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