linux/fs/cifs/smb2misc.c
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   1/*
   2 *   fs/cifs/smb2misc.c
   3 *
   4 *   Copyright (C) International Business Machines  Corp., 2002,2011
   5 *                 Etersoft, 2012
   6 *   Author(s): Steve French (sfrench@us.ibm.com)
   7 *              Pavel Shilovsky (pshilovsky@samba.org) 2012
   8 *
   9 *   This library is free software; you can redistribute it and/or modify
  10 *   it under the terms of the GNU Lesser General Public License as published
  11 *   by the Free Software Foundation; either version 2.1 of the License, or
  12 *   (at your option) any later version.
  13 *
  14 *   This library is distributed in the hope that it will be useful,
  15 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  17 *   the GNU Lesser General Public License for more details.
  18 *
  19 *   You should have received a copy of the GNU Lesser General Public License
  20 *   along with this library; if not, write to the Free Software
  21 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  22 */
  23#include <linux/ctype.h>
  24#include "smb2pdu.h"
  25#include "cifsglob.h"
  26#include "cifsproto.h"
  27#include "smb2proto.h"
  28#include "cifs_debug.h"
  29#include "cifs_unicode.h"
  30#include "smb2status.h"
  31
  32static int
  33check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
  34{
  35        /*
  36         * Make sure that this really is an SMB, that it is a response,
  37         * and that the message ids match.
  38         */
  39        if ((*(__le32 *)hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
  40            (mid == hdr->MessageId)) {
  41                if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
  42                        return 0;
  43                else {
  44                        /* only one valid case where server sends us request */
  45                        if (hdr->Command == SMB2_OPLOCK_BREAK)
  46                                return 0;
  47                        else
  48                                cifs_dbg(VFS, "Received Request not response\n");
  49                }
  50        } else { /* bad signature or mid */
  51                if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
  52                        cifs_dbg(VFS, "Bad protocol string signature header %x\n",
  53                                 *(unsigned int *) hdr->ProtocolId);
  54                if (mid != hdr->MessageId)
  55                        cifs_dbg(VFS, "Mids do not match: %llu and %llu\n",
  56                                 mid, hdr->MessageId);
  57        }
  58        cifs_dbg(VFS, "Bad SMB detected. The Mid=%llu\n", hdr->MessageId);
  59        return 1;
  60}
  61
  62/*
  63 *  The following table defines the expected "StructureSize" of SMB2 responses
  64 *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS responses.
  65 *
  66 *  Note that commands are defined in smb2pdu.h in le16 but the array below is
  67 *  indexed by command in host byte order
  68 */
  69static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
  70        /* SMB2_NEGOTIATE */ __constant_cpu_to_le16(65),
  71        /* SMB2_SESSION_SETUP */ __constant_cpu_to_le16(9),
  72        /* SMB2_LOGOFF */ __constant_cpu_to_le16(4),
  73        /* SMB2_TREE_CONNECT */ __constant_cpu_to_le16(16),
  74        /* SMB2_TREE_DISCONNECT */ __constant_cpu_to_le16(4),
  75        /* SMB2_CREATE */ __constant_cpu_to_le16(89),
  76        /* SMB2_CLOSE */ __constant_cpu_to_le16(60),
  77        /* SMB2_FLUSH */ __constant_cpu_to_le16(4),
  78        /* SMB2_READ */ __constant_cpu_to_le16(17),
  79        /* SMB2_WRITE */ __constant_cpu_to_le16(17),
  80        /* SMB2_LOCK */ __constant_cpu_to_le16(4),
  81        /* SMB2_IOCTL */ __constant_cpu_to_le16(49),
  82        /* BB CHECK this ... not listed in documentation */
  83        /* SMB2_CANCEL */ __constant_cpu_to_le16(0),
  84        /* SMB2_ECHO */ __constant_cpu_to_le16(4),
  85        /* SMB2_QUERY_DIRECTORY */ __constant_cpu_to_le16(9),
  86        /* SMB2_CHANGE_NOTIFY */ __constant_cpu_to_le16(9),
  87        /* SMB2_QUERY_INFO */ __constant_cpu_to_le16(9),
  88        /* SMB2_SET_INFO */ __constant_cpu_to_le16(2),
  89        /* BB FIXME can also be 44 for lease break */
  90        /* SMB2_OPLOCK_BREAK */ __constant_cpu_to_le16(24)
  91};
  92
  93int
  94smb2_check_message(char *buf, unsigned int length)
  95{
  96        struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
  97        struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
  98        __u64 mid = hdr->MessageId;
  99        __u32 len = get_rfc1002_length(buf);
 100        __u32 clc_len;  /* calculated length */
 101        int command;
 102
 103        /* BB disable following printk later */
 104        cifs_dbg(FYI, "%s length: 0x%x, smb_buf_length: 0x%x\n",
 105                 __func__, length, len);
 106
 107        /*
 108         * Add function to do table lookup of StructureSize by command
 109         * ie Validate the wct via smb2_struct_sizes table above
 110         */
 111
 112        if (length < sizeof(struct smb2_pdu)) {
 113                if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
 114                        pdu->StructureSize2 = 0;
 115                        /*
 116                         * As with SMB/CIFS, on some error cases servers may
 117                         * not return wct properly
 118                         */
 119                        return 0;
 120                } else {
 121                        cifs_dbg(VFS, "Length less than SMB header size\n");
 122                }
 123                return 1;
 124        }
 125        if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
 126                cifs_dbg(VFS, "SMB length greater than maximum, mid=%llu\n",
 127                         mid);
 128                return 1;
 129        }
 130
 131        if (check_smb2_hdr(hdr, mid))
 132                return 1;
 133
 134        if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
 135                cifs_dbg(VFS, "Illegal structure size %u\n",
 136                         le16_to_cpu(hdr->StructureSize));
 137                return 1;
 138        }
 139
 140        command = le16_to_cpu(hdr->Command);
 141        if (command >= NUMBER_OF_SMB2_COMMANDS) {
 142                cifs_dbg(VFS, "Illegal SMB2 command %d\n", command);
 143                return 1;
 144        }
 145
 146        if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
 147                if (command != SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0 ||
 148                    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
 149                        /* error packets have 9 byte structure size */
 150                        cifs_dbg(VFS, "Illegal response size %u for command %d\n",
 151                                 le16_to_cpu(pdu->StructureSize2), command);
 152                        return 1;
 153                } else if (command == SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0)
 154                           && (le16_to_cpu(pdu->StructureSize2) != 44)
 155                           && (le16_to_cpu(pdu->StructureSize2) != 36)) {
 156                        /* special case for SMB2.1 lease break message */
 157                        cifs_dbg(VFS, "Illegal response size %d for oplock break\n",
 158                                 le16_to_cpu(pdu->StructureSize2));
 159                        return 1;
 160                }
 161        }
 162
 163        if (4 + len != length) {
 164                cifs_dbg(VFS, "Total length %u RFC1002 length %u mismatch mid %llu\n",
 165                         length, 4 + len, mid);
 166                return 1;
 167        }
 168
 169        clc_len = smb2_calc_size(hdr);
 170
 171        if (4 + len != clc_len) {
 172                cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
 173                         clc_len, 4 + len, mid);
 174                /* create failed on symlink */
 175                if (command == SMB2_CREATE_HE &&
 176                    hdr->Status == STATUS_STOPPED_ON_SYMLINK)
 177                        return 0;
 178                /* Windows 7 server returns 24 bytes more */
 179                if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
 180                        return 0;
 181                /* server can return one byte more */
 182                if (clc_len == 4 + len + 1)
 183                        return 0;
 184                return 1;
 185        }
 186        return 0;
 187}
 188
 189/*
 190 * The size of the variable area depends on the offset and length fields
 191 * located in different fields for various SMB2 responses. SMB2 responses
 192 * with no variable length info, show an offset of zero for the offset field.
 193 */
 194static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
 195        /* SMB2_NEGOTIATE */ true,
 196        /* SMB2_SESSION_SETUP */ true,
 197        /* SMB2_LOGOFF */ false,
 198        /* SMB2_TREE_CONNECT */ false,
 199        /* SMB2_TREE_DISCONNECT */ false,
 200        /* SMB2_CREATE */ true,
 201        /* SMB2_CLOSE */ false,
 202        /* SMB2_FLUSH */ false,
 203        /* SMB2_READ */ true,
 204        /* SMB2_WRITE */ false,
 205        /* SMB2_LOCK */ false,
 206        /* SMB2_IOCTL */ true,
 207        /* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
 208        /* SMB2_ECHO */ false,
 209        /* SMB2_QUERY_DIRECTORY */ true,
 210        /* SMB2_CHANGE_NOTIFY */ true,
 211        /* SMB2_QUERY_INFO */ true,
 212        /* SMB2_SET_INFO */ false,
 213        /* SMB2_OPLOCK_BREAK */ false
 214};
 215
 216/*
 217 * Returns the pointer to the beginning of the data area. Length of the data
 218 * area and the offset to it (from the beginning of the smb are also returned.
 219 */
 220char *
 221smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
 222{
 223        *off = 0;
 224        *len = 0;
 225
 226        /* error responses do not have data area */
 227        if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
 228            (((struct smb2_err_rsp *)hdr)->StructureSize) ==
 229                                                SMB2_ERROR_STRUCTURE_SIZE2)
 230                return NULL;
 231
 232        /*
 233         * Following commands have data areas so we have to get the location
 234         * of the data buffer offset and data buffer length for the particular
 235         * command.
 236         */
 237        switch (hdr->Command) {
 238        case SMB2_NEGOTIATE:
 239                *off = le16_to_cpu(
 240                    ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferOffset);
 241                *len = le16_to_cpu(
 242                    ((struct smb2_negotiate_rsp *)hdr)->SecurityBufferLength);
 243                break;
 244        case SMB2_SESSION_SETUP:
 245                *off = le16_to_cpu(
 246                    ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferOffset);
 247                *len = le16_to_cpu(
 248                    ((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferLength);
 249                break;
 250        case SMB2_CREATE:
 251                *off = le32_to_cpu(
 252                    ((struct smb2_create_rsp *)hdr)->CreateContextsOffset);
 253                *len = le32_to_cpu(
 254                    ((struct smb2_create_rsp *)hdr)->CreateContextsLength);
 255                break;
 256        case SMB2_QUERY_INFO:
 257                *off = le16_to_cpu(
 258                    ((struct smb2_query_info_rsp *)hdr)->OutputBufferOffset);
 259                *len = le32_to_cpu(
 260                    ((struct smb2_query_info_rsp *)hdr)->OutputBufferLength);
 261                break;
 262        case SMB2_READ:
 263                *off = ((struct smb2_read_rsp *)hdr)->DataOffset;
 264                *len = le32_to_cpu(((struct smb2_read_rsp *)hdr)->DataLength);
 265                break;
 266        case SMB2_QUERY_DIRECTORY:
 267                *off = le16_to_cpu(
 268                  ((struct smb2_query_directory_rsp *)hdr)->OutputBufferOffset);
 269                *len = le32_to_cpu(
 270                  ((struct smb2_query_directory_rsp *)hdr)->OutputBufferLength);
 271                break;
 272        case SMB2_IOCTL:
 273                *off = le32_to_cpu(
 274                  ((struct smb2_ioctl_rsp *)hdr)->OutputOffset);
 275                *len = le32_to_cpu(((struct smb2_ioctl_rsp *)hdr)->OutputCount);
 276                break;
 277        case SMB2_CHANGE_NOTIFY:
 278        default:
 279                /* BB FIXME for unimplemented cases above */
 280                cifs_dbg(VFS, "no length check for command\n");
 281                break;
 282        }
 283
 284        /*
 285         * Invalid length or offset probably means data area is invalid, but
 286         * we have little choice but to ignore the data area in this case.
 287         */
 288        if (*off > 4096) {
 289                cifs_dbg(VFS, "offset %d too large, data area ignored\n", *off);
 290                *len = 0;
 291                *off = 0;
 292        } else if (*off < 0) {
 293                cifs_dbg(VFS, "negative offset %d to data invalid ignore data area\n",
 294                         *off);
 295                *off = 0;
 296                *len = 0;
 297        } else if (*len < 0) {
 298                cifs_dbg(VFS, "negative data length %d invalid, data area ignored\n",
 299                         *len);
 300                *len = 0;
 301        } else if (*len > 128 * 1024) {
 302                cifs_dbg(VFS, "data area larger than 128K: %d\n", *len);
 303                *len = 0;
 304        }
 305
 306        /* return pointer to beginning of data area, ie offset from SMB start */
 307        if ((*off != 0) && (*len != 0))
 308                return hdr->ProtocolId + *off;
 309        else
 310                return NULL;
 311}
 312
 313/*
 314 * Calculate the size of the SMB message based on the fixed header
 315 * portion, the number of word parameters and the data portion of the message.
 316 */
 317unsigned int
 318smb2_calc_size(void *buf)
 319{
 320        struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 321        struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
 322        int offset; /* the offset from the beginning of SMB to data area */
 323        int data_length; /* the length of the variable length data area */
 324        /* Structure Size has already been checked to make sure it is 64 */
 325        int len = 4 + le16_to_cpu(pdu->hdr.StructureSize);
 326
 327        /*
 328         * StructureSize2, ie length of fixed parameter area has already
 329         * been checked to make sure it is the correct length.
 330         */
 331        len += le16_to_cpu(pdu->StructureSize2);
 332
 333        if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
 334                goto calc_size_exit;
 335
 336        smb2_get_data_area_len(&offset, &data_length, hdr);
 337        cifs_dbg(FYI, "SMB2 data length %d offset %d\n", data_length, offset);
 338
 339        if (data_length > 0) {
 340                /*
 341                 * Check to make sure that data area begins after fixed area,
 342                 * Note that last byte of the fixed area is part of data area
 343                 * for some commands, typically those with odd StructureSize,
 344                 * so we must add one to the calculation (and 4 to account for
 345                 * the size of the RFC1001 hdr.
 346                 */
 347                if (offset + 4 + 1 < len) {
 348                        cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n",
 349                                 offset + 4 + 1, len);
 350                        data_length = 0;
 351                } else {
 352                        len = 4 + offset + data_length;
 353                }
 354        }
 355calc_size_exit:
 356        cifs_dbg(FYI, "SMB2 len %d\n", len);
 357        return len;
 358}
 359
 360/* Note: caller must free return buffer */
 361__le16 *
 362cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
 363{
 364        int len;
 365        const char *start_of_path;
 366        __le16 *to;
 367
 368        /* Windows doesn't allow paths beginning with \ */
 369        if (from[0] == '\\')
 370                start_of_path = from + 1;
 371        else
 372                start_of_path = from;
 373        to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
 374                                   cifs_sb->local_nls,
 375                                   cifs_sb->mnt_cifs_flags &
 376                                        CIFS_MOUNT_MAP_SPECIAL_CHR);
 377        return to;
 378}
 379
 380__le32
 381smb2_get_lease_state(struct cifsInodeInfo *cinode)
 382{
 383        __le32 lease = 0;
 384
 385        if (CIFS_CACHE_WRITE(cinode))
 386                lease |= SMB2_LEASE_WRITE_CACHING;
 387        if (CIFS_CACHE_HANDLE(cinode))
 388                lease |= SMB2_LEASE_HANDLE_CACHING;
 389        if (CIFS_CACHE_READ(cinode))
 390                lease |= SMB2_LEASE_READ_CACHING;
 391        return lease;
 392}
 393
 394struct smb2_lease_break_work {
 395        struct work_struct lease_break;
 396        struct tcon_link *tlink;
 397        __u8 lease_key[16];
 398        __le32 lease_state;
 399};
 400
 401static void
 402cifs_ses_oplock_break(struct work_struct *work)
 403{
 404        struct smb2_lease_break_work *lw = container_of(work,
 405                                struct smb2_lease_break_work, lease_break);
 406        int rc;
 407
 408        rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
 409                              lw->lease_state);
 410        cifs_dbg(FYI, "Lease release rc %d\n", rc);
 411        cifs_put_tlink(lw->tlink);
 412        kfree(lw);
 413}
 414
 415static bool
 416smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
 417                    struct smb2_lease_break_work *lw)
 418{
 419        bool found;
 420        __u8 lease_state;
 421        struct list_head *tmp;
 422        struct cifsFileInfo *cfile;
 423        struct TCP_Server_Info *server = tcon->ses->server;
 424        struct cifs_pending_open *open;
 425        struct cifsInodeInfo *cinode;
 426        int ack_req = le32_to_cpu(rsp->Flags &
 427                                  SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);
 428
 429        lease_state = le32_to_cpu(rsp->NewLeaseState);
 430
 431        list_for_each(tmp, &tcon->openFileList) {
 432                cfile = list_entry(tmp, struct cifsFileInfo, tlist);
 433                cinode = CIFS_I(cfile->dentry->d_inode);
 434
 435                if (memcmp(cinode->lease_key, rsp->LeaseKey,
 436                                                        SMB2_LEASE_KEY_SIZE))
 437                        continue;
 438
 439                cifs_dbg(FYI, "found in the open list\n");
 440                cifs_dbg(FYI, "lease key match, lease break 0x%d\n",
 441                         le32_to_cpu(rsp->NewLeaseState));
 442
 443                server->ops->set_oplock_level(cinode, lease_state, 0, NULL);
 444
 445                if (ack_req)
 446                        cfile->oplock_break_cancelled = false;
 447                else
 448                        cfile->oplock_break_cancelled = true;
 449
 450                queue_work(cifsiod_wq, &cfile->oplock_break);
 451                kfree(lw);
 452                return true;
 453        }
 454
 455        found = false;
 456        list_for_each_entry(open, &tcon->pending_opens, olist) {
 457                if (memcmp(open->lease_key, rsp->LeaseKey,
 458                           SMB2_LEASE_KEY_SIZE))
 459                        continue;
 460
 461                if (!found && ack_req) {
 462                        found = true;
 463                        memcpy(lw->lease_key, open->lease_key,
 464                               SMB2_LEASE_KEY_SIZE);
 465                        lw->tlink = cifs_get_tlink(open->tlink);
 466                        queue_work(cifsiod_wq, &lw->lease_break);
 467                }
 468
 469                cifs_dbg(FYI, "found in the pending open list\n");
 470                cifs_dbg(FYI, "lease key match, lease break 0x%d\n",
 471                         le32_to_cpu(rsp->NewLeaseState));
 472
 473                open->oplock = lease_state;
 474        }
 475        return found;
 476}
 477
 478static bool
 479smb2_is_valid_lease_break(char *buffer)
 480{
 481        struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
 482        struct list_head *tmp, *tmp1, *tmp2;
 483        struct TCP_Server_Info *server;
 484        struct cifs_ses *ses;
 485        struct cifs_tcon *tcon;
 486        struct smb2_lease_break_work *lw;
 487
 488        lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
 489        if (!lw)
 490                return false;
 491
 492        INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
 493        lw->lease_state = rsp->NewLeaseState;
 494
 495        cifs_dbg(FYI, "Checking for lease break\n");
 496
 497        /* look up tcon based on tid & uid */
 498        spin_lock(&cifs_tcp_ses_lock);
 499        list_for_each(tmp, &cifs_tcp_ses_list) {
 500                server = list_entry(tmp, struct TCP_Server_Info, tcp_ses_list);
 501
 502                list_for_each(tmp1, &server->smb_ses_list) {
 503                        ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);
 504
 505                        spin_lock(&cifs_file_list_lock);
 506                        list_for_each(tmp2, &ses->tcon_list) {
 507                                tcon = list_entry(tmp2, struct cifs_tcon,
 508                                                  tcon_list);
 509                                cifs_stats_inc(
 510                                    &tcon->stats.cifs_stats.num_oplock_brks);
 511                                if (smb2_tcon_has_lease(tcon, rsp, lw)) {
 512                                        spin_unlock(&cifs_file_list_lock);
 513                                        spin_unlock(&cifs_tcp_ses_lock);
 514                                        return true;
 515                                }
 516                        }
 517                        spin_unlock(&cifs_file_list_lock);
 518                }
 519        }
 520        spin_unlock(&cifs_tcp_ses_lock);
 521        kfree(lw);
 522        cifs_dbg(FYI, "Can not process lease break - no lease matched\n");
 523        return false;
 524}
 525
 526bool
 527smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 528{
 529        struct smb2_oplock_break *rsp = (struct smb2_oplock_break *)buffer;
 530        struct list_head *tmp, *tmp1, *tmp2;
 531        struct cifs_ses *ses;
 532        struct cifs_tcon *tcon;
 533        struct cifsInodeInfo *cinode;
 534        struct cifsFileInfo *cfile;
 535
 536        cifs_dbg(FYI, "Checking for oplock break\n");
 537
 538        if (rsp->hdr.Command != SMB2_OPLOCK_BREAK)
 539                return false;
 540
 541        if (rsp->StructureSize !=
 542                                smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
 543                if (le16_to_cpu(rsp->StructureSize) == 44)
 544                        return smb2_is_valid_lease_break(buffer);
 545                else
 546                        return false;
 547        }
 548
 549        cifs_dbg(FYI, "oplock level 0x%d\n", rsp->OplockLevel);
 550
 551        /* look up tcon based on tid & uid */
 552        spin_lock(&cifs_tcp_ses_lock);
 553        list_for_each(tmp, &server->smb_ses_list) {
 554                ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 555                list_for_each(tmp1, &ses->tcon_list) {
 556                        tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 557
 558                        cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 559                        spin_lock(&cifs_file_list_lock);
 560                        list_for_each(tmp2, &tcon->openFileList) {
 561                                cfile = list_entry(tmp2, struct cifsFileInfo,
 562                                                     tlist);
 563                                if (rsp->PersistentFid !=
 564                                    cfile->fid.persistent_fid ||
 565                                    rsp->VolatileFid !=
 566                                    cfile->fid.volatile_fid)
 567                                        continue;
 568
 569                                cifs_dbg(FYI, "file id match, oplock break\n");
 570                                cinode = CIFS_I(cfile->dentry->d_inode);
 571
 572                                if (!CIFS_CACHE_WRITE(cinode) &&
 573                                    rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
 574                                        cfile->oplock_break_cancelled = true;
 575                                else
 576                                        cfile->oplock_break_cancelled = false;
 577
 578                                server->ops->set_oplock_level(cinode,
 579                                  rsp->OplockLevel ? SMB2_OPLOCK_LEVEL_II : 0,
 580                                  0, NULL);
 581
 582                                queue_work(cifsiod_wq, &cfile->oplock_break);
 583
 584                                spin_unlock(&cifs_file_list_lock);
 585                                spin_unlock(&cifs_tcp_ses_lock);
 586                                return true;
 587                        }
 588                        spin_unlock(&cifs_file_list_lock);
 589                        spin_unlock(&cifs_tcp_ses_lock);
 590                        cifs_dbg(FYI, "No matching file for oplock break\n");
 591                        return true;
 592                }
 593        }
 594        spin_unlock(&cifs_tcp_ses_lock);
 595        cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 596        return false;
 597}
 598