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         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         return ret_buf;
 177 }
 178
 179 void
 180 cifs_buf_release(void *buf_to_free)
 181 {
 182         if (buf_to_free == NULL) {
 183                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 184                 return;
 185         }
 186         mempool_free(buf_to_free, cifs_req_poolp);
 187
 188         atomic_dec(&bufAllocCount);
 189         return;
 190 }
 191
 192 struct smb_hdr *
 193 cifs_small_buf_get(void)
 194 {
 195         struct smb_hdr *ret_buf = NULL;
 196
 197 /* We could use negotiated size instead of max_msgsize -
 198    but it may be more efficient to always alloc same size
 199    albeit slightly larger than necessary and maxbuffersize
 200    defaults to this and can not be bigger */
 201         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 202         /* No need to clear memory here, cleared in header assemble */
 203         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 204         atomic_inc(&smBufAllocCount);
 205 #ifdef CONFIG_CIFS_STATS2
 206         atomic_inc(&totSmBufAllocCount);
 207 #endif /* CONFIG_CIFS_STATS2 */
 208
 209         return ret_buf;
 210 }
 211
 212 void
 213 cifs_small_buf_release(void *buf_to_free)
 214 {
 215
 216         if (buf_to_free == NULL) {
 217                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 218                 return;
 219         }
 220         mempool_free(buf_to_free, cifs_sm_req_poolp);
 221
 222         atomic_dec(&smBufAllocCount);
 223         return;
 224 }
 225
 226 void
 227 free_rsp_buf(int resp_buftype, void *rsp)
 228 {
 229         if (resp_buftype == CIFS_SMALL_BUFFER)
 230                 cifs_small_buf_release(rsp);
 231         else if (resp_buftype == CIFS_LARGE_BUFFER)
 232                 cifs_buf_release(rsp);
 233 }
 234
 235 /* NB: MID can not be set if treeCon not passed in, in that
 236    case it is responsbility of caller to set the mid */
 237 void
 238 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 239                 const struct cifs_tcon *treeCon, int word_count
 240                 /* length of fixed section (word count) in two byte units  */)
 241 {
 242         char *temp = (char *) buffer;
 243
 244         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 245
 246         buffer->smb_buf_length = cpu_to_be32(
 247             (2 * word_count) + sizeof(struct smb_hdr) -
 248             4 /*  RFC 1001 length field does not count */  +
 249             2 /* for bcc field itself */) ;
 250
 251         buffer->Protocol[0] = 0xFF;
 252         buffer->Protocol[1] = 'S';
 253         buffer->Protocol[2] = 'M';
 254         buffer->Protocol[3] = 'B';
 255         buffer->Command = smb_command;
 256         buffer->Flags = 0x00;   /* case sensitive */
 257         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 258         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 259         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 260         if (treeCon) {
 261                 buffer->Tid = treeCon->tid;
 262                 if (treeCon->ses) {
 263                         if (treeCon->ses->capabilities & CAP_UNICODE)
 264                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 265                         if (treeCon->ses->capabilities & CAP_STATUS32)
 266                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 267
 268                         /* Uid is not converted */
 269                         buffer->Uid = treeCon->ses->Suid;
 270                         buffer->Mid = get_next_mid(treeCon->ses->server);
 271                 }
 272                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 273                         buffer->Flags2 |= SMBFLG2_DFS;
 274                 if (treeCon->nocase)
 275                         buffer->Flags  |= SMBFLG_CASELESS;
 276                 if ((treeCon->ses) && (treeCon->ses->server))
 277                         if (treeCon->ses->server->sign)
 278                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 279         }
 280
 281 /*  endian conversion of flags is now done just before sending */
 282         buffer->WordCount = (char) word_count;
 283         return;
 284 }
 285
 286 static int
 287 check_smb_hdr(struct smb_hdr *smb)
 288 {
 289         /* does it have the right SMB "signature" ? */
 290         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 291                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 292                          *(unsigned int *)smb->Protocol);
 293                 return 1;
 294         }
 295
 296         /* if it's a response then accept */
 297         if (smb->Flags & SMBFLG_RESPONSE)
 298                 return 0;
 299
 300         /* only one valid case where server sends us request */
 301         if (smb->Command == SMB_COM_LOCKING_ANDX)
 302                 return 0;
 303
 304         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 305                  get_mid(smb));
 306         return 1;
 307 }
 308
 309 int
 310 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 311 {
 312         struct smb_hdr *smb = (struct smb_hdr *)buf;
 313         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 314         __u32 clc_len;  /* calculated length */
 315         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 316                  total_read, rfclen);
 317
 318         /* is this frame too small to even get to a BCC? */
 319         if (total_read < 2 + sizeof(struct smb_hdr)) {
 320                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 321                             && (smb->Status.CifsError != 0)) {
 322                         /* it's an error return */
 323                         smb->WordCount = 0;
 324                         /* some error cases do not return wct and bcc */
 325                         return 0;
 326                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 327                                 (smb->WordCount == 0)) {
 328                         char *tmp = (char *)smb;
 329                         /* Need to work around a bug in two servers here */
 330                         /* First, check if the part of bcc they sent was zero */
 331                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 332                                 /* some servers return only half of bcc
 333                                  * on simple responses (wct, bcc both zero)
 334                                  * in particular have seen this on
 335                                  * ulogoffX and FindClose. This leaves
 336                                  * one byte of bcc potentially unitialized
 337                                  */
 338                                 /* zero rest of bcc */
 339                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 340                                 return 0;
 341                         }
 342                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 343                 } else {
 344                         cifs_dbg(VFS, "Length less than smb header size\n");
 345                 }
 346                 return -EIO;
 347         }
 348
 349         /* otherwise, there is enough to get to the BCC */
 350         if (check_smb_hdr(smb))
 351                 return -EIO;
 352         clc_len = smbCalcSize(smb);
 353
 354         if (4 + rfclen != total_read) {
 355                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 356                          rfclen);
 357                 return -EIO;
 358         }
 359
 360         if (4 + rfclen != clc_len) {
 361                 __u16 mid = get_mid(smb);
 362                 /* check if bcc wrapped around for large read responses */
 363                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 364                         /* check if lengths match mod 64K */
 365                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 366                                 return 0; /* bcc wrapped */
 367                 }
 368                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 369                          clc_len, 4 + rfclen, mid);
 370
 371                 if (4 + rfclen < clc_len) {
 372                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 373                                  rfclen, mid);
 374                         return -EIO;
 375                 } else if (rfclen > clc_len + 512) {
 376                         /*
 377                          * Some servers (Windows XP in particular) send more
 378                          * data than the lengths in the SMB packet would
 379                          * indicate on certain calls (byte range locks and
 380                          * trans2 find first calls in particular). While the
 381                          * client can handle such a frame by ignoring the
 382                          * trailing data, we choose limit the amount of extra
 383                          * data to 512 bytes.
 384                          */
 385                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 386                                  rfclen, mid);
 387                         return -EIO;
 388                 }
 389         }
 390         return 0;
 391 }
 392
 393 bool
 394 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 395 {
 396         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 397         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 398         struct list_head *tmp, *tmp1, *tmp2;
 399         struct cifs_ses *ses;
 400         struct cifs_tcon *tcon;
 401         struct cifsInodeInfo *pCifsInode;
 402         struct cifsFileInfo *netfile;
 403
 404         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 405         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 406            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 407                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 408                         (struct smb_com_transaction_change_notify_rsp *)buf;
 409                 struct file_notify_information *pnotify;
 410                 __u32 data_offset = 0;
 411                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 412                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 413
 414                         pnotify = (struct file_notify_information *)
 415                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 416                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 417                                  pnotify->FileName, pnotify->Action);
 418                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 419                                 sizeof(struct smb_hdr)+60); */
 420                         return true;
 421                 }
 422                 if (pSMBr->hdr.Status.CifsError) {
 423                         cifs_dbg(FYI, "notify err 0x%x\n",
 424                                  pSMBr->hdr.Status.CifsError);
 425                         return true;
 426                 }
 427                 return false;
 428         }
 429         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 430                 return false;
 431         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 432                 /* no sense logging error on invalid handle on oplock
 433                    break - harmless race between close request and oplock
 434                    break response is expected from time to time writing out
 435                    large dirty files cached on the client */
 436                 if ((NT_STATUS_INVALID_HANDLE) ==
 437                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 438                         cifs_dbg(FYI, "invalid handle on oplock break\n");
 439                         return true;
 440                 } else if (ERRbadfid ==
 441                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 442                         return true;
 443                 } else {
 444                         return false; /* on valid oplock brk we get "request" */
 445                 }
 446         }
 447         if (pSMB->hdr.WordCount != 8)
 448                 return false;
 449
 450         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 451                  pSMB->LockType, pSMB->OplockLevel);
 452         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 453                 return false;
 454
 455         /* look up tcon based on tid & uid */
 456         spin_lock(&cifs_tcp_ses_lock);
 457         list_for_each(tmp, &srv->smb_ses_list) {
 458                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 459                 list_for_each(tmp1, &ses->tcon_list) {
 460                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 461                         if (tcon->tid != buf->Tid)
 462                                 continue;
 463
 464                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 465                         spin_lock(&tcon->open_file_lock);
 466                         list_for_each(tmp2, &tcon->openFileList) {
 467                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 468                                                      tlist);
 469                                 if (pSMB->Fid != netfile->fid.netfid)
 470                                         continue;
 471
 472                                 cifs_dbg(FYI, "file id match, oplock break\n");
 473                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 474
 475                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 476                                         &pCifsInode->flags);
 477
 478                                 /*
 479                                  * Set flag if the server downgrades the oplock
 480                                  * to L2 else clear.
 481                                  */
 482                                 if (pSMB->OplockLevel)
 483                                         set_bit(
 484                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 485                                            &pCifsInode->flags);
 486                                 else
 487                                         clear_bit(
 488                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 489                                            &pCifsInode->flags);
 490
 491                                 queue_work(cifsiod_wq,
 492                                            &netfile->oplock_break);
 493                                 netfile->oplock_break_cancelled = false;
 494
 495                                 spin_unlock(&tcon->open_file_lock);
 496                                 spin_unlock(&cifs_tcp_ses_lock);
 497                                 return true;
 498                         }
 499                         spin_unlock(&tcon->open_file_lock);
 500                         spin_unlock(&cifs_tcp_ses_lock);
 501                         cifs_dbg(FYI, "No matching file for oplock break\n");
 502                         return true;
 503                 }
 504         }
 505         spin_unlock(&cifs_tcp_ses_lock);
 506         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 507         return true;
 508 }
 509
 510 void
 511 dump_smb(void *buf, int smb_buf_length)
 512 {
 513         if (traceSMB == 0)
 514                 return;
 515
 516         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 517                        smb_buf_length, true);
 518 }
 519
 520 void
 521 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 522 {
 523         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 524                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 525                 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",
 526                          cifs_sb_master_tcon(cifs_sb)->treeName);
 527         }
 528 }
 529
 530 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 531 {
 532         oplock &= 0xF;
 533
 534         if (oplock == OPLOCK_EXCLUSIVE) {
 535                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 536                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 537                          &cinode->vfs_inode);
 538         } else if (oplock == OPLOCK_READ) {
 539                 cinode->oplock = CIFS_CACHE_READ_FLG;
 540                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 541                          &cinode->vfs_inode);
 542         } else
 543                 cinode->oplock = 0;
 544 }
 545
 546 /*
 547  * We wait for oplock breaks to be processed before we attempt to perform
 548  * writes.
 549  */
 550 int cifs_get_writer(struct cifsInodeInfo *cinode)
 551 {
 552         int rc;
 553
 554 start:
 555         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 556                          TASK_KILLABLE);
 557         if (rc)
 558                 return rc;
 559
 560         spin_lock(&cinode->writers_lock);
 561         if (!cinode->writers)
 562                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 563         cinode->writers++;
 564         /* Check to see if we have started servicing an oplock break */
 565         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 566                 cinode->writers--;
 567                 if (cinode->writers == 0) {
 568                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 569                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 570                 }
 571                 spin_unlock(&cinode->writers_lock);
 572                 goto start;
 573         }
 574         spin_unlock(&cinode->writers_lock);
 575         return 0;
 576 }
 577
 578 void cifs_put_writer(struct cifsInodeInfo *cinode)
 579 {
 580         spin_lock(&cinode->writers_lock);
 581         cinode->writers--;
 582         if (cinode->writers == 0) {
 583                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 584                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 585         }
 586         spin_unlock(&cinode->writers_lock);
 587 }
 588
 589 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 590 {
 591         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 592         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 593 }
 594
 595 bool
 596 backup_cred(struct cifs_sb_info *cifs_sb)
 597 {
 598         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 599                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 600                         return true;
 601         }
 602         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 603                 if (in_group_p(cifs_sb->mnt_backupgid))
 604                         return true;
 605         }
 606
 607         return false;
 608 }
 609
 610 void
 611 cifs_del_pending_open(struct cifs_pending_open *open)
 612 {
 613         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 614         list_del(&open->olist);
 615         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 616 }
 617
 618 void
 619 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 620                              struct cifs_pending_open *open)
 621 {
 622 #ifdef CONFIG_CIFS_SMB2
 623         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 624 #endif
 625         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 626         open->tlink = tlink;
 627         fid->pending_open = open;
 628         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 629 }
 630
 631 void
 632 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 633                       struct cifs_pending_open *open)
 634 {
 635         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 636         cifs_add_pending_open_locked(fid, tlink, open);
 637         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 638 }
 639
 640 /* parses DFS refferal V3 structure
 641  * caller is responsible for freeing target_nodes
 642  * returns:
 643  * - on success - 0
 644  * - on failure - errno
 645  */
 646 int
 647 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 648                     unsigned int *num_of_nodes,
 649                     struct dfs_info3_param **target_nodes,
 650                     const struct nls_table *nls_codepage, int remap,
 651                     const char *searchName, bool is_unicode)
 652 {
 653         int i, rc = 0;
 654         char *data_end;
 655         struct dfs_referral_level_3 *ref;
 656
 657         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 658
 659         if (*num_of_nodes < 1) {
 660                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 661                          *num_of_nodes);
 662                 rc = -EINVAL;
 663                 goto parse_DFS_referrals_exit;
 664         }
 665
 666         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 667         if (ref->VersionNumber != cpu_to_le16(3)) {
 668                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 669                          le16_to_cpu(ref->VersionNumber));
 670                 rc = -EINVAL;
 671                 goto parse_DFS_referrals_exit;
 672         }
 673
 674         /* get the upper boundary of the resp buffer */
 675         data_end = (char *)rsp + rsp_size;
 676
 677         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 678                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 679
 680         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 681                                 GFP_KERNEL);
 682         if (*target_nodes == NULL) {
 683                 rc = -ENOMEM;
 684                 goto parse_DFS_referrals_exit;
 685         }
 686
 687         /* collect necessary data from referrals */
 688         for (i = 0; i < *num_of_nodes; i++) {
 689                 char *temp;
 690                 int max_len;
 691                 struct dfs_info3_param *node = (*target_nodes)+i;
 692
 693                 node->flags = le32_to_cpu(rsp->DFSFlags);
 694                 if (is_unicode) {
 695                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 696                                                 GFP_KERNEL);
 697                         if (tmp == NULL) {
 698                                 rc = -ENOMEM;
 699                                 goto parse_DFS_referrals_exit;
 700                         }
 701                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 702                                            PATH_MAX, nls_codepage, remap);
 703                         node->path_consumed = cifs_utf16_bytes(tmp,
 704                                         le16_to_cpu(rsp->PathConsumed),
 705                                         nls_codepage);
 706                         kfree(tmp);
 707                 } else
 708                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 709
 710                 node->server_type = le16_to_cpu(ref->ServerType);
 711                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 712
 713                 /* copy DfsPath */
 714                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 715                 max_len = data_end - temp;
 716                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 717                                                 is_unicode, nls_codepage);
 718                 if (!node->path_name) {
 719                         rc = -ENOMEM;
 720                         goto parse_DFS_referrals_exit;
 721                 }
 722
 723                 /* copy link target UNC */
 724                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 725                 max_len = data_end - temp;
 726                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 727                                                 is_unicode, nls_codepage);
 728                 if (!node->node_name) {
 729                         rc = -ENOMEM;
 730                         goto parse_DFS_referrals_exit;
 731                 }
 732
 733                 ref++;
 734         }
 735
 736 parse_DFS_referrals_exit:
 737         if (rc) {
 738                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 739                 *target_nodes = NULL;
 740                 *num_of_nodes = 0;
 741         }
 742         return rc;
 743 }