X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fstaging%2Flustre%2Flustre%2Flov%2Flov_io.c;fp=kernel%2Fdrivers%2Fstaging%2Flustre%2Flustre%2Flov%2Flov_io.c;h=cf96e0d01e22d5d000304d46a24cc75ff2596a8e;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git

diff --git a/kernel/drivers/staging/lustre/lustre/lov/lov_io.c b/kernel/drivers/staging/lustre/lustre/lov/lov_io.c
new file mode 100644
index 000000000..cf96e0d01
--- /dev/null
+++ b/kernel/drivers/staging/lustre/lustre/lov/lov_io.c
@@ -0,0 +1,990 @@
+/*
+ * 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 LOV layer.
+ *
+ *   Author: Nikita Danilov <nikita.danilov@sun.com>
+ *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
+ */
+
+#define DEBUG_SUBSYSTEM S_LOV
+
+#include "lov_cl_internal.h"
+
+/** \addtogroup lov
+ *  @{
+ */
+
+static inline void lov_sub_enter(struct lov_io_sub *sub)
+{
+	sub->sub_reenter++;
+}
+static inline void lov_sub_exit(struct lov_io_sub *sub)
+{
+	sub->sub_reenter--;
+}
+
+static void lov_io_sub_fini(const struct lu_env *env, struct lov_io *lio,
+			    struct lov_io_sub *sub)
+{
+	if (sub->sub_io != NULL) {
+		if (sub->sub_io_initialized) {
+			lov_sub_enter(sub);
+			cl_io_fini(sub->sub_env, sub->sub_io);
+			lov_sub_exit(sub);
+			sub->sub_io_initialized = 0;
+			lio->lis_active_subios--;
+		}
+		if (sub->sub_stripe == lio->lis_single_subio_index)
+			lio->lis_single_subio_index = -1;
+		else if (!sub->sub_borrowed)
+			OBD_FREE_PTR(sub->sub_io);
+		sub->sub_io = NULL;
+	}
+	if (sub->sub_env != NULL && !IS_ERR(sub->sub_env)) {
+		if (!sub->sub_borrowed)
+			cl_env_put(sub->sub_env, &sub->sub_refcheck);
+		sub->sub_env = NULL;
+	}
+}
+
+static void lov_io_sub_inherit(struct cl_io *io, struct lov_io *lio,
+			       int stripe, loff_t start, loff_t end)
+{
+	struct lov_stripe_md *lsm    = lio->lis_object->lo_lsm;
+	struct cl_io	 *parent = lio->lis_cl.cis_io;
+
+	switch (io->ci_type) {
+	case CIT_SETATTR: {
+		io->u.ci_setattr.sa_attr = parent->u.ci_setattr.sa_attr;
+		io->u.ci_setattr.sa_valid = parent->u.ci_setattr.sa_valid;
+		io->u.ci_setattr.sa_capa = parent->u.ci_setattr.sa_capa;
+		if (cl_io_is_trunc(io)) {
+			loff_t new_size = parent->u.ci_setattr.sa_attr.lvb_size;
+
+			new_size = lov_size_to_stripe(lsm, new_size, stripe);
+			io->u.ci_setattr.sa_attr.lvb_size = new_size;
+		}
+		break;
+	}
+	case CIT_FAULT: {
+		struct cl_object *obj = parent->ci_obj;
+		loff_t off = cl_offset(obj, parent->u.ci_fault.ft_index);
+
+		io->u.ci_fault = parent->u.ci_fault;
+		off = lov_size_to_stripe(lsm, off, stripe);
+		io->u.ci_fault.ft_index = cl_index(obj, off);
+		break;
+	}
+	case CIT_FSYNC: {
+		io->u.ci_fsync.fi_start = start;
+		io->u.ci_fsync.fi_end = end;
+		io->u.ci_fsync.fi_capa = parent->u.ci_fsync.fi_capa;
+		io->u.ci_fsync.fi_fid = parent->u.ci_fsync.fi_fid;
+		io->u.ci_fsync.fi_mode = parent->u.ci_fsync.fi_mode;
+		break;
+	}
+	case CIT_READ:
+	case CIT_WRITE: {
+		io->u.ci_wr.wr_sync = cl_io_is_sync_write(parent);
+		if (cl_io_is_append(parent)) {
+			io->u.ci_wr.wr_append = 1;
+		} else {
+			io->u.ci_rw.crw_pos = start;
+			io->u.ci_rw.crw_count = end - start;
+		}
+		break;
+	}
+	default:
+		break;
+	}
+}
+
+static int lov_io_sub_init(const struct lu_env *env, struct lov_io *lio,
+			   struct lov_io_sub *sub)
+{
+	struct lov_object *lov = lio->lis_object;
+	struct lov_device *ld  = lu2lov_dev(lov2cl(lov)->co_lu.lo_dev);
+	struct cl_io      *sub_io;
+	struct cl_object  *sub_obj;
+	struct cl_io      *io  = lio->lis_cl.cis_io;
+
+	int stripe = sub->sub_stripe;
+	int result;
+
+	LASSERT(sub->sub_io == NULL);
+	LASSERT(sub->sub_env == NULL);
+	LASSERT(sub->sub_stripe < lio->lis_stripe_count);
+
+	if (unlikely(lov_r0(lov)->lo_sub[stripe] == NULL))
+		return -EIO;
+
+	result = 0;
+	sub->sub_io_initialized = 0;
+	sub->sub_borrowed = 0;
+
+	if (lio->lis_mem_frozen) {
+		LASSERT(mutex_is_locked(&ld->ld_mutex));
+		sub->sub_io  = &ld->ld_emrg[stripe]->emrg_subio;
+		sub->sub_env = ld->ld_emrg[stripe]->emrg_env;
+		sub->sub_borrowed = 1;
+	} else {
+		void *cookie;
+
+		/* obtain new environment */
+		cookie = cl_env_reenter();
+		sub->sub_env = cl_env_get(&sub->sub_refcheck);
+		cl_env_reexit(cookie);
+		if (IS_ERR(sub->sub_env))
+			result = PTR_ERR(sub->sub_env);
+
+		if (result == 0) {
+			/*
+			 * First sub-io. Use ->lis_single_subio to
+			 * avoid dynamic allocation.
+			 */
+			if (lio->lis_active_subios == 0) {
+				sub->sub_io = &lio->lis_single_subio;
+				lio->lis_single_subio_index = stripe;
+			} else {
+				OBD_ALLOC_PTR(sub->sub_io);
+				if (sub->sub_io == NULL)
+					result = -ENOMEM;
+			}
+		}
+	}
+
+	if (result == 0) {
+		sub_obj = lovsub2cl(lov_r0(lov)->lo_sub[stripe]);
+		sub_io  = sub->sub_io;
+
+		sub_io->ci_obj    = sub_obj;
+		sub_io->ci_result = 0;
+
+		sub_io->ci_parent  = io;
+		sub_io->ci_lockreq = io->ci_lockreq;
+		sub_io->ci_type    = io->ci_type;
+		sub_io->ci_no_srvlock = io->ci_no_srvlock;
+		sub_io->ci_noatime = io->ci_noatime;
+
+		lov_sub_enter(sub);
+		result = cl_io_sub_init(sub->sub_env, sub_io,
+					io->ci_type, sub_obj);
+		lov_sub_exit(sub);
+		if (result >= 0) {
+			lio->lis_active_subios++;
+			sub->sub_io_initialized = 1;
+			result = 0;
+		}
+	}
+	if (result != 0)
+		lov_io_sub_fini(env, lio, sub);
+	return result;
+}
+
+struct lov_io_sub *lov_sub_get(const struct lu_env *env,
+			       struct lov_io *lio, int stripe)
+{
+	int rc;
+	struct lov_io_sub *sub = &lio->lis_subs[stripe];
+
+	LASSERT(stripe < lio->lis_stripe_count);
+
+	if (!sub->sub_io_initialized) {
+		sub->sub_stripe = stripe;
+		rc = lov_io_sub_init(env, lio, sub);
+	} else
+		rc = 0;
+	if (rc == 0)
+		lov_sub_enter(sub);
+	else
+		sub = ERR_PTR(rc);
+	return sub;
+}
+
+void lov_sub_put(struct lov_io_sub *sub)
+{
+	lov_sub_exit(sub);
+}
+
+/*****************************************************************************
+ *
+ * Lov io operations.
+ *
+ */
+
+static int lov_page_stripe(const struct cl_page *page)
+{
+	struct lovsub_object *subobj;
+
+	subobj = lu2lovsub(
+		lu_object_locate(page->cp_child->cp_obj->co_lu.lo_header,
+				 &lovsub_device_type));
+	LASSERT(subobj != NULL);
+	return subobj->lso_index;
+}
+
+struct lov_io_sub *lov_page_subio(const struct lu_env *env, struct lov_io *lio,
+				  const struct cl_page_slice *slice)
+{
+	struct lov_stripe_md *lsm  = lio->lis_object->lo_lsm;
+	struct cl_page       *page = slice->cpl_page;
+	int stripe;
+
+	LASSERT(lio->lis_cl.cis_io != NULL);
+	LASSERT(cl2lov(slice->cpl_obj) == lio->lis_object);
+	LASSERT(lsm != NULL);
+	LASSERT(lio->lis_nr_subios > 0);
+
+	stripe = lov_page_stripe(page);
+	return lov_sub_get(env, lio, stripe);
+}
+
+
+static int lov_io_subio_init(const struct lu_env *env, struct lov_io *lio,
+			     struct cl_io *io)
+{
+	struct lov_stripe_md *lsm = lio->lis_object->lo_lsm;
+	int result;
+
+	LASSERT(lio->lis_object != NULL);
+
+	/*
+	 * Need to be optimized, we can't afford to allocate a piece of memory
+	 * when writing a page. -jay
+	 */
+	OBD_ALLOC_LARGE(lio->lis_subs,
+			lsm->lsm_stripe_count * sizeof(lio->lis_subs[0]));
+	if (lio->lis_subs != NULL) {
+		lio->lis_nr_subios = lio->lis_stripe_count;
+		lio->lis_single_subio_index = -1;
+		lio->lis_active_subios = 0;
+		result = 0;
+	} else
+		result = -ENOMEM;
+	return result;
+}
+
+static void lov_io_slice_init(struct lov_io *lio,
+			      struct lov_object *obj, struct cl_io *io)
+{
+	io->ci_result = 0;
+	lio->lis_object = obj;
+
+	LASSERT(obj->lo_lsm != NULL);
+	lio->lis_stripe_count = obj->lo_lsm->lsm_stripe_count;
+
+	switch (io->ci_type) {
+	case CIT_READ:
+	case CIT_WRITE:
+		lio->lis_pos = io->u.ci_rw.crw_pos;
+		lio->lis_endpos = io->u.ci_rw.crw_pos + io->u.ci_rw.crw_count;
+		lio->lis_io_endpos = lio->lis_endpos;
+		if (cl_io_is_append(io)) {
+			LASSERT(io->ci_type == CIT_WRITE);
+			lio->lis_pos = 0;
+			lio->lis_endpos = OBD_OBJECT_EOF;
+		}
+		break;
+
+	case CIT_SETATTR:
+		if (cl_io_is_trunc(io))
+			lio->lis_pos = io->u.ci_setattr.sa_attr.lvb_size;
+		else
+			lio->lis_pos = 0;
+		lio->lis_endpos = OBD_OBJECT_EOF;
+		break;
+
+	case CIT_FAULT: {
+		pgoff_t index = io->u.ci_fault.ft_index;
+		lio->lis_pos = cl_offset(io->ci_obj, index);
+		lio->lis_endpos = cl_offset(io->ci_obj, index + 1);
+		break;
+	}
+
+	case CIT_FSYNC: {
+		lio->lis_pos = io->u.ci_fsync.fi_start;
+		lio->lis_endpos = io->u.ci_fsync.fi_end;
+		break;
+	}
+
+	case CIT_MISC:
+		lio->lis_pos = 0;
+		lio->lis_endpos = OBD_OBJECT_EOF;
+		break;
+
+	default:
+		LBUG();
+	}
+}
+
+static void lov_io_fini(const struct lu_env *env, const struct cl_io_slice *ios)
+{
+	struct lov_io *lio = cl2lov_io(env, ios);
+	struct lov_object *lov = cl2lov(ios->cis_obj);
+	int i;
+
+	if (lio->lis_subs != NULL) {
+		for (i = 0; i < lio->lis_nr_subios; i++)
+			lov_io_sub_fini(env, lio, &lio->lis_subs[i]);
+		OBD_FREE_LARGE(lio->lis_subs,
+			 lio->lis_nr_subios * sizeof(lio->lis_subs[0]));
+		lio->lis_nr_subios = 0;
+	}
+
+	LASSERT(atomic_read(&lov->lo_active_ios) > 0);
+	if (atomic_dec_and_test(&lov->lo_active_ios))
+		wake_up_all(&lov->lo_waitq);
+}
+
+static u64 lov_offset_mod(u64 val, int delta)
+{
+	if (val != OBD_OBJECT_EOF)
+		val += delta;
+	return val;
+}
+
+static int lov_io_iter_init(const struct lu_env *env,
+			    const struct cl_io_slice *ios)
+{
+	struct lov_io	*lio = cl2lov_io(env, ios);
+	struct lov_stripe_md *lsm = lio->lis_object->lo_lsm;
+	struct lov_io_sub    *sub;
+	u64 endpos;
+	u64 start;
+	u64 end;
+	int stripe;
+	int rc = 0;
+
+	endpos = lov_offset_mod(lio->lis_endpos, -1);
+	for (stripe = 0; stripe < lio->lis_stripe_count; stripe++) {
+		if (!lov_stripe_intersects(lsm, stripe, lio->lis_pos,
+					   endpos, &start, &end))
+			continue;
+
+		if (unlikely(lov_r0(lio->lis_object)->lo_sub[stripe] == NULL)) {
+			if (ios->cis_io->ci_type == CIT_READ ||
+			    ios->cis_io->ci_type == CIT_WRITE ||
+			    ios->cis_io->ci_type == CIT_FAULT)
+				return -EIO;
+
+			continue;
+		}
+
+		end = lov_offset_mod(end, 1);
+		sub = lov_sub_get(env, lio, stripe);
+		if (!IS_ERR(sub)) {
+			lov_io_sub_inherit(sub->sub_io, lio, stripe,
+					   start, end);
+			rc = cl_io_iter_init(sub->sub_env, sub->sub_io);
+			lov_sub_put(sub);
+			CDEBUG(D_VFSTRACE, "shrink: %d [%llu, %llu)\n",
+			       stripe, start, end);
+		} else
+			rc = PTR_ERR(sub);
+
+		if (!rc)
+			list_add_tail(&sub->sub_linkage, &lio->lis_active);
+		else
+			break;
+	}
+	return rc;
+}
+
+static int lov_io_rw_iter_init(const struct lu_env *env,
+			       const struct cl_io_slice *ios)
+{
+	struct lov_io	*lio = cl2lov_io(env, ios);
+	struct cl_io	 *io  = ios->cis_io;
+	struct lov_stripe_md *lsm = lio->lis_object->lo_lsm;
+	__u64 start = io->u.ci_rw.crw_pos;
+	loff_t next;
+	unsigned long ssize = lsm->lsm_stripe_size;
+
+	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
+
+	/* fast path for common case. */
+	if (lio->lis_nr_subios != 1 && !cl_io_is_append(io)) {
+
+		lov_do_div64(start, ssize);
+		next = (start + 1) * ssize;
+		if (next <= start * ssize)
+			next = ~0ull;
+
+		io->ci_continue = next < lio->lis_io_endpos;
+		io->u.ci_rw.crw_count = min_t(loff_t, lio->lis_io_endpos,
+					      next) - io->u.ci_rw.crw_pos;
+		lio->lis_pos    = io->u.ci_rw.crw_pos;
+		lio->lis_endpos = io->u.ci_rw.crw_pos + io->u.ci_rw.crw_count;
+		CDEBUG(D_VFSTRACE, "stripe: %llu chunk: [%llu, %llu) %llu\n",
+		       (__u64)start, lio->lis_pos, lio->lis_endpos,
+		       (__u64)lio->lis_io_endpos);
+	}
+	/*
+	 * XXX The following call should be optimized: we know, that
+	 * [lio->lis_pos, lio->lis_endpos) intersects with exactly one stripe.
+	 */
+	return lov_io_iter_init(env, ios);
+}
+
+static int lov_io_call(const struct lu_env *env, struct lov_io *lio,
+		       int (*iofunc)(const struct lu_env *, struct cl_io *))
+{
+	struct cl_io *parent = lio->lis_cl.cis_io;
+	struct lov_io_sub *sub;
+	int rc = 0;
+
+	list_for_each_entry(sub, &lio->lis_active, sub_linkage) {
+		lov_sub_enter(sub);
+		rc = iofunc(sub->sub_env, sub->sub_io);
+		lov_sub_exit(sub);
+		if (rc)
+			break;
+
+		if (parent->ci_result == 0)
+			parent->ci_result = sub->sub_io->ci_result;
+	}
+	return rc;
+}
+
+static int lov_io_lock(const struct lu_env *env, const struct cl_io_slice *ios)
+{
+	return lov_io_call(env, cl2lov_io(env, ios), cl_io_lock);
+}
+
+static int lov_io_start(const struct lu_env *env, const struct cl_io_slice *ios)
+{
+	return lov_io_call(env, cl2lov_io(env, ios), cl_io_start);
+}
+
+static int lov_io_end_wrapper(const struct lu_env *env, struct cl_io *io)
+{
+	/*
+	 * It's possible that lov_io_start() wasn't called against this
+	 * sub-io, either because previous sub-io failed, or upper layer
+	 * completed IO.
+	 */
+	if (io->ci_state == CIS_IO_GOING)
+		cl_io_end(env, io);
+	else
+		io->ci_state = CIS_IO_FINISHED;
+	return 0;
+}
+
+static int lov_io_iter_fini_wrapper(const struct lu_env *env, struct cl_io *io)
+{
+	cl_io_iter_fini(env, io);
+	return 0;
+}
+
+static int lov_io_unlock_wrapper(const struct lu_env *env, struct cl_io *io)
+{
+	cl_io_unlock(env, io);
+	return 0;
+}
+
+static void lov_io_end(const struct lu_env *env, const struct cl_io_slice *ios)
+{
+	int rc;
+
+	rc = lov_io_call(env, cl2lov_io(env, ios), lov_io_end_wrapper);
+	LASSERT(rc == 0);
+}
+
+static void lov_io_iter_fini(const struct lu_env *env,
+			     const struct cl_io_slice *ios)
+{
+	struct lov_io *lio = cl2lov_io(env, ios);
+	int rc;
+
+	rc = lov_io_call(env, lio, lov_io_iter_fini_wrapper);
+	LASSERT(rc == 0);
+	while (!list_empty(&lio->lis_active))
+		list_del_init(lio->lis_active.next);
+}
+
+static void lov_io_unlock(const struct lu_env *env,
+			  const struct cl_io_slice *ios)
+{
+	int rc;
+
+	rc = lov_io_call(env, cl2lov_io(env, ios), lov_io_unlock_wrapper);
+	LASSERT(rc == 0);
+}
+
+
+static struct cl_page_list *lov_io_submit_qin(struct lov_device *ld,
+					      struct cl_page_list *qin,
+					      int idx, int alloc)
+{
+	return alloc ? &qin[idx] : &ld->ld_emrg[idx]->emrg_page_list;
+}
+
+/**
+ * lov implementation of cl_operations::cio_submit() method. It takes a list
+ * of pages in \a queue, splits it into per-stripe sub-lists, invokes
+ * cl_io_submit() on underlying devices to submit sub-lists, and then splices
+ * everything back.
+ *
+ * Major complication of this function is a need to handle memory cleansing:
+ * cl_io_submit() is called to write out pages as a part of VM memory
+ * reclamation, and hence it may not fail due to memory shortages (system
+ * dead-locks otherwise). To deal with this, some resources (sub-lists,
+ * sub-environment, etc.) are allocated per-device on "startup" (i.e., in a
+ * not-memory cleansing context), and in case of memory shortage, these
+ * pre-allocated resources are used by lov_io_submit() under
+ * lov_device::ld_mutex mutex.
+ */
+static int lov_io_submit(const struct lu_env *env,
+			 const struct cl_io_slice *ios,
+			 enum cl_req_type crt, struct cl_2queue *queue)
+{
+	struct lov_io	  *lio = cl2lov_io(env, ios);
+	struct lov_object      *obj = lio->lis_object;
+	struct lov_device       *ld = lu2lov_dev(lov2cl(obj)->co_lu.lo_dev);
+	struct cl_page_list    *qin = &queue->c2_qin;
+	struct cl_2queue      *cl2q = &lov_env_info(env)->lti_cl2q;
+	struct cl_page_list *stripes_qin = NULL;
+	struct cl_page *page;
+	struct cl_page *tmp;
+	int stripe;
+
+#define QIN(stripe) lov_io_submit_qin(ld, stripes_qin, stripe, alloc)
+
+	int rc = 0;
+	int alloc =
+		!(current->flags & PF_MEMALLOC);
+
+	if (lio->lis_active_subios == 1) {
+		int idx = lio->lis_single_subio_index;
+		struct lov_io_sub *sub;
+
+		LASSERT(idx < lio->lis_nr_subios);
+		sub = lov_sub_get(env, lio, idx);
+		LASSERT(!IS_ERR(sub));
+		LASSERT(sub->sub_io == &lio->lis_single_subio);
+		rc = cl_io_submit_rw(sub->sub_env, sub->sub_io,
+				     crt, queue);
+		lov_sub_put(sub);
+		return rc;
+	}
+
+	LASSERT(lio->lis_subs != NULL);
+	if (alloc) {
+		OBD_ALLOC_LARGE(stripes_qin,
+				sizeof(*stripes_qin) * lio->lis_nr_subios);
+		if (stripes_qin == NULL)
+			return -ENOMEM;
+
+		for (stripe = 0; stripe < lio->lis_nr_subios; stripe++)
+			cl_page_list_init(&stripes_qin[stripe]);
+	} else {
+		/*
+		 * If we get here, it means pageout & swap doesn't help.
+		 * In order to not make things worse, even don't try to
+		 * allocate the memory with __GFP_NOWARN. -jay
+		 */
+		mutex_lock(&ld->ld_mutex);
+		lio->lis_mem_frozen = 1;
+	}
+
+	cl_2queue_init(cl2q);
+	cl_page_list_for_each_safe(page, tmp, qin) {
+		stripe = lov_page_stripe(page);
+		cl_page_list_move(QIN(stripe), qin, page);
+	}
+
+	for (stripe = 0; stripe < lio->lis_nr_subios; stripe++) {
+		struct lov_io_sub   *sub;
+		struct cl_page_list *sub_qin = QIN(stripe);
+
+		if (list_empty(&sub_qin->pl_pages))
+			continue;
+
+		cl_page_list_splice(sub_qin, &cl2q->c2_qin);
+		sub = lov_sub_get(env, lio, stripe);
+		if (!IS_ERR(sub)) {
+			rc = cl_io_submit_rw(sub->sub_env, sub->sub_io,
+					     crt, cl2q);
+			lov_sub_put(sub);
+		} else
+			rc = PTR_ERR(sub);
+		cl_page_list_splice(&cl2q->c2_qin,  &queue->c2_qin);
+		cl_page_list_splice(&cl2q->c2_qout, &queue->c2_qout);
+		if (rc != 0)
+			break;
+	}
+
+	for (stripe = 0; stripe < lio->lis_nr_subios; stripe++) {
+		struct cl_page_list *sub_qin = QIN(stripe);
+
+		if (list_empty(&sub_qin->pl_pages))
+			continue;
+
+		cl_page_list_splice(sub_qin, qin);
+	}
+
+	if (alloc) {
+		OBD_FREE_LARGE(stripes_qin,
+			 sizeof(*stripes_qin) * lio->lis_nr_subios);
+	} else {
+		int i;
+
+		for (i = 0; i < lio->lis_nr_subios; i++) {
+			struct cl_io *cio = lio->lis_subs[i].sub_io;
+
+			if (cio && cio == &ld->ld_emrg[i]->emrg_subio)
+				lov_io_sub_fini(env, lio, &lio->lis_subs[i]);
+		}
+		lio->lis_mem_frozen = 0;
+		mutex_unlock(&ld->ld_mutex);
+	}
+
+	return rc;
+#undef QIN
+}
+
+static int lov_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 lov_io     *lio      = cl2lov_io(env, ios);
+	struct cl_page    *sub_page = lov_sub_page(slice);
+	struct lov_io_sub *sub;
+	int result;
+
+	sub = lov_page_subio(env, lio, slice);
+	if (!IS_ERR(sub)) {
+		result = cl_io_prepare_write(sub->sub_env, sub->sub_io,
+					     sub_page, from, to);
+		lov_sub_put(sub);
+	} else
+		result = PTR_ERR(sub);
+	return result;
+}
+
+static int lov_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 lov_io     *lio      = cl2lov_io(env, ios);
+	struct cl_page    *sub_page = lov_sub_page(slice);
+	struct lov_io_sub *sub;
+	int result;
+
+	sub = lov_page_subio(env, lio, slice);
+	if (!IS_ERR(sub)) {
+		result = cl_io_commit_write(sub->sub_env, sub->sub_io,
+					    sub_page, from, to);
+		lov_sub_put(sub);
+	} else
+		result = PTR_ERR(sub);
+	return result;
+}
+
+static int lov_io_fault_start(const struct lu_env *env,
+			      const struct cl_io_slice *ios)
+{
+	struct cl_fault_io *fio;
+	struct lov_io      *lio;
+	struct lov_io_sub  *sub;
+
+	fio = &ios->cis_io->u.ci_fault;
+	lio = cl2lov_io(env, ios);
+	sub = lov_sub_get(env, lio, lov_page_stripe(fio->ft_page));
+	sub->sub_io->u.ci_fault.ft_nob = fio->ft_nob;
+	lov_sub_put(sub);
+	return lov_io_start(env, ios);
+}
+
+static void lov_io_fsync_end(const struct lu_env *env,
+			     const struct cl_io_slice *ios)
+{
+	struct lov_io *lio = cl2lov_io(env, ios);
+	struct lov_io_sub *sub;
+	unsigned int *written = &ios->cis_io->u.ci_fsync.fi_nr_written;
+
+	*written = 0;
+	list_for_each_entry(sub, &lio->lis_active, sub_linkage) {
+		struct cl_io *subio = sub->sub_io;
+
+		lov_sub_enter(sub);
+		lov_io_end_wrapper(sub->sub_env, subio);
+		lov_sub_exit(sub);
+
+		if (subio->ci_result == 0)
+			*written += subio->u.ci_fsync.fi_nr_written;
+	}
+}
+
+static const struct cl_io_operations lov_io_ops = {
+	.op = {
+		[CIT_READ] = {
+			.cio_fini      = lov_io_fini,
+			.cio_iter_init = lov_io_rw_iter_init,
+			.cio_iter_fini = lov_io_iter_fini,
+			.cio_lock      = lov_io_lock,
+			.cio_unlock    = lov_io_unlock,
+			.cio_start     = lov_io_start,
+			.cio_end       = lov_io_end
+		},
+		[CIT_WRITE] = {
+			.cio_fini      = lov_io_fini,
+			.cio_iter_init = lov_io_rw_iter_init,
+			.cio_iter_fini = lov_io_iter_fini,
+			.cio_lock      = lov_io_lock,
+			.cio_unlock    = lov_io_unlock,
+			.cio_start     = lov_io_start,
+			.cio_end       = lov_io_end
+		},
+		[CIT_SETATTR] = {
+			.cio_fini      = lov_io_fini,
+			.cio_iter_init = lov_io_iter_init,
+			.cio_iter_fini = lov_io_iter_fini,
+			.cio_lock      = lov_io_lock,
+			.cio_unlock    = lov_io_unlock,
+			.cio_start     = lov_io_start,
+			.cio_end       = lov_io_end
+		},
+		[CIT_FAULT] = {
+			.cio_fini      = lov_io_fini,
+			.cio_iter_init = lov_io_iter_init,
+			.cio_iter_fini = lov_io_iter_fini,
+			.cio_lock      = lov_io_lock,
+			.cio_unlock    = lov_io_unlock,
+			.cio_start     = lov_io_fault_start,
+			.cio_end       = lov_io_end
+		},
+		[CIT_FSYNC] = {
+			.cio_fini      = lov_io_fini,
+			.cio_iter_init = lov_io_iter_init,
+			.cio_iter_fini = lov_io_iter_fini,
+			.cio_lock      = lov_io_lock,
+			.cio_unlock    = lov_io_unlock,
+			.cio_start     = lov_io_start,
+			.cio_end       = lov_io_fsync_end
+		},
+		[CIT_MISC] = {
+			.cio_fini   = lov_io_fini
+		}
+	},
+	.req_op = {
+		 [CRT_READ] = {
+			 .cio_submit    = lov_io_submit
+		 },
+		 [CRT_WRITE] = {
+			 .cio_submit    = lov_io_submit
+		 }
+	 },
+	.cio_prepare_write = lov_io_prepare_write,
+	.cio_commit_write  = lov_io_commit_write
+};
+
+/*****************************************************************************
+ *
+ * Empty lov io operations.
+ *
+ */
+
+static void lov_empty_io_fini(const struct lu_env *env,
+			      const struct cl_io_slice *ios)
+{
+	struct lov_object *lov = cl2lov(ios->cis_obj);
+
+	if (atomic_dec_and_test(&lov->lo_active_ios))
+		wake_up_all(&lov->lo_waitq);
+}
+
+static void lov_empty_impossible(const struct lu_env *env,
+				 struct cl_io_slice *ios)
+{
+	LBUG();
+}
+
+#define LOV_EMPTY_IMPOSSIBLE ((void *)lov_empty_impossible)
+
+/**
+ * An io operation vector for files without stripes.
+ */
+static const struct cl_io_operations lov_empty_io_ops = {
+	.op = {
+		[CIT_READ] = {
+			.cio_fini       = lov_empty_io_fini,
+#if 0
+			.cio_iter_init  = LOV_EMPTY_IMPOSSIBLE,
+			.cio_lock       = LOV_EMPTY_IMPOSSIBLE,
+			.cio_start      = LOV_EMPTY_IMPOSSIBLE,
+			.cio_end	= LOV_EMPTY_IMPOSSIBLE
+#endif
+		},
+		[CIT_WRITE] = {
+			.cio_fini      = lov_empty_io_fini,
+			.cio_iter_init = LOV_EMPTY_IMPOSSIBLE,
+			.cio_lock      = LOV_EMPTY_IMPOSSIBLE,
+			.cio_start     = LOV_EMPTY_IMPOSSIBLE,
+			.cio_end       = LOV_EMPTY_IMPOSSIBLE
+		},
+		[CIT_SETATTR] = {
+			.cio_fini      = lov_empty_io_fini,
+			.cio_iter_init = LOV_EMPTY_IMPOSSIBLE,
+			.cio_lock      = LOV_EMPTY_IMPOSSIBLE,
+			.cio_start     = LOV_EMPTY_IMPOSSIBLE,
+			.cio_end       = LOV_EMPTY_IMPOSSIBLE
+		},
+		[CIT_FAULT] = {
+			.cio_fini      = lov_empty_io_fini,
+			.cio_iter_init = LOV_EMPTY_IMPOSSIBLE,
+			.cio_lock      = LOV_EMPTY_IMPOSSIBLE,
+			.cio_start     = LOV_EMPTY_IMPOSSIBLE,
+			.cio_end       = LOV_EMPTY_IMPOSSIBLE
+		},
+		[CIT_FSYNC] = {
+			.cio_fini   = lov_empty_io_fini
+		},
+		[CIT_MISC] = {
+			.cio_fini   = lov_empty_io_fini
+		}
+	},
+	.req_op = {
+		 [CRT_READ] = {
+			 .cio_submit    = LOV_EMPTY_IMPOSSIBLE
+		 },
+		 [CRT_WRITE] = {
+			 .cio_submit    = LOV_EMPTY_IMPOSSIBLE
+		 }
+	 },
+	.cio_commit_write = LOV_EMPTY_IMPOSSIBLE
+};
+
+int lov_io_init_raid0(const struct lu_env *env, struct cl_object *obj,
+		      struct cl_io *io)
+{
+	struct lov_io       *lio = lov_env_io(env);
+	struct lov_object   *lov = cl2lov(obj);
+
+	INIT_LIST_HEAD(&lio->lis_active);
+	lov_io_slice_init(lio, lov, io);
+	if (io->ci_result == 0) {
+		io->ci_result = lov_io_subio_init(env, lio, io);
+		if (io->ci_result == 0) {
+			cl_io_slice_add(io, &lio->lis_cl, obj, &lov_io_ops);
+			atomic_inc(&lov->lo_active_ios);
+		}
+	}
+	return io->ci_result;
+}
+
+int lov_io_init_empty(const struct lu_env *env, struct cl_object *obj,
+		      struct cl_io *io)
+{
+	struct lov_object *lov = cl2lov(obj);
+	struct lov_io *lio = lov_env_io(env);
+	int result;
+
+	lio->lis_object = lov;
+	switch (io->ci_type) {
+	default:
+		LBUG();
+	case CIT_MISC:
+	case CIT_READ:
+		result = 0;
+		break;
+	case CIT_FSYNC:
+	case CIT_SETATTR:
+		result = 1;
+		break;
+	case CIT_WRITE:
+		result = -EBADF;
+		break;
+	case CIT_FAULT:
+		result = -EFAULT;
+		CERROR("Page fault on a file without stripes: "DFID"\n",
+		       PFID(lu_object_fid(&obj->co_lu)));
+		break;
+	}
+	if (result == 0) {
+		cl_io_slice_add(io, &lio->lis_cl, obj, &lov_empty_io_ops);
+		atomic_inc(&lov->lo_active_ios);
+	}
+
+	io->ci_result = result < 0 ? result : 0;
+	return result != 0;
+}
+
+int lov_io_init_released(const struct lu_env *env, struct cl_object *obj,
+			struct cl_io *io)
+{
+	struct lov_object *lov = cl2lov(obj);
+	struct lov_io *lio = lov_env_io(env);
+	int result;
+
+	LASSERT(lov->lo_lsm != NULL);
+	lio->lis_object = lov;
+
+	switch (io->ci_type) {
+	default:
+		LASSERTF(0, "invalid type %d\n", io->ci_type);
+	case CIT_MISC:
+	case CIT_FSYNC:
+		result = 1;
+		break;
+	case CIT_SETATTR:
+		/* the truncate to 0 is managed by MDT:
+		 * - in open, for open O_TRUNC
+		 * - in setattr, for truncate
+		 */
+		/* the truncate is for size > 0 so triggers a restore */
+		if (cl_io_is_trunc(io))
+			io->ci_restore_needed = 1;
+		result = -ENODATA;
+		break;
+	case CIT_READ:
+	case CIT_WRITE:
+	case CIT_FAULT:
+		io->ci_restore_needed = 1;
+		result = -ENODATA;
+		break;
+	}
+	if (result == 0) {
+		cl_io_slice_add(io, &lio->lis_cl, obj, &lov_empty_io_ops);
+		atomic_inc(&lov->lo_active_ios);
+	}
+
+	io->ci_result = result < 0 ? result : 0;
+	return result != 0;
+}
+/** @} lov */