Add Hooks for Linux Super Block Operations

The Linux specific super block operations have all been located in the
file zpl_super.c.  These functions primarily rely on the reworked
zfs_* functions to do their job.  They are also responsible for
converting the possible Solaris style error codes to negative
Linux errors.

module/zfs/zpl_super.c

@@ -0,0 +1,168 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2011, Lawrence Livermore National Security, LLC.
+ */
+
+
+#include <sys/zfs_vfsops.h>
+#include <sys/zfs_vnops.h>
+#include <sys/zfs_znode.h>
+#include <sys/zpl.h>
+
+
+static struct inode *
+zpl_inode_alloc(struct super_block *sb)
+{
+	struct inode *ip;
+
+	VERIFY3S(zfs_inode_alloc(sb, &ip), ==, 0);
+	ip->i_version = 1;
+
+	return (ip);
+}
+
+static void
+zpl_inode_destroy(struct inode *ip)
+{
+        ASSERT(atomic_read(&ip->i_count) == 0);
+	zfs_inode_destroy(ip);
+}
+
+static void
+zpl_inode_delete(struct inode *ip)
+{
+	loff_t oldsize = i_size_read(ip);
+
+	i_size_write(ip, 0);
+	truncate_pagecache(ip, oldsize, 0);
+	clear_inode(ip);
+}
+
+static void
+zpl_evict_inode(struct inode *ip)
+{
+	zfs_inactive(ip);
+}
+
+static void
+zpl_put_super(struct super_block *sb)
+{
+	int error;
+
+	error = -zfs_umount(sb);
+	ASSERT3S(error, <=, 0);
+}
+
+static int
+zpl_statfs(struct dentry *dentry, struct kstatfs *statp)
+{
+	int error;
+
+	error = -zfs_statvfs(dentry, statp);
+	ASSERT3S(error, <=, 0);
+
+	return (error);
+}
+
+static int
+zpl_show_options(struct seq_file *seq, struct vfsmount *vfsp)
+{
+	struct super_block *sb = vfsp->mnt_sb;
+	zfs_sb_t *zsb = sb->s_fs_info;
+
+	/*
+	 * The Linux VFS automatically handles the following flags:
+	 * MNT_NOSUID, MNT_NODEV, MNT_NOEXEC, MNT_NOATIME, MNT_READONLY
+	 */
+
+	if (zsb->z_flags & ZSB_XATTR_USER)
+		seq_printf(seq, ",%s", "xattr");
+
+	return (0);
+}
+
+static int
+zpl_fill_super(struct super_block *sb, void *data, int silent)
+{
+	int error;
+
+	error = -zfs_domount(sb, data, silent);
+	ASSERT3S(error, <=, 0);
+
+	return (error);
+}
+
+static int
+zpl_get_sb(struct file_system_type *fs_type, int flags,
+    const char *osname, void *data, struct vfsmount *mnt)
+{
+	zpl_mount_data_t zmd = { osname, data, mnt };
+
+	return get_sb_nodev(fs_type, flags, &zmd, zpl_fill_super, mnt);
+}
+
+static void
+zpl_kill_sb(struct super_block *sb)
+{
+#ifdef HAVE_SNAPSHOT
+	zfs_sb_t *zsb = sb->s_fs_info;
+
+	if (zsb && dmu_objset_is_snapshot(zsb->z_os))
+		zfs_snap_destroy(zsb);
+#endif /* HAVE_SNAPSHOT */
+
+	kill_anon_super(sb);
+}
+
+const struct super_operations zpl_super_operations = {
+	.alloc_inode	= zpl_inode_alloc,
+	.destroy_inode	= zpl_inode_destroy,
+	.delete_inode	= zpl_inode_delete,
+	.dirty_inode	= NULL,
+	.write_inode	= NULL,
+	.drop_inode	= NULL,
+	.clear_inode	= zpl_evict_inode,
+	.put_super	= zpl_put_super,
+	.write_super	= NULL,
+	.sync_fs	= NULL,
+	.freeze_fs	= NULL,
+	.unfreeze_fs	= NULL,
+	.statfs		= zpl_statfs,
+	.remount_fs	= NULL,
+	.show_options	= zpl_show_options,
+	.show_stats	= NULL,
+};
+
+#if 0
+const struct export_operations zpl_export_operations = {
+	.fh_to_dentry	= NULL,
+	.fh_to_parent	= NULL,
+	.get_parent	= NULL,
+};
+#endif
+
+struct file_system_type zpl_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= ZFS_DRIVER,
+	.get_sb		= zpl_get_sb,
+	.kill_sb	= zpl_kill_sb,
+};