fs/smb/client/misc.c

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