From a10db50a4ae813fcb2f431f2fb039933c109a925 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 12 Dec 2007 11:12:15 -0500 Subject: NFS: Fix an Oops in NFS unmount Ensure that the dummy 'root dentry' is invisible to d_find_alias(). If not, then it may be spliced into the tree if a parent directory from the same filesystem gets mounted at a later time. Signed-off-by: Trond Myklebust --- fs/nfs/getroot.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c index 0ee4384..e6242cd 100644 --- a/fs/nfs/getroot.c +++ b/fs/nfs/getroot.c @@ -57,6 +57,17 @@ static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *i } /* Circumvent igrab(): we know the inode is not being freed */ atomic_inc(&inode->i_count); + /* + * Ensure that this dentry is invisible to d_find_alias(). + * Otherwise, it may be spliced into the tree by + * d_materialise_unique if a parent directory from the same + * filesystem gets mounted at a later time. + * This again causes shrink_dcache_for_umount_subtree() to + * Oops, since the test for IS_ROOT() will fail. + */ + spin_lock(&dcache_lock); + list_del_init(&sb->s_root->d_alias); + spin_unlock(&dcache_lock); } return 0; } -- cgit v1.1