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
 115         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 116         if (!ret_buf)
 117                 return NULL;
 118         ret_buf->crfid.fid = kzalloc(sizeof(*ret_buf->crfid.fid), GFP_KERNEL);
 119         if (!ret_buf->crfid.fid) {
 120                 kfree(ret_buf);
 121                 return NULL;
 122         }
 123
 124         atomic_inc(&tconInfoAllocCount);
 125         ret_buf->tidStatus = CifsNew;
 126         ++ret_buf->tc_count;
 127         INIT_LIST_HEAD(&ret_buf->openFileList);
 128         INIT_LIST_HEAD(&ret_buf->tcon_list);
 129         spin_lock_init(&ret_buf->open_file_lock);
 130         mutex_init(&ret_buf->crfid.fid_mutex);
 131         spin_lock_init(&ret_buf->stat_lock);
 132         atomic_set(&ret_buf->num_local_opens, 0);
 133         atomic_set(&ret_buf->num_remote_opens, 0);
 134
 135         return ret_buf;
 136 }
 137
 138 void
 139 tconInfoFree(struct cifs_tcon *buf_to_free)
 140 {
 141         if (buf_to_free == NULL) {
 142                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 143                 return;
 144         }
 145         atomic_dec(&tconInfoAllocCount);
 146         kfree(buf_to_free->nativeFileSystem);
 147         kzfree(buf_to_free->password);
 148         kfree(buf_to_free->crfid.fid);
 149 #ifdef CONFIG_CIFS_DFS_UPCALL
 150         kfree(buf_to_free->dfs_path);
 151 #endif
 152         kfree(buf_to_free);
 153 }
 154
 155 struct smb_hdr *
 156 cifs_buf_get(void)
 157 {
 158         struct smb_hdr *ret_buf = NULL;
 159         /*
 160          * SMB2 header is bigger than CIFS one - no problems to clean some
 161          * more bytes for CIFS.
 162          */
 163         size_t buf_size = sizeof(struct smb2_sync_hdr);
 164
 165         /*
 166          * We could use negotiated size instead of max_msgsize -
 167          * but it may be more efficient to always alloc same size
 168          * albeit slightly larger than necessary and maxbuffersize
 169          * defaults to this and can not be bigger.
 170          */
 171         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 172
 173         /* clear the first few header bytes */
 174         /* for most paths, more is cleared in header_assemble */
 175         memset(ret_buf, 0, buf_size + 3);
 176         atomic_inc(&bufAllocCount);
 177 #ifdef CONFIG_CIFS_STATS2
 178         atomic_inc(&totBufAllocCount);
 179 #endif /* CONFIG_CIFS_STATS2 */
 180
 181         return ret_buf;
 182 }
 183
 184 void
 185 cifs_buf_release(void *buf_to_free)
 186 {
 187         if (buf_to_free == NULL) {
 188                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 189                 return;
 190         }
 191         mempool_free(buf_to_free, cifs_req_poolp);
 192
 193         atomic_dec(&bufAllocCount);
 194         return;
 195 }
 196
 197 struct smb_hdr *
 198 cifs_small_buf_get(void)
 199 {
 200         struct smb_hdr *ret_buf = NULL;
 201
 202 /* We could use negotiated size instead of max_msgsize -
 203    but it may be more efficient to always alloc same size
 204    albeit slightly larger than necessary and maxbuffersize
 205    defaults to this and can not be bigger */
 206         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 207         /* No need to clear memory here, cleared in header assemble */
 208         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 209         atomic_inc(&smBufAllocCount);
 210 #ifdef CONFIG_CIFS_STATS2
 211         atomic_inc(&totSmBufAllocCount);
 212 #endif /* CONFIG_CIFS_STATS2 */
 213
 214         return ret_buf;
 215 }
 216
 217 void
 218 cifs_small_buf_release(void *buf_to_free)
 219 {
 220
 221         if (buf_to_free == NULL) {
 222                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 223                 return;
 224         }
 225         mempool_free(buf_to_free, cifs_sm_req_poolp);
 226
 227         atomic_dec(&smBufAllocCount);
 228         return;
 229 }
 230
 231 void
 232 free_rsp_buf(int resp_buftype, void *rsp)
 233 {
 234         if (resp_buftype == CIFS_SMALL_BUFFER)
 235                 cifs_small_buf_release(rsp);
 236         else if (resp_buftype == CIFS_LARGE_BUFFER)
 237                 cifs_buf_release(rsp);
 238 }
 239
 240 /* NB: MID can not be set if treeCon not passed in, in that
 241    case it is responsbility of caller to set the mid */
 242 void
 243 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 244                 const struct cifs_tcon *treeCon, int word_count
 245                 /* length of fixed section (word count) in two byte units  */)
 246 {
 247         char *temp = (char *) buffer;
 248
 249         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 250
 251         buffer->smb_buf_length = cpu_to_be32(
 252             (2 * word_count) + sizeof(struct smb_hdr) -
 253             4 /*  RFC 1001 length field does not count */  +
 254             2 /* for bcc field itself */) ;
 255
 256         buffer->Protocol[0] = 0xFF;
 257         buffer->Protocol[1] = 'S';
 258         buffer->Protocol[2] = 'M';
 259         buffer->Protocol[3] = 'B';
 260         buffer->Command = smb_command;
 261         buffer->Flags = 0x00;   /* case sensitive */
 262         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 263         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 264         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 265         if (treeCon) {
 266                 buffer->Tid = treeCon->tid;
 267                 if (treeCon->ses) {
 268                         if (treeCon->ses->capabilities & CAP_UNICODE)
 269                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 270                         if (treeCon->ses->capabilities & CAP_STATUS32)
 271                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 272
 273                         /* Uid is not converted */
 274                         buffer->Uid = treeCon->ses->Suid;
 275                         buffer->Mid = get_next_mid(treeCon->ses->server);
 276                 }
 277                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 278                         buffer->Flags2 |= SMBFLG2_DFS;
 279                 if (treeCon->nocase)
 280                         buffer->Flags  |= SMBFLG_CASELESS;
 281                 if ((treeCon->ses) && (treeCon->ses->server))
 282                         if (treeCon->ses->server->sign)
 283                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 284         }
 285
 286 /*  endian conversion of flags is now done just before sending */
 287         buffer->WordCount = (char) word_count;
 288         return;
 289 }
 290
 291 static int
 292 check_smb_hdr(struct smb_hdr *smb)
 293 {
 294         /* does it have the right SMB "signature" ? */
 295         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 296                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 297                          *(unsigned int *)smb->Protocol);
 298                 return 1;
 299         }
 300
 301         /* if it's a response then accept */
 302         if (smb->Flags & SMBFLG_RESPONSE)
 303                 return 0;
 304
 305         /* only one valid case where server sends us request */
 306         if (smb->Command == SMB_COM_LOCKING_ANDX)
 307                 return 0;
 308
 309         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 310                  get_mid(smb));
 311         return 1;
 312 }
 313
 314 int
 315 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 316 {
 317         struct smb_hdr *smb = (struct smb_hdr *)buf;
 318         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 319         __u32 clc_len;  /* calculated length */
 320         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 321                  total_read, rfclen);
 322
 323         /* is this frame too small to even get to a BCC? */
 324         if (total_read < 2 + sizeof(struct smb_hdr)) {
 325                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 326                             && (smb->Status.CifsError != 0)) {
 327                         /* it's an error return */
 328                         smb->WordCount = 0;
 329                         /* some error cases do not return wct and bcc */
 330                         return 0;
 331                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 332                                 (smb->WordCount == 0)) {
 333                         char *tmp = (char *)smb;
 334                         /* Need to work around a bug in two servers here */
 335                         /* First, check if the part of bcc they sent was zero */
 336                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 337                                 /* some servers return only half of bcc
 338                                  * on simple responses (wct, bcc both zero)
 339                                  * in particular have seen this on
 340                                  * ulogoffX and FindClose. This leaves
 341                                  * one byte of bcc potentially unitialized
 342                                  */
 343                                 /* zero rest of bcc */
 344                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 345                                 return 0;
 346                         }
 347                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 348                 } else {
 349                         cifs_dbg(VFS, "Length less than smb header size\n");
 350                 }
 351                 return -EIO;
 352         }
 353
 354         /* otherwise, there is enough to get to the BCC */
 355         if (check_smb_hdr(smb))
 356                 return -EIO;
 357         clc_len = smbCalcSize(smb, server);
 358
 359         if (4 + rfclen != total_read) {
 360                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 361                          rfclen);
 362                 return -EIO;
 363         }
 364
 365         if (4 + rfclen != clc_len) {
 366                 __u16 mid = get_mid(smb);
 367                 /* check if bcc wrapped around for large read responses */
 368                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 369                         /* check if lengths match mod 64K */
 370                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 371                                 return 0; /* bcc wrapped */
 372                 }
 373                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 374                          clc_len, 4 + rfclen, mid);
 375
 376                 if (4 + rfclen < clc_len) {
 377                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 378                                  rfclen, mid);
 379                         return -EIO;
 380                 } else if (rfclen > clc_len + 512) {
 381                         /*
 382                          * Some servers (Windows XP in particular) send more
 383                          * data than the lengths in the SMB packet would
 384                          * indicate on certain calls (byte range locks and
 385                          * trans2 find first calls in particular). While the
 386                          * client can handle such a frame by ignoring the
 387                          * trailing data, we choose limit the amount of extra
 388                          * data to 512 bytes.
 389                          */
 390                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 391                                  rfclen, mid);
 392                         return -EIO;
 393                 }
 394         }
 395         return 0;
 396 }
 397
 398 bool
 399 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 400 {
 401         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 402         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 403         struct list_head *tmp, *tmp1, *tmp2;
 404         struct cifs_ses *ses;
 405         struct cifs_tcon *tcon;
 406         struct cifsInodeInfo *pCifsInode;
 407         struct cifsFileInfo *netfile;
 408
 409         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 410         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 411            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 412                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 413                         (struct smb_com_transaction_change_notify_rsp *)buf;
 414                 struct file_notify_information *pnotify;
 415                 __u32 data_offset = 0;
 416                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 417
 418                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 419                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 420
 421                         if (data_offset >
 422                             len - sizeof(struct file_notify_information)) {
 423                                 cifs_dbg(FYI, "invalid data_offset %u\n",
 424                                          data_offset);
 425                                 return true;
 426                         }
 427                         pnotify = (struct file_notify_information *)
 428                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 429                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 430                                  pnotify->FileName, pnotify->Action);
 431                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 432                                 sizeof(struct smb_hdr)+60); */
 433                         return true;
 434                 }
 435                 if (pSMBr->hdr.Status.CifsError) {
 436                         cifs_dbg(FYI, "notify err 0x%x\n",
 437                                  pSMBr->hdr.Status.CifsError);
 438                         return true;
 439                 }
 440                 return false;
 441         }
 442         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 443                 return false;
 444         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 445                 /* no sense logging error on invalid handle on oplock
 446                    break - harmless race between close request and oplock
 447                    break response is expected from time to time writing out
 448                    large dirty files cached on the client */
 449                 if ((NT_STATUS_INVALID_HANDLE) ==
 450                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 451                         cifs_dbg(FYI, "invalid handle on oplock break\n");
 452                         return true;
 453                 } else if (ERRbadfid ==
 454                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 455                         return true;
 456                 } else {
 457                         return false; /* on valid oplock brk we get "request" */
 458                 }
 459         }
 460         if (pSMB->hdr.WordCount != 8)
 461                 return false;
 462
 463         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 464                  pSMB->LockType, pSMB->OplockLevel);
 465         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 466                 return false;
 467
 468         /* look up tcon based on tid & uid */
 469         spin_lock(&cifs_tcp_ses_lock);
 470         list_for_each(tmp, &srv->smb_ses_list) {
 471                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 472                 list_for_each(tmp1, &ses->tcon_list) {
 473                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 474                         if (tcon->tid != buf->Tid)
 475                                 continue;
 476
 477                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 478                         spin_lock(&tcon->open_file_lock);
 479                         list_for_each(tmp2, &tcon->openFileList) {
 480                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 481                                                      tlist);
 482                                 if (pSMB->Fid != netfile->fid.netfid)
 483                                         continue;
 484
 485                                 cifs_dbg(FYI, "file id match, oplock break\n");
 486                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 487
 488                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 489                                         &pCifsInode->flags);
 490
 491                                 /*
 492                                  * Set flag if the server downgrades the oplock
 493                                  * to L2 else clear.
 494                                  */
 495                                 if (pSMB->OplockLevel)
 496                                         set_bit(
 497                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 498                                            &pCifsInode->flags);
 499                                 else
 500                                         clear_bit(
 501                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 502                                            &pCifsInode->flags);
 503
 504                                 cifs_queue_oplock_break(netfile);
 505                                 netfile->oplock_break_cancelled = false;
 506
 507                                 spin_unlock(&tcon->open_file_lock);
 508                                 spin_unlock(&cifs_tcp_ses_lock);
 509                                 return true;
 510                         }
 511                         spin_unlock(&tcon->open_file_lock);
 512                         spin_unlock(&cifs_tcp_ses_lock);
 513                         cifs_dbg(FYI, "No matching file for oplock break\n");
 514                         return true;
 515                 }
 516         }
 517         spin_unlock(&cifs_tcp_ses_lock);
 518         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 519         return true;
 520 }
 521
 522 void
 523 dump_smb(void *buf, int smb_buf_length)
 524 {
 525         if (traceSMB == 0)
 526                 return;
 527
 528         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 529                        smb_buf_length, true);
 530 }
 531
 532 void
 533 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 534 {
 535         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 536                 struct cifs_tcon *tcon = NULL;
 537
 538                 if (cifs_sb->master_tlink)
 539                         tcon = cifs_sb_master_tcon(cifs_sb);
 540
 541                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 542                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 543                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s.\n",
 544                          tcon ? tcon->treeName : "new server");
 545                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS).\n");
 546                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 547
 548         }
 549 }
 550
 551 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 552 {
 553         oplock &= 0xF;
 554
 555         if (oplock == OPLOCK_EXCLUSIVE) {
 556                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 557                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 558                          &cinode->vfs_inode);
 559         } else if (oplock == OPLOCK_READ) {
 560                 cinode->oplock = CIFS_CACHE_READ_FLG;
 561                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 562                          &cinode->vfs_inode);
 563         } else
 564                 cinode->oplock = 0;
 565 }
 566
 567 /*
 568  * We wait for oplock breaks to be processed before we attempt to perform
 569  * writes.
 570  */
 571 int cifs_get_writer(struct cifsInodeInfo *cinode)
 572 {
 573         int rc;
 574
 575 start:
 576         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 577                          TASK_KILLABLE);
 578         if (rc)
 579                 return rc;
 580
 581         spin_lock(&cinode->writers_lock);
 582         if (!cinode->writers)
 583                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 584         cinode->writers++;
 585         /* Check to see if we have started servicing an oplock break */
 586         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 587                 cinode->writers--;
 588                 if (cinode->writers == 0) {
 589                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 590                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 591                 }
 592                 spin_unlock(&cinode->writers_lock);
 593                 goto start;
 594         }
 595         spin_unlock(&cinode->writers_lock);
 596         return 0;
 597 }
 598
 599 void cifs_put_writer(struct cifsInodeInfo *cinode)
 600 {
 601         spin_lock(&cinode->writers_lock);
 602         cinode->writers--;
 603         if (cinode->writers == 0) {
 604                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 605                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 606         }
 607         spin_unlock(&cinode->writers_lock);
 608 }
 609
 610 /**
 611  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 612  *
 613  * This function is called from the demultiplex thread when it
 614  * receives an oplock break for @cfile.
 615  *
 616  * Assumes the tcon->open_file_lock is held.
 617  * Assumes cfile->file_info_lock is NOT held.
 618  */
 619 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 620 {
 621         /*
 622          * Bump the handle refcount now while we hold the
 623          * open_file_lock to enforce the validity of it for the oplock
 624          * break handler. The matching put is done at the end of the
 625          * handler.
 626          */
 627         cifsFileInfo_get(cfile);
 628
 629         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 630 }
 631
 632 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 633 {
 634         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 635         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 636 }
 637
 638 bool
 639 backup_cred(struct cifs_sb_info *cifs_sb)
 640 {
 641         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 642                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 643                         return true;
 644         }
 645         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 646                 if (in_group_p(cifs_sb->mnt_backupgid))
 647                         return true;
 648         }
 649
 650         return false;
 651 }
 652
 653 void
 654 cifs_del_pending_open(struct cifs_pending_open *open)
 655 {
 656         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 657         list_del(&open->olist);
 658         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 659 }
 660
 661 void
 662 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 663                              struct cifs_pending_open *open)
 664 {
 665         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 666         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 667         open->tlink = tlink;
 668         fid->pending_open = open;
 669         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 670 }
 671
 672 void
 673 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 674                       struct cifs_pending_open *open)
 675 {
 676         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 677         cifs_add_pending_open_locked(fid, tlink, open);
 678         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 679 }
 680
 681 /* parses DFS refferal V3 structure
 682  * caller is responsible for freeing target_nodes
 683  * returns:
 684  * - on success - 0
 685  * - on failure - errno
 686  */
 687 int
 688 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 689                     unsigned int *num_of_nodes,
 690                     struct dfs_info3_param **target_nodes,
 691                     const struct nls_table *nls_codepage, int remap,
 692                     const char *searchName, bool is_unicode)
 693 {
 694         int i, rc = 0;
 695         char *data_end;
 696         struct dfs_referral_level_3 *ref;
 697
 698         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 699
 700         if (*num_of_nodes < 1) {
 701                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 702                          *num_of_nodes);
 703                 rc = -EINVAL;
 704                 goto parse_DFS_referrals_exit;
 705         }
 706
 707         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 708         if (ref->VersionNumber != cpu_to_le16(3)) {
 709                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 710                          le16_to_cpu(ref->VersionNumber));
 711                 rc = -EINVAL;
 712                 goto parse_DFS_referrals_exit;
 713         }
 714
 715         /* get the upper boundary of the resp buffer */
 716         data_end = (char *)rsp + rsp_size;
 717
 718         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 719                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 720
 721         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 722                                 GFP_KERNEL);
 723         if (*target_nodes == NULL) {
 724                 rc = -ENOMEM;
 725                 goto parse_DFS_referrals_exit;
 726         }
 727
 728         /* collect necessary data from referrals */
 729         for (i = 0; i < *num_of_nodes; i++) {
 730                 char *temp;
 731                 int max_len;
 732                 struct dfs_info3_param *node = (*target_nodes)+i;
 733
 734                 node->flags = le32_to_cpu(rsp->DFSFlags);
 735                 if (is_unicode) {
 736                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 737                                                 GFP_KERNEL);
 738                         if (tmp == NULL) {
 739                                 rc = -ENOMEM;
 740                                 goto parse_DFS_referrals_exit;
 741                         }
 742                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 743                                            PATH_MAX, nls_codepage, remap);
 744                         node->path_consumed = cifs_utf16_bytes(tmp,
 745                                         le16_to_cpu(rsp->PathConsumed),
 746                                         nls_codepage);
 747                         kfree(tmp);
 748                 } else
 749                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 750
 751                 node->server_type = le16_to_cpu(ref->ServerType);
 752                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 753
 754                 /* copy DfsPath */
 755                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 756                 max_len = data_end - temp;
 757                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 758                                                 is_unicode, nls_codepage);
 759                 if (!node->path_name) {
 760                         rc = -ENOMEM;
 761                         goto parse_DFS_referrals_exit;
 762                 }
 763
 764                 /* copy link target UNC */
 765                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 766                 max_len = data_end - temp;
 767                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 768                                                 is_unicode, nls_codepage);
 769                 if (!node->node_name) {
 770                         rc = -ENOMEM;
 771                         goto parse_DFS_referrals_exit;
 772                 }
 773
 774                 node->ttl = le32_to_cpu(ref->TimeToLive);
 775
 776                 ref++;
 777         }
 778
 779 parse_DFS_referrals_exit:
 780         if (rc) {
 781                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 782                 *target_nodes = NULL;
 783                 *num_of_nodes = 0;
 784         }
 785         return rc;
 786 }
 787
 788 struct cifs_aio_ctx *
 789 cifs_aio_ctx_alloc(void)
 790 {
 791         struct cifs_aio_ctx *ctx;
 792
 793         /*
 794          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
 795          * to false so that we know when we have to unreference pages within
 796          * cifs_aio_ctx_release()
 797          */
 798         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 799         if (!ctx)
 800                 return NULL;
 801
 802         INIT_LIST_HEAD(&ctx->list);
 803         mutex_init(&ctx->aio_mutex);
 804         init_completion(&ctx->done);
 805         kref_init(&ctx->refcount);
 806         return ctx;
 807 }
 808
 809 void
 810 cifs_aio_ctx_release(struct kref *refcount)
 811 {
 812         struct cifs_aio_ctx *ctx = container_of(refcount,
 813                                         struct cifs_aio_ctx, refcount);
 814
 815         cifsFileInfo_put(ctx->cfile);
 816
 817         /*
 818          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
 819          * which means that iov_iter_get_pages() was a success and thus that
 820          * we have taken reference on pages.
 821          */
 822         if (ctx->bv) {
 823                 unsigned i;
 824
 825                 for (i = 0; i < ctx->npages; i++) {
 826                         if (ctx->should_dirty)
 827                                 set_page_dirty(ctx->bv[i].bv_page);
 828                         put_page(ctx->bv[i].bv_page);
 829                 }
 830                 kvfree(ctx->bv);
 831         }
 832
 833         kfree(ctx);
 834 }
 835
 836 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
 837
 838 int
 839 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 840 {
 841         ssize_t rc;
 842         unsigned int cur_npages;
 843         unsigned int npages = 0;
 844         unsigned int i;
 845         size_t len;
 846         size_t count = iov_iter_count(iter);
 847         unsigned int saved_len;
 848         size_t start;
 849         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
 850         struct page **pages = NULL;
 851         struct bio_vec *bv = NULL;
 852
 853         if (iov_iter_is_kvec(iter)) {
 854                 memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
 855                 ctx->len = count;
 856                 iov_iter_advance(iter, count);
 857                 return 0;
 858         }
 859
 860         if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
 861                 bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
 862                                    GFP_KERNEL);
 863
 864         if (!bv) {
 865                 bv = vmalloc(array_size(max_pages, sizeof(struct bio_vec)));
 866                 if (!bv)
 867                         return -ENOMEM;
 868         }
 869
 870         if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
 871                 pages = kmalloc_array(max_pages, sizeof(struct page *),
 872                                       GFP_KERNEL);
 873
 874         if (!pages) {
 875                 pages = vmalloc(array_size(max_pages, sizeof(struct page *)));
 876                 if (!pages) {
 877                         kvfree(bv);
 878                         return -ENOMEM;
 879                 }
 880         }
 881
 882         saved_len = count;
 883
 884         while (count && npages < max_pages) {
 885                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
 886                 if (rc < 0) {
 887                         cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
 888                         break;
 889                 }
 890
 891                 if (rc > count) {
 892                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
 893                                  count);
 894                         break;
 895                 }
 896
 897                 iov_iter_advance(iter, rc);
 898                 count -= rc;
 899                 rc += start;
 900                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
 901
 902                 if (npages + cur_npages > max_pages) {
 903                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
 904                                  npages + cur_npages, max_pages);
 905                         break;
 906                 }
 907
 908                 for (i = 0; i < cur_npages; i++) {
 909                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
 910                         bv[npages + i].bv_page = pages[i];
 911                         bv[npages + i].bv_offset = start;
 912                         bv[npages + i].bv_len = len - start;
 913                         rc -= len;
 914                         start = 0;
 915                 }
 916
 917                 npages += cur_npages;
 918         }
 919
 920         kvfree(pages);
 921         ctx->bv = bv;
 922         ctx->len = saved_len - count;
 923         ctx->npages = npages;
 924         iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
 925         return 0;
 926 }
 927
 928 /**
 929  * cifs_alloc_hash - allocate hash and hash context together
 930  *
 931  * The caller has to make sure @sdesc is initialized to either NULL or
 932  * a valid context. Both can be freed via cifs_free_hash().
 933  */
 934 int
 935 cifs_alloc_hash(const char *name,
 936                 struct crypto_shash **shash, struct sdesc **sdesc)
 937 {
 938         int rc = 0;
 939         size_t size;
 940
 941         if (*sdesc != NULL)
 942                 return 0;
 943
 944         *shash = crypto_alloc_shash(name, 0, 0);
 945         if (IS_ERR(*shash)) {
 946                 cifs_dbg(VFS, "could not allocate crypto %s\n", name);
 947                 rc = PTR_ERR(*shash);
 948                 *shash = NULL;
 949                 *sdesc = NULL;
 950                 return rc;
 951         }
 952
 953         size = sizeof(struct shash_desc) + crypto_shash_descsize(*shash);
 954         *sdesc = kmalloc(size, GFP_KERNEL);
 955         if (*sdesc == NULL) {
 956                 cifs_dbg(VFS, "no memory left to allocate crypto %s\n", name);
 957                 crypto_free_shash(*shash);
 958                 *shash = NULL;
 959                 return -ENOMEM;
 960         }
 961
 962         (*sdesc)->shash.tfm = *shash;
 963         return 0;
 964 }
 965
 966 /**
 967  * cifs_free_hash - free hash and hash context together
 968  *
 969  * Freeing a NULL hash or context is safe.
 970  */
 971 void
 972 cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc)
 973 {
 974         kfree(*sdesc);
 975         *sdesc = NULL;
 976         if (*shash)
 977                 crypto_free_shash(*shash);
 978         *shash = NULL;
 979 }
 980
 981 /**
 982  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
 983  * Input: rqst - a smb_rqst, page - a page index for rqst
 984  * Output: *len - the length for this page, *offset - the offset for this page
 985  */
 986 void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,
 987                                 unsigned int *len, unsigned int *offset)
 988 {
 989         *len = rqst->rq_pagesz;
 990         *offset = (page == 0) ? rqst->rq_offset : 0;
 991
 992         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
 993                 *len = rqst->rq_tailsz;
 994         else if (page == 0)
 995                 *len = rqst->rq_pagesz - rqst->rq_offset;
 996 }
 997
 998 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
 999 {
1000         const char *end;
1001
1002         /* skip initial slashes */
1003         while (*unc && (*unc == '\\' || *unc == '/'))
1004                 unc++;
1005
1006         end = unc;
1007
1008         while (*end && !(*end == '\\' || *end == '/'))
1009                 end++;
1010
1011         *h = unc;
1012         *len = end - unc;
1013 }
1014
1015 /**
1016  * copy_path_name - copy src path to dst, possibly truncating
1017  *
1018  * returns number of bytes written (including trailing nul)
1019  */
1020 int copy_path_name(char *dst, const char *src)
1021 {
1022         int name_len;
1023
1024         /*
1025          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1026          * will truncate and strlen(dst) will be PATH_MAX-1
1027          */
1028         name_len = strscpy(dst, src, PATH_MAX);
1029         if (WARN_ON_ONCE(name_len < 0))
1030                 name_len = PATH_MAX-1;
1031
1032         /* we count the trailing nul */
1033         name_len++;
1034         return name_len;
1035 }