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 #endif
  26 #include "fs_context.h"
  27 #include "cached_dir.h"
  28
  29 extern mempool_t *cifs_sm_req_poolp;
  30 extern mempool_t *cifs_req_poolp;
  31
  32 /* The xid serves as a useful identifier for each incoming vfs request,
  33    in a similar way to the mid which is useful to track each sent smb,
  34    and CurrentXid can also provide a running counter (although it
  35    will eventually wrap past zero) of the total vfs operations handled
  36    since the cifs fs was mounted */
  37
  38 unsigned int
  39 _get_xid(void)
  40 {
  41         unsigned int xid;
  42
  43         spin_lock(&GlobalMid_Lock);
  44         GlobalTotalActiveXid++;
  45
  46         /* keep high water mark for number of simultaneous ops in filesystem */
  47         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  48                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  49         if (GlobalTotalActiveXid > 65000)
  50                 cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  51         xid = GlobalCurrentXid++;
  52         spin_unlock(&GlobalMid_Lock);
  53         return xid;
  54 }
  55
  56 void
  57 _free_xid(unsigned int xid)
  58 {
  59         spin_lock(&GlobalMid_Lock);
  60         /* if (GlobalTotalActiveXid == 0)
  61                 BUG(); */
  62         GlobalTotalActiveXid--;
  63         spin_unlock(&GlobalMid_Lock);
  64 }
  65
  66 struct cifs_ses *
  67 sesInfoAlloc(void)
  68 {
  69         struct cifs_ses *ret_buf;
  70
  71         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  72         if (ret_buf) {
  73                 atomic_inc(&sesInfoAllocCount);
  74                 spin_lock_init(&ret_buf->ses_lock);
  75                 ret_buf->ses_status = SES_NEW;
  76                 ++ret_buf->ses_count;
  77                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  78                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  79                 mutex_init(&ret_buf->session_mutex);
  80                 spin_lock_init(&ret_buf->iface_lock);
  81                 INIT_LIST_HEAD(&ret_buf->iface_list);
  82                 spin_lock_init(&ret_buf->chan_lock);
  83         }
  84         return ret_buf;
  85 }
  86
  87 void
  88 sesInfoFree(struct cifs_ses *buf_to_free)
  89 {
  90         struct cifs_server_iface *iface = NULL, *niface = NULL;
  91
  92         if (buf_to_free == NULL) {
  93                 cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  94                 return;
  95         }
  96
  97         atomic_dec(&sesInfoAllocCount);
  98         kfree(buf_to_free->serverOS);
  99         kfree(buf_to_free->serverDomain);
 100         kfree(buf_to_free->serverNOS);
 101         kfree_sensitive(buf_to_free->password);
 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 tconInfoAlloc(void)
 115 {
 116         struct cifs_tcon *ret_buf;
 117
 118         ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 119         if (!ret_buf)
 120                 return NULL;
 121         ret_buf->cfids = init_cached_dirs();
 122         if (!ret_buf->cfids) {
 123                 kfree(ret_buf);
 124                 return NULL;
 125         }
 126
 127         atomic_inc(&tconInfoAllocCount);
 128         ret_buf->status = TID_NEW;
 129         ++ret_buf->tc_count;
 130         spin_lock_init(&ret_buf->tc_lock);
 131         INIT_LIST_HEAD(&ret_buf->openFileList);
 132         INIT_LIST_HEAD(&ret_buf->tcon_list);
 133         spin_lock_init(&ret_buf->open_file_lock);
 134         spin_lock_init(&ret_buf->stat_lock);
 135         atomic_set(&ret_buf->num_local_opens, 0);
 136         atomic_set(&ret_buf->num_remote_opens, 0);
 137
 138         return ret_buf;
 139 }
 140
 141 void
 142 tconInfoFree(struct cifs_tcon *tcon)
 143 {
 144         if (tcon == NULL) {
 145                 cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 146                 return;
 147         }
 148         free_cached_dirs(tcon->cfids);
 149         atomic_dec(&tconInfoAllocCount);
 150         kfree(tcon->nativeFileSystem);
 151         kfree_sensitive(tcon->password);
 152         kfree(tcon);
 153 }
 154
 155 struct smb_hdr *
 156 cifs_buf_get(void)
 157 {
 158         struct smb_hdr *ret_buf = NULL;
 159         /*
 160          * SMB2 header is bigger than CIFS one - no problems to clean some
 161          * more bytes for CIFS.
 162          */
 163         size_t buf_size = sizeof(struct smb2_hdr);
 164
 165         /*
 166          * We could use negotiated size instead of max_msgsize -
 167          * but it may be more efficient to always alloc same size
 168          * albeit slightly larger than necessary and maxbuffersize
 169          * defaults to this and can not be bigger.
 170          */
 171         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 172
 173         /* clear the first few header bytes */
 174         /* for most paths, more is cleared in header_assemble */
 175         memset(ret_buf, 0, buf_size + 3);
 176         atomic_inc(&buf_alloc_count);
 177 #ifdef CONFIG_CIFS_STATS2
 178         atomic_inc(&total_buf_alloc_count);
 179 #endif /* CONFIG_CIFS_STATS2 */
 180
 181         return ret_buf;
 182 }
 183
 184 void
 185 cifs_buf_release(void *buf_to_free)
 186 {
 187         if (buf_to_free == NULL) {
 188                 /* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 189                 return;
 190         }
 191         mempool_free(buf_to_free, cifs_req_poolp);
 192
 193         atomic_dec(&buf_alloc_count);
 194         return;
 195 }
 196
 197 struct smb_hdr *
 198 cifs_small_buf_get(void)
 199 {
 200         struct smb_hdr *ret_buf = NULL;
 201
 202 /* We could use negotiated size instead of max_msgsize -
 203    but it may be more efficient to always alloc same size
 204    albeit slightly larger than necessary and maxbuffersize
 205    defaults to this and can not be bigger */
 206         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 207         /* No need to clear memory here, cleared in header assemble */
 208         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 209         atomic_inc(&small_buf_alloc_count);
 210 #ifdef CONFIG_CIFS_STATS2
 211         atomic_inc(&total_small_buf_alloc_count);
 212 #endif /* CONFIG_CIFS_STATS2 */
 213
 214         return ret_buf;
 215 }
 216
 217 void
 218 cifs_small_buf_release(void *buf_to_free)
 219 {
 220
 221         if (buf_to_free == NULL) {
 222                 cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 223                 return;
 224         }
 225         mempool_free(buf_to_free, cifs_sm_req_poolp);
 226
 227         atomic_dec(&small_buf_alloc_count);
 228         return;
 229 }
 230
 231 void
 232 free_rsp_buf(int resp_buftype, void *rsp)
 233 {
 234         if (resp_buftype == CIFS_SMALL_BUFFER)
 235                 cifs_small_buf_release(rsp);
 236         else if (resp_buftype == CIFS_LARGE_BUFFER)
 237                 cifs_buf_release(rsp);
 238 }
 239
 240 /* NB: MID can not be set if treeCon not passed in, in that
 241    case it is responsbility of caller to set the mid */
 242 void
 243 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 244                 const struct cifs_tcon *treeCon, int word_count
 245                 /* length of fixed section (word count) in two byte units  */)
 246 {
 247         char *temp = (char *) buffer;
 248
 249         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 250
 251         buffer->smb_buf_length = cpu_to_be32(
 252             (2 * word_count) + sizeof(struct smb_hdr) -
 253             4 /*  RFC 1001 length field does not count */  +
 254             2 /* for bcc field itself */) ;
 255
 256         buffer->Protocol[0] = 0xFF;
 257         buffer->Protocol[1] = 'S';
 258         buffer->Protocol[2] = 'M';
 259         buffer->Protocol[3] = 'B';
 260         buffer->Command = smb_command;
 261         buffer->Flags = 0x00;   /* case sensitive */
 262         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 263         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 264         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 265         if (treeCon) {
 266                 buffer->Tid = treeCon->tid;
 267                 if (treeCon->ses) {
 268                         if (treeCon->ses->capabilities & CAP_UNICODE)
 269                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 270                         if (treeCon->ses->capabilities & CAP_STATUS32)
 271                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 272
 273                         /* Uid is not converted */
 274                         buffer->Uid = treeCon->ses->Suid;
 275                         if (treeCon->ses->server)
 276                                 buffer->Mid = get_next_mid(treeCon->ses->server);
 277                 }
 278                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 279                         buffer->Flags2 |= SMBFLG2_DFS;
 280                 if (treeCon->nocase)
 281                         buffer->Flags  |= SMBFLG_CASELESS;
 282                 if ((treeCon->ses) && (treeCon->ses->server))
 283                         if (treeCon->ses->server->sign)
 284                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 285         }
 286
 287 /*  endian conversion of flags is now done just before sending */
 288         buffer->WordCount = (char) word_count;
 289         return;
 290 }
 291
 292 static int
 293 check_smb_hdr(struct smb_hdr *smb)
 294 {
 295         /* does it have the right SMB "signature" ? */
 296         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 297                 cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 298                          *(unsigned int *)smb->Protocol);
 299                 return 1;
 300         }
 301
 302         /* if it's a response then accept */
 303         if (smb->Flags & SMBFLG_RESPONSE)
 304                 return 0;
 305
 306         /* only one valid case where server sends us request */
 307         if (smb->Command == SMB_COM_LOCKING_ANDX)
 308                 return 0;
 309
 310         cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 311                  get_mid(smb));
 312         return 1;
 313 }
 314
 315 int
 316 checkSMB(char *buf, unsigned int total_read, struct TCP_Server_Info *server)
 317 {
 318         struct smb_hdr *smb = (struct smb_hdr *)buf;
 319         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 320         __u32 clc_len;  /* calculated length */
 321         cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 322                  total_read, rfclen);
 323
 324         /* is this frame too small to even get to a BCC? */
 325         if (total_read < 2 + sizeof(struct smb_hdr)) {
 326                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 327                             && (smb->Status.CifsError != 0)) {
 328                         /* it's an error return */
 329                         smb->WordCount = 0;
 330                         /* some error cases do not return wct and bcc */
 331                         return 0;
 332                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 333                                 (smb->WordCount == 0)) {
 334                         char *tmp = (char *)smb;
 335                         /* Need to work around a bug in two servers here */
 336                         /* First, check if the part of bcc they sent was zero */
 337                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 338                                 /* some servers return only half of bcc
 339                                  * on simple responses (wct, bcc both zero)
 340                                  * in particular have seen this on
 341                                  * ulogoffX and FindClose. This leaves
 342                                  * one byte of bcc potentially unitialized
 343                                  */
 344                                 /* zero rest of bcc */
 345                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 346                                 return 0;
 347                         }
 348                         cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 349                 } else {
 350                         cifs_dbg(VFS, "Length less than smb header size\n");
 351                 }
 352                 return -EIO;
 353         }
 354
 355         /* otherwise, there is enough to get to the BCC */
 356         if (check_smb_hdr(smb))
 357                 return -EIO;
 358         clc_len = smbCalcSize(smb);
 359
 360         if (4 + rfclen != total_read) {
 361                 cifs_dbg(VFS, "Length read does not match RFC1001 length %d\n",
 362                          rfclen);
 363                 return -EIO;
 364         }
 365
 366         if (4 + rfclen != clc_len) {
 367                 __u16 mid = get_mid(smb);
 368                 /* check if bcc wrapped around for large read responses */
 369                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 370                         /* check if lengths match mod 64K */
 371                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 372                                 return 0; /* bcc wrapped */
 373                 }
 374                 cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 375                          clc_len, 4 + rfclen, mid);
 376
 377                 if (4 + rfclen < clc_len) {
 378                         cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 379                                  rfclen, mid);
 380                         return -EIO;
 381                 } else if (rfclen > clc_len + 512) {
 382                         /*
 383                          * Some servers (Windows XP in particular) send more
 384                          * data than the lengths in the SMB packet would
 385                          * indicate on certain calls (byte range locks and
 386                          * trans2 find first calls in particular). While the
 387                          * client can handle such a frame by ignoring the
 388                          * trailing data, we choose limit the amount of extra
 389                          * data to 512 bytes.
 390                          */
 391                         cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 392                                  rfclen, mid);
 393                         return -EIO;
 394                 }
 395         }
 396         return 0;
 397 }
 398
 399 bool
 400 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 401 {
 402         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 403         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 404         struct TCP_Server_Info *pserver;
 405         struct cifs_ses *ses;
 406         struct cifs_tcon *tcon;
 407         struct cifsInodeInfo *pCifsInode;
 408         struct cifsFileInfo *netfile;
 409
 410         cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 411         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 412            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 413                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 414                         (struct smb_com_transaction_change_notify_rsp *)buf;
 415                 struct file_notify_information *pnotify;
 416                 __u32 data_offset = 0;
 417                 size_t len = srv->total_read - sizeof(pSMBr->hdr.smb_buf_length);
 418
 419                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 420                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 421
 422                         if (data_offset >
 423                             len - sizeof(struct file_notify_information)) {
 424                                 cifs_dbg(FYI, "Invalid data_offset %u\n",
 425                                          data_offset);
 426                                 return true;
 427                         }
 428                         pnotify = (struct file_notify_information *)
 429                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 430                         cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 431                                  pnotify->FileName, pnotify->Action);
 432                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 433                                 sizeof(struct smb_hdr)+60); */
 434                         return true;
 435                 }
 436                 if (pSMBr->hdr.Status.CifsError) {
 437                         cifs_dbg(FYI, "notify err 0x%x\n",
 438                                  pSMBr->hdr.Status.CifsError);
 439                         return true;
 440                 }
 441                 return false;
 442         }
 443         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 444                 return false;
 445         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 446                 /* no sense logging error on invalid handle on oplock
 447                    break - harmless race between close request and oplock
 448                    break response is expected from time to time writing out
 449                    large dirty files cached on the client */
 450                 if ((NT_STATUS_INVALID_HANDLE) ==
 451                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 452                         cifs_dbg(FYI, "Invalid handle on oplock break\n");
 453                         return true;
 454                 } else if (ERRbadfid ==
 455                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 456                         return true;
 457                 } else {
 458                         return false; /* on valid oplock brk we get "request" */
 459                 }
 460         }
 461         if (pSMB->hdr.WordCount != 8)
 462                 return false;
 463
 464         cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 465                  pSMB->LockType, pSMB->OplockLevel);
 466         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 467                 return false;
 468
 469         /* If server is a channel, select the primary channel */
 470         pserver = CIFS_SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
 471
 472         /* look up tcon based on tid & uid */
 473         spin_lock(&cifs_tcp_ses_lock);
 474         list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 475                 list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 476                         if (tcon->tid != buf->Tid)
 477                                 continue;
 478
 479                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 480                         spin_lock(&tcon->open_file_lock);
 481                         list_for_each_entry(netfile, &tcon->openFileList, tlist) {
 482                                 if (pSMB->Fid != netfile->fid.netfid)
 483                                         continue;
 484
 485                                 cifs_dbg(FYI, "file id match, oplock break\n");
 486                                 pCifsInode = CIFS_I(d_inode(netfile->dentry));
 487
 488                                 set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 489                                         &pCifsInode->flags);
 490
 491                                 netfile->oplock_epoch = 0;
 492                                 netfile->oplock_level = pSMB->OplockLevel;
 493                                 netfile->oplock_break_cancelled = false;
 494                                 cifs_queue_oplock_break(netfile);
 495
 496                                 spin_unlock(&tcon->open_file_lock);
 497                                 spin_unlock(&cifs_tcp_ses_lock);
 498                                 return true;
 499                         }
 500                         spin_unlock(&tcon->open_file_lock);
 501                         spin_unlock(&cifs_tcp_ses_lock);
 502                         cifs_dbg(FYI, "No matching file for oplock break\n");
 503                         return true;
 504                 }
 505         }
 506         spin_unlock(&cifs_tcp_ses_lock);
 507         cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 508         return true;
 509 }
 510
 511 void
 512 dump_smb(void *buf, int smb_buf_length)
 513 {
 514         if (traceSMB == 0)
 515                 return;
 516
 517         print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 518                        smb_buf_length, true);
 519 }
 520
 521 void
 522 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 523 {
 524         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 525                 struct cifs_tcon *tcon = NULL;
 526
 527                 if (cifs_sb->master_tlink)
 528                         tcon = cifs_sb_master_tcon(cifs_sb);
 529
 530                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 531                 cifs_sb->mnt_cifs_serverino_autodisabled = true;
 532                 cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 533                          tcon ? tcon->tree_name : "new server");
 534                 cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 535                 cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 536
 537         }
 538 }
 539
 540 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 541 {
 542         oplock &= 0xF;
 543
 544         if (oplock == OPLOCK_EXCLUSIVE) {
 545                 cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 546                 cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 547                          &cinode->netfs.inode);
 548         } else if (oplock == OPLOCK_READ) {
 549                 cinode->oplock = CIFS_CACHE_READ_FLG;
 550                 cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 551                          &cinode->netfs.inode);
 552         } else
 553                 cinode->oplock = 0;
 554 }
 555
 556 /*
 557  * We wait for oplock breaks to be processed before we attempt to perform
 558  * writes.
 559  */
 560 int cifs_get_writer(struct cifsInodeInfo *cinode)
 561 {
 562         int rc;
 563
 564 start:
 565         rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 566                          TASK_KILLABLE);
 567         if (rc)
 568                 return rc;
 569
 570         spin_lock(&cinode->writers_lock);
 571         if (!cinode->writers)
 572                 set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 573         cinode->writers++;
 574         /* Check to see if we have started servicing an oplock break */
 575         if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 576                 cinode->writers--;
 577                 if (cinode->writers == 0) {
 578                         clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 579                         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 580                 }
 581                 spin_unlock(&cinode->writers_lock);
 582                 goto start;
 583         }
 584         spin_unlock(&cinode->writers_lock);
 585         return 0;
 586 }
 587
 588 void cifs_put_writer(struct cifsInodeInfo *cinode)
 589 {
 590         spin_lock(&cinode->writers_lock);
 591         cinode->writers--;
 592         if (cinode->writers == 0) {
 593                 clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 594                 wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 595         }
 596         spin_unlock(&cinode->writers_lock);
 597 }
 598
 599 /**
 600  * cifs_queue_oplock_break - queue the oplock break handler for cfile
 601  * @cfile: The file to break the oplock on
 602  *
 603  * This function is called from the demultiplex thread when it
 604  * receives an oplock break for @cfile.
 605  *
 606  * Assumes the tcon->open_file_lock is held.
 607  * Assumes cfile->file_info_lock is NOT held.
 608  */
 609 void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 610 {
 611         /*
 612          * Bump the handle refcount now while we hold the
 613          * open_file_lock to enforce the validity of it for the oplock
 614          * break handler. The matching put is done at the end of the
 615          * handler.
 616          */
 617         cifsFileInfo_get(cfile);
 618
 619         queue_work(cifsoplockd_wq, &cfile->oplock_break);
 620 }
 621
 622 void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 623 {
 624         clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 625         wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 626 }
 627
 628 bool
 629 backup_cred(struct cifs_sb_info *cifs_sb)
 630 {
 631         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 632                 if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
 633                         return true;
 634         }
 635         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 636                 if (in_group_p(cifs_sb->ctx->backupgid))
 637                         return true;
 638         }
 639
 640         return false;
 641 }
 642
 643 void
 644 cifs_del_pending_open(struct cifs_pending_open *open)
 645 {
 646         spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 647         list_del(&open->olist);
 648         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 649 }
 650
 651 void
 652 cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 653                              struct cifs_pending_open *open)
 654 {
 655         memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 656         open->oplock = CIFS_OPLOCK_NO_CHANGE;
 657         open->tlink = tlink;
 658         fid->pending_open = open;
 659         list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 660 }
 661
 662 void
 663 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 664                       struct cifs_pending_open *open)
 665 {
 666         spin_lock(&tlink_tcon(tlink)->open_file_lock);
 667         cifs_add_pending_open_locked(fid, tlink, open);
 668         spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 669 }
 670
 671 /*
 672  * Critical section which runs after acquiring deferred_lock.
 673  * As there is no reference count on cifs_deferred_close, pdclose
 674  * should not be used outside deferred_lock.
 675  */
 676 bool
 677 cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
 678 {
 679         struct cifs_deferred_close *dclose;
 680
 681         list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
 682                 if ((dclose->netfid == cfile->fid.netfid) &&
 683                         (dclose->persistent_fid == cfile->fid.persistent_fid) &&
 684                         (dclose->volatile_fid == cfile->fid.volatile_fid)) {
 685                         *pdclose = dclose;
 686                         return true;
 687                 }
 688         }
 689         return false;
 690 }
 691
 692 /*
 693  * Critical section which runs after acquiring deferred_lock.
 694  */
 695 void
 696 cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
 697 {
 698         bool is_deferred = false;
 699         struct cifs_deferred_close *pdclose;
 700
 701         is_deferred = cifs_is_deferred_close(cfile, &pdclose);
 702         if (is_deferred) {
 703                 kfree(dclose);
 704                 return;
 705         }
 706
 707         dclose->tlink = cfile->tlink;
 708         dclose->netfid = cfile->fid.netfid;
 709         dclose->persistent_fid = cfile->fid.persistent_fid;
 710         dclose->volatile_fid = cfile->fid.volatile_fid;
 711         list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
 712 }
 713
 714 /*
 715  * Critical section which runs after acquiring deferred_lock.
 716  */
 717 void
 718 cifs_del_deferred_close(struct cifsFileInfo *cfile)
 719 {
 720         bool is_deferred = false;
 721         struct cifs_deferred_close *dclose;
 722
 723         is_deferred = cifs_is_deferred_close(cfile, &dclose);
 724         if (!is_deferred)
 725                 return;
 726         list_del(&dclose->dlist);
 727         kfree(dclose);
 728 }
 729
 730 void
 731 cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
 732 {
 733         struct cifsFileInfo *cfile = NULL;
 734         struct file_list *tmp_list, *tmp_next_list;
 735         struct list_head file_head;
 736
 737         if (cifs_inode == NULL)
 738                 return;
 739
 740         INIT_LIST_HEAD(&file_head);
 741         spin_lock(&cifs_inode->open_file_lock);
 742         list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
 743                 if (delayed_work_pending(&cfile->deferred)) {
 744                         if (cancel_delayed_work(&cfile->deferred)) {
 745                                 spin_lock(&cifs_inode->deferred_lock);
 746                                 cifs_del_deferred_close(cfile);
 747                                 spin_unlock(&cifs_inode->deferred_lock);
 748
 749                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 750                                 if (tmp_list == NULL)
 751                                         break;
 752                                 tmp_list->cfile = cfile;
 753                                 list_add_tail(&tmp_list->list, &file_head);
 754                         }
 755                 }
 756         }
 757         spin_unlock(&cifs_inode->open_file_lock);
 758
 759         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 760                 _cifsFileInfo_put(tmp_list->cfile, false, false);
 761                 list_del(&tmp_list->list);
 762                 kfree(tmp_list);
 763         }
 764 }
 765
 766 void
 767 cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 768 {
 769         struct cifsFileInfo *cfile;
 770         struct file_list *tmp_list, *tmp_next_list;
 771         struct list_head file_head;
 772
 773         INIT_LIST_HEAD(&file_head);
 774         spin_lock(&tcon->open_file_lock);
 775         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 776                 if (delayed_work_pending(&cfile->deferred)) {
 777                         if (cancel_delayed_work(&cfile->deferred)) {
 778                                 spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 779                                 cifs_del_deferred_close(cfile);
 780                                 spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 781
 782                                 tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 783                                 if (tmp_list == NULL)
 784                                         break;
 785                                 tmp_list->cfile = cfile;
 786                                 list_add_tail(&tmp_list->list, &file_head);
 787                         }
 788                 }
 789         }
 790         spin_unlock(&tcon->open_file_lock);
 791
 792         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 793                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 794                 list_del(&tmp_list->list);
 795                 kfree(tmp_list);
 796         }
 797 }
 798 void
 799 cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon, const char *path)
 800 {
 801         struct cifsFileInfo *cfile;
 802         struct file_list *tmp_list, *tmp_next_list;
 803         struct list_head file_head;
 804         void *page;
 805         const char *full_path;
 806
 807         INIT_LIST_HEAD(&file_head);
 808         page = alloc_dentry_path();
 809         spin_lock(&tcon->open_file_lock);
 810         list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 811                 full_path = build_path_from_dentry(cfile->dentry, page);
 812                 if (strstr(full_path, path)) {
 813                         if (delayed_work_pending(&cfile->deferred)) {
 814                                 if (cancel_delayed_work(&cfile->deferred)) {
 815                                         spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 816                                         cifs_del_deferred_close(cfile);
 817                                         spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 818
 819                                         tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 820                                         if (tmp_list == NULL)
 821                                                 break;
 822                                         tmp_list->cfile = cfile;
 823                                         list_add_tail(&tmp_list->list, &file_head);
 824                                 }
 825                         }
 826                 }
 827         }
 828         spin_unlock(&tcon->open_file_lock);
 829
 830         list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 831                 _cifsFileInfo_put(tmp_list->cfile, true, false);
 832                 list_del(&tmp_list->list);
 833                 kfree(tmp_list);
 834         }
 835         free_dentry_path(page);
 836 }
 837
 838 /* parses DFS referral V3 structure
 839  * caller is responsible for freeing target_nodes
 840  * returns:
 841  * - on success - 0
 842  * - on failure - errno
 843  */
 844 int
 845 parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 846                     unsigned int *num_of_nodes,
 847                     struct dfs_info3_param **target_nodes,
 848                     const struct nls_table *nls_codepage, int remap,
 849                     const char *searchName, bool is_unicode)
 850 {
 851         int i, rc = 0;
 852         char *data_end;
 853         struct dfs_referral_level_3 *ref;
 854
 855         *num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 856
 857         if (*num_of_nodes < 1) {
 858                 cifs_dbg(VFS, "num_referrals: must be at least > 0, but we get num_referrals = %d\n",
 859                          *num_of_nodes);
 860                 rc = -EINVAL;
 861                 goto parse_DFS_referrals_exit;
 862         }
 863
 864         ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 865         if (ref->VersionNumber != cpu_to_le16(3)) {
 866                 cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 867                          le16_to_cpu(ref->VersionNumber));
 868                 rc = -EINVAL;
 869                 goto parse_DFS_referrals_exit;
 870         }
 871
 872         /* get the upper boundary of the resp buffer */
 873         data_end = (char *)rsp + rsp_size;
 874
 875         cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
 876                  *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
 877
 878         *target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
 879                                 GFP_KERNEL);
 880         if (*target_nodes == NULL) {
 881                 rc = -ENOMEM;
 882                 goto parse_DFS_referrals_exit;
 883         }
 884
 885         /* collect necessary data from referrals */
 886         for (i = 0; i < *num_of_nodes; i++) {
 887                 char *temp;
 888                 int max_len;
 889                 struct dfs_info3_param *node = (*target_nodes)+i;
 890
 891                 node->flags = le32_to_cpu(rsp->DFSFlags);
 892                 if (is_unicode) {
 893                         __le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
 894                                                 GFP_KERNEL);
 895                         if (tmp == NULL) {
 896                                 rc = -ENOMEM;
 897                                 goto parse_DFS_referrals_exit;
 898                         }
 899                         cifsConvertToUTF16((__le16 *) tmp, searchName,
 900                                            PATH_MAX, nls_codepage, remap);
 901                         node->path_consumed = cifs_utf16_bytes(tmp,
 902                                         le16_to_cpu(rsp->PathConsumed),
 903                                         nls_codepage);
 904                         kfree(tmp);
 905                 } else
 906                         node->path_consumed = le16_to_cpu(rsp->PathConsumed);
 907
 908                 node->server_type = le16_to_cpu(ref->ServerType);
 909                 node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
 910
 911                 /* copy DfsPath */
 912                 temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
 913                 max_len = data_end - temp;
 914                 node->path_name = cifs_strndup_from_utf16(temp, max_len,
 915                                                 is_unicode, nls_codepage);
 916                 if (!node->path_name) {
 917                         rc = -ENOMEM;
 918                         goto parse_DFS_referrals_exit;
 919                 }
 920
 921                 /* copy link target UNC */
 922                 temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
 923                 max_len = data_end - temp;
 924                 node->node_name = cifs_strndup_from_utf16(temp, max_len,
 925                                                 is_unicode, nls_codepage);
 926                 if (!node->node_name) {
 927                         rc = -ENOMEM;
 928                         goto parse_DFS_referrals_exit;
 929                 }
 930
 931                 node->ttl = le32_to_cpu(ref->TimeToLive);
 932
 933                 ref++;
 934         }
 935
 936 parse_DFS_referrals_exit:
 937         if (rc) {
 938                 free_dfs_info_array(*target_nodes, *num_of_nodes);
 939                 *target_nodes = NULL;
 940                 *num_of_nodes = 0;
 941         }
 942         return rc;
 943 }
 944
 945 struct cifs_aio_ctx *
 946 cifs_aio_ctx_alloc(void)
 947 {
 948         struct cifs_aio_ctx *ctx;
 949
 950         /*
 951          * Must use kzalloc to initialize ctx->bv to NULL and ctx->direct_io
 952          * to false so that we know when we have to unreference pages within
 953          * cifs_aio_ctx_release()
 954          */
 955         ctx = kzalloc(sizeof(struct cifs_aio_ctx), GFP_KERNEL);
 956         if (!ctx)
 957                 return NULL;
 958
 959         INIT_LIST_HEAD(&ctx->list);
 960         mutex_init(&ctx->aio_mutex);
 961         init_completion(&ctx->done);
 962         kref_init(&ctx->refcount);
 963         return ctx;
 964 }
 965
 966 void
 967 cifs_aio_ctx_release(struct kref *refcount)
 968 {
 969         struct cifs_aio_ctx *ctx = container_of(refcount,
 970                                         struct cifs_aio_ctx, refcount);
 971
 972         cifsFileInfo_put(ctx->cfile);
 973
 974         /*
 975          * ctx->bv is only set if setup_aio_ctx_iter() was call successfuly
 976          * which means that iov_iter_get_pages() was a success and thus that
 977          * we have taken reference on pages.
 978          */
 979         if (ctx->bv) {
 980                 unsigned i;
 981
 982                 for (i = 0; i < ctx->npages; i++) {
 983                         if (ctx->should_dirty)
 984                                 set_page_dirty(ctx->bv[i].bv_page);
 985                         put_page(ctx->bv[i].bv_page);
 986                 }
 987                 kvfree(ctx->bv);
 988         }
 989
 990         kfree(ctx);
 991 }
 992
 993 #define CIFS_AIO_KMALLOC_LIMIT (1024 * 1024)
 994
 995 int
 996 setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 997 {
 998         ssize_t rc;
 999         unsigned int cur_npages;
1000         unsigned int npages = 0;
1001         unsigned int i;
1002         size_t len;
1003         size_t count = iov_iter_count(iter);
1004         unsigned int saved_len;
1005         size_t start;
1006         unsigned int max_pages = iov_iter_npages(iter, INT_MAX);
1007         struct page **pages = NULL;
1008         struct bio_vec *bv = NULL;
1009
1010         if (iov_iter_is_kvec(iter)) {
1011                 memcpy(&ctx->iter, iter, sizeof(*iter));
1012                 ctx->len = count;
1013                 iov_iter_advance(iter, count);
1014                 return 0;
1015         }
1016
1017         if (array_size(max_pages, sizeof(*bv)) <= CIFS_AIO_KMALLOC_LIMIT)
1018                 bv = kmalloc_array(max_pages, sizeof(*bv), GFP_KERNEL);
1019
1020         if (!bv) {
1021                 bv = vmalloc(array_size(max_pages, sizeof(*bv)));
1022                 if (!bv)
1023                         return -ENOMEM;
1024         }
1025
1026         if (array_size(max_pages, sizeof(*pages)) <= CIFS_AIO_KMALLOC_LIMIT)
1027                 pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
1028
1029         if (!pages) {
1030                 pages = vmalloc(array_size(max_pages, sizeof(*pages)));
1031                 if (!pages) {
1032                         kvfree(bv);
1033                         return -ENOMEM;
1034                 }
1035         }
1036
1037         saved_len = count;
1038
1039         while (count && npages < max_pages) {
1040                 rc = iov_iter_get_pages2(iter, pages, count, max_pages, &start);
1041                 if (rc < 0) {
1042                         cifs_dbg(VFS, "Couldn't get user pages (rc=%zd)\n", rc);
1043                         break;
1044                 }
1045
1046                 if (rc > count) {
1047                         cifs_dbg(VFS, "get pages rc=%zd more than %zu\n", rc,
1048                                  count);
1049                         break;
1050                 }
1051
1052                 count -= rc;
1053                 rc += start;
1054                 cur_npages = DIV_ROUND_UP(rc, PAGE_SIZE);
1055
1056                 if (npages + cur_npages > max_pages) {
1057                         cifs_dbg(VFS, "out of vec array capacity (%u vs %u)\n",
1058                                  npages + cur_npages, max_pages);
1059                         break;
1060                 }
1061
1062                 for (i = 0; i < cur_npages; i++) {
1063                         len = rc > PAGE_SIZE ? PAGE_SIZE : rc;
1064                         bv[npages + i].bv_page = pages[i];
1065                         bv[npages + i].bv_offset = start;
1066                         bv[npages + i].bv_len = len - start;
1067                         rc -= len;
1068                         start = 0;
1069                 }
1070
1071                 npages += cur_npages;
1072         }
1073
1074         kvfree(pages);
1075         ctx->bv = bv;
1076         ctx->len = saved_len - count;
1077         ctx->npages = npages;
1078         iov_iter_bvec(&ctx->iter, rw, ctx->bv, npages, ctx->len);
1079         return 0;
1080 }
1081
1082 /**
1083  * cifs_alloc_hash - allocate hash and hash context together
1084  * @name: The name of the crypto hash algo
1085  * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1086  *
1087  * The caller has to make sure @sdesc is initialized to either NULL or
1088  * a valid context. It can be freed via cifs_free_hash().
1089  */
1090 int
1091 cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1092 {
1093         int rc = 0;
1094         struct crypto_shash *alg = NULL;
1095
1096         if (*sdesc)
1097                 return 0;
1098
1099         alg = crypto_alloc_shash(name, 0, 0);
1100         if (IS_ERR(alg)) {
1101                 cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1102                 rc = PTR_ERR(alg);
1103                 *sdesc = NULL;
1104                 return rc;
1105         }
1106
1107         *sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1108         if (*sdesc == NULL) {
1109                 cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1110                 crypto_free_shash(alg);
1111                 return -ENOMEM;
1112         }
1113
1114         (*sdesc)->tfm = alg;
1115         return 0;
1116 }
1117
1118 /**
1119  * cifs_free_hash - free hash and hash context together
1120  * @sdesc: Where to find the pointer to the hash TFM
1121  *
1122  * Freeing a NULL descriptor is safe.
1123  */
1124 void
1125 cifs_free_hash(struct shash_desc **sdesc)
1126 {
1127         if (unlikely(!sdesc) || !*sdesc)
1128                 return;
1129
1130         if ((*sdesc)->tfm) {
1131                 crypto_free_shash((*sdesc)->tfm);
1132                 (*sdesc)->tfm = NULL;
1133         }
1134
1135         kfree_sensitive(*sdesc);
1136         *sdesc = NULL;
1137 }
1138
1139 /**
1140  * rqst_page_get_length - obtain the length and offset for a page in smb_rqst
1141  * @rqst: The request descriptor
1142  * @page: The index of the page to query
1143  * @len: Where to store the length for this page:
1144  * @offset: Where to store the offset for this page
1145  */
1146 void rqst_page_get_length(const struct smb_rqst *rqst, unsigned int page,
1147                           unsigned int *len, unsigned int *offset)
1148 {
1149         *len = rqst->rq_pagesz;
1150         *offset = (page == 0) ? rqst->rq_offset : 0;
1151
1152         if (rqst->rq_npages == 1 || page == rqst->rq_npages-1)
1153                 *len = rqst->rq_tailsz;
1154         else if (page == 0)
1155                 *len = rqst->rq_pagesz - rqst->rq_offset;
1156 }
1157
1158 void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1159 {
1160         const char *end;
1161
1162         /* skip initial slashes */
1163         while (*unc && (*unc == '\\' || *unc == '/'))
1164                 unc++;
1165
1166         end = unc;
1167
1168         while (*end && !(*end == '\\' || *end == '/'))
1169                 end++;
1170
1171         *h = unc;
1172         *len = end - unc;
1173 }
1174
1175 /**
1176  * copy_path_name - copy src path to dst, possibly truncating
1177  * @dst: The destination buffer
1178  * @src: The source name
1179  *
1180  * returns number of bytes written (including trailing nul)
1181  */
1182 int copy_path_name(char *dst, const char *src)
1183 {
1184         int name_len;
1185
1186         /*
1187          * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1188          * will truncate and strlen(dst) will be PATH_MAX-1
1189          */
1190         name_len = strscpy(dst, src, PATH_MAX);
1191         if (WARN_ON_ONCE(name_len < 0))
1192                 name_len = PATH_MAX-1;
1193
1194         /* we count the trailing nul */
1195         name_len++;
1196         return name_len;
1197 }
1198
1199 struct super_cb_data {
1200         void *data;
1201         struct super_block *sb;
1202 };
1203
1204 static void tcp_super_cb(struct super_block *sb, void *arg)
1205 {
1206         struct super_cb_data *sd = arg;
1207         struct TCP_Server_Info *server = sd->data;
1208         struct cifs_sb_info *cifs_sb;
1209         struct cifs_tcon *tcon;
1210
1211         if (sd->sb)
1212                 return;
1213
1214         cifs_sb = CIFS_SB(sb);
1215         tcon = cifs_sb_master_tcon(cifs_sb);
1216         if (tcon->ses->server == server)
1217                 sd->sb = sb;
1218 }
1219
1220 static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1221                                             void *data)
1222 {
1223         struct super_cb_data sd = {
1224                 .data = data,
1225                 .sb = NULL,
1226         };
1227         struct file_system_type **fs_type = (struct file_system_type *[]) {
1228                 &cifs_fs_type, &smb3_fs_type, NULL,
1229         };
1230
1231         for (; *fs_type; fs_type++) {
1232                 iterate_supers_type(*fs_type, f, &sd);
1233                 if (sd.sb) {
1234                         /*
1235                          * Grab an active reference in order to prevent automounts (DFS links)
1236                          * of expiring and then freeing up our cifs superblock pointer while
1237                          * we're doing failover.
1238                          */
1239                         cifs_sb_active(sd.sb);
1240                         return sd.sb;
1241                 }
1242         }
1243         return ERR_PTR(-EINVAL);
1244 }
1245
1246 static void __cifs_put_super(struct super_block *sb)
1247 {
1248         if (!IS_ERR_OR_NULL(sb))
1249                 cifs_sb_deactive(sb);
1250 }
1251
1252 struct super_block *cifs_get_tcp_super(struct TCP_Server_Info *server)
1253 {
1254         return __cifs_get_super(tcp_super_cb, server);
1255 }
1256
1257 void cifs_put_tcp_super(struct super_block *sb)
1258 {
1259         __cifs_put_super(sb);
1260 }
1261
1262 #ifdef CONFIG_CIFS_DFS_UPCALL
1263 int match_target_ip(struct TCP_Server_Info *server,
1264                     const char *share, size_t share_len,
1265                     bool *result)
1266 {
1267         int rc;
1268         char *target, *tip = NULL;
1269         struct sockaddr tipaddr;
1270
1271         *result = false;
1272
1273         target = kzalloc(share_len + 3, GFP_KERNEL);
1274         if (!target) {
1275                 rc = -ENOMEM;
1276                 goto out;
1277         }
1278
1279         scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
1280
1281         cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
1282
1283         rc = dns_resolve_server_name_to_ip(target, &tip, NULL);
1284         if (rc < 0)
1285                 goto out;
1286
1287         cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
1288
1289         if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
1290                 cifs_dbg(VFS, "%s: failed to convert target ip address\n",
1291                          __func__);
1292                 rc = -EINVAL;
1293                 goto out;
1294         }
1295
1296         *result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
1297                                     &tipaddr);
1298         cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
1299         rc = 0;
1300
1301 out:
1302         kfree(target);
1303         kfree(tip);
1304
1305         return rc;
1306 }
1307
1308 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1309 {
1310         kfree(cifs_sb->prepath);
1311
1312         if (prefix && *prefix) {
1313                 cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1314                 if (!cifs_sb->prepath)
1315                         return -ENOMEM;
1316
1317                 convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1318         } else
1319                 cifs_sb->prepath = NULL;
1320
1321         cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1322         return 0;
1323 }
1324
1325 /*
1326  * Handle weird Windows SMB server behaviour. It responds with
1327  * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1328  * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1329  * non-ASCII unicode symbols.
1330  */
1331 int cifs_inval_name_dfs_link_error(const unsigned int xid,
1332                                    struct cifs_tcon *tcon,
1333                                    struct cifs_sb_info *cifs_sb,
1334                                    const char *full_path,
1335                                    bool *islink)
1336 {
1337         struct cifs_ses *ses = tcon->ses;
1338         size_t len;
1339         char *path;
1340         char *ref_path;
1341
1342         *islink = false;
1343
1344         /*
1345          * Fast path - skip check when @full_path doesn't have a prefix path to
1346          * look up or tcon is not DFS.
1347          */
1348         if (strlen(full_path) < 2 || !cifs_sb ||
1349             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1350             !is_tcon_dfs(tcon) || !ses->server->origin_fullpath)
1351                 return 0;
1352
1353         /*
1354          * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1355          * to get a referral to figure out whether it is an DFS link.
1356          */
1357         len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1358         path = kmalloc(len, GFP_KERNEL);
1359         if (!path)
1360                 return -ENOMEM;
1361
1362         scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1363         ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1364                                             cifs_remap(cifs_sb));
1365         kfree(path);
1366
1367         if (IS_ERR(ref_path)) {
1368                 if (PTR_ERR(ref_path) != -EINVAL)
1369                         return PTR_ERR(ref_path);
1370         } else {
1371                 struct dfs_info3_param *refs = NULL;
1372                 int num_refs = 0;
1373
1374                 /*
1375                  * XXX: we are not using dfs_cache_find() here because we might
1376                  * end filling all the DFS cache and thus potentially
1377                  * removing cached DFS targets that the client would eventually
1378                  * need during failover.
1379                  */
1380                 if (ses->server->ops->get_dfs_refer &&
1381                     !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1382                                                      &num_refs, cifs_sb->local_nls,
1383                                                      cifs_remap(cifs_sb)))
1384                         *islink = refs[0].server_type == DFS_TYPE_LINK;
1385                 free_dfs_info_array(refs, num_refs);
1386                 kfree(ref_path);
1387         }
1388         return 0;
1389 }
1390 #endif
1391
1392 int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1393 {
1394         int timeout = 10;
1395         int rc;
1396
1397         spin_lock(&server->srv_lock);
1398         if (server->tcpStatus != CifsNeedReconnect) {
1399                 spin_unlock(&server->srv_lock);
1400                 return 0;
1401         }
1402         timeout *= server->nr_targets;
1403         spin_unlock(&server->srv_lock);
1404
1405         /*
1406          * Give demultiplex thread up to 10 seconds to each target available for
1407          * reconnect -- should be greater than cifs socket timeout which is 7
1408          * seconds.
1409          *
1410          * On "soft" mounts we wait once. Hard mounts keep retrying until
1411          * process is killed or server comes back on-line.
1412          */
1413         do {
1414                 rc = wait_event_interruptible_timeout(server->response_q,
1415                                                       (server->tcpStatus != CifsNeedReconnect),
1416                                                       timeout * HZ);
1417                 if (rc < 0) {
1418                         cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1419                                  __func__);
1420                         return -ERESTARTSYS;
1421                 }
1422
1423                 /* are we still trying to reconnect? */
1424                 spin_lock(&server->srv_lock);
1425                 if (server->tcpStatus != CifsNeedReconnect) {
1426                         spin_unlock(&server->srv_lock);
1427                         return 0;
1428                 }
1429                 spin_unlock(&server->srv_lock);
1430         } while (retry);
1431
1432         cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1433         return -EHOSTDOWN;
1434 }