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 #ifdef CONFIG_CIFS_SMB2
  34 #include "smb2pdu.h"
  35 #endif
  36
  37 extern mempool_t *cifs_sm_req_poolp;
  38 extern mempool_t *cifs_req_poolp;
  39
  40 /* The xid serves as a useful identifier for each incoming vfs request,
  41    in a similar way to the mid which is useful to track each sent smb,
  42    and CurrentXid can also provide a running counter (although it
  43    will eventually wrap past zero) of the total vfs operations handled
  44    since the cifs fs was mounted */
  45
  46 unsigned int
  47 _get_xid(void)
  48 {
  49         unsigned int xid;
  50
  51         spin_lock(&GlobalMid_Lock);
  52         GlobalTotalActiveXid++;
  53
  54         /* keep high water mark for number of simultaneous ops in filesystem */
  55         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  56                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  57         if (GlobalTotalActiveXid > 65000)
  58                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  59         xid = GlobalCurrentXid++;
  60         spin_unlock(&GlobalMid_Lock);
  61         return xid;
  62 }
  63
  64 void
  65 _free_xid(unsigned int xid)
  66 {
  67         spin_lock(&GlobalMid_Lock);
  68         /* if (GlobalTotalActiveXid == 0)
  69                 BUG(); */
  70         GlobalTotalActiveXid--;
  71         spin_unlock(&GlobalMid_Lock);
  72 }
  73
  74 struct cifs_ses *
  75 sesInfoAlloc(void)
  76 {
  77         struct cifs_ses *ret_buf;
  78
  79         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  80         if (ret_buf) {
  81                 atomic_inc(&sesInfoAllocCount);
  82                 ret_buf->status = CifsNew;
  83                 ++ret_buf->ses_count;
  84                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  85                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  86                 mutex_init(&ret_buf->session_mutex);
  87         }
  88         return ret_buf;
  89 }
  90
  91 void
  92 sesInfoFree(struct cifs_ses *buf_to_free)
  93 {
  94         if (buf_to_free == NULL) {
  95                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  96                 return;
  97         }
  98
  99         atomic_dec(&sesInfoAllocCount);
 100         kfree(buf_to_free->serverOS);
 101         kfree(buf_to_free->serverDomain);
 102         kfree(buf_to_free->serverNOS);
 103         if (buf_to_free->password) {
 104                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 105                 kfree(buf_to_free->password);
 106         }
 107         kfree(buf_to_free->user_name);
 108         kfree(buf_to_free->domainName);
 109         kfree(buf_to_free->auth_key.response);
 110         kfree(buf_to_free);
 111 }
 112
 113 struct cifs_tcon *
 114 tconInfoAlloc(void)
 115 {
 116         struct cifs_tcon *ret_buf;
 117         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
 118         if (ret_buf) {
 119                 atomic_inc(&tconInfoAllocCount);
 120                 ret_buf->tidStatus = CifsNew;
 121                 ++ret_buf->tc_count;
 122                 INIT_LIST_HEAD(&ret_buf->openFileList);
 123                 INIT_LIST_HEAD(&ret_buf->tcon_list);
 124                 spin_lock_init(&ret_buf->open_file_lock);
 125 #ifdef CONFIG_CIFS_STATS
 126                 spin_lock_init(&ret_buf->stat_lock);
 127 #endif
 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         if (buf_to_free->password) {
 142                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 143                 kfree(buf_to_free->password);
 144         }
 145         kfree(buf_to_free);
 146 }
 147
 148 struct smb_hdr *
 149 cifs_buf_get(void)
 150 {
 151         struct smb_hdr *ret_buf = NULL;
 152         size_t buf_size = sizeof(struct smb_hdr);
 153
 154 #ifdef CONFIG_CIFS_SMB2
 155         /*
 156          * SMB2 header is bigger than CIFS one - no problems to clean some
 157          * more bytes for CIFS.
 158          */
 159         buf_size = sizeof(struct smb2_hdr);
 160 #endif
 161         /*
 162          * We could use negotiated size instead of max_msgsize -
 163          * but it may be more efficient to always alloc same size
 164          * albeit slightly larger than necessary and maxbuffersize
 165          * defaults to this and can not be bigger.
 166          */
 167         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 168
 169         /* clear the first few header bytes */
 170         /* for most paths, more is cleared in header_assemble */
 171         memset(ret_buf, 0, buf_size + 3);
 172         atomic_inc(&bufAllocCount);
 173 #ifdef CONFIG_CIFS_STATS2
 174         atomic_inc(&totBufAllocCount);
 175 #endif /* CONFIG_CIFS_STATS2 */
 176
 177         return ret_buf;
 178 }
 179
 180 void
 181 cifs_buf_release(void *buf_to_free)
 182 {
 183         if (buf_to_free == NULL) {
 184                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 185                 return;
 186         }
 187         mempool_free(buf_to_free, cifs_req_poolp);
 188
 189         atomic_dec(&bufAllocCount);
 190         return;
 191 }
 192
 193 struct smb_hdr *
 194 cifs_small_buf_get(void)
 195 {
 196         struct smb_hdr *ret_buf = NULL;
 197
 198 /* We could use negotiated size instead of max_msgsize -
 199    but it may be more efficient to always alloc same size
 200    albeit slightly larger than necessary and maxbuffersize
 201    defaults to this and can not be bigger */
 202         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 203         /* No need to clear memory here, cleared in header assemble */
 204         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 205         atomic_inc(&smBufAllocCount);
 206 #ifdef CONFIG_CIFS_STATS2
 207         atomic_inc(&totSmBufAllocCount);
 208 #endif /* CONFIG_CIFS_STATS2 */
 209
 210         return ret_buf;
 211 }
 212
 213 void
 214 cifs_small_buf_release(void *buf_to_free)
 215 {
 216
 217         if (buf_to_free == NULL) {
 218                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 219                 return;
 220         }
 221         mempool_free(buf_to_free, cifs_sm_req_poolp);
 222
 223         atomic_dec(&smBufAllocCount);
 224         return;
 225 }
 226
 227 void
 228 free_rsp_buf(int resp_buftype, void *rsp)
 229 {
 230         if (resp_buftype == CIFS_SMALL_BUFFER)
 231                 cifs_small_buf_release(rsp);
 232         else if (resp_buftype == CIFS_LARGE_BUFFER)
 233                 cifs_buf_release(rsp);
 234 }
 235
 236 /* NB: MID can not be set if treeCon not passed in, in that
 237    case it is responsbility of caller to set the mid */
 238 void
 239 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 240                 const struct cifs_tcon *treeCon, int word_count
 241                 /* length of fixed section (word count) in two byte units  */)
 242 {
 243         char *temp = (char *) buffer;
 244
 245         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 246
 247         buffer->smb_buf_length = cpu_to_be32(
 248             (2 * word_count) + sizeof(struct smb_hdr) -
 249             4 /*  RFC 1001 length field does not count */  +
 250             2 /* for bcc field itself */) ;
 251
 252         buffer->Protocol[0] = 0xFF;
 253         buffer->Protocol[1] = 'S';
 254         buffer->Protocol[2] = 'M';
 255         buffer->Protocol[3] = 'B';
 256         buffer->Command = smb_command;
 257         buffer->Flags = 0x00;   /* case sensitive */
 258         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 259         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 260         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 261         if (treeCon) {
 262                 buffer->Tid = treeCon->tid;
 263                 if (treeCon->ses) {
 264                         if (treeCon->ses->capabilities & CAP_UNICODE)
 265                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 266                         if (treeCon->ses->capabilities & CAP_STATUS32)
 267                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 268
 269                         /* Uid is not converted */
 270                         buffer->Uid = treeCon->ses->Suid;
 271                         buffer->Mid = get_next_mid(treeCon->ses->server);
 272                 }
 273                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 274                         buffer->Flags2 |= SMBFLG2_DFS;
 275                 if (treeCon->nocase)
 276                         buffer->Flags  |= SMBFLG_CASELESS;
 277                 if ((treeCon->ses) && (treeCon->ses->server))
 278                         if (treeCon->ses->server->sign)
 279                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 280         }
 281
 282 /*  endian conversion of flags is now done just before sending */
 283         buffer->WordCount = (char) word_count;
 284         return;
 285 }
 286
 287 static int
 288 check_smb_hdr(struct smb_hdr *smb)
 289 {
 290         /* does it have the right SMB "signature" ? */
 291         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 292                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 293                          *(unsigned int *)smb->Protocol);
 294                 return 1;
 295         }
 296
 297         /* if it's a response then accept */
 298         if (smb->Flags & SMBFLG_RESPONSE)
 299                 return 0;
 300
 301         /* only one valid case where server sends us request */
 302         if (smb->Command == SMB_COM_LOCKING_ANDX)
 303                 return 0;
 304
 305         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 306                  get_mid(smb));
 307         return 1;
 308 }
 309
 310 int
 311 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 312 {
 313         struct smb_hdr *smb = (struct smb_hdr *)buf;
 314         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 315         __u32 clc_len;  /* calculated length */
 316         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 317                  total_read, rfclen);
 318
 319         /* is this frame too small to even get to a BCC? */
 320         if (total_read < 2 + sizeof(struct smb_hdr)) {
 321                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 322                             && (smb->Status.CifsError != 0)) {
 323                         /* it's an error return */
 324                         smb->WordCount = 0;
 325                         /* some error cases do not return wct and bcc */
 326                         return 0;
 327                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 328                                 (smb->WordCount == 0)) {
 329                         char *tmp = (char *)smb;
 330                         /* Need to work around a bug in two servers here */
 331                         /* First, check if the part of bcc they sent was zero */
 332                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 333                                 /* some servers return only half of bcc
 334                                  * on simple responses (wct, bcc both zero)
 335                                  * in particular have seen this on
 336                                  * ulogoffX and FindClose. This leaves
 337                                  * one byte of bcc potentially unitialized
 338                                  */
 339                                 /* zero rest of bcc */
 340                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 341                                 return 0;
 342                         }
 343                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 344                 } else {
 345                         cifs_dbg(VFS, "Length less than smb header size\n");
 346                 }
 347                 return -EIO;
 348         }
 349
 350         /* otherwise, there is enough to get to the BCC */
 351         if (check_smb_hdr(smb))
 352                 return -EIO;
 353         clc_len = smbCalcSize(smb);
 354
 355         if (4 + rfclen != total_read) {
 356                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 357                          rfclen);
 358                 return -EIO;
 359         }
 360
 361         if (4 + rfclen != clc_len) {
 362                 __u16 mid = get_mid(smb);
 363                 /* check if bcc wrapped around for large read responses */
 364                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 365                         /* check if lengths match mod 64K */
 366                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 367                                 return 0; /* bcc wrapped */
 368                 }
 369                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 370                          clc_len, 4 + rfclen, mid);
 371
 372                 if (4 + rfclen < clc_len) {
 373                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 374                                  rfclen, mid);
 375                         return -EIO;
 376                 } else if (rfclen > clc_len + 512) {
 377                         /*
 378                          * Some servers (Windows XP in particular) send more
 379                          * data than the lengths in the SMB packet would
 380                          * indicate on certain calls (byte range locks and
 381                          * trans2 find first calls in particular). While the
 382                          * client can handle such a frame by ignoring the
 383                          * trailing data, we choose limit the amount of extra
 384                          * data to 512 bytes.
 385                          */
 386                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 387                                  rfclen, mid);
 388                         return -EIO;
 389                 }
 390         }
 391         return 0;
 392 }
 393
 394 bool
 395 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 396 {
 397         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 398         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 399         struct list_head *tmp, *tmp1, *tmp2;
 400         struct cifs_ses *ses;
 401         struct cifs_tcon *tcon;
 402         struct cifsInodeInfo *pCifsInode;
 403         struct cifsFileInfo *netfile;
 404
 405         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 406         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 407            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 408                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 409                         (struct smb_com_transaction_change_notify_rsp *)buf;
 410                 struct file_notify_information *pnotify;
 411                 __u32 data_offset = 0;
 412                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 413                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 414
 415                         pnotify = (struct file_notify_information *)
 416                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 417                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 418                                  pnotify->FileName, pnotify->Action);
 419                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 420                                 sizeof(struct smb_hdr)+60); */
 421                         return true;
 422                 }
 423                 if (pSMBr->hdr.Status.CifsError) {
 424                         cifs_dbg(FYI, "notify err 0x%x\n",
 425                                  pSMBr->hdr.Status.CifsError);
 426                         return true;
 427                 }
 428                 return false;
 429         }
 430         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 431                 return false;
 432         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 433                 /* no sense logging error on invalid handle on oplock
 434                    break - harmless race between close request and oplock
 435                    break response is expected from time to time writing out
 436                    large dirty files cached on the client */
 437                 if ((NT_STATUS_INVALID_HANDLE) ==
 438                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 439                         cifs_dbg(FYI, "invalid handle on oplock break\n");
 440                         return true;
 441                 } else if (ERRbadfid ==
 442                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 443                         return true;
 444                 } else {
 445                         return false; /* on valid oplock brk we get "request" */
 446                 }
 447         }
 448         if (pSMB->hdr.WordCount != 8)
 449                 return false;
 450
 451         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 452                  pSMB->LockType, pSMB->OplockLevel);
 453         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 454                 return false;
 455
 456         /* look up tcon based on tid & uid */
 457         spin_lock(&cifs_tcp_ses_lock);
 458         list_for_each(tmp, &srv->smb_ses_list) {
 459                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 460                 list_for_each(tmp1, &ses->tcon_list) {
 461                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 462                         if (tcon->tid != buf->Tid)
 463                                 continue;
 464
 465                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 466                         spin_lock(&tcon->open_file_lock);
 467                         list_for_each(tmp2, &tcon->openFileList) {
 468                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 469                                                      tlist);
 470                                 if (pSMB->Fid != netfile->fid.netfid)
 471                                         continue;
 472
 473                                 cifs_dbg(FYI, "file id match, oplock break\n");
 474                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 475
 476                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 477                                         &pCifsInode->flags);
 478
 479                                 /*
 480                                  * Set flag if the server downgrades the oplock
 481                                  * to L2 else clear.
 482                                  */
 483                                 if (pSMB->OplockLevel)
 484                                         set_bit(
 485                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 486                                            &pCifsInode->flags);
 487                                 else
 488                                         clear_bit(
 489                                            CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 490                                            &pCifsInode->flags);
 491
 492                                 queue_work(cifsoplockd_wq,
 493                                            &netfile->oplock_break);
 494                                 netfile->oplock_break_cancelled = false;
 495
 496                                 spin_unlock(&tcon->open_file_lock);
 497                                 spin_unlock(&cifs_tcp_ses_lock);
 498                                 return true;
 499                         }
 500                         spin_unlock(&tcon->open_file_lock);
 501                         spin_unlock(&cifs_tcp_ses_lock);
 502                         cifs_dbg(FYI, "No matching file for oplock break\n");
 503                         return true;
 504                 }
 505         }
 506         spin_unlock(&cifs_tcp_ses_lock);
 507         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 508         return true;
 509 }
 510
 511 void
 512 dump_smb(void *buf, int smb_buf_length)
 513 {
 514         if (traceSMB == 0)
 515                 return;
 516
 517         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 518                        smb_buf_length, true);
 519 }
 520
 521 void
 522 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 523 {
 524         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 525                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 526                 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",
 527                          cifs_sb_master_tcon(cifs_sb)->treeName);
 528         }
 529 }
 530
 531 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 532 {
 533         oplock &= 0xF;
 534
 535         if (oplock == OPLOCK_EXCLUSIVE) {
 536                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 537                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 538                          &cinode->vfs_inode);
 539         } else if (oplock == OPLOCK_READ) {
 540                 cinode->oplock = CIFS_CACHE_READ_FLG;
 541                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 542                          &cinode->vfs_inode);
 543         } else
 544                 cinode->oplock = 0;
 545 }
 546
 547 /*
 548  * We wait for oplock breaks to be processed before we attempt to perform
 549  * writes.
 550  */
 551 int cifs_get_writer(struct cifsInodeInfo *cinode)
 552 {
 553         int rc;
 554
 555 start:
 556         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 557                          TASK_KILLABLE);
 558         if (rc)
 559                 return rc;
 560
 561         spin_lock(&cinode->writers_lock);
 562         if (!cinode->writers)
 563                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 564         cinode->writers++;
 565         /* Check to see if we have started servicing an oplock break */
 566         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 567                 cinode->writers--;
 568                 if (cinode->writers == 0) {
 569                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 570                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 571                 }
 572                 spin_unlock(&cinode->writers_lock);
 573                 goto start;
 574         }
 575         spin_unlock(&cinode->writers_lock);
 576         return 0;
 577 }
 578
 579 void cifs_put_writer(struct cifsInodeInfo *cinode)
 580 {
 581         spin_lock(&cinode->writers_lock);
 582         cinode->writers--;
 583         if (cinode->writers == 0) {
 584                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 585                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 586         }
 587         spin_unlock(&cinode->writers_lock);
 588 }
 589
 590 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 591 {
 592         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 593         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 594 }
 595
 596 bool
 597 backup_cred(struct cifs_sb_info *cifs_sb)
 598 {
 599         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 600                 if (uid_eq(cifs_sb->mnt_backupuid, current_fsuid()))
 601                         return true;
 602         }
 603         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 604                 if (in_group_p(cifs_sb->mnt_backupgid))
 605                         return true;
 606         }
 607
 608         return false;
 609 }
 610
 611 void
 612 cifs_del_pending_open(struct cifs_pending_open *open)
 613 {
 614         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 615         list_del(&open->olist);
 616         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 617 }
 618
 619 void
 620 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 621                              struct cifs_pending_open *open)
 622 {
 623 #ifdef CONFIG_CIFS_SMB2
 624         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 625 #endif
 626         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 627         open->tlink = tlink;
 628         fid->pending_open = open;
 629         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 630 }
 631
 632 void
 633 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 634                       struct cifs_pending_open *open)
 635 {
 636         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 637         cifs_add_pending_open_locked(fid, tlink, open);
 638         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 639 }
 640
 641 /* parses DFS refferal V3 structure
 642  * caller is responsible for freeing target_nodes
 643  * returns:
 644  * - on success - 0
 645  * - on failure - errno
 646  */
 647 int
 648 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 649                     unsigned int *num_of_nodes,
 650                     struct dfs_info3_param **target_nodes,
 651                     const struct nls_table *nls_codepage, int remap,
 652                     const char *searchName, bool is_unicode)
 653 {
 654         int i, rc = 0;
 655         char *data_end;
 656         struct dfs_referral_level_3 *ref;
 657
 658         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 659
 660         if (*num_of_nodes < 1) {
 661                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 662                          *num_of_nodes);
 663                 rc = -EINVAL;
 664                 goto parse_DFS_referrals_exit;
 665         }
 666
 667         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 668         if (ref->VersionNumber != cpu_to_le16(3)) {
 669                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 670                          le16_to_cpu(ref->VersionNumber));
 671                 rc = -EINVAL;
 672                 goto parse_DFS_referrals_exit;
 673         }
 674
 675         /* get the upper boundary of the resp buffer */
 676         data_end = (char *)rsp + rsp_size;
 677
 678         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 679                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 680
 681         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 682                                 GFP_KERNEL);
 683         if (*target_nodes == NULL) {
 684                 rc = -ENOMEM;
 685                 goto parse_DFS_referrals_exit;
 686         }
 687
 688         /* collect necessary data from referrals */
 689         for (i = 0; i < *num_of_nodes; i++) {
 690                 char *temp;
 691                 int max_len;
 692                 struct dfs_info3_param *node = (*target_nodes)+i;
 693
 694                 node->flags = le32_to_cpu(rsp->DFSFlags);
 695                 if (is_unicode) {
 696                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 697                                                 GFP_KERNEL);
 698                         if (tmp == NULL) {
 699                                 rc = -ENOMEM;
 700                                 goto parse_DFS_referrals_exit;
 701                         }
 702                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 703                                            PATH_MAX, nls_codepage, remap);
 704                         node->path_consumed = cifs_utf16_bytes(tmp,
 705                                         le16_to_cpu(rsp->PathConsumed),
 706                                         nls_codepage);
 707                         kfree(tmp);
 708                 } else
 709                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 710
 711                 node->server_type = le16_to_cpu(ref->ServerType);
 712                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 713
 714                 /* copy DfsPath */
 715                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 716                 max_len = data_end - temp;
 717                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 718                                                 is_unicode, nls_codepage);
 719                 if (!node->path_name) {
 720                         rc = -ENOMEM;
 721                         goto parse_DFS_referrals_exit;
 722                 }
 723
 724                 /* copy link target UNC */
 725                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 726                 max_len = data_end - temp;
 727                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 728                                                 is_unicode, nls_codepage);
 729                 if (!node->node_name) {
 730                         rc = -ENOMEM;
 731                         goto parse_DFS_referrals_exit;
 732                 }
 733
 734                 ref++;
 735         }
 736
 737 parse_DFS_referrals_exit:
 738         if (rc) {
 739                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 740                 *target_nodes = NULL;
 741                 *num_of_nodes = 0;
 742         }
 743         return rc;
 744 }
 745
 746 struct cifs_aio_ctx *
 747 cifs_aio_ctx_alloc(void)
 748 {
 749         struct cifs_aio_ctx *ctx;
 750
 751         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 752         if (!ctx)
 753                 return NULL;
 754
 755         INIT_LIST_HEAD(&ctx->list);
 756         mutex_init(&ctx->aio_mutex);
 757         init_completion(&ctx->done);
 758         kref_init(&ctx->refcount);
 759         return ctx;
 760 }
 761
 762 void
 763 cifs_aio_ctx_release(struct kref *refcount)
 764 {
 765         struct cifs_aio_ctx *ctx = container_of(refcount,
 766                                         struct cifs_aio_ctx, refcount);
 767
 768         cifsFileInfo_put(ctx->cfile);
 769         kvfree(ctx->bv);
 770         kfree(ctx);
 771 }
 772
 773 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
 774
 775 int
 776 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 777 {
 778         ssize_t rc;
 779         unsigned int cur_npages;
 780         unsigned int npages = 0;
 781         unsigned int i;
 782         size_t len;
 783         size_t count = iov_iter_count(iter);
 784         unsigned int saved_len;
 785         size_t start;
 786         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
 787         struct page **pages = NULL;
 788         struct bio_vec *bv = NULL;
 789
 790         if (iter->type & ITER_KVEC) {
 791                 memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
 792                 ctx->len = count;
 793                 iov_iter_advance(iter, count);
 794                 return 0;
 795         }
 796
 797         if (max_pages * sizeof(struct bio_vec) <= CIFS_AIO_KMALLOC_LIMIT)
 798                 bv = kmalloc_array(max_pages, sizeof(struct bio_vec),
 799                                    GFP_KERNEL);
 800
 801         if (!bv) {
 802                 bv = vmalloc(max_pages * sizeof(struct bio_vec));
 803                 if (!bv)
 804                         return -ENOMEM;
 805         }
 806
 807         if (max_pages * sizeof(struct page *) <= CIFS_AIO_KMALLOC_LIMIT)
 808                 pages = kmalloc_array(max_pages, sizeof(struct page *),
 809                                       GFP_KERNEL);
 810
 811         if (!pages) {
 812                 pages = vmalloc(max_pages * sizeof(struct page *));
 813                 if (!bv) {
 814                         kvfree(bv);
 815                         return -ENOMEM;
 816                 }
 817         }
 818
 819         saved_len = count;
 820
 821         while (count && npages < max_pages) {
 822                 rc = iov_iter_get_pages(iter, pages, count, max_pages, &start);
 823                 if (rc < 0) {
 824                         cifs_dbg(VFS, "couldn't get user pages (rc=%zd)\n", rc);
 825                         break;
 826                 }
 827
 828                 if (rc > count) {
 829                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
 830                                  count);
 831                         break;
 832                 }
 833
 834                 iov_iter_advance(iter, rc);
 835                 count -= rc;
 836                 rc += start;
 837                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
 838
 839                 if (npages + cur_npages > max_pages) {
 840                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
 841                                  npages + cur_npages, max_pages);
 842                         break;
 843                 }
 844
 845                 for (i = 0; i < cur_npages; i++) {
 846                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
 847                         bv[npages + i].bv_page = pages[i];
 848                         bv[npages + i].bv_offset = start;
 849                         bv[npages + i].bv_len = len - start;
 850                         rc -= len;
 851                         start = 0;
 852                 }
 853
 854                 npages += cur_npages;
 855         }
 856
 857         kvfree(pages);
 858         ctx->bv = bv;
 859         ctx->len = saved_len - count;
 860         ctx->npages = npages;
 861         iov_iter_bvec(&ctx->iter, ITER_BVEC | rw, ctx->bv, npages, ctx->len);
 862         return 0;
 863 }