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authorTrond Myklebust <Trond.Myklebust@netapp.com>2007-12-12 11:12:15 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2007-12-12 11:12:15 -0500
commita10db50a4ae813fcb2f431f2fb039933c109a925 (patch)
tree0c07781c5de3b7445add25db6d3471d71cf5cb86
parenta5576cfa5cd8d8aa874bd4ee500dc8a2e7cbad18 (diff)
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 <Trond.Myklebust@netapp.com>
-rw-r--r--fs/nfs/getroot.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/fs/nfs/getroot.c b/fs/nfs/getroot.c
index 0ee43843f4e..e6242cdbaf9 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;
}