1 files changed, 53 insertions, 13 deletions

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 77240953a92e..6038dd39367a 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -15,10 +15,29 @@
 #include <linux/slab.h>
 #include <linux/magic.h>
 #include <linux/statfs.h>
+#include <linux/notifier.h>
+#include <linux/printk.h>
 
 #include "internal.h"
 
-LIST_HEAD(efivarfs_list);
+static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event,
+				 void *data)
+{
+	struct efivarfs_fs_info *sfi = container_of(nb, struct efivarfs_fs_info, nb);
+
+	switch (event) {
+	case EFIVAR_OPS_RDONLY:
+		sfi->sb->s_flags |= SB_RDONLY;
+		break;
+	case EFIVAR_OPS_RDWR:
+		sfi->sb->s_flags &= ~SB_RDONLY;
+		break;
+	default:
+		return NOTIFY_DONE;
+	}
+
+	return NOTIFY_OK;
+}
 
 static void efivarfs_evict_inode(struct inode *inode)
 {
@@ -166,7 +185,8 @@ static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
 }
 
 static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
-			     unsigned long name_size, void *data)
+			     unsigned long name_size, void *data,
+			     struct list_head *list)
 {
 	struct super_block *sb = (struct super_block *)data;
 	struct efivar_entry *entry;
@@ -221,7 +241,7 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 	}
 
 	__efivar_entry_get(entry, NULL, &size, NULL);
-	__efivar_entry_add(entry, &efivarfs_list);
+	__efivar_entry_add(entry, list);
 
 	/* copied by the above to local storage in the dentry. */
 	kfree(name);
@@ -291,13 +311,11 @@ static int efivarfs_parse_param(struct fs_context *fc, struct fs_parameter *para
 
 static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
 {
+	struct efivarfs_fs_info *sfi = sb->s_fs_info;
 	struct inode *inode = NULL;
 	struct dentry *root;
 	int err;
 
-	if (!efivar_is_available())
-		return -EOPNOTSUPP;
-
 	sb->s_maxbytes          = MAX_LFS_FILESIZE;
 	sb->s_blocksize         = PAGE_SIZE;
 	sb->s_blocksize_bits    = PAGE_SHIFT;
@@ -319,11 +337,16 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (!root)
 		return -ENOMEM;
 
-	INIT_LIST_HEAD(&efivarfs_list);
+	sfi->sb = sb;
+	sfi->nb.notifier_call = efivarfs_ops_notifier;
+	err = blocking_notifier_chain_register(&efivar_ops_nh, &sfi->nb);
+	if (err)
+		return err;
 
-	err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list);
+	err = efivar_init(efivarfs_callback, (void *)sb, true,
+			  &sfi->efivarfs_list);
 	if (err)
-		efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);
+		efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
 
 	return err;
 }
@@ -333,19 +356,35 @@ static int efivarfs_get_tree(struct fs_context *fc)
 	return get_tree_single(fc, efivarfs_fill_super);
 }
 
+static int efivarfs_reconfigure(struct fs_context *fc)
+{
+	if (!efivar_supports_writes() && !(fc->sb_flags & SB_RDONLY)) {
+		pr_err("Firmware does not support SetVariableRT. Can not remount with rw\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static const struct fs_context_operations efivarfs_context_ops = {
 	.get_tree	= efivarfs_get_tree,
 	.parse_param	= efivarfs_parse_param,
+	.reconfigure	= efivarfs_reconfigure,
 };
 
 static int efivarfs_init_fs_context(struct fs_context *fc)
 {
 	struct efivarfs_fs_info *sfi;
 
+	if (!efivar_is_available())
+		return -EOPNOTSUPP;
+
 	sfi = kzalloc(sizeof(*sfi), GFP_KERNEL);
 	if (!sfi)
 		return -ENOMEM;
 
+	INIT_LIST_HEAD(&sfi->efivarfs_list);
+
 	sfi->mount_opts.uid = GLOBAL_ROOT_UID;
 	sfi->mount_opts.gid = GLOBAL_ROOT_GID;
 
@@ -356,13 +395,14 @@ static int efivarfs_init_fs_context(struct fs_context *fc)
 
 static void efivarfs_kill_sb(struct super_block *sb)
 {
-	kill_litter_super(sb);
+	struct efivarfs_fs_info *sfi = sb->s_fs_info;
 
-	if (!efivar_is_available())
-		return;
+	blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
+	kill_litter_super(sb);
 
 	/* Remove all entries and destroy */
-	efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);
+	efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
+	kfree(sfi);
 }
 
 static struct file_system_type efivarfs_type = {