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 "smb2proto.h"
  22#include "cifsfs.h"
  23#ifdef CONFIG_CIFS_DFS_UPCALL
  24#include "dns_resolve.h"
  25#include "dfs_cache.h"
  26#include "dfs.h"
  27#endif
  28#include "fs_context.h"
  29#include "cached_dir.h"
  30
  31struct tcon_list {
  32	struct list_head entry;
  33	struct cifs_tcon *tcon;
  34};
  35
  36/* The xid serves as a useful identifier for each incoming vfs request,
  37   in a similar way to the mid which is useful to track each sent smb,
  38   and CurrentXid can also provide a running counter (although it
  39   will eventually wrap past zero) of the total vfs operations handled
  40   since the cifs fs was mounted */
  41
  42unsigned int
  43_get_xid(void)
  44{
  45	unsigned int xid;
  46
  47	spin_lock(&GlobalMid_Lock);
  48	GlobalTotalActiveXid++;
  49
  50	/* keep high water mark for number of simultaneous ops in filesystem */
  51	if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  52		GlobalMaxActiveXid = GlobalTotalActiveXid;
  53	if (GlobalTotalActiveXid > 65000)
  54		cifs_dbg(FYI, "warning: more than 65000 requests active\n");
  55	xid = GlobalCurrentXid++;
  56	spin_unlock(&GlobalMid_Lock);
  57	return xid;
  58}
  59
  60void
  61_free_xid(unsigned int xid)
  62{
  63	spin_lock(&GlobalMid_Lock);
  64	/* if (GlobalTotalActiveXid == 0)
  65		BUG(); */
  66	GlobalTotalActiveXid--;
  67	spin_unlock(&GlobalMid_Lock);
  68}
  69
  70struct cifs_ses *
  71sesInfoAlloc(void)
  72{
  73	struct cifs_ses *ret_buf;
  74
  75	ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  76	if (ret_buf) {
  77		atomic_inc(&sesInfoAllocCount);
  78		spin_lock_init(&ret_buf->ses_lock);
  79		ret_buf->ses_status = SES_NEW;
  80		++ret_buf->ses_count;
  81		INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  82		INIT_LIST_HEAD(&ret_buf->tcon_list);
  83		mutex_init(&ret_buf->session_mutex);
  84		spin_lock_init(&ret_buf->iface_lock);
  85		INIT_LIST_HEAD(&ret_buf->iface_list);
  86		spin_lock_init(&ret_buf->chan_lock);
  87	}
  88	return ret_buf;
  89}
  90
  91void
  92sesInfoFree(struct cifs_ses *buf_to_free)
  93{
  94	struct cifs_server_iface *iface = NULL, *niface = NULL;
  95
  96	if (buf_to_free == NULL) {
  97		cifs_dbg(FYI, "Null buffer passed to sesInfoFree\n");
  98		return;
  99	}
 100
 101	unload_nls(buf_to_free->local_nls);
 102	atomic_dec(&sesInfoAllocCount);
 103	kfree(buf_to_free->serverOS);
 104	kfree(buf_to_free->serverDomain);
 105	kfree(buf_to_free->serverNOS);
 106	kfree_sensitive(buf_to_free->password);
 107	kfree_sensitive(buf_to_free->password2);
 108	kfree(buf_to_free->user_name);
 109	kfree(buf_to_free->domainName);
 110	kfree(buf_to_free->dns_dom);
 111	kfree_sensitive(buf_to_free->auth_key.response);
 112	spin_lock(&buf_to_free->iface_lock);
 113	list_for_each_entry_safe(iface, niface, &buf_to_free->iface_list,
 114				 iface_head)
 115		kref_put(&iface->refcount, release_iface);
 116	spin_unlock(&buf_to_free->iface_lock);
 117	kfree_sensitive(buf_to_free);
 118}
 119
 120struct cifs_tcon *
 121tcon_info_alloc(bool dir_leases_enabled, enum smb3_tcon_ref_trace trace)
 122{
 123	struct cifs_tcon *ret_buf;
 124	static atomic_t tcon_debug_id;
 125
 126	ret_buf = kzalloc(sizeof(*ret_buf), GFP_KERNEL);
 127	if (!ret_buf)
 128		return NULL;
 129
 130	if (dir_leases_enabled == true) {
 131		ret_buf->cfids = init_cached_dirs();
 132		if (!ret_buf->cfids) {
 133			kfree(ret_buf);
 134			return NULL;
 135		}
 136	}
 137	/* else ret_buf->cfids is already set to NULL above */
 138
 139	atomic_inc(&tconInfoAllocCount);
 140	ret_buf->status = TID_NEW;
 141	ret_buf->debug_id = atomic_inc_return(&tcon_debug_id);
 142	ret_buf->tc_count = 1;
 143	spin_lock_init(&ret_buf->tc_lock);
 144	INIT_LIST_HEAD(&ret_buf->openFileList);
 145	INIT_LIST_HEAD(&ret_buf->tcon_list);
 146	INIT_LIST_HEAD(&ret_buf->cifs_sb_list);
 147	spin_lock_init(&ret_buf->open_file_lock);
 148	spin_lock_init(&ret_buf->stat_lock);
 149	spin_lock_init(&ret_buf->sb_list_lock);
 150	atomic_set(&ret_buf->num_local_opens, 0);
 151	atomic_set(&ret_buf->num_remote_opens, 0);
 152	ret_buf->stats_from_time = ktime_get_real_seconds();
 153#ifdef CONFIG_CIFS_FSCACHE
 154	mutex_init(&ret_buf->fscache_lock);
 155#endif
 156	trace_smb3_tcon_ref(ret_buf->debug_id, ret_buf->tc_count, trace);
 157#ifdef CONFIG_CIFS_DFS_UPCALL
 158	INIT_LIST_HEAD(&ret_buf->dfs_ses_list);
 159#endif
 160	INIT_LIST_HEAD(&ret_buf->pending_opens);
 161	INIT_DELAYED_WORK(&ret_buf->query_interfaces,
 162			  smb2_query_server_interfaces);
 163#ifdef CONFIG_CIFS_DFS_UPCALL
 164	INIT_DELAYED_WORK(&ret_buf->dfs_cache_work, dfs_cache_refresh);
 165#endif
 166
 167	return ret_buf;
 168}
 169
 170void
 171tconInfoFree(struct cifs_tcon *tcon, enum smb3_tcon_ref_trace trace)
 172{
 173	if (tcon == NULL) {
 174		cifs_dbg(FYI, "Null buffer passed to tconInfoFree\n");
 175		return;
 176	}
 177	trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, trace);
 178	free_cached_dirs(tcon->cfids);
 179	atomic_dec(&tconInfoAllocCount);
 180	kfree(tcon->nativeFileSystem);
 181	kfree_sensitive(tcon->password);
 182	kfree(tcon->origin_fullpath);
 183	kfree(tcon);
 184}
 185
 186struct smb_hdr *
 187cifs_buf_get(void)
 188{
 189	struct smb_hdr *ret_buf = NULL;
 190	/*
 191	 * SMB2 header is bigger than CIFS one - no problems to clean some
 192	 * more bytes for CIFS.
 193	 */
 194	size_t buf_size = sizeof(struct smb2_hdr);
 195
 196	/*
 197	 * We could use negotiated size instead of max_msgsize -
 198	 * but it may be more efficient to always alloc same size
 199	 * albeit slightly larger than necessary and maxbuffersize
 200	 * defaults to this and can not be bigger.
 201	 */
 202	ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 203
 204	/* clear the first few header bytes */
 205	/* for most paths, more is cleared in header_assemble */
 206	memset(ret_buf, 0, buf_size + 3);
 207	atomic_inc(&buf_alloc_count);
 208#ifdef CONFIG_CIFS_STATS2
 209	atomic_inc(&total_buf_alloc_count);
 210#endif /* CONFIG_CIFS_STATS2 */
 211
 212	return ret_buf;
 213}
 214
 215void
 216cifs_buf_release(void *buf_to_free)
 217{
 218	if (buf_to_free == NULL) {
 219		/* cifs_dbg(FYI, "Null buffer passed to cifs_buf_release\n");*/
 220		return;
 221	}
 222	mempool_free(buf_to_free, cifs_req_poolp);
 223
 224	atomic_dec(&buf_alloc_count);
 225	return;
 226}
 227
 228struct smb_hdr *
 229cifs_small_buf_get(void)
 230{
 231	struct smb_hdr *ret_buf = NULL;
 232
 233/* We could use negotiated size instead of max_msgsize -
 234   but it may be more efficient to always alloc same size
 235   albeit slightly larger than necessary and maxbuffersize
 236   defaults to this and can not be bigger */
 237	ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 238	/* No need to clear memory here, cleared in header assemble */
 239	/*	memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 240	atomic_inc(&small_buf_alloc_count);
 241#ifdef CONFIG_CIFS_STATS2
 242	atomic_inc(&total_small_buf_alloc_count);
 243#endif /* CONFIG_CIFS_STATS2 */
 244
 245	return ret_buf;
 246}
 247
 248void
 249cifs_small_buf_release(void *buf_to_free)
 250{
 251
 252	if (buf_to_free == NULL) {
 253		cifs_dbg(FYI, "Null buffer passed to cifs_small_buf_release\n");
 254		return;
 255	}
 256	mempool_free(buf_to_free, cifs_sm_req_poolp);
 257
 258	atomic_dec(&small_buf_alloc_count);
 259	return;
 260}
 261
 262void
 263free_rsp_buf(int resp_buftype, void *rsp)
 264{
 265	if (resp_buftype == CIFS_SMALL_BUFFER)
 266		cifs_small_buf_release(rsp);
 267	else if (resp_buftype == CIFS_LARGE_BUFFER)
 268		cifs_buf_release(rsp);
 269}
 270
 271/* NB: MID can not be set if treeCon not passed in, in that
 272   case it is responsibility of caller to set the mid */
 273unsigned int
 274header_assemble(struct smb_hdr *buffer, char smb_command,
 275		const struct cifs_tcon *treeCon, int word_count
 276		/* length of fixed section (word count) in two byte units  */)
 277{
 278	unsigned int in_len;
 279	char *temp = (char *) buffer;
 280
 281	memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 282
 283	in_len = (2 * word_count) + sizeof(struct smb_hdr) +
 284		2 /* for bcc field itself */;
 285
 286	buffer->Protocol[0] = 0xFF;
 287	buffer->Protocol[1] = 'S';
 288	buffer->Protocol[2] = 'M';
 289	buffer->Protocol[3] = 'B';
 290	buffer->Command = smb_command;
 291	buffer->Flags = 0x00;	/* case sensitive */
 292	buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 293	buffer->Pid = cpu_to_le16((__u16)current->tgid);
 294	buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 295	if (treeCon) {
 296		buffer->Tid = treeCon->tid;
 297		if (treeCon->ses) {
 298			if (treeCon->ses->capabilities & CAP_UNICODE)
 299				buffer->Flags2 |= SMBFLG2_UNICODE;
 300			if (treeCon->ses->capabilities & CAP_STATUS32)
 301				buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 302
 303			/* Uid is not converted */
 304			buffer->Uid = treeCon->ses->Suid;
 305			if (treeCon->ses->server)
 306				buffer->Mid = get_next_mid(treeCon->ses->server);
 307		}
 308		if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 309			buffer->Flags2 |= SMBFLG2_DFS;
 310		if (treeCon->nocase)
 311			buffer->Flags  |= SMBFLG_CASELESS;
 312		if ((treeCon->ses) && (treeCon->ses->server))
 313			if (treeCon->ses->server->sign)
 314				buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 315	}
 316
 317/*  endian conversion of flags is now done just before sending */
 318	buffer->WordCount = (char) word_count;
 319	return in_len;
 320}
 321
 322static int
 323check_smb_hdr(struct smb_hdr *smb)
 324{
 325	/* does it have the right SMB "signature" ? */
 326	if (*(__le32 *) smb->Protocol != SMB1_PROTO_NUMBER) {
 327		cifs_dbg(VFS, "Bad protocol string signature header 0x%x\n",
 328			 *(unsigned int *)smb->Protocol);
 329		return 1;
 330	}
 331
 332	/* if it's a response then accept */
 333	if (smb->Flags & SMBFLG_RESPONSE)
 334		return 0;
 335
 336	/* only one valid case where server sends us request */
 337	if (smb->Command == SMB_COM_LOCKING_ANDX)
 338		return 0;
 339
 340	/*
 341	 * Windows NT server returns error resposne (e.g. STATUS_DELETE_PENDING
 342	 * or STATUS_OBJECT_NAME_NOT_FOUND or ERRDOS/ERRbadfile or any other)
 343	 * for some TRANS2 requests without the RESPONSE flag set in header.
 344	 */
 345	if (smb->Command == SMB_COM_TRANSACTION2 && smb->Status.CifsError != 0)
 346		return 0;
 347
 348	cifs_dbg(VFS, "Server sent request, not response. mid=%u\n",
 349		 get_mid(smb));
 350	return 1;
 351}
 352
 353int
 354checkSMB(char *buf, unsigned int pdu_len, unsigned int total_read,
 355	 struct TCP_Server_Info *server)
 356{
 357	struct smb_hdr *smb = (struct smb_hdr *)buf;
 358	__u32 rfclen = pdu_len;
 359	__u32 clc_len;  /* calculated length */
 360	cifs_dbg(FYI, "checkSMB Length: 0x%x, smb_buf_length: 0x%x\n",
 361		 total_read, rfclen);
 362
 363	/* is this frame too small to even get to a BCC? */
 364	if (total_read < 2 + sizeof(struct smb_hdr)) {
 365		if ((total_read >= sizeof(struct smb_hdr) - 1)
 366			    && (smb->Status.CifsError != 0)) {
 367			/* it's an error return */
 368			smb->WordCount = 0;
 369			/* some error cases do not return wct and bcc */
 370			return 0;
 371		} else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 372				(smb->WordCount == 0)) {
 373			char *tmp = (char *)smb;
 374			/* Need to work around a bug in two servers here */
 375			/* First, check if the part of bcc they sent was zero */
 376			if (tmp[sizeof(struct smb_hdr)] == 0) {
 377				/* some servers return only half of bcc
 378				 * on simple responses (wct, bcc both zero)
 379				 * in particular have seen this on
 380				 * ulogoffX and FindClose. This leaves
 381				 * one byte of bcc potentially uninitialized
 382				 */
 383				/* zero rest of bcc */
 384				tmp[sizeof(struct smb_hdr)+1] = 0;
 385				return 0;
 386			}
 387			cifs_dbg(VFS, "rcvd invalid byte count (bcc)\n");
 388			return smb_EIO1(smb_eio_trace_rx_inv_bcc, tmp[sizeof(struct smb_hdr)]);
 389		} else {
 390			cifs_dbg(VFS, "Length less than smb header size\n");
 391			return smb_EIO2(smb_eio_trace_rx_too_short,
 392					total_read, smb->WordCount);
 393		}
 394	} else if (total_read < sizeof(*smb) + 2 * smb->WordCount) {
 395		cifs_dbg(VFS, "%s: can't read BCC due to invalid WordCount(%u)\n",
 396			 __func__, smb->WordCount);
 397		return smb_EIO2(smb_eio_trace_rx_check_rsp,
 398				total_read, 2 + sizeof(struct smb_hdr));
 399	}
 400
 401	/* otherwise, there is enough to get to the BCC */
 402	if (check_smb_hdr(smb))
 403		return smb_EIO1(smb_eio_trace_rx_rfc1002_magic, *(u32 *)smb->Protocol);
 404	clc_len = smbCalcSize(smb);
 405
 406	if (rfclen != total_read) {
 407		cifs_dbg(VFS, "Length read does not match RFC1001 length %d/%d\n",
 408			 rfclen, total_read);
 409		return smb_EIO2(smb_eio_trace_rx_check_rsp,
 410				total_read, rfclen);
 411	}
 412
 413	if (rfclen != clc_len) {
 414		__u16 mid = get_mid(smb);
 415		/* check if bcc wrapped around for large read responses */
 416		if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 417			/* check if lengths match mod 64K */
 418			if (((rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 419				return 0; /* bcc wrapped */
 420		}
 421		cifs_dbg(FYI, "Calculated size %u vs length %u mismatch for mid=%u\n",
 422			 clc_len, rfclen, mid);
 423
 424		if (rfclen < clc_len) {
 425			cifs_dbg(VFS, "RFC1001 size %u smaller than SMB for mid=%u\n",
 426				 rfclen, mid);
 427			return smb_EIO2(smb_eio_trace_rx_calc_len_too_big,
 428					rfclen, clc_len);
 429		} else if (rfclen > clc_len + 512) {
 430			/*
 431			 * Some servers (Windows XP in particular) send more
 432			 * data than the lengths in the SMB packet would
 433			 * indicate on certain calls (byte range locks and
 434			 * trans2 find first calls in particular). While the
 435			 * client can handle such a frame by ignoring the
 436			 * trailing data, we choose limit the amount of extra
 437			 * data to 512 bytes.
 438			 */
 439			cifs_dbg(VFS, "RFC1001 size %u more than 512 bytes larger than SMB for mid=%u\n",
 440				 rfclen, mid);
 441			return smb_EIO2(smb_eio_trace_rx_overlong,
 442					rfclen, clc_len + 512);
 443		}
 444	}
 445	return 0;
 446}
 447
 448bool
 449is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 450{
 451	struct smb_hdr *buf = (struct smb_hdr *)buffer;
 452	struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 453	struct TCP_Server_Info *pserver;
 454	struct cifs_ses *ses;
 455	struct cifs_tcon *tcon;
 456	struct cifsInodeInfo *pCifsInode;
 457	struct cifsFileInfo *netfile;
 458
 459	cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
 460	if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 461	   (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 462		struct smb_com_transaction_change_notify_rsp *pSMBr =
 463			(struct smb_com_transaction_change_notify_rsp *)buf;
 464		struct file_notify_information *pnotify;
 465		__u32 data_offset = 0;
 466		size_t len = srv->total_read - srv->pdu_size;
 467
 468		if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 469			data_offset = le32_to_cpu(pSMBr->DataOffset);
 470
 471			if (data_offset >
 472			    len - sizeof(struct file_notify_information)) {
 473				cifs_dbg(FYI, "Invalid data_offset %u\n",
 474					 data_offset);
 475				return true;
 476			}
 477			pnotify = (struct file_notify_information *)
 478				((char *)&pSMBr->hdr.Protocol + data_offset);
 479			cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
 480				 pnotify->FileName, pnotify->Action);
 481			/*   cifs_dump_mem("Rcvd notify Data: ",buf,
 482				sizeof(struct smb_hdr)+60); */
 483			return true;
 484		}
 485		if (pSMBr->hdr.Status.CifsError) {
 486			cifs_dbg(FYI, "notify err 0x%x\n",
 487				 pSMBr->hdr.Status.CifsError);
 488			return true;
 489		}
 490		return false;
 491	}
 492	if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 493		return false;
 494	if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 495		/* no sense logging error on invalid handle on oplock
 496		   break - harmless race between close request and oplock
 497		   break response is expected from time to time writing out
 498		   large dirty files cached on the client */
 499		if ((NT_STATUS_INVALID_HANDLE) ==
 500		   le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 501			cifs_dbg(FYI, "Invalid handle on oplock break\n");
 502			return true;
 503		} else if (ERRbadfid ==
 504		   le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 505			return true;
 506		} else {
 507			return false; /* on valid oplock brk we get "request" */
 508		}
 509	}
 510	if (pSMB->hdr.WordCount != 8)
 511		return false;
 512
 513	cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
 514		 pSMB->LockType, pSMB->OplockLevel);
 515	if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 516		return false;
 517
 518	/* If server is a channel, select the primary channel */
 519	pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;
 520
 521	/* look up tcon based on tid & uid */
 522	spin_lock(&cifs_tcp_ses_lock);
 523	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
 524		if (cifs_ses_exiting(ses))
 525			continue;
 526		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 527			if (tcon->tid != buf->Tid)
 528				continue;
 529
 530			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 531			spin_lock(&tcon->open_file_lock);
 532			list_for_each_entry(netfile, &tcon->openFileList, tlist) {
 533				if (pSMB->Fid != netfile->fid.netfid)
 534					continue;
 535
 536				cifs_dbg(FYI, "file id match, oplock break\n");
 537				pCifsInode = CIFS_I(d_inode(netfile->dentry));
 538
 539				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 540					&pCifsInode->flags);
 541
 542				netfile->oplock_epoch = 0;
 543				netfile->oplock_level = pSMB->OplockLevel;
 544				netfile->oplock_break_cancelled = false;
 545				cifs_queue_oplock_break(netfile);
 546
 547				spin_unlock(&tcon->open_file_lock);
 548				spin_unlock(&cifs_tcp_ses_lock);
 549				return true;
 550			}
 551			spin_unlock(&tcon->open_file_lock);
 552			spin_unlock(&cifs_tcp_ses_lock);
 553			cifs_dbg(FYI, "No matching file for oplock break\n");
 554			return true;
 555		}
 556	}
 557	spin_unlock(&cifs_tcp_ses_lock);
 558	cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 559	return true;
 560}
 561
 562void
 563dump_smb(void *buf, int smb_buf_length)
 564{
 565	if (traceSMB == 0)
 566		return;
 567
 568	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_NONE, 8, 2, buf,
 569		       smb_buf_length, true);
 570}
 571
 572void
 573cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 574{
 575	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 576		struct cifs_tcon *tcon = NULL;
 577
 578		if (cifs_sb->master_tlink)
 579			tcon = cifs_sb_master_tcon(cifs_sb);
 580
 581		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 582		cifs_sb->mnt_cifs_serverino_autodisabled = true;
 583		cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 584			 tcon ? tcon->tree_name : "new server");
 585		cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 586		cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
 587
 588	}
 589}
 590
 591void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 592{
 593	oplock &= 0xF;
 594
 595	if (oplock == OPLOCK_EXCLUSIVE) {
 596		cinode->oplock = CIFS_CACHE_WRITE_FLG | CIFS_CACHE_READ_FLG;
 597		cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
 598			 &cinode->netfs.inode);
 599	} else if (oplock == OPLOCK_READ) {
 600		cinode->oplock = CIFS_CACHE_READ_FLG;
 601		cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
 602			 &cinode->netfs.inode);
 603	} else
 604		cinode->oplock = 0;
 605}
 606
 607/*
 608 * We wait for oplock breaks to be processed before we attempt to perform
 609 * writes.
 610 */
 611int cifs_get_writer(struct cifsInodeInfo *cinode)
 612{
 613	int rc;
 614
 615start:
 616	rc = wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK,
 617			 TASK_KILLABLE);
 618	if (rc)
 619		return rc;
 620
 621	spin_lock(&cinode->writers_lock);
 622	if (!cinode->writers)
 623		set_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 624	cinode->writers++;
 625	/* Check to see if we have started servicing an oplock break */
 626	if (test_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags)) {
 627		cinode->writers--;
 628		if (cinode->writers == 0) {
 629			clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 630			wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 631		}
 632		spin_unlock(&cinode->writers_lock);
 633		goto start;
 634	}
 635	spin_unlock(&cinode->writers_lock);
 636	return 0;
 637}
 638
 639void cifs_put_writer(struct cifsInodeInfo *cinode)
 640{
 641	spin_lock(&cinode->writers_lock);
 642	cinode->writers--;
 643	if (cinode->writers == 0) {
 644		clear_bit(CIFS_INODE_PENDING_WRITERS, &cinode->flags);
 645		wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS);
 646	}
 647	spin_unlock(&cinode->writers_lock);
 648}
 649
 650/**
 651 * cifs_queue_oplock_break - queue the oplock break handler for cfile
 652 * @cfile: The file to break the oplock on
 653 *
 654 * This function is called from the demultiplex thread when it
 655 * receives an oplock break for @cfile.
 656 *
 657 * Assumes the tcon->open_file_lock is held.
 658 * Assumes cfile->file_info_lock is NOT held.
 659 */
 660void cifs_queue_oplock_break(struct cifsFileInfo *cfile)
 661{
 662	/*
 663	 * Bump the handle refcount now while we hold the
 664	 * open_file_lock to enforce the validity of it for the oplock
 665	 * break handler. The matching put is done at the end of the
 666	 * handler.
 667	 */
 668	cifsFileInfo_get(cfile);
 669
 670	queue_work(cifsoplockd_wq, &cfile->oplock_break);
 671}
 672
 673void cifs_done_oplock_break(struct cifsInodeInfo *cinode)
 674{
 675	clear_bit(CIFS_INODE_PENDING_OPLOCK_BREAK, &cinode->flags);
 676	wake_up_bit(&cinode->flags, CIFS_INODE_PENDING_OPLOCK_BREAK);
 677}
 678
 679bool
 680backup_cred(struct cifs_sb_info *cifs_sb)
 681{
 682	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 683		if (uid_eq(cifs_sb->ctx->backupuid, current_fsuid()))
 684			return true;
 685	}
 686	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 687		if (in_group_p(cifs_sb->ctx->backupgid))
 688			return true;
 689	}
 690
 691	return false;
 692}
 693
 694void
 695cifs_del_pending_open(struct cifs_pending_open *open)
 696{
 697	spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 698	list_del(&open->olist);
 699	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 700}
 701
 702void
 703cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
 704			     struct cifs_pending_open *open)
 705{
 706	memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
 707	open->oplock = CIFS_OPLOCK_NO_CHANGE;
 708	open->tlink = tlink;
 709	fid->pending_open = open;
 710	list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
 711}
 712
 713void
 714cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 715		      struct cifs_pending_open *open)
 716{
 717	spin_lock(&tlink_tcon(tlink)->open_file_lock);
 718	cifs_add_pending_open_locked(fid, tlink, open);
 719	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 720}
 721
 722/*
 723 * Critical section which runs after acquiring deferred_lock.
 724 * As there is no reference count on cifs_deferred_close, pdclose
 725 * should not be used outside deferred_lock.
 726 */
 727bool
 728cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
 729{
 730	struct cifs_deferred_close *dclose;
 731
 732	list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
 733		if ((dclose->netfid == cfile->fid.netfid) &&
 734			(dclose->persistent_fid == cfile->fid.persistent_fid) &&
 735			(dclose->volatile_fid == cfile->fid.volatile_fid)) {
 736			*pdclose = dclose;
 737			return true;
 738		}
 739	}
 740	return false;
 741}
 742
 743/*
 744 * Critical section which runs after acquiring deferred_lock.
 745 */
 746void
 747cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
 748{
 749	bool is_deferred = false;
 750	struct cifs_deferred_close *pdclose;
 751
 752	is_deferred = cifs_is_deferred_close(cfile, &pdclose);
 753	if (is_deferred) {
 754		kfree(dclose);
 755		return;
 756	}
 757
 758	dclose->tlink = cfile->tlink;
 759	dclose->netfid = cfile->fid.netfid;
 760	dclose->persistent_fid = cfile->fid.persistent_fid;
 761	dclose->volatile_fid = cfile->fid.volatile_fid;
 762	list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
 763}
 764
 765/*
 766 * Critical section which runs after acquiring deferred_lock.
 767 */
 768void
 769cifs_del_deferred_close(struct cifsFileInfo *cfile)
 770{
 771	bool is_deferred = false;
 772	struct cifs_deferred_close *dclose;
 773
 774	is_deferred = cifs_is_deferred_close(cfile, &dclose);
 775	if (!is_deferred)
 776		return;
 777	list_del(&dclose->dlist);
 778	kfree(dclose);
 779}
 780
 781void
 782cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
 783{
 784	struct cifsFileInfo *cfile = NULL;
 785	struct file_list *tmp_list, *tmp_next_list;
 786	LIST_HEAD(file_head);
 787
 788	if (cifs_inode == NULL)
 789		return;
 790
 791	spin_lock(&cifs_inode->open_file_lock);
 792	list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
 793		if (delayed_work_pending(&cfile->deferred)) {
 794			if (cancel_delayed_work(&cfile->deferred)) {
 795				spin_lock(&cifs_inode->deferred_lock);
 796				cifs_del_deferred_close(cfile);
 797				spin_unlock(&cifs_inode->deferred_lock);
 798
 799				tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 800				if (tmp_list == NULL)
 801					break;
 802				tmp_list->cfile = cfile;
 803				list_add_tail(&tmp_list->list, &file_head);
 804			}
 805		}
 806	}
 807	spin_unlock(&cifs_inode->open_file_lock);
 808
 809	list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 810		_cifsFileInfo_put(tmp_list->cfile, false, false);
 811		list_del(&tmp_list->list);
 812		kfree(tmp_list);
 813	}
 814}
 815
 816void
 817cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 818{
 819	struct cifsFileInfo *cfile;
 820	struct file_list *tmp_list, *tmp_next_list;
 821	LIST_HEAD(file_head);
 822
 823	spin_lock(&tcon->open_file_lock);
 824	list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 825		if (delayed_work_pending(&cfile->deferred)) {
 826			if (cancel_delayed_work(&cfile->deferred)) {
 827				spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 828				cifs_del_deferred_close(cfile);
 829				spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 830
 831				tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 832				if (tmp_list == NULL)
 833					break;
 834				tmp_list->cfile = cfile;
 835				list_add_tail(&tmp_list->list, &file_head);
 836			}
 837		}
 838	}
 839	spin_unlock(&tcon->open_file_lock);
 840
 841	list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 842		_cifsFileInfo_put(tmp_list->cfile, true, false);
 843		list_del(&tmp_list->list);
 844		kfree(tmp_list);
 845	}
 846}
 847
 848void cifs_close_all_deferred_files_sb(struct cifs_sb_info *cifs_sb)
 849{
 850	struct rb_root *root = &cifs_sb->tlink_tree;
 851	struct rb_node *node;
 852	struct cifs_tcon *tcon;
 853	struct tcon_link *tlink;
 854	struct tcon_list *tmp_list, *q;
 855	LIST_HEAD(tcon_head);
 856
 857	spin_lock(&cifs_sb->tlink_tree_lock);
 858	for (node = rb_first(root); node; node = rb_next(node)) {
 859		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
 860		tcon = tlink_tcon(tlink);
 861		if (IS_ERR(tcon))
 862			continue;
 863		tmp_list = kmalloc(sizeof(struct tcon_list), GFP_ATOMIC);
 864		if (tmp_list == NULL)
 865			break;
 866		tmp_list->tcon = tcon;
 867		/* Take a reference on tcon to prevent it from being freed */
 868		spin_lock(&tcon->tc_lock);
 869		++tcon->tc_count;
 870		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
 871				    netfs_trace_tcon_ref_get_close_defer_files);
 872		spin_unlock(&tcon->tc_lock);
 873		list_add_tail(&tmp_list->entry, &tcon_head);
 874	}
 875	spin_unlock(&cifs_sb->tlink_tree_lock);
 876
 877	list_for_each_entry_safe(tmp_list, q, &tcon_head, entry) {
 878		cifs_close_all_deferred_files(tmp_list->tcon);
 879		list_del(&tmp_list->entry);
 880		cifs_put_tcon(tmp_list->tcon, netfs_trace_tcon_ref_put_close_defer_files);
 881		kfree(tmp_list);
 882	}
 883}
 884
 885void cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon,
 886					   struct dentry *dentry)
 887{
 888	struct file_list *tmp_list, *tmp_next_list;
 889	struct cifsFileInfo *cfile;
 890	LIST_HEAD(file_head);
 891
 892	spin_lock(&tcon->open_file_lock);
 893	list_for_each_entry(cfile, &tcon->openFileList, tlist) {
 894		if ((cfile->dentry == dentry) &&
 895		    delayed_work_pending(&cfile->deferred) &&
 896		    cancel_delayed_work(&cfile->deferred)) {
 897			spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 898			cifs_del_deferred_close(cfile);
 899			spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
 900
 901			tmp_list = kmalloc(sizeof(struct file_list), GFP_ATOMIC);
 902			if (tmp_list == NULL)
 903				break;
 904			tmp_list->cfile = cfile;
 905			list_add_tail(&tmp_list->list, &file_head);
 906		}
 907	}
 908	spin_unlock(&tcon->open_file_lock);
 909
 910	list_for_each_entry_safe(tmp_list, tmp_next_list, &file_head, list) {
 911		_cifsFileInfo_put(tmp_list->cfile, true, false);
 912		list_del(&tmp_list->list);
 913		kfree(tmp_list);
 914	}
 915}
 916
 917/*
 918 * If a dentry has been deleted, all corresponding open handles should know that
 919 * so that we do not defer close them.
 920 */
 921void cifs_mark_open_handles_for_deleted_file(struct inode *inode,
 922					     const char *path)
 923{
 924	struct cifsFileInfo *cfile;
 925	void *page;
 926	const char *full_path;
 927	struct cifsInodeInfo *cinode = CIFS_I(inode);
 928
 929	page = alloc_dentry_path();
 930	spin_lock(&cinode->open_file_lock);
 931
 932	/*
 933	 * note: we need to construct path from dentry and compare only if the
 934	 * inode has any hardlinks. When number of hardlinks is 1, we can just
 935	 * mark all open handles since they are going to be from the same file.
 936	 */
 937	if (inode->i_nlink > 1) {
 938		list_for_each_entry(cfile, &cinode->openFileList, flist) {
 939			full_path = build_path_from_dentry(cfile->dentry, page);
 940			if (!IS_ERR(full_path) && strcmp(full_path, path) == 0)
 941				cfile->status_file_deleted = true;
 942		}
 943	} else {
 944		list_for_each_entry(cfile, &cinode->openFileList, flist)
 945			cfile->status_file_deleted = true;
 946	}
 947	spin_unlock(&cinode->open_file_lock);
 948	free_dentry_path(page);
 949}
 950
 951/* parses DFS referral V3 structure
 952 * caller is responsible for freeing target_nodes
 953 * returns:
 954 * - on success - 0
 955 * - on failure - errno
 956 */
 957int
 958parse_dfs_referrals(struct get_dfs_referral_rsp *rsp, u32 rsp_size,
 959		    unsigned int *num_of_nodes,
 960		    struct dfs_info3_param **target_nodes,
 961		    const struct nls_table *nls_codepage, int remap,
 962		    const char *searchName, bool is_unicode)
 963{
 964	int i, rc = 0;
 965	char *data_end;
 966	struct dfs_referral_level_3 *ref;
 967
 968	if (rsp_size < sizeof(*rsp)) {
 969		cifs_dbg(VFS | ONCE,
 970			 "%s: header is malformed (size is %u, must be %zu)\n",
 971			 __func__, rsp_size, sizeof(*rsp));
 972		rc = -EINVAL;
 973		goto parse_DFS_referrals_exit;
 974	}
 975
 976	*num_of_nodes = le16_to_cpu(rsp->NumberOfReferrals);
 977
 978	if (*num_of_nodes < 1) {
 979		cifs_dbg(VFS | ONCE, "%s: [path=%s] num_referrals must be at least > 0, but we got %d\n",
 980			 __func__, searchName, *num_of_nodes);
 981		rc = -ENOENT;
 982		goto parse_DFS_referrals_exit;
 983	}
 984
 985	if (sizeof(*rsp) + *num_of_nodes * sizeof(REFERRAL3) > rsp_size) {
 986		cifs_dbg(VFS | ONCE,
 987			 "%s: malformed buffer (size is %u, must be at least %zu)\n",
 988			 __func__, rsp_size,
 989			 sizeof(*rsp) + *num_of_nodes * sizeof(REFERRAL3));
 990		rc = -EINVAL;
 991		goto parse_DFS_referrals_exit;
 992	}
 993
 994	ref = (struct dfs_referral_level_3 *) &(rsp->referrals);
 995	if (ref->VersionNumber != cpu_to_le16(3)) {
 996		cifs_dbg(VFS, "Referrals of V%d version are not supported, should be V3\n",
 997			 le16_to_cpu(ref->VersionNumber));
 998		rc = -EINVAL;
 999		goto parse_DFS_referrals_exit;
1000	}
1001
1002	/* get the upper boundary of the resp buffer */
1003	data_end = (char *)rsp + rsp_size;
1004
1005	cifs_dbg(FYI, "num_referrals: %d dfs flags: 0x%x ...\n",
1006		 *num_of_nodes, le32_to_cpu(rsp->DFSFlags));
1007
1008	*target_nodes = kcalloc(*num_of_nodes, sizeof(struct dfs_info3_param),
1009				GFP_KERNEL);
1010	if (*target_nodes == NULL) {
1011		rc = -ENOMEM;
1012		goto parse_DFS_referrals_exit;
1013	}
1014
1015	/* collect necessary data from referrals */
1016	for (i = 0; i < *num_of_nodes; i++) {
1017		char *temp;
1018		int max_len;
1019		struct dfs_info3_param *node = (*target_nodes)+i;
1020
1021		node->flags = le32_to_cpu(rsp->DFSFlags);
1022		if (is_unicode) {
1023			__le16 *tmp = kmalloc(strlen(searchName)*2 + 2,
1024						GFP_KERNEL);
1025			if (tmp == NULL) {
1026				rc = -ENOMEM;
1027				goto parse_DFS_referrals_exit;
1028			}
1029			cifsConvertToUTF16((__le16 *) tmp, searchName,
1030					   PATH_MAX, nls_codepage, remap);
1031			node->path_consumed = cifs_utf16_bytes(tmp,
1032					le16_to_cpu(rsp->PathConsumed),
1033					nls_codepage);
1034			kfree(tmp);
1035		} else
1036			node->path_consumed = le16_to_cpu(rsp->PathConsumed);
1037
1038		node->server_type = le16_to_cpu(ref->ServerType);
1039		node->ref_flag = le16_to_cpu(ref->ReferralEntryFlags);
1040
1041		/* copy DfsPath */
1042		temp = (char *)ref + le16_to_cpu(ref->DfsPathOffset);
1043		max_len = data_end - temp;
1044		node->path_name = cifs_strndup_from_utf16(temp, max_len,
1045						is_unicode, nls_codepage);
1046		if (!node->path_name) {
1047			rc = -ENOMEM;
1048			goto parse_DFS_referrals_exit;
1049		}
1050
1051		/* copy link target UNC */
1052		temp = (char *)ref + le16_to_cpu(ref->NetworkAddressOffset);
1053		max_len = data_end - temp;
1054		node->node_name = cifs_strndup_from_utf16(temp, max_len,
1055						is_unicode, nls_codepage);
1056		if (!node->node_name) {
1057			rc = -ENOMEM;
1058			goto parse_DFS_referrals_exit;
1059		}
1060
1061		node->ttl = le32_to_cpu(ref->TimeToLive);
1062
1063		ref++;
1064	}
1065
1066parse_DFS_referrals_exit:
1067	if (rc) {
1068		free_dfs_info_array(*target_nodes, *num_of_nodes);
1069		*target_nodes = NULL;
1070		*num_of_nodes = 0;
1071	}
1072	return rc;
1073}
1074
1075/**
1076 * cifs_alloc_hash - allocate hash and hash context together
1077 * @name: The name of the crypto hash algo
1078 * @sdesc: SHASH descriptor where to put the pointer to the hash TFM
1079 *
1080 * The caller has to make sure @sdesc is initialized to either NULL or
1081 * a valid context. It can be freed via cifs_free_hash().
1082 */
1083int
1084cifs_alloc_hash(const char *name, struct shash_desc **sdesc)
1085{
1086	int rc = 0;
1087	struct crypto_shash *alg = NULL;
1088
1089	if (*sdesc)
1090		return 0;
1091
1092	alg = crypto_alloc_shash(name, 0, 0);
1093	if (IS_ERR(alg)) {
1094		cifs_dbg(VFS, "Could not allocate shash TFM '%s'\n", name);
1095		rc = PTR_ERR(alg);
1096		*sdesc = NULL;
1097		return rc;
1098	}
1099
1100	*sdesc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(alg), GFP_KERNEL);
1101	if (*sdesc == NULL) {
1102		cifs_dbg(VFS, "no memory left to allocate shash TFM '%s'\n", name);
1103		crypto_free_shash(alg);
1104		return -ENOMEM;
1105	}
1106
1107	(*sdesc)->tfm = alg;
1108	return 0;
1109}
1110
1111/**
1112 * cifs_free_hash - free hash and hash context together
1113 * @sdesc: Where to find the pointer to the hash TFM
1114 *
1115 * Freeing a NULL descriptor is safe.
1116 */
1117void
1118cifs_free_hash(struct shash_desc **sdesc)
1119{
1120	if (unlikely(!sdesc) || !*sdesc)
1121		return;
1122
1123	if ((*sdesc)->tfm) {
1124		crypto_free_shash((*sdesc)->tfm);
1125		(*sdesc)->tfm = NULL;
1126	}
1127
1128	kfree_sensitive(*sdesc);
1129	*sdesc = NULL;
1130}
1131
1132void extract_unc_hostname(const char *unc, const char **h, size_t *len)
1133{
1134	const char *end;
1135
1136	/* skip initial slashes */
1137	while (*unc && (*unc == '\\' || *unc == '/'))
1138		unc++;
1139
1140	end = unc;
1141
1142	while (*end && !(*end == '\\' || *end == '/'))
1143		end++;
1144
1145	*h = unc;
1146	*len = end - unc;
1147}
1148
1149/**
1150 * copy_path_name - copy src path to dst, possibly truncating
1151 * @dst: The destination buffer
1152 * @src: The source name
1153 *
1154 * returns number of bytes written (including trailing nul)
1155 */
1156int copy_path_name(char *dst, const char *src)
1157{
1158	int name_len;
1159
1160	/*
1161	 * PATH_MAX includes nul, so if strlen(src) >= PATH_MAX it
1162	 * will truncate and strlen(dst) will be PATH_MAX-1
1163	 */
1164	name_len = strscpy(dst, src, PATH_MAX);
1165	if (WARN_ON_ONCE(name_len < 0))
1166		name_len = PATH_MAX-1;
1167
1168	/* we count the trailing nul */
1169	name_len++;
1170	return name_len;
1171}
1172
1173struct super_cb_data {
1174	void *data;
1175	struct super_block *sb;
1176};
1177
1178static void tcon_super_cb(struct super_block *sb, void *arg)
1179{
1180	struct super_cb_data *sd = arg;
1181	struct cifs_sb_info *cifs_sb;
1182	struct cifs_tcon *t1 = sd->data, *t2;
1183
1184	if (sd->sb)
1185		return;
1186
1187	cifs_sb = CIFS_SB(sb);
1188	t2 = cifs_sb_master_tcon(cifs_sb);
1189
1190	spin_lock(&t2->tc_lock);
1191	if ((t1->ses == t2->ses ||
1192	     t1->ses->dfs_root_ses == t2->ses->dfs_root_ses) &&
1193	    t1->ses->server == t2->ses->server &&
1194	    t2->origin_fullpath &&
1195	    dfs_src_pathname_equal(t2->origin_fullpath, t1->origin_fullpath))
1196		sd->sb = sb;
1197	spin_unlock(&t2->tc_lock);
1198}
1199
1200static struct super_block *__cifs_get_super(void (*f)(struct super_block *, void *),
1201					    void *data)
1202{
1203	struct super_cb_data sd = {
1204		.data = data,
1205		.sb = NULL,
1206	};
1207	struct file_system_type **fs_type = (struct file_system_type *[]) {
1208		&cifs_fs_type, &smb3_fs_type, NULL,
1209	};
1210
1211	for (; *fs_type; fs_type++) {
1212		iterate_supers_type(*fs_type, f, &sd);
1213		if (sd.sb) {
1214			/*
1215			 * Grab an active reference in order to prevent automounts (DFS links)
1216			 * of expiring and then freeing up our cifs superblock pointer while
1217			 * we're doing failover.
1218			 */
1219			cifs_sb_active(sd.sb);
1220			return sd.sb;
1221		}
1222	}
1223	pr_warn_once("%s: could not find dfs superblock\n", __func__);
1224	return ERR_PTR(-EINVAL);
1225}
1226
1227static void __cifs_put_super(struct super_block *sb)
1228{
1229	if (!IS_ERR_OR_NULL(sb))
1230		cifs_sb_deactive(sb);
1231}
1232
1233struct super_block *cifs_get_dfs_tcon_super(struct cifs_tcon *tcon)
1234{
1235	spin_lock(&tcon->tc_lock);
1236	if (!tcon->origin_fullpath) {
1237		spin_unlock(&tcon->tc_lock);
1238		return ERR_PTR(-ENOENT);
1239	}
1240	spin_unlock(&tcon->tc_lock);
1241	return __cifs_get_super(tcon_super_cb, tcon);
1242}
1243
1244void cifs_put_tcp_super(struct super_block *sb)
1245{
1246	__cifs_put_super(sb);
1247}
1248
1249#ifdef CONFIG_CIFS_DFS_UPCALL
1250int match_target_ip(struct TCP_Server_Info *server,
1251		    const char *host, size_t hostlen,
1252		    bool *result)
1253{
1254	struct sockaddr_storage ss;
1255	int rc;
1256
1257	cifs_dbg(FYI, "%s: hostname=%.*s\n", __func__, (int)hostlen, host);
1258
1259	*result = false;
1260
1261	rc = dns_resolve_name(server->dns_dom, host, hostlen,
1262			      (struct sockaddr *)&ss);
1263	if (rc < 0)
1264		return rc;
1265
1266	spin_lock(&server->srv_lock);
1267	*result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
1268	spin_unlock(&server->srv_lock);
1269	cifs_dbg(FYI, "%s: ip addresses matched: %s\n", __func__, str_yes_no(*result));
1270	return 0;
1271}
1272
1273int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
1274{
1275	int rc;
1276
1277	kfree(cifs_sb->prepath);
1278	cifs_sb->prepath = NULL;
1279
1280	if (prefix && *prefix) {
1281		cifs_sb->prepath = cifs_sanitize_prepath(prefix, GFP_ATOMIC);
1282		if (IS_ERR(cifs_sb->prepath)) {
1283			rc = PTR_ERR(cifs_sb->prepath);
1284			cifs_sb->prepath = NULL;
1285			return rc;
1286		}
1287		if (cifs_sb->prepath)
1288			convert_delimiter(cifs_sb->prepath, CIFS_DIR_SEP(cifs_sb));
1289	}
1290
1291	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
1292	return 0;
1293}
1294
1295/*
1296 * Handle weird Windows SMB server behaviour. It responds with
1297 * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request for
1298 * "\<server>\<dfsname>\<linkpath>" DFS reference, where <dfsname> contains
1299 * non-ASCII unicode symbols.
1300 */
1301int cifs_inval_name_dfs_link_error(const unsigned int xid,
1302				   struct cifs_tcon *tcon,
1303				   struct cifs_sb_info *cifs_sb,
1304				   const char *full_path,
1305				   bool *islink)
1306{
1307	struct TCP_Server_Info *server = tcon->ses->server;
1308	struct cifs_ses *ses = tcon->ses;
1309	size_t len;
1310	char *path;
1311	char *ref_path;
1312
1313	*islink = false;
1314
1315	/*
1316	 * Fast path - skip check when @full_path doesn't have a prefix path to
1317	 * look up or tcon is not DFS.
1318	 */
1319	if (strlen(full_path) < 2 || !cifs_sb ||
1320	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) ||
1321	    !is_tcon_dfs(tcon))
1322		return 0;
1323
1324	spin_lock(&server->srv_lock);
1325	if (!server->leaf_fullpath) {
1326		spin_unlock(&server->srv_lock);
1327		return 0;
1328	}
1329	spin_unlock(&server->srv_lock);
1330
1331	/*
1332	 * Slow path - tcon is DFS and @full_path has prefix path, so attempt
1333	 * to get a referral to figure out whether it is an DFS link.
1334	 */
1335	len = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1) + strlen(full_path) + 1;
1336	path = kmalloc(len, GFP_KERNEL);
1337	if (!path)
1338		return -ENOMEM;
1339
1340	scnprintf(path, len, "%s%s", tcon->tree_name, full_path);
1341	ref_path = dfs_cache_canonical_path(path + 1, cifs_sb->local_nls,
1342					    cifs_remap(cifs_sb));
1343	kfree(path);
1344
1345	if (IS_ERR(ref_path)) {
1346		if (PTR_ERR(ref_path) != -EINVAL)
1347			return PTR_ERR(ref_path);
1348	} else {
1349		struct dfs_info3_param *refs = NULL;
1350		int num_refs = 0;
1351
1352		/*
1353		 * XXX: we are not using dfs_cache_find() here because we might
1354		 * end up filling all the DFS cache and thus potentially
1355		 * removing cached DFS targets that the client would eventually
1356		 * need during failover.
1357		 */
1358		ses = CIFS_DFS_ROOT_SES(ses);
1359		if (ses->server->ops->get_dfs_refer &&
1360		    !ses->server->ops->get_dfs_refer(xid, ses, ref_path, &refs,
1361						     &num_refs, cifs_sb->local_nls,
1362						     cifs_remap(cifs_sb)))
1363			*islink = refs[0].server_type == DFS_TYPE_LINK;
1364		free_dfs_info_array(refs, num_refs);
1365		kfree(ref_path);
1366	}
1367	return 0;
1368}
1369#endif
1370
1371int cifs_wait_for_server_reconnect(struct TCP_Server_Info *server, bool retry)
1372{
1373	int timeout = 10;
1374	int rc;
1375
1376	spin_lock(&server->srv_lock);
1377	if (server->tcpStatus != CifsNeedReconnect) {
1378		spin_unlock(&server->srv_lock);
1379		return 0;
1380	}
1381	timeout *= server->nr_targets;
1382	spin_unlock(&server->srv_lock);
1383
1384	/*
1385	 * Give demultiplex thread up to 10 seconds to each target available for
1386	 * reconnect -- should be greater than cifs socket timeout which is 7
1387	 * seconds.
1388	 *
1389	 * On "soft" mounts we wait once. Hard mounts keep retrying until
1390	 * process is killed or server comes back on-line.
1391	 */
1392	do {
1393		rc = wait_event_interruptible_timeout(server->response_q,
1394						      (server->tcpStatus != CifsNeedReconnect),
1395						      timeout * HZ);
1396		if (rc < 0) {
1397			cifs_dbg(FYI, "%s: aborting reconnect due to received signal\n",
1398				 __func__);
1399			return -ERESTARTSYS;
1400		}
1401
1402		/* are we still trying to reconnect? */
1403		spin_lock(&server->srv_lock);
1404		if (server->tcpStatus != CifsNeedReconnect) {
1405			spin_unlock(&server->srv_lock);
1406			return 0;
1407		}
1408		spin_unlock(&server->srv_lock);
1409	} while (retry);
1410
1411	cifs_dbg(FYI, "%s: gave up waiting on reconnect\n", __func__);
1412	return -EHOSTDOWN;
1413}