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         kzfree(buf_to_free->password);
 103         kfree(buf_to_free->user_name);
 104         kfree(buf_to_free->domainName);
 105         kzfree(buf_to_free->auth_key.response);
 106         kzfree(buf_to_free);
 107 }
 108
 109 struct cifs_tcon *
 110 tconInfoAlloc(void)
 111 {
 112         struct cifs_tcon *ret_buf;
 113         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
 114         if (ret_buf) {
 115                 atomic_inc(&tconInfoAllocCount);
 116                 ret_buf->tidStatus = CifsNew;
 117                 ++ret_buf->tc_count;
 118                 INIT_LIST_HEAD(&ret_buf->openFileList);
 119                 INIT_LIST_HEAD(&ret_buf->tcon_list);
 120                 spin_lock_init(&ret_buf->open_file_lock);
 121 #ifdef CONFIG_CIFS_STATS
 122                 spin_lock_init(&ret_buf->stat_lock);
 123 #endif
 124         }
 125         return ret_buf;
 126 }
 127
 128 void
 129 tconInfoFree(struct cifs_tcon *buf_to_free)
 130 {
 131         if (buf_to_free == NULL) {
 132                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 133                 return;
 134         }
 135         atomic_dec(&tconInfoAllocCount);
 136         kfree(buf_to_free->nativeFileSystem);
 137         kzfree(buf_to_free->password);
 138         kfree(buf_to_free);
 139 }
 140
 141 struct smb_hdr *
 142 cifs_buf_get(void)
 143 {
 144         struct smb_hdr *ret_buf = NULL;
 145         size_t buf_size = sizeof(struct smb_hdr);
 146
 147 #ifdef CONFIG_CIFS_SMB2
 148         /*
 149          * SMB2 header is bigger than CIFS one - no problems to clean some
 150          * more bytes for CIFS.
 151          */
 152         buf_size = sizeof(struct smb2_hdr);
 153 #endif
 154         /*
 155          * We could use negotiated size instead of max_msgsize -
 156          * but it may be more efficient to always alloc same size
 157          * albeit slightly larger than necessary and maxbuffersize
 158          * defaults to this and can not be bigger.
 159          */
 160         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 161
 162         /* clear the first few header bytes */
 163         /* for most paths, more is cleared in header_assemble */
 164         if (ret_buf) {
 165                 memset(ret_buf, 0, buf_size + 3);
 166                 atomic_inc(&bufAllocCount);
 167 #ifdef CONFIG_CIFS_STATS2
 168                 atomic_inc(&totBufAllocCount);
 169 #endif /* CONFIG_CIFS_STATS2 */
 170         }
 171
 172         return ret_buf;
 173 }
 174
 175 void
 176 cifs_buf_release(void *buf_to_free)
 177 {
 178         if (buf_to_free == NULL) {
 179                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 180                 return;
 181         }
 182         mempool_free(buf_to_free, cifs_req_poolp);
 183
 184         atomic_dec(&bufAllocCount);
 185         return;
 186 }
 187
 188 struct smb_hdr *
 189 cifs_small_buf_get(void)
 190 {
 191         struct smb_hdr *ret_buf = NULL;
 192
 193 /* We could use negotiated size instead of max_msgsize -
 194    but it may be more efficient to always alloc same size
 195    albeit slightly larger than necessary and maxbuffersize
 196    defaults to this and can not be bigger */
 197         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 198         if (ret_buf) {
 199         /* No need to clear memory here, cleared in header assemble */
 200         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 201                 atomic_inc(&smBufAllocCount);
 202 #ifdef CONFIG_CIFS_STATS2
 203                 atomic_inc(&totSmBufAllocCount);
 204 #endif /* CONFIG_CIFS_STATS2 */
 205
 206         }
 207         return ret_buf;
 208 }
 209
 210 void
 211 cifs_small_buf_release(void *buf_to_free)
 212 {
 213
 214         if (buf_to_free == NULL) {
 215                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 216                 return;
 217         }
 218         mempool_free(buf_to_free, cifs_sm_req_poolp);
 219
 220         atomic_dec(&smBufAllocCount);
 221         return;
 222 }
 223
 224 void
 225 free_rsp_buf(int resp_buftype, void *rsp)
 226 {
 227         if (resp_buftype == CIFS_SMALL_BUFFER)
 228                 cifs_small_buf_release(rsp);
 229         else if (resp_buftype == CIFS_LARGE_BUFFER)
 230                 cifs_buf_release(rsp);
 231 }
 232
 233 /* NB: MID can not be set if treeCon not passed in, in that
 234    case it is responsbility of caller to set the mid */
 235 void
 236 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 237                 const struct cifs_tcon *treeCon, int word_count
 238                 /* length of fixed section (word count) in two byte units  */)
 239 {
 240         char *temp = (char *) buffer;
 241
 242         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 243
 244         buffer->smb_buf_length = cpu_to_be32(
 245             (2 * word_count) + sizeof(struct smb_hdr) -
 246             4 /*  RFC 1001 length field does not count */  +
 247             2 /* for bcc field itself */) ;
 248
 249         buffer->Protocol[0] = 0xFF;
 250         buffer->Protocol[1] = 'S';
 251         buffer->Protocol[2] = 'M';
 252         buffer->Protocol[3] = 'B';
 253         buffer->Command = smb_command;
 254         buffer->Flags = 0x00;   /* case sensitive */
 255         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 256         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 257         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 258         if (treeCon) {
 259                 buffer->Tid = treeCon->tid;
 260                 if (treeCon->ses) {
 261                         if (treeCon->ses->capabilities & CAP_UNICODE)
 262                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 263                         if (treeCon->ses->capabilities & CAP_STATUS32)
 264                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 265
 266                         /* Uid is not converted */
 267                         buffer->Uid = treeCon->ses->Suid;
 268                         buffer->Mid = get_next_mid(treeCon->ses->server);
 269                 }
 270                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 271                         buffer->Flags2 |= SMBFLG2_DFS;
 272                 if (treeCon->nocase)
 273                         buffer->Flags  |= SMBFLG_CASELESS;
 274                 if ((treeCon->ses) && (treeCon->ses->server))
 275                         if (treeCon->ses->server->sign)
 276                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 277         }
 278
 279 /*  endian conversion of flags is now done just before sending */
 280         buffer->WordCount = (char) word_count;
 281         return;
 282 }
 283
 284 static int
 285 check_smb_hdr(struct smb_hdr *smb)
 286 {
 287         /* does it have the right SMB "signature" ? */
 288         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 289                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 290                          *(unsigned int *)smb->Protocol);
 291                 return 1;
 292         }
 293
 294         /* if it's a response then accept */
 295         if (smb->Flags & SMBFLG_RESPONSE)
 296                 return 0;
 297
 298         /* only one valid case where server sends us request */
 299         if (smb->Command == SMB_COM_LOCKING_ANDX)
 300                 return 0;
 301
 302         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 303                  get_mid(smb));
 304         return 1;
 305 }
 306
 307 int
 308 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 309 {
 310         struct smb_hdr *smb = (struct smb_hdr *)buf;
 311         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 312         __u32 clc_len;  /* calculated length */
 313         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 314                  total_read, rfclen);
 315
 316         /* is this frame too small to even get to a BCC? */
 317         if (total_read < 2 + sizeof(struct smb_hdr)) {
 318                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 319                             && (smb->Status.CifsError != 0)) {
 320                         /* it's an error return */
 321                         smb->WordCount = 0;
 322                         /* some error cases do not return wct and bcc */
 323                         return 0;
 324                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 325                                 (smb->WordCount == 0)) {
 326                         char *tmp = (char *)smb;
 327                         /* Need to work around a bug in two servers here */
 328                         /* First, check if the part of bcc they sent was zero */
 329                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 330                                 /* some servers return only half of bcc
 331                                  * on simple responses (wct, bcc both zero)
 332                                  * in particular have seen this on
 333                                  * ulogoffX and FindClose. This leaves
 334                                  * one byte of bcc potentially unitialized
 335                                  */
 336                                 /* zero rest of bcc */
 337                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 338                                 return 0;
 339                         }
 340                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 341                 } else {
 342                         cifs_dbg(VFS, "Length less than smb header size\n");
 343                 }
 344                 return -EIO;
 345         }
 346
 347         /* otherwise, there is enough to get to the BCC */
 348         if (check_smb_hdr(smb))
 349                 return -EIO;
 350         clc_len = smbCalcSize(smb);
 351
 352         if (4 + rfclen != total_read) {
 353                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 354                          rfclen);
 355                 return -EIO;
 356         }
 357
 358         if (4 + rfclen != clc_len) {
 359                 __u16 mid = get_mid(smb);
 360                 /* check if bcc wrapped around for large read responses */
 361                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 362                         /* check if lengths match mod 64K */
 363                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 364                                 return 0; /* bcc wrapped */
 365                 }
 366                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 367                          clc_len, 4 + rfclen, mid);
 368
 369                 if (4 + rfclen < clc_len) {
 370                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 371                                  rfclen, mid);
 372                         return -EIO;
 373                 } else if (rfclen > clc_len + 512) {
 374                         /*
 375                          * Some servers (Windows XP in particular) send more
 376                          * data than the lengths in the SMB packet would
 377                          * indicate on certain calls (byte range locks and
 378                          * trans2 find first calls in particular). While the
 379                          * client can handle such a frame by ignoring the
 380                          * trailing data, we choose limit the amount of extra
 381                          * data to 512 bytes.
 382                          */
 383                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 384                                  rfclen, mid);
 385                         return -EIO;
 386                 }
 387         }
 388         return 0;
 389 }
 390
 391 bool
 392 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 393 {
 394         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 395         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 396         struct list_head *tmp, *tmp1, *tmp2;
 397         struct cifs_ses *ses;
 398         struct cifs_tcon *tcon;
 399         struct cifsInodeInfo *pCifsInode;
 400         struct cifsFileInfo *netfile;
 401
 402         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 403         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 404            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 405                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 406                         (struct smb_com_transaction_change_notify_rsp *)buf;
 407                 struct file_notify_information *pnotify;
 408                 __u32 data_offset = 0;
 409                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 410
 411                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 412                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 413
 414                         if (data_offset >
 415                             len - sizeof(struct file_notify_information)) {
 416                                 cifs_dbg(FYI, "invalid data_offset %u\n",
 417                                          data_offset);
 418                                 return true;
 419                         }
 420                         pnotify = (struct file_notify_information *)
 421                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 422                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 423                                  pnotify->FileName, pnotify->Action);
 424                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 425                                 sizeof(struct smb_hdr)+60); */
 426                         return true;
 427                 }
 428                 if (pSMBr->hdr.Status.CifsError) {
 429                         cifs_dbg(FYI, "notify err 0x%x\n",
 430                                  pSMBr->hdr.Status.CifsError);
 431                         return true;
 432                 }
 433                 return false;
 434         }
 435         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 436                 return false;
 437         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 438                 /* no sense logging error on invalid handle on oplock
 439                    break - harmless race between close request and oplock
 440                    break response is expected from time to time writing out
 441                    large dirty files cached on the client */
 442                 if ((NT_STATUS_INVALID_HANDLE) ==
 443                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 444                         cifs_dbg(FYI, "invalid handle on oplock break\n");
 445                         return true;
 446                 } else if (ERRbadfid ==
 447                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 448                         return true;
 449                 } else {
 450                         return false; /* on valid oplock brk we get "request" */
 451                 }
 452         }
 453         if (pSMB->hdr.WordCount != 8)
 454                 return false;
 455
 456         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 457                  pSMB->LockType, pSMB->OplockLevel);
 458         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 459                 return false;
 460
 461         /* look up tcon based on tid & uid */
 462         spin_lock(&cifs_tcp_ses_lock);
 463         list_for_each(tmp, &srv->smb_ses_list) {
 464                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 465                 list_for_each(tmp1, &ses->tcon_list) {
 466                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 467                         if (tcon->tid != buf->Tid)
 468                                 continue;
 469
 470                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 471                         spin_lock(&tcon->open_file_lock);
 472                         list_for_each(tmp2, &tcon->openFileList) {
 473                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 474                                                      tlist);
 475                                 if (pSMB->Fid != netfile->fid.netfid)
 476                                         continue;
 477
 478                                 cifs_dbg(FYI, "file id match, oplock break\n");
 479                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 480
 481                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 482                                         &pCifsInode->flags);
 483
 484                                 netfile->oplock_epoch = 0;
 485                                 netfile->oplock_level = pSMB->OplockLevel;
 486                                 netfile->oplock_break_cancelled = false;
 487                                 cifs_queue_oplock_break(netfile);
 488
 489                                 spin_unlock(&tcon->open_file_lock);
 490                                 spin_unlock(&cifs_tcp_ses_lock);
 491                                 return true;
 492                         }
 493                         spin_unlock(&tcon->open_file_lock);
 494                         spin_unlock(&cifs_tcp_ses_lock);
 495                         cifs_dbg(FYI, "No matching file for oplock break\n");
 496                         return true;
 497                 }
 498         }
 499         spin_unlock(&cifs_tcp_ses_lock);
 500         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 501         return true;
 502 }
 503
 504 void
 505 dump_smb(void *buf, int smb_buf_length)
 506 {
 507         if (traceSMB == 0)
 508                 return;
 509
 510         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 511                        smb_buf_length, true);
 512 }
 513
 514 void
 515 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 516 {
 517         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 518                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 519                 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",
 520                          cifs_sb_master_tcon(cifs_sb)->treeName);
 521         }
 522 }
 523
 524 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 525 {
 526         oplock &= 0xF;
 527
 528         if (oplock == OPLOCK_EXCLUSIVE) {
 529                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 530                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 531                          &cinode->vfs_inode);
 532         } else if (oplock == OPLOCK_READ) {
 533                 cinode->oplock = CIFS_CACHE_READ_FLG;
 534                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 535                          &cinode->vfs_inode);
 536         } else
 537                 cinode->oplock = 0;
 538 }
 539
 540 /*
 541  * We wait for oplock breaks to be processed before we attempt to perform
 542  * writes.
 543  */
 544 int cifs_get_writer(struct cifsInodeInfo *cinode)
 545 {
 546         int rc;
 547
 548 start:
 549         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 550                          TASK_KILLABLE);
 551         if (rc)
 552                 return rc;
 553
 554         spin_lock(&cinode->writers_lock);
 555         if (!cinode->writers)
 556                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 557         cinode->writers++;
 558         /* Check to see if we have started servicing an oplock break */
 559         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 560                 cinode->writers--;
 561                 if (cinode->writers == 0) {
 562                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 563                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 564                 }
 565                 spin_unlock(&cinode->writers_lock);
 566                 goto start;
 567         }
 568         spin_unlock(&cinode->writers_lock);
 569         return 0;
 570 }
 571
 572 void cifs_put_writer(struct cifsInodeInfo *cinode)
 573 {
 574         spin_lock(&cinode->writers_lock);
 575         cinode->writers--;
 576         if (cinode->writers == 0) {
 577                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 578                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 579         }
 580         spin_unlock(&cinode->writers_lock);
 581 }
 582
 583 /**
 584  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 585  *
 586  * This function is called from the demultiplex thread when it
 587  * receives an oplock break for @cfile.
 588  *
 589  * Assumes the tcon->open_file_lock is held.
 590  * Assumes cfile->file_info_lock is NOT held.
 591  */
 592 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 593 {
 594         /*
 595          * Bump the handle refcount now while we hold the
 596          * open_file_lock to enforce the validity of it for the oplock
 597          * break handler. The matching put is done at the end of the
 598          * handler.
 599          */
 600         cifsFileInfo_get(cfile);
 601
 602         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 603 }
 604
 605 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 606 {
 607         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 608         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 609 }
 610
 611 bool
 612 backup_cred(struct cifs_sb_info *cifs_sb)
 613 {
 614         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 615                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 616                         return true;
 617         }
 618         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 619                 if (in_group_p(cifs_sb->mnt_backupgid))
 620                         return true;
 621         }
 622
 623         return false;
 624 }
 625
 626 void
 627 cifs_del_pending_open(struct cifs_pending_open *open)
 628 {
 629         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 630         list_del(&open->olist);
 631         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 632 }
 633
 634 void
 635 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 636                              struct cifs_pending_open *open)
 637 {
 638 #ifdef CONFIG_CIFS_SMB2
 639         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 640 #endif
 641         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 642         open->tlink = tlink;
 643         fid->pending_open = open;
 644         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 645 }
 646
 647 void
 648 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 649                       struct cifs_pending_open *open)
 650 {
 651         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 652         cifs_add_pending_open_locked(fid, tlink, open);
 653         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 654 }