d_hash_and_lookup(): export, switch open-coded instances

* calling conventions change - ERR_PTR() is returned on ->d_hash() errors;
NULL is just for dcache miss now.
* exported, open-coded instances in ncpfs and cifs converted.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/cifs/readdir.c

@@ -82,12 +82,10 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
 
 	cFYI(1, "%s: for %s", __func__, name->name);
 
-	if (parent->d_op && parent->d_op->d_hash)
-		parent->d_op->d_hash(parent, parent->d_inode, name);
-	else
-		name->hash = full_name_hash(name->name, name->len);
+	dentry = d_hash_and_lookup(parent, name);
+	if (unlikely(IS_ERR(dentry)))
+		return;
 
-	dentry = d_lookup(parent, name);
 	if (dentry) {
 		int err;
 

fs/dcache.c

@@ -1672,7 +1672,6 @@ EXPORT_SYMBOL(d_splice_alias);
 struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 			struct qstr *name)
 {
-	int error;
 	struct dentry *found;
 	struct dentry *new;
 
@@ -1681,10 +1680,12 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 	 * if not go ahead and create it now.
 	 */
 	found = d_hash_and_lookup(dentry->d_parent, name);
+	if (unlikely(IS_ERR(found)))
+		goto err_out;
 	if (!found) {
 		new = d_alloc(dentry->d_parent, name);
 		if (!new) {
-			error = -ENOMEM;
+			found = ERR_PTR(-ENOMEM);
 			goto err_out;
 		}
 
@@ -1725,7 +1726,7 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
 
 err_out:
 	iput(inode);
-	return ERR_PTR(error);
+	return found;
 }
 EXPORT_SYMBOL(d_add_ci);
 
@@ -1997,12 +1998,10 @@ struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name)
  * @dir: Directory to search in
  * @name: qstr of name we wish to find
  *
- * On hash failure or on lookup failure NULL is returned.
+ * On lookup failure NULL is returned; on bad name - ERR_PTR(-error)
  */
 struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
 {
-	struct dentry *dentry = NULL;
-
 	/*
 	 * Check for a fs-specific hash function. Note that we must
 	 * calculate the standard hash first, as the d_op->d_hash()
@@ -2010,13 +2009,13 @@ struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name)
 	 */
 	name->hash = full_name_hash(name->name, name->len);
 	if (dir->d_flags & DCACHE_OP_HASH) {
-		if (dir->d_op->d_hash(dir, dir->d_inode, name) < 0)
-			goto out;
+		int err = dir->d_op->d_hash(dir, dir->d_inode, name);
+		if (unlikely(err < 0))
+			return ERR_PTR(err);
 	}
-	dentry = d_lookup(dir, name);
-out:
-	return dentry;
+	return d_lookup(dir, name);
 }
+EXPORT_SYMBOL(d_hash_and_lookup);
 
 /**
  * d_validate - verify dentry provided from insecure source (deprecated)
@@ -2995,7 +2994,7 @@ ino_t find_inode_number(struct dentry *dir, struct qstr *name)
 	ino_t ino = 0;
 
 	dentry = d_hash_and_lookup(dir, name);
-	if (dentry) {
+	if (!IS_ERR_OR_NULL(dentry)) {
 		if (dentry->d_inode)
 			ino = dentry->d_inode->i_ino;
 		dput(dentry);

fs/ncpfs/dir.c

@@ -593,14 +593,10 @@ ncp_fill_cache(struct file *filp, void *dirent, filldir_t filldir,
 		return 1; /* I'm not sure */
 
 	qname.name = __name;
-	qname.hash = full_name_hash(qname.name, qname.len);
 
-	if (dentry->d_op && dentry->d_op->d_hash)
-		if (dentry->d_op->d_hash(dentry, dentry->d_inode, &qname) != 0)
+	newdent = d_hash_and_lookup(dentry, &qname);
+	if (unlikely(IS_ERR(newdent)))
 		goto end_advance;
-
-	newdent = d_lookup(dentry, &qname);
-
 	if (!newdent) {
 		newdent = d_alloc(dentry, &qname);
 		if (!newdent)

fs/proc/base.c

@@ -2618,6 +2618,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
 
 	name.name = buf;
 	name.len = snprintf(buf, sizeof(buf), "%d", pid);
+	/* no ->d_hash() rejects on procfs */
 	dentry = d_hash_and_lookup(mnt->mnt_root, &name);
 	if (dentry) {
 		shrink_dcache_parent(dentry);