1 files changed, 31 insertions, 4 deletions

diff --git a/fs/fs_context.c b/fs/fs_context.c
index 30d82d2979af..a0ad7a0c4680 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -162,6 +162,10 @@ EXPORT_SYMBOL(vfs_parse_fs_param);
 
 /**
  * vfs_parse_fs_string - Convenience function to just parse a string.
+ * @fc: Filesystem context.
+ * @key: Parameter name.
+ * @value: Default value.
+ * @v_size: Maximum number of bytes in the value.
  */
 int vfs_parse_fs_string(struct fs_context *fc, const char *key,
 			const char *value, size_t v_size)
@@ -189,7 +193,7 @@ EXPORT_SYMBOL(vfs_parse_fs_string);
 
 /**
  * generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
- * @ctx: The superblock configuration to fill in.
+ * @fc: The superblock configuration to fill in.
  * @data: The data to parse
  *
  * Parse a blob of data that's in key[=val][,key[=val]]* form.  This can be
@@ -315,10 +319,31 @@ struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
 }
 EXPORT_SYMBOL(fs_context_for_reconfigure);
 
+/**
+ * fs_context_for_submount: allocate a new fs_context for a submount
+ * @type: file_system_type of the new context
+ * @reference: reference dentry from which to copy relevant info
+ *
+ * Allocate a new fs_context suitable for a submount. This also ensures that
+ * the fc->security object is inherited from @reference (if needed).
+ */
 struct fs_context *fs_context_for_submount(struct file_system_type *type,
 					   struct dentry *reference)
 {
-	return alloc_fs_context(type, reference, 0, 0, FS_CONTEXT_FOR_SUBMOUNT);
+	struct fs_context *fc;
+	int ret;
+
+	fc = alloc_fs_context(type, reference, 0, 0, FS_CONTEXT_FOR_SUBMOUNT);
+	if (IS_ERR(fc))
+		return fc;
+
+	ret = security_fs_context_submount(fc, reference->d_sb);
+	if (ret) {
+		put_fs_context(fc);
+		return ERR_PTR(ret);
+	}
+
+	return fc;
 }
 EXPORT_SYMBOL(fs_context_for_submount);
 
@@ -333,7 +358,7 @@ void fc_drop_locked(struct fs_context *fc)
 static void legacy_fs_context_free(struct fs_context *fc);
 
 /**
- * vfs_dup_fc_config: Duplicate a filesystem context.
+ * vfs_dup_fs_context - Duplicate a filesystem context.
  * @src_fc: The context to copy.
  */
 struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
@@ -379,7 +404,9 @@ EXPORT_SYMBOL(vfs_dup_fs_context);
 
 /**
  * logfc - Log a message to a filesystem context
- * @fc: The filesystem context to log to.
+ * @log: The filesystem context to log to, or NULL to use printk.
+ * @prefix: A string to prefix the output with, or NULL.
+ * @level: 'w' for a warning, 'e' for an error.  Anything else is a notice.
  * @fmt: The format of the buffer.
  */
 void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...)