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