10 CIFS/SMB3 changesets including some important multichannel fixes, as well as support for handle leases (deferred close) and shutdown support

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Merge tag '5.13-rc-smb3-part2' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs updates from Steve French:
 "Ten CIFS/SMB3 changes - including two marked for stable - including
  some important multichannel fixes, as well as support for handle
  leases (deferred close) and shutdown support:

   - some important multichannel fixes

   - support for handle leases (deferred close)

   - shutdown support (which is also helpful since it enables multiple
     xfstests)

   - enable negotiating stronger encryption by default (GCM256)

   - improve wireshark debugging by allowing more options for root to
     dump decryption keys

  SambaXP and the SMB3 Plugfest test event are going on now so I am
  expecting more patches over the next few days due to extra testing
  (including more multichannel fixes)"

* tag '5.13-rc-smb3-part2' of git://git.samba.org/sfrench/cifs-2.6:
  fs/cifs: Fix resource leak
  Cifs: Fix kernel oops caused by deferred close for files.
  cifs: fix regression when mounting shares with prefix paths
  cifs: use echo_interval even when connection not ready.
  cifs: detect dead connections only when echoes are enabled.
  smb3.1.1: allow dumping keys for multiuser mounts
  smb3.1.1: allow dumping GCM256 keys to improve debugging of encrypted shares
  cifs: add shutdown support
  cifs: Deferred close for files
  smb3.1.1: enable negotiating stronger encryption by default

fs/cifs/cifs_fs_sb.h

@@ -55,6 +55,7 @@
 #define CIFS_MOUNT_MODE_FROM_SID 0x10000000 /* retrieve mode from special ACE */
 #define CIFS_MOUNT_RO_CACHE	0x20000000  /* assumes share will not change */
 #define CIFS_MOUNT_RW_CACHE	0x40000000  /* assumes only client accessing */
+#define CIFS_MOUNT_SHUTDOWN	0x80000000
 
 struct cifs_sb_info {
 	struct rb_root tlink_tree;

fs/cifs/cifs_ioctl.h

@@ -57,6 +57,12 @@ struct smb_query_info {
 	/* char buffer[]; */
 } __packed;
 
+/*
+ * Dumping the commonly used 16 byte (e.g. CCM and GCM128) keys still supported
+ * for backlevel compatibility, but is not sufficient for dumping the less
+ * frequently used GCM256 (32 byte) keys (see the newer "CIFS_DUMP_FULL_KEY"
+ * ioctl for dumping decryption info for GCM256 mounts)
+ */
 struct smb3_key_debug_info {
 	__u64	Suid;
 	__u16	cipher_type;
@@ -65,6 +71,18 @@ struct smb3_key_debug_info {
 	__u8	smb3decryptionkey[SMB3_SIGN_KEY_SIZE];
 } __packed;
 
+/*
+ * Dump full key (32 byte encrypt/decrypt keys instead of 16 bytes)
+ * is needed if GCM256 (stronger encryption) negotiated
+ */
+struct smb3_full_key_debug_info {
+	__u64	Suid;
+	__u16	cipher_type;
+	__u8	auth_key[16]; /* SMB2_NTLMV2_SESSKEY_SIZE */
+	__u8	smb3encryptionkey[32]; /* SMB3_ENC_DEC_KEY_SIZE */
+	__u8	smb3decryptionkey[32]; /* SMB3_ENC_DEC_KEY_SIZE */
+} __packed;
+
 struct smb3_notify {
 	__u32	completion_filter;
 	bool	watch_tree;
@@ -78,3 +96,20 @@ struct smb3_notify {
 #define CIFS_QUERY_INFO _IOWR(CIFS_IOCTL_MAGIC, 7, struct smb_query_info)
 #define CIFS_DUMP_KEY _IOWR(CIFS_IOCTL_MAGIC, 8, struct smb3_key_debug_info)
 #define CIFS_IOC_NOTIFY _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)
+#define CIFS_DUMP_FULL_KEY _IOWR(CIFS_IOCTL_MAGIC, 10, struct smb3_full_key_debug_info)
+#define CIFS_IOC_SHUTDOWN _IOR ('X', 125, __u32)
+
+/*
+ * Flags for going down operation
+ */
+#define CIFS_GOING_FLAGS_DEFAULT                0x0     /* going down */
+#define CIFS_GOING_FLAGS_LOGFLUSH               0x1     /* flush log but not data */
+#define CIFS_GOING_FLAGS_NOLOGFLUSH             0x2     /* don't flush log nor data */
+
+static inline bool cifs_forced_shutdown(struct cifs_sb_info *sbi)
+{
+	if (CIFS_MOUNT_SHUTDOWN & sbi->mnt_cifs_flags)
+		return true;
+	else
+		return false;
+}

fs/cifs/cifsfs.c

@@ -75,7 +75,7 @@ bool enable_oplocks = true;
 bool linuxExtEnabled = true;
 bool lookupCacheEnabled = true;
 bool disable_legacy_dialects; /* false by default */
-bool enable_gcm_256;  /* false by default, change when more servers support it */
+bool enable_gcm_256 = true;
 bool require_gcm_256; /* false by default */
 unsigned int global_secflags = CIFSSEC_DEF;
 /* unsigned int ntlmv2_support = 0; */
@@ -133,6 +133,7 @@ struct workqueue_struct	*cifsiod_wq;
 struct workqueue_struct	*decrypt_wq;
 struct workqueue_struct	*fileinfo_put_wq;
 struct workqueue_struct	*cifsoplockd_wq;
+struct workqueue_struct *deferredclose_wq;
 __u32 cifs_lock_secret;
 
 /*
@@ -390,6 +391,8 @@ cifs_alloc_inode(struct super_block *sb)
 	/* cifs_inode->vfs_inode.i_flags = S_NOATIME | S_NOCMTIME; */
 	INIT_LIST_HEAD(&cifs_inode->openFileList);
 	INIT_LIST_HEAD(&cifs_inode->llist);
+	INIT_LIST_HEAD(&cifs_inode->deferred_closes);
+	spin_lock_init(&cifs_inode->deferred_lock);
 	return &cifs_inode->vfs_inode;
 }
 
@@ -860,13 +863,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
 		goto out;
 	}
 
-	/* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */
+	rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL);
-	kfree(cifs_sb->ctx->UNC);
-	cifs_sb->ctx->UNC = NULL;
-	kfree(cifs_sb->ctx->prepath);
-	cifs_sb->ctx->prepath = NULL;
-
-	rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
 	if (rc) {
 		root = ERR_PTR(rc);
 		goto out;
@@ -1637,9 +1634,16 @@ init_cifs(void)
 		goto out_destroy_fileinfo_put_wq;
 	}
 
+	deferredclose_wq = alloc_workqueue("deferredclose",
+					   WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
+	if (!deferredclose_wq) {
+		rc = -ENOMEM;
+		goto out_destroy_cifsoplockd_wq;
+	}
+
 	rc = cifs_fscache_register();
 	if (rc)
-		goto out_destroy_cifsoplockd_wq;
+		goto out_destroy_deferredclose_wq;
 
 	rc = cifs_init_inodecache();
 	if (rc)
@@ -1707,6 +1711,8 @@ out_destroy_inodecache:
 	cifs_destroy_inodecache();
 out_unreg_fscache:
 	cifs_fscache_unregister();
+out_destroy_deferredclose_wq:
+	destroy_workqueue(deferredclose_wq);
 out_destroy_cifsoplockd_wq:
 	destroy_workqueue(cifsoplockd_wq);
 out_destroy_fileinfo_put_wq:
@@ -1741,6 +1747,7 @@ exit_cifs(void)
 	cifs_destroy_mids();
 	cifs_destroy_inodecache();
 	cifs_fscache_unregister();
+	destroy_workqueue(deferredclose_wq);
 	destroy_workqueue(cifsoplockd_wq);
 	destroy_workqueue(decrypt_wq);
 	destroy_workqueue(fileinfo_put_wq);

fs/cifs/cifsglob.h

@@ -1154,6 +1154,14 @@ struct cifs_pending_open {
 	__u32 oplock;
 };
 
+struct cifs_deferred_close {
+	struct list_head dlist;
+	struct tcon_link *tlink;
+	__u16  netfid;
+	__u64  persistent_fid;
+	__u64  volatile_fid;
+};
+
 /*
  * This info hangs off the cifsFileInfo structure, pointed to by llist.
  * This is used to track byte stream locks on the file
@@ -1248,6 +1256,9 @@ struct cifsFileInfo {
 	struct cifs_search_info srch_inf;
 	struct work_struct oplock_break; /* work for oplock breaks */
 	struct work_struct put; /* work for the final part of _put */
+	struct delayed_work deferred;
+	bool oplock_break_received; /* Flag to indicate oplock break */
+	bool deferred_scheduled;
 };
 
 struct cifs_io_parms {
@@ -1392,6 +1403,7 @@ struct cifsInodeInfo {
 #define CIFS_INO_DELETE_PENDING		  (3) /* delete pending on server */
 #define CIFS_INO_INVALID_MAPPING	  (4) /* pagecache is invalid */
 #define CIFS_INO_LOCK			  (5) /* lock bit for synchronization */
+#define CIFS_INO_MODIFIED_ATTR            (6) /* Indicate change in mtime/ctime */
 	unsigned long flags;
 	spinlock_t writers_lock;
 	unsigned int writers;		/* Number of writers on this inode */
@@ -1404,6 +1416,8 @@ struct cifsInodeInfo {
 	struct fscache_cookie *fscache;
 #endif
 	struct inode vfs_inode;
+	struct list_head deferred_closes; /* list of deferred closes */
+	spinlock_t deferred_lock; /* protection on deferred list */
 };
 
 static inline struct cifsInodeInfo *
@@ -1871,11 +1885,14 @@ extern bool disable_legacy_dialects;  /* forbid vers=1.0 and vers=2.0 mounts */
 
 void cifs_oplock_break(struct work_struct *work);
 void cifs_queue_oplock_break(struct cifsFileInfo *cfile);
+void smb2_deferred_work_close(struct work_struct *work);
 
+extern const struct slow_work_ops cifs_oplock_break_ops;
 extern struct workqueue_struct *cifsiod_wq;
 extern struct workqueue_struct *decrypt_wq;
 extern struct workqueue_struct *fileinfo_put_wq;
 extern struct workqueue_struct *cifsoplockd_wq;
+extern struct workqueue_struct *deferredclose_wq;
 extern __u32 cifs_lock_secret;
 
 extern mempool_t *cifs_mid_poolp;

fs/cifs/cifsproto.h

@@ -267,6 +267,19 @@ extern void cifs_add_pending_open_locked(struct cifs_fid *fid,
 					 struct tcon_link *tlink,
 					 struct cifs_pending_open *open);
 extern void cifs_del_pending_open(struct cifs_pending_open *open);
+
+extern bool cifs_is_deferred_close(struct cifsFileInfo *cfile,
+				struct cifs_deferred_close **dclose);
+
+extern void cifs_add_deferred_close(struct cifsFileInfo *cfile,
+				struct cifs_deferred_close *dclose);
+
+extern void cifs_del_deferred_close(struct cifsFileInfo *cfile);
+
+extern void cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode);
+
+extern void cifs_close_all_deferred_files(struct cifs_tcon *cifs_tcon);
+
 extern struct TCP_Server_Info *cifs_get_tcp_session(struct smb3_fs_context *ctx);
 extern void cifs_put_tcp_session(struct TCP_Server_Info *server,
 				 int from_reconnect);

fs/cifs/connect.c

@@ -392,16 +392,6 @@ cifs_echo_request(struct work_struct *work)
 	int rc;
 	struct TCP_Server_Info *server = container_of(work,
 					struct TCP_Server_Info, echo.work);
-	unsigned long echo_interval;
-
-	/*
-	 * If we need to renegotiate, set echo interval to zero to
-	 * immediately call echo service where we can renegotiate.
-	 */
-	if (server->tcpStatus == CifsNeedNegotiate)
-		echo_interval = 0;
-	else
-		echo_interval = server->echo_interval;
 
 	/*
 	 * We cannot send an echo if it is disabled.
@@ -412,7 +402,7 @@ cifs_echo_request(struct work_struct *work)
 	    server->tcpStatus == CifsExiting ||
 	    server->tcpStatus == CifsNew ||
 	    (server->ops->can_echo && !server->ops->can_echo(server)) ||
-	    time_before(jiffies, server->lstrp + echo_interval - HZ))
+	    time_before(jiffies, server->lstrp + server->echo_interval - HZ))
 		goto requeue_echo;
 
 	rc = server->ops->echo ? server->ops->echo(server) : -ENOSYS;
@@ -476,6 +466,7 @@ server_unresponsive(struct TCP_Server_Info *server)
 	 */
 	if ((server->tcpStatus == CifsGood ||
 	    server->tcpStatus == CifsNeedNegotiate) &&
+	    (!server->ops->can_echo || server->ops->can_echo(server)) &&
 	    time_after(jiffies, server->lstrp + 3 * server->echo_interval)) {
 		cifs_server_dbg(VFS, "has not responded in %lu seconds. Reconnecting...\n",
 			 (3 * server->echo_interval) / HZ);
@@ -3158,17 +3149,29 @@ out:
 int
 cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname)
 {
-	int rc = 0;
+	int rc;
 
-	smb3_parse_devname(devname, ctx);
+	if (devname) {
+		cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname);
+		rc = smb3_parse_devname(devname, ctx);
+		if (rc) {
+			cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc);
+			return rc;
+		}
+	}
 
 	if (mntopts) {
 		char *ip;
 
-		cifs_dbg(FYI, "%s: mntopts=%s\n", __func__, mntopts);
 		rc = smb3_parse_opt(mntopts, "ip", &ip);
-		if (!rc && !cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip,
+		if (rc) {
-						 strlen(ip))) {
+			cifs_dbg(VFS, "%s: failed to parse ip options: %d\n", __func__, rc);
+			return rc;
+		}
+
+		rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));
+		kfree(ip);
+		if (!rc) {
 			cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);
 			return -EINVAL;
 		}
@@ -3188,7 +3191,7 @@ cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const c
 		return -EINVAL;
 	}
 
-	return rc;
+	return 0;
 }
 
 static int

fs/cifs/dir.c

@@ -34,6 +34,7 @@
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
 #include "fs_context.h"
+#include "cifs_ioctl.h"
 
 static void
 renew_parental_timestamps(struct dentry *direntry)
@@ -430,6 +431,9 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry,
 	__u32 oplock;
 	struct cifsFileInfo *file_info;
 
+	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
+		return -EIO;
+
 	/*
 	 * Posix open is only called (at lookup time) for file create now. For
 	 * opens (rather than creates), because we do not know if it is a file
@@ -546,6 +550,9 @@ int cifs_create(struct user_namespace *mnt_userns, struct inode *inode,
 	cifs_dbg(FYI, "cifs_create parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
 		 inode, direntry, direntry);
 
+	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
 	rc = PTR_ERR(tlink);
 	if (IS_ERR(tlink))
@@ -583,6 +590,9 @@ int cifs_mknod(struct user_namespace *mnt_userns, struct inode *inode,
 		return -EINVAL;
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);

fs/cifs/file.c

@@ -45,6 +45,7 @@
 #include "fscache.h"
 #include "smbdirect.h"
 #include "fs_context.h"
+#include "cifs_ioctl.h"
 
 static inline int cifs_convert_flags(unsigned int flags)
 {
@@ -322,9 +323,12 @@ cifs_new_fileinfo(struct cifs_fid *fid, struct file *file,
 	cfile->dentry = dget(dentry);
 	cfile->f_flags = file->f_flags;
 	cfile->invalidHandle = false;
+	cfile->oplock_break_received = false;
+	cfile->deferred_scheduled = false;
 	cfile->tlink = cifs_get_tlink(tlink);
 	INIT_WORK(&cfile->oplock_break, cifs_oplock_break);
 	INIT_WORK(&cfile->put, cifsFileInfo_put_work);
+	INIT_DELAYED_WORK(&cfile->deferred, smb2_deferred_work_close);
 	mutex_init(&cfile->fh_mutex);
 	spin_lock_init(&cfile->file_info_lock);
 
@@ -539,6 +543,11 @@ int cifs_open(struct inode *inode, struct file *file)
 	xid = get_xid();
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb))) {
+		free_xid(xid);
+		return -EIO;
+	}
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink)) {
 		free_xid(xid);
@@ -565,6 +574,23 @@ int cifs_open(struct inode *inode, struct file *file)
 			file->f_op = &cifs_file_direct_ops;
 	}
 
+	spin_lock(&CIFS_I(inode)->deferred_lock);
+	/* Get the cached handle as SMB2 close is deferred */
+	rc = cifs_get_readable_path(tcon, full_path, &cfile);
+	if (rc == 0) {
+		if (file->f_flags == cfile->f_flags) {
+			file->private_data = cfile;
+			cifs_del_deferred_close(cfile);
+			spin_unlock(&CIFS_I(inode)->deferred_lock);
+			goto out;
+		} else {
+			spin_unlock(&CIFS_I(inode)->deferred_lock);
+			_cifsFileInfo_put(cfile, true, false);
+		}
+	} else {
+		spin_unlock(&CIFS_I(inode)->deferred_lock);
+	}
+
 	if (server->oplocks)
 		oplock = REQ_OPLOCK;
 	else
@@ -846,11 +872,56 @@ reopen_error_exit:
 	return rc;
 }
 
+void smb2_deferred_work_close(struct work_struct *work)
+{
+	struct cifsFileInfo *cfile = container_of(work,
+			struct cifsFileInfo, deferred.work);
+
+	spin_lock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+	if (!cfile->deferred_scheduled) {
+		spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+		return;
+	}
+	cifs_del_deferred_close(cfile);
+	cfile->deferred_scheduled = false;
+	spin_unlock(&CIFS_I(d_inode(cfile->dentry))->deferred_lock);
+	_cifsFileInfo_put(cfile, true, false);
+}
+
 int cifs_close(struct inode *inode, struct file *file)
 {
+	struct cifsFileInfo *cfile;
+	struct cifsInodeInfo *cinode = CIFS_I(inode);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifs_deferred_close *dclose;
+
 	if (file->private_data != NULL) {
-		_cifsFileInfo_put(file->private_data, true, false);
+		cfile = file->private_data;
 		file->private_data = NULL;
+		dclose = kmalloc(sizeof(struct cifs_deferred_close), GFP_KERNEL);
+		if ((cinode->oplock == CIFS_CACHE_RHW_FLG) &&
+		    dclose) {
+			if (test_bit(CIFS_INO_MODIFIED_ATTR, &cinode->flags))
+				inode->i_ctime = inode->i_mtime = current_time(inode);
+			spin_lock(&cinode->deferred_lock);
+			cifs_add_deferred_close(cfile, dclose);
+			if (cfile->deferred_scheduled) {
+				mod_delayed_work(deferredclose_wq,
+						&cfile->deferred, cifs_sb->ctx->acregmax);
+			} else {
+				/* Deferred close for files */
+				queue_delayed_work(deferredclose_wq,
+						&cfile->deferred, cifs_sb->ctx->acregmax);
+				cfile->deferred_scheduled = true;
+				spin_unlock(&cinode->deferred_lock);
+				return 0;
+			}
+			spin_unlock(&cinode->deferred_lock);
+			_cifsFileInfo_put(cfile, true, false);
+		} else {
+			_cifsFileInfo_put(cfile, true, false);
+			kfree(dclose);
+		}
 	}
 
 	/* return code from the ->release op is always ignored */
@@ -1920,8 +1991,10 @@ cifs_write(struct cifsFileInfo *open_file, __u32 pid, const char *write_data,
 
 	if (total_written > 0) {
 		spin_lock(&d_inode(dentry)->i_lock);
-		if (*offset > d_inode(dentry)->i_size)
+		if (*offset > d_inode(dentry)->i_size) {
 			i_size_write(d_inode(dentry), *offset);
+			d_inode(dentry)->i_blocks = (512 - 1 + *offset) >> 9;
+		}
 		spin_unlock(&d_inode(dentry)->i_lock);
 	}
 	mark_inode_dirty_sync(d_inode(dentry));
@@ -1947,7 +2020,8 @@ struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *cifs_inode,
 		if (fsuid_only && !uid_eq(open_file->uid, current_fsuid()))
 			continue;
 		if (OPEN_FMODE(open_file->f_flags) & FMODE_READ) {
-			if (!open_file->invalidHandle) {
+			if ((!open_file->invalidHandle) &&
+				(!open_file->oplock_break_received)) {
 				/* found a good file */
 				/* lock it so it will not be closed on us */
 				cifsFileInfo_get(open_file);
@@ -2476,6 +2550,8 @@ retry:
 	if (cfile)
 		cifsFileInfo_put(cfile);
 	free_xid(xid);
+	/* Indication to update ctime and mtime as close is deferred */
+	set_bit(CIFS_INO_MODIFIED_ATTR, &CIFS_I(inode)->flags);
 	return rc;
 }
 
@@ -2577,13 +2653,17 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
 
 	if (rc > 0) {
 		spin_lock(&inode->i_lock);
-		if (pos > inode->i_size)
+		if (pos > inode->i_size) {
 			i_size_write(inode, pos);
+			inode->i_blocks = (512 - 1 + pos) >> 9;
+		}
 		spin_unlock(&inode->i_lock);
 	}
 
 	unlock_page(page);
 	put_page(page);
+	/* Indication to update ctime and mtime as close is deferred */
+	set_bit(CIFS_INO_MODIFIED_ATTR, &CIFS_I(inode)->flags);
 
 	return rc;
 }
@@ -4744,6 +4824,8 @@ void cifs_oplock_break(struct work_struct *work)
 	struct TCP_Server_Info *server = tcon->ses->server;
 	int rc = 0;
 	bool purge_cache = false;
+	bool is_deferred = false;
+	struct cifs_deferred_close *dclose;
 
 	wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
 			TASK_UNINTERRUPTIBLE);
@@ -4790,6 +4872,18 @@ oplock_break_ack:
 							     cinode);
 		cifs_dbg(FYI, "Oplock release rc = %d\n", rc);
 	}
+	/*
+	 * When oplock break is received and there are no active
+	 * file handles but cached, then set the flag oplock_break_received.
+	 * So, new open will not use cached handle.
+	 */
+	spin_lock(&CIFS_I(inode)->deferred_lock);
+	is_deferred = cifs_is_deferred_close(cfile, &dclose);
+	if (is_deferred && cfile->deferred_scheduled) {
+		cfile->oplock_break_received = true;
+		mod_delayed_work(deferredclose_wq, &cfile->deferred, 0);
+	}
+	spin_unlock(&CIFS_I(inode)->deferred_lock);
 	_cifsFileInfo_put(cfile, false /* do not wait for ourself */, false);
 	cifs_done_oplock_break(cinode);
 }

fs/cifs/fs_context.c

@@ -476,6 +476,7 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
 
 	/* move "pos" up to delimiter or NULL */
 	pos += len;
+	kfree(ctx->UNC);
 	ctx->UNC = kstrndup(devname, pos - devname, GFP_KERNEL);
 	if (!ctx->UNC)
 		return -ENOMEM;
@@ -486,6 +487,9 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
 	if (*pos == '/' || *pos == '\\')
 		pos++;
 
+	kfree(ctx->prepath);
+	ctx->prepath = NULL;
+
 	/* If pos is NULL then no prepath */
 	if (!*pos)
 		return 0;
@@ -1642,6 +1646,7 @@ void smb3_update_mnt_flags(struct cifs_sb_info *cifs_sb)
 			cifs_dbg(VFS, "mount options mfsymlinks and sfu both enabled\n");
 		}
 	}
+	cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SHUTDOWN;
 
 	return;
 }

fs/cifs/inode.c

@@ -26,7 +26,6 @@
 #include <linux/sched/signal.h>
 #include <linux/wait_bit.h>
 #include <linux/fiemap.h>
-
 #include <asm/div64.h>
 #include "cifsfs.h"
 #include "cifspdu.h"
@@ -38,7 +37,7 @@
 #include "cifs_unicode.h"
 #include "fscache.h"
 #include "fs_context.h"
-
+#include "cifs_ioctl.h"
 
 static void cifs_set_ops(struct inode *inode)
 {
@@ -1610,6 +1609,9 @@ int cifs_unlink(struct inode *dir, struct dentry *dentry)
 
 	cifs_dbg(FYI, "cifs_unlink, dir=0x%p, dentry=0x%p\n", dir, dentry);
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -1632,6 +1634,7 @@ int cifs_unlink(struct inode *dir, struct dentry *dentry)
 		goto unlink_out;
 	}
 
+	cifs_close_all_deferred_files(tcon);
 	if (cap_unix(tcon->ses) && (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 				le64_to_cpu(tcon->fsUnixInfo.Capability))) {
 		rc = CIFSPOSIXDelFile(xid, tcon, full_path,
@@ -1872,6 +1875,8 @@ int cifs_mkdir(struct user_namespace *mnt_userns, struct inode *inode,
 		 mode, inode);
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -1954,6 +1959,11 @@ int cifs_rmdir(struct inode *inode, struct dentry *direntry)
 	}
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb))) {
+		rc = -EIO;
+		goto rmdir_exit;
+	}
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink)) {
 		rc = PTR_ERR(tlink);
@@ -2088,6 +2098,9 @@ cifs_rename2(struct user_namespace *mnt_userns, struct inode *source_dir,
 		return -EINVAL;
 
 	cifs_sb = CIFS_SB(source_dir->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -2109,6 +2122,7 @@ cifs_rename2(struct user_namespace *mnt_userns, struct inode *source_dir,
 		goto cifs_rename_exit;
 	}
 
+	cifs_close_all_deferred_files(tcon);
 	rc = cifs_do_rename(xid, source_dentry, from_name, target_dentry,
 			    to_name);
 
@@ -2404,6 +2418,9 @@ int cifs_getattr(struct user_namespace *mnt_userns, const struct path *path,
 	struct inode *inode = d_inode(dentry);
 	int rc;
 
+	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
+		return -EIO;
+
 	/*
 	 * We need to be sure that all dirty pages are written and the server
 	 * has actual ctime, mtime and file length.
@@ -2476,6 +2493,9 @@ int cifs_fiemap(struct inode *inode, struct fiemap_extent_info *fei, u64 start,
 	struct cifsFileInfo *cfile;
 	int rc;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	/*
 	 * We need to be sure that all dirty pages are written as they
 	 * might fill holes on the server.
@@ -2962,6 +2982,9 @@ cifs_setattr(struct user_namespace *mnt_userns, struct dentry *direntry,
 	struct cifs_tcon *pTcon = cifs_sb_master_tcon(cifs_sb);
 	int rc, retries = 0;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	do {
 		if (pTcon->unix_ext)
 			rc = cifs_setattr_unix(direntry, attrs);

fs/cifs/ioctl.c

@@ -164,6 +164,100 @@ static long smb_mnt_get_fsinfo(unsigned int xid, struct cifs_tcon *tcon,
 	return rc;
 }
 
+static int cifs_shutdown(struct super_block *sb, unsigned long arg)
+{
+	struct cifs_sb_info *sbi = CIFS_SB(sb);
+	__u32 flags;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (get_user(flags, (__u32 __user *)arg))
+		return -EFAULT;
+
+	if (flags > CIFS_GOING_FLAGS_NOLOGFLUSH)
+		return -EINVAL;
+
+	if (cifs_forced_shutdown(sbi))
+		return 0;
+
+	cifs_dbg(VFS, "shut down requested (%d)", flags);
+/*	trace_cifs_shutdown(sb, flags);*/
+
+	/*
+	 * see:
+	 *   https://man7.org/linux/man-pages/man2/ioctl_xfs_goingdown.2.html
+	 * for more information and description of original intent of the flags
+	 */
+	switch (flags) {
+	/*
+	 * We could add support later for default flag which requires:
+	 *     "Flush all dirty data and metadata to disk"
+	 * would need to call syncfs or equivalent to flush page cache for
+	 * the mount and then issue fsync to server (if nostrictsync not set)
+	 */
+	case CIFS_GOING_FLAGS_DEFAULT:
+		cifs_dbg(FYI, "shutdown with default flag not supported\n");
+		return -EINVAL;
+	/*
+	 * FLAGS_LOGFLUSH is easy since it asks to write out metadata (not
+	 * data) but metadata writes are not cached on the client, so can treat
+	 * it similarly to NOLOGFLUSH
+	 */
+	case CIFS_GOING_FLAGS_LOGFLUSH:
+	case CIFS_GOING_FLAGS_NOLOGFLUSH:
+		sbi->mnt_cifs_flags |= CIFS_MOUNT_SHUTDOWN;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int cifs_dump_full_key(struct cifs_tcon *tcon, unsigned long arg)
+{
+	struct smb3_full_key_debug_info pfull_key_inf;
+	__u64 suid;
+	struct list_head *tmp;
+	struct cifs_ses *ses;
+	bool found = false;
+
+	if (!smb3_encryption_required(tcon))
+		return -EOPNOTSUPP;
+
+	ses = tcon->ses; /* default to user id for current user */
+	if (get_user(suid, (__u64 __user *)arg))
+		suid = 0;
+	if (suid) {
+		/* search to see if there is a session with a matching SMB UID */
+		spin_lock(&cifs_tcp_ses_lock);
+		list_for_each(tmp, &tcon->ses->server->smb_ses_list) {
+			ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
+			if (ses->Suid == suid) {
+				found = true;
+				break;
+			}
+		}
+		spin_unlock(&cifs_tcp_ses_lock);
+		if (found == false)
+			return -EINVAL;
+	} /* else uses default user's SMB UID (ie current user) */
+
+	pfull_key_inf.cipher_type = le16_to_cpu(ses->server->cipher_type);
+	pfull_key_inf.Suid = ses->Suid;
+	memcpy(pfull_key_inf.auth_key, ses->auth_key.response,
+	       16 /* SMB2_NTLMV2_SESSKEY_SIZE */);
+	memcpy(pfull_key_inf.smb3decryptionkey, ses->smb3decryptionkey,
+	       32 /* SMB3_ENC_DEC_KEY_SIZE */);
+	memcpy(pfull_key_inf.smb3encryptionkey,
+	       ses->smb3encryptionkey, 32 /* SMB3_ENC_DEC_KEY_SIZE */);
+	if (copy_to_user((void __user *)arg, &pfull_key_inf,
+			 sizeof(struct smb3_full_key_debug_info)))
+		return -EFAULT;
+
+	return 0;
+}
+
 long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 {
 	struct inode *inode = file_inode(filep);
@@ -304,6 +398,21 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 			else
 				rc = 0;
 			break;
+		/*
+		 * Dump full key (32 bytes instead of 16 bytes) is
+		 * needed if GCM256 (stronger encryption) negotiated
+		 */
+		case CIFS_DUMP_FULL_KEY:
+			if (pSMBFile == NULL)
+				break;
+			if (!capable(CAP_SYS_ADMIN)) {
+				rc = -EACCES;
+				break;
+			}
+			tcon = tlink_tcon(pSMBFile->tlink);
+			rc = cifs_dump_full_key(tcon, arg);
+
+			break;
 		case CIFS_IOC_NOTIFY:
 			if (!S_ISDIR(inode->i_mode)) {
 				/* Notify can only be done on directories */
@@ -325,6 +434,9 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 				rc = -EOPNOTSUPP;
 			cifs_put_tlink(tlink);
 			break;
+		case CIFS_IOC_SHUTDOWN:
+			rc = cifs_shutdown(inode->i_sb, arg);
+			break;
 		default:
 			cifs_dbg(FYI, "unsupported ioctl\n");
 			break;

fs/cifs/link.c

@@ -30,6 +30,7 @@
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
 #include "smb2proto.h"
+#include "cifs_ioctl.h"
 
 /*
  * M-F Symlink Functions - Begin
@@ -518,6 +519,9 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	struct TCP_Server_Info *server;
 	struct cifsInodeInfo *cifsInode;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -679,9 +683,16 @@ cifs_symlink(struct user_namespace *mnt_userns, struct inode *inode,
 	struct tcon_link *tlink;
 	struct cifs_tcon *pTcon;
 	const char *full_path;
-	void *page = alloc_dentry_path();
+	void *page;
 	struct inode *newinode = NULL;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
+	page = alloc_dentry_path();
+	if (!page)
+		return -ENOMEM;
+
 	xid = get_xid();
 
 	tlink = cifs_sb_tlink(cifs_sb);

fs/cifs/misc.c

@@ -672,6 +672,85 @@ cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 }
 
+bool
+cifs_is_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close **pdclose)
+{
+	struct cifs_deferred_close *dclose;
+
+	list_for_each_entry(dclose, &CIFS_I(d_inode(cfile->dentry))->deferred_closes, dlist) {
+		if ((dclose->netfid == cfile->fid.netfid) &&
+			(dclose->persistent_fid == cfile->fid.persistent_fid) &&
+			(dclose->volatile_fid == cfile->fid.volatile_fid)) {
+			*pdclose = dclose;
+			return true;
+		}
+	}
+	return false;
+}
+
+void
+cifs_add_deferred_close(struct cifsFileInfo *cfile, struct cifs_deferred_close *dclose)
+{
+	bool is_deferred = false;
+	struct cifs_deferred_close *pdclose;
+
+	is_deferred = cifs_is_deferred_close(cfile, &pdclose);
+	if (is_deferred) {
+		kfree(dclose);
+		return;
+	}
+
+	dclose->tlink = cfile->tlink;
+	dclose->netfid = cfile->fid.netfid;
+	dclose->persistent_fid = cfile->fid.persistent_fid;
+	dclose->volatile_fid = cfile->fid.volatile_fid;
+	list_add_tail(&dclose->dlist, &CIFS_I(d_inode(cfile->dentry))->deferred_closes);
+}
+
+void
+cifs_del_deferred_close(struct cifsFileInfo *cfile)
+{
+	bool is_deferred = false;
+	struct cifs_deferred_close *dclose;
+
+	is_deferred = cifs_is_deferred_close(cfile, &dclose);
+	if (!is_deferred)
+		return;
+	list_del(&dclose->dlist);
+	kfree(dclose);
+}
+
+void
+cifs_close_deferred_file(struct cifsInodeInfo *cifs_inode)
+{
+	struct cifsFileInfo *cfile = NULL;
+	struct cifs_deferred_close *dclose;
+
+	list_for_each_entry(cfile, &cifs_inode->openFileList, flist) {
+		spin_lock(&cifs_inode->deferred_lock);
+		if (cifs_is_deferred_close(cfile, &dclose))
+			mod_delayed_work(deferredclose_wq, &cfile->deferred, 0);
+		spin_unlock(&cifs_inode->deferred_lock);
+	}
+}
+
+void
+cifs_close_all_deferred_files(struct cifs_tcon *tcon)
+{
+	struct cifsFileInfo *cfile;
+	struct cifsInodeInfo *cinode;
+	struct list_head *tmp;
+
+	spin_lock(&tcon->open_file_lock);
+	list_for_each(tmp, &tcon->openFileList) {
+		cfile = list_entry(tmp, struct cifsFileInfo, tlist);
+		cinode = CIFS_I(d_inode(cfile->dentry));
+		if (delayed_work_pending(&cfile->deferred))
+			mod_delayed_work(deferredclose_wq, &cfile->deferred, 0);
+	}
+	spin_unlock(&tcon->open_file_lock);
+}
+
 /* parses DFS refferal V3 structure
  * caller is responsible for freeing target_nodes
  * returns:

fs/cifs/xattr.c

@@ -30,6 +30,7 @@
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
+#include "cifs_ioctl.h"
 
 #define MAX_EA_VALUE_SIZE CIFSMaxBufSize
 #define CIFS_XATTR_CIFS_ACL "system.cifs_acl" /* DACL only */
@@ -421,6 +422,9 @@ ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 	const char *full_path;
 	void *page;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 		return -EOPNOTSUPP;