Merge tag '5.19-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs client fixes from Steve French:
 "Nine cifs/smb3 client fixes.

  Includes DFS fixes, some cleanup of leagcy SMB1 code, duplicated
  message cleanup and a double free and deadlock fix"

* tag '5.19-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix uninitialized pointer in error case in dfs_cache_get_tgt_share
  cifs: skip trailing separators of prefix paths
  cifs: update internal module number
  cifs: version operations for smb20 unneeded when legacy support disabled
  cifs: do not build smb1ops if legacy support is disabled
  cifs: fix potential deadlock in direct reclaim
  cifs: when extending a file with falloc we should make files not-sparse
  cifs: remove repeated debug message on cifs_put_smb_ses()
  cifs: fix potential double free during failed mount

fs/cifs/Makefile

@@ -8,7 +8,7 @@ obj-$(CONFIG_CIFS) += cifs.o
 cifs-y := trace.o cifsfs.o cifssmb.o cifs_debug.o connect.o dir.o file.o \
 	  inode.o link.o misc.o netmisc.o smbencrypt.o transport.o \
 	  cifs_unicode.o nterr.o cifsencrypt.o \
-	  readdir.o ioctl.o sess.o export.o smb1ops.o unc.o winucase.o \
+	  readdir.o ioctl.o sess.o export.o unc.o winucase.o \
 	  smb2ops.o smb2maperror.o smb2transport.o \
 	  smb2misc.o smb2pdu.o smb2inode.o smb2file.o cifsacl.o fs_context.o \
 	  dns_resolve.o cifs_spnego_negtokeninit.asn1.o asn1.o
@@ -30,3 +30,5 @@ cifs-$(CONFIG_CIFS_FSCACHE) += fscache.o
 cifs-$(CONFIG_CIFS_SMB_DIRECT) += smbdirect.o
 
 cifs-$(CONFIG_CIFS_ROOT) += cifsroot.o
+
+cifs-$(CONFIG_CIFS_ALLOW_INSECURE_LEGACY) += smb1ops.o

fs/cifs/cifs_swn.c

@@ -465,7 +465,7 @@ static int cifs_swn_reconnect(struct cifs_tcon *tcon, struct sockaddr_storage *a
 	int ret = 0;
 
 	/* Store the reconnect address */
-	mutex_lock(&tcon->ses->server->srv_mutex);
+	cifs_server_lock(tcon->ses->server);
 	if (cifs_sockaddr_equal(&tcon->ses->server->dstaddr, addr))
 		goto unlock;
 
@@ -501,7 +501,7 @@ static int cifs_swn_reconnect(struct cifs_tcon *tcon, struct sockaddr_storage *a
 	cifs_signal_cifsd_for_reconnect(tcon->ses->server, false);
 
 unlock:
-	mutex_unlock(&tcon->ses->server->srv_mutex);
+	cifs_server_unlock(tcon->ses->server);
 
 	return ret;
 }

fs/cifs/cifsencrypt.c

@@ -236,9 +236,9 @@ int cifs_verify_signature(struct smb_rqst *rqst,
 					cpu_to_le32(expected_sequence_number);
 	cifs_pdu->Signature.Sequence.Reserved = 0;
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 	rc = cifs_calc_signature(rqst, server, what_we_think_sig_should_be);
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	if (rc)
 		return rc;
@@ -626,7 +626,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 
 	memcpy(ses->auth_key.response + baselen, tiblob, tilen);
 
-	mutex_lock(&ses->server->srv_mutex);
+	cifs_server_lock(ses->server);
 
 	rc = cifs_alloc_hash("hmac(md5)",
 			     &ses->server->secmech.hmacmd5,
@@ -678,7 +678,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 		cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
 
 unlock:
-	mutex_unlock(&ses->server->srv_mutex);
+	cifs_server_unlock(ses->server);
 setup_ntlmv2_rsp_ret:
 	kfree(tiblob);
 

fs/cifs/cifsfs.c

@@ -838,7 +838,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
 	      int flags, struct smb3_fs_context *old_ctx)
 {
 	int rc;
-	struct super_block *sb;
+	struct super_block *sb = NULL;
 	struct cifs_sb_info *cifs_sb = NULL;
 	struct cifs_mnt_data mnt_data;
 	struct dentry *root;
@@ -934,10 +934,12 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
 	return root;
 out:
 	if (cifs_sb) {
+		if (!sb || IS_ERR(sb)) {  /* otherwise kill_sb will handle */
 			kfree(cifs_sb->prepath);
 			smb3_cleanup_fs_context(cifs_sb->ctx);
 			kfree(cifs_sb);
 		}
+	}
 	return root;
 }
 

fs/cifs/cifsfs.h

@@ -152,6 +152,7 @@ extern struct dentry *cifs_smb3_do_mount(struct file_system_type *fs_type,
 extern const struct export_operations cifs_export_ops;
 #endif /* CONFIG_CIFS_NFSD_EXPORT */
 
-#define SMB3_PRODUCT_BUILD 35
-#define CIFS_VERSION   "2.36"
+/* when changing internal version - update following two lines at same time */
+#define SMB3_PRODUCT_BUILD 37
+#define CIFS_VERSION   "2.37"
 #endif				/* _CIFSFS_H */

fs/cifs/cifsglob.h

@@ -16,6 +16,7 @@
 #include <linux/mempool.h>
 #include <linux/workqueue.h>
 #include <linux/utsname.h>
+#include <linux/sched/mm.h>
 #include <linux/netfs.h>
 #include "cifs_fs_sb.h"
 #include "cifsacl.h"
@@ -628,7 +629,8 @@ struct TCP_Server_Info {
 	unsigned int in_flight;  /* number of requests on the wire to server */
 	unsigned int max_in_flight; /* max number of requests that were on wire */
 	spinlock_t req_lock;  /* protect the two values above */
-	struct mutex srv_mutex;
+	struct mutex _srv_mutex;
+	unsigned int nofs_flag;
 	struct task_struct *tsk;
 	char server_GUID[16];
 	__u16 sec_mode;
@@ -743,6 +745,22 @@ struct TCP_Server_Info {
 #endif
 };
 
+static inline void cifs_server_lock(struct TCP_Server_Info *server)
+{
+	unsigned int nofs_flag = memalloc_nofs_save();
+
+	mutex_lock(&server->_srv_mutex);
+	server->nofs_flag = nofs_flag;
+}
+
+static inline void cifs_server_unlock(struct TCP_Server_Info *server)
+{
+	unsigned int nofs_flag = server->nofs_flag;
+
+	mutex_unlock(&server->_srv_mutex);
+	memalloc_nofs_restore(nofs_flag);
+}
+
 struct cifs_credits {
 	unsigned int value;
 	unsigned int instance;
@@ -1945,11 +1963,13 @@ extern mempool_t *cifs_mid_poolp;
 
 /* Operations for different SMB versions */
 #define SMB1_VERSION_STRING	"1.0"
+#define SMB20_VERSION_STRING    "2.0"
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 extern struct smb_version_operations smb1_operations;
 extern struct smb_version_values smb1_values;
-#define SMB20_VERSION_STRING	"2.0"
 extern struct smb_version_operations smb20_operations;
 extern struct smb_version_values smb20_values;
+#endif /* CIFS_ALLOW_INSECURE_LEGACY */
 #define SMB21_VERSION_STRING	"2.1"
 extern struct smb_version_operations smb21_operations;
 extern struct smb_version_values smb21_values;

fs/cifs/connect.c

@@ -148,7 +148,7 @@ static void cifs_resolve_server(struct work_struct *work)
 	struct TCP_Server_Info *server = container_of(work,
 					struct TCP_Server_Info, resolve.work);
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 
 	/*
 	 * Resolve the hostname again to make sure that IP address is up-to-date.
@@ -159,7 +159,7 @@ static void cifs_resolve_server(struct work_struct *work)
 				__func__, rc);
 	}
 
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 }
 
 /*
@@ -267,7 +267,7 @@ cifs_abort_connection(struct TCP_Server_Info *server)
 
 	/* do not want to be sending data on a socket we are freeing */
 	cifs_dbg(FYI, "%s: tearing down socket\n", __func__);
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 	if (server->ssocket) {
 		cifs_dbg(FYI, "State: 0x%x Flags: 0x%lx\n", server->ssocket->state,
 			 server->ssocket->flags);
@@ -296,7 +296,7 @@ cifs_abort_connection(struct TCP_Server_Info *server)
 		mid->mid_flags |= MID_DELETED;
 	}
 	spin_unlock(&GlobalMid_Lock);
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
 	list_for_each_entry_safe(mid, nmid, &retry_list, qhead) {
@@ -306,9 +306,9 @@ cifs_abort_connection(struct TCP_Server_Info *server)
 	}
 
 	if (cifs_rdma_enabled(server)) {
-		mutex_lock(&server->srv_mutex);
+		cifs_server_lock(server);
 		smbd_destroy(server);
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 	}
 }
 
@@ -359,7 +359,7 @@ static int __cifs_reconnect(struct TCP_Server_Info *server,
 
 	do {
 		try_to_freeze();
-		mutex_lock(&server->srv_mutex);
+		cifs_server_lock(server);
 
 		if (!cifs_swn_set_server_dstaddr(server)) {
 			/* resolve the hostname again to make sure that IP address is up-to-date */
@@ -372,7 +372,7 @@ static int __cifs_reconnect(struct TCP_Server_Info *server,
 		else
 			rc = generic_ip_connect(server);
 		if (rc) {
-			mutex_unlock(&server->srv_mutex);
+			cifs_server_unlock(server);
 			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
 			msleep(3000);
 		} else {
@@ -383,7 +383,7 @@ static int __cifs_reconnect(struct TCP_Server_Info *server,
 				server->tcpStatus = CifsNeedNegotiate;
 			spin_unlock(&cifs_tcp_ses_lock);
 			cifs_swn_reset_server_dstaddr(server);
-			mutex_unlock(&server->srv_mutex);
+			cifs_server_unlock(server);
 			mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 		}
 	} while (server->tcpStatus == CifsNeedReconnect);
@@ -488,12 +488,12 @@ static int reconnect_dfs_server(struct TCP_Server_Info *server)
 
 	do {
 		try_to_freeze();
-		mutex_lock(&server->srv_mutex);
+		cifs_server_lock(server);
 
 		rc = reconnect_target_unlocked(server, &tl, &target_hint);
 		if (rc) {
 			/* Failed to reconnect socket */
-			mutex_unlock(&server->srv_mutex);
+			cifs_server_unlock(server);
 			cifs_dbg(FYI, "%s: reconnect error %d\n", __func__, rc);
 			msleep(3000);
 			continue;
@@ -510,7 +510,7 @@ static int reconnect_dfs_server(struct TCP_Server_Info *server)
 			server->tcpStatus = CifsNeedNegotiate;
 		spin_unlock(&cifs_tcp_ses_lock);
 		cifs_swn_reset_server_dstaddr(server);
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
 	} while (server->tcpStatus == CifsNeedReconnect);
 
@@ -1565,7 +1565,7 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx,
 	init_waitqueue_head(&tcp_ses->response_q);
 	init_waitqueue_head(&tcp_ses->request_q);
 	INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
-	mutex_init(&tcp_ses->srv_mutex);
+	mutex_init(&tcp_ses->_srv_mutex);
 	memcpy(tcp_ses->workstation_RFC1001_name,
 		ctx->source_rfc1001_name, RFC1001_NAME_LEN_WITH_NULL);
 	memcpy(tcp_ses->server_RFC1001_name,
@@ -1845,7 +1845,6 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
 	unsigned int rc, xid;
 	unsigned int chan_count;
 	struct TCP_Server_Info *server = ses->server;
-	cifs_dbg(FYI, "%s: ses_count=%d\n", __func__, ses->ses_count);
 
 	spin_lock(&cifs_tcp_ses_lock);
 	if (ses->ses_status == SES_EXITING) {

fs/cifs/dfs_cache.c

@@ -1229,6 +1229,30 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id)
 	kref_put(&mg->refcount, mount_group_release);
 }
 
+/* Extract share from DFS target and return a pointer to prefix path or NULL */
+static const char *parse_target_share(const char *target, char **share)
+{
+	const char *s, *seps = "/\\";
+	size_t len;
+
+	s = strpbrk(target + 1, seps);
+	if (!s)
+		return ERR_PTR(-EINVAL);
+
+	len = strcspn(s + 1, seps);
+	if (!len)
+		return ERR_PTR(-EINVAL);
+	s += len;
+
+	len = s - target + 1;
+	*share = kstrndup(target, len, GFP_KERNEL);
+	if (!*share)
+		return ERR_PTR(-ENOMEM);
+
+	s = target + len;
+	return s + strspn(s, seps);
+}
+
 /**
  * dfs_cache_get_tgt_share - parse a DFS target
  *
@@ -1242,56 +1266,46 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id)
 int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,
 			    char **prefix)
 {
-	char *s, sep, *p;
-	size_t len;
-	size_t plen1, plen2;
+	char sep;
+	char *target_share;
+	char *ppath = NULL;
+	const char *target_ppath, *dfsref_ppath;
+	size_t target_pplen, dfsref_pplen;
+	size_t len, c;
 
 	if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)
 		return -EINVAL;
 
-	*share = NULL;
-	*prefix = NULL;
-
 	sep = it->it_name[0];
 	if (sep != '\\' && sep != '/')
 		return -EINVAL;
 
-	s = strchr(it->it_name + 1, sep);
-	if (!s)
-		return -EINVAL;
+	target_ppath = parse_target_share(it->it_name, &target_share);
+	if (IS_ERR(target_ppath))
+		return PTR_ERR(target_ppath);
 
-	/* point to prefix in target node */
-	s = strchrnul(s + 1, sep);
+	/* point to prefix in DFS referral path */
+	dfsref_ppath = path + it->it_path_consumed;
+	dfsref_ppath += strspn(dfsref_ppath, "/\\");
 
-	/* extract target share */
-	*share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL);
-	if (!*share)
-		return -ENOMEM;
+	target_pplen = strlen(target_ppath);
+	dfsref_pplen = strlen(dfsref_ppath);
 
-	/* skip separator */
-	if (*s)
-		s++;
-	/* point to prefix in DFS path */
-	p = path + it->it_path_consumed;
-	if (*p == sep)
-		p++;
-
-	/* merge prefix paths from DFS path and target node */
-	plen1 = it->it_name + strlen(it->it_name) - s;
-	plen2 = path + strlen(path) - p;
-	if (plen1 || plen2) {
-		len = plen1 + plen2 + 2;
-		*prefix = kmalloc(len, GFP_KERNEL);
-		if (!*prefix) {
-			kfree(*share);
-			*share = NULL;
+	/* merge prefix paths from DFS referral path and target node */
+	if (target_pplen || dfsref_pplen) {
+		len = target_pplen + dfsref_pplen + 2;
+		ppath = kzalloc(len, GFP_KERNEL);
+		if (!ppath) {
+			kfree(target_share);
 			return -ENOMEM;
 		}
-		if (plen1)
-			scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p);
-		else
-			strscpy(*prefix, p, len);
+		c = strscpy(ppath, target_ppath, len);
+		if (c && dfsref_pplen)
+			ppath[c] = sep;
+		strlcat(ppath, dfsref_ppath, len);
 	}
+	*share = target_share;
+	*prefix = ppath;
 	return 0;
 }
 
@@ -1327,9 +1341,9 @@ static bool target_share_equal(struct TCP_Server_Info *server, const char *s1, c
 		cifs_dbg(VFS, "%s: failed to convert address \'%s\'. skip address matching.\n",
 			 __func__, ip);
 	} else {
-		mutex_lock(&server->srv_mutex);
+		cifs_server_lock(server);
 		match = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, &sa);
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 	}
 
 	kfree(ip);

fs/cifs/sess.c

@@ -1120,14 +1120,14 @@ sess_establish_session(struct sess_data *sess_data)
 	struct cifs_ses *ses = sess_data->ses;
 	struct TCP_Server_Info *server = sess_data->server;
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 	if (!server->session_estab) {
 		if (server->sign) {
 			server->session_key.response =
 				kmemdup(ses->auth_key.response,
 				ses->auth_key.len, GFP_KERNEL);
 			if (!server->session_key.response) {
-				mutex_unlock(&server->srv_mutex);
+				cifs_server_unlock(server);
 				return -ENOMEM;
 			}
 			server->session_key.len =
@@ -1136,7 +1136,7 @@ sess_establish_session(struct sess_data *sess_data)
 		server->sequence_number = 0x2;
 		server->session_estab = true;
 	}
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	cifs_dbg(FYI, "CIFS session established successfully\n");
 	return 0;

fs/cifs/smb1ops.c

@@ -38,10 +38,10 @@ send_nt_cancel(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 	in_buf->WordCount = 0;
 	put_bcc(0, in_buf);
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 	rc = cifs_sign_smb(in_buf, server, &mid->sequence_number);
 	if (rc) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		return rc;
 	}
 
@@ -55,7 +55,7 @@ send_nt_cancel(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 	if (rc < 0)
 		server->sequence_number--;
 
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	cifs_dbg(FYI, "issued NT_CANCEL for mid %u, rc = %d\n",
 		 get_mid(in_buf), rc);

fs/cifs/smb2ops.c

@@ -3859,7 +3859,7 @@ static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
 		if (rc)
 			goto out;
 
-		if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0)
+		if (cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE)
 			smb2_set_sparse(xid, tcon, cfile, inode, false);
 
 		eof = cpu_to_le64(off + len);
@@ -4345,11 +4345,13 @@ smb3_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock,
 	}
 }
 
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 static bool
 smb2_is_read_op(__u32 oplock)
 {
 	return oplock == SMB2_OPLOCK_LEVEL_II;
 }
+#endif /* CIFS_ALLOW_INSECURE_LEGACY */
 
 static bool
 smb21_is_read_op(__u32 oplock)
@@ -5448,7 +5450,7 @@ smb2_make_node(unsigned int xid, struct inode *inode,
 	return rc;
 }
 
-
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 struct smb_version_operations smb20_operations = {
 	.compare_fids = smb2_compare_fids,
 	.setup_request = smb2_setup_request,
@@ -5547,6 +5549,7 @@ struct smb_version_operations smb20_operations = {
 	.is_status_io_timeout = smb2_is_status_io_timeout,
 	.is_network_name_deleted = smb2_is_network_name_deleted,
 };
+#endif /* CIFS_ALLOW_INSECURE_LEGACY */
 
 struct smb_version_operations smb21_operations = {
 	.compare_fids = smb2_compare_fids,
@@ -5878,6 +5881,7 @@ struct smb_version_operations smb311_operations = {
 	.is_network_name_deleted = smb2_is_network_name_deleted,
 };
 
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
 struct smb_version_values smb20_values = {
 	.version_string = SMB20_VERSION_STRING,
 	.protocol_id = SMB20_PROT_ID,
@@ -5898,6 +5902,7 @@ struct smb_version_values smb20_values = {
 	.signing_required = SMB2_NEGOTIATE_SIGNING_REQUIRED,
 	.create_lease_size = sizeof(struct create_lease),
 };
+#endif /* ALLOW_INSECURE_LEGACY */
 
 struct smb_version_values smb21_values = {
 	.version_string = SMB21_VERSION_STRING,

fs/cifs/smb2pdu.c

@@ -1369,13 +1369,13 @@ SMB2_sess_establish_session(struct SMB2_sess_data *sess_data)
 	struct cifs_ses *ses = sess_data->ses;
 	struct TCP_Server_Info *server = sess_data->server;
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 	if (server->ops->generate_signingkey) {
 		rc = server->ops->generate_signingkey(ses, server);
 		if (rc) {
 			cifs_dbg(FYI,
 				"SMB3 session key generation failed\n");
-			mutex_unlock(&server->srv_mutex);
+			cifs_server_unlock(server);
 			return rc;
 		}
 	}
@@ -1383,7 +1383,7 @@ SMB2_sess_establish_session(struct SMB2_sess_data *sess_data)
 		server->sequence_number = 0x2;
 		server->session_estab = true;
 	}
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	cifs_dbg(FYI, "SMB2/3 session established successfully\n");
 	return rc;

fs/cifs/smbdirect.c

@@ -1382,9 +1382,9 @@ void smbd_destroy(struct TCP_Server_Info *server)
 	log_rdma_event(INFO, "freeing mr list\n");
 	wake_up_interruptible_all(&info->wait_mr);
 	while (atomic_read(&info->mr_used_count)) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		msleep(1000);
-		mutex_lock(&server->srv_mutex);
+		cifs_server_lock(server);
 	}
 	destroy_mr_list(info);
 

fs/cifs/transport.c

@@ -822,7 +822,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 	} else
 		instance = exist_credits->instance;
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 
 	/*
 	 * We can't use credits obtained from the previous session to send this
@@ -830,14 +830,14 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 	 * return -EAGAIN in such cases to let callers handle it.
 	 */
 	if (instance != server->reconnect_instance) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		add_credits_and_wake_if(server, &credits, optype);
 		return -EAGAIN;
 	}
 
 	mid = server->ops->setup_async_request(server, rqst);
 	if (IS_ERR(mid)) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		add_credits_and_wake_if(server, &credits, optype);
 		return PTR_ERR(mid);
 	}
@@ -868,7 +868,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 		cifs_delete_mid(mid);
 	}
 
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	if (rc == 0)
 		return 0;
@@ -1109,7 +1109,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 	 * of smb data.
 	 */
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 
 	/*
 	 * All the parts of the compound chain belong obtained credits from the
@@ -1119,7 +1119,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 	 * handle it.
 	 */
 	if (instance != server->reconnect_instance) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		for (j = 0; j < num_rqst; j++)
 			add_credits(server, &credits[j], optype);
 		return -EAGAIN;
@@ -1131,7 +1131,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 			revert_current_mid(server, i);
 			for (j = 0; j < i; j++)
 				cifs_delete_mid(midQ[j]);
-			mutex_unlock(&server->srv_mutex);
+			cifs_server_unlock(server);
 
 			/* Update # of requests on wire to server */
 			for (j = 0; j < num_rqst; j++)
@@ -1163,7 +1163,7 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 		server->sequence_number -= 2;
 	}
 
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	/*
 	 * If sending failed for some reason or it is an oplock break that we
@@ -1190,9 +1190,9 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 	if ((ses->ses_status == SES_NEW) || (optype & CIFS_NEG_OP) || (optype & CIFS_SESS_OP)) {
 		spin_unlock(&cifs_tcp_ses_lock);
 
-		mutex_lock(&server->srv_mutex);
+		cifs_server_lock(server);
 		smb311_update_preauth_hash(ses, server, rqst[0].rq_iov, rqst[0].rq_nvec);
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 
 		spin_lock(&cifs_tcp_ses_lock);
 	}
@@ -1266,9 +1266,9 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 			.iov_len = resp_iov[0].iov_len
 		};
 		spin_unlock(&cifs_tcp_ses_lock);
-		mutex_lock(&server->srv_mutex);
+		cifs_server_lock(server);
 		smb311_update_preauth_hash(ses, server, &iov, 1);
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		spin_lock(&cifs_tcp_ses_lock);
 	}
 	spin_unlock(&cifs_tcp_ses_lock);
@@ -1385,11 +1385,11 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
 	   and avoid races inside tcp sendmsg code that could cause corruption
 	   of smb data */
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 
 	rc = allocate_mid(ses, in_buf, &midQ);
 	if (rc) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		/* Update # of requests on wire to server */
 		add_credits(server, &credits, 0);
 		return rc;
@@ -1397,7 +1397,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
 
 	rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
 	if (rc) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		goto out;
 	}
 
@@ -1411,7 +1411,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
 	if (rc < 0)
 		server->sequence_number -= 2;
 
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	if (rc < 0)
 		goto out;
@@ -1530,18 +1530,18 @@ SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
 	   and avoid races inside tcp sendmsg code that could cause corruption
 	   of smb data */
 
-	mutex_lock(&server->srv_mutex);
+	cifs_server_lock(server);
 
 	rc = allocate_mid(ses, in_buf, &midQ);
 	if (rc) {
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		return rc;
 	}
 
 	rc = cifs_sign_smb(in_buf, server, &midQ->sequence_number);
 	if (rc) {
 		cifs_delete_mid(midQ);
-		mutex_unlock(&server->srv_mutex);
+		cifs_server_unlock(server);
 		return rc;
 	}
 
@@ -1554,7 +1554,7 @@ SendReceiveBlockingLock(const unsigned int xid, struct cifs_tcon *tcon,
 	if (rc < 0)
 		server->sequence_number -= 2;
 
-	mutex_unlock(&server->srv_mutex);
+	cifs_server_unlock(server);
 
 	if (rc < 0) {
 		cifs_delete_mid(midQ);