/*
 *  SMB2 version specific operations
 *
 *  Copyright (c) 2012, Jeff Layton <jlayton@redhat.com>
 *
 *  This library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License v2 as published
 *  by the Free Software Foundation.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *  the GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/pagemap.h>
#include <linux/vfs.h>
#include <linux/falloc.h>
#include <linux/scatterlist.h>
#include <linux/uuid.h>
#include <crypto/aead.h>
#include "cifsglob.h"
#include "smb2pdu.h"
#include "smb2proto.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
#include "smb2status.h"
#include "smb2glob.h"
#include "cifs_ioctl.h"
#include "smbdirect.h"

static int
change_conf(struct TCP_Server_Info *server)
{
        server->credits += server->echo_credits + server->oplock_credits;
        server->oplock_credits = server->echo_credits = 0;
        switch (server->credits) {
        case 0:
                return -1;
        case 1:
                server->echoes = false;
                server->oplocks = false;
                cifs_dbg(VFS, "disabling echoes and oplocks\n");
                break;
        case 2:
                server->echoes = true;
                server->oplocks = false;
                server->echo_credits = 1;
                cifs_dbg(FYI, "disabling oplocks\n");
                break;
        default:
                server->echoes = true;
                if (enable_oplocks) {
                        server->oplocks = true;
                        server->oplock_credits = 1;
                } else
                        server->oplocks = false;

                server->echo_credits = 1;
        }
        server->credits -= server->echo_credits + server->oplock_credits;
        return 0;
}

static void
smb2_add_credits(struct TCP_Server_Info *server, const unsigned int add,
                 const int optype)
{
        int *val, rc = 0;
        spin_lock(&server->req_lock);
        val = server->ops->get_credits_field(server, optype);
        *val += add;
        if (*val > 65000) {
                *val = 65000; /* Don't get near 64K credits, avoid srv bugs */
                printk_once(KERN_WARNING "server overflowed SMB3 credits\n");
        }
        server->in_flight--;
        if (server->in_flight == 0 && (optype & CIFS_OP_MASK) != CIFS_NEG_OP)
                rc = change_conf(server);
        /*
         * Sometimes server returns 0 credits on oplock break ack - we need to
         * rebalance credits in this case.
         */
        else if (server->in_flight > 0 && server->oplock_credits == 0 &&
                 server->oplocks) {
                if (server->credits > 1) {
                        server->credits--;
                        server->oplock_credits++;
                }
        }
        spin_unlock(&server->req_lock);
        wake_up(&server->request_q);
        if (rc)
                cifs_reconnect(server);
}

static void
smb2_set_credits(struct TCP_Server_Info *server, const int val)
{
        spin_lock(&server->req_lock);
        server->credits = val;
        spin_unlock(&server->req_lock);
}

static int *
smb2_get_credits_field(struct TCP_Server_Info *server, const int optype)
{
        switch (optype) {
        case CIFS_ECHO_OP:
                return &server->echo_credits;
        case CIFS_OBREAK_OP:
                return &server->oplock_credits;
        default:
                return &server->credits;
        }
}

static unsigned int
smb2_get_credits(struct mid_q_entry *mid)
{
        struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)mid->resp_buf;

        return le16_to_cpu(shdr->CreditRequest);
}

static int
smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
                      unsigned int *num, unsigned int *credits)
{
        int rc = 0;
        unsigned int scredits;

        spin_lock(&server->req_lock);
        while (1) {
                if (server->credits <= 0) {
                        spin_unlock(&server->req_lock);
                        cifs_num_waiters_inc(server);
                        rc = wait_event_killable(server->request_q,
                                        has_credits(server, &server->credits));
                        cifs_num_waiters_dec(server);
                        if (rc)
                                return rc;
                        spin_lock(&server->req_lock);
                } else {
                        if (server->tcpStatus == CifsExiting) {
                                spin_unlock(&server->req_lock);
                                return -ENOENT;
                        }

                        scredits = server->credits;
                        /* can deadlock with reopen */
                        if (scredits == 1) {
                                *num = SMB2_MAX_BUFFER_SIZE;
                                *credits = 0;
                                break;
                        }

                        /* leave one credit for a possible reopen */
                        scredits--;
                        *num = min_t(unsigned int, size,
                                     scredits * SMB2_MAX_BUFFER_SIZE);

                        *credits = DIV_ROUND_UP(*num, SMB2_MAX_BUFFER_SIZE);
                        server->credits -= *credits;
                        server->in_flight++;
                        break;
                }
        }
        spin_unlock(&server->req_lock);
        return rc;
}

static __u64
smb2_get_next_mid(struct TCP_Server_Info *server)
{
        __u64 mid;
        /* for SMB2 we need the current value */
        spin_lock(&GlobalMid_Lock);
        mid = server->CurrentMid++;
        spin_unlock(&GlobalMid_Lock);
        return mid;
}

static struct mid_q_entry *
smb2_find_mid(struct TCP_Server_Info *server, char *buf)
{
        struct mid_q_entry *mid;
        struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buf;
        __u64 wire_mid = le64_to_cpu(shdr->MessageId);

        if (shdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM) {
                cifs_dbg(VFS, "encrypted frame parsing not supported yet");
                return NULL;
        }

        spin_lock(&GlobalMid_Lock);
        list_for_each_entry(mid, &server->pending_mid_q, qhead) {
                if ((mid->mid == wire_mid) &&
                    (mid->mid_state == MID_REQUEST_SUBMITTED) &&
                    (mid->command == shdr->Command)) {
                        kref_get(&mid->refcount);
                        spin_unlock(&GlobalMid_Lock);
                        return mid;
                }
        }
        spin_unlock(&GlobalMid_Lock);
        return NULL;
}

static void
smb2_dump_detail(void *buf, struct TCP_Server_Info *server)
{
#ifdef CONFIG_CIFS_DEBUG2
        struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buf;

        cifs_dbg(VFS, "Cmd: %d Err: 0x%x Flags: 0x%x Mid: %llu Pid: %d\n",
                 shdr->Command, shdr->Status, shdr->Flags, shdr->MessageId,
                 shdr->ProcessId);
        cifs_dbg(VFS, "smb buf %p len %u\n", buf,
                 server->ops->calc_smb_size(buf, server));
#endif
}

static bool
smb2_need_neg(struct TCP_Server_Info *server)
{
        return server->max_read == 0;
}

static int
smb2_negotiate(const unsigned int xid, struct cifs_ses *ses)
{
        int rc;
        ses->server->CurrentMid = 0;
        rc = SMB2_negotiate(xid, ses);
        /* BB we probably don't need to retry with modern servers */
        if (rc == -EAGAIN)
                rc = -EHOSTDOWN;
        return rc;
}

static unsigned int
smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
{
        struct TCP_Server_Info *server = tcon->ses->server;
        unsigned int wsize;

        /* start with specified wsize, or default */
        wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE;
        wsize = min_t(unsigned int, wsize, server->max_write);
#ifdef CONFIG_CIFS_SMB_DIRECT
        if (server->rdma) {
                if (server->sign)
                        wsize = min_t(unsigned int,
                                wsize, server->smbd_conn->max_fragmented_send_size);
                else
                        wsize = min_t(unsigned int,
                                wsize, server->smbd_conn->max_readwrite_size);
        }
#endif
        if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
                wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE);

        return wsize;
}

static unsigned int
smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
{
        struct TCP_Server_Info *server = tcon->ses->server;
        unsigned int rsize;

        /* start with specified rsize, or default */
        rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE;
        rsize = min_t(unsigned int, rsize, server->max_read);
#ifdef CONFIG_CIFS_SMB_DIRECT
        if (server->rdma) {
                if (server->sign)
                        rsize = min_t(unsigned int,
                                rsize, server->smbd_conn->max_fragmented_recv_size);
                else
                        rsize = min_t(unsigned int,
                                rsize, server->smbd_conn->max_readwrite_size);
        }
#endif

        if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
                rsize = min_t(unsigned int, rsize, SMB2_MAX_BUFFER_SIZE);

        return rsize;
}


static int
parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
                        size_t buf_len,
                        struct cifs_server_iface **iface_list,
                        size_t *iface_count)
{
        struct network_interface_info_ioctl_rsp *p;
        struct sockaddr_in *addr4;
        struct sockaddr_in6 *addr6;
        struct iface_info_ipv4 *p4;
        struct iface_info_ipv6 *p6;
        struct cifs_server_iface *info;
        ssize_t bytes_left;
        size_t next = 0;
        int nb_iface = 0;
        int rc = 0;

        *iface_list = NULL;
        *iface_count = 0;

        /*
         * Fist pass: count and sanity check
         */

        bytes_left = buf_len;
        p = buf;
        while (bytes_left >= sizeof(*p)) {
                nb_iface++;
                next = le32_to_cpu(p->Next);
                if (!next) {
                        bytes_left -= sizeof(*p);
                        break;
                }
                p = (struct network_interface_info_ioctl_rsp *)((u8 *)p+next);
                bytes_left -= next;
        }

        if (!nb_iface) {
                cifs_dbg(VFS, "%s: malformed interface info\n", __func__);
                rc = -EINVAL;
                goto out;
        }

        if (bytes_left || p->Next)
                cifs_dbg(VFS, "%s: incomplete interface info\n", __func__);


        /*
         * Second pass: extract info to internal structure
         */

        *iface_list = kcalloc(nb_iface, sizeof(**iface_list), GFP_KERNEL);
        if (!*iface_list) {
                rc = -ENOMEM;
                goto out;
        }

        info = *iface_list;
        bytes_left = buf_len;
        p = buf;
        while (bytes_left >= sizeof(*p)) {
                info->speed = le64_to_cpu(p->LinkSpeed);
                info->rdma_capable = le32_to_cpu(p->Capability & RDMA_CAPABLE);
                info->rss_capable = le32_to_cpu(p->Capability & RSS_CAPABLE);

                cifs_dbg(FYI, "%s: adding iface %zu\n", __func__, *iface_count);
                cifs_dbg(FYI, "%s: speed %zu bps\n", __func__, info->speed);
                cifs_dbg(FYI, "%s: capabilities 0x%08x\n", __func__,
                         le32_to_cpu(p->Capability));

                switch (p->Family) {
                /*
                 * The kernel and wire socket structures have the same
                 * layout and use network byte order but make the
                 * conversion explicit in case either one changes.
                 */
                case INTERNETWORK:
                        addr4 = (struct sockaddr_in *)&info->sockaddr;
                        p4 = (struct iface_info_ipv4 *)p->Buffer;
                        addr4->sin_family = AF_INET;
                        memcpy(&addr4->sin_addr, &p4->IPv4Address, 4);

                        /* [MS-SMB2] 2.2.32.5.1.1 Clients MUST ignore these */
                        addr4->sin_port = cpu_to_be16(CIFS_PORT);

                        cifs_dbg(FYI, "%s: ipv4 %pI4\n", __func__,
                                 &addr4->sin_addr);
                        break;
                case INTERNETWORKV6:
                        addr6 = (struct sockaddr_in6 *)&info->sockaddr;
                        p6 = (struct iface_info_ipv6 *)p->Buffer;
                        addr6->sin6_family = AF_INET6;
                        memcpy(&addr6->sin6_addr, &p6->IPv6Address, 16);

                        /* [MS-SMB2] 2.2.32.5.1.2 Clients MUST ignore these */
                        addr6->sin6_flowinfo = 0;
                        addr6->sin6_scope_id = 0;
                        addr6->sin6_port = cpu_to_be16(CIFS_PORT);

                        cifs_dbg(FYI, "%s: ipv6 %pI6\n", __func__,
                                 &addr6->sin6_addr);
                        break;
                default:
                        cifs_dbg(VFS,
                                 "%s: skipping unsupported socket family\n",
                                 __func__);
                        goto next_iface;
                }

                (*iface_count)++;
                info++;
next_iface:
                next = le32_to_cpu(p->Next);
                if (!next)
                        break;
                p = (struct network_interface_info_ioctl_rsp *)((u8 *)p+next);
                bytes_left -= next;
        }

        if (!*iface_count) {
                rc = -EINVAL;
                goto out;
        }

out:
        if (rc) {
                kfree(*iface_list);
                *iface_count = 0;
                *iface_list = NULL;
        }
        return rc;
}


static int
SMB3_request_interfaces(const unsigned int xid, struct cifs_tcon *tcon)
{
        int rc;
        unsigned int ret_data_len = 0;
        struct network_interface_info_ioctl_rsp *out_buf = NULL;
        struct cifs_server_iface *iface_list;
        size_t iface_count;
        struct cifs_ses *ses = tcon->ses;

        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                        FSCTL_QUERY_NETWORK_INTERFACE_INFO, true /* is_fsctl */,
                        NULL /* no data input */, 0 /* no data input */,
                        (char **)&out_buf, &ret_data_len);
        if (rc != 0) {
                cifs_dbg(VFS, "error %d on ioctl to get interface list\n", rc);
                goto out;
        }

        rc = parse_server_interfaces(out_buf, ret_data_len,
                                     &iface_list, &iface_count);
        if (rc)
                goto out;

        spin_lock(&ses->iface_lock);
        kfree(ses->iface_list);
        ses->iface_list = iface_list;
        ses->iface_count = iface_count;
        ses->iface_last_update = jiffies;
        spin_unlock(&ses->iface_lock);

out:
        kfree(out_buf);
        return rc;
}

void
smb2_cached_lease_break(struct work_struct *work)
{
        struct cached_fid *cfid = container_of(work,
                                struct cached_fid, lease_break);
        mutex_lock(&cfid->fid_mutex);
        if (cfid->is_valid) {
                cifs_dbg(FYI, "clear cached root file handle\n");
                SMB2_close(0, cfid->tcon, cfid->fid->persistent_fid,
                           cfid->fid->volatile_fid);
                cfid->is_valid = false;
        }
        mutex_unlock(&cfid->fid_mutex);
}

/*
 * Open the directory at the root of a share
 */
int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
{
        struct cifs_open_parms oparams;
        int rc;
        __le16 srch_path = 0; /* Null - since an open of top of share */
        u8 oplock = SMB2_OPLOCK_LEVEL_II;

        mutex_lock(&tcon->crfid.fid_mutex);
        if (tcon->crfid.is_valid) {
                cifs_dbg(FYI, "found a cached root file handle\n");
                memcpy(pfid, tcon->crfid.fid, sizeof(struct cifs_fid));
                mutex_unlock(&tcon->crfid.fid_mutex);
                return 0;
        }

        oparams.tcon = tcon;
        oparams.create_options = 0;
        oparams.desired_access = FILE_READ_ATTRIBUTES;
        oparams.disposition = FILE_OPEN;
        oparams.fid = pfid;
        oparams.reconnect = false;

        rc = SMB2_open(xid, &oparams, &srch_path, &oplock, NULL, NULL, NULL);
        if (rc == 0) {
                memcpy(tcon->crfid.fid, pfid, sizeof(struct cifs_fid));
                tcon->crfid.tcon = tcon;
                tcon->crfid.is_valid = true;
        }
        mutex_unlock(&tcon->crfid.fid_mutex);
        return rc;
}

static void
smb3_qfs_tcon(const unsigned int xid, struct cifs_tcon *tcon)
{
        int rc;
        __le16 srch_path = 0; /* Null - open root of share */
        u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;
        bool no_cached_open = tcon->nohandlecache;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_ATTRIBUTES;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        if (no_cached_open)
                rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL,
                               NULL);
        else
                rc = open_shroot(xid, tcon, &fid);

        if (rc)
                return;

        SMB3_request_interfaces(xid, tcon);

        SMB2_QFS_attr(xid, tcon, fid.persistent_fid, fid.volatile_fid,
                        FS_ATTRIBUTE_INFORMATION);
        SMB2_QFS_attr(xid, tcon, fid.persistent_fid, fid.volatile_fid,
                        FS_DEVICE_INFORMATION);
        SMB2_QFS_attr(xid, tcon, fid.persistent_fid, fid.volatile_fid,
                        FS_SECTOR_SIZE_INFORMATION); /* SMB3 specific */
        if (no_cached_open)
                SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
        return;
}

static void
smb2_qfs_tcon(const unsigned int xid, struct cifs_tcon *tcon)
{
        int rc;
        __le16 srch_path = 0; /* Null - open root of share */
        u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_ATTRIBUTES;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL, NULL);
        if (rc)
                return;

        SMB2_QFS_attr(xid, tcon, fid.persistent_fid, fid.volatile_fid,
                        FS_ATTRIBUTE_INFORMATION);
        SMB2_QFS_attr(xid, tcon, fid.persistent_fid, fid.volatile_fid,
                        FS_DEVICE_INFORMATION);
        SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
        return;
}

static int
smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
                        struct cifs_sb_info *cifs_sb, const char *full_path)
{
        int rc;
        __le16 *utf16_path;
        __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;

        if ((*full_path == 0) && tcon->crfid.is_valid)
                return 0;

        utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
        if (!utf16_path)
                return -ENOMEM;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_ATTRIBUTES;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
        if (rc) {
                kfree(utf16_path);
                return rc;
        }

        rc = SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
        kfree(utf16_path);
        return rc;
}

static int
smb2_get_srv_inum(const unsigned int xid, struct cifs_tcon *tcon,
                  struct cifs_sb_info *cifs_sb, const char *full_path,
                  u64 *uniqueid, FILE_ALL_INFO *data)
{
        *uniqueid = le64_to_cpu(data->IndexNumber);
        return 0;
}

static int
smb2_query_file_info(const unsigned int xid, struct cifs_tcon *tcon,
                     struct cifs_fid *fid, FILE_ALL_INFO *data)
{
        int rc;
        struct smb2_file_all_info *smb2_data;

        smb2_data = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2,
                            GFP_KERNEL);
        if (smb2_data == NULL)
                return -ENOMEM;

        rc = SMB2_query_info(xid, tcon, fid->persistent_fid, fid->volatile_fid,
                             smb2_data);
        if (!rc)
                move_smb2_info_to_cifs(data, smb2_data);
        kfree(smb2_data);
        return rc;
}

#ifdef CONFIG_CIFS_XATTR
static ssize_t
move_smb2_ea_to_cifs(char *dst, size_t dst_size,
                     struct smb2_file_full_ea_info *src, size_t src_size,
                     const unsigned char *ea_name)
{
        int rc = 0;
        unsigned int ea_name_len = ea_name ? strlen(ea_name) : 0;
        char *name, *value;
        size_t name_len, value_len, user_name_len;

        while (src_size > 0) {
                name = &src->ea_data[0];
                name_len = (size_t)src->ea_name_length;
                value = &src->ea_data[src->ea_name_length + 1];
                value_len = (size_t)le16_to_cpu(src->ea_value_length);

                if (name_len == 0) {
                        break;
                }

                if (src_size < 8 + name_len + 1 + value_len) {
                        cifs_dbg(FYI, "EA entry goes beyond length of list\n");
                        rc = -EIO;
                        goto out;
                }

                if (ea_name) {
                        if (ea_name_len == name_len &&
                            memcmp(ea_name, name, name_len) == 0) {
                                rc = value_len;
                                if (dst_size == 0)
                                        goto out;
                                if (dst_size < value_len) {
                                        rc = -ERANGE;
                                        goto out;
                                }
                                memcpy(dst, value, value_len);
                                goto out;
                        }
                } else {
                        /* 'user.' plus a terminating null */
                        user_name_len = 5 + 1 + name_len;

                        rc += user_name_len;

                        if (dst_size >= user_name_len) {
                                dst_size -= user_name_len;
                                memcpy(dst, "user.", 5);
                                dst += 5;
                                memcpy(dst, src->ea_data, name_len);
                                dst += name_len;
                                *dst = 0;
                                ++dst;
                        } else if (dst_size == 0) {
                                /* skip copy - calc size only */
                        } else {
                                /* stop before overrun buffer */
                                rc = -ERANGE;
                                break;
                        }
                }

                if (!src->next_entry_offset)
                        break;

                if (src_size < le32_to_cpu(src->next_entry_offset)) {
                        /* stop before overrun buffer */
                        rc = -ERANGE;
                        break;
                }
                src_size -= le32_to_cpu(src->next_entry_offset);
                src = (void *)((char *)src +
                               le32_to_cpu(src->next_entry_offset));
        }

        /* didn't find the named attribute */
        if (ea_name)
                rc = -ENODATA;

out:
        return (ssize_t)rc;
}

static ssize_t
smb2_query_eas(const unsigned int xid, struct cifs_tcon *tcon,
               const unsigned char *path, const unsigned char *ea_name,
               char *ea_data, size_t buf_size,
               struct cifs_sb_info *cifs_sb)
{
        int rc;
        __le16 *utf16_path;
        __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;
        struct smb2_file_full_ea_info *smb2_data;
        int ea_buf_size = SMB2_MIN_EA_BUF;

        utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
        if (!utf16_path)
                return -ENOMEM;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_EA;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
        kfree(utf16_path);
        if (rc) {
                cifs_dbg(FYI, "open failed rc=%d\n", rc);
                return rc;
        }

        while (1) {
                smb2_data = kzalloc(ea_buf_size, GFP_KERNEL);
                if (smb2_data == NULL) {
                        SMB2_close(xid, tcon, fid.persistent_fid,
                                   fid.volatile_fid);
                        return -ENOMEM;
                }

                rc = SMB2_query_eas(xid, tcon, fid.persistent_fid,
                                    fid.volatile_fid,
                                    ea_buf_size, smb2_data);

                if (rc != -E2BIG)
                        break;

                kfree(smb2_data);
                ea_buf_size <<= 1;

                if (ea_buf_size > SMB2_MAX_EA_BUF) {
                        cifs_dbg(VFS, "EA size is too large\n");
                        SMB2_close(xid, tcon, fid.persistent_fid,
                                   fid.volatile_fid);
                        return -ENOMEM;
                }
        }

        SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);

        /*
         * If ea_name is NULL (listxattr) and there are no EAs, return 0 as it's
         * not an error. Otherwise, the specified ea_name was not found.
         */
        if (!rc)
                rc = move_smb2_ea_to_cifs(ea_data, buf_size, smb2_data,
                                          SMB2_MAX_EA_BUF, ea_name);
        else if (!ea_name && rc == -ENODATA)
                rc = 0;

        kfree(smb2_data);
        return rc;
}


static int
smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
            const char *path, const char *ea_name, const void *ea_value,
            const __u16 ea_value_len, const struct nls_table *nls_codepage,
            struct cifs_sb_info *cifs_sb)
{
        int rc;
        __le16 *utf16_path;
        __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;
        struct smb2_file_full_ea_info *ea;
        int ea_name_len = strlen(ea_name);
        int len;

        if (ea_name_len > 255)
                return -EINVAL;

        utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
        if (!utf16_path)
                return -ENOMEM;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_WRITE_EA;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
        kfree(utf16_path);
        if (rc) {
                cifs_dbg(FYI, "open failed rc=%d\n", rc);
                return rc;
        }

        len = sizeof(ea) + ea_name_len + ea_value_len + 1;
        ea = kzalloc(len, GFP_KERNEL);
        if (ea == NULL) {
                SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
                return -ENOMEM;
        }

        ea->ea_name_length = ea_name_len;
        ea->ea_value_length = cpu_to_le16(ea_value_len);
        memcpy(ea->ea_data, ea_name, ea_name_len + 1);
        memcpy(ea->ea_data + ea_name_len + 1, ea_value, ea_value_len);

        rc = SMB2_set_ea(xid, tcon, fid.persistent_fid, fid.volatile_fid, ea,
                         len);
        kfree(ea);

        SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);

        return rc;
}
#endif

static bool
smb2_can_echo(struct TCP_Server_Info *server)
{
        return server->echoes;
}

static void
smb2_clear_stats(struct cifs_tcon *tcon)
{
#ifdef CONFIG_CIFS_STATS
        int i;
        for (i = 0; i < NUMBER_OF_SMB2_COMMANDS; i++) {
                atomic_set(&tcon->stats.smb2_stats.smb2_com_sent[i], 0);
                atomic_set(&tcon->stats.smb2_stats.smb2_com_failed[i], 0);
        }
#endif
}

static void
smb2_dump_share_caps(struct seq_file *m, struct cifs_tcon *tcon)
{
        seq_puts(m, "\n\tShare Capabilities:");
        if (tcon->capabilities & SMB2_SHARE_CAP_DFS)
                seq_puts(m, " DFS,");
        if (tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
                seq_puts(m, " CONTINUOUS AVAILABILITY,");
        if (tcon->capabilities & SMB2_SHARE_CAP_SCALEOUT)
                seq_puts(m, " SCALEOUT,");
        if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER)
                seq_puts(m, " CLUSTER,");
        if (tcon->capabilities & SMB2_SHARE_CAP_ASYMMETRIC)
                seq_puts(m, " ASYMMETRIC,");
        if (tcon->capabilities == 0)
                seq_puts(m, " None");
        if (tcon->ss_flags & SSINFO_FLAGS_ALIGNED_DEVICE)
                seq_puts(m, " Aligned,");
        if (tcon->ss_flags & SSINFO_FLAGS_PARTITION_ALIGNED_ON_DEVICE)
                seq_puts(m, " Partition Aligned,");
        if (tcon->ss_flags & SSINFO_FLAGS_NO_SEEK_PENALTY)
                seq_puts(m, " SSD,");
        if (tcon->ss_flags & SSINFO_FLAGS_TRIM_ENABLED)
                seq_puts(m, " TRIM-support,");

        seq_printf(m, "\tShare Flags: 0x%x", tcon->share_flags);
        seq_printf(m, "\n\ttid: 0x%x", tcon->tid);
        if (tcon->perf_sector_size)
                seq_printf(m, "\tOptimal sector size: 0x%x",
                           tcon->perf_sector_size);
        seq_printf(m, "\tMaximal Access: 0x%x", tcon->maximal_access);
}

static void
smb2_print_stats(struct seq_file *m, struct cifs_tcon *tcon)
{
#ifdef CONFIG_CIFS_STATS
        atomic_t *sent = tcon->stats.smb2_stats.smb2_com_sent;
        atomic_t *failed = tcon->stats.smb2_stats.smb2_com_failed;
        seq_printf(m, "\nNegotiates: %d sent %d failed",
                   atomic_read(&sent[SMB2_NEGOTIATE_HE]),
                   atomic_read(&failed[SMB2_NEGOTIATE_HE]));
        seq_printf(m, "\nSessionSetups: %d sent %d failed",
                   atomic_read(&sent[SMB2_SESSION_SETUP_HE]),
                   atomic_read(&failed[SMB2_SESSION_SETUP_HE]));
        seq_printf(m, "\nLogoffs: %d sent %d failed",
                   atomic_read(&sent[SMB2_LOGOFF_HE]),
                   atomic_read(&failed[SMB2_LOGOFF_HE]));
        seq_printf(m, "\nTreeConnects: %d sent %d failed",
                   atomic_read(&sent[SMB2_TREE_CONNECT_HE]),
                   atomic_read(&failed[SMB2_TREE_CONNECT_HE]));
        seq_printf(m, "\nTreeDisconnects: %d sent %d failed",
                   atomic_read(&sent[SMB2_TREE_DISCONNECT_HE]),
                   atomic_read(&failed[SMB2_TREE_DISCONNECT_HE]));
        seq_printf(m, "\nCreates: %d sent %d failed",
                   atomic_read(&sent[SMB2_CREATE_HE]),
                   atomic_read(&failed[SMB2_CREATE_HE]));
        seq_printf(m, "\nCloses: %d sent %d failed",
                   atomic_read(&sent[SMB2_CLOSE_HE]),
                   atomic_read(&failed[SMB2_CLOSE_HE]));
        seq_printf(m, "\nFlushes: %d sent %d failed",
                   atomic_read(&sent[SMB2_FLUSH_HE]),
                   atomic_read(&failed[SMB2_FLUSH_HE]));
        seq_printf(m, "\nReads: %d sent %d failed",
                   atomic_read(&sent[SMB2_READ_HE]),
                   atomic_read(&failed[SMB2_READ_HE]));
        seq_printf(m, "\nWrites: %d sent %d failed",
                   atomic_read(&sent[SMB2_WRITE_HE]),
                   atomic_read(&failed[SMB2_WRITE_HE]));
        seq_printf(m, "\nLocks: %d sent %d failed",
                   atomic_read(&sent[SMB2_LOCK_HE]),
                   atomic_read(&failed[SMB2_LOCK_HE]));
        seq_printf(m, "\nIOCTLs: %d sent %d failed",
                   atomic_read(&sent[SMB2_IOCTL_HE]),
                   atomic_read(&failed[SMB2_IOCTL_HE]));
        seq_printf(m, "\nCancels: %d sent %d failed",
                   atomic_read(&sent[SMB2_CANCEL_HE]),
                   atomic_read(&failed[SMB2_CANCEL_HE]));
        seq_printf(m, "\nEchos: %d sent %d failed",
                   atomic_read(&sent[SMB2_ECHO_HE]),
                   atomic_read(&failed[SMB2_ECHO_HE]));
        seq_printf(m, "\nQueryDirectories: %d sent %d failed",
                   atomic_read(&sent[SMB2_QUERY_DIRECTORY_HE]),
                   atomic_read(&failed[SMB2_QUERY_DIRECTORY_HE]));
        seq_printf(m, "\nChangeNotifies: %d sent %d failed",
                   atomic_read(&sent[SMB2_CHANGE_NOTIFY_HE]),
                   atomic_read(&failed[SMB2_CHANGE_NOTIFY_HE]));
        seq_printf(m, "\nQueryInfos: %d sent %d failed",
                   atomic_read(&sent[SMB2_QUERY_INFO_HE]),
                   atomic_read(&failed[SMB2_QUERY_INFO_HE]));
        seq_printf(m, "\nSetInfos: %d sent %d failed",
                   atomic_read(&sent[SMB2_SET_INFO_HE]),
                   atomic_read(&failed[SMB2_SET_INFO_HE]));
        seq_printf(m, "\nOplockBreaks: %d sent %d failed",
                   atomic_read(&sent[SMB2_OPLOCK_BREAK_HE]),
                   atomic_read(&failed[SMB2_OPLOCK_BREAK_HE]));
#endif
}

static void
smb2_set_fid(struct cifsFileInfo *cfile, struct cifs_fid *fid, __u32 oplock)
{
        struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
        struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;

        cfile->fid.persistent_fid = fid->persistent_fid;
        cfile->fid.volatile_fid = fid->volatile_fid;
        server->ops->set_oplock_level(cinode, oplock, fid->epoch,
                                      &fid->purge_cache);
        cinode->can_cache_brlcks = CIFS_CACHE_WRITE(cinode);
        memcpy(cfile->fid.create_guid, fid->create_guid, 16);
}

static void
smb2_close_file(const unsigned int xid, struct cifs_tcon *tcon,
                struct cifs_fid *fid)

{
        SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

static int
SMB2_request_res_key(const unsigned int xid, struct cifs_tcon *tcon,
                     u64 persistent_fid, u64 volatile_fid,
                     struct copychunk_ioctl *pcchunk)
{
        int rc;
        unsigned int ret_data_len;
        struct resume_key_req *res_key;

        rc = SMB2_ioctl(xid, tcon, persistent_fid, volatile_fid,
                        FSCTL_SRV_REQUEST_RESUME_KEY, true /* is_fsctl */,
                        NULL, 0 /* no input */,
                        (char **)&res_key, &ret_data_len);

        if (rc) {
                cifs_dbg(VFS, "refcpy ioctl error %d getting resume key\n", rc);
                goto req_res_key_exit;
        }
        if (ret_data_len < sizeof(struct resume_key_req)) {
                cifs_dbg(VFS, "Invalid refcopy resume key length\n");
                rc = -EINVAL;
                goto req_res_key_exit;
        }
        memcpy(pcchunk->SourceKey, res_key->ResumeKey, COPY_CHUNK_RES_KEY_SIZE);

req_res_key_exit:
        kfree(res_key);
        return rc;
}

static ssize_t
smb2_copychunk_range(const unsigned int xid,
                        struct cifsFileInfo *srcfile,
                        struct cifsFileInfo *trgtfile, u64 src_off,
                        u64 len, u64 dest_off)
{
        int rc;
        unsigned int ret_data_len;
        struct copychunk_ioctl *pcchunk;
        struct copychunk_ioctl_rsp *retbuf = NULL;
        struct cifs_tcon *tcon;
        int chunks_copied = 0;
        bool chunk_sizes_updated = false;
        ssize_t bytes_written, total_bytes_written = 0;

        pcchunk = kmalloc(sizeof(struct copychunk_ioctl), GFP_KERNEL);

        if (pcchunk == NULL)
                return -ENOMEM;

        cifs_dbg(FYI, "in smb2_copychunk_range - about to call request res key\n");
        /* Request a key from the server to identify the source of the copy */
        rc = SMB2_request_res_key(xid, tlink_tcon(srcfile->tlink),
                                srcfile->fid.persistent_fid,
                                srcfile->fid.volatile_fid, pcchunk);

        /* Note: request_res_key sets res_key null only if rc !=0 */
        if (rc)
                goto cchunk_out;

        /* For now array only one chunk long, will make more flexible later */
        pcchunk->ChunkCount = cpu_to_le32(1);
        pcchunk->Reserved = 0;
        pcchunk->Reserved2 = 0;

        tcon = tlink_tcon(trgtfile->tlink);

        while (len > 0) {
                pcchunk->SourceOffset = cpu_to_le64(src_off);
                pcchunk->TargetOffset = cpu_to_le64(dest_off);
                pcchunk->Length =
                        cpu_to_le32(min_t(u32, len, tcon->max_bytes_chunk));

                /* Request server copy to target from src identified by key */
                rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
                        trgtfile->fid.volatile_fid, FSCTL_SRV_COPYCHUNK_WRITE,
                        true /* is_fsctl */, (char *)pcchunk,
                        sizeof(struct copychunk_ioctl), (char **)&retbuf,
                        &ret_data_len);
                if (rc == 0) {
                        if (ret_data_len !=
                                        sizeof(struct copychunk_ioctl_rsp)) {
                                cifs_dbg(VFS, "invalid cchunk response size\n");
                                rc = -EIO;
                                goto cchunk_out;
                        }
                        if (retbuf->TotalBytesWritten == 0) {
                                cifs_dbg(FYI, "no bytes copied\n");
                                rc = -EIO;
                                goto cchunk_out;
                        }
                        /*
                         * Check if server claimed to write more than we asked
                         */
                        if (le32_to_cpu(retbuf->TotalBytesWritten) >
                            le32_to_cpu(pcchunk->Length)) {
                                cifs_dbg(VFS, "invalid copy chunk response\n");
                                rc = -EIO;
                                goto cchunk_out;
                        }
                        if (le32_to_cpu(retbuf->ChunksWritten) != 1) {
                                cifs_dbg(VFS, "invalid num chunks written\n");
                                rc = -EIO;
                                goto cchunk_out;
                        }
                        chunks_copied++;

                        bytes_written = le32_to_cpu(retbuf->TotalBytesWritten);
                        src_off += bytes_written;
                        dest_off += bytes_written;
                        len -= bytes_written;
                        total_bytes_written += bytes_written;

                        cifs_dbg(FYI, "Chunks %d PartialChunk %d Total %zu\n",
                                le32_to_cpu(retbuf->ChunksWritten),
                                le32_to_cpu(retbuf->ChunkBytesWritten),
                                bytes_written);
                } else if (rc == -EINVAL) {
                        if (ret_data_len != sizeof(struct copychunk_ioctl_rsp))
                                goto cchunk_out;

                        cifs_dbg(FYI, "MaxChunks %d BytesChunk %d MaxCopy %d\n",
                                le32_to_cpu(retbuf->ChunksWritten),
                                le32_to_cpu(retbuf->ChunkBytesWritten),
                                le32_to_cpu(retbuf->TotalBytesWritten));

                        /*
                         * Check if this is the first request using these sizes,
                         * (ie check if copy succeed once with original sizes
                         * and check if the server gave us different sizes after
                         * we already updated max sizes on previous request).
                         * if not then why is the server returning an error now
                         */
                        if ((chunks_copied != 0) || chunk_sizes_updated)
                                goto cchunk_out;

                        /* Check that server is not asking us to grow size */
                        if (le32_to_cpu(retbuf->ChunkBytesWritten) <
                                        tcon->max_bytes_chunk)
                                tcon->max_bytes_chunk =
                                        le32_to_cpu(retbuf->ChunkBytesWritten);
                        else
                                goto cchunk_out; /* server gave us bogus size */

                        /* No need to change MaxChunks since already set to 1 */
                        chunk_sizes_updated = true;
                } else
                        goto cchunk_out;
        }

cchunk_out:
        kfree(pcchunk);
        kfree(retbuf);
        if (rc)
                return rc;
        else
                return total_bytes_written;
}

static int
smb2_flush_file(const unsigned int xid, struct cifs_tcon *tcon,
                struct cifs_fid *fid)
{
        return SMB2_flush(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

static unsigned int
smb2_read_data_offset(char *buf)
{
        struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;
        return rsp->DataOffset;
}

static unsigned int
smb2_read_data_length(char *buf, bool in_remaining)
{
        struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;

        if (in_remaining)
                return le32_to_cpu(rsp->DataRemaining);

        return le32_to_cpu(rsp->DataLength);
}


static int
smb2_sync_read(const unsigned int xid, struct cifs_fid *pfid,
               struct cifs_io_parms *parms, unsigned int *bytes_read,
               char **buf, int *buf_type)
{
        parms->persistent_fid = pfid->persistent_fid;
        parms->volatile_fid = pfid->volatile_fid;
        return SMB2_read(xid, parms, bytes_read, buf, buf_type);
}

static int
smb2_sync_write(const unsigned int xid, struct cifs_fid *pfid,
                struct cifs_io_parms *parms, unsigned int *written,
                struct kvec *iov, unsigned long nr_segs)
{

        parms->persistent_fid = pfid->persistent_fid;
        parms->volatile_fid = pfid->volatile_fid;
        return SMB2_write(xid, parms, written, iov, nr_segs);
}

/* Set or clear the SPARSE_FILE attribute based on value passed in setsparse */
static bool smb2_set_sparse(const unsigned int xid, struct cifs_tcon *tcon,
                struct cifsFileInfo *cfile, struct inode *inode, __u8 setsparse)
{
        struct cifsInodeInfo *cifsi;
        int rc;

        cifsi = CIFS_I(inode);

        /* if file already sparse don't bother setting sparse again */
        if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) && setsparse)
                return true; /* already sparse */

        if (!(cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) && !setsparse)
                return true; /* already not sparse */

        /*
         * Can't check for sparse support on share the usual way via the
         * FS attribute info (FILE_SUPPORTS_SPARSE_FILES) on the share
         * since Samba server doesn't set the flag on the share, yet
         * supports the set sparse FSCTL and returns sparse correctly
         * in the file attributes. If we fail setting sparse though we
         * mark that server does not support sparse files for this share
         * to avoid repeatedly sending the unsupported fsctl to server
         * if the file is repeatedly extended.
         */
        if (tcon->broken_sparse_sup)
                return false;

        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid, FSCTL_SET_SPARSE,
                        true /* is_fctl */,
                        &setsparse, 1, NULL, NULL);
        if (rc) {
                tcon->broken_sparse_sup = true;
                cifs_dbg(FYI, "set sparse rc = %d\n", rc);
                return false;
        }

        if (setsparse)
                cifsi->cifsAttrs |= FILE_ATTRIBUTE_SPARSE_FILE;
        else
                cifsi->cifsAttrs &= (~FILE_ATTRIBUTE_SPARSE_FILE);

        return true;
}

static int
smb2_set_file_size(const unsigned int xid, struct cifs_tcon *tcon,
                   struct cifsFileInfo *cfile, __u64 size, bool set_alloc)
{
        __le64 eof = cpu_to_le64(size);
        struct inode *inode;

        /*
         * If extending file more than one page make sparse. Many Linux fs
         * make files sparse by default when extending via ftruncate
         */
        inode = d_inode(cfile->dentry);

        if (!set_alloc && (size > inode->i_size + 8192)) {
                __u8 set_sparse = 1;

                /* whether set sparse succeeds or not, extend the file */
                smb2_set_sparse(xid, tcon, cfile, inode, set_sparse);
        }

        return SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
                            cfile->fid.volatile_fid, cfile->pid, &eof, false);
}

static int
smb2_duplicate_extents(const unsigned int xid,
                        struct cifsFileInfo *srcfile,
                        struct cifsFileInfo *trgtfile, u64 src_off,
                        u64 len, u64 dest_off)
{
        int rc;
        unsigned int ret_data_len;
        struct duplicate_extents_to_file dup_ext_buf;
        struct cifs_tcon *tcon = tlink_tcon(trgtfile->tlink);

        /* server fileays advertise duplicate extent support with this flag */
        if ((le32_to_cpu(tcon->fsAttrInfo.Attributes) &
             FILE_SUPPORTS_BLOCK_REFCOUNTING) == 0)
                return -EOPNOTSUPP;

        dup_ext_buf.VolatileFileHandle = srcfile->fid.volatile_fid;
        dup_ext_buf.PersistentFileHandle = srcfile->fid.persistent_fid;
        dup_ext_buf.SourceFileOffset = cpu_to_le64(src_off);
        dup_ext_buf.TargetFileOffset = cpu_to_le64(dest_off);
        dup_ext_buf.ByteCount = cpu_to_le64(len);
        cifs_dbg(FYI, "duplicate extents: src off %lld dst off %lld len %lld",
                src_off, dest_off, len);

        rc = smb2_set_file_size(xid, tcon, trgtfile, dest_off + len, false);
        if (rc)
                goto duplicate_extents_out;

        rc = SMB2_ioctl(xid, tcon, trgtfile->fid.persistent_fid,
                        trgtfile->fid.volatile_fid,
                        FSCTL_DUPLICATE_EXTENTS_TO_FILE,
                        true /* is_fsctl */,
                        (char *)&dup_ext_buf,
                        sizeof(struct duplicate_extents_to_file),
                        NULL,
                        &ret_data_len);

        if (ret_data_len > 0)
                cifs_dbg(FYI, "non-zero response length in duplicate extents");

duplicate_extents_out:
        return rc;
}

static int
smb2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
                   struct cifsFileInfo *cfile)
{
        return SMB2_set_compression(xid, tcon, cfile->fid.persistent_fid,
                            cfile->fid.volatile_fid);
}

static int
smb3_set_integrity(const unsigned int xid, struct cifs_tcon *tcon,
                   struct cifsFileInfo *cfile)
{
        struct fsctl_set_integrity_information_req integr_info;
        unsigned int ret_data_len;

        integr_info.ChecksumAlgorithm = cpu_to_le16(CHECKSUM_TYPE_UNCHANGED);
        integr_info.Flags = 0;
        integr_info.Reserved = 0;

        return SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid,
                        FSCTL_SET_INTEGRITY_INFORMATION,
                        true /* is_fsctl */,
                        (char *)&integr_info,
                        sizeof(struct fsctl_set_integrity_information_req),
                        NULL,
                        &ret_data_len);

}

static int
smb3_enum_snapshots(const unsigned int xid, struct cifs_tcon *tcon,
                   struct cifsFileInfo *cfile, void __user *ioc_buf)
{
        char *retbuf = NULL;
        unsigned int ret_data_len = 0;
        int rc;
        struct smb_snapshot_array snapshot_in;

        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid,
                        FSCTL_SRV_ENUMERATE_SNAPSHOTS,
                        true /* is_fsctl */,
                        NULL, 0 /* no input data */,
                        (char **)&retbuf,
                        &ret_data_len);
        cifs_dbg(FYI, "enum snaphots ioctl returned %d and ret buflen is %d\n",
                        rc, ret_data_len);
        if (rc)
                return rc;

        if (ret_data_len && (ioc_buf != NULL) && (retbuf != NULL)) {
                /* Fixup buffer */
                if (copy_from_user(&snapshot_in, ioc_buf,
                    sizeof(struct smb_snapshot_array))) {
                        rc = -EFAULT;
                        kfree(retbuf);
                        return rc;
                }
                if (snapshot_in.snapshot_array_size < sizeof(struct smb_snapshot_array)) {
                        rc = -ERANGE;
                        kfree(retbuf);
                        return rc;
                }

                if (ret_data_len > snapshot_in.snapshot_array_size)
                        ret_data_len = snapshot_in.snapshot_array_size;

                if (copy_to_user(ioc_buf, retbuf, ret_data_len))
                        rc = -EFAULT;
        }

        kfree(retbuf);
        return rc;
}

static int
smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
                     const char *path, struct cifs_sb_info *cifs_sb,
                     struct cifs_fid *fid, __u16 search_flags,
                     struct cifs_search_info *srch_inf)
{
        __le16 *utf16_path;
        int rc;
        __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;

        utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
        if (!utf16_path)
                return -ENOMEM;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_ATTRIBUTES | FILE_READ_DATA;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
        kfree(utf16_path);
        if (rc) {
                cifs_dbg(FYI, "open dir failed rc=%d\n", rc);
                return rc;
        }

        srch_inf->entries_in_buffer = 0;
        srch_inf->index_of_last_entry = 0;

        rc = SMB2_query_directory(xid, tcon, fid->persistent_fid,
                                  fid->volatile_fid, 0, srch_inf);
        if (rc) {
                cifs_dbg(FYI, "query directory failed rc=%d\n", rc);
                SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
        }
        return rc;
}

static int
smb2_query_dir_next(const unsigned int xid, struct cifs_tcon *tcon,
                    struct cifs_fid *fid, __u16 search_flags,
                    struct cifs_search_info *srch_inf)
{
        return SMB2_query_directory(xid, tcon, fid->persistent_fid,
                                    fid->volatile_fid, 0, srch_inf);
}

static int
smb2_close_dir(const unsigned int xid, struct cifs_tcon *tcon,
               struct cifs_fid *fid)
{
        return SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

/*
* If we negotiate SMB2 protocol and get STATUS_PENDING - update
* the number of credits and return true. Otherwise - return false.
*/
static bool
smb2_is_status_pending(char *buf, struct TCP_Server_Info *server, int length)
{
        struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buf;

        if (shdr->Status != STATUS_PENDING)
                return false;

        if (!length) {
                spin_lock(&server->req_lock);
                server->credits += le16_to_cpu(shdr->CreditRequest);
                spin_unlock(&server->req_lock);
                wake_up(&server->request_q);
        }

        return true;
}

static bool
smb2_is_session_expired(char *buf)
{
        struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buf;

        if (shdr->Status != STATUS_NETWORK_SESSION_EXPIRED &&
            shdr->Status != STATUS_USER_SESSION_DELETED)
                return false;

        cifs_dbg(FYI, "Session expired or deleted\n");
        return true;
}

static int
smb2_oplock_response(struct cifs_tcon *tcon, struct cifs_fid *fid,
                     struct cifsInodeInfo *cinode)
{
        if (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
                return SMB2_lease_break(0, tcon, cinode->lease_key,
                                        smb2_get_lease_state(cinode));

        return SMB2_oplock_break(0, tcon, fid->persistent_fid,
                                 fid->volatile_fid,
                                 CIFS_CACHE_READ(cinode) ? 1 : 0);
}

static int
smb2_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
             struct kstatfs *buf)
{
        int rc;
        __le16 srch_path = 0; /* Null - open root of share */
        u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_ATTRIBUTES;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL, NULL);
        if (rc)
                return rc;
        buf->f_type = SMB2_MAGIC_NUMBER;
        rc = SMB2_QFS_info(xid, tcon, fid.persistent_fid, fid.volatile_fid,
                           buf);
        SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
        return rc;
}

static int
smb311_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
             struct kstatfs *buf)
{
        int rc;
        __le16 srch_path = 0; /* Null - open root of share */
        u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;

        if (!tcon->posix_extensions)
                return smb2_queryfs(xid, tcon, buf);

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_ATTRIBUTES;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL, NULL);
        if (rc)
                return rc;

        rc = SMB311_posix_qfs_info(xid, tcon, fid.persistent_fid,
                                   fid.volatile_fid, buf);
        buf->f_type = SMB2_MAGIC_NUMBER;
        SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
        return rc;
}

static bool
smb2_compare_fids(struct cifsFileInfo *ob1, struct cifsFileInfo *ob2)
{
        return ob1->fid.persistent_fid == ob2->fid.persistent_fid &&
               ob1->fid.volatile_fid == ob2->fid.volatile_fid;
}

static int
smb2_mand_lock(const unsigned int xid, struct cifsFileInfo *cfile, __u64 offset,
               __u64 length, __u32 type, int lock, int unlock, bool wait)
{
        if (unlock && !lock)
                type = SMB2_LOCKFLAG_UNLOCK;
        return SMB2_lock(xid, tlink_tcon(cfile->tlink),
                         cfile->fid.persistent_fid, cfile->fid.volatile_fid,
                         current->tgid, length, offset, type, wait);
}

static void
smb2_get_lease_key(struct inode *inode, struct cifs_fid *fid)
{
        memcpy(fid->lease_key, CIFS_I(inode)->lease_key, SMB2_LEASE_KEY_SIZE);
}

static void
smb2_set_lease_key(struct inode *inode, struct cifs_fid *fid)
{
        memcpy(CIFS_I(inode)->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
}

static void
smb2_new_lease_key(struct cifs_fid *fid)
{
        generate_random_uuid(fid->lease_key);
}

static int
smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
                   const char *search_name,
                   struct dfs_info3_param **target_nodes,
                   unsigned int *num_of_nodes,
                   const struct nls_table *nls_codepage, int remap)
{
        int rc;
        __le16 *utf16_path = NULL;
        int utf16_path_len = 0;
        struct cifs_tcon *tcon;
        struct fsctl_get_dfs_referral_req *dfs_req = NULL;
        struct get_dfs_referral_rsp *dfs_rsp = NULL;
        u32 dfs_req_size = 0, dfs_rsp_size = 0;

        cifs_dbg(FYI, "smb2_get_dfs_refer path <%s>\n", search_name);

        /*
         * Try to use the IPC tcon, otherwise just use any
         */
        tcon = ses->tcon_ipc;
        if (tcon == NULL) {
                spin_lock(&cifs_tcp_ses_lock);
                tcon = list_first_entry_or_null(&ses->tcon_list,
                                                struct cifs_tcon,
                                                tcon_list);
                if (tcon)
                        tcon->tc_count++;
                spin_unlock(&cifs_tcp_ses_lock);
        }

        if (tcon == NULL) {
                cifs_dbg(VFS, "session %p has no tcon available for a dfs referral request\n",
                         ses);
                rc = -ENOTCONN;
                goto out;
        }

        utf16_path = cifs_strndup_to_utf16(search_name, PATH_MAX,
                                           &utf16_path_len,
                                           nls_codepage, remap);
        if (!utf16_path) {
                rc = -ENOMEM;
                goto out;
        }

        dfs_req_size = sizeof(*dfs_req) + utf16_path_len;
        dfs_req = kzalloc(dfs_req_size, GFP_KERNEL);
        if (!dfs_req) {
                rc = -ENOMEM;
                goto out;
        }

        /* Highest DFS referral version understood */
        dfs_req->MaxReferralLevel = DFS_VERSION;

        /* Path to resolve in an UTF-16 null-terminated string */
        memcpy(dfs_req->RequestFileName, utf16_path, utf16_path_len);

        do {
                rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                                FSCTL_DFS_GET_REFERRALS,
                                true /* is_fsctl */,
                                (char *)dfs_req, dfs_req_size,
                                (char **)&dfs_rsp, &dfs_rsp_size);
        } while (rc == -EAGAIN);

        if (rc) {
                if ((rc != -ENOENT) && (rc != -EOPNOTSUPP))
                        cifs_dbg(VFS, "ioctl error in smb2_get_dfs_refer rc=%d\n", rc);
                goto out;
        }

        rc = parse_dfs_referrals(dfs_rsp, dfs_rsp_size,
                                 num_of_nodes, target_nodes,
                                 nls_codepage, remap, search_name,
                                 true /* is_unicode */);
        if (rc) {
                cifs_dbg(VFS, "parse error in smb2_get_dfs_refer rc=%d\n", rc);
                goto out;
        }

 out:
        if (tcon && !tcon->ipc) {
                /* ipc tcons are not refcounted */
                spin_lock(&cifs_tcp_ses_lock);
                tcon->tc_count--;
                spin_unlock(&cifs_tcp_ses_lock);
        }
        kfree(utf16_path);
        kfree(dfs_req);
        kfree(dfs_rsp);
        return rc;
}
#define SMB2_SYMLINK_STRUCT_SIZE \
        (sizeof(struct smb2_err_rsp) - 1 + sizeof(struct smb2_symlink_err_rsp))

static int
smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
                   const char *full_path, char **target_path,
                   struct cifs_sb_info *cifs_sb)
{
        int rc;
        __le16 *utf16_path;
        __u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        struct cifs_open_parms oparms;
        struct cifs_fid fid;
        struct kvec err_iov = {NULL, 0};
        struct smb2_err_rsp *err_buf = NULL;
        int resp_buftype;
        struct smb2_symlink_err_rsp *symlink;
        unsigned int sub_len;
        unsigned int sub_offset;
        unsigned int print_len;
        unsigned int print_offset;

        cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);

        utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
        if (!utf16_path)
                return -ENOMEM;

        oparms.tcon = tcon;
        oparms.desired_access = FILE_READ_ATTRIBUTES;
        oparms.disposition = FILE_OPEN;
        oparms.create_options = 0;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, &err_iov,
                       &resp_buftype);
        if (!rc || !err_iov.iov_base) {
                rc = -ENOENT;
                goto querty_exit;
        }

        err_buf = err_iov.iov_base;
        if (le32_to_cpu(err_buf->ByteCount) < sizeof(struct smb2_symlink_err_rsp) ||
            err_iov.iov_len < SMB2_SYMLINK_STRUCT_SIZE) {
                rc = -ENOENT;
                goto querty_exit;
        }

        /* open must fail on symlink - reset rc */
        rc = 0;
        symlink = (struct smb2_symlink_err_rsp *)err_buf->ErrorData;
        sub_len = le16_to_cpu(symlink->SubstituteNameLength);
        sub_offset = le16_to_cpu(symlink->SubstituteNameOffset);
        print_len = le16_to_cpu(symlink->PrintNameLength);
        print_offset = le16_to_cpu(symlink->PrintNameOffset);

        if (err_iov.iov_len < SMB2_SYMLINK_STRUCT_SIZE + sub_offset + sub_len) {
                rc = -ENOENT;
                goto querty_exit;
        }

        if (err_iov.iov_len <
            SMB2_SYMLINK_STRUCT_SIZE + print_offset + print_len) {
                rc = -ENOENT;
                goto querty_exit;
        }

        *target_path = cifs_strndup_from_utf16(
                                (char *)symlink->PathBuffer + sub_offset,
                                sub_len, true, cifs_sb->local_nls);
        if (!(*target_path)) {
                rc = -ENOMEM;
                goto querty_exit;
        }
        convert_delimiter(*target_path, '/');
        cifs_dbg(FYI, "%s: target path: %s\n", __func__, *target_path);

 querty_exit:
        free_rsp_buf(resp_buftype, err_buf);
        kfree(utf16_path);
        return rc;
}

#ifdef CONFIG_CIFS_ACL
static struct cifs_ntsd *
get_smb2_acl_by_fid(struct cifs_sb_info *cifs_sb,
                const struct cifs_fid *cifsfid, u32 *pacllen)
{
        struct cifs_ntsd *pntsd = NULL;
        unsigned int xid;
        int rc = -EOPNOTSUPP;
        struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);

        if (IS_ERR(tlink))
                return ERR_CAST(tlink);

        xid = get_xid();
        cifs_dbg(FYI, "trying to get acl\n");

        rc = SMB2_query_acl(xid, tlink_tcon(tlink), cifsfid->persistent_fid,
                            cifsfid->volatile_fid, (void **)&pntsd, pacllen);
        free_xid(xid);

        cifs_put_tlink(tlink);

        cifs_dbg(FYI, "%s: rc = %d ACL len %d\n", __func__, rc, *pacllen);
        if (rc)
                return ERR_PTR(rc);
        return pntsd;

}

static struct cifs_ntsd *
get_smb2_acl_by_path(struct cifs_sb_info *cifs_sb,
                const char *path, u32 *pacllen)
{
        struct cifs_ntsd *pntsd = NULL;
        u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        unsigned int xid;
        int rc;
        struct cifs_tcon *tcon;
        struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
        struct cifs_fid fid;
        struct cifs_open_parms oparms;
        __le16 *utf16_path;

        cifs_dbg(FYI, "get smb3 acl for path %s\n", path);
        if (IS_ERR(tlink))
                return ERR_CAST(tlink);

        tcon = tlink_tcon(tlink);
        xid = get_xid();

        if (backup_cred(cifs_sb))
                oparms.create_options = CREATE_OPEN_BACKUP_INTENT;
        else
                oparms.create_options = 0;

        utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
        if (!utf16_path) {
                rc = -ENOMEM;
                free_xid(xid);
                return ERR_PTR(rc);
        }

        oparms.tcon = tcon;
        oparms.desired_access = READ_CONTROL;
        oparms.disposition = FILE_OPEN;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
        kfree(utf16_path);
        if (!rc) {
                rc = SMB2_query_acl(xid, tlink_tcon(tlink), fid.persistent_fid,
                            fid.volatile_fid, (void **)&pntsd, pacllen);
                SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
        }

        cifs_put_tlink(tlink);
        free_xid(xid);

        cifs_dbg(FYI, "%s: rc = %d ACL len %d\n", __func__, rc, *pacllen);
        if (rc)
                return ERR_PTR(rc);
        return pntsd;
}

#ifdef CONFIG_CIFS_ACL
static int
set_smb2_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
                struct inode *inode, const char *path, int aclflag)
{
        u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
        unsigned int xid;
        int rc, access_flags = 0;
        struct cifs_tcon *tcon;
        struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
        struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
        struct cifs_fid fid;
        struct cifs_open_parms oparms;
        __le16 *utf16_path;

        cifs_dbg(FYI, "set smb3 acl for path %s\n", path);
        if (IS_ERR(tlink))
                return PTR_ERR(tlink);

        tcon = tlink_tcon(tlink);
        xid = get_xid();

        if (backup_cred(cifs_sb))
                oparms.create_options = CREATE_OPEN_BACKUP_INTENT;
        else
                oparms.create_options = 0;

        if (aclflag == CIFS_ACL_OWNER || aclflag == CIFS_ACL_GROUP)
                access_flags = WRITE_OWNER;
        else
                access_flags = WRITE_DAC;

        utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
        if (!utf16_path) {
                rc = -ENOMEM;
                free_xid(xid);
                return rc;
        }

        oparms.tcon = tcon;
        oparms.desired_access = access_flags;
        oparms.disposition = FILE_OPEN;
        oparms.path = path;
        oparms.fid = &fid;
        oparms.reconnect = false;

        rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL);
        kfree(utf16_path);
        if (!rc) {
                rc = SMB2_set_acl(xid, tlink_tcon(tlink), fid.persistent_fid,
                            fid.volatile_fid, pnntsd, acllen, aclflag);
                SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
        }

        cifs_put_tlink(tlink);
        free_xid(xid);
        return rc;
}
#endif /* CIFS_ACL */

/* Retrieve an ACL from the server */
static struct cifs_ntsd *
get_smb2_acl(struct cifs_sb_info *cifs_sb,
                                      struct inode *inode, const char *path,
                                      u32 *pacllen)
{
        struct cifs_ntsd *pntsd = NULL;
        struct cifsFileInfo *open_file = NULL;

        if (inode)
                open_file = find_readable_file(CIFS_I(inode), true);
        if (!open_file)
                return get_smb2_acl_by_path(cifs_sb, path, pacllen);

        pntsd = get_smb2_acl_by_fid(cifs_sb, &open_file->fid, pacllen);
        cifsFileInfo_put(open_file);
        return pntsd;
}
#endif

static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
                            loff_t offset, loff_t len, bool keep_size)
{
        struct inode *inode;
        struct cifsInodeInfo *cifsi;
        struct cifsFileInfo *cfile = file->private_data;
        struct file_zero_data_information fsctl_buf;
        long rc;
        unsigned int xid;

        xid = get_xid();

        inode = d_inode(cfile->dentry);
        cifsi = CIFS_I(inode);

        /* if file not oplocked can't be sure whether asking to extend size */
        if (!CIFS_CACHE_READ(cifsi))
                if (keep_size == false) {
                        rc = -EOPNOTSUPP;
                        free_xid(xid);
                        return rc;
                }

        /*
         * Must check if file sparse since fallocate -z (zero range) assumes
         * non-sparse allocation
         */
        if (!(cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE)) {
                rc = -EOPNOTSUPP;
                free_xid(xid);
                return rc;
        }

        /*
         * need to make sure we are not asked to extend the file since the SMB3
         * fsctl does not change the file size. In the future we could change
         * this to zero the first part of the range then set the file size
         * which for a non sparse file would zero the newly extended range
         */
        if (keep_size == false)
                if (i_size_read(inode) < offset + len) {
                        rc = -EOPNOTSUPP;
                        free_xid(xid);
                        return rc;
                }

        cifs_dbg(FYI, "offset %lld len %lld", offset, len);

        fsctl_buf.FileOffset = cpu_to_le64(offset);
        fsctl_buf.BeyondFinalZero = cpu_to_le64(offset + len);

        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid, FSCTL_SET_ZERO_DATA,
                        true /* is_fctl */, (char *)&fsctl_buf,
                        sizeof(struct file_zero_data_information), NULL, NULL);
        free_xid(xid);
        return rc;

}

static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
                            loff_t offset, loff_t len)
{
        struct inode *inode;
        struct cifsInodeInfo *cifsi;
        struct cifsFileInfo *cfile = file->private_data;
        struct file_zero_data_information fsctl_buf;
        long rc;
        unsigned int xid;
        __u8 set_sparse = 1;

        xid = get_xid();

        inode = d_inode(cfile->dentry);
        cifsi = CIFS_I(inode);

        /* Need to make file sparse, if not already, before freeing range. */
        /* Consider adding equivalent for compressed since it could also work */
        if (!smb2_set_sparse(xid, tcon, cfile, inode, set_sparse)) {
                rc = -EOPNOTSUPP;
                free_xid(xid);
                return rc;
        }

        cifs_dbg(FYI, "offset %lld len %lld", offset, len);

        fsctl_buf.FileOffset = cpu_to_le64(offset);
        fsctl_buf.BeyondFinalZero = cpu_to_le64(offset + len);

        rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
                        cfile->fid.volatile_fid, FSCTL_SET_ZERO_DATA,
                        true /* is_fctl */, (char *)&fsctl_buf,
                        sizeof(struct file_zero_data_information), NULL, NULL);
        free_xid(xid);
        return rc;
}

static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
                            loff_t off, loff_t len, bool keep_size)
{
        struct inode *inode;
        struct cifsInodeInfo *cifsi;
        struct cifsFileInfo *cfile = file->private_data;
        long rc = -EOPNOTSUPP;
        unsigned int xid;

        xid = get_xid();

        inode = d_inode(cfile->dentry);
        cifsi = CIFS_I(inode);

        /* if file not oplocked can't be sure whether asking to extend size */
        if (!CIFS_CACHE_READ(cifsi))
                if (keep_size == false) {
                        free_xid(xid);
                        return rc;
                }

        /*
         * Files are non-sparse by default so falloc may be a no-op
         * Must check if file sparse. If not sparse, and not extending
         * then no need to do anything since file already allocated
         */
        if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0) {
                if (keep_size == true)
                        rc = 0;
                /* check if extending file */
                else if (i_size_read(inode) >= off + len)
                        /* not extending file and already not sparse */
                        rc = 0;
                /* BB: in future add else clause to extend file */
                else
                        rc = -EOPNOTSUPP;
                free_xid(xid);
                return rc;
        }

        if ((keep_size == true) || (i_size_read(inode) >= off + len)) {
                /*
                 * Check if falloc starts within first few pages of file
                 * and ends within a few pages of the end of file to
                 * ensure that most of file is being forced to be
                 * fallocated now. If so then setting whole file sparse
                 * ie potentially making a few extra pages at the beginning
                 * or end of the file non-sparse via set_sparse is harmless.
                 */
                if ((off > 8192) || (off + len + 8192 < i_size_read(inode))) {
                        rc = -EOPNOTSUPP;
                        free_xid(xid);
                        return rc;
                }

                rc = smb2_set_sparse(xid, tcon, cfile, inode, false);
        }
        /* BB: else ... in future add code to extend file and set sparse */


        free_xid(xid);
        return rc;
}


static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,
                           loff_t off, loff_t len)
{
        /* KEEP_SIZE already checked for by do_fallocate */
        if (mode & FALLOC_FL_PUNCH_HOLE)
                return smb3_punch_hole(file, tcon, off, len);
        else if (mode & FALLOC_FL_ZERO_RANGE) {
                if (mode & FALLOC_FL_KEEP_SIZE)
                        return smb3_zero_range(file, tcon, off, len, true);
                return smb3_zero_range(file, tcon, off, len, false);
        } else if (mode == FALLOC_FL_KEEP_SIZE)
                return smb3_simple_falloc(file, tcon, off, len, true);
        else if (mode == 0)
                return smb3_simple_falloc(file, tcon, off, len, false);

        return -EOPNOTSUPP;
}

static void
smb2_downgrade_oplock(struct TCP_Server_Info *server,
                        struct cifsInodeInfo *cinode, bool set_level2)
{
        if (set_level2)
                server->ops->set_oplock_level(cinode, SMB2_OPLOCK_LEVEL_II,
                                                0, NULL);
        else
                server->ops->set_oplock_level(cinode, 0, 0, NULL);
}

static void
smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
                      unsigned int epoch, bool *purge_cache)
{
        oplock &= 0xFF;
        if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
                return;
        if (oplock == SMB2_OPLOCK_LEVEL_BATCH) {
                cinode->oplock = CIFS_CACHE_RHW_FLG;
                cifs_dbg(FYI, "Batch Oplock granted on inode %p\n",
                         &cinode->vfs_inode);
        } else if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE) {
                cinode->oplock = CIFS_CACHE_RW_FLG;
                cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
                         &cinode->vfs_inode);
        } else if (oplock == SMB2_OPLOCK_LEVEL_II) {
                cinode->oplock = CIFS_CACHE_READ_FLG;
                cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
                         &cinode->vfs_inode);
        } else
                cinode->oplock = 0;
}

static void
smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
                       unsigned int epoch, bool *purge_cache)
{
        char message[5] = {0};

        oplock &= 0xFF;
        if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
                return;

        cinode->oplock = 0;
        if (oplock & SMB2_LEASE_READ_CACHING_HE) {
                cinode->oplock |= CIFS_CACHE_READ_FLG;
                strcat(message, "R");
        }
        if (oplock & SMB2_LEASE_HANDLE_CACHING_HE) {
                cinode->oplock |= CIFS_CACHE_HANDLE_FLG;
                strcat(message, "H");
        }
        if (oplock & SMB2_LEASE_WRITE_CACHING_HE) {
                cinode->oplock |= CIFS_CACHE_WRITE_FLG;
                strcat(message, "W");
        }
        if (!cinode->oplock)
                strcat(message, "None");
        cifs_dbg(FYI, "%s Lease granted on inode %p\n", message,
                 &cinode->vfs_inode);
}

static void
smb3_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
                      unsigned int epoch, bool *purge_cache)
{
        unsigned int old_oplock = cinode->oplock;

        smb21_set_oplock_level(cinode, oplock, epoch, purge_cache);

        if (purge_cache) {
                *purge_cache = false;
                if (old_oplock == CIFS_CACHE_READ_FLG) {
                        if (cinode->oplock == CIFS_CACHE_READ_FLG &&
                            (epoch - cinode->epoch > 0))
                                *purge_cache = true;
                        else if (cinode->oplock == CIFS_CACHE_RH_FLG &&
                                 (epoch - cinode->epoch > 1))
                                *purge_cache = true;
                        else if (cinode->oplock == CIFS_CACHE_RHW_FLG &&
                                 (epoch - cinode->epoch > 1))
                                *purge_cache = true;
                        else if (cinode->oplock == 0 &&
                                 (epoch - cinode->epoch > 0))
                                *purge_cache = true;
                } else if (old_oplock == CIFS_CACHE_RH_FLG) {
                        if (cinode->oplock == CIFS_CACHE_RH_FLG &&
                            (epoch - cinode->epoch > 0))
                                *purge_cache = true;
                        else if (cinode->oplock == CIFS_CACHE_RHW_FLG &&
                                 (epoch - cinode->epoch > 1))
                                *purge_cache = true;
                }
                cinode->epoch = epoch;
        }
}

static bool
smb2_is_read_op(__u32 oplock)
{
        return oplock == SMB2_OPLOCK_LEVEL_II;
}

static bool
smb21_is_read_op(__u32 oplock)
{
        return (oplock & SMB2_LEASE_READ_CACHING_HE) &&
               !(oplock & SMB2_LEASE_WRITE_CACHING_HE);
}

static __le32
map_oplock_to_lease(u8 oplock)
{
        if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE)
                return SMB2_LEASE_WRITE_CACHING | SMB2_LEASE_READ_CACHING;
        else if (oplock == SMB2_OPLOCK_LEVEL_II)
                return SMB2_LEASE_READ_CACHING;
        else if (oplock == SMB2_OPLOCK_LEVEL_BATCH)
                return SMB2_LEASE_HANDLE_CACHING | SMB2_LEASE_READ_CACHING |
                       SMB2_LEASE_WRITE_CACHING;
        return 0;
}

static char *
smb2_create_lease_buf(u8 *lease_key, u8 oplock)
{
        struct create_lease *buf;

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

        memcpy(&buf->lcontext.LeaseKey, lease_key, SMB2_LEASE_KEY_SIZE);
        buf->lcontext.LeaseState = map_oplock_to_lease(oplock);

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_lease, lcontext));
        buf->ccontext.DataLength = cpu_to_le32(sizeof(struct lease_context));
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_lease, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_REQUEST_LEASE is "RqLs" */
        buf->Name[0] = 'R';
        buf->Name[1] = 'q';
        buf->Name[2] = 'L';
        buf->Name[3] = 's';
        return (char *)buf;
}

static char *
smb3_create_lease_buf(u8 *lease_key, u8 oplock)
{
        struct create_lease_v2 *buf;

        buf = kzalloc(sizeof(struct create_lease_v2), GFP_KERNEL);
        if (!buf)
                return NULL;

        memcpy(&buf->lcontext.LeaseKey, lease_key, SMB2_LEASE_KEY_SIZE);
        buf->lcontext.LeaseState = map_oplock_to_lease(oplock);

        buf->ccontext.DataOffset = cpu_to_le16(offsetof
                                        (struct create_lease_v2, lcontext));
        buf->ccontext.DataLength = cpu_to_le32(sizeof(struct lease_context_v2));
        buf->ccontext.NameOffset = cpu_to_le16(offsetof
                                (struct create_lease_v2, Name));
        buf->ccontext.NameLength = cpu_to_le16(4);
        /* SMB2_CREATE_REQUEST_LEASE is "RqLs" */
        buf->Name[0] = 'R';
        buf->Name[1] = 'q';
        buf->Name[2] = 'L';
        buf->Name[3] = 's';
        return (char *)buf;
}

static __u8
smb2_parse_lease_buf(void *buf, unsigned int *epoch, char *lease_key)
{
        struct create_lease *lc = (struct create_lease *)buf;

        *epoch = 0; /* not used */
        if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
                return SMB2_OPLOCK_LEVEL_NOCHANGE;
        return le32_to_cpu(lc->lcontext.LeaseState);
}

static __u8
smb3_parse_lease_buf(void *buf, unsigned int *epoch, char *lease_key)
{
        struct create_lease_v2 *lc = (struct create_lease_v2 *)buf;

        *epoch = le16_to_cpu(lc->lcontext.Epoch);
        if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
                return SMB2_OPLOCK_LEVEL_NOCHANGE;
        if (lease_key)
                memcpy(lease_key, &lc->lcontext.LeaseKey, SMB2_LEASE_KEY_SIZE);
        return le32_to_cpu(lc->lcontext.LeaseState);
}

static unsigned int
smb2_wp_retry_size(struct inode *inode)
{
        return min_t(unsigned int, CIFS_SB(inode->i_sb)->wsize,
                     SMB2_MAX_BUFFER_SIZE);
}

static bool
smb2_dir_needs_close(struct cifsFileInfo *cfile)
{
        return !cfile->invalidHandle;
}

static void
fill_transform_hdr(struct smb2_transform_hdr *tr_hdr, unsigned int orig_len,
                   struct smb_rqst *old_rq)
{
        struct smb2_sync_hdr *shdr =
                        (struct smb2_sync_hdr *)old_rq->rq_iov[0].iov_base;

        memset(tr_hdr, 0, sizeof(struct smb2_transform_hdr));
        tr_hdr->ProtocolId = SMB2_TRANSFORM_PROTO_NUM;
        tr_hdr->OriginalMessageSize = cpu_to_le32(orig_len);
        tr_hdr->Flags = cpu_to_le16(0x01);
        get_random_bytes(&tr_hdr->Nonce, SMB3_AES128CMM_NONCE);
        memcpy(&tr_hdr->SessionId, &shdr->SessionId, 8);
}

/* We can not use the normal sg_set_buf() as we will sometimes pass a
 * stack object as buf.
 */
static inline void smb2_sg_set_buf(struct scatterlist *sg, const void *buf,
                                   unsigned int buflen)
{
        sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
}

/* Assumes:
 * rqst->rq_iov[0]  is transform header
 * rqst->rq_iov[1+] data to be encrypted/decrypted
 */
static struct scatterlist *
init_sg(struct smb_rqst *rqst, u8 *sign)
{
        unsigned int sg_len = rqst->rq_nvec + rqst->rq_npages + 1;
        unsigned int assoc_data_len = sizeof(struct smb2_transform_hdr) - 20;
        struct scatterlist *sg;
        unsigned int i;
        unsigned int j;

        sg = kmalloc_array(sg_len, sizeof(struct scatterlist), GFP_KERNEL);
        if (!sg)
                return NULL;

        sg_init_table(sg, sg_len);
        smb2_sg_set_buf(&sg[0], rqst->rq_iov[0].iov_base + 20, assoc_data_len);
        for (i = 1; i < rqst->rq_nvec; i++)
                smb2_sg_set_buf(&sg[i], rqst->rq_iov[i].iov_base,
                                                rqst->rq_iov[i].iov_len);
        for (j = 0; i < sg_len - 1; i++, j++) {
                unsigned int len, offset;

                rqst_page_get_length(rqst, j, &len, &offset);
                sg_set_page(&sg[i], rqst->rq_pages[j], len, offset);
        }
        smb2_sg_set_buf(&sg[sg_len - 1], sign, SMB2_SIGNATURE_SIZE);
        return sg;
}

static int
smb2_get_enc_key(struct TCP_Server_Info *server, __u64 ses_id, int enc, u8 *key)
{
        struct cifs_ses *ses;
        u8 *ses_enc_key;

        spin_lock(&cifs_tcp_ses_lock);
        list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
                if (ses->Suid != ses_id)
                        continue;
                ses_enc_key = enc ? ses->smb3encryptionkey :
                                                        ses->smb3decryptionkey;
                memcpy(key, ses_enc_key, SMB3_SIGN_KEY_SIZE);
                spin_unlock(&cifs_tcp_ses_lock);
                return 0;
        }
        spin_unlock(&cifs_tcp_ses_lock);

        return 1;
}
/*
 * Encrypt or decrypt @rqst message. @rqst[0] has the following format:
 * iov[0]   - transform header (associate data),
 * iov[1-N] - SMB2 header and pages - data to encrypt.
 * On success return encrypted data in iov[1-N] and pages, leave iov[0]
 * untouched.
 */
static int
crypt_message(struct TCP_Server_Info *server, struct smb_rqst *rqst, int enc)
{
        struct smb2_transform_hdr *tr_hdr =
                        (struct smb2_transform_hdr *)rqst->rq_iov[0].iov_base;
        unsigned int assoc_data_len = sizeof(struct smb2_transform_hdr) - 20;
        int rc = 0;
        struct scatterlist *sg;
        u8 sign[SMB2_SIGNATURE_SIZE] = {};
        u8 key[SMB3_SIGN_KEY_SIZE];
        struct aead_request *req;
        char *iv;
        unsigned int iv_len;
        DECLARE_CRYPTO_WAIT(wait);
        struct crypto_aead *tfm;
        unsigned int crypt_len = le32_to_cpu(tr_hdr->OriginalMessageSize);

        rc = smb2_get_enc_key(server, tr_hdr->SessionId, enc, key);
        if (rc) {
                cifs_dbg(VFS, "%s: Could not get %scryption key\n", __func__,
                         enc ? "en" : "de");
                return 0;
        }

        rc = smb3_crypto_aead_allocate(server);
        if (rc) {
                cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
                return rc;
        }

        tfm = enc ? server->secmech.ccmaesencrypt :
                                                server->secmech.ccmaesdecrypt;
        rc = crypto_aead_setkey(tfm, key, SMB3_SIGN_KEY_SIZE);
        if (rc) {
                cifs_dbg(VFS, "%s: Failed to set aead key %d\n", __func__, rc);
                return rc;
        }

        rc = crypto_aead_setauthsize(tfm, SMB2_SIGNATURE_SIZE);
        if (rc) {
                cifs_dbg(VFS, "%s: Failed to set authsize %d\n", __func__, rc);
                return rc;
        }

        req = aead_request_alloc(tfm, GFP_KERNEL);
        if (!req) {
                cifs_dbg(VFS, "%s: Failed to alloc aead request", __func__);
                return -ENOMEM;
        }

        if (!enc) {
                memcpy(sign, &tr_hdr->Signature, SMB2_SIGNATURE_SIZE);
                crypt_len += SMB2_SIGNATURE_SIZE;
        }

        sg = init_sg(rqst, sign);
        if (!sg) {
                cifs_dbg(VFS, "%s: Failed to init sg", __func__);
                rc = -ENOMEM;
                goto free_req;
        }

        iv_len = crypto_aead_ivsize(tfm);
        iv = kzalloc(iv_len, GFP_KERNEL);
        if (!iv) {
                cifs_dbg(VFS, "%s: Failed to alloc IV", __func__);
                rc = -ENOMEM;
                goto free_sg;
        }
        iv[0] = 3;
        memcpy(iv + 1, (char *)tr_hdr->Nonce, SMB3_AES128CMM_NONCE);

        aead_request_set_crypt(req, sg, sg, crypt_len, iv);
        aead_request_set_ad(req, assoc_data_len);

        aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
                                  crypto_req_done, &wait);

        rc = crypto_wait_req(enc ? crypto_aead_encrypt(req)
                                : crypto_aead_decrypt(req), &wait);

        if (!rc && enc)
                memcpy(&tr_hdr->Signature, sign, SMB2_SIGNATURE_SIZE);

        kfree(iv);
free_sg:
        kfree(sg);
free_req:
        kfree(req);
        return rc;
}

static int
smb3_init_transform_rq(struct TCP_Server_Info *server, struct smb_rqst *new_rq,
                       struct smb_rqst *old_rq)
{
        struct kvec *iov;
        struct page **pages;
        struct smb2_transform_hdr *tr_hdr;
        unsigned int npages = old_rq->rq_npages;
        unsigned int orig_len;
        int i;
        int rc = -ENOMEM;

        pages = kmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
        if (!pages)
                return rc;

        new_rq->rq_pages = pages;
        new_rq->rq_offset = old_rq->rq_offset;
        new_rq->rq_npages = old_rq->rq_npages;
        new_rq->rq_pagesz = old_rq->rq_pagesz;
        new_rq->rq_tailsz = old_rq->rq_tailsz;

        for (i = 0; i < npages; i++) {
                pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
                if (!pages[i])
                        goto err_free_pages;
        }

        iov = kmalloc_array(old_rq->rq_nvec + 1, sizeof(struct kvec),
                            GFP_KERNEL);
        if (!iov)
                goto err_free_pages;

        /* copy all iovs from the old */
        memcpy(&iov[1], &old_rq->rq_iov[0],
                                sizeof(struct kvec) * old_rq->rq_nvec);

        new_rq->rq_iov = iov;
        new_rq->rq_nvec = old_rq->rq_nvec + 1;

        tr_hdr = kmalloc(sizeof(struct smb2_transform_hdr), GFP_KERNEL);
        if (!tr_hdr)
                goto err_free_iov;

        orig_len = smb_rqst_len(server, old_rq);

        /* fill the 2nd iov with a transform header */
        fill_transform_hdr(tr_hdr, orig_len, old_rq);
        new_rq->rq_iov[0].iov_base = tr_hdr;
        new_rq->rq_iov[0].iov_len = sizeof(struct smb2_transform_hdr);

        /* copy pages form the old */
        for (i = 0; i < npages; i++) {
                char *dst, *src;
                unsigned int offset, len;

                rqst_page_get_length(new_rq, i, &len, &offset);

                dst = (char *) kmap(new_rq->rq_pages[i]) + offset;
                src = (char *) kmap(old_rq->rq_pages[i]) + offset;

                memcpy(dst, src, len);
                kunmap(new_rq->rq_pages[i]);
                kunmap(old_rq->rq_pages[i]);
        }

        rc = crypt_message(server, new_rq, 1);
        cifs_dbg(FYI, "encrypt message returned %d", rc);
        if (rc)
                goto err_free_tr_hdr;

        return rc;

err_free_tr_hdr:
        kfree(tr_hdr);
err_free_iov:
        kfree(iov);
err_free_pages:
        for (i = i - 1; i >= 0; i--)
                put_page(pages[i]);
        kfree(pages);
        return rc;
}

static void
smb3_free_transform_rq(struct smb_rqst *rqst)
{
        int i = rqst->rq_npages - 1;

        for (; i >= 0; i--)
                put_page(rqst->rq_pages[i]);
        kfree(rqst->rq_pages);
        /* free transform header */
        kfree(rqst->rq_iov[0].iov_base);
        kfree(rqst->rq_iov);
}

static int
smb3_is_transform_hdr(void *buf)
{
        struct smb2_transform_hdr *trhdr = buf;

        return trhdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM;
}

static int
decrypt_raw_data(struct TCP_Server_Info *server, char *buf,
                 unsigned int buf_data_size, struct page **pages,
                 unsigned int npages, unsigned int page_data_size)
{
        struct kvec iov[2];
        struct smb_rqst rqst = {NULL};
        int rc;

        iov[0].iov_base = buf;
        iov[0].iov_len = sizeof(struct smb2_transform_hdr);
        iov[1].iov_base = buf + sizeof(struct smb2_transform_hdr);
        iov[1].iov_len = buf_data_size;

        rqst.rq_iov = iov;
        rqst.rq_nvec = 2;
        rqst.rq_pages = pages;
        rqst.rq_npages = npages;
        rqst.rq_pagesz = PAGE_SIZE;
        rqst.rq_tailsz = (page_data_size % PAGE_SIZE) ? : PAGE_SIZE;

        rc = crypt_message(server, &rqst, 0);
        cifs_dbg(FYI, "decrypt message returned %d\n", rc);

        if (rc)
                return rc;

        memmove(buf, iov[1].iov_base, buf_data_size);

        server->total_read = buf_data_size + page_data_size;

        return rc;
}

static int
read_data_into_pages(struct TCP_Server_Info *server, struct page **pages,
                     unsigned int npages, unsigned int len)
{
        int i;
        int length;

        for (i = 0; i < npages; i++) {
                struct page *page = pages[i];
                size_t n;

                n = len;
                if (len >= PAGE_SIZE) {
                        /* enough data to fill the page */
                        n = PAGE_SIZE;
                        len -= n;
                } else {
                        zero_user(page, len, PAGE_SIZE - len);
                        len = 0;
                }
                length = cifs_read_page_from_socket(server, page, 0, n);
                if (length < 0)
                        return length;
                server->total_read += length;
        }

        return 0;
}

static int
init_read_bvec(struct page **pages, unsigned int npages, unsigned int data_size,
               unsigned int cur_off, struct bio_vec **page_vec)
{
        struct bio_vec *bvec;
        int i;

        bvec = kcalloc(npages, sizeof(struct bio_vec), GFP_KERNEL);
        if (!bvec)
                return -ENOMEM;

        for (i = 0; i < npages; i++) {
                bvec[i].bv_page = pages[i];
                bvec[i].bv_offset = (i == 0) ? cur_off : 0;
                bvec[i].bv_len = min_t(unsigned int, PAGE_SIZE, data_size);
                data_size -= bvec[i].bv_len;
        }

        if (data_size != 0) {
                cifs_dbg(VFS, "%s: something went wrong\n", __func__);
                kfree(bvec);
                return -EIO;
        }

        *page_vec = bvec;
        return 0;
}

static int
handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
                 char *buf, unsigned int buf_len, struct page **pages,
                 unsigned int npages, unsigned int page_data_size)
{
        unsigned int data_offset;
        unsigned int data_len;
        unsigned int cur_off;
        unsigned int cur_page_idx;
        unsigned int pad_len;
        struct cifs_readdata *rdata = mid->callback_data;
        struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buf;
        struct bio_vec *bvec = NULL;
        struct iov_iter iter;
        struct kvec iov;
        int length;
        bool use_rdma_mr = false;

        if (shdr->Command != SMB2_READ) {
                cifs_dbg(VFS, "only big read responses are supported\n");
                return -ENOTSUPP;
        }

        if (server->ops->is_session_expired &&
            server->ops->is_session_expired(buf)) {
                cifs_reconnect(server);
                wake_up(&server->response_q);
                return -1;
        }

        if (server->ops->is_status_pending &&
                        server->ops->is_status_pending(buf, server, 0))
                return -1;

        rdata->result = server->ops->map_error(buf, false);
        if (rdata->result != 0) {
                cifs_dbg(FYI, "%s: server returned error %d\n",
                         __func__, rdata->result);
                dequeue_mid(mid, rdata->result);
                return 0;
        }

        data_offset = server->ops->read_data_offset(buf);
#ifdef CONFIG_CIFS_SMB_DIRECT
        use_rdma_mr = rdata->mr;
#endif
        data_len = server->ops->read_data_length(buf, use_rdma_mr);

        if (data_offset < server->vals->read_rsp_size) {
                /*
                 * win2k8 sometimes sends an offset of 0 when the read
                 * is beyond the EOF. Treat it as if the data starts just after
                 * the header.
                 */
                cifs_dbg(FYI, "%s: data offset (%u) inside read response header\n",
                         __func__, data_offset);
                data_offset = server->vals->read_rsp_size;
        } else if (data_offset > MAX_CIFS_SMALL_BUFFER_SIZE) {
                /* data_offset is beyond the end of smallbuf */
                cifs_dbg(FYI, "%s: data offset (%u) beyond end of smallbuf\n",
                         __func__, data_offset);
                rdata->result = -EIO;
                dequeue_mid(mid, rdata->result);
                return 0;
        }

        pad_len = data_offset - server->vals->read_rsp_size;

        if (buf_len <= data_offset) {
                /* read response payload is in pages */
                cur_page_idx = pad_len / PAGE_SIZE;
                cur_off = pad_len % PAGE_SIZE;

                if (cur_page_idx != 0) {
                        /* data offset is beyond the 1st page of response */
                        cifs_dbg(FYI, "%s: data offset (%u) beyond 1st page of response\n",
                                 __func__, data_offset);
                        rdata->result = -EIO;
                        dequeue_mid(mid, rdata->result);
                        return 0;
                }

                if (data_len > page_data_size - pad_len) {
                        /* data_len is corrupt -- discard frame */
                        rdata->result = -EIO;
                        dequeue_mid(mid, rdata->result);
                        return 0;
                }

                rdata->result = init_read_bvec(pages, npages, page_data_size,
                                               cur_off, &bvec);
                if (rdata->result != 0) {
                        dequeue_mid(mid, rdata->result);
                        return 0;
                }

                iov_iter_bvec(&iter, WRITE | ITER_BVEC, bvec, npages, data_len);
        } else if (buf_len >= data_offset + data_len) {
                /* read response payload is in buf */
                WARN_ONCE(npages > 0, "read data can be either in buf or in pages");
                iov.iov_base = buf + data_offset;
                iov.iov_len = data_len;
                iov_iter_kvec(&iter, WRITE | ITER_KVEC, &iov, 1, data_len);
        } else {
                /* read response payload cannot be in both buf and pages */
                WARN_ONCE(1, "buf can not contain only a part of read data");
                rdata->result = -EIO;
                dequeue_mid(mid, rdata->result);
                return 0;
        }

        /* set up first iov for signature check */
        rdata->iov[0].iov_base = buf;
        rdata->iov[0].iov_len = 4;
        rdata->iov[1].iov_base = buf + 4;
        rdata->iov[1].iov_len = server->vals->read_rsp_size - 4;
        cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n",
                 rdata->iov[0].iov_base, server->vals->read_rsp_size);

        length = rdata->copy_into_pages(server, rdata, &iter);

        kfree(bvec);

        if (length < 0)
                return length;

        dequeue_mid(mid, false);
        return length;
}

static int
receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid)
{
        char *buf = server->smallbuf;
        struct smb2_transform_hdr *tr_hdr = (struct smb2_transform_hdr *)buf;
        unsigned int npages;
        struct page **pages;
        unsigned int len;
        unsigned int buflen = server->pdu_size;
        int rc;
        int i = 0;

        len = min_t(unsigned int, buflen, server->vals->read_rsp_size +
                sizeof(struct smb2_transform_hdr)) - HEADER_SIZE(server) + 1;

        rc = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1, len);
        if (rc < 0)
                return rc;
        server->total_read += rc;

        len = le32_to_cpu(tr_hdr->OriginalMessageSize) -
                server->vals->read_rsp_size;
        npages = DIV_ROUND_UP(len, PAGE_SIZE);

        pages = kmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
        if (!pages) {
                rc = -ENOMEM;
                goto discard_data;
        }

        for (; i < npages; i++) {
                pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
                if (!pages[i]) {
                        rc = -ENOMEM;
                        goto discard_data;
                }
        }

        /* read read data into pages */
        rc = read_data_into_pages(server, pages, npages, len);
        if (rc)
                goto free_pages;

        rc = cifs_discard_remaining_data(server);
        if (rc)
                goto free_pages;

        rc = decrypt_raw_data(server, buf, server->vals->read_rsp_size,
                              pages, npages, len);
        if (rc)
                goto free_pages;

        *mid = smb2_find_mid(server, buf);
        if (*mid == NULL)
                cifs_dbg(FYI, "mid not found\n");
        else {
                cifs_dbg(FYI, "mid found\n");
                (*mid)->decrypted = true;
                rc = handle_read_data(server, *mid, buf,
                                      server->vals->read_rsp_size,
                                      pages, npages, len);
        }

free_pages:
        for (i = i - 1; i >= 0; i--)
                put_page(pages[i]);
        kfree(pages);
        return rc;
discard_data:
        cifs_discard_remaining_data(server);
        goto free_pages;
}

static int
receive_encrypted_standard(struct TCP_Server_Info *server,
                           struct mid_q_entry **mid)
{
        int length;
        char *buf = server->smallbuf;
        unsigned int pdu_length = server->pdu_size;
        unsigned int buf_size;
        struct mid_q_entry *mid_entry;

        /* switch to large buffer if too big for a small one */
        if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE) {
                server->large_buf = true;
                memcpy(server->bigbuf, buf, server->total_read);
                buf = server->bigbuf;
        }

        /* now read the rest */
        length = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1,
                                pdu_length - HEADER_SIZE(server) + 1);
        if (length < 0)
                return length;
        server->total_read += length;

        buf_size = pdu_length - sizeof(struct smb2_transform_hdr);
        length = decrypt_raw_data(server, buf, buf_size, NULL, 0, 0);
        if (length)
                return length;

        mid_entry = smb2_find_mid(server, buf);
        if (mid_entry == NULL)
                cifs_dbg(FYI, "mid not found\n");
        else {
                cifs_dbg(FYI, "mid found\n");
                mid_entry->decrypted = true;
        }

        *mid = mid_entry;

        if (mid_entry && mid_entry->handle)
                return mid_entry->handle(server, mid_entry);

        return cifs_handle_standard(server, mid_entry);
}

static int
smb3_receive_transform(struct TCP_Server_Info *server, struct mid_q_entry **mid)
{
        char *buf = server->smallbuf;
        unsigned int pdu_length = server->pdu_size;
        struct smb2_transform_hdr *tr_hdr = (struct smb2_transform_hdr *)buf;
        unsigned int orig_len = le32_to_cpu(tr_hdr->OriginalMessageSize);

        if (pdu_length < sizeof(struct smb2_transform_hdr) +
                                                sizeof(struct smb2_sync_hdr)) {
                cifs_dbg(VFS, "Transform message is too small (%u)\n",
                         pdu_length);
                cifs_reconnect(server);
                wake_up(&server->response_q);
                return -ECONNABORTED;
        }

        if (pdu_length < orig_len + sizeof(struct smb2_transform_hdr)) {
                cifs_dbg(VFS, "Transform message is broken\n");
                cifs_reconnect(server);
                wake_up(&server->response_q);
                return -ECONNABORTED;
        }

        if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server))
                return receive_encrypted_read(server, mid);

        return receive_encrypted_standard(server, mid);
}

int
smb3_handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid)
{
        char *buf = server->large_buf ? server->bigbuf : server->smallbuf;

        return handle_read_data(server, mid, buf, server->pdu_size,
                                NULL, 0, 0);
}

static int
smb2_next_header(char *buf)
{
        struct smb2_sync_hdr *hdr = (struct smb2_sync_hdr *)buf;
        struct smb2_transform_hdr *t_hdr = (struct smb2_transform_hdr *)buf;

        if (hdr->ProtocolId == SMB2_TRANSFORM_PROTO_NUM)