Update 4.2 sources from stable (v4.2.8-ckt12)

sources/4.2/cifs_debug.c

@@ -50,7 +50,7 @@ void cifs_vfs_err(const char *fmt, ...)
 	vaf.fmt = fmt;
 	vaf.va = &args;
 
-	pr_err("CIFS VFS: %pV", &vaf);
+	pr_err_ratelimited("CIFS VFS: %pV", &vaf);
 
 	va_end(args);
 }

sources/4.2/cifs_debug.h

@@ -51,14 +51,13 @@ __printf(1, 2) void cifs_vfs_err(const char *fmt, ...);
 /* information message: e.g., configuration, major event */
 #define cifs_dbg(type, fmt, ...)					\
 do {									\
-	if (type == FYI) {						\
-		if (cifsFYI & CIFS_INFO) {				\
-			pr_debug("%s: " fmt, __FILE__, ##__VA_ARGS__);	\
-		}							\
+	if (type == FYI && cifsFYI & CIFS_INFO) {			\
+		pr_debug_ratelimited("%s: "				\
+			    fmt, __FILE__, ##__VA_ARGS__);		\
 	} else if (type == VFS) {					\
 		cifs_vfs_err(fmt, ##__VA_ARGS__);			\
 	} else if (type == NOISY && type != 0) {			\
-		pr_debug(fmt, ##__VA_ARGS__);				\
+		pr_debug_ratelimited(fmt, ##__VA_ARGS__);		\
 	}								\
 } while (0)
 

sources/4.2/cifs_spnego.c

@@ -24,10 +24,13 @@
 #include <linux/string.h>
 #include <keys/user-type.h>
 #include <linux/key-type.h>
+#include <linux/keyctl.h>
 #include <linux/inet.h>
 #include "cifsglob.h"
 #include "cifs_spnego.h"
 #include "cifs_debug.h"
+#include "cifsproto.h"
+static const struct cred *spnego_cred;
 
 /* create a new cifs key */
 static int
@@ -102,6 +105,7 @@ cifs_get_spnego_key(struct cifs_ses *sesInfo)
 	size_t desc_len;
 	struct key *spnego_key;
 	const char *hostname = server->hostname;
+	const struct cred *saved_cred;
 
 	/* length of fields (with semicolons): ver=0xyz ip4=ipaddress
 	   host=hostname sec=mechanism uid=0xFF user=username */
@@ -163,7 +167,9 @@ cifs_get_spnego_key(struct cifs_ses *sesInfo)
 	sprintf(dp, ";pid=0x%x", current->pid);
 
 	cifs_dbg(FYI, "key description = %s\n", description);
+	saved_cred = override_creds(spnego_cred);
 	spnego_key = request_key(&cifs_spnego_key_type, description, "");
+	revert_creds(saved_cred);
 
 #ifdef CONFIG_CIFS_DEBUG2
 	if (cifsFYI && !IS_ERR(spnego_key)) {
@@ -177,3 +183,64 @@ out:
 	kfree(description);
 	return spnego_key;
 }
+
+int
+init_cifs_spnego(void)
+{
+	struct cred *cred;
+	struct key *keyring;
+	int ret;
+
+	cifs_dbg(FYI, "Registering the %s key type\n",
+		 cifs_spnego_key_type.name);
+
+	/*
+	 * Create an override credential set with special thread keyring for
+	 * spnego upcalls.
+	 */
+
+	cred = prepare_kernel_cred(NULL);
+	if (!cred)
+		return -ENOMEM;
+
+	keyring = keyring_alloc(".cifs_spnego",
+				GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
+				(KEY_POS_ALL & ~KEY_POS_SETATTR) |
+				KEY_USR_VIEW | KEY_USR_READ,
+				KEY_ALLOC_NOT_IN_QUOTA, NULL);
+	if (IS_ERR(keyring)) {
+		ret = PTR_ERR(keyring);
+		goto failed_put_cred;
+	}
+
+	ret = register_key_type(&cifs_spnego_key_type);
+	if (ret < 0)
+		goto failed_put_key;
+
+	/*
+	 * instruct request_key() to use this special keyring as a cache for
+	 * the results it looks up
+	 */
+	set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
+	cred->thread_keyring = keyring;
+	cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
+	spnego_cred = cred;
+
+	cifs_dbg(FYI, "cifs spnego keyring: %d\n", key_serial(keyring));
+	return 0;
+
+failed_put_key:
+	key_put(keyring);
+failed_put_cred:
+	put_cred(cred);
+	return ret;
+}
+
+void
+exit_cifs_spnego(void)
+{
+	key_revoke(spnego_cred->thread_keyring);
+	unregister_key_type(&cifs_spnego_key_type);
+	put_cred(spnego_cred);
+	cifs_dbg(FYI, "Unregistered %s key type\n", cifs_spnego_key_type.name);
+}

sources/4.2/cifsencrypt.c

@@ -714,7 +714,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
 
 	ses->auth_key.response = kmalloc(baselen + tilen, GFP_KERNEL);
 	if (!ses->auth_key.response) {
-		rc = ENOMEM;
+		rc = -ENOMEM;
 		ses->auth_key.len = 0;
 		goto setup_ntlmv2_rsp_ret;
 	}

sources/4.2/cifsfs.c

@@ -1241,7 +1241,7 @@ init_cifs(void)
 		goto out_destroy_mids;
 
 #ifdef CONFIG_CIFS_UPCALL
-	rc = register_key_type(&cifs_spnego_key_type);
+	rc = init_cifs_spnego();
 	if (rc)
 		goto out_destroy_request_bufs;
 #endif /* CONFIG_CIFS_UPCALL */
@@ -1264,7 +1264,7 @@ out_init_cifs_idmap:
 out_register_key_type:
 #endif
 #ifdef CONFIG_CIFS_UPCALL
-	unregister_key_type(&cifs_spnego_key_type);
+	exit_cifs_spnego();
 out_destroy_request_bufs:
 #endif
 	cifs_destroy_request_bufs();

sources/4.2/cifsfs.h

@@ -31,19 +31,15 @@
  * so that it will fit. We use hash_64 to convert the value to 31 bits, and
  * then add 1, to ensure that we don't end up with a 0 as the value.
  */
-#if BITS_PER_LONG == 64
 static inline ino_t
 cifs_uniqueid_to_ino_t(u64 fileid)
 {
+	if ((sizeof(ino_t)) < (sizeof(u64)))
+		return (ino_t)hash_64(fileid, (sizeof(ino_t) * 8) - 1) + 1;
+
 	return (ino_t)fileid;
+
 }
-#else
-static inline ino_t
-cifs_uniqueid_to_ino_t(u64 fileid)
-{
-	return (ino_t)hash_64(fileid, (sizeof(ino_t) * 8) - 1) + 1;
-}
-#endif
 
 extern struct file_system_type cifs_fs_type;
 extern const struct address_space_operations cifs_addr_ops;

sources/4.2/cifsproto.h

@@ -60,6 +60,8 @@ do {								\
 } while (0)
 extern int init_cifs_idmap(void);
 extern void exit_cifs_idmap(void);
+extern int init_cifs_spnego(void);
+extern void exit_cifs_spnego(void);
 extern char *build_path_from_dentry(struct dentry *);
 extern char *cifs_build_path_to_root(struct smb_vol *vol,
 				     struct cifs_sb_info *cifs_sb,

sources/4.2/cifssmb.c

@@ -1401,11 +1401,10 @@ openRetry:
  * current bigbuf.
  */
 static int
-cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+discard_remaining_data(struct TCP_Server_Info *server)
 {
 	unsigned int rfclen = get_rfc1002_length(server->smallbuf);
 	int remaining = rfclen + 4 - server->total_read;
-	struct cifs_readdata *rdata = mid->callback_data;
 
 	while (remaining > 0) {
 		int length;
@@ -1419,10 +1418,20 @@ cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 		remaining -= length;
 	}
 
-	dequeue_mid(mid, rdata->result);
 	return 0;
 }
 
+static int
+cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
+{
+	int length;
+	struct cifs_readdata *rdata = mid->callback_data;
+
+	length = discard_remaining_data(server);
+	dequeue_mid(mid, rdata->result);
+	return length;
+}
+
 int
 cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 {
@@ -1451,6 +1460,12 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 		return length;
 	server->total_read += length;
 
+	if (server->ops->is_status_pending &&
+	    server->ops->is_status_pending(buf, server, 0)) {
+		discard_remaining_data(server);
+		return -1;
+	}
+
 	/* Was the SMB read successful? */
 	rdata->result = server->ops->map_error(buf, false);
 	if (rdata->result != 0) {

sources/4.2/connect.c

@@ -363,7 +363,6 @@ cifs_reconnect(struct TCP_Server_Info *server)
 	server->session_key.response = NULL;
 	server->session_key.len = 0;
 	server->lstrp = jiffies;
-	mutex_unlock(&server->srv_mutex);
 
 	/* mark submitted MIDs for retry and issue callback */
 	INIT_LIST_HEAD(&retry_list);
@@ -376,6 +375,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
 		list_move(&mid_entry->qhead, &retry_list);
 	}
 	spin_unlock(&GlobalMid_Lock);
+	mutex_unlock(&server->srv_mutex);
 
 	cifs_dbg(FYI, "%s: issuing mid callbacks\n", __func__);
 	list_for_each_safe(tmp, tmp2, &retry_list) {

sources/4.2/inode.c

@@ -1836,11 +1836,11 @@ cifs_invalidate_mapping(struct inode *inode)
  * @word: long word containing the bit lock
  */
 static int
-cifs_wait_bit_killable(struct wait_bit_key *key)
+cifs_wait_bit_killable(struct wait_bit_key *key, int mode)
 {
-	if (fatal_signal_pending(current))
-		return -ERESTARTSYS;
 	freezable_schedule_unsafe();
+	if (signal_pending_state(mode, current))
+		return -ERESTARTSYS;
 	return 0;
 }
 

sources/4.2/readdir.c

@@ -847,6 +847,7 @@ int cifs_readdir(struct file *file, struct dir_context *ctx)
 		 * if buggy server returns . and .. late do we want to
 		 * check for that here?
 		 */
+		*tmp_buf = 0;
 		rc = cifs_filldir(current_entry, file, ctx,
 				  tmp_buf, max_len);
 		if (rc) {

sources/4.2/sess.c

@@ -400,19 +400,27 @@ int build_ntlmssp_auth_blob(unsigned char *pbuffer,
 	sec_blob->LmChallengeResponse.MaximumLength = 0;
 
 	sec_blob->NtChallengeResponse.BufferOffset = cpu_to_le32(tmp - pbuffer);
-	rc = setup_ntlmv2_rsp(ses, nls_cp);
-	if (rc) {
-		cifs_dbg(VFS, "Error %d during NTLMSSP authentication\n", rc);
-		goto setup_ntlmv2_ret;
+	if (ses->user_name != NULL) {
+		rc = setup_ntlmv2_rsp(ses, nls_cp);
+		if (rc) {
+			cifs_dbg(VFS, "Error %d during NTLMSSP authentication\n", rc);
+			goto setup_ntlmv2_ret;
+		}
+		memcpy(tmp, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+				ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+		tmp += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
+
+		sec_blob->NtChallengeResponse.Length =
+				cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+		sec_blob->NtChallengeResponse.MaximumLength =
+				cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+	} else {
+		/*
+		 * don't send an NT Response for anonymous access
+		 */
+		sec_blob->NtChallengeResponse.Length = 0;
+		sec_blob->NtChallengeResponse.MaximumLength = 0;
 	}
-	memcpy(tmp, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
-			ses->auth_key.len - CIFS_SESS_KEY_SIZE);
-	tmp += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
-
-	sec_blob->NtChallengeResponse.Length =
-			cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
-	sec_blob->NtChallengeResponse.MaximumLength =
-			cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
 
 	if (ses->domainName == NULL) {
 		sec_blob->DomainName.BufferOffset = cpu_to_le32(tmp - pbuffer);
@@ -670,20 +678,24 @@ sess_auth_lanman(struct sess_data *sess_data)
 
 	pSMB->req.hdr.Flags2 &= ~SMBFLG2_UNICODE;
 
-	/* no capabilities flags in old lanman negotiation */
-	pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);
-
-	/* Calculate hash with password and copy into bcc_ptr.
-	 * Encryption Key (stored as in cryptkey) gets used if the
-	 * security mode bit in Negottiate Protocol response states
-	 * to use challenge/response method (i.e. Password bit is 1).
-	 */
-	rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
-			      ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
-			      true : false, lnm_session_key);
-
-	memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
-	bcc_ptr += CIFS_AUTH_RESP_SIZE;
+	if (ses->user_name != NULL) {
+		/* no capabilities flags in old lanman negotiation */
+		pSMB->old_req.PasswordLength = cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+
+		/* Calculate hash with password and copy into bcc_ptr.
+		 * Encryption Key (stored as in cryptkey) gets used if the
+		 * security mode bit in Negottiate Protocol response states
+		 * to use challenge/response method (i.e. Password bit is 1).
+		 */
+		rc = calc_lanman_hash(ses->password, ses->server->cryptkey,
+				      ses->server->sec_mode & SECMODE_PW_ENCRYPT ?
+				      true : false, lnm_session_key);
+
+		memcpy(bcc_ptr, (char *)lnm_session_key, CIFS_AUTH_RESP_SIZE);
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+	} else {
+		pSMB->old_req.PasswordLength = 0;
+	}
 
 	/*
 	 * can not sign if LANMAN negotiated so no need
@@ -769,26 +781,31 @@ sess_auth_ntlm(struct sess_data *sess_data)
 	capabilities = cifs_ssetup_hdr(ses, pSMB);
 
 	pSMB->req_no_secext.Capabilities = cpu_to_le32(capabilities);
-	pSMB->req_no_secext.CaseInsensitivePasswordLength =
-			cpu_to_le16(CIFS_AUTH_RESP_SIZE);
-	pSMB->req_no_secext.CaseSensitivePasswordLength =
-			cpu_to_le16(CIFS_AUTH_RESP_SIZE);
-
-	/* calculate ntlm response and session key */
-	rc = setup_ntlm_response(ses, sess_data->nls_cp);
-	if (rc) {
-		cifs_dbg(VFS, "Error %d during NTLM authentication\n",
-				 rc);
-		goto out;
-	}
+	if (ses->user_name != NULL) {
+		pSMB->req_no_secext.CaseInsensitivePasswordLength =
+				cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+		pSMB->req_no_secext.CaseSensitivePasswordLength =
+				cpu_to_le16(CIFS_AUTH_RESP_SIZE);
+
+		/* calculate ntlm response and session key */
+		rc = setup_ntlm_response(ses, sess_data->nls_cp);
+		if (rc) {
+			cifs_dbg(VFS, "Error %d during NTLM authentication\n",
+					 rc);
+			goto out;
+		}
 
-	/* copy ntlm response */
-	memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
-			CIFS_AUTH_RESP_SIZE);
-	bcc_ptr += CIFS_AUTH_RESP_SIZE;
-	memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
-			CIFS_AUTH_RESP_SIZE);
-	bcc_ptr += CIFS_AUTH_RESP_SIZE;
+		/* copy ntlm response */
+		memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+				CIFS_AUTH_RESP_SIZE);
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+		memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+				CIFS_AUTH_RESP_SIZE);
+		bcc_ptr += CIFS_AUTH_RESP_SIZE;
+	} else {
+		pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
+		pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
+	}
 
 	if (ses->capabilities & CAP_UNICODE) {
 		/* unicode strings must be word aligned */
@@ -878,22 +895,26 @@ sess_auth_ntlmv2(struct sess_data *sess_data)
 	/* LM2 password would be here if we supported it */
 	pSMB->req_no_secext.CaseInsensitivePasswordLength = 0;
 
-	/* calculate nlmv2 response and session key */
-	rc = setup_ntlmv2_rsp(ses, sess_data->nls_cp);
-	if (rc) {
-		cifs_dbg(VFS, "Error %d during NTLMv2 authentication\n", rc);
-		goto out;
-	}
+	if (ses->user_name != NULL) {
+		/* calculate nlmv2 response and session key */
+		rc = setup_ntlmv2_rsp(ses, sess_data->nls_cp);
+		if (rc) {
+			cifs_dbg(VFS, "Error %d during NTLMv2 authentication\n", rc);
+			goto out;
+		}
 
-	memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
-			ses->auth_key.len - CIFS_SESS_KEY_SIZE);
-	bcc_ptr += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
+		memcpy(bcc_ptr, ses->auth_key.response + CIFS_SESS_KEY_SIZE,
+				ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+		bcc_ptr += ses->auth_key.len - CIFS_SESS_KEY_SIZE;
 
-	/* set case sensitive password length after tilen may get
-	 * assigned, tilen is 0 otherwise.
-	 */
-	pSMB->req_no_secext.CaseSensitivePasswordLength =
-		cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+		/* set case sensitive password length after tilen may get
+		 * assigned, tilen is 0 otherwise.
+		 */
+		pSMB->req_no_secext.CaseSensitivePasswordLength =
+			cpu_to_le16(ses->auth_key.len - CIFS_SESS_KEY_SIZE);
+	} else {
+		pSMB->req_no_secext.CaseSensitivePasswordLength = 0;
+	}
 
 	if (ses->capabilities & CAP_UNICODE) {
 		if (sess_data->iov[0].iov_len % 2) {

sources/4.2/smb2glob.h

@@ -44,6 +44,7 @@
 #define SMB2_OP_DELETE 7
 #define SMB2_OP_HARDLINK 8
 #define SMB2_OP_SET_EOF 9
+#define SMB2_OP_RMDIR 10
 
 /* Used when constructing chained read requests. */
 #define CHAINED_REQUEST 1

sources/4.2/smb2inode.c

@@ -81,6 +81,10 @@ smb2_open_op_close(const unsigned int xid, struct cifs_tcon *tcon,
 		 * SMB2_open() call.
 		 */
 		break;
+	case SMB2_OP_RMDIR:
+		tmprc = SMB2_rmdir(xid, tcon, fid.persistent_fid,
+				   fid.volatile_fid);
+		break;
 	case SMB2_OP_RENAME:
 		tmprc = SMB2_rename(xid, tcon, fid.persistent_fid,
 				    fid.volatile_fid, (__le16 *)data);
@@ -192,8 +196,8 @@ smb2_rmdir(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
 	   struct cifs_sb_info *cifs_sb)
 {
 	return smb2_open_op_close(xid, tcon, cifs_sb, name, DELETE, FILE_OPEN,
-				  CREATE_NOT_FILE | CREATE_DELETE_ON_CLOSE,
-				  NULL, SMB2_OP_DELETE);
+				  CREATE_NOT_FILE,
+				  NULL, SMB2_OP_RMDIR);
 }
 
 int

sources/4.2/smb2pdu.c

@@ -1101,21 +1101,25 @@ parse_lease_state(struct TCP_Server_Info *server, struct smb2_create_rsp *rsp,
 {
 	char *data_offset;
 	struct create_context *cc;
-	unsigned int next = 0;
+	unsigned int next;
+	unsigned int remaining;
 	char *name;
 
 	data_offset = (char *)rsp + 4 + le32_to_cpu(rsp->CreateContextsOffset);
+	remaining = le32_to_cpu(rsp->CreateContextsLength);
 	cc = (struct create_context *)data_offset;
-	do {
-		cc = (struct create_context *)((char *)cc + next);
+	while (remaining >= sizeof(struct create_context)) {
 		name = le16_to_cpu(cc->NameOffset) + (char *)cc;
-		if (le16_to_cpu(cc->NameLength) != 4 ||
-		    strncmp(name, "RqLs", 4)) {
-			next = le32_to_cpu(cc->Next);
-			continue;
-		}
-		return server->ops->parse_lease_buf(cc, epoch);
-	} while (next != 0);
+		if (le16_to_cpu(cc->NameLength) == 4 &&
+		    strncmp(name, "RqLs", 4) == 0)
+			return server->ops->parse_lease_buf(cc, epoch);
+
+		next = le32_to_cpu(cc->Next);
+		if (!next)
+			break;
+		remaining -= next;
+		cc = (struct create_context *)((char *)cc + next);
+	}
 
 	return 0;
 }
@@ -2439,6 +2443,22 @@ SMB2_rename(const unsigned int xid, struct cifs_tcon *tcon,
 }
 
 int
+SMB2_rmdir(const unsigned int xid, struct cifs_tcon *tcon,
+		  u64 persistent_fid, u64 volatile_fid)
+{
+	__u8 delete_pending = 1;
+	void *data;
+	unsigned int size;
+
+	data = &delete_pending;
+	size = 1; /* sizeof __u8 */
+
+	return send_set_info(xid, tcon, persistent_fid, volatile_fid,
+			current->tgid, FILE_DISPOSITION_INFORMATION, 1, &data,
+			&size);
+}
+
+int
 SMB2_set_hardlink(const unsigned int xid, struct cifs_tcon *tcon,
 		  u64 persistent_fid, u64 volatile_fid, __le16 *target_file)
 {

sources/4.2/smb2proto.h

@@ -140,6 +140,8 @@ extern int SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
 extern int SMB2_rename(const unsigned int xid, struct cifs_tcon *tcon,
 		       u64 persistent_fid, u64 volatile_fid,
 		       __le16 *target_file);
+extern int SMB2_rmdir(const unsigned int xid, struct cifs_tcon *tcon,
+		      u64 persistent_fid, u64 volatile_fid);
 extern int SMB2_set_hardlink(const unsigned int xid, struct cifs_tcon *tcon,
 			     u64 persistent_fid, u64 volatile_fid,
 			     __le16 *target_file);

sources/4.2/transport.c

@@ -576,14 +576,16 @@ cifs_call_async(struct TCP_Server_Info *server, struct smb_rqst *rqst,
 	cifs_in_send_dec(server);
 	cifs_save_when_sent(mid);
 
-	if (rc < 0)
+	if (rc < 0) {
 		server->sequence_number -= 2;
+		cifs_delete_mid(mid);
+	}
+
 	mutex_unlock(&server->srv_mutex);
 
 	if (rc == 0)
 		return 0;
 
-	cifs_delete_mid(mid);
 	add_credits_and_wake_if(server, credits, optype);
 	return rc;
 }