The DRBD driver

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 2365 insertions, 0 deletions

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
new file mode 100644
index 000000000000..1927acefe230
--- /dev/null
+++ b/drivers/block/drbd/drbd_nl.c
@@ -0,0 +1,2365 @@
+/*
+   drbd_nl.c
+
+   This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
+
+   Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
+   Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
+   Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
+
+   drbd is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   drbd is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with drbd; see the file COPYING.  If not, write to
+   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ */
+
+#include <linux/autoconf.h>
+#include <linux/module.h>
+#include <linux/drbd.h>
+#include <linux/in.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/slab.h>
+#include <linux/connector.h>
+#include <linux/blkpg.h>
+#include <linux/cpumask.h>
+#include "drbd_int.h"
+#include "drbd_tracing.h"
+#include "drbd_wrappers.h"
+#include <asm/unaligned.h>
+#include <linux/drbd_tag_magic.h>
+#include <linux/drbd_limits.h>
+
+static unsigned short *tl_add_blob(unsigned short *, enum drbd_tags, const void *, int);
+static unsigned short *tl_add_str(unsigned short *, enum drbd_tags, const char *);
+static unsigned short *tl_add_int(unsigned short *, enum drbd_tags, const void *);
+
+/* see get_sb_bdev and bd_claim */
+static char *drbd_m_holder = "Hands off! this is DRBD's meta data device.";
+
+/* Generate the tag_list to struct functions */
+#define NL_PACKET(name, number, fields) \
+static int name ## _from_tags(struct drbd_conf *mdev, \
+	unsigned short *tags, struct name *arg) __attribute__ ((unused)); \
+static int name ## _from_tags(struct drbd_conf *mdev, \
+	unsigned short *tags, struct name *arg) \
+{ \
+	int tag; \
+	int dlen; \
+	\
+	while ((tag = get_unaligned(tags++)) != TT_END) {	\
+		dlen = get_unaligned(tags++);			\
+		switch (tag_number(tag)) { \
+		fields \
+		default: \
+			if (tag & T_MANDATORY) { \
+				dev_err(DEV, "Unknown tag: %d\n", tag_number(tag)); \
+				return 0; \
+			} \
+		} \
+		tags = (unsigned short *)((char *)tags + dlen); \
+	} \
+	return 1; \
+}
+#define NL_INTEGER(pn, pr, member) \
+	case pn: /* D_ASSERT( tag_type(tag) == TT_INTEGER ); */ \
+		arg->member = get_unaligned((int *)(tags));	\
+		break;
+#define NL_INT64(pn, pr, member) \
+	case pn: /* D_ASSERT( tag_type(tag) == TT_INT64 ); */ \
+		arg->member = get_unaligned((u64 *)(tags));	\
+		break;
+#define NL_BIT(pn, pr, member) \
+	case pn: /* D_ASSERT( tag_type(tag) == TT_BIT ); */ \
+		arg->member = *(char *)(tags) ? 1 : 0; \
+		break;
+#define NL_STRING(pn, pr, member, len) \
+	case pn: /* D_ASSERT( tag_type(tag) == TT_STRING ); */ \
+		if (dlen > len) { \
+			dev_err(DEV, "arg too long: %s (%u wanted, max len: %u bytes)\n", \
+				#member, dlen, (unsigned int)len); \
+			return 0; \
+		} \
+		 arg->member ## _len = dlen; \
+		 memcpy(arg->member, tags, min_t(size_t, dlen, len)); \
+		 break;
+#include "linux/drbd_nl.h"
+
+/* Generate the struct to tag_list functions */
+#define NL_PACKET(name, number, fields) \
+static unsigned short* \
+name ## _to_tags(struct drbd_conf *mdev, \
+	struct name *arg, unsigned short *tags) __attribute__ ((unused)); \
+static unsigned short* \
+name ## _to_tags(struct drbd_conf *mdev, \
+	struct name *arg, unsigned short *tags) \
+{ \
+	fields \
+	return tags; \
+}
+
+#define NL_INTEGER(pn, pr, member) \
+	put_unaligned(pn | pr | TT_INTEGER, tags++);	\
+	put_unaligned(sizeof(int), tags++);		\
+	put_unaligned(arg->member, (int *)tags);	\
+	tags = (unsigned short *)((char *)tags+sizeof(int));
+#define NL_INT64(pn, pr, member) \
+	put_unaligned(pn | pr | TT_INT64, tags++);	\
+	put_unaligned(sizeof(u64), tags++);		\
+	put_unaligned(arg->member, (u64 *)tags);	\
+	tags = (unsigned short *)((char *)tags+sizeof(u64));
+#define NL_BIT(pn, pr, member) \
+	put_unaligned(pn | pr | TT_BIT, tags++);	\
+	put_unaligned(sizeof(char), tags++);		\
+	*(char *)tags = arg->member; \
+	tags = (unsigned short *)((char *)tags+sizeof(char));
+#define NL_STRING(pn, pr, member, len) \
+	put_unaligned(pn | pr | TT_STRING, tags++);	\
+	put_unaligned(arg->member ## _len, tags++);	\
+	memcpy(tags, arg->member, arg->member ## _len); \
+	tags = (unsigned short *)((char *)tags + arg->member ## _len);
+#include "linux/drbd_nl.h"
+
+void drbd_bcast_ev_helper(struct drbd_conf *mdev, char *helper_name);
+void drbd_nl_send_reply(struct cn_msg *, int);
+
+int drbd_khelper(struct drbd_conf *mdev, char *cmd)
+{
+	char *envp[] = { "HOME=/",
+			"TERM=linux",
+			"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
+			NULL, /* Will be set to address family */
+			NULL, /* Will be set to address */
+			NULL };
+
+	char mb[12], af[20], ad[60], *afs;
+	char *argv[] = {usermode_helper, cmd, mb, NULL };
+	int ret;
+
+	snprintf(mb, 12, "minor-%d", mdev_to_minor(mdev));
+
+	if (get_net_conf(mdev)) {
+		switch (((struct sockaddr *)mdev->net_conf->peer_addr)->sa_family) {
+		case AF_INET6:
+			afs = "ipv6";
+			snprintf(ad, 60, "DRBD_PEER_ADDRESS=%pI6",
+				 &((struct sockaddr_in6 *)mdev->net_conf->peer_addr)->sin6_addr);
+			break;
+		case AF_INET:
+			afs = "ipv4";
+			snprintf(ad, 60, "DRBD_PEER_ADDRESS=%pI4",
+				 &((struct sockaddr_in *)mdev->net_conf->peer_addr)->sin_addr);
+			break;
+		default:
+			afs = "ssocks";
+			snprintf(ad, 60, "DRBD_PEER_ADDRESS=%pI4",
+				 &((struct sockaddr_in *)mdev->net_conf->peer_addr)->sin_addr);
+		}
+		snprintf(af, 20, "DRBD_PEER_AF=%s", afs);
+		envp[3]=af;
+		envp[4]=ad;
+		put_net_conf(mdev);
+	}
+
+	dev_info(DEV, "helper command: %s %s %s\n", usermode_helper, cmd, mb);
+
+	drbd_bcast_ev_helper(mdev, cmd);
+	ret = call_usermodehelper(usermode_helper, argv, envp, 1);
+	if (ret)
+		dev_warn(DEV, "helper command: %s %s %s exit code %u (0x%x)\n",
+				usermode_helper, cmd, mb,
+				(ret >> 8) & 0xff, ret);
+	else
+		dev_info(DEV, "helper command: %s %s %s exit code %u (0x%x)\n",
+				usermode_helper, cmd, mb,
+				(ret >> 8) & 0xff, ret);
+
+	if (ret < 0) /* Ignore any ERRNOs we got. */
+		ret = 0;
+
+	return ret;
+}
+
+enum drbd_disk_state drbd_try_outdate_peer(struct drbd_conf *mdev)
+{
+	char *ex_to_string;
+	int r;
+	enum drbd_disk_state nps;
+	enum drbd_fencing_p fp;
+
+	D_ASSERT(mdev->state.pdsk == D_UNKNOWN);
+
+	if (get_ldev_if_state(mdev, D_CONSISTENT)) {
+		fp = mdev->ldev->dc.fencing;
+		put_ldev(mdev);
+	} else {
+		dev_warn(DEV, "Not fencing peer, I'm not even Consistent myself.\n");
+		return mdev->state.pdsk;
+	}
+
+	if (fp == FP_STONITH)
+		_drbd_request_state(mdev, NS(susp, 1), CS_WAIT_COMPLETE);
+
+	r = drbd_khelper(mdev, "fence-peer");
+
+	switch ((r>>8) & 0xff) {
+	case 3: /* peer is inconsistent */
+		ex_to_string = "peer is inconsistent or worse";
+		nps = D_INCONSISTENT;
+		break;
+	case 4: /* peer got outdated, or was already outdated */
+		ex_to_string = "peer was fenced";
+		nps = D_OUTDATED;
+		break;
+	case 5: /* peer was down */
+		if (mdev->state.disk == D_UP_TO_DATE) {
+			/* we will(have) create(d) a new UUID anyways... */
+			ex_to_string = "peer is unreachable, assumed to be dead";
+			nps = D_OUTDATED;
+		} else {
+			ex_to_string = "peer unreachable, doing nothing since disk != UpToDate";
+			nps = mdev->state.pdsk;
+		}
+		break;
+	case 6: /* Peer is primary, voluntarily outdate myself.
+		 * This is useful when an unconnected R_SECONDARY is asked to
+		 * become R_PRIMARY, but finds the other peer being active. */
+		ex_to_string = "peer is active";
+		dev_warn(DEV, "Peer is primary, outdating myself.\n");
+		nps = D_UNKNOWN;
+		_drbd_request_state(mdev, NS(disk, D_OUTDATED), CS_WAIT_COMPLETE);
+		break;
+	case 7:
+		if (fp != FP_STONITH)
+			dev_err(DEV, "fence-peer() = 7 && fencing != Stonith !!!\n");
+		ex_to_string = "peer was stonithed";
+		nps = D_OUTDATED;
+		break;
+	default:
+		/* The script is broken ... */
+		nps = D_UNKNOWN;
+		dev_err(DEV, "fence-peer helper broken, returned %d\n", (r>>8)&0xff);
+		return nps;
+	}
+
+	dev_info(DEV, "fence-peer helper returned %d (%s)\n",
+			(r>>8) & 0xff, ex_to_string);
+	return nps;
+}
+
+
+int drbd_set_role(struct drbd_conf *mdev, enum drbd_role new_role, int force)
+{
+	const int max_tries = 4;
+	int r = 0;
+	int try = 0;
+	int forced = 0;
+	union drbd_state mask, val;
+	enum drbd_disk_state nps;
+
+	if (new_role == R_PRIMARY)
+		request_ping(mdev); /* Detect a dead peer ASAP */
+
+	mutex_lock(&mdev->state_mutex);
+
+	mask.i = 0; mask.role = R_MASK;
+	val.i  = 0; val.role  = new_role;
+
+	while (try++ < max_tries) {
+		r = _drbd_request_state(mdev, mask, val, CS_WAIT_COMPLETE);
+
+		/* in case we first succeeded to outdate,
+		 * but now suddenly could establish a connection */
+		if (r == SS_CW_FAILED_BY_PEER && mask.pdsk != 0) {
+			val.pdsk = 0;
+			mask.pdsk = 0;
+			continue;
+		}
+
+		if (r == SS_NO_UP_TO_DATE_DISK && force &&
+		    (mdev->state.disk == D_INCONSISTENT ||
+		     mdev->state.disk == D_OUTDATED)) {
+			mask.disk = D_MASK;
+			val.disk  = D_UP_TO_DATE;
+			forced = 1;
+			continue;
+		}
+
+		if (r == SS_NO_UP_TO_DATE_DISK &&
+		    mdev->state.disk == D_CONSISTENT && mask.pdsk == 0) {
+			D_ASSERT(mdev->state.pdsk == D_UNKNOWN);
+			nps = drbd_try_outdate_peer(mdev);
+
+			if (nps == D_OUTDATED || nps == D_INCONSISTENT) {
+				val.disk = D_UP_TO_DATE;
+				mask.disk = D_MASK;
+			}
+
+			val.pdsk = nps;
+			mask.pdsk = D_MASK;
+
+			continue;
+		}
+
+		if (r == SS_NOTHING_TO_DO)
+			goto fail;
+		if (r == SS_PRIMARY_NOP && mask.pdsk == 0) {
+			nps = drbd_try_outdate_peer(mdev);
+
+			if (force && nps > D_OUTDATED) {
+				dev_warn(DEV, "Forced into split brain situation!\n");
+				nps = D_OUTDATED;
+			}
+
+			mask.pdsk = D_MASK;
+			val.pdsk  = nps;
+
+			continue;
+		}
+		if (r == SS_TWO_PRIMARIES) {
+			/* Maybe the peer is detected as dead very soon...
+			   retry at most once more in this case. */
+			__set_current_state(TASK_INTERRUPTIBLE);
+			schedule_timeout((mdev->net_conf->ping_timeo+1)*HZ/10);
+			if (try < max_tries)
+				try = max_tries - 1;
+			continue;
+		}
+		if (r < SS_SUCCESS) {
+			r = _drbd_request_state(mdev, mask, val,
+						CS_VERBOSE + CS_WAIT_COMPLETE);
+			if (r < SS_SUCCESS)
+				goto fail;
+		}
+		break;
+	}
+
+	if (r < SS_SUCCESS)
+		goto fail;
+
+	if (forced)
+		dev_warn(DEV, "Forced to consider local data as UpToDate!\n");
+
+	/* Wait until nothing is on the fly :) */
+	wait_event(mdev->misc_wait, atomic_read(&mdev->ap_pending_cnt) == 0);
+
+	if (new_role == R_SECONDARY) {
+		set_disk_ro(mdev->vdisk, TRUE);
+		if (get_ldev(mdev)) {
+			mdev->ldev->md.uuid[UI_CURRENT] &= ~(u64)1;
+			put_ldev(mdev);
+		}
+	} else {
+		if (get_net_conf(mdev)) {
+			mdev->net_conf->want_lose = 0;
+			put_net_conf(mdev);
+		}
+		set_disk_ro(mdev->vdisk, FALSE);
+		if (get_ldev(mdev)) {
+			if (((mdev->state.conn < C_CONNECTED ||
+			       mdev->state.pdsk <= D_FAILED)
+			      && mdev->ldev->md.uuid[UI_BITMAP] == 0) || forced)
+				drbd_uuid_new_current(mdev);
+
+			mdev->ldev->md.uuid[UI_CURRENT] |=  (u64)1;
+			put_ldev(mdev);
+		}
+	}
+
+	if ((new_role == R_SECONDARY) && get_ldev(mdev)) {
+		drbd_al_to_on_disk_bm(mdev);
+		put_ldev(mdev);
+	}
+
+	if (mdev->state.conn >= C_WF_REPORT_PARAMS) {
+		/* if this was forced, we should consider sync */
+		if (forced)
+			drbd_send_uuids(mdev);
+		drbd_send_state(mdev);
+	}
+
+	drbd_md_sync(mdev);
+
+	kobject_uevent(&disk_to_dev(mdev->vdisk)->kobj, KOBJ_CHANGE);
+ fail:
+	mutex_unlock(&mdev->state_mutex);
+	return r;
+}
+
+
+static int drbd_nl_primary(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			   struct drbd_nl_cfg_reply *reply)
+{
+	struct primary primary_args;
+
+	memset(&primary_args, 0, sizeof(struct primary));
+	if (!primary_from_tags(mdev, nlp->tag_list, &primary_args)) {
+		reply->ret_code = ERR_MANDATORY_TAG;
+		return 0;
+	}
+
+	reply->ret_code =
+		drbd_set_role(mdev, R_PRIMARY, primary_args.overwrite_peer);
+
+	return 0;
+}
+
+static int drbd_nl_secondary(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			     struct drbd_nl_cfg_reply *reply)
+{
+	reply->ret_code = drbd_set_role(mdev, R_SECONDARY, 0);
+
+	return 0;
+}
+
+/* initializes the md.*_offset members, so we are able to find
+ * the on disk meta data */
+static void drbd_md_set_sector_offsets(struct drbd_conf *mdev,
+				       struct drbd_backing_dev *bdev)
+{
+	sector_t md_size_sect = 0;
+	switch (bdev->dc.meta_dev_idx) {
+	default:
+		/* v07 style fixed size indexed meta data */
+		bdev->md.md_size_sect = MD_RESERVED_SECT;
+		bdev->md.md_offset = drbd_md_ss__(mdev, bdev);
+		bdev->md.al_offset = MD_AL_OFFSET;
+		bdev->md.bm_offset = MD_BM_OFFSET;
+		break;
+	case DRBD_MD_INDEX_FLEX_EXT:
+		/* just occupy the full device; unit: sectors */
+		bdev->md.md_size_sect = drbd_get_capacity(bdev->md_bdev);
+		bdev->md.md_offset = 0;
+		bdev->md.al_offset = MD_AL_OFFSET;
+		bdev->md.bm_offset = MD_BM_OFFSET;
+		break;
+	case DRBD_MD_INDEX_INTERNAL:
+	case DRBD_MD_INDEX_FLEX_INT:
+		bdev->md.md_offset = drbd_md_ss__(mdev, bdev);
+		/* al size is still fixed */
+		bdev->md.al_offset = -MD_AL_MAX_SIZE;
+		/* we need (slightly less than) ~ this much bitmap sectors: */
+		md_size_sect = drbd_get_capacity(bdev->backing_bdev);
+		md_size_sect = ALIGN(md_size_sect, BM_SECT_PER_EXT);
+		md_size_sect = BM_SECT_TO_EXT(md_size_sect);
+		md_size_sect = ALIGN(md_size_sect, 8);
+
+		/* plus the "drbd meta data super block",
+		 * and the activity log; */
+		md_size_sect += MD_BM_OFFSET;
+
+		bdev->md.md_size_sect = md_size_sect;
+		/* bitmap offset is adjusted by 'super' block size */
+		bdev->md.bm_offset   = -md_size_sect + MD_AL_OFFSET;
+		break;
+	}
+}
+
+char *ppsize(char *buf, unsigned long long size)
+{
+	/* Needs 9 bytes at max. */
+	static char units[] = { 'K', 'M', 'G', 'T', 'P', 'E' };
+	int base = 0;
+	while (size >= 10000) {
+		/* shift + round */
+		size = (size >> 10) + !!(size & (1<<9));
+		base++;
+	}
+	sprintf(buf, "%lu %cB", (long)size, units[base]);
+
+	return buf;
+}
+
+/* there is still a theoretical deadlock when called from receiver
+ * on an D_INCONSISTENT R_PRIMARY:
+ *  remote READ does inc_ap_bio, receiver would need to receive answer
+ *  packet from remote to dec_ap_bio again.
+ *  receiver receive_sizes(), comes here,
+ *  waits for ap_bio_cnt == 0. -> deadlock.
+ * but this cannot happen, actually, because:
+ *  R_PRIMARY D_INCONSISTENT, and peer's disk is unreachable
+ *  (not connected, or bad/no disk on peer):
+ *  see drbd_fail_request_early, ap_bio_cnt is zero.
+ *  R_PRIMARY D_INCONSISTENT, and C_SYNC_TARGET:
+ *  peer may not initiate a resize.
+ */
+void drbd_suspend_io(struct drbd_conf *mdev)
+{
+	set_bit(SUSPEND_IO, &mdev->flags);
+	wait_event(mdev->misc_wait, !atomic_read(&mdev->ap_bio_cnt));
+}
+
+void drbd_resume_io(struct drbd_conf *mdev)
+{
+	clear_bit(SUSPEND_IO, &mdev->flags);
+	wake_up(&mdev->misc_wait);
+}
+
+/**
+ * drbd_determine_dev_size() -  Sets the right device size obeying all constraints
+ * @mdev:	DRBD device.
+ *
+ * Returns 0 on success, negative return values indicate errors.
+ * You should call drbd_md_sync() after calling this function.
+ */
+enum determine_dev_size drbd_determin_dev_size(struct drbd_conf *mdev) __must_hold(local)
+{
+	sector_t prev_first_sect, prev_size; /* previous meta location */
+	sector_t la_size;
+	sector_t size;
+	char ppb[10];
+
+	int md_moved, la_size_changed;
+	enum determine_dev_size rv = unchanged;
+
+	/* race:
+	 * application request passes inc_ap_bio,
+	 * but then cannot get an AL-reference.
+	 * this function later may wait on ap_bio_cnt == 0. -> deadlock.
+	 *
+	 * to avoid that:
+	 * Suspend IO right here.
+	 * still lock the act_log to not trigger ASSERTs there.
+	 */
+	drbd_suspend_io(mdev);
+
+	/* no wait necessary anymore, actually we could assert that */
+	wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
+
+	prev_first_sect = drbd_md_first_sector(mdev->ldev);
+	prev_size = mdev->ldev->md.md_size_sect;
+	la_size = mdev->ldev->md.la_size_sect;
+
+	/* TODO: should only be some assert here, not (re)init... */
+	drbd_md_set_sector_offsets(mdev, mdev->ldev);
+
+	size = drbd_new_dev_size(mdev, mdev->ldev);
+
+	if (drbd_get_capacity(mdev->this_bdev) != size ||
+	    drbd_bm_capacity(mdev) != size) {
+		int err;
+		err = drbd_bm_resize(mdev, size);
+		if (unlikely(err)) {
+			/* currently there is only one error: ENOMEM! */
+			size = drbd_bm_capacity(mdev)>>1;
+			if (size == 0) {
+				dev_err(DEV, "OUT OF MEMORY! "
+				    "Could not allocate bitmap!\n");
+			} else {
+				dev_err(DEV, "BM resizing failed. "
+				    "Leaving size unchanged at size = %lu KB\n",
+				    (unsigned long)size);
+			}
+			rv = dev_size_error;
+		}
+		/* racy, see comments above. */
+		drbd_set_my_capacity(mdev, size);
+		mdev->ldev->md.la_size_sect = size;
+		dev_info(DEV, "size = %s (%llu KB)\n", ppsize(ppb, size>>1),
+		     (unsigned long long)size>>1);
+	}
+	if (rv == dev_size_error)
+		goto out;
+
+	la_size_changed = (la_size != mdev->ldev->md.la_size_sect);
+
+	md_moved = prev_first_sect != drbd_md_first_sector(mdev->ldev)
+		|| prev_size	   != mdev->ldev->md.md_size_sect;
+
+	if (la_size_changed || md_moved) {
+		drbd_al_shrink(mdev); /* All extents inactive. */
+		dev_info(DEV, "Writing the whole bitmap, %s\n",
+			 la_size_changed && md_moved ? "size changed and md moved" :
+			 la_size_changed ? "size changed" : "md moved");
+		rv = drbd_bitmap_io(mdev, &drbd_bm_write, "size changed"); /* does drbd_resume_io() ! */
+		drbd_md_mark_dirty(mdev);
+	}
+
+	if (size > la_size)
+		rv = grew;
+	if (size < la_size)
+		rv = shrunk;
+out:
+	lc_unlock(mdev->act_log);
+	wake_up(&mdev->al_wait);
+	drbd_resume_io(mdev);
+
+	return rv;
+}
+
+sector_t
+drbd_new_dev_size(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
+{
+	sector_t p_size = mdev->p_size;   /* partner's disk size. */
+	sector_t la_size = bdev->md.la_size_sect; /* last agreed size. */
+	sector_t m_size; /* my size */
+	sector_t u_size = bdev->dc.disk_size; /* size requested by user. */
+	sector_t size = 0;
+
+	m_size = drbd_get_max_capacity(bdev);
+
+	if (p_size && m_size) {
+		size = min_t(sector_t, p_size, m_size);
+	} else {
+		if (la_size) {
+			size = la_size;
+			if (m_size && m_size < size)
+				size = m_size;
+			if (p_size && p_size < size)
+				size = p_size;
+		} else {
+			if (m_size)
+				size = m_size;
+			if (p_size)
+				size = p_size;
+		}
+	}
+
+	if (size == 0)
+		dev_err(DEV, "Both nodes diskless!\n");
+
+	if (u_size) {
+		if (u_size > size)
+			dev_err(DEV, "Requested disk size is too big (%lu > %lu)\n",
+			    (unsigned long)u_size>>1, (unsigned long)size>>1);
+		else
+			size = u_size;
+	}
+
+	return size;
+}
+
+/**
+ * drbd_check_al_size() - Ensures that the AL is of the right size
+ * @mdev:	DRBD device.
+ *
+ * Returns -EBUSY if current al lru is still used, -ENOMEM when allocation
+ * failed, and 0 on success. You should call drbd_md_sync() after you called
+ * this function.
+ */
+static int drbd_check_al_size(struct drbd_conf *mdev)
+{
+	struct lru_cache *n, *t;
+	struct lc_element *e;
+	unsigned int in_use;
+	int i;
+
+	ERR_IF(mdev->sync_conf.al_extents < 7)
+		mdev->sync_conf.al_extents = 127;
+
+	if (mdev->act_log &&
+	    mdev->act_log->nr_elements == mdev->sync_conf.al_extents)
+		return 0;
+
+	in_use = 0;
+	t = mdev->act_log;
+	n = lc_create("act_log", drbd_al_ext_cache,
+		mdev->sync_conf.al_extents, sizeof(struct lc_element), 0);
+
+	if (n == NULL) {
+		dev_err(DEV, "Cannot allocate act_log lru!\n");
+		return -ENOMEM;
+	}
+	spin_lock_irq(&mdev->al_lock);
+	if (t) {
+		for (i = 0; i < t->nr_elements; i++) {
+			e = lc_element_by_index(t, i);
+			if (e->refcnt)
+				dev_err(DEV, "refcnt(%d)==%d\n",
+				    e->lc_number, e->refcnt);
+			in_use += e->refcnt;
+		}
+	}
+	if (!in_use)
+		mdev->act_log = n;
+	spin_unlock_irq(&mdev->al_lock);
+	if (in_use) {
+		dev_err(DEV, "Activity log still in use!\n");
+		lc_destroy(n);
+		return -EBUSY;
+	} else {
+		if (t)
+			lc_destroy(t);
+	}
+	drbd_md_mark_dirty(mdev); /* we changed mdev->act_log->nr_elemens */
+	return 0;
+}
+
+void drbd_setup_queue_param(struct drbd_conf *mdev, unsigned int max_seg_s) __must_hold(local)
+{
+	struct request_queue * const q = mdev->rq_queue;
+	struct request_queue * const b = mdev->ldev->backing_bdev->bd_disk->queue;
+	int max_segments = mdev->ldev->dc.max_bio_bvecs;
+
+	if (b->merge_bvec_fn && !mdev->ldev->dc.use_bmbv)
+		max_seg_s = PAGE_SIZE;
+
+	max_seg_s = min(queue_max_sectors(b) * queue_logical_block_size(b), max_seg_s);
+
+	blk_queue_max_sectors(q, max_seg_s >> 9);
+	blk_queue_max_phys_segments(q, max_segments ? max_segments : MAX_PHYS_SEGMENTS);
+	blk_queue_max_hw_segments(q, max_segments ? max_segments : MAX_HW_SEGMENTS);
+	blk_queue_max_segment_size(q, max_seg_s);
+	blk_queue_logical_block_size(q, 512);
+	blk_queue_segment_boundary(q, PAGE_SIZE-1);
+	blk_stack_limits(&q->limits, &b->limits, 0);
+
+	if (b->merge_bvec_fn)
+		dev_warn(DEV, "Backing device's merge_bvec_fn() = %p\n",
+		     b->merge_bvec_fn);
+	dev_info(DEV, "max_segment_size ( = BIO size ) = %u\n", queue_max_segment_size(q));
+
+	if (q->backing_dev_info.ra_pages != b->backing_dev_info.ra_pages) {
+		dev_info(DEV, "Adjusting my ra_pages to backing device's (%lu -> %lu)\n",
+		     q->backing_dev_info.ra_pages,
+		     b->backing_dev_info.ra_pages);
+		q->backing_dev_info.ra_pages = b->backing_dev_info.ra_pages;
+	}
+}
+
+/* serialize deconfig (worker exiting, doing cleanup)
+ * and reconfig (drbdsetup disk, drbdsetup net)
+ *
+ * wait for a potentially exiting worker, then restart it,
+ * or start a new one.
+ */
+static void drbd_reconfig_start(struct drbd_conf *mdev)
+{
+	wait_event(mdev->state_wait, test_and_set_bit(CONFIG_PENDING, &mdev->flags));
+	wait_event(mdev->state_wait, !test_bit(DEVICE_DYING, &mdev->flags));
+	drbd_thread_start(&mdev->worker);
+}
+
+/* if still unconfigured, stops worker again.
+ * if configured now, clears CONFIG_PENDING.
+ * wakes potential waiters */
+static void drbd_reconfig_done(struct drbd_conf *mdev)
+{
+	spin_lock_irq(&mdev->req_lock);
+	if (mdev->state.disk == D_DISKLESS &&
+	    mdev->state.conn == C_STANDALONE &&
+	    mdev->state.role == R_SECONDARY) {
+		set_bit(DEVICE_DYING, &mdev->flags);
+		drbd_thread_stop_nowait(&mdev->worker);
+	} else
+		clear_bit(CONFIG_PENDING, &mdev->flags);
+	spin_unlock_irq(&mdev->req_lock);
+	wake_up(&mdev->state_wait);
+}
+
+/* does always return 0;
+ * interesting return code is in reply->ret_code */
+static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			     struct drbd_nl_cfg_reply *reply)
+{
+	enum drbd_ret_codes retcode;
+	enum determine_dev_size dd;
+	sector_t max_possible_sectors;
+	sector_t min_md_device_sectors;
+	struct drbd_backing_dev *nbc = NULL; /* new_backing_conf */
+	struct inode *inode, *inode2;
+	struct lru_cache *resync_lru = NULL;
+	union drbd_state ns, os;
+	int rv;
+	int cp_discovered = 0;
+	int logical_block_size;
+
+	drbd_reconfig_start(mdev);
+
+	/* if you want to reconfigure, please tear down first */
+	if (mdev->state.disk > D_DISKLESS) {
+		retcode = ERR_DISK_CONFIGURED;
+		goto fail;
+	}
+
+	/* allocation not in the IO path, cqueue thread context */
+	nbc = kzalloc(sizeof(struct drbd_backing_dev), GFP_KERNEL);
+	if (!nbc) {
+		retcode = ERR_NOMEM;
+		goto fail;
+	}
+
+	nbc->dc.disk_size     = DRBD_DISK_SIZE_SECT_DEF;
+	nbc->dc.on_io_error   = DRBD_ON_IO_ERROR_DEF;
+	nbc->dc.fencing       = DRBD_FENCING_DEF;
+	nbc->dc.max_bio_bvecs = DRBD_MAX_BIO_BVECS_DEF;
+
+	if (!disk_conf_from_tags(mdev, nlp->tag_list, &nbc->dc)) {
+		retcode = ERR_MANDATORY_TAG;
+		goto fail;
+	}
+
+	if (nbc->dc.meta_dev_idx < DRBD_MD_INDEX_FLEX_INT) {
+		retcode = ERR_MD_IDX_INVALID;
+		goto fail;
+	}
+
+	nbc->lo_file = filp_open(nbc->dc.backing_dev, O_RDWR, 0);
+	if (IS_ERR(nbc->lo_file)) {
+		dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.backing_dev,
+		    PTR_ERR(nbc->lo_file));
+		nbc->lo_file = NULL;
+		retcode = ERR_OPEN_DISK;
+		goto fail;
+	}
+
+	inode = nbc->lo_file->f_dentry->d_inode;
+
+	if (!S_ISBLK(inode->i_mode)) {
+		retcode = ERR_DISK_NOT_BDEV;
+		goto fail;
+	}
+
+	nbc->md_file = filp_open(nbc->dc.meta_dev, O_RDWR, 0);
+	if (IS_ERR(nbc->md_file)) {
+		dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.meta_dev,
+		    PTR_ERR(nbc->md_file));
+		nbc->md_file = NULL;
+		retcode = ERR_OPEN_MD_DISK;
+		goto fail;
+	}
+
+	inode2 = nbc->md_file->f_dentry->d_inode;
+
+	if (!S_ISBLK(inode2->i_mode)) {
+		retcode = ERR_MD_NOT_BDEV;
+		goto fail;
+	}
+
+	nbc->backing_bdev = inode->i_bdev;
+	if (bd_claim(nbc->backing_bdev, mdev)) {
+		printk(KERN_ERR "drbd: bd_claim(%p,%p); failed [%p;%p;%u]\n",
+		       nbc->backing_bdev, mdev,
+		       nbc->backing_bdev->bd_holder,
+		       nbc->backing_bdev->bd_contains->bd_holder,
+		       nbc->backing_bdev->bd_holders);
+		retcode = ERR_BDCLAIM_DISK;
+		goto fail;
+	}
+
+	resync_lru = lc_create("resync", drbd_bm_ext_cache,
+			61, sizeof(struct bm_extent),
+			offsetof(struct bm_extent, lce));
+	if (!resync_lru) {
+		retcode = ERR_NOMEM;
+		goto release_bdev_fail;
+	}
+
+	/* meta_dev_idx >= 0: external fixed size,
+	 * possibly multiple drbd sharing one meta device.
+	 * TODO in that case, paranoia check that [md_bdev, meta_dev_idx] is
+	 * not yet used by some other drbd minor!
+	 * (if you use drbd.conf + drbdadm,
+	 * that should check it for you already; but if you don't, or someone
+	 * fooled it, we need to double check here) */
+	nbc->md_bdev = inode2->i_bdev;
+	if (bd_claim(nbc->md_bdev, (nbc->dc.meta_dev_idx < 0) ? (void *)mdev
+				: (void *) drbd_m_holder)) {
+		retcode = ERR_BDCLAIM_MD_DISK;
+		goto release_bdev_fail;
+	}
+
+	if ((nbc->backing_bdev == nbc->md_bdev) !=
+	    (nbc->dc.meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
+	     nbc->dc.meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)) {
+		retcode = ERR_MD_IDX_INVALID;
+		goto release_bdev2_fail;
+	}
+
+	/* RT - for drbd_get_max_capacity() DRBD_MD_INDEX_FLEX_INT */
+	drbd_md_set_sector_offsets(mdev, nbc);
+
+	if (drbd_get_max_capacity(nbc) < nbc->dc.disk_size) {
+		dev_err(DEV, "max capacity %llu smaller than disk size %llu\n",
+			(unsigned long long) drbd_get_max_capacity(nbc),
+			(unsigned long long) nbc->dc.disk_size);
+		retcode = ERR_DISK_TO_SMALL;
+		goto release_bdev2_fail;
+	}
+
+	if (nbc->dc.meta_dev_idx < 0) {
+		max_possible_sectors = DRBD_MAX_SECTORS_FLEX;
+		/* at least one MB, otherwise it does not make sense */
+		min_md_device_sectors = (2<<10);
+	} else {
+		max_possible_sectors = DRBD_MAX_SECTORS;
+		min_md_device_sectors = MD_RESERVED_SECT * (nbc->dc.meta_dev_idx + 1);
+	}
+
+	if (drbd_get_capacity(nbc->md_bdev) > max_possible_sectors)
+		dev_warn(DEV, "truncating very big lower level device "
+		     "to currently maximum possible %llu sectors\n",
+		     (unsigned long long) max_possible_sectors);
+
+	if (drbd_get_capacity(nbc->md_bdev) < min_md_device_sectors) {
+		retcode = ERR_MD_DISK_TO_SMALL;
+		dev_warn(DEV, "refusing attach: md-device too small, "
+		     "at least %llu sectors needed for this meta-disk type\n",
+		     (unsigned long long) min_md_device_sectors);
+		goto release_bdev2_fail;
+	}
+
+	/* Make sure the new disk is big enough
+	 * (we may currently be R_PRIMARY with no local disk...) */
+	if (drbd_get_max_capacity(nbc) <
+	    drbd_get_capacity(mdev->this_bdev)) {
+		retcode = ERR_DISK_TO_SMALL;
+		goto release_bdev2_fail;
+	}
+
+	nbc->known_size = drbd_get_capacity(nbc->backing_bdev);
+
+	drbd_suspend_io(mdev);
+	/* also wait for the last barrier ack. */
+	wait_event(mdev->misc_wait, !atomic_read(&mdev->ap_pending_cnt));
+	/* and for any other previously queued work */
+	drbd_flush_workqueue(mdev);
+
+	retcode = _drbd_request_state(mdev, NS(disk, D_ATTACHING), CS_VERBOSE);
+	drbd_resume_io(mdev);
+	if (retcode < SS_SUCCESS)
+		goto release_bdev2_fail;
+
+	if (!get_ldev_if_state(mdev, D_ATTACHING))
+		goto force_diskless;
+
+	drbd_md_set_sector_offsets(mdev, nbc);
+
+	if (!mdev->bitmap) {
+		if (drbd_bm_init(mdev)) {
+			retcode = ERR_NOMEM;
+			goto force_diskless_dec;
+		}
+	}
+
+	retcode = drbd_md_read(mdev, nbc);
+	if (retcode != NO_ERROR)
+		goto force_diskless_dec;
+
+	if (mdev->state.conn < C_CONNECTED &&
+	    mdev->state.role == R_PRIMARY &&
+	    (mdev->ed_uuid & ~((u64)1)) != (nbc->md.uuid[UI_CURRENT] & ~((u64)1))) {
+		dev_err(DEV, "Can only attach to data with current UUID=%016llX\n",
+		    (unsigned long long)mdev->ed_uuid);
+		retcode = ERR_DATA_NOT_CURRENT;
+		goto force_diskless_dec;
+	}
+
+	/* Since we are diskless, fix the activity log first... */
+	if (drbd_check_al_size(mdev)) {
+		retcode = ERR_NOMEM;
+		goto force_diskless_dec;
+	}
+
+	/* Prevent shrinking of consistent devices ! */
+	if (drbd_md_test_flag(nbc, MDF_CONSISTENT) &&
+	   drbd_new_dev_size(mdev, nbc) < nbc->md.la_size_sect) {
+		dev_warn(DEV, "refusing to truncate a consistent device\n");
+		retcode = ERR_DISK_TO_SMALL;
+		goto force_diskless_dec;
+	}
+
+	if (!drbd_al_read_log(mdev, nbc)) {
+		retcode = ERR_IO_MD_DISK;
+		goto force_diskless_dec;
+	}
+
+	/* allocate a second IO page if logical_block_size != 512 */
+	logical_block_size = bdev_logical_block_size(nbc->md_bdev);
+	if (logical_block_size == 0)
+		logical_block_size = MD_SECTOR_SIZE;
+
+	if (logical_block_size != MD_SECTOR_SIZE) {
+		if (!mdev->md_io_tmpp) {
+			struct page *page = alloc_page(GFP_NOIO);
+			if (!page)
+				goto force_diskless_dec;
+
+			dev_warn(DEV, "Meta data's bdev logical_block_size = %d != %d\n",
+			     logical_block_size, MD_SECTOR_SIZE);
+			dev_warn(DEV, "Workaround engaged (has performance impact).\n");
+
+			mdev->md_io_tmpp = page;
+		}
+	}
+
+	/* Reset the "barriers don't work" bits here, then force meta data to
+	 * be written, to ensure we determine if barriers are supported. */
+	if (nbc->dc.no_md_flush)
+		set_bit(MD_NO_BARRIER, &mdev->flags);
+	else
+		clear_bit(MD_NO_BARRIER, &mdev->flags);
+
+	/* Point of no return reached.
+	 * Devices and memory are no longer released by error cleanup below.
+	 * now mdev takes over responsibility, and the state engine should
+	 * clean it up somewhere.  */
+	D_ASSERT(mdev->ldev == NULL);
+	mdev->ldev = nbc;
+	mdev->resync = resync_lru;
+	nbc = NULL;
+	resync_lru = NULL;
+
+	mdev->write_ordering = WO_bio_barrier;
+	drbd_bump_write_ordering(mdev, WO_bio_barrier);
+
+	if (drbd_md_test_flag(mdev->ldev, MDF_CRASHED_PRIMARY))
+		set_bit(CRASHED_PRIMARY, &mdev->flags);
+	else
+		clear_bit(CRASHED_PRIMARY, &mdev->flags);
+
+	if (drbd_md_test_flag(mdev->ldev, MDF_PRIMARY_IND)) {
+		set_bit(CRASHED_PRIMARY, &mdev->flags);
+		cp_discovered = 1;
+	}
+
+	mdev->send_cnt = 0;
+	mdev->recv_cnt = 0;
+	mdev->read_cnt = 0;
+	mdev->writ_cnt = 0;
+
+	drbd_setup_queue_param(mdev, DRBD_MAX_SEGMENT_SIZE);
+
+	/* If I am currently not R_PRIMARY,
+	 * but meta data primary indicator is set,
+	 * I just now recover from a hard crash,
+	 * and have been R_PRIMARY before that crash.
+	 *
+	 * Now, if I had no connection before that crash
+	 * (have been degraded R_PRIMARY), chances are that
+	 * I won't find my peer now either.
+	 *
+	 * In that case, and _only_ in that case,
+	 * we use the degr-wfc-timeout instead of the default,
+	 * so we can automatically recover from a crash of a
+	 * degraded but active "cluster" after a certain timeout.
+	 */
+	clear_bit(USE_DEGR_WFC_T, &mdev->flags);
+	if (mdev->state.role != R_PRIMARY &&
+	     drbd_md_test_flag(mdev->ldev, MDF_PRIMARY_IND) &&
+	    !drbd_md_test_flag(mdev->ldev, MDF_CONNECTED_IND))
+		set_bit(USE_DEGR_WFC_T, &mdev->flags);
+
+	dd = drbd_determin_dev_size(mdev);
+	if (dd == dev_size_error) {
+		retcode = ERR_NOMEM_BITMAP;
+		goto force_diskless_dec;
+	} else if (dd == grew)
+		set_bit(RESYNC_AFTER_NEG, &mdev->flags);
+
+	if (drbd_md_test_flag(mdev->ldev, MDF_FULL_SYNC)) {
+		dev_info(DEV, "Assuming that all blocks are out of sync "
+		     "(aka FullSync)\n");
+		if (drbd_bitmap_io(mdev, &drbd_bmio_set_n_write, "set_n_write from attaching")) {
+			retcode = ERR_IO_MD_DISK;
+			goto force_diskless_dec;
+		}
+	} else {
+		if (drbd_bitmap_io(mdev, &drbd_bm_read, "read from attaching") < 0) {
+			retcode = ERR_IO_MD_DISK;
+			goto force_diskless_dec;
+		}
+	}
+
+	if (cp_discovered) {
+		drbd_al_apply_to_bm(mdev);
+		drbd_al_to_on_disk_bm(mdev);
+	}
+
+	spin_lock_irq(&mdev->req_lock);
+	os = mdev->state;
+	ns.i = os.i;
+	/* If MDF_CONSISTENT is not set go into inconsistent state,
+	   otherwise investigate MDF_WasUpToDate...
+	   If MDF_WAS_UP_TO_DATE is not set go into D_OUTDATED disk state,
+	   otherwise into D_CONSISTENT state.
+	*/
+	if (drbd_md_test_flag(mdev->ldev, MDF_CONSISTENT)) {
+		if (drbd_md_test_flag(mdev->ldev, MDF_WAS_UP_TO_DATE))
+			ns.disk = D_CONSISTENT;
+		else
+			ns.disk = D_OUTDATED;
+	} else {
+		ns.disk = D_INCONSISTENT;
+	}
+
+	if (drbd_md_test_flag(mdev->ldev, MDF_PEER_OUT_DATED))
+		ns.pdsk = D_OUTDATED;
+
+	if ( ns.disk == D_CONSISTENT &&
+	    (ns.pdsk == D_OUTDATED || mdev->ldev->dc.fencing == FP_DONT_CARE))
+		ns.disk = D_UP_TO_DATE;
+
+	/* All tests on MDF_PRIMARY_IND, MDF_CONNECTED_IND,
+	   MDF_CONSISTENT and MDF_WAS_UP_TO_DATE must happen before
+	   this point, because drbd_request_state() modifies these
+	   flags. */
+
+	/* In case we are C_CONNECTED postpone any decision on the new disk
+	   state after the negotiation phase. */
+	if (mdev->state.conn == C_CONNECTED) {
+		mdev->new_state_tmp.i = ns.i;
+		ns.i = os.i;
+		ns.disk = D_NEGOTIATING;
+	}
+
+	rv = _drbd_set_state(mdev, ns, CS_VERBOSE, NULL);
+	ns = mdev->state;
+	spin_unlock_irq(&mdev->req_lock);
+
+	if (rv < SS_SUCCESS)
+		goto force_diskless_dec;
+
+	if (mdev->state.role == R_PRIMARY)
+		mdev->ldev->md.uuid[UI_CURRENT] |=  (u64)1;
+	else
+		mdev->ldev->md.uuid[UI_CURRENT] &= ~(u64)1;
+
+	drbd_md_mark_dirty(mdev);
+	drbd_md_sync(mdev);
+
+	kobject_uevent(&disk_to_dev(mdev->vdisk)->kobj, KOBJ_CHANGE);
+	put_ldev(mdev);
+	reply->ret_code = retcode;
+	drbd_reconfig_done(mdev);
+	return 0;
+
+ force_diskless_dec:
+	put_ldev(mdev);
+ force_diskless:
+	drbd_force_state(mdev, NS(disk, D_DISKLESS));
+	drbd_md_sync(mdev);
+ release_bdev2_fail:
+	if (nbc)
+		bd_release(nbc->md_bdev);
+ release_bdev_fail:
+	if (nbc)
+		bd_release(nbc->backing_bdev);
+ fail:
+	if (nbc) {
+		if (nbc->lo_file)
+			fput(nbc->lo_file);
+		if (nbc->md_file)
+			fput(nbc->md_file);
+		kfree(nbc);
+	}
+	lc_destroy(resync_lru);
+
+	reply->ret_code = retcode;
+	drbd_reconfig_done(mdev);
+	return 0;
+}
+
+static int drbd_nl_detach(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			  struct drbd_nl_cfg_reply *reply)
+{
+	reply->ret_code = drbd_request_state(mdev, NS(disk, D_DISKLESS));
+	return 0;
+}
+
+static int drbd_nl_net_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			    struct drbd_nl_cfg_reply *reply)
+{
+	int i, ns;
+	enum drbd_ret_codes retcode;
+	struct net_conf *new_conf = NULL;
+	struct crypto_hash *tfm = NULL;
+	struct crypto_hash *integrity_w_tfm = NULL;
+	struct crypto_hash *integrity_r_tfm = NULL;
+	struct hlist_head *new_tl_hash = NULL;
+	struct hlist_head *new_ee_hash = NULL;
+	struct drbd_conf *odev;
+	char hmac_name[CRYPTO_MAX_ALG_NAME];
+	void *int_dig_out = NULL;
+	void *int_dig_in = NULL;
+	void *int_dig_vv = NULL;
+	struct sockaddr *new_my_addr, *new_peer_addr, *taken_addr;
+
+	drbd_reconfig_start(mdev);
+
+	if (mdev->state.conn > C_STANDALONE) {
+		retcode = ERR_NET_CONFIGURED;
+		goto fail;
+	}
+
+	/* allocation not in the IO path, cqueue thread context */
+	new_conf = kmalloc(sizeof(struct net_conf), GFP_KERNEL);
+	if (!new_conf) {
+		retcode = ERR_NOMEM;
+		goto fail;
+	}
+
+	memset(new_conf, 0, sizeof(struct net_conf));
+	new_conf->timeout	   = DRBD_TIMEOUT_DEF;
+	new_conf->try_connect_int  = DRBD_CONNECT_INT_DEF;
+	new_conf->ping_int	   = DRBD_PING_INT_DEF;
+	new_conf->max_epoch_size   = DRBD_MAX_EPOCH_SIZE_DEF;
+	new_conf->max_buffers	   = DRBD_MAX_BUFFERS_DEF;
+	new_conf->unplug_watermark = DRBD_UNPLUG_WATERMARK_DEF;
+	new_conf->sndbuf_size	   = DRBD_SNDBUF_SIZE_DEF;
+	new_conf->rcvbuf_size	   = DRBD_RCVBUF_SIZE_DEF;
+	new_conf->ko_count	   = DRBD_KO_COUNT_DEF;
+	new_conf->after_sb_0p	   = DRBD_AFTER_SB_0P_DEF;
+	new_conf->after_sb_1p	   = DRBD_AFTER_SB_1P_DEF;
+	new_conf->after_sb_2p	   = DRBD_AFTER_SB_2P_DEF;
+	new_conf->want_lose	   = 0;
+	new_conf->two_primaries    = 0;
+	new_conf->wire_protocol    = DRBD_PROT_C;
+	new_conf->ping_timeo	   = DRBD_PING_TIMEO_DEF;
+	new_conf->rr_conflict	   = DRBD_RR_CONFLICT_DEF;
+
+	if (!net_conf_from_tags(mdev, nlp->tag_list, new_conf)) {
+		retcode = ERR_MANDATORY_TAG;
+		goto fail;
+	}
+
+	if (new_conf->two_primaries
+	    && (new_conf->wire_protocol != DRBD_PROT_C)) {
+		retcode = ERR_NOT_PROTO_C;
+		goto fail;
+	};
+
+	if (mdev->state.role == R_PRIMARY && new_conf->want_lose) {
+		retcode = ERR_DISCARD;
+		goto fail;
+	}
+
+	retcode = NO_ERROR;
+
+	new_my_addr = (struct sockaddr *)&new_conf->my_addr;
+	new_peer_addr = (struct sockaddr *)&new_conf->peer_addr;
+	for (i = 0; i < minor_count; i++) {
+		odev = minor_to_mdev(i);
+		if (!odev || odev == mdev)
+			continue;
+		if (get_net_conf(odev)) {
+			taken_addr = (struct sockaddr *)&odev->net_conf->my_addr;
+			if (new_conf->my_addr_len == odev->net_conf->my_addr_len &&
+			    !memcmp(new_my_addr, taken_addr, new_conf->my_addr_len))
+				retcode = ERR_LOCAL_ADDR;
+
+			taken_addr = (struct sockaddr *)&odev->net_conf->peer_addr;
+			if (new_conf->peer_addr_len == odev->net_conf->peer_addr_len &&
+			    !memcmp(new_peer_addr, taken_addr, new_conf->peer_addr_len))
+				retcode = ERR_PEER_ADDR;
+
+			put_net_conf(odev);
+			if (retcode != NO_ERROR)
+				goto fail;
+		}
+	}
+
+	if (new_conf->cram_hmac_alg[0] != 0) {
+		snprintf(hmac_name, CRYPTO_MAX_ALG_NAME, "hmac(%s)",
+			new_conf->cram_hmac_alg);
+		tfm = crypto_alloc_hash(hmac_name, 0, CRYPTO_ALG_ASYNC);
+		if (IS_ERR(tfm)) {
+			tfm = NULL;
+			retcode = ERR_AUTH_ALG;
+			goto fail;
+		}
+
+		if (crypto_tfm_alg_type(crypto_hash_tfm(tfm))
+						!= CRYPTO_ALG_TYPE_HASH) {
+			retcode = ERR_AUTH_ALG_ND;
+			goto fail;
+		}
+	}
+
+	if (new_conf->integrity_alg[0]) {
+		integrity_w_tfm = crypto_alloc_hash(new_conf->integrity_alg, 0, CRYPTO_ALG_ASYNC);
+		if (IS_ERR(integrity_w_tfm)) {
+			integrity_w_tfm = NULL;
+			retcode=ERR_INTEGRITY_ALG;
+			goto fail;
+		}
+
+		if (!drbd_crypto_is_hash(crypto_hash_tfm(integrity_w_tfm))) {
+			retcode=ERR_INTEGRITY_ALG_ND;
+			goto fail;
+		}
+
+		integrity_r_tfm = crypto_alloc_hash(new_conf->integrity_alg, 0, CRYPTO_ALG_ASYNC);
+		if (IS_ERR(integrity_r_tfm)) {
+			integrity_r_tfm = NULL;
+			retcode=ERR_INTEGRITY_ALG;
+			goto fail;
+		}
+	}
+
+	ns = new_conf->max_epoch_size/8;
+	if (mdev->tl_hash_s != ns) {
+		new_tl_hash = kzalloc(ns*sizeof(void *), GFP_KERNEL);
+		if (!new_tl_hash) {
+			retcode = ERR_NOMEM;
+			goto fail;
+		}
+	}
+
+	ns = new_conf->max_buffers/8;
+	if (new_conf->two_primaries && (mdev->ee_hash_s != ns)) {
+		new_ee_hash = kzalloc(ns*sizeof(void *), GFP_KERNEL);
+		if (!new_ee_hash) {
+			retcode = ERR_NOMEM;
+			goto fail;
+		}
+	}
+
+	((char *)new_conf->shared_secret)[SHARED_SECRET_MAX-1] = 0;
+
+	if (integrity_w_tfm) {
+		i = crypto_hash_digestsize(integrity_w_tfm);
+		int_dig_out = kmalloc(i, GFP_KERNEL);
+		if (!int_dig_out) {
+			retcode = ERR_NOMEM;
+			goto fail;
+		}
+		int_dig_in = kmalloc(i, GFP_KERNEL);
+		if (!int_dig_in) {
+			retcode = ERR_NOMEM;
+			goto fail;
+		}
+		int_dig_vv = kmalloc(i, GFP_KERNEL);
+		if (!int_dig_vv) {
+			retcode = ERR_NOMEM;
+			goto fail;
+		}
+	}
+
+	if (!mdev->bitmap) {
+		if(drbd_bm_init(mdev)) {
+			retcode = ERR_NOMEM;
+			goto fail;
+		}
+	}
+
+	spin_lock_irq(&mdev->req_lock);
+	if (mdev->net_conf != NULL) {
+		retcode = ERR_NET_CONFIGURED;
+		spin_unlock_irq(&mdev->req_lock);
+		goto fail;
+	}
+	mdev->net_conf = new_conf;
+
+	mdev->send_cnt = 0;
+	mdev->recv_cnt = 0;
+
+	if (new_tl_hash) {
+		kfree(mdev->tl_hash);
+		mdev->tl_hash_s = mdev->net_conf->max_epoch_size/8;
+		mdev->tl_hash = new_tl_hash;
+	}
+
+	if (new_ee_hash) {
+		kfree(mdev->ee_hash);
+		mdev->ee_hash_s = mdev->net_conf->max_buffers/8;
+		mdev->ee_hash = new_ee_hash;
+	}
+
+	crypto_free_hash(mdev->cram_hmac_tfm);
+	mdev->cram_hmac_tfm = tfm;
+
+	crypto_free_hash(mdev->integrity_w_tfm);
+	mdev->integrity_w_tfm = integrity_w_tfm;
+
+	crypto_free_hash(mdev->integrity_r_tfm);
+	mdev->integrity_r_tfm = integrity_r_tfm;
+
+	kfree(mdev->int_dig_out);
+	kfree(mdev->int_dig_in);
+	kfree(mdev->int_dig_vv);
+	mdev->int_dig_out=int_dig_out;
+	mdev->int_dig_in=int_dig_in;
+	mdev->int_dig_vv=int_dig_vv;
+	spin_unlock_irq(&mdev->req_lock);
+
+	retcode = _drbd_request_state(mdev, NS(conn, C_UNCONNECTED), CS_VERBOSE);
+
+	kobject_uevent(&disk_to_dev(mdev->vdisk)->kobj, KOBJ_CHANGE);
+	reply->ret_code = retcode;
+	drbd_reconfig_done(mdev);
+	return 0;
+
+fail:
+	kfree(int_dig_out);
+	kfree(int_dig_in);
+	kfree(int_dig_vv);
+	crypto_free_hash(tfm);
+	crypto_free_hash(integrity_w_tfm);
+	crypto_free_hash(integrity_r_tfm);
+	kfree(new_tl_hash);
+	kfree(new_ee_hash);
+	kfree(new_conf);
+
+	reply->ret_code = retcode;
+	drbd_reconfig_done(mdev);
+	return 0;
+}
+
+static int drbd_nl_disconnect(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			      struct drbd_nl_cfg_reply *reply)
+{
+	int retcode;
+
+	retcode = _drbd_request_state(mdev, NS(conn, C_DISCONNECTING), CS_ORDERED);
+
+	if (retcode == SS_NOTHING_TO_DO)
+		goto done;
+	else if (retcode == SS_ALREADY_STANDALONE)
+		goto done;
+	else if (retcode == SS_PRIMARY_NOP) {
+		/* Our statche checking code wants to see the peer outdated. */
+		retcode = drbd_request_state(mdev, NS2(conn, C_DISCONNECTING,
+						      pdsk, D_OUTDATED));
+	} else if (retcode == SS_CW_FAILED_BY_PEER) {
+		/* The peer probably wants to see us outdated. */
+		retcode = _drbd_request_state(mdev, NS2(conn, C_DISCONNECTING,
+							disk, D_OUTDATED),
+					      CS_ORDERED);
+		if (retcode == SS_IS_DISKLESS || retcode == SS_LOWER_THAN_OUTDATED) {
+			drbd_force_state(mdev, NS(conn, C_DISCONNECTING));
+			retcode = SS_SUCCESS;
+		}
+	}
+
+	if (retcode < SS_SUCCESS)
+		goto fail;
+
+	if (wait_event_interruptible(mdev->state_wait,
+				     mdev->state.conn != C_DISCONNECTING)) {
+		/* Do not test for mdev->state.conn == C_STANDALONE, since
+		   someone else might connect us in the mean time! */
+		retcode = ERR_INTR;
+		goto fail;
+	}
+
+ done:
+	retcode = NO_ERROR;
+ fail:
+	drbd_md_sync(mdev);
+	reply->ret_code = retcode;
+	return 0;
+}
+
+void resync_after_online_grow(struct drbd_conf *mdev)
+{
+	int iass; /* I am sync source */
+
+	dev_info(DEV, "Resync of new storage after online grow\n");
+	if (mdev->state.role != mdev->state.peer)
+		iass = (mdev->state.role == R_PRIMARY);
+	else
+		iass = test_bit(DISCARD_CONCURRENT, &mdev->flags);
+
+	if (iass)
+		drbd_start_resync(mdev, C_SYNC_SOURCE);
+	else
+		_drbd_request_state(mdev, NS(conn, C_WF_SYNC_UUID), CS_VERBOSE + CS_SERIALIZE);
+}
+
+static int drbd_nl_resize(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			  struct drbd_nl_cfg_reply *reply)
+{
+	struct resize rs;
+	int retcode = NO_ERROR;
+	int ldsc = 0; /* local disk size changed */
+	enum determine_dev_size dd;
+
+	memset(&rs, 0, sizeof(struct resize));
+	if (!resize_from_tags(mdev, nlp->tag_list, &rs)) {
+		retcode = ERR_MANDATORY_TAG;
+		goto fail;
+	}
+
+	if (mdev->state.conn > C_CONNECTED) {
+		retcode = ERR_RESIZE_RESYNC;
+		goto fail;
+	}
+
+	if (mdev->state.role == R_SECONDARY &&
+	    mdev->state.peer == R_SECONDARY) {
+		retcode = ERR_NO_PRIMARY;
+		goto fail;
+	}
+
+	if (!get_ldev(mdev)) {
+		retcode = ERR_NO_DISK;
+		goto fail;
+	}
+
+	if (mdev->ldev->known_size != drbd_get_capacity(mdev->ldev->backing_bdev)) {
+		mdev->ldev->known_size = drbd_get_capacity(mdev->ldev->backing_bdev);
+		ldsc = 1;
+	}
+
+	mdev->ldev->dc.disk_size = (sector_t)rs.resize_size;
+	dd = drbd_determin_dev_size(mdev);
+	drbd_md_sync(mdev);
+	put_ldev(mdev);
+	if (dd == dev_size_error) {
+		retcode = ERR_NOMEM_BITMAP;
+		goto fail;
+	}
+
+	if (mdev->state.conn == C_CONNECTED && (dd != unchanged || ldsc)) {
+		if (dd == grew)
+			set_bit(RESIZE_PENDING, &mdev->flags);
+
+		drbd_send_uuids(mdev);
+		drbd_send_sizes(mdev, 1);
+	}
+
+ fail:
+	reply->ret_code = retcode;
+	return 0;
+}
+
+static int drbd_nl_syncer_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			       struct drbd_nl_cfg_reply *reply)
+{
+	int retcode = NO_ERROR;
+	int err;
+	int ovr; /* online verify running */
+	int rsr; /* re-sync running */
+	struct crypto_hash *verify_tfm = NULL;
+	struct crypto_hash *csums_tfm = NULL;
+	struct syncer_conf sc;
+	cpumask_var_t new_cpu_mask;
+
+	if (!zalloc_cpumask_var(&new_cpu_mask, GFP_KERNEL)) {
+		retcode = ERR_NOMEM;
+		goto fail;
+	}
+
+	if (nlp->flags & DRBD_NL_SET_DEFAULTS) {
+		memset(&sc, 0, sizeof(struct syncer_conf));
+		sc.rate       = DRBD_RATE_DEF;
+		sc.after      = DRBD_AFTER_DEF;
+		sc.al_extents = DRBD_AL_EXTENTS_DEF;
+	} else
+		memcpy(&sc, &mdev->sync_conf, sizeof(struct syncer_conf));
+
+	if (!syncer_conf_from_tags(mdev, nlp->tag_list, &sc)) {
+		retcode = ERR_MANDATORY_TAG;
+		goto fail;
+	}
+
+	/* re-sync running */
+	rsr = (	mdev->state.conn == C_SYNC_SOURCE ||
+		mdev->state.conn == C_SYNC_TARGET ||
+		mdev->state.conn == C_PAUSED_SYNC_S ||
+		mdev->state.conn == C_PAUSED_SYNC_T );
+
+	if (rsr && strcmp(sc.csums_alg, mdev->sync_conf.csums_alg)) {
+		retcode = ERR_CSUMS_RESYNC_RUNNING;
+		goto fail;
+	}
+
+	if (!rsr && sc.csums_alg[0]) {
+		csums_tfm = crypto_alloc_hash(sc.csums_alg, 0, CRYPTO_ALG_ASYNC);
+		if (IS_ERR(csums_tfm)) {
+			csums_tfm = NULL;
+			retcode = ERR_CSUMS_ALG;
+			goto fail;
+		}
+
+		if (!drbd_crypto_is_hash(crypto_hash_tfm(csums_tfm))) {
+			retcode = ERR_CSUMS_ALG_ND;
+			goto fail;
+		}
+	}
+
+	/* online verify running */
+	ovr = (mdev->state.conn == C_VERIFY_S || mdev->state.conn == C_VERIFY_T);
+
+	if (ovr) {
+		if (strcmp(sc.verify_alg, mdev->sync_conf.verify_alg)) {
+			retcode = ERR_VERIFY_RUNNING;
+			goto fail;
+		}
+	}
+
+	if (!ovr && sc.verify_alg[0]) {
+		verify_tfm = crypto_alloc_hash(sc.verify_alg, 0, CRYPTO_ALG_ASYNC);
+		if (IS_ERR(verify_tfm)) {
+			verify_tfm = NULL;
+			retcode = ERR_VERIFY_ALG;
+			goto fail;
+		}
+
+		if (!drbd_crypto_is_hash(crypto_hash_tfm(verify_tfm))) {
+			retcode = ERR_VERIFY_ALG_ND;
+			goto fail;
+		}
+	}
+
+	/* silently ignore cpu mask on UP kernel */
+	if (nr_cpu_ids > 1 && sc.cpu_mask[0] != 0) {
+		err = __bitmap_parse(sc.cpu_mask, 32, 0,
+				cpumask_bits(new_cpu_mask), nr_cpu_ids);
+		if (err) {
+			dev_warn(DEV, "__bitmap_parse() failed with %d\n", err);
+			retcode = ERR_CPU_MASK_PARSE;
+			goto fail;
+		}
+	}
+
+	ERR_IF (sc.rate < 1) sc.rate = 1;
+	ERR_IF (sc.al_extents < 7) sc.al_extents = 127; /* arbitrary minimum */
+#define AL_MAX ((MD_AL_MAX_SIZE-1) * AL_EXTENTS_PT)
+	if (sc.al_extents > AL_MAX) {
+		dev_err(DEV, "sc.al_extents > %d\n", AL_MAX);
+		sc.al_extents = AL_MAX;
+	}
+#undef AL_MAX
+
+	/* most sanity checks done, try to assign the new sync-after
+	 * dependency.  need to hold the global lock in there,
+	 * to avoid a race in the dependency loop check. */
+	retcode = drbd_alter_sa(mdev, sc.after);
+	if (retcode != NO_ERROR)
+		goto fail;
+
+	/* ok, assign the rest of it as well.
+	 * lock against receive_SyncParam() */
+	spin_lock(&mdev->peer_seq_lock);
+	mdev->sync_conf = sc;
+
+	if (!rsr) {
+		crypto_free_hash(mdev->csums_tfm);
+		mdev->csums_tfm = csums_tfm;
+		csums_tfm = NULL;
+	}
+
+	if (!ovr) {
+		crypto_free_hash(mdev->verify_tfm);
+		mdev->verify_tfm = verify_tfm;
+		verify_tfm = NULL;
+	}
+	spin_unlock(&mdev->peer_seq_lock);
+
+	if (get_ldev(mdev)) {
+		wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
+		drbd_al_shrink(mdev);
+		err = drbd_check_al_size(mdev);
+		lc_unlock(mdev->act_log);
+		wake_up(&mdev->al_wait);
+
+		put_ldev(mdev);
+		drbd_md_sync(mdev);
+
+		if (err) {
+			retcode = ERR_NOMEM;
+			goto fail;
+		}
+	}
+
+	if (mdev->state.conn >= C_CONNECTED)
+		drbd_send_sync_param(mdev, &sc);
+
+	if (!cpumask_equal(mdev->cpu_mask, new_cpu_mask)) {
+		cpumask_copy(mdev->cpu_mask, new_cpu_mask);
+		drbd_calc_cpu_mask(mdev);
+		mdev->receiver.reset_cpu_mask = 1;
+		mdev->asender.reset_cpu_mask = 1;
+		mdev->worker.reset_cpu_mask = 1;
+	}
+
+	kobject_uevent(&disk_to_dev(mdev->vdisk)->kobj, KOBJ_CHANGE);
+fail:
+	free_cpumask_var(new_cpu_mask);
+	crypto_free_hash(csums_tfm);
+	crypto_free_hash(verify_tfm);
+	reply->ret_code = retcode;
+	return 0;
+}
+
+static int drbd_nl_invalidate(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			      struct drbd_nl_cfg_reply *reply)
+{
+	int retcode;
+
+	retcode = _drbd_request_state(mdev, NS(conn, C_STARTING_SYNC_T), CS_ORDERED);
+
+	if (retcode < SS_SUCCESS && retcode != SS_NEED_CONNECTION)
+		retcode = drbd_request_state(mdev, NS(conn, C_STARTING_SYNC_T));
+
+	while (retcode == SS_NEED_CONNECTION) {
+		spin_lock_irq(&mdev->req_lock);
+		if (mdev->state.conn < C_CONNECTED)
+			retcode = _drbd_set_state(_NS(mdev, disk, D_INCONSISTENT), CS_VERBOSE, NULL);
+		spin_unlock_irq(&mdev->req_lock);
+
+		if (retcode != SS_NEED_CONNECTION)
+			break;
+
+		retcode = drbd_request_state(mdev, NS(conn, C_STARTING_SYNC_T));
+	}
+
+	reply->ret_code = retcode;
+	return 0;
+}
+
+static int drbd_nl_invalidate_peer(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+				   struct drbd_nl_cfg_reply *reply)
+{
+
+	reply->ret_code = drbd_request_state(mdev, NS(conn, C_STARTING_SYNC_S));
+
+	return 0;
+}
+
+static int drbd_nl_pause_sync(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			      struct drbd_nl_cfg_reply *reply)
+{
+	int retcode = NO_ERROR;
+
+	if (drbd_request_state(mdev, NS(user_isp, 1)) == SS_NOTHING_TO_DO)
+		retcode = ERR_PAUSE_IS_SET;
+
+	reply->ret_code = retcode;
+	return 0;
+}
+
+static int drbd_nl_resume_sync(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			       struct drbd_nl_cfg_reply *reply)
+{
+	int retcode = NO_ERROR;
+
+	if (drbd_request_state(mdev, NS(user_isp, 0)) == SS_NOTHING_TO_DO)
+		retcode = ERR_PAUSE_IS_CLEAR;
+
+	reply->ret_code = retcode;
+	return 0;
+}
+
+static int drbd_nl_suspend_io(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			      struct drbd_nl_cfg_reply *reply)
+{
+	reply->ret_code = drbd_request_state(mdev, NS(susp, 1));
+
+	return 0;
+}
+
+static int drbd_nl_resume_io(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			     struct drbd_nl_cfg_reply *reply)
+{
+	reply->ret_code = drbd_request_state(mdev, NS(susp, 0));
+	return 0;
+}
+
+static int drbd_nl_outdate(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			   struct drbd_nl_cfg_reply *reply)
+{
+	reply->ret_code = drbd_request_state(mdev, NS(disk, D_OUTDATED));
+	return 0;
+}
+
+static int drbd_nl_get_config(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			   struct drbd_nl_cfg_reply *reply)
+{
+	unsigned short *tl;
+
+	tl = reply->tag_list;
+
+	if (get_ldev(mdev)) {
+		tl = disk_conf_to_tags(mdev, &mdev->ldev->dc, tl);
+		put_ldev(mdev);
+	}
+
+	if (get_net_conf(mdev)) {
+		tl = net_conf_to_tags(mdev, mdev->net_conf, tl);
+		put_net_conf(mdev);
+	}
+	tl = syncer_conf_to_tags(mdev, &mdev->sync_conf, tl);
+
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	return (int)((char *)tl - (char *)reply->tag_list);
+}
+
+static int drbd_nl_get_state(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			     struct drbd_nl_cfg_reply *reply)
+{
+	unsigned short *tl = reply->tag_list;
+	union drbd_state s = mdev->state;
+	unsigned long rs_left;
+	unsigned int res;
+
+	tl = get_state_to_tags(mdev, (struct get_state *)&s, tl);
+
+	/* no local ref, no bitmap, no syncer progress. */
+	if (s.conn >= C_SYNC_SOURCE && s.conn <= C_PAUSED_SYNC_T) {
+		if (get_ldev(mdev)) {
+			drbd_get_syncer_progress(mdev, &rs_left, &res);
+			tl = tl_add_int(tl, T_sync_progress, &res);
+			put_ldev(mdev);
+		}
+	}
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	return (int)((char *)tl - (char *)reply->tag_list);
+}
+
+static int drbd_nl_get_uuids(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			     struct drbd_nl_cfg_reply *reply)
+{
+	unsigned short *tl;
+
+	tl = reply->tag_list;
+
+	if (get_ldev(mdev)) {
+		tl = tl_add_blob(tl, T_uuids, mdev->ldev->md.uuid, UI_SIZE*sizeof(u64));
+		tl = tl_add_int(tl, T_uuids_flags, &mdev->ldev->md.flags);
+		put_ldev(mdev);
+	}
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	return (int)((char *)tl - (char *)reply->tag_list);
+}
+
+/**
+ * drbd_nl_get_timeout_flag() - Used by drbdsetup to find out which timeout value to use
+ * @mdev:	DRBD device.
+ * @nlp:	Netlink/connector packet from drbdsetup
+ * @reply:	Reply packet for drbdsetup
+ */
+static int drbd_nl_get_timeout_flag(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+				    struct drbd_nl_cfg_reply *reply)
+{
+	unsigned short *tl;
+	char rv;
+
+	tl = reply->tag_list;
+
+	rv = mdev->state.pdsk == D_OUTDATED        ? UT_PEER_OUTDATED :
+	  test_bit(USE_DEGR_WFC_T, &mdev->flags) ? UT_DEGRADED : UT_DEFAULT;
+
+	tl = tl_add_blob(tl, T_use_degraded, &rv, sizeof(rv));
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	return (int)((char *)tl - (char *)reply->tag_list);
+}
+
+static int drbd_nl_start_ov(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+				    struct drbd_nl_cfg_reply *reply)
+{
+	/* default to resume from last known position, if possible */
+	struct start_ov args =
+		{ .start_sector = mdev->ov_start_sector };
+
+	if (!start_ov_from_tags(mdev, nlp->tag_list, &args)) {
+		reply->ret_code = ERR_MANDATORY_TAG;
+		return 0;
+	}
+	/* w_make_ov_request expects position to be aligned */
+	mdev->ov_start_sector = args.start_sector & ~BM_SECT_PER_BIT;
+	reply->ret_code = drbd_request_state(mdev,NS(conn,C_VERIFY_S));
+	return 0;
+}
+
+
+static int drbd_nl_new_c_uuid(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
+			      struct drbd_nl_cfg_reply *reply)
+{
+	int retcode = NO_ERROR;
+	int skip_initial_sync = 0;
+	int err;
+
+	struct new_c_uuid args;
+
+	memset(&args, 0, sizeof(struct new_c_uuid));
+	if (!new_c_uuid_from_tags(mdev, nlp->tag_list, &args)) {
+		reply->ret_code = ERR_MANDATORY_TAG;
+		return 0;
+	}
+
+	mutex_lock(&mdev->state_mutex); /* Protects us against serialized state changes. */
+
+	if (!get_ldev(mdev)) {
+		retcode = ERR_NO_DISK;
+		goto out;
+	}
+
+	/* this is "skip initial sync", assume to be clean */
+	if (mdev->state.conn == C_CONNECTED && mdev->agreed_pro_version >= 90 &&
+	    mdev->ldev->md.uuid[UI_CURRENT] == UUID_JUST_CREATED && args.clear_bm) {
+		dev_info(DEV, "Preparing to skip initial sync\n");
+		skip_initial_sync = 1;
+	} else if (mdev->state.conn != C_STANDALONE) {
+		retcode = ERR_CONNECTED;
+		goto out_dec;
+	}
+
+	drbd_uuid_set(mdev, UI_BITMAP, 0); /* Rotate UI_BITMAP to History 1, etc... */
+	drbd_uuid_new_current(mdev); /* New current, previous to UI_BITMAP */
+
+	if (args.clear_bm) {
+		err = drbd_bitmap_io(mdev, &drbd_bmio_clear_n_write, "clear_n_write from new_c_uuid");
+		if (err) {
+			dev_err(DEV, "Writing bitmap failed with %d\n",err);
+			retcode = ERR_IO_MD_DISK;
+		}
+		if (skip_initial_sync) {
+			drbd_send_uuids_skip_initial_sync(mdev);
+			_drbd_uuid_set(mdev, UI_BITMAP, 0);
+			spin_lock_irq(&mdev->req_lock);
+			_drbd_set_state(_NS2(mdev, disk, D_UP_TO_DATE, pdsk, D_UP_TO_DATE),
+					CS_VERBOSE, NULL);
+			spin_unlock_irq(&mdev->req_lock);
+		}
+	}
+
+	drbd_md_sync(mdev);
+out_dec:
+	put_ldev(mdev);
+out:
+	mutex_unlock(&mdev->state_mutex);
+
+	reply->ret_code = retcode;
+	return 0;
+}
+
+static struct drbd_conf *ensure_mdev(struct drbd_nl_cfg_req *nlp)
+{
+	struct drbd_conf *mdev;
+
+	if (nlp->drbd_minor >= minor_count)
+		return NULL;
+
+	mdev = minor_to_mdev(nlp->drbd_minor);
+
+	if (!mdev && (nlp->flags & DRBD_NL_CREATE_DEVICE)) {
+		struct gendisk *disk = NULL;
+		mdev = drbd_new_device(nlp->drbd_minor);
+
+		spin_lock_irq(&drbd_pp_lock);
+		if (minor_table[nlp->drbd_minor] == NULL) {
+			minor_table[nlp->drbd_minor] = mdev;
+			disk = mdev->vdisk;
+			mdev = NULL;
+		} /* else: we lost the race */
+		spin_unlock_irq(&drbd_pp_lock);
+
+		if (disk) /* we won the race above */
+			/* in case we ever add a drbd_delete_device(),
+			 * don't forget the del_gendisk! */
+			add_disk(disk);
+		else /* we lost the race above */
+			drbd_free_mdev(mdev);
+
+		mdev = minor_to_mdev(nlp->drbd_minor);
+	}
+
+	return mdev;
+}
+
+struct cn_handler_struct {
+	int (*function)(struct drbd_conf *,
+			 struct drbd_nl_cfg_req *,
+			 struct drbd_nl_cfg_reply *);
+	int reply_body_size;
+};
+
+static struct cn_handler_struct cnd_table[] = {
+	[ P_primary ]		= { &drbd_nl_primary,		0 },
+	[ P_secondary ]		= { &drbd_nl_secondary,		0 },
+	[ P_disk_conf ]		= { &drbd_nl_disk_conf,		0 },
+	[ P_detach ]		= { &drbd_nl_detach,		0 },
+	[ P_net_conf ]		= { &drbd_nl_net_conf,		0 },
+	[ P_disconnect ]	= { &drbd_nl_disconnect,	0 },
+	[ P_resize ]		= { &drbd_nl_resize,		0 },
+	[ P_syncer_conf ]	= { &drbd_nl_syncer_conf,	0 },
+	[ P_invalidate ]	= { &drbd_nl_invalidate,	0 },
+	[ P_invalidate_peer ]	= { &drbd_nl_invalidate_peer,	0 },
+	[ P_pause_sync ]	= { &drbd_nl_pause_sync,	0 },
+	[ P_resume_sync ]	= { &drbd_nl_resume_sync,	0 },
+	[ P_suspend_io ]	= { &drbd_nl_suspend_io,	0 },
+	[ P_resume_io ]		= { &drbd_nl_resume_io,		0 },
+	[ P_outdate ]		= { &drbd_nl_outdate,		0 },
+	[ P_get_config ]	= { &drbd_nl_get_config,
+				    sizeof(struct syncer_conf_tag_len_struct) +
+				    sizeof(struct disk_conf_tag_len_struct) +
+				    sizeof(struct net_conf_tag_len_struct) },
+	[ P_get_state ]		= { &drbd_nl_get_state,
+				    sizeof(struct get_state_tag_len_struct) +
+				    sizeof(struct sync_progress_tag_len_struct)	},
+	[ P_get_uuids ]		= { &drbd_nl_get_uuids,
+				    sizeof(struct get_uuids_tag_len_struct) },
+	[ P_get_timeout_flag ]	= { &drbd_nl_get_timeout_flag,
+				    sizeof(struct get_timeout_flag_tag_len_struct)},
+	[ P_start_ov ]		= { &drbd_nl_start_ov,		0 },
+	[ P_new_c_uuid ]	= { &drbd_nl_new_c_uuid,	0 },
+};
+
+static void drbd_connector_callback(struct cn_msg *req)
+{
+	struct drbd_nl_cfg_req *nlp = (struct drbd_nl_cfg_req *)req->data;
+	struct cn_handler_struct *cm;
+	struct cn_msg *cn_reply;
+	struct drbd_nl_cfg_reply *reply;
+	struct drbd_conf *mdev;
+	int retcode, rr;
+	int reply_size = sizeof(struct cn_msg)
+		+ sizeof(struct drbd_nl_cfg_reply)
+		+ sizeof(short int);
+
+	if (!try_module_get(THIS_MODULE)) {
+		printk(KERN_ERR "drbd: try_module_get() failed!\n");
+		return;
+	}
+
+	mdev = ensure_mdev(nlp);
+	if (!mdev) {
+		retcode = ERR_MINOR_INVALID;
+		goto fail;
+	}
+
+	trace_drbd_netlink(req, 1);
+
+	if (nlp->packet_type >= P_nl_after_last_packet) {
+		retcode = ERR_PACKET_NR;
+		goto fail;
+	}
+
+	cm = cnd_table + nlp->packet_type;
+
+	/* This may happen if packet number is 0: */
+	if (cm->function == NULL) {
+		retcode = ERR_PACKET_NR;
+		goto fail;
+	}
+
+	reply_size += cm->reply_body_size;
+
+	/* allocation not in the IO path, cqueue thread context */
+	cn_reply = kmalloc(reply_size, GFP_KERNEL);
+	if (!cn_reply) {
+		retcode = ERR_NOMEM;
+		goto fail;
+	}
+	reply = (struct drbd_nl_cfg_reply *) cn_reply->data;
+
+	reply->packet_type =
+		cm->reply_body_size ? nlp->packet_type : P_nl_after_last_packet;
+	reply->minor = nlp->drbd_minor;
+	reply->ret_code = NO_ERROR; /* Might by modified by cm->function. */
+	/* reply->tag_list; might be modified by cm->function. */
+
+	rr = cm->function(mdev, nlp, reply);
+
+	cn_reply->id = req->id;
+	cn_reply->seq = req->seq;
+	cn_reply->ack = req->ack  + 1;
+	cn_reply->len = sizeof(struct drbd_nl_cfg_reply) + rr;
+	cn_reply->flags = 0;
+
+	trace_drbd_netlink(cn_reply, 0);
+	rr = cn_netlink_send(cn_reply, CN_IDX_DRBD, GFP_KERNEL);
+	if (rr && rr != -ESRCH)
+		printk(KERN_INFO "drbd: cn_netlink_send()=%d\n", rr);
+
+	kfree(cn_reply);
+	module_put(THIS_MODULE);
+	return;
+ fail:
+	drbd_nl_send_reply(req, retcode);
+	module_put(THIS_MODULE);
+}
+
+static atomic_t drbd_nl_seq = ATOMIC_INIT(2); /* two. */
+
+static unsigned short *
+__tl_add_blob(unsigned short *tl, enum drbd_tags tag, const void *data,
+	unsigned short len, int nul_terminated)
+{
+	unsigned short l = tag_descriptions[tag_number(tag)].max_len;
+	len = (len < l) ? len :  l;
+	put_unaligned(tag, tl++);
+	put_unaligned(len, tl++);
+	memcpy(tl, data, len);
+	tl = (unsigned short*)((char*)tl + len);
+	if (nul_terminated)
+		*((char*)tl - 1) = 0;
+	return tl;
+}
+
+static unsigned short *
+tl_add_blob(unsigned short *tl, enum drbd_tags tag, const void *data, int len)
+{
+	return __tl_add_blob(tl, tag, data, len, 0);
+}
+
+static unsigned short *
+tl_add_str(unsigned short *tl, enum drbd_tags tag, const char *str)
+{
+	return __tl_add_blob(tl, tag, str, strlen(str)+1, 0);
+}
+
+static unsigned short *
+tl_add_int(unsigned short *tl, enum drbd_tags tag, const void *val)
+{
+	put_unaligned(tag, tl++);
+	switch(tag_type(tag)) {
+	case TT_INTEGER:
+		put_unaligned(sizeof(int), tl++);
+		put_unaligned(*(int *)val, (int *)tl);
+		tl = (unsigned short*)((char*)tl+sizeof(int));
+		break;
+	case TT_INT64:
+		put_unaligned(sizeof(u64), tl++);
+		put_unaligned(*(u64 *)val, (u64 *)tl);
+		tl = (unsigned short*)((char*)tl+sizeof(u64));
+		break;
+	default:
+		/* someone did something stupid. */
+		;
+	}
+	return tl;
+}
+
+void drbd_bcast_state(struct drbd_conf *mdev, union drbd_state state)
+{
+	char buffer[sizeof(struct cn_msg)+
+		    sizeof(struct drbd_nl_cfg_reply)+
+		    sizeof(struct get_state_tag_len_struct)+
+		    sizeof(short int)];
+	struct cn_msg *cn_reply = (struct cn_msg *) buffer;
+	struct drbd_nl_cfg_reply *reply =
+		(struct drbd_nl_cfg_reply *)cn_reply->data;
+	unsigned short *tl = reply->tag_list;
+
+	/* dev_warn(DEV, "drbd_bcast_state() got called\n"); */
+
+	tl = get_state_to_tags(mdev, (struct get_state *)&state, tl);
+
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	cn_reply->id.idx = CN_IDX_DRBD;
+	cn_reply->id.val = CN_VAL_DRBD;
+
+	cn_reply->seq = atomic_add_return(1, &drbd_nl_seq);
+	cn_reply->ack = 0; /* not used here. */
+	cn_reply->len = sizeof(struct drbd_nl_cfg_reply) +
+		(int)((char *)tl - (char *)reply->tag_list);
+	cn_reply->flags = 0;
+
+	reply->packet_type = P_get_state;
+	reply->minor = mdev_to_minor(mdev);
+	reply->ret_code = NO_ERROR;
+
+	trace_drbd_netlink(cn_reply, 0);
+	cn_netlink_send(cn_reply, CN_IDX_DRBD, GFP_NOIO);
+}
+
+void drbd_bcast_ev_helper(struct drbd_conf *mdev, char *helper_name)
+{
+	char buffer[sizeof(struct cn_msg)+
+		    sizeof(struct drbd_nl_cfg_reply)+
+		    sizeof(struct call_helper_tag_len_struct)+
+		    sizeof(short int)];
+	struct cn_msg *cn_reply = (struct cn_msg *) buffer;
+	struct drbd_nl_cfg_reply *reply =
+		(struct drbd_nl_cfg_reply *)cn_reply->data;
+	unsigned short *tl = reply->tag_list;
+
+	/* dev_warn(DEV, "drbd_bcast_state() got called\n"); */
+
+	tl = tl_add_str(tl, T_helper, helper_name);
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	cn_reply->id.idx = CN_IDX_DRBD;
+	cn_reply->id.val = CN_VAL_DRBD;
+
+	cn_reply->seq = atomic_add_return(1, &drbd_nl_seq);
+	cn_reply->ack = 0; /* not used here. */
+	cn_reply->len = sizeof(struct drbd_nl_cfg_reply) +
+		(int)((char *)tl - (char *)reply->tag_list);
+	cn_reply->flags = 0;
+
+	reply->packet_type = P_call_helper;
+	reply->minor = mdev_to_minor(mdev);
+	reply->ret_code = NO_ERROR;
+
+	trace_drbd_netlink(cn_reply, 0);
+	cn_netlink_send(cn_reply, CN_IDX_DRBD, GFP_NOIO);
+}
+
+void drbd_bcast_ee(struct drbd_conf *mdev,
+		const char *reason, const int dgs,
+		const char* seen_hash, const char* calc_hash,
+		const struct drbd_epoch_entry* e)
+{
+	struct cn_msg *cn_reply;
+	struct drbd_nl_cfg_reply *reply;
+	struct bio_vec *bvec;
+	unsigned short *tl;
+	int i;
+
+	if (!e)
+		return;
+	if (!reason || !reason[0])
+		return;
+
+	/* apparently we have to memcpy twice, first to prepare the data for the
+	 * struct cn_msg, then within cn_netlink_send from the cn_msg to the
+	 * netlink skb. */
+	/* receiver thread context, which is not in the writeout path (of this node),
+	 * but may be in the writeout path of the _other_ node.
+	 * GFP_NOIO to avoid potential "distributed deadlock". */
+	cn_reply = kmalloc(
+		sizeof(struct cn_msg)+
+		sizeof(struct drbd_nl_cfg_reply)+
+		sizeof(struct dump_ee_tag_len_struct)+
+		sizeof(short int),
+		GFP_NOIO);
+
+	if (!cn_reply) {
+		dev_err(DEV, "could not kmalloc buffer for drbd_bcast_ee, sector %llu, size %u\n",
+				(unsigned long long)e->sector, e->size);
+		return;
+	}
+
+	reply = (struct drbd_nl_cfg_reply*)cn_reply->data;
+	tl = reply->tag_list;
+
+	tl = tl_add_str(tl, T_dump_ee_reason, reason);
+	tl = tl_add_blob(tl, T_seen_digest, seen_hash, dgs);
+	tl = tl_add_blob(tl, T_calc_digest, calc_hash, dgs);
+	tl = tl_add_int(tl, T_ee_sector, &e->sector);
+	tl = tl_add_int(tl, T_ee_block_id, &e->block_id);
+
+	put_unaligned(T_ee_data, tl++);
+	put_unaligned(e->size, tl++);
+
+	__bio_for_each_segment(bvec, e->private_bio, i, 0) {
+		void *d = kmap(bvec->bv_page);
+		memcpy(tl, d + bvec->bv_offset, bvec->bv_len);
+		kunmap(bvec->bv_page);
+		tl=(unsigned short*)((char*)tl + bvec->bv_len);
+	}
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	cn_reply->id.idx = CN_IDX_DRBD;
+	cn_reply->id.val = CN_VAL_DRBD;
+
+	cn_reply->seq = atomic_add_return(1,&drbd_nl_seq);
+	cn_reply->ack = 0; // not used here.
+	cn_reply->len = sizeof(struct drbd_nl_cfg_reply) +
+		(int)((char*)tl - (char*)reply->tag_list);
+	cn_reply->flags = 0;
+
+	reply->packet_type = P_dump_ee;
+	reply->minor = mdev_to_minor(mdev);
+	reply->ret_code = NO_ERROR;
+
+	trace_drbd_netlink(cn_reply, 0);
+	cn_netlink_send(cn_reply, CN_IDX_DRBD, GFP_NOIO);
+	kfree(cn_reply);
+}
+
+void drbd_bcast_sync_progress(struct drbd_conf *mdev)
+{
+	char buffer[sizeof(struct cn_msg)+
+		    sizeof(struct drbd_nl_cfg_reply)+
+		    sizeof(struct sync_progress_tag_len_struct)+
+		    sizeof(short int)];
+	struct cn_msg *cn_reply = (struct cn_msg *) buffer;
+	struct drbd_nl_cfg_reply *reply =
+		(struct drbd_nl_cfg_reply *)cn_reply->data;
+	unsigned short *tl = reply->tag_list;
+	unsigned long rs_left;
+	unsigned int res;
+
+	/* no local ref, no bitmap, no syncer progress, no broadcast. */
+	if (!get_ldev(mdev))
+		return;
+	drbd_get_syncer_progress(mdev, &rs_left, &res);
+	put_ldev(mdev);
+
+	tl = tl_add_int(tl, T_sync_progress, &res);
+	put_unaligned(TT_END, tl++); /* Close the tag list */
+
+	cn_reply->id.idx = CN_IDX_DRBD;
+	cn_reply->id.val = CN_VAL_DRBD;
+
+	cn_reply->seq = atomic_add_return(1, &drbd_nl_seq);
+	cn_reply->ack = 0; /* not used here. */
+	cn_reply->len = sizeof(struct drbd_nl_cfg_reply) +
+		(int)((char *)tl - (char *)reply->tag_list);
+	cn_reply->flags = 0;
+
+	reply->packet_type = P_sync_progress;
+	reply->minor = mdev_to_minor(mdev);
+	reply->ret_code = NO_ERROR;
+
+	trace_drbd_netlink(cn_reply, 0);
+	cn_netlink_send(cn_reply, CN_IDX_DRBD, GFP_NOIO);
+}
+
+int __init drbd_nl_init(void)
+{
+	static struct cb_id cn_id_drbd;
+	int err, try=10;
+
+	cn_id_drbd.val = CN_VAL_DRBD;
+	do {
+		cn_id_drbd.idx = cn_idx;
+		err = cn_add_callback(&cn_id_drbd, "cn_drbd", &drbd_connector_callback);
+		if (!err)
+			break;
+		cn_idx = (cn_idx + CN_IDX_STEP);
+	} while (try--);
+
+	if (err) {
+		printk(KERN_ERR "drbd: cn_drbd failed to register\n");
+		return err;
+	}
+
+	return 0;
+}
+
+void drbd_nl_cleanup(void)
+{
+	static struct cb_id cn_id_drbd;
+
+	cn_id_drbd.idx = cn_idx;
+	cn_id_drbd.val = CN_VAL_DRBD;
+
+	cn_del_callback(&cn_id_drbd);
+}
+
+void drbd_nl_send_reply(struct cn_msg *req, int ret_code)
+{
+	char buffer[sizeof(struct cn_msg)+sizeof(struct drbd_nl_cfg_reply)];
+	struct cn_msg *cn_reply = (struct cn_msg *) buffer;
+	struct drbd_nl_cfg_reply *reply =
+		(struct drbd_nl_cfg_reply *)cn_reply->data;
+	int rr;
+
+	cn_reply->id = req->id;
+
+	cn_reply->seq = req->seq;
+	cn_reply->ack = req->ack  + 1;
+	cn_reply->len = sizeof(struct drbd_nl_cfg_reply);
+	cn_reply->flags = 0;
+
+	reply->minor = ((struct drbd_nl_cfg_req *)req->data)->drbd_minor;
+	reply->ret_code = ret_code;
+
+	trace_drbd_netlink(cn_reply, 0);
+	rr = cn_netlink_send(cn_reply, CN_IDX_DRBD, GFP_NOIO);
+	if (rr && rr != -ESRCH)
+		printk(KERN_INFO "drbd: cn_netlink_send()=%d\n", rr);
+}
+