X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Flov%2Flov_io.c;h=7ac4590ff9226c6d5aaff75eb71726f7c032d3a6;hp=b21fd941a77803200cce30d6fcc624cfc09075e3;hb=893e5a99e766ab97e95217b7b201b9d293bed6e0;hpb=0b72da3f303132ec09d80c65156c7a20fa03c721

diff --git a/lustre/lov/lov_io.c b/lustre/lov/lov_io.c
index b21fd94..7ac4590f 100644
--- a/lustre/lov/lov_io.c
+++ b/lustre/lov/lov_io.c
@@ -1,6 +1,4 @@
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
+/*
  * GPL HEADER START
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
@@ -17,17 +15,15 @@
  *
  * 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.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -36,6 +32,7 @@
  * 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
@@ -46,194 +43,145 @@
  *  @{
  */
 
-static void lov_sub_enter(struct lov_io_sub *sub)
+static inline struct lov_io_sub *lov_sub_alloc(struct lov_io *lio, int index)
 {
-        ENTRY;
-        if (sub->sub_reenter++ == 0) {
-                sub->sub_cookie = cl_env_reenter();
-                cl_env_implant(sub->sub_env, &sub->sub_refcheck2);
-        }
-        EXIT;
+	struct lov_io_sub *sub;
+
+	if (lio->lis_nr_subios == 0) {
+		LASSERT(lio->lis_single_subio_index == -1);
+		sub = &lio->lis_single_subio;
+		lio->lis_single_subio_index = index;
+		memset(sub, 0, sizeof(*sub));
+	} else {
+		OBD_ALLOC_PTR(sub);
+	}
+
+	if (sub != NULL) {
+		INIT_LIST_HEAD(&sub->sub_list);
+		INIT_LIST_HEAD(&sub->sub_linkage);
+		sub->sub_subio_index = index;
+	}
+
+	return sub;
 }
 
-static void lov_sub_exit(struct lov_io_sub *sub)
+static inline void lov_sub_free(struct lov_io *lio, struct lov_io_sub *sub)
 {
-        ENTRY;
-        if (--sub->sub_reenter == 0) {
-                cl_env_unplant(sub->sub_env, &sub->sub_refcheck2);
-                cl_env_reexit(sub->sub_cookie);
-        }
-        EXIT;
+	if (sub->sub_subio_index == lio->lis_single_subio_index) {
+		LASSERT(sub == &lio->lis_single_subio);
+		lio->lis_single_subio_index = -1;
+	} else {
+		OBD_FREE_PTR(sub);
+	}
 }
 
 static void lov_io_sub_fini(const struct lu_env *env, struct lov_io *lio,
-                            struct lov_io_sub *sub)
-{
-        ENTRY;
-        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;
-        }
-        EXIT;
-}
-
-static void lov_io_sub_inherit(struct cl_io *io, struct lov_io *lio,
-                               int stripe, loff_t start, loff_t end)
+			    struct lov_io_sub *sub)
 {
-        struct lov_stripe_md *lsm    = lov_r0(lio->lis_object)->lo_lsm;
-        struct cl_io         *parent = lio->lis_cl.cis_io;
+	ENTRY;
 
-        switch(io->ci_type) {
-        case CIT_TRUNC: {
-                loff_t new_size = parent->u.ci_truncate.tr_size;
+	cl_io_fini(sub->sub_env, &sub->sub_io);
 
-                new_size = lov_size_to_stripe(lsm, new_size, stripe);
-                io->u.ci_truncate.tr_capa = parent->u.ci_truncate.tr_capa;
-                io->u.ci_truncate.tr_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_READ:
-        case CIT_WRITE: {
-                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;
-        }
+	if (sub->sub_env != NULL && !IS_ERR(sub->sub_env)) {
+		cl_env_put(sub->sub_env, &sub->sub_refcheck);
+		sub->sub_env = NULL;
+	}
+	EXIT;
 }
 
-static int lov_io_sub_init(const struct lu_env *env, struct lov_io *lio,
-                           struct lov_io_sub *sub)
+static inline bool
+is_index_within_mirror(struct lov_object *lov, int index, int mirror_index)
 {
-        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);
-        ENTRY;
-
-        result = 0;
-        sub->sub_io_initialized = 0;
-        sub->sub_borrowed = 0;
-
-        if (lio->lis_mem_frozen) {
-                LASSERT(cfs_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;
-                        }
-                }
-        }
+	struct lov_layout_composite *comp = &lov->u.composite;
+	struct lov_mirror_entry *lre = &comp->lo_mirrors[mirror_index];
 
-        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;
-
-                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);
+	return (index >= lre->lre_start && index <= lre->lre_end);
 }
 
-struct lov_io_sub *lov_sub_get(const struct lu_env *env,
-                               struct lov_io *lio, int stripe)
+static int lov_io_sub_init(const struct lu_env *env, struct lov_io *lio,
+			   struct lov_io_sub *sub)
 {
-        int rc;
-        struct lov_io_sub *sub = &lio->lis_subs[stripe];
-
-        LASSERT(stripe < lio->lis_stripe_count);
-        ENTRY;
-
-        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);
+	struct lov_object *lov = lio->lis_object;
+	struct cl_io *sub_io;
+	struct cl_object *sub_obj;
+	struct cl_io *io = lio->lis_cl.cis_io;
+	int index = lov_comp_entry(sub->sub_subio_index);
+	int stripe = lov_comp_stripe(sub->sub_subio_index);
+	int result = 0;
+	LASSERT(sub->sub_env == NULL);
+	ENTRY;
+
+	if (unlikely(!lov_r0(lov, index)->lo_sub ||
+		     !lov_r0(lov, index)->lo_sub[stripe]))
+		RETURN(-EIO);
+
+	LASSERTF(is_index_within_mirror(lov, index, lio->lis_mirror_index),
+		 DFID "iot = %d, index = %d, mirror = %d\n",
+		 PFID(lu_object_fid(lov2lu(lov))), io->ci_type, index,
+		 lio->lis_mirror_index);
+
+	/* obtain new environment */
+	sub->sub_env = cl_env_get(&sub->sub_refcheck);
+	if (IS_ERR(sub->sub_env))
+		result = PTR_ERR(sub->sub_env);
+
+	sub_obj = lovsub2cl(lov_r0(lov, index)->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;
+	sub_io->ci_pio = io->ci_pio;
+	sub_io->ci_lock_no_expand = io->ci_lock_no_expand;
+	sub_io->ci_ndelay = io->ci_ndelay;
+	sub_io->ci_layout_version = io->ci_layout_version;
+
+	result = cl_io_sub_init(sub->sub_env, sub_io, io->ci_type, sub_obj);
+
+	if (result < 0)
+		lov_io_sub_fini(env, lio, sub);
+
+	RETURN(result);
 }
 
-void lov_sub_put(struct lov_io_sub *sub)
+struct lov_io_sub *lov_sub_get(const struct lu_env *env,
+			       struct lov_io *lio, int index)
 {
-        lov_sub_exit(sub);
+	struct lov_io_sub *sub;
+	int rc = 0;
+
+	ENTRY;
+
+	list_for_each_entry(sub, &lio->lis_subios, sub_list) {
+		if (sub->sub_subio_index == index) {
+			rc = 1;
+			break;
+		}
+	}
+
+	if (rc == 0) {
+		sub = lov_sub_alloc(lio, index);
+		if (sub == NULL)
+			GOTO(out, rc = -ENOMEM);
+
+		rc = lov_io_sub_init(env, lio, sub);
+		if (rc < 0) {
+			lov_sub_free(lio, sub);
+			GOTO(out, rc);
+		}
+
+		list_add_tail(&sub->sub_list, &lio->lis_subios);
+		lio->lis_nr_subios++;
+	}
+out:
+	if (rc < 0)
+		sub = ERR_PTR(rc);
+	RETURN(sub);
 }
 
 /*****************************************************************************
@@ -242,92 +190,317 @@ void lov_sub_put(struct lov_io_sub *sub)
  *
  */
 
-static int lov_page_stripe(const struct cl_page *page)
+int lov_page_index(const struct cl_page *page)
 {
-        struct lovsub_object *subobj;
+	const struct cl_page_slice *slice;
+	ENTRY;
 
-        ENTRY;
-        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  = lov_r0(lio->lis_object)->lo_lsm;
-        struct cl_page       *page = slice->cpl_page;
-        int stripe;
+	slice = cl_page_at(page, &lov_device_type);
+	LASSERT(slice != NULL);
+	LASSERT(slice->cpl_obj != NULL);
 
-        LASSERT(lio->lis_cl.cis_io != NULL);
-        LASSERT(cl2lov(slice->cpl_obj) == lio->lis_object);
-        LASSERT(lsm != NULL);
-        LASSERT(lio->lis_nr_subios > 0);
-        ENTRY;
-
-        stripe = lov_page_stripe(page);
-        RETURN(lov_sub_get(env, lio, stripe));
+	RETURN(cl2lov_page(slice)->lps_index);
 }
 
-
 static int lov_io_subio_init(const struct lu_env *env, struct lov_io *lio,
                              struct cl_io *io)
 {
-        struct lov_object    *lov = lio->lis_object;
-        struct lov_stripe_md *lsm = lov_r0(lov)->lo_lsm;
-        int result;
+	ENTRY;
 
-        LASSERT(lio->lis_object != NULL);
-        ENTRY;
+	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(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);
+	INIT_LIST_HEAD(&lio->lis_subios);
+	lio->lis_single_subio_index = -1;
+	lio->lis_nr_subios = 0;
+
+	RETURN(0);
 }
 
-static void lov_io_slice_init(struct lov_io *lio,
-                              struct lov_object *obj, struct cl_io *io)
+/**
+ * Decide if it will need write intent RPC
+ */
+static int lov_io_mirror_write_intent(struct lov_io *lio,
+	struct lov_object *obj, struct cl_io *io)
 {
-        struct lov_stripe_md *lsm = lov_r0(obj)->lo_lsm;
+	struct lov_layout_composite *comp = &obj->u.composite;
+	struct lu_extent *ext = &io->ci_write_intent;
+	struct lov_mirror_entry *lre;
+	struct lov_mirror_entry *primary;
+	struct lov_layout_entry *lle;
+	size_t count = 0;
+	ENTRY;
+
+	*ext = (typeof(*ext)) { lio->lis_pos, lio->lis_endpos };
+	io->ci_need_write_intent = 0;
+
+	if (!(io->ci_type == CIT_WRITE || cl_io_is_trunc(io) ||
+	      cl_io_is_mkwrite(io)))
+		RETURN(0);
+
+	/* FLR: check if it needs to send a write intent RPC to server.
+	 * Writing to sync_pending file needs write intent RPC to change
+	 * the file state back to write_pending, so that the layout version
+	 * can be increased when the state changes to sync_pending at a later
+	 * time. Otherwise there exists a chance that an evicted client may
+	 * dirty the file data while resync client is working on it.
+	 * Designated I/O is allowed for resync workload.
+	 */
+	if (lov_flr_state(obj) == LCM_FL_RDONLY ||
+	    (lov_flr_state(obj) == LCM_FL_SYNC_PENDING &&
+	     io->ci_designated_mirror == 0)) {
+		io->ci_need_write_intent = 1;
+		RETURN(0);
+	}
+
+	LASSERT((lov_flr_state(obj) == LCM_FL_WRITE_PENDING));
+	LASSERT(comp->lo_preferred_mirror >= 0);
+
+	/* need to iterate all components to see if there are
+	 * multiple components covering the writing component */
+	primary = &comp->lo_mirrors[comp->lo_preferred_mirror];
+	LASSERT(!primary->lre_stale);
+	lov_foreach_mirror_layout_entry(obj, lle, primary) {
+		LASSERT(lle->lle_valid);
+		if (!lu_extent_is_overlapped(ext, lle->lle_extent))
+			continue;
+
+		ext->e_start = MIN(ext->e_start, lle->lle_extent->e_start);
+		ext->e_end = MAX(ext->e_end, lle->lle_extent->e_end);
+		++count;
+	}
+	if (count == 0) {
+		CERROR(DFID ": cannot find any valid components covering "
+		       "file extent "DEXT", mirror: %d\n",
+		       PFID(lu_object_fid(lov2lu(obj))), PEXT(ext),
+		       primary->lre_mirror_id);
+		RETURN(-EIO);
+	}
+
+	count = 0;
+	lov_foreach_mirror_entry(obj, lre) {
+		if (lre == primary)
+			continue;
+
+		lov_foreach_mirror_layout_entry(obj, lle, lre) {
+			if (!lle->lle_valid)
+				continue;
+
+			if (lu_extent_is_overlapped(ext, lle->lle_extent)) {
+				++count;
+				break;
+			}
+		}
+	}
+
+	CDEBUG(D_VFSTRACE, DFID "there are %zd components to be staled to "
+	       "modify file extent "DEXT", iot: %d\n",
+	       PFID(lu_object_fid(lov2lu(obj))), count, PEXT(ext), io->ci_type);
+
+	io->ci_need_write_intent = count > 0;
+
+	RETURN(0);
+}
 
-        LASSERT(lsm != NULL);
-        ENTRY;
+static int lov_io_mirror_init(struct lov_io *lio, struct lov_object *obj,
+			       struct cl_io *io)
+{
+	struct lov_layout_composite *comp = &obj->u.composite;
+	int index;
+	int i;
+	int result;
+	ENTRY;
+
+	if (!lov_is_flr(obj)) {
+		LASSERT(comp->lo_preferred_mirror == 0);
+		lio->lis_mirror_index = comp->lo_preferred_mirror;
+		io->ci_ndelay = 0;
+		RETURN(0);
+	}
+
+	/* transfer the layout version for verification */
+	if (io->ci_layout_version == 0)
+		io->ci_layout_version = obj->lo_lsm->lsm_layout_gen;
+
+	/* find the corresponding mirror for designated mirror IO */
+	if (io->ci_designated_mirror > 0) {
+		struct lov_mirror_entry *entry;
+
+		LASSERT(!io->ci_ndelay);
+
+		CDEBUG(D_LAYOUT, "designated I/O mirror state: %d\n",
+		      lov_flr_state(obj));
+
+		if ((cl_io_is_trunc(io) || io->ci_type == CIT_WRITE) &&
+		    (io->ci_layout_version != obj->lo_lsm->lsm_layout_gen)) {
+			/* For resync I/O, the ci_layout_version was the layout
+			 * version when resync starts. If it doesn't match the
+			 * current object layout version, it means the layout
+			 * has been changed */
+			RETURN(-ESTALE);
+		}
+
+		io->ci_layout_version |= LU_LAYOUT_RESYNC;
+
+		index = 0;
+		lio->lis_mirror_index = -1;
+		lov_foreach_mirror_entry(obj, entry) {
+			if (entry->lre_mirror_id ==
+			    io->ci_designated_mirror) {
+				lio->lis_mirror_index = index;
+				break;
+			}
+
+			index++;
+		}
+
+		RETURN(lio->lis_mirror_index < 0 ? -EINVAL : 0);
+	}
+
+	result = lov_io_mirror_write_intent(lio, obj, io);
+	if (result)
+		RETURN(result);
+
+	if (io->ci_need_write_intent) {
+		CDEBUG(D_VFSTRACE, DFID " need write intent for [%llu, %llu)\n",
+		       PFID(lu_object_fid(lov2lu(obj))),
+		       lio->lis_pos, lio->lis_endpos);
+
+		if (cl_io_is_trunc(io)) {
+			/**
+			 * for truncate, we uses [size, EOF) to judge whether
+			 * a write intent needs to be send, but we need to
+			 * restore the write extent to [0, size).
+			 */
+			io->ci_write_intent.e_start = 0;
+			io->ci_write_intent.e_end =
+					io->u.ci_setattr.sa_attr.lvb_size;
+		}
+		/* stop cl_io_init() loop */
+		RETURN(1);
+	}
+
+	if (io->ci_ndelay_tried == 0 || /* first time to try */
+	    /* reset the mirror index if layout has changed */
+	    lio->lis_mirror_layout_gen != obj->lo_lsm->lsm_layout_gen) {
+		lio->lis_mirror_layout_gen = obj->lo_lsm->lsm_layout_gen;
+		index = lio->lis_mirror_index = comp->lo_preferred_mirror;
+	} else {
+		index = lio->lis_mirror_index;
+		LASSERT(index >= 0);
+
+		/* move mirror index to the next one */
+		index = (index + 1) % comp->lo_mirror_count;
+	}
+
+	for (i = 0; i < comp->lo_mirror_count; i++) {
+		struct lu_extent ext = { .e_start = lio->lis_pos,
+					 .e_end   = lio->lis_pos + 1 };
+		struct lov_mirror_entry *lre;
+		struct lov_layout_entry *lle;
+		bool found = false;
+
+		lre = &comp->lo_mirrors[(index + i) % comp->lo_mirror_count];
+		if (!lre->lre_valid)
+			continue;
+
+		lov_foreach_mirror_layout_entry(obj, lle, lre) {
+			if (!lle->lle_valid)
+				continue;
+
+			if (lu_extent_is_overlapped(&ext, lle->lle_extent)) {
+				found = true;
+				break;
+			}
+		}
+
+		if (found) {
+			index = (index + i) % comp->lo_mirror_count;
+			break;
+		}
+	}
+	if (i == comp->lo_mirror_count) {
+		CERROR(DFID": failed to find a component covering "
+		       "I/O region at %llu\n",
+		       PFID(lu_object_fid(lov2lu(obj))), lio->lis_pos);
+
+		dump_lsm(D_ERROR, obj->lo_lsm);
+
+		RETURN(-EIO);
+	}
+
+	CDEBUG(D_VFSTRACE, DFID ": flr state: %d, move mirror from %d to %d, "
+	       "have retried: %d, mirror count: %d\n",
+	       PFID(lu_object_fid(lov2lu(obj))), lov_flr_state(obj),
+	       lio->lis_mirror_index, index, io->ci_ndelay_tried,
+	       comp->lo_mirror_count);
+
+	lio->lis_mirror_index = index;
+
+	/* FLR: if all mirrors have been tried once, most likely the network
+	 * of this client has been partitioned. We should relinquish CPU for
+	 * a while before trying again. */
+	++io->ci_ndelay_tried;
+	if (io->ci_ndelay && io->ci_ndelay_tried >= comp->lo_mirror_count) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule_timeout(msecs_to_jiffies(MSEC_PER_SEC)); /* 10ms */
+		if (signal_pending(current))
+			RETURN(-EINTR);
+
+		/* reset retry counter */
+		io->ci_ndelay_tried = 1;
+	}
+
+	CDEBUG(D_VFSTRACE, "use %sdelayed RPC state for this IO\n",
+	       io->ci_ndelay ? "non-" : "");
+
+	RETURN(0);
+}
 
-        io->ci_result = 0;
-        lio->lis_object = obj;
-        lio->lis_stripe_count = 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);
+static int lov_io_slice_init(struct lov_io *lio,
+			     struct lov_object *obj, struct cl_io *io)
+{
+	int index;
+	int result = 0;
+	ENTRY;
+
+	io->ci_result = 0;
+	lio->lis_object = obj;
+
+	LASSERT(obj->lo_lsm != NULL);
+
+	switch (io->ci_type) {
+	case CIT_READ:
+	case CIT_WRITE:
+		lio->lis_pos = io->u.ci_rw.rw_range.cir_pos;
+		lio->lis_endpos = lio->lis_pos + io->u.ci_rw.rw_range.cir_count;
+		lio->lis_io_endpos = lio->lis_endpos;
+		if (cl_io_is_append(io)) {
+			LASSERT(io->ci_type == CIT_WRITE);
+
+			/* If there is LOV EA hole, then we may cannot locate
+			 * the current file-tail exactly. */
+			if (unlikely(obj->lo_lsm->lsm_entries[0]->lsme_pattern &
+				     LOV_PATTERN_F_HOLE))
+				GOTO(out, result = -EIO);
+
+			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_TRUNC:
-                lio->lis_pos = io->u.ci_truncate.tr_size;
                 lio->lis_endpos = OBD_OBJECT_EOF;
                 break;
 
+	case CIT_DATA_VERSION:
+		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);
@@ -335,6 +508,28 @@ static void lov_io_slice_init(struct lov_io *lio,
                 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_LADVISE: {
+		lio->lis_pos = io->u.ci_ladvise.li_start;
+		lio->lis_endpos = io->u.ci_ladvise.li_end;
+		break;
+	}
+
+	case CIT_GLIMPSE:
+		lio->lis_pos = 0;
+		lio->lis_endpos = OBD_OBJECT_EOF;
+
+		if (lov_flr_state(obj) == LCM_FL_RDONLY &&
+		    !OBD_FAIL_CHECK(OBD_FAIL_FLR_GLIMPSE_IMMUTABLE))
+			/* SoM is accurate, no need glimpse */
+			GOTO(out, result = 1);
+		break;
+
         case CIT_MISC:
                 lio->lis_pos = 0;
                 lio->lis_endpos = OBD_OBJECT_EOF;
@@ -344,26 +539,166 @@ static void lov_io_slice_init(struct lov_io *lio,
                 LBUG();
         }
 
-        EXIT;
+	result = lov_io_mirror_init(lio, obj, io);
+	if (result)
+		GOTO(out, result);
+
+	/* check if it needs to instantiate layout */
+	if (!(io->ci_type == CIT_WRITE || cl_io_is_mkwrite(io) ||
+	      (cl_io_is_trunc(io) && io->u.ci_setattr.sa_attr.lvb_size > 0)))
+		GOTO(out, result = 0);
+
+	/* for truncate, it only needs to instantiate the components
+	 * before the truncated size. */
+	if (cl_io_is_trunc(io)) {
+		io->ci_write_intent.e_start = 0;
+		io->ci_write_intent.e_end = io->u.ci_setattr.sa_attr.lvb_size;
+	} else {
+		io->ci_write_intent.e_start = lio->lis_pos;
+		io->ci_write_intent.e_end = lio->lis_endpos;
+	}
+
+	index = 0;
+	lov_foreach_io_layout(index, lio, &io->ci_write_intent) {
+		if (!lsm_entry_inited(obj->lo_lsm, index)) {
+			io->ci_need_write_intent = 1;
+			break;
+		}
+	}
+
+	if (io->ci_need_write_intent && io->ci_designated_mirror > 0) {
+		/* REINT_SYNC RPC has already tried to instantiate all of the
+		 * components involved, obviously it didn't succeed. Skip this
+		 * mirror for now. The server won't be able to figure out
+		 * which mirror it should instantiate components */
+		CERROR(DFID": trying to instantiate components for designated "
+		       "I/O, file state: %d\n",
+		       PFID(lu_object_fid(lov2lu(obj))), lov_flr_state(obj));
+
+		io->ci_need_write_intent = 0;
+		GOTO(out, result = -EIO);
+	}
+
+	if (io->ci_need_write_intent)
+		GOTO(out, result = 1);
+
+	EXIT;
+
+out:
+	return result;
 }
 
 static void lov_io_fini(const struct lu_env *env, const struct cl_io_slice *ios)
 {
-        struct lov_io *lio = cl2lov_io(env, ios);
-        int i;
+	struct lov_io *lio = cl2lov_io(env, ios);
+	struct lov_object *lov = cl2lov(ios->cis_obj);
 
-        ENTRY;
-        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(lio->lis_subs,
-                         lio->lis_nr_subios * sizeof lio->lis_subs[0]);
-                lio->lis_nr_subios = 0;
-        }
-        EXIT;
+	ENTRY;
+
+	LASSERT(list_empty(&lio->lis_active));
+
+	while (!list_empty(&lio->lis_subios)) {
+		struct lov_io_sub *sub = list_entry(lio->lis_subios.next,
+						    struct lov_io_sub,
+						    sub_list);
+
+		list_del_init(&sub->sub_list);
+		lio->lis_nr_subios--;
+
+		lov_io_sub_fini(env, lio, sub);
+		lov_sub_free(lio, sub);
+	}
+	LASSERT(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);
+	EXIT;
+}
+
+static void lov_io_sub_inherit(struct lov_io_sub *sub, struct lov_io *lio,
+			       loff_t start, loff_t end)
+{
+	struct cl_io *io = &sub->sub_io;
+	struct lov_stripe_md *lsm = lio->lis_object->lo_lsm;
+	struct cl_io *parent = lio->lis_cl.cis_io;
+	int index = lov_comp_entry(sub->sub_subio_index);
+	int stripe = lov_comp_stripe(sub->sub_subio_index);
+
+	io->ci_pio = parent->ci_pio;
+	switch (io->ci_type) {
+	case CIT_SETATTR: {
+		io->u.ci_setattr.sa_attr = parent->u.ci_setattr.sa_attr;
+		io->u.ci_setattr.sa_attr_flags =
+			parent->u.ci_setattr.sa_attr_flags;
+		io->u.ci_setattr.sa_valid = parent->u.ci_setattr.sa_valid;
+		io->u.ci_setattr.sa_stripe_index = stripe;
+		io->u.ci_setattr.sa_parent_fid =
+					parent->u.ci_setattr.sa_parent_fid;
+		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, index, new_size,
+						      stripe);
+			io->u.ci_setattr.sa_attr.lvb_size = new_size;
+		}
+		lov_lsm2layout(lsm, lsm->lsm_entries[index],
+			       &io->u.ci_setattr.sa_layout);
+		break;
+	}
+	case CIT_DATA_VERSION: {
+		io->u.ci_data_version.dv_data_version = 0;
+		io->u.ci_data_version.dv_flags =
+			parent->u.ci_data_version.dv_flags;
+		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, index, 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_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_rw.rw_ptask = parent->u.ci_rw.rw_ptask;
+		io->u.ci_rw.rw_iter = parent->u.ci_rw.rw_iter;
+		io->u.ci_rw.rw_iocb = parent->u.ci_rw.rw_iocb;
+		io->u.ci_rw.rw_file = parent->u.ci_rw.rw_file;
+		io->u.ci_rw.rw_sync = parent->u.ci_rw.rw_sync;
+		if (cl_io_is_append(parent)) {
+			io->u.ci_rw.rw_append = 1;
+		} else {
+			io->u.ci_rw.rw_range.cir_pos = start;
+			io->u.ci_rw.rw_range.cir_count = end - start;
+		}
+		break;
+	}
+	case CIT_LADVISE: {
+		io->u.ci_ladvise.li_start = start;
+		io->u.ci_ladvise.li_end = end;
+		io->u.ci_ladvise.li_fid = parent->u.ci_ladvise.li_fid;
+		io->u.ci_ladvise.li_advice = parent->u.ci_ladvise.li_advice;
+		io->u.ci_ladvise.li_flags = parent->u.ci_ladvise.li_flags;
+		break;
+	}
+	case CIT_GLIMPSE:
+	case CIT_MISC:
+	default:
+		break;
+	}
 }
 
-static obd_off lov_offset_mod(obd_off val, int delta)
+static loff_t lov_offset_mod(loff_t val, int delta)
 {
         if (val != OBD_OBJECT_EOF)
                 val += delta;
@@ -371,96 +706,195 @@ static obd_off lov_offset_mod(obd_off val, int delta)
 }
 
 static int lov_io_iter_init(const struct lu_env *env,
-                            const struct cl_io_slice *ios)
+			    const struct cl_io_slice *ios)
 {
-        struct lov_io        *lio = cl2lov_io(env, ios);
-        struct lov_stripe_md *lsm = lov_r0(lio->lis_object)->lo_lsm;
-        struct lov_io_sub    *sub;
-        obd_off endpos;
-        obd_off start;
-        obd_off end;
-        int stripe;
-        int rc = 0;
+	struct lov_io        *lio = cl2lov_io(env, ios);
+	struct lov_stripe_md *lsm = lio->lis_object->lo_lsm;
+	struct lov_io_sub    *sub;
+	struct lu_extent ext;
+	int index;
+	int rc = 0;
 
         ENTRY;
-        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;
-
-                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: %i [%llu, %llu)\n",
-                               stripe, start, end);
-                } else
-                        rc = PTR_ERR(sub);
-
-                if (!rc)
-                        cfs_list_add_tail(&sub->sub_linkage, &lio->lis_active);
-                else
-                        break;
-        }
-        RETURN(rc);
+
+	ext.e_start = lio->lis_pos;
+	ext.e_end = lio->lis_endpos;
+
+	lov_foreach_io_layout(index, lio, &ext) {
+		struct lov_layout_entry *le = lov_entry(lio->lis_object, index);
+		struct lov_layout_raid0 *r0 = &le->lle_raid0;
+		u64 start;
+		u64 end;
+		int stripe;
+
+		CDEBUG(D_VFSTRACE, "component[%d] flags %#x\n",
+		       index, lsm->lsm_entries[index]->lsme_flags);
+		if (!lsm_entry_inited(lsm, index)) {
+			/* Read from uninitialized components should return
+			 * zero filled pages. */
+			continue;
+		}
+
+		if (!le->lle_valid && !ios->cis_io->ci_designated_mirror) {
+			CERROR("I/O to invalid component: %d, mirror: %d\n",
+			       index, lio->lis_mirror_index);
+			RETURN(-EIO);
+		}
+
+		for (stripe = 0; stripe < r0->lo_nr; stripe++) {
+			if (!lov_stripe_intersects(lsm, index, stripe,
+						   &ext, &start, &end))
+				continue;
+
+			if (unlikely(r0->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,
+					  lov_comp_index(index, stripe));
+			if (IS_ERR(sub)) {
+				rc = PTR_ERR(sub);
+				break;
+			}
+
+			lov_io_sub_inherit(sub, lio, start, end);
+			rc = cl_io_iter_init(sub->sub_env, &sub->sub_io);
+			if (rc != 0)
+				cl_io_iter_fini(sub->sub_env, &sub->sub_io);
+			if (rc != 0)
+				break;
+
+			CDEBUG(D_VFSTRACE,
+				"shrink stripe: {%d, %d} range: [%llu, %llu)\n",
+				index, stripe, start, end);
+
+			list_add_tail(&sub->sub_linkage, &lio->lis_active);
+		}
+		if (rc != 0)
+			break;
+	}
+	RETURN(rc);
 }
 
 static int lov_io_rw_iter_init(const struct lu_env *env,
-                               const struct cl_io_slice *ios)
+			       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 = lov_r0(cl2lov(ios->cis_obj))->lo_lsm;
-        loff_t 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);
-        ENTRY;
+	struct cl_io *io = ios->cis_io;
+	struct lov_io *lio = cl2lov_io(env, ios);
+	struct lov_stripe_md_entry *lse;
+	struct cl_io_range *range = &io->u.ci_rw.rw_range;
+	loff_t start = range->cir_pos;
+	loff_t next;
+	int index;
+
+	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
+	ENTRY;
+
+	if (cl_io_is_append(io))
+		RETURN(lov_io_iter_init(env, ios));
+
+	index = lov_io_layout_at(lio, range->cir_pos);
+	if (index < 0) { /* non-existing layout component */
+		if (io->ci_type == CIT_READ) {
+			/* TODO: it needs to detect the next component and
+			 * then set the next pos */
+			io->ci_continue = 0;
+			/* execute it in main thread */
+			io->ci_pio = 0;
+
+			RETURN(lov_io_iter_init(env, ios));
+		}
+
+		RETURN(-ENODATA);
+	}
+
+	if (!lov_entry(lio->lis_object, index)->lle_valid &&
+	    !io->ci_designated_mirror)
+		RETURN(io->ci_type == CIT_READ ? -EAGAIN : -EIO);
+
+	lse = lov_lse(lio->lis_object, index);
+
+	next = MAX_LFS_FILESIZE;
+	if (lse->lsme_stripe_count > 1) {
+		unsigned long ssize = lse->lsme_stripe_size;
+
+		lov_do_div64(start, ssize);
+		next = (start + 1) * ssize;
+		if (next <= start * ssize)
+			next = MAX_LFS_FILESIZE;
+	}
+
+	LASSERTF(range->cir_pos >= lse->lsme_extent.e_start,
+		 "pos %lld, [%lld, %lld)\n", range->cir_pos,
+		 lse->lsme_extent.e_start, lse->lsme_extent.e_end);
+	next = min_t(__u64, next, lse->lsme_extent.e_end);
+	next = min_t(loff_t, next, lio->lis_io_endpos);
+
+	io->ci_continue  = next < lio->lis_io_endpos;
+	range->cir_count = next - range->cir_pos;
+	lio->lis_pos     = range->cir_pos;
+	lio->lis_endpos  = range->cir_pos + range->cir_count;
+	CDEBUG(D_VFSTRACE,
+	       "stripe: {%d, %llu} range: [%llu, %llu) end: %llu, count: %zd\n",
+	       index, start, lio->lis_pos, lio->lis_endpos,
+	       lio->lis_io_endpos, range->cir_count);
+
+	if (!io->ci_continue) {
+		/* the last piece of IO, execute it in main thread */
+		io->ci_pio = 0;
+	}
+
+	if (io->ci_pio)
+		RETURN(0);
+
+	/*
+	 * 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));
+}
 
-        /* fast path for common case. */
-        if (lio->lis_nr_subios != 1 && !cl_io_is_append(io)) {
-
-                do_div(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_setattr_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;
+	int index;
+	ENTRY;
+
+	if (cl_io_is_trunc(io) && lio->lis_pos > 0) {
+		index = lov_io_layout_at(lio, lio->lis_pos - 1);
+		/* no entry found for such offset */
+		if (index < 0)
+			RETURN(io->ci_result = -ENODATA);
+	}
+
+	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 *))
+		       int (*iofunc)(const struct lu_env *, struct cl_io *))
 {
-        struct lov_io_sub *sub;
-        int rc = 0;
-
-        ENTRY;
-        cfs_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;
-        }
-        RETURN(rc);
+	struct cl_io *parent = lio->lis_cl.cis_io;
+	struct lov_io_sub *sub;
+	int rc = 0;
+
+	ENTRY;
+	list_for_each_entry(sub, &lio->lis_active, sub_linkage) {
+		rc = iofunc(sub->sub_env, &sub->sub_io);
+		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)
@@ -510,6 +944,31 @@ static void lov_io_end(const struct lu_env *env, const struct cl_io_slice *ios)
         LASSERT(rc == 0);
 }
 
+static void
+lov_io_data_version_end(const struct lu_env *env, const struct cl_io_slice *ios)
+{
+	struct lov_io *lio = cl2lov_io(env, ios);
+	struct cl_io *parent = lio->lis_cl.cis_io;
+	struct cl_data_version_io *pdv = &parent->u.ci_data_version;
+	struct lov_io_sub *sub;
+
+	ENTRY;
+	list_for_each_entry(sub, &lio->lis_active, sub_linkage) {
+		struct cl_data_version_io *sdv = &sub->sub_io.u.ci_data_version;
+
+		lov_io_end_wrapper(sub->sub_env, &sub->sub_io);
+
+		pdv->dv_data_version += sdv->dv_data_version;
+		if (pdv->dv_layout_version > sdv->dv_layout_version)
+			pdv->dv_layout_version = sdv->dv_layout_version;
+
+		if (parent->ci_result == 0)
+			parent->ci_result = sub->sub_io.ci_result;
+	}
+
+	EXIT;
+}
+
 static void lov_io_iter_fini(const struct lu_env *env,
                              const struct cl_io_slice *ios)
 {
@@ -519,8 +978,8 @@ static void lov_io_iter_fini(const struct lu_env *env,
         ENTRY;
         rc = lov_io_call(env, lio, lov_io_iter_fini_wrapper);
         LASSERT(rc == 0);
-        while (!cfs_list_empty(&lio->lis_active))
-                cfs_list_del_init(lio->lis_active.next);
+	while (!list_empty(&lio->lis_active))
+		list_del_init(lio->lis_active.next);
         EXIT;
 }
 
@@ -535,12 +994,85 @@ static void lov_io_unlock(const struct lu_env *env,
         EXIT;
 }
 
-
-static struct cl_page_list *lov_io_submit_qin(struct lov_device *ld,
-                                              struct cl_page_list *qin,
-                                              int idx, int alloc)
+static int lov_io_read_ahead(const struct lu_env *env,
+			     const struct cl_io_slice *ios,
+			     pgoff_t start, struct cl_read_ahead *ra)
 {
-        return alloc ? &qin[idx] : &ld->ld_emrg[idx]->emrg_page_list;
+	struct lov_io		*lio = cl2lov_io(env, ios);
+	struct lov_object	*loo = lio->lis_object;
+	struct cl_object	*obj = lov2cl(loo);
+	struct lov_layout_raid0 *r0;
+	struct lov_io_sub	*sub;
+	loff_t			 offset;
+	loff_t			 suboff;
+	pgoff_t			 ra_end;
+	unsigned int		 pps; /* pages per stripe */
+	int			 stripe;
+	int			 index;
+	int			 rc;
+	ENTRY;
+
+	offset = cl_offset(obj, start);
+	index = lov_io_layout_at(lio, offset);
+	if (index < 0 || !lsm_entry_inited(loo->lo_lsm, index))
+		RETURN(-ENODATA);
+
+	/* avoid readahead to expand to stale components */
+	if (!lov_entry(loo, index)->lle_valid)
+		RETURN(-EIO);
+
+	stripe = lov_stripe_number(loo->lo_lsm, index, offset);
+
+	r0 = lov_r0(loo, index);
+	if (unlikely(r0->lo_sub[stripe] == NULL))
+		RETURN(-EIO);
+
+	sub = lov_sub_get(env, lio, lov_comp_index(index, stripe));
+	if (IS_ERR(sub))
+		RETURN(PTR_ERR(sub));
+
+	lov_stripe_offset(loo->lo_lsm, index, offset, stripe, &suboff);
+	rc = cl_io_read_ahead(sub->sub_env, &sub->sub_io,
+			      cl_index(lovsub2cl(r0->lo_sub[stripe]), suboff),
+			      ra);
+
+	CDEBUG(D_READA, DFID " cra_end = %lu, stripes = %d, rc = %d\n",
+	       PFID(lu_object_fid(lov2lu(loo))), ra->cra_end, r0->lo_nr, rc);
+	if (rc != 0)
+		RETURN(rc);
+
+	/**
+	 * Adjust the stripe index by layout of comp. ra->cra_end is the
+	 * maximum page index covered by an underlying DLM lock.
+	 * This function converts cra_end from stripe level to file level, and
+	 * make sure it's not beyond stripe and component boundary.
+	 */
+
+	/* cra_end is stripe level, convert it into file level */
+	ra_end = ra->cra_end;
+	if (ra_end != CL_PAGE_EOF)
+		ra->cra_end = lov_stripe_pgoff(loo->lo_lsm, index,
+					       ra_end, stripe);
+
+	/* boundary of current component */
+	ra_end = cl_index(obj, (loff_t)lov_io_extent(lio, index)->e_end);
+	if (ra_end != CL_PAGE_EOF && ra->cra_end >= ra_end)
+		ra->cra_end = ra_end - 1;
+
+	if (r0->lo_nr == 1) /* single stripe file */
+		RETURN(0);
+
+	pps = lov_lse(loo, index)->lsme_stripe_size >> PAGE_SHIFT;
+
+	CDEBUG(D_READA, DFID " max_index = %lu, pps = %u, index = %u, "
+	       "stripe_size = %u, stripe no = %u, start index = %lu\n",
+	       PFID(lu_object_fid(lov2lu(loo))), ra->cra_end, pps, index,
+	       lov_lse(loo, index)->lsme_stripe_size, stripe, start);
+
+	/* never exceed the end of the stripe */
+	ra->cra_end = min_t(pgoff_t,
+			    ra->cra_end, start + pps - start % pps - 1);
+	RETURN(0);
 }
 
 /**
@@ -559,175 +1091,177 @@ static struct cl_page_list *lov_io_submit_qin(struct lov_device *ld,
  * 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,
-                         enum cl_req_priority priority)
-{
-        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 =
-#if defined(__KERNEL__) && defined(__linux__)
-                !(current->flags & PF_MEMALLOC);
-#else
-                1;
-#endif
-        ENTRY;
-        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, priority);
-                lov_sub_put(sub);
-                RETURN(rc);
-        }
-
-        LASSERT(lio->lis_subs != NULL);
-        if (alloc) {
-                OBD_ALLOC(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
-                 */
-                cfs_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 (cfs_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, priority);
-                        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 (cfs_list_empty(&sub_qin->pl_pages))
-                        continue;
+			 const struct cl_io_slice *ios,
+			 enum cl_req_type crt, struct cl_2queue *queue)
+{
+	struct cl_page_list	*qin = &queue->c2_qin;
+	struct lov_io		*lio = cl2lov_io(env, ios);
+	struct lov_io_sub	*sub;
+	struct cl_page_list	*plist = &lov_env_info(env)->lti_plist;
+	struct cl_page		*page;
+	int index;
+	int rc = 0;
+	ENTRY;
+
+	cl_page_list_init(plist);
+	while (qin->pl_nr > 0) {
+		struct cl_2queue  *cl2q = &lov_env_info(env)->lti_cl2q;
+
+		page = cl_page_list_first(qin);
+		if (lov_page_is_empty(page)) {
+			cl_page_list_move(&queue->c2_qout, qin, page);
+
+			/* it could only be mirror read to get here therefore
+			 * the pages will be transient. We don't care about
+			 * the return code of cl_page_prep() at all. */
+			(void) cl_page_prep(env, ios->cis_io, page, crt);
+			cl_page_completion(env, page, crt, 0);
+			continue;
+		}
+
+		cl_2queue_init(cl2q);
+		cl_page_list_move(&cl2q->c2_qin, qin, page);
+
+		index = lov_page_index(page);
+		while (qin->pl_nr > 0) {
+			page = cl_page_list_first(qin);
+			if (index != lov_page_index(page))
+				break;
+
+			cl_page_list_move(&cl2q->c2_qin, qin, page);
+		}
+
+		sub = lov_sub_get(env, lio, index);
+		if (!IS_ERR(sub)) {
+			rc = cl_io_submit_rw(sub->sub_env, &sub->sub_io,
+					     crt, cl2q);
+		} else {
+			rc = PTR_ERR(sub);
+		}
+
+		cl_page_list_splice(&cl2q->c2_qin, plist);
+		cl_page_list_splice(&cl2q->c2_qout, &queue->c2_qout);
+		cl_2queue_fini(env, cl2q);
+
+		if (rc != 0)
+			break;
+	}
+
+	cl_page_list_splice(plist, qin);
+	cl_page_list_fini(env, plist);
+
+	RETURN(rc);
+}
 
-                cl_page_list_splice(sub_qin, qin);
-        }
+static int lov_io_commit_async(const struct lu_env *env,
+			       const struct cl_io_slice *ios,
+			       struct cl_page_list *queue, int from, int to,
+			       cl_commit_cbt cb)
+{
+	struct cl_page_list *plist = &lov_env_info(env)->lti_plist;
+	struct lov_io     *lio = cl2lov_io(env, ios);
+	struct lov_io_sub *sub;
+	struct cl_page *page;
+	int rc = 0;
+	ENTRY;
+
+	if (lio->lis_nr_subios == 1) {
+		int idx = lio->lis_single_subio_index;
+
+		LASSERT(!lov_page_is_empty(cl_page_list_first(queue)));
+
+		sub = lov_sub_get(env, lio, idx);
+		LASSERT(!IS_ERR(sub));
+		LASSERT(sub == &lio->lis_single_subio);
+		rc = cl_io_commit_async(sub->sub_env, &sub->sub_io, queue,
+					from, to, cb);
+		RETURN(rc);
+	}
+
+	cl_page_list_init(plist);
+	while (queue->pl_nr > 0) {
+		int stripe_to = to;
+		int index;
+
+		LASSERT(plist->pl_nr == 0);
+		page = cl_page_list_first(queue);
+		LASSERT(!lov_page_is_empty(page));
+
+		cl_page_list_move(plist, queue, page);
+
+		index = lov_page_index(page);
+		while (queue->pl_nr > 0) {
+			page = cl_page_list_first(queue);
+			if (index != lov_page_index(page))
+				break;
+
+			cl_page_list_move(plist, queue, page);
+		}
+
+		if (queue->pl_nr > 0) /* still has more pages */
+			stripe_to = PAGE_SIZE;
+
+		sub = lov_sub_get(env, lio, index);
+		if (!IS_ERR(sub)) {
+			rc = cl_io_commit_async(sub->sub_env, &sub->sub_io,
+						plist, from, stripe_to, cb);
+		} else {
+			rc = PTR_ERR(sub);
+			break;
+		}
+
+		if (plist->pl_nr > 0) /* short write */
+			break;
+
+		from = 0;
+	}
+
+	/* for error case, add the page back into the qin list */
+	LASSERT(ergo(rc == 0, plist->pl_nr == 0));
+	while (plist->pl_nr > 0) {
+		/* error occurred, add the uncommitted pages back into queue */
+		page = cl_page_list_last(plist);
+		cl_page_list_move_head(queue, plist, page);
+	}
+
+	RETURN(rc);
+}
 
-        if (alloc) {
-                OBD_FREE(stripes_qin,
-                         sizeof(*stripes_qin) * lio->lis_nr_subios);
-        } else {
-                int i;
+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;
 
-                for (i = 0; i < lio->lis_nr_subios; i++) {
-                        struct cl_io *cio = lio->lis_subs[i].sub_io;
+	ENTRY;
 
-                        if (cio && cio == &ld->ld_emrg[i]->emrg_subio)
-                                lov_io_sub_fini(env, lio, &lio->lis_subs[i]);
-                }
-                lio->lis_mem_frozen = 0;
-                cfs_mutex_unlock(&ld->ld_mutex);
-        }
+	fio = &ios->cis_io->u.ci_fault;
+	lio = cl2lov_io(env, ios);
+	sub = lov_sub_get(env, lio, lov_page_index(fio->ft_page));
+	sub->sub_io.u.ci_fault.ft_nob = fio->ft_nob;
 
-        RETURN(rc);
-#undef QIN
+	RETURN(lov_io_start(env, ios));
 }
 
-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)
+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 cl_page    *sub_page = lov_sub_page(slice);
-        struct lov_io_sub *sub;
-        int result;
+	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;
+	ENTRY;
 
-        ENTRY;
-        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;
+	*written = 0;
+	list_for_each_entry(sub, &lio->lis_active, sub_linkage) {
+		struct cl_io *subio = &sub->sub_io;
 
-        ENTRY;
-        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);
-}
+		lov_io_end_wrapper(sub->sub_env, subio);
 
-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;
-
-        ENTRY;
-        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));
+		if (subio->ci_result == 0)
+			*written += subio->u.ci_fsync.fi_nr_written;
+	}
+	RETURN_EXIT;
 }
 
 static const struct cl_io_operations lov_io_ops = {
@@ -750,15 +1284,24 @@ static const struct cl_io_operations lov_io_ops = {
                         .cio_start     = lov_io_start,
                         .cio_end       = lov_io_end
                 },
-                [CIT_TRUNC] = {
-                        .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_SETATTR] = {
+			.cio_fini      = lov_io_fini,
+			.cio_iter_init = lov_io_setattr_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_DATA_VERSION] = {
+			.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_data_version_end,
+		},
                 [CIT_FAULT] = {
                         .cio_fini      = lov_io_fini,
                         .cio_iter_init = lov_io_iter_init,
@@ -768,20 +1311,34 @@ static const struct cl_io_operations lov_io_ops = {
                         .cio_start     = lov_io_fault_start,
                         .cio_end       = lov_io_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
+		[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_LADVISE] = {
+			.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_GLIMPSE] = {
+			.cio_fini      = lov_io_fini,
+		},
+		[CIT_MISC] = {
+			.cio_fini      = lov_io_fini
+		}
+	},
+	.cio_read_ahead		       = lov_io_read_ahead,
+	.cio_submit                    = lov_io_submit,
+	.cio_commit_async              = lov_io_commit_async,
 };
 
 /*****************************************************************************
@@ -793,8 +1350,19 @@ static const struct cl_io_operations lov_io_ops = {
 static void lov_empty_io_fini(const struct lu_env *env,
                               const struct cl_io_slice *ios)
 {
-        ENTRY;
-        EXIT;
+	struct lov_object *lov = cl2lov(ios->cis_obj);
+	ENTRY;
+
+	if (atomic_dec_and_test(&lov->lo_active_ios))
+		wake_up_all(&lov->lo_waitq);
+	EXIT;
+}
+
+static int lov_empty_io_submit(const struct lu_env *env,
+			       const struct cl_io_slice *ios,
+			       enum cl_req_type crt, struct cl_2queue *queue)
+{
+	return -EBADF;
 }
 
 static void lov_empty_impossible(const struct lu_env *env,
@@ -811,8 +1379,8 @@ static void lov_empty_impossible(const struct lu_env *env,
 static const struct cl_io_operations lov_empty_io_ops = {
         .op = {
                 [CIT_READ] = {
-#if 0
                         .cio_fini       = lov_empty_io_fini,
+#if 0
                         .cio_iter_init  = LOV_EMPTY_IMPOSSIBLE,
                         .cio_lock       = LOV_EMPTY_IMPOSSIBLE,
                         .cio_start      = LOV_EMPTY_IMPOSSIBLE,
@@ -826,7 +1394,7 @@ static const struct cl_io_operations lov_empty_io_ops = {
                         .cio_start     = LOV_EMPTY_IMPOSSIBLE,
                         .cio_end       = LOV_EMPTY_IMPOSSIBLE
                 },
-                [CIT_TRUNC] = {
+                [CIT_SETATTR] = {
                         .cio_fini      = lov_empty_io_fini,
                         .cio_iter_init = LOV_EMPTY_IMPOSSIBLE,
                         .cio_lock      = LOV_EMPTY_IMPOSSIBLE,
@@ -840,67 +1408,178 @@ static const struct cl_io_operations lov_empty_io_ops = {
                         .cio_start     = LOV_EMPTY_IMPOSSIBLE,
                         .cio_end       = LOV_EMPTY_IMPOSSIBLE
                 },
-                [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
+		[CIT_FSYNC] = {
+			.cio_fini      = lov_empty_io_fini
+		},
+		[CIT_LADVISE] = {
+			.cio_fini   = lov_empty_io_fini
+		},
+		[CIT_GLIMPSE] = {
+			.cio_fini      = lov_empty_io_fini
+		},
+		[CIT_MISC] = {
+			.cio_fini      = lov_empty_io_fini
+		}
+	},
+	.cio_submit                    = lov_empty_io_submit,
+	.cio_commit_async              = LOV_EMPTY_IMPOSSIBLE
 };
 
-int lov_io_init_raid0(const struct lu_env *env, struct cl_object *obj,
-                      struct cl_io *io)
+int lov_io_init_composite(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);
-
-        ENTRY;
-        CFS_INIT_LIST_HEAD(&lio->lis_active);
-        lov_io_slice_init(lio, lov, io);
-        if (io->ci_result == 0) {
-                LASSERT(lov_r0(lov)->lo_lsm != NULL);
-                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);
-        }
-        RETURN(io->ci_result);
+	struct lov_io       *lio = lov_env_io(env);
+	struct lov_object   *lov = cl2lov(obj);
+	int result;
+	ENTRY;
+
+	INIT_LIST_HEAD(&lio->lis_active);
+	result = lov_io_slice_init(lio, lov, io);
+	if (result)
+		GOTO(out, result);
+
+	result = lov_io_subio_init(env, lio, io);
+	if (!result) {
+		cl_io_slice_add(io, &lio->lis_cl, obj, &lov_io_ops);
+		atomic_inc(&lov->lo_active_ios);
+	}
+	EXIT;
+out:
+	io->ci_result = result < 0 ? result : 0;
+	return result;
 }
 
 int lov_io_init_empty(const struct lu_env *env, struct cl_object *obj,
                       struct cl_io *io)
 {
-        struct lov_io *lio = lov_env_io(env);
-        int result;
+	struct lov_object *lov = cl2lov(obj);
+	struct lov_io *lio = lov_env_io(env);
+	int result;
+	ENTRY;
+
+	lio->lis_object = lov;
+	switch (io->ci_type) {
+	default:
+		LBUG();
+	case CIT_MISC:
+	case CIT_GLIMPSE:
+	case CIT_READ:
+		result = 0;
+		break;
+	case CIT_FSYNC:
+	case CIT_LADVISE:
+	case CIT_SETATTR:
+	case CIT_DATA_VERSION:
+		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);
+}
 
-        ENTRY;
-        switch (io->ci_type) {
-        default:
-                LBUG();
-        case CIT_MISC:
-        case CIT_READ:
-                result = 0;
-                break;
-        case CIT_WRITE:
-        case CIT_TRUNC:
-                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);
-        io->ci_result = result;
-        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;
+	ENTRY;
+
+	LASSERT(lov->lo_lsm != NULL);
+	lio->lis_object = lov;
+
+	switch (io->ci_type) {
+	default:
+		LASSERTF(0, "invalid type %d\n", io->ci_type);
+		result = -EOPNOTSUPP;
+		break;
+	case CIT_GLIMPSE:
+	case CIT_MISC:
+	case CIT_FSYNC:
+	case CIT_LADVISE:
+	case CIT_DATA_VERSION:
+		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;
+		} else
+			result = 1;
+		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);
+}
+
+/**
+ * Return the index in composite:lo_entries by the file offset
+ */
+int lov_io_layout_at(struct lov_io *lio, __u64 offset)
+{
+	struct lov_object *lov = lio->lis_object;
+	struct lov_layout_composite *comp = &lov->u.composite;
+	int start_index = 0;
+	int end_index = comp->lo_entry_count - 1;
+	int i;
+
+	LASSERT(lov->lo_type == LLT_COMP);
+
+	/* This is actual file offset so nothing can cover eof. */
+	if (offset == LUSTRE_EOF)
+		return -1;
+
+	if (lov_is_flr(lov)) {
+		struct lov_mirror_entry *lre;
+
+		LASSERT(lio->lis_mirror_index >= 0);
+
+		lre = &comp->lo_mirrors[lio->lis_mirror_index];
+		start_index = lre->lre_start;
+		end_index = lre->lre_end;
+	}
+
+	for (i = start_index; i <= end_index; i++) {
+		struct lov_layout_entry *lle = lov_entry(lov, i);
+
+		if ((offset >= lle->lle_extent->e_start &&
+		     offset < lle->lle_extent->e_end) ||
+		    (offset == OBD_OBJECT_EOF &&
+		     lle->lle_extent->e_end == OBD_OBJECT_EOF))
+			return i;
+	}
+
+	return -1;
 }
 
 /** @} lov */