smb2ops.c

/*
 *  SMB2 version specific operations
 *
 *  Copyright (c) 2012, Jeff Layton <jlayton@redhat.com>
 *
 *  This library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License v2 as published
 *  by the Free Software Foundation.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *  the GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/pagemap.h>
#include <linux/vfs.h>
#include "cifsglob.h"
#include "smb2pdu.h"
#include "smb2proto.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
#include "smb2status.h"
#include "smb2glob.h"

static int
change_conf(struct TCP_Server_Info *server)
{
	server->credits += server->echo_credits + server->oplock_credits;
	server->oplock_credits = server->echo_credits = 0;
	switch (server->credits) {
	case 0:
		return -1;
	case 1:
		server->echoes = false;
		server->oplocks = false;
		cifs_dbg(VFS, "disabling echoes and oplocks\n");
		break;
	case 2:
		server->echoes = true;
		server->oplocks = false;
		server->echo_credits = 1;
		cifs_dbg(FYI, "disabling oplocks\n");
		break;
	default:
		server->echoes = true;
		server->oplocks = true;
		server->echo_credits = 1;
		server->oplock_credits = 1;
	}
	server->credits -= server->echo_credits + server->oplock_credits;
	return 0;
}

static void
smb2_add_credits(struct TCP_Server_Info *server, const unsigned int add,
		 const int optype)
{
	int *val, rc = 0;
	spin_lock(&server->req_lock);
	val = server->ops->get_credits_field(server, optype);
	*val += add;
	server->in_flight--;
	if (server->in_flight == 0 && (optype & CIFS_OP_MASK) != CIFS_NEG_OP)
		rc = change_conf(server);
	/*
	 * Sometimes server returns 0 credits on oplock break ack - we need to
	 * rebalance credits in this case.
	 */
	else if (server->in_flight > 0 && server->oplock_credits == 0 &&
		 server->oplocks) {
		if (server->credits > 1) {
			server->credits--;
			server->oplock_credits++;
		}
	}
	spin_unlock(&server->req_lock);
	wake_up(&server->request_q);
	if (rc)
		cifs_reconnect(server);
}

static void
smb2_set_credits(struct TCP_Server_Info *server, const int val)
{
	spin_lock(&server->req_lock);
	server->credits = val;
	spin_unlock(&server->req_lock);
}

static int *
smb2_get_credits_field(struct TCP_Server_Info *server, const int optype)
{
	switch (optype) {
	case CIFS_ECHO_OP:
		return &server->echo_credits;
	case CIFS_OBREAK_OP:
		return &server->oplock_credits;
	default:
		return &server->credits;
	}
}

static unsigned int
smb2_get_credits(struct mid_q_entry *mid)
{
	return le16_to_cpu(((struct smb2_hdr *)mid->resp_buf)->CreditRequest);
}

static __u64
smb2_get_next_mid(struct TCP_Server_Info *server)
{
	__u64 mid;
	/* for SMB2 we need the current value */
	spin_lock(&GlobalMid_Lock);
	mid = server->CurrentMid++;
	spin_unlock(&GlobalMid_Lock);
	return mid;
}

static struct mid_q_entry *
smb2_find_mid(struct TCP_Server_Info *server, char *buf)
{
	struct mid_q_entry *mid;
	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;

	spin_lock(&GlobalMid_Lock);
	list_for_each_entry(mid, &server->pending_mid_q, qhead) {
		if ((mid->mid == hdr->MessageId) &&
		    (mid->mid_state == MID_REQUEST_SUBMITTED) &&
		    (mid->command == hdr->Command)) {
			spin_unlock(&GlobalMid_Lock);
			return mid;
		}
	}
	spin_unlock(&GlobalMid_Lock);
	return NULL;
}

static void
smb2_dump_detail(void *buf)
{
#ifdef CONFIG_CIFS_DEBUG2
	struct smb2_hdr *smb = (struct smb2_hdr *)buf;

	cifs_dbg(VFS, "Cmd: %d Err: 0x%x Flags: 0x%x Mid: %llu Pid: %d\n",
		 smb->Command, smb->Status, smb->Flags, smb->MessageId,
		 smb->ProcessId);
	cifs_dbg(VFS, "smb buf %p len %u\n", smb, smb2_calc_size(smb));
#endif
}

static bool
smb2_need_neg(struct TCP_Server_Info *server)
{
	return server->max_read == 0;
}

static int
smb2_negotiate(const unsigned int xid, struct cifs_ses *ses)
{
	int rc;
	ses->server->CurrentMid = 0;
	rc = SMB2_negotiate(xid, ses);
	/* BB we probably don't need to retry with modern servers */
	if (rc == -EAGAIN)
		rc = -EHOSTDOWN;
	return rc;
}

static unsigned int
smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
{
	struct TCP_Server_Info *server = tcon->ses->server;
	unsigned int wsize;

	/* start with specified wsize, or default */
	wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE;
	wsize = min_t(unsigned int, wsize, server->max_write);
	/*
	 * limit write size to 2 ** 16, because we don't support multicredit
	 * requests now.
	 */
	wsize = min_t(unsigned int, wsize, 2 << 15);

	return wsize;
}

static unsigned int
smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
{
	struct TCP_Server_Info *server = tcon->ses->server;
	unsigned int rsize;

	/* start with specified rsize, or default */
	rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE;
	rsize = min_t(unsigned int, rsize, server->max_read);
	/*
	 * limit write size to 2 ** 16, because we don't support multicredit
	 * requests now.
	 */
	rsize = min_t(unsigned int, rsize, 2 << 15);

	return rsize;
}

static void
smb2_qfs_tcon(const unsigned int xid, struct cifs_tcon *tcon)
{
	int rc;
	__le16 srch_path = 0; /* Null - open root of share */
	u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
	struct cifs_open_parms oparms;
	struct cifs_fid fid;

	oparms.tcon = tcon;
	oparms.desired_access = FILE_READ_ATTRIBUTES;
	oparms.disposition = FILE_OPEN;
	oparms.create_options = 0;
	oparms.fid = &fid;
	oparms.reconnect = false;

	rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL);
	if (rc)
		return;

	SMB2_QFS_attr(xid, tcon, fid.persistent_fid, fid.volatile_fid,
			FS_ATTRIBUTE_INFORMATION);
	SMB2_QFS_attr(xid, tcon, fid.persistent_fid, fid.volatile_fid,
			FS_DEVICE_INFORMATION);
	SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
	return;
}

static int
smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
			struct cifs_sb_info *cifs_sb, const char *full_path)
{
	int rc;
	__le16 *utf16_path;
	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
	struct cifs_open_parms oparms;
	struct cifs_fid fid;

	utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
	if (!utf16_path)
		return -ENOMEM;

	oparms.tcon = tcon;
	oparms.desired_access = FILE_READ_ATTRIBUTES;
	oparms.disposition = FILE_OPEN;
	oparms.create_options = 0;
	oparms.fid = &fid;
	oparms.reconnect = false;

	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
	if (rc) {
		kfree(utf16_path);
		return rc;
	}

	rc = SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
	kfree(utf16_path);
	return rc;
}

static int
smb2_get_srv_inum(const unsigned int xid, struct cifs_tcon *tcon,
		  struct cifs_sb_info *cifs_sb, const char *full_path,
		  u64 *uniqueid, FILE_ALL_INFO *data)
{
	*uniqueid = le64_to_cpu(data->IndexNumber);
	return 0;
}

static int
smb2_query_file_info(const unsigned int xid, struct cifs_tcon *tcon,
		     struct cifs_fid *fid, FILE_ALL_INFO *data)
{
	int rc;
	struct smb2_file_all_info *smb2_data;

	smb2_data = kzalloc(sizeof(struct smb2_file_all_info) + MAX_NAME * 2,
			    GFP_KERNEL);
	if (smb2_data == NULL)
		return -ENOMEM;

	rc = SMB2_query_info(xid, tcon, fid->persistent_fid, fid->volatile_fid,
			     smb2_data);
	if (!rc)
		move_smb2_info_to_cifs(data, smb2_data);
	kfree(smb2_data);
	return rc;
}

static bool
smb2_can_echo(struct TCP_Server_Info *server)
{
	return server->echoes;
}

static void
smb2_clear_stats(struct cifs_tcon *tcon)
{
#ifdef CONFIG_CIFS_STATS
	int i;
	for (i = 0; i < NUMBER_OF_SMB2_COMMANDS; i++) {
		atomic_set(&tcon->stats.smb2_stats.smb2_com_sent[i], 0);
		atomic_set(&tcon->stats.smb2_stats.smb2_com_failed[i], 0);
	}
#endif
}

static void
smb2_dump_share_caps(struct seq_file *m, struct cifs_tcon *tcon)
{
	seq_puts(m, "\n\tShare Capabilities:");
	if (tcon->capabilities & SMB2_SHARE_CAP_DFS)
		seq_puts(m, " DFS,");
	if (tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
		seq_puts(m, " CONTINUOUS AVAILABILITY,");
	if (tcon->capabilities & SMB2_SHARE_CAP_SCALEOUT)
		seq_puts(m, " SCALEOUT,");
	if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER)
		seq_puts(m, " CLUSTER,");
	if (tcon->capabilities & SMB2_SHARE_CAP_ASYMMETRIC)
		seq_puts(m, " ASYMMETRIC,");
	if (tcon->capabilities == 0)
		seq_puts(m, " None");
	seq_printf(m, "\tShare Flags: 0x%x", tcon->share_flags);
}

static void
smb2_print_stats(struct seq_file *m, struct cifs_tcon *tcon)
{
#ifdef CONFIG_CIFS_STATS
	atomic_t *sent = tcon->stats.smb2_stats.smb2_com_sent;
	atomic_t *failed = tcon->stats.smb2_stats.smb2_com_failed;
	seq_printf(m, "\nNegotiates: %d sent %d failed",
		   atomic_read(&sent[SMB2_NEGOTIATE_HE]),
		   atomic_read(&failed[SMB2_NEGOTIATE_HE]));
	seq_printf(m, "\nSessionSetups: %d sent %d failed",
		   atomic_read(&sent[SMB2_SESSION_SETUP_HE]),
		   atomic_read(&failed[SMB2_SESSION_SETUP_HE]));
	seq_printf(m, "\nLogoffs: %d sent %d failed",
		   atomic_read(&sent[SMB2_LOGOFF_HE]),
		   atomic_read(&failed[SMB2_LOGOFF_HE]));
	seq_printf(m, "\nTreeConnects: %d sent %d failed",
		   atomic_read(&sent[SMB2_TREE_CONNECT_HE]),
		   atomic_read(&failed[SMB2_TREE_CONNECT_HE]));
	seq_printf(m, "\nTreeDisconnects: %d sent %d failed",
		   atomic_read(&sent[SMB2_TREE_DISCONNECT_HE]),
		   atomic_read(&failed[SMB2_TREE_DISCONNECT_HE]));
	seq_printf(m, "\nCreates: %d sent %d failed",
		   atomic_read(&sent[SMB2_CREATE_HE]),
		   atomic_read(&failed[SMB2_CREATE_HE]));
	seq_printf(m, "\nCloses: %d sent %d failed",
		   atomic_read(&sent[SMB2_CLOSE_HE]),
		   atomic_read(&failed[SMB2_CLOSE_HE]));
	seq_printf(m, "\nFlushes: %d sent %d failed",
		   atomic_read(&sent[SMB2_FLUSH_HE]),
		   atomic_read(&failed[SMB2_FLUSH_HE]));
	seq_printf(m, "\nReads: %d sent %d failed",
		   atomic_read(&sent[SMB2_READ_HE]),
		   atomic_read(&failed[SMB2_READ_HE]));
	seq_printf(m, "\nWrites: %d sent %d failed",
		   atomic_read(&sent[SMB2_WRITE_HE]),
		   atomic_read(&failed[SMB2_WRITE_HE]));
	seq_printf(m, "\nLocks: %d sent %d failed",
		   atomic_read(&sent[SMB2_LOCK_HE]),
		   atomic_read(&failed[SMB2_LOCK_HE]));
	seq_printf(m, "\nIOCTLs: %d sent %d failed",
		   atomic_read(&sent[SMB2_IOCTL_HE]),
		   atomic_read(&failed[SMB2_IOCTL_HE]));
	seq_printf(m, "\nCancels: %d sent %d failed",
		   atomic_read(&sent[SMB2_CANCEL_HE]),
		   atomic_read(&failed[SMB2_CANCEL_HE]));
	seq_printf(m, "\nEchos: %d sent %d failed",
		   atomic_read(&sent[SMB2_ECHO_HE]),
		   atomic_read(&failed[SMB2_ECHO_HE]));
	seq_printf(m, "\nQueryDirectories: %d sent %d failed",
		   atomic_read(&sent[SMB2_QUERY_DIRECTORY_HE]),
		   atomic_read(&failed[SMB2_QUERY_DIRECTORY_HE]));
	seq_printf(m, "\nChangeNotifies: %d sent %d failed",
		   atomic_read(&sent[SMB2_CHANGE_NOTIFY_HE]),
		   atomic_read(&failed[SMB2_CHANGE_NOTIFY_HE]));
	seq_printf(m, "\nQueryInfos: %d sent %d failed",
		   atomic_read(&sent[SMB2_QUERY_INFO_HE]),
		   atomic_read(&failed[SMB2_QUERY_INFO_HE]));
	seq_printf(m, "\nSetInfos: %d sent %d failed",
		   atomic_read(&sent[SMB2_SET_INFO_HE]),
		   atomic_read(&failed[SMB2_SET_INFO_HE]));
	seq_printf(m, "\nOplockBreaks: %d sent %d failed",
		   atomic_read(&sent[SMB2_OPLOCK_BREAK_HE]),
		   atomic_read(&failed[SMB2_OPLOCK_BREAK_HE]));
#endif
}

static void
smb2_set_fid(struct cifsFileInfo *cfile, struct cifs_fid *fid, __u32 oplock)
{
	struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
	struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;

	cfile->fid.persistent_fid = fid->persistent_fid;
	cfile->fid.volatile_fid = fid->volatile_fid;
	server->ops->set_oplock_level(cinode, oplock, fid->epoch,
				      &fid->purge_cache);
	cinode->can_cache_brlcks = CIFS_CACHE_WRITE(cinode);
}

static void
smb2_close_file(const unsigned int xid, struct cifs_tcon *tcon,
		struct cifs_fid *fid)
{
	SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

static int
smb2_flush_file(const unsigned int xid, struct cifs_tcon *tcon,
		struct cifs_fid *fid)
{
	return SMB2_flush(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

static unsigned int
smb2_read_data_offset(char *buf)
{
	struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;
	return rsp->DataOffset;
}

static unsigned int
smb2_read_data_length(char *buf)
{
	struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;
	return le32_to_cpu(rsp->DataLength);
}


static int
smb2_sync_read(const unsigned int xid, struct cifsFileInfo *cfile,
	       struct cifs_io_parms *parms, unsigned int *bytes_read,
	       char **buf, int *buf_type)
{
	parms->persistent_fid = cfile->fid.persistent_fid;
	parms->volatile_fid = cfile->fid.volatile_fid;
	return SMB2_read(xid, parms, bytes_read, buf, buf_type);
}

static int
smb2_sync_write(const unsigned int xid, struct cifsFileInfo *cfile,
		struct cifs_io_parms *parms, unsigned int *written,
		struct kvec *iov, unsigned long nr_segs)
{

	parms->persistent_fid = cfile->fid.persistent_fid;
	parms->volatile_fid = cfile->fid.volatile_fid;
	return SMB2_write(xid, parms, written, iov, nr_segs);
}

static int
smb2_set_file_size(const unsigned int xid, struct cifs_tcon *tcon,
		   struct cifsFileInfo *cfile, __u64 size, bool set_alloc)
{
	__le64 eof = cpu_to_le64(size);
	return SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
			    cfile->fid.volatile_fid, cfile->pid, &eof);
}

static int
smb2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
		   struct cifsFileInfo *cfile)
{
	return SMB2_set_compression(xid, tcon, cfile->fid.persistent_fid,
			    cfile->fid.volatile_fid);
}

static int
smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
		     const char *path, struct cifs_sb_info *cifs_sb,
		     struct cifs_fid *fid, __u16 search_flags,
		     struct cifs_search_info *srch_inf)
{
	__le16 *utf16_path;
	int rc;
	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
	struct cifs_open_parms oparms;

	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
	if (!utf16_path)
		return -ENOMEM;

	oparms.tcon = tcon;
	oparms.desired_access = FILE_READ_ATTRIBUTES | FILE_READ_DATA;
	oparms.disposition = FILE_OPEN;
	oparms.create_options = 0;
	oparms.fid = fid;
	oparms.reconnect = false;

	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL);
	kfree(utf16_path);
	if (rc) {
		cifs_dbg(VFS, "open dir failed\n");
		return rc;
	}

	srch_inf->entries_in_buffer = 0;
	srch_inf->index_of_last_entry = 0;

	rc = SMB2_query_directory(xid, tcon, fid->persistent_fid,
				  fid->volatile_fid, 0, srch_inf);
	if (rc) {
		cifs_dbg(VFS, "query directory failed\n");
		SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
	}
	return rc;
}

static int
smb2_query_dir_next(const unsigned int xid, struct cifs_tcon *tcon,
		    struct cifs_fid *fid, __u16 search_flags,
		    struct cifs_search_info *srch_inf)
{
	return SMB2_query_directory(xid, tcon, fid->persistent_fid,
				    fid->volatile_fid, 0, srch_inf);
}

static int
smb2_close_dir(const unsigned int xid, struct cifs_tcon *tcon,
	       struct cifs_fid *fid)
{
	return SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
}

/*
* If we negotiate SMB2 protocol and get STATUS_PENDING - update
* the number of credits and return true. Otherwise - return false.
*/
static bool
smb2_is_status_pending(char *buf, struct TCP_Server_Info *server, int length)
{
	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;

	if (hdr->Status != STATUS_PENDING)
		return false;

	if (!length) {
		spin_lock(&server->req_lock);
		server->credits += le16_to_cpu(hdr->CreditRequest);
		spin_unlock(&server->req_lock);
		wake_up(&server->request_q);
	}

	return true;
}

static int
smb2_oplock_response(struct cifs_tcon *tcon, struct cifs_fid *fid,
		     struct cifsInodeInfo *cinode)
{
	if (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LEASING)
		return SMB2_lease_break(0, tcon, cinode->lease_key,
					smb2_get_lease_state(cinode));

	return SMB2_oplock_break(0, tcon, fid->persistent_fid,
				 fid->volatile_fid,
				 CIFS_CACHE_READ(cinode) ? 1 : 0);
}

static int
smb2_queryfs(const unsigned int xid, struct cifs_tcon *tcon,
	     struct kstatfs *buf)
{
	int rc;
	__le16 srch_path = 0; /* Null - open root of share */
	u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
	struct cifs_open_parms oparms;
	struct cifs_fid fid;

	oparms.tcon = tcon;
	oparms.desired_access = FILE_READ_ATTRIBUTES;
	oparms.disposition = FILE_OPEN;
	oparms.create_options = 0;
	oparms.fid = &fid;
	oparms.reconnect = false;

	rc = SMB2_open(xid, &oparms, &srch_path, &oplock, NULL, NULL);
	if (rc)
		return rc;
	buf->f_type = SMB2_MAGIC_NUMBER;
	rc = SMB2_QFS_info(xid, tcon, fid.persistent_fid, fid.volatile_fid,
			   buf);
	SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
	return rc;
}

static bool
smb2_compare_fids(struct cifsFileInfo *ob1, struct cifsFileInfo *ob2)
{
	return ob1->fid.persistent_fid == ob2->fid.persistent_fid &&
	       ob1->fid.volatile_fid == ob2->fid.volatile_fid;
}

static int
smb2_mand_lock(const unsigned int xid, struct cifsFileInfo *cfile, __u64 offset,
	       __u64 length, __u32 type, int lock, int unlock, bool wait)
{
	if (unlock && !lock)
		type = SMB2_LOCKFLAG_UNLOCK;
	return SMB2_lock(xid, tlink_tcon(cfile->tlink),
			 cfile->fid.persistent_fid, cfile->fid.volatile_fid,
			 current->tgid, length, offset, type, wait);
}

static void
smb2_get_lease_key(struct inode *inode, struct cifs_fid *fid)
{
	memcpy(fid->lease_key, CIFS_I(inode)->lease_key, SMB2_LEASE_KEY_SIZE);
}

static void
smb2_set_lease_key(struct inode *inode, struct cifs_fid *fid)
{
	memcpy(CIFS_I(inode)->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
}

static void
smb2_new_lease_key(struct cifs_fid *fid)
{
	get_random_bytes(fid->lease_key, SMB2_LEASE_KEY_SIZE);
}

static int
smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
		   const char *full_path, char **target_path,
		   struct cifs_sb_info *cifs_sb)
{
	int rc;
	__le16 *utf16_path;
	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
	struct cifs_open_parms oparms;
	struct cifs_fid fid;
	struct smb2_err_rsp *err_buf = NULL;
	struct smb2_symlink_err_rsp *symlink;
	unsigned int sub_len, sub_offset;

	cifs_dbg(FYI, "%s: path: %s\n", __func__, full_path);

	utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
	if (!utf16_path)
		return -ENOMEM;

	oparms.tcon = tcon;
	oparms.desired_access = FILE_READ_ATTRIBUTES;
	oparms.disposition = FILE_OPEN;
	oparms.create_options = 0;
	oparms.fid = &fid;
	oparms.reconnect = false;

	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, &err_buf);

	if (!rc || !err_buf) {
		kfree(utf16_path);
		return -ENOENT;
	}
	/* open must fail on symlink - reset rc */
	rc = 0;
	symlink = (struct smb2_symlink_err_rsp *)err_buf->ErrorData;
	sub_len = le16_to_cpu(symlink->SubstituteNameLength);
	sub_offset = le16_to_cpu(symlink->SubstituteNameOffset);
	*target_path = cifs_strndup_from_utf16(
				(char *)symlink->PathBuffer + sub_offset,
				sub_len, true, cifs_sb->local_nls);
	if (!(*target_path)) {
		kfree(utf16_path);
		return -ENOMEM;
	}
	convert_delimiter(*target_path, '/');
	cifs_dbg(FYI, "%s: target path: %s\n", __func__, *target_path);
	kfree(utf16_path);
	return rc;
}

static void
smb2_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
		      unsigned int epoch, bool *purge_cache)
{
	oplock &= 0xFF;
	if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
		return;
	if (oplock == SMB2_OPLOCK_LEVEL_BATCH) {
		cinode->oplock = CIFS_CACHE_RHW_FLG;
		cifs_dbg(FYI, "Batch Oplock granted on inode %p\n",
			 &cinode->vfs_inode);
	} else if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE) {
		cinode->oplock = CIFS_CACHE_RW_FLG;
		cifs_dbg(FYI, "Exclusive Oplock granted on inode %p\n",
			 &cinode->vfs_inode);
	} else if (oplock == SMB2_OPLOCK_LEVEL_II) {
		cinode->oplock = CIFS_CACHE_READ_FLG;
		cifs_dbg(FYI, "Level II Oplock granted on inode %p\n",
			 &cinode->vfs_inode);
	} else
		cinode->oplock = 0;
}

static void
smb21_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
		       unsigned int epoch, bool *purge_cache)
{
	char message[5] = {0};

	oplock &= 0xFF;
	if (oplock == SMB2_OPLOCK_LEVEL_NOCHANGE)
		return;

	cinode->oplock = 0;
	if (oplock & SMB2_LEASE_READ_CACHING_HE) {
		cinode->oplock |= CIFS_CACHE_READ_FLG;
		strcat(message, "R");
	}
	if (oplock & SMB2_LEASE_HANDLE_CACHING_HE) {
		cinode->oplock |= CIFS_CACHE_HANDLE_FLG;
		strcat(message, "H");
	}
	if (oplock & SMB2_LEASE_WRITE_CACHING_HE) {
		cinode->oplock |= CIFS_CACHE_WRITE_FLG;
		strcat(message, "W");
	}
	if (!cinode->oplock)
		strcat(message, "None");
	cifs_dbg(FYI, "%s Lease granted on inode %p\n", message,
		 &cinode->vfs_inode);
}

static void
smb3_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
		      unsigned int epoch, bool *purge_cache)
{
	unsigned int old_oplock = cinode->oplock;

	smb21_set_oplock_level(cinode, oplock, epoch, purge_cache);

	if (purge_cache) {
		*purge_cache = false;
		if (old_oplock == CIFS_CACHE_READ_FLG) {
			if (cinode->oplock == CIFS_CACHE_READ_FLG &&
			    (epoch - cinode->epoch > 0))
				*purge_cache = true;
			else if (cinode->oplock == CIFS_CACHE_RH_FLG &&
				 (epoch - cinode->epoch > 1))
				*purge_cache = true;
			else if (cinode->oplock == CIFS_CACHE_RHW_FLG &&
				 (epoch - cinode->epoch > 1))
				*purge_cache = true;
			else if (cinode->oplock == 0 &&
				 (epoch - cinode->epoch > 0))
				*purge_cache = true;
		} else if (old_oplock == CIFS_CACHE_RH_FLG) {
			if (cinode->oplock == CIFS_CACHE_RH_FLG &&
			    (epoch - cinode->epoch > 0))
				*purge_cache = true;
			else if (cinode->oplock == CIFS_CACHE_RHW_FLG &&
				 (epoch - cinode->epoch > 1))
				*purge_cache = true;
		}
		cinode->epoch = epoch;
	}
}

static bool
smb2_is_read_op(__u32 oplock)
{
	return oplock == SMB2_OPLOCK_LEVEL_II;
}

static bool
smb21_is_read_op(__u32 oplock)
{
	return (oplock & SMB2_LEASE_READ_CACHING_HE) &&
	       !(oplock & SMB2_LEASE_WRITE_CACHING_HE);
}

static __le32
map_oplock_to_lease(u8 oplock)
{
	if (oplock == SMB2_OPLOCK_LEVEL_EXCLUSIVE)
		return SMB2_LEASE_WRITE_CACHING | SMB2_LEASE_READ_CACHING;
	else if (oplock == SMB2_OPLOCK_LEVEL_II)
		return SMB2_LEASE_READ_CACHING;
	else if (oplock == SMB2_OPLOCK_LEVEL_BATCH)
		return SMB2_LEASE_HANDLE_CACHING | SMB2_LEASE_READ_CACHING |
		       SMB2_LEASE_WRITE_CACHING;
	return 0;
}

static char *
smb2_create_lease_buf(u8 *lease_key, u8 oplock)
{
	struct create_lease *buf;

	buf = kzalloc(sizeof(struct create_lease), GFP_KERNEL);
	if (!buf)
		return NULL;

	buf->lcontext.LeaseKeyLow = cpu_to_le64(*((u64 *)lease_key));
	buf->lcontext.LeaseKeyHigh = cpu_to_le64(*((u64 *)(lease_key + 8)));
	buf->lcontext.LeaseState = map_oplock_to_lease(oplock);

	buf->ccontext.DataOffset = cpu_to_le16(offsetof
					(struct create_lease, lcontext));
	buf->ccontext.DataLength = cpu_to_le32(sizeof(struct lease_context));
	buf->ccontext.NameOffset = cpu_to_le16(offsetof
				(struct create_lease, Name));
	buf->ccontext.NameLength = cpu_to_le16(4);
	buf->Name[0] = 'R';
	buf->Name[1] = 'q';
	buf->Name[2] = 'L';
	buf->Name[3] = 's';
	return (char *)buf;
}

static char *
smb3_create_lease_buf(u8 *lease_key, u8 oplock)
{
	struct create_lease_v2 *buf;

	buf = kzalloc(sizeof(struct create_lease_v2), GFP_KERNEL);
	if (!buf)
		return NULL;

	buf->lcontext.LeaseKeyLow = cpu_to_le64(*((u64 *)lease_key));
	buf->lcontext.LeaseKeyHigh = cpu_to_le64(*((u64 *)(lease_key + 8)));
	buf->lcontext.LeaseState = map_oplock_to_lease(oplock);

	buf->ccontext.DataOffset = cpu_to_le16(offsetof
					(struct create_lease_v2, lcontext));
	buf->ccontext.DataLength = cpu_to_le32(sizeof(struct lease_context_v2));
	buf->ccontext.NameOffset = cpu_to_le16(offsetof
				(struct create_lease_v2, Name));
	buf->ccontext.NameLength = cpu_to_le16(4);
	buf->Name[0] = 'R';
	buf->Name[1] = 'q';
	buf->Name[2] = 'L';
	buf->Name[3] = 's';
	return (char *)buf;
}

static __u8
smb2_parse_lease_buf(void *buf, unsigned int *epoch)
{
	struct create_lease *lc = (struct create_lease *)buf;

	*epoch = 0; /* not used */
	if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
		return SMB2_OPLOCK_LEVEL_NOCHANGE;
	return le32_to_cpu(lc->lcontext.LeaseState);
}

static __u8
smb3_parse_lease_buf(void *buf, unsigned int *epoch)
{
	struct create_lease_v2 *lc = (struct create_lease_v2 *)buf;

	*epoch = le16_to_cpu(lc->lcontext.Epoch);
	if (lc->lcontext.LeaseFlags & SMB2_LEASE_FLAG_BREAK_IN_PROGRESS)
		return SMB2_OPLOCK_LEVEL_NOCHANGE;
	return le32_to_cpu(lc->lcontext.LeaseState);
}

struct smb_version_operations smb20_operations = {
	.compare_fids = smb2_compare_fids,
	.setup_request = smb2_setup_request,
	.setup_async_request = smb2_setup_async_request,
	.check_receive = smb2_check_receive,
	.add_credits = smb2_add_credits,
	.set_credits = smb2_set_credits,
	.get_credits_field = smb2_get_credits_field,
	.get_credits = smb2_get_credits,
	.get_next_mid = smb2_get_next_mid,
	.read_data_offset = smb2_read_data_offset,
	.read_data_length = smb2_read_data_length,
	.map_error = map_smb2_to_linux_error,
	.find_mid = smb2_find_mid,
	.check_message = smb2_check_message,
	.dump_detail = smb2_dump_detail,
	.clear_stats = smb2_clear_stats,
	.print_stats = smb2_print_stats,
	.is_oplock_break = smb2_is_valid_oplock_break,
	.need_neg = smb2_need_neg,
	.negotiate = smb2_negotiate,
	.negotiate_wsize = smb2_negotiate_wsize,
	.negotiate_rsize = smb2_negotiate_rsize,
	.sess_setup = SMB2_sess_setup,
	.logoff = SMB2_logoff,
	.tree_connect = SMB2_tcon,
	.tree_disconnect = SMB2_tdis,
	.qfs_tcon = smb2_qfs_tcon,
	.is_path_accessible = smb2_is_path_accessible,
	.can_echo = smb2_can_echo,
	.echo = SMB2_echo,
	.query_path_info = smb2_query_path_info,
	.get_srv_inum = smb2_get_srv_inum,
	.query_file_info = smb2_query_file_info,
	.set_path_size = smb2_set_path_size,
	.set_file_size = smb2_set_file_size,
	.set_file_info = smb2_set_file_info,
	.set_compression = smb2_set_compression,
	.mkdir = smb2_mkdir,
	.mkdir_setinfo = smb2_mkdir_setinfo,
	.rmdir = smb2_rmdir,
	.unlink = smb2_unlink,
	.rename = smb2_rename_path,
	.create_hardlink = smb2_create_hardlink,
	.query_symlink = smb2_query_symlink,
	.open = smb2_open_file,
	.set_fid = smb2_set_fid,
	.close = smb2_close_file,
	.flush = smb2_flush_file,
	.async_readv = smb2_async_readv,
	.async_writev = smb2_async_writev,
	.sync_read = smb2_sync_read,
	.sync_write = smb2_sync_write,
	.query_dir_first = smb2_query_dir_first,
	.query_dir_next = smb2_query_dir_next,
	.close_dir = smb2_close_dir,
	.calc_smb_size = smb2_calc_size,
	.is_status_pending = smb2_is_status_pending,
	.oplock_response = smb2_oplock_response,
	.queryfs = smb2_queryfs,
	.mand_lock = smb2_mand_lock,
	.mand_unlock_range = smb2_unlock_range,
	.push_mand_locks = smb2_push_mandatory_locks,
	.get_lease_key = smb2_get_lease_key,
	.set_lease_key = smb2_set_lease_key,
	.new_lease_key = smb2_new_lease_key,
	.calc_signature = smb2_calc_signature,
	.is_read_op = smb2_is_read_op,
	.set_oplock_level = smb2_set_oplock_level,
	.create_lease_buf = smb2_create_lease_buf,
	.parse_lease_buf = smb2_parse_lease_buf,
};

struct smb_version_operations smb21_operations = {
	.compare_fids = smb2_compare_fids,
	.setup_request = smb2_setup_request,
	.setup_async_request = smb2_setup_async_request,
	.check_receive = smb2_check_receive,
	.add_credits = smb2_add_credits,
	.set_credits = smb2_set_credits,
	.get_credits_field = smb2_get_credits_field,
	.get_credits = smb2_get_credits,
	.get_next_mid = smb2_get_next_mid,
	.read_data_offset = smb2_read_data_offset,
	.read_data_length = smb2_read_data_length,
	.map_error = map_smb2_to_linux_error,
	.find_mid = smb2_find_mid,
	.check_message = smb2_check_message,
	.dump_detail = smb2_dump_detail,
	.clear_stats = smb2_clear_stats,
	.print_stats = smb2_print_stats,
	.is_oplock_break = smb2_is_valid_oplock_break,
	.need_neg = smb2_need_neg,
	.negotiate = smb2_negotiate,
	.negotiate_wsize = smb2_negotiate_wsize,
	.negotiate_rsize = smb2_negotiate_rsize,
	.sess_setup = SMB2_sess_setup,
	.logoff = SMB2_logoff,
	.tree_connect = SMB2_tcon,
	.tree_disconnect = SMB2_tdis,
	.qfs_tcon = smb2_qfs_tcon,
	.is_path_accessible = smb2_is_path_accessible,
	.can_echo = smb2_can_echo,
	.echo = SMB2_echo,
	.query_path_info = smb2_query_path_info,
	.get_srv_inum = smb2_get_srv_inum,
	.query_file_info = smb2_query_file_info,
	.set_path_size = smb2_set_path_size,
	.set_file_size = smb2_set_file_size,
	.set_file_info = smb2_set_file_info,
	.set_compression = smb2_set_compression,
	.mkdir = smb2_mkdir,
	.mkdir_setinfo = smb2_mkdir_setinfo,
	.rmdir = smb2_rmdir,
	.unlink = smb2_unlink,
	.rename = smb2_rename_path,
	.create_hardlink = smb2_create_hardlink,
	.query_symlink = smb2_query_symlink,
	.open = smb2_open_file,
	.set_fid = smb2_set_fid,
	.close = smb2_close_file,
	.flush = smb2_flush_file,
	.async_readv = smb2_async_readv,
	.async_writev = smb2_async_writev,
	.sync_read = smb2_sync_read,
	.sync_write = smb2_sync_write,
	.query_dir_first = smb2_query_dir_first,
	.query_dir_next = smb2_query_dir_next,
	.close_dir = smb2_close_dir,
	.calc_smb_size = smb2_calc_size,
	.is_status_pending = smb2_is_status_pending,
	.oplock_response = smb2_oplock_response,
	.queryfs = smb2_queryfs,
	.mand_lock = smb2_mand_lock,
	.mand_unlock_range = smb2_unlock_range,
	.push_mand_locks = smb2_push_mandatory_locks,
	.get_lease_key = smb2_get_lease_key,
	.set_lease_key = smb2_set_lease_key,
	.new_lease_key = smb2_new_lease_key,
	.calc_signature = smb2_calc_signature,
	.is_read_op = smb21_is_read_op,
	.set_oplock_level = smb21_set_oplock_level,
	.create_lease_buf = smb2_create_lease_buf,
	.parse_lease_buf = smb2_parse_lease_buf,
};

struct smb_version_operations smb30_operations = {
	.compare_fids = smb2_compare_fids,
	.setup_request = smb2_setup_request,
	.setup_async_request = smb2_setup_async_request,
	.check_receive = smb2_check_receive,
	.add_credits = smb2_add_credits,
	.set_credits = smb2_set_credits,
	.get_credits_field = smb2_get_credits_field,
	.get_credits = smb2_get_credits,
	.get_next_mid = smb2_get_next_mid,
	.read_data_offset = smb2_read_data_offset,
	.read_data_length = smb2_read_data_length,
	.map_error = map_smb2_to_linux_error,
	.find_mid = smb2_find_mid,
	.check_message = smb2_check_message,
	.dump_detail = smb2_dump_detail,
	.clear_stats = smb2_clear_stats,
	.print_stats = smb2_print_stats,
	.dump_share_caps = smb2_dump_share_caps,
	.is_oplock_break = smb2_is_valid_oplock_break,
	.need_neg = smb2_need_neg,
	.negotiate = smb2_negotiate,
	.negotiate_wsize = smb2_negotiate_wsize,
	.negotiate_rsize = smb2_negotiate_rsize,
	.sess_setup = SMB2_sess_setup,
	.logoff = SMB2_logoff,
	.tree_connect = SMB2_tcon,
	.tree_disconnect = SMB2_tdis,
	.qfs_tcon = smb2_qfs_tcon,
	.is_path_accessible = smb2_is_path_accessible,
	.can_echo = smb2_can_echo,
	.echo = SMB2_echo,
	.query_path_info = smb2_query_path_info,
	.get_srv_inum = smb2_get_srv_inum,
	.query_file_info = smb2_query_file_info,
	.set_path_size = smb2_set_path_size,
	.set_file_size = smb2_set_file_size,
	.set_file_info = smb2_set_file_info,
	.set_compression = smb2_set_compression,
	.mkdir = smb2_mkdir,
	.mkdir_setinfo = smb2_mkdir_setinfo,
	.rmdir = smb2_rmdir,
	.unlink = smb2_unlink,
	.rename = smb2_rename_path,
	.create_hardlink = smb2_create_hardlink,
	.query_symlink = smb2_query_symlink,
	.open = smb2_open_file,
	.set_fid = smb2_set_fid,
	.close = smb2_close_file,
	.flush = smb2_flush_file,
	.async_readv = smb2_async_readv,
	.async_writev = smb2_async_writev,
	.sync_read = smb2_sync_read,
	.sync_write = smb2_sync_write,
	.query_dir_first = smb2_query_dir_first,
	.query_dir_next = smb2_query_dir_next,
	.close_dir = smb2_close_dir,
	.calc_smb_size = smb2_calc_size,
	.is_status_pending = smb2_is_status_pending,
	.oplock_response = smb2_oplock_response,
	.queryfs = smb2_queryfs,
	.mand_lock = smb2_mand_lock,
	.mand_unlock_range = smb2_unlock_range,
	.push_mand_locks = smb2_push_mandatory_locks,
	.get_lease_key = smb2_get_lease_key,
	.set_lease_key = smb2_set_lease_key,
	.new_lease_key = smb2_new_lease_key,
	.generate_signingkey = generate_smb3signingkey,
	.calc_signature = smb3_calc_signature,
	.is_read_op = smb21_is_read_op,
	.set_oplock_level = smb3_set_oplock_level,
	.create_lease_buf = smb3_create_lease_buf,
	.parse_lease_buf = smb3_parse_lease_buf,
};

struct smb_version_values smb20_values = {
	.version_string = SMB20_VERSION_STRING,
	.protocol_id = SMB20_PROT_ID,
	.req_capabilities = 0, /* MBZ */
	.large_lock_type = 0,
	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
	.shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
	.header_size = sizeof(struct smb2_hdr),
	.max_header_size = MAX_SMB2_HDR_SIZE,
	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
	.lock_cmd = SMB2_LOCK,
	.cap_unix = 0,
	.cap_nt_find = SMB2_NT_FIND,
	.cap_large_files = SMB2_LARGE_FILES,
	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.create_lease_size = sizeof(struct create_lease),
};

struct smb_version_values smb21_values = {
	.version_string = SMB21_VERSION_STRING,
	.protocol_id = SMB21_PROT_ID,
	.req_capabilities = 0, /* MBZ on negotiate req until SMB3 dialect */
	.large_lock_type = 0,
	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
	.shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
	.header_size = sizeof(struct smb2_hdr),
	.max_header_size = MAX_SMB2_HDR_SIZE,
	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
	.lock_cmd = SMB2_LOCK,
	.cap_unix = 0,
	.cap_nt_find = SMB2_NT_FIND,
	.cap_large_files = SMB2_LARGE_FILES,
	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.create_lease_size = sizeof(struct create_lease),
};

struct smb_version_values smb30_values = {
	.version_string = SMB30_VERSION_STRING,
	.protocol_id = SMB30_PROT_ID,
	.req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU,
	.large_lock_type = 0,
	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
	.shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
	.header_size = sizeof(struct smb2_hdr),
	.max_header_size = MAX_SMB2_HDR_SIZE,
	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
	.lock_cmd = SMB2_LOCK,
	.cap_unix = 0,
	.cap_nt_find = SMB2_NT_FIND,
	.cap_large_files = SMB2_LARGE_FILES,
	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.create_lease_size = sizeof(struct create_lease_v2),
};

struct smb_version_values smb302_values = {
	.version_string = SMB302_VERSION_STRING,
	.protocol_id = SMB302_PROT_ID,
	.req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU,
	.large_lock_type = 0,
	.exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
	.shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
	.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
	.header_size = sizeof(struct smb2_hdr),
	.max_header_size = MAX_SMB2_HDR_SIZE,
	.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
	.lock_cmd = SMB2_LOCK,
	.cap_unix = 0,
	.cap_nt_find = SMB2_NT_FIND,
	.cap_large_files = SMB2_LARGE_FILES,
	.signing_enabled = SMB2_NEGOTIATE_SIGNING_ENABLED | SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
	.create_lease_size = sizeof(struct create_lease_v2),
};