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 ([email protected])
   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_sensitive(buf_to_free->password2);
 102         kfree(buf_to_free->user_name);
 103         kfree(buf_to_free->domainName);
 104         kfree(buf_to_free->dns_dom);
 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 tcon_info_alloc(bool dir_leases_enabled, enum smb3_tcon_ref_trace trace)
 116 {
 117         struct cifs_tcon *ret_buf;
 118         static atomic_t tcon_debug_id;
 119
 120         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 121         if (!ret_buf)
 122                 return NULL;
 123
 124         if (dir_leases_enabled == true) {
 125                 ret_buf->cfids = init_cached_dirs();
 126                 if (!ret_buf->cfids) {
 127                         kfree(ret_buf);
 128                         return NULL;
 129                 }
 130         }
 131         /* else ret_buf->cfids is already set to NULL above */
 132
 133         atomic_inc(&tconInfoAllocCount);
 134         ret_buf->status = TID_NEW;
 135         ret_buf->debug_id = atomic_inc_return(&tcon_debug_id);
 136         ret_buf->tc_count = 1;
 137         spin_lock_init(&ret_buf->tc_lock);
 138         INIT_LIST_HEAD(&ret_buf->openFileList);
 139         INIT_LIST_HEAD(&ret_buf->tcon_list);
 140         spin_lock_init(&ret_buf->open_file_lock);
 141         spin_lock_init(&ret_buf->stat_lock);
 142         atomic_set(&ret_buf->num_local_opens, 0);
 143         atomic_set(&ret_buf->num_remote_opens, 0);
 144         ret_buf->stats_from_time = ktime_get_real_seconds();
 145 #ifdef CONFIG_CIFS_FSCACHE
 146         mutex_init(&ret_buf->fscache_lock);
 147 #endif
 148         trace_smb3_tcon_ref(ret_buf->debug_id, ret_buf->tc_count, trace);
 149 #ifdef CONFIG_CIFS_DFS_UPCALL
 150         INIT_LIST_HEAD(&ret_buf->dfs_ses_list);
 151 #endif
 152
 153         return ret_buf;
 154 }
 155
 156 void
 157 tconInfoFree(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 158 {
 159         if (tcon == NULL) {
 160                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 161                 return;
 162         }
 163         trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace);
 164         free_cached_dirs(tcon->cfids);
 165         atomic_dec(&tconInfoAllocCount);
 166         kfree(tcon->nativeFileSystem);
 167         kfree_sensitive(tcon->password);
 168         kfree(tcon->origin_fullpath);
 169         kfree(tcon);
 170 }
 171
 172 struct smb_hdr *
 173 cifs_buf_get(void)
 174 {
 175         struct smb_hdr *ret_buf = NULL;
 176         /*
 177          * SMB2 header is bigger than CIFS one - no problems to clean some
 178          * more bytes for CIFS.
 179          */
 180         size_t buf_size = sizeof(struct smb2_hdr);
 181
 182         /*
 183          * We could use negotiated size instead of max_msgsize -
 184          * but it may be more efficient to always alloc same size
 185          * albeit slightly larger than necessary and maxbuffersize
 186          * defaults to this and can not be bigger.
 187          */
 188         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 189
 190         /* clear the first few header bytes */
 191         /* for most paths, more is cleared in header_assemble */
 192         memset(ret_buf, 0, buf_size + 3);
 193         atomic_inc(&buf_alloc_count);
 194 #ifdef CONFIG_CIFS_STATS2
 195         atomic_inc(&total_buf_alloc_count);
 196 #endif /* CONFIG_CIFS_STATS2 */
 197
 198         return ret_buf;
 199 }
 200
 201 void
 202 cifs_buf_release(void *buf_to_free)
 203 {
 204         if (buf_to_free == NULL) {
 205                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 206                 return;
 207         }
 208         mempool_free(buf_to_free, cifs_req_poolp);
 209
 210         atomic_dec(&buf_alloc_count);
 211         return;
 212 }
 213
 214 struct smb_hdr *
 215 cifs_small_buf_get(void)
 216 {
 217         struct smb_hdr *ret_buf = NULL;
 218
 219 /* We could use negotiated size instead of max_msgsize -
 220    but it may be more efficient to always alloc same size
 221    albeit slightly larger than necessary and maxbuffersize
 222    defaults to this and can not be bigger */
 223         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 224         /* No need to clear memory here, cleared in header assemble */
 225         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 226         atomic_inc(&small_buf_alloc_count);
 227 #ifdef CONFIG_CIFS_STATS2
 228         atomic_inc(&total_small_buf_alloc_count);
 229 #endif /* CONFIG_CIFS_STATS2 */
 230
 231         return ret_buf;
 232 }
 233
 234 void
 235 cifs_small_buf_release(void *buf_to_free)
 236 {
 237
 238         if (buf_to_free == NULL) {
 239                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 240                 return;
 241         }
 242         mempool_free(buf_to_free, cifs_sm_req_poolp);
 243
 244         atomic_dec(&small_buf_alloc_count);
 245         return;
 246 }
 247
 248 void
 249 free_rsp_buf(int resp_buftype, void *rsp)
 250 {
 251         if (resp_buftype == CIFS_SMALL_BUFFER)
 252                 cifs_small_buf_release(rsp);
 253         else if (resp_buftype == CIFS_LARGE_BUFFER)
 254                 cifs_buf_release(rsp);
 255 }
 256
 257 /* NB: MID can not be set if treeCon not passed in, in that
 258    case it is responsibility of caller to set the mid */
 259 void
 260 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 261                 const struct cifs_tcon *treeCon, int word_count
 262                 /* length of fixed section (word count) in two byte units  */)
 263 {
 264         char *temp = (char *) buffer;
 265
 266         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 267
 268         buffer->smb_buf_length = cpu_to_be32(
 269             (2 * word_count) + sizeof(struct smb_hdr) -
 270             4 /*  RFC 1001 length field does not count */  +
 271             2 /* for bcc field itself */) ;
 272
 273         buffer->Protocol[0] = 0xFF;
 274         buffer->Protocol[1] = 'S';
 275         buffer->Protocol[2] = 'M';
 276         buffer->Protocol[3] = 'B';
 277         buffer->Command = smb_command;
 278         buffer->Flags = 0x00;   /* case sensitive */
 279         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 280         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 281         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 282         if (treeCon) {
 283                 buffer->Tid = treeCon->tid;
 284                 if (treeCon->ses) {
 285                         if (treeCon->ses->capabilities & CAP_UNICODE)
 286                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 287                         if (treeCon->ses->capabilities & CAP_STATUS32)
 288                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 289
 290                         /* Uid is not converted */
 291                         buffer->Uid = treeCon->ses->Suid;
 292                         if (treeCon->ses->server)
 293                                 buffer->Mid = get_next_mid(treeCon->ses->server);
 294                 }
 295                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 296                         buffer->Flags2 |= SMBFLG2_DFS;
 297                 if (treeCon->nocase)
 298                         buffer->Flags  |= SMBFLG_CASELESS;
 299                 if ((treeCon->ses) && (treeCon->ses->server))
 300                         if (treeCon->ses->server->sign)
 301                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 302         }
 303
 304 /*  endian conversion of flags is now done just before sending */
 305         buffer->WordCount = (char) word_count;
 306         return;
 307 }
 308
 309 static int
 310 check_smb_hdr(struct smb_hdr *smb)
 311 {
 312         /* does it have the right SMB "signature" ? */
 313         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 314                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 315                          *(unsigned int *)smb->Protocol);
 316                 return 1;
 317         }
 318
 319         /* if it's a response then accept */
 320         if (smb->Flags & SMBFLG_RESPONSE)
 321                 return 0;
 322
 323         /* only one valid case where server sends us request */
 324         if (smb->Command == SMB_COM_LOCKING_ANDX)
 325                 return 0;
 326
 327         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 328                  get_mid(smb));
 329         return 1;
 330 }
 331
 332 int
 333 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 334 {
 335         struct smb_hdr *smb = (struct smb_hdr *)buf;
 336         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 337         __u32 clc_len;  /* calculated length */
 338         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 339                  total_read, rfclen);
 340
 341         /* is this frame too small to even get to a BCC? */
 342         if (total_read < 2 + sizeof(struct smb_hdr)) {
 343                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 344                             && (smb->Status.CifsError != 0)) {
 345                         /* it's an error return */
 346                         smb->WordCount = 0;
 347                         /* some error cases do not return wct and bcc */
 348                         return 0;
 349                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 350                                 (smb->WordCount == 0)) {
 351                         char *tmp = (char *)smb;
 352                         /* Need to work around a bug in two servers here */
 353                         /* First, check if the part of bcc they sent was zero */
 354                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 355                                 /* some servers return only half of bcc
 356                                  * on simple responses (wct, bcc both zero)
 357                                  * in particular have seen this on
 358                                  * ulogoffX and FindClose. This leaves
 359                                  * one byte of bcc potentially uninitialized
 360                                  */
 361                                 /* zero rest of bcc */
 362                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 363                                 return 0;
 364                         }
 365                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 366                 } else {
 367                         cifs_dbg(VFS, "Length less than smb header size\n");
 368                 }
 369                 return -EIO;
 370         } else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
 371                 cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
 372                          __func__, smb->WordCount);
 373                 return -EIO;
 374         }
 375
 376         /* otherwise, there is enough to get to the BCC */
 377         if (check_smb_hdr(smb))
 378                 return -EIO;
 379         clc_len = smbCalcSize(smb);
 380
 381         if (4 + rfclen != total_read) {
 382                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 383                          rfclen);
 384                 return -EIO;
 385         }
 386
 387         if (4 + rfclen != clc_len) {
 388                 __u16 mid = get_mid(smb);
 389                 /* check if bcc wrapped around for large read responses */
 390                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 391                         /* check if lengths match mod 64K */
 392                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 393                                 return 0; /* bcc wrapped */
 394                 }
 395                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 396                          clc_len, 4 + rfclen, mid);
 397
 398                 if (4 + rfclen < clc_len) {
 399                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 400                                  rfclen, mid);
 401                         return -EIO;
 402                 } else if (rfclen > clc_len + 512) {
 403                         /*
 404                          * Some servers (Windows XP in particular) send more
 405                          * data than the lengths in the SMB packet would
 406                          * indicate on certain calls (byte range locks and
 407                          * trans2 find first calls in particular). While the
 408                          * client can handle such a frame by ignoring the
 409                          * trailing data, we choose limit the amount of extra
 410                          * data to 512 bytes.
 411                          */
 412                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 413                                  rfclen, mid);
 414                         return -EIO;
 415                 }
 416         }
 417         return 0;
 418 }
 419
 420 bool
 421 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 422 {
 423         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 424         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 425         struct TCP_Server_Info *pserver;
 426         struct cifs_ses *ses;
 427         struct cifs_tcon *tcon;
 428         struct cifsInodeInfo *pCifsInode;
 429         struct cifsFileInfo *netfile;
 430
 431         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 432         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 433            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 434                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 435                         (struct smb_com_transaction_change_notify_rsp *)buf;
 436                 struct file_notify_information *pnotify;
 437                 __u32 data_offset = 0;
 438                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 439
 440                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 441                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 442
 443                         if (data_offset >
 444                             len - sizeof(struct file_notify_information)) {
 445                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
 446                                          data_offset);
 447                                 return true;
 448                         }
 449                         pnotify = (struct file_notify_information *)
 450                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 451                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 452                                  pnotify->FileName, pnotify->Action);
 453                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 454                                 sizeof(struct smb_hdr)+60); */
 455                         return true;
 456                 }
 457                 if (pSMBr->hdr.Status.CifsError) {
 458                         cifs_dbg(FYI, "notify err 0x%x\n",
 459                                  pSMBr->hdr.Status.CifsError);
 460                         return true;
 461                 }
 462                 return false;
 463         }
 464         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 465                 return false;
 466         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 467                 /* no sense logging error on invalid handle on oplock
 468                    break - harmless race between close request and oplock
 469                    break response is expected from time to time writing out
 470                    large dirty files cached on the client */
 471                 if ((NT_STATUS_INVALID_HANDLE) ==
 472                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 473                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
 474                         return true;
 475                 } else if (ERRbadfid ==
 476                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 477                         return true;
 478                 } else {
 479                         return false; /* on valid oplock brk we get "request" */
 480                 }
 481         }
 482         if (pSMB->hdr.WordCount != 8)
 483                 return false;
 484
 485         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 486                  pSMB->LockType, pSMB->OplockLevel);
 487         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 488                 return false;
 489
 490         /* If server is a channel, select the primary channel */
 491         pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
 492
 493         /* look up tcon based on tid & uid */
 494         spin_lock(&cifs_tcp_ses_lock);
 495         list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 496                 if (cifs_ses_exiting(ses))
 497                         continue;
 498                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 499                         if (tcon->tid != buf->Tid)
 500                                 continue;
 501
 502                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 503                         spin_lock(&tcon->open_file_lock);
 504                         list_for_each_entry(netfile, &tcon->openFileList, tlist) {
 505                                 if (pSMB->Fid != netfile->fid.netfid)
 506                                         continue;
 507
 508                                 cifs_dbg(FYI, "file id match, oplock break\n");
 509                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 510
 511                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 512                                         &pCifsInode->flags);
 513
 514                                 netfile->oplock_epoch = 0;
 515                                 netfile->oplock_level = pSMB->OplockLevel;
 516                                 netfile->oplock_break_cancelled = false;
 517                                 cifs_queue_oplock_break(netfile);
 518
 519                                 spin_unlock(&tcon->open_file_lock);
 520                                 spin_unlock(&cifs_tcp_ses_lock);
 521                                 return true;
 522                         }
 523                         spin_unlock(&tcon->open_file_lock);
 524                         spin_unlock(&cifs_tcp_ses_lock);
 525                         cifs_dbg(FYI, "No matching file for oplock break\n");
 526                         return true;
 527                 }
 528         }
 529         spin_unlock(&cifs_tcp_ses_lock);
 530         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 531         return true;
 532 }
 533
 534 void
 535 dump_smb(void *buf, int smb_buf_length)
 536 {
 537         if (traceSMB == 0)
 538                 return;
 539
 540         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 541                        smb_buf_length, true);
 542 }
 543
 544 void
 545 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 546 {
 547         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 548                 struct cifs_tcon *tcon = NULL;
 549
 550                 if (cifs_sb->master_tlink)
 551                         tcon = cifs_sb_master_tcon(cifs_sb);
 552
 553                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 554                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 555                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 556                          tcon ? tcon->tree_name : "new server");
 557                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 558                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 559
 560         }
 561 }
 562
 563 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 564 {
 565         oplock &= 0xF;
 566
 567         if (oplock == OPLOCK_EXCLUSIVE) {
 568                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 569                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 570                          &cinode->netfs.inode);
 571         } else if (oplock == OPLOCK_READ) {
 572                 cinode->oplock = CIFS_CACHE_READ_FLG;
 573                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 574                          &cinode->netfs.inode);
 575         } else
 576                 cinode->oplock = 0;
 577 }
 578
 579 /*
 580  * We wait for oplock breaks to be processed before we attempt to perform
 581  * writes.
 582  */
 583 int cifs_get_writer(struct cifsInodeInfo *cinode)
 584 {
 585         int rc;
 586
 587 start:
 588         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 589                          TASK_KILLABLE);
 590         if (rc)
 591                 return rc;
 592
 593         spin_lock(&cinode->writers_lock);
 594         if (!cinode->writers)
 595                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 596         cinode->writers++;
 597         /* Check to see if we have started servicing an oplock break */
 598         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 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                 goto start;
 606         }
 607         spin_unlock(&cinode->writers_lock);
 608         return 0;
 609 }
 610
 611 void cifs_put_writer(struct cifsInodeInfo *cinode)
 612 {
 613         spin_lock(&cinode->writers_lock);
 614         cinode->writers--;
 615         if (cinode->writers == 0) {
 616                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 617                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 618         }
 619         spin_unlock(&cinode->writers_lock);
 620 }
 621
 622 /**
 623  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 624  * @cfile: The file to break the oplock on
 625  *
 626  * This function is called from the demultiplex thread when it
 627  * receives an oplock break for @cfile.
 628  *
 629  * Assumes the tcon->open_file_lock is held.
 630  * Assumes cfile->file_info_lock is NOT held.
 631  */
 632 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 633 {
 634         /*
 635          * Bump the handle refcount now while we hold the
 636          * open_file_lock to enforce the validity of it for the oplock
 637          * break handler. The matching put is done at the end of the
 638          * handler.
 639          */
 640         cifsFileInfo_get(cfile);
 641
 642         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 643 }
 644
 645 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 646 {
 647         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 648         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 649 }
 650
 651 bool
 652 backup_cred(struct cifs_sb_info *cifs_sb)
 653 {
 654         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 655                 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
 656                         return true;
 657         }
 658         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 659                 if (in_group_p(cifs_sb->ctx->backupgid))
 660                         return true;
 661         }
 662
 663         return false;
 664 }
 665
 666 void
 667 cifs_del_pending_open(struct cifs_pending_open *open)
 668 {
 669         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 670         list_del(&open->olist);
 671         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 672 }
 673
 674 void
 675 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 676                              struct cifs_pending_open *open)
 677 {
 678         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 679         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 680         open->tlink = tlink;
 681         fid->pending_open = open;
 682         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 683 }
 684
 685 void
 686 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 687                       struct cifs_pending_open *open)
 688 {
 689         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 690         cifs_add_pending_open_locked(fid, tlink, open);
 691         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 692 }
 693
 694 /*
 695  * Critical section which runs after acquiring deferred_lock.
 696  * As there is no reference count on cifs_deferred_close, pdclose
 697  * should not be used outside deferred_lock.
 698  */
 699 bool
 700 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
 701 {
 702         struct cifs_deferred_close *dclose;
 703
 704         list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
 705                 if ((dclose->netfid == cfile->fid.netfid) &&
 706                         (dclose->persistent_fid == cfile->fid.persistent_fid) &&
 707                         (dclose->volatile_fid == cfile->fid.volatile_fid)) {
 708                         *pdclose = dclose;
 709                         return true;
 710                 }
 711         }
 712         return false;
 713 }
 714
 715 /*
 716  * Critical section which runs after acquiring deferred_lock.
 717  */
 718 void
 719 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
 720 {
 721         bool is_deferred = false;
 722         struct cifs_deferred_close *pdclose;
 723
 724         is_deferred = cifs_is_deferred_close(cfile, &pdclose);
 725         if (is_deferred) {
 726                 kfree(dclose);
 727                 return;
 728         }
 729
 730         dclose->tlink = cfile->tlink;
 731         dclose->netfid = cfile->fid.netfid;
 732         dclose->persistent_fid = cfile->fid.persistent_fid;
 733         dclose->volatile_fid = cfile->fid.volatile_fid;
 734         list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
 735 }
 736
 737 /*
 738  * Critical section which runs after acquiring deferred_lock.
 739  */
 740 void
 741 cifs_del_deferred_close(struct cifsFileInfo *cfile)
 742 {
 743         bool is_deferred = false;
 744         struct cifs_deferred_close *dclose;
 745
 746         is_deferred = cifs_is_deferred_close(cfile, &dclose);
 747         if (!is_deferred)
 748                 return;
 749         list_del(&dclose->dlist);
 750         kfree(dclose);
 751 }
 752
 753 void
 754 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
 755 {
 756         struct cifsFileInfo *cfile = NULL;
 757         struct file_list *tmp_list, *tmp_next_list;
 758         LIST_HEAD(file_head);
 759
 760         if (cifs_inode == NULL)
 761                 return;
 762
 763         spin_lock(&cifs_inode->open_file_lock);
 764         list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
 765                 if (delayed_work_pending(&cfile->deferred)) {
 766                         if (cancel_delayed_work(&cfile->deferred)) {
 767                                 spin_lock(&cifs_inode->deferred_lock);
 768                                 cifs_del_deferred_close(cfile);
 769                                 spin_unlock(&cifs_inode->deferred_lock);
 770
 771                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 772                                 if (tmp_list == NULL)
 773                                         break;
 774                                 tmp_list->cfile = cfile;
 775                                 list_add_tail(&tmp_list->list, &file_head);
 776                         }
 777                 }
 778         }
 779         spin_unlock(&cifs_inode->open_file_lock);
 780
 781         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 782                 _cifsFileInfo_put(tmp_list->cfile, false, false);
 783                 list_del(&tmp_list->list);
 784                 kfree(tmp_list);
 785         }
 786 }
 787
 788 void
 789 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 790 {
 791         struct cifsFileInfo *cfile;
 792         struct file_list *tmp_list, *tmp_next_list;
 793         LIST_HEAD(file_head);
 794
 795         spin_lock(&tcon->open_file_lock);
 796         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 797                 if (delayed_work_pending(&cfile->deferred)) {
 798                         if (cancel_delayed_work(&cfile->deferred)) {
 799                                 spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 800                                 cifs_del_deferred_close(cfile);
 801                                 spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 802
 803                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 804                                 if (tmp_list == NULL)
 805                                         break;
 806                                 tmp_list->cfile = cfile;
 807                                 list_add_tail(&tmp_list->list, &file_head);
 808                         }
 809                 }
 810         }
 811         spin_unlock(&tcon->open_file_lock);
 812
 813         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 814                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 815                 list_del(&tmp_list->list);
 816                 kfree(tmp_list);
 817         }
 818 }
 819 void
 820 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
 821 {
 822         struct cifsFileInfo *cfile;
 823         struct file_list *tmp_list, *tmp_next_list;
 824         void *page;
 825         const char *full_path;
 826         LIST_HEAD(file_head);
 827
 828         page = alloc_dentry_path();
 829         spin_lock(&tcon->open_file_lock);
 830         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 831                 full_path = build_path_from_dentry(cfile->dentry, page);
 832                 if (strstr(full_path, path)) {
 833                         if (delayed_work_pending(&cfile->deferred)) {
 834                                 if (cancel_delayed_work(&cfile->deferred)) {
 835                                         spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 836                                         cifs_del_deferred_close(cfile);
 837                                         spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 838
 839                                         tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 840                                         if (tmp_list == NULL)
 841                                                 break;
 842                                         tmp_list->cfile = cfile;
 843                                         list_add_tail(&tmp_list->list, &file_head);
 844                                 }
 845                         }
 846                 }
 847         }
 848         spin_unlock(&tcon->open_file_lock);
 849
 850         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 851                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 852                 list_del(&tmp_list->list);
 853                 kfree(tmp_list);
 854         }
 855         free_dentry_path(page);
 856 }
 857
 858 /*
 859  * If a dentry has been deleted, all corresponding open handles should know that
 860  * so that we do not defer close them.
 861  */
 862 void cifs_mark_open_handles_for_deleted_file(struct inode *inode,
 863                                              const char *path)
 864 {
 865         struct cifsFileInfo *cfile;
 866         void *page;
 867         const char *full_path;
 868         struct cifsInodeInfo *cinode = CIFS_I(inode);
 869
 870         page = alloc_dentry_path();
 871         spin_lock(&cinode->open_file_lock);
 872
 873         /*
 874          * note: we need to construct path from dentry and compare only if the
 875          * inode has any hardlinks. When number of hardlinks is 1, we can just
 876          * mark all open handles since they are going to be from the same file.
 877          */
 878         if (inode->i_nlink > 1) {
 879                 list_for_each_entry(cfile, &cinode->openFileList, flist) {
 880                         full_path = build_path_from_dentry(cfile->dentry, page);
 881                         if (!IS_ERR(full_path) && strcmp(full_path, path) == 0)
 882                                 cfile->status_file_deleted = true;
 883                 }
 884         } else {
 885                 list_for_each_entry(cfile, &cinode->openFileList, flist)
 886                         cfile->status_file_deleted = true;
 887         }
 888         spin_unlock(&cinode->open_file_lock);
 889         free_dentry_path(page);
 890 }
 891
 892 /* parses DFS referral V3 structure
 893  * caller is responsible for freeing target_nodes
 894  * returns:
 895  * - on success - 0
 896  * - on failure - errno
 897  */
 898 int
 899 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 900                     unsigned int *num_of_nodes,
 901                     struct dfs_info3_param **target_nodes,
 902                     const struct nls_table *nls_codepage, int remap,
 903                     const char *searchName, bool is_unicode)
 904 {
 905         int i, rc = 0;
 906         char *data_end;
 907         struct dfs_referral_level_3 *ref;
 908
 909         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 910
 911         if (*num_of_nodes < 1) {
 912                 cifs_dbg(VFS | ONCE, "%s: [path=%s] num_referrals must be at least > 0, but we got %d\n",
 913                          __func__, searchName, *num_of_nodes);
 914                 rc = -ENOENT;
 915                 goto parse_DFS_referrals_exit;
 916         }
 917
 918         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 919         if (ref->VersionNumber != cpu_to_le16(3)) {
 920                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 921                          le16_to_cpu(ref->VersionNumber));
 922                 rc = -EINVAL;
 923                 goto parse_DFS_referrals_exit;
 924         }
 925
 926         /* get the upper boundary of the resp buffer */
 927         data_end = (char *)rsp + rsp_size;
 928
 929         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 930                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 931
 932         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 933                                 GFP_KERNEL);
 934         if (*target_nodes == NULL) {
 935                 rc = -ENOMEM;
 936                 goto parse_DFS_referrals_exit;
 937         }
 938
 939         /* collect necessary data from referrals */
 940         for (i = 0; i < *num_of_nodes; i++) {
 941                 char *temp;
 942                 int max_len;
 943                 struct dfs_info3_param *node = (*target_nodes)+i;
 944
 945                 node->flags = le32_to_cpu(rsp->DFSFlags);
 946                 if (is_unicode) {
 947                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 948                                                 GFP_KERNEL);
 949                         if (tmp == NULL) {
 950                                 rc = -ENOMEM;
 951                                 goto parse_DFS_referrals_exit;
 952                         }
 953                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 954                                            PATH_MAX, nls_codepage, remap);
 955                         node->path_consumed = cifs_utf16_bytes(tmp,
 956                                         le16_to_cpu(rsp->PathConsumed),
 957                                         nls_codepage);
 958                         kfree(tmp);
 959                 } else
 960                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 961
 962                 node->server_type = le16_to_cpu(ref->ServerType);
 963                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 964
 965                 /* copy DfsPath */
 966                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 967                 max_len = data_end - temp;
 968                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 969                                                 is_unicode, nls_codepage);
 970                 if (!node->path_name) {
 971                         rc = -ENOMEM;
 972                         goto parse_DFS_referrals_exit;
 973                 }
 974
 975                 /* copy link target UNC */
 976                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 977                 max_len = data_end - temp;
 978                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 979                                                 is_unicode, nls_codepage);
 980                 if (!node->node_name) {
 981                         rc = -ENOMEM;
 982                         goto parse_DFS_referrals_exit;
 983                 }
 984
 985                 node->ttl = le32_to_cpu(ref->TimeToLive);
 986
 987                 ref++;
 988         }
 989
 990 parse_DFS_referrals_exit:
 991         if (rc) {
 992                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 993                 *target_nodes = NULL;
 994                 *num_of_nodes = 0;
 995         }
 996         return rc;
 997 }
 998
 999 /**
1000  * cifs_alloc_hash - allocate hash and hash context together
1001  * @name: The name of the crypto hash algo
1002  * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1003  *
1004  * The caller has to make sure @sdesc is initialized to either NULL or
1005  * a valid context. It can be freed via cifs_free_hash().
1006  */
1007 int
1008 cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1009 {
1010         int rc = 0;
1011         struct crypto_shash *alg = NULL;
1012
1013         if (*sdesc)
1014                 return 0;
1015
1016         alg = crypto_alloc_shash(name, 0, 0);
1017         if (IS_ERR(alg)) {
1018                 cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1019                 rc = PTR_ERR(alg);
1020                 *sdesc = NULL;
1021                 return rc;
1022         }
1023
1024         *sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1025         if (*sdesc == NULL) {
1026                 cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1027                 crypto_free_shash(alg);
1028                 return -ENOMEM;
1029         }
1030
1031         (*sdesc)->tfm = alg;
1032         return 0;
1033 }
1034
1035 /**
1036  * cifs_free_hash - free hash and hash context together
1037  * @sdesc: Where to find the pointer to the hash TFM
1038  *
1039  * Freeing a NULL descriptor is safe.
1040  */
1041 void
1042 cifs_free_hash(struct shash_desc **sdesc)
1043 {
1044         if (unlikely(!sdesc) || !*sdesc)
1045                 return;
1046
1047         if ((*sdesc)->tfm) {
1048                 crypto_free_shash((*sdesc)->tfm);
1049                 (*sdesc)->tfm = NULL;
1050         }
1051
1052         kfree_sensitive(*sdesc);
1053         *sdesc = NULL;
1054 }
1055
1056 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1057 {
1058         const char *end;
1059
1060         /* skip initial slashes */
1061         while (*unc && (*unc == '\\' || *unc == '/'))
1062                 unc++;
1063
1064         end = unc;
1065
1066         while (*end && !(*end == '\\' || *end == '/'))
1067                 end++;
1068
1069         *h = unc;
1070         *len = end - unc;
1071 }
1072
1073 /**
1074  * copy_path_name - copy src path to dst, possibly truncating
1075  * @dst: The destination buffer
1076  * @src: The source name
1077  *
1078  * returns number of bytes written (including trailing nul)
1079  */
1080 int copy_path_name(char *dst, const char *src)
1081 {
1082         int name_len;
1083
1084         /*
1085          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1086          * will truncate and strlen(dst) will be PATH_MAX-1
1087          */
1088         name_len = strscpy(dst, src, PATH_MAX);
1089         if (WARN_ON_ONCE(name_len < 0))
1090                 name_len = PATH_MAX-1;
1091
1092         /* we count the trailing nul */
1093         name_len++;
1094         return name_len;
1095 }
1096
1097 struct super_cb_data {
1098         void *data;
1099         struct super_block *sb;
1100 };
1101
1102 static void tcon_super_cb(struct super_block *sb, void *arg)
1103 {
1104         struct super_cb_data *sd = arg;
1105         struct cifs_sb_info *cifs_sb;
1106         struct cifs_tcon *t1 = sd->data, *t2;
1107
1108         if (sd->sb)
1109                 return;
1110
1111         cifs_sb = CIFS_SB(sb);
1112         t2 = cifs_sb_master_tcon(cifs_sb);
1113
1114         spin_lock(&t2->tc_lock);
1115         if ((t1->ses == t2->ses ||
1116              t1->ses->dfs_root_ses == t2->ses->dfs_root_ses) &&
1117             t1->ses->server == t2->ses->server &&
1118             t2->origin_fullpath &&
1119             dfs_src_pathname_equal(t2->origin_fullpath, t1->origin_fullpath))
1120                 sd->sb = sb;
1121         spin_unlock(&t2->tc_lock);
1122 }
1123
1124 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1125                                             void *data)
1126 {
1127         struct super_cb_data sd = {
1128                 .data = data,
1129                 .sb = NULL,
1130         };
1131         struct file_system_type **fs_type = (struct file_system_type *[]) {
1132                 &cifs_fs_type, &smb3_fs_type, NULL,
1133         };
1134
1135         for (; *fs_type; fs_type++) {
1136                 iterate_supers_type(*fs_type, f, &sd);
1137                 if (sd.sb) {
1138                         /*
1139                          * Grab an active reference in order to prevent automounts (DFS links)
1140                          * of expiring and then freeing up our cifs superblock pointer while
1141                          * we're doing failover.
1142                          */
1143                         cifs_sb_active(sd.sb);
1144                         return sd.sb;
1145                 }
1146         }
1147         pr_warn_once("%s: could not find dfs superblock\n", __func__);
1148         return ERR_PTR(-EINVAL);
1149 }
1150
1151 static void __cifs_put_super(struct super_block *sb)
1152 {
1153         if (!IS_ERR_OR_NULL(sb))
1154                 cifs_sb_deactive(sb);
1155 }
1156
1157 struct super_block *cifs_get_dfs_tcon_super(struct cifs_tcon *tcon)
1158 {
1159         spin_lock(&tcon->tc_lock);
1160         if (!tcon->origin_fullpath) {
1161                 spin_unlock(&tcon->tc_lock);
1162                 return ERR_PTR(-ENOENT);
1163         }
1164         spin_unlock(&tcon->tc_lock);
1165         return __cifs_get_super(tcon_super_cb, tcon);
1166 }
1167
1168 void cifs_put_tcp_super(struct super_block *sb)
1169 {
1170         __cifs_put_super(sb);
1171 }
1172
1173 #ifdef CONFIG_CIFS_DFS_UPCALL
1174 int match_target_ip(struct TCP_Server_Info *server,
1175                     const char *host, size_t hostlen,
1176                     bool *result)
1177 {
1178         struct sockaddr_storage ss;
1179         int rc;
1180
1181         cifs_dbg(FYI, "%s: hostname=%.*s\n", __func__, (int)hostlen, host);
1182
1183         *result = false;
1184
1185         rc = dns_resolve_name(server->dns_dom, host, hostlen,
1186                               (struct sockaddr *)&ss);
1187         if (rc < 0)
1188                 return rc;
1189
1190         spin_lock(&server->srv_lock);
1191         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
1192         spin_unlock(&server->srv_lock);
1193         cifs_dbg(FYI, "%s: ip addresses matched: %s\n", __func__, str_yes_no(*result));
1194         return 0;
1195 }
1196
1197 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1198 {
1199         int rc;
1200
1201         kfree(cifs_sb->prepath);
1202         cifs_sb->prepath = NULL;
1203
1204         if (prefix && *prefix) {
1205                 cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1206                 if (IS_ERR(cifs_sb->prepath)) {
1207                         rc = PTR_ERR(cifs_sb->prepath);
1208                         cifs_sb->prepath = NULL;
1209                         return rc;
1210                 }
1211                 if (cifs_sb->prepath)
1212                         convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1213         }
1214
1215         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1216         return 0;
1217 }
1218
1219 /*
1220  * Handle weird Windows SMB server behaviour. It responds with
1221  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1222  * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1223  * non-ASCII unicode symbols.
1224  */
1225 int cifs_inval_name_dfs_link_error(const unsigned int xid,
1226                                    struct cifs_tcon *tcon,
1227                                    struct cifs_sb_info *cifs_sb,
1228                                    const char *full_path,
1229                                    bool *islink)
1230 {
1231         struct TCP_Server_Info *server = tcon->ses->server;
1232         struct cifs_ses *ses = tcon->ses;
1233         size_t len;
1234         char *path;
1235         char *ref_path;
1236
1237         *islink = false;
1238
1239         /*
1240          * Fast path - skip check when @full_path doesn't have a prefix path to
1241          * look up or tcon is not DFS.
1242          */
1243         if (strlen(full_path) < 2 || !cifs_sb ||
1244             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1245             !is_tcon_dfs(tcon))
1246                 return 0;
1247
1248         spin_lock(&server->srv_lock);
1249         if (!server->leaf_fullpath) {
1250                 spin_unlock(&server->srv_lock);
1251                 return 0;
1252         }
1253         spin_unlock(&server->srv_lock);
1254
1255         /*
1256          * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1257          * to get a referral to figure out whether it is an DFS link.
1258          */
1259         len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1260         path = kmalloc(len, GFP_KERNEL);
1261         if (!path)
1262                 return -ENOMEM;
1263
1264         scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1265         ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1266                                             cifs_remap(cifs_sb));
1267         kfree(path);
1268
1269         if (IS_ERR(ref_path)) {
1270                 if (PTR_ERR(ref_path) != -EINVAL)
1271                         return PTR_ERR(ref_path);
1272         } else {
1273                 struct dfs_info3_param *refs = NULL;
1274                 int num_refs = 0;
1275
1276                 /*
1277                  * XXX: we are not using dfs_cache_find() here because we might
1278                  * end up filling all the DFS cache and thus potentially
1279                  * removing cached DFS targets that the client would eventually
1280                  * need during failover.
1281                  */
1282                 ses = CIFS_DFS_ROOT_SES(ses);
1283                 if (ses->server->ops->get_dfs_refer &&
1284                     !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1285                                                      &num_refs, cifs_sb->local_nls,
1286                                                      cifs_remap(cifs_sb)))
1287                         *islink = refs[0].server_type == DFS_TYPE_LINK;
1288                 free_dfs_info_array(refs, num_refs);
1289                 kfree(ref_path);
1290         }
1291         return 0;
1292 }
1293 #endif
1294
1295 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1296 {
1297         int timeout = 10;
1298         int rc;
1299
1300         spin_lock(&server->srv_lock);
1301         if (server->tcpStatus != CifsNeedReconnect) {
1302                 spin_unlock(&server->srv_lock);
1303                 return 0;
1304         }
1305         timeout *= server->nr_targets;
1306         spin_unlock(&server->srv_lock);
1307
1308         /*
1309          * Give demultiplex thread up to 10 seconds to each target available for
1310          * reconnect -- should be greater than cifs socket timeout which is 7
1311          * seconds.
1312          *
1313          * On "soft" mounts we wait once. Hard mounts keep retrying until
1314          * process is killed or server comes back on-line.
1315          */
1316         do {
1317                 rc = wait_event_interruptible_timeout(server->response_q,
1318                                                       (server->tcpStatus != CifsNeedReconnect),
1319                                                       timeout * HZ);
1320                 if (rc < 0) {
1321                         cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1322                                  __func__);
1323                         return -ERESTARTSYS;
1324                 }
1325
1326                 /* are we still trying to reconnect? */
1327                 spin_lock(&server->srv_lock);
1328                 if (server->tcpStatus != CifsNeedReconnect) {
1329                         spin_unlock(&server->srv_lock);
1330                         return 0;
1331                 }
1332                 spin_unlock(&server->srv_lock);
1333         } while (retry);
1334
1335         cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1336         return -EHOSTDOWN;
1337 }