Share zfs_fsync, zfs_read, zfs_write, et al between Linux and FreeBSD

The zfs_fsync, zfs_read, and zfs_write function are almost identical
between Linux and FreeBSD.  With a little refactoring they can be
moved to the common code which is what is done by this commit.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #11078

include/os/linux/zfs/sys/Makefile.am

@@ -21,7 +21,7 @@ KERNEL_H = \
 	zfs_ctldir.h \
 	zfs_dir.h \
 	zfs_vfsops_os.h \
-	zfs_vnops.h \
+	zfs_vnops_os.h \
 	zfs_znode_impl.h \
 	zpl.h
 

include/os/linux/zfs/sys/policy.h

@@ -35,6 +35,8 @@
 #include <sys/xvattr.h>
 #include <sys/zpl.h>
 
+struct znode;
+
 int secpolicy_nfs(const cred_t *);
 int secpolicy_sys_config(const cred_t *, boolean_t);
 int secpolicy_vnode_access2(const cred_t *, struct inode *,
@@ -44,7 +46,7 @@ int secpolicy_vnode_chown(const cred_t *, uid_t);
 int secpolicy_vnode_create_gid(const cred_t *);
 int secpolicy_vnode_remove(const cred_t *);
 int secpolicy_vnode_setdac(const cred_t *, uid_t);
-int secpolicy_vnode_setid_retain(const cred_t *, boolean_t);
+int secpolicy_vnode_setid_retain(struct znode *, const cred_t *, boolean_t);
 int secpolicy_vnode_setids_setgids(const cred_t *, gid_t);
 int secpolicy_zinject(const cred_t *);
 int secpolicy_zfs(const cred_t *);

include/os/linux/zfs/sys/zfs_vnops_os.h

@@ -22,8 +22,8 @@
  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
-#ifndef	_SYS_FS_ZFS_VNOPS_H
-#define	_SYS_FS_ZFS_VNOPS_H
+#ifndef	_SYS_FS_ZFS_VNOPS_OS_H
+#define	_SYS_FS_ZFS_VNOPS_OS_H
 
 #include <sys/vnode.h>
 #include <sys/xvattr.h>
@@ -41,8 +41,6 @@ extern "C" {
 extern int zfs_open(struct inode *ip, int mode, int flag, cred_t *cr);
 extern int zfs_close(struct inode *ip, int flag, cred_t *cr);
 extern int zfs_holey(struct inode *ip, int cmd, loff_t *off);
-extern int zfs_read(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr);
-extern int zfs_write(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr);
 extern int zfs_write_simple(znode_t *zp, const void *data, size_t len,
     loff_t pos, size_t *resid);
 extern int zfs_access(struct inode *ip, int mode, int flag, cred_t *cr);
@@ -58,7 +56,6 @@ extern int zfs_mkdir(znode_t *dzp, char *dirname, vattr_t *vap,
 extern int zfs_rmdir(znode_t *dzp, char *name, znode_t *cwd,
     cred_t *cr, int flags);
 extern int zfs_readdir(struct inode *ip, zpl_dir_context_t *ctx, cred_t *cr);
-extern int zfs_fsync(znode_t *zp, int syncflag, cred_t *cr);
 extern int zfs_getattr_fast(struct inode *ip, struct kstat *sp);
 extern int zfs_setattr(znode_t *zp, vattr_t *vap, int flag, cred_t *cr);
 extern int zfs_rename(znode_t *sdzp, char *snm, znode_t *tdzp,
@@ -72,10 +69,6 @@ extern void zfs_inactive(struct inode *ip);
 extern int zfs_space(znode_t *zp, int cmd, flock64_t *bfp, int flag,
     offset_t offset, cred_t *cr);
 extern int zfs_fid(struct inode *ip, fid_t *fidp);
-extern int zfs_getsecattr(struct inode *ip, vsecattr_t *vsecp, int flag,
-    cred_t *cr);
-extern int zfs_setsecattr(znode_t *zp, vsecattr_t *vsecp, int flag,
-    cred_t *cr);
 extern int zfs_getpage(struct inode *ip, struct page *pl[], int nr_pages);
 extern int zfs_putpage(struct inode *ip, struct page *pp,
     struct writeback_control *wbc);

include/os/linux/zfs/sys/zfs_znode_impl.h

@@ -68,6 +68,10 @@ extern "C" {
 #define	Z_ISCHR(type) S_ISCHR(type)
 #define	Z_ISLNK(type) S_ISLNK(type)
 #define	Z_ISDEV(type)	(S_ISCHR(type) || S_ISBLK(type) || S_ISFIFO(type))
+#define	Z_ISDIR(type)	S_ISDIR(type)
+
+#define	zn_has_cached_data(zp)	((zp)->z_is_mapped)
+#define	zn_rlimit_fsize(zp, uio, td)	(0)
 
 #define	zhold(zp)	igrab(ZTOI((zp)))
 #define	zrele(zp)	iput(ZTOI((zp)))
@@ -147,6 +151,8 @@ do {						\
 } while (0)
 #endif /* HAVE_INODE_TIMESPEC64_TIMES */
 
+#define	ZFS_ACCESSTIME_STAMP(zfsvfs, zp)
+
 struct znode;
 
 extern int	zfs_sync(struct super_block *, int, cred_t *);