fs/smb/client/misc.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  */
   8
   9 #include <linux/slab.h>
  10 #include <linux/ctype.h>
  11 #include <linux/mempool.h>
  12 #include <linux/vmalloc.h>
  13 #include "cifspdu.h"
  14 #include "cifsglob.h"
  15 #include "cifsproto.h"
  16 #include "cifs_debug.h"
  17 #include "smberr.h"
  18 #include "nterr.h"
  19 #include "cifs_unicode.h"
  20 #include "smb2pdu.h"
  21 #include "cifsfs.h"
  22 #ifdef CONFIG_CIFS_DFS_UPCALL
  23 #include "dns_resolve.h"
  24 #include "dfs_cache.h"
  25 #include "dfs.h"
  26 #endif
  27 #include "fs_context.h"
  28 #include "cached_dir.h"
  29
  30 /* The xid serves as a useful identifier for each incoming vfs request,
  31    in a similar way to the mid which is useful to track each sent smb,
  32    and CurrentXid can also provide a running counter (although it
  33    will eventually wrap past zero) of the total vfs operations handled
  34    since the cifs fs was mounted */
  35
  36 unsigned int
  37 _get_xid(void)
  38 {
  39         unsigned int xid;
  40
  41         spin_lock(&GlobalMid_Lock);
  42         GlobalTotalActiveXid++;
  43
  44         /* keep high water mark for number of simultaneous ops in filesystem */
  45         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  46                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  47         if (GlobalTotalActiveXid > 65000)
  48                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  49         xid = GlobalCurrentXid++;
  50         spin_unlock(&GlobalMid_Lock);
  51         return xid;
  52 }
  53
  54 void
  55 _free_xid(unsigned int xid)
  56 {
  57         spin_lock(&GlobalMid_Lock);
  58         /* if (GlobalTotalActiveXid == 0)
  59                 BUG(); */
  60         GlobalTotalActiveXid--;
  61         spin_unlock(&GlobalMid_Lock);
  62 }
  63
  64 struct cifs_ses *
  65 sesInfoAlloc(void)
  66 {
  67         struct cifs_ses *ret_buf;
  68
  69         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  70         if (ret_buf) {
  71                 atomic_inc(&sesInfoAllocCount);
  72                 spin_lock_init(&ret_buf->ses_lock);
  73                 ret_buf->ses_status = SES_NEW;
  74                 ++ret_buf->ses_count;
  75                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  76                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  77                 mutex_init(&ret_buf->session_mutex);
  78                 spin_lock_init(&ret_buf->iface_lock);
  79                 INIT_LIST_HEAD(&ret_buf->iface_list);
  80                 spin_lock_init(&ret_buf->chan_lock);
  81         }
  82         return ret_buf;
  83 }
  84
  85 void
  86 sesInfoFree(struct cifs_ses *buf_to_free)
  87 {
  88         struct cifs_server_iface *iface = NULL, *niface = NULL;
  89
  90         if (buf_to_free == NULL) {
  91                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  92                 return;
  93         }
  94
  95         unload_nls(buf_to_free->local_nls);
  96         atomic_dec(&sesInfoAllocCount);
  97         kfree(buf_to_free->serverOS);
  98         kfree(buf_to_free->serverDomain);
  99         kfree(buf_to_free->serverNOS);
 100         kfree_sensitive(buf_to_free->password);
 101         kfree(buf_to_free->user_name);
 102         kfree(buf_to_free->domainName);
 103         kfree_sensitive(buf_to_free->auth_key.response);
 104         spin_lock(&buf_to_free->iface_lock);
 105         list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
 106                                  iface_head)
 107                 kref_put(&iface->refcount, release_iface);
 108         spin_unlock(&buf_to_free->iface_lock);
 109         kfree_sensitive(buf_to_free);
 110 }
 111
 112 struct cifs_tcon *
 113 tcon_info_alloc(bool dir_leases_enabled)
 114 {
 115         struct cifs_tcon *ret_buf;
 116
 117         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 118         if (!ret_buf)
 119                 return NULL;
 120
 121         if (dir_leases_enabled == true) {
 122                 ret_buf->cfids = init_cached_dirs();
 123                 if (!ret_buf->cfids) {
 124                         kfree(ret_buf);
 125                         return NULL;
 126                 }
 127         }
 128         /* else ret_buf->cfids is already set to NULL above */
 129
 130         atomic_inc(&tconInfoAllocCount);
 131         ret_buf->status = TID_NEW;
 132         ++ret_buf->tc_count;
 133         spin_lock_init(&ret_buf->tc_lock);
 134         INIT_LIST_HEAD(&ret_buf->openFileList);
 135         INIT_LIST_HEAD(&ret_buf->tcon_list);
 136         spin_lock_init(&ret_buf->open_file_lock);
 137         spin_lock_init(&ret_buf->stat_lock);
 138         atomic_set(&ret_buf->num_local_opens, 0);
 139         atomic_set(&ret_buf->num_remote_opens, 0);
 140         ret_buf->stats_from_time = ktime_get_real_seconds();
 141 #ifdef CONFIG_CIFS_DFS_UPCALL
 142         INIT_LIST_HEAD(&ret_buf->dfs_ses_list);
 143 #endif
 144
 145         return ret_buf;
 146 }
 147
 148 void
 149 tconInfoFree(struct cifs_tcon *tcon)
 150 {
 151         if (tcon == NULL) {
 152                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 153                 return;
 154         }
 155         free_cached_dirs(tcon->cfids);
 156         atomic_dec(&tconInfoAllocCount);
 157         kfree(tcon->nativeFileSystem);
 158         kfree_sensitive(tcon->password);
 159 #ifdef CONFIG_CIFS_DFS_UPCALL
 160         dfs_put_root_smb_sessions(&tcon->dfs_ses_list);
 161 #endif
 162         kfree(tcon->origin_fullpath);
 163         kfree(tcon);
 164 }
 165
 166 struct smb_hdr *
 167 cifs_buf_get(void)
 168 {
 169         struct smb_hdr *ret_buf = NULL;
 170         /*
 171          * SMB2 header is bigger than CIFS one - no problems to clean some
 172          * more bytes for CIFS.
 173          */
 174         size_t buf_size = sizeof(struct smb2_hdr);
 175
 176         /*
 177          * We could use negotiated size instead of max_msgsize -
 178          * but it may be more efficient to always alloc same size
 179          * albeit slightly larger than necessary and maxbuffersize
 180          * defaults to this and can not be bigger.
 181          */
 182         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 183
 184         /* clear the first few header bytes */
 185         /* for most paths, more is cleared in header_assemble */
 186         memset(ret_buf, 0, buf_size + 3);
 187         atomic_inc(&buf_alloc_count);
 188 #ifdef CONFIG_CIFS_STATS2
 189         atomic_inc(&total_buf_alloc_count);
 190 #endif /* CONFIG_CIFS_STATS2 */
 191
 192         return ret_buf;
 193 }
 194
 195 void
 196 cifs_buf_release(void *buf_to_free)
 197 {
 198         if (buf_to_free == NULL) {
 199                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 200                 return;
 201         }
 202         mempool_free(buf_to_free, cifs_req_poolp);
 203
 204         atomic_dec(&buf_alloc_count);
 205         return;
 206 }
 207
 208 struct smb_hdr *
 209 cifs_small_buf_get(void)
 210 {
 211         struct smb_hdr *ret_buf = NULL;
 212
 213 /* We could use negotiated size instead of max_msgsize -
 214    but it may be more efficient to always alloc same size
 215    albeit slightly larger than necessary and maxbuffersize
 216    defaults to this and can not be bigger */
 217         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 218         /* No need to clear memory here, cleared in header assemble */
 219         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 220         atomic_inc(&small_buf_alloc_count);
 221 #ifdef CONFIG_CIFS_STATS2
 222         atomic_inc(&total_small_buf_alloc_count);
 223 #endif /* CONFIG_CIFS_STATS2 */
 224
 225         return ret_buf;
 226 }
 227
 228 void
 229 cifs_small_buf_release(void *buf_to_free)
 230 {
 231
 232         if (buf_to_free == NULL) {
 233                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 234                 return;
 235         }
 236         mempool_free(buf_to_free, cifs_sm_req_poolp);
 237
 238         atomic_dec(&small_buf_alloc_count);
 239         return;
 240 }
 241
 242 void
 243 free_rsp_buf(int resp_buftype, void *rsp)
 244 {
 245         if (resp_buftype == CIFS_SMALL_BUFFER)
 246                 cifs_small_buf_release(rsp);
 247         else if (resp_buftype == CIFS_LARGE_BUFFER)
 248                 cifs_buf_release(rsp);
 249 }
 250
 251 /* NB: MID can not be set if treeCon not passed in, in that
 252    case it is responsbility of caller to set the mid */
 253 void
 254 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 255                 const struct cifs_tcon *treeCon, int word_count
 256                 /* length of fixed section (word count) in two byte units  */)
 257 {
 258         char *temp = (char *) buffer;
 259
 260         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 261
 262         buffer->smb_buf_length = cpu_to_be32(
 263             (2 * word_count) + sizeof(struct smb_hdr) -
 264             4 /*  RFC 1001 length field does not count */  +
 265             2 /* for bcc field itself */) ;
 266
 267         buffer->Protocol[0] = 0xFF;
 268         buffer->Protocol[1] = 'S';
 269         buffer->Protocol[2] = 'M';
 270         buffer->Protocol[3] = 'B';
 271         buffer->Command = smb_command;
 272         buffer->Flags = 0x00;   /* case sensitive */
 273         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 274         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 275         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 276         if (treeCon) {
 277                 buffer->Tid = treeCon->tid;
 278                 if (treeCon->ses) {
 279                         if (treeCon->ses->capabilities & CAP_UNICODE)
 280                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 281                         if (treeCon->ses->capabilities & CAP_STATUS32)
 282                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 283
 284                         /* Uid is not converted */
 285                         buffer->Uid = treeCon->ses->Suid;
 286                         if (treeCon->ses->server)
 287                                 buffer->Mid = get_next_mid(treeCon->ses->server);
 288                 }
 289                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 290                         buffer->Flags2 |= SMBFLG2_DFS;
 291                 if (treeCon->nocase)
 292                         buffer->Flags  |= SMBFLG_CASELESS;
 293                 if ((treeCon->ses) && (treeCon->ses->server))
 294                         if (treeCon->ses->server->sign)
 295                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 296         }
 297
 298 /*  endian conversion of flags is now done just before sending */
 299         buffer->WordCount = (char) word_count;
 300         return;
 301 }
 302
 303 static int
 304 check_smb_hdr(struct smb_hdr *smb)
 305 {
 306         /* does it have the right SMB "signature" ? */
 307         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 308                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 309                          *(unsigned int *)smb->Protocol);
 310                 return 1;
 311         }
 312
 313         /* if it's a response then accept */
 314         if (smb->Flags & SMBFLG_RESPONSE)
 315                 return 0;
 316
 317         /* only one valid case where server sends us request */
 318         if (smb->Command == SMB_COM_LOCKING_ANDX)
 319                 return 0;
 320
 321         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 322                  get_mid(smb));
 323         return 1;
 324 }
 325
 326 int
 327 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 328 {
 329         struct smb_hdr *smb = (struct smb_hdr *)buf;
 330         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 331         __u32 clc_len;  /* calculated length */
 332         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 333                  total_read, rfclen);
 334
 335         /* is this frame too small to even get to a BCC? */
 336         if (total_read < 2 + sizeof(struct smb_hdr)) {
 337                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 338                             && (smb->Status.CifsError != 0)) {
 339                         /* it's an error return */
 340                         smb->WordCount = 0;
 341                         /* some error cases do not return wct and bcc */
 342                         return 0;
 343                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 344                                 (smb->WordCount == 0)) {
 345                         char *tmp = (char *)smb;
 346                         /* Need to work around a bug in two servers here */
 347                         /* First, check if the part of bcc they sent was zero */
 348                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 349                                 /* some servers return only half of bcc
 350                                  * on simple responses (wct, bcc both zero)
 351                                  * in particular have seen this on
 352                                  * ulogoffX and FindClose. This leaves
 353                                  * one byte of bcc potentially unitialized
 354                                  */
 355                                 /* zero rest of bcc */
 356                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 357                                 return 0;
 358                         }
 359                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 360                 } else {
 361                         cifs_dbg(VFS, "Length less than smb header size\n");
 362                 }
 363                 return -EIO;
 364         } else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
 365                 cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
 366                          __func__, smb->WordCount);
 367                 return -EIO;
 368         }
 369
 370         /* otherwise, there is enough to get to the BCC */
 371         if (check_smb_hdr(smb))
 372                 return -EIO;
 373         clc_len = smbCalcSize(smb);
 374
 375         if (4 + rfclen != total_read) {
 376                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 377                          rfclen);
 378                 return -EIO;
 379         }
 380
 381         if (4 + rfclen != clc_len) {
 382                 __u16 mid = get_mid(smb);
 383                 /* check if bcc wrapped around for large read responses */
 384                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 385                         /* check if lengths match mod 64K */
 386                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 387                                 return 0; /* bcc wrapped */
 388                 }
 389                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 390                          clc_len, 4 + rfclen, mid);
 391
 392                 if (4 + rfclen < clc_len) {
 393                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 394                                  rfclen, mid);
 395                         return -EIO;
 396                 } else if (rfclen > clc_len + 512) {
 397                         /*
 398                          * Some servers (Windows XP in particular) send more
 399                          * data than the lengths in the SMB packet would
 400                          * indicate on certain calls (byte range locks and
 401                          * trans2 find first calls in particular). While the
 402                          * client can handle such a frame by ignoring the
 403                          * trailing data, we choose limit the amount of extra
 404                          * data to 512 bytes.
 405                          */
 406                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 407                                  rfclen, mid);
 408                         return -EIO;
 409                 }
 410         }
 411         return 0;
 412 }
 413
 414 bool
 415 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 416 {
 417         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 418         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 419         struct TCP_Server_Info *pserver;
 420         struct cifs_ses *ses;
 421         struct cifs_tcon *tcon;
 422         struct cifsInodeInfo *pCifsInode;
 423         struct cifsFileInfo *netfile;
 424
 425         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 426         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 427            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 428                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 429                         (struct smb_com_transaction_change_notify_rsp *)buf;
 430                 struct file_notify_information *pnotify;
 431                 __u32 data_offset = 0;
 432                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 433
 434                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 435                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 436
 437                         if (data_offset >
 438                             len - sizeof(struct file_notify_information)) {
 439                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
 440                                          data_offset);
 441                                 return true;
 442                         }
 443                         pnotify = (struct file_notify_information *)
 444                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 445                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 446                                  pnotify->FileName, pnotify->Action);
 447                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 448                                 sizeof(struct smb_hdr)+60); */
 449                         return true;
 450                 }
 451                 if (pSMBr->hdr.Status.CifsError) {
 452                         cifs_dbg(FYI, "notify err 0x%x\n",
 453                                  pSMBr->hdr.Status.CifsError);
 454                         return true;
 455                 }
 456                 return false;
 457         }
 458         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 459                 return false;
 460         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 461                 /* no sense logging error on invalid handle on oplock
 462                    break - harmless race between close request and oplock
 463                    break response is expected from time to time writing out
 464                    large dirty files cached on the client */
 465                 if ((NT_STATUS_INVALID_HANDLE) ==
 466                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 467                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
 468                         return true;
 469                 } else if (ERRbadfid ==
 470                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 471                         return true;
 472                 } else {
 473                         return false; /* on valid oplock brk we get "request" */
 474                 }
 475         }
 476         if (pSMB->hdr.WordCount != 8)
 477                 return false;
 478
 479         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 480                  pSMB->LockType, pSMB->OplockLevel);
 481         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 482                 return false;
 483
 484         /* If server is a channel, select the primary channel */
 485         pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
 486
 487         /* look up tcon based on tid & uid */
 488         spin_lock(&cifs_tcp_ses_lock);
 489         list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 490                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 491                         if (tcon->tid != buf->Tid)
 492                                 continue;
 493
 494                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 495                         spin_lock(&tcon->open_file_lock);
 496                         list_for_each_entry(netfile, &tcon->openFileList, tlist) {
 497                                 if (pSMB->Fid != netfile->fid.netfid)
 498                                         continue;
 499
 500                                 cifs_dbg(FYI, "file id match, oplock break\n");
 501                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 502
 503                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 504                                         &pCifsInode->flags);
 505
 506                                 netfile->oplock_epoch = 0;
 507                                 netfile->oplock_level = pSMB->OplockLevel;
 508                                 netfile->oplock_break_cancelled = false;
 509                                 cifs_queue_oplock_break(netfile);
 510
 511                                 spin_unlock(&tcon->open_file_lock);
 512                                 spin_unlock(&cifs_tcp_ses_lock);
 513                                 return true;
 514                         }
 515                         spin_unlock(&tcon->open_file_lock);
 516                         spin_unlock(&cifs_tcp_ses_lock);
 517                         cifs_dbg(FYI, "No matching file for oplock break\n");
 518                         return true;
 519                 }
 520         }
 521         spin_unlock(&cifs_tcp_ses_lock);
 522         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 523         return true;
 524 }
 525
 526 void
 527 dump_smb(void *buf, int smb_buf_length)
 528 {
 529         if (traceSMB == 0)
 530                 return;
 531
 532         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 533                        smb_buf_length, true);
 534 }
 535
 536 void
 537 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 538 {
 539         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 540                 struct cifs_tcon *tcon = NULL;
 541
 542                 if (cifs_sb->master_tlink)
 543                         tcon = cifs_sb_master_tcon(cifs_sb);
 544
 545                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 546                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 547                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 548                          tcon ? tcon->tree_name : "new server");
 549                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 550                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 551
 552         }
 553 }
 554
 555 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 556 {
 557         oplock &= 0xF;
 558
 559         if (oplock == OPLOCK_EXCLUSIVE) {
 560                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 561                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 562                          &cinode->netfs.inode);
 563         } else if (oplock == OPLOCK_READ) {
 564                 cinode->oplock = CIFS_CACHE_READ_FLG;
 565                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 566                          &cinode->netfs.inode);
 567         } else
 568                 cinode->oplock = 0;
 569 }
 570
 571 /*
 572  * We wait for oplock breaks to be processed before we attempt to perform
 573  * writes.
 574  */
 575 int cifs_get_writer(struct cifsInodeInfo *cinode)
 576 {
 577         int rc;
 578
 579 start:
 580         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 581                          TASK_KILLABLE);
 582         if (rc)
 583                 return rc;
 584
 585         spin_lock(&cinode->writers_lock);
 586         if (!cinode->writers)
 587                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 588         cinode->writers++;
 589         /* Check to see if we have started servicing an oplock break */
 590         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 591                 cinode->writers--;
 592                 if (cinode->writers == 0) {
 593                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 594                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 595                 }
 596                 spin_unlock(&cinode->writers_lock);
 597                 goto start;
 598         }
 599         spin_unlock(&cinode->writers_lock);
 600         return 0;
 601 }
 602
 603 void cifs_put_writer(struct cifsInodeInfo *cinode)
 604 {
 605         spin_lock(&cinode->writers_lock);
 606         cinode->writers--;
 607         if (cinode->writers == 0) {
 608                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 609                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 610         }
 611         spin_unlock(&cinode->writers_lock);
 612 }
 613
 614 /**
 615  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 616  * @cfile: The file to break the oplock on
 617  *
 618  * This function is called from the demultiplex thread when it
 619  * receives an oplock break for @cfile.
 620  *
 621  * Assumes the tcon->open_file_lock is held.
 622  * Assumes cfile->file_info_lock is NOT held.
 623  */
 624 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 625 {
 626         /*
 627          * Bump the handle refcount now while we hold the
 628          * open_file_lock to enforce the validity of it for the oplock
 629          * break handler. The matching put is done at the end of the
 630          * handler.
 631          */
 632         cifsFileInfo_get(cfile);
 633
 634         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 635 }
 636
 637 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 638 {
 639         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 640         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 641 }
 642
 643 bool
 644 backup_cred(struct cifs_sb_info *cifs_sb)
 645 {
 646         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 647                 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
 648                         return true;
 649         }
 650         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 651                 if (in_group_p(cifs_sb->ctx->backupgid))
 652                         return true;
 653         }
 654
 655         return false;
 656 }
 657
 658 void
 659 cifs_del_pending_open(struct cifs_pending_open *open)
 660 {
 661         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 662         list_del(&open->olist);
 663         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 664 }
 665
 666 void
 667 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 668                              struct cifs_pending_open *open)
 669 {
 670         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 671         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 672         open->tlink = tlink;
 673         fid->pending_open = open;
 674         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 675 }
 676
 677 void
 678 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 679                       struct cifs_pending_open *open)
 680 {
 681         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 682         cifs_add_pending_open_locked(fid, tlink, open);
 683         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 684 }
 685
 686 /*
 687  * Critical section which runs after acquiring deferred_lock.
 688  * As there is no reference count on cifs_deferred_close, pdclose
 689  * should not be used outside deferred_lock.
 690  */
 691 bool
 692 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
 693 {
 694         struct cifs_deferred_close *dclose;
 695
 696         list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
 697                 if ((dclose->netfid == cfile->fid.netfid) &&
 698                         (dclose->persistent_fid == cfile->fid.persistent_fid) &&
 699                         (dclose->volatile_fid == cfile->fid.volatile_fid)) {
 700                         *pdclose = dclose;
 701                         return true;
 702                 }
 703         }
 704         return false;
 705 }
 706
 707 /*
 708  * Critical section which runs after acquiring deferred_lock.
 709  */
 710 void
 711 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
 712 {
 713         bool is_deferred = false;
 714         struct cifs_deferred_close *pdclose;
 715
 716         is_deferred = cifs_is_deferred_close(cfile, &pdclose);
 717         if (is_deferred) {
 718                 kfree(dclose);
 719                 return;
 720         }
 721
 722         dclose->tlink = cfile->tlink;
 723         dclose->netfid = cfile->fid.netfid;
 724         dclose->persistent_fid = cfile->fid.persistent_fid;
 725         dclose->volatile_fid = cfile->fid.volatile_fid;
 726         list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
 727 }
 728
 729 /*
 730  * Critical section which runs after acquiring deferred_lock.
 731  */
 732 void
 733 cifs_del_deferred_close(struct cifsFileInfo *cfile)
 734 {
 735         bool is_deferred = false;
 736         struct cifs_deferred_close *dclose;
 737
 738         is_deferred = cifs_is_deferred_close(cfile, &dclose);
 739         if (!is_deferred)
 740                 return;
 741         list_del(&dclose->dlist);
 742         kfree(dclose);
 743 }
 744
 745 void
 746 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
 747 {
 748         struct cifsFileInfo *cfile = NULL;
 749         struct file_list *tmp_list, *tmp_next_list;
 750         struct list_head file_head;
 751
 752         if (cifs_inode == NULL)
 753                 return;
 754
 755         INIT_LIST_HEAD(&file_head);
 756         spin_lock(&cifs_inode->open_file_lock);
 757         list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
 758                 if (delayed_work_pending(&cfile->deferred)) {
 759                         if (cancel_delayed_work(&cfile->deferred)) {
 760                                 spin_lock(&cifs_inode->deferred_lock);
 761                                 cifs_del_deferred_close(cfile);
 762                                 spin_unlock(&cifs_inode->deferred_lock);
 763
 764                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 765                                 if (tmp_list == NULL)
 766                                         break;
 767                                 tmp_list->cfile = cfile;
 768                                 list_add_tail(&tmp_list->list, &file_head);
 769                         }
 770                 }
 771         }
 772         spin_unlock(&cifs_inode->open_file_lock);
 773
 774         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 775                 _cifsFileInfo_put(tmp_list->cfile, false, false);
 776                 list_del(&tmp_list->list);
 777                 kfree(tmp_list);
 778         }
 779 }
 780
 781 void
 782 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 783 {
 784         struct cifsFileInfo *cfile;
 785         struct file_list *tmp_list, *tmp_next_list;
 786         struct list_head file_head;
 787
 788         INIT_LIST_HEAD(&file_head);
 789         spin_lock(&tcon->open_file_lock);
 790         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 791                 if (delayed_work_pending(&cfile->deferred)) {
 792                         if (cancel_delayed_work(&cfile->deferred)) {
 793                                 spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 794                                 cifs_del_deferred_close(cfile);
 795                                 spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 796
 797                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 798                                 if (tmp_list == NULL)
 799                                         break;
 800                                 tmp_list->cfile = cfile;
 801                                 list_add_tail(&tmp_list->list, &file_head);
 802                         }
 803                 }
 804         }
 805         spin_unlock(&tcon->open_file_lock);
 806
 807         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 808                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 809                 list_del(&tmp_list->list);
 810                 kfree(tmp_list);
 811         }
 812 }
 813 void
 814 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
 815 {
 816         struct cifsFileInfo *cfile;
 817         struct file_list *tmp_list, *tmp_next_list;
 818         struct list_head file_head;
 819         void *page;
 820         const char *full_path;
 821
 822         INIT_LIST_HEAD(&file_head);
 823         page = alloc_dentry_path();
 824         spin_lock(&tcon->open_file_lock);
 825         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 826                 full_path = build_path_from_dentry(cfile->dentry, page);
 827                 if (strstr(full_path, path)) {
 828                         if (delayed_work_pending(&cfile->deferred)) {
 829                                 if (cancel_delayed_work(&cfile->deferred)) {
 830                                         spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 831                                         cifs_del_deferred_close(cfile);
 832                                         spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 833
 834                                         tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 835                                         if (tmp_list == NULL)
 836                                                 break;
 837                                         tmp_list->cfile = cfile;
 838                                         list_add_tail(&tmp_list->list, &file_head);
 839                                 }
 840                         }
 841                 }
 842         }
 843         spin_unlock(&tcon->open_file_lock);
 844
 845         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 846                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 847                 list_del(&tmp_list->list);
 848                 kfree(tmp_list);
 849         }
 850         free_dentry_path(page);
 851 }
 852
 853 /*
 854  * If a dentry has been deleted, all corresponding open handles should know that
 855  * so that we do not defer close them.
 856  */
 857 void cifs_mark_open_handles_for_deleted_file(struct inode *inode,
 858                                              const char *path)
 859 {
 860         struct cifsFileInfo *cfile;
 861         void *page;
 862         const char *full_path;
 863         struct cifsInodeInfo *cinode = CIFS_I(inode);
 864
 865         page = alloc_dentry_path();
 866         spin_lock(&cinode->open_file_lock);
 867
 868         /*
 869          * note: we need to construct path from dentry and compare only if the
 870          * inode has any hardlinks. When number of hardlinks is 1, we can just
 871          * mark all open handles since they are going to be from the same file.
 872          */
 873         if (inode->i_nlink > 1) {
 874                 list_for_each_entry(cfile, &cinode->openFileList, flist) {
 875                         full_path = build_path_from_dentry(cfile->dentry, page);
 876                         if (!IS_ERR(full_path) && strcmp(full_path, path) == 0)
 877                                 cfile->status_file_deleted = true;
 878                 }
 879         } else {
 880                 list_for_each_entry(cfile, &cinode->openFileList, flist)
 881                         cfile->status_file_deleted = true;
 882         }
 883         spin_unlock(&cinode->open_file_lock);
 884         free_dentry_path(page);
 885 }
 886
 887 /* parses DFS referral V3 structure
 888  * caller is responsible for freeing target_nodes
 889  * returns:
 890  * - on success - 0
 891  * - on failure - errno
 892  */
 893 int
 894 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 895                     unsigned int *num_of_nodes,
 896                     struct dfs_info3_param **target_nodes,
 897                     const struct nls_table *nls_codepage, int remap,
 898                     const char *searchName, bool is_unicode)
 899 {
 900         int i, rc = 0;
 901         char *data_end;
 902         struct dfs_referral_level_3 *ref;
 903
 904         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 905
 906         if (*num_of_nodes < 1) {
 907                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 908                          *num_of_nodes);
 909                 rc = -EINVAL;
 910                 goto parse_DFS_referrals_exit;
 911         }
 912
 913         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 914         if (ref->VersionNumber != cpu_to_le16(3)) {
 915                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 916                          le16_to_cpu(ref->VersionNumber));
 917                 rc = -EINVAL;
 918                 goto parse_DFS_referrals_exit;
 919         }
 920
 921         /* get the upper boundary of the resp buffer */
 922         data_end = (char *)rsp + rsp_size;
 923
 924         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 925                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 926
 927         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 928                                 GFP_KERNEL);
 929         if (*target_nodes == NULL) {
 930                 rc = -ENOMEM;
 931                 goto parse_DFS_referrals_exit;
 932         }
 933
 934         /* collect necessary data from referrals */
 935         for (i = 0; i < *num_of_nodes; i++) {
 936                 char *temp;
 937                 int max_len;
 938                 struct dfs_info3_param *node = (*target_nodes)+i;
 939
 940                 node->flags = le32_to_cpu(rsp->DFSFlags);
 941                 if (is_unicode) {
 942                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 943                                                 GFP_KERNEL);
 944                         if (tmp == NULL) {
 945                                 rc = -ENOMEM;
 946                                 goto parse_DFS_referrals_exit;
 947                         }
 948                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 949                                            PATH_MAX, nls_codepage, remap);
 950                         node->path_consumed = cifs_utf16_bytes(tmp,
 951                                         le16_to_cpu(rsp->PathConsumed),
 952                                         nls_codepage);
 953                         kfree(tmp);
 954                 } else
 955                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 956
 957                 node->server_type = le16_to_cpu(ref->ServerType);
 958                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 959
 960                 /* copy DfsPath */
 961                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 962                 max_len = data_end - temp;
 963                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 964                                                 is_unicode, nls_codepage);
 965                 if (!node->path_name) {
 966                         rc = -ENOMEM;
 967                         goto parse_DFS_referrals_exit;
 968                 }
 969
 970                 /* copy link target UNC */
 971                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 972                 max_len = data_end - temp;
 973                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 974                                                 is_unicode, nls_codepage);
 975                 if (!node->node_name) {
 976                         rc = -ENOMEM;
 977                         goto parse_DFS_referrals_exit;
 978                 }
 979
 980                 node->ttl = le32_to_cpu(ref->TimeToLive);
 981
 982                 ref++;
 983         }
 984
 985 parse_DFS_referrals_exit:
 986         if (rc) {
 987                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 988                 *target_nodes = NULL;
 989                 *num_of_nodes = 0;
 990         }
 991         return rc;
 992 }
 993
 994 struct cifs_aio_ctx *
 995 cifs_aio_ctx_alloc(void)
 996 {
 997         struct cifs_aio_ctx *ctx;
 998
 999         /*
1000          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
1001          * to false so that we know when we have to unreference pages within
1002          * cifs_aio_ctx_release()
1003          */
1004         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
1005         if (!ctx)
1006                 return NULL;
1007
1008         INIT_LIST_HEAD(&ctx->list);
1009         mutex_init(&ctx->aio_mutex);
1010         init_completion(&ctx->done);
1011         kref_init(&ctx->refcount);
1012         return ctx;
1013 }
1014
1015 void
1016 cifs_aio_ctx_release(struct kref *refcount)
1017 {
1018         struct cifs_aio_ctx *ctx = container_of(refcount,
1019                                         struct cifs_aio_ctx, refcount);
1020
1021         cifsFileInfo_put(ctx->cfile);
1022
1023         /*
1024          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
1025          * which means that iov_iter_extract_pages() was a success and thus
1026          * that we may have references or pins on pages that we need to
1027          * release.
1028          */
1029         if (ctx->bv) {
1030                 if (ctx->should_dirty || ctx->bv_need_unpin) {
1031                         unsigned int i;
1032
1033                         for (i = 0; i < ctx->nr_pinned_pages; i++) {
1034                                 struct page *page = ctx->bv[i].bv_page;
1035
1036                                 if (ctx->should_dirty)
1037                                         set_page_dirty(page);
1038                                 if (ctx->bv_need_unpin)
1039                                         unpin_user_page(page);
1040                         }
1041                 }
1042                 kvfree(ctx->bv);
1043         }
1044
1045         kfree(ctx);
1046 }
1047
1048 /**
1049  * cifs_alloc_hash - allocate hash and hash context together
1050  * @name: The name of the crypto hash algo
1051  * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1052  *
1053  * The caller has to make sure @sdesc is initialized to either NULL or
1054  * a valid context. It can be freed via cifs_free_hash().
1055  */
1056 int
1057 cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1058 {
1059         int rc = 0;
1060         struct crypto_shash *alg = NULL;
1061
1062         if (*sdesc)
1063                 return 0;
1064
1065         alg = crypto_alloc_shash(name, 0, 0);
1066         if (IS_ERR(alg)) {
1067                 cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1068                 rc = PTR_ERR(alg);
1069                 *sdesc = NULL;
1070                 return rc;
1071         }
1072
1073         *sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1074         if (*sdesc == NULL) {
1075                 cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1076                 crypto_free_shash(alg);
1077                 return -ENOMEM;
1078         }
1079
1080         (*sdesc)->tfm = alg;
1081         return 0;
1082 }
1083
1084 /**
1085  * cifs_free_hash - free hash and hash context together
1086  * @sdesc: Where to find the pointer to the hash TFM
1087  *
1088  * Freeing a NULL descriptor is safe.
1089  */
1090 void
1091 cifs_free_hash(struct shash_desc **sdesc)
1092 {
1093         if (unlikely(!sdesc) || !*sdesc)
1094                 return;
1095
1096         if ((*sdesc)->tfm) {
1097                 crypto_free_shash((*sdesc)->tfm);
1098                 (*sdesc)->tfm = NULL;
1099         }
1100
1101         kfree_sensitive(*sdesc);
1102         *sdesc = NULL;
1103 }
1104
1105 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1106 {
1107         const char *end;
1108
1109         /* skip initial slashes */
1110         while (*unc && (*unc == '\\' || *unc == '/'))
1111                 unc++;
1112
1113         end = unc;
1114
1115         while (*end && !(*end == '\\' || *end == '/'))
1116                 end++;
1117
1118         *h = unc;
1119         *len = end - unc;
1120 }
1121
1122 /**
1123  * copy_path_name - copy src path to dst, possibly truncating
1124  * @dst: The destination buffer
1125  * @src: The source name
1126  *
1127  * returns number of bytes written (including trailing nul)
1128  */
1129 int copy_path_name(char *dst, const char *src)
1130 {
1131         int name_len;
1132
1133         /*
1134          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1135          * will truncate and strlen(dst) will be PATH_MAX-1
1136          */
1137         name_len = strscpy(dst, src, PATH_MAX);
1138         if (WARN_ON_ONCE(name_len < 0))
1139                 name_len = PATH_MAX-1;
1140
1141         /* we count the trailing nul */
1142         name_len++;
1143         return name_len;
1144 }
1145
1146 struct super_cb_data {
1147         void *data;
1148         struct super_block *sb;
1149 };
1150
1151 static void tcon_super_cb(struct super_block *sb, void *arg)
1152 {
1153         struct super_cb_data *sd = arg;
1154         struct cifs_sb_info *cifs_sb;
1155         struct cifs_tcon *t1 = sd->data, *t2;
1156
1157         if (sd->sb)
1158                 return;
1159
1160         cifs_sb = CIFS_SB(sb);
1161         t2 = cifs_sb_master_tcon(cifs_sb);
1162
1163         spin_lock(&t2->tc_lock);
1164         if (t1->ses == t2->ses &&
1165             t1->ses->server == t2->ses->server &&
1166             t2->origin_fullpath &&
1167             dfs_src_pathname_equal(t2->origin_fullpath, t1->origin_fullpath))
1168                 sd->sb = sb;
1169         spin_unlock(&t2->tc_lock);
1170 }
1171
1172 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1173                                             void *data)
1174 {
1175         struct super_cb_data sd = {
1176                 .data = data,
1177                 .sb = NULL,
1178         };
1179         struct file_system_type **fs_type = (struct file_system_type *[]) {
1180                 &cifs_fs_type, &smb3_fs_type, NULL,
1181         };
1182
1183         for (; *fs_type; fs_type++) {
1184                 iterate_supers_type(*fs_type, f, &sd);
1185                 if (sd.sb) {
1186                         /*
1187                          * Grab an active reference in order to prevent automounts (DFS links)
1188                          * of expiring and then freeing up our cifs superblock pointer while
1189                          * we're doing failover.
1190                          */
1191                         cifs_sb_active(sd.sb);
1192                         return sd.sb;
1193                 }
1194         }
1195         pr_warn_once("%s: could not find dfs superblock\n", __func__);
1196         return ERR_PTR(-EINVAL);
1197 }
1198
1199 static void __cifs_put_super(struct super_block *sb)
1200 {
1201         if (!IS_ERR_OR_NULL(sb))
1202                 cifs_sb_deactive(sb);
1203 }
1204
1205 struct super_block *cifs_get_dfs_tcon_super(struct cifs_tcon *tcon)
1206 {
1207         spin_lock(&tcon->tc_lock);
1208         if (!tcon->origin_fullpath) {
1209                 spin_unlock(&tcon->tc_lock);
1210                 return ERR_PTR(-ENOENT);
1211         }
1212         spin_unlock(&tcon->tc_lock);
1213         return __cifs_get_super(tcon_super_cb, tcon);
1214 }
1215
1216 void cifs_put_tcp_super(struct super_block *sb)
1217 {
1218         __cifs_put_super(sb);
1219 }
1220
1221 #ifdef CONFIG_CIFS_DFS_UPCALL
1222 int match_target_ip(struct TCP_Server_Info *server,
1223                     const char *share, size_t share_len,
1224                     bool *result)
1225 {
1226         int rc;
1227         char *target;
1228         struct sockaddr_storage ss;
1229
1230         *result = false;
1231
1232         target = kzalloc(share_len + 3, GFP_KERNEL);
1233         if (!target)
1234                 return -ENOMEM;
1235
1236         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1237
1238         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1239
1240         rc = dns_resolve_server_name_to_ip(target, (struct sockaddr *)&ss, NULL);
1241         kfree(target);
1242
1243         if (rc < 0)
1244                 return rc;
1245
1246         spin_lock(&server->srv_lock);
1247         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
1248         spin_unlock(&server->srv_lock);
1249         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1250         return 0;
1251 }
1252
1253 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1254 {
1255         int rc;
1256
1257         kfree(cifs_sb->prepath);
1258         cifs_sb->prepath = NULL;
1259
1260         if (prefix && *prefix) {
1261                 cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1262                 if (IS_ERR(cifs_sb->prepath)) {
1263                         rc = PTR_ERR(cifs_sb->prepath);
1264                         cifs_sb->prepath = NULL;
1265                         return rc;
1266                 }
1267                 if (cifs_sb->prepath)
1268                         convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1269         }
1270
1271         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1272         return 0;
1273 }
1274
1275 /*
1276  * Handle weird Windows SMB server behaviour. It responds with
1277  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1278  * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1279  * non-ASCII unicode symbols.
1280  */
1281 int cifs_inval_name_dfs_link_error(const unsigned int xid,
1282                                    struct cifs_tcon *tcon,
1283                                    struct cifs_sb_info *cifs_sb,
1284                                    const char *full_path,
1285                                    bool *islink)
1286 {
1287         struct cifs_ses *ses = tcon->ses;
1288         size_t len;
1289         char *path;
1290         char *ref_path;
1291
1292         *islink = false;
1293
1294         /*
1295          * Fast path - skip check when @full_path doesn't have a prefix path to
1296          * look up or tcon is not DFS.
1297          */
1298         if (strlen(full_path) < 2 || !cifs_sb ||
1299             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1300             !is_tcon_dfs(tcon))
1301                 return 0;
1302
1303         spin_lock(&tcon->tc_lock);
1304         if (!tcon->origin_fullpath) {
1305                 spin_unlock(&tcon->tc_lock);
1306                 return 0;
1307         }
1308         spin_unlock(&tcon->tc_lock);
1309
1310         /*
1311          * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1312          * to get a referral to figure out whether it is an DFS link.
1313          */
1314         len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1315         path = kmalloc(len, GFP_KERNEL);
1316         if (!path)
1317                 return -ENOMEM;
1318
1319         scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1320         ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1321                                             cifs_remap(cifs_sb));
1322         kfree(path);
1323
1324         if (IS_ERR(ref_path)) {
1325                 if (PTR_ERR(ref_path) != -EINVAL)
1326                         return PTR_ERR(ref_path);
1327         } else {
1328                 struct dfs_info3_param *refs = NULL;
1329                 int num_refs = 0;
1330
1331                 /*
1332                  * XXX: we are not using dfs_cache_find() here because we might
1333                  * end up filling all the DFS cache and thus potentially
1334                  * removing cached DFS targets that the client would eventually
1335                  * need during failover.
1336                  */
1337                 ses = CIFS_DFS_ROOT_SES(ses);
1338                 if (ses->server->ops->get_dfs_refer &&
1339                     !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1340                                                      &num_refs, cifs_sb->local_nls,
1341                                                      cifs_remap(cifs_sb)))
1342                         *islink = refs[0].server_type == DFS_TYPE_LINK;
1343                 free_dfs_info_array(refs, num_refs);
1344                 kfree(ref_path);
1345         }
1346         return 0;
1347 }
1348 #endif
1349
1350 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1351 {
1352         int timeout = 10;
1353         int rc;
1354
1355         spin_lock(&server->srv_lock);
1356         if (server->tcpStatus != CifsNeedReconnect) {
1357                 spin_unlock(&server->srv_lock);
1358                 return 0;
1359         }
1360         timeout *= server->nr_targets;
1361         spin_unlock(&server->srv_lock);
1362
1363         /*
1364          * Give demultiplex thread up to 10 seconds to each target available for
1365          * reconnect -- should be greater than cifs socket timeout which is 7
1366          * seconds.
1367          *
1368          * On "soft" mounts we wait once. Hard mounts keep retrying until
1369          * process is killed or server comes back on-line.
1370          */
1371         do {
1372                 rc = wait_event_interruptible_timeout(server->response_q,
1373                                                       (server->tcpStatus != CifsNeedReconnect),
1374                                                       timeout * HZ);
1375                 if (rc < 0) {
1376                         cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1377                                  __func__);
1378                         return -ERESTARTSYS;
1379                 }
1380
1381                 /* are we still trying to reconnect? */
1382                 spin_lock(&server->srv_lock);
1383                 if (server->tcpStatus != CifsNeedReconnect) {
1384                         spin_unlock(&server->srv_lock);
1385                         return 0;
1386                 }
1387                 spin_unlock(&server->srv_lock);
1388         } while (retry);
1389
1390         cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1391         return -EHOSTDOWN;
1392 }