adfs: delayed freeing of sbi

makes ->d_hash() and ->d_compare() safety in RCU mode independent
from vfsmount_lock.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 7 insertions, 5 deletions

diff --git a/fs/adfs/adfs.h b/fs/adfs/adfs.h
index 585adafb0cc2..c770337c4b45 100644
--- a/fs/adfs/adfs.h
+++ b/fs/adfs/adfs.h
@@ -43,9 +43,12 @@ struct adfs_dir_ops;
  * ADFS file system superblock data in memory
  */
 struct adfs_sb_info {
-        struct adfs_discmap *s_map;     /* bh list containing map                */
-        struct adfs_dir_ops *s_dir;     /* directory operations                  */
-
+        union { struct {
+                struct adfs_discmap *s_map;     /* bh list containing map        */
+                struct adfs_dir_ops *s_dir;     /* directory operations          */
+                };
+                struct rcu_head rcu;            /* used only at shutdown time    */
+        };
         kuid_t          s_uid;          /* owner uid                             */
         kgid_t          s_gid;          /* owner gid                             */
         umode_t         s_owner_mask;   /* ADFS owner perm -> unix perm          */
diff --git a/fs/adfs/super.c b/fs/adfs/super.c
index 0ff4bae2c2a2..7b3003cb6f1b 100644
--- a/fs/adfs/super.c
+++ b/fs/adfs/super.c
@@ -123,8 +123,7 @@ static void adfs_put_super(struct super_block *sb)
         for (i = 0; i < asb->s_map_size; i++)
                 brelse(asb->s_map[i].dm_bh);
         kfree(asb->s_map);
-        kfree(asb);
-        sb->s_fs_info = NULL;
+        kfree_rcu(asb, rcu);
 }
 
 static int adfs_show_options(struct seq_file *seq, struct dentry *root)