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