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 <linux/vmalloc.h>
  26 #include "cifspdu.h"
  27 #include "cifsglob.h"
  28 #include "cifsproto.h"
  29 #include "cifs_debug.h"
  30 #include "smberr.h"
  31 #include "nterr.h"
  32 #include "cifs_unicode.h"
  33 #include "smb2pdu.h"
  34
  35 extern mempool_t *cifs_sm_req_poolp;
  36 extern mempool_t *cifs_req_poolp;
  37
  38 /* The xid serves as a useful identifier for each incoming vfs request,
  39    in a similar way to the mid which is useful to track each sent smb,
  40    and CurrentXid can also provide a running counter (although it
  41    will eventually wrap past zero) of the total vfs operations handled
  42    since the cifs fs was mounted */
  43
  44 unsigned int
  45 _get_xid(void)
  46 {
  47         unsigned int xid;
  48
  49         spin_lock(&GlobalMid_Lock);
  50         GlobalTotalActiveXid++;
  51
  52         /* keep high water mark for number of simultaneous ops in filesystem */
  53         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  54                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  55         if (GlobalTotalActiveXid > 65000)
  56                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  57         xid = GlobalCurrentXid++;
  58         spin_unlock(&GlobalMid_Lock);
  59         return xid;
  60 }
  61
  62 void
  63 _free_xid(unsigned int xid)
  64 {
  65         spin_lock(&GlobalMid_Lock);
  66         /* if (GlobalTotalActiveXid == 0)
  67                 BUG(); */
  68         GlobalTotalActiveXid--;
  69         spin_unlock(&GlobalMid_Lock);
  70 }
  71
  72 struct cifs_ses *
  73 sesInfoAlloc(void)
  74 {
  75         struct cifs_ses *ret_buf;
  76
  77         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  78         if (ret_buf) {
  79                 atomic_inc(&sesInfoAllocCount);
  80                 ret_buf->status = CifsNew;
  81                 ++ret_buf->ses_count;
  82                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  83                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  84                 mutex_init(&ret_buf->session_mutex);
  85                 spin_lock_init(&ret_buf->iface_lock);
  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         kfree(buf_to_free->iface_list);
 107         kzfree(buf_to_free);
 108 }
 109
 110 struct cifs_tcon *
 111 tconInfoAlloc(void)
 112 {
 113         struct cifs_tcon *ret_buf;
 114         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
 115         if (ret_buf) {
 116                 atomic_inc(&tconInfoAllocCount);
 117                 ret_buf->tidStatus = CifsNew;
 118                 ++ret_buf->tc_count;
 119                 INIT_LIST_HEAD(&ret_buf->openFileList);
 120                 INIT_LIST_HEAD(&ret_buf->tcon_list);
 121                 spin_lock_init(&ret_buf->open_file_lock);
 122                 mutex_init(&ret_buf->crfid.fid_mutex);
 123                 ret_buf->crfid.fid = kzalloc(sizeof(struct cifs_fid),
 124                                              GFP_KERNEL);
 125                 spin_lock_init(&ret_buf->stat_lock);
 126                 atomic_set(&ret_buf->num_local_opens, 0);
 127                 atomic_set(&ret_buf->num_remote_opens, 0);
 128         }
 129         return ret_buf;
 130 }
 131
 132 void
 133 tconInfoFree(struct cifs_tcon *buf_to_free)
 134 {
 135         if (buf_to_free == NULL) {
 136                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 137                 return;
 138         }
 139         atomic_dec(&tconInfoAllocCount);
 140         kfree(buf_to_free->nativeFileSystem);
 141         kzfree(buf_to_free->password);
 142         kfree(buf_to_free->crfid.fid);
 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         /*
 151          * SMB2 header is bigger than CIFS one - no problems to clean some
 152          * more bytes for CIFS.
 153          */
 154         size_t buf_size = sizeof(struct smb2_sync_hdr);
 155
 156         /*
 157          * We could use negotiated size instead of max_msgsize -
 158          * but it may be more efficient to always alloc same size
 159          * albeit slightly larger than necessary and maxbuffersize
 160          * defaults to this and can not be bigger.
 161          */
 162         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 163
 164         /* clear the first few header bytes */
 165         /* for most paths, more is cleared in header_assemble */
 166         memset(ret_buf, 0, buf_size + 3);
 167         atomic_inc(&bufAllocCount);
 168 #ifdef CONFIG_CIFS_STATS2
 169         atomic_inc(&totBufAllocCount);
 170 #endif /* CONFIG_CIFS_STATS2 */
 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         /* No need to clear memory here, cleared in header assemble */
 199         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 200         atomic_inc(&smBufAllocCount);
 201 #ifdef CONFIG_CIFS_STATS2
 202         atomic_inc(&totSmBufAllocCount);
 203 #endif /* CONFIG_CIFS_STATS2 */
 204
 205         return ret_buf;
 206 }
 207
 208 void
 209 cifs_small_buf_release(void *buf_to_free)
 210 {
 211
 212         if (buf_to_free == NULL) {
 213                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 214                 return;
 215         }
 216         mempool_free(buf_to_free, cifs_sm_req_poolp);
 217
 218         atomic_dec(&smBufAllocCount);
 219         return;
 220 }
 221
 222 void
 223 free_rsp_buf(int resp_buftype, void *rsp)
 224 {
 225         if (resp_buftype == CIFS_SMALL_BUFFER)
 226                 cifs_small_buf_release(rsp);
 227         else if (resp_buftype == CIFS_LARGE_BUFFER)
 228                 cifs_buf_release(rsp);
 229 }
 230
 231 /* NB: MID can not be set if treeCon not passed in, in that
 232    case it is responsbility of caller to set the mid */
 233 void
 234 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 235                 const struct cifs_tcon *treeCon, int word_count
 236                 /* length of fixed section (word count) in two byte units  */)
 237 {
 238         char *temp = (char *) buffer;
 239
 240         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 241
 242         buffer->smb_buf_length = cpu_to_be32(
 243             (2 * word_count) + sizeof(struct smb_hdr) -
 244             4 /*  RFC 1001 length field does not count */  +
 245             2 /* for bcc field itself */) ;
 246
 247         buffer->Protocol[0] = 0xFF;
 248         buffer->Protocol[1] = 'S';
 249         buffer->Protocol[2] = 'M';
 250         buffer->Protocol[3] = 'B';
 251         buffer->Command = smb_command;
 252         buffer->Flags = 0x00;   /* case sensitive */
 253         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 254         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 255         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 256         if (treeCon) {
 257                 buffer->Tid = treeCon->tid;
 258                 if (treeCon->ses) {
 259                         if (treeCon->ses->capabilities & CAP_UNICODE)
 260                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 261                         if (treeCon->ses->capabilities & CAP_STATUS32)
 262                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 263
 264                         /* Uid is not converted */
 265                         buffer->Uid = treeCon->ses->Suid;
 266                         buffer->Mid = get_next_mid(treeCon->ses->server);
 267                 }
 268                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 269                         buffer->Flags2 |= SMBFLG2_DFS;
 270                 if (treeCon->nocase)
 271                         buffer->Flags  |= SMBFLG_CASELESS;
 272                 if ((treeCon->ses) && (treeCon->ses->server))
 273                         if (treeCon->ses->server->sign)
 274                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 275         }
 276
 277 /*  endian conversion of flags is now done just before sending */
 278         buffer->WordCount = (char) word_count;
 279         return;
 280 }
 281
 282 static int
 283 check_smb_hdr(struct smb_hdr *smb)
 284 {
 285         /* does it have the right SMB "signature" ? */
 286         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 287                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 288                          *(unsigned int *)smb->Protocol);
 289                 return 1;
 290         }
 291
 292         /* if it's a response then accept */
 293         if (smb->Flags & SMBFLG_RESPONSE)
 294                 return 0;
 295
 296         /* only one valid case where server sends us request */
 297         if (smb->Command == SMB_COM_LOCKING_ANDX)
 298                 return 0;
 299
 300         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 301                  get_mid(smb));
 302         return 1;
 303 }
 304
 305 int
 306 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 307 {
 308         struct smb_hdr *smb = (struct smb_hdr *)buf;
 309         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 310         __u32 clc_len;  /* calculated length */
 311         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 312                  total_read, rfclen);
 313
 314         /* is this frame too small to even get to a BCC? */
 315         if (total_read < 2 + sizeof(struct smb_hdr)) {
 316                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 317                             && (smb->Status.CifsError != 0)) {
 318                         /* it's an error return */
 319                         smb->WordCount = 0;
 320                         /* some error cases do not return wct and bcc */
 321                         return 0;
 322                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 323                                 (smb->WordCount == 0)) {
 324                         char *tmp = (char *)smb;
 325                         /* Need to work around a bug in two servers here */
 326                         /* First, check if the part of bcc they sent was zero */
 327                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 328                                 /* some servers return only half of bcc
 329                                  * on simple responses (wct, bcc both zero)
 330                                  * in particular have seen this on
 331                                  * ulogoffX and FindClose. This leaves
 332                                  * one byte of bcc potentially unitialized
 333                                  */
 334                                 /* zero rest of bcc */
 335                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 336                                 return 0;
 337                         }
 338                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 339                 } else {
 340                         cifs_dbg(VFS, "Length less than smb header size\n");
 341                 }
 342                 return -EIO;
 343         }
 344
 345         /* otherwise, there is enough to get to the BCC */
 346         if (check_smb_hdr(smb))
 347                 return -EIO;
 348         clc_len = smbCalcSize(smb, server);
 349
 350         if (4 + rfclen != total_read) {
 351                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 352                          rfclen);
 353                 return -EIO;
 354         }
 355
 356         if (4 + rfclen != clc_len) {
 357                 __u16 mid = get_mid(smb);
 358                 /* check if bcc wrapped around for large read responses */
 359                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 360                         /* check if lengths match mod 64K */
 361                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 362                                 return 0; /* bcc wrapped */
 363                 }
 364                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 365                          clc_len, 4 + rfclen, mid);
 366
 367                 if (4 + rfclen < clc_len) {
 368                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 369                                  rfclen, mid);
 370                         return -EIO;
 371                 } else if (rfclen > clc_len + 512) {
 372                         /*
 373                          * Some servers (Windows XP in particular) send more
 374                          * data than the lengths in the SMB packet would
 375                          * indicate on certain calls (byte range locks and
 376                          * trans2 find first calls in particular). While the
 377                          * client can handle such a frame by ignoring the
 378                          * trailing data, we choose limit the amount of extra
 379                          * data to 512 bytes.
 380                          */
 381                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 382                                  rfclen, mid);
 383                         return -EIO;
 384                 }
 385         }
 386         return 0;
 387 }
 388
 389 bool
 390 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 391 {
 392         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 393         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 394         struct list_head *tmp, *tmp1, *tmp2;
 395         struct cifs_ses *ses;
 396         struct cifs_tcon *tcon;
 397         struct cifsInodeInfo *pCifsInode;
 398         struct cifsFileInfo *netfile;
 399
 400         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 401         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 402            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 403                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 404                         (struct smb_com_transaction_change_notify_rsp *)buf;
 405                 struct file_notify_information *pnotify;
 406                 __u32 data_offset = 0;
 407                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 408
 409                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 410                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 411
 412                         if (data_offset >
 413                             len - sizeof(struct file_notify_information)) {
 414                                 cifs_dbg(FYI, "invalid data_offset %u\n",
 415                                          data_offset);
 416                                 return true;
 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(cifsoplockd_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         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 627         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 628         open->tlink = tlink;
 629         fid->pending_open = open;
 630         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 631 }
 632
 633 void
 634 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 635                       struct cifs_pending_open *open)
 636 {
 637         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 638         cifs_add_pending_open_locked(fid, tlink, open);
 639         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 640 }
 641
 642 /* parses DFS refferal V3 structure
 643  * caller is responsible for freeing target_nodes
 644  * returns:
 645  * - on success - 0
 646  * - on failure - errno
 647  */
 648 int
 649 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 650                     unsigned int *num_of_nodes,
 651                     struct dfs_info3_param **target_nodes,
 652                     const struct nls_table *nls_codepage, int remap,
 653                     const char *searchName, bool is_unicode)
 654 {
 655         int i, rc = 0;
 656         char *data_end;
 657         struct dfs_referral_level_3 *ref;
 658
 659         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 660
 661         if (*num_of_nodes < 1) {
 662                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 663                          *num_of_nodes);
 664                 rc = -EINVAL;
 665                 goto parse_DFS_referrals_exit;
 666         }
 667
 668         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 669         if (ref->VersionNumber != cpu_to_le16(3)) {
 670                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 671                          le16_to_cpu(ref->VersionNumber));
 672                 rc = -EINVAL;
 673                 goto parse_DFS_referrals_exit;
 674         }
 675
 676         /* get the upper boundary of the resp buffer */
 677         data_end = (char *)rsp + rsp_size;
 678
 679         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 680                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 681
 682         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 683                                 GFP_KERNEL);
 684         if (*target_nodes == NULL) {
 685                 rc = -ENOMEM;
 686                 goto parse_DFS_referrals_exit;
 687         }
 688
 689         /* collect necessary data from referrals */
 690         for (i = 0; i < *num_of_nodes; i++) {
 691                 char *temp;
 692                 int max_len;
 693                 struct dfs_info3_param *node = (*target_nodes)+i;
 694
 695                 node->flags = le32_to_cpu(rsp->DFSFlags);
 696                 if (is_unicode) {
 697                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 698                                                 GFP_KERNEL);
 699                         if (tmp == NULL) {
 700                                 rc = -ENOMEM;
 701                                 goto parse_DFS_referrals_exit;
 702                         }
 703                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 704                                            PATH_MAX, nls_codepage, remap);
 705                         node->path_consumed = cifs_utf16_bytes(tmp,
 706                                         le16_to_cpu(rsp->PathConsumed),
 707                                         nls_codepage);
 708                         kfree(tmp);
 709                 } else
 710                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 711
 712                 node->server_type = le16_to_cpu(ref->ServerType);
 713                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 714
 715                 /* copy DfsPath */
 716                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 717                 max_len = data_end - temp;
 718                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 719                                                 is_unicode, nls_codepage);
 720                 if (!node->path_name) {
 721                         rc = -ENOMEM;
 722                         goto parse_DFS_referrals_exit;
 723                 }
 724
 725                 /* copy link target UNC */
 726                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 727                 max_len = data_end - temp;
 728                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 729                                                 is_unicode, nls_codepage);
 730                 if (!node->node_name) {
 731                         rc = -ENOMEM;
 732                         goto parse_DFS_referrals_exit;
 733                 }
 734
 735                 ref++;
 736         }
 737
 738 parse_DFS_referrals_exit:
 739         if (rc) {
 740                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 741                 *target_nodes = NULL;
 742                 *num_of_nodes = 0;
 743         }
 744         return rc;
 745 }
 746
 747 struct cifs_aio_ctx *
 748 cifs_aio_ctx_alloc(void)
 749 {
 750         struct cifs_aio_ctx *ctx;
 751
 752         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 753         if (!ctx)
 754                 return NULL;
 755
 756         INIT_LIST_HEAD(&ctx->list);
 757         mutex_init(&ctx->aio_mutex);
 758         init_completion(&ctx->done);
 759         kref_init(&ctx->refcount);
 760         return ctx;
 761 }
 762
 763 void
 764 cifs_aio_ctx_release(struct kref *refcount)
 765 {
 766         struct cifs_aio_ctx *ctx = container_of(refcount,
 767                                         struct cifs_aio_ctx, refcount);
 768
 769         cifsFileInfo_put(ctx->cfile);
 770         kvfree(ctx->bv);
 771         kfree(ctx);
 772 }
 773
 774 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
 775
 776 int
 777 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 778 {
 779         ssize_t rc;
 780         unsigned int cur_npages;
 781         unsigned int npages = 0;
 782         unsigned int i;
 783         size_t len;
 784         size_t count = iov_iter_count(iter);
 785         unsigned int saved_len;
 786         size_t start;
 787         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
 788         struct page **pages = NULL;
 789         struct bio_vec *bv = NULL;
 790
 791         if (iov_iter_is_kvec(iter)) {
 792                 memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
 793                 ctx->len = count;
 794                 iov_iter_advance(iter, count);
 795                 return 0;
 796         }
 797
 798         if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
 799                 bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
 800                                    GFP_KERNEL);
 801
 802         if (!bv) {
 803                 bv = vmalloc(array_size(max_pages, sizeof(struct bio_vec)));
 804                 if (!bv)
 805                         return -ENOMEM;
 806         }
 807
 808         if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
 809                 pages = kmalloc_array(max_pages, sizeof(struct page *),
 810                                       GFP_KERNEL);
 811
 812         if (!pages) {
 813                 pages = vmalloc(array_size(max_pages, sizeof(struct page *)));
 814                 if (!pages) {
 815                         kvfree(bv);
 816                         return -ENOMEM;
 817                 }
 818         }
 819
 820         saved_len = count;
 821
 822         while (count && npages < max_pages) {
 823                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
 824                 if (rc < 0) {
 825                         cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
 826                         break;
 827                 }
 828
 829                 if (rc > count) {
 830                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
 831                                  count);
 832                         break;
 833                 }
 834
 835                 iov_iter_advance(iter, rc);
 836                 count -= rc;
 837                 rc += start;
 838                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
 839
 840                 if (npages + cur_npages > max_pages) {
 841                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
 842                                  npages + cur_npages, max_pages);
 843                         break;
 844                 }
 845
 846                 for (i = 0; i < cur_npages; i++) {
 847                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
 848                         bv[npages + i].bv_page = pages[i];
 849                         bv[npages + i].bv_offset = start;
 850                         bv[npages + i].bv_len = len - start;
 851                         rc -= len;
 852                         start = 0;
 853                 }
 854
 855                 npages += cur_npages;
 856         }
 857
 858         kvfree(pages);
 859         ctx->bv = bv;
 860         ctx->len = saved_len - count;
 861         ctx->npages = npages;
 862         iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
 863         return 0;
 864 }
 865
 866 /**
 867  * cifs_alloc_hash - allocate hash and hash context together
 868  *
 869  * The caller has to make sure @sdesc is initialized to either NULL or
 870  * a valid context. Both can be freed via cifs_free_hash().
 871  */
 872 int
 873 cifs_alloc_hash(const char *name,
 874                 struct crypto_shash **shash, struct sdesc **sdesc)
 875 {
 876         int rc = 0;
 877         size_t size;
 878
 879         if (*sdesc != NULL)
 880                 return 0;
 881
 882         *shash = crypto_alloc_shash(name, 0, 0);
 883         if (IS_ERR(*shash)) {
 884                 cifs_dbg(VFS, "could not allocate crypto %s\n", name);
 885                 rc = PTR_ERR(*shash);
 886                 *shash = NULL;
 887                 *sdesc = NULL;
 888                 return rc;
 889         }
 890
 891         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
 892         *sdesc = kmalloc(size, GFP_KERNEL);
 893         if (*sdesc == NULL) {
 894                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
 895                 crypto_free_shash(*shash);
 896                 *shash = NULL;
 897                 return -ENOMEM;
 898         }
 899
 900         (*sdesc)->shash.tfm = *shash;
 901         (*sdesc)->shash.flags = 0x0;
 902         return 0;
 903 }
 904
 905 /**
 906  * cifs_free_hash - free hash and hash context together
 907  *
 908  * Freeing a NULL hash or context is safe.
 909  */
 910 void
 911 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
 912 {
 913         kfree(*sdesc);
 914         *sdesc = NULL;
 915         if (*shash)
 916                 crypto_free_shash(*shash);
 917         *shash = NULL;
 918 }
 919
 920 /**
 921  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
 922  * Input: rqst - a smb_rqst, page - a page index for rqst
 923  * Output: *len - the length for this page, *offset - the offset for this page
 924  */
 925 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
 926                                 unsigned int *len, unsigned int *offset)
 927 {
 928         *len = rqst->rq_pagesz;
 929         *offset = (page == 0) ? rqst->rq_offset : 0;
 930
 931         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
 932                 *len = rqst->rq_tailsz;
 933         else if (page == 0)
 934                 *len = rqst->rq_pagesz - rqst->rq_offset;
 935 }