kernel/fs/cifs/misc.c

   1 /*
   2  *   fs/cifs/misc.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/slab.h>
  23 #include <linux/ctype.h>
  24 #include <linux/mempool.h>
  25 #include "cifspdu.h"
  26 #include "cifsglob.h"
  27 #include "cifsproto.h"
  28 #include "cifs_debug.h"
  29 #include "smberr.h"
  30 #include "nterr.h"
  31 #include "cifs_unicode.h"
  32 #ifdef CONFIG_CIFS_SMB2
  33 #include "smb2pdu.h"
  34 #endif
  35
  36 extern mempool_t *cifs_sm_req_poolp;
  37 extern mempool_t *cifs_req_poolp;
  38
  39 /* The xid serves as a useful identifier for each incoming vfs request,
  40    in a similar way to the mid which is useful to track each sent smb,
  41    and CurrentXid can also provide a running counter (although it
  42    will eventually wrap past zero) of the total vfs operations handled
  43    since the cifs fs was mounted */
  44
  45 unsigned int
  46 _get_xid(void)
  47 {
  48         unsigned int xid;
  49
  50         spin_lock(&GlobalMid_Lock);
  51         GlobalTotalActiveXid++;
  52
  53         /* keep high water mark for number of simultaneous ops in filesystem */
  54         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  55                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  56         if (GlobalTotalActiveXid > 65000)
  57                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  58         xid = GlobalCurrentXid++;
  59         spin_unlock(&GlobalMid_Lock);
  60         return xid;
  61 }
  62
  63 void
  64 _free_xid(unsigned int xid)
  65 {
  66         spin_lock(&GlobalMid_Lock);
  67         /* if (GlobalTotalActiveXid == 0)
  68                 BUG(); */
  69         GlobalTotalActiveXid--;
  70         spin_unlock(&GlobalMid_Lock);
  71 }
  72
  73 struct cifs_ses *
  74 sesInfoAlloc(void)
  75 {
  76         struct cifs_ses *ret_buf;
  77
  78         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  79         if (ret_buf) {
  80                 atomic_inc(&sesInfoAllocCount);
  81                 ret_buf->status = CifsNew;
  82                 ++ret_buf->ses_count;
  83                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  84                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  85                 mutex_init(&ret_buf->session_mutex);
  86         }
  87         return ret_buf;
  88 }
  89
  90 void
  91 sesInfoFree(struct cifs_ses *buf_to_free)
  92 {
  93         if (buf_to_free == NULL) {
  94                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  95                 return;
  96         }
  97
  98         atomic_dec(&sesInfoAllocCount);
  99         kfree(buf_to_free->serverOS);
 100         kfree(buf_to_free->serverDomain);
 101         kfree(buf_to_free->serverNOS);
 102         if (buf_to_free->password) {
 103                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 104                 kfree(buf_to_free->password);
 105         }
 106         kfree(buf_to_free->user_name);
 107         kfree(buf_to_free->domainName);
 108         kfree(buf_to_free->auth_key.response);
 109         kfree(buf_to_free);
 110 }
 111
 112 struct cifs_tcon *
 113 tconInfoAlloc(void)
 114 {
 115         struct cifs_tcon *ret_buf;
 116         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
 117         if (ret_buf) {
 118                 atomic_inc(&tconInfoAllocCount);
 119                 ret_buf->tidStatus = CifsNew;
 120                 ++ret_buf->tc_count;
 121                 INIT_LIST_HEAD(&ret_buf->openFileList);
 122                 INIT_LIST_HEAD(&ret_buf->tcon_list);
 123                 spin_lock_init(&ret_buf->open_file_lock);
 124 #ifdef CONFIG_CIFS_STATS
 125                 spin_lock_init(&ret_buf->stat_lock);
 126 #endif
 127         }
 128         return ret_buf;
 129 }
 130
 131 void
 132 tconInfoFree(struct cifs_tcon *buf_to_free)
 133 {
 134         if (buf_to_free == NULL) {
 135                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 136                 return;
 137         }
 138         atomic_dec(&tconInfoAllocCount);
 139         kfree(buf_to_free->nativeFileSystem);
 140         if (buf_to_free->password) {
 141                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 142                 kfree(buf_to_free->password);
 143         }
 144         kfree(buf_to_free);
 145 }
 146
 147 struct smb_hdr *
 148 cifs_buf_get(void)
 149 {
 150         struct smb_hdr *ret_buf = NULL;
 151         size_t buf_size = sizeof(struct smb_hdr);
 152
 153 #ifdef CONFIG_CIFS_SMB2
 154         /*
 155          * SMB2 header is bigger than CIFS one - no problems to clean some
 156          * more bytes for CIFS.
 157          */
 158         buf_size = sizeof(struct smb2_hdr);
 159 #endif
 160         /*
 161          * We could use negotiated size instead of max_msgsize -
 162          * but it may be more efficient to always alloc same size
 163          * albeit slightly larger than necessary and maxbuffersize
 164          * defaults to this and can not be bigger.
 165          */
 166         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 167
 168         /* clear the first few header bytes */
 169         /* for most paths, more is cleared in header_assemble */
 170         if (ret_buf) {
 171                 memset(ret_buf, 0, buf_size + 3);
 172                 atomic_inc(&bufAllocCount);
 173 #ifdef CONFIG_CIFS_STATS2
 174                 atomic_inc(&totBufAllocCount);
 175 #endif /* CONFIG_CIFS_STATS2 */
 176         }
 177
 178         return ret_buf;
 179 }
 180
 181 void
 182 cifs_buf_release(void *buf_to_free)
 183 {
 184         if (buf_to_free == NULL) {
 185                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 186                 return;
 187         }
 188         mempool_free(buf_to_free, cifs_req_poolp);
 189
 190         atomic_dec(&bufAllocCount);
 191         return;
 192 }
 193
 194 struct smb_hdr *
 195 cifs_small_buf_get(void)
 196 {
 197         struct smb_hdr *ret_buf = NULL;
 198
 199 /* We could use negotiated size instead of max_msgsize -
 200    but it may be more efficient to always alloc same size
 201    albeit slightly larger than necessary and maxbuffersize
 202    defaults to this and can not be bigger */
 203         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 204         if (ret_buf) {
 205         /* No need to clear memory here, cleared in header assemble */
 206         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 207                 atomic_inc(&smBufAllocCount);
 208 #ifdef CONFIG_CIFS_STATS2
 209                 atomic_inc(&totSmBufAllocCount);
 210 #endif /* CONFIG_CIFS_STATS2 */
 211
 212         }
 213         return ret_buf;
 214 }
 215
 216 void
 217 cifs_small_buf_release(void *buf_to_free)
 218 {
 219
 220         if (buf_to_free == NULL) {
 221                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 222                 return;
 223         }
 224         mempool_free(buf_to_free, cifs_sm_req_poolp);
 225
 226         atomic_dec(&smBufAllocCount);
 227         return;
 228 }
 229
 230 void
 231 free_rsp_buf(int resp_buftype, void *rsp)
 232 {
 233         if (resp_buftype == CIFS_SMALL_BUFFER)
 234                 cifs_small_buf_release(rsp);
 235         else if (resp_buftype == CIFS_LARGE_BUFFER)
 236                 cifs_buf_release(rsp);
 237 }
 238
 239 /* NB: MID can not be set if treeCon not passed in, in that
 240    case it is responsbility of caller to set the mid */
 241 void
 242 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 243                 const struct cifs_tcon *treeCon, int word_count
 244                 /* length of fixed section (word count) in two byte units  */)
 245 {
 246         char *temp = (char *) buffer;
 247
 248         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 249
 250         buffer->smb_buf_length = cpu_to_be32(
 251             (2 * word_count) + sizeof(struct smb_hdr) -
 252             4 /*  RFC 1001 length field does not count */  +
 253             2 /* for bcc field itself */) ;
 254
 255         buffer->Protocol[0] = 0xFF;
 256         buffer->Protocol[1] = 'S';
 257         buffer->Protocol[2] = 'M';
 258         buffer->Protocol[3] = 'B';
 259         buffer->Command = smb_command;
 260         buffer->Flags = 0x00;   /* case sensitive */
 261         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 262         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 263         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 264         if (treeCon) {
 265                 buffer->Tid = treeCon->tid;
 266                 if (treeCon->ses) {
 267                         if (treeCon->ses->capabilities & CAP_UNICODE)
 268                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 269                         if (treeCon->ses->capabilities & CAP_STATUS32)
 270                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 271
 272                         /* Uid is not converted */
 273                         buffer->Uid = treeCon->ses->Suid;
 274                         buffer->Mid = get_next_mid(treeCon->ses->server);
 275                 }
 276                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 277                         buffer->Flags2 |= SMBFLG2_DFS;
 278                 if (treeCon->nocase)
 279                         buffer->Flags  |= SMBFLG_CASELESS;
 280                 if ((treeCon->ses) && (treeCon->ses->server))
 281                         if (treeCon->ses->server->sign)
 282                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 283         }
 284
 285 /*  endian conversion of flags is now done just before sending */
 286         buffer->WordCount = (char) word_count;
 287         return;
 288 }
 289
 290 static int
 291 check_smb_hdr(struct smb_hdr *smb)
 292 {
 293         /* does it have the right SMB "signature" ? */
 294         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 295                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 296                          *(unsigned int *)smb->Protocol);
 297                 return 1;
 298         }
 299
 300         /* if it's a response then accept */
 301         if (smb->Flags & SMBFLG_RESPONSE)
 302                 return 0;
 303
 304         /* only one valid case where server sends us request */
 305         if (smb->Command == SMB_COM_LOCKING_ANDX)
 306                 return 0;
 307
 308         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 309                  get_mid(smb));
 310         return 1;
 311 }
 312
 313 int
 314 checkSMB(char *buf, unsigned int total_read)
 315 {
 316         struct smb_hdr *smb = (struct smb_hdr *)buf;
 317         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 318         __u32 clc_len;  /* calculated length */
 319         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 320                  total_read, rfclen);
 321
 322         /* is this frame too small to even get to a BCC? */
 323         if (total_read < 2 + sizeof(struct smb_hdr)) {
 324                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 325                             && (smb->Status.CifsError != 0)) {
 326                         /* it's an error return */
 327                         smb->WordCount = 0;
 328                         /* some error cases do not return wct and bcc */
 329                         return 0;
 330                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 331                                 (smb->WordCount == 0)) {
 332                         char *tmp = (char *)smb;
 333                         /* Need to work around a bug in two servers here */
 334                         /* First, check if the part of bcc they sent was zero */
 335                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 336                                 /* some servers return only half of bcc
 337                                  * on simple responses (wct, bcc both zero)
 338                                  * in particular have seen this on
 339                                  * ulogoffX and FindClose. This leaves
 340                                  * one byte of bcc potentially unitialized
 341                                  */
 342                                 /* zero rest of bcc */
 343                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 344                                 return 0;
 345                         }
 346                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 347                 } else {
 348                         cifs_dbg(VFS, "Length less than smb header size\n");
 349                 }
 350                 return -EIO;
 351         }
 352
 353         /* otherwise, there is enough to get to the BCC */
 354         if (check_smb_hdr(smb))
 355                 return -EIO;
 356         clc_len = smbCalcSize(smb);
 357
 358         if (4 + rfclen != total_read) {
 359                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 360                          rfclen);
 361                 return -EIO;
 362         }
 363
 364         if (4 + rfclen != clc_len) {
 365                 __u16 mid = get_mid(smb);
 366                 /* check if bcc wrapped around for large read responses */
 367                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 368                         /* check if lengths match mod 64K */
 369                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 370                                 return 0; /* bcc wrapped */
 371                 }
 372                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 373                          clc_len, 4 + rfclen, mid);
 374
 375                 if (4 + rfclen < clc_len) {
 376                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 377                                  rfclen, mid);
 378                         return -EIO;
 379                 } else if (rfclen > clc_len + 512) {
 380                         /*
 381                          * Some servers (Windows XP in particular) send more
 382                          * data than the lengths in the SMB packet would
 383                          * indicate on certain calls (byte range locks and
 384                          * trans2 find first calls in particular). While the
 385                          * client can handle such a frame by ignoring the
 386                          * trailing data, we choose limit the amount of extra
 387                          * data to 512 bytes.
 388                          */
 389                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 390                                  rfclen, mid);
 391                         return -EIO;
 392                 }
 393         }
 394         return 0;
 395 }
 396
 397 bool
 398 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 399 {
 400         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 401         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 402         struct list_head *tmp, *tmp1, *tmp2;
 403         struct cifs_ses *ses;
 404         struct cifs_tcon *tcon;
 405         struct cifsInodeInfo *pCifsInode;
 406         struct cifsFileInfo *netfile;
 407
 408         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 409         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 410            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 411                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 412                         (struct smb_com_transaction_change_notify_rsp *)buf;
 413                 struct file_notify_information *pnotify;
 414                 __u32 data_offset = 0;
 415                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 416                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 417
 418                         pnotify = (struct file_notify_information *)
 419                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 420                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 421                                  pnotify->FileName, pnotify->Action);
 422                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 423                                 sizeof(struct smb_hdr)+60); */
 424                         return true;
 425                 }
 426                 if (pSMBr->hdr.Status.CifsError) {
 427                         cifs_dbg(FYI, "notify err 0x%x\n",
 428                                  pSMBr->hdr.Status.CifsError);
 429                         return true;
 430                 }
 431                 return false;
 432         }
 433         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 434                 return false;
 435         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 436                 /* no sense logging error on invalid handle on oplock
 437                    break - harmless race between close request and oplock
 438                    break response is expected from time to time writing out
 439                    large dirty files cached on the client */
 440                 if ((NT_STATUS_INVALID_HANDLE) ==
 441                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 442                         cifs_dbg(FYI, "invalid handle on oplock break\n");
 443                         return true;
 444                 } else if (ERRbadfid ==
 445                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 446                         return true;
 447                 } else {
 448                         return false; /* on valid oplock brk we get "request" */
 449                 }
 450         }
 451         if (pSMB->hdr.WordCount != 8)
 452                 return false;
 453
 454         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 455                  pSMB->LockType, pSMB->OplockLevel);
 456         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 457                 return false;
 458
 459         /* look up tcon based on tid & uid */
 460         spin_lock(&cifs_tcp_ses_lock);
 461         list_for_each(tmp, &srv->smb_ses_list) {
 462                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 463                 list_for_each(tmp1, &ses->tcon_list) {
 464                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 465                         if (tcon->tid != buf->Tid)
 466                                 continue;
 467
 468                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 469                         spin_lock(&tcon->open_file_lock);
 470                         list_for_each(tmp2, &tcon->openFileList) {
 471                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 472                                                      tlist);
 473                                 if (pSMB->Fid != netfile->fid.netfid)
 474                                         continue;
 475
 476                                 cifs_dbg(FYI, "file id match, oplock break\n");
 477                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 478
 479                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 480                                         &pCifsInode->flags);
 481
 482                                 /*
 483                                  * Set flag if the server downgrades the oplock
 484                                  * to L2 else clear.
 485                                  */
 486                                 if (pSMB->OplockLevel)
 487                                         set_bit(
 488                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 489                                            &pCifsInode->flags);
 490                                 else
 491                                         clear_bit(
 492                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 493                                            &pCifsInode->flags);
 494
 495                                 queue_work(cifsiod_wq,
 496                                            &netfile->oplock_break);
 497                                 netfile->oplock_break_cancelled = false;
 498
 499                                 spin_unlock(&tcon->open_file_lock);
 500                                 spin_unlock(&cifs_tcp_ses_lock);
 501                                 return true;
 502                         }
 503                         spin_unlock(&tcon->open_file_lock);
 504                         spin_unlock(&cifs_tcp_ses_lock);
 505                         cifs_dbg(FYI, "No matching file for oplock break\n");
 506                         return true;
 507                 }
 508         }
 509         spin_unlock(&cifs_tcp_ses_lock);
 510         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 511         return true;
 512 }
 513
 514 void
 515 dump_smb(void *buf, int smb_buf_length)
 516 {
 517         if (traceSMB == 0)
 518                 return;
 519
 520         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 521                        smb_buf_length, true);
 522 }
 523
 524 void
 525 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 526 {
 527         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 528                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 529                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s. This server doesn't seem to support them properly. Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n",
 530                          cifs_sb_master_tcon(cifs_sb)->treeName);
 531         }
 532 }
 533
 534 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 535 {
 536         oplock &= 0xF;
 537
 538         if (oplock == OPLOCK_EXCLUSIVE) {
 539                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 540                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 541                          &cinode->vfs_inode);
 542         } else if (oplock == OPLOCK_READ) {
 543                 cinode->oplock = CIFS_CACHE_READ_FLG;
 544                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 545                          &cinode->vfs_inode);
 546         } else
 547                 cinode->oplock = 0;
 548 }
 549
 550 /*
 551  * We wait for oplock breaks to be processed before we attempt to perform
 552  * writes.
 553  */
 554 int cifs_get_writer(struct cifsInodeInfo *cinode)
 555 {
 556         int rc;
 557
 558 start:
 559         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 560                          TASK_KILLABLE);
 561         if (rc)
 562                 return rc;
 563
 564         spin_lock(&cinode->writers_lock);
 565         if (!cinode->writers)
 566                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 567         cinode->writers++;
 568         /* Check to see if we have started servicing an oplock break */
 569         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 570                 cinode->writers--;
 571                 if (cinode->writers == 0) {
 572                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 573                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 574                 }
 575                 spin_unlock(&cinode->writers_lock);
 576                 goto start;
 577         }
 578         spin_unlock(&cinode->writers_lock);
 579         return 0;
 580 }
 581
 582 void cifs_put_writer(struct cifsInodeInfo *cinode)
 583 {
 584         spin_lock(&cinode->writers_lock);
 585         cinode->writers--;
 586         if (cinode->writers == 0) {
 587                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 588                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 589         }
 590         spin_unlock(&cinode->writers_lock);
 591 }
 592
 593 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 594 {
 595         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 596         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 597 }
 598
 599 bool
 600 backup_cred(struct cifs_sb_info *cifs_sb)
 601 {
 602         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 603                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 604                         return true;
 605         }
 606         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 607                 if (in_group_p(cifs_sb->mnt_backupgid))
 608                         return true;
 609         }
 610
 611         return false;
 612 }
 613
 614 void
 615 cifs_del_pending_open(struct cifs_pending_open *open)
 616 {
 617         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 618         list_del(&open->olist);
 619         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 620 }
 621
 622 void
 623 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 624                              struct cifs_pending_open *open)
 625 {
 626 #ifdef CONFIG_CIFS_SMB2
 627         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 628 #endif
 629         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 630         open->tlink = tlink;
 631         fid->pending_open = open;
 632         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 633 }
 634
 635 void
 636 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 637                       struct cifs_pending_open *open)
 638 {
 639         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 640         cifs_add_pending_open_locked(fid, tlink, open);
 641         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 642 }