[PATCH v3 2/2] hfsplus: ensure sb->s_fs_info is always cleaned up

[Mehdi Ben Hadj Khelifa]

When hfsplus was converted to the new mount api a bug was introduced by
changing the allocation pattern of sb->s_fs_info. If setup_bdev_super()
fails after a new superblock has been allocated by sget_fc(), but before
hfsplus_fill_super() takes ownership of the filesystem-specific s_fs_info
data it was leaked.

Fix this by freeing sb->s_fs_info in hfsplus_kill_super().

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 432f7c78cb00 ("hfsplus: convert hfsplus to use the new mount api")
Reported-by: Viacheslav Dubeyko <Slava.Dubeyko@xxxxxxx> 
Tested-by: Viacheslav Dubeyko <Slava.Dubeyko@xxxxxxx>
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@xxxxxxxxx>
---
 fs/hfsplus/super.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 16bc4abc67e0..8734520f6419 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -328,8 +328,6 @@ static void hfsplus_put_super(struct super_block *sb)
 	hfs_btree_close(sbi->ext_tree);
 	kfree(sbi->s_vhdr_buf);
 	kfree(sbi->s_backup_vhdr_buf);
-	call_rcu(&sbi->rcu, delayed_free);
-
 	hfs_dbg("finished\n");
 }
 
@@ -629,7 +627,6 @@ static int hfsplus_fill_super(struct super_block *sb, struct fs_context *fc)
 out_unload_nls:
 	unload_nls(sbi->nls);
 	unload_nls(nls);
-	kfree(sbi);
 	return err;
 }
 
@@ -688,10 +685,18 @@ static int hfsplus_init_fs_context(struct fs_context *fc)
 	return 0;
 }
 
+static void hfsplus_kill_super(struct super_block *sb)
+{
+	struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+
+	kill_block_super(sb);
+	call_rcu(&sbi->rcu, delayed_free);
+}
+
 static struct file_system_type hfsplus_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "hfsplus",
-	.kill_sb	= kill_block_super,
+	.kill_sb	= hfsplus_kill_super,
 	.fs_flags	= FS_REQUIRES_DEV,
 	.init_fs_context = hfsplus_init_fs_context,
 };
-- 
2.52.0