fs/smb/client/misc.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  */
   8
   9 #include <linux/slab.h>
  10 #include <linux/ctype.h>
  11 #include <linux/mempool.h>
  12 #include <linux/vmalloc.h>
  13 #include "cifspdu.h"
  14 #include "cifsglob.h"
  15 #include "cifsproto.h"
  16 #include "cifs_debug.h"
  17 #include "smberr.h"
  18 #include "nterr.h"
  19 #include "cifs_unicode.h"
  20 #include "smb2pdu.h"
  21 #include "cifsfs.h"
  22 #ifdef CONFIG_CIFS_DFS_UPCALL
  23 #include "dns_resolve.h"
  24 #include "dfs_cache.h"
  25 #include "dfs.h"
  26 #endif
  27 #include "fs_context.h"
  28 #include "cached_dir.h"
  29
  30 /* The xid serves as a useful identifier for each incoming vfs request,
  31    in a similar way to the mid which is useful to track each sent smb,
  32    and CurrentXid can also provide a running counter (although it
  33    will eventually wrap past zero) of the total vfs operations handled
  34    since the cifs fs was mounted */
  35
  36 unsigned int
  37 _get_xid(void)
  38 {
  39         unsigned int xid;
  40
  41         spin_lock(&GlobalMid_Lock);
  42         GlobalTotalActiveXid++;
  43
  44         /* keep high water mark for number of simultaneous ops in filesystem */
  45         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  46                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  47         if (GlobalTotalActiveXid > 65000)
  48                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  49         xid = GlobalCurrentXid++;
  50         spin_unlock(&GlobalMid_Lock);
  51         return xid;
  52 }
  53
  54 void
  55 _free_xid(unsigned int xid)
  56 {
  57         spin_lock(&GlobalMid_Lock);
  58         /* if (GlobalTotalActiveXid == 0)
  59                 BUG(); */
  60         GlobalTotalActiveXid--;
  61         spin_unlock(&GlobalMid_Lock);
  62 }
  63
  64 struct cifs_ses *
  65 sesInfoAlloc(void)
  66 {
  67         struct cifs_ses *ret_buf;
  68
  69         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  70         if (ret_buf) {
  71                 atomic_inc(&sesInfoAllocCount);
  72                 spin_lock_init(&ret_buf->ses_lock);
  73                 ret_buf->ses_status = SES_NEW;
  74                 ++ret_buf->ses_count;
  75                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  76                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  77                 mutex_init(&ret_buf->session_mutex);
  78                 spin_lock_init(&ret_buf->iface_lock);
  79                 INIT_LIST_HEAD(&ret_buf->iface_list);
  80                 spin_lock_init(&ret_buf->chan_lock);
  81         }
  82         return ret_buf;
  83 }
  84
  85 void
  86 sesInfoFree(struct cifs_ses *buf_to_free)
  87 {
  88         struct cifs_server_iface *iface = NULL, *niface = NULL;
  89
  90         if (buf_to_free == NULL) {
  91                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  92                 return;
  93         }
  94
  95         unload_nls(buf_to_free->local_nls);
  96         atomic_dec(&sesInfoAllocCount);
  97         kfree(buf_to_free->serverOS);
  98         kfree(buf_to_free->serverDomain);
  99         kfree(buf_to_free->serverNOS);
 100         kfree_sensitive(buf_to_free->password);
 101         kfree_sensitive(buf_to_free->password2);
 102         kfree(buf_to_free->user_name);
 103         kfree(buf_to_free->domainName);
 104         kfree_sensitive(buf_to_free->auth_key.response);
 105         spin_lock(&buf_to_free->iface_lock);
 106         list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
 107                                  iface_head)
 108                 kref_put(&iface->refcount, release_iface);
 109         spin_unlock(&buf_to_free->iface_lock);
 110         kfree_sensitive(buf_to_free);
 111 }
 112
 113 struct cifs_tcon *
 114 tcon_info_alloc(bool dir_leases_enabled, enum smb3_tcon_ref_trace trace)
 115 {
 116         struct cifs_tcon *ret_buf;
 117         static atomic_t tcon_debug_id;
 118
 119         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 120         if (!ret_buf)
 121                 return NULL;
 122
 123         if (dir_leases_enabled == true) {
 124                 ret_buf->cfids = init_cached_dirs();
 125                 if (!ret_buf->cfids) {
 126                         kfree(ret_buf);
 127                         return NULL;
 128                 }
 129         }
 130         /* else ret_buf->cfids is already set to NULL above */
 131
 132         atomic_inc(&tconInfoAllocCount);
 133         ret_buf->status = TID_NEW;
 134         ret_buf->debug_id = atomic_inc_return(&tcon_debug_id);
 135         ret_buf->tc_count = 1;
 136         spin_lock_init(&ret_buf->tc_lock);
 137         INIT_LIST_HEAD(&ret_buf->openFileList);
 138         INIT_LIST_HEAD(&ret_buf->tcon_list);
 139         spin_lock_init(&ret_buf->open_file_lock);
 140         spin_lock_init(&ret_buf->stat_lock);
 141         atomic_set(&ret_buf->num_local_opens, 0);
 142         atomic_set(&ret_buf->num_remote_opens, 0);
 143         ret_buf->stats_from_time = ktime_get_real_seconds();
 144 #ifdef CONFIG_CIFS_FSCACHE
 145         mutex_init(&ret_buf->fscache_lock);
 146 #endif
 147         trace_smb3_tcon_ref(ret_buf->debug_id, ret_buf->tc_count, trace);
 148
 149         return ret_buf;
 150 }
 151
 152 void
 153 tconInfoFree(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 154 {
 155         if (tcon == NULL) {
 156                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 157                 return;
 158         }
 159         trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace);
 160         free_cached_dirs(tcon->cfids);
 161         atomic_dec(&tconInfoAllocCount);
 162         kfree(tcon->nativeFileSystem);
 163         kfree_sensitive(tcon->password);
 164         kfree(tcon->origin_fullpath);
 165         kfree(tcon);
 166 }
 167
 168 struct smb_hdr *
 169 cifs_buf_get(void)
 170 {
 171         struct smb_hdr *ret_buf = NULL;
 172         /*
 173          * SMB2 header is bigger than CIFS one - no problems to clean some
 174          * more bytes for CIFS.
 175          */
 176         size_t buf_size = sizeof(struct smb2_hdr);
 177
 178         /*
 179          * We could use negotiated size instead of max_msgsize -
 180          * but it may be more efficient to always alloc same size
 181          * albeit slightly larger than necessary and maxbuffersize
 182          * defaults to this and can not be bigger.
 183          */
 184         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 185
 186         /* clear the first few header bytes */
 187         /* for most paths, more is cleared in header_assemble */
 188         memset(ret_buf, 0, buf_size + 3);
 189         atomic_inc(&buf_alloc_count);
 190 #ifdef CONFIG_CIFS_STATS2
 191         atomic_inc(&total_buf_alloc_count);
 192 #endif /* CONFIG_CIFS_STATS2 */
 193
 194         return ret_buf;
 195 }
 196
 197 void
 198 cifs_buf_release(void *buf_to_free)
 199 {
 200         if (buf_to_free == NULL) {
 201                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 202                 return;
 203         }
 204         mempool_free(buf_to_free, cifs_req_poolp);
 205
 206         atomic_dec(&buf_alloc_count);
 207         return;
 208 }
 209
 210 struct smb_hdr *
 211 cifs_small_buf_get(void)
 212 {
 213         struct smb_hdr *ret_buf = NULL;
 214
 215 /* We could use negotiated size instead of max_msgsize -
 216    but it may be more efficient to always alloc same size
 217    albeit slightly larger than necessary and maxbuffersize
 218    defaults to this and can not be bigger */
 219         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 220         /* No need to clear memory here, cleared in header assemble */
 221         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 222         atomic_inc(&small_buf_alloc_count);
 223 #ifdef CONFIG_CIFS_STATS2
 224         atomic_inc(&total_small_buf_alloc_count);
 225 #endif /* CONFIG_CIFS_STATS2 */
 226
 227         return ret_buf;
 228 }
 229
 230 void
 231 cifs_small_buf_release(void *buf_to_free)
 232 {
 233
 234         if (buf_to_free == NULL) {
 235                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 236                 return;
 237         }
 238         mempool_free(buf_to_free, cifs_sm_req_poolp);
 239
 240         atomic_dec(&small_buf_alloc_count);
 241         return;
 242 }
 243
 244 void
 245 free_rsp_buf(int resp_buftype, void *rsp)
 246 {
 247         if (resp_buftype == CIFS_SMALL_BUFFER)
 248                 cifs_small_buf_release(rsp);
 249         else if (resp_buftype == CIFS_LARGE_BUFFER)
 250                 cifs_buf_release(rsp);
 251 }
 252
 253 /* NB: MID can not be set if treeCon not passed in, in that
 254    case it is responsbility of caller to set the mid */
 255 void
 256 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 257                 const struct cifs_tcon *treeCon, int word_count
 258                 /* length of fixed section (word count) in two byte units  */)
 259 {
 260         char *temp = (char *) buffer;
 261
 262         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 263
 264         buffer->smb_buf_length = cpu_to_be32(
 265             (2 * word_count) + sizeof(struct smb_hdr) -
 266             4 /*  RFC 1001 length field does not count */  +
 267             2 /* for bcc field itself */) ;
 268
 269         buffer->Protocol[0] = 0xFF;
 270         buffer->Protocol[1] = 'S';
 271         buffer->Protocol[2] = 'M';
 272         buffer->Protocol[3] = 'B';
 273         buffer->Command = smb_command;
 274         buffer->Flags = 0x00;   /* case sensitive */
 275         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 276         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 277         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 278         if (treeCon) {
 279                 buffer->Tid = treeCon->tid;
 280                 if (treeCon->ses) {
 281                         if (treeCon->ses->capabilities & CAP_UNICODE)
 282                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 283                         if (treeCon->ses->capabilities & CAP_STATUS32)
 284                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 285
 286                         /* Uid is not converted */
 287                         buffer->Uid = treeCon->ses->Suid;
 288                         if (treeCon->ses->server)
 289                                 buffer->Mid = get_next_mid(treeCon->ses->server);
 290                 }
 291                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 292                         buffer->Flags2 |= SMBFLG2_DFS;
 293                 if (treeCon->nocase)
 294                         buffer->Flags  |= SMBFLG_CASELESS;
 295                 if ((treeCon->ses) && (treeCon->ses->server))
 296                         if (treeCon->ses->server->sign)
 297                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 298         }
 299
 300 /*  endian conversion of flags is now done just before sending */
 301         buffer->WordCount = (char) word_count;
 302         return;
 303 }
 304
 305 static int
 306 check_smb_hdr(struct smb_hdr *smb)
 307 {
 308         /* does it have the right SMB "signature" ? */
 309         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 310                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 311                          *(unsigned int *)smb->Protocol);
 312                 return 1;
 313         }
 314
 315         /* if it's a response then accept */
 316         if (smb->Flags & SMBFLG_RESPONSE)
 317                 return 0;
 318
 319         /* only one valid case where server sends us request */
 320         if (smb->Command == SMB_COM_LOCKING_ANDX)
 321                 return 0;
 322
 323         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 324                  get_mid(smb));
 325         return 1;
 326 }
 327
 328 int
 329 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 330 {
 331         struct smb_hdr *smb = (struct smb_hdr *)buf;
 332         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 333         __u32 clc_len;  /* calculated length */
 334         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 335                  total_read, rfclen);
 336
 337         /* is this frame too small to even get to a BCC? */
 338         if (total_read < 2 + sizeof(struct smb_hdr)) {
 339                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 340                             && (smb->Status.CifsError != 0)) {
 341                         /* it's an error return */
 342                         smb->WordCount = 0;
 343                         /* some error cases do not return wct and bcc */
 344                         return 0;
 345                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 346                                 (smb->WordCount == 0)) {
 347                         char *tmp = (char *)smb;
 348                         /* Need to work around a bug in two servers here */
 349                         /* First, check if the part of bcc they sent was zero */
 350                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 351                                 /* some servers return only half of bcc
 352                                  * on simple responses (wct, bcc both zero)
 353                                  * in particular have seen this on
 354                                  * ulogoffX and FindClose. This leaves
 355                                  * one byte of bcc potentially unitialized
 356                                  */
 357                                 /* zero rest of bcc */
 358                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 359                                 return 0;
 360                         }
 361                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 362                 } else {
 363                         cifs_dbg(VFS, "Length less than smb header size\n");
 364                 }
 365                 return -EIO;
 366         } else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
 367                 cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
 368                          __func__, smb->WordCount);
 369                 return -EIO;
 370         }
 371
 372         /* otherwise, there is enough to get to the BCC */
 373         if (check_smb_hdr(smb))
 374                 return -EIO;
 375         clc_len = smbCalcSize(smb);
 376
 377         if (4 + rfclen != total_read) {
 378                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 379                          rfclen);
 380                 return -EIO;
 381         }
 382
 383         if (4 + rfclen != clc_len) {
 384                 __u16 mid = get_mid(smb);
 385                 /* check if bcc wrapped around for large read responses */
 386                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 387                         /* check if lengths match mod 64K */
 388                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 389                                 return 0; /* bcc wrapped */
 390                 }
 391                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 392                          clc_len, 4 + rfclen, mid);
 393
 394                 if (4 + rfclen < clc_len) {
 395                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 396                                  rfclen, mid);
 397                         return -EIO;
 398                 } else if (rfclen > clc_len + 512) {
 399                         /*
 400                          * Some servers (Windows XP in particular) send more
 401                          * data than the lengths in the SMB packet would
 402                          * indicate on certain calls (byte range locks and
 403                          * trans2 find first calls in particular). While the
 404                          * client can handle such a frame by ignoring the
 405                          * trailing data, we choose limit the amount of extra
 406                          * data to 512 bytes.
 407                          */
 408                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 409                                  rfclen, mid);
 410                         return -EIO;
 411                 }
 412         }
 413         return 0;
 414 }
 415
 416 bool
 417 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 418 {
 419         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 420         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 421         struct TCP_Server_Info *pserver;
 422         struct cifs_ses *ses;
 423         struct cifs_tcon *tcon;
 424         struct cifsInodeInfo *pCifsInode;
 425         struct cifsFileInfo *netfile;
 426
 427         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 428         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 429            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 430                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 431                         (struct smb_com_transaction_change_notify_rsp *)buf;
 432                 struct file_notify_information *pnotify;
 433                 __u32 data_offset = 0;
 434                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 435
 436                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 437                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 438
 439                         if (data_offset >
 440                             len - sizeof(struct file_notify_information)) {
 441                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
 442                                          data_offset);
 443                                 return true;
 444                         }
 445                         pnotify = (struct file_notify_information *)
 446                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 447                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 448                                  pnotify->FileName, pnotify->Action);
 449                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 450                                 sizeof(struct smb_hdr)+60); */
 451                         return true;
 452                 }
 453                 if (pSMBr->hdr.Status.CifsError) {
 454                         cifs_dbg(FYI, "notify err 0x%x\n",
 455                                  pSMBr->hdr.Status.CifsError);
 456                         return true;
 457                 }
 458                 return false;
 459         }
 460         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 461                 return false;
 462         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 463                 /* no sense logging error on invalid handle on oplock
 464                    break - harmless race between close request and oplock
 465                    break response is expected from time to time writing out
 466                    large dirty files cached on the client */
 467                 if ((NT_STATUS_INVALID_HANDLE) ==
 468                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 469                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
 470                         return true;
 471                 } else if (ERRbadfid ==
 472                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 473                         return true;
 474                 } else {
 475                         return false; /* on valid oplock brk we get "request" */
 476                 }
 477         }
 478         if (pSMB->hdr.WordCount != 8)
 479                 return false;
 480
 481         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 482                  pSMB->LockType, pSMB->OplockLevel);
 483         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 484                 return false;
 485
 486         /* If server is a channel, select the primary channel */
 487         pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
 488
 489         /* look up tcon based on tid & uid */
 490         spin_lock(&cifs_tcp_ses_lock);
 491         list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 492                 if (cifs_ses_exiting(ses))
 493                         continue;
 494                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 495                         if (tcon->tid != buf->Tid)
 496                                 continue;
 497
 498                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 499                         spin_lock(&tcon->open_file_lock);
 500                         list_for_each_entry(netfile, &tcon->openFileList, tlist) {
 501                                 if (pSMB->Fid != netfile->fid.netfid)
 502                                         continue;
 503
 504                                 cifs_dbg(FYI, "file id match, oplock break\n");
 505                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 506
 507                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 508                                         &pCifsInode->flags);
 509
 510                                 netfile->oplock_epoch = 0;
 511                                 netfile->oplock_level = pSMB->OplockLevel;
 512                                 netfile->oplock_break_cancelled = false;
 513                                 cifs_queue_oplock_break(netfile);
 514
 515                                 spin_unlock(&tcon->open_file_lock);
 516                                 spin_unlock(&cifs_tcp_ses_lock);
 517                                 return true;
 518                         }
 519                         spin_unlock(&tcon->open_file_lock);
 520                         spin_unlock(&cifs_tcp_ses_lock);
 521                         cifs_dbg(FYI, "No matching file for oplock break\n");
 522                         return true;
 523                 }
 524         }
 525         spin_unlock(&cifs_tcp_ses_lock);
 526         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 527         return true;
 528 }
 529
 530 void
 531 dump_smb(void *buf, int smb_buf_length)
 532 {
 533         if (traceSMB == 0)
 534                 return;
 535
 536         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 537                        smb_buf_length, true);
 538 }
 539
 540 void
 541 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 542 {
 543         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 544                 struct cifs_tcon *tcon = NULL;
 545
 546                 if (cifs_sb->master_tlink)
 547                         tcon = cifs_sb_master_tcon(cifs_sb);
 548
 549                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 550                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 551                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 552                          tcon ? tcon->tree_name : "new server");
 553                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 554                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 555
 556         }
 557 }
 558
 559 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 560 {
 561         oplock &= 0xF;
 562
 563         if (oplock == OPLOCK_EXCLUSIVE) {
 564                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 565                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 566                          &cinode->netfs.inode);
 567         } else if (oplock == OPLOCK_READ) {
 568                 cinode->oplock = CIFS_CACHE_READ_FLG;
 569                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 570                          &cinode->netfs.inode);
 571         } else
 572                 cinode->oplock = 0;
 573 }
 574
 575 /*
 576  * We wait for oplock breaks to be processed before we attempt to perform
 577  * writes.
 578  */
 579 int cifs_get_writer(struct cifsInodeInfo *cinode)
 580 {
 581         int rc;
 582
 583 start:
 584         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 585                          TASK_KILLABLE);
 586         if (rc)
 587                 return rc;
 588
 589         spin_lock(&cinode->writers_lock);
 590         if (!cinode->writers)
 591                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 592         cinode->writers++;
 593         /* Check to see if we have started servicing an oplock break */
 594         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 595                 cinode->writers--;
 596                 if (cinode->writers == 0) {
 597                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 598                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 599                 }
 600                 spin_unlock(&cinode->writers_lock);
 601                 goto start;
 602         }
 603         spin_unlock(&cinode->writers_lock);
 604         return 0;
 605 }
 606
 607 void cifs_put_writer(struct cifsInodeInfo *cinode)
 608 {
 609         spin_lock(&cinode->writers_lock);
 610         cinode->writers--;
 611         if (cinode->writers == 0) {
 612                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 613                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 614         }
 615         spin_unlock(&cinode->writers_lock);
 616 }
 617
 618 /**
 619  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 620  * @cfile: The file to break the oplock on
 621  *
 622  * This function is called from the demultiplex thread when it
 623  * receives an oplock break for @cfile.
 624  *
 625  * Assumes the tcon->open_file_lock is held.
 626  * Assumes cfile->file_info_lock is NOT held.
 627  */
 628 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 629 {
 630         /*
 631          * Bump the handle refcount now while we hold the
 632          * open_file_lock to enforce the validity of it for the oplock
 633          * break handler. The matching put is done at the end of the
 634          * handler.
 635          */
 636         cifsFileInfo_get(cfile);
 637
 638         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 639 }
 640
 641 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 642 {
 643         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 644         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 645 }
 646
 647 bool
 648 backup_cred(struct cifs_sb_info *cifs_sb)
 649 {
 650         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 651                 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
 652                         return true;
 653         }
 654         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 655                 if (in_group_p(cifs_sb->ctx->backupgid))
 656                         return true;
 657         }
 658
 659         return false;
 660 }
 661
 662 void
 663 cifs_del_pending_open(struct cifs_pending_open *open)
 664 {
 665         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 666         list_del(&open->olist);
 667         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 668 }
 669
 670 void
 671 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 672                              struct cifs_pending_open *open)
 673 {
 674         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 675         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 676         open->tlink = tlink;
 677         fid->pending_open = open;
 678         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 679 }
 680
 681 void
 682 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 683                       struct cifs_pending_open *open)
 684 {
 685         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 686         cifs_add_pending_open_locked(fid, tlink, open);
 687         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 688 }
 689
 690 /*
 691  * Critical section which runs after acquiring deferred_lock.
 692  * As there is no reference count on cifs_deferred_close, pdclose
 693  * should not be used outside deferred_lock.
 694  */
 695 bool
 696 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
 697 {
 698         struct cifs_deferred_close *dclose;
 699
 700         list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
 701                 if ((dclose->netfid == cfile->fid.netfid) &&
 702                         (dclose->persistent_fid == cfile->fid.persistent_fid) &&
 703                         (dclose->volatile_fid == cfile->fid.volatile_fid)) {
 704                         *pdclose = dclose;
 705                         return true;
 706                 }
 707         }
 708         return false;
 709 }
 710
 711 /*
 712  * Critical section which runs after acquiring deferred_lock.
 713  */
 714 void
 715 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
 716 {
 717         bool is_deferred = false;
 718         struct cifs_deferred_close *pdclose;
 719
 720         is_deferred = cifs_is_deferred_close(cfile, &pdclose);
 721         if (is_deferred) {
 722                 kfree(dclose);
 723                 return;
 724         }
 725
 726         dclose->tlink = cfile->tlink;
 727         dclose->netfid = cfile->fid.netfid;
 728         dclose->persistent_fid = cfile->fid.persistent_fid;
 729         dclose->volatile_fid = cfile->fid.volatile_fid;
 730         list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
 731 }
 732
 733 /*
 734  * Critical section which runs after acquiring deferred_lock.
 735  */
 736 void
 737 cifs_del_deferred_close(struct cifsFileInfo *cfile)
 738 {
 739         bool is_deferred = false;
 740         struct cifs_deferred_close *dclose;
 741
 742         is_deferred = cifs_is_deferred_close(cfile, &dclose);
 743         if (!is_deferred)
 744                 return;
 745         list_del(&dclose->dlist);
 746         kfree(dclose);
 747 }
 748
 749 void
 750 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
 751 {
 752         struct cifsFileInfo *cfile = NULL;
 753         struct file_list *tmp_list, *tmp_next_list;
 754         struct list_head file_head;
 755
 756         if (cifs_inode == NULL)
 757                 return;
 758
 759         INIT_LIST_HEAD(&file_head);
 760         spin_lock(&cifs_inode->open_file_lock);
 761         list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
 762                 if (delayed_work_pending(&cfile->deferred)) {
 763                         if (cancel_delayed_work(&cfile->deferred)) {
 764                                 spin_lock(&cifs_inode->deferred_lock);
 765                                 cifs_del_deferred_close(cfile);
 766                                 spin_unlock(&cifs_inode->deferred_lock);
 767
 768                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 769                                 if (tmp_list == NULL)
 770                                         break;
 771                                 tmp_list->cfile = cfile;
 772                                 list_add_tail(&tmp_list->list, &file_head);
 773                         }
 774                 }
 775         }
 776         spin_unlock(&cifs_inode->open_file_lock);
 777
 778         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 779                 _cifsFileInfo_put(tmp_list->cfile, false, false);
 780                 list_del(&tmp_list->list);
 781                 kfree(tmp_list);
 782         }
 783 }
 784
 785 void
 786 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 787 {
 788         struct cifsFileInfo *cfile;
 789         struct file_list *tmp_list, *tmp_next_list;
 790         struct list_head file_head;
 791
 792         INIT_LIST_HEAD(&file_head);
 793         spin_lock(&tcon->open_file_lock);
 794         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 795                 if (delayed_work_pending(&cfile->deferred)) {
 796                         if (cancel_delayed_work(&cfile->deferred)) {
 797                                 spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 798                                 cifs_del_deferred_close(cfile);
 799                                 spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 800
 801                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 802                                 if (tmp_list == NULL)
 803                                         break;
 804                                 tmp_list->cfile = cfile;
 805                                 list_add_tail(&tmp_list->list, &file_head);
 806                         }
 807                 }
 808         }
 809         spin_unlock(&tcon->open_file_lock);
 810
 811         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 812                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 813                 list_del(&tmp_list->list);
 814                 kfree(tmp_list);
 815         }
 816 }
 817 void
 818 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
 819 {
 820         struct cifsFileInfo *cfile;
 821         struct file_list *tmp_list, *tmp_next_list;
 822         struct list_head file_head;
 823         void *page;
 824         const char *full_path;
 825
 826         INIT_LIST_HEAD(&file_head);
 827         page = alloc_dentry_path();
 828         spin_lock(&tcon->open_file_lock);
 829         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 830                 full_path = build_path_from_dentry(cfile->dentry, page);
 831                 if (strstr(full_path, path)) {
 832                         if (delayed_work_pending(&cfile->deferred)) {
 833                                 if (cancel_delayed_work(&cfile->deferred)) {
 834                                         spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 835                                         cifs_del_deferred_close(cfile);
 836                                         spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 837
 838                                         tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 839                                         if (tmp_list == NULL)
 840                                                 break;
 841                                         tmp_list->cfile = cfile;
 842                                         list_add_tail(&tmp_list->list, &file_head);
 843                                 }
 844                         }
 845                 }
 846         }
 847         spin_unlock(&tcon->open_file_lock);
 848
 849         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 850                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 851                 list_del(&tmp_list->list);
 852                 kfree(tmp_list);
 853         }
 854         free_dentry_path(page);
 855 }
 856
 857 /*
 858  * If a dentry has been deleted, all corresponding open handles should know that
 859  * so that we do not defer close them.
 860  */
 861 void cifs_mark_open_handles_for_deleted_file(struct inode *inode,
 862                                              const char *path)
 863 {
 864         struct cifsFileInfo *cfile;
 865         void *page;
 866         const char *full_path;
 867         struct cifsInodeInfo *cinode = CIFS_I(inode);
 868
 869         page = alloc_dentry_path();
 870         spin_lock(&cinode->open_file_lock);
 871
 872         /*
 873          * note: we need to construct path from dentry and compare only if the
 874          * inode has any hardlinks. When number of hardlinks is 1, we can just
 875          * mark all open handles since they are going to be from the same file.
 876          */
 877         if (inode->i_nlink > 1) {
 878                 list_for_each_entry(cfile, &cinode->openFileList, flist) {
 879                         full_path = build_path_from_dentry(cfile->dentry, page);
 880                         if (!IS_ERR(full_path) && strcmp(full_path, path) == 0)
 881                                 cfile->status_file_deleted = true;
 882                 }
 883         } else {
 884                 list_for_each_entry(cfile, &cinode->openFileList, flist)
 885                         cfile->status_file_deleted = true;
 886         }
 887         spin_unlock(&cinode->open_file_lock);
 888         free_dentry_path(page);
 889 }
 890
 891 /* parses DFS referral V3 structure
 892  * caller is responsible for freeing target_nodes
 893  * returns:
 894  * - on success - 0
 895  * - on failure - errno
 896  */
 897 int
 898 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 899                     unsigned int *num_of_nodes,
 900                     struct dfs_info3_param **target_nodes,
 901                     const struct nls_table *nls_codepage, int remap,
 902                     const char *searchName, bool is_unicode)
 903 {
 904         int i, rc = 0;
 905         char *data_end;
 906         struct dfs_referral_level_3 *ref;
 907
 908         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 909
 910         if (*num_of_nodes < 1) {
 911                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 912                          *num_of_nodes);
 913                 rc = -EINVAL;
 914                 goto parse_DFS_referrals_exit;
 915         }
 916
 917         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 918         if (ref->VersionNumber != cpu_to_le16(3)) {
 919                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 920                          le16_to_cpu(ref->VersionNumber));
 921                 rc = -EINVAL;
 922                 goto parse_DFS_referrals_exit;
 923         }
 924
 925         /* get the upper boundary of the resp buffer */
 926         data_end = (char *)rsp + rsp_size;
 927
 928         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 929                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 930
 931         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 932                                 GFP_KERNEL);
 933         if (*target_nodes == NULL) {
 934                 rc = -ENOMEM;
 935                 goto parse_DFS_referrals_exit;
 936         }
 937
 938         /* collect necessary data from referrals */
 939         for (i = 0; i < *num_of_nodes; i++) {
 940                 char *temp;
 941                 int max_len;
 942                 struct dfs_info3_param *node = (*target_nodes)+i;
 943
 944                 node->flags = le32_to_cpu(rsp->DFSFlags);
 945                 if (is_unicode) {
 946                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 947                                                 GFP_KERNEL);
 948                         if (tmp == NULL) {
 949                                 rc = -ENOMEM;
 950                                 goto parse_DFS_referrals_exit;
 951                         }
 952                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 953                                            PATH_MAX, nls_codepage, remap);
 954                         node->path_consumed = cifs_utf16_bytes(tmp,
 955                                         le16_to_cpu(rsp->PathConsumed),
 956                                         nls_codepage);
 957                         kfree(tmp);
 958                 } else
 959                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 960
 961                 node->server_type = le16_to_cpu(ref->ServerType);
 962                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 963
 964                 /* copy DfsPath */
 965                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 966                 max_len = data_end - temp;
 967                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 968                                                 is_unicode, nls_codepage);
 969                 if (!node->path_name) {
 970                         rc = -ENOMEM;
 971                         goto parse_DFS_referrals_exit;
 972                 }
 973
 974                 /* copy link target UNC */
 975                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 976                 max_len = data_end - temp;
 977                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 978                                                 is_unicode, nls_codepage);
 979                 if (!node->node_name) {
 980                         rc = -ENOMEM;
 981                         goto parse_DFS_referrals_exit;
 982                 }
 983
 984                 node->ttl = le32_to_cpu(ref->TimeToLive);
 985
 986                 ref++;
 987         }
 988
 989 parse_DFS_referrals_exit:
 990         if (rc) {
 991                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 992                 *target_nodes = NULL;
 993                 *num_of_nodes = 0;
 994         }
 995         return rc;
 996 }
 997
 998 struct cifs_aio_ctx *
 999 cifs_aio_ctx_alloc(void)
1000 {
1001         struct cifs_aio_ctx *ctx;
1002
1003         /*
1004          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
1005          * to false so that we know when we have to unreference pages within
1006          * cifs_aio_ctx_release()
1007          */
1008         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
1009         if (!ctx)
1010                 return NULL;
1011
1012         INIT_LIST_HEAD(&ctx->list);
1013         mutex_init(&ctx->aio_mutex);
1014         init_completion(&ctx->done);
1015         kref_init(&ctx->refcount);
1016         return ctx;
1017 }
1018
1019 void
1020 cifs_aio_ctx_release(struct kref *refcount)
1021 {
1022         struct cifs_aio_ctx *ctx = container_of(refcount,
1023                                         struct cifs_aio_ctx, refcount);
1024
1025         cifsFileInfo_put(ctx->cfile);
1026
1027         /*
1028          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
1029          * which means that iov_iter_extract_pages() was a success and thus
1030          * that we may have references or pins on pages that we need to
1031          * release.
1032          */
1033         if (ctx->bv) {
1034                 if (ctx->should_dirty || ctx->bv_need_unpin) {
1035                         unsigned int i;
1036
1037                         for (i = 0; i < ctx->nr_pinned_pages; i++) {
1038                                 struct page *page = ctx->bv[i].bv_page;
1039
1040                                 if (ctx->should_dirty)
1041                                         set_page_dirty(page);
1042                                 if (ctx->bv_need_unpin)
1043                                         unpin_user_page(page);
1044                         }
1045                 }
1046                 kvfree(ctx->bv);
1047         }
1048
1049         kfree(ctx);
1050 }
1051
1052 /**
1053  * cifs_alloc_hash - allocate hash and hash context together
1054  * @name: The name of the crypto hash algo
1055  * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1056  *
1057  * The caller has to make sure @sdesc is initialized to either NULL or
1058  * a valid context. It can be freed via cifs_free_hash().
1059  */
1060 int
1061 cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1062 {
1063         int rc = 0;
1064         struct crypto_shash *alg = NULL;
1065
1066         if (*sdesc)
1067                 return 0;
1068
1069         alg = crypto_alloc_shash(name, 0, 0);
1070         if (IS_ERR(alg)) {
1071                 cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1072                 rc = PTR_ERR(alg);
1073                 *sdesc = NULL;
1074                 return rc;
1075         }
1076
1077         *sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1078         if (*sdesc == NULL) {
1079                 cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1080                 crypto_free_shash(alg);
1081                 return -ENOMEM;
1082         }
1083
1084         (*sdesc)->tfm = alg;
1085         return 0;
1086 }
1087
1088 /**
1089  * cifs_free_hash - free hash and hash context together
1090  * @sdesc: Where to find the pointer to the hash TFM
1091  *
1092  * Freeing a NULL descriptor is safe.
1093  */
1094 void
1095 cifs_free_hash(struct shash_desc **sdesc)
1096 {
1097         if (unlikely(!sdesc) || !*sdesc)
1098                 return;
1099
1100         if ((*sdesc)->tfm) {
1101                 crypto_free_shash((*sdesc)->tfm);
1102                 (*sdesc)->tfm = NULL;
1103         }
1104
1105         kfree_sensitive(*sdesc);
1106         *sdesc = NULL;
1107 }
1108
1109 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1110 {
1111         const char *end;
1112
1113         /* skip initial slashes */
1114         while (*unc && (*unc == '\\' || *unc == '/'))
1115                 unc++;
1116
1117         end = unc;
1118
1119         while (*end && !(*end == '\\' || *end == '/'))
1120                 end++;
1121
1122         *h = unc;
1123         *len = end - unc;
1124 }
1125
1126 /**
1127  * copy_path_name - copy src path to dst, possibly truncating
1128  * @dst: The destination buffer
1129  * @src: The source name
1130  *
1131  * returns number of bytes written (including trailing nul)
1132  */
1133 int copy_path_name(char *dst, const char *src)
1134 {
1135         int name_len;
1136
1137         /*
1138          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1139          * will truncate and strlen(dst) will be PATH_MAX-1
1140          */
1141         name_len = strscpy(dst, src, PATH_MAX);
1142         if (WARN_ON_ONCE(name_len < 0))
1143                 name_len = PATH_MAX-1;
1144
1145         /* we count the trailing nul */
1146         name_len++;
1147         return name_len;
1148 }
1149
1150 struct super_cb_data {
1151         void *data;
1152         struct super_block *sb;
1153 };
1154
1155 static void tcon_super_cb(struct super_block *sb, void *arg)
1156 {
1157         struct super_cb_data *sd = arg;
1158         struct cifs_sb_info *cifs_sb;
1159         struct cifs_tcon *t1 = sd->data, *t2;
1160
1161         if (sd->sb)
1162                 return;
1163
1164         cifs_sb = CIFS_SB(sb);
1165         t2 = cifs_sb_master_tcon(cifs_sb);
1166
1167         spin_lock(&t2->tc_lock);
1168         if (t1->ses == t2->ses &&
1169             t1->ses->server == t2->ses->server &&
1170             t2->origin_fullpath &&
1171             dfs_src_pathname_equal(t2->origin_fullpath, t1->origin_fullpath))
1172                 sd->sb = sb;
1173         spin_unlock(&t2->tc_lock);
1174 }
1175
1176 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1177                                             void *data)
1178 {
1179         struct super_cb_data sd = {
1180                 .data = data,
1181                 .sb = NULL,
1182         };
1183         struct file_system_type **fs_type = (struct file_system_type *[]) {
1184                 &cifs_fs_type, &smb3_fs_type, NULL,
1185         };
1186
1187         for (; *fs_type; fs_type++) {
1188                 iterate_supers_type(*fs_type, f, &sd);
1189                 if (sd.sb) {
1190                         /*
1191                          * Grab an active reference in order to prevent automounts (DFS links)
1192                          * of expiring and then freeing up our cifs superblock pointer while
1193                          * we're doing failover.
1194                          */
1195                         cifs_sb_active(sd.sb);
1196                         return sd.sb;
1197                 }
1198         }
1199         pr_warn_once("%s: could not find dfs superblock\n", __func__);
1200         return ERR_PTR(-EINVAL);
1201 }
1202
1203 static void __cifs_put_super(struct super_block *sb)
1204 {
1205         if (!IS_ERR_OR_NULL(sb))
1206                 cifs_sb_deactive(sb);
1207 }
1208
1209 struct super_block *cifs_get_dfs_tcon_super(struct cifs_tcon *tcon)
1210 {
1211         spin_lock(&tcon->tc_lock);
1212         if (!tcon->origin_fullpath) {
1213                 spin_unlock(&tcon->tc_lock);
1214                 return ERR_PTR(-ENOENT);
1215         }
1216         spin_unlock(&tcon->tc_lock);
1217         return __cifs_get_super(tcon_super_cb, tcon);
1218 }
1219
1220 void cifs_put_tcp_super(struct super_block *sb)
1221 {
1222         __cifs_put_super(sb);
1223 }
1224
1225 #ifdef CONFIG_CIFS_DFS_UPCALL
1226 int match_target_ip(struct TCP_Server_Info *server,
1227                     const char *share, size_t share_len,
1228                     bool *result)
1229 {
1230         int rc;
1231         char *target;
1232         struct sockaddr_storage ss;
1233
1234         *result = false;
1235
1236         target = kzalloc(share_len + 3, GFP_KERNEL);
1237         if (!target)
1238                 return -ENOMEM;
1239
1240         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1241
1242         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1243
1244         rc = dns_resolve_server_name_to_ip(target, (struct sockaddr *)&ss, NULL);
1245         kfree(target);
1246
1247         if (rc < 0)
1248                 return rc;
1249
1250         spin_lock(&server->srv_lock);
1251         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
1252         spin_unlock(&server->srv_lock);
1253         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1254         return 0;
1255 }
1256
1257 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1258 {
1259         int rc;
1260
1261         kfree(cifs_sb->prepath);
1262         cifs_sb->prepath = NULL;
1263
1264         if (prefix && *prefix) {
1265                 cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1266                 if (IS_ERR(cifs_sb->prepath)) {
1267                         rc = PTR_ERR(cifs_sb->prepath);
1268                         cifs_sb->prepath = NULL;
1269                         return rc;
1270                 }
1271                 if (cifs_sb->prepath)
1272                         convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1273         }
1274
1275         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1276         return 0;
1277 }
1278
1279 /*
1280  * Handle weird Windows SMB server behaviour. It responds with
1281  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1282  * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1283  * non-ASCII unicode symbols.
1284  */
1285 int cifs_inval_name_dfs_link_error(const unsigned int xid,
1286                                    struct cifs_tcon *tcon,
1287                                    struct cifs_sb_info *cifs_sb,
1288                                    const char *full_path,
1289                                    bool *islink)
1290 {
1291         struct cifs_ses *ses = tcon->ses;
1292         size_t len;
1293         char *path;
1294         char *ref_path;
1295
1296         *islink = false;
1297
1298         /*
1299          * Fast path - skip check when @full_path doesn't have a prefix path to
1300          * look up or tcon is not DFS.
1301          */
1302         if (strlen(full_path) < 2 || !cifs_sb ||
1303             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1304             !is_tcon_dfs(tcon))
1305                 return 0;
1306
1307         spin_lock(&tcon->tc_lock);
1308         if (!tcon->origin_fullpath) {
1309                 spin_unlock(&tcon->tc_lock);
1310                 return 0;
1311         }
1312         spin_unlock(&tcon->tc_lock);
1313
1314         /*
1315          * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1316          * to get a referral to figure out whether it is an DFS link.
1317          */
1318         len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1319         path = kmalloc(len, GFP_KERNEL);
1320         if (!path)
1321                 return -ENOMEM;
1322
1323         scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1324         ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1325                                             cifs_remap(cifs_sb));
1326         kfree(path);
1327
1328         if (IS_ERR(ref_path)) {
1329                 if (PTR_ERR(ref_path) != -EINVAL)
1330                         return PTR_ERR(ref_path);
1331         } else {
1332                 struct dfs_info3_param *refs = NULL;
1333                 int num_refs = 0;
1334
1335                 /*
1336                  * XXX: we are not using dfs_cache_find() here because we might
1337                  * end up filling all the DFS cache and thus potentially
1338                  * removing cached DFS targets that the client would eventually
1339                  * need during failover.
1340                  */
1341                 ses = CIFS_DFS_ROOT_SES(ses);
1342                 if (ses->server->ops->get_dfs_refer &&
1343                     !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1344                                                      &num_refs, cifs_sb->local_nls,
1345                                                      cifs_remap(cifs_sb)))
1346                         *islink = refs[0].server_type == DFS_TYPE_LINK;
1347                 free_dfs_info_array(refs, num_refs);
1348                 kfree(ref_path);
1349         }
1350         return 0;
1351 }
1352 #endif
1353
1354 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1355 {
1356         int timeout = 10;
1357         int rc;
1358
1359         spin_lock(&server->srv_lock);
1360         if (server->tcpStatus != CifsNeedReconnect) {
1361                 spin_unlock(&server->srv_lock);
1362                 return 0;
1363         }
1364         timeout *= server->nr_targets;
1365         spin_unlock(&server->srv_lock);
1366
1367         /*
1368          * Give demultiplex thread up to 10 seconds to each target available for
1369          * reconnect -- should be greater than cifs socket timeout which is 7
1370          * seconds.
1371          *
1372          * On "soft" mounts we wait once. Hard mounts keep retrying until
1373          * process is killed or server comes back on-line.
1374          */
1375         do {
1376                 rc = wait_event_interruptible_timeout(server->response_q,
1377                                                       (server->tcpStatus != CifsNeedReconnect),
1378                                                       timeout * HZ);
1379                 if (rc < 0) {
1380                         cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1381                                  __func__);
1382                         return -ERESTARTSYS;
1383                 }
1384
1385                 /* are we still trying to reconnect? */
1386                 spin_lock(&server->srv_lock);
1387                 if (server->tcpStatus != CifsNeedReconnect) {
1388                         spin_unlock(&server->srv_lock);
1389                         return 0;
1390                 }
1391                 spin_unlock(&server->srv_lock);
1392         } while (retry);
1393
1394         cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1395         return -EHOSTDOWN;
1396 }