hpfs: make freeing sbi and codetables rcu-delayed

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

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

diff --git a/fs/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h
index 1b39863..6797bf8 100644 (file)
--- a/fs/hpfs/hpfs_fn.h
+++ b/fs/hpfs/hpfs_fn.h
@@ -80,6 +80,7 @@ struct hpfs_sb_info {
        unsigned sb_c_bitmap;           /* current bitmap */
        unsigned sb_max_fwd_alloc;      /* max forwad allocation */
        int sb_timeshift;
+       struct rcu_head rcu;
 };
 
 /* Four 512-byte buffers and the 2k block obtained by concatenating them */

diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
index 4334cda..b8d01ef 100644 (file)
--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -101,18 +101,24 @@ int hpfs_stop_cycles(struct super_block *s, int key, int *c1, int *c2,
        return 0;
 }
 
-static void hpfs_put_super(struct super_block *s)
+static void free_sbi(struct hpfs_sb_info *sbi)
 {
-       struct hpfs_sb_info *sbi = hpfs_sb(s);
+       kfree(sbi->sb_cp_table);
+       kfree(sbi->sb_bmp_dir);
+       kfree(sbi);
+}
 
+static void lazy_free_sbi(struct rcu_head *rcu)
+{
+       free_sbi(container_of(rcu, struct hpfs_sb_info, rcu));
+}
+
+static void hpfs_put_super(struct super_block *s)
+{
        hpfs_lock(s);
        unmark_dirty(s);
        hpfs_unlock(s);
-
-       kfree(sbi->sb_cp_table);
-       kfree(sbi->sb_bmp_dir);
-       s->s_fs_info = NULL;
-       kfree(sbi);
+       call_rcu(&hpfs_sb(s)->rcu, lazy_free_sbi);
 }
 
 unsigned hpfs_count_one_bitmap(struct super_block *s, secno secno)
@@ -485,9 +491,6 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
        }
        s->s_fs_info = sbi;
 
-       sbi->sb_bmp_dir = NULL;
-       sbi->sb_cp_table = NULL;
-
        mutex_init(&sbi->hpfs_mutex);
        hpfs_lock(s);
 
@@ -679,10 +682,7 @@ bail2:     brelse(bh0);
 bail1:
 bail0:
        hpfs_unlock(s);
-       kfree(sbi->sb_bmp_dir);
-       kfree(sbi->sb_cp_table);
-       s->s_fs_info = NULL;
-       kfree(sbi);
+       free_sbi(sbi);
        return -EINVAL;
 }