diff --git a/fs/fs_context.c b/fs/fs_context.c
index eb806fae311718961a95432c1c7f308f9203eb9e..dcf3786f90f9698c94416d2a9be3fcc76a49b2a1 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -11,6 +11,7 @@
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/module.h>
 #include <linux/fs_context.h>
 #include <linux/fs_parser.h>
 #include <linux/fs.h>
@@ -23,6 +24,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/user_namespace.h>
 #include <net/net_namespace.h>
+#include <asm/sections.h>
 #include "mount.h"
 #include "internal.h"
 
@@ -365,6 +367,8 @@ struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
 	get_net(fc->net_ns);
 	get_user_ns(fc->user_ns);
 	get_cred(fc->cred);
+	if (fc->log)
+		refcount_inc(&fc->log->usage);
 
 	/* Can't call put until we've called ->dup */
 	ret = fc->ops->dup(fc, src_fc);
@@ -382,7 +386,6 @@ struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
 }
 EXPORT_SYMBOL(vfs_dup_fs_context);
 
-#ifdef CONFIG_PRINTK
 /**
  * logfc - Log a message to a filesystem context
  * @fc: The filesystem context to log to.
@@ -390,27 +393,100 @@ EXPORT_SYMBOL(vfs_dup_fs_context);
  */
 void logfc(struct fs_context *fc, const char *fmt, ...)
 {
+	static const char store_failure[] = "OOM: Can't store error string";
+	struct fc_log *log = fc ? fc->log : NULL;
+	const char *p;
 	va_list va;
+	char *q;
+	u8 freeable;
 
 	va_start(va, fmt);
-
-	switch (fmt[0]) {
-	case 'w':
-		vprintk_emit(0, LOGLEVEL_WARNING, NULL, 0, fmt, va);
-		break;
-	case 'e':
-		vprintk_emit(0, LOGLEVEL_ERR, NULL, 0, fmt, va);
-		break;
-	default:
-		vprintk_emit(0, LOGLEVEL_NOTICE, NULL, 0, fmt, va);
-		break;
+	if (!strchr(fmt, '%')) {
+		p = fmt;
+		goto unformatted_string;
 	}
+	if (strcmp(fmt, "%s") == 0) {
+		p = va_arg(va, const char *);
+		goto unformatted_string;
+	}
+
+	q = kvasprintf(GFP_KERNEL, fmt, va);
+copied_string:
+	if (!q)
+		goto store_failure;
+	freeable = 1;
+	goto store_string;
+
+unformatted_string:
+	if ((unsigned long)p >= (unsigned long)__start_rodata &&
+	    (unsigned long)p <  (unsigned long)__end_rodata)
+		goto const_string;
+	if (log && within_module_core((unsigned long)p, log->owner))
+		goto const_string;
+	q = kstrdup(p, GFP_KERNEL);
+	goto copied_string;
+
+store_failure:
+	p = store_failure;
+const_string:
+	q = (char *)p;
+	freeable = 0;
+store_string:
+	if (!log) {
+		switch (fmt[0]) {
+		case 'w':
+			printk(KERN_WARNING "%s\n", q + 2);
+			break;
+		case 'e':
+			printk(KERN_ERR "%s\n", q + 2);
+			break;
+		default:
+			printk(KERN_NOTICE "%s\n", q + 2);
+			break;
+		}
+		if (freeable)
+			kfree(q);
+	} else {
+		unsigned int logsize = ARRAY_SIZE(log->buffer);
+		u8 index;
+
+		index = log->head & (logsize - 1);
+		BUILD_BUG_ON(sizeof(log->head) != sizeof(u8) ||
+			     sizeof(log->tail) != sizeof(u8));
+		if ((u8)(log->head - log->tail) == logsize) {
+			/* The buffer is full, discard the oldest message */
+			if (log->need_free & (1 << index))
+				kfree(log->buffer[index]);
+			log->tail++;
+		}
 
-	pr_cont("\n");
+		log->buffer[index] = q;
+		log->need_free &= ~(1 << index);
+		log->need_free |= freeable << index;
+		log->head++;
+	}
 	va_end(va);
 }
 EXPORT_SYMBOL(logfc);
-#endif
+
+/*
+ * Free a logging structure.
+ */
+static void put_fc_log(struct fs_context *fc)
+{
+	struct fc_log *log = fc->log;
+	int i;
+
+	if (log) {
+		if (refcount_dec_and_test(&log->usage)) {
+			fc->log = NULL;
+			for (i = 0; i <= 7; i++)
+				if (log->need_free & (1 << i))
+					kfree(log->buffer[i]);
+			kfree(log);
+		}
+	}
+}
 
 /**
  * put_fs_context - Dispose of a superblock configuration context.
@@ -435,6 +511,7 @@ void put_fs_context(struct fs_context *fc)
 	put_user_ns(fc->user_ns);
 	put_cred(fc->cred);
 	kfree(fc->subtype);
+	put_fc_log(fc);
 	put_filesystem(fc->fs_type);
 	kfree(fc->source);
 	kfree(fc);
diff --git a/fs/fsopen.c b/fs/fsopen.c
index d256f1ac9ff1bf1158b483b7c7efc85abc55a367..5fce6347de7a1f276d872e6b5129c0c5fa1178b2 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -20,6 +20,52 @@
 #include <uapi/linux/mount.h>
 #include "mount.h"
 
+/*
+ * Allow the user to read back any error, warning or informational messages.
+ */
+static ssize_t fscontext_read(struct file *file,
+			      char __user *_buf, size_t len, loff_t *pos)
+{
+	struct fs_context *fc = file->private_data;
+	struct fc_log *log = fc->log;
+	unsigned int logsize = ARRAY_SIZE(log->buffer);
+	ssize_t ret;
+	char *p;
+	bool need_free;
+	int index, n;
+
+	ret = mutex_lock_interruptible(&fc->uapi_mutex);
+	if (ret < 0)
+		return ret;
+
+	if (log->head == log->tail) {
+		mutex_unlock(&fc->uapi_mutex);
+		return -ENODATA;
+	}
+
+	index = log->tail & (logsize - 1);
+	p = log->buffer[index];
+	need_free = log->need_free & (1 << index);
+	log->buffer[index] = NULL;
+	log->need_free &= ~(1 << index);
+	log->tail++;
+	mutex_unlock(&fc->uapi_mutex);
+
+	ret = -EMSGSIZE;
+	n = strlen(p);
+	if (n > len)
+		goto err_free;
+	ret = -EFAULT;
+	if (copy_to_user(_buf, p, n) != 0)
+		goto err_free;
+	ret = n;
+
+err_free:
+	if (need_free)
+		kfree(p);
+	return ret;
+}
+
 static int fscontext_release(struct inode *inode, struct file *file)
 {
 	struct fs_context *fc = file->private_data;
@@ -32,6 +78,7 @@ static int fscontext_release(struct inode *inode, struct file *file)
 }
 
 const struct file_operations fscontext_fops = {
+	.read		= fscontext_read,
 	.release	= fscontext_release,
 	.llseek		= no_llseek,
 };
@@ -50,6 +97,16 @@ static int fscontext_create_fd(struct fs_context *fc, unsigned int o_flags)
 	return fd;
 }
 
+static int fscontext_alloc_log(struct fs_context *fc)
+{
+	fc->log = kzalloc(sizeof(*fc->log), GFP_KERNEL);
+	if (!fc->log)
+		return -ENOMEM;
+	refcount_set(&fc->log->usage, 1);
+	fc->log->owner = fc->fs_type->owner;
+	return 0;
+}
+
 /*
  * Open a filesystem by name so that it can be configured for mounting.
  *
@@ -62,6 +119,7 @@ SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
 	struct file_system_type *fs_type;
 	struct fs_context *fc;
 	const char *fs_name;
+	int ret;
 
 	if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
 		return -EPERM;
@@ -84,5 +142,14 @@ SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
 		return PTR_ERR(fc);
 
 	fc->phase = FS_CONTEXT_CREATE_PARAMS;
+
+	ret = fscontext_alloc_log(fc);
+	if (ret < 0)
+		goto err_fc;
+
 	return fscontext_create_fd(fc, flags & FSOPEN_CLOEXEC ? O_CLOEXEC : 0);
+
+err_fc:
+	put_fs_context(fc);
+	return ret;
 }
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 7ab8b44fab3ef551581d5649ea96c2952caed839..1f966670c8dc7b40113fbb6a27cb8f8a00fad644 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -13,6 +13,7 @@
 #define _LINUX_FS_CONTEXT_H
 
 #include <linux/kernel.h>
+#include <linux/refcount.h>
 #include <linux/errno.h>
 #include <linux/security.h>
 #include <linux/mutex.h>
@@ -95,6 +96,7 @@ struct fs_context {
 	struct user_namespace	*user_ns;	/* The user namespace for this mount */
 	struct net		*net_ns;	/* The network namespace for this mount */
 	const struct cred	*cred;		/* The mounter's credentials */
+	struct fc_log		*log;		/* Logging buffer */
 	const char		*source;	/* The source name (eg. dev path) */
 	const char		*subtype;	/* The subtype to set on the superblock */
 	void			*security;	/* Linux S&M options */
@@ -151,15 +153,21 @@ extern int vfs_get_super(struct fs_context *fc,
 
 extern const struct file_operations fscontext_fops;
 
-#ifdef CONFIG_PRINTK
+/*
+ * Mount error, warning and informational message logging.  This structure is
+ * shareable between a mount and a subordinate mount.
+ */
+struct fc_log {
+	refcount_t	usage;
+	u8		head;		/* Insertion index in buffer[] */
+	u8		tail;		/* Removal index in buffer[] */
+	u8		need_free;	/* Mask of kfree'able items in buffer[] */
+	struct module	*owner;		/* Owner module for strings that don't then need freeing */
+	char		*buffer[8];
+};
+
 extern __attribute__((format(printf, 2, 3)))
 void logfc(struct fs_context *fc, const char *fmt, ...);
-#else
-static inline __attribute__((format(printf, 2, 3)))
-void logfc(struct fs_context *fc, const char *fmt, ...)
-{
-}
-#endif
 
 /**
  * infof - Store supplementary informational message
diff --git a/include/linux/module.h b/include/linux/module.h
index 5bf5dcd91009eeac5f725ceb727f1f984e065458..7dc4dc79b6341846d0e2b3da3a82b66188dc682b 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -709,6 +709,12 @@ static inline bool is_module_text_address(unsigned long addr)
 	return false;
 }
 
+static inline bool within_module_core(unsigned long addr,
+				      const struct module *mod)
+{
+	return false;
+}
+
 /* Get/put a kernel symbol (calls should be symmetric) */
 #define symbol_get(x) ({ extern typeof(x) x __attribute__((weak)); &(x); })
 #define symbol_put(x) do { } while (0)