hfsplus: clean up hfsplus_iget

Add a new hfsplus_system_read_inode for reading the special system inodes
and streamline the fastpath iget code.
Signed-off-by: Christoph Hellwig <hch@tuxera.com>

fs/hfsplus/super.c

@@ -20,12 +20,42 @@ static void hfsplus_destroy_inode(struct inode *inode);
 
 #include "hfsplus_fs.h"
 
+static int hfsplus_system_read_inode(struct inode *inode)
+{
+	struct hfsplus_vh *vhdr = HFSPLUS_SB(inode->i_sb)->s_vhdr;
+
+	switch (inode->i_ino) {
+	case HFSPLUS_EXT_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->ext_file);
+		inode->i_mapping->a_ops = &hfsplus_btree_aops;
+		break;
+	case HFSPLUS_CAT_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->cat_file);
+		inode->i_mapping->a_ops = &hfsplus_btree_aops;
+		break;
+	case HFSPLUS_ALLOC_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->alloc_file);
+		inode->i_mapping->a_ops = &hfsplus_aops;
+		break;
+	case HFSPLUS_START_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->start_file);
+		break;
+	case HFSPLUS_ATTR_CNID:
+		hfsplus_inode_read_fork(inode, &vhdr->attr_file);
+		inode->i_mapping->a_ops = &hfsplus_btree_aops;
+		break;
+	default:
+		return -EIO;
+	}
+
+	return 0;
+}
+
 struct inode *hfsplus_iget(struct super_block *sb, unsigned long ino)
 {
 	struct hfs_find_data fd;
-	struct hfsplus_vh *vhdr;
 	struct inode *inode;
-	long err = -EIO;
+	int err;
 
 	inode = iget_locked(sb, ino);
 	if (!inode)
@@ -39,51 +69,24 @@ struct inode *hfsplus_iget(struct super_block *sb, unsigned long ino)
 	HFSPLUS_I(inode)->rsrc_inode = NULL;
 	atomic_set(&HFSPLUS_I(inode)->opencnt, 0);
 
-	if (inode->i_ino >= HFSPLUS_FIRSTUSER_CNID) {
-	read_inode:
+	if (inode->i_ino >= HFSPLUS_FIRSTUSER_CNID ||
+	    inode->i_ino == HFSPLUS_ROOT_CNID) {
 		hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
 		err = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
 		if (!err)
 			err = hfsplus_cat_read_inode(inode, &fd);
 		hfs_find_exit(&fd);
-		if (err)
-			goto bad_inode;
-		goto done;
+	} else {
+		err = hfsplus_system_read_inode(inode);
 	}
-	vhdr = HFSPLUS_SB(inode->i_sb)->s_vhdr;
-	switch(inode->i_ino) {
-	case HFSPLUS_ROOT_CNID:
-		goto read_inode;
-	case HFSPLUS_EXT_CNID:
-		hfsplus_inode_read_fork(inode, &vhdr->ext_file);
-		inode->i_mapping->a_ops = &hfsplus_btree_aops;
-		break;
-	case HFSPLUS_CAT_CNID:
-		hfsplus_inode_read_fork(inode, &vhdr->cat_file);
-		inode->i_mapping->a_ops = &hfsplus_btree_aops;
-		break;
-	case HFSPLUS_ALLOC_CNID:
-		hfsplus_inode_read_fork(inode, &vhdr->alloc_file);
-		inode->i_mapping->a_ops = &hfsplus_aops;
-		break;
-	case HFSPLUS_START_CNID:
-		hfsplus_inode_read_fork(inode, &vhdr->start_file);
-		break;
-	case HFSPLUS_ATTR_CNID:
-		hfsplus_inode_read_fork(inode, &vhdr->attr_file);
-		inode->i_mapping->a_ops = &hfsplus_btree_aops;
-		break;
-	default:
-		goto bad_inode;
+
+	if (err) {
+		iget_failed(inode);
+		return ERR_PTR(err);
 	}
 
-done:
 	unlock_new_inode(inode);
 	return inode;
-
-bad_inode:
-	iget_failed(inode);
-	return ERR_PTR(err);
 }
 
 static int hfsplus_write_inode(struct inode *inode,