From 0715b656ac88ce1bb62800b14d99ef2e25c26d28 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 29 May 2012 21:19:01 +0200 Subject: [PATCH 1/4] vfs: Avoid creation of directory loops for corrupted filesystems When a directory hierarchy is corrupted (e. g. due to a bit flip on the media), it can happen that it contains loops of directories. That creates possibilities for deadlock when locking directories. Fix the problem by checking in d_splice_alias() that when we splice a directory, it does not have any other connected alias. Reported-by: Sami Liedes Signed-off-by: Jan Kara --- fs/dcache.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 4435d8b..ca31a1e 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1658,6 +1658,10 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) d_move(new, dentry); iput(inode); } else { + if (unlikely(!list_empty(&inode->i_dentry))) { + spin_unlock(&inode->i_lock); + return ERR_PTR(-EIO); + } /* already taking inode->i_lock, so d_add() by hand */ __d_instantiate(dentry, inode); spin_unlock(&inode->i_lock); -- 1.7.1