Add Hooks for Linux File Operations

The Linux specific file operations have all been located in the
file zpl_file.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.

This first zpl_* commit also includes a common zpl.h header with
minimal entries to register the Linux specific hooks.  In also
adds all the new zpl_* file to the Makefile.in.  This is not a
standalone commit, you required the following zpl_* commits.

module/zfs/Makefile.in

@@ -83,5 +83,9 @@ $(MODULE)-objs += @top_srcdir@/module/zfs/zio_checksum.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/zio_compress.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/zio_inject.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/zle.o
+$(MODULE)-objs += @top_srcdir@/module/zfs/zpl_file.o
+$(MODULE)-objs += @top_srcdir@/module/zfs/zpl_inode.o
+$(MODULE)-objs += @top_srcdir@/module/zfs/zpl_super.o
+$(MODULE)-objs += @top_srcdir@/module/zfs/zpl_xattr.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/zrlock.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/zvol.o

module/zfs/zpl_file.c

@@ -0,0 +1,173 @@
+/*
+ * 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 int
+zpl_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+	struct dentry *dentry = filp->f_path.dentry;
+	cred_t *cr;
+	int error;
+
+	cr = (cred_t *)get_current_cred();
+	error = -zfs_readdir(dentry->d_inode, dirent, filldir,
+	    &filp->f_pos, cr);
+	put_cred(cr);
+	ASSERT3S(error, <=, 0);
+
+	return (error);
+}
+
+static int
+zpl_fsync(struct file *filp, struct dentry *dentry, int datasync)
+{
+	cred_t *cr;
+	int error;
+
+	cr = (cred_t *)get_current_cred();
+	error = -zfs_fsync(filp->f_path.dentry->d_inode, datasync, cr);
+	put_cred(cr);
+	ASSERT3S(error, <=, 0);
+
+	return (error);
+}
+
+ssize_t
+zpl_read_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
+     uio_seg_t segment, int flags, cred_t *cr)
+{
+	int error;
+	struct iovec iov;
+	uio_t uio;
+
+	iov.iov_base = (void *)buf;
+	iov.iov_len = len;
+
+	uio.uio_iov = &iov;
+	uio.uio_resid = len;
+	uio.uio_iovcnt = 1;
+	uio.uio_loffset = pos;
+	uio.uio_limit = MAXOFFSET_T;
+	uio.uio_segflg = segment;
+
+	error = -zfs_read(ip, &uio, flags, cr);
+	if (error < 0)
+		return (error);
+
+	return (len - uio.uio_resid);
+}
+
+static ssize_t
+zpl_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
+{
+	cred_t *cr;
+	ssize_t read;
+
+	cr = (cred_t *)get_current_cred();
+	read = zpl_read_common(filp->f_mapping->host, buf, len, *ppos,
+	    UIO_USERSPACE, filp->f_flags, cr);
+	put_cred(cr);
+
+	if (read < 0)
+		return (read);
+
+	*ppos += read;
+	return (read);
+}
+
+ssize_t
+zpl_write_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
+    uio_seg_t segment, int flags, cred_t *cr)
+{
+	int error;
+	struct iovec iov;
+	uio_t uio;
+
+	iov.iov_base = (void *)buf;
+	iov.iov_len = len;
+
+	uio.uio_iov = &iov;
+	uio.uio_resid = len,
+	uio.uio_iovcnt = 1;
+	uio.uio_loffset = pos;
+	uio.uio_limit = MAXOFFSET_T;
+	uio.uio_segflg = segment;
+
+	error = -zfs_write(ip, &uio, flags, cr);
+	if (error < 0)
+		return (error);
+
+	return (len - uio.uio_resid);
+}
+
+static ssize_t
+zpl_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
+{
+	cred_t *cr;
+	ssize_t wrote;
+
+	cr = (cred_t *)get_current_cred();
+	wrote = zpl_write_common(filp->f_mapping->host, buf, len, *ppos,
+	    UIO_USERSPACE, filp->f_flags, cr);
+	put_cred(cr);
+
+	if (wrote < 0)
+		return (wrote);
+
+	*ppos += wrote;
+	return (wrote);
+}
+
+const struct address_space_operations zpl_address_space_operations = {
+#if 0
+	.readpage	= zpl_readpage,
+	.writepage	= zpl_writepage,
+	.direct_IO	= zpl_direct_IO,
+#endif
+};
+
+const struct file_operations zpl_file_operations = {
+	.open		= generic_file_open,
+	.llseek		= generic_file_llseek,
+	.read		= zpl_read,	/* do_sync_read */
+	.write		= zpl_write,	/* do_sync_write */
+	.readdir	= zpl_readdir,
+	.mmap		= generic_file_mmap,
+	.fsync		= zpl_fsync,
+	.aio_read	= NULL,		/* generic_file_aio_read */
+	.aio_write	= NULL,		/* generic_file_aio_write */
+};
+
+const struct file_operations zpl_dir_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.readdir	= zpl_readdir,
+	.fsync		= zpl_fsync,
+};