diff --git a/fs/smb/client/Makefile b/fs/smb/client/Makefile
index 3abd357d6df6..26b6105f04d1 100644
--- a/fs/smb/client/Makefile
+++ b/fs/smb/client/Makefile
@@ -56,4 +56,6 @@ $(obj)/smb2maperror.o: $(obj)/smb2_mapping_table.c
 quiet_cmd_gen_smb2_mapping = GEN     $@
       cmd_gen_smb2_mapping = perl $(src)/gen_smb2_mapping $< $@
 
+obj-$(CONFIG_SMB_KUNIT_TESTS) += smb2maperror_test.o
+
 clean-files	+= smb2_mapping_table.c
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index 427558404aa5..b6e3db993cc6 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -332,10 +332,14 @@ static void cifs_kill_sb(struct super_block *sb)
 
 	/*
 	 * We need to release all dentries for the cached directories
-	 * before we kill the sb.
+	 * and close all deferred file handles before we kill the sb.
 	 */
 	if (cifs_sb->root) {
 		close_all_cached_dirs(cifs_sb);
+		cifs_close_all_deferred_files_sb(cifs_sb);
+
+		/* Wait for all pending oplock breaks to complete */
+		flush_workqueue(cifsoplockd_wq);
 
 		/* finally release root dentry */
 		dput(cifs_sb->root);
@@ -868,7 +872,6 @@ static void cifs_umount_begin(struct super_block *sb)
 	spin_unlock(&tcon->tc_lock);
 	spin_unlock(&cifs_tcp_ses_lock);
 
-	cifs_close_all_deferred_files(tcon);
 	/* cancel_brl_requests(tcon); */ /* BB mark all brl mids as exiting */
 	/* cancel_notify_requests(tcon); */
 	if (tcon->ses && tcon->ses->server) {
diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index 96d6b5325aa3..800a7e418c32 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -261,6 +261,7 @@ void cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode);
 
 void cifs_close_all_deferred_files(struct cifs_tcon *tcon);
 
+void cifs_close_all_deferred_files_sb(struct cifs_sb_info *cifs_sb);
 void cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon,
 					   struct dentry *dentry);
 
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index f3ddcdf406c8..cffcf82c1b69 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -711,8 +711,6 @@ struct cifsFileInfo *cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 	mutex_init(&cfile->fh_mutex);
 	spin_lock_init(&cfile->file_info_lock);
 
-	cifs_sb_active(inode->i_sb);
-
 	/*
 	 * If the server returned a read oplock and we have mandatory brlocks,
 	 * set oplock level to None.
@@ -767,7 +765,6 @@ static void cifsFileInfo_put_final(struct cifsFileInfo *cifs_file)
 	struct inode *inode = d_inode(cifs_file->dentry);
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 	struct cifsLockInfo *li, *tmp;
-	struct super_block *sb = inode->i_sb;
 
 	/*
 	 * Delete any outstanding lock records. We'll lose them when the file
@@ -785,7 +782,6 @@ static void cifsFileInfo_put_final(struct cifsFileInfo *cifs_file)
 
 	cifs_put_tlink(cifs_file->tlink);
 	dput(cifs_file->dentry);
-	cifs_sb_deactive(sb);
 	kfree(cifs_file->symlink_target);
 	kfree(cifs_file);
 }
@@ -3163,12 +3159,6 @@ void cifs_oplock_break(struct work_struct *work)
 	__u64 persistent_fid, volatile_fid;
 	__u16 net_fid;
 
-	/*
-	 * Hold a reference to the superblock to prevent it and its inodes from
-	 * being freed while we are accessing cinode. Otherwise, _cifsFileInfo_put()
-	 * may release the last reference to the sb and trigger inode eviction.
-	 */
-	cifs_sb_active(sb);
 	wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
 			TASK_UNINTERRUPTIBLE);
 
@@ -3253,7 +3243,6 @@ oplock_break_ack:
 	cifs_put_tlink(tlink);
 out:
 	cifs_done_oplock_break(cinode);
-	cifs_sb_deactive(sb);
 }
 
 static int cifs_swap_activate(struct swap_info_struct *sis,
diff --git a/fs/smb/client/misc.c b/fs/smb/client/misc.c
index bc24c92b8b95..2aff1cab6c31 100644
--- a/fs/smb/client/misc.c
+++ b/fs/smb/client/misc.c
@@ -28,6 +28,11 @@
 #include "fs_context.h"
 #include "cached_dir.h"
 
+struct tcon_list {
+	struct list_head entry;
+	struct cifs_tcon *tcon;
+};
+
 /* The xid serves as a useful identifier for each incoming vfs request,
    in a similar way to the mid which is useful to track each sent smb,
    and CurrentXid can also provide a running counter (although it
@@ -554,6 +559,43 @@ cifs_close_all_deferred_files(struct cifs_tcon *tcon)
 	}
 }
 
+void cifs_close_all_deferred_files_sb(struct cifs_sb_info *cifs_sb)
+{
+	struct rb_root *root = &cifs_sb->tlink_tree;
+	struct rb_node *node;
+	struct cifs_tcon *tcon;
+	struct tcon_link *tlink;
+	struct tcon_list *tmp_list, *q;
+	LIST_HEAD(tcon_head);
+
+	spin_lock(&cifs_sb->tlink_tree_lock);
+	for (node = rb_first(root); node; node = rb_next(node)) {
+		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
+		tcon = tlink_tcon(tlink);
+		if (IS_ERR(tcon))
+			continue;
+		tmp_list = kmalloc_obj(struct tcon_list, GFP_ATOMIC);
+		if (tmp_list == NULL)
+			break;
+		tmp_list->tcon = tcon;
+		/* Take a reference on tcon to prevent it from being freed */
+		spin_lock(&tcon->tc_lock);
+		++tcon->tc_count;
+		trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count,
+				    netfs_trace_tcon_ref_get_close_defer_files);
+		spin_unlock(&tcon->tc_lock);
+		list_add_tail(&tmp_list->entry, &tcon_head);
+	}
+	spin_unlock(&cifs_sb->tlink_tree_lock);
+
+	list_for_each_entry_safe(tmp_list, q, &tcon_head, entry) {
+		cifs_close_all_deferred_files(tmp_list->tcon);
+		list_del(&tmp_list->entry);
+		cifs_put_tcon(tmp_list->tcon, netfs_trace_tcon_ref_put_close_defer_files);
+		kfree(tmp_list);
+	}
+}
+
 void cifs_close_deferred_file_under_dentry(struct cifs_tcon *tcon,
 					   struct dentry *dentry)
 {
diff --git a/fs/smb/client/smb1encrypt.c b/fs/smb/client/smb1encrypt.c
index 0dbbce2431ff..bf10fdeeedca 100644
--- a/fs/smb/client/smb1encrypt.c
+++ b/fs/smb/client/smb1encrypt.c
@@ -11,6 +11,7 @@
 
 #include <linux/fips.h>
 #include <crypto/md5.h>
+#include <crypto/utils.h>
 #include "cifsproto.h"
 #include "smb1proto.h"
 #include "cifs_debug.h"
@@ -131,7 +132,7 @@ int cifs_verify_signature(struct smb_rqst *rqst,
 /*	cifs_dump_mem("what we think it should be: ",
 		      what_we_think_sig_should_be, 16); */
 
-	if (memcmp(server_response_sig, what_we_think_sig_should_be, 8))
+	if (crypto_memneq(server_response_sig, what_we_think_sig_should_be, 8))
 		return -EACCES;
 	else
 		return 0;
diff --git a/fs/smb/client/smb2glob.h b/fs/smb/client/smb2glob.h
index e56e4d402f13..19da74b1edab 100644
--- a/fs/smb/client/smb2glob.h
+++ b/fs/smb/client/smb2glob.h
@@ -46,4 +46,16 @@ enum smb2_compound_ops {
 #define END_OF_CHAIN 4
 #define RELATED_REQUEST 8
 
+/*
+ *****************************************************************
+ * Struct definitions go here
+ *****************************************************************
+ */
+
+struct status_to_posix_error {
+	__u32 smb2_status;
+	int posix_error;
+	char *status_string;
+};
+
 #endif	/* _SMB2_GLOB_H */
diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 195a38fd61e8..5280c5c869ad 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -325,7 +325,7 @@ replay_again:
 							  cfile->fid.volatile_fid,
 							  SMB_FIND_FILE_POSIX_INFO,
 							  SMB2_O_INFO_FILE, 0,
-							  sizeof(struct smb311_posix_qinfo *) +
+							  sizeof(struct smb311_posix_qinfo) +
 							  (PATH_MAX * 2) +
 							  (sizeof(struct smb_sid) * 2), 0, NULL);
 			} else {
@@ -335,7 +335,7 @@ replay_again:
 							  COMPOUND_FID,
 							  SMB_FIND_FILE_POSIX_INFO,
 							  SMB2_O_INFO_FILE, 0,
-							  sizeof(struct smb311_posix_qinfo *) +
+							  sizeof(struct smb311_posix_qinfo) +
 							  (PATH_MAX * 2) +
 							  (sizeof(struct smb_sid) * 2), 0, NULL);
 			}
@@ -1216,6 +1216,7 @@ again:
 	memset(resp_buftype, 0, sizeof(resp_buftype));
 	memset(rsp_iov, 0, sizeof(rsp_iov));
 
+	memset(open_iov, 0, sizeof(open_iov));
 	rqst[0].rq_iov = open_iov;
 	rqst[0].rq_nvec = ARRAY_SIZE(open_iov);
 
@@ -1240,14 +1241,15 @@ again:
 	creq = rqst[0].rq_iov[0].iov_base;
 	creq->ShareAccess = FILE_SHARE_DELETE_LE;
 
+	memset(&close_iov, 0, sizeof(close_iov));
 	rqst[1].rq_iov = &close_iov;
 	rqst[1].rq_nvec = 1;
 
 	rc = SMB2_close_init(tcon, server, &rqst[1],
 			     COMPOUND_FID, COMPOUND_FID, false);
-	smb2_set_related(&rqst[1]);
 	if (rc)
 		goto err_free;
+	smb2_set_related(&rqst[1]);
 
 	if (retries) {
 		/* Back-off before retry */
diff --git a/fs/smb/client/smb2maperror.c b/fs/smb/client/smb2maperror.c
index cd036365201f..f4cff44e2796 100644
--- a/fs/smb/client/smb2maperror.c
+++ b/fs/smb/client/smb2maperror.c
@@ -8,7 +8,6 @@
  *
  */
 #include <linux/errno.h>
-#include "cifsglob.h"
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "smb2proto.h"
@@ -16,12 +15,6 @@
 #include "../common/smb2status.h"
 #include "trace.h"
 
-struct status_to_posix_error {
-	__u32 smb2_status;
-	int posix_error;
-	char *status_string;
-};
-
 static const struct status_to_posix_error smb2_error_map_table[] = {
 /*
  * Automatically generated by the `gen_smb2_mapping` script,
@@ -115,10 +108,19 @@ int __init smb2_init_maperror(void)
 	return 0;
 }
 
-#define SMB_CLIENT_KUNIT_AVAILABLE \
-	((IS_MODULE(CONFIG_CIFS) && IS_ENABLED(CONFIG_KUNIT)) || \
-	 (IS_BUILTIN(CONFIG_CIFS) && IS_BUILTIN(CONFIG_KUNIT)))
+#if IS_ENABLED(CONFIG_SMB_KUNIT_TESTS)
+/* Previous prototype for eliminating the build warning. */
+const struct status_to_posix_error *smb2_get_err_map_test(__u32 smb2_status);
 
-#if SMB_CLIENT_KUNIT_AVAILABLE && IS_ENABLED(CONFIG_SMB_KUNIT_TESTS)
-#include "smb2maperror_test.c"
-#endif /* CONFIG_SMB_KUNIT_TESTS */
+const struct status_to_posix_error *smb2_get_err_map_test(__u32 smb2_status)
+{
+	return smb2_get_err_map(smb2_status);
+}
+EXPORT_SYMBOL_GPL(smb2_get_err_map_test);
+
+const struct status_to_posix_error *smb2_error_map_table_test = smb2_error_map_table;
+EXPORT_SYMBOL_GPL(smb2_error_map_table_test);
+
+unsigned int smb2_error_map_num = ARRAY_SIZE(smb2_error_map_table);
+EXPORT_SYMBOL_GPL(smb2_error_map_num);
+#endif
diff --git a/fs/smb/client/smb2maperror_test.c b/fs/smb/client/smb2maperror_test.c
index 38ea6b846a99..8c47dea7a2c1 100644
--- a/fs/smb/client/smb2maperror_test.c
+++ b/fs/smb/client/smb2maperror_test.c
@@ -9,13 +9,18 @@
  */
 
 #include <kunit/test.h>
+#include "smb2glob.h"
+
+const struct status_to_posix_error *smb2_get_err_map_test(__u32 smb2_status);
+extern const struct status_to_posix_error *smb2_error_map_table_test;
+extern unsigned int smb2_error_map_num;
 
 static void
 test_cmp_map(struct kunit *test, const struct status_to_posix_error *expect)
 {
 	const struct status_to_posix_error *result;
 
-	result = smb2_get_err_map(expect->smb2_status);
+	result = smb2_get_err_map_test(expect->smb2_status);
 	KUNIT_EXPECT_PTR_NE(test, NULL, result);
 	KUNIT_EXPECT_EQ(test, expect->smb2_status, result->smb2_status);
 	KUNIT_EXPECT_EQ(test, expect->posix_error, result->posix_error);
@@ -26,8 +31,8 @@ static void maperror_test_check_search(struct kunit *test)
 {
 	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(smb2_error_map_table); i++)
-		test_cmp_map(test, &smb2_error_map_table[i]);
+	for (i = 0; i < smb2_error_map_num; i++)
+		test_cmp_map(test, &smb2_error_map_table_test[i]);
 }
 
 static struct kunit_case maperror_test_cases[] = {
@@ -43,3 +48,4 @@ static struct kunit_suite maperror_suite = {
 kunit_test_suite(maperror_suite);
 
 MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KUnit tests of SMB2 maperror");
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 04e361ed2356..c43ca74e8704 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -3989,24 +3989,6 @@ int SMB2_query_info(const unsigned int xid, struct cifs_tcon *tcon,
 			  NULL);
 }
 
-#if 0
-/* currently unused, as now we are doing compounding instead (see smb311_posix_query_path_info) */
-int
-SMB311_posix_query_info(const unsigned int xid, struct cifs_tcon *tcon,
-			u64 persistent_fid, u64 volatile_fid,
-			struct smb311_posix_qinfo *data, u32 *plen)
-{
-	size_t output_len = sizeof(struct smb311_posix_qinfo *) +
-			(sizeof(struct smb_sid) * 2) + (PATH_MAX * 2);
-	*plen = 0;
-
-	return query_info(xid, tcon, persistent_fid, volatile_fid,
-			  SMB_FIND_FILE_POSIX_INFO, SMB2_O_INFO_FILE, 0,
-			  output_len, sizeof(struct smb311_posix_qinfo), (void **)&data, plen);
-	/* Note caller must free "data" (passed in above). It may be allocated in query_info call */
-}
-#endif
-
 int
 SMB2_query_acl(const unsigned int xid, struct cifs_tcon *tcon,
 	       u64 persistent_fid, u64 volatile_fid,
diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h
index 78bb99f29d38..30d70097fe2f 100644
--- a/fs/smb/client/smb2pdu.h
+++ b/fs/smb/client/smb2pdu.h
@@ -224,7 +224,7 @@ struct smb2_file_reparse_point_info {
 	__le32 Tag;
 } __packed;
 
-/* See MS-FSCC 2.4.21 */
+/* See MS-FSCC 2.4.26 */
 struct smb2_file_id_information {
 	__le64	VolumeSerialNumber;
 	__u64  PersistentFileId; /* opaque endianness */
@@ -251,7 +251,10 @@ struct smb2_file_id_extd_directory_info {
 
 extern char smb2_padding[7];
 
-/* equivalent of the contents of SMB3.1.1 POSIX open context response */
+/*
+ * See POSIX-SMB2 2.2.14.2.16
+ * Link: https://gitlab.com/samba-team/smb3-posix-spec/-/blob/master/smb3_posix_extensions.md
+ */
 struct create_posix_rsp {
 	u32 nlink;
 	u32 reparse_tag;
diff --git a/fs/smb/client/smb2proto.h b/fs/smb/client/smb2proto.h
index 881e42cf66ce..230bb1e9f4e1 100644
--- a/fs/smb/client/smb2proto.h
+++ b/fs/smb/client/smb2proto.h
@@ -167,9 +167,6 @@ int SMB2_flush_init(const unsigned int xid, struct smb_rqst *rqst,
 		    struct cifs_tcon *tcon, struct TCP_Server_Info *server,
 		    u64 persistent_fid, u64 volatile_fid);
 void SMB2_flush_free(struct smb_rqst *rqst);
-int SMB311_posix_query_info(const unsigned int xid, struct cifs_tcon *tcon,
-			    u64 persistent_fid, u64 volatile_fid,
-			    struct smb311_posix_qinfo *data, u32 *plen);
 int SMB2_query_info(const unsigned int xid, struct cifs_tcon *tcon,
 		    u64 persistent_fid, u64 volatile_fid,
 		    struct smb2_file_all_info *data);
diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c
index 8b9000a83181..81be2b226e26 100644
--- a/fs/smb/client/smb2transport.c
+++ b/fs/smb/client/smb2transport.c
@@ -20,6 +20,7 @@
 #include <linux/highmem.h>
 #include <crypto/aead.h>
 #include <crypto/sha2.h>
+#include <crypto/utils.h>
 #include "cifsglob.h"
 #include "cifsproto.h"
 #include "smb2proto.h"
@@ -617,7 +618,8 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 	if (rc)
 		return rc;
 
-	if (memcmp(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE)) {
+	if (crypto_memneq(server_response_sig, shdr->Signature,
+			  SMB2_SIGNATURE_SIZE)) {
 		cifs_dbg(VFS, "sign fail cmd 0x%x message id 0x%llx\n",
 			shdr->Command, shdr->MessageId);
 		return -EACCES;
diff --git a/fs/smb/client/trace.h b/fs/smb/client/trace.h
index 9228f95cae2b..acfbb63086ea 100644
--- a/fs/smb/client/trace.h
+++ b/fs/smb/client/trace.h
@@ -176,6 +176,7 @@
 	EM(netfs_trace_tcon_ref_get_cached_laundromat,	"GET Ch-Lau") \
 	EM(netfs_trace_tcon_ref_get_cached_lease_break,	"GET Ch-Lea") \
 	EM(netfs_trace_tcon_ref_get_cancelled_close,	"GET Cn-Cls") \
+	EM(netfs_trace_tcon_ref_get_close_defer_files,	"GET Cl-Def") \
 	EM(netfs_trace_tcon_ref_get_dfs_refer,		"GET DfsRef") \
 	EM(netfs_trace_tcon_ref_get_find,		"GET Find  ") \
 	EM(netfs_trace_tcon_ref_get_find_sess_tcon,	"GET FndSes") \
@@ -187,6 +188,7 @@
 	EM(netfs_trace_tcon_ref_put_cancelled_close,	"PUT Cn-Cls") \
 	EM(netfs_trace_tcon_ref_put_cancelled_close_fid, "PUT Cn-Fid") \
 	EM(netfs_trace_tcon_ref_put_cancelled_mid,	"PUT Cn-Mid") \
+	EM(netfs_trace_tcon_ref_put_close_defer_files,	"PUT Cl-Def") \
 	EM(netfs_trace_tcon_ref_put_mnt_ctx,		"PUT MntCtx") \
 	EM(netfs_trace_tcon_ref_put_dfs_refer,		"PUT DfsRfr") \
 	EM(netfs_trace_tcon_ref_put_reconnect_server,	"PUT Reconn") \
diff --git a/fs/smb/server/smb2pdu.h b/fs/smb/server/smb2pdu.h
index 257c6d26df26..8b6eafb70dca 100644
--- a/fs/smb/server/smb2pdu.h
+++ b/fs/smb/server/smb2pdu.h
@@ -83,7 +83,10 @@ struct create_durable_rsp {
 	} Data;
 } __packed;
 
-/* equivalent of the contents of SMB3.1.1 POSIX open context response */
+/*
+ * See POSIX-SMB2 2.2.14.2.16
+ * Link: https://gitlab.com/samba-team/smb3-posix-spec/-/blob/master/smb3_posix_extensions.md
+ */
 struct create_posix_rsp {
 	struct create_context_hdr ccontext;
 	__u8    Name[16];