diff --git a/src/kernel/linux/v4.19/fs/exofs/BUGS b/src/kernel/linux/v4.19/fs/exofs/BUGS
new file mode 100644
index 0000000..1b2d4c6
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/BUGS
@@ -0,0 +1,3 @@
+- Out-of-space may cause a severe problem if the object (and directory entry)
+  were written, but the inode attributes failed. Then if the filesystem was
+  unmounted and mounted the kernel can get into an endless loop doing a readdir.
diff --git a/src/kernel/linux/v4.19/fs/exofs/Kbuild b/src/kernel/linux/v4.19/fs/exofs/Kbuild
new file mode 100644
index 0000000..a364fd0
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/Kbuild
@@ -0,0 +1,20 @@
+#
+# Kbuild for the EXOFS module
+#
+# Copyright (C) 2008 Panasas Inc.  All rights reserved.
+#
+# Authors:
+#   Boaz Harrosh <ooo@electrozaur.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2
+#
+# Kbuild - Gets included from the Kernels Makefile and build system
+#
+
+# ore module library
+libore-y := ore.o ore_raid.o
+obj-$(CONFIG_ORE) += libore.o
+
+exofs-y := inode.o file.o namei.o dir.o super.o sys.o
+obj-$(CONFIG_EXOFS_FS) += exofs.o
diff --git a/src/kernel/linux/v4.19/fs/exofs/Kconfig b/src/kernel/linux/v4.19/fs/exofs/Kconfig
new file mode 100644
index 0000000..86194b2
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/Kconfig
@@ -0,0 +1,13 @@
+config EXOFS_FS
+	tristate "exofs: OSD based file system support"
+	depends on SCSI_OSD_ULD
+	help
+	  EXOFS is a file system that uses an OSD storage device,
+	  as its backing storage.
+
+# Debugging-related stuff
+config EXOFS_DEBUG
+	bool "Enable debugging"
+	depends on EXOFS_FS
+	help
+	  This option enables EXOFS debug prints.
diff --git a/src/kernel/linux/v4.19/fs/exofs/Kconfig.ore b/src/kernel/linux/v4.19/fs/exofs/Kconfig.ore
new file mode 100644
index 0000000..2daf232
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/Kconfig.ore
@@ -0,0 +1,14 @@
+# ORE - Objects Raid Engine (libore.ko)
+#
+# Note ORE needs to "select ASYNC_XOR". So Not to force multiple selects
+# for every ORE user we do it like this. Any user should add itself here
+# at the "depends on EXOFS_FS || ..." with an ||. The dependencies are
+# selected here, and we default to "ON". So in effect it is like been
+# selected by any of the users.
+config ORE
+	tristate
+	depends on EXOFS_FS || PNFS_OBJLAYOUT
+	select ASYNC_XOR
+	select RAID6_PQ
+	select ASYNC_PQ
+	default SCSI_OSD_ULD
diff --git a/src/kernel/linux/v4.19/fs/exofs/common.h b/src/kernel/linux/v4.19/fs/exofs/common.h
new file mode 100644
index 0000000..7d88ef5
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/common.h
@@ -0,0 +1,262 @@
+/*
+ * common.h - Common definitions for both Kernel and user-mode utilities
+ *
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     Copyright (C) 1992, 1993, 1994, 1995
+ *     Remy Card (card@masi.ibp.fr)
+ *     Laboratoire MASI - Institut Blaise Pascal
+ *     Universite Pierre et Marie Curie (Paris VI)
+ *     from
+ *     linux/fs/minix/inode.c
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef __EXOFS_COM_H__
+#define __EXOFS_COM_H__
+
+#include <linux/types.h>
+
+#include <scsi/osd_attributes.h>
+#include <scsi/osd_initiator.h>
+#include <scsi/osd_sec.h>
+
+/****************************************************************************
+ * Object ID related defines
+ * NOTE: inode# = object ID - EXOFS_OBJ_OFF
+ ****************************************************************************/
+#define EXOFS_MIN_PID   0x10000	/* Smallest partition ID */
+#define EXOFS_OBJ_OFF	0x10000	/* offset for objects */
+#define EXOFS_SUPER_ID	0x10000	/* object ID for on-disk superblock */
+#define EXOFS_DEVTABLE_ID 0x10001 /* object ID for on-disk device table */
+#define EXOFS_ROOT_ID	0x10002	/* object ID for root directory */
+
+/* exofs Application specific page/attribute */
+/* Inode attrs */
+# define EXOFS_APAGE_FS_DATA	(OSD_APAGE_APP_DEFINED_FIRST + 3)
+# define EXOFS_ATTR_INODE_DATA	1
+# define EXOFS_ATTR_INODE_FILE_LAYOUT	2
+# define EXOFS_ATTR_INODE_DIR_LAYOUT	3
+/* Partition attrs */
+# define EXOFS_APAGE_SB_DATA	(0xF0000000U + 3)
+# define EXOFS_ATTR_SB_STATS	1
+
+/*
+ * The maximum number of files we can have is limited by the size of the
+ * inode number.  This is the largest object ID that the file system supports.
+ * Object IDs 0, 1, and 2 are always in use (see above defines).
+ */
+enum {
+	EXOFS_MAX_INO_ID = (sizeof(ino_t) * 8 == 64) ? ULLONG_MAX :
+					(1ULL << (sizeof(ino_t) * 8ULL - 1ULL)),
+	EXOFS_MAX_ID	 = (EXOFS_MAX_INO_ID - 1 - EXOFS_OBJ_OFF),
+};
+
+/****************************************************************************
+ * Misc.
+ ****************************************************************************/
+#define EXOFS_BLKSHIFT	12
+#define EXOFS_BLKSIZE	(1UL << EXOFS_BLKSHIFT)
+
+/****************************************************************************
+ * superblock-related things
+ ****************************************************************************/
+#define EXOFS_SUPER_MAGIC	0x5DF5
+
+/*
+ * The file system control block - stored in object EXOFS_SUPER_ID's data.
+ * This is where the in-memory superblock is stored on disk.
+ */
+enum {EXOFS_FSCB_VER = 1, EXOFS_DT_VER = 1};
+struct exofs_fscb {
+	__le64  s_nextid;	/* Only used after mkfs */
+	__le64  s_numfiles;	/* Only used after mkfs */
+	__le32	s_version;	/* == EXOFS_FSCB_VER */
+	__le16  s_magic;	/* Magic signature */
+	__le16  s_newfs;	/* Non-zero if this is a new fs */
+
+	/* From here on it's a static part, only written by mkexofs */
+	__le64	s_dev_table_oid;   /* Resurved, not used */
+	__le64	s_dev_table_count; /* == 0 means no dev_table */
+} __packed;
+
+/*
+ * This struct is set on the FS partition's attributes.
+ * [EXOFS_APAGE_SB_DATA, EXOFS_ATTR_SB_STATS] and is written together
+ * with the create command, to atomically persist the sb writeable information.
+ */
+struct exofs_sb_stats {
+	__le64  s_nextid;	/* Highest object ID used */
+	__le64  s_numfiles;	/* Number of files on fs */
+} __packed;
+
+/*
+ * Describes the raid used in the FS. It is part of the device table.
+ * This here is taken from the pNFS-objects definition. In exofs we
+ * use one raid policy through-out the filesystem. (NOTE: the funny
+ * alignment at beginning. We take care of it at exofs_device_table.
+ */
+struct exofs_dt_data_map {
+	__le32	cb_num_comps;
+	__le64	cb_stripe_unit;
+	__le32	cb_group_width;
+	__le32	cb_group_depth;
+	__le32	cb_mirror_cnt;
+	__le32	cb_raid_algorithm;
+} __packed;
+
+/*
+ * This is an osd device information descriptor. It is a single entry in
+ * the exofs device table. It describes an osd target lun which
+ * contains data belonging to this FS. (Same partition_id on all devices)
+ */
+struct exofs_dt_device_info {
+	__le32	systemid_len;
+	u8	systemid[OSD_SYSTEMID_LEN];
+	__le64	long_name_offset;	/* If !0 then offset-in-file */
+	__le32	osdname_len;		/* */
+	u8	osdname[44];		/* Embbeded, Usually an asci uuid */
+} __packed;
+
+/*
+ * The EXOFS device table - stored in object EXOFS_DEVTABLE_ID's data.
+ * It contains the raid used for this multy-device FS and an array of
+ * participating devices.
+ */
+struct exofs_device_table {
+	__le32				dt_version;	/* == EXOFS_DT_VER */
+	struct exofs_dt_data_map	dt_data_map;	/* Raid policy to use */
+
+	/* Resurved space For future use. Total includeing this:
+	 * (8 * sizeof(le64))
+	 */
+	__le64				__Resurved[4];
+
+	__le64				dt_num_devices;	/* Array size */
+	struct exofs_dt_device_info	dt_dev_table[];	/* Array of devices */
+} __packed;
+
+/****************************************************************************
+ * inode-related things
+ ****************************************************************************/
+#define EXOFS_IDATA		5
+
+/*
+ * The file control block - stored in an object's attributes.  This is where
+ * the in-memory inode is stored on disk.
+ */
+struct exofs_fcb {
+	__le64  i_size;			/* Size of the file */
+	__le16  i_mode;         	/* File mode */
+	__le16  i_links_count;  	/* Links count */
+	__le32  i_uid;          	/* Owner Uid */
+	__le32  i_gid;          	/* Group Id */
+	__le32  i_atime;        	/* Access time */
+	__le32  i_ctime;        	/* Creation time */
+	__le32  i_mtime;        	/* Modification time */
+	__le32  i_flags;        	/* File flags (unused for now)*/
+	__le32  i_generation;   	/* File version (for NFS) */
+	__le32  i_data[EXOFS_IDATA];	/* Short symlink names and device #s */
+};
+
+#define EXOFS_INO_ATTR_SIZE	sizeof(struct exofs_fcb)
+
+/* This is the Attribute the fcb is stored in */
+static const struct __weak osd_attr g_attr_inode_data = ATTR_DEF(
+	EXOFS_APAGE_FS_DATA,
+	EXOFS_ATTR_INODE_DATA,
+	EXOFS_INO_ATTR_SIZE);
+
+/****************************************************************************
+ * dentry-related things
+ ****************************************************************************/
+#define EXOFS_NAME_LEN	255
+
+/*
+ * The on-disk directory entry
+ */
+struct exofs_dir_entry {
+	__le64		inode_no;		/* inode number           */
+	__le16		rec_len;		/* directory entry length */
+	u8		name_len;		/* name length            */
+	u8		file_type;		/* umm...file type        */
+	char		name[EXOFS_NAME_LEN];	/* file name              */
+};
+
+enum {
+	EXOFS_FT_UNKNOWN,
+	EXOFS_FT_REG_FILE,
+	EXOFS_FT_DIR,
+	EXOFS_FT_CHRDEV,
+	EXOFS_FT_BLKDEV,
+	EXOFS_FT_FIFO,
+	EXOFS_FT_SOCK,
+	EXOFS_FT_SYMLINK,
+	EXOFS_FT_MAX
+};
+
+#define EXOFS_DIR_PAD			4
+#define EXOFS_DIR_ROUND			(EXOFS_DIR_PAD - 1)
+#define EXOFS_DIR_REC_LEN(name_len) \
+	(((name_len) + offsetof(struct exofs_dir_entry, name)  + \
+	  EXOFS_DIR_ROUND) & ~EXOFS_DIR_ROUND)
+
+/*
+ * The on-disk (optional) layout structure.
+ * sits in an EXOFS_ATTR_INODE_FILE_LAYOUT or EXOFS_ATTR_INODE_DIR_LAYOUT
+ * attribute, attached to any inode, usually to a directory.
+ */
+
+enum exofs_inode_layout_gen_functions {
+	LAYOUT_MOVING_WINDOW = 0,
+	LAYOUT_IMPLICT = 1,
+};
+
+struct exofs_on_disk_inode_layout {
+	__le16 gen_func; /* One of enum exofs_inode_layout_gen_functions */
+	__le16 pad;
+	union {
+		/* gen_func == LAYOUT_MOVING_WINDOW (default) */
+		struct exofs_layout_sliding_window {
+			__le32 num_devices; /* first n devices in global-table*/
+		} sliding_window __packed;
+
+		/* gen_func == LAYOUT_IMPLICT */
+		struct exofs_layout_implict_list {
+			struct exofs_dt_data_map data_map;
+			/* Variable array of size data_map.cb_num_comps. These
+			 * are device indexes of the devices in the global table
+			 */
+			__le32 dev_indexes[];
+		} implict __packed;
+	};
+} __packed;
+
+static inline size_t exofs_on_disk_inode_layout_size(unsigned max_devs)
+{
+	return sizeof(struct exofs_on_disk_inode_layout) +
+		max_devs * sizeof(__le32);
+}
+
+#endif /*ifndef __EXOFS_COM_H__*/
diff --git a/src/kernel/linux/v4.19/fs/exofs/dir.c b/src/kernel/linux/v4.19/fs/exofs/dir.c
new file mode 100644
index 0000000..f013867
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/dir.c
@@ -0,0 +1,661 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     Copyright (C) 1992, 1993, 1994, 1995
+ *     Remy Card (card@masi.ibp.fr)
+ *     Laboratoire MASI - Institut Blaise Pascal
+ *     Universite Pierre et Marie Curie (Paris VI)
+ *     from
+ *     linux/fs/minix/inode.c
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/iversion.h>
+#include "exofs.h"
+
+static inline unsigned exofs_chunk_size(struct inode *inode)
+{
+	return inode->i_sb->s_blocksize;
+}
+
+static inline void exofs_put_page(struct page *page)
+{
+	kunmap(page);
+	put_page(page);
+}
+
+static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
+{
+	loff_t last_byte = inode->i_size;
+
+	last_byte -= page_nr << PAGE_SHIFT;
+	if (last_byte > PAGE_SIZE)
+		last_byte = PAGE_SIZE;
+	return last_byte;
+}
+
+static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *dir = mapping->host;
+	int err = 0;
+
+	inode_inc_iversion(dir);
+
+	if (!PageUptodate(page))
+		SetPageUptodate(page);
+
+	if (pos+len > dir->i_size) {
+		i_size_write(dir, pos+len);
+		mark_inode_dirty(dir);
+	}
+	set_page_dirty(page);
+
+	if (IS_DIRSYNC(dir))
+		err = write_one_page(page);
+	else
+		unlock_page(page);
+
+	return err;
+}
+
+static bool exofs_check_page(struct page *page)
+{
+	struct inode *dir = page->mapping->host;
+	unsigned chunk_size = exofs_chunk_size(dir);
+	char *kaddr = page_address(page);
+	unsigned offs, rec_len;
+	unsigned limit = PAGE_SIZE;
+	struct exofs_dir_entry *p;
+	char *error;
+
+	/* if the page is the last one in the directory */
+	if ((dir->i_size >> PAGE_SHIFT) == page->index) {
+		limit = dir->i_size & ~PAGE_MASK;
+		if (limit & (chunk_size - 1))
+			goto Ebadsize;
+		if (!limit)
+			goto out;
+	}
+	for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) {
+		p = (struct exofs_dir_entry *)(kaddr + offs);
+		rec_len = le16_to_cpu(p->rec_len);
+
+		if (rec_len < EXOFS_DIR_REC_LEN(1))
+			goto Eshort;
+		if (rec_len & 3)
+			goto Ealign;
+		if (rec_len < EXOFS_DIR_REC_LEN(p->name_len))
+			goto Enamelen;
+		if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
+			goto Espan;
+	}
+	if (offs != limit)
+		goto Eend;
+out:
+	SetPageChecked(page);
+	return true;
+
+Ebadsize:
+	EXOFS_ERR("ERROR [exofs_check_page]: "
+		"size of directory(0x%lx) is not a multiple of chunk size\n",
+		dir->i_ino
+	);
+	goto fail;
+Eshort:
+	error = "rec_len is smaller than minimal";
+	goto bad_entry;
+Ealign:
+	error = "unaligned directory entry";
+	goto bad_entry;
+Enamelen:
+	error = "rec_len is too small for name_len";
+	goto bad_entry;
+Espan:
+	error = "directory entry across blocks";
+	goto bad_entry;
+bad_entry:
+	EXOFS_ERR(
+		"ERROR [exofs_check_page]: bad entry in directory(0x%lx): %s - "
+		"offset=%lu, inode=0x%llx, rec_len=%d, name_len=%d\n",
+		dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
+		_LLU(le64_to_cpu(p->inode_no)),
+		rec_len, p->name_len);
+	goto fail;
+Eend:
+	p = (struct exofs_dir_entry *)(kaddr + offs);
+	EXOFS_ERR("ERROR [exofs_check_page]: "
+		"entry in directory(0x%lx) spans the page boundary"
+		"offset=%lu, inode=0x%llx\n",
+		dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
+		_LLU(le64_to_cpu(p->inode_no)));
+fail:
+	SetPageError(page);
+	return false;
+}
+
+static struct page *exofs_get_page(struct inode *dir, unsigned long n)
+{
+	struct address_space *mapping = dir->i_mapping;
+	struct page *page = read_mapping_page(mapping, n, NULL);
+
+	if (!IS_ERR(page)) {
+		kmap(page);
+		if (unlikely(!PageChecked(page))) {
+			if (PageError(page) || !exofs_check_page(page))
+				goto fail;
+		}
+	}
+	return page;
+
+fail:
+	exofs_put_page(page);
+	return ERR_PTR(-EIO);
+}
+
+static inline int exofs_match(int len, const unsigned char *name,
+					struct exofs_dir_entry *de)
+{
+	if (len != de->name_len)
+		return 0;
+	if (!de->inode_no)
+		return 0;
+	return !memcmp(name, de->name, len);
+}
+
+static inline
+struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p)
+{
+	return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
+}
+
+static inline unsigned
+exofs_validate_entry(char *base, unsigned offset, unsigned mask)
+{
+	struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset);
+	struct exofs_dir_entry *p =
+			(struct exofs_dir_entry *)(base + (offset&mask));
+	while ((char *)p < (char *)de) {
+		if (p->rec_len == 0)
+			break;
+		p = exofs_next_entry(p);
+	}
+	return (char *)p - base;
+}
+
+static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = {
+	[EXOFS_FT_UNKNOWN]	= DT_UNKNOWN,
+	[EXOFS_FT_REG_FILE]	= DT_REG,
+	[EXOFS_FT_DIR]		= DT_DIR,
+	[EXOFS_FT_CHRDEV]	= DT_CHR,
+	[EXOFS_FT_BLKDEV]	= DT_BLK,
+	[EXOFS_FT_FIFO]		= DT_FIFO,
+	[EXOFS_FT_SOCK]		= DT_SOCK,
+	[EXOFS_FT_SYMLINK]	= DT_LNK,
+};
+
+#define S_SHIFT 12
+static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = {
+	[S_IFREG >> S_SHIFT]	= EXOFS_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= EXOFS_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= EXOFS_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= EXOFS_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= EXOFS_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= EXOFS_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= EXOFS_FT_SYMLINK,
+};
+
+static inline
+void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode)
+{
+	umode_t mode = inode->i_mode;
+	de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
+}
+
+static int
+exofs_readdir(struct file *file, struct dir_context *ctx)
+{
+	loff_t pos = ctx->pos;
+	struct inode *inode = file_inode(file);
+	unsigned int offset = pos & ~PAGE_MASK;
+	unsigned long n = pos >> PAGE_SHIFT;
+	unsigned long npages = dir_pages(inode);
+	unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
+	bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
+
+	if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
+		return 0;
+
+	for ( ; n < npages; n++, offset = 0) {
+		char *kaddr, *limit;
+		struct exofs_dir_entry *de;
+		struct page *page = exofs_get_page(inode, n);
+
+		if (IS_ERR(page)) {
+			EXOFS_ERR("ERROR: bad page in directory(0x%lx)\n",
+				  inode->i_ino);
+			ctx->pos += PAGE_SIZE - offset;
+			return PTR_ERR(page);
+		}
+		kaddr = page_address(page);
+		if (unlikely(need_revalidate)) {
+			if (offset) {
+				offset = exofs_validate_entry(kaddr, offset,
+								chunk_mask);
+				ctx->pos = (n<<PAGE_SHIFT) + offset;
+			}
+			file->f_version = inode_query_iversion(inode);
+			need_revalidate = false;
+		}
+		de = (struct exofs_dir_entry *)(kaddr + offset);
+		limit = kaddr + exofs_last_byte(inode, n) -
+							EXOFS_DIR_REC_LEN(1);
+		for (; (char *)de <= limit; de = exofs_next_entry(de)) {
+			if (de->rec_len == 0) {
+				EXOFS_ERR("ERROR: "
+				     "zero-length entry in directory(0x%lx)\n",
+				     inode->i_ino);
+				exofs_put_page(page);
+				return -EIO;
+			}
+			if (de->inode_no) {
+				unsigned char t;
+
+				if (de->file_type < EXOFS_FT_MAX)
+					t = exofs_filetype_table[de->file_type];
+				else
+					t = DT_UNKNOWN;
+
+				if (!dir_emit(ctx, de->name, de->name_len,
+						le64_to_cpu(de->inode_no),
+						t)) {
+					exofs_put_page(page);
+					return 0;
+				}
+			}
+			ctx->pos += le16_to_cpu(de->rec_len);
+		}
+		exofs_put_page(page);
+	}
+	return 0;
+}
+
+struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
+			struct dentry *dentry, struct page **res_page)
+{
+	const unsigned char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
+	unsigned long start, n;
+	unsigned long npages = dir_pages(dir);
+	struct page *page = NULL;
+	struct exofs_i_info *oi = exofs_i(dir);
+	struct exofs_dir_entry *de;
+
+	if (npages == 0)
+		goto out;
+
+	*res_page = NULL;
+
+	start = oi->i_dir_start_lookup;
+	if (start >= npages)
+		start = 0;
+	n = start;
+	do {
+		char *kaddr;
+		page = exofs_get_page(dir, n);
+		if (!IS_ERR(page)) {
+			kaddr = page_address(page);
+			de = (struct exofs_dir_entry *) kaddr;
+			kaddr += exofs_last_byte(dir, n) - reclen;
+			while ((char *) de <= kaddr) {
+				if (de->rec_len == 0) {
+					EXOFS_ERR("ERROR: zero-length entry in "
+						  "directory(0x%lx)\n",
+						  dir->i_ino);
+					exofs_put_page(page);
+					goto out;
+				}
+				if (exofs_match(namelen, name, de))
+					goto found;
+				de = exofs_next_entry(de);
+			}
+			exofs_put_page(page);
+		}
+		if (++n >= npages)
+			n = 0;
+	} while (n != start);
+out:
+	return NULL;
+
+found:
+	*res_page = page;
+	oi->i_dir_start_lookup = n;
+	return de;
+}
+
+struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
+{
+	struct page *page = exofs_get_page(dir, 0);
+	struct exofs_dir_entry *de = NULL;
+
+	if (!IS_ERR(page)) {
+		de = exofs_next_entry(
+				(struct exofs_dir_entry *)page_address(page));
+		*p = page;
+	}
+	return de;
+}
+
+ino_t exofs_parent_ino(struct dentry *child)
+{
+	struct page *page;
+	struct exofs_dir_entry *de;
+	ino_t ino;
+
+	de = exofs_dotdot(d_inode(child), &page);
+	if (!de)
+		return 0;
+
+	ino = le64_to_cpu(de->inode_no);
+	exofs_put_page(page);
+	return ino;
+}
+
+ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
+{
+	ino_t res = 0;
+	struct exofs_dir_entry *de;
+	struct page *page;
+
+	de = exofs_find_entry(dir, dentry, &page);
+	if (de) {
+		res = le64_to_cpu(de->inode_no);
+		exofs_put_page(page);
+	}
+	return res;
+}
+
+int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
+			struct page *page, struct inode *inode)
+{
+	loff_t pos = page_offset(page) +
+			(char *) de - (char *) page_address(page);
+	unsigned len = le16_to_cpu(de->rec_len);
+	int err;
+
+	lock_page(page);
+	err = exofs_write_begin(NULL, page->mapping, pos, len, 0, &page, NULL);
+	if (err)
+		EXOFS_ERR("exofs_set_link: exofs_write_begin FAILED => %d\n",
+			  err);
+
+	de->inode_no = cpu_to_le64(inode->i_ino);
+	exofs_set_de_type(de, inode);
+	if (likely(!err))
+		err = exofs_commit_chunk(page, pos, len);
+	exofs_put_page(page);
+	dir->i_mtime = dir->i_ctime = current_time(dir);
+	mark_inode_dirty(dir);
+	return err;
+}
+
+int exofs_add_link(struct dentry *dentry, struct inode *inode)
+{
+	struct inode *dir = d_inode(dentry->d_parent);
+	const unsigned char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	unsigned chunk_size = exofs_chunk_size(dir);
+	unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
+	unsigned short rec_len, name_len;
+	struct page *page = NULL;
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	struct exofs_dir_entry *de;
+	unsigned long npages = dir_pages(dir);
+	unsigned long n;
+	char *kaddr;
+	loff_t pos;
+	int err;
+
+	for (n = 0; n <= npages; n++) {
+		char *dir_end;
+
+		page = exofs_get_page(dir, n);
+		err = PTR_ERR(page);
+		if (IS_ERR(page))
+			goto out;
+		lock_page(page);
+		kaddr = page_address(page);
+		dir_end = kaddr + exofs_last_byte(dir, n);
+		de = (struct exofs_dir_entry *)kaddr;
+		kaddr += PAGE_SIZE - reclen;
+		while ((char *)de <= kaddr) {
+			if ((char *)de == dir_end) {
+				name_len = 0;
+				rec_len = chunk_size;
+				de->rec_len = cpu_to_le16(chunk_size);
+				de->inode_no = 0;
+				goto got_it;
+			}
+			if (de->rec_len == 0) {
+				EXOFS_ERR("ERROR: exofs_add_link: "
+				      "zero-length entry in directory(0x%lx)\n",
+				      inode->i_ino);
+				err = -EIO;
+				goto out_unlock;
+			}
+			err = -EEXIST;
+			if (exofs_match(namelen, name, de))
+				goto out_unlock;
+			name_len = EXOFS_DIR_REC_LEN(de->name_len);
+			rec_len = le16_to_cpu(de->rec_len);
+			if (!de->inode_no && rec_len >= reclen)
+				goto got_it;
+			if (rec_len >= name_len + reclen)
+				goto got_it;
+			de = (struct exofs_dir_entry *) ((char *) de + rec_len);
+		}
+		unlock_page(page);
+		exofs_put_page(page);
+	}
+
+	EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=0x%lx\n",
+		  dentry, inode->i_ino);
+	return -EINVAL;
+
+got_it:
+	pos = page_offset(page) +
+		(char *)de - (char *)page_address(page);
+	err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
+							&page, NULL);
+	if (err)
+		goto out_unlock;
+	if (de->inode_no) {
+		struct exofs_dir_entry *de1 =
+			(struct exofs_dir_entry *)((char *)de + name_len);
+		de1->rec_len = cpu_to_le16(rec_len - name_len);
+		de->rec_len = cpu_to_le16(name_len);
+		de = de1;
+	}
+	de->name_len = namelen;
+	memcpy(de->name, name, namelen);
+	de->inode_no = cpu_to_le64(inode->i_ino);
+	exofs_set_de_type(de, inode);
+	err = exofs_commit_chunk(page, pos, rec_len);
+	dir->i_mtime = dir->i_ctime = current_time(dir);
+	mark_inode_dirty(dir);
+	sbi->s_numfiles++;
+
+out_put:
+	exofs_put_page(page);
+out:
+	return err;
+out_unlock:
+	unlock_page(page);
+	goto out_put;
+}
+
+int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	char *kaddr = page_address(page);
+	unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
+	unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
+	loff_t pos;
+	struct exofs_dir_entry *pde = NULL;
+	struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
+	int err;
+
+	while (de < dir) {
+		if (de->rec_len == 0) {
+			EXOFS_ERR("ERROR: exofs_delete_entry:"
+				  "zero-length entry in directory(0x%lx)\n",
+				  inode->i_ino);
+			err = -EIO;
+			goto out;
+		}
+		pde = de;
+		de = exofs_next_entry(de);
+	}
+	if (pde)
+		from = (char *)pde - (char *)page_address(page);
+	pos = page_offset(page) + from;
+	lock_page(page);
+	err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
+							&page, NULL);
+	if (err)
+		EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILED => %d\n",
+			  err);
+	if (pde)
+		pde->rec_len = cpu_to_le16(to - from);
+	dir->inode_no = 0;
+	if (likely(!err))
+		err = exofs_commit_chunk(page, pos, to - from);
+	inode->i_ctime = inode->i_mtime = current_time(inode);
+	mark_inode_dirty(inode);
+	sbi->s_numfiles--;
+out:
+	exofs_put_page(page);
+	return err;
+}
+
+/* kept aligned on 4 bytes */
+#define THIS_DIR ".\0\0"
+#define PARENT_DIR "..\0"
+
+int exofs_make_empty(struct inode *inode, struct inode *parent)
+{
+	struct address_space *mapping = inode->i_mapping;
+	struct page *page = grab_cache_page(mapping, 0);
+	unsigned chunk_size = exofs_chunk_size(inode);
+	struct exofs_dir_entry *de;
+	int err;
+	void *kaddr;
+
+	if (!page)
+		return -ENOMEM;
+
+	err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
+							&page, NULL);
+	if (err) {
+		unlock_page(page);
+		goto fail;
+	}
+
+	kaddr = kmap_atomic(page);
+	de = (struct exofs_dir_entry *)kaddr;
+	de->name_len = 1;
+	de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
+	memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
+	de->inode_no = cpu_to_le64(inode->i_ino);
+	exofs_set_de_type(de, inode);
+
+	de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
+	de->name_len = 2;
+	de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
+	de->inode_no = cpu_to_le64(parent->i_ino);
+	memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
+	exofs_set_de_type(de, inode);
+	kunmap_atomic(kaddr);
+	err = exofs_commit_chunk(page, 0, chunk_size);
+fail:
+	put_page(page);
+	return err;
+}
+
+int exofs_empty_dir(struct inode *inode)
+{
+	struct page *page = NULL;
+	unsigned long i, npages = dir_pages(inode);
+
+	for (i = 0; i < npages; i++) {
+		char *kaddr;
+		struct exofs_dir_entry *de;
+		page = exofs_get_page(inode, i);
+
+		if (IS_ERR(page))
+			continue;
+
+		kaddr = page_address(page);
+		de = (struct exofs_dir_entry *)kaddr;
+		kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
+
+		while ((char *)de <= kaddr) {
+			if (de->rec_len == 0) {
+				EXOFS_ERR("ERROR: exofs_empty_dir: "
+					  "zero-length directory entry"
+					  "kaddr=%p, de=%p\n", kaddr, de);
+				goto not_empty;
+			}
+			if (de->inode_no != 0) {
+				/* check for . and .. */
+				if (de->name[0] != '.')
+					goto not_empty;
+				if (de->name_len > 2)
+					goto not_empty;
+				if (de->name_len < 2) {
+					if (le64_to_cpu(de->inode_no) !=
+					    inode->i_ino)
+						goto not_empty;
+				} else if (de->name[1] != '.')
+					goto not_empty;
+			}
+			de = exofs_next_entry(de);
+		}
+		exofs_put_page(page);
+	}
+	return 1;
+
+not_empty:
+	exofs_put_page(page);
+	return 0;
+}
+
+const struct file_operations exofs_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= exofs_readdir,
+};
diff --git a/src/kernel/linux/v4.19/fs/exofs/exofs.h b/src/kernel/linux/v4.19/fs/exofs/exofs.h
new file mode 100644
index 0000000..5dc3924
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/exofs.h
@@ -0,0 +1,240 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     Copyright (C) 1992, 1993, 1994, 1995
+ *     Remy Card (card@masi.ibp.fr)
+ *     Laboratoire MASI - Institut Blaise Pascal
+ *     Universite Pierre et Marie Curie (Paris VI)
+ *     from
+ *     linux/fs/minix/inode.c
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef __EXOFS_H__
+#define __EXOFS_H__
+
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/backing-dev.h>
+#include <scsi/osd_ore.h>
+
+#include "common.h"
+
+#define EXOFS_ERR(fmt, a...) printk(KERN_ERR "exofs: " fmt, ##a)
+
+#ifdef CONFIG_EXOFS_DEBUG
+#define EXOFS_DBGMSG(fmt, a...) \
+	printk(KERN_NOTICE "exofs @%s:%d: " fmt, __func__, __LINE__, ##a)
+#else
+#define EXOFS_DBGMSG(fmt, a...) \
+	do { if (0) printk(fmt, ##a); } while (0)
+#endif
+
+/* u64 has problems with printk this will cast it to unsigned long long */
+#define _LLU(x) (unsigned long long)(x)
+
+struct exofs_dev {
+	struct ore_dev ored;
+	unsigned did;
+	unsigned urilen;
+	uint8_t *uri;
+	struct kobject ed_kobj;
+};
+/*
+ * our extension to the in-memory superblock
+ */
+struct exofs_sb_info {
+	struct exofs_sb_stats s_ess;		/* Written often, pre-allocate*/
+	int		s_timeout;		/* timeout for OSD operations */
+	uint64_t	s_nextid;		/* highest object ID used     */
+	uint32_t	s_numfiles;		/* number of files on fs      */
+	spinlock_t	s_next_gen_lock;	/* spinlock for gen # update  */
+	u32		s_next_generation;	/* next gen # to use          */
+	atomic_t	s_curr_pending;		/* number of pending commands */
+
+	struct ore_layout	layout;		/* Default files layout       */
+	struct ore_comp one_comp;		/* id & cred of partition id=0*/
+	struct ore_components oc;		/* comps for the partition    */
+	struct kobject	s_kobj;			/* holds per-sbi kobject      */
+};
+
+/*
+ * our extension to the in-memory inode
+ */
+struct exofs_i_info {
+	struct inode   vfs_inode;          /* normal in-memory inode          */
+	wait_queue_head_t i_wq;            /* wait queue for inode            */
+	unsigned long  i_flags;            /* various atomic flags            */
+	uint32_t       i_data[EXOFS_IDATA];/*short symlink names and device #s*/
+	uint32_t       i_dir_start_lookup; /* which page to start lookup      */
+	uint64_t       i_commit_size;      /* the object's written length     */
+	struct ore_comp one_comp;	   /* same component for all devices  */
+	struct ore_components oc;	   /* inode view of the device table  */
+};
+
+static inline osd_id exofs_oi_objno(struct exofs_i_info *oi)
+{
+	return oi->vfs_inode.i_ino + EXOFS_OBJ_OFF;
+}
+
+/*
+ * our inode flags
+ */
+#define OBJ_2BCREATED	0	/* object will be created soon*/
+#define OBJ_CREATED	1	/* object has been created on the osd*/
+
+static inline int obj_2bcreated(struct exofs_i_info *oi)
+{
+	return test_bit(OBJ_2BCREATED, &oi->i_flags);
+}
+
+static inline void set_obj_2bcreated(struct exofs_i_info *oi)
+{
+	set_bit(OBJ_2BCREATED, &oi->i_flags);
+}
+
+static inline int obj_created(struct exofs_i_info *oi)
+{
+	return test_bit(OBJ_CREATED, &oi->i_flags);
+}
+
+static inline void set_obj_created(struct exofs_i_info *oi)
+{
+	set_bit(OBJ_CREATED, &oi->i_flags);
+}
+
+int __exofs_wait_obj_created(struct exofs_i_info *oi);
+static inline int wait_obj_created(struct exofs_i_info *oi)
+{
+	if (likely(obj_created(oi)))
+		return 0;
+
+	return __exofs_wait_obj_created(oi);
+}
+
+/*
+ * get to our inode from the vfs inode
+ */
+static inline struct exofs_i_info *exofs_i(struct inode *inode)
+{
+	return container_of(inode, struct exofs_i_info, vfs_inode);
+}
+
+/*
+ * Maximum count of links to a file
+ */
+#define EXOFS_LINK_MAX           32000
+
+/*************************
+ * function declarations *
+ *************************/
+
+/* inode.c               */
+unsigned exofs_max_io_pages(struct ore_layout *layout,
+			    unsigned expected_pages);
+int exofs_setattr(struct dentry *, struct iattr *);
+int exofs_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata);
+extern struct inode *exofs_iget(struct super_block *, unsigned long);
+struct inode *exofs_new_inode(struct inode *, umode_t);
+extern int exofs_write_inode(struct inode *, struct writeback_control *wbc);
+extern void exofs_evict_inode(struct inode *);
+
+/* dir.c:                */
+int exofs_add_link(struct dentry *, struct inode *);
+ino_t exofs_inode_by_name(struct inode *, struct dentry *);
+int exofs_delete_entry(struct exofs_dir_entry *, struct page *);
+int exofs_make_empty(struct inode *, struct inode *);
+struct exofs_dir_entry *exofs_find_entry(struct inode *, struct dentry *,
+					 struct page **);
+int exofs_empty_dir(struct inode *);
+struct exofs_dir_entry *exofs_dotdot(struct inode *, struct page **);
+ino_t exofs_parent_ino(struct dentry *child);
+int exofs_set_link(struct inode *, struct exofs_dir_entry *, struct page *,
+		    struct inode *);
+
+/* super.c               */
+void exofs_make_credential(u8 cred_a[OSD_CAP_LEN],
+			   const struct osd_obj_id *obj);
+int exofs_sbi_write_stats(struct exofs_sb_info *sbi);
+
+/* sys.c                 */
+int exofs_sysfs_init(void);
+void exofs_sysfs_uninit(void);
+int exofs_sysfs_sb_add(struct exofs_sb_info *sbi,
+		       struct exofs_dt_device_info *dt_dev);
+void exofs_sysfs_sb_del(struct exofs_sb_info *sbi);
+int exofs_sysfs_odev_add(struct exofs_dev *edev,
+			 struct exofs_sb_info *sbi);
+void exofs_sysfs_dbg_print(void);
+
+/*********************
+ * operation vectors *
+ *********************/
+/* dir.c:            */
+extern const struct file_operations exofs_dir_operations;
+
+/* file.c            */
+extern const struct inode_operations exofs_file_inode_operations;
+extern const struct file_operations exofs_file_operations;
+
+/* inode.c           */
+extern const struct address_space_operations exofs_aops;
+
+/* namei.c           */
+extern const struct inode_operations exofs_dir_inode_operations;
+extern const struct inode_operations exofs_special_inode_operations;
+
+/* exofs_init_comps will initialize an ore_components device array
+ * pointing to a single ore_comp struct, and a round-robin view
+ * of the device table.
+ * The first device of each inode is the [inode->ino % num_devices]
+ * and the rest of the devices sequentially following where the
+ * first device is after the last device.
+ * It is assumed that the global device array at @sbi is twice
+ * bigger and that the device table repeats twice.
+ * See: exofs_read_lookup_dev_table()
+ */
+static inline void exofs_init_comps(struct ore_components *oc,
+				    struct ore_comp *one_comp,
+				    struct exofs_sb_info *sbi, osd_id oid)
+{
+	unsigned dev_mod = (unsigned)oid, first_dev;
+
+	one_comp->obj.partition = sbi->one_comp.obj.partition;
+	one_comp->obj.id = oid;
+	exofs_make_credential(one_comp->cred, &one_comp->obj);
+
+	oc->first_dev = 0;
+	oc->numdevs = sbi->layout.group_width * sbi->layout.mirrors_p1 *
+							sbi->layout.group_count;
+	oc->single_comp = EC_SINGLE_COMP;
+	oc->comps = one_comp;
+
+	/* Round robin device view of the table */
+	first_dev = (dev_mod * sbi->layout.mirrors_p1) % sbi->oc.numdevs;
+	oc->ods = &sbi->oc.ods[first_dev];
+}
+
+#endif
diff --git a/src/kernel/linux/v4.19/fs/exofs/file.c b/src/kernel/linux/v4.19/fs/exofs/file.c
new file mode 100644
index 0000000..a94594e
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/file.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     Copyright (C) 1992, 1993, 1994, 1995
+ *     Remy Card (card@masi.ibp.fr)
+ *     Laboratoire MASI - Institut Blaise Pascal
+ *     Universite Pierre et Marie Curie (Paris VI)
+ *     from
+ *     linux/fs/minix/inode.c
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include "exofs.h"
+
+static int exofs_release_file(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+/* exofs_file_fsync - flush the inode to disk
+ *
+ *   Note, in exofs all metadata is written as part of inode, regardless.
+ *   The writeout is synchronous
+ */
+static int exofs_file_fsync(struct file *filp, loff_t start, loff_t end,
+			    int datasync)
+{
+	struct inode *inode = filp->f_mapping->host;
+	int ret;
+
+	ret = file_write_and_wait_range(filp, start, end);
+	if (ret)
+		return ret;
+
+	inode_lock(inode);
+	ret = sync_inode_metadata(filp->f_mapping->host, 1);
+	inode_unlock(inode);
+	return ret;
+}
+
+static int exofs_flush(struct file *file, fl_owner_t id)
+{
+	int ret = vfs_fsync(file, 0);
+	/* TODO: Flush the OSD target */
+	return ret;
+}
+
+const struct file_operations exofs_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read_iter	= generic_file_read_iter,
+	.write_iter	= generic_file_write_iter,
+	.mmap		= generic_file_mmap,
+	.open		= generic_file_open,
+	.release	= exofs_release_file,
+	.fsync		= exofs_file_fsync,
+	.flush		= exofs_flush,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
+};
+
+const struct inode_operations exofs_file_inode_operations = {
+	.setattr	= exofs_setattr,
+};
diff --git a/src/kernel/linux/v4.19/fs/exofs/inode.c b/src/kernel/linux/v4.19/fs/exofs/inode.c
new file mode 100644
index 0000000..5f81fcd
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/inode.c
@@ -0,0 +1,1514 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     Copyright (C) 1992, 1993, 1994, 1995
+ *     Remy Card (card@masi.ibp.fr)
+ *     Laboratoire MASI - Institut Blaise Pascal
+ *     Universite Pierre et Marie Curie (Paris VI)
+ *     from
+ *     linux/fs/minix/inode.c
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/slab.h>
+
+#include "exofs.h"
+
+#define EXOFS_DBGMSG2(M...) do {} while (0)
+
+unsigned exofs_max_io_pages(struct ore_layout *layout,
+			    unsigned expected_pages)
+{
+	unsigned pages = min_t(unsigned, expected_pages,
+			       layout->max_io_length / PAGE_SIZE);
+
+	return pages;
+}
+
+struct page_collect {
+	struct exofs_sb_info *sbi;
+	struct inode *inode;
+	unsigned expected_pages;
+	struct ore_io_state *ios;
+
+	struct page **pages;
+	unsigned alloc_pages;
+	unsigned nr_pages;
+	unsigned long length;
+	loff_t pg_first; /* keep 64bit also in 32-arches */
+	bool read_4_write; /* This means two things: that the read is sync
+			    * And the pages should not be unlocked.
+			    */
+	struct page *that_locked_page;
+};
+
+static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
+		       struct inode *inode)
+{
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+
+	pcol->sbi = sbi;
+	pcol->inode = inode;
+	pcol->expected_pages = expected_pages;
+
+	pcol->ios = NULL;
+	pcol->pages = NULL;
+	pcol->alloc_pages = 0;
+	pcol->nr_pages = 0;
+	pcol->length = 0;
+	pcol->pg_first = -1;
+	pcol->read_4_write = false;
+	pcol->that_locked_page = NULL;
+}
+
+static void _pcol_reset(struct page_collect *pcol)
+{
+	pcol->expected_pages -= min(pcol->nr_pages, pcol->expected_pages);
+
+	pcol->pages = NULL;
+	pcol->alloc_pages = 0;
+	pcol->nr_pages = 0;
+	pcol->length = 0;
+	pcol->pg_first = -1;
+	pcol->ios = NULL;
+	pcol->that_locked_page = NULL;
+
+	/* this is probably the end of the loop but in writes
+	 * it might not end here. don't be left with nothing
+	 */
+	if (!pcol->expected_pages)
+		pcol->expected_pages =
+				exofs_max_io_pages(&pcol->sbi->layout, ~0);
+}
+
+static int pcol_try_alloc(struct page_collect *pcol)
+{
+	unsigned pages;
+
+	/* TODO: easily support bio chaining */
+	pages =  exofs_max_io_pages(&pcol->sbi->layout, pcol->expected_pages);
+
+	for (; pages; pages >>= 1) {
+		pcol->pages = kmalloc_array(pages, sizeof(struct page *),
+					    GFP_KERNEL);
+		if (likely(pcol->pages)) {
+			pcol->alloc_pages = pages;
+			return 0;
+		}
+	}
+
+	EXOFS_ERR("Failed to kmalloc expected_pages=%u\n",
+		  pcol->expected_pages);
+	return -ENOMEM;
+}
+
+static void pcol_free(struct page_collect *pcol)
+{
+	kfree(pcol->pages);
+	pcol->pages = NULL;
+
+	if (pcol->ios) {
+		ore_put_io_state(pcol->ios);
+		pcol->ios = NULL;
+	}
+}
+
+static int pcol_add_page(struct page_collect *pcol, struct page *page,
+			 unsigned len)
+{
+	if (unlikely(pcol->nr_pages >= pcol->alloc_pages))
+		return -ENOMEM;
+
+	pcol->pages[pcol->nr_pages++] = page;
+	pcol->length += len;
+	return 0;
+}
+
+enum {PAGE_WAS_NOT_IN_IO = 17};
+static int update_read_page(struct page *page, int ret)
+{
+	switch (ret) {
+	case 0:
+		/* Everything is OK */
+		SetPageUptodate(page);
+		if (PageError(page))
+			ClearPageError(page);
+		break;
+	case -EFAULT:
+		/* In this case we were trying to read something that wasn't on
+		 * disk yet - return a page full of zeroes.  This should be OK,
+		 * because the object should be empty (if there was a write
+		 * before this read, the read would be waiting with the page
+		 * locked */
+		clear_highpage(page);
+
+		SetPageUptodate(page);
+		if (PageError(page))
+			ClearPageError(page);
+		EXOFS_DBGMSG("recovered read error\n");
+		/* fall through */
+	case PAGE_WAS_NOT_IN_IO:
+		ret = 0; /* recovered error */
+		break;
+	default:
+		SetPageError(page);
+	}
+	return ret;
+}
+
+static void update_write_page(struct page *page, int ret)
+{
+	if (unlikely(ret == PAGE_WAS_NOT_IN_IO))
+		return; /* don't pass start don't collect $200 */
+
+	if (ret) {
+		mapping_set_error(page->mapping, ret);
+		SetPageError(page);
+	}
+	end_page_writeback(page);
+}
+
+/* Called at the end of reads, to optionally unlock pages and update their
+ * status.
+ */
+static int __readpages_done(struct page_collect *pcol)
+{
+	int i;
+	u64 good_bytes;
+	u64 length = 0;
+	int ret = ore_check_io(pcol->ios, NULL);
+
+	if (likely(!ret)) {
+		good_bytes = pcol->length;
+		ret = PAGE_WAS_NOT_IN_IO;
+	} else {
+		good_bytes = 0;
+	}
+
+	EXOFS_DBGMSG2("readpages_done(0x%lx) good_bytes=0x%llx"
+		     " length=0x%lx nr_pages=%u\n",
+		     pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
+		     pcol->nr_pages);
+
+	for (i = 0; i < pcol->nr_pages; i++) {
+		struct page *page = pcol->pages[i];
+		struct inode *inode = page->mapping->host;
+		int page_stat;
+
+		if (inode != pcol->inode)
+			continue; /* osd might add more pages at end */
+
+		if (likely(length < good_bytes))
+			page_stat = 0;
+		else
+			page_stat = ret;
+
+		EXOFS_DBGMSG2("    readpages_done(0x%lx, 0x%lx) %s\n",
+			  inode->i_ino, page->index,
+			  page_stat ? "bad_bytes" : "good_bytes");
+
+		ret = update_read_page(page, page_stat);
+		if (!pcol->read_4_write)
+			unlock_page(page);
+		length += PAGE_SIZE;
+	}
+
+	pcol_free(pcol);
+	EXOFS_DBGMSG2("readpages_done END\n");
+	return ret;
+}
+
+/* callback of async reads */
+static void readpages_done(struct ore_io_state *ios, void *p)
+{
+	struct page_collect *pcol = p;
+
+	__readpages_done(pcol);
+	atomic_dec(&pcol->sbi->s_curr_pending);
+	kfree(pcol);
+}
+
+static void _unlock_pcol_pages(struct page_collect *pcol, int ret, int rw)
+{
+	int i;
+
+	for (i = 0; i < pcol->nr_pages; i++) {
+		struct page *page = pcol->pages[i];
+
+		if (rw == READ)
+			update_read_page(page, ret);
+		else
+			update_write_page(page, ret);
+
+		unlock_page(page);
+	}
+}
+
+static int _maybe_not_all_in_one_io(struct ore_io_state *ios,
+	struct page_collect *pcol_src, struct page_collect *pcol)
+{
+	/* length was wrong or offset was not page aligned */
+	BUG_ON(pcol_src->nr_pages < ios->nr_pages);
+
+	if (pcol_src->nr_pages > ios->nr_pages) {
+		struct page **src_page;
+		unsigned pages_less = pcol_src->nr_pages - ios->nr_pages;
+		unsigned long len_less = pcol_src->length - ios->length;
+		unsigned i;
+		int ret;
+
+		/* This IO was trimmed */
+		pcol_src->nr_pages = ios->nr_pages;
+		pcol_src->length = ios->length;
+
+		/* Left over pages are passed to the next io */
+		pcol->expected_pages += pages_less;
+		pcol->nr_pages = pages_less;
+		pcol->length = len_less;
+		src_page = pcol_src->pages + pcol_src->nr_pages;
+		pcol->pg_first = (*src_page)->index;
+
+		ret = pcol_try_alloc(pcol);
+		if (unlikely(ret))
+			return ret;
+
+		for (i = 0; i < pages_less; ++i)
+			pcol->pages[i] = *src_page++;
+
+		EXOFS_DBGMSG("Length was adjusted nr_pages=0x%x "
+			"pages_less=0x%x expected_pages=0x%x "
+			"next_offset=0x%llx next_len=0x%lx\n",
+			pcol_src->nr_pages, pages_less, pcol->expected_pages,
+			pcol->pg_first * PAGE_SIZE, pcol->length);
+	}
+	return 0;
+}
+
+static int read_exec(struct page_collect *pcol)
+{
+	struct exofs_i_info *oi = exofs_i(pcol->inode);
+	struct ore_io_state *ios;
+	struct page_collect *pcol_copy = NULL;
+	int ret;
+
+	if (!pcol->pages)
+		return 0;
+
+	if (!pcol->ios) {
+		int ret = ore_get_rw_state(&pcol->sbi->layout, &oi->oc, true,
+					     pcol->pg_first << PAGE_SHIFT,
+					     pcol->length, &pcol->ios);
+
+		if (ret)
+			return ret;
+	}
+
+	ios = pcol->ios;
+	ios->pages = pcol->pages;
+
+	if (pcol->read_4_write) {
+		ore_read(pcol->ios);
+		return __readpages_done(pcol);
+	}
+
+	pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
+	if (!pcol_copy) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	*pcol_copy = *pcol;
+	ios->done = readpages_done;
+	ios->private = pcol_copy;
+
+	/* pages ownership was passed to pcol_copy */
+	_pcol_reset(pcol);
+
+	ret = _maybe_not_all_in_one_io(ios, pcol_copy, pcol);
+	if (unlikely(ret))
+		goto err;
+
+	EXOFS_DBGMSG2("read_exec(0x%lx) offset=0x%llx length=0x%llx\n",
+		pcol->inode->i_ino, _LLU(ios->offset), _LLU(ios->length));
+
+	ret = ore_read(ios);
+	if (unlikely(ret))
+		goto err;
+
+	atomic_inc(&pcol->sbi->s_curr_pending);
+
+	return 0;
+
+err:
+	if (!pcol_copy) /* Failed before ownership transfer */
+		pcol_copy = pcol;
+	_unlock_pcol_pages(pcol_copy, ret, READ);
+	pcol_free(pcol_copy);
+	kfree(pcol_copy);
+
+	return ret;
+}
+
+/* readpage_strip is called either directly from readpage() or by the VFS from
+ * within read_cache_pages(), to add one more page to be read. It will try to
+ * collect as many contiguous pages as posible. If a discontinuity is
+ * encountered, or it runs out of resources, it will submit the previous segment
+ * and will start a new collection. Eventually caller must submit the last
+ * segment if present.
+ */
+static int readpage_strip(void *data, struct page *page)
+{
+	struct page_collect *pcol = data;
+	struct inode *inode = pcol->inode;
+	struct exofs_i_info *oi = exofs_i(inode);
+	loff_t i_size = i_size_read(inode);
+	pgoff_t end_index = i_size >> PAGE_SHIFT;
+	size_t len;
+	int ret;
+
+	BUG_ON(!PageLocked(page));
+
+	/* FIXME: Just for debugging, will be removed */
+	if (PageUptodate(page))
+		EXOFS_ERR("PageUptodate(0x%lx, 0x%lx)\n", pcol->inode->i_ino,
+			  page->index);
+
+	pcol->that_locked_page = page;
+
+	if (page->index < end_index)
+		len = PAGE_SIZE;
+	else if (page->index == end_index)
+		len = i_size & ~PAGE_MASK;
+	else
+		len = 0;
+
+	if (!len || !obj_created(oi)) {
+		/* this will be out of bounds, or doesn't exist yet.
+		 * Current page is cleared and the request is split
+		 */
+		clear_highpage(page);
+
+		SetPageUptodate(page);
+		if (PageError(page))
+			ClearPageError(page);
+
+		if (!pcol->read_4_write)
+			unlock_page(page);
+		EXOFS_DBGMSG("readpage_strip(0x%lx) empty page len=%zx "
+			     "read_4_write=%d index=0x%lx end_index=0x%lx "
+			     "splitting\n", inode->i_ino, len,
+			     pcol->read_4_write, page->index, end_index);
+
+		return read_exec(pcol);
+	}
+
+try_again:
+
+	if (unlikely(pcol->pg_first == -1)) {
+		pcol->pg_first = page->index;
+	} else if (unlikely((pcol->pg_first + pcol->nr_pages) !=
+		   page->index)) {
+		/* Discontinuity detected, split the request */
+		ret = read_exec(pcol);
+		if (unlikely(ret))
+			goto fail;
+		goto try_again;
+	}
+
+	if (!pcol->pages) {
+		ret = pcol_try_alloc(pcol);
+		if (unlikely(ret))
+			goto fail;
+	}
+
+	if (len != PAGE_SIZE)
+		zero_user(page, len, PAGE_SIZE - len);
+
+	EXOFS_DBGMSG2("    readpage_strip(0x%lx, 0x%lx) len=0x%zx\n",
+		     inode->i_ino, page->index, len);
+
+	ret = pcol_add_page(pcol, page, len);
+	if (ret) {
+		EXOFS_DBGMSG2("Failed pcol_add_page pages[i]=%p "
+			  "this_len=0x%zx nr_pages=%u length=0x%lx\n",
+			  page, len, pcol->nr_pages, pcol->length);
+
+		/* split the request, and start again with current page */
+		ret = read_exec(pcol);
+		if (unlikely(ret))
+			goto fail;
+
+		goto try_again;
+	}
+
+	return 0;
+
+fail:
+	/* SetPageError(page); ??? */
+	unlock_page(page);
+	return ret;
+}
+
+static int exofs_readpages(struct file *file, struct address_space *mapping,
+			   struct list_head *pages, unsigned nr_pages)
+{
+	struct page_collect pcol;
+	int ret;
+
+	_pcol_init(&pcol, nr_pages, mapping->host);
+
+	ret = read_cache_pages(mapping, pages, readpage_strip, &pcol);
+	if (ret) {
+		EXOFS_ERR("read_cache_pages => %d\n", ret);
+		return ret;
+	}
+
+	ret = read_exec(&pcol);
+	if (unlikely(ret))
+		return ret;
+
+	return read_exec(&pcol);
+}
+
+static int _readpage(struct page *page, bool read_4_write)
+{
+	struct page_collect pcol;
+	int ret;
+
+	_pcol_init(&pcol, 1, page->mapping->host);
+
+	pcol.read_4_write = read_4_write;
+	ret = readpage_strip(&pcol, page);
+	if (ret) {
+		EXOFS_ERR("_readpage => %d\n", ret);
+		return ret;
+	}
+
+	return read_exec(&pcol);
+}
+
+/*
+ * We don't need the file
+ */
+static int exofs_readpage(struct file *file, struct page *page)
+{
+	return _readpage(page, false);
+}
+
+/* Callback for osd_write. All writes are asynchronous */
+static void writepages_done(struct ore_io_state *ios, void *p)
+{
+	struct page_collect *pcol = p;
+	int i;
+	u64  good_bytes;
+	u64  length = 0;
+	int ret = ore_check_io(ios, NULL);
+
+	atomic_dec(&pcol->sbi->s_curr_pending);
+
+	if (likely(!ret)) {
+		good_bytes = pcol->length;
+		ret = PAGE_WAS_NOT_IN_IO;
+	} else {
+		good_bytes = 0;
+	}
+
+	EXOFS_DBGMSG2("writepages_done(0x%lx) good_bytes=0x%llx"
+		     " length=0x%lx nr_pages=%u\n",
+		     pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
+		     pcol->nr_pages);
+
+	for (i = 0; i < pcol->nr_pages; i++) {
+		struct page *page = pcol->pages[i];
+		struct inode *inode = page->mapping->host;
+		int page_stat;
+
+		if (inode != pcol->inode)
+			continue; /* osd might add more pages to a bio */
+
+		if (likely(length < good_bytes))
+			page_stat = 0;
+		else
+			page_stat = ret;
+
+		update_write_page(page, page_stat);
+		unlock_page(page);
+		EXOFS_DBGMSG2("    writepages_done(0x%lx, 0x%lx) status=%d\n",
+			     inode->i_ino, page->index, page_stat);
+
+		length += PAGE_SIZE;
+	}
+
+	pcol_free(pcol);
+	kfree(pcol);
+	EXOFS_DBGMSG2("writepages_done END\n");
+}
+
+static struct page *__r4w_get_page(void *priv, u64 offset, bool *uptodate)
+{
+	struct page_collect *pcol = priv;
+	pgoff_t index = offset / PAGE_SIZE;
+
+	if (!pcol->that_locked_page ||
+	    (pcol->that_locked_page->index != index)) {
+		struct page *page;
+		loff_t i_size = i_size_read(pcol->inode);
+
+		if (offset >= i_size) {
+			*uptodate = true;
+			EXOFS_DBGMSG2("offset >= i_size index=0x%lx\n", index);
+			return ZERO_PAGE(0);
+		}
+
+		page =  find_get_page(pcol->inode->i_mapping, index);
+		if (!page) {
+			page = find_or_create_page(pcol->inode->i_mapping,
+						   index, GFP_NOFS);
+			if (unlikely(!page)) {
+				EXOFS_DBGMSG("grab_cache_page Failed "
+					"index=0x%llx\n", _LLU(index));
+				return NULL;
+			}
+			unlock_page(page);
+		}
+		*uptodate = PageUptodate(page);
+		EXOFS_DBGMSG2("index=0x%lx uptodate=%d\n", index, *uptodate);
+		return page;
+	} else {
+		EXOFS_DBGMSG2("YES that_locked_page index=0x%lx\n",
+			     pcol->that_locked_page->index);
+		*uptodate = true;
+		return pcol->that_locked_page;
+	}
+}
+
+static void __r4w_put_page(void *priv, struct page *page)
+{
+	struct page_collect *pcol = priv;
+
+	if ((pcol->that_locked_page != page) && (ZERO_PAGE(0) != page)) {
+		EXOFS_DBGMSG2("index=0x%lx\n", page->index);
+		put_page(page);
+		return;
+	}
+	EXOFS_DBGMSG2("that_locked_page index=0x%lx\n",
+		     ZERO_PAGE(0) == page ? -1 : page->index);
+}
+
+static const struct _ore_r4w_op _r4w_op = {
+	.get_page = &__r4w_get_page,
+	.put_page = &__r4w_put_page,
+};
+
+static int write_exec(struct page_collect *pcol)
+{
+	struct exofs_i_info *oi = exofs_i(pcol->inode);
+	struct ore_io_state *ios;
+	struct page_collect *pcol_copy = NULL;
+	int ret;
+
+	if (!pcol->pages)
+		return 0;
+
+	BUG_ON(pcol->ios);
+	ret = ore_get_rw_state(&pcol->sbi->layout, &oi->oc, false,
+				 pcol->pg_first << PAGE_SHIFT,
+				 pcol->length, &pcol->ios);
+	if (unlikely(ret))
+		goto err;
+
+	pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
+	if (!pcol_copy) {
+		EXOFS_ERR("write_exec: Failed to kmalloc(pcol)\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	*pcol_copy = *pcol;
+
+	ios = pcol->ios;
+	ios->pages = pcol_copy->pages;
+	ios->done = writepages_done;
+	ios->r4w = &_r4w_op;
+	ios->private = pcol_copy;
+
+	/* pages ownership was passed to pcol_copy */
+	_pcol_reset(pcol);
+
+	ret = _maybe_not_all_in_one_io(ios, pcol_copy, pcol);
+	if (unlikely(ret))
+		goto err;
+
+	EXOFS_DBGMSG2("write_exec(0x%lx) offset=0x%llx length=0x%llx\n",
+		pcol->inode->i_ino, _LLU(ios->offset), _LLU(ios->length));
+
+	ret = ore_write(ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("write_exec: ore_write() Failed\n");
+		goto err;
+	}
+
+	atomic_inc(&pcol->sbi->s_curr_pending);
+	return 0;
+
+err:
+	if (!pcol_copy) /* Failed before ownership transfer */
+		pcol_copy = pcol;
+	_unlock_pcol_pages(pcol_copy, ret, WRITE);
+	pcol_free(pcol_copy);
+	kfree(pcol_copy);
+
+	return ret;
+}
+
+/* writepage_strip is called either directly from writepage() or by the VFS from
+ * within write_cache_pages(), to add one more page to be written to storage.
+ * It will try to collect as many contiguous pages as possible. If a
+ * discontinuity is encountered or it runs out of resources it will submit the
+ * previous segment and will start a new collection.
+ * Eventually caller must submit the last segment if present.
+ */
+static int writepage_strip(struct page *page,
+			   struct writeback_control *wbc_unused, void *data)
+{
+	struct page_collect *pcol = data;
+	struct inode *inode = pcol->inode;
+	struct exofs_i_info *oi = exofs_i(inode);
+	loff_t i_size = i_size_read(inode);
+	pgoff_t end_index = i_size >> PAGE_SHIFT;
+	size_t len;
+	int ret;
+
+	BUG_ON(!PageLocked(page));
+
+	ret = wait_obj_created(oi);
+	if (unlikely(ret))
+		goto fail;
+
+	if (page->index < end_index)
+		/* in this case, the page is within the limits of the file */
+		len = PAGE_SIZE;
+	else {
+		len = i_size & ~PAGE_MASK;
+
+		if (page->index > end_index || !len) {
+			/* in this case, the page is outside the limits
+			 * (truncate in progress)
+			 */
+			ret = write_exec(pcol);
+			if (unlikely(ret))
+				goto fail;
+			if (PageError(page))
+				ClearPageError(page);
+			unlock_page(page);
+			EXOFS_DBGMSG("writepage_strip(0x%lx, 0x%lx) "
+				     "outside the limits\n",
+				     inode->i_ino, page->index);
+			return 0;
+		}
+	}
+
+try_again:
+
+	if (unlikely(pcol->pg_first == -1)) {
+		pcol->pg_first = page->index;
+	} else if (unlikely((pcol->pg_first + pcol->nr_pages) !=
+		   page->index)) {
+		/* Discontinuity detected, split the request */
+		ret = write_exec(pcol);
+		if (unlikely(ret))
+			goto fail;
+
+		EXOFS_DBGMSG("writepage_strip(0x%lx, 0x%lx) Discontinuity\n",
+			     inode->i_ino, page->index);
+		goto try_again;
+	}
+
+	if (!pcol->pages) {
+		ret = pcol_try_alloc(pcol);
+		if (unlikely(ret))
+			goto fail;
+	}
+
+	EXOFS_DBGMSG2("    writepage_strip(0x%lx, 0x%lx) len=0x%zx\n",
+		     inode->i_ino, page->index, len);
+
+	ret = pcol_add_page(pcol, page, len);
+	if (unlikely(ret)) {
+		EXOFS_DBGMSG2("Failed pcol_add_page "
+			     "nr_pages=%u total_length=0x%lx\n",
+			     pcol->nr_pages, pcol->length);
+
+		/* split the request, next loop will start again */
+		ret = write_exec(pcol);
+		if (unlikely(ret)) {
+			EXOFS_DBGMSG("write_exec failed => %d", ret);
+			goto fail;
+		}
+
+		goto try_again;
+	}
+
+	BUG_ON(PageWriteback(page));
+	set_page_writeback(page);
+
+	return 0;
+
+fail:
+	EXOFS_DBGMSG("Error: writepage_strip(0x%lx, 0x%lx)=>%d\n",
+		     inode->i_ino, page->index, ret);
+	mapping_set_error(page->mapping, -EIO);
+	unlock_page(page);
+	return ret;
+}
+
+static int exofs_writepages(struct address_space *mapping,
+		       struct writeback_control *wbc)
+{
+	struct page_collect pcol;
+	long start, end, expected_pages;
+	int ret;
+
+	start = wbc->range_start >> PAGE_SHIFT;
+	end = (wbc->range_end == LLONG_MAX) ?
+			start + mapping->nrpages :
+			wbc->range_end >> PAGE_SHIFT;
+
+	if (start || end)
+		expected_pages = end - start + 1;
+	else
+		expected_pages = mapping->nrpages;
+
+	if (expected_pages < 32L)
+		expected_pages = 32L;
+
+	EXOFS_DBGMSG2("inode(0x%lx) wbc->start=0x%llx wbc->end=0x%llx "
+		     "nrpages=%lu start=0x%lx end=0x%lx expected_pages=%ld\n",
+		     mapping->host->i_ino, wbc->range_start, wbc->range_end,
+		     mapping->nrpages, start, end, expected_pages);
+
+	_pcol_init(&pcol, expected_pages, mapping->host);
+
+	ret = write_cache_pages(mapping, wbc, writepage_strip, &pcol);
+	if (unlikely(ret)) {
+		EXOFS_ERR("write_cache_pages => %d\n", ret);
+		return ret;
+	}
+
+	ret = write_exec(&pcol);
+	if (unlikely(ret))
+		return ret;
+
+	if (wbc->sync_mode == WB_SYNC_ALL) {
+		return write_exec(&pcol); /* pump the last reminder */
+	} else if (pcol.nr_pages) {
+		/* not SYNC let the reminder join the next writeout */
+		unsigned i;
+
+		for (i = 0; i < pcol.nr_pages; i++) {
+			struct page *page = pcol.pages[i];
+
+			end_page_writeback(page);
+			set_page_dirty(page);
+			unlock_page(page);
+		}
+	}
+	return 0;
+}
+
+/*
+static int exofs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct page_collect pcol;
+	int ret;
+
+	_pcol_init(&pcol, 1, page->mapping->host);
+
+	ret = writepage_strip(page, NULL, &pcol);
+	if (ret) {
+		EXOFS_ERR("exofs_writepage => %d\n", ret);
+		return ret;
+	}
+
+	return write_exec(&pcol);
+}
+*/
+/* i_mutex held using inode->i_size directly */
+static void _write_failed(struct inode *inode, loff_t to)
+{
+	if (to > inode->i_size)
+		truncate_pagecache(inode, inode->i_size);
+}
+
+int exofs_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata)
+{
+	int ret = 0;
+	struct page *page;
+
+	page = *pagep;
+	if (page == NULL) {
+		page = grab_cache_page_write_begin(mapping, pos >> PAGE_SHIFT,
+						   flags);
+		if (!page) {
+			EXOFS_DBGMSG("grab_cache_page_write_begin failed\n");
+			return -ENOMEM;
+		}
+		*pagep = page;
+	}
+
+	 /* read modify write */
+	if (!PageUptodate(page) && (len != PAGE_SIZE)) {
+		loff_t i_size = i_size_read(mapping->host);
+		pgoff_t end_index = i_size >> PAGE_SHIFT;
+
+		if (page->index > end_index) {
+			clear_highpage(page);
+			SetPageUptodate(page);
+		} else {
+			ret = _readpage(page, true);
+			if (ret) {
+				unlock_page(page);
+				EXOFS_DBGMSG("__readpage failed\n");
+			}
+		}
+	}
+	return ret;
+}
+
+static int exofs_write_begin_export(struct file *file,
+		struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata)
+{
+	*pagep = NULL;
+
+	return exofs_write_begin(file, mapping, pos, len, flags, pagep,
+					fsdata);
+}
+
+static int exofs_write_end(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	loff_t last_pos = pos + copied;
+
+	if (!PageUptodate(page)) {
+		if (copied < len) {
+			_write_failed(inode, pos + len);
+			copied = 0;
+			goto out;
+		}
+		SetPageUptodate(page);
+	}
+	if (last_pos > inode->i_size) {
+		i_size_write(inode, last_pos);
+		mark_inode_dirty(inode);
+	}
+	set_page_dirty(page);
+out:
+	unlock_page(page);
+	put_page(page);
+	return copied;
+}
+
+static int exofs_releasepage(struct page *page, gfp_t gfp)
+{
+	EXOFS_DBGMSG("page 0x%lx\n", page->index);
+	WARN_ON(1);
+	return 0;
+}
+
+static void exofs_invalidatepage(struct page *page, unsigned int offset,
+				 unsigned int length)
+{
+	EXOFS_DBGMSG("page 0x%lx offset 0x%x length 0x%x\n",
+		     page->index, offset, length);
+	WARN_ON(1);
+}
+
+
+ /* TODO: Should be easy enough to do proprly */
+static ssize_t exofs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
+{
+	return 0;
+}
+
+const struct address_space_operations exofs_aops = {
+	.readpage	= exofs_readpage,
+	.readpages	= exofs_readpages,
+	.writepage	= NULL,
+	.writepages	= exofs_writepages,
+	.write_begin	= exofs_write_begin_export,
+	.write_end	= exofs_write_end,
+	.releasepage	= exofs_releasepage,
+	.set_page_dirty	= __set_page_dirty_nobuffers,
+	.invalidatepage = exofs_invalidatepage,
+
+	/* Not implemented Yet */
+	.bmap		= NULL, /* TODO: use osd's OSD_ACT_READ_MAP */
+	.direct_IO	= exofs_direct_IO,
+
+	/* With these NULL has special meaning or default is not exported */
+	.migratepage	= NULL,
+	.launder_page	= NULL,
+	.is_partially_uptodate = NULL,
+	.error_remove_page = NULL,
+};
+
+/******************************************************************************
+ * INODE OPERATIONS
+ *****************************************************************************/
+
+/*
+ * Test whether an inode is a fast symlink.
+ */
+static inline int exofs_inode_is_fast_symlink(struct inode *inode)
+{
+	struct exofs_i_info *oi = exofs_i(inode);
+
+	return S_ISLNK(inode->i_mode) && (oi->i_data[0] != 0);
+}
+
+static int _do_truncate(struct inode *inode, loff_t newsize)
+{
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	int ret;
+
+	inode->i_mtime = inode->i_ctime = current_time(inode);
+
+	ret = ore_truncate(&sbi->layout, &oi->oc, (u64)newsize);
+	if (likely(!ret))
+		truncate_setsize(inode, newsize);
+
+	EXOFS_DBGMSG2("(0x%lx) size=0x%llx ret=>%d\n",
+		     inode->i_ino, newsize, ret);
+	return ret;
+}
+
+/*
+ * Set inode attributes - update size attribute on OSD if needed,
+ *                        otherwise just call generic functions.
+ */
+int exofs_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = d_inode(dentry);
+	int error;
+
+	/* if we are about to modify an object, and it hasn't been
+	 * created yet, wait
+	 */
+	error = wait_obj_created(exofs_i(inode));
+	if (unlikely(error))
+		return error;
+
+	error = setattr_prepare(dentry, iattr);
+	if (unlikely(error))
+		return error;
+
+	if ((iattr->ia_valid & ATTR_SIZE) &&
+	    iattr->ia_size != i_size_read(inode)) {
+		error = _do_truncate(inode, iattr->ia_size);
+		if (unlikely(error))
+			return error;
+	}
+
+	setattr_copy(inode, iattr);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+static const struct osd_attr g_attr_inode_file_layout = ATTR_DEF(
+	EXOFS_APAGE_FS_DATA,
+	EXOFS_ATTR_INODE_FILE_LAYOUT,
+	0);
+static const struct osd_attr g_attr_inode_dir_layout = ATTR_DEF(
+	EXOFS_APAGE_FS_DATA,
+	EXOFS_ATTR_INODE_DIR_LAYOUT,
+	0);
+
+/*
+ * Read the Linux inode info from the OSD, and return it as is. In exofs the
+ * inode info is in an application specific page/attribute of the osd-object.
+ */
+static int exofs_get_inode(struct super_block *sb, struct exofs_i_info *oi,
+		    struct exofs_fcb *inode)
+{
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct osd_attr attrs[] = {
+		[0] = g_attr_inode_data,
+		[1] = g_attr_inode_file_layout,
+		[2] = g_attr_inode_dir_layout,
+	};
+	struct ore_io_state *ios;
+	struct exofs_on_disk_inode_layout *layout;
+	int ret;
+
+	ret = ore_get_io_state(&sbi->layout, &oi->oc, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: ore_get_io_state failed.\n", __func__);
+		return ret;
+	}
+
+	attrs[1].len = exofs_on_disk_inode_layout_size(sbi->oc.numdevs);
+	attrs[2].len = exofs_on_disk_inode_layout_size(sbi->oc.numdevs);
+
+	ios->in_attr = attrs;
+	ios->in_attr_len = ARRAY_SIZE(attrs);
+
+	ret = ore_read(ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("object(0x%llx) corrupted, return empty file=>%d\n",
+			  _LLU(oi->one_comp.obj.id), ret);
+		memset(inode, 0, sizeof(*inode));
+		inode->i_mode = 0040000 | (0777 & ~022);
+		/* If object is lost on target we might as well enable it's
+		 * delete.
+		 */
+		ret = 0;
+		goto out;
+	}
+
+	ret = extract_attr_from_ios(ios, &attrs[0]);
+	if (ret) {
+		EXOFS_ERR("%s: extract_attr 0 of inode failed\n", __func__);
+		goto out;
+	}
+	WARN_ON(attrs[0].len != EXOFS_INO_ATTR_SIZE);
+	memcpy(inode, attrs[0].val_ptr, EXOFS_INO_ATTR_SIZE);
+
+	ret = extract_attr_from_ios(ios, &attrs[1]);
+	if (ret) {
+		EXOFS_ERR("%s: extract_attr 1 of inode failed\n", __func__);
+		goto out;
+	}
+	if (attrs[1].len) {
+		layout = attrs[1].val_ptr;
+		if (layout->gen_func != cpu_to_le16(LAYOUT_MOVING_WINDOW)) {
+			EXOFS_ERR("%s: unsupported files layout %d\n",
+				__func__, layout->gen_func);
+			ret = -ENOTSUPP;
+			goto out;
+		}
+	}
+
+	ret = extract_attr_from_ios(ios, &attrs[2]);
+	if (ret) {
+		EXOFS_ERR("%s: extract_attr 2 of inode failed\n", __func__);
+		goto out;
+	}
+	if (attrs[2].len) {
+		layout = attrs[2].val_ptr;
+		if (layout->gen_func != cpu_to_le16(LAYOUT_MOVING_WINDOW)) {
+			EXOFS_ERR("%s: unsupported meta-data layout %d\n",
+				__func__, layout->gen_func);
+			ret = -ENOTSUPP;
+			goto out;
+		}
+	}
+
+out:
+	ore_put_io_state(ios);
+	return ret;
+}
+
+static void __oi_init(struct exofs_i_info *oi)
+{
+	init_waitqueue_head(&oi->i_wq);
+	oi->i_flags = 0;
+}
+/*
+ * Fill in an inode read from the OSD and set it up for use
+ */
+struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
+{
+	struct exofs_i_info *oi;
+	struct exofs_fcb fcb;
+	struct inode *inode;
+	int ret;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+	oi = exofs_i(inode);
+	__oi_init(oi);
+	exofs_init_comps(&oi->oc, &oi->one_comp, sb->s_fs_info,
+			 exofs_oi_objno(oi));
+
+	/* read the inode from the osd */
+	ret = exofs_get_inode(sb, oi, &fcb);
+	if (ret)
+		goto bad_inode;
+
+	set_obj_created(oi);
+
+	/* copy stuff from on-disk struct to in-memory struct */
+	inode->i_mode = le16_to_cpu(fcb.i_mode);
+	i_uid_write(inode, le32_to_cpu(fcb.i_uid));
+	i_gid_write(inode, le32_to_cpu(fcb.i_gid));
+	set_nlink(inode, le16_to_cpu(fcb.i_links_count));
+	inode->i_ctime.tv_sec = (signed)le32_to_cpu(fcb.i_ctime);
+	inode->i_atime.tv_sec = (signed)le32_to_cpu(fcb.i_atime);
+	inode->i_mtime.tv_sec = (signed)le32_to_cpu(fcb.i_mtime);
+	inode->i_ctime.tv_nsec =
+		inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = 0;
+	oi->i_commit_size = le64_to_cpu(fcb.i_size);
+	i_size_write(inode, oi->i_commit_size);
+	inode->i_blkbits = EXOFS_BLKSHIFT;
+	inode->i_generation = le32_to_cpu(fcb.i_generation);
+
+	oi->i_dir_start_lookup = 0;
+
+	if ((inode->i_nlink == 0) && (inode->i_mode == 0)) {
+		ret = -ESTALE;
+		goto bad_inode;
+	}
+
+	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+		if (fcb.i_data[0])
+			inode->i_rdev =
+				old_decode_dev(le32_to_cpu(fcb.i_data[0]));
+		else
+			inode->i_rdev =
+				new_decode_dev(le32_to_cpu(fcb.i_data[1]));
+	} else {
+		memcpy(oi->i_data, fcb.i_data, sizeof(fcb.i_data));
+	}
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = &exofs_file_inode_operations;
+		inode->i_fop = &exofs_file_operations;
+		inode->i_mapping->a_ops = &exofs_aops;
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = &exofs_dir_inode_operations;
+		inode->i_fop = &exofs_dir_operations;
+		inode->i_mapping->a_ops = &exofs_aops;
+	} else if (S_ISLNK(inode->i_mode)) {
+		if (exofs_inode_is_fast_symlink(inode)) {
+			inode->i_op = &simple_symlink_inode_operations;
+			inode->i_link = (char *)oi->i_data;
+		} else {
+			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
+			inode->i_mapping->a_ops = &exofs_aops;
+		}
+	} else {
+		inode->i_op = &exofs_special_inode_operations;
+		if (fcb.i_data[0])
+			init_special_inode(inode, inode->i_mode,
+			   old_decode_dev(le32_to_cpu(fcb.i_data[0])));
+		else
+			init_special_inode(inode, inode->i_mode,
+			   new_decode_dev(le32_to_cpu(fcb.i_data[1])));
+	}
+
+	unlock_new_inode(inode);
+	return inode;
+
+bad_inode:
+	iget_failed(inode);
+	return ERR_PTR(ret);
+}
+
+int __exofs_wait_obj_created(struct exofs_i_info *oi)
+{
+	if (!obj_created(oi)) {
+		EXOFS_DBGMSG("!obj_created\n");
+		BUG_ON(!obj_2bcreated(oi));
+		wait_event(oi->i_wq, obj_created(oi));
+		EXOFS_DBGMSG("wait_event done\n");
+	}
+	return unlikely(is_bad_inode(&oi->vfs_inode)) ? -EIO : 0;
+}
+
+/*
+ * Callback function from exofs_new_inode().  The important thing is that we
+ * set the obj_created flag so that other methods know that the object exists on
+ * the OSD.
+ */
+static void create_done(struct ore_io_state *ios, void *p)
+{
+	struct inode *inode = p;
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	int ret;
+
+	ret = ore_check_io(ios, NULL);
+	ore_put_io_state(ios);
+
+	atomic_dec(&sbi->s_curr_pending);
+
+	if (unlikely(ret)) {
+		EXOFS_ERR("object=0x%llx creation failed in pid=0x%llx",
+			  _LLU(exofs_oi_objno(oi)),
+			  _LLU(oi->one_comp.obj.partition));
+		/*TODO: When FS is corrupted creation can fail, object already
+		 * exist. Get rid of this asynchronous creation, if exist
+		 * increment the obj counter and try the next object. Until we
+		 * succeed. All these dangling objects will be made into lost
+		 * files by chkfs.exofs
+		 */
+	}
+
+	set_obj_created(oi);
+
+	wake_up(&oi->i_wq);
+}
+
+/*
+ * Set up a new inode and create an object for it on the OSD
+ */
+struct inode *exofs_new_inode(struct inode *dir, umode_t mode)
+{
+	struct super_block *sb = dir->i_sb;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct inode *inode;
+	struct exofs_i_info *oi;
+	struct ore_io_state *ios;
+	int ret;
+
+	inode = new_inode(sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	oi = exofs_i(inode);
+	__oi_init(oi);
+
+	set_obj_2bcreated(oi);
+
+	inode_init_owner(inode, dir, mode);
+	inode->i_ino = sbi->s_nextid++;
+	inode->i_blkbits = EXOFS_BLKSHIFT;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	oi->i_commit_size = inode->i_size = 0;
+	spin_lock(&sbi->s_next_gen_lock);
+	inode->i_generation = sbi->s_next_generation++;
+	spin_unlock(&sbi->s_next_gen_lock);
+	insert_inode_hash(inode);
+
+	exofs_init_comps(&oi->oc, &oi->one_comp, sb->s_fs_info,
+			 exofs_oi_objno(oi));
+	exofs_sbi_write_stats(sbi); /* Make sure new sbi->s_nextid is on disk */
+
+	mark_inode_dirty(inode);
+
+	ret = ore_get_io_state(&sbi->layout, &oi->oc, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("exofs_new_inode: ore_get_io_state failed\n");
+		return ERR_PTR(ret);
+	}
+
+	ios->done = create_done;
+	ios->private = inode;
+
+	ret = ore_create(ios);
+	if (ret) {
+		ore_put_io_state(ios);
+		return ERR_PTR(ret);
+	}
+	atomic_inc(&sbi->s_curr_pending);
+
+	return inode;
+}
+
+/*
+ * struct to pass two arguments to update_inode's callback
+ */
+struct updatei_args {
+	struct exofs_sb_info	*sbi;
+	struct exofs_fcb	fcb;
+};
+
+/*
+ * Callback function from exofs_update_inode().
+ */
+static void updatei_done(struct ore_io_state *ios, void *p)
+{
+	struct updatei_args *args = p;
+
+	ore_put_io_state(ios);
+
+	atomic_dec(&args->sbi->s_curr_pending);
+
+	kfree(args);
+}
+
+/*
+ * Write the inode to the OSD.  Just fill up the struct, and set the attribute
+ * synchronously or asynchronously depending on the do_sync flag.
+ */
+static int exofs_update_inode(struct inode *inode, int do_sync)
+{
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct super_block *sb = inode->i_sb;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct ore_io_state *ios;
+	struct osd_attr attr;
+	struct exofs_fcb *fcb;
+	struct updatei_args *args;
+	int ret;
+
+	args = kzalloc(sizeof(*args), GFP_KERNEL);
+	if (!args) {
+		EXOFS_DBGMSG("Failed kzalloc of args\n");
+		return -ENOMEM;
+	}
+
+	fcb = &args->fcb;
+
+	fcb->i_mode = cpu_to_le16(inode->i_mode);
+	fcb->i_uid = cpu_to_le32(i_uid_read(inode));
+	fcb->i_gid = cpu_to_le32(i_gid_read(inode));
+	fcb->i_links_count = cpu_to_le16(inode->i_nlink);
+	fcb->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
+	fcb->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
+	fcb->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
+	oi->i_commit_size = i_size_read(inode);
+	fcb->i_size = cpu_to_le64(oi->i_commit_size);
+	fcb->i_generation = cpu_to_le32(inode->i_generation);
+
+	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+		if (old_valid_dev(inode->i_rdev)) {
+			fcb->i_data[0] =
+				cpu_to_le32(old_encode_dev(inode->i_rdev));
+			fcb->i_data[1] = 0;
+		} else {
+			fcb->i_data[0] = 0;
+			fcb->i_data[1] =
+				cpu_to_le32(new_encode_dev(inode->i_rdev));
+			fcb->i_data[2] = 0;
+		}
+	} else
+		memcpy(fcb->i_data, oi->i_data, sizeof(fcb->i_data));
+
+	ret = ore_get_io_state(&sbi->layout, &oi->oc, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: ore_get_io_state failed.\n", __func__);
+		goto free_args;
+	}
+
+	attr = g_attr_inode_data;
+	attr.val_ptr = fcb;
+	ios->out_attr_len = 1;
+	ios->out_attr = &attr;
+
+	wait_obj_created(oi);
+
+	if (!do_sync) {
+		args->sbi = sbi;
+		ios->done = updatei_done;
+		ios->private = args;
+	}
+
+	ret = ore_write(ios);
+	if (!do_sync && !ret) {
+		atomic_inc(&sbi->s_curr_pending);
+		goto out; /* deallocation in updatei_done */
+	}
+
+	ore_put_io_state(ios);
+free_args:
+	kfree(args);
+out:
+	EXOFS_DBGMSG("(0x%lx) do_sync=%d ret=>%d\n",
+		     inode->i_ino, do_sync, ret);
+	return ret;
+}
+
+int exofs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	/* FIXME: fix fsync and use wbc->sync_mode == WB_SYNC_ALL */
+	return exofs_update_inode(inode, 1);
+}
+
+/*
+ * Callback function from exofs_delete_inode() - don't have much cleaning up to
+ * do.
+ */
+static void delete_done(struct ore_io_state *ios, void *p)
+{
+	struct exofs_sb_info *sbi = p;
+
+	ore_put_io_state(ios);
+
+	atomic_dec(&sbi->s_curr_pending);
+}
+
+/*
+ * Called when the refcount of an inode reaches zero.  We remove the object
+ * from the OSD here.  We make sure the object was created before we try and
+ * delete it.
+ */
+void exofs_evict_inode(struct inode *inode)
+{
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct super_block *sb = inode->i_sb;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct ore_io_state *ios;
+	int ret;
+
+	truncate_inode_pages_final(&inode->i_data);
+
+	/* TODO: should do better here */
+	if (inode->i_nlink || is_bad_inode(inode))
+		goto no_delete;
+
+	inode->i_size = 0;
+	clear_inode(inode);
+
+	/* if we are deleting an obj that hasn't been created yet, wait.
+	 * This also makes sure that create_done cannot be called with an
+	 * already evicted inode.
+	 */
+	wait_obj_created(oi);
+	/* ignore the error, attempt a remove anyway */
+
+	/* Now Remove the OSD objects */
+	ret = ore_get_io_state(&sbi->layout, &oi->oc, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: ore_get_io_state failed\n", __func__);
+		return;
+	}
+
+	ios->done = delete_done;
+	ios->private = sbi;
+
+	ret = ore_remove(ios);
+	if (ret) {
+		EXOFS_ERR("%s: ore_remove failed\n", __func__);
+		ore_put_io_state(ios);
+		return;
+	}
+	atomic_inc(&sbi->s_curr_pending);
+
+	return;
+
+no_delete:
+	clear_inode(inode);
+}
diff --git a/src/kernel/linux/v4.19/fs/exofs/namei.c b/src/kernel/linux/v4.19/fs/exofs/namei.c
new file mode 100644
index 0000000..7295cd7
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/namei.c
@@ -0,0 +1,323 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     Copyright (C) 1992, 1993, 1994, 1995
+ *     Remy Card (card@masi.ibp.fr)
+ *     Laboratoire MASI - Institut Blaise Pascal
+ *     Universite Pierre et Marie Curie (Paris VI)
+ *     from
+ *     linux/fs/minix/inode.c
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "exofs.h"
+
+static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
+{
+	int err = exofs_add_link(dentry, inode);
+	if (!err) {
+		d_instantiate(dentry, inode);
+		return 0;
+	}
+	inode_dec_link_count(inode);
+	iput(inode);
+	return err;
+}
+
+static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
+				   unsigned int flags)
+{
+	struct inode *inode;
+	ino_t ino;
+
+	if (dentry->d_name.len > EXOFS_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	ino = exofs_inode_by_name(dir, dentry);
+	inode = ino ? exofs_iget(dir->i_sb, ino) : NULL;
+	return d_splice_alias(inode, dentry);
+}
+
+static int exofs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+			 bool excl)
+{
+	struct inode *inode = exofs_new_inode(dir, mode);
+	int err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		inode->i_op = &exofs_file_inode_operations;
+		inode->i_fop = &exofs_file_operations;
+		inode->i_mapping->a_ops = &exofs_aops;
+		mark_inode_dirty(inode);
+		err = exofs_add_nondir(dentry, inode);
+	}
+	return err;
+}
+
+static int exofs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
+		       dev_t rdev)
+{
+	struct inode *inode;
+	int err;
+
+	inode = exofs_new_inode(dir, mode);
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		init_special_inode(inode, inode->i_mode, rdev);
+		mark_inode_dirty(inode);
+		err = exofs_add_nondir(dentry, inode);
+	}
+	return err;
+}
+
+static int exofs_symlink(struct inode *dir, struct dentry *dentry,
+			  const char *symname)
+{
+	struct super_block *sb = dir->i_sb;
+	int err = -ENAMETOOLONG;
+	unsigned l = strlen(symname)+1;
+	struct inode *inode;
+	struct exofs_i_info *oi;
+
+	if (l > sb->s_blocksize)
+		goto out;
+
+	inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out;
+
+	oi = exofs_i(inode);
+	if (l > sizeof(oi->i_data)) {
+		/* slow symlink */
+		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
+		inode->i_mapping->a_ops = &exofs_aops;
+		memset(oi->i_data, 0, sizeof(oi->i_data));
+
+		err = page_symlink(inode, symname, l);
+		if (err)
+			goto out_fail;
+	} else {
+		/* fast symlink */
+		inode->i_op = &simple_symlink_inode_operations;
+		inode->i_link = (char *)oi->i_data;
+		memcpy(oi->i_data, symname, l);
+		inode->i_size = l-1;
+	}
+	mark_inode_dirty(inode);
+
+	err = exofs_add_nondir(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	iput(inode);
+	goto out;
+}
+
+static int exofs_link(struct dentry *old_dentry, struct inode *dir,
+		struct dentry *dentry)
+{
+	struct inode *inode = d_inode(old_dentry);
+
+	inode->i_ctime = current_time(inode);
+	inode_inc_link_count(inode);
+	ihold(inode);
+
+	return exofs_add_nondir(dentry, inode);
+}
+
+static int exofs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+	struct inode *inode;
+	int err;
+
+	inode_inc_link_count(dir);
+
+	inode = exofs_new_inode(dir, S_IFDIR | mode);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_dir;
+
+	inode->i_op = &exofs_dir_inode_operations;
+	inode->i_fop = &exofs_dir_operations;
+	inode->i_mapping->a_ops = &exofs_aops;
+
+	inode_inc_link_count(inode);
+
+	err = exofs_make_empty(inode, dir);
+	if (err)
+		goto out_fail;
+
+	err = exofs_add_link(dentry, inode);
+	if (err)
+		goto out_fail;
+
+	d_instantiate(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	inode_dec_link_count(inode);
+	iput(inode);
+out_dir:
+	inode_dec_link_count(dir);
+	goto out;
+}
+
+static int exofs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	struct exofs_dir_entry *de;
+	struct page *page;
+	int err = -ENOENT;
+
+	de = exofs_find_entry(dir, dentry, &page);
+	if (!de)
+		goto out;
+
+	err = exofs_delete_entry(de, page);
+	if (err)
+		goto out;
+
+	inode->i_ctime = dir->i_ctime;
+	inode_dec_link_count(inode);
+	err = 0;
+out:
+	return err;
+}
+
+static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	int err = -ENOTEMPTY;
+
+	if (exofs_empty_dir(inode)) {
+		err = exofs_unlink(dir, dentry);
+		if (!err) {
+			inode->i_size = 0;
+			inode_dec_link_count(inode);
+			inode_dec_link_count(dir);
+		}
+	}
+	return err;
+}
+
+static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
+			struct inode *new_dir, struct dentry *new_dentry,
+			unsigned int flags)
+{
+	struct inode *old_inode = d_inode(old_dentry);
+	struct inode *new_inode = d_inode(new_dentry);
+	struct page *dir_page = NULL;
+	struct exofs_dir_entry *dir_de = NULL;
+	struct page *old_page;
+	struct exofs_dir_entry *old_de;
+	int err = -ENOENT;
+
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
+	if (!old_de)
+		goto out;
+
+	if (S_ISDIR(old_inode->i_mode)) {
+		err = -EIO;
+		dir_de = exofs_dotdot(old_inode, &dir_page);
+		if (!dir_de)
+			goto out_old;
+	}
+
+	if (new_inode) {
+		struct page *new_page;
+		struct exofs_dir_entry *new_de;
+
+		err = -ENOTEMPTY;
+		if (dir_de && !exofs_empty_dir(new_inode))
+			goto out_dir;
+
+		err = -ENOENT;
+		new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
+		if (!new_de)
+			goto out_dir;
+		err = exofs_set_link(new_dir, new_de, new_page, old_inode);
+		new_inode->i_ctime = current_time(new_inode);
+		if (dir_de)
+			drop_nlink(new_inode);
+		inode_dec_link_count(new_inode);
+		if (err)
+			goto out_dir;
+	} else {
+		err = exofs_add_link(new_dentry, old_inode);
+		if (err)
+			goto out_dir;
+		if (dir_de)
+			inode_inc_link_count(new_dir);
+	}
+
+	old_inode->i_ctime = current_time(old_inode);
+
+	exofs_delete_entry(old_de, old_page);
+	mark_inode_dirty(old_inode);
+
+	if (dir_de) {
+		err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
+		inode_dec_link_count(old_dir);
+		if (err)
+			goto out_dir;
+	}
+	return 0;
+
+
+out_dir:
+	if (dir_de) {
+		kunmap(dir_page);
+		put_page(dir_page);
+	}
+out_old:
+	kunmap(old_page);
+	put_page(old_page);
+out:
+	return err;
+}
+
+const struct inode_operations exofs_dir_inode_operations = {
+	.create 	= exofs_create,
+	.lookup 	= exofs_lookup,
+	.link   	= exofs_link,
+	.unlink 	= exofs_unlink,
+	.symlink	= exofs_symlink,
+	.mkdir  	= exofs_mkdir,
+	.rmdir  	= exofs_rmdir,
+	.mknod  	= exofs_mknod,
+	.rename		= exofs_rename,
+	.setattr	= exofs_setattr,
+};
+
+const struct inode_operations exofs_special_inode_operations = {
+	.setattr	= exofs_setattr,
+};
diff --git a/src/kernel/linux/v4.19/fs/exofs/ore.c b/src/kernel/linux/v4.19/fs/exofs/ore.c
new file mode 100644
index 0000000..5331a15
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/ore.c
@@ -0,0 +1,1178 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <asm/div64.h>
+#include <linux/lcm.h>
+
+#include "ore_raid.h"
+
+MODULE_AUTHOR("Boaz Harrosh <ooo@electrozaur.com>");
+MODULE_DESCRIPTION("Objects Raid Engine ore.ko");
+MODULE_LICENSE("GPL");
+
+/* ore_verify_layout does a couple of things:
+ * 1. Given a minimum number of needed parameters fixes up the rest of the
+ *    members to be operatonals for the ore. The needed parameters are those
+ *    that are defined by the pnfs-objects layout STD.
+ * 2. Check to see if the current ore code actually supports these parameters
+ *    for example stripe_unit must be a multple of the system PAGE_SIZE,
+ *    and etc...
+ * 3. Cache some havily used calculations that will be needed by users.
+ */
+
+enum { BIO_MAX_PAGES_KMALLOC =
+		(PAGE_SIZE - sizeof(struct bio)) / sizeof(struct bio_vec),};
+
+int ore_verify_layout(unsigned total_comps, struct ore_layout *layout)
+{
+	u64 stripe_length;
+
+	switch (layout->raid_algorithm) {
+	case PNFS_OSD_RAID_0:
+		layout->parity = 0;
+		break;
+	case PNFS_OSD_RAID_5:
+		layout->parity = 1;
+		break;
+	case PNFS_OSD_RAID_PQ:
+		layout->parity = 2;
+		break;
+	case PNFS_OSD_RAID_4:
+	default:
+		ORE_ERR("Only RAID_0/5/6 for now received-enum=%d\n",
+			layout->raid_algorithm);
+		return -EINVAL;
+	}
+	if (0 != (layout->stripe_unit & ~PAGE_MASK)) {
+		ORE_ERR("Stripe Unit(0x%llx)"
+			  " must be Multples of PAGE_SIZE(0x%lx)\n",
+			  _LLU(layout->stripe_unit), PAGE_SIZE);
+		return -EINVAL;
+	}
+	if (layout->group_width) {
+		if (!layout->group_depth) {
+			ORE_ERR("group_depth == 0 && group_width != 0\n");
+			return -EINVAL;
+		}
+		if (total_comps < (layout->group_width * layout->mirrors_p1)) {
+			ORE_ERR("Data Map wrong, "
+				"numdevs=%d < group_width=%d * mirrors=%d\n",
+				total_comps, layout->group_width,
+				layout->mirrors_p1);
+			return -EINVAL;
+		}
+		layout->group_count = total_comps / layout->mirrors_p1 /
+						layout->group_width;
+	} else {
+		if (layout->group_depth) {
+			printk(KERN_NOTICE "Warning: group_depth ignored "
+				"group_width == 0 && group_depth == %lld\n",
+				_LLU(layout->group_depth));
+		}
+		layout->group_width = total_comps / layout->mirrors_p1;
+		layout->group_depth = -1;
+		layout->group_count = 1;
+	}
+
+	stripe_length = (u64)layout->group_width * layout->stripe_unit;
+	if (stripe_length >= (1ULL << 32)) {
+		ORE_ERR("Stripe_length(0x%llx) >= 32bit is not supported\n",
+			_LLU(stripe_length));
+		return -EINVAL;
+	}
+
+	layout->max_io_length =
+		(BIO_MAX_PAGES_KMALLOC * PAGE_SIZE - layout->stripe_unit) *
+					(layout->group_width - layout->parity);
+	if (layout->parity) {
+		unsigned stripe_length =
+				(layout->group_width - layout->parity) *
+				layout->stripe_unit;
+
+		layout->max_io_length /= stripe_length;
+		layout->max_io_length *= stripe_length;
+	}
+	ORE_DBGMSG("max_io_length=0x%lx\n", layout->max_io_length);
+
+	return 0;
+}
+EXPORT_SYMBOL(ore_verify_layout);
+
+static u8 *_ios_cred(struct ore_io_state *ios, unsigned index)
+{
+	return ios->oc->comps[index & ios->oc->single_comp].cred;
+}
+
+static struct osd_obj_id *_ios_obj(struct ore_io_state *ios, unsigned index)
+{
+	return &ios->oc->comps[index & ios->oc->single_comp].obj;
+}
+
+static struct osd_dev *_ios_od(struct ore_io_state *ios, unsigned index)
+{
+	ORE_DBGMSG2("oc->first_dev=%d oc->numdevs=%d i=%d oc->ods=%p\n",
+		    ios->oc->first_dev, ios->oc->numdevs, index,
+		    ios->oc->ods);
+
+	return ore_comp_dev(ios->oc, index);
+}
+
+int  _ore_get_io_state(struct ore_layout *layout,
+			struct ore_components *oc, unsigned numdevs,
+			unsigned sgs_per_dev, unsigned num_par_pages,
+			struct ore_io_state **pios)
+{
+	struct ore_io_state *ios;
+	size_t size_ios, size_extra, size_total;
+	void *ios_extra;
+
+	/*
+	 * The desired layout looks like this, with the extra_allocation
+	 * items pointed at from fields within ios or per_dev:
+
+	struct __alloc_all_io_state {
+		struct ore_io_state ios;
+		struct ore_per_dev_state per_dev[numdevs];
+		union {
+			struct osd_sg_entry sglist[sgs_per_dev * numdevs];
+			struct page *pages[num_par_pages];
+		} extra_allocation;
+	} whole_allocation;
+
+	*/
+
+	/* This should never happen, so abort early if it ever does. */
+	if (sgs_per_dev && num_par_pages) {
+		ORE_DBGMSG("Tried to use both pages and sglist\n");
+		*pios = NULL;
+		return -EINVAL;
+	}
+
+	if (numdevs > (INT_MAX - sizeof(*ios)) /
+		       sizeof(struct ore_per_dev_state))
+		return -ENOMEM;
+	size_ios = sizeof(*ios) + sizeof(struct ore_per_dev_state) * numdevs;
+
+	if (sgs_per_dev * numdevs > INT_MAX / sizeof(struct osd_sg_entry))
+		return -ENOMEM;
+	if (num_par_pages > INT_MAX / sizeof(struct page *))
+		return -ENOMEM;
+	size_extra = max(sizeof(struct osd_sg_entry) * (sgs_per_dev * numdevs),
+			 sizeof(struct page *) * num_par_pages);
+
+	size_total = size_ios + size_extra;
+
+	if (likely(size_total <= PAGE_SIZE)) {
+		ios = kzalloc(size_total, GFP_KERNEL);
+		if (unlikely(!ios)) {
+			ORE_DBGMSG("Failed kzalloc bytes=%zd\n", size_total);
+			*pios = NULL;
+			return -ENOMEM;
+		}
+		ios_extra = (char *)ios + size_ios;
+	} else {
+		ios = kzalloc(size_ios, GFP_KERNEL);
+		if (unlikely(!ios)) {
+			ORE_DBGMSG("Failed alloc first part bytes=%zd\n",
+				   size_ios);
+			*pios = NULL;
+			return -ENOMEM;
+		}
+		ios_extra = kzalloc(size_extra, GFP_KERNEL);
+		if (unlikely(!ios_extra)) {
+			ORE_DBGMSG("Failed alloc second part bytes=%zd\n",
+				   size_extra);
+			kfree(ios);
+			*pios = NULL;
+			return -ENOMEM;
+		}
+
+		/* In this case the per_dev[0].sgilist holds the pointer to
+		 * be freed
+		 */
+		ios->extra_part_alloc = true;
+	}
+
+	if (num_par_pages) {
+		ios->parity_pages = ios_extra;
+		ios->max_par_pages = num_par_pages;
+	}
+	if (sgs_per_dev) {
+		struct osd_sg_entry *sgilist = ios_extra;
+		unsigned d;
+
+		for (d = 0; d < numdevs; ++d) {
+			ios->per_dev[d].sglist = sgilist;
+			sgilist += sgs_per_dev;
+		}
+		ios->sgs_per_dev = sgs_per_dev;
+	}
+
+	ios->layout = layout;
+	ios->oc = oc;
+	*pios = ios;
+	return 0;
+}
+
+/* Allocate an io_state for only a single group of devices
+ *
+ * If a user needs to call ore_read/write() this version must be used becase it
+ * allocates extra stuff for striping and raid.
+ * The ore might decide to only IO less then @length bytes do to alignmets
+ * and constrains as follows:
+ * - The IO cannot cross group boundary.
+ * - In raid5/6 The end of the IO must align at end of a stripe eg.
+ *   (@offset + @length) % strip_size == 0. Or the complete range is within a
+ *   single stripe.
+ * - Memory condition only permitted a shorter IO. (A user can use @length=~0
+ *   And check the returned ios->length for max_io_size.)
+ *
+ * The caller must check returned ios->length (and/or ios->nr_pages) and
+ * re-issue these pages that fall outside of ios->length
+ */
+int  ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,
+		      bool is_reading, u64 offset, u64 length,
+		      struct ore_io_state **pios)
+{
+	struct ore_io_state *ios;
+	unsigned numdevs = layout->group_width * layout->mirrors_p1;
+	unsigned sgs_per_dev = 0, max_par_pages = 0;
+	int ret;
+
+	if (layout->parity && length) {
+		unsigned data_devs = layout->group_width - layout->parity;
+		unsigned stripe_size = layout->stripe_unit * data_devs;
+		unsigned pages_in_unit = layout->stripe_unit / PAGE_SIZE;
+		u32 remainder;
+		u64 num_stripes;
+		u64 num_raid_units;
+
+		num_stripes = div_u64_rem(length, stripe_size, &remainder);
+		if (remainder)
+			++num_stripes;
+
+		num_raid_units =  num_stripes * layout->parity;
+
+		if (is_reading) {
+			/* For reads add per_dev sglist array */
+			/* TODO: Raid 6 we need twice more. Actually:
+			*         num_stripes / LCMdP(W,P);
+			*         if (W%P != 0) num_stripes *= parity;
+			*/
+
+			/* first/last seg is split */
+			num_raid_units += layout->group_width;
+			sgs_per_dev = div_u64(num_raid_units, data_devs) + 2;
+		} else {
+			/* For Writes add parity pages array. */
+			max_par_pages = num_raid_units * pages_in_unit *
+						sizeof(struct page *);
+		}
+	}
+
+	ret = _ore_get_io_state(layout, oc, numdevs, sgs_per_dev, max_par_pages,
+				pios);
+	if (unlikely(ret))
+		return ret;
+
+	ios = *pios;
+	ios->reading = is_reading;
+	ios->offset = offset;
+
+	if (length) {
+		ore_calc_stripe_info(layout, offset, length, &ios->si);
+		ios->length = ios->si.length;
+		ios->nr_pages = ((ios->offset & (PAGE_SIZE - 1)) +
+				 ios->length + PAGE_SIZE - 1) / PAGE_SIZE;
+		if (layout->parity)
+			_ore_post_alloc_raid_stuff(ios);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(ore_get_rw_state);
+
+/* Allocate an io_state for all the devices in the comps array
+ *
+ * This version of io_state allocation is used mostly by create/remove
+ * and trunc where we currently need all the devices. The only wastful
+ * bit is the read/write_attributes with no IO. Those sites should
+ * be converted to use ore_get_rw_state() with length=0
+ */
+int  ore_get_io_state(struct ore_layout *layout, struct ore_components *oc,
+		      struct ore_io_state **pios)
+{
+	return _ore_get_io_state(layout, oc, oc->numdevs, 0, 0, pios);
+}
+EXPORT_SYMBOL(ore_get_io_state);
+
+void ore_put_io_state(struct ore_io_state *ios)
+{
+	if (ios) {
+		unsigned i;
+
+		for (i = 0; i < ios->numdevs; i++) {
+			struct ore_per_dev_state *per_dev = &ios->per_dev[i];
+
+			if (per_dev->or)
+				osd_end_request(per_dev->or);
+			if (per_dev->bio)
+				bio_put(per_dev->bio);
+		}
+
+		_ore_free_raid_stuff(ios);
+		kfree(ios);
+	}
+}
+EXPORT_SYMBOL(ore_put_io_state);
+
+static void _sync_done(struct ore_io_state *ios, void *p)
+{
+	struct completion *waiting = p;
+
+	complete(waiting);
+}
+
+static void _last_io(struct kref *kref)
+{
+	struct ore_io_state *ios = container_of(
+					kref, struct ore_io_state, kref);
+
+	ios->done(ios, ios->private);
+}
+
+static void _done_io(struct osd_request *or, void *p)
+{
+	struct ore_io_state *ios = p;
+
+	kref_put(&ios->kref, _last_io);
+}
+
+int ore_io_execute(struct ore_io_state *ios)
+{
+	DECLARE_COMPLETION_ONSTACK(wait);
+	bool sync = (ios->done == NULL);
+	int i, ret;
+
+	if (sync) {
+		ios->done = _sync_done;
+		ios->private = &wait;
+	}
+
+	for (i = 0; i < ios->numdevs; i++) {
+		struct osd_request *or = ios->per_dev[i].or;
+		if (unlikely(!or))
+			continue;
+
+		ret = osd_finalize_request(or, 0, _ios_cred(ios, i), NULL);
+		if (unlikely(ret)) {
+			ORE_DBGMSG("Failed to osd_finalize_request() => %d\n",
+				     ret);
+			return ret;
+		}
+	}
+
+	kref_init(&ios->kref);
+
+	for (i = 0; i < ios->numdevs; i++) {
+		struct osd_request *or = ios->per_dev[i].or;
+		if (unlikely(!or))
+			continue;
+
+		kref_get(&ios->kref);
+		osd_execute_request_async(or, _done_io, ios);
+	}
+
+	kref_put(&ios->kref, _last_io);
+	ret = 0;
+
+	if (sync) {
+		wait_for_completion(&wait);
+		ret = ore_check_io(ios, NULL);
+	}
+	return ret;
+}
+
+static void _clear_bio(struct bio *bio)
+{
+	struct bio_vec *bv;
+	unsigned i;
+
+	bio_for_each_segment_all(bv, bio, i) {
+		unsigned this_count = bv->bv_len;
+
+		if (likely(PAGE_SIZE == this_count))
+			clear_highpage(bv->bv_page);
+		else
+			zero_user(bv->bv_page, bv->bv_offset, this_count);
+	}
+}
+
+int ore_check_io(struct ore_io_state *ios, ore_on_dev_error on_dev_error)
+{
+	enum osd_err_priority acumulated_osd_err = 0;
+	int acumulated_lin_err = 0;
+	int i;
+
+	for (i = 0; i < ios->numdevs; i++) {
+		struct osd_sense_info osi;
+		struct ore_per_dev_state *per_dev = &ios->per_dev[i];
+		struct osd_request *or = per_dev->or;
+		int ret;
+
+		if (unlikely(!or))
+			continue;
+
+		ret = osd_req_decode_sense(or, &osi);
+		if (likely(!ret))
+			continue;
+
+		if ((OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) &&
+		    per_dev->bio) {
+			/* start read offset passed endof file.
+			 * Note: if we do not have bio it means read-attributes
+			 * In this case we should return error to caller.
+			 */
+			_clear_bio(per_dev->bio);
+			ORE_DBGMSG("start read offset passed end of file "
+				"offset=0x%llx, length=0x%llx\n",
+				_LLU(per_dev->offset),
+				_LLU(per_dev->length));
+
+			continue; /* we recovered */
+		}
+
+		if (on_dev_error) {
+			u64 residual = ios->reading ?
+					or->in.residual : or->out.residual;
+			u64 offset = (ios->offset + ios->length) - residual;
+			unsigned dev = per_dev->dev - ios->oc->first_dev;
+			struct ore_dev *od = ios->oc->ods[dev];
+
+			on_dev_error(ios, od, dev, osi.osd_err_pri,
+				     offset, residual);
+		}
+		if (osi.osd_err_pri >= acumulated_osd_err) {
+			acumulated_osd_err = osi.osd_err_pri;
+			acumulated_lin_err = ret;
+		}
+	}
+
+	return acumulated_lin_err;
+}
+EXPORT_SYMBOL(ore_check_io);
+
+/*
+ * L - logical offset into the file
+ *
+ * D - number of Data devices
+ *	D = group_width - parity
+ *
+ * U - The number of bytes in a stripe within a group
+ *	U =  stripe_unit * D
+ *
+ * T - The number of bytes striped within a group of component objects
+ *     (before advancing to the next group)
+ *	T = U * group_depth
+ *
+ * S - The number of bytes striped across all component objects
+ *     before the pattern repeats
+ *	S = T * group_count
+ *
+ * M - The "major" (i.e., across all components) cycle number
+ *	M = L / S
+ *
+ * G - Counts the groups from the beginning of the major cycle
+ *	G = (L - (M * S)) / T	[or (L % S) / T]
+ *
+ * H - The byte offset within the group
+ *	H = (L - (M * S)) % T	[or (L % S) % T]
+ *
+ * N - The "minor" (i.e., across the group) stripe number
+ *	N = H / U
+ *
+ * C - The component index coresponding to L
+ *
+ *	C = (H - (N * U)) / stripe_unit + G * D
+ *	[or (L % U) / stripe_unit + G * D]
+ *
+ * O - The component offset coresponding to L
+ *	O = L % stripe_unit + N * stripe_unit + M * group_depth * stripe_unit
+ *
+ * LCMdP – Parity cycle: Lowest Common Multiple of group_width, parity
+ *          divide by parity
+ *	LCMdP = lcm(group_width, parity) / parity
+ *
+ * R - The parity Rotation stripe
+ *     (Note parity cycle always starts at a group's boundary)
+ *	R = N % LCMdP
+ *
+ * I = the first parity device index
+ *	I = (group_width + group_width - R*parity - parity) % group_width
+ *
+ * Craid - The component index Rotated
+ *	Craid = (group_width + C - R*parity) % group_width
+ *      (We add the group_width to avoid negative numbers modulo math)
+ */
+void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,
+			  u64 length, struct ore_striping_info *si)
+{
+	u32	stripe_unit = layout->stripe_unit;
+	u32	group_width = layout->group_width;
+	u64	group_depth = layout->group_depth;
+	u32	parity      = layout->parity;
+
+	u32	D = group_width - parity;
+	u32	U = D * stripe_unit;
+	u64	T = U * group_depth;
+	u64	S = T * layout->group_count;
+	u64	M = div64_u64(file_offset, S);
+
+	/*
+	G = (L - (M * S)) / T
+	H = (L - (M * S)) % T
+	*/
+	u64	LmodS = file_offset - M * S;
+	u32	G = div64_u64(LmodS, T);
+	u64	H = LmodS - G * T;
+
+	u32	N = div_u64(H, U);
+	u32	Nlast;
+
+	/* "H - (N * U)" is just "H % U" so it's bound to u32 */
+	u32	C = (u32)(H - (N * U)) / stripe_unit + G * group_width;
+	u32 first_dev = C - C % group_width;
+
+	div_u64_rem(file_offset, stripe_unit, &si->unit_off);
+
+	si->obj_offset = si->unit_off + (N * stripe_unit) +
+				  (M * group_depth * stripe_unit);
+	si->cur_comp = C - first_dev;
+	si->cur_pg = si->unit_off / PAGE_SIZE;
+
+	if (parity) {
+		u32 LCMdP = lcm(group_width, parity) / parity;
+		/* R     = N % LCMdP; */
+		u32 RxP   = (N % LCMdP) * parity;
+
+		si->par_dev = (group_width + group_width - parity - RxP) %
+			      group_width + first_dev;
+		si->dev = (group_width + group_width + C - RxP) %
+			  group_width + first_dev;
+		si->bytes_in_stripe = U;
+		si->first_stripe_start = M * S + G * T + N * U;
+	} else {
+		/* Make the math correct see _prepare_one_group */
+		si->par_dev = group_width;
+		si->dev = C;
+	}
+
+	si->dev *= layout->mirrors_p1;
+	si->par_dev *= layout->mirrors_p1;
+	si->offset = file_offset;
+	si->length = T - H;
+	if (si->length > length)
+		si->length = length;
+
+	Nlast = div_u64(H + si->length + U - 1, U);
+	si->maxdevUnits = Nlast - N;
+
+	si->M = M;
+}
+EXPORT_SYMBOL(ore_calc_stripe_info);
+
+int _ore_add_stripe_unit(struct ore_io_state *ios,  unsigned *cur_pg,
+			 unsigned pgbase, struct page **pages,
+			 struct ore_per_dev_state *per_dev, int cur_len)
+{
+	unsigned pg = *cur_pg;
+	struct request_queue *q =
+			osd_request_queue(_ios_od(ios, per_dev->dev));
+	unsigned len = cur_len;
+	int ret;
+
+	if (per_dev->bio == NULL) {
+		unsigned bio_size;
+
+		if (!ios->reading) {
+			bio_size = ios->si.maxdevUnits;
+		} else {
+			bio_size = (ios->si.maxdevUnits + 1) *
+			     (ios->layout->group_width - ios->layout->parity) /
+			     ios->layout->group_width;
+		}
+		bio_size *= (ios->layout->stripe_unit / PAGE_SIZE);
+
+		per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
+		if (unlikely(!per_dev->bio)) {
+			ORE_DBGMSG("Failed to allocate BIO size=%u\n",
+				     bio_size);
+			ret = -ENOMEM;
+			goto out;
+		}
+	}
+
+	while (cur_len > 0) {
+		unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
+		unsigned added_len;
+
+		cur_len -= pglen;
+
+		added_len = bio_add_pc_page(q, per_dev->bio, pages[pg],
+					    pglen, pgbase);
+		if (unlikely(pglen != added_len)) {
+			/* If bi_vcnt == bi_max then this is a SW BUG */
+			ORE_DBGMSG("Failed bio_add_pc_page bi_vcnt=0x%x "
+				   "bi_max=0x%x BIO_MAX=0x%x cur_len=0x%x\n",
+				   per_dev->bio->bi_vcnt,
+				   per_dev->bio->bi_max_vecs,
+				   BIO_MAX_PAGES_KMALLOC, cur_len);
+			ret = -ENOMEM;
+			goto out;
+		}
+		_add_stripe_page(ios->sp2d, &ios->si, pages[pg]);
+
+		pgbase = 0;
+		++pg;
+	}
+	BUG_ON(cur_len);
+
+	per_dev->length += len;
+	*cur_pg = pg;
+	ret = 0;
+out:	/* we fail the complete unit on an error eg don't advance
+	 * per_dev->length and cur_pg. This means that we might have a bigger
+	 * bio than the CDB requested length (per_dev->length). That's fine
+	 * only the oposite is fatal.
+	 */
+	return ret;
+}
+
+static int _add_parity_units(struct ore_io_state *ios,
+			     struct ore_striping_info *si,
+			     unsigned dev, unsigned first_dev,
+			     unsigned mirrors_p1, unsigned devs_in_group,
+			     unsigned cur_len)
+{
+	unsigned do_parity;
+	int ret = 0;
+
+	for (do_parity = ios->layout->parity; do_parity; --do_parity) {
+		struct ore_per_dev_state *per_dev;
+
+		per_dev = &ios->per_dev[dev - first_dev];
+		if (!per_dev->length && !per_dev->offset) {
+			/* Only/always the parity unit of the first
+			 * stripe will be empty. So this is a chance to
+			 * initialize the per_dev info.
+			 */
+			per_dev->dev = dev;
+			per_dev->offset = si->obj_offset - si->unit_off;
+		}
+
+		ret = _ore_add_parity_unit(ios, si, per_dev, cur_len,
+					   do_parity == 1);
+		if (unlikely(ret))
+				break;
+
+		if (do_parity != 1) {
+			dev = ((dev + mirrors_p1) % devs_in_group) + first_dev;
+			si->cur_comp = (si->cur_comp + 1) %
+						       ios->layout->group_width;
+		}
+	}
+
+	return ret;
+}
+
+static int _prepare_for_striping(struct ore_io_state *ios)
+{
+	struct ore_striping_info *si = &ios->si;
+	unsigned stripe_unit = ios->layout->stripe_unit;
+	unsigned mirrors_p1 = ios->layout->mirrors_p1;
+	unsigned group_width = ios->layout->group_width;
+	unsigned devs_in_group = group_width * mirrors_p1;
+	unsigned dev = si->dev;
+	unsigned first_dev = dev - (dev % devs_in_group);
+	unsigned cur_pg = ios->pages_consumed;
+	u64 length = ios->length;
+	int ret = 0;
+
+	if (!ios->pages) {
+		ios->numdevs = ios->layout->mirrors_p1;
+		return 0;
+	}
+
+	BUG_ON(length > si->length);
+
+	while (length) {
+		struct ore_per_dev_state *per_dev =
+						&ios->per_dev[dev - first_dev];
+		unsigned cur_len, page_off = 0;
+
+		if (!per_dev->length && !per_dev->offset) {
+			/* First time initialize the per_dev info. */
+			per_dev->dev = dev;
+			if (dev == si->dev) {
+				WARN_ON(dev == si->par_dev);
+				per_dev->offset = si->obj_offset;
+				cur_len = stripe_unit - si->unit_off;
+				page_off = si->unit_off & ~PAGE_MASK;
+				BUG_ON(page_off && (page_off != ios->pgbase));
+			} else {
+				per_dev->offset = si->obj_offset - si->unit_off;
+				cur_len = stripe_unit;
+			}
+		} else {
+			cur_len = stripe_unit;
+		}
+		if (cur_len >= length)
+			cur_len = length;
+
+		ret = _ore_add_stripe_unit(ios, &cur_pg, page_off, ios->pages,
+					   per_dev, cur_len);
+		if (unlikely(ret))
+			goto out;
+
+		length -= cur_len;
+
+		dev = ((dev + mirrors_p1) % devs_in_group) + first_dev;
+		si->cur_comp = (si->cur_comp + 1) % group_width;
+		if (unlikely((dev == si->par_dev) || (!length && ios->sp2d))) {
+			if (!length && ios->sp2d) {
+				/* If we are writing and this is the very last
+				 * stripe. then operate on parity dev.
+				 */
+				dev = si->par_dev;
+				/* If last stripe operate on parity comp */
+				si->cur_comp = group_width - ios->layout->parity;
+			}
+
+			/* In writes cur_len just means if it's the
+			 * last one. See _ore_add_parity_unit.
+			 */
+			ret = _add_parity_units(ios, si, dev, first_dev,
+						mirrors_p1, devs_in_group,
+						ios->sp2d ? length : cur_len);
+			if (unlikely(ret))
+					goto out;
+
+			/* Rotate next par_dev backwards with wraping */
+			si->par_dev = (devs_in_group + si->par_dev -
+				       ios->layout->parity * mirrors_p1) %
+				      devs_in_group + first_dev;
+			/* Next stripe, start fresh */
+			si->cur_comp = 0;
+			si->cur_pg = 0;
+			si->obj_offset += cur_len;
+			si->unit_off = 0;
+		}
+	}
+out:
+	ios->numdevs = devs_in_group;
+	ios->pages_consumed = cur_pg;
+	return ret;
+}
+
+int ore_create(struct ore_io_state *ios)
+{
+	int i, ret;
+
+	for (i = 0; i < ios->oc->numdevs; i++) {
+		struct osd_request *or;
+
+		or = osd_start_request(_ios_od(ios, i));
+		if (unlikely(!or)) {
+			ORE_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		ios->per_dev[i].or = or;
+		ios->numdevs++;
+
+		osd_req_create_object(or, _ios_obj(ios, i));
+	}
+	ret = ore_io_execute(ios);
+
+out:
+	return ret;
+}
+EXPORT_SYMBOL(ore_create);
+
+int ore_remove(struct ore_io_state *ios)
+{
+	int i, ret;
+
+	for (i = 0; i < ios->oc->numdevs; i++) {
+		struct osd_request *or;
+
+		or = osd_start_request(_ios_od(ios, i));
+		if (unlikely(!or)) {
+			ORE_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		ios->per_dev[i].or = or;
+		ios->numdevs++;
+
+		osd_req_remove_object(or, _ios_obj(ios, i));
+	}
+	ret = ore_io_execute(ios);
+
+out:
+	return ret;
+}
+EXPORT_SYMBOL(ore_remove);
+
+static int _write_mirror(struct ore_io_state *ios, int cur_comp)
+{
+	struct ore_per_dev_state *master_dev = &ios->per_dev[cur_comp];
+	unsigned dev = ios->per_dev[cur_comp].dev;
+	unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
+	int ret = 0;
+
+	if (ios->pages && !master_dev->length)
+		return 0; /* Just an empty slot */
+
+	for (; cur_comp < last_comp; ++cur_comp, ++dev) {
+		struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
+		struct osd_request *or;
+
+		or = osd_start_request(_ios_od(ios, dev));
+		if (unlikely(!or)) {
+			ORE_ERR("%s: osd_start_request failed\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		per_dev->or = or;
+
+		if (ios->pages) {
+			struct bio *bio;
+
+			if (per_dev != master_dev) {
+				bio = bio_clone_fast(master_dev->bio,
+						     GFP_KERNEL, NULL);
+				if (unlikely(!bio)) {
+					ORE_DBGMSG(
+					      "Failed to allocate BIO size=%u\n",
+					      master_dev->bio->bi_max_vecs);
+					ret = -ENOMEM;
+					goto out;
+				}
+
+				bio->bi_disk = NULL;
+				bio->bi_next = NULL;
+				per_dev->offset = master_dev->offset;
+				per_dev->length = master_dev->length;
+				per_dev->bio =  bio;
+				per_dev->dev = dev;
+			} else {
+				bio = master_dev->bio;
+				/* FIXME: bio_set_dir() */
+				bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+			}
+
+			osd_req_write(or, _ios_obj(ios, cur_comp),
+				      per_dev->offset, bio, per_dev->length);
+			ORE_DBGMSG("write(0x%llx) offset=0x%llx "
+				      "length=0x%llx dev=%d\n",
+				     _LLU(_ios_obj(ios, cur_comp)->id),
+				     _LLU(per_dev->offset),
+				     _LLU(per_dev->length), dev);
+		} else if (ios->kern_buff) {
+			per_dev->offset = ios->si.obj_offset;
+			per_dev->dev = ios->si.dev + dev;
+
+			/* no cross device without page array */
+			BUG_ON((ios->layout->group_width > 1) &&
+			       (ios->si.unit_off + ios->length >
+				ios->layout->stripe_unit));
+
+			ret = osd_req_write_kern(or, _ios_obj(ios, cur_comp),
+						 per_dev->offset,
+						 ios->kern_buff, ios->length);
+			if (unlikely(ret))
+				goto out;
+			ORE_DBGMSG2("write_kern(0x%llx) offset=0x%llx "
+				      "length=0x%llx dev=%d\n",
+				     _LLU(_ios_obj(ios, cur_comp)->id),
+				     _LLU(per_dev->offset),
+				     _LLU(ios->length), per_dev->dev);
+		} else {
+			osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
+			ORE_DBGMSG2("obj(0x%llx) set_attributes=%d dev=%d\n",
+				     _LLU(_ios_obj(ios, cur_comp)->id),
+				     ios->out_attr_len, dev);
+		}
+
+		if (ios->out_attr)
+			osd_req_add_set_attr_list(or, ios->out_attr,
+						  ios->out_attr_len);
+
+		if (ios->in_attr)
+			osd_req_add_get_attr_list(or, ios->in_attr,
+						  ios->in_attr_len);
+	}
+
+out:
+	return ret;
+}
+
+int ore_write(struct ore_io_state *ios)
+{
+	int i;
+	int ret;
+
+	if (unlikely(ios->sp2d && !ios->r4w)) {
+		/* A library is attempting a RAID-write without providing
+		 * a pages lock interface.
+		 */
+		WARN_ON_ONCE(1);
+		return -ENOTSUPP;
+	}
+
+	ret = _prepare_for_striping(ios);
+	if (unlikely(ret))
+		return ret;
+
+	for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
+		ret = _write_mirror(ios, i);
+		if (unlikely(ret))
+			return ret;
+	}
+
+	ret = ore_io_execute(ios);
+	return ret;
+}
+EXPORT_SYMBOL(ore_write);
+
+int _ore_read_mirror(struct ore_io_state *ios, unsigned cur_comp)
+{
+	struct osd_request *or;
+	struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
+	struct osd_obj_id *obj = _ios_obj(ios, cur_comp);
+	unsigned first_dev = (unsigned)obj->id;
+
+	if (ios->pages && !per_dev->length)
+		return 0; /* Just an empty slot */
+
+	first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
+	or = osd_start_request(_ios_od(ios, first_dev));
+	if (unlikely(!or)) {
+		ORE_ERR("%s: osd_start_request failed\n", __func__);
+		return -ENOMEM;
+	}
+	per_dev->or = or;
+
+	if (ios->pages) {
+		if (per_dev->cur_sg) {
+			/* finalize the last sg_entry */
+			_ore_add_sg_seg(per_dev, 0, false);
+			if (unlikely(!per_dev->cur_sg))
+				return 0; /* Skip parity only device */
+
+			osd_req_read_sg(or, obj, per_dev->bio,
+					per_dev->sglist, per_dev->cur_sg);
+		} else {
+			/* The no raid case */
+			osd_req_read(or, obj, per_dev->offset,
+				     per_dev->bio, per_dev->length);
+		}
+
+		ORE_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
+			     " dev=%d sg_len=%d\n", _LLU(obj->id),
+			     _LLU(per_dev->offset), _LLU(per_dev->length),
+			     first_dev, per_dev->cur_sg);
+	} else {
+		BUG_ON(ios->kern_buff);
+
+		osd_req_get_attributes(or, obj);
+		ORE_DBGMSG2("obj(0x%llx) get_attributes=%d dev=%d\n",
+			      _LLU(obj->id),
+			      ios->in_attr_len, first_dev);
+	}
+	if (ios->out_attr)
+		osd_req_add_set_attr_list(or, ios->out_attr, ios->out_attr_len);
+
+	if (ios->in_attr)
+		osd_req_add_get_attr_list(or, ios->in_attr, ios->in_attr_len);
+
+	return 0;
+}
+
+int ore_read(struct ore_io_state *ios)
+{
+	int i;
+	int ret;
+
+	ret = _prepare_for_striping(ios);
+	if (unlikely(ret))
+		return ret;
+
+	for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
+		ret = _ore_read_mirror(ios, i);
+		if (unlikely(ret))
+			return ret;
+	}
+
+	ret = ore_io_execute(ios);
+	return ret;
+}
+EXPORT_SYMBOL(ore_read);
+
+int extract_attr_from_ios(struct ore_io_state *ios, struct osd_attr *attr)
+{
+	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
+	void *iter = NULL;
+	int nelem;
+
+	do {
+		nelem = 1;
+		osd_req_decode_get_attr_list(ios->per_dev[0].or,
+					     &cur_attr, &nelem, &iter);
+		if ((cur_attr.attr_page == attr->attr_page) &&
+		    (cur_attr.attr_id == attr->attr_id)) {
+			attr->len = cur_attr.len;
+			attr->val_ptr = cur_attr.val_ptr;
+			return 0;
+		}
+	} while (iter);
+
+	return -EIO;
+}
+EXPORT_SYMBOL(extract_attr_from_ios);
+
+static int _truncate_mirrors(struct ore_io_state *ios, unsigned cur_comp,
+			     struct osd_attr *attr)
+{
+	int last_comp = cur_comp + ios->layout->mirrors_p1;
+
+	for (; cur_comp < last_comp; ++cur_comp) {
+		struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
+		struct osd_request *or;
+
+		or = osd_start_request(_ios_od(ios, cur_comp));
+		if (unlikely(!or)) {
+			ORE_ERR("%s: osd_start_request failed\n", __func__);
+			return -ENOMEM;
+		}
+		per_dev->or = or;
+
+		osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
+		osd_req_add_set_attr_list(or, attr, 1);
+	}
+
+	return 0;
+}
+
+struct _trunc_info {
+	struct ore_striping_info si;
+	u64 prev_group_obj_off;
+	u64 next_group_obj_off;
+
+	unsigned first_group_dev;
+	unsigned nex_group_dev;
+};
+
+static void _calc_trunk_info(struct ore_layout *layout, u64 file_offset,
+			     struct _trunc_info *ti)
+{
+	unsigned stripe_unit = layout->stripe_unit;
+
+	ore_calc_stripe_info(layout, file_offset, 0, &ti->si);
+
+	ti->prev_group_obj_off = ti->si.M * stripe_unit;
+	ti->next_group_obj_off = ti->si.M ? (ti->si.M - 1) * stripe_unit : 0;
+
+	ti->first_group_dev = ti->si.dev - (ti->si.dev % layout->group_width);
+	ti->nex_group_dev = ti->first_group_dev + layout->group_width;
+}
+
+int ore_truncate(struct ore_layout *layout, struct ore_components *oc,
+		   u64 size)
+{
+	struct ore_io_state *ios;
+	struct exofs_trunc_attr {
+		struct osd_attr attr;
+		__be64 newsize;
+	} *size_attrs;
+	struct _trunc_info ti;
+	int i, ret;
+
+	ret = ore_get_io_state(layout, oc, &ios);
+	if (unlikely(ret))
+		return ret;
+
+	_calc_trunk_info(ios->layout, size, &ti);
+
+	size_attrs = kcalloc(ios->oc->numdevs, sizeof(*size_attrs),
+			     GFP_KERNEL);
+	if (unlikely(!size_attrs)) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ios->numdevs = ios->oc->numdevs;
+
+	for (i = 0; i < ios->numdevs; ++i) {
+		struct exofs_trunc_attr *size_attr = &size_attrs[i];
+		u64 obj_size;
+
+		if (i < ti.first_group_dev)
+			obj_size = ti.prev_group_obj_off;
+		else if (i >= ti.nex_group_dev)
+			obj_size = ti.next_group_obj_off;
+		else if (i < ti.si.dev) /* dev within this group */
+			obj_size = ti.si.obj_offset +
+				      ios->layout->stripe_unit - ti.si.unit_off;
+		else if (i == ti.si.dev)
+			obj_size = ti.si.obj_offset;
+		else /* i > ti.dev */
+			obj_size = ti.si.obj_offset - ti.si.unit_off;
+
+		size_attr->newsize = cpu_to_be64(obj_size);
+		size_attr->attr = g_attr_logical_length;
+		size_attr->attr.val_ptr = &size_attr->newsize;
+
+		ORE_DBGMSG2("trunc(0x%llx) obj_offset=0x%llx dev=%d\n",
+			     _LLU(oc->comps->obj.id), _LLU(obj_size), i);
+		ret = _truncate_mirrors(ios, i * ios->layout->mirrors_p1,
+					&size_attr->attr);
+		if (unlikely(ret))
+			goto out;
+	}
+	ret = ore_io_execute(ios);
+
+out:
+	kfree(size_attrs);
+	ore_put_io_state(ios);
+	return ret;
+}
+EXPORT_SYMBOL(ore_truncate);
+
+const struct osd_attr g_attr_logical_length = ATTR_DEF(
+	OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
+EXPORT_SYMBOL(g_attr_logical_length);
diff --git a/src/kernel/linux/v4.19/fs/exofs/ore_raid.c b/src/kernel/linux/v4.19/fs/exofs/ore_raid.c
new file mode 100644
index 0000000..199590f
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/ore_raid.c
@@ -0,0 +1,756 @@
+/*
+ * Copyright (C) 2011
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * This file is part of the objects raid engine (ore).
+ *
+ * It is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "ore". If not, write to the Free Software Foundation, Inc:
+ *	"Free Software Foundation <info@fsf.org>"
+ */
+
+#include <linux/gfp.h>
+#include <linux/async_tx.h>
+
+#include "ore_raid.h"
+
+#undef ORE_DBGMSG2
+#define ORE_DBGMSG2 ORE_DBGMSG
+
+static struct page *_raid_page_alloc(void)
+{
+	return alloc_page(GFP_KERNEL);
+}
+
+static void _raid_page_free(struct page *p)
+{
+	__free_page(p);
+}
+
+/* This struct is forward declare in ore_io_state, but is private to here.
+ * It is put on ios->sp2d for RAID5/6 writes only. See _gen_xor_unit.
+ *
+ * __stripe_pages_2d is a 2d array of pages, and it is also a corner turn.
+ * Ascending page index access is sp2d(p-minor, c-major). But storage is
+ * sp2d[p-minor][c-major], so it can be properlly presented to the async-xor
+ * API.
+ */
+struct __stripe_pages_2d {
+	/* Cache some hot path repeated calculations */
+	unsigned parity;
+	unsigned data_devs;
+	unsigned pages_in_unit;
+
+	bool needed ;
+
+	/* Array size is pages_in_unit (layout->stripe_unit / PAGE_SIZE) */
+	struct __1_page_stripe {
+		bool alloc;
+		unsigned write_count;
+		struct async_submit_ctl submit;
+		struct dma_async_tx_descriptor *tx;
+
+		/* The size of this array is data_devs + parity */
+		struct page **pages;
+		struct page **scribble;
+		/* bool array, size of this array is data_devs */
+		char *page_is_read;
+	} _1p_stripes[];
+};
+
+/* This can get bigger then a page. So support multiple page allocations
+ * _sp2d_free should be called even if _sp2d_alloc fails (by returning
+ * none-zero).
+ */
+static int _sp2d_alloc(unsigned pages_in_unit, unsigned group_width,
+		       unsigned parity, struct __stripe_pages_2d **psp2d)
+{
+	struct __stripe_pages_2d *sp2d;
+	unsigned data_devs = group_width - parity;
+
+	/*
+	 * Desired allocation layout is, though when larger than PAGE_SIZE,
+	 * each struct __alloc_1p_arrays is separately allocated:
+
+	struct _alloc_all_bytes {
+		struct __alloc_stripe_pages_2d {
+			struct __stripe_pages_2d sp2d;
+			struct __1_page_stripe _1p_stripes[pages_in_unit];
+		} __asp2d;
+		struct __alloc_1p_arrays {
+			struct page *pages[group_width];
+			struct page *scribble[group_width];
+			char page_is_read[data_devs];
+		} __a1pa[pages_in_unit];
+	} *_aab;
+
+	struct __alloc_1p_arrays *__a1pa;
+	struct __alloc_1p_arrays *__a1pa_end;
+
+	*/
+
+	char *__a1pa;
+	char *__a1pa_end;
+
+	const size_t sizeof_stripe_pages_2d =
+		sizeof(struct __stripe_pages_2d) +
+		sizeof(struct __1_page_stripe) * pages_in_unit;
+	const size_t sizeof__a1pa =
+		ALIGN(sizeof(struct page *) * (2 * group_width) + data_devs,
+		      sizeof(void *));
+	const size_t sizeof__a1pa_arrays = sizeof__a1pa * pages_in_unit;
+	const size_t alloc_total = sizeof_stripe_pages_2d +
+				   sizeof__a1pa_arrays;
+
+	unsigned num_a1pa, alloc_size, i;
+
+	/* FIXME: check these numbers in ore_verify_layout */
+	BUG_ON(sizeof_stripe_pages_2d > PAGE_SIZE);
+	BUG_ON(sizeof__a1pa > PAGE_SIZE);
+
+	/*
+	 * If alloc_total would be larger than PAGE_SIZE, only allocate
+	 * as many a1pa items as would fill the rest of the page, instead
+	 * of the full pages_in_unit count.
+	 */
+	if (alloc_total > PAGE_SIZE) {
+		num_a1pa = (PAGE_SIZE - sizeof_stripe_pages_2d) / sizeof__a1pa;
+		alloc_size = sizeof_stripe_pages_2d + sizeof__a1pa * num_a1pa;
+	} else {
+		num_a1pa = pages_in_unit;
+		alloc_size = alloc_total;
+	}
+
+	*psp2d = sp2d = kzalloc(alloc_size, GFP_KERNEL);
+	if (unlikely(!sp2d)) {
+		ORE_DBGMSG("!! Failed to alloc sp2d size=%d\n", alloc_size);
+		return -ENOMEM;
+	}
+	/* From here Just call _sp2d_free */
+
+	/* Find start of a1pa area. */
+	__a1pa = (char *)sp2d + sizeof_stripe_pages_2d;
+	/* Find end of the _allocated_ a1pa area. */
+	__a1pa_end = __a1pa + alloc_size;
+
+	/* Allocate additionally needed a1pa items in PAGE_SIZE chunks. */
+	for (i = 0; i < pages_in_unit; ++i) {
+		struct __1_page_stripe *stripe = &sp2d->_1p_stripes[i];
+
+		if (unlikely(__a1pa >= __a1pa_end)) {
+			num_a1pa = min_t(unsigned, PAGE_SIZE / sizeof__a1pa,
+							pages_in_unit - i);
+			alloc_size = sizeof__a1pa * num_a1pa;
+
+			__a1pa = kzalloc(alloc_size, GFP_KERNEL);
+			if (unlikely(!__a1pa)) {
+				ORE_DBGMSG("!! Failed to _alloc_1p_arrays=%d\n",
+					   num_a1pa);
+				return -ENOMEM;
+			}
+			__a1pa_end = __a1pa + alloc_size;
+			/* First *pages is marked for kfree of the buffer */
+			stripe->alloc = true;
+		}
+
+		/*
+		 * Attach all _lp_stripes pointers to the allocation for
+		 * it which was either part of the original PAGE_SIZE
+		 * allocation or the subsequent allocation in this loop.
+		 */
+		stripe->pages = (void *)__a1pa;
+		stripe->scribble = stripe->pages + group_width;
+		stripe->page_is_read = (char *)stripe->scribble + group_width;
+		__a1pa += sizeof__a1pa;
+	}
+
+	sp2d->parity = parity;
+	sp2d->data_devs = data_devs;
+	sp2d->pages_in_unit = pages_in_unit;
+	return 0;
+}
+
+static void _sp2d_reset(struct __stripe_pages_2d *sp2d,
+			const struct _ore_r4w_op *r4w, void *priv)
+{
+	unsigned data_devs = sp2d->data_devs;
+	unsigned group_width = data_devs + sp2d->parity;
+	int p, c;
+
+	if (!sp2d->needed)
+		return;
+
+	for (c = data_devs - 1; c >= 0; --c)
+		for (p = sp2d->pages_in_unit - 1; p >= 0; --p) {
+			struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+
+			if (_1ps->page_is_read[c]) {
+				struct page *page = _1ps->pages[c];
+
+				r4w->put_page(priv, page);
+				_1ps->page_is_read[c] = false;
+			}
+		}
+
+	for (p = 0; p < sp2d->pages_in_unit; p++) {
+		struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+
+		memset(_1ps->pages, 0, group_width * sizeof(*_1ps->pages));
+		_1ps->write_count = 0;
+		_1ps->tx = NULL;
+	}
+
+	sp2d->needed = false;
+}
+
+static void _sp2d_free(struct __stripe_pages_2d *sp2d)
+{
+	unsigned i;
+
+	if (!sp2d)
+		return;
+
+	for (i = 0; i < sp2d->pages_in_unit; ++i) {
+		if (sp2d->_1p_stripes[i].alloc)
+			kfree(sp2d->_1p_stripes[i].pages);
+	}
+
+	kfree(sp2d);
+}
+
+static unsigned _sp2d_min_pg(struct __stripe_pages_2d *sp2d)
+{
+	unsigned p;
+
+	for (p = 0; p < sp2d->pages_in_unit; p++) {
+		struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+
+		if (_1ps->write_count)
+			return p;
+	}
+
+	return ~0;
+}
+
+static unsigned _sp2d_max_pg(struct __stripe_pages_2d *sp2d)
+{
+	int p;
+
+	for (p = sp2d->pages_in_unit - 1; p >= 0; --p) {
+		struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+
+		if (_1ps->write_count)
+			return p;
+	}
+
+	return ~0;
+}
+
+static void _gen_xor_unit(struct __stripe_pages_2d *sp2d)
+{
+	unsigned p;
+	unsigned tx_flags = ASYNC_TX_ACK;
+
+	if (sp2d->parity == 1)
+		tx_flags |= ASYNC_TX_XOR_ZERO_DST;
+
+	for (p = 0; p < sp2d->pages_in_unit; p++) {
+		struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+
+		if (!_1ps->write_count)
+			continue;
+
+		init_async_submit(&_1ps->submit, tx_flags,
+			NULL, NULL, NULL, (addr_conv_t *)_1ps->scribble);
+
+		if (sp2d->parity == 1)
+			_1ps->tx = async_xor(_1ps->pages[sp2d->data_devs],
+						_1ps->pages, 0, sp2d->data_devs,
+						PAGE_SIZE, &_1ps->submit);
+		else /* parity == 2 */
+			_1ps->tx = async_gen_syndrome(_1ps->pages, 0,
+						sp2d->data_devs + sp2d->parity,
+						PAGE_SIZE, &_1ps->submit);
+	}
+
+	for (p = 0; p < sp2d->pages_in_unit; p++) {
+		struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+		/* NOTE: We wait for HW synchronously (I don't have such HW
+		 * to test with.) Is parallelism needed with today's multi
+		 * cores?
+		 */
+		async_tx_issue_pending(_1ps->tx);
+	}
+}
+
+void _ore_add_stripe_page(struct __stripe_pages_2d *sp2d,
+		       struct ore_striping_info *si, struct page *page)
+{
+	struct __1_page_stripe *_1ps;
+
+	sp2d->needed = true;
+
+	_1ps = &sp2d->_1p_stripes[si->cur_pg];
+	_1ps->pages[si->cur_comp] = page;
+	++_1ps->write_count;
+
+	si->cur_pg = (si->cur_pg + 1) % sp2d->pages_in_unit;
+	/* si->cur_comp is advanced outside at main loop */
+}
+
+void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len,
+		     bool not_last)
+{
+	struct osd_sg_entry *sge;
+
+	ORE_DBGMSG("dev=%d cur_len=0x%x not_last=%d cur_sg=%d "
+		     "offset=0x%llx length=0x%x last_sgs_total=0x%x\n",
+		     per_dev->dev, cur_len, not_last, per_dev->cur_sg,
+		     _LLU(per_dev->offset), per_dev->length,
+		     per_dev->last_sgs_total);
+
+	if (!per_dev->cur_sg) {
+		sge = per_dev->sglist;
+
+		/* First time we prepare two entries */
+		if (per_dev->length) {
+			++per_dev->cur_sg;
+			sge->offset = per_dev->offset;
+			sge->len = per_dev->length;
+		} else {
+			/* Here the parity is the first unit of this object.
+			 * This happens every time we reach a parity device on
+			 * the same stripe as the per_dev->offset. We need to
+			 * just skip this unit.
+			 */
+			per_dev->offset += cur_len;
+			return;
+		}
+	} else {
+		/* finalize the last one */
+		sge = &per_dev->sglist[per_dev->cur_sg - 1];
+		sge->len = per_dev->length - per_dev->last_sgs_total;
+	}
+
+	if (not_last) {
+		/* Partly prepare the next one */
+		struct osd_sg_entry *next_sge = sge + 1;
+
+		++per_dev->cur_sg;
+		next_sge->offset = sge->offset + sge->len + cur_len;
+		/* Save cur len so we know how mutch was added next time */
+		per_dev->last_sgs_total = per_dev->length;
+		next_sge->len = 0;
+	} else if (!sge->len) {
+		/* Optimize for when the last unit is a parity */
+		--per_dev->cur_sg;
+	}
+}
+
+static int _alloc_read_4_write(struct ore_io_state *ios)
+{
+	struct ore_layout *layout = ios->layout;
+	int ret;
+	/* We want to only read those pages not in cache so worst case
+	 * is a stripe populated with every other page
+	 */
+	unsigned sgs_per_dev = ios->sp2d->pages_in_unit + 2;
+
+	ret = _ore_get_io_state(layout, ios->oc,
+				layout->group_width * layout->mirrors_p1,
+				sgs_per_dev, 0, &ios->ios_read_4_write);
+	return ret;
+}
+
+/* @si contains info of the to-be-inserted page. Update of @si should be
+ * maintained by caller. Specificaly si->dev, si->obj_offset, ...
+ */
+static int _add_to_r4w(struct ore_io_state *ios, struct ore_striping_info *si,
+		       struct page *page, unsigned pg_len)
+{
+	struct request_queue *q;
+	struct ore_per_dev_state *per_dev;
+	struct ore_io_state *read_ios;
+	unsigned first_dev = si->dev - (si->dev %
+			  (ios->layout->group_width * ios->layout->mirrors_p1));
+	unsigned comp = si->dev - first_dev;
+	unsigned added_len;
+
+	if (!ios->ios_read_4_write) {
+		int ret = _alloc_read_4_write(ios);
+
+		if (unlikely(ret))
+			return ret;
+	}
+
+	read_ios = ios->ios_read_4_write;
+	read_ios->numdevs = ios->layout->group_width * ios->layout->mirrors_p1;
+
+	per_dev = &read_ios->per_dev[comp];
+	if (!per_dev->length) {
+		per_dev->bio = bio_kmalloc(GFP_KERNEL,
+					   ios->sp2d->pages_in_unit);
+		if (unlikely(!per_dev->bio)) {
+			ORE_DBGMSG("Failed to allocate BIO size=%u\n",
+				     ios->sp2d->pages_in_unit);
+			return -ENOMEM;
+		}
+		per_dev->offset = si->obj_offset;
+		per_dev->dev = si->dev;
+	} else if (si->obj_offset != (per_dev->offset + per_dev->length)) {
+		u64 gap = si->obj_offset - (per_dev->offset + per_dev->length);
+
+		_ore_add_sg_seg(per_dev, gap, true);
+	}
+	q = osd_request_queue(ore_comp_dev(read_ios->oc, per_dev->dev));
+	added_len = bio_add_pc_page(q, per_dev->bio, page, pg_len,
+				    si->obj_offset % PAGE_SIZE);
+	if (unlikely(added_len != pg_len)) {
+		ORE_DBGMSG("Failed to bio_add_pc_page bi_vcnt=%d\n",
+			      per_dev->bio->bi_vcnt);
+		return -ENOMEM;
+	}
+
+	per_dev->length += pg_len;
+	return 0;
+}
+
+/* read the beginning of an unaligned first page */
+static int _add_to_r4w_first_page(struct ore_io_state *ios, struct page *page)
+{
+	struct ore_striping_info si;
+	unsigned pg_len;
+
+	ore_calc_stripe_info(ios->layout, ios->offset, 0, &si);
+
+	pg_len = si.obj_offset % PAGE_SIZE;
+	si.obj_offset -= pg_len;
+
+	ORE_DBGMSG("offset=0x%llx len=0x%x index=0x%lx dev=%x\n",
+		   _LLU(si.obj_offset), pg_len, page->index, si.dev);
+
+	return _add_to_r4w(ios, &si, page, pg_len);
+}
+
+/* read the end of an incomplete last page */
+static int _add_to_r4w_last_page(struct ore_io_state *ios, u64 *offset)
+{
+	struct ore_striping_info si;
+	struct page *page;
+	unsigned pg_len, p, c;
+
+	ore_calc_stripe_info(ios->layout, *offset, 0, &si);
+
+	p = si.cur_pg;
+	c = si.cur_comp;
+	page = ios->sp2d->_1p_stripes[p].pages[c];
+
+	pg_len = PAGE_SIZE - (si.unit_off % PAGE_SIZE);
+	*offset += pg_len;
+
+	ORE_DBGMSG("p=%d, c=%d next-offset=0x%llx len=0x%x dev=%x par_dev=%d\n",
+		   p, c, _LLU(*offset), pg_len, si.dev, si.par_dev);
+
+	BUG_ON(!page);
+
+	return _add_to_r4w(ios, &si, page, pg_len);
+}
+
+static void _mark_read4write_pages_uptodate(struct ore_io_state *ios, int ret)
+{
+	struct bio_vec *bv;
+	unsigned i, d;
+
+	/* loop on all devices all pages */
+	for (d = 0; d < ios->numdevs; d++) {
+		struct bio *bio = ios->per_dev[d].bio;
+
+		if (!bio)
+			continue;
+
+		bio_for_each_segment_all(bv, bio, i) {
+			struct page *page = bv->bv_page;
+
+			SetPageUptodate(page);
+			if (PageError(page))
+				ClearPageError(page);
+		}
+	}
+}
+
+/* read_4_write is hacked to read the start of the first stripe and/or
+ * the end of the last stripe. If needed, with an sg-gap at each device/page.
+ * It is assumed to be called after the to_be_written pages of the first stripe
+ * are populating ios->sp2d[][]
+ *
+ * NOTE: We call ios->r4w->lock_fn for all pages needed for parity calculations
+ * These pages are held at sp2d[p].pages[c] but with
+ * sp2d[p].page_is_read[c] = true. At _sp2d_reset these pages are
+ * ios->r4w->lock_fn(). The ios->r4w->lock_fn might signal that the page is
+ * @uptodate=true, so we don't need to read it, only unlock, after IO.
+ *
+ * TODO: The read_4_write should calc a need_to_read_pages_count, if bigger then
+ * to-be-written count, we should consider the xor-in-place mode.
+ * need_to_read_pages_count is the actual number of pages not present in cache.
+ * maybe "devs_in_group - ios->sp2d[p].write_count" is a good enough
+ * approximation? In this mode the read pages are put in the empty places of
+ * ios->sp2d[p][*], xor is calculated the same way. These pages are
+ * allocated/freed and don't go through cache
+ */
+static int _read_4_write_first_stripe(struct ore_io_state *ios)
+{
+	struct ore_striping_info read_si;
+	struct __stripe_pages_2d *sp2d = ios->sp2d;
+	u64 offset = ios->si.first_stripe_start;
+	unsigned c, p, min_p = sp2d->pages_in_unit, max_p = -1;
+
+	if (offset == ios->offset) /* Go to start collect $200 */
+		goto read_last_stripe;
+
+	min_p = _sp2d_min_pg(sp2d);
+	max_p = _sp2d_max_pg(sp2d);
+
+	ORE_DBGMSG("stripe_start=0x%llx ios->offset=0x%llx min_p=%d max_p=%d\n",
+		   offset, ios->offset, min_p, max_p);
+
+	for (c = 0; ; c++) {
+		ore_calc_stripe_info(ios->layout, offset, 0, &read_si);
+		read_si.obj_offset += min_p * PAGE_SIZE;
+		offset += min_p * PAGE_SIZE;
+		for (p = min_p; p <= max_p; p++) {
+			struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+			struct page **pp = &_1ps->pages[c];
+			bool uptodate;
+
+			if (*pp) {
+				if (ios->offset % PAGE_SIZE)
+					/* Read the remainder of the page */
+					_add_to_r4w_first_page(ios, *pp);
+				/* to-be-written pages start here */
+				goto read_last_stripe;
+			}
+
+			*pp = ios->r4w->get_page(ios->private, offset,
+						 &uptodate);
+			if (unlikely(!*pp))
+				return -ENOMEM;
+
+			if (!uptodate)
+				_add_to_r4w(ios, &read_si, *pp, PAGE_SIZE);
+
+			/* Mark read-pages to be cache_released */
+			_1ps->page_is_read[c] = true;
+			read_si.obj_offset += PAGE_SIZE;
+			offset += PAGE_SIZE;
+		}
+		offset += (sp2d->pages_in_unit - p) * PAGE_SIZE;
+	}
+
+read_last_stripe:
+	return 0;
+}
+
+static int _read_4_write_last_stripe(struct ore_io_state *ios)
+{
+	struct ore_striping_info read_si;
+	struct __stripe_pages_2d *sp2d = ios->sp2d;
+	u64 offset;
+	u64 last_stripe_end;
+	unsigned bytes_in_stripe = ios->si.bytes_in_stripe;
+	unsigned c, p, min_p = sp2d->pages_in_unit, max_p = -1;
+
+	offset = ios->offset + ios->length;
+	if (offset % PAGE_SIZE)
+		_add_to_r4w_last_page(ios, &offset);
+		/* offset will be aligned to next page */
+
+	last_stripe_end = div_u64(offset + bytes_in_stripe - 1, bytes_in_stripe)
+				 * bytes_in_stripe;
+	if (offset == last_stripe_end) /* Optimize for the aligned case */
+		goto read_it;
+
+	ore_calc_stripe_info(ios->layout, offset, 0, &read_si);
+	p = read_si.cur_pg;
+	c = read_si.cur_comp;
+
+	if (min_p == sp2d->pages_in_unit) {
+		/* Didn't do it yet */
+		min_p = _sp2d_min_pg(sp2d);
+		max_p = _sp2d_max_pg(sp2d);
+	}
+
+	ORE_DBGMSG("offset=0x%llx stripe_end=0x%llx min_p=%d max_p=%d\n",
+		   offset, last_stripe_end, min_p, max_p);
+
+	while (offset < last_stripe_end) {
+		struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
+
+		if ((min_p <= p) && (p <= max_p)) {
+			struct page *page;
+			bool uptodate;
+
+			BUG_ON(_1ps->pages[c]);
+			page = ios->r4w->get_page(ios->private, offset,
+						  &uptodate);
+			if (unlikely(!page))
+				return -ENOMEM;
+
+			_1ps->pages[c] = page;
+			/* Mark read-pages to be cache_released */
+			_1ps->page_is_read[c] = true;
+			if (!uptodate)
+				_add_to_r4w(ios, &read_si, page, PAGE_SIZE);
+		}
+
+		offset += PAGE_SIZE;
+		if (p == (sp2d->pages_in_unit - 1)) {
+			++c;
+			p = 0;
+			ore_calc_stripe_info(ios->layout, offset, 0, &read_si);
+		} else {
+			read_si.obj_offset += PAGE_SIZE;
+			++p;
+		}
+	}
+
+read_it:
+	return 0;
+}
+
+static int _read_4_write_execute(struct ore_io_state *ios)
+{
+	struct ore_io_state *ios_read;
+	unsigned i;
+	int ret;
+
+	ios_read = ios->ios_read_4_write;
+	if (!ios_read)
+		return 0;
+
+	/* FIXME: Ugly to signal _sbi_read_mirror that we have bio(s). Change
+	 * to check for per_dev->bio
+	 */
+	ios_read->pages = ios->pages;
+
+	/* Now read these devices */
+	for (i = 0; i < ios_read->numdevs; i += ios_read->layout->mirrors_p1) {
+		ret = _ore_read_mirror(ios_read, i);
+		if (unlikely(ret))
+			return ret;
+	}
+
+	ret = ore_io_execute(ios_read); /* Synchronus execution */
+	if (unlikely(ret)) {
+		ORE_DBGMSG("!! ore_io_execute => %d\n", ret);
+		return ret;
+	}
+
+	_mark_read4write_pages_uptodate(ios_read, ret);
+	ore_put_io_state(ios_read);
+	ios->ios_read_4_write = NULL; /* Might need a reuse at last stripe */
+	return 0;
+}
+
+/* In writes @cur_len means length left. .i.e cur_len==0 is the last parity U */
+int _ore_add_parity_unit(struct ore_io_state *ios,
+			    struct ore_striping_info *si,
+			    struct ore_per_dev_state *per_dev,
+			    unsigned cur_len, bool do_xor)
+{
+	if (ios->reading) {
+		if (per_dev->cur_sg >= ios->sgs_per_dev) {
+			ORE_DBGMSG("cur_sg(%d) >= sgs_per_dev(%d)\n" ,
+				per_dev->cur_sg, ios->sgs_per_dev);
+			return -ENOMEM;
+		}
+		_ore_add_sg_seg(per_dev, cur_len, true);
+	} else {
+		struct __stripe_pages_2d *sp2d = ios->sp2d;
+		struct page **pages = ios->parity_pages + ios->cur_par_page;
+		unsigned num_pages;
+		unsigned array_start = 0;
+		unsigned i;
+		int ret;
+
+		si->cur_pg = _sp2d_min_pg(sp2d);
+		num_pages  = _sp2d_max_pg(sp2d) + 1 - si->cur_pg;
+
+		if (!per_dev->length) {
+			per_dev->offset += si->cur_pg * PAGE_SIZE;
+			/* If first stripe, Read in all read4write pages
+			 * (if needed) before we calculate the first parity.
+			 */
+			if (do_xor)
+				_read_4_write_first_stripe(ios);
+		}
+		if (!cur_len && do_xor)
+			/* If last stripe r4w pages of last stripe */
+			_read_4_write_last_stripe(ios);
+		_read_4_write_execute(ios);
+
+		for (i = 0; i < num_pages; i++) {
+			pages[i] = _raid_page_alloc();
+			if (unlikely(!pages[i]))
+				return -ENOMEM;
+
+			++(ios->cur_par_page);
+		}
+
+		BUG_ON(si->cur_comp < sp2d->data_devs);
+		BUG_ON(si->cur_pg + num_pages > sp2d->pages_in_unit);
+
+		ret = _ore_add_stripe_unit(ios,  &array_start, 0, pages,
+					   per_dev, num_pages * PAGE_SIZE);
+		if (unlikely(ret))
+			return ret;
+
+		if (do_xor) {
+			_gen_xor_unit(sp2d);
+			_sp2d_reset(sp2d, ios->r4w, ios->private);
+		}
+	}
+	return 0;
+}
+
+int _ore_post_alloc_raid_stuff(struct ore_io_state *ios)
+{
+	if (ios->parity_pages) {
+		struct ore_layout *layout = ios->layout;
+		unsigned pages_in_unit = layout->stripe_unit / PAGE_SIZE;
+
+		if (_sp2d_alloc(pages_in_unit, layout->group_width,
+				layout->parity, &ios->sp2d)) {
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+void _ore_free_raid_stuff(struct ore_io_state *ios)
+{
+	if (ios->sp2d) { /* writing and raid */
+		unsigned i;
+
+		for (i = 0; i < ios->cur_par_page; i++) {
+			struct page *page = ios->parity_pages[i];
+
+			if (page)
+				_raid_page_free(page);
+		}
+		if (ios->extra_part_alloc)
+			kfree(ios->parity_pages);
+		/* If IO returned an error pages might need unlocking */
+		_sp2d_reset(ios->sp2d, ios->r4w, ios->private);
+		_sp2d_free(ios->sp2d);
+	} else {
+		/* Will only be set if raid reading && sglist is big */
+		if (ios->extra_part_alloc)
+			kfree(ios->per_dev[0].sglist);
+	}
+	if (ios->ios_read_4_write)
+		ore_put_io_state(ios->ios_read_4_write);
+}
diff --git a/src/kernel/linux/v4.19/fs/exofs/ore_raid.h b/src/kernel/linux/v4.19/fs/exofs/ore_raid.h
new file mode 100644
index 0000000..a6e7467
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/ore_raid.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) from 2011
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * This file is part of the objects raid engine (ore).
+ *
+ * It is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "ore". If not, write to the Free Software Foundation, Inc:
+ *	"Free Software Foundation <info@fsf.org>"
+ */
+
+#include <scsi/osd_ore.h>
+
+#define ORE_ERR(fmt, a...) printk(KERN_ERR "ore: " fmt, ##a)
+
+#ifdef CONFIG_EXOFS_DEBUG
+#define ORE_DBGMSG(fmt, a...) \
+	printk(KERN_NOTICE "ore @%s:%d: " fmt, __func__, __LINE__, ##a)
+#else
+#define ORE_DBGMSG(fmt, a...) \
+	do { if (0) printk(fmt, ##a); } while (0)
+#endif
+
+/* u64 has problems with printk this will cast it to unsigned long long */
+#define _LLU(x) (unsigned long long)(x)
+
+#define ORE_DBGMSG2(M...) do {} while (0)
+/* #define ORE_DBGMSG2 ORE_DBGMSG */
+
+/* ios_raid.c stuff needed by ios.c */
+int _ore_post_alloc_raid_stuff(struct ore_io_state *ios);
+void _ore_free_raid_stuff(struct ore_io_state *ios);
+
+void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len,
+		 bool not_last);
+int _ore_add_parity_unit(struct ore_io_state *ios, struct ore_striping_info *si,
+		     struct ore_per_dev_state *per_dev, unsigned cur_len,
+		     bool do_xor);
+void _ore_add_stripe_page(struct __stripe_pages_2d *sp2d,
+		       struct ore_striping_info *si, struct page *page);
+static inline void _add_stripe_page(struct __stripe_pages_2d *sp2d,
+				struct ore_striping_info *si, struct page *page)
+{
+	if (!sp2d) /* Inline the fast path */
+		return; /* Hay no raid stuff */
+	_ore_add_stripe_page(sp2d, si, page);
+}
+
+/* ios.c stuff needed by ios_raid.c */
+int  _ore_get_io_state(struct ore_layout *layout,
+			struct ore_components *oc, unsigned numdevs,
+			unsigned sgs_per_dev, unsigned num_par_pages,
+			struct ore_io_state **pios);
+int _ore_add_stripe_unit(struct ore_io_state *ios,  unsigned *cur_pg,
+		unsigned pgbase, struct page **pages,
+		struct ore_per_dev_state *per_dev, int cur_len);
+int _ore_read_mirror(struct ore_io_state *ios, unsigned cur_comp);
+int ore_io_execute(struct ore_io_state *ios);
diff --git a/src/kernel/linux/v4.19/fs/exofs/super.c b/src/kernel/linux/v4.19/fs/exofs/super.c
new file mode 100644
index 0000000..8fb98bb
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/super.c
@@ -0,0 +1,1071 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com)
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     Copyright (C) 1992, 1993, 1994, 1995
+ *     Remy Card (card@masi.ibp.fr)
+ *     Laboratoire MASI - Institut Blaise Pascal
+ *     Universite Pierre et Marie Curie (Paris VI)
+ *     from
+ *     linux/fs/minix/inode.c
+ *     Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/string.h>
+#include <linux/parser.h>
+#include <linux/vfs.h>
+#include <linux/random.h>
+#include <linux/module.h>
+#include <linux/exportfs.h>
+#include <linux/slab.h>
+#include <linux/iversion.h>
+
+#include "exofs.h"
+
+#define EXOFS_DBGMSG2(M...) do {} while (0)
+
+/******************************************************************************
+ * MOUNT OPTIONS
+ *****************************************************************************/
+
+/*
+ * struct to hold what we get from mount options
+ */
+struct exofs_mountopt {
+	bool is_osdname;
+	const char *dev_name;
+	uint64_t pid;
+	int timeout;
+};
+
+/*
+ * exofs-specific mount-time options.
+ */
+enum { Opt_name, Opt_pid, Opt_to, Opt_err };
+
+/*
+ * Our mount-time options.  These should ideally be 64-bit unsigned, but the
+ * kernel's parsing functions do not currently support that.  32-bit should be
+ * sufficient for most applications now.
+ */
+static match_table_t tokens = {
+	{Opt_name, "osdname=%s"},
+	{Opt_pid, "pid=%u"},
+	{Opt_to, "to=%u"},
+	{Opt_err, NULL}
+};
+
+/*
+ * The main option parsing method.  Also makes sure that all of the mandatory
+ * mount options were set.
+ */
+static int parse_options(char *options, struct exofs_mountopt *opts)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	bool s_pid = false;
+
+	EXOFS_DBGMSG("parse_options %s\n", options);
+	/* defaults */
+	memset(opts, 0, sizeof(*opts));
+	opts->timeout = BLK_DEFAULT_SG_TIMEOUT;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		char str[32];
+
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_name:
+			kfree(opts->dev_name);
+			opts->dev_name = match_strdup(&args[0]);
+			if (unlikely(!opts->dev_name)) {
+				EXOFS_ERR("Error allocating dev_name");
+				return -ENOMEM;
+			}
+			opts->is_osdname = true;
+			break;
+		case Opt_pid:
+			if (0 == match_strlcpy(str, &args[0], sizeof(str)))
+				return -EINVAL;
+			opts->pid = simple_strtoull(str, NULL, 0);
+			if (opts->pid < EXOFS_MIN_PID) {
+				EXOFS_ERR("Partition ID must be >= %u",
+					  EXOFS_MIN_PID);
+				return -EINVAL;
+			}
+			s_pid = 1;
+			break;
+		case Opt_to:
+			if (match_int(&args[0], &option))
+				return -EINVAL;
+			if (option <= 0) {
+				EXOFS_ERR("Timeout must be > 0");
+				return -EINVAL;
+			}
+			opts->timeout = option * HZ;
+			break;
+		}
+	}
+
+	if (!s_pid) {
+		EXOFS_ERR("Need to specify the following options:\n");
+		EXOFS_ERR("    -o pid=pid_no_to_use\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/******************************************************************************
+ * INODE CACHE
+ *****************************************************************************/
+
+/*
+ * Our inode cache.  Isn't it pretty?
+ */
+static struct kmem_cache *exofs_inode_cachep;
+
+/*
+ * Allocate an inode in the cache
+ */
+static struct inode *exofs_alloc_inode(struct super_block *sb)
+{
+	struct exofs_i_info *oi;
+
+	oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL);
+	if (!oi)
+		return NULL;
+
+	inode_set_iversion(&oi->vfs_inode, 1);
+	return &oi->vfs_inode;
+}
+
+static void exofs_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kmem_cache_free(exofs_inode_cachep, exofs_i(inode));
+}
+
+/*
+ * Remove an inode from the cache
+ */
+static void exofs_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, exofs_i_callback);
+}
+
+/*
+ * Initialize the inode
+ */
+static void exofs_init_once(void *foo)
+{
+	struct exofs_i_info *oi = foo;
+
+	inode_init_once(&oi->vfs_inode);
+}
+
+/*
+ * Create and initialize the inode cache
+ */
+static int init_inodecache(void)
+{
+	exofs_inode_cachep = kmem_cache_create_usercopy("exofs_inode_cache",
+				sizeof(struct exofs_i_info), 0,
+				SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD |
+				SLAB_ACCOUNT,
+				offsetof(struct exofs_i_info, i_data),
+				sizeof_field(struct exofs_i_info, i_data),
+				exofs_init_once);
+	if (exofs_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+/*
+ * Destroy the inode cache
+ */
+static void destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(exofs_inode_cachep);
+}
+
+/******************************************************************************
+ * Some osd helpers
+ *****************************************************************************/
+void exofs_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj)
+{
+	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
+}
+
+static int exofs_read_kern(struct osd_dev *od, u8 *cred, struct osd_obj_id *obj,
+		    u64 offset, void *p, unsigned length)
+{
+	struct osd_request *or = osd_start_request(od);
+/*	struct osd_sense_info osi = {.key = 0};*/
+	int ret;
+
+	if (unlikely(!or)) {
+		EXOFS_DBGMSG("%s: osd_start_request failed.\n", __func__);
+		return -ENOMEM;
+	}
+	ret = osd_req_read_kern(or, obj, offset, p, length);
+	if (unlikely(ret)) {
+		EXOFS_DBGMSG("%s: osd_req_read_kern failed.\n", __func__);
+		goto out;
+	}
+
+	ret = osd_finalize_request(or, 0, cred, NULL);
+	if (unlikely(ret)) {
+		EXOFS_DBGMSG("Failed to osd_finalize_request() => %d\n", ret);
+		goto out;
+	}
+
+	ret = osd_execute_request(or);
+	if (unlikely(ret))
+		EXOFS_DBGMSG("osd_execute_request() => %d\n", ret);
+	/* osd_req_decode_sense(or, ret); */
+
+out:
+	osd_end_request(or);
+	EXOFS_DBGMSG2("read_kern(0x%llx) offset=0x%llx "
+		      "length=0x%llx dev=%p ret=>%d\n",
+		      _LLU(obj->id), _LLU(offset), _LLU(length), od, ret);
+	return ret;
+}
+
+static const struct osd_attr g_attr_sb_stats = ATTR_DEF(
+	EXOFS_APAGE_SB_DATA,
+	EXOFS_ATTR_SB_STATS,
+	sizeof(struct exofs_sb_stats));
+
+static int __sbi_read_stats(struct exofs_sb_info *sbi)
+{
+	struct osd_attr attrs[] = {
+		[0] = g_attr_sb_stats,
+	};
+	struct ore_io_state *ios;
+	int ret;
+
+	ret = ore_get_io_state(&sbi->layout, &sbi->oc, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: ore_get_io_state failed.\n", __func__);
+		return ret;
+	}
+
+	ios->in_attr = attrs;
+	ios->in_attr_len = ARRAY_SIZE(attrs);
+
+	ret = ore_read(ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("Error reading super_block stats => %d\n", ret);
+		goto out;
+	}
+
+	ret = extract_attr_from_ios(ios, &attrs[0]);
+	if (ret) {
+		EXOFS_ERR("%s: extract_attr of sb_stats failed\n", __func__);
+		goto out;
+	}
+	if (attrs[0].len) {
+		struct exofs_sb_stats *ess;
+
+		if (unlikely(attrs[0].len != sizeof(*ess))) {
+			EXOFS_ERR("%s: Wrong version of exofs_sb_stats "
+				  "size(%d) != expected(%zd)\n",
+				  __func__, attrs[0].len, sizeof(*ess));
+			goto out;
+		}
+
+		ess = attrs[0].val_ptr;
+		sbi->s_nextid = le64_to_cpu(ess->s_nextid);
+		sbi->s_numfiles = le32_to_cpu(ess->s_numfiles);
+	}
+
+out:
+	ore_put_io_state(ios);
+	return ret;
+}
+
+static void stats_done(struct ore_io_state *ios, void *p)
+{
+	ore_put_io_state(ios);
+	/* Good thanks nothing to do anymore */
+}
+
+/* Asynchronously write the stats attribute */
+int exofs_sbi_write_stats(struct exofs_sb_info *sbi)
+{
+	struct osd_attr attrs[] = {
+		[0] = g_attr_sb_stats,
+	};
+	struct ore_io_state *ios;
+	int ret;
+
+	ret = ore_get_io_state(&sbi->layout, &sbi->oc, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: ore_get_io_state failed.\n", __func__);
+		return ret;
+	}
+
+	sbi->s_ess.s_nextid   = cpu_to_le64(sbi->s_nextid);
+	sbi->s_ess.s_numfiles = cpu_to_le64(sbi->s_numfiles);
+	attrs[0].val_ptr = &sbi->s_ess;
+
+
+	ios->done = stats_done;
+	ios->private = sbi;
+	ios->out_attr = attrs;
+	ios->out_attr_len = ARRAY_SIZE(attrs);
+
+	ret = ore_write(ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: ore_write failed.\n", __func__);
+		ore_put_io_state(ios);
+	}
+
+	return ret;
+}
+
+/******************************************************************************
+ * SUPERBLOCK FUNCTIONS
+ *****************************************************************************/
+static const struct super_operations exofs_sops;
+static const struct export_operations exofs_export_ops;
+
+/*
+ * Write the superblock to the OSD
+ */
+static int exofs_sync_fs(struct super_block *sb, int wait)
+{
+	struct exofs_sb_info *sbi;
+	struct exofs_fscb *fscb;
+	struct ore_comp one_comp;
+	struct ore_components oc;
+	struct ore_io_state *ios;
+	int ret = -ENOMEM;
+
+	fscb = kmalloc(sizeof(*fscb), GFP_KERNEL);
+	if (unlikely(!fscb))
+		return -ENOMEM;
+
+	sbi = sb->s_fs_info;
+
+	/* NOTE: We no longer dirty the super_block anywhere in exofs. The
+	 * reason we write the fscb here on unmount is so we can stay backwards
+	 * compatible with fscb->s_version == 1. (What we are not compatible
+	 * with is if a new version FS crashed and then we try to mount an old
+	 * version). Otherwise the exofs_fscb is read-only from mkfs time. All
+	 * the writeable info is set in exofs_sbi_write_stats() above.
+	 */
+
+	exofs_init_comps(&oc, &one_comp, sbi, EXOFS_SUPER_ID);
+
+	ret = ore_get_io_state(&sbi->layout, &oc, &ios);
+	if (unlikely(ret))
+		goto out;
+
+	ios->length = offsetof(struct exofs_fscb, s_dev_table_oid);
+	memset(fscb, 0, ios->length);
+	fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
+	fscb->s_numfiles = cpu_to_le64(sbi->s_numfiles);
+	fscb->s_magic = cpu_to_le16(sb->s_magic);
+	fscb->s_newfs = 0;
+	fscb->s_version = EXOFS_FSCB_VER;
+
+	ios->offset = 0;
+	ios->kern_buff = fscb;
+
+	ret = ore_write(ios);
+	if (unlikely(ret))
+		EXOFS_ERR("%s: ore_write failed.\n", __func__);
+
+out:
+	EXOFS_DBGMSG("s_nextid=0x%llx ret=%d\n", _LLU(sbi->s_nextid), ret);
+	ore_put_io_state(ios);
+	kfree(fscb);
+	return ret;
+}
+
+static void _exofs_print_device(const char *msg, const char *dev_path,
+				struct osd_dev *od, u64 pid)
+{
+	const struct osd_dev_info *odi = osduld_device_info(od);
+
+	printk(KERN_NOTICE "exofs: %s %s osd_name-%s pid-0x%llx\n",
+		msg, dev_path ?: "", odi->osdname, _LLU(pid));
+}
+
+static void exofs_free_sbi(struct exofs_sb_info *sbi)
+{
+	unsigned numdevs = sbi->oc.numdevs;
+
+	while (numdevs) {
+		unsigned i = --numdevs;
+		struct osd_dev *od = ore_comp_dev(&sbi->oc, i);
+
+		if (od) {
+			ore_comp_set_dev(&sbi->oc, i, NULL);
+			osduld_put_device(od);
+		}
+	}
+	kfree(sbi->oc.ods);
+	kfree(sbi);
+}
+
+/*
+ * This function is called when the vfs is freeing the superblock.  We just
+ * need to free our own part.
+ */
+static void exofs_put_super(struct super_block *sb)
+{
+	int num_pend;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+
+	/* make sure there are no pending commands */
+	for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
+	     num_pend = atomic_read(&sbi->s_curr_pending)) {
+		wait_queue_head_t wq;
+
+		printk(KERN_NOTICE "%s: !!Pending operations in flight. "
+		       "This is a BUG. please report to osd-dev@open-osd.org\n",
+		       __func__);
+		init_waitqueue_head(&wq);
+		wait_event_timeout(wq,
+				  (atomic_read(&sbi->s_curr_pending) == 0),
+				  msecs_to_jiffies(100));
+	}
+
+	_exofs_print_device("Unmounting", NULL, ore_comp_dev(&sbi->oc, 0),
+			    sbi->one_comp.obj.partition);
+
+	exofs_sysfs_sb_del(sbi);
+	exofs_free_sbi(sbi);
+	sb->s_fs_info = NULL;
+}
+
+static int _read_and_match_data_map(struct exofs_sb_info *sbi, unsigned numdevs,
+				    struct exofs_device_table *dt)
+{
+	int ret;
+
+	sbi->layout.stripe_unit =
+				le64_to_cpu(dt->dt_data_map.cb_stripe_unit);
+	sbi->layout.group_width =
+				le32_to_cpu(dt->dt_data_map.cb_group_width);
+	sbi->layout.group_depth =
+				le32_to_cpu(dt->dt_data_map.cb_group_depth);
+	sbi->layout.mirrors_p1  =
+				le32_to_cpu(dt->dt_data_map.cb_mirror_cnt) + 1;
+	sbi->layout.raid_algorithm  =
+				le32_to_cpu(dt->dt_data_map.cb_raid_algorithm);
+
+	ret = ore_verify_layout(numdevs, &sbi->layout);
+
+	EXOFS_DBGMSG("exofs: layout: "
+		"num_comps=%u stripe_unit=0x%x group_width=%u "
+		"group_depth=0x%llx mirrors_p1=%u raid_algorithm=%u\n",
+		numdevs,
+		sbi->layout.stripe_unit,
+		sbi->layout.group_width,
+		_LLU(sbi->layout.group_depth),
+		sbi->layout.mirrors_p1,
+		sbi->layout.raid_algorithm);
+	return ret;
+}
+
+static unsigned __ra_pages(struct ore_layout *layout)
+{
+	const unsigned _MIN_RA = 32; /* min 128K read-ahead */
+	unsigned ra_pages = layout->group_width * layout->stripe_unit /
+				PAGE_SIZE;
+	unsigned max_io_pages = exofs_max_io_pages(layout, ~0);
+
+	ra_pages *= 2; /* two stripes */
+	if (ra_pages < _MIN_RA)
+		ra_pages = roundup(_MIN_RA, ra_pages / 2);
+
+	if (ra_pages > max_io_pages)
+		ra_pages = max_io_pages;
+
+	return ra_pages;
+}
+
+/* @odi is valid only as long as @fscb_dev is valid */
+static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev,
+			     struct osd_dev_info *odi)
+{
+	odi->systemid_len = le32_to_cpu(dt_dev->systemid_len);
+	if (likely(odi->systemid_len))
+		memcpy(odi->systemid, dt_dev->systemid, OSD_SYSTEMID_LEN);
+
+	odi->osdname_len = le32_to_cpu(dt_dev->osdname_len);
+	odi->osdname = dt_dev->osdname;
+
+	/* FIXME support long names. Will need a _put function */
+	if (dt_dev->long_name_offset)
+		return -EINVAL;
+
+	/* Make sure osdname is printable!
+	 * mkexofs should give us space for a null-terminator else the
+	 * device-table is invalid.
+	 */
+	if (unlikely(odi->osdname_len >= sizeof(dt_dev->osdname)))
+		odi->osdname_len = sizeof(dt_dev->osdname) - 1;
+	dt_dev->osdname[odi->osdname_len] = 0;
+
+	/* If it's all zeros something is bad we read past end-of-obj */
+	return !(odi->systemid_len || odi->osdname_len);
+}
+
+static int __alloc_dev_table(struct exofs_sb_info *sbi, unsigned numdevs,
+		      struct exofs_dev **peds)
+{
+	/* Twice bigger table: See exofs_init_comps() and comment at
+	 * exofs_read_lookup_dev_table()
+	 */
+	const size_t numores = numdevs * 2 - 1;
+	struct exofs_dev *eds;
+	unsigned i;
+
+	sbi->oc.ods = kzalloc(numores * sizeof(struct ore_dev *) +
+			      numdevs * sizeof(struct exofs_dev), GFP_KERNEL);
+	if (unlikely(!sbi->oc.ods)) {
+		EXOFS_ERR("ERROR: failed allocating Device array[%d]\n",
+			  numdevs);
+		return -ENOMEM;
+	}
+
+	/* Start of allocated struct exofs_dev entries */
+	*peds = eds = (void *)sbi->oc.ods[numores];
+	/* Initialize pointers into struct exofs_dev */
+	for (i = 0; i < numdevs; ++i)
+		sbi->oc.ods[i] = &eds[i].ored;
+	return 0;
+}
+
+static int exofs_read_lookup_dev_table(struct exofs_sb_info *sbi,
+				       struct osd_dev *fscb_od,
+				       unsigned table_count)
+{
+	struct ore_comp comp;
+	struct exofs_device_table *dt;
+	struct exofs_dev *eds;
+	unsigned table_bytes = table_count * sizeof(dt->dt_dev_table[0]) +
+					     sizeof(*dt);
+	unsigned numdevs, i;
+	int ret;
+
+	dt = kmalloc(table_bytes, GFP_KERNEL);
+	if (unlikely(!dt)) {
+		EXOFS_ERR("ERROR: allocating %x bytes for device table\n",
+			  table_bytes);
+		return -ENOMEM;
+	}
+
+	sbi->oc.numdevs = 0;
+
+	comp.obj.partition = sbi->one_comp.obj.partition;
+	comp.obj.id = EXOFS_DEVTABLE_ID;
+	exofs_make_credential(comp.cred, &comp.obj);
+
+	ret = exofs_read_kern(fscb_od, comp.cred, &comp.obj, 0, dt,
+			      table_bytes);
+	if (unlikely(ret)) {
+		EXOFS_ERR("ERROR: reading device table\n");
+		goto out;
+	}
+
+	numdevs = le64_to_cpu(dt->dt_num_devices);
+	if (unlikely(!numdevs)) {
+		ret = -EINVAL;
+		goto out;
+	}
+	WARN_ON(table_count != numdevs);
+
+	ret = _read_and_match_data_map(sbi, numdevs, dt);
+	if (unlikely(ret))
+		goto out;
+
+	ret = __alloc_dev_table(sbi, numdevs, &eds);
+	if (unlikely(ret))
+		goto out;
+	/* exofs round-robins the device table view according to inode
+	 * number. We hold a: twice bigger table hence inodes can point
+	 * to any device and have a sequential view of the table
+	 * starting at this device. See exofs_init_comps()
+	 */
+	memcpy(&sbi->oc.ods[numdevs], &sbi->oc.ods[0],
+		(numdevs - 1) * sizeof(sbi->oc.ods[0]));
+
+	/* create sysfs subdir under which we put the device table
+	 * And cluster layout. A Superblock is identified by the string:
+	 *	"dev[0].osdname"_"pid"
+	 */
+	exofs_sysfs_sb_add(sbi, &dt->dt_dev_table[0]);
+
+	for (i = 0; i < numdevs; i++) {
+		struct exofs_fscb fscb;
+		struct osd_dev_info odi;
+		struct osd_dev *od;
+
+		if (exofs_devs_2_odi(&dt->dt_dev_table[i], &odi)) {
+			EXOFS_ERR("ERROR: Read all-zeros device entry\n");
+			ret = -EINVAL;
+			goto out;
+		}
+
+		printk(KERN_NOTICE "Add device[%d]: osd_name-%s\n",
+		       i, odi.osdname);
+
+		/* the exofs id is currently the table index */
+		eds[i].did = i;
+
+		/* On all devices the device table is identical. The user can
+		 * specify any one of the participating devices on the command
+		 * line. We always keep them in device-table order.
+		 */
+		if (fscb_od && osduld_device_same(fscb_od, &odi)) {
+			eds[i].ored.od = fscb_od;
+			++sbi->oc.numdevs;
+			fscb_od = NULL;
+			exofs_sysfs_odev_add(&eds[i], sbi);
+			continue;
+		}
+
+		od = osduld_info_lookup(&odi);
+		if (IS_ERR(od)) {
+			ret = PTR_ERR(od);
+			EXOFS_ERR("ERROR: device requested is not found "
+				  "osd_name-%s =>%d\n", odi.osdname, ret);
+			goto out;
+		}
+
+		eds[i].ored.od = od;
+		++sbi->oc.numdevs;
+
+		/* Read the fscb of the other devices to make sure the FS
+		 * partition is there.
+		 */
+		ret = exofs_read_kern(od, comp.cred, &comp.obj, 0, &fscb,
+				      sizeof(fscb));
+		if (unlikely(ret)) {
+			EXOFS_ERR("ERROR: Malformed participating device "
+				  "error reading fscb osd_name-%s\n",
+				  odi.osdname);
+			goto out;
+		}
+		exofs_sysfs_odev_add(&eds[i], sbi);
+
+		/* TODO: verify other information is correct and FS-uuid
+		 *	 matches. Benny what did you say about device table
+		 *	 generation and old devices?
+		 */
+	}
+
+out:
+	kfree(dt);
+	if (unlikely(fscb_od && !ret)) {
+			EXOFS_ERR("ERROR: Bad device-table container device not present\n");
+			osduld_put_device(fscb_od);
+			return -EINVAL;
+	}
+	return ret;
+}
+
+/*
+ * Read the superblock from the OSD and fill in the fields
+ */
+static int exofs_fill_super(struct super_block *sb,
+				struct exofs_mountopt *opts,
+				struct exofs_sb_info *sbi,
+				int silent)
+{
+	struct inode *root;
+	struct osd_dev *od;		/* Master device                 */
+	struct exofs_fscb fscb;		/*on-disk superblock info        */
+	struct ore_comp comp;
+	unsigned table_count;
+	int ret;
+
+	/* use mount options to fill superblock */
+	if (opts->is_osdname) {
+		struct osd_dev_info odi = {.systemid_len = 0};
+
+		odi.osdname_len = strlen(opts->dev_name);
+		odi.osdname = (u8 *)opts->dev_name;
+		od = osduld_info_lookup(&odi);
+		kfree(opts->dev_name);
+		opts->dev_name = NULL;
+	} else {
+		od = osduld_path_lookup(opts->dev_name);
+	}
+	if (IS_ERR(od)) {
+		ret = -EINVAL;
+		goto free_sbi;
+	}
+
+	/* Default layout in case we do not have a device-table */
+	sbi->layout.stripe_unit = PAGE_SIZE;
+	sbi->layout.mirrors_p1 = 1;
+	sbi->layout.group_width = 1;
+	sbi->layout.group_depth = -1;
+	sbi->layout.group_count = 1;
+	sbi->s_timeout = opts->timeout;
+
+	sbi->one_comp.obj.partition = opts->pid;
+	sbi->one_comp.obj.id = 0;
+	exofs_make_credential(sbi->one_comp.cred, &sbi->one_comp.obj);
+	sbi->oc.single_comp = EC_SINGLE_COMP;
+	sbi->oc.comps = &sbi->one_comp;
+
+	/* fill in some other data by hand */
+	memset(sb->s_id, 0, sizeof(sb->s_id));
+	strcpy(sb->s_id, "exofs");
+	sb->s_blocksize = EXOFS_BLKSIZE;
+	sb->s_blocksize_bits = EXOFS_BLKSHIFT;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_max_links = EXOFS_LINK_MAX;
+	atomic_set(&sbi->s_curr_pending, 0);
+	sb->s_bdev = NULL;
+	sb->s_dev = 0;
+
+	comp.obj.partition = sbi->one_comp.obj.partition;
+	comp.obj.id = EXOFS_SUPER_ID;
+	exofs_make_credential(comp.cred, &comp.obj);
+
+	ret = exofs_read_kern(od, comp.cred, &comp.obj, 0, &fscb, sizeof(fscb));
+	if (unlikely(ret))
+		goto free_sbi;
+
+	sb->s_magic = le16_to_cpu(fscb.s_magic);
+	/* NOTE: we read below to be backward compatible with old versions */
+	sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
+	sbi->s_numfiles = le32_to_cpu(fscb.s_numfiles);
+
+	/* make sure what we read from the object store is correct */
+	if (sb->s_magic != EXOFS_SUPER_MAGIC) {
+		if (!silent)
+			EXOFS_ERR("ERROR: Bad magic value\n");
+		ret = -EINVAL;
+		goto free_sbi;
+	}
+	if (le32_to_cpu(fscb.s_version) > EXOFS_FSCB_VER) {
+		EXOFS_ERR("ERROR: Bad FSCB version expected-%d got-%d\n",
+			  EXOFS_FSCB_VER, le32_to_cpu(fscb.s_version));
+		ret = -EINVAL;
+		goto free_sbi;
+	}
+
+	/* start generation numbers from a random point */
+	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
+	spin_lock_init(&sbi->s_next_gen_lock);
+
+	table_count = le64_to_cpu(fscb.s_dev_table_count);
+	if (table_count) {
+		ret = exofs_read_lookup_dev_table(sbi, od, table_count);
+		if (unlikely(ret))
+			goto free_sbi;
+	} else {
+		struct exofs_dev *eds;
+
+		ret = __alloc_dev_table(sbi, 1, &eds);
+		if (unlikely(ret))
+			goto free_sbi;
+
+		ore_comp_set_dev(&sbi->oc, 0, od);
+		sbi->oc.numdevs = 1;
+	}
+
+	__sbi_read_stats(sbi);
+
+	/* set up operation vectors */
+	ret = super_setup_bdi(sb);
+	if (ret) {
+		EXOFS_DBGMSG("Failed to super_setup_bdi\n");
+		goto free_sbi;
+	}
+	sb->s_bdi->ra_pages = __ra_pages(&sbi->layout);
+	sb->s_fs_info = sbi;
+	sb->s_op = &exofs_sops;
+	sb->s_export_op = &exofs_export_ops;
+	root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
+	if (IS_ERR(root)) {
+		EXOFS_ERR("ERROR: exofs_iget failed\n");
+		ret = PTR_ERR(root);
+		goto free_sbi;
+	}
+	sb->s_root = d_make_root(root);
+	if (!sb->s_root) {
+		EXOFS_ERR("ERROR: get root inode failed\n");
+		ret = -ENOMEM;
+		goto free_sbi;
+	}
+
+	if (!S_ISDIR(root->i_mode)) {
+		dput(sb->s_root);
+		sb->s_root = NULL;
+		EXOFS_ERR("ERROR: corrupt root inode (mode = %hd)\n",
+		       root->i_mode);
+		ret = -EINVAL;
+		goto free_sbi;
+	}
+
+	exofs_sysfs_dbg_print();
+	_exofs_print_device("Mounting", opts->dev_name,
+			    ore_comp_dev(&sbi->oc, 0),
+			    sbi->one_comp.obj.partition);
+	return 0;
+
+free_sbi:
+	EXOFS_ERR("Unable to mount exofs on %s pid=0x%llx err=%d\n",
+		  opts->dev_name, sbi->one_comp.obj.partition, ret);
+	exofs_free_sbi(sbi);
+	return ret;
+}
+
+/*
+ * Set up the superblock (calls exofs_fill_super eventually)
+ */
+static struct dentry *exofs_mount(struct file_system_type *type,
+			  int flags, const char *dev_name,
+			  void *data)
+{
+	struct super_block *s;
+	struct exofs_mountopt opts;
+	struct exofs_sb_info *sbi;
+	int ret;
+
+	ret = parse_options(data, &opts);
+	if (ret) {
+		kfree(opts.dev_name);
+		return ERR_PTR(ret);
+	}
+
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi) {
+		kfree(opts.dev_name);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	s = sget(type, NULL, set_anon_super, flags, NULL);
+
+	if (IS_ERR(s)) {
+		kfree(opts.dev_name);
+		kfree(sbi);
+		return ERR_CAST(s);
+	}
+
+	if (!opts.dev_name)
+		opts.dev_name = dev_name;
+
+
+	ret = exofs_fill_super(s, &opts, sbi, flags & SB_SILENT ? 1 : 0);
+	if (ret) {
+		deactivate_locked_super(s);
+		return ERR_PTR(ret);
+	}
+	s->s_flags |= SB_ACTIVE;
+	return dget(s->s_root);
+}
+
+/*
+ * Return information about the file system state in the buffer.  This is used
+ * by the 'df' command, for example.
+ */
+static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct ore_io_state *ios;
+	struct osd_attr attrs[] = {
+		ATTR_DEF(OSD_APAGE_PARTITION_QUOTAS,
+			OSD_ATTR_PQ_CAPACITY_QUOTA, sizeof(__be64)),
+		ATTR_DEF(OSD_APAGE_PARTITION_INFORMATION,
+			OSD_ATTR_PI_USED_CAPACITY, sizeof(__be64)),
+	};
+	uint64_t capacity = ULLONG_MAX;
+	uint64_t used = ULLONG_MAX;
+	int ret;
+
+	ret = ore_get_io_state(&sbi->layout, &sbi->oc, &ios);
+	if (ret) {
+		EXOFS_DBGMSG("ore_get_io_state failed.\n");
+		return ret;
+	}
+
+	ios->in_attr = attrs;
+	ios->in_attr_len = ARRAY_SIZE(attrs);
+
+	ret = ore_read(ios);
+	if (unlikely(ret))
+		goto out;
+
+	ret = extract_attr_from_ios(ios, &attrs[0]);
+	if (likely(!ret)) {
+		capacity = get_unaligned_be64(attrs[0].val_ptr);
+		if (unlikely(!capacity))
+			capacity = ULLONG_MAX;
+	} else
+		EXOFS_DBGMSG("exofs_statfs: get capacity failed.\n");
+
+	ret = extract_attr_from_ios(ios, &attrs[1]);
+	if (likely(!ret))
+		used = get_unaligned_be64(attrs[1].val_ptr);
+	else
+		EXOFS_DBGMSG("exofs_statfs: get used-space failed.\n");
+
+	/* fill in the stats buffer */
+	buf->f_type = EXOFS_SUPER_MAGIC;
+	buf->f_bsize = EXOFS_BLKSIZE;
+	buf->f_blocks = capacity >> 9;
+	buf->f_bfree = (capacity - used) >> 9;
+	buf->f_bavail = buf->f_bfree;
+	buf->f_files = sbi->s_numfiles;
+	buf->f_ffree = EXOFS_MAX_ID - sbi->s_numfiles;
+	buf->f_namelen = EXOFS_NAME_LEN;
+
+out:
+	ore_put_io_state(ios);
+	return ret;
+}
+
+static const struct super_operations exofs_sops = {
+	.alloc_inode    = exofs_alloc_inode,
+	.destroy_inode  = exofs_destroy_inode,
+	.write_inode    = exofs_write_inode,
+	.evict_inode    = exofs_evict_inode,
+	.put_super      = exofs_put_super,
+	.sync_fs	= exofs_sync_fs,
+	.statfs         = exofs_statfs,
+};
+
+/******************************************************************************
+ * EXPORT OPERATIONS
+ *****************************************************************************/
+
+static struct dentry *exofs_get_parent(struct dentry *child)
+{
+	unsigned long ino = exofs_parent_ino(child);
+
+	if (!ino)
+		return ERR_PTR(-ESTALE);
+
+	return d_obtain_alias(exofs_iget(child->d_sb, ino));
+}
+
+static struct inode *exofs_nfs_get_inode(struct super_block *sb,
+		u64 ino, u32 generation)
+{
+	struct inode *inode;
+
+	inode = exofs_iget(sb, ino);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	if (generation && inode->i_generation != generation) {
+		/* we didn't find the right inode.. */
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return inode;
+}
+
+static struct dentry *exofs_fh_to_dentry(struct super_block *sb,
+				struct fid *fid, int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    exofs_nfs_get_inode);
+}
+
+static struct dentry *exofs_fh_to_parent(struct super_block *sb,
+				struct fid *fid, int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    exofs_nfs_get_inode);
+}
+
+static const struct export_operations exofs_export_ops = {
+	.fh_to_dentry = exofs_fh_to_dentry,
+	.fh_to_parent = exofs_fh_to_parent,
+	.get_parent = exofs_get_parent,
+};
+
+/******************************************************************************
+ * INSMOD/RMMOD
+ *****************************************************************************/
+
+/*
+ * struct that describes this file system
+ */
+static struct file_system_type exofs_type = {
+	.owner          = THIS_MODULE,
+	.name           = "exofs",
+	.mount          = exofs_mount,
+	.kill_sb        = generic_shutdown_super,
+};
+MODULE_ALIAS_FS("exofs");
+
+static int __init init_exofs(void)
+{
+	int err;
+
+	err = init_inodecache();
+	if (err)
+		goto out;
+
+	err = register_filesystem(&exofs_type);
+	if (err)
+		goto out_d;
+
+	/* We don't fail if sysfs creation failed */
+	exofs_sysfs_init();
+
+	return 0;
+out_d:
+	destroy_inodecache();
+out:
+	return err;
+}
+
+static void __exit exit_exofs(void)
+{
+	exofs_sysfs_uninit();
+	unregister_filesystem(&exofs_type);
+	destroy_inodecache();
+}
+
+MODULE_AUTHOR("Avishay Traeger <avishay@gmail.com>");
+MODULE_DESCRIPTION("exofs");
+MODULE_LICENSE("GPL");
+
+module_init(init_exofs)
+module_exit(exit_exofs)
diff --git a/src/kernel/linux/v4.19/fs/exofs/sys.c b/src/kernel/linux/v4.19/fs/exofs/sys.c
new file mode 100644
index 0000000..1f7d5e4
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/exofs/sys.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (C) 2012
+ * Sachin Bhamare <sbhamare@panasas.com>
+ * Boaz Harrosh <ooo@electrozaur.com>
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 2 as published by
+ * the Free Software Foundation.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the:
+ *	Free Software Foundation <licensing@fsf.org>
+ */
+
+#include <linux/kobject.h>
+#include <linux/device.h>
+
+#include "exofs.h"
+
+struct odev_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct exofs_dev *, char *);
+	ssize_t (*store)(struct exofs_dev *, const char *, size_t);
+};
+
+static ssize_t odev_attr_show(struct kobject *kobj, struct attribute *attr,
+		char *buf)
+{
+	struct exofs_dev *edp = container_of(kobj, struct exofs_dev, ed_kobj);
+	struct odev_attr *a = container_of(attr, struct odev_attr, attr);
+
+	return a->show ? a->show(edp, buf) : 0;
+}
+
+static ssize_t odev_attr_store(struct kobject *kobj, struct attribute *attr,
+		const char *buf, size_t len)
+{
+	struct exofs_dev *edp = container_of(kobj, struct exofs_dev, ed_kobj);
+	struct odev_attr *a = container_of(attr, struct odev_attr, attr);
+
+	return a->store ? a->store(edp, buf, len) : len;
+}
+
+static const struct sysfs_ops odev_attr_ops = {
+	.show  = odev_attr_show,
+	.store = odev_attr_store,
+};
+
+
+static struct kset *exofs_kset;
+
+static ssize_t osdname_show(struct exofs_dev *edp, char *buf)
+{
+	struct osd_dev *odev = edp->ored.od;
+	const struct osd_dev_info *odi = osduld_device_info(odev);
+
+	return snprintf(buf, odi->osdname_len + 1, "%s", odi->osdname);
+}
+
+static ssize_t systemid_show(struct exofs_dev *edp, char *buf)
+{
+	struct osd_dev *odev = edp->ored.od;
+	const struct osd_dev_info *odi = osduld_device_info(odev);
+
+	memcpy(buf, odi->systemid, odi->systemid_len);
+	return odi->systemid_len;
+}
+
+static ssize_t uri_show(struct exofs_dev *edp, char *buf)
+{
+	return snprintf(buf, edp->urilen, "%s", edp->uri);
+}
+
+static ssize_t uri_store(struct exofs_dev *edp, const char *buf, size_t len)
+{
+	uint8_t *new_uri;
+
+	edp->urilen = strlen(buf) + 1;
+	new_uri = krealloc(edp->uri, edp->urilen, GFP_KERNEL);
+	if (new_uri == NULL)
+		return -ENOMEM;
+	edp->uri = new_uri;
+	strncpy(edp->uri, buf, edp->urilen);
+	return edp->urilen;
+}
+
+#define OSD_ATTR(name, mode, show, store) \
+	static struct odev_attr odev_attr_##name = \
+					__ATTR(name, mode, show, store)
+
+OSD_ATTR(osdname, S_IRUGO, osdname_show, NULL);
+OSD_ATTR(systemid, S_IRUGO, systemid_show, NULL);
+OSD_ATTR(uri, S_IRWXU, uri_show, uri_store);
+
+static struct attribute *odev_attrs[] = {
+	&odev_attr_osdname.attr,
+	&odev_attr_systemid.attr,
+	&odev_attr_uri.attr,
+	NULL,
+};
+
+static struct kobj_type odev_ktype = {
+	.default_attrs	= odev_attrs,
+	.sysfs_ops	= &odev_attr_ops,
+};
+
+static struct kobj_type uuid_ktype = {
+};
+
+void exofs_sysfs_dbg_print(void)
+{
+#ifdef CONFIG_EXOFS_DEBUG
+	struct kobject *k_name, *k_tmp;
+
+	list_for_each_entry_safe(k_name, k_tmp, &exofs_kset->list, entry) {
+		printk(KERN_INFO "%s: name %s ref %d\n",
+			__func__, kobject_name(k_name),
+			(int)kref_read(&k_name->kref));
+	}
+#endif
+}
+/*
+ * This function removes all kobjects under exofs_kset
+ * At the end of it, exofs_kset kobject will have a refcount
+ * of 1 which gets decremented only on exofs module unload
+ */
+void exofs_sysfs_sb_del(struct exofs_sb_info *sbi)
+{
+	struct kobject *k_name, *k_tmp;
+	struct kobject *s_kobj = &sbi->s_kobj;
+
+	list_for_each_entry_safe(k_name, k_tmp, &exofs_kset->list, entry) {
+		/* Remove all that are children of this SBI */
+		if (k_name->parent == s_kobj)
+			kobject_put(k_name);
+	}
+	kobject_put(s_kobj);
+}
+
+/*
+ * This function creates sysfs entries to hold the current exofs cluster
+ * instance (uniquely identified by osdname,pid tuple).
+ * This function gets called once per exofs mount instance.
+ */
+int exofs_sysfs_sb_add(struct exofs_sb_info *sbi,
+		       struct exofs_dt_device_info *dt_dev)
+{
+	struct kobject *s_kobj;
+	int retval = 0;
+	uint64_t pid = sbi->one_comp.obj.partition;
+
+	/* allocate new uuid dirent */
+	s_kobj = &sbi->s_kobj;
+	s_kobj->kset = exofs_kset;
+	retval = kobject_init_and_add(s_kobj, &uuid_ktype,
+			&exofs_kset->kobj,  "%s_%llx", dt_dev->osdname, pid);
+	if (retval) {
+		EXOFS_ERR("ERROR: Failed to create sysfs entry for "
+			  "uuid-%s_%llx => %d\n", dt_dev->osdname, pid, retval);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+int exofs_sysfs_odev_add(struct exofs_dev *edev, struct exofs_sb_info *sbi)
+{
+	struct kobject *d_kobj;
+	int retval = 0;
+
+	/* create osd device group which contains following attributes
+	 * osdname, systemid & uri
+	 */
+	d_kobj = &edev->ed_kobj;
+	d_kobj->kset = exofs_kset;
+	retval = kobject_init_and_add(d_kobj, &odev_ktype,
+			&sbi->s_kobj, "dev%u", edev->did);
+	if (retval) {
+		EXOFS_ERR("ERROR: Failed to create sysfs entry for "
+				"device dev%u\n", edev->did);
+		return retval;
+	}
+	return 0;
+}
+
+int exofs_sysfs_init(void)
+{
+	exofs_kset = kset_create_and_add("exofs", NULL, fs_kobj);
+	if (!exofs_kset) {
+		EXOFS_ERR("ERROR: kset_create_and_add exofs failed\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void exofs_sysfs_uninit(void)
+{
+	kset_unregister(exofs_kset);
+}