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 #ifdef CONFIG_CIFS_STATS
 124                 spin_lock_init(&ret_buf->stat_lock);
 125 #endif
 126         }
 127         return ret_buf;
 128 }
 129
 130 void
 131 tconInfoFree(struct cifs_tcon *buf_to_free)
 132 {
 133         if (buf_to_free == NULL) {
 134                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 135                 return;
 136         }
 137         atomic_dec(&tconInfoAllocCount);
 138         kfree(buf_to_free->nativeFileSystem);
 139         if (buf_to_free->password) {
 140                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 141                 kfree(buf_to_free->password);
 142         }
 143         kfree(buf_to_free);
 144 }
 145
 146 struct smb_hdr *
 147 cifs_buf_get(void)
 148 {
 149         struct smb_hdr *ret_buf = NULL;
 150         size_t buf_size = sizeof(struct smb_hdr);
 151
 152 #ifdef CONFIG_CIFS_SMB2
 153         /*
 154          * SMB2 header is bigger than CIFS one - no problems to clean some
 155          * more bytes for CIFS.
 156          */
 157         buf_size = sizeof(struct smb2_hdr);
 158 #endif
 159         /*
 160          * We could use negotiated size instead of max_msgsize -
 161          * but it may be more efficient to always alloc same size
 162          * albeit slightly larger than necessary and maxbuffersize
 163          * defaults to this and can not be bigger.
 164          */
 165         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 166
 167         /* clear the first few header bytes */
 168         /* for most paths, more is cleared in header_assemble */
 169         if (ret_buf) {
 170                 memset(ret_buf, 0, buf_size + 3);
 171                 atomic_inc(&bufAllocCount);
 172 #ifdef CONFIG_CIFS_STATS2
 173                 atomic_inc(&totBufAllocCount);
 174 #endif /* CONFIG_CIFS_STATS2 */
 175         }
 176
 177         return ret_buf;
 178 }
 179
 180 void
 181 cifs_buf_release(void *buf_to_free)
 182 {
 183         if (buf_to_free == NULL) {
 184                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 185                 return;
 186         }
 187         mempool_free(buf_to_free, cifs_req_poolp);
 188
 189         atomic_dec(&bufAllocCount);
 190         return;
 191 }
 192
 193 struct smb_hdr *
 194 cifs_small_buf_get(void)
 195 {
 196         struct smb_hdr *ret_buf = NULL;
 197
 198 /* We could use negotiated size instead of max_msgsize -
 199    but it may be more efficient to always alloc same size
 200    albeit slightly larger than necessary and maxbuffersize
 201    defaults to this and can not be bigger */
 202         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 203         if (ret_buf) {
 204         /* No need to clear memory here, cleared in header assemble */
 205         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 206                 atomic_inc(&smBufAllocCount);
 207 #ifdef CONFIG_CIFS_STATS2
 208                 atomic_inc(&totSmBufAllocCount);
 209 #endif /* CONFIG_CIFS_STATS2 */
 210
 211         }
 212         return ret_buf;
 213 }
 214
 215 void
 216 cifs_small_buf_release(void *buf_to_free)
 217 {
 218
 219         if (buf_to_free == NULL) {
 220                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 221                 return;
 222         }
 223         mempool_free(buf_to_free, cifs_sm_req_poolp);
 224
 225         atomic_dec(&smBufAllocCount);
 226         return;
 227 }
 228
 229 void
 230 free_rsp_buf(int resp_buftype, void *rsp)
 231 {
 232         if (resp_buftype == CIFS_SMALL_BUFFER)
 233                 cifs_small_buf_release(rsp);
 234         else if (resp_buftype == CIFS_LARGE_BUFFER)
 235                 cifs_buf_release(rsp);
 236 }
 237
 238 /* NB: MID can not be set if treeCon not passed in, in that
 239    case it is responsbility of caller to set the mid */
 240 void
 241 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 242                 const struct cifs_tcon *treeCon, int word_count
 243                 /* length of fixed section (word count) in two byte units  */)
 244 {
 245         char *temp = (char *) buffer;
 246
 247         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 248
 249         buffer->smb_buf_length = cpu_to_be32(
 250             (2 * word_count) + sizeof(struct smb_hdr) -
 251             4 /*  RFC 1001 length field does not count */  +
 252             2 /* for bcc field itself */) ;
 253
 254         buffer->Protocol[0] = 0xFF;
 255         buffer->Protocol[1] = 'S';
 256         buffer->Protocol[2] = 'M';
 257         buffer->Protocol[3] = 'B';
 258         buffer->Command = smb_command;
 259         buffer->Flags = 0x00;   /* case sensitive */
 260         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 261         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 262         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 263         if (treeCon) {
 264                 buffer->Tid = treeCon->tid;
 265                 if (treeCon->ses) {
 266                         if (treeCon->ses->capabilities & CAP_UNICODE)
 267                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 268                         if (treeCon->ses->capabilities & CAP_STATUS32)
 269                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 270
 271                         /* Uid is not converted */
 272                         buffer->Uid = treeCon->ses->Suid;
 273                         buffer->Mid = get_next_mid(treeCon->ses->server);
 274                 }
 275                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 276                         buffer->Flags2 |= SMBFLG2_DFS;
 277                 if (treeCon->nocase)
 278                         buffer->Flags  |= SMBFLG_CASELESS;
 279                 if ((treeCon->ses) && (treeCon->ses->server))
 280                         if (treeCon->ses->server->sign)
 281                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 282         }
 283
 284 /*  endian conversion of flags is now done just before sending */
 285         buffer->WordCount = (char) word_count;
 286         return;
 287 }
 288
 289 static int
 290 check_smb_hdr(struct smb_hdr *smb)
 291 {
 292         /* does it have the right SMB "signature" ? */
 293         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 294                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 295                          *(unsigned int *)smb->Protocol);
 296                 return 1;
 297         }
 298
 299         /* if it's a response then accept */
 300         if (smb->Flags & SMBFLG_RESPONSE)
 301                 return 0;
 302
 303         /* only one valid case where server sends us request */
 304         if (smb->Command == SMB_COM_LOCKING_ANDX)
 305                 return 0;
 306
 307         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 308                  get_mid(smb));
 309         return 1;
 310 }
 311
 312 int
 313 checkSMB(char *buf, unsigned int total_read)
 314 {
 315         struct smb_hdr *smb = (struct smb_hdr *)buf;
 316         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 317         __u32 clc_len;  /* calculated length */
 318         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 319                  total_read, rfclen);
 320
 321         /* is this frame too small to even get to a BCC? */
 322         if (total_read < 2 + sizeof(struct smb_hdr)) {
 323                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 324                             && (smb->Status.CifsError != 0)) {
 325                         /* it's an error return */
 326                         smb->WordCount = 0;
 327                         /* some error cases do not return wct and bcc */
 328                         return 0;
 329                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 330                                 (smb->WordCount == 0)) {
 331                         char *tmp = (char *)smb;
 332                         /* Need to work around a bug in two servers here */
 333                         /* First, check if the part of bcc they sent was zero */
 334                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 335                                 /* some servers return only half of bcc
 336                                  * on simple responses (wct, bcc both zero)
 337                                  * in particular have seen this on
 338                                  * ulogoffX and FindClose. This leaves
 339                                  * one byte of bcc potentially unitialized
 340                                  */
 341                                 /* zero rest of bcc */
 342                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 343                                 return 0;
 344                         }
 345                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 346                 } else {
 347                         cifs_dbg(VFS, "Length less than smb header size\n");
 348                 }
 349                 return -EIO;
 350         }
 351
 352         /* otherwise, there is enough to get to the BCC */
 353         if (check_smb_hdr(smb))
 354                 return -EIO;
 355         clc_len = smbCalcSize(smb);
 356
 357         if (4 + rfclen != total_read) {
 358                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 359                          rfclen);
 360                 return -EIO;
 361         }
 362
 363         if (4 + rfclen != clc_len) {
 364                 __u16 mid = get_mid(smb);
 365                 /* check if bcc wrapped around for large read responses */
 366                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 367                         /* check if lengths match mod 64K */
 368                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 369                                 return 0; /* bcc wrapped */
 370                 }
 371                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 372                          clc_len, 4 + rfclen, mid);
 373
 374                 if (4 + rfclen < clc_len) {
 375                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 376                                  rfclen, mid);
 377                         return -EIO;
 378                 } else if (rfclen > clc_len + 512) {
 379                         /*
 380                          * Some servers (Windows XP in particular) send more
 381                          * data than the lengths in the SMB packet would
 382                          * indicate on certain calls (byte range locks and
 383                          * trans2 find first calls in particular). While the
 384                          * client can handle such a frame by ignoring the
 385                          * trailing data, we choose limit the amount of extra
 386                          * data to 512 bytes.
 387                          */
 388                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 389                                  rfclen, mid);
 390                         return -EIO;
 391                 }
 392         }
 393         return 0;
 394 }
 395
 396 bool
 397 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 398 {
 399         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 400         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 401         struct list_head *tmp, *tmp1, *tmp2;
 402         struct cifs_ses *ses;
 403         struct cifs_tcon *tcon;
 404         struct cifsInodeInfo *pCifsInode;
 405         struct cifsFileInfo *netfile;
 406
 407         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 408         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 409            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 410                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 411                         (struct smb_com_transaction_change_notify_rsp *)buf;
 412                 struct file_notify_information *pnotify;
 413                 __u32 data_offset = 0;
 414                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 415                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 416
 417                         pnotify = (struct file_notify_information *)
 418                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 419                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 420                                  pnotify->FileName, pnotify->Action);
 421                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 422                                 sizeof(struct smb_hdr)+60); */
 423                         return true;
 424                 }
 425                 if (pSMBr->hdr.Status.CifsError) {
 426                         cifs_dbg(FYI, "notify err 0x%x\n",
 427                                  pSMBr->hdr.Status.CifsError);
 428                         return true;
 429                 }
 430                 return false;
 431         }
 432         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 433                 return false;
 434         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 435                 /* no sense logging error on invalid handle on oplock
 436                    break - harmless race between close request and oplock
 437                    break response is expected from time to time writing out
 438                    large dirty files cached on the client */
 439                 if ((NT_STATUS_INVALID_HANDLE) ==
 440                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 441                         cifs_dbg(FYI, "invalid handle on oplock break\n");
 442                         return true;
 443                 } else if (ERRbadfid ==
 444                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 445                         return true;
 446                 } else {
 447                         return false; /* on valid oplock brk we get "request" */
 448                 }
 449         }
 450         if (pSMB->hdr.WordCount != 8)
 451                 return false;
 452
 453         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 454                  pSMB->LockType, pSMB->OplockLevel);
 455         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 456                 return false;
 457
 458         /* look up tcon based on tid & uid */
 459         spin_lock(&cifs_tcp_ses_lock);
 460         list_for_each(tmp, &srv->smb_ses_list) {
 461                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 462                 list_for_each(tmp1, &ses->tcon_list) {
 463                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 464                         if (tcon->tid != buf->Tid)
 465                                 continue;
 466
 467                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 468                         spin_lock(&cifs_file_list_lock);
 469                         list_for_each(tmp2, &tcon->openFileList) {
 470                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 471                                                      tlist);
 472                                 if (pSMB->Fid != netfile->fid.netfid)
 473                                         continue;
 474
 475                                 cifs_dbg(FYI, "file id match, oplock break\n");
 476                                 pCifsInode = CIFS_I(netfile->dentry->d_inode);
 477
 478                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 479                                         &pCifsInode->flags);
 480
 481                                 /*
 482                                  * Set flag if the server downgrades the oplock
 483                                  * to L2 else clear.
 484                                  */
 485                                 if (pSMB->OplockLevel)
 486                                         set_bit(
 487                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 488                                            &pCifsInode->flags);
 489                                 else
 490                                         clear_bit(
 491                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 492                                            &pCifsInode->flags);
 493
 494                                 queue_work(cifsiod_wq,
 495                                            &netfile->oplock_break);
 496                                 netfile->oplock_break_cancelled = false;
 497
 498                                 spin_unlock(&cifs_file_list_lock);
 499                                 spin_unlock(&cifs_tcp_ses_lock);
 500                                 return true;
 501                         }
 502                         spin_unlock(&cifs_file_list_lock);
 503                         spin_unlock(&cifs_tcp_ses_lock);
 504                         cifs_dbg(FYI, "No matching file for oplock break\n");
 505                         return true;
 506                 }
 507         }
 508         spin_unlock(&cifs_tcp_ses_lock);
 509         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 510         return true;
 511 }
 512
 513 void
 514 dump_smb(void *buf, int smb_buf_length)
 515 {
 516         int i, j;
 517         char debug_line[17];
 518         unsigned char *buffer = buf;
 519
 520         if (traceSMB == 0)
 521                 return;
 522
 523         for (i = 0, j = 0; i < smb_buf_length; i++, j++) {
 524                 if (i % 8 == 0) {
 525                         /* have reached the beginning of line */
 526                         printk(KERN_DEBUG "| ");
 527                         j = 0;
 528                 }
 529                 printk("%0#4x ", buffer[i]);
 530                 debug_line[2 * j] = ' ';
 531                 if (isprint(buffer[i]))
 532                         debug_line[1 + (2 * j)] = buffer[i];
 533                 else
 534                         debug_line[1 + (2 * j)] = '_';
 535
 536                 if (i % 8 == 7) {
 537                         /* reached end of line, time to print ascii */
 538                         debug_line[16] = 0;
 539                         printk(" | %s\n", debug_line);
 540                 }
 541         }
 542         for (; j < 8; j++) {
 543                 printk("     ");
 544                 debug_line[2 * j] = ' ';
 545                 debug_line[1 + (2 * j)] = ' ';
 546         }
 547         printk(" | %s\n", debug_line);
 548         return;
 549 }
 550
 551 void
 552 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 553 {
 554         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 555                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 556                 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",
 557                          cifs_sb_master_tcon(cifs_sb)->treeName);
 558         }
 559 }
 560
 561 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 562 {
 563         oplock &= 0xF;
 564
 565         if (oplock == OPLOCK_EXCLUSIVE) {
 566                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 567                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 568                          &cinode->vfs_inode);
 569         } else if (oplock == OPLOCK_READ) {
 570                 cinode->oplock = CIFS_CACHE_READ_FLG;
 571                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 572                          &cinode->vfs_inode);
 573         } else
 574                 cinode->oplock = 0;
 575 }
 576
 577 /*
 578  * We wait for oplock breaks to be processed before we attempt to perform
 579  * writes.
 580  */
 581 int cifs_get_writer(struct cifsInodeInfo *cinode)
 582 {
 583         int rc;
 584
 585 start:
 586         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 587                          TASK_KILLABLE);
 588         if (rc)
 589                 return rc;
 590
 591         spin_lock(&cinode->writers_lock);
 592         if (!cinode->writers)
 593                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 594         cinode->writers++;
 595         /* Check to see if we have started servicing an oplock break */
 596         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 597                 cinode->writers--;
 598                 if (cinode->writers == 0) {
 599                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 600                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 601                 }
 602                 spin_unlock(&cinode->writers_lock);
 603                 goto start;
 604         }
 605         spin_unlock(&cinode->writers_lock);
 606         return 0;
 607 }
 608
 609 void cifs_put_writer(struct cifsInodeInfo *cinode)
 610 {
 611         spin_lock(&cinode->writers_lock);
 612         cinode->writers--;
 613         if (cinode->writers == 0) {
 614                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 615                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 616         }
 617         spin_unlock(&cinode->writers_lock);
 618 }
 619
 620 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 621 {
 622         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 623         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 624 }
 625
 626 bool
 627 backup_cred(struct cifs_sb_info *cifs_sb)
 628 {
 629         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 630                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 631                         return true;
 632         }
 633         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 634                 if (in_group_p(cifs_sb->mnt_backupgid))
 635                         return true;
 636         }
 637
 638         return false;
 639 }
 640
 641 void
 642 cifs_del_pending_open(struct cifs_pending_open *open)
 643 {
 644         spin_lock(&cifs_file_list_lock);
 645         list_del(&open->olist);
 646         spin_unlock(&cifs_file_list_lock);
 647 }
 648
 649 void
 650 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 651                              struct cifs_pending_open *open)
 652 {
 653 #ifdef CONFIG_CIFS_SMB2
 654         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 655 #endif
 656         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 657         open->tlink = tlink;
 658         fid->pending_open = open;
 659         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 660 }
 661
 662 void
 663 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 664                       struct cifs_pending_open *open)
 665 {
 666         spin_lock(&cifs_file_list_lock);
 667         cifs_add_pending_open_locked(fid, tlink, open);
 668         spin_unlock(&cifs_file_list_lock);
 669 }