response_data->FreeFileNodes != cpu_to_le64(-1))
                kst->f_ffree = le64_to_cpu(response_data->FreeFileNodes);

        return;
}

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

        cifs_dbg(FYI, "Query FSInfo level %d\n", level);

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

        rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

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

        iov->iov_base = (char *)req;
        iov->iov_len = total_len;
        return 0;
}

int
SMB311_posix_qfs_info(const unsigned int xid, struct cifs_tcon *tcon,
              u64 persistent_fid, u64 volatile_fid, struct kstatfs *fsdata)
{
        struct smb_rqst rqst;
        struct smb2_query_info_rsp *rsp = NULL;
        struct kvec iov;
        struct kvec rsp_iov;
        int rc = 0;
        int resp_buftype;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        FILE_SYSTEM_POSIX_INFO *info = NULL;
        int flags = 0;

        rc = build_qfs_info_req(&iov, tcon, server,
                                FS_POSIX_INFORMATION,
                                sizeof(FILE_SYSTEM_POSIX_INFO),
                                persistent_fid, volatile_fid);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = &iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        cifs_small_buf_release(iov.iov_base);
        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
                goto posix_qfsinf_exit;
        }
        rsp = (struct smb2_query_info_rsp *)rsp_iov.iov_base;

        info = (FILE_SYSTEM_POSIX_INFO *)(
                le16_to_cpu(rsp->OutputBufferOffset) + (char *)rsp);
        rc = smb2_validate_iov(le16_to_cpu(rsp->OutputBufferOffset),
                               le32_to_cpu(rsp->OutputBufferLength), &rsp_iov,
                               sizeof(FILE_SYSTEM_POSIX_INFO));
        if (!rc)
                copy_posix_fs_info_to_kstatfs(info, fsdata);

posix_qfsinf_exit:
        free_rsp_buf(resp_buftype, rsp_iov.iov_base);
        return rc;
}

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

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

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = &iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        cifs_small_buf_release(iov.iov_base);
        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
                goto qfsinf_exit;
        }
        rsp = (struct smb2_query_info_rsp *)rsp_iov.iov_base;

        info = (struct smb2_fs_full_size_info *)(
                le16_to_cpu(rsp->OutputBufferOffset) + (char *)rsp);
        rc = smb2_validate_iov(le16_to_cpu(rsp->OutputBufferOffset),
                               le32_to_cpu(rsp->OutputBufferLength), &rsp_iov,
                               sizeof(struct smb2_fs_full_size_info));
        if (!rc)
                smb2_copy_fs_info_to_kstatfs(info, fsdata);

qfsinf_exit:
        free_rsp_buf(resp_buftype, rsp_iov.iov_base);
        return rc;
}

int
SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon,
              u64 persistent_fid, u64 volatile_fid, int level)
{
        struct smb_rqst rqst;
        struct smb2_query_info_rsp *rsp = NULL;
        struct kvec iov;
        struct kvec rsp_iov;
        int rc = 0;
        int resp_buftype, max_len, min_len;
        struct cifs_ses *ses = tcon->ses;
        struct TCP_Server_Info *server = cifs_pick_channel(ses);
        unsigned int rsp_len, offset;
        int flags = 0;

        if (level == FS_DEVICE_INFORMATION) {
                max_len = sizeof(FILE_SYSTEM_DEVICE_INFO);
                min_len = sizeof(FILE_SYSTEM_DEVICE_INFO);
        } else if (level == FS_ATTRIBUTE_INFORMATION) {
                max_len = sizeof(FILE_SYSTEM_ATTRIBUTE_INFO);
                min_len = MIN_FS_ATTR_INFO_SIZE;
        } else if (level == FS_SECTOR_SIZE_INFORMATION) {
                max_len = sizeof(struct smb3_fs_ss_info);
                min_len = sizeof(struct smb3_fs_ss_info);
        } else if (level == FS_VOLUME_INFORMATION) {
                max_len = sizeof(struct smb3_fs_vol_info) + MAX_VOL_LABEL_LEN;
                min_len = sizeof(struct smb3_fs_vol_info);
        } else {
                cifs_dbg(FYI, "Invalid qfsinfo level %d\n", level);
                return -EINVAL;
        }

        rc = build_qfs_info_req(&iov, tcon, server,
                                level, max_len,
                                persistent_fid, volatile_fid);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = &iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buftype, flags, &rsp_iov);
        cifs_small_buf_release(iov.iov_base);
        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
                goto qfsattr_exit;
        }
        rsp = (struct smb2_query_info_rsp *)rsp_iov.iov_base;

        rsp_len = le32_to_cpu(rsp->OutputBufferLength);
        offset = le16_to_cpu(rsp->OutputBufferOffset);
        rc = smb2_validate_iov(offset, rsp_len, &rsp_iov, min_len);
        if (rc)
                goto qfsattr_exit;

        if (level == FS_ATTRIBUTE_INFORMATION)
                memcpy(&tcon->fsAttrInfo, offset
                        + (char *)rsp, min_t(unsigned int,
                        rsp_len, max_len));
        else if (level == FS_DEVICE_INFORMATION)
                memcpy(&tcon->fsDevInfo, offset
                        + (char *)rsp, sizeof(FILE_SYSTEM_DEVICE_INFO));
        else if (level == FS_SECTOR_SIZE_INFORMATION) {
                struct smb3_fs_ss_info *ss_info = (struct smb3_fs_ss_info *)
                        (offset + (char *)rsp);
                tcon->ss_flags = le32_to_cpu(ss_info->Flags);
                tcon->perf_sector_size =
                        le32_to_cpu(ss_info->PhysicalBytesPerSectorForPerf);
        } else if (level == FS_VOLUME_INFORMATION) {
                struct smb3_fs_vol_info *vol_info = (struct smb3_fs_vol_info *)
                        (offset + (char *)rsp);
                tcon->vol_serial_number = vol_info->VolumeSerialNumber;
                tcon->vol_create_time = vol_info->VolumeCreationTime;
        }

qfsattr_exit:
        free_rsp_buf(resp_buftype, rsp_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)
{
        struct smb_rqst rqst;
        int rc = 0;
        struct smb2_lock_req *req = NULL;
        struct kvec iov[2];
        struct kvec rsp_iov;
        int resp_buf_type;
        unsigned int count;
        int flags = CIFS_NO_RSP_BUF;
        unsigned int total_len;
        struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);

        cifs_dbg(FYI, "smb2_lockv num lock %d\n", num_lock);

        rc = smb2_plain_req_init(SMB2_LOCK, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        req->hdr.Id.SyncId.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);

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len - sizeof(struct smb2_lock_element);
        iov[1].iov_base = (char *)buf;
        iov[1].iov_len = count;

        cifs_stats_inc(&tcon->stats.cifs_stats.num_locks);

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 2;

        rc = cifs_send_recv(xid, tcon->ses, server,
                            &rqst, &resp_buf_type, flags,
                            &rsp_iov);
        cifs_small_buf_release(req);
        if (rc) {
                cifs_dbg(FYI, "Send error in smb2_lockv = %d\n", rc);
                cifs_stats_fail_inc(tcon, SMB2_LOCK_HE);
                trace_smb3_lock_err(xid, persist_fid, tcon->tid,
                                    tcon->ses->Suid, rc);
        }

        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)
{
        struct smb_rqst rqst;
        int rc;
        struct smb2_lease_ack *req = NULL;
        struct cifs_ses *ses = tcon->ses;
        int flags = CIFS_OBREAK_OP;
        unsigned int total_len;
        struct kvec iov[1];
        struct kvec rsp_iov;
        int resp_buf_type;
        __u64 *please_key_high;
        __u64 *please_key_low;
        struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);

        cifs_dbg(FYI, "SMB2_lease_break\n");
        rc = smb2_plain_req_init(SMB2_OPLOCK_BREAK, tcon, server,
                                 (void **) &req, &total_len);
        if (rc)
                return rc;

        if (smb3_encryption_required(tcon))
                flags |= CIFS_TRANSFORM_REQ;

        req->hdr.CreditRequest = cpu_to_le16(1);
        req->StructureSize = cpu_to_le16(36);
        total_len += 12;

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

        flags |= CIFS_NO_RSP_BUF;

        iov[0].iov_base = (char *)req;
        iov[0].iov_len = total_len;

        memset(&rqst, 0, sizeof(struct smb_rqst));
        rqst.rq_iov = iov;
        rqst.rq_nvec = 1;

        rc = cifs_send_recv(xid, ses, server,
                            &rqst, &resp_buf_type, flags, &rsp_iov);
        cifs_small_buf_release(req);

        please_key_low = (__u64 *)lease_key;
        please_key_high = (__u64 *)(lease_key+8);
        if (rc) {
                cifs_stats_fail_inc(tcon, SMB2_OPLOCK_BREAK_HE);
                trace_smb3_lease_err(le32_to_cpu(lease_state), tcon->tid,
                        ses->Suid, *please_key_low, *please_key_high, rc);
                cifs_dbg(FYI, "Send error in Lease Break = %d\n", rc);
        } else
                trace_smb3_lease_done(le32_to_cpu(lease_state), tcon->tid,
                        ses->Suid, *please_key_low, *please_key_high);

        return rc;
}