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