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 ([email protected])
   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         }
 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         kzfree(buf_to_free->password);
 140         kfree(buf_to_free->crfid.fid);
 141         kfree(buf_to_free);
 142 }
 143
 144 struct smb_hdr *
 145 cifs_buf_get(void)
 146 {
 147         struct smb_hdr *ret_buf = NULL;
 148         /*
 149          * SMB2 header is bigger than CIFS one - no problems to clean some
 150          * more bytes for CIFS.
 151          */
 152         size_t buf_size = sizeof(struct smb2_sync_hdr);
 153
 154         /*
 155          * We could use negotiated size instead of max_msgsize -
 156          * but it may be more efficient to always alloc same size
 157          * albeit slightly larger than necessary and maxbuffersize
 158          * defaults to this and can not be bigger.
 159          */
 160         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 161
 162         /* clear the first few header bytes */
 163         /* for most paths, more is cleared in header_assemble */
 164         memset(ret_buf, 0, buf_size + 3);
 165         atomic_inc(&bufAllocCount);
 166 #ifdef CONFIG_CIFS_STATS2
 167         atomic_inc(&totBufAllocCount);
 168 #endif /* CONFIG_CIFS_STATS2 */
 169
 170         return ret_buf;
 171 }
 172
 173 void
 174 cifs_buf_release(void *buf_to_free)
 175 {
 176         if (buf_to_free == NULL) {
 177                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 178                 return;
 179         }
 180         mempool_free(buf_to_free, cifs_req_poolp);
 181
 182         atomic_dec(&bufAllocCount);
 183         return;
 184 }
 185
 186 struct smb_hdr *
 187 cifs_small_buf_get(void)
 188 {
 189         struct smb_hdr *ret_buf = NULL;
 190
 191 /* We could use negotiated size instead of max_msgsize -
 192    but it may be more efficient to always alloc same size
 193    albeit slightly larger than necessary and maxbuffersize
 194    defaults to this and can not be bigger */
 195         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 196         /* No need to clear memory here, cleared in header assemble */
 197         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 198         atomic_inc(&smBufAllocCount);
 199 #ifdef CONFIG_CIFS_STATS2
 200         atomic_inc(&totSmBufAllocCount);
 201 #endif /* CONFIG_CIFS_STATS2 */
 202
 203         return ret_buf;
 204 }
 205
 206 void
 207 cifs_small_buf_release(void *buf_to_free)
 208 {
 209
 210         if (buf_to_free == NULL) {
 211                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 212                 return;
 213         }
 214         mempool_free(buf_to_free, cifs_sm_req_poolp);
 215
 216         atomic_dec(&smBufAllocCount);
 217         return;
 218 }
 219
 220 void
 221 free_rsp_buf(int resp_buftype, void *rsp)
 222 {
 223         if (resp_buftype == CIFS_SMALL_BUFFER)
 224                 cifs_small_buf_release(rsp);
 225         else if (resp_buftype == CIFS_LARGE_BUFFER)
 226                 cifs_buf_release(rsp);
 227 }
 228
 229 /* NB: MID can not be set if treeCon not passed in, in that
 230    case it is responsbility of caller to set the mid */
 231 void
 232 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 233                 const struct cifs_tcon *treeCon, int word_count
 234                 /* length of fixed section (word count) in two byte units  */)
 235 {
 236         char *temp = (char *) buffer;
 237
 238         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 239
 240         buffer->smb_buf_length = cpu_to_be32(
 241             (2 * word_count) + sizeof(struct smb_hdr) -
 242             4 /*  RFC 1001 length field does not count */  +
 243             2 /* for bcc field itself */) ;
 244
 245         buffer->Protocol[0] = 0xFF;
 246         buffer->Protocol[1] = 'S';
 247         buffer->Protocol[2] = 'M';
 248         buffer->Protocol[3] = 'B';
 249         buffer->Command = smb_command;
 250         buffer->Flags = 0x00;   /* case sensitive */
 251         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 252         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 253         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 254         if (treeCon) {
 255                 buffer->Tid = treeCon->tid;
 256                 if (treeCon->ses) {
 257                         if (treeCon->ses->capabilities & CAP_UNICODE)
 258                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 259                         if (treeCon->ses->capabilities & CAP_STATUS32)
 260                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 261
 262                         /* Uid is not converted */
 263                         buffer->Uid = treeCon->ses->Suid;
 264                         buffer->Mid = get_next_mid(treeCon->ses->server);
 265                 }
 266                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 267                         buffer->Flags2 |= SMBFLG2_DFS;
 268                 if (treeCon->nocase)
 269                         buffer->Flags  |= SMBFLG_CASELESS;
 270                 if ((treeCon->ses) && (treeCon->ses->server))
 271                         if (treeCon->ses->server->sign)
 272                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 273         }
 274
 275 /*  endian conversion of flags is now done just before sending */
 276         buffer->WordCount = (char) word_count;
 277         return;
 278 }
 279
 280 static int
 281 check_smb_hdr(struct smb_hdr *smb)
 282 {
 283         /* does it have the right SMB "signature" ? */
 284         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 285                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 286                          *(unsigned int *)smb->Protocol);
 287                 return 1;
 288         }
 289
 290         /* if it's a response then accept */
 291         if (smb->Flags & SMBFLG_RESPONSE)
 292                 return 0;
 293
 294         /* only one valid case where server sends us request */
 295         if (smb->Command == SMB_COM_LOCKING_ANDX)
 296                 return 0;
 297
 298         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 299                  get_mid(smb));
 300         return 1;
 301 }
 302
 303 int
 304 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 305 {
 306         struct smb_hdr *smb = (struct smb_hdr *)buf;
 307         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 308         __u32 clc_len;  /* calculated length */
 309         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 310                  total_read, rfclen);
 311
 312         /* is this frame too small to even get to a BCC? */
 313         if (total_read < 2 + sizeof(struct smb_hdr)) {
 314                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 315                             && (smb->Status.CifsError != 0)) {
 316                         /* it's an error return */
 317                         smb->WordCount = 0;
 318                         /* some error cases do not return wct and bcc */
 319                         return 0;
 320                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 321                                 (smb->WordCount == 0)) {
 322                         char *tmp = (char *)smb;
 323                         /* Need to work around a bug in two servers here */
 324                         /* First, check if the part of bcc they sent was zero */
 325                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 326                                 /* some servers return only half of bcc
 327                                  * on simple responses (wct, bcc both zero)
 328                                  * in particular have seen this on
 329                                  * ulogoffX and FindClose. This leaves
 330                                  * one byte of bcc potentially unitialized
 331                                  */
 332                                 /* zero rest of bcc */
 333                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 334                                 return 0;
 335                         }
 336                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 337                 } else {
 338                         cifs_dbg(VFS, "Length less than smb header size\n");
 339                 }
 340                 return -EIO;
 341         }
 342
 343         /* otherwise, there is enough to get to the BCC */
 344         if (check_smb_hdr(smb))
 345                 return -EIO;
 346         clc_len = smbCalcSize(smb, server);
 347
 348         if (4 + rfclen != total_read) {
 349                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 350                          rfclen);
 351                 return -EIO;
 352         }
 353
 354         if (4 + rfclen != clc_len) {
 355                 __u16 mid = get_mid(smb);
 356                 /* check if bcc wrapped around for large read responses */
 357                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 358                         /* check if lengths match mod 64K */
 359                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 360                                 return 0; /* bcc wrapped */
 361                 }
 362                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 363                          clc_len, 4 + rfclen, mid);
 364
 365                 if (4 + rfclen < clc_len) {
 366                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 367                                  rfclen, mid);
 368                         return -EIO;
 369                 } else if (rfclen > clc_len + 512) {
 370                         /*
 371                          * Some servers (Windows XP in particular) send more
 372                          * data than the lengths in the SMB packet would
 373                          * indicate on certain calls (byte range locks and
 374                          * trans2 find first calls in particular). While the
 375                          * client can handle such a frame by ignoring the
 376                          * trailing data, we choose limit the amount of extra
 377                          * data to 512 bytes.
 378                          */
 379                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 380                                  rfclen, mid);
 381                         return -EIO;
 382                 }
 383         }
 384         return 0;
 385 }
 386
 387 bool
 388 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 389 {
 390         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 391         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 392         struct list_head *tmp, *tmp1, *tmp2;
 393         struct cifs_ses *ses;
 394         struct cifs_tcon *tcon;
 395         struct cifsInodeInfo *pCifsInode;
 396         struct cifsFileInfo *netfile;
 397
 398         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 399         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 400            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 401                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 402                         (struct smb_com_transaction_change_notify_rsp *)buf;
 403                 struct file_notify_information *pnotify;
 404                 __u32 data_offset = 0;
 405                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 406
 407                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 408                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 409
 410                         if (data_offset >
 411                             len - sizeof(struct file_notify_information)) {
 412                                 cifs_dbg(FYI, "invalid data_offset %u\n",
 413                                          data_offset);
 414                                 return true;
 415                         }
 416                         pnotify = (struct file_notify_information *)
 417                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 418                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 419                                  pnotify->FileName, pnotify->Action);
 420                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 421                                 sizeof(struct smb_hdr)+60); */
 422                         return true;
 423                 }
 424                 if (pSMBr->hdr.Status.CifsError) {
 425                         cifs_dbg(FYI, "notify err 0x%x\n",
 426                                  pSMBr->hdr.Status.CifsError);
 427                         return true;
 428                 }
 429                 return false;
 430         }
 431         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 432                 return false;
 433         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 434                 /* no sense logging error on invalid handle on oplock
 435                    break - harmless race between close request and oplock
 436                    break response is expected from time to time writing out
 437                    large dirty files cached on the client */
 438                 if ((NT_STATUS_INVALID_HANDLE) ==
 439                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 440                         cifs_dbg(FYI, "invalid handle on oplock break\n");
 441                         return true;
 442                 } else if (ERRbadfid ==
 443                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 444                         return true;
 445                 } else {
 446                         return false; /* on valid oplock brk we get "request" */
 447                 }
 448         }
 449         if (pSMB->hdr.WordCount != 8)
 450                 return false;
 451
 452         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 453                  pSMB->LockType, pSMB->OplockLevel);
 454         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 455                 return false;
 456
 457         /* look up tcon based on tid & uid */
 458         spin_lock(&cifs_tcp_ses_lock);
 459         list_for_each(tmp, &srv->smb_ses_list) {
 460                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 461                 list_for_each(tmp1, &ses->tcon_list) {
 462                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 463                         if (tcon->tid != buf->Tid)
 464                                 continue;
 465
 466                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 467                         spin_lock(&tcon->open_file_lock);
 468                         list_for_each(tmp2, &tcon->openFileList) {
 469                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 470                                                      tlist);
 471                                 if (pSMB->Fid != netfile->fid.netfid)
 472                                         continue;
 473
 474                                 cifs_dbg(FYI, "file id match, oplock break\n");
 475                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 476
 477                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 478                                         &pCifsInode->flags);
 479
 480                                 /*
 481                                  * Set flag if the server downgrades the oplock
 482                                  * to L2 else clear.
 483                                  */
 484                                 if (pSMB->OplockLevel)
 485                                         set_bit(
 486                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 487                                            &pCifsInode->flags);
 488                                 else
 489                                         clear_bit(
 490                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 491                                            &pCifsInode->flags);
 492
 493                                 queue_work(cifsoplockd_wq,
 494                                            &netfile->oplock_break);
 495                                 netfile->oplock_break_cancelled = false;
 496
 497                                 spin_unlock(&tcon->open_file_lock);
 498                                 spin_unlock(&cifs_tcp_ses_lock);
 499                                 return true;
 500                         }
 501                         spin_unlock(&tcon->open_file_lock);
 502                         spin_unlock(&cifs_tcp_ses_lock);
 503                         cifs_dbg(FYI, "No matching file for oplock break\n");
 504                         return true;
 505                 }
 506         }
 507         spin_unlock(&cifs_tcp_ses_lock);
 508         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 509         return true;
 510 }
 511
 512 void
 513 dump_smb(void *buf, int smb_buf_length)
 514 {
 515         if (traceSMB == 0)
 516                 return;
 517
 518         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 519                        smb_buf_length, true);
 520 }
 521
 522 void
 523 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 524 {
 525         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 526                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 527                 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",
 528                          cifs_sb_master_tcon(cifs_sb)->treeName);
 529         }
 530 }
 531
 532 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 533 {
 534         oplock &= 0xF;
 535
 536         if (oplock == OPLOCK_EXCLUSIVE) {
 537                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 538                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 539                          &cinode->vfs_inode);
 540         } else if (oplock == OPLOCK_READ) {
 541                 cinode->oplock = CIFS_CACHE_READ_FLG;
 542                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 543                          &cinode->vfs_inode);
 544         } else
 545                 cinode->oplock = 0;
 546 }
 547
 548 /*
 549  * We wait for oplock breaks to be processed before we attempt to perform
 550  * writes.
 551  */
 552 int cifs_get_writer(struct cifsInodeInfo *cinode)
 553 {
 554         int rc;
 555
 556 start:
 557         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 558                          TASK_KILLABLE);
 559         if (rc)
 560                 return rc;
 561
 562         spin_lock(&cinode->writers_lock);
 563         if (!cinode->writers)
 564                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 565         cinode->writers++;
 566         /* Check to see if we have started servicing an oplock break */
 567         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 568                 cinode->writers--;
 569                 if (cinode->writers == 0) {
 570                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 571                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 572                 }
 573                 spin_unlock(&cinode->writers_lock);
 574                 goto start;
 575         }
 576         spin_unlock(&cinode->writers_lock);
 577         return 0;
 578 }
 579
 580 void cifs_put_writer(struct cifsInodeInfo *cinode)
 581 {
 582         spin_lock(&cinode->writers_lock);
 583         cinode->writers--;
 584         if (cinode->writers == 0) {
 585                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 586                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 587         }
 588         spin_unlock(&cinode->writers_lock);
 589 }
 590
 591 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 592 {
 593         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 594         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 595 }
 596
 597 bool
 598 backup_cred(struct cifs_sb_info *cifs_sb)
 599 {
 600         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 601                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 602                         return true;
 603         }
 604         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 605                 if (in_group_p(cifs_sb->mnt_backupgid))
 606                         return true;
 607         }
 608
 609         return false;
 610 }
 611
 612 void
 613 cifs_del_pending_open(struct cifs_pending_open *open)
 614 {
 615         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 616         list_del(&open->olist);
 617         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 618 }
 619
 620 void
 621 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 622                              struct cifs_pending_open *open)
 623 {
 624         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 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 }
 744
 745 struct cifs_aio_ctx *
 746 cifs_aio_ctx_alloc(void)
 747 {
 748         struct cifs_aio_ctx *ctx;
 749
 750         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 751         if (!ctx)
 752                 return NULL;
 753
 754         INIT_LIST_HEAD(&ctx->list);
 755         mutex_init(&ctx->aio_mutex);
 756         init_completion(&ctx->done);
 757         kref_init(&ctx->refcount);
 758         return ctx;
 759 }
 760
 761 void
 762 cifs_aio_ctx_release(struct kref *refcount)
 763 {
 764         struct cifs_aio_ctx *ctx = container_of(refcount,
 765                                         struct cifs_aio_ctx, refcount);
 766
 767         cifsFileInfo_put(ctx->cfile);
 768         kvfree(ctx->bv);
 769         kfree(ctx);
 770 }
 771
 772 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
 773
 774 int
 775 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 776 {
 777         ssize_t rc;
 778         unsigned int cur_npages;
 779         unsigned int npages = 0;
 780         unsigned int i;
 781         size_t len;
 782         size_t count = iov_iter_count(iter);
 783         unsigned int saved_len;
 784         size_t start;
 785         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
 786         struct page **pages = NULL;
 787         struct bio_vec *bv = NULL;
 788
 789         if (iter->type & ITER_KVEC) {
 790                 memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
 791                 ctx->len = count;
 792                 iov_iter_advance(iter, count);
 793                 return 0;
 794         }
 795
 796         if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
 797                 bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
 798                                    GFP_KERNEL);
 799
 800         if (!bv) {
 801                 bv = vmalloc(array_size(max_pages, sizeof(struct bio_vec)));
 802                 if (!bv)
 803                         return -ENOMEM;
 804         }
 805
 806         if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
 807                 pages = kmalloc_array(max_pages, sizeof(struct page *),
 808                                       GFP_KERNEL);
 809
 810         if (!pages) {
 811                 pages = vmalloc(array_size(max_pages, sizeof(struct page *)));
 812                 if (!pages) {
 813                         kvfree(bv);
 814                         return -ENOMEM;
 815                 }
 816         }
 817
 818         saved_len = count;
 819
 820         while (count && npages < max_pages) {
 821                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
 822                 if (rc < 0) {
 823                         cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
 824                         break;
 825                 }
 826
 827                 if (rc > count) {
 828                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
 829                                  count);
 830                         break;
 831                 }
 832
 833                 iov_iter_advance(iter, rc);
 834                 count -= rc;
 835                 rc += start;
 836                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
 837
 838                 if (npages + cur_npages > max_pages) {
 839                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
 840                                  npages + cur_npages, max_pages);
 841                         break;
 842                 }
 843
 844                 for (i = 0; i < cur_npages; i++) {
 845                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
 846                         bv[npages + i].bv_page = pages[i];
 847                         bv[npages + i].bv_offset = start;
 848                         bv[npages + i].bv_len = len - start;
 849                         rc -= len;
 850                         start = 0;
 851                 }
 852
 853                 npages += cur_npages;
 854         }
 855
 856         kvfree(pages);
 857         ctx->bv = bv;
 858         ctx->len = saved_len - count;
 859         ctx->npages = npages;
 860         iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
 861         return 0;
 862 }
 863
 864 /**
 865  * cifs_alloc_hash - allocate hash and hash context together
 866  *
 867  * The caller has to make sure @sdesc is initialized to either NULL or
 868  * a valid context. Both can be freed via cifs_free_hash().
 869  */
 870 int
 871 cifs_alloc_hash(const char *name,
 872                 struct crypto_shash **shash, struct sdesc **sdesc)
 873 {
 874         int rc = 0;
 875         size_t size;
 876
 877         if (*sdesc != NULL)
 878                 return 0;
 879
 880         *shash = crypto_alloc_shash(name, 0, 0);
 881         if (IS_ERR(*shash)) {
 882                 cifs_dbg(VFS, "could not allocate crypto %s\n", name);
 883                 rc = PTR_ERR(*shash);
 884                 *shash = NULL;
 885                 *sdesc = NULL;
 886                 return rc;
 887         }
 888
 889         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
 890         *sdesc = kmalloc(size, GFP_KERNEL);
 891         if (*sdesc == NULL) {
 892                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
 893                 crypto_free_shash(*shash);
 894                 *shash = NULL;
 895                 return -ENOMEM;
 896         }
 897
 898         (*sdesc)->shash.tfm = *shash;
 899         (*sdesc)->shash.flags = 0x0;
 900         return 0;
 901 }
 902
 903 /**
 904  * cifs_free_hash - free hash and hash context together
 905  *
 906  * Freeing a NULL hash or context is safe.
 907  */
 908 void
 909 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
 910 {
 911         kfree(*sdesc);
 912         *sdesc = NULL;
 913         if (*shash)
 914                 crypto_free_shash(*shash);
 915         *shash = NULL;
 916 }
 917
 918 /**
 919  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
 920  * Input: rqst - a smb_rqst, page - a page index for rqst
 921  * Output: *len - the length for this page, *offset - the offset for this page
 922  */
 923 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
 924                                 unsigned int *len, unsigned int *offset)
 925 {
 926         *len = rqst->rq_pagesz;
 927         *offset = (page == 0) ? rqst->rq_offset : 0;
 928
 929         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
 930                 *len = rqst->rq_tailsz;
 931         else if (page == 0)
 932                 *len = rqst->rq_pagesz - rqst->rq_offset;
 933 }