From ee3efa91e240f513898050ef305a49a653c8ed90 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 8 Jun 2012 15:59:33 -0400 Subject: [PATCH] __d_unalias() should refuse to move mountpoints Signed-off-by: Al Viro --- fs/dcache.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 015586f1ffc6..8086636bf796 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2387,14 +2387,13 @@ static struct dentry *__d_unalias(struct inode *inode, struct dentry *dentry, struct dentry *alias) { struct mutex *m1 = NULL, *m2 = NULL; - struct dentry *ret; + struct dentry *ret = ERR_PTR(-EBUSY); /* If alias and dentry share a parent, then no extra locks required */ if (alias->d_parent == dentry->d_parent) goto out_unalias; /* See lock_rename() */ - ret = ERR_PTR(-EBUSY); if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) goto out_err; m1 = &dentry->d_sb->s_vfs_rename_mutex; @@ -2402,8 +2401,10 @@ static struct dentry *__d_unalias(struct inode *inode, goto out_err; m2 = &alias->d_parent->d_inode->i_mutex; out_unalias: - __d_move(alias, dentry); - ret = alias; + if (likely(!d_mountpoint(alias))) { + __d_move(alias, dentry); + ret = alias; + } out_err: spin_unlock(&inode->i_lock); if (m2) -- 2.20.1