/*
 * 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) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 */

#define DEBUG_SUBSYSTEM S_LOV

#include <linux/libcfs/libcfs.h>

#include <obd_class.h>
#include <obd_lov.h>

#include "lov_internal.h"

/** Merge the lock value block(&lvb) attributes and KMS from each of the
 * stripes in a file into a single lvb. It is expected that the caller
 * initializes the current atime, mtime, ctime to avoid regressing a more
 * uptodate time on the local client.
 */
int lov_merge_lvb_kms(struct lov_stripe_md *lsm,
		      struct ost_lvb *lvb, __u64 *kms_place)
{
	__u64 size = 0;
	__u64 kms = 0;
	__u64 blocks = 0;
	obd_time current_mtime = lvb->lvb_mtime;
	obd_time current_atime = lvb->lvb_atime;
	obd_time current_ctime = lvb->lvb_ctime;
	int i;
	int rc = 0;

	LASSERT(spin_is_locked(&lsm->lsm_lock));
	LASSERT(lsm->lsm_lock_owner == current_pid());

	CDEBUG(D_INODE, "MDT ID "DOSTID" initial value: s="LPU64" m="LPU64
	       " a="LPU64" c="LPU64" b="LPU64"\n", POSTID(&lsm->lsm_oi),
	       lvb->lvb_size, lvb->lvb_mtime, lvb->lvb_atime, lvb->lvb_ctime,
	       lvb->lvb_blocks);
	for (i = 0; i < lsm->lsm_stripe_count; i++) {
		struct lov_oinfo *loi = lsm->lsm_oinfo[i];
		obd_size lov_size, tmpsize;

		if (OST_LVB_IS_ERR(loi->loi_lvb.lvb_blocks)) {
			rc = OST_LVB_GET_ERR(loi->loi_lvb.lvb_blocks);
			continue;
		}

		tmpsize = loi->loi_kms;
		lov_size = lov_stripe_size(lsm, tmpsize, i);
		if (lov_size > kms)
			kms = lov_size;

		if (loi->loi_lvb.lvb_size > tmpsize)
			tmpsize = loi->loi_lvb.lvb_size;

		lov_size = lov_stripe_size(lsm, tmpsize, i);
		if (lov_size > size)
			size = lov_size;
		/* merge blocks, mtime, atime */
		blocks += loi->loi_lvb.lvb_blocks;
		if (loi->loi_lvb.lvb_mtime > current_mtime)
			current_mtime = loi->loi_lvb.lvb_mtime;
		if (loi->loi_lvb.lvb_atime > current_atime)
			current_atime = loi->loi_lvb.lvb_atime;
		if (loi->loi_lvb.lvb_ctime > current_ctime)
			current_ctime = loi->loi_lvb.lvb_ctime;

		CDEBUG(D_INODE, "MDT ID "DOSTID" on OST[%u]: s="LPU64" m="LPU64
		       " a="LPU64" c="LPU64" b="LPU64"\n", POSTID(&lsm->lsm_oi),
		       loi->loi_ost_idx, loi->loi_lvb.lvb_size,
		       loi->loi_lvb.lvb_mtime, loi->loi_lvb.lvb_atime,
		       loi->loi_lvb.lvb_ctime, loi->loi_lvb.lvb_blocks);
	}

	*kms_place = kms;
	lvb->lvb_size = size;
	lvb->lvb_blocks = blocks;
	lvb->lvb_mtime = current_mtime;
	lvb->lvb_atime = current_atime;
	lvb->lvb_ctime = current_ctime;
	return rc;
}

/** Merge the lock value block(&lvb) attributes from each of the stripes in a
 * file into a single lvb. It is expected that the caller initializes the
 * current atime, mtime, ctime to avoid regressing a more uptodate time on
 * the local client.
 *
 * If \a kms_only is set then we do not consider the recently seen size (rss)
 * when updating the known minimum size (kms).  Even when merging RSS, we will
 * take the KMS value if it's larger.  This prevents getattr from stomping on
 * dirty cached pages which extend the file size. */
int lov_merge_lvb(struct obd_export *exp,
		  struct lov_stripe_md *lsm, struct ost_lvb *lvb, int kms_only)
{
	int   rc;
	__u64 kms;

	lov_stripe_lock(lsm);
	rc = lov_merge_lvb_kms(lsm, lvb, &kms);
	lov_stripe_unlock(lsm);
	if (kms_only)
		lvb->lvb_size = kms;

	CDEBUG(D_INODE, "merged for ID "DOSTID" s="LPU64" m="LPU64" a="LPU64
	       " c="LPU64" b="LPU64"\n", POSTID(&lsm->lsm_oi), lvb->lvb_size,
	       lvb->lvb_mtime, lvb->lvb_atime, lvb->lvb_ctime, lvb->lvb_blocks);
	return rc;
}

/* Must be called under the lov_stripe_lock() */
int lov_adjust_kms(struct obd_export *exp, struct lov_stripe_md *lsm,
		   obd_off size, int shrink)
{
	struct lov_oinfo *loi;
	int stripe = 0;
	__u64 kms;

	LASSERT(spin_is_locked(&lsm->lsm_lock));
	LASSERT(lsm->lsm_lock_owner == current_pid());

	if (shrink) {
		for (; stripe < lsm->lsm_stripe_count; stripe++) {
			struct lov_oinfo *loi = lsm->lsm_oinfo[stripe];
			kms = lov_size_to_stripe(lsm, size, stripe);
			CDEBUG(D_INODE,
			       "stripe %d KMS %sing "LPU64"->"LPU64"\n",
			       stripe, kms > loi->loi_kms ? "increase":"shrink",
			       loi->loi_kms, kms);
			loi_kms_set(loi, loi->loi_lvb.lvb_size = kms);
		}
		return 0;
	}

	if (size > 0)
		stripe = lov_stripe_number(lsm, size - 1);
	kms = lov_size_to_stripe(lsm, size, stripe);
	loi = lsm->lsm_oinfo[stripe];

	CDEBUG(D_INODE, "stripe %d KMS %sincreasing "LPU64"->"LPU64"\n",
	       stripe, kms > loi->loi_kms ? "" : "not ", loi->loi_kms, kms);
	if (kms > loi->loi_kms)
		loi_kms_set(loi, kms);

	return 0;
}

void lov_merge_attrs(struct obdo *tgt, struct obdo *src, obd_valid valid,
		     struct lov_stripe_md *lsm, int stripeno, int *set)
{
	valid &= src->o_valid;

	if (*set) {
		if (valid & OBD_MD_FLSIZE) {
			/* this handles sparse files properly */
			obd_size lov_size;

			lov_size = lov_stripe_size(lsm, src->o_size, stripeno);
			if (lov_size > tgt->o_size)
				tgt->o_size = lov_size;
		}
		if (valid & OBD_MD_FLBLOCKS)
			tgt->o_blocks += src->o_blocks;
		if (valid & OBD_MD_FLBLKSZ)
			tgt->o_blksize += src->o_blksize;
		if (valid & OBD_MD_FLCTIME && tgt->o_ctime < src->o_ctime)
			tgt->o_ctime = src->o_ctime;
		if (valid & OBD_MD_FLMTIME && tgt->o_mtime < src->o_mtime)
			tgt->o_mtime = src->o_mtime;
		if (valid & OBD_MD_FLDATAVERSION)
			tgt->o_data_version += src->o_data_version;
	} else {
		memcpy(tgt, src, sizeof(*tgt));
		tgt->o_oi = lsm->lsm_oi;
		if (valid & OBD_MD_FLSIZE)
			tgt->o_size = lov_stripe_size(lsm, src->o_size,
						      stripeno);
	}

	/* data_version needs to be valid on all stripes to be correct! */
	if (!(valid & OBD_MD_FLDATAVERSION))
		tgt->o_valid &= ~OBD_MD_FLDATAVERSION;

	*set += 1;
}