staging: add Lustre file system client support

Lustre is the most deployed distributed file system
in the HPC (High Performance Computing) world. The patch
adds its client side support.

The code is not very clean and needs to live in drivers/staging
for some time for continuing cleanup work. See
drivers/staging/lustre/TODO for details.

The code is based on Lustre master commit faefbfc04

commit faefbfc0460bc00f2ee4c1c1c86aa1e39b9eea49
Author: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Date:   Tue Apr 30 23:05:21 2013 +0400

    LU-3244 utils: tunefs.lustre should preserve virgin label

Plus a few under-review patches on Whamcloud gerrit:
3.8 kernel support:
http://review.whamcloud.com/#change,5973
http://review.whamcloud.com/#change,5974
http://review.whamcloud.com/#change,5768
http://review.whamcloud.com/#change,5781
http://review.whamcloud.com/#change,5763
http://review.whamcloud.com/#change,5613
http://review.whamcloud.com/#change,5655

3.9 kernel support:
http://review.whamcloud.com/#change,5898
http://review.whamcloud.com/#change,5899

Kconfig/Kbuild:
http://review.whamcloud.com/#change,4646
http://review.whamcloud.com/#change,4644

libcfs cleanup:
http://review.whamcloud.com/#change,2831
http://review.whamcloud.com/#change,4775
http://review.whamcloud.com/#change,4776
http://review.whamcloud.com/#change,4777
http://review.whamcloud.com/#change,4778
http://review.whamcloud.com/#change,4779
http://review.whamcloud.com/#change,4780

All starting/trailing whitespaces are removed, to match kernel
coding style. Also ran scripts/cleanfile on all lustre source files.

[maked the Kconfig depend on BROKEN as the recent procfs changes causes
this to fail - gregkh]

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1175 insertions, 0 deletions

diff --git a/drivers/staging/lustre/lustre/llite/vvp_io.c b/drivers/staging/lustre/lustre/llite/vvp_io.c
new file mode 100644
index 000000000000..8504d448aac8
--- /dev/null
+++ b/drivers/staging/lustre/lustre/llite/vvp_io.c
@@ -0,0 +1,1175 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program 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 version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ *
+ * Implementation of cl_io for VVP layer.
+ *
+ *   Author: Nikita Danilov <nikita.danilov@sun.com>
+ *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
+ */
+
+#define DEBUG_SUBSYSTEM S_LLITE
+
+
+#include <obd.h>
+#include <lustre_lite.h>
+
+#include "vvp_internal.h"
+
+static struct vvp_io *cl2vvp_io(const struct lu_env *env,
+				const struct cl_io_slice *slice);
+
+/**
+ * True, if \a io is a normal io, False for sendfile() / splice_{read|write}
+ */
+int cl_is_normalio(const struct lu_env *env, const struct cl_io *io)
+{
+	struct vvp_io *vio = vvp_env_io(env);
+
+	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
+
+	return vio->cui_io_subtype == IO_NORMAL;
+}
+
+/**
+ * For swapping layout. The file's layout may have changed.
+ * To avoid populating pages to a wrong stripe, we have to verify the
+ * correctness of layout. It works because swapping layout processes
+ * have to acquire group lock.
+ */
+static bool can_populate_pages(const struct lu_env *env, struct cl_io *io,
+				struct inode *inode)
+{
+	struct ll_inode_info	*lli = ll_i2info(inode);
+	struct ccc_io		*cio = ccc_env_io(env);
+	bool rc = true;
+
+	switch (io->ci_type) {
+	case CIT_READ:
+	case CIT_WRITE:
+		/* don't need lock here to check lli_layout_gen as we have held
+		 * extent lock and GROUP lock has to hold to swap layout */
+		if (lli->lli_layout_gen != cio->cui_layout_gen) {
+			io->ci_need_restart = 1;
+			/* this will return application a short read/write */
+			io->ci_continue = 0;
+			rc = false;
+		}
+	case CIT_FAULT:
+		/* fault is okay because we've already had a page. */
+	default:
+		break;
+	}
+
+	return rc;
+}
+
+/*****************************************************************************
+ *
+ * io operations.
+ *
+ */
+
+static int vvp_io_fault_iter_init(const struct lu_env *env,
+				  const struct cl_io_slice *ios)
+{
+	struct vvp_io *vio   = cl2vvp_io(env, ios);
+	struct inode  *inode = ccc_object_inode(ios->cis_obj);
+
+	LASSERT(inode ==
+		cl2ccc_io(env, ios)->cui_fd->fd_file->f_dentry->d_inode);
+	vio->u.fault.ft_mtime = LTIME_S(inode->i_mtime);
+	return 0;
+}
+
+static void vvp_io_fini(const struct lu_env *env, const struct cl_io_slice *ios)
+{
+	struct cl_io     *io  = ios->cis_io;
+	struct cl_object *obj = io->ci_obj;
+	struct ccc_io    *cio = cl2ccc_io(env, ios);
+
+	CLOBINVRNT(env, obj, ccc_object_invariant(obj));
+
+	CDEBUG(D_VFSTRACE, "ignore/verify layout %d/%d, layout version %d.\n",
+		io->ci_ignore_layout, io->ci_verify_layout, cio->cui_layout_gen);
+
+	if (!io->ci_ignore_layout && io->ci_verify_layout) {
+		__u32 gen = 0;
+
+		/* check layout version */
+		ll_layout_refresh(ccc_object_inode(obj), &gen);
+		io->ci_need_restart = cio->cui_layout_gen != gen;
+		if (io->ci_need_restart)
+			CDEBUG(D_VFSTRACE, "layout changed from %d to %d.\n",
+				cio->cui_layout_gen, gen);
+	}
+}
+
+static void vvp_io_fault_fini(const struct lu_env *env,
+			      const struct cl_io_slice *ios)
+{
+	struct cl_io   *io   = ios->cis_io;
+	struct cl_page *page = io->u.ci_fault.ft_page;
+
+	CLOBINVRNT(env, io->ci_obj, ccc_object_invariant(io->ci_obj));
+
+	if (page != NULL) {
+		lu_ref_del(&page->cp_reference, "fault", io);
+		cl_page_put(env, page);
+		io->u.ci_fault.ft_page = NULL;
+	}
+	vvp_io_fini(env, ios);
+}
+
+enum cl_lock_mode vvp_mode_from_vma(struct vm_area_struct *vma)
+{
+	/*
+	 * we only want to hold PW locks if the mmap() can generate
+	 * writes back to the file and that only happens in shared
+	 * writable vmas
+	 */
+	if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
+		return CLM_WRITE;
+	return CLM_READ;
+}
+
+static int vvp_mmap_locks(const struct lu_env *env,
+			  struct ccc_io *vio, struct cl_io *io)
+{
+	struct ccc_thread_info *cti = ccc_env_info(env);
+	struct mm_struct       *mm = current->mm;
+	struct vm_area_struct  *vma;
+	struct cl_lock_descr   *descr = &cti->cti_descr;
+	ldlm_policy_data_t      policy;
+	unsigned long	   addr;
+	unsigned long	   seg;
+	ssize_t		 count;
+	int		     result;
+	ENTRY;
+
+	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
+
+	if (!cl_is_normalio(env, io))
+		RETURN(0);
+
+	if (vio->cui_iov == NULL) /* nfs or loop back device write */
+		RETURN(0);
+
+	/* No MM (e.g. NFS)? No vmas too. */
+	if (mm == NULL)
+		RETURN(0);
+
+	for (seg = 0; seg < vio->cui_nrsegs; seg++) {
+		const struct iovec *iv = &vio->cui_iov[seg];
+
+		addr = (unsigned long)iv->iov_base;
+		count = iv->iov_len;
+		if (count == 0)
+			continue;
+
+		count += addr & (~CFS_PAGE_MASK);
+		addr &= CFS_PAGE_MASK;
+
+		down_read(&mm->mmap_sem);
+		while((vma = our_vma(mm, addr, count)) != NULL) {
+			struct inode *inode = vma->vm_file->f_dentry->d_inode;
+			int flags = CEF_MUST;
+
+			if (ll_file_nolock(vma->vm_file)) {
+				/*
+				 * For no lock case, a lockless lock will be
+				 * generated.
+				 */
+				flags = CEF_NEVER;
+			}
+
+			/*
+			 * XXX: Required lock mode can be weakened: CIT_WRITE
+			 * io only ever reads user level buffer, and CIT_READ
+			 * only writes on it.
+			 */
+			policy_from_vma(&policy, vma, addr, count);
+			descr->cld_mode = vvp_mode_from_vma(vma);
+			descr->cld_obj = ll_i2info(inode)->lli_clob;
+			descr->cld_start = cl_index(descr->cld_obj,
+						    policy.l_extent.start);
+			descr->cld_end = cl_index(descr->cld_obj,
+						  policy.l_extent.end);
+			descr->cld_enq_flags = flags;
+			result = cl_io_lock_alloc_add(env, io, descr);
+
+			CDEBUG(D_VFSTRACE, "lock: %d: [%lu, %lu]\n",
+			       descr->cld_mode, descr->cld_start,
+			       descr->cld_end);
+
+			if (result < 0)
+				RETURN(result);
+
+			if (vma->vm_end - addr >= count)
+				break;
+
+			count -= vma->vm_end - addr;
+			addr = vma->vm_end;
+		}
+		up_read(&mm->mmap_sem);
+	}
+	RETURN(0);
+}
+
+static int vvp_io_rw_lock(const struct lu_env *env, struct cl_io *io,
+			  enum cl_lock_mode mode, loff_t start, loff_t end)
+{
+	struct ccc_io *cio = ccc_env_io(env);
+	int result;
+	int ast_flags = 0;
+
+	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
+	ENTRY;
+
+	ccc_io_update_iov(env, cio, io);
+
+	if (io->u.ci_rw.crw_nonblock)
+		ast_flags |= CEF_NONBLOCK;
+	result = vvp_mmap_locks(env, cio, io);
+	if (result == 0)
+		result = ccc_io_one_lock(env, io, ast_flags, mode, start, end);
+	RETURN(result);
+}
+
+static int vvp_io_read_lock(const struct lu_env *env,
+			    const struct cl_io_slice *ios)
+{
+	struct cl_io	 *io  = ios->cis_io;
+	struct ll_inode_info *lli = ll_i2info(ccc_object_inode(io->ci_obj));
+	int result;
+
+	ENTRY;
+	/* XXX: Layer violation, we shouldn't see lsm at llite level. */
+	if (lli->lli_has_smd) /* lsm-less file doesn't need to lock */
+		result = vvp_io_rw_lock(env, io, CLM_READ,
+					io->u.ci_rd.rd.crw_pos,
+					io->u.ci_rd.rd.crw_pos +
+					io->u.ci_rd.rd.crw_count - 1);
+	else
+		result = 0;
+	RETURN(result);
+}
+
+static int vvp_io_fault_lock(const struct lu_env *env,
+			     const struct cl_io_slice *ios)
+{
+	struct cl_io *io   = ios->cis_io;
+	struct vvp_io *vio = cl2vvp_io(env, ios);
+	/*
+	 * XXX LDLM_FL_CBPENDING
+	 */
+	return ccc_io_one_lock_index
+		(env, io, 0, vvp_mode_from_vma(vio->u.fault.ft_vma),
+		 io->u.ci_fault.ft_index, io->u.ci_fault.ft_index);
+}
+
+static int vvp_io_write_lock(const struct lu_env *env,
+			     const struct cl_io_slice *ios)
+{
+	struct cl_io *io = ios->cis_io;
+	loff_t start;
+	loff_t end;
+
+	if (io->u.ci_wr.wr_append) {
+		start = 0;
+		end   = OBD_OBJECT_EOF;
+	} else {
+		start = io->u.ci_wr.wr.crw_pos;
+		end   = start + io->u.ci_wr.wr.crw_count - 1;
+	}
+	return vvp_io_rw_lock(env, io, CLM_WRITE, start, end);
+}
+
+static int vvp_io_setattr_iter_init(const struct lu_env *env,
+				    const struct cl_io_slice *ios)
+{
+	return 0;
+}
+
+/**
+ * Implementation of cl_io_operations::cio_lock() method for CIT_SETATTR io.
+ *
+ * Handles "lockless io" mode when extent locking is done by server.
+ */
+static int vvp_io_setattr_lock(const struct lu_env *env,
+			       const struct cl_io_slice *ios)
+{
+	struct ccc_io *cio = ccc_env_io(env);
+	struct cl_io  *io  = ios->cis_io;
+	__u64 new_size;
+	__u32 enqflags = 0;
+
+	if (cl_io_is_trunc(io)) {
+		new_size = io->u.ci_setattr.sa_attr.lvb_size;
+		if (new_size == 0)
+			enqflags = CEF_DISCARD_DATA;
+	} else {
+		if ((io->u.ci_setattr.sa_attr.lvb_mtime >=
+		     io->u.ci_setattr.sa_attr.lvb_ctime) ||
+		    (io->u.ci_setattr.sa_attr.lvb_atime >=
+		     io->u.ci_setattr.sa_attr.lvb_ctime))
+			return 0;
+		new_size = 0;
+	}
+	cio->u.setattr.cui_local_lock = SETATTR_EXTENT_LOCK;
+	return ccc_io_one_lock(env, io, enqflags, CLM_WRITE,
+			       new_size, OBD_OBJECT_EOF);
+}
+
+static int vvp_do_vmtruncate(struct inode *inode, size_t size)
+{
+	int     result;
+	/*
+	 * Only ll_inode_size_lock is taken at this level.
+	 */
+	ll_inode_size_lock(inode);
+	result = inode_newsize_ok(inode, size);
+	if (result < 0) {
+		ll_inode_size_unlock(inode);
+		return result;
+	}
+	truncate_setsize(inode, size);
+	ll_inode_size_unlock(inode);
+	return result;
+}
+
+static int vvp_io_setattr_trunc(const struct lu_env *env,
+				const struct cl_io_slice *ios,
+				struct inode *inode, loff_t size)
+{
+	inode_dio_wait(inode);
+	return 0;
+}
+
+static int vvp_io_setattr_time(const struct lu_env *env,
+			       const struct cl_io_slice *ios)
+{
+	struct cl_io       *io    = ios->cis_io;
+	struct cl_object   *obj   = io->ci_obj;
+	struct cl_attr     *attr  = ccc_env_thread_attr(env);
+	int result;
+	unsigned valid = CAT_CTIME;
+
+	cl_object_attr_lock(obj);
+	attr->cat_ctime = io->u.ci_setattr.sa_attr.lvb_ctime;
+	if (io->u.ci_setattr.sa_valid & ATTR_ATIME_SET) {
+		attr->cat_atime = io->u.ci_setattr.sa_attr.lvb_atime;
+		valid |= CAT_ATIME;
+	}
+	if (io->u.ci_setattr.sa_valid & ATTR_MTIME_SET) {
+		attr->cat_mtime = io->u.ci_setattr.sa_attr.lvb_mtime;
+		valid |= CAT_MTIME;
+	}
+	result = cl_object_attr_set(env, obj, attr, valid);
+	cl_object_attr_unlock(obj);
+
+	return result;
+}
+
+static int vvp_io_setattr_start(const struct lu_env *env,
+				const struct cl_io_slice *ios)
+{
+	struct cl_io	*io    = ios->cis_io;
+	struct inode	*inode = ccc_object_inode(io->ci_obj);
+
+	mutex_lock(&inode->i_mutex);
+	if (cl_io_is_trunc(io))
+		return vvp_io_setattr_trunc(env, ios, inode,
+					    io->u.ci_setattr.sa_attr.lvb_size);
+	else
+		return vvp_io_setattr_time(env, ios);
+}
+
+static void vvp_io_setattr_end(const struct lu_env *env,
+			       const struct cl_io_slice *ios)
+{
+	struct cl_io *io    = ios->cis_io;
+	struct inode *inode = ccc_object_inode(io->ci_obj);
+
+	if (cl_io_is_trunc(io)) {
+		/* Truncate in memory pages - they must be clean pages
+		 * because osc has already notified to destroy osc_extents. */
+		vvp_do_vmtruncate(inode, io->u.ci_setattr.sa_attr.lvb_size);
+		inode_dio_write_done(inode);
+	}
+	mutex_unlock(&inode->i_mutex);
+}
+
+static void vvp_io_setattr_fini(const struct lu_env *env,
+				const struct cl_io_slice *ios)
+{
+	vvp_io_fini(env, ios);
+}
+
+static ssize_t lustre_generic_file_read(struct file *file,
+					struct ccc_io *vio, loff_t *ppos)
+{
+	return generic_file_aio_read(vio->cui_iocb, vio->cui_iov,
+				     vio->cui_nrsegs, *ppos);
+}
+
+static ssize_t lustre_generic_file_write(struct file *file,
+					struct ccc_io *vio, loff_t *ppos)
+{
+	return generic_file_aio_write(vio->cui_iocb, vio->cui_iov,
+				      vio->cui_nrsegs, *ppos);
+}
+
+static int vvp_io_read_start(const struct lu_env *env,
+			     const struct cl_io_slice *ios)
+{
+	struct vvp_io     *vio   = cl2vvp_io(env, ios);
+	struct ccc_io     *cio   = cl2ccc_io(env, ios);
+	struct cl_io      *io    = ios->cis_io;
+	struct cl_object  *obj   = io->ci_obj;
+	struct inode      *inode = ccc_object_inode(obj);
+	struct ll_ra_read *bead  = &vio->cui_bead;
+	struct file       *file  = cio->cui_fd->fd_file;
+
+	int     result;
+	loff_t  pos = io->u.ci_rd.rd.crw_pos;
+	long    cnt = io->u.ci_rd.rd.crw_count;
+	long    tot = cio->cui_tot_count;
+	int     exceed = 0;
+
+	CLOBINVRNT(env, obj, ccc_object_invariant(obj));
+
+	CDEBUG(D_VFSTRACE, "read: -> [%lli, %lli)\n", pos, pos + cnt);
+
+	if (!can_populate_pages(env, io, inode))
+		return 0;
+
+	result = ccc_prep_size(env, obj, io, pos, tot, &exceed);
+	if (result != 0)
+		return result;
+	else if (exceed != 0)
+		goto out;
+
+	LU_OBJECT_HEADER(D_INODE, env, &obj->co_lu,
+			"Read ino %lu, %lu bytes, offset %lld, size %llu\n",
+			inode->i_ino, cnt, pos, i_size_read(inode));
+
+	/* turn off the kernel's read-ahead */
+	cio->cui_fd->fd_file->f_ra.ra_pages = 0;
+
+	/* initialize read-ahead window once per syscall */
+	if (!vio->cui_ra_window_set) {
+		vio->cui_ra_window_set = 1;
+		bead->lrr_start = cl_index(obj, pos);
+		/*
+		 * XXX: explicit PAGE_CACHE_SIZE
+		 */
+		bead->lrr_count = cl_index(obj, tot + PAGE_CACHE_SIZE - 1);
+		ll_ra_read_in(file, bead);
+	}
+
+	/* BUG: 5972 */
+	file_accessed(file);
+	switch (vio->cui_io_subtype) {
+	case IO_NORMAL:
+		 result = lustre_generic_file_read(file, cio, &pos);
+		 break;
+	case IO_SPLICE:
+		result = generic_file_splice_read(file, &pos,
+				vio->u.splice.cui_pipe, cnt,
+				vio->u.splice.cui_flags);
+		/* LU-1109: do splice read stripe by stripe otherwise if it
+		 * may make nfsd stuck if this read occupied all internal pipe
+		 * buffers. */
+		io->ci_continue = 0;
+		break;
+	default:
+		CERROR("Wrong IO type %u\n", vio->cui_io_subtype);
+		LBUG();
+	}
+
+out:
+	if (result >= 0) {
+		if (result < cnt)
+			io->ci_continue = 0;
+		io->ci_nob += result;
+		ll_rw_stats_tally(ll_i2sbi(inode), current->pid,
+				  cio->cui_fd, pos, result, 0);
+		result = 0;
+	}
+	return result;
+}
+
+static void vvp_io_read_fini(const struct lu_env *env, const struct cl_io_slice *ios)
+{
+	struct vvp_io *vio = cl2vvp_io(env, ios);
+	struct ccc_io *cio = cl2ccc_io(env, ios);
+
+	if (vio->cui_ra_window_set)
+		ll_ra_read_ex(cio->cui_fd->fd_file, &vio->cui_bead);
+
+	vvp_io_fini(env, ios);
+}
+
+static int vvp_io_write_start(const struct lu_env *env,
+			      const struct cl_io_slice *ios)
+{
+	struct ccc_io      *cio   = cl2ccc_io(env, ios);
+	struct cl_io       *io    = ios->cis_io;
+	struct cl_object   *obj   = io->ci_obj;
+	struct inode       *inode = ccc_object_inode(obj);
+	struct file	*file  = cio->cui_fd->fd_file;
+	ssize_t result = 0;
+	loff_t pos = io->u.ci_wr.wr.crw_pos;
+	size_t cnt = io->u.ci_wr.wr.crw_count;
+
+	ENTRY;
+
+	if (!can_populate_pages(env, io, inode))
+		return 0;
+
+	if (cl_io_is_append(io)) {
+		/*
+		 * PARALLEL IO This has to be changed for parallel IO doing
+		 * out-of-order writes.
+		 */
+		pos = io->u.ci_wr.wr.crw_pos = i_size_read(inode);
+		cio->cui_iocb->ki_pos = pos;
+	}
+
+	CDEBUG(D_VFSTRACE, "write: [%lli, %lli)\n", pos, pos + (long long)cnt);
+
+	if (cio->cui_iov == NULL) /* from a temp io in ll_cl_init(). */
+		result = 0;
+	else
+		result = lustre_generic_file_write(file, cio, &pos);
+
+	if (result > 0) {
+		if (result < cnt)
+			io->ci_continue = 0;
+		io->ci_nob += result;
+		ll_rw_stats_tally(ll_i2sbi(inode), current->pid,
+				  cio->cui_fd, pos, result, 0);
+		result = 0;
+	}
+	RETURN(result);
+}
+
+static int vvp_io_kernel_fault(struct vvp_fault_io *cfio)
+{
+	struct vm_fault *vmf = cfio->fault.ft_vmf;
+
+	cfio->fault.ft_flags = filemap_fault(cfio->ft_vma, vmf);
+
+	if (vmf->page) {
+		LL_CDEBUG_PAGE(D_PAGE, vmf->page, "got addr %p type NOPAGE\n",
+			       vmf->virtual_address);
+		if (unlikely(!(cfio->fault.ft_flags & VM_FAULT_LOCKED))) {
+			lock_page(vmf->page);
+			cfio->fault.ft_flags &= VM_FAULT_LOCKED;
+		}
+
+		cfio->ft_vmpage = vmf->page;
+		return 0;
+	}
+
+	if (cfio->fault.ft_flags & VM_FAULT_SIGBUS) {
+		CDEBUG(D_PAGE, "got addr %p - SIGBUS\n", vmf->virtual_address);
+		return -EFAULT;
+	}
+
+	if (cfio->fault.ft_flags & VM_FAULT_OOM) {
+		CDEBUG(D_PAGE, "got addr %p - OOM\n", vmf->virtual_address);
+		return -ENOMEM;
+	}
+
+	if (cfio->fault.ft_flags & VM_FAULT_RETRY)
+		return -EAGAIN;
+
+	CERROR("unknow error in page fault %d!\n", cfio->fault.ft_flags);
+	return -EINVAL;
+}
+
+
+static int vvp_io_fault_start(const struct lu_env *env,
+			      const struct cl_io_slice *ios)
+{
+	struct vvp_io       *vio     = cl2vvp_io(env, ios);
+	struct cl_io	*io      = ios->cis_io;
+	struct cl_object    *obj     = io->ci_obj;
+	struct inode	*inode   = ccc_object_inode(obj);
+	struct cl_fault_io  *fio     = &io->u.ci_fault;
+	struct vvp_fault_io *cfio    = &vio->u.fault;
+	loff_t	       offset;
+	int		  result  = 0;
+	struct page	  *vmpage  = NULL;
+	struct cl_page      *page;
+	loff_t	       size;
+	pgoff_t	      last; /* last page in a file data region */
+
+	if (fio->ft_executable &&
+	    LTIME_S(inode->i_mtime) != vio->u.fault.ft_mtime)
+		CWARN("binary "DFID
+		      " changed while waiting for the page fault lock\n",
+		      PFID(lu_object_fid(&obj->co_lu)));
+
+	/* offset of the last byte on the page */
+	offset = cl_offset(obj, fio->ft_index + 1) - 1;
+	LASSERT(cl_index(obj, offset) == fio->ft_index);
+	result = ccc_prep_size(env, obj, io, 0, offset + 1, NULL);
+	if (result != 0)
+		return result;
+
+	/* must return locked page */
+	if (fio->ft_mkwrite) {
+		LASSERT(cfio->ft_vmpage != NULL);
+		lock_page(cfio->ft_vmpage);
+	} else {
+		result = vvp_io_kernel_fault(cfio);
+		if (result != 0)
+			return result;
+	}
+
+	vmpage = cfio->ft_vmpage;
+	LASSERT(PageLocked(vmpage));
+
+	if (OBD_FAIL_CHECK(OBD_FAIL_LLITE_FAULT_TRUNC_RACE))
+		ll_invalidate_page(vmpage);
+
+	size = i_size_read(inode);
+	/* Though we have already held a cl_lock upon this page, but
+	 * it still can be truncated locally. */
+	if (unlikely((vmpage->mapping != inode->i_mapping) ||
+		     (page_offset(vmpage) > size))) {
+		CDEBUG(D_PAGE, "llite: fault and truncate race happened!\n");
+
+		/* return +1 to stop cl_io_loop() and ll_fault() will catch
+		 * and retry. */
+		GOTO(out, result = +1);
+	}
+
+
+	if (fio->ft_mkwrite ) {
+		pgoff_t last_index;
+		/*
+		 * Capture the size while holding the lli_trunc_sem from above
+		 * we want to make sure that we complete the mkwrite action
+		 * while holding this lock. We need to make sure that we are
+		 * not past the end of the file.
+		 */
+		last_index = cl_index(obj, size - 1);
+		if (last_index < fio->ft_index) {
+			CDEBUG(D_PAGE,
+				"llite: mkwrite and truncate race happened: "
+				"%p: 0x%lx 0x%lx\n",
+				vmpage->mapping,fio->ft_index,last_index);
+			/*
+			 * We need to return if we are
+			 * passed the end of the file. This will propagate
+			 * up the call stack to ll_page_mkwrite where
+			 * we will return VM_FAULT_NOPAGE. Any non-negative
+			 * value returned here will be silently
+			 * converted to 0. If the vmpage->mapping is null
+			 * the error code would be converted back to ENODATA
+			 * in ll_page_mkwrite0. Thus we return -ENODATA
+			 * to handle both cases
+			 */
+			GOTO(out, result = -ENODATA);
+		}
+	}
+
+	page = cl_page_find(env, obj, fio->ft_index, vmpage, CPT_CACHEABLE);
+	if (IS_ERR(page))
+		GOTO(out, result = PTR_ERR(page));
+
+	/* if page is going to be written, we should add this page into cache
+	 * earlier. */
+	if (fio->ft_mkwrite) {
+		wait_on_page_writeback(vmpage);
+		if (set_page_dirty(vmpage)) {
+			struct ccc_page *cp;
+
+			/* vvp_page_assume() calls wait_on_page_writeback(). */
+			cl_page_assume(env, io, page);
+
+			cp = cl2ccc_page(cl_page_at(page, &vvp_device_type));
+			vvp_write_pending(cl2ccc(obj), cp);
+
+			/* Do not set Dirty bit here so that in case IO is
+			 * started before the page is really made dirty, we
+			 * still have chance to detect it. */
+			result = cl_page_cache_add(env, io, page, CRT_WRITE);
+			LASSERT(cl_page_is_owned(page, io));
+
+			vmpage = NULL;
+			if (result < 0) {
+				cl_page_unmap(env, io, page);
+				cl_page_discard(env, io, page);
+				cl_page_disown(env, io, page);
+
+				cl_page_put(env, page);
+
+				/* we're in big trouble, what can we do now? */
+				if (result == -EDQUOT)
+					result = -ENOSPC;
+				GOTO(out, result);
+			} else
+				cl_page_disown(env, io, page);
+		}
+	}
+
+	last = cl_index(obj, size - 1);
+	/*
+	 * The ft_index is only used in the case of
+	 * a mkwrite action. We need to check
+	 * our assertions are correct, since
+	 * we should have caught this above
+	 */
+	LASSERT(!fio->ft_mkwrite || fio->ft_index <= last);
+	if (fio->ft_index == last)
+		/*
+		 * Last page is mapped partially.
+		 */
+		fio->ft_nob = size - cl_offset(obj, fio->ft_index);
+	else
+		fio->ft_nob = cl_page_size(obj);
+
+	lu_ref_add(&page->cp_reference, "fault", io);
+	fio->ft_page = page;
+	EXIT;
+
+out:
+	/* return unlocked vmpage to avoid deadlocking */
+	if (vmpage != NULL)
+		unlock_page(vmpage);
+	cfio->fault.ft_flags &= ~VM_FAULT_LOCKED;
+	return result;
+}
+
+static int vvp_io_fsync_start(const struct lu_env *env,
+			      const struct cl_io_slice *ios)
+{
+	/* we should mark TOWRITE bit to each dirty page in radix tree to
+	 * verify pages have been written, but this is difficult because of
+	 * race. */
+	return 0;
+}
+
+static int vvp_io_read_page(const struct lu_env *env,
+			    const struct cl_io_slice *ios,
+			    const struct cl_page_slice *slice)
+{
+	struct cl_io	      *io     = ios->cis_io;
+	struct cl_object	  *obj    = slice->cpl_obj;
+	struct ccc_page	   *cp     = cl2ccc_page(slice);
+	struct cl_page	    *page   = slice->cpl_page;
+	struct inode	      *inode  = ccc_object_inode(obj);
+	struct ll_sb_info	 *sbi    = ll_i2sbi(inode);
+	struct ll_file_data       *fd     = cl2ccc_io(env, ios)->cui_fd;
+	struct ll_readahead_state *ras    = &fd->fd_ras;
+	struct page		*vmpage = cp->cpg_page;
+	struct cl_2queue	  *queue  = &io->ci_queue;
+	int rc;
+
+	CLOBINVRNT(env, obj, ccc_object_invariant(obj));
+	LASSERT(slice->cpl_obj == obj);
+
+	ENTRY;
+
+	if (sbi->ll_ra_info.ra_max_pages_per_file &&
+	    sbi->ll_ra_info.ra_max_pages)
+		ras_update(sbi, inode, ras, page->cp_index,
+			   cp->cpg_defer_uptodate);
+
+	/* Sanity check whether the page is protected by a lock. */
+	rc = cl_page_is_under_lock(env, io, page);
+	if (rc != -EBUSY) {
+		CL_PAGE_HEADER(D_WARNING, env, page, "%s: %d\n",
+			       rc == -ENODATA ? "without a lock" :
+			       "match failed", rc);
+		if (rc != -ENODATA)
+			RETURN(rc);
+	}
+
+	if (cp->cpg_defer_uptodate) {
+		cp->cpg_ra_used = 1;
+		cl_page_export(env, page, 1);
+	}
+	/*
+	 * Add page into the queue even when it is marked uptodate above.
+	 * this will unlock it automatically as part of cl_page_list_disown().
+	 */
+	cl_2queue_add(queue, page);
+	if (sbi->ll_ra_info.ra_max_pages_per_file &&
+	    sbi->ll_ra_info.ra_max_pages)
+		ll_readahead(env, io, ras,
+			     vmpage->mapping, &queue->c2_qin, fd->fd_flags);
+
+	RETURN(0);
+}
+
+static int vvp_page_sync_io(const struct lu_env *env, struct cl_io *io,
+			    struct cl_page *page, struct ccc_page *cp,
+			    enum cl_req_type crt)
+{
+	struct cl_2queue  *queue;
+	int result;
+
+	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
+
+	queue = &io->ci_queue;
+	cl_2queue_init_page(queue, page);
+
+	result = cl_io_submit_sync(env, io, crt, queue, 0);
+	LASSERT(cl_page_is_owned(page, io));
+
+	if (crt == CRT_READ)
+		/*
+		 * in CRT_WRITE case page is left locked even in case of
+		 * error.
+		 */
+		cl_page_list_disown(env, io, &queue->c2_qin);
+	cl_2queue_fini(env, queue);
+
+	return result;
+}
+
+/**
+ * Prepare partially written-to page for a write.
+ */
+static int vvp_io_prepare_partial(const struct lu_env *env, struct cl_io *io,
+				  struct cl_object *obj, struct cl_page *pg,
+				  struct ccc_page *cp,
+				  unsigned from, unsigned to)
+{
+	struct cl_attr *attr   = ccc_env_thread_attr(env);
+	loff_t	  offset = cl_offset(obj, pg->cp_index);
+	int	     result;
+
+	cl_object_attr_lock(obj);
+	result = cl_object_attr_get(env, obj, attr);
+	cl_object_attr_unlock(obj);
+	if (result == 0) {
+		/*
+		 * If are writing to a new page, no need to read old data.
+		 * The extent locking will have updated the KMS, and for our
+		 * purposes here we can treat it like i_size.
+		 */
+		if (attr->cat_kms <= offset) {
+			char *kaddr = ll_kmap_atomic(cp->cpg_page, KM_USER0);
+
+			memset(kaddr, 0, cl_page_size(obj));
+			ll_kunmap_atomic(kaddr, KM_USER0);
+		} else if (cp->cpg_defer_uptodate)
+			cp->cpg_ra_used = 1;
+		else
+			result = vvp_page_sync_io(env, io, pg, cp, CRT_READ);
+		/*
+		 * In older implementations, obdo_refresh_inode is called here
+		 * to update the inode because the write might modify the
+		 * object info at OST. However, this has been proven useless,
+		 * since LVB functions will be called when user space program
+		 * tries to retrieve inode attribute.  Also, see bug 15909 for
+		 * details. -jay
+		 */
+		if (result == 0)
+			cl_page_export(env, pg, 1);
+	}
+	return result;
+}
+
+static int vvp_io_prepare_write(const struct lu_env *env,
+				const struct cl_io_slice *ios,
+				const struct cl_page_slice *slice,
+				unsigned from, unsigned to)
+{
+	struct cl_object *obj    = slice->cpl_obj;
+	struct ccc_page  *cp     = cl2ccc_page(slice);
+	struct cl_page   *pg     = slice->cpl_page;
+	struct page       *vmpage = cp->cpg_page;
+
+	int result;
+
+	ENTRY;
+
+	LINVRNT(cl_page_is_vmlocked(env, pg));
+	LASSERT(vmpage->mapping->host == ccc_object_inode(obj));
+
+	result = 0;
+
+	CL_PAGE_HEADER(D_PAGE, env, pg, "preparing: [%d, %d]\n", from, to);
+	if (!PageUptodate(vmpage)) {
+		/*
+		 * We're completely overwriting an existing page, so _don't_
+		 * set it up to date until commit_write
+		 */
+		if (from == 0 && to == PAGE_CACHE_SIZE) {
+			CL_PAGE_HEADER(D_PAGE, env, pg, "full page write\n");
+			POISON_PAGE(page, 0x11);
+		} else
+			result = vvp_io_prepare_partial(env, ios->cis_io, obj,
+							pg, cp, from, to);
+	} else
+		CL_PAGE_HEADER(D_PAGE, env, pg, "uptodate\n");
+	RETURN(result);
+}
+
+static int vvp_io_commit_write(const struct lu_env *env,
+			       const struct cl_io_slice *ios,
+			       const struct cl_page_slice *slice,
+			       unsigned from, unsigned to)
+{
+	struct cl_object  *obj    = slice->cpl_obj;
+	struct cl_io      *io     = ios->cis_io;
+	struct ccc_page   *cp     = cl2ccc_page(slice);
+	struct cl_page    *pg     = slice->cpl_page;
+	struct inode      *inode  = ccc_object_inode(obj);
+	struct ll_sb_info *sbi    = ll_i2sbi(inode);
+	struct ll_inode_info *lli = ll_i2info(inode);
+	struct page	*vmpage = cp->cpg_page;
+
+	int    result;
+	int    tallyop;
+	loff_t size;
+
+	ENTRY;
+
+	LINVRNT(cl_page_is_vmlocked(env, pg));
+	LASSERT(vmpage->mapping->host == inode);
+
+	LU_OBJECT_HEADER(D_INODE, env, &obj->co_lu, "commiting page write\n");
+	CL_PAGE_HEADER(D_PAGE, env, pg, "committing: [%d, %d]\n", from, to);
+
+	/*
+	 * queue a write for some time in the future the first time we
+	 * dirty the page.
+	 *
+	 * This is different from what other file systems do: they usually
+	 * just mark page (and some of its buffers) dirty and rely on
+	 * balance_dirty_pages() to start a write-back. Lustre wants write-back
+	 * to be started earlier for the following reasons:
+	 *
+	 *     (1) with a large number of clients we need to limit the amount
+	 *     of cached data on the clients a lot;
+	 *
+	 *     (2) large compute jobs generally want compute-only then io-only
+	 *     and the IO should complete as quickly as possible;
+	 *
+	 *     (3) IO is batched up to the RPC size and is async until the
+	 *     client max cache is hit
+	 *     (/proc/fs/lustre/osc/OSC.../max_dirty_mb)
+	 *
+	 */
+	if (!PageDirty(vmpage)) {
+		tallyop = LPROC_LL_DIRTY_MISSES;
+		result = cl_page_cache_add(env, io, pg, CRT_WRITE);
+		if (result == 0) {
+			/* page was added into cache successfully. */
+			set_page_dirty(vmpage);
+			vvp_write_pending(cl2ccc(obj), cp);
+		} else if (result == -EDQUOT) {
+			pgoff_t last_index = i_size_read(inode) >> PAGE_CACHE_SHIFT;
+			bool need_clip = true;
+
+			/*
+			 * Client ran out of disk space grant. Possible
+			 * strategies are:
+			 *
+			 *     (a) do a sync write, renewing grant;
+			 *
+			 *     (b) stop writing on this stripe, switch to the
+			 *     next one.
+			 *
+			 * (b) is a part of "parallel io" design that is the
+			 * ultimate goal. (a) is what "old" client did, and
+			 * what the new code continues to do for the time
+			 * being.
+			 */
+			if (last_index > pg->cp_index) {
+				to = PAGE_CACHE_SIZE;
+				need_clip = false;
+			} else if (last_index == pg->cp_index) {
+				int size_to = i_size_read(inode) & ~CFS_PAGE_MASK;
+				if (to < size_to)
+					to = size_to;
+			}
+			if (need_clip)
+				cl_page_clip(env, pg, 0, to);
+			result = vvp_page_sync_io(env, io, pg, cp, CRT_WRITE);
+			if (result)
+				CERROR("Write page %lu of inode %p failed %d\n",
+				       pg->cp_index, inode, result);
+		}
+	} else {
+		tallyop = LPROC_LL_DIRTY_HITS;
+		result = 0;
+	}
+	ll_stats_ops_tally(sbi, tallyop, 1);
+
+	/* Inode should be marked DIRTY even if no new page was marked DIRTY
+	 * because page could have been not flushed between 2 modifications.
+	 * It is important the file is marked DIRTY as soon as the I/O is done
+	 * Indeed, when cache is flushed, file could be already closed and it
+	 * is too late to warn the MDT.
+	 * It is acceptable that file is marked DIRTY even if I/O is dropped
+	 * for some reasons before being flushed to OST.
+	 */
+	if (result == 0) {
+		spin_lock(&lli->lli_lock);
+		lli->lli_flags |= LLIF_DATA_MODIFIED;
+		spin_unlock(&lli->lli_lock);
+	}
+
+	size = cl_offset(obj, pg->cp_index) + to;
+
+	ll_inode_size_lock(inode);
+	if (result == 0) {
+		if (size > i_size_read(inode)) {
+			cl_isize_write_nolock(inode, size);
+			CDEBUG(D_VFSTRACE, DFID" updating i_size %lu\n",
+			       PFID(lu_object_fid(&obj->co_lu)),
+			       (unsigned long)size);
+		}
+		cl_page_export(env, pg, 1);
+	} else {
+		if (size > i_size_read(inode))
+			cl_page_discard(env, io, pg);
+	}
+	ll_inode_size_unlock(inode);
+	RETURN(result);
+}
+
+static const struct cl_io_operations vvp_io_ops = {
+	.op = {
+		[CIT_READ] = {
+			.cio_fini      = vvp_io_read_fini,
+			.cio_lock      = vvp_io_read_lock,
+			.cio_start     = vvp_io_read_start,
+			.cio_advance   = ccc_io_advance
+		},
+		[CIT_WRITE] = {
+			.cio_fini      = vvp_io_fini,
+			.cio_lock      = vvp_io_write_lock,
+			.cio_start     = vvp_io_write_start,
+			.cio_advance   = ccc_io_advance
+		},
+		[CIT_SETATTR] = {
+			.cio_fini       = vvp_io_setattr_fini,
+			.cio_iter_init  = vvp_io_setattr_iter_init,
+			.cio_lock       = vvp_io_setattr_lock,
+			.cio_start      = vvp_io_setattr_start,
+			.cio_end	= vvp_io_setattr_end
+		},
+		[CIT_FAULT] = {
+			.cio_fini      = vvp_io_fault_fini,
+			.cio_iter_init = vvp_io_fault_iter_init,
+			.cio_lock      = vvp_io_fault_lock,
+			.cio_start     = vvp_io_fault_start,
+			.cio_end       = ccc_io_end
+		},
+		[CIT_FSYNC] = {
+			.cio_start  = vvp_io_fsync_start,
+			.cio_fini   = vvp_io_fini
+		},
+		[CIT_MISC] = {
+			.cio_fini   = vvp_io_fini
+		}
+	},
+	.cio_read_page     = vvp_io_read_page,
+	.cio_prepare_write = vvp_io_prepare_write,
+	.cio_commit_write  = vvp_io_commit_write
+};
+
+int vvp_io_init(const struct lu_env *env, struct cl_object *obj,
+		struct cl_io *io)
+{
+	struct vvp_io      *vio   = vvp_env_io(env);
+	struct ccc_io      *cio   = ccc_env_io(env);
+	struct inode       *inode = ccc_object_inode(obj);
+	int		 result;
+
+	CLOBINVRNT(env, obj, ccc_object_invariant(obj));
+	ENTRY;
+
+	CL_IO_SLICE_CLEAN(cio, cui_cl);
+	cl_io_slice_add(io, &cio->cui_cl, obj, &vvp_io_ops);
+	vio->cui_ra_window_set = 0;
+	result = 0;
+	if (io->ci_type == CIT_READ || io->ci_type == CIT_WRITE) {
+		size_t count;
+		struct ll_inode_info *lli = ll_i2info(inode);
+
+		count = io->u.ci_rw.crw_count;
+		/* "If nbyte is 0, read() will return 0 and have no other
+		 *  results."  -- Single Unix Spec */
+		if (count == 0)
+			result = 1;
+		else {
+			cio->cui_tot_count = count;
+			cio->cui_tot_nrsegs = 0;
+		}
+		/* for read/write, we store the jobid in the inode, and
+		 * it'll be fetched by osc when building RPC.
+		 *
+		 * it's not accurate if the file is shared by different
+		 * jobs.
+		 */
+		lustre_get_jobid(lli->lli_jobid);
+	} else if (io->ci_type == CIT_SETATTR) {
+		if (!cl_io_is_trunc(io))
+			io->ci_lockreq = CILR_MANDATORY;
+	}
+
+	/* ignore layout change for generic CIT_MISC but not for glimpse.
+	 * io context for glimpse must set ci_verify_layout to true,
+	 * see cl_glimpse_size0() for details. */
+	if (io->ci_type == CIT_MISC && !io->ci_verify_layout)
+		io->ci_ignore_layout = 1;
+
+	/* Enqueue layout lock and get layout version. We need to do this
+	 * even for operations requiring to open file, such as read and write,
+	 * because it might not grant layout lock in IT_OPEN. */
+	if (result == 0 && !io->ci_ignore_layout)
+		result = ll_layout_refresh(inode, &cio->cui_layout_gen);
+
+	RETURN(result);
+}
+
+static struct vvp_io *cl2vvp_io(const struct lu_env *env,
+				const struct cl_io_slice *slice)
+{
+	/* Caling just for assertion */
+	cl2ccc_io(env, slice);
+	return vvp_env_io(env);
+}