1 files changed, 26 insertions, 4 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 1d5cf511e1c7..f9693da3efbd 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -398,7 +398,7 @@ repeat:
                 return;
         }
 
-        if (dentry->d_op && dentry->d_op->d_delete) {
+        if (dentry->d_flags & DCACHE_OP_DELETE) {
                 if (dentry->d_op->d_delete(dentry))
                         goto kill_it;
         }
@@ -1301,6 +1301,28 @@ struct dentry *d_alloc_name(struct dentry *parent, const char *name)
 }
 EXPORT_SYMBOL(d_alloc_name);
 
+void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op)
+{
+        BUG_ON(dentry->d_op);
+        BUG_ON(dentry->d_flags & (DCACHE_OP_HASH        |
+                                DCACHE_OP_COMPARE       |
+                                DCACHE_OP_REVALIDATE    |
+                                DCACHE_OP_DELETE ));
+        dentry->d_op = op;
+        if (!op)
+                return;
+        if (op->d_hash)
+                dentry->d_flags |= DCACHE_OP_HASH;
+        if (op->d_compare)
+                dentry->d_flags |= DCACHE_OP_COMPARE;
+        if (op->d_revalidate)
+                dentry->d_flags |= DCACHE_OP_REVALIDATE;
+        if (op->d_delete)
+                dentry->d_flags |= DCACHE_OP_DELETE;
+
+}
+EXPORT_SYMBOL(d_set_d_op);
+
 static void __d_instantiate(struct dentry *dentry, struct inode *inode)
 {
         spin_lock(&dentry->d_lock);
@@ -1731,7 +1753,7 @@ seqretry:
                  */
                 if (read_seqcount_retry(&dentry->d_seq, *seq))
                         goto seqretry;
-                if (parent->d_op && parent->d_op->d_compare) {
+                if (parent->d_flags & DCACHE_OP_COMPARE) {
                         if (parent->d_op->d_compare(parent, *inode,
                                                 dentry, i,
                                                 tlen, tname, name))
@@ -1846,7 +1868,7 @@ struct dentry *__d_lookup(struct dentry *parent, struct qstr *name)
                  */
                 tlen = dentry->d_name.len;
                 tname = dentry->d_name.name;
-                if (parent->d_op && parent->d_op->d_compare) {
+                if (parent->d_flags & DCACHE_OP_COMPARE) {
                         if (parent->d_op->d_compare(parent, parent->d_inode,
                                                 dentry, dentry->d_inode,
                                                 tlen, tname, name))
@@ -1887,7 +1909,7 @@ struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
          * routine may choose to leave the hash value unchanged.
          */
         name->hash = full_name_hash(name->name, name->len);
-        if (dir->d_op && dir->d_op->d_hash) {
+        if (dir->d_flags & DCACHE_OP_HASH) {
                 if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0)
                         goto out;
         }