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