efivarfs: automatically update super block flag

[sfrench/cifs-2.6.git] / fs / efivarfs / super.c

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index cee325b5bbdd97f516bd056cce390570344505ec..6038dd39367abe41430c55b04448ced7727dd287 100644 (file)
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -15,10 +15,30 @@
 #include <linux/slab.h>
 #include <linux/magic.h>
 #include <linux/statfs.h>
+#include <linux/notifier.h>
 #include <linux/printk.h>
 
 #include "internal.h"
 
+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)
 {
        clear_inode(inode);
@@ -317,6 +337,12 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
        if (!root)
                return -ENOMEM;
 
+       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,
                          &sfi->efivarfs_list);
        if (err)
@@ -371,6 +397,7 @@ static void efivarfs_kill_sb(struct super_block *sb)
 {
        struct efivarfs_fs_info *sfi = sb->s_fs_info;
 
+       blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
        kill_litter_super(sb);
 
        /* Remove all entries and destroy */