[PATCH] ReiserFS: Make sure all dentries refs are released before calling kill_block_super() [try #2]

[David Howells <dhowells@redhat.com>]

Make sure all dentries refs are released before calling kill_block_super() so
that the assumption that generic_shutdown_super() can completely destroy the
dentry tree for there will be no external references holds true.

What was being done in the put_super() superblock op, is now done in the
kill_sb() filesystem op instead, prior to calling kill_block_super().


Changes made in [try #2]:

 (*) reiserfs_kill_sb() now checks that the superblock FS info pointer is set
     before trying to dereference it.

Signed-Off-By: David Howells <dhowells@redhat.com>
---

 fs/reiserfs/super.c |   31 ++++++++++++++++++++-----------
 1 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
index 5567328..c6e327a 100644
--- a/fs/reiserfs/super.c
+++ b/fs/reiserfs/super.c
@@ -430,22 +430,31 @@ int remove_save_link(struct inode *inode
 	return journal_end(&th, inode->i_sb, JOURNAL_PER_BALANCE_CNT);
 }
 
+static void reiserfs_kill_sb(struct super_block *s)
+{
+	if (REISERFS_SB(s)) {
+		if (REISERFS_SB(s)->xattr_root) {
+			d_invalidate(REISERFS_SB(s)->xattr_root);
+			dput(REISERFS_SB(s)->xattr_root);
+			REISERFS_SB(s)->xattr_root = NULL;
+		}
+
+		if (REISERFS_SB(s)->priv_root) {
+			d_invalidate(REISERFS_SB(s)->priv_root);
+			dput(REISERFS_SB(s)->priv_root);
+			REISERFS_SB(s)->priv_root = NULL;
+		}
+	}
+
+	kill_block_super(s);
+}
+
 static void reiserfs_put_super(struct super_block *s)
 {
 	int i;
 	struct reiserfs_transaction_handle th;
 	th.t_trans_id = 0;
 
-	if (REISERFS_SB(s)->xattr_root) {
-		d_invalidate(REISERFS_SB(s)->xattr_root);
-		dput(REISERFS_SB(s)->xattr_root);
-	}
-
-	if (REISERFS_SB(s)->priv_root) {
-		d_invalidate(REISERFS_SB(s)->priv_root);
-		dput(REISERFS_SB(s)->priv_root);
-	}
-
 	/* change file system state to current state if it was mounted with read-write permissions */
 	if (!(s->s_flags & MS_RDONLY)) {
 		if (!journal_begin(&th, s, 10)) {
@@ -2300,7 +2309,7 @@ struct file_system_type reiserfs_fs_type
 	.owner = THIS_MODULE,
 	.name = "reiserfs",
 	.get_sb = get_super_block,
-	.kill_sb = kill_block_super,
+	.kill_sb = reiserfs_kill_sb,
 	.fs_flags = FS_REQUIRES_DEV,
 };