rpc_pipe: set dentry operations at d_alloc time

Currently the way these get set is a little convoluted. If the dentry is
allocated via lookup from userland, then it gets set by simple_lookup.
If it gets allocated when the kernel is populating the directory, then
it gets set via __rpc_lookup_create_exclusive, which has to check
whether they might already be set. Between both of these, this ensures
that all dentries have their d_op pointer set.

Instead of doing that, just have them set at d_alloc time by pointing
sb->s_d_op at them. With that change, we no longer want the lookup op
to set them, so we must move to using our own lookup routine.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 20 insertions, 5 deletions

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 4679df5a6d50..c5f6812ca06a 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -480,6 +480,23 @@ static const struct dentry_operations rpc_dentry_operations = {
         .d_delete = rpc_delete_dentry,
 };
 
+/*
+ * Lookup the data. This is trivial - if the dentry didn't already
+ * exist, we know it is negative.
+ */
+static struct dentry *
+rpc_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+        if (dentry->d_name.len > NAME_MAX)
+                return ERR_PTR(-ENAMETOOLONG);
+        d_add(dentry, NULL);
+        return NULL;
+}
+
+const struct inode_operations rpc_dir_inode_operations = {
+        .lookup         = rpc_lookup,
+};
+
 static struct inode *
 rpc_get_inode(struct super_block *sb, umode_t mode)
 {
@@ -492,7 +509,7 @@ rpc_get_inode(struct super_block *sb, umode_t mode)
         switch (mode & S_IFMT) {
         case S_IFDIR:
                 inode->i_fop = &simple_dir_operations;
-                inode->i_op = &simple_dir_inode_operations;
+                inode->i_op = &rpc_dir_inode_operations;
                 inc_nlink(inode);
         default:
                 break;
@@ -666,11 +683,8 @@ static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
                 if (!dentry)
                         return ERR_PTR(-ENOMEM);
         }
-        if (dentry->d_inode == NULL) {
-                if (!dentry->d_op)
-                        d_set_d_op(dentry, &rpc_dentry_operations);
+        if (dentry->d_inode == NULL)
                 return dentry;
-        }
         dput(dentry);
         return ERR_PTR(-EEXIST);
 }
@@ -1117,6 +1131,7 @@ rpc_fill_super(struct super_block *sb, void *data, int silent)
         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
         sb->s_magic = RPCAUTH_GSSMAGIC;
         sb->s_op = &s_ops;
+        sb->s_d_op = &rpc_dentry_operations;
         sb->s_time_gran = 1;
 
         inode = rpc_get_inode(sb, S_IFDIR | S_IRUGO | S_IXUGO);