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    Subject[PATCH 08/16] DRBD: main
    Date
    The DRBD state engine, and lots of other stuff, that does not have its own
    source file.

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

    ---
    diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
    new file mode 100644
    index 0000000..ad29684
    --- /dev/null
    +++ b/drivers/block/drbd/drbd_main.c
    @@ -0,0 +1,3669 @@
    +/*
    + drbd.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/version.h>
    +
    +#include <asm/uaccess.h>
    +#include <asm/types.h>
    +#include <net/sock.h>
    +#include <linux/ctype.h>
    +#include <linux/smp_lock.h>
    +#include <linux/fs.h>
    +#include <linux/file.h>
    +#include <linux/proc_fs.h>
    +#include <linux/init.h>
    +#include <linux/mm.h>
    +#include <linux/drbd_config.h>
    +#include <linux/memcontrol.h>
    +#include <linux/mm_inline.h>
    +#include <linux/slab.h>
    +#include <linux/random.h>
    +#include <linux/reboot.h>
    +#include <linux/notifier.h>
    +#include <linux/kthread.h>
    +
    +#define __KERNEL_SYSCALLS__
    +#include <linux/unistd.h>
    +#include <linux/vmalloc.h>
    +
    +#include <linux/drbd.h>
    +#include <linux/drbd_limits.h>
    +#include "drbd_int.h"
    +#include "drbd_tracing.h"
    +#include "drbd_req.h" /* only for _req_mod in tl_release and tl_clear */
    +
    +#include "drbd_vli.h"
    +
    +struct after_state_chg_work {
    + struct drbd_work w;
    + union drbd_state os;
    + union drbd_state ns;
    + enum chg_state_flags flags;
    + struct completion *done;
    +};
    +
    +int drbdd_init(struct drbd_thread *);
    +int drbd_worker(struct drbd_thread *);
    +int drbd_asender(struct drbd_thread *);
    +
    +int drbd_init(void);
    +static int drbd_open(struct block_device *bdev, fmode_t mode);
    +static int drbd_release(struct gendisk *gd, fmode_t mode);
    +STATIC int w_after_state_ch(struct drbd_conf *mdev, struct drbd_work *w, int unused);
    +STATIC void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
    + union drbd_state ns, enum chg_state_flags flags);
    +STATIC int w_md_sync(struct drbd_conf *mdev, struct drbd_work *w, int unused);
    +STATIC void md_sync_timer_fn(unsigned long data);
    +STATIC int w_bitmap_io(struct drbd_conf *mdev, struct drbd_work *w, int unused);
    +
    +DEFINE_TRACE(drbd_unplug);
    +DEFINE_TRACE(drbd_uuid);
    +DEFINE_TRACE(drbd_ee);
    +DEFINE_TRACE(drbd_packet);
    +DEFINE_TRACE(drbd_md_io);
    +DEFINE_TRACE(drbd_epoch);
    +DEFINE_TRACE(drbd_netlink);
    +DEFINE_TRACE(drbd_actlog);
    +DEFINE_TRACE(drbd_bio);
    +DEFINE_TRACE(_drbd_resync);
    +DEFINE_TRACE(drbd_req);
    +
    +MODULE_AUTHOR("Philipp Reisner <phil@linbit.com>, "
    + "Lars Ellenberg <lars@linbit.com>");
    +MODULE_DESCRIPTION("drbd - Distributed Replicated Block Device v" REL_VERSION);
    +MODULE_LICENSE("GPL");
    +MODULE_PARM_DESC(minor_count, "Maximum number of drbd devices (1-255)");
    +MODULE_ALIAS_BLOCKDEV_MAJOR(DRBD_MAJOR);
    +
    +#include <linux/moduleparam.h>
    +/* allow_open_on_secondary */
    +MODULE_PARM_DESC(allow_oos, "DONT USE!");
    +/* thanks to these macros, if compiled into the kernel (not-module),
    + * this becomes the boot parameter drbd.minor_count */
    +module_param(minor_count, uint, 0444);
    +module_param(disable_sendpage, bool, 0644);
    +module_param(allow_oos, bool, 0);
    +module_param(cn_idx, uint, 0444);
    +module_param(proc_details, int, 0644);
    +
    +#ifdef DRBD_ENABLE_FAULTS
    +int enable_faults;
    +int fault_rate;
    +static int fault_count;
    +int fault_devs;
    +/* bitmap of enabled faults */
    +module_param(enable_faults, int, 0664);
    +/* fault rate % value - applies to all enabled faults */
    +module_param(fault_rate, int, 0664);
    +/* count of faults inserted */
    +module_param(fault_count, int, 0664);
    +/* bitmap of devices to insert faults on */
    +module_param(fault_devs, int, 0644);
    +#endif
    +
    +/* module parameter, defined */
    +unsigned int minor_count = 32;
    +int disable_sendpage;
    +int allow_oos;
    +unsigned int cn_idx = CN_IDX_DRBD;
    +int proc_details; /* Detail level in proc drbd*/
    +
    +/* Module parameter for setting the user mode helper program
    + * to run. Default is /sbin/drbdadm */
    +char usermode_helper[80] = "/sbin/drbdadm";
    +
    +module_param_string(usermode_helper, usermode_helper, sizeof(usermode_helper), 0644);
    +
    +/* in 2.6.x, our device mapping and config info contains our virtual gendisks
    + * as member "struct gendisk *vdisk;"
    + */
    +struct drbd_conf **minor_table;
    +
    +struct kmem_cache *drbd_request_cache;
    +struct kmem_cache *drbd_ee_cache;
    +mempool_t *drbd_request_mempool;
    +mempool_t *drbd_ee_mempool;
    +
    +/* I do not use a standard mempool, because:
    + 1) I want to hand out the preallocated objects first.
    + 2) I want to be able to interrupt sleeping allocation with a signal.
    + Note: This is a single linked list, the next pointer is the private
    + member of struct page.
    + */
    +struct page *drbd_pp_pool;
    +spinlock_t drbd_pp_lock;
    +int drbd_pp_vacant;
    +wait_queue_head_t drbd_pp_wait;
    +
    +DEFINE_RATELIMIT_STATE(drbd_ratelimit_state, 5 * HZ, 5);
    +
    +STATIC struct block_device_operations drbd_ops = {
    + .owner = THIS_MODULE,
    + .open = drbd_open,
    + .release = drbd_release,
    +};
    +
    +#define ARRY_SIZE(A) (sizeof(A)/sizeof(A[0]))
    +
    +#ifdef __CHECKER__
    +/* When checking with sparse, and this is an inline function, sparse will
    + give tons of false positives. When this is a real functions sparse works.
    + */
    +int _get_ldev_if_state(struct drbd_conf *mdev, enum drbd_disk_state mins)
    +{
    + int io_allowed;
    +
    + atomic_inc(&mdev->local_cnt);
    + io_allowed = (mdev->state.disk >= mins);
    + if (!io_allowed) {
    + if (atomic_dec_and_test(&mdev->local_cnt))
    + wake_up(&mdev->misc_wait);
    + }
    + return io_allowed;
    +}
    +
    +#endif
    +
    +/**
    + * DOC: The transfer log
    + *
    + * The transfer log is a single linked list of &struct drbd_tl_epoch objects.
    + * mdev->newest_tle points to the head, mdev->oldest_tle points to the tail
    + * of the list. There is always at least one &struct drbd_tl_epoch object.
    + *
    + * Each &struct drbd_tl_epoch has a circular double linked list of requests
    + * attached.
    + */
    +STATIC int tl_init(struct drbd_conf *mdev)
    +{
    + struct drbd_tl_epoch *b;
    +
    + b = kmalloc(sizeof(struct drbd_tl_epoch), GFP_KERNEL);
    + if (!b)
    + return 0;
    + INIT_LIST_HEAD(&b->requests);
    + INIT_LIST_HEAD(&b->w.list);
    + b->next = NULL;
    + b->br_number = 4711;
    + b->n_req = 0;
    + b->w.cb = NULL; /* if this is != NULL, we need to dec_ap_pending in tl_clear */
    +
    + mdev->oldest_tle = b;
    + mdev->newest_tle = b;
    + INIT_LIST_HEAD(&mdev->out_of_sequence_requests);
    +
    + mdev->tl_hash = NULL;
    + mdev->tl_hash_s = 0;
    +
    + return 1;
    +}
    +
    +STATIC void tl_cleanup(struct drbd_conf *mdev)
    +{
    + D_ASSERT(mdev->oldest_tle == mdev->newest_tle);
    + D_ASSERT(list_empty(&mdev->out_of_sequence_requests));
    + kfree(mdev->oldest_tle);
    + mdev->oldest_tle = NULL;
    + kfree(mdev->unused_spare_tle);
    + mdev->unused_spare_tle = NULL;
    + kfree(mdev->tl_hash);
    + mdev->tl_hash = NULL;
    + mdev->tl_hash_s = 0;
    +}
    +
    +/**
    + * _tl_add_barrier() - Adds a barrier to the transfer log
    + * @mdev: DRBD device.
    + * @new: Barrier to be added before the current head of the TL.
    + *
    + * The caller must hold the req_lock.
    + */
    +void _tl_add_barrier(struct drbd_conf *mdev, struct drbd_tl_epoch *new)
    +{
    + struct drbd_tl_epoch *newest_before;
    +
    + INIT_LIST_HEAD(&new->requests);
    + INIT_LIST_HEAD(&new->w.list);
    + new->w.cb = NULL; /* if this is != NULL, we need to dec_ap_pending in tl_clear */
    + new->next = NULL;
    + new->n_req = 0;
    +
    + newest_before = mdev->newest_tle;
    + /* never send a barrier number == 0, because that is special-cased
    + * when using TCQ for our write ordering code */
    + new->br_number = (newest_before->br_number+1) ?: 1;
    + if (mdev->newest_tle != new) {
    + mdev->newest_tle->next = new;
    + mdev->newest_tle = new;
    + }
    +}
    +
    +/**
    + * tl_release() - Free or recycle the oldest &struct drbd_tl_epoch object of the TL
    + * @mdev: DRBD device.
    + * @barrier_nr: Expected identifier of the DRBD write barrier packet.
    + * @set_size: Expected number of requests before that barrier.
    + *
    + * In case the passed barrier_nr or set_size does not match the oldest
    + * &struct drbd_tl_epoch objects this function will cause a termination
    + * of the connection.
    + */
    +void tl_release(struct drbd_conf *mdev, unsigned int barrier_nr,
    + unsigned int set_size)
    +{
    + struct drbd_tl_epoch *b, *nob; /* next old barrier */
    + struct list_head *le, *tle;
    + struct drbd_request *r;
    +
    + spin_lock_irq(&mdev->req_lock);
    +
    + b = mdev->oldest_tle;
    +
    + /* first some paranoia code */
    + if (b == NULL) {
    + dev_err(DEV, "BAD! BarrierAck #%u received, but no epoch in tl!?\n",
    + barrier_nr);
    + goto bail;
    + }
    + if (b->br_number != barrier_nr) {
    + dev_err(DEV, "BAD! BarrierAck #%u received, expected #%u!\n",
    + barrier_nr, b->br_number);
    + goto bail;
    + }
    + if (b->n_req != set_size) {
    + dev_err(DEV, "BAD! BarrierAck #%u received with n_req=%u, expected n_req=%u!\n",
    + barrier_nr, set_size, b->n_req);
    + goto bail;
    + }
    +
    + /* Clean up list of requests processed during current epoch */
    + list_for_each_safe(le, tle, &b->requests) {
    + r = list_entry(le, struct drbd_request, tl_requests);
    + _req_mod(r, barrier_acked, 0);
    + }
    + /* There could be requests on the list waiting for completion
    + of the write to the local disk. To avoid corruptions of
    + slab's data structures we have to remove the lists head.
    +
    + Also there could have been a barrier ack out of sequence, overtaking
    + the write acks - which would be a but and violating write ordering.
    + To not deadlock in case we lose connection while such requests are
    + still pending, we need some way to find them for the
    + _req_mode(connection_lost_while_pending).
    +
    + These have been list_move'd to the out_of_sequence_requests list in
    + _req_mod(, barrier_acked,) above.
    + */
    + list_del_init(&b->requests);
    +
    + nob = b->next;
    + if (test_and_clear_bit(CREATE_BARRIER, &mdev->flags)) {
    + _tl_add_barrier(mdev, b);
    + if (nob)
    + mdev->oldest_tle = nob;
    + /* if nob == NULL b was the only barrier, and becomes the new
    + barrer. Threfore mdev->oldest_tle points already to b */
    + } else {
    + D_ASSERT(nob != NULL);
    + mdev->oldest_tle = nob;
    + kfree(b);
    + }
    +
    + spin_unlock_irq(&mdev->req_lock);
    + dec_ap_pending(mdev);
    +
    + return;
    +
    +bail:
    + spin_unlock_irq(&mdev->req_lock);
    + drbd_force_state(mdev, NS(conn, C_PROTOCOL_ERROR));
    +}
    +
    +
    +/**
    + * tl_clear() - Clears all requests and &struct drbd_tl_epoch objects out of the TL
    + * @mdev: DRBD device.
    + *
    + * This is called after the connection to the peer was lost. The storage covered
    + * by the requests on the transfer gets marked as our of sync. Called from the
    + * receiver thread and the worker thread.
    + */
    +void tl_clear(struct drbd_conf *mdev)
    +{
    + struct drbd_tl_epoch *b, *tmp;
    + struct list_head *le, *tle;
    + struct drbd_request *r;
    + int new_initial_bnr = net_random();
    +
    + spin_lock_irq(&mdev->req_lock);
    +
    + b = mdev->oldest_tle;
    + while (b) {
    + list_for_each_safe(le, tle, &b->requests) {
    + r = list_entry(le, struct drbd_request, tl_requests);
    + _req_mod(r, connection_lost_while_pending, 0);
    + }
    + tmp = b->next;
    +
    + /* there could still be requests on that ring list,
    + * in case local io is still pending */
    + list_del(&b->requests);
    +
    + /* dec_ap_pending corresponding to queue_barrier.
    + * the newest barrier may not have been queued yet,
    + * in which case w.cb is still NULL. */
    + if (b->w.cb != NULL)
    + dec_ap_pending(mdev);
    +
    + if (b == mdev->newest_tle) {
    + /* recycle, but reinit! */
    + D_ASSERT(tmp == NULL);
    + INIT_LIST_HEAD(&b->requests);
    + INIT_LIST_HEAD(&b->w.list);
    + b->w.cb = NULL;
    + b->br_number = new_initial_bnr;
    + b->n_req = 0;
    +
    + mdev->oldest_tle = b;
    + break;
    + }
    + kfree(b);
    + b = tmp;
    + }
    +
    + /* we expect this list to be empty. */
    + D_ASSERT(list_empty(&mdev->out_of_sequence_requests));
    +
    + /* but just in case, clean it up anyways! */
    + list_for_each_safe(le, tle, &mdev->out_of_sequence_requests) {
    + r = list_entry(le, struct drbd_request, tl_requests);
    + _req_mod(r, connection_lost_while_pending, 0);
    + }
    +
    + /* ensure bit indicating barrier is required is clear */
    + clear_bit(CREATE_BARRIER, &mdev->flags);
    +
    + spin_unlock_irq(&mdev->req_lock);
    +}
    +
    +/**
    + * drbd_io_error() - Detach from the local disk of so configured with the on_io_error setting
    + * @mdev: DRBD device.
    + * @force_detach: Detach no matter how on_io_error is set (meta data IO error)
    + *
    + * Should be called in the unlikely(!drbd_bio_uptodate(e->bio)) case from
    + * kernel thread context. See also drbd_chk_io_error().
    + */
    +int drbd_io_error(struct drbd_conf *mdev, int force_detach)
    +{
    + enum drbd_io_error_p eh;
    + unsigned long flags;
    + int send;
    + int ok = 1;
    +
    + eh = EP_PASS_ON;
    + if (get_ldev_if_state(mdev, D_FAILED)) {
    + eh = mdev->ldev->dc.on_io_error;
    + put_ldev(mdev);
    + }
    +
    + if (!force_detach && eh == EP_PASS_ON)
    + return 1;
    +
    + spin_lock_irqsave(&mdev->req_lock, flags);
    + send = (mdev->state.disk == D_FAILED);
    + if (send)
    + _drbd_set_state(_NS(mdev, disk, D_DISKLESS), CS_HARD, NULL);
    + spin_unlock_irqrestore(&mdev->req_lock, flags);
    +
    + if (!send)
    + return ok;
    +
    + if (mdev->state.conn >= C_CONNECTED) {
    + ok = drbd_send_state(mdev);
    + if (ok)
    + dev_warn(DEV, "Notified peer that my disk is broken.\n");
    + else
    + dev_err(DEV, "Sending state in drbd_io_error() failed\n");
    + }
    +
    + /* Make sure we try to flush meta-data to disk - we come
    + * in here because of a local disk error so it might fail
    + * but we still need to try -- both because the error might
    + * be in the data portion of the disk and because we need
    + * to ensure the md-sync-timer is stopped if running. */
    + drbd_md_sync(mdev);
    +
    + /* Releasing the backing device is done in after_state_ch() */
    +
    + if (eh == EP_CALL_HELPER)
    + drbd_khelper(mdev, "local-io-error");
    +
    + return ok;
    +}
    +
    +/**
    + * cl_wide_st_chg() - TRUE if the state change is a cluster wide one
    + * @mdev: DRBD device.
    + * @os: old (current) state.
    + * @ns: new (wanted) state.
    + */
    +STATIC int cl_wide_st_chg(struct drbd_conf *mdev,
    + union drbd_state os, union drbd_state ns)
    +{
    + return (os.conn >= C_CONNECTED && ns.conn >= C_CONNECTED &&
    + ((os.role != R_PRIMARY && ns.role == R_PRIMARY) ||
    + (os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
    + (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S) ||
    + (os.disk != D_DISKLESS && ns.disk == D_DISKLESS))) ||
    + (os.conn >= C_CONNECTED && ns.conn == C_DISCONNECTING) ||
    + (os.conn == C_CONNECTED && ns.conn == C_VERIFY_S);
    +}
    +
    +int drbd_change_state(struct drbd_conf *mdev, enum chg_state_flags f,
    + union drbd_state mask, union drbd_state val)
    +{
    + unsigned long flags;
    + union drbd_state os, ns;
    + int rv;
    +
    + spin_lock_irqsave(&mdev->req_lock, flags);
    + os = mdev->state;
    + ns.i = (os.i & ~mask.i) | val.i;
    + rv = _drbd_set_state(mdev, ns, f, NULL);
    + ns = mdev->state;
    + spin_unlock_irqrestore(&mdev->req_lock, flags);
    +
    + return rv;
    +}
    +
    +/**
    + * drbd_force_state() - Impose a change which happens outside our control on our state
    + * @mdev: DRBD device.
    + * @mask: mask of state bits to change.
    + * @val: value of new state bits.
    + */
    +void drbd_force_state(struct drbd_conf *mdev,
    + union drbd_state mask, union drbd_state val)
    +{
    + drbd_change_state(mdev, CS_HARD, mask, val);
    +}
    +
    +STATIC int is_valid_state(struct drbd_conf *mdev, union drbd_state ns);
    +STATIC int is_valid_state_transition(struct drbd_conf *,
    + union drbd_state, union drbd_state);
    +STATIC union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state os,
    + union drbd_state ns, int *warn_sync_abort);
    +int drbd_send_state_req(struct drbd_conf *,
    + union drbd_state, union drbd_state);
    +
    +STATIC enum drbd_state_ret_codes _req_st_cond(struct drbd_conf *mdev,
    + union drbd_state mask, union drbd_state val)
    +{
    + union drbd_state os, ns;
    + unsigned long flags;
    + int rv;
    +
    + if (test_and_clear_bit(CL_ST_CHG_SUCCESS, &mdev->flags))
    + return SS_CW_SUCCESS;
    +
    + if (test_and_clear_bit(CL_ST_CHG_FAIL, &mdev->flags))
    + return SS_CW_FAILED_BY_PEER;
    +
    + rv = 0;
    + spin_lock_irqsave(&mdev->req_lock, flags);
    + os = mdev->state;
    + ns.i = (os.i & ~mask.i) | val.i;
    + ns = sanitize_state(mdev, os, ns, NULL);
    +
    + if (!cl_wide_st_chg(mdev, os, ns))
    + rv = SS_CW_NO_NEED;
    + if (!rv) {
    + rv = is_valid_state(mdev, ns);
    + if (rv == SS_SUCCESS) {
    + rv = is_valid_state_transition(mdev, ns, os);
    + if (rv == SS_SUCCESS)
    + rv = 0; /* cont waiting, otherwise fail. */
    + }
    + }
    + spin_unlock_irqrestore(&mdev->req_lock, flags);
    +
    + return rv;
    +}
    +
    +/**
    + * drbd_req_state() - Perform an eventually cluster wide state change
    + * @mdev: DRBD device.
    + * @mask: mask of state bits to change.
    + * @val: value of new state bits.
    + * @f: flags
    + *
    + * Should not be called directly, use drbd_request_state() or
    + * _drbd_request_state().
    + */
    +STATIC int drbd_req_state(struct drbd_conf *mdev,
    + union drbd_state mask, union drbd_state val,
    + enum chg_state_flags f)
    +{
    + struct completion done;
    + unsigned long flags;
    + union drbd_state os, ns;
    + int rv;
    +
    + init_completion(&done);
    +
    + if (f & CS_SERIALIZE)
    + mutex_lock(&mdev->state_mutex);
    +
    + spin_lock_irqsave(&mdev->req_lock, flags);
    + os = mdev->state;
    + ns.i = (os.i & ~mask.i) | val.i;
    + ns = sanitize_state(mdev, os, ns, NULL);
    +
    + if (cl_wide_st_chg(mdev, os, ns)) {
    + rv = is_valid_state(mdev, ns);
    + if (rv == SS_SUCCESS)
    + rv = is_valid_state_transition(mdev, ns, os);
    + spin_unlock_irqrestore(&mdev->req_lock, flags);
    +
    + if (rv < SS_SUCCESS) {
    + if (f & CS_VERBOSE)
    + print_st_err(mdev, os, ns, rv);
    + goto abort;
    + }
    +
    + drbd_state_lock(mdev);
    + if (!drbd_send_state_req(mdev, mask, val)) {
    + drbd_state_unlock(mdev);
    + rv = SS_CW_FAILED_BY_PEER;
    + if (f & CS_VERBOSE)
    + print_st_err(mdev, os, ns, rv);
    + goto abort;
    + }
    +
    + wait_event(mdev->state_wait,
    + (rv = _req_st_cond(mdev, mask, val)));
    +
    + if (rv < SS_SUCCESS) {
    + drbd_state_unlock(mdev);
    + if (f & CS_VERBOSE)
    + print_st_err(mdev, os, ns, rv);
    + goto abort;
    + }
    + spin_lock_irqsave(&mdev->req_lock, flags);
    + os = mdev->state;
    + ns.i = (os.i & ~mask.i) | val.i;
    + rv = _drbd_set_state(mdev, ns, f, &done);
    + drbd_state_unlock(mdev);
    + } else {
    + rv = _drbd_set_state(mdev, ns, f, &done);
    + }
    +
    + spin_unlock_irqrestore(&mdev->req_lock, flags);
    +
    + if (f & CS_WAIT_COMPLETE && rv == SS_SUCCESS) {
    + D_ASSERT(current != mdev->worker.task);
    + wait_for_completion(&done);
    + }
    +
    +abort:
    + if (f & CS_SERIALIZE)
    + mutex_unlock(&mdev->state_mutex);
    +
    + return rv;
    +}
    +
    +/**
    + * _drbd_request_state() - Reqest a state change (with flags)
    + * @mdev: DRBD device.
    + * @mask: mask of state bits to change.
    + * @val: value of new state bits.
    + * @f: flags
    + *
    + * Cousin of drbd_request_state(), use full with the CS_WAIT_COMPLETE
    + * flag, or when logging of failed state change requests is not desired.
    + */
    +int _drbd_request_state(struct drbd_conf *mdev, union drbd_state mask,
    + union drbd_state val, enum chg_state_flags f)
    +{
    + int rv;
    +
    + wait_event(mdev->state_wait,
    + (rv = drbd_req_state(mdev, mask, val, f)) != SS_IN_TRANSIENT_STATE);
    +
    + return rv;
    +}
    +
    +STATIC void print_st(struct drbd_conf *mdev, char *name, union drbd_state ns)
    +{
    + dev_err(DEV, " %s = { cs:%s ro:%s/%s ds:%s/%s %c%c%c%c }\n",
    + name,
    + conns_to_name(ns.conn),
    + roles_to_name(ns.role),
    + roles_to_name(ns.peer),
    + disks_to_name(ns.disk),
    + disks_to_name(ns.pdsk),
    + ns.susp ? 's' : 'r',
    + ns.aftr_isp ? 'a' : '-',
    + ns.peer_isp ? 'p' : '-',
    + ns.user_isp ? 'u' : '-'
    + );
    +}
    +
    +void print_st_err(struct drbd_conf *mdev,
    + union drbd_state os, union drbd_state ns, int err)
    +{
    + if (err == SS_IN_TRANSIENT_STATE)
    + return;
    + dev_err(DEV, "State change failed: %s\n", set_st_err_name(err));
    + print_st(mdev, " state", os);
    + print_st(mdev, "wanted", ns);
    +}
    +
    +
    +#define peers_to_name roles_to_name
    +#define pdsks_to_name disks_to_name
    +
    +#define susps_to_name(A) ((A) ? "1" : "0")
    +#define aftr_isps_to_name(A) ((A) ? "1" : "0")
    +#define peer_isps_to_name(A) ((A) ? "1" : "0")
    +#define user_isps_to_name(A) ((A) ? "1" : "0")
    +
    +#define PSC(A) \
    + ({ if (ns.A != os.A) { \
    + pbp += sprintf(pbp, #A "( %s -> %s ) ", \
    + A##s_to_name(os.A), \
    + A##s_to_name(ns.A)); \
    + } })
    +
    +/**
    + * is_valid_state() - Returns an SS_ error code if ns is not valid
    + * @mdev: DRBD device.
    + * @ns: State to consider.
    + */
    +STATIC int is_valid_state(struct drbd_conf *mdev, union drbd_state ns)
    +{
    + /* See drbd_state_sw_errors in drbd_strings.c */
    +
    + enum drbd_fencing_p fp;
    + int rv = SS_SUCCESS;
    +
    + fp = FP_DONT_CARE;
    + if (get_ldev(mdev)) {
    + fp = mdev->ldev->dc.fencing;
    + put_ldev(mdev);
    + }
    +
    + if (get_net_conf(mdev)) {
    + if (!mdev->net_conf->two_primaries &&
    + ns.role == R_PRIMARY && ns.peer == R_PRIMARY)
    + rv = SS_TWO_PRIMARIES;
    + put_net_conf(mdev);
    + }
    +
    + if (rv <= 0)
    + /* already found a reason to abort */;
    + else if (ns.role == R_SECONDARY && mdev->open_cnt)
    + rv = SS_DEVICE_IN_USE;
    +
    + else if (ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.disk < D_UP_TO_DATE)
    + rv = SS_NO_UP_TO_DATE_DISK;
    +
    + else if (fp >= FP_RESOURCE &&
    + ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.pdsk >= D_UNKNOWN)
    + rv = SS_PRIMARY_NOP;
    +
    + else if (ns.role == R_PRIMARY && ns.disk <= D_INCONSISTENT && ns.pdsk <= D_INCONSISTENT)
    + rv = SS_NO_UP_TO_DATE_DISK;
    +
    + else if (ns.conn > C_CONNECTED && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE)
    + rv = SS_BOTH_INCONSISTENT;
    +
    + else if (ns.conn > C_CONNECTED && (ns.disk == D_DISKLESS || ns.pdsk == D_DISKLESS))
    + rv = SS_SYNCING_DISKLESS;
    +
    + else if ((ns.conn == C_CONNECTED ||
    + ns.conn == C_WF_BITMAP_S ||
    + ns.conn == C_SYNC_SOURCE ||
    + ns.conn == C_PAUSED_SYNC_S) &&
    + ns.disk == D_OUTDATED)
    + rv = SS_CONNECTED_OUTDATES;
    +
    + else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
    + (mdev->sync_conf.verify_alg[0] == 0))
    + rv = SS_NO_VERIFY_ALG;
    +
    + else if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
    + mdev->agreed_pro_version < 88)
    + rv = SS_NOT_SUPPORTED;
    +
    + return rv;
    +}
    +
    +/**
    + * is_valid_state_transition() - Returns an SS_ error code if the state transition is not possible
    + * @mdev: DRBD device.
    + * @ns: new state.
    + * @os: old state.
    + */
    +STATIC int is_valid_state_transition(struct drbd_conf *mdev,
    + union drbd_state ns, union drbd_state os)
    +{
    + int rv = SS_SUCCESS;
    +
    + if ((ns.conn == C_STARTING_SYNC_T || ns.conn == C_STARTING_SYNC_S) &&
    + os.conn > C_CONNECTED)
    + rv = SS_RESYNC_RUNNING;
    +
    + if (ns.conn == C_DISCONNECTING && os.conn == C_STANDALONE)
    + rv = SS_ALREADY_STANDALONE;
    +
    + if (ns.disk > D_ATTACHING && os.disk == D_DISKLESS)
    + rv = SS_IS_DISKLESS;
    +
    + if (ns.conn == C_WF_CONNECTION && os.conn < C_UNCONNECTED)
    + rv = SS_NO_NET_CONFIG;
    +
    + if (ns.disk == D_OUTDATED && os.disk < D_OUTDATED && os.disk != D_ATTACHING)
    + rv = SS_LOWER_THAN_OUTDATED;
    +
    + if (ns.conn == C_DISCONNECTING && os.conn == C_UNCONNECTED)
    + rv = SS_IN_TRANSIENT_STATE;
    +
    + if (ns.conn == os.conn && ns.conn == C_WF_REPORT_PARAMS)
    + rv = SS_IN_TRANSIENT_STATE;
    +
    + if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) && os.conn < C_CONNECTED)
    + rv = SS_NEED_CONNECTION;
    +
    + if ((ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T) &&
    + ns.conn != os.conn && os.conn > C_CONNECTED)
    + rv = SS_RESYNC_RUNNING;
    +
    + if ((ns.conn == C_STARTING_SYNC_S || ns.conn == C_STARTING_SYNC_T) &&
    + os.conn < C_CONNECTED)
    + rv = SS_NEED_CONNECTION;
    +
    + return rv;
    +}
    +
    +/**
    + * sanitize_state() - Resolves implicitly necessary additional changes to a state transition
    + * @mdev: DRBD device.
    + * @os: old state.
    + * @ns: new state.
    + * @warn_sync_abort:
    + *
    + * When we loose connection, we have to set the state of the peers disk (pdsk)
    + * to D_UNKNOWN. This rule and many more along those lines are in this function.
    + */
    +STATIC union drbd_state sanitize_state(struct drbd_conf *mdev, union drbd_state os,
    + union drbd_state ns, int *warn_sync_abort)
    +{
    + enum drbd_fencing_p fp;
    +
    + fp = FP_DONT_CARE;
    + if (get_ldev(mdev)) {
    + fp = mdev->ldev->dc.fencing;
    + put_ldev(mdev);
    + }
    +
    + /* Dissalow Network errors to configure a device's network part */
    + if ((ns.conn >= C_TIMEOUT && ns.conn <= C_TEAR_DOWN) &&
    + os.conn <= C_DISCONNECTING)
    + ns.conn = os.conn;
    +
    + /* After a network error (+C_TEAR_DOWN) only C_UNCONNECTED or C_DISCONNECTING can follow */
    + if (os.conn >= C_TIMEOUT && os.conn <= C_TEAR_DOWN &&
    + ns.conn != C_UNCONNECTED && ns.conn != C_DISCONNECTING)
    + ns.conn = os.conn;
    +
    + /* After C_DISCONNECTING only C_STANDALONE may follow */
    + if (os.conn == C_DISCONNECTING && ns.conn != C_STANDALONE)
    + ns.conn = os.conn;
    +
    + if (ns.conn < C_CONNECTED) {
    + ns.peer_isp = 0;
    + ns.peer = R_UNKNOWN;
    + if (ns.pdsk > D_UNKNOWN || ns.pdsk < D_INCONSISTENT)
    + ns.pdsk = D_UNKNOWN;
    + }
    +
    + /* Clear the aftr_isp when becoming unconfigured */
    + if (ns.conn == C_STANDALONE && ns.disk == D_DISKLESS && ns.role == R_SECONDARY)
    + ns.aftr_isp = 0;
    +
    + if (ns.conn <= C_DISCONNECTING && ns.disk == D_DISKLESS)
    + ns.pdsk = D_UNKNOWN;
    +
    + /* Abort resync if a disk fails/detaches */
    + if (os.conn > C_CONNECTED && ns.conn > C_CONNECTED &&
    + (ns.disk <= D_FAILED || ns.pdsk <= D_FAILED)) {
    + if (warn_sync_abort)
    + *warn_sync_abort = 1;
    + ns.conn = C_CONNECTED;
    + }
    +
    + if (ns.conn >= C_CONNECTED &&
    + ((ns.disk == D_CONSISTENT || ns.disk == D_OUTDATED) ||
    + (ns.disk == D_NEGOTIATING && ns.conn == C_WF_BITMAP_T))) {
    + switch (ns.conn) {
    + case C_WF_BITMAP_T:
    + case C_PAUSED_SYNC_T:
    + ns.disk = D_OUTDATED;
    + break;
    + case C_CONNECTED:
    + case C_WF_BITMAP_S:
    + case C_SYNC_SOURCE:
    + case C_PAUSED_SYNC_S:
    + ns.disk = D_UP_TO_DATE;
    + break;
    + case C_SYNC_TARGET:
    + ns.disk = D_INCONSISTENT;
    + dev_warn(DEV, "Implicitly set disk state Inconsistent!\n");
    + break;
    + }
    + if (os.disk == D_OUTDATED && ns.disk == D_UP_TO_DATE)
    + dev_warn(DEV, "Implicitly set disk from Outdated to UpToDate\n");
    + }
    +
    + if (ns.conn >= C_CONNECTED &&
    + (ns.pdsk == D_CONSISTENT || ns.pdsk == D_OUTDATED)) {
    + switch (ns.conn) {
    + case C_CONNECTED:
    + case C_WF_BITMAP_T:
    + case C_PAUSED_SYNC_T:
    + case C_SYNC_TARGET:
    + ns.pdsk = D_UP_TO_DATE;
    + break;
    + case C_WF_BITMAP_S:
    + case C_PAUSED_SYNC_S:
    + ns.pdsk = D_OUTDATED;
    + break;
    + case C_SYNC_SOURCE:
    + ns.pdsk = D_INCONSISTENT;
    + dev_warn(DEV, "Implicitly set pdsk Inconsistent!\n");
    + break;
    + }
    + if (os.pdsk == D_OUTDATED && ns.pdsk == D_UP_TO_DATE)
    + dev_warn(DEV, "Implicitly set pdsk from Outdated to UpToDate\n");
    + }
    +
    + /* Connection breaks down before we finished "Negotiating" */
    + if (ns.conn < C_CONNECTED && ns.disk == D_NEGOTIATING &&
    + get_ldev_if_state(mdev, D_NEGOTIATING)) {
    + if (mdev->ed_uuid == mdev->ldev->md.uuid[UI_CURRENT]) {
    + ns.disk = mdev->new_state_tmp.disk;
    + ns.pdsk = mdev->new_state_tmp.pdsk;
    + } else {
    + dev_alert(DEV, "Connection lost while negotiating, no data!\n");
    + ns.disk = D_DISKLESS;
    + ns.pdsk = D_UNKNOWN;
    + }
    + put_ldev(mdev);
    + }
    +
    + if (fp == FP_STONITH &&
    + (ns.role == R_PRIMARY &&
    + ns.conn < C_CONNECTED &&
    + ns.pdsk > D_OUTDATED))
    + ns.susp = 1;
    +
    + if (ns.aftr_isp || ns.peer_isp || ns.user_isp) {
    + if (ns.conn == C_SYNC_SOURCE)
    + ns.conn = C_PAUSED_SYNC_S;
    + if (ns.conn == C_SYNC_TARGET)
    + ns.conn = C_PAUSED_SYNC_T;
    + } else {
    + if (ns.conn == C_PAUSED_SYNC_S)
    + ns.conn = C_SYNC_SOURCE;
    + if (ns.conn == C_PAUSED_SYNC_T)
    + ns.conn = C_SYNC_TARGET;
    + }
    +
    + return ns;
    +}
    +
    +/**
    + * __drbd_set_state() - Set a new DRBD state
    + * @mdev: DRBD device.
    + * @ns: new state.
    + * @flags: Flags
    + * @done: Optional completion, that will get completed after the after_state_ch() finished
    + *
    + * Caller needs to hold req_lock, and global_state_lock. Do not call directly.
    + */
    +int __drbd_set_state(struct drbd_conf *mdev,
    + union drbd_state ns, enum chg_state_flags flags,
    + struct completion *done)
    +{
    + union drbd_state os;
    + int rv = SS_SUCCESS;
    + int warn_sync_abort = 0;
    + struct after_state_chg_work *ascw;
    +
    + os = mdev->state;
    +
    + ns = sanitize_state(mdev, os, ns, &warn_sync_abort);
    +
    + if (ns.i == os.i)
    + return SS_NOTHING_TO_DO;
    +
    + if (!(flags & CS_HARD)) {
    + /* pre-state-change checks ; only look at ns */
    + /* See drbd_state_sw_errors in drbd_strings.c */
    +
    + rv = is_valid_state(mdev, ns);
    + if (rv < SS_SUCCESS) {
    + /* If the old state was illegal as well, then let
    + this happen...*/
    +
    + if (is_valid_state(mdev, os) == rv) {
    + dev_err(DEV, "Considering state change from bad state. "
    + "Error would be: '%s'\n",
    + set_st_err_name(rv));
    + print_st(mdev, "old", os);
    + print_st(mdev, "new", ns);
    + rv = is_valid_state_transition(mdev, ns, os);
    + }
    + } else
    + rv = is_valid_state_transition(mdev, ns, os);
    + }
    +
    + if (rv < SS_SUCCESS) {
    + if (flags & CS_VERBOSE)
    + print_st_err(mdev, os, ns, rv);
    + return rv;
    + }
    +
    + if (warn_sync_abort)
    + dev_warn(DEV, "Resync aborted.\n");
    +
    + {
    + char *pbp, pb[300];
    + pbp = pb;
    + *pbp = 0;
    + PSC(role);
    + PSC(peer);
    + PSC(conn);
    + PSC(disk);
    + PSC(pdsk);
    + PSC(susp);
    + PSC(aftr_isp);
    + PSC(peer_isp);
    + PSC(user_isp);
    + dev_info(DEV, "%s\n", pb);
    + }
    +
    + /* solve the race between becoming unconfigured,
    + * worker doing the cleanup, and
    + * admin reconfiguring us:
    + * on (re)configure, first set CONFIG_PENDING,
    + * then wait for a potentially exiting worker,
    + * start the worker, and schedule one no_op.
    + * then proceed with configuration.
    + */
    + if (ns.disk == D_DISKLESS &&
    + ns.conn == C_STANDALONE &&
    + ns.role == R_SECONDARY &&
    + !test_and_set_bit(CONFIG_PENDING, &mdev->flags))
    + set_bit(DEVICE_DYING, &mdev->flags);
    +
    + mdev->state.i = ns.i;
    + wake_up(&mdev->misc_wait);
    + wake_up(&mdev->state_wait);
    +
    + /* post-state-change actions */
    + if (os.conn >= C_SYNC_SOURCE && ns.conn <= C_CONNECTED) {
    + set_bit(STOP_SYNC_TIMER, &mdev->flags);
    + mod_timer(&mdev->resync_timer, jiffies);
    + }
    +
    + if ((os.conn == C_PAUSED_SYNC_T || os.conn == C_PAUSED_SYNC_S) &&
    + (ns.conn == C_SYNC_TARGET || ns.conn == C_SYNC_SOURCE)) {
    + dev_info(DEV, "Syncer continues.\n");
    + mdev->rs_paused += (long)jiffies-(long)mdev->rs_mark_time;
    + if (ns.conn == C_SYNC_TARGET) {
    + if (!test_and_clear_bit(STOP_SYNC_TIMER, &mdev->flags))
    + mod_timer(&mdev->resync_timer, jiffies);
    + /* This if (!test_bit) is only needed for the case
    + that a device that has ceased to used its timer,
    + i.e. it is already in drbd_resync_finished() gets
    + paused and resumed. */
    + }
    + }
    +
    + if ((os.conn == C_SYNC_TARGET || os.conn == C_SYNC_SOURCE) &&
    + (ns.conn == C_PAUSED_SYNC_T || ns.conn == C_PAUSED_SYNC_S)) {
    + dev_info(DEV, "Resync suspended\n");
    + mdev->rs_mark_time = jiffies;
    + if (ns.conn == C_PAUSED_SYNC_T)
    + set_bit(STOP_SYNC_TIMER, &mdev->flags);
    + }
    +
    + if (os.conn == C_CONNECTED &&
    + (ns.conn == C_VERIFY_S || ns.conn == C_VERIFY_T)) {
    + mdev->ov_position = 0;
    + mdev->ov_left =
    + mdev->rs_total =
    + mdev->rs_mark_left = drbd_bm_bits(mdev);
    + mdev->rs_start =
    + mdev->rs_mark_time = jiffies;
    + mdev->ov_last_oos_size = 0;
    + mdev->ov_last_oos_start = 0;
    +
    + if (ns.conn == C_VERIFY_S)
    + mod_timer(&mdev->resync_timer, jiffies);
    + }
    +
    + if (get_ldev(mdev)) {
    + u32 mdf = mdev->ldev->md.flags & ~(MDF_CONSISTENT|MDF_PRIMARY_IND|
    + MDF_CONNECTED_IND|MDF_WAS_UP_TO_DATE|
    + MDF_PEER_OUT_DATED|MDF_CRASHED_PRIMARY);
    +
    + if (test_bit(CRASHED_PRIMARY, &mdev->flags))
    + mdf |= MDF_CRASHED_PRIMARY;
    + if (mdev->state.role == R_PRIMARY ||
    + (mdev->state.pdsk < D_INCONSISTENT && mdev->state.peer == R_PRIMARY))
    + mdf |= MDF_PRIMARY_IND;
    + if (mdev->state.conn > C_WF_REPORT_PARAMS)
    + mdf |= MDF_CONNECTED_IND;
    + if (mdev->state.disk > D_INCONSISTENT)
    + mdf |= MDF_CONSISTENT;
    + if (mdev->state.disk > D_OUTDATED)
    + mdf |= MDF_WAS_UP_TO_DATE;
    + if (mdev->state.pdsk <= D_OUTDATED && mdev->state.pdsk >= D_INCONSISTENT)
    + mdf |= MDF_PEER_OUT_DATED;
    + if (mdf != mdev->ldev->md.flags) {
    + mdev->ldev->md.flags = mdf;
    + drbd_md_mark_dirty(mdev);
    + }
    + if (os.disk < D_CONSISTENT && ns.disk >= D_CONSISTENT)
    + drbd_set_ed_uuid(mdev, mdev->ldev->md.uuid[UI_CURRENT]);
    + put_ldev(mdev);
    + }
    +
    + /* Peer was forced D_UP_TO_DATE & R_PRIMARY, consider to resync */
    + if (os.disk == D_INCONSISTENT && os.pdsk == D_INCONSISTENT &&
    + os.peer == R_SECONDARY && ns.peer == R_PRIMARY)
    + set_bit(CONSIDER_RESYNC, &mdev->flags);
    +
    + /* Receiver should clean up itself */
    + if (os.conn != C_DISCONNECTING && ns.conn == C_DISCONNECTING)
    + drbd_thread_stop_nowait(&mdev->receiver);
    +
    + /* Now the receiver finished cleaning up itself, it should die */
    + if (os.conn != C_STANDALONE && ns.conn == C_STANDALONE)
    + drbd_thread_stop_nowait(&mdev->receiver);
    +
    + /* Upon network failure, we need to restart the receiver. */
    + if (os.conn > C_TEAR_DOWN &&
    + ns.conn <= C_TEAR_DOWN && ns.conn >= C_TIMEOUT)
    + drbd_thread_restart_nowait(&mdev->receiver);
    +
    + ascw = kmalloc(sizeof(*ascw), GFP_ATOMIC);
    + if (ascw) {
    + ascw->os = os;
    + ascw->ns = ns;
    + ascw->flags = flags;
    + ascw->w.cb = w_after_state_ch;
    + ascw->done = done;
    + drbd_queue_work(&mdev->data.work, &ascw->w);
    + } else {
    + dev_warn(DEV, "Could not kmalloc an ascw\n");
    + }
    +
    + return rv;
    +}
    +
    +STATIC int w_after_state_ch(struct drbd_conf *mdev, struct drbd_work *w, int unused)
    +{
    + struct after_state_chg_work *ascw;
    +
    + ascw = (struct after_state_chg_work *) w;
    + after_state_ch(mdev, ascw->os, ascw->ns, ascw->flags);
    + if (ascw->flags & CS_WAIT_COMPLETE) {
    + D_ASSERT(ascw->done != NULL);
    + complete(ascw->done);
    + }
    + kfree(ascw);
    +
    + return 1;
    +}
    +
    +static void abw_start_sync(struct drbd_conf *mdev, int rv)
    +{
    + if (rv) {
    + dev_err(DEV, "Writing the bitmap failed not starting resync.\n");
    + _drbd_request_state(mdev, NS(conn, C_CONNECTED), CS_VERBOSE);
    + return;
    + }
    +
    + switch (mdev->state.conn) {
    + case C_STARTING_SYNC_T:
    + _drbd_request_state(mdev, NS(conn, C_WF_SYNC_UUID), CS_VERBOSE);
    + break;
    + case C_STARTING_SYNC_S:
    + drbd_start_resync(mdev, C_SYNC_SOURCE);
    + break;
    + }
    +}
    +
    +/**
    + * after_state_ch() - Perform after state change actions that may sleep
    + * @mdev: DRBD device.
    + * @os: old state.
    + * @ns: new state.
    + * @flags: Flags
    + */
    +STATIC void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
    + union drbd_state ns, enum chg_state_flags flags)
    +{
    + enum drbd_fencing_p fp;
    +
    + if (os.conn != C_CONNECTED && ns.conn == C_CONNECTED) {
    + clear_bit(CRASHED_PRIMARY, &mdev->flags);
    + if (mdev->p_uuid)
    + mdev->p_uuid[UI_FLAGS] &= ~((u64)2);
    + }
    +
    + fp = FP_DONT_CARE;
    + if (get_ldev(mdev)) {
    + fp = mdev->ldev->dc.fencing;
    + put_ldev(mdev);
    + }
    +
    + /* Inform userspace about the change... */
    + drbd_bcast_state(mdev, ns);
    +
    + if (!(os.role == R_PRIMARY && os.disk < D_UP_TO_DATE && os.pdsk < D_UP_TO_DATE) &&
    + (ns.role == R_PRIMARY && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE))
    + drbd_khelper(mdev, "pri-on-incon-degr");
    +
    + /* Here we have the actions that are performed after a
    + state change. This function might sleep */
    +
    + if (fp == FP_STONITH && ns.susp) {
    + /* case1: The outdate peer handler is successfull:
    + * case2: The connection was established again: */
    + if ((os.pdsk > D_OUTDATED && ns.pdsk <= D_OUTDATED) ||
    + (os.conn < C_CONNECTED && ns.conn >= C_CONNECTED)) {
    + tl_clear(mdev);
    + spin_lock_irq(&mdev->req_lock);
    + _drbd_set_state(_NS(mdev, susp, 0), CS_VERBOSE, NULL);
    + spin_unlock_irq(&mdev->req_lock);
    + }
    + }
    + /* Do not change the order of the if above and the two below... */
    + if (os.pdsk == D_DISKLESS && ns.pdsk > D_DISKLESS) { /* attach on the peer */
    + drbd_send_uuids(mdev);
    + drbd_send_state(mdev);
    + }
    + if (os.conn != C_WF_BITMAP_S && ns.conn == C_WF_BITMAP_S)
    + drbd_queue_bitmap_io(mdev, &drbd_send_bitmap, NULL, "send_bitmap (WFBitMapS)");
    +
    + /* Lost contact to peer's copy of the data */
    + if ((os.pdsk >= D_INCONSISTENT &&
    + os.pdsk != D_UNKNOWN &&
    + os.pdsk != D_OUTDATED)
    + && (ns.pdsk < D_INCONSISTENT ||
    + ns.pdsk == D_UNKNOWN ||
    + ns.pdsk == D_OUTDATED)) {
    + kfree(mdev->p_uuid);
    + mdev->p_uuid = NULL;
    + if (get_ldev(mdev)) {
    + if ((ns.role == R_PRIMARY || ns.peer == R_PRIMARY) &&
    + mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE) {
    + drbd_uuid_new_current(mdev);
    + drbd_send_uuids(mdev);
    + }
    + put_ldev(mdev);
    + }
    + }
    +
    + if (ns.pdsk < D_INCONSISTENT && get_ldev(mdev)) {
    + if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0)
    + drbd_uuid_new_current(mdev);
    +
    + /* D_DISKLESS Peer becomes secondary */
    + if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
    + drbd_al_to_on_disk_bm(mdev);
    + put_ldev(mdev);
    + }
    +
    + /* Last part of the attaching process ... */
    + if (ns.conn >= C_CONNECTED &&
    + os.disk == D_ATTACHING && ns.disk == D_NEGOTIATING) {
    + kfree(mdev->p_uuid); /* We expect to receive up-to-date UUIDs soon. */
    + mdev->p_uuid = NULL; /* ...to not use the old ones in the mean time */
    + drbd_send_sizes(mdev); /* to start sync... */
    + drbd_send_uuids(mdev);
    + drbd_send_state(mdev);
    + }
    +
    + /* We want to pause/continue resync, tell peer. */
    + if (ns.conn >= C_CONNECTED &&
    + ((os.aftr_isp != ns.aftr_isp) ||
    + (os.user_isp != ns.user_isp)))
    + drbd_send_state(mdev);
    +
    + /* In case one of the isp bits got set, suspend other devices. */
    + if ((!os.aftr_isp && !os.peer_isp && !os.user_isp) &&
    + (ns.aftr_isp || ns.peer_isp || ns.user_isp))
    + suspend_other_sg(mdev);
    +
    + /* Make sure the peer gets informed about eventual state
    + changes (ISP bits) while we were in WFReportParams. */
    + if (os.conn == C_WF_REPORT_PARAMS && ns.conn >= C_CONNECTED)
    + drbd_send_state(mdev);
    +
    + /* We are in the progress to start a full sync... */
    + if ((os.conn != C_STARTING_SYNC_T && ns.conn == C_STARTING_SYNC_T) ||
    + (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S))
    + drbd_queue_bitmap_io(mdev, &drbd_bmio_set_n_write, &abw_start_sync, "set_n_write from StartingSync");
    +
    + /* We are invalidating our self... */
    + if (os.conn < C_CONNECTED && ns.conn < C_CONNECTED &&
    + os.disk > D_INCONSISTENT && ns.disk == D_INCONSISTENT)
    + drbd_queue_bitmap_io(mdev, &drbd_bmio_set_n_write, NULL, "set_n_write from invalidate");
    +
    + if (os.disk > D_DISKLESS && ns.disk == D_DISKLESS) {
    + /* since get_ldev() only works as long as disk>=D_INCONSISTENT,
    + and it is D_DISKLESS here, local_cnt can only go down, it can
    + not increase... It will reach zero */
    + wait_event(mdev->misc_wait, !atomic_read(&mdev->local_cnt));
    +
    + drbd_rs_cancel_all(mdev);
    + mdev->rs_total = 0;
    + mdev->rs_failed = 0;
    + atomic_set(&mdev->rs_pending_cnt, 0);
    +
    + lc_destroy(mdev->resync);
    + mdev->resync = NULL;
    + lc_destroy(mdev->act_log);
    + mdev->act_log = NULL;
    + __no_warn(local,
    + drbd_free_bc(mdev->ldev);
    + mdev->ldev = NULL;);
    +
    + if (mdev->md_io_tmpp)
    + __free_page(mdev->md_io_tmpp);
    + }
    +
    + /* Disks got bigger while they were detached */
    + if (ns.disk > D_NEGOTIATING && ns.pdsk > D_NEGOTIATING &&
    + test_and_clear_bit(RESYNC_AFTER_NEG, &mdev->flags)) {
    + if (ns.conn == C_CONNECTED)
    + resync_after_online_grow(mdev);
    + }
    +
    + /* A resync finished or aborted, wake paused devices... */
    + if ((os.conn > C_CONNECTED && ns.conn <= C_CONNECTED) ||
    + (os.peer_isp && !ns.peer_isp) ||
    + (os.user_isp && !ns.user_isp))
    + resume_next_sg(mdev);
    +
    + /* Upon network connection, we need to start the received */
    + if (os.conn == C_STANDALONE && ns.conn == C_UNCONNECTED)
    + drbd_thread_start(&mdev->receiver);
    +
    + /* Terminate worker thread if we are unconfigured - it will be
    + restarted as needed... */
    + if (ns.disk == D_DISKLESS &&
    + ns.conn == C_STANDALONE &&
    + ns.role == R_SECONDARY) {
    + if (os.aftr_isp != ns.aftr_isp)
    + resume_next_sg(mdev);
    + /* set in __drbd_set_state, unless CONFIG_PENDING was set */
    + if (test_bit(DEVICE_DYING, &mdev->flags))
    + drbd_thread_stop_nowait(&mdev->worker);
    + }
    +
    + drbd_md_sync(mdev);
    +}
    +
    +
    +STATIC int drbd_thread_setup(void *arg)
    +{
    + struct drbd_thread *thi = (struct drbd_thread *) arg;
    + struct drbd_conf *mdev = thi->mdev;
    + unsigned long flags;
    + int retval;
    +
    +restart:
    + retval = thi->function(thi);
    +
    + spin_lock_irqsave(&thi->t_lock, flags);
    +
    + /* if the receiver has been "Exiting", the last thing it did
    + * was set the conn state to "StandAlone",
    + * if now a re-connect request comes in, conn state goes C_UNCONNECTED,
    + * and receiver thread will be "started".
    + * drbd_thread_start needs to set "Restarting" in that case.
    + * t_state check and assignement needs to be within the same spinlock,
    + * so either thread_start sees Exiting, and can remap to Restarting,
    + * or thread_start see None, and can proceed as normal.
    + */
    +
    + if (thi->t_state == Restarting) {
    + dev_info(DEV, "Restarting %s\n", current->comm);
    + thi->t_state = Running;
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    + goto restart;
    + }
    +
    + thi->task = NULL;
    + thi->t_state = None;
    + smp_mb();
    + complete(&thi->stop);
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    +
    + dev_info(DEV, "Terminating %s\n", current->comm);
    +
    + /* Release mod reference taken when thread was started */
    + module_put(THIS_MODULE);
    + return retval;
    +}
    +
    +STATIC void drbd_thread_init(struct drbd_conf *mdev, struct drbd_thread *thi,
    + int (*func) (struct drbd_thread *))
    +{
    + spin_lock_init(&thi->t_lock);
    + thi->task = NULL;
    + thi->t_state = None;
    + thi->function = func;
    + thi->mdev = mdev;
    +}
    +
    +int drbd_thread_start(struct drbd_thread *thi)
    +{
    + struct drbd_conf *mdev = thi->mdev;
    + struct task_struct *nt;
    + unsigned long flags;
    +
    + const char *me =
    + thi == &mdev->receiver ? "receiver" :
    + thi == &mdev->asender ? "asender" :
    + thi == &mdev->worker ? "worker" : "NONSENSE";
    +
    + /* is used from state engine doing drbd_thread_stop_nowait,
    + * while holding the req lock irqsave */
    + spin_lock_irqsave(&thi->t_lock, flags);
    +
    + switch (thi->t_state) {
    + case None:
    + dev_info(DEV, "Starting %s thread (from %s [%d])\n",
    + me, current->comm, current->pid);
    +
    + /* Get ref on module for thread - this is released when thread exits */
    + if (!try_module_get(THIS_MODULE)) {
    + dev_err(DEV, "Failed to get module reference in drbd_thread_start\n");
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    + return FALSE;
    + }
    +
    + D_ASSERT(thi->task == NULL);
    + thi->reset_cpu_mask = 1;
    + thi->t_state = Running;
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    + flush_signals(current); /* otherw. may get -ERESTARTNOINTR */
    +
    + nt = kthread_create(drbd_thread_setup, (void *) thi,
    + "drbd%d_%s", mdev_to_minor(mdev), me);
    +
    + if (IS_ERR(nt)) {
    + dev_err(DEV, "Couldn't start thread\n");
    +
    + module_put(THIS_MODULE);
    + return FALSE;
    + }
    + spin_lock(&thi->t_lock);
    + thi->task = nt;
    + thi->t_state = Running;
    + spin_unlock(&thi->t_lock);
    + wake_up_process(nt);
    + break;
    + case Exiting:
    + thi->t_state = Restarting;
    + dev_info(DEV, "Restarting %s thread (from %s [%d])\n",
    + me, current->comm, current->pid);
    + /* fall through */
    + case Running:
    + case Restarting:
    + default:
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    + break;
    + }
    +
    + return TRUE;
    +}
    +
    +
    +void _drbd_thread_stop(struct drbd_thread *thi, int restart, int wait)
    +{
    + unsigned long flags;
    + enum drbd_thread_state ns = restart ? Restarting : Exiting;
    +
    + /* may be called from state engine, holding the req lock irqsave */
    + spin_lock_irqsave(&thi->t_lock, flags);
    +
    + if (thi->t_state == None) {
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    + if (restart)
    + drbd_thread_start(thi);
    + return;
    + }
    +
    + if (thi->t_state != ns) {
    + if (thi->task == NULL) {
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    + return;
    + }
    +
    + thi->t_state = ns;
    + smp_mb();
    + init_completion(&thi->stop);
    + if (thi->task != current)
    + force_sig(DRBD_SIGKILL, thi->task);
    +
    + }
    +
    + spin_unlock_irqrestore(&thi->t_lock, flags);
    +
    + if (wait)
    + wait_for_completion(&thi->stop);
    +}
    +
    +#ifdef CONFIG_SMP
    +/**
    + * drbd_calc_cpu_mask() - Generate CPU masks, spread over all CPUs
    + * @mdev: DRBD device.
    + *
    + * Forces all threads of a device onto the same CPU. This is benificial for
    + * DRBD's performance. May be overwritten by user's configuration.
    + */
    +cpumask_t drbd_calc_cpu_mask(struct drbd_conf *mdev)
    +{
    + int sv, cpu;
    + cpumask_t av_cpu_m;
    +
    + if (cpus_weight(mdev->cpu_mask))
    + return mdev->cpu_mask;
    +
    + av_cpu_m = cpu_online_map;
    + sv = mdev_to_minor(mdev) % cpus_weight(av_cpu_m);
    +
    + for_each_cpu_mask(cpu, av_cpu_m) {
    + if (sv-- == 0)
    + return cpumask_of_cpu(cpu);
    + }
    +
    + /* some kernel versions "forget" to add the (cpumask_t) typecast
    + * to that macro, which results in "parse error before '{'" ;-> */
    + return (cpumask_t) CPU_MASK_ALL; /* Never reached. */
    +}
    +
    +/**
    + * drbd_thread_current_set_cpu() - modifies the cpu mask of the _current_ thread
    + * @mdev: DRBD device.
    + *
    + * call in the "main loop" of _all_ threads, no need for any mutex, current won't die
    + * prematurely.
    + */
    +void drbd_thread_current_set_cpu(struct drbd_conf *mdev)
    +{
    + struct task_struct *p = current;
    + struct drbd_thread *thi =
    + p == mdev->asender.task ? &mdev->asender :
    + p == mdev->receiver.task ? &mdev->receiver :
    + p == mdev->worker.task ? &mdev->worker :
    + NULL;
    + ERR_IF(thi == NULL)
    + return;
    + if (!thi->reset_cpu_mask)
    + return;
    + thi->reset_cpu_mask = 0;
    + /* preempt_disable();
    + Thas was a kernel that warned about a call to smp_processor_id() while preemt
    + was not disabled. It seems that this was fixed in manline. */
    + set_cpus_allowed(p, mdev->cpu_mask);
    + /* preempt_enable(); */
    +}
    +#endif
    +
    +/* the appropriate socket mutex must be held already */
    +int _drbd_send_cmd(struct drbd_conf *mdev, struct socket *sock,
    + enum drbd_packets cmd, struct p_header *h,
    + size_t size, unsigned msg_flags)
    +{
    + int sent, ok;
    +
    + ERR_IF(!h) return FALSE;
    + ERR_IF(!size) return FALSE;
    +
    + h->magic = BE_DRBD_MAGIC;
    + h->command = cpu_to_be16(cmd);
    + h->length = cpu_to_be16(size-sizeof(struct p_header));
    +
    + trace_drbd_packet(mdev, sock, 0, (void *)h, __FILE__, __LINE__);
    + sent = drbd_send(mdev, sock, h, size, msg_flags);
    +
    + ok = (sent == size);
    + if (!ok)
    + dev_err(DEV, "short sent %s size=%d sent=%d\n",
    + cmdname(cmd), (int)size, sent);
    + return ok;
    +}
    +
    +/* don't pass the socket. we may only look at it
    + * when we hold the appropriate socket mutex.
    + */
    +int drbd_send_cmd(struct drbd_conf *mdev, int use_data_socket,
    + enum drbd_packets cmd, struct p_header *h, size_t size)
    +{
    + int ok = 0;
    + struct socket *sock;
    +
    + if (use_data_socket) {
    + mutex_lock(&mdev->data.mutex);
    + sock = mdev->data.socket;
    + } else {
    + mutex_lock(&mdev->meta.mutex);
    + sock = mdev->meta.socket;
    + }
    +
    + /* drbd_disconnect() could have called drbd_free_sock()
    + * while we were waiting in down()... */
    + if (likely(sock != NULL))
    + ok = _drbd_send_cmd(mdev, sock, cmd, h, size, 0);
    +
    + if (use_data_socket)
    + mutex_unlock(&mdev->data.mutex);
    + else
    + mutex_unlock(&mdev->meta.mutex);
    + return ok;
    +}
    +
    +int drbd_send_cmd2(struct drbd_conf *mdev, enum drbd_packets cmd, char *data,
    + size_t size)
    +{
    + struct p_header h;
    + int ok;
    +
    + h.magic = BE_DRBD_MAGIC;
    + h.command = cpu_to_be16(cmd);
    + h.length = cpu_to_be16(size);
    +
    + if (!drbd_get_data_sock(mdev))
    + return 0;
    +
    + trace_drbd_packet(mdev, mdev->data.socket, 0, (void *)&h, __FILE__, __LINE__);
    +
    + ok = (sizeof(h) ==
    + drbd_send(mdev, mdev->data.socket, &h, sizeof(h), 0));
    + ok = ok && (size ==
    + drbd_send(mdev, mdev->data.socket, data, size, 0));
    +
    + drbd_put_data_sock(mdev);
    +
    + return ok;
    +}
    +
    +int drbd_send_sync_param(struct drbd_conf *mdev, struct syncer_conf *sc)
    +{
    + struct p_rs_param_89 *p;
    + struct socket *sock;
    + int size, rv;
    + const int apv = mdev->agreed_pro_version;
    +
    + size = apv <= 87 ? sizeof(struct p_rs_param)
    + : apv == 88 ? sizeof(struct p_rs_param)
    + + strlen(mdev->sync_conf.verify_alg) + 1
    + : /* 89 */ sizeof(struct p_rs_param_89);
    +
    + /* used from admin command context and receiver/worker context.
    + * to avoid kmalloc, grab the socket right here,
    + * then use the pre-allocated sbuf there */
    + mutex_lock(&mdev->data.mutex);
    + sock = mdev->data.socket;
    +
    + if (likely(sock != NULL)) {
    + enum drbd_packets cmd = apv >= 89 ? P_SYNC_PARAM89 : P_SYNC_PARAM;
    +
    + p = &mdev->data.sbuf.rs_param_89;
    +
    + /* initialize verify_alg and csums_alg */
    + memset(p->verify_alg, 0, 2 * SHARED_SECRET_MAX);
    +
    + p->rate = cpu_to_be32(sc->rate);
    +
    + if (apv >= 88)
    + strcpy(p->verify_alg, mdev->sync_conf.verify_alg);
    + if (apv >= 89)
    + strcpy(p->csums_alg, mdev->sync_conf.csums_alg);
    +
    + rv = _drbd_send_cmd(mdev, sock, cmd, &p->head, size, 0);
    + } else
    + rv = 0; /* not ok */
    +
    + mutex_unlock(&mdev->data.mutex);
    +
    + return rv;
    +}
    +
    +int drbd_send_protocol(struct drbd_conf *mdev)
    +{
    + struct p_protocol *p;
    + int size, rv;
    +
    + size = sizeof(struct p_protocol);
    +
    + if (mdev->agreed_pro_version >= 87)
    + size += strlen(mdev->net_conf->integrity_alg) + 1;
    +
    + p = kmalloc(size, GFP_KERNEL);
    + if (p == NULL)
    + return 0;
    +
    + p->protocol = cpu_to_be32(mdev->net_conf->wire_protocol);
    + p->after_sb_0p = cpu_to_be32(mdev->net_conf->after_sb_0p);
    + p->after_sb_1p = cpu_to_be32(mdev->net_conf->after_sb_1p);
    + p->after_sb_2p = cpu_to_be32(mdev->net_conf->after_sb_2p);
    + p->want_lose = cpu_to_be32(mdev->net_conf->want_lose);
    + p->two_primaries = cpu_to_be32(mdev->net_conf->two_primaries);
    +
    + if (mdev->agreed_pro_version >= 87)
    + strcpy(p->integrity_alg, mdev->net_conf->integrity_alg);
    +
    + rv = drbd_send_cmd(mdev, USE_DATA_SOCKET, P_PROTOCOL,
    + (struct p_header *)p, size);
    + kfree(p);
    + return rv;
    +}
    +
    +int _drbd_send_uuids(struct drbd_conf *mdev, u64 uuid_flags)
    +{
    + struct p_uuids p;
    + int i;
    +
    + if (!get_ldev_if_state(mdev, D_NEGOTIATING))
    + return 1;
    +
    + for (i = UI_CURRENT; i < UI_SIZE; i++)
    + p.uuid[i] = mdev->ldev ? cpu_to_be64(mdev->ldev->md.uuid[i]) : 0;
    +
    + mdev->comm_bm_set = drbd_bm_total_weight(mdev);
    + p.uuid[UI_SIZE] = cpu_to_be64(mdev->comm_bm_set);
    + uuid_flags |= mdev->net_conf->want_lose ? 1 : 0;
    + uuid_flags |= test_bit(CRASHED_PRIMARY, &mdev->flags) ? 2 : 0;
    + uuid_flags |= mdev->new_state_tmp.disk == D_INCONSISTENT ? 4 : 0;
    + p.uuid[UI_FLAGS] = cpu_to_be64(uuid_flags);
    +
    + put_ldev(mdev);
    +
    + return drbd_send_cmd(mdev, USE_DATA_SOCKET, P_UUIDS,
    + (struct p_header *)&p, sizeof(p));
    +}
    +
    +int drbd_send_uuids(struct drbd_conf *mdev)
    +{
    + return _drbd_send_uuids(mdev, 0);
    +}
    +
    +int drbd_send_uuids_skip_initial_sync(struct drbd_conf *mdev)
    +{
    + return _drbd_send_uuids(mdev, 8);
    +}
    +
    +
    +int drbd_send_sync_uuid(struct drbd_conf *mdev, u64 val)
    +{
    + struct p_rs_uuid p;
    +
    + p.uuid = cpu_to_be64(val);
    +
    + return drbd_send_cmd(mdev, USE_DATA_SOCKET, P_SYNC_UUID,
    + (struct p_header *)&p, sizeof(p));
    +}
    +
    +int drbd_send_sizes(struct drbd_conf *mdev)
    +{
    + struct p_sizes p;
    + sector_t d_size, u_size;
    + int q_order_type;
    + int ok;
    +
    + if (get_ldev_if_state(mdev, D_NEGOTIATING)) {
    + D_ASSERT(mdev->ldev->backing_bdev);
    + d_size = drbd_get_max_capacity(mdev->ldev);
    + u_size = mdev->ldev->dc.disk_size;
    + q_order_type = drbd_queue_order_type(mdev);
    + p.queue_order_type = cpu_to_be32(drbd_queue_order_type(mdev));
    + put_ldev(mdev);
    + } else {
    + d_size = 0;
    + u_size = 0;
    + q_order_type = QUEUE_ORDERED_NONE;
    + }
    +
    + p.d_size = cpu_to_be64(d_size);
    + p.u_size = cpu_to_be64(u_size);
    + p.c_size = cpu_to_be64(drbd_get_capacity(mdev->this_bdev));
    + p.max_segment_size = cpu_to_be32(mdev->rq_queue->max_segment_size);
    + p.queue_order_type = cpu_to_be32(q_order_type);
    +
    + ok = drbd_send_cmd(mdev, USE_DATA_SOCKET, P_SIZES,
    + (struct p_header *)&p, sizeof(p));
    + return ok;
    +}
    +
    +/**
    + * drbd_send_state() - Sends the drbd state to the peer
    + * @mdev: DRBD device.
    + */
    +int drbd_send_state(struct drbd_conf *mdev)
    +{
    + struct socket *sock;
    + struct p_state p;
    + int ok = 0;
    +
    + /* Grab state lock so we wont send state if we're in the middle
    + * of a cluster wide state change on another thread */
    + drbd_state_lock(mdev);
    +
    + mutex_lock(&mdev->data.mutex);
    +
    + p.state = cpu_to_be32(mdev->state.i); /* Within the send mutex */
    + sock = mdev->data.socket;
    +
    + if (likely(sock != NULL)) {
    + ok = _drbd_send_cmd(mdev, sock, P_STATE,
    + (struct p_header *)&p, sizeof(p), 0);
    + }
    +
    + mutex_unlock(&mdev->data.mutex);
    +
    + drbd_state_unlock(mdev);
    + return ok;
    +}
    +
    +int drbd_send_state_req(struct drbd_conf *mdev,
    + union drbd_state mask, union drbd_state val)
    +{
    + struct p_req_state p;
    +
    + p.mask = cpu_to_be32(mask.i);
    + p.val = cpu_to_be32(val.i);
    +
    + return drbd_send_cmd(mdev, USE_DATA_SOCKET, P_STATE_CHG_REQ,
    + (struct p_header *)&p, sizeof(p));
    +}
    +
    +int drbd_send_sr_reply(struct drbd_conf *mdev, int retcode)
    +{
    + struct p_req_state_reply p;
    +
    + p.retcode = cpu_to_be32(retcode);
    +
    + return drbd_send_cmd(mdev, USE_META_SOCKET, P_STATE_CHG_REPLY,
    + (struct p_header *)&p, sizeof(p));
    +}
    +
    +int fill_bitmap_rle_bits(struct drbd_conf *mdev,
    + struct p_compressed_bm *p,
    + struct bm_xfer_ctx *c)
    +{
    + struct bitstream bs;
    + unsigned long plain_bits;
    + unsigned long tmp;
    + unsigned long rl;
    + unsigned len;
    + unsigned toggle;
    + int bits;
    +
    + /* may we use this feature? */
    + if ((mdev->sync_conf.use_rle_encoding == 0) ||
    + (mdev->agreed_pro_version < 90))
    + return 0;
    +
    + if (c->bit_offset >= c->bm_bits)
    + return 0; /* nothing to do. */
    +
    + /* use at most thus many bytes */
    + bitstream_init(&bs, p->code, BM_PACKET_VLI_BYTES_MAX, 0);
    + memset(p->code, 0, BM_PACKET_VLI_BYTES_MAX);
    + /* plain bits covered in this code string */
    + plain_bits = 0;
    +
    + /* p->encoding & 0x80 stores whether the first run length is set.
    + * bit offset is implicit.
    + * start with toggle == 2 to be able to tell the first iteration */
    + toggle = 2;
    +
    + /* see how much plain bits we can stuff into one packet
    + * using RLE and VLI. */
    + do {
    + tmp = (toggle == 0) ? _drbd_bm_find_next_zero(mdev, c->bit_offset)
    + : _drbd_bm_find_next(mdev, c->bit_offset);
    + if (tmp == -1UL)
    + tmp = c->bm_bits;
    + rl = tmp - c->bit_offset;
    +
    + if (toggle == 2) { /* first iteration */
    + if (rl == 0) {
    + /* the first checked bit was set,
    + * store start value, */
    + DCBP_set_start(p, 1);
    + /* but skip encoding of zero run length */
    + toggle = !toggle;
    + continue;
    + }
    + DCBP_set_start(p, 0);
    + }
    +
    + /* paranoia: catch zero runlength.
    + * can only happen if bitmap is modified while we scan it. */
    + if (rl == 0) {
    + dev_err(DEV, "unexpected zero runlength while encoding bitmap "
    + "t:%u bo:%lu\n", toggle, c->bit_offset);
    + return -1;
    + }
    +
    + bits = vli_encode_bits(&bs, rl);
    + if (bits == -ENOBUFS) /* buffer full */
    + break;
    + if (bits <= 0) {
    + dev_err(DEV, "error while encoding bitmap: %d\n", bits);
    + return 0;
    + }
    +
    + toggle = !toggle;
    + plain_bits += rl;
    + c->bit_offset = tmp;
    + } while (c->bit_offset < c->bm_bits);
    +
    + len = bs.cur.b - p->code + !!bs.cur.bit;
    +
    + if (plain_bits < (len << 3)) {
    + /* incompressible with this method.
    + * we need to rewind both word and bit position. */
    + c->bit_offset -= plain_bits;
    + bm_xfer_ctx_bit_to_word_offset(c);
    + c->bit_offset = c->word_offset * BITS_PER_LONG;
    + return 0;
    + }
    +
    + /* RLE + VLI was able to compress it just fine.
    + * update c->word_offset. */
    + bm_xfer_ctx_bit_to_word_offset(c);
    +
    + /* store pad_bits */
    + DCBP_set_pad_bits(p, (8 - bs.cur.bit) & 0x7);
    +
    + return len;
    +}
    +
    +enum { OK, FAILED, DONE }
    +send_bitmap_rle_or_plain(struct drbd_conf *mdev,
    + struct p_header *h, struct bm_xfer_ctx *c)
    +{
    + struct p_compressed_bm *p = (void*)h;
    + unsigned long num_words;
    + int len;
    + int ok;
    +
    + len = fill_bitmap_rle_bits(mdev, p, c);
    +
    + if (len < 0)
    + return FAILED;
    +
    + if (len) {
    + DCBP_set_code(p, RLE_VLI_Bits);
    + ok = _drbd_send_cmd(mdev, mdev->data.socket, P_COMPRESSED_BITMAP, h,
    + sizeof(*p) + len, 0);
    +
    + c->packets[0]++;
    + c->bytes[0] += sizeof(*p) + len;
    +
    + if (c->bit_offset >= c->bm_bits)
    + len = 0; /* DONE */
    + } else {
    + /* was not compressible.
    + * send a buffer full of plain text bits instead. */
    + num_words = min_t(size_t, BM_PACKET_WORDS, c->bm_words - c->word_offset);
    + len = num_words * sizeof(long);
    + if (len)
    + drbd_bm_get_lel(mdev, c->word_offset, num_words, (unsigned long*)h->payload);
    + ok = _drbd_send_cmd(mdev, mdev->data.socket, P_BITMAP,
    + h, sizeof(struct p_header) + len, 0);
    + c->word_offset += num_words;
    + c->bit_offset = c->word_offset * BITS_PER_LONG;
    +
    + c->packets[1]++;
    + c->bytes[1] += sizeof(struct p_header) + len;
    +
    + if (c->bit_offset > c->bm_bits)
    + c->bit_offset = c->bm_bits;
    + }
    + ok = ok ? ((len == 0) ? DONE : OK) : FAILED;
    +
    + if (ok == DONE)
    + INFO_bm_xfer_stats(mdev, "send", c);
    + return ok;
    +}
    +
    +/* See the comment at receive_bitmap() */
    +int _drbd_send_bitmap(struct drbd_conf *mdev)
    +{
    + struct bm_xfer_ctx c;
    + struct p_header *p;
    + int ret;
    +
    + ERR_IF(!mdev->bitmap) return FALSE;
    +
    + /* maybe we should use some per thread scratch page,
    + * and allocate that during initial device creation? */
    + p = (struct p_header *) __get_free_page(GFP_NOIO);
    + if (!p) {
    + dev_err(DEV, "failed to allocate one page buffer in %s\n", __func__);
    + return FALSE;
    + }
    +
    + if (get_ldev(mdev)) {
    + if (drbd_md_test_flag(mdev->ldev, MDF_FULL_SYNC)) {
    + dev_info(DEV, "Writing the whole bitmap, MDF_FullSync was set.\n");
    + drbd_bm_set_all(mdev);
    + if (drbd_bm_write(mdev)) {
    + /* write_bm did fail! Leave full sync flag set in Meta P_DATA
    + * but otherwise process as per normal - need to tell other
    + * side that a full resync is required! */
    + dev_err(DEV, "Failed to write bitmap to disk!\n");
    + } else {
    + drbd_md_clear_flag(mdev, MDF_FULL_SYNC);
    + drbd_md_sync(mdev);
    + }
    + }
    + put_ldev(mdev);
    + }
    +
    + c = (struct bm_xfer_ctx) {
    + .bm_bits = drbd_bm_bits(mdev),
    + .bm_words = drbd_bm_words(mdev),
    + };
    +
    + do {
    + ret = send_bitmap_rle_or_plain(mdev, p, &c);
    + } while (ret == OK);
    +
    + free_page((unsigned long) p);
    + return (ret == DONE);
    +}
    +
    +int drbd_send_bitmap(struct drbd_conf *mdev)
    +{
    + int err;
    +
    + if (!drbd_get_data_sock(mdev))
    + return -1;
    + err = !_drbd_send_bitmap(mdev);
    + drbd_put_data_sock(mdev);
    + return err;
    +}
    +
    +int drbd_send_b_ack(struct drbd_conf *mdev, u32 barrier_nr, u32 set_size)
    +{
    + int ok;
    + struct p_barrier_ack p;
    +
    + p.barrier = barrier_nr;
    + p.set_size = cpu_to_be32(set_size);
    +
    + if (mdev->state.conn < C_CONNECTED)
    + return FALSE;
    + ok = drbd_send_cmd(mdev, USE_META_SOCKET, P_BARRIER_ACK,
    + (struct p_header *)&p, sizeof(p));
    + return ok;
    +}
    +
    +/**
    + * _drbd_send_ack() - Sends an ack packet
    + * @mdev: DRBD device.
    + * @cmd: Packet command code.
    + * @sector: sector, needs to be in big endian byte order
    + * @blksize: size in byte, needs to be in big endian byte order
    + * @block_id: Id, big endian byte order
    + */
    +STATIC int _drbd_send_ack(struct drbd_conf *mdev, enum drbd_packets cmd,
    + u64 sector,
    + u32 blksize,
    + u64 block_id)
    +{
    + int ok;
    + struct p_block_ack p;
    +
    + p.sector = sector;
    + p.block_id = block_id;
    + p.blksize = blksize;
    + p.seq_num = cpu_to_be32(atomic_add_return(1, &mdev->packet_seq));
    +
    + if (!mdev->meta.socket || mdev->state.conn < C_CONNECTED)
    + return FALSE;
    + ok = drbd_send_cmd(mdev, USE_META_SOCKET, cmd,
    + (struct p_header *)&p, sizeof(p));
    + return ok;
    +}
    +
    +int drbd_send_ack_dp(struct drbd_conf *mdev, enum drbd_packets cmd,
    + struct p_data *dp)
    +{
    + const int header_size = sizeof(struct p_data)
    + - sizeof(struct p_header);
    + int data_size = ((struct p_header *)dp)->length - header_size;
    +
    + return _drbd_send_ack(mdev, cmd, dp->sector, cpu_to_be32(data_size),
    + dp->block_id);
    +}
    +
    +int drbd_send_ack_rp(struct drbd_conf *mdev, enum drbd_packets cmd,
    + struct p_block_req *rp)
    +{
    + return _drbd_send_ack(mdev, cmd, rp->sector, rp->blksize, rp->block_id);
    +}
    +
    +/**
    + * drbd_send_ack() - Sends an ack packet
    + * @mdev: DRBD device.
    + * @cmd: Packet command code.
    + * @e: Epoch entry.
    + */
    +int drbd_send_ack(struct drbd_conf *mdev,
    + enum drbd_packets cmd, struct drbd_epoch_entry *e)
    +{
    + return _drbd_send_ack(mdev, cmd,
    + cpu_to_be64(e->sector),
    + cpu_to_be32(e->size),
    + e->block_id);
    +}
    +
    +/* This function misuses the block_id field to signal if the blocks
    + * are is sync or not. */
    +int drbd_send_ack_ex(struct drbd_conf *mdev, enum drbd_packets cmd,
    + sector_t sector, int blksize, u64 block_id)
    +{
    + return _drbd_send_ack(mdev, cmd,
    + cpu_to_be64(sector),
    + cpu_to_be32(blksize),
    + cpu_to_be64(block_id));
    +}
    +
    +int drbd_send_drequest(struct drbd_conf *mdev, int cmd,
    + sector_t sector, int size, u64 block_id)
    +{
    + int ok;
    + struct p_block_req p;
    +
    + p.sector = cpu_to_be64(sector);
    + p.block_id = block_id;
    + p.blksize = cpu_to_be32(size);
    +
    + ok = drbd_send_cmd(mdev, USE_DATA_SOCKET, cmd,
    + (struct p_header *)&p, sizeof(p));
    + return ok;
    +}
    +
    +int drbd_send_drequest_csum(struct drbd_conf *mdev,
    + sector_t sector, int size,
    + void *digest, int digest_size,
    + enum drbd_packets cmd)
    +{
    + int ok;
    + struct p_block_req p;
    +
    + p.sector = cpu_to_be64(sector);
    + p.block_id = BE_DRBD_MAGIC + 0xbeef;
    + p.blksize = cpu_to_be32(size);
    +
    + p.head.magic = BE_DRBD_MAGIC;
    + p.head.command = cpu_to_be16(cmd);
    + p.head.length = cpu_to_be16(sizeof(p) - sizeof(struct p_header) + digest_size);
    +
    + mutex_lock(&mdev->data.mutex);
    +
    + ok = (sizeof(p) == drbd_send(mdev, mdev->data.socket, &p, sizeof(p), 0));
    + ok = ok && (digest_size == drbd_send(mdev, mdev->data.socket, digest, digest_size, 0));
    +
    + mutex_unlock(&mdev->data.mutex);
    +
    + return ok;
    +}
    +
    +int drbd_send_ov_request(struct drbd_conf *mdev, sector_t sector, int size)
    +{
    + int ok;
    + struct p_block_req p;
    +
    + p.sector = cpu_to_be64(sector);
    + p.block_id = BE_DRBD_MAGIC + 0xbabe;
    + p.blksize = cpu_to_be32(size);
    +
    + ok = drbd_send_cmd(mdev, USE_DATA_SOCKET, P_OV_REQUEST,
    + (struct p_header *)&p, sizeof(p));
    + return ok;
    +}
    +
    +/* called on sndtimeo
    + * returns FALSE if we should retry,
    + * TRUE if we think connection is dead
    + */
    +STATIC int we_should_drop_the_connection(struct drbd_conf *mdev, struct socket *sock)
    +{
    + int drop_it;
    + /* long elapsed = (long)(jiffies - mdev->last_received); */
    +
    + drop_it = mdev->meta.socket == sock
    + || !mdev->asender.task
    + || get_t_state(&mdev->asender) != Running
    + || mdev->state.conn < C_CONNECTED;
    +
    + if (drop_it)
    + return TRUE;
    +
    + drop_it = !--mdev->ko_count;
    + if (!drop_it) {
    + dev_err(DEV, "[%s/%d] sock_sendmsg time expired, ko = %u\n",
    + current->comm, current->pid, mdev->ko_count);
    + request_ping(mdev);
    + }
    +
    + return drop_it; /* && (mdev->state == R_PRIMARY) */;
    +}
    +
    +/* The idea of sendpage seems to be to put some kind of reference
    + * to the page into the skb, and to hand it over to the NIC. In
    + * this process get_page() gets called.
    + *
    + * As soon as the page was really sent over the network put_page()
    + * gets called by some part of the network layer. [ NIC driver? ]
    + *
    + * [ get_page() / put_page() increment/decrement the count. If count
    + * reaches 0 the page will be freed. ]
    + *
    + * This works nicely with pages from FSs.
    + * But this means that in protocol A we might signal IO completion too early!
    + *
    + * In order not to corrupt data during a resync we must make sure
    + * that we do not reuse our own buffer pages (EEs) to early, therefore
    + * we have the net_ee list.
    + *
    + * XFS seems to have problems, still, it submits pages with page_count == 0!
    + * As a workaround, we disable sendpage on pages
    + * with page_count == 0 or PageSlab.
    + */
    +STATIC int _drbd_no_send_page(struct drbd_conf *mdev, struct page *page,
    + int offset, size_t size)
    +{
    + int sent = drbd_send(mdev, mdev->data.socket, kmap(page) + offset, size, 0);
    + kunmap(page);
    + if (sent == size)
    + mdev->send_cnt += size>>9;
    + return sent == size;
    +}
    +
    +int _drbd_send_page(struct drbd_conf *mdev, struct page *page,
    + int offset, size_t size)
    +{
    + mm_segment_t oldfs = get_fs();
    + int sent, ok;
    + int len = size;
    +
    + /* e.g. XFS meta- & log-data is in slab pages, which have a
    + * page_count of 0 and/or have PageSlab() set.
    + * we cannot use send_page for those, as that does get_page();
    + * put_page(); and would cause either a VM_BUG directly, or
    + * __page_cache_release a page that would actually still be referenced
    + * by someone, leading to some obscure delayed Oops somewhere else. */
    + if (disable_sendpage || (page_count(page) < 1) || PageSlab(page))
    + return _drbd_no_send_page(mdev, page, offset, size);
    +
    + drbd_update_congested(mdev);
    + set_fs(KERNEL_DS);
    + do {
    + sent = mdev->data.socket->ops->sendpage(mdev->data.socket, page,
    + offset, len,
    + MSG_NOSIGNAL);
    + if (sent == -EAGAIN) {
    + if (we_should_drop_the_connection(mdev,
    + mdev->data.socket))
    + break;
    + else
    + continue;
    + }
    + if (sent <= 0) {
    + dev_warn(DEV, "%s: size=%d len=%d sent=%d\n",
    + __func__, (int)size, len, sent);
    + break;
    + }
    + len -= sent;
    + offset += sent;
    + } while (len > 0 /* THINK && mdev->cstate >= C_CONNECTED*/);
    + set_fs(oldfs);
    + clear_bit(NET_CONGESTED, &mdev->flags);
    +
    + ok = (len == 0);
    + if (likely(ok))
    + mdev->send_cnt += size>>9;
    + return ok;
    +}
    +
    +static int _drbd_send_bio(struct drbd_conf *mdev, struct bio *bio)
    +{
    + struct bio_vec *bvec;
    + int i;
    + __bio_for_each_segment(bvec, bio, i, 0) {
    + if (!_drbd_no_send_page(mdev, bvec->bv_page,
    + bvec->bv_offset, bvec->bv_len))
    + return 0;
    + }
    + return 1;
    +}
    +
    +static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
    +{
    + struct bio_vec *bvec;
    + int i;
    + __bio_for_each_segment(bvec, bio, i, 0) {
    + if (!_drbd_send_page(mdev, bvec->bv_page,
    + bvec->bv_offset, bvec->bv_len))
    + return 0;
    + }
    +
    + return 1;
    +}
    +
    +/* Used to send write requests
    + * R_PRIMARY -> Peer (P_DATA)
    + */
    +int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
    +{
    + int ok = 1;
    + struct p_data p;
    + unsigned int dp_flags = 0;
    + void *dgb;
    + int dgs;
    +
    + if (!drbd_get_data_sock(mdev))
    + return 0;
    +
    + dgs = (mdev->agreed_pro_version >= 87 && mdev->integrity_w_tfm) ?
    + crypto_hash_digestsize(mdev->integrity_w_tfm) : 0;
    +
    + p.head.magic = BE_DRBD_MAGIC;
    + p.head.command = cpu_to_be16(P_DATA);
    + p.head.length =
    + cpu_to_be16(sizeof(p) - sizeof(struct p_header) + dgs + req->size);
    +
    + p.sector = cpu_to_be64(req->sector);
    + p.block_id = (unsigned long)req;
    + p.seq_num = cpu_to_be32(req->seq_num =
    + atomic_add_return(1, &mdev->packet_seq));
    + dp_flags = 0;
    +
    + /* NOTE: no need to check if barriers supported here as we would
    + * not pass the test in make_request_common in that case
    + */
    + if (bio_barrier(req->master_bio))
    + dp_flags |= DP_HARDBARRIER;
    + if (bio_sync(req->master_bio))
    + dp_flags |= DP_RW_SYNC;
    + if (mdev->state.conn >= C_SYNC_SOURCE &&
    + mdev->state.conn <= C_PAUSED_SYNC_T)
    + dp_flags |= DP_MAY_SET_IN_SYNC;
    +
    + p.dp_flags = cpu_to_be32(dp_flags);
    + trace_drbd_packet(mdev, mdev->data.socket, 0, (void *)&p, __FILE__, __LINE__);
    + set_bit(UNPLUG_REMOTE, &mdev->flags);
    + ok = (sizeof(p) ==
    + drbd_send(mdev, mdev->data.socket, &p, sizeof(p), MSG_MORE));
    + if (ok && dgs) {
    + dgb = mdev->int_dig_out;
    + drbd_csum(mdev, mdev->integrity_w_tfm, req->master_bio, dgb);
    + ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
    + }
    + if (ok) {
    + if (mdev->net_conf->wire_protocol == DRBD_PROT_A)
    + ok = _drbd_send_bio(mdev, req->master_bio);
    + else
    + ok = _drbd_send_zc_bio(mdev, req->master_bio);
    + }
    +
    + drbd_put_data_sock(mdev);
    + return ok;
    +}
    +
    +/* answer packet, used to send data back for read requests:
    + * Peer -> (diskless) R_PRIMARY (P_DATA_REPLY)
    + * C_SYNC_SOURCE -> C_SYNC_TARGET (P_RS_DATA_REPLY)
    + */
    +int drbd_send_block(struct drbd_conf *mdev, enum drbd_packets cmd,
    + struct drbd_epoch_entry *e)
    +{
    + int ok;
    + struct p_data p;
    + void *dgb;
    + int dgs;
    +
    + dgs = (mdev->agreed_pro_version >= 87 && mdev->integrity_w_tfm) ?
    + crypto_hash_digestsize(mdev->integrity_w_tfm) : 0;
    +
    + p.head.magic = BE_DRBD_MAGIC;
    + p.head.command = cpu_to_be16(cmd);
    + p.head.length =
    + cpu_to_be16(sizeof(p) - sizeof(struct p_header) + dgs + e->size);
    +
    + p.sector = cpu_to_be64(e->sector);
    + p.block_id = e->block_id;
    + /* p.seq_num = 0; No sequence numbers here.. */
    +
    + /* Only called by our kernel thread.
    + * This one may be interupted by DRBD_SIG and/or DRBD_SIGKILL
    + * in response to admin command or module unload.
    + */
    + if (!drbd_get_data_sock(mdev))
    + return 0;
    +
    + trace_drbd_packet(mdev, mdev->data.socket, 0, (void *)&p, __FILE__, __LINE__);
    + ok = sizeof(p) == drbd_send(mdev, mdev->data.socket, &p,
    + sizeof(p), MSG_MORE);
    + if (ok && dgs) {
    + dgb = mdev->int_dig_out;
    + drbd_csum(mdev, mdev->integrity_w_tfm, e->private_bio, dgb);
    + ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
    + }
    + if (ok)
    + ok = _drbd_send_zc_bio(mdev, e->private_bio);
    +
    + drbd_put_data_sock(mdev);
    + return ok;
    +}
    +
    +/*
    + drbd_send distinguishes two cases:
    +
    + Packets sent via the data socket "sock"
    + and packets sent via the meta data socket "msock"
    +
    + sock msock
    + -----------------+-------------------------+------------------------------
    + timeout conf.timeout / 2 conf.timeout / 2
    + timeout action send a ping via msock Abort communication
    + and close all sockets
    +*/
    +
    +/*
    + * you must have down()ed the appropriate [m]sock_mutex elsewhere!
    + */
    +int drbd_send(struct drbd_conf *mdev, struct socket *sock,
    + void *buf, size_t size, unsigned msg_flags)
    +{
    + struct kvec iov;
    + struct msghdr msg;
    + int rv, sent = 0;
    +
    + if (!sock)
    + return -1000;
    +
    + /* THINK if (signal_pending) return ... ? */
    +
    + iov.iov_base = buf;
    + iov.iov_len = size;
    +
    + msg.msg_name = NULL;
    + msg.msg_namelen = 0;
    + msg.msg_control = NULL;
    + msg.msg_controllen = 0;
    + msg.msg_flags = msg_flags | MSG_NOSIGNAL;
    +
    + if (sock == mdev->data.socket) {
    + mdev->ko_count = mdev->net_conf->ko_count;
    + drbd_update_congested(mdev);
    + }
    + do {
    + /* STRANGE
    + * tcp_sendmsg does _not_ use its size parameter at all ?
    + *
    + * -EAGAIN on timeout, -EINTR on signal.
    + */
    +/* THINK
    + * do we need to block DRBD_SIG if sock == &meta.socket ??
    + * otherwise wake_asender() might interrupt some send_*Ack !
    + */
    + rv = kernel_sendmsg(sock, &msg, &iov, 1, size);
    + if (rv == -EAGAIN) {
    + if (we_should_drop_the_connection(mdev, sock))
    + break;
    + else
    + continue;
    + }
    + D_ASSERT(rv != 0);
    + if (rv == -EINTR) {
    + flush_signals(current);
    + rv = 0;
    + }
    + if (rv < 0)
    + break;
    + sent += rv;
    + iov.iov_base += rv;
    + iov.iov_len -= rv;
    + } while (sent < size);
    +
    + if (sock == mdev->data.socket)
    + clear_bit(NET_CONGESTED, &mdev->flags);
    +
    + if (rv <= 0) {
    + if (rv != -EAGAIN) {
    + dev_err(DEV, "%s_sendmsg returned %d\n",
    + sock == mdev->meta.socket ? "msock" : "sock",
    + rv);
    + drbd_force_state(mdev, NS(conn, C_BROKEN_PIPE));
    + } else
    + drbd_force_state(mdev, NS(conn, C_TIMEOUT));
    + }
    +
    + return sent;
    +}
    +
    +static int drbd_open(struct block_device *bdev, fmode_t mode)
    +{
    + struct drbd_conf *mdev = bdev->bd_disk->private_data;
    + unsigned long flags;
    + int rv = 0;
    +
    + spin_lock_irqsave(&mdev->req_lock, flags);
    + /* to have a stable mdev->state.role
    + * and no race with updating open_cnt */
    +
    + if (mdev->state.role != R_PRIMARY) {
    + if (mode & FMODE_WRITE)
    + rv = -EROFS;
    + else if (!allow_oos)
    + rv = -EMEDIUMTYPE;
    + }
    +
    + if (!rv)
    + mdev->open_cnt++;
    + spin_unlock_irqrestore(&mdev->req_lock, flags);
    +
    + return rv;
    +}
    +
    +static int drbd_release(struct gendisk *gd, fmode_t mode)
    +{
    + struct drbd_conf *mdev = gd->private_data;
    + mdev->open_cnt--;
    + return 0;
    +}
    +
    +STATIC void drbd_unplug_fn(struct request_queue *q)
    +{
    + struct drbd_conf *mdev = q->queuedata;
    +
    + trace_drbd_unplug(mdev, "got unplugged");
    +
    + /* unplug FIRST */
    + spin_lock_irq(q->queue_lock);
    + blk_remove_plug(q);
    + spin_unlock_irq(q->queue_lock);
    +
    + /* only if connected */
    + spin_lock_irq(&mdev->req_lock);
    + if (mdev->state.pdsk >= D_INCONSISTENT && mdev->state.conn >= C_CONNECTED) {
    + D_ASSERT(mdev->state.role == R_PRIMARY);
    + if (test_and_clear_bit(UNPLUG_REMOTE, &mdev->flags)) {
    + /* add to the data.work queue,
    + * unless already queued.
    + * XXX this might be a good addition to drbd_queue_work
    + * anyways, to detect "double queuing" ... */
    + if (list_empty(&mdev->unplug_work.list))
    + drbd_queue_work(&mdev->data.work,
    + &mdev->unplug_work);
    + }
    + }
    + spin_unlock_irq(&mdev->req_lock);
    +
    + if (mdev->state.disk >= D_INCONSISTENT)
    + drbd_kick_lo(mdev);
    +}
    +
    +STATIC void drbd_set_defaults(struct drbd_conf *mdev)
    +{
    + mdev->sync_conf.after = DRBD_AFTER_DEF;
    + mdev->sync_conf.rate = DRBD_RATE_DEF;
    + mdev->sync_conf.al_extents = DRBD_AL_EXTENTS_DEF;
    + mdev->state = (union drbd_state) {
    + { .role = R_SECONDARY,
    + .peer = R_UNKNOWN,
    + .conn = C_STANDALONE,
    + .disk = D_DISKLESS,
    + .pdsk = D_UNKNOWN,
    + .susp = 0
    + } };
    +}
    +
    +void drbd_init_set_defaults(struct drbd_conf *mdev)
    +{
    + /* the memset(,0,) did most of this.
    + * note: only assignments, no allocation in here */
    +
    + drbd_set_defaults(mdev);
    +
    + /* for now, we do NOT yet support it,
    + * even though we start some framework
    + * to eventually support barriers */
    + set_bit(NO_BARRIER_SUPP, &mdev->flags);
    +
    + atomic_set(&mdev->ap_bio_cnt, 0);
    + atomic_set(&mdev->ap_pending_cnt, 0);
    + atomic_set(&mdev->rs_pending_cnt, 0);
    + atomic_set(&mdev->unacked_cnt, 0);
    + atomic_set(&mdev->local_cnt, 0);
    + atomic_set(&mdev->net_cnt, 0);
    + atomic_set(&mdev->packet_seq, 0);
    + atomic_set(&mdev->pp_in_use, 0);
    +
    + mutex_init(&mdev->md_io_mutex);
    + mutex_init(&mdev->data.mutex);
    + mutex_init(&mdev->meta.mutex);
    + sema_init(&mdev->data.work.s, 0);
    + sema_init(&mdev->meta.work.s, 0);
    + mutex_init(&mdev->state_mutex);
    +
    + spin_lock_init(&mdev->data.work.q_lock);
    + spin_lock_init(&mdev->meta.work.q_lock);
    +
    + spin_lock_init(&mdev->al_lock);
    + spin_lock_init(&mdev->req_lock);
    + spin_lock_init(&mdev->peer_seq_lock);
    + spin_lock_init(&mdev->epoch_lock);
    +
    + INIT_LIST_HEAD(&mdev->active_ee);
    + INIT_LIST_HEAD(&mdev->sync_ee);
    + INIT_LIST_HEAD(&mdev->done_ee);
    + INIT_LIST_HEAD(&mdev->read_ee);
    + INIT_LIST_HEAD(&mdev->net_ee);
    + INIT_LIST_HEAD(&mdev->resync_reads);
    + INIT_LIST_HEAD(&mdev->data.work.q);
    + INIT_LIST_HEAD(&mdev->meta.work.q);
    + INIT_LIST_HEAD(&mdev->resync_work.list);
    + INIT_LIST_HEAD(&mdev->unplug_work.list);
    + INIT_LIST_HEAD(&mdev->md_sync_work.list);
    + INIT_LIST_HEAD(&mdev->bm_io_work.w.list);
    + mdev->resync_work.cb = w_resync_inactive;
    + mdev->unplug_work.cb = w_send_write_hint;
    + mdev->md_sync_work.cb = w_md_sync;
    + mdev->bm_io_work.w.cb = w_bitmap_io;
    + init_timer(&mdev->resync_timer);
    + init_timer(&mdev->md_sync_timer);
    + mdev->resync_timer.function = resync_timer_fn;
    + mdev->resync_timer.data = (unsigned long) mdev;
    + mdev->md_sync_timer.function = md_sync_timer_fn;
    + mdev->md_sync_timer.data = (unsigned long) mdev;
    +
    + init_waitqueue_head(&mdev->misc_wait);
    + init_waitqueue_head(&mdev->state_wait);
    + init_waitqueue_head(&mdev->ee_wait);
    + init_waitqueue_head(&mdev->al_wait);
    + init_waitqueue_head(&mdev->seq_wait);
    +
    + drbd_thread_init(mdev, &mdev->receiver, drbdd_init);
    + drbd_thread_init(mdev, &mdev->worker, drbd_worker);
    + drbd_thread_init(mdev, &mdev->asender, drbd_asender);
    +
    + mdev->agreed_pro_version = PRO_VERSION_MAX;
    + mdev->write_ordering = WO_bio_barrier;
    + mdev->resync_wenr = LC_FREE;
    +}
    +
    +void drbd_mdev_cleanup(struct drbd_conf *mdev)
    +{
    + if (mdev->receiver.t_state != None)
    + dev_err(DEV, "ASSERT FAILED: receiver t_state == %d expected 0.\n",
    + mdev->receiver.t_state);
    +
    + /* no need to lock it, I'm the only thread alive */
    + if (atomic_read(&mdev->current_epoch->epoch_size) != 0)
    + dev_err(DEV, "epoch_size:%d\n", atomic_read(&mdev->current_epoch->epoch_size));
    + mdev->al_writ_cnt =
    + mdev->bm_writ_cnt =
    + mdev->read_cnt =
    + mdev->recv_cnt =
    + mdev->send_cnt =
    + mdev->writ_cnt =
    + mdev->p_size =
    + mdev->rs_start =
    + mdev->rs_total =
    + mdev->rs_failed =
    + mdev->rs_mark_left =
    + mdev->rs_mark_time = 0;
    + D_ASSERT(mdev->net_conf == NULL);
    +
    + drbd_set_my_capacity(mdev, 0);
    + if (mdev->bitmap) {
    + /* maybe never allocated. */
    + drbd_bm_resize(mdev, 0);
    + drbd_bm_cleanup(mdev);
    + }
    +
    + drbd_free_resources(mdev);
    +
    + /*
    + * currently we drbd_init_ee only on module load, so
    + * we may do drbd_release_ee only on module unload!
    + */
    + D_ASSERT(list_empty(&mdev->active_ee));
    + D_ASSERT(list_empty(&mdev->sync_ee));
    + D_ASSERT(list_empty(&mdev->done_ee));
    + D_ASSERT(list_empty(&mdev->read_ee));
    + D_ASSERT(list_empty(&mdev->net_ee));
    + D_ASSERT(list_empty(&mdev->resync_reads));
    + D_ASSERT(list_empty(&mdev->data.work.q));
    + D_ASSERT(list_empty(&mdev->meta.work.q));
    + D_ASSERT(list_empty(&mdev->resync_work.list));
    + D_ASSERT(list_empty(&mdev->unplug_work.list));
    +
    +}
    +
    +
    +STATIC void drbd_destroy_mempools(void)
    +{
    + struct page *page;
    +
    + while (drbd_pp_pool) {
    + page = drbd_pp_pool;
    + drbd_pp_pool = (struct page *)page_private(page);
    + __free_page(page);
    + drbd_pp_vacant--;
    + }
    +
    + /* D_ASSERT(atomic_read(&drbd_pp_vacant)==0); */
    +
    + if (drbd_ee_mempool)
    + mempool_destroy(drbd_ee_mempool);
    + if (drbd_request_mempool)
    + mempool_destroy(drbd_request_mempool);
    + if (drbd_ee_cache)
    + kmem_cache_destroy(drbd_ee_cache);
    + if (drbd_request_cache)
    + kmem_cache_destroy(drbd_request_cache);
    +
    + drbd_ee_mempool = NULL;
    + drbd_request_mempool = NULL;
    + drbd_ee_cache = NULL;
    + drbd_request_cache = NULL;
    +
    + return;
    +}
    +
    +STATIC int drbd_create_mempools(void)
    +{
    + struct page *page;
    + const int number = (DRBD_MAX_SEGMENT_SIZE/PAGE_SIZE) * minor_count;
    + int i;
    +
    + /* prepare our caches and mempools */
    + drbd_request_mempool = NULL;
    + drbd_ee_cache = NULL;
    + drbd_request_cache = NULL;
    + drbd_pp_pool = NULL;
    +
    + /* caches */
    + drbd_request_cache = kmem_cache_create(
    + "drbd_req_cache", sizeof(struct drbd_request), 0, 0, NULL);
    + if (drbd_request_cache == NULL)
    + goto Enomem;
    +
    + drbd_ee_cache = kmem_cache_create(
    + "drbd_ee_cache", sizeof(struct drbd_epoch_entry), 0, 0, NULL);
    + if (drbd_ee_cache == NULL)
    + goto Enomem;
    +
    + /* mempools */
    + drbd_request_mempool = mempool_create(number,
    + mempool_alloc_slab, mempool_free_slab, drbd_request_cache);
    + if (drbd_request_mempool == NULL)
    + goto Enomem;
    +
    + drbd_ee_mempool = mempool_create(number,
    + mempool_alloc_slab, mempool_free_slab, drbd_ee_cache);
    + if (drbd_request_mempool == NULL)
    + goto Enomem;
    +
    + /* drbd's page pool */
    + spin_lock_init(&drbd_pp_lock);
    +
    + for (i = 0; i < number; i++) {
    + page = alloc_page(GFP_HIGHUSER);
    + if (!page)
    + goto Enomem;
    + set_page_private(page, (unsigned long)drbd_pp_pool);
    + drbd_pp_pool = page;
    + }
    + drbd_pp_vacant = number;
    +
    + return 0;
    +
    +Enomem:
    + drbd_destroy_mempools(); /* in case we allocated some */
    + return -ENOMEM;
    +}
    +
    +STATIC int drbd_notify_sys(struct notifier_block *this, unsigned long code,
    + void *unused)
    +{
    + /* just so we have it. you never know what interessting things we
    + * might want to do here some day...
    + */
    +
    + return NOTIFY_DONE;
    +}
    +
    +STATIC struct notifier_block drbd_notifier = {
    + .notifier_call = drbd_notify_sys,
    +};
    +
    +static void drbd_release_ee_lists(struct drbd_conf *mdev)
    +{
    + int rr;
    +
    + rr = drbd_release_ee(mdev, &mdev->active_ee);
    + if (rr)
    + dev_err(DEV, "%d EEs in active list found!\n", rr);
    +
    + rr = drbd_release_ee(mdev, &mdev->sync_ee);
    + if (rr)
    + dev_err(DEV, "%d EEs in sync list found!\n", rr);
    +
    + rr = drbd_release_ee(mdev, &mdev->read_ee);
    + if (rr)
    + dev_err(DEV, "%d EEs in read list found!\n", rr);
    +
    + rr = drbd_release_ee(mdev, &mdev->done_ee);
    + if (rr)
    + dev_err(DEV, "%d EEs in done list found!\n", rr);
    +
    + rr = drbd_release_ee(mdev, &mdev->net_ee);
    + if (rr)
    + dev_err(DEV, "%d EEs in net list found!\n", rr);
    +}
    +
    +/* caution. no locking.
    + * currently only used from module cleanup code. */
    +static void drbd_delete_device(unsigned int minor)
    +{
    + struct drbd_conf *mdev = minor_to_mdev(minor);
    +
    + if (!mdev)
    + return;
    +
    + /* paranoia asserts */
    + if (mdev->open_cnt != 0)
    + dev_err(DEV, "open_cnt = %d in %s:%u", mdev->open_cnt,
    + __FILE__ , __LINE__);
    +
    + ERR_IF (!list_empty(&mdev->data.work.q)) {
    + struct list_head *lp;
    + list_for_each(lp, &mdev->data.work.q) {
    + DUMPP(lp);
    + }
    + };
    + /* end paranoia asserts */
    +
    + del_gendisk(mdev->vdisk);
    +
    + /* cleanup stuff that may have been allocated during
    + * device (re-)configuration or state changes */
    +
    + if (mdev->this_bdev)
    + bdput(mdev->this_bdev);
    +
    + drbd_free_resources(mdev);
    +
    + drbd_release_ee_lists(mdev);
    +
    + /* should be free'd on disconnect? */
    + kfree(mdev->ee_hash);
    + /*
    + mdev->ee_hash_s = 0;
    + mdev->ee_hash = NULL;
    + */
    +
    + lc_destroy(mdev->act_log);
    + lc_destroy(mdev->resync);
    +
    + kfree(mdev->p_uuid);
    + /* mdev->p_uuid = NULL; */
    +
    + kfree(mdev->int_dig_out);
    + kfree(mdev->int_dig_in);
    + kfree(mdev->int_dig_vv);
    +
    + /* cleanup the rest that has been
    + * allocated from drbd_new_device
    + * and actually free the mdev itself */
    + drbd_free_mdev(mdev);
    +}
    +
    +STATIC void drbd_cleanup(void)
    +{
    + unsigned int i;
    +
    + unregister_reboot_notifier(&drbd_notifier);
    +
    + drbd_nl_cleanup();
    +
    + if (minor_table) {
    + if (drbd_proc)
    + remove_proc_entry("drbd", NULL);
    + i = minor_count;
    + while (i--)
    + drbd_delete_device(i);
    + drbd_destroy_mempools();
    + }
    +
    + kfree(minor_table);
    +
    + unregister_blkdev(DRBD_MAJOR, "drbd");
    +
    + printk(KERN_INFO "drbd: module cleanup done.\n");
    +}
    +
    +/**
    + * drbd_congested() - Callback for pdflush
    + * @congested_data: User data
    + * @bdi_bits: Bits pdflush is currently interested in
    + *
    + * Returns 1<<BDI_async_congested and/or 1<<BDI_sync_congested if we are congested.
    + */
    +static int drbd_congested(void *congested_data, int bdi_bits)
    +{
    + struct drbd_conf *mdev = congested_data;
    + struct request_queue *q;
    + char reason = '-';
    + int r = 0;
    +
    + if (!__inc_ap_bio_cond(mdev)) {
    + /* DRBD has frozen IO */
    + r = bdi_bits;
    + reason = 'd';
    + goto out;
    + }
    +
    + if (get_ldev(mdev)) {
    + q = bdev_get_queue(mdev->ldev->backing_bdev);
    + r = bdi_congested(&q->backing_dev_info, bdi_bits);
    + put_ldev(mdev);
    + if (r)
    + reason = 'b';
    + }
    +
    + if (bdi_bits & (1 << BDI_async_congested) && test_bit(NET_CONGESTED, &mdev->flags)) {
    + r |= (1 << BDI_async_congested);
    + reason = reason == 'b' ? 'a' : 'n';
    + }
    +
    +out:
    + mdev->congestion_reason = reason;
    + return r;
    +}
    +
    +struct drbd_conf *drbd_new_device(unsigned int minor)
    +{
    + struct drbd_conf *mdev;
    + struct gendisk *disk;
    + struct request_queue *q;
    +
    + mdev = kzalloc(sizeof(struct drbd_conf), GFP_KERNEL);
    + if (!mdev)
    + return NULL;
    +
    + mdev->minor = minor;
    +
    + drbd_init_set_defaults(mdev);
    +
    + q = blk_alloc_queue(GFP_KERNEL);
    + if (!q)
    + goto out_no_q;
    + mdev->rq_queue = q;
    + q->queuedata = mdev;
    + q->max_segment_size = DRBD_MAX_SEGMENT_SIZE;
    +
    + disk = alloc_disk(1);
    + if (!disk)
    + goto out_no_disk;
    + mdev->vdisk = disk;
    +
    + set_disk_ro(disk, TRUE);
    +
    + disk->queue = q;
    + disk->major = DRBD_MAJOR;
    + disk->first_minor = minor;
    + disk->fops = &drbd_ops;
    + sprintf(disk->disk_name, "drbd%d", minor);
    + disk->private_data = mdev;
    +
    + mdev->this_bdev = bdget(MKDEV(DRBD_MAJOR, minor));
    + /* we have no partitions. we contain only ourselves. */
    + mdev->this_bdev->bd_contains = mdev->this_bdev;
    +
    + q->backing_dev_info.congested_fn = drbd_congested;
    + q->backing_dev_info.congested_data = mdev;
    +
    + blk_queue_make_request(q, drbd_make_request_26);
    + blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
    + blk_queue_merge_bvec(q, drbd_merge_bvec);
    + q->queue_lock = &mdev->req_lock; /* needed since we use */
    + /* plugging on a queue, that actually has no requests! */
    + q->unplug_fn = drbd_unplug_fn;
    +
    + mdev->md_io_page = alloc_page(GFP_KERNEL);
    + if (!mdev->md_io_page)
    + goto out_no_io_page;
    +
    + if (drbd_bm_init(mdev))
    + goto out_no_bitmap;
    + /* no need to lock access, we are still initializing the module. */
    + if (!tl_init(mdev))
    + goto out_no_tl;
    +
    + mdev->app_reads_hash = kzalloc(APP_R_HSIZE*sizeof(void *), GFP_KERNEL);
    + if (!mdev->app_reads_hash)
    + goto out_no_app_reads;
    +
    + mdev->current_epoch = kzalloc(sizeof(struct drbd_epoch), GFP_KERNEL);
    + if (!mdev->current_epoch)
    + goto out_no_epoch;
    +
    + INIT_LIST_HEAD(&mdev->current_epoch->list);
    + mdev->epochs = 1;
    +
    + return mdev;
    +
    +/* out_whatever_else:
    + kfree(mdev->current_epoch); */
    +out_no_epoch:
    + kfree(mdev->app_reads_hash);
    +out_no_app_reads:
    + tl_cleanup(mdev);
    +out_no_tl:
    + drbd_bm_cleanup(mdev);
    +out_no_bitmap:
    + __free_page(mdev->md_io_page);
    +out_no_io_page:
    + put_disk(disk);
    +out_no_disk:
    + blk_cleanup_queue(q);
    +out_no_q:
    + kfree(mdev);
    + return NULL;
    +}
    +
    +/* counterpart of drbd_new_device.
    + * last part of drbd_delete_device. */
    +void drbd_free_mdev(struct drbd_conf *mdev)
    +{
    + kfree(mdev->current_epoch);
    + kfree(mdev->app_reads_hash);
    + tl_cleanup(mdev);
    + if (mdev->bitmap) /* should no longer be there. */
    + drbd_bm_cleanup(mdev);
    + __free_page(mdev->md_io_page);
    + put_disk(mdev->vdisk);
    + blk_cleanup_queue(mdev->rq_queue);
    + kfree(mdev);
    +}
    +
    +
    +int __init drbd_init(void)
    +{
    + int err;
    +
    + if (sizeof(struct p_handshake) != 80) {
    + printk(KERN_ERR
    + "drbd: never change the size or layout "
    + "of the HandShake packet.\n");
    + return -EINVAL;
    + }
    +
    + if (1 > minor_count || minor_count > 255) {
    + printk(KERN_ERR
    + "drbd: invalid minor_count (%d)\n", minor_count);
    +#ifdef MODULE
    + return -EINVAL;
    +#else
    + minor_count = 8;
    +#endif
    + }
    +
    + err = drbd_nl_init();
    + if (err)
    + return err;
    +
    + err = register_blkdev(DRBD_MAJOR, "drbd");
    + if (err) {
    + printk(KERN_ERR
    + "drbd: unable to register block device major %d\n",
    + DRBD_MAJOR);
    + return err;
    + }
    +
    + register_reboot_notifier(&drbd_notifier);
    +
    + /*
    + * allocate all necessary structs
    + */
    + err = -ENOMEM;
    +
    + init_waitqueue_head(&drbd_pp_wait);
    +
    + drbd_proc = NULL; /* play safe for drbd_cleanup */
    + minor_table = kzalloc(sizeof(struct drbd_conf *)*minor_count,
    + GFP_KERNEL);
    + if (!minor_table)
    + goto Enomem;
    +
    + err = drbd_create_mempools();
    + if (err)
    + goto Enomem;
    +
    + drbd_proc = proc_create("drbd", S_IFREG | S_IRUGO , NULL, &drbd_proc_fops);
    + if (!drbd_proc) {
    + printk(KERN_ERR "drbd: unable to register proc file\n");
    + goto Enomem;
    + }
    +
    + rwlock_init(&global_state_lock);
    +
    + printk(KERN_INFO "drbd: initialised. "
    + "Version: " REL_VERSION " (api:%d/proto:%d-%d)\n",
    + API_VERSION, PRO_VERSION_MIN, PRO_VERSION_MAX);
    + printk(KERN_INFO "drbd: %s\n", drbd_buildtag());
    + printk(KERN_INFO "drbd: registered as block device major %d\n",
    + DRBD_MAJOR);
    + printk(KERN_INFO "drbd: minor_table @ 0x%p\n", minor_table);
    +
    + return 0; /* Success! */
    +
    +Enomem:
    + drbd_cleanup();
    + if (err == -ENOMEM)
    + /* currently always the case */
    + printk(KERN_ERR "drbd: ran out of memory\n");
    + else
    + printk(KERN_ERR "drbd: initialization failure\n");
    + return err;
    +}
    +
    +void drbd_free_bc(struct drbd_backing_dev *ldev)
    +{
    + if (ldev == NULL)
    + return;
    +
    + bd_release(ldev->backing_bdev);
    + bd_release(ldev->md_bdev);
    +
    + fput(ldev->lo_file);
    + fput(ldev->md_file);
    +
    + kfree(ldev);
    +}
    +
    +void drbd_free_sock(struct drbd_conf *mdev)
    +{
    + if (mdev->data.socket) {
    + sock_release(mdev->data.socket);
    + mdev->data.socket = NULL;
    + }
    + if (mdev->meta.socket) {
    + sock_release(mdev->meta.socket);
    + mdev->meta.socket = NULL;
    + }
    +}
    +
    +
    +void drbd_free_resources(struct drbd_conf *mdev)
    +{
    + crypto_free_hash(mdev->csums_tfm);
    + mdev->csums_tfm = NULL;
    + crypto_free_hash(mdev->verify_tfm);
    + mdev->verify_tfm = NULL;
    + crypto_free_hash(mdev->cram_hmac_tfm);
    + mdev->cram_hmac_tfm = NULL;
    + crypto_free_hash(mdev->integrity_w_tfm);
    + mdev->integrity_w_tfm = NULL;
    + crypto_free_hash(mdev->integrity_r_tfm);
    + mdev->integrity_r_tfm = NULL;
    +
    + drbd_free_sock(mdev);
    +
    + __no_warn(local,
    + drbd_free_bc(mdev->ldev);
    + mdev->ldev = NULL;);
    +}
    +
    +/* meta data management */
    +
    +struct meta_data_on_disk {
    + u64 la_size; /* last agreed size. */
    + u64 uuid[UI_SIZE]; /* UUIDs. */
    + u64 device_uuid;
    + u64 reserved_u64_1;
    + u32 flags; /* MDF */
    + u32 magic;
    + u32 md_size_sect;
    + u32 al_offset; /* offset to this block */
    + u32 al_nr_extents; /* important for restoring the AL */
    + /* `-- act_log->nr_elements <-- sync_conf.al_extents */
    + u32 bm_offset; /* offset to the bitmap, from here */
    + u32 bm_bytes_per_bit; /* BM_BLOCK_SIZE */
    + u32 reserved_u32[4];
    +
    +} __packed;
    +
    +/**
    + * drbd_md_sync() - Writes the meta data super block if the MD_DIRTY flag bit is set
    + * @mdev: DRBD device.
    + */
    +void drbd_md_sync(struct drbd_conf *mdev)
    +{
    + struct meta_data_on_disk *buffer;
    + sector_t sector;
    + int i;
    +
    + if (!test_and_clear_bit(MD_DIRTY, &mdev->flags))
    + return;
    + del_timer(&mdev->md_sync_timer);
    +
    + /* We use here D_FAILED and not D_ATTACHING because we try to write
    + * metadata even if we detach due to a disk failure! */
    + if (!get_ldev_if_state(mdev, D_FAILED))
    + return;
    +
    + trace_drbd_md_io(mdev, WRITE, mdev->ldev);
    +
    + mutex_lock(&mdev->md_io_mutex);
    + buffer = (struct meta_data_on_disk *)page_address(mdev->md_io_page);
    + memset(buffer, 0, 512);
    +
    + buffer->la_size = cpu_to_be64(drbd_get_capacity(mdev->this_bdev));
    + for (i = UI_CURRENT; i < UI_SIZE; i++)
    + buffer->uuid[i] = cpu_to_be64(mdev->ldev->md.uuid[i]);
    + buffer->flags = cpu_to_be32(mdev->ldev->md.flags);
    + buffer->magic = cpu_to_be32(DRBD_MD_MAGIC);
    +
    + buffer->md_size_sect = cpu_to_be32(mdev->ldev->md.md_size_sect);
    + buffer->al_offset = cpu_to_be32(mdev->ldev->md.al_offset);
    + buffer->al_nr_extents = cpu_to_be32(mdev->act_log->nr_elements);
    + buffer->bm_bytes_per_bit = cpu_to_be32(BM_BLOCK_SIZE);
    + buffer->device_uuid = cpu_to_be64(mdev->ldev->md.device_uuid);
    +
    + buffer->bm_offset = cpu_to_be32(mdev->ldev->md.bm_offset);
    +
    + D_ASSERT(drbd_md_ss__(mdev, mdev->ldev) == mdev->ldev->md.md_offset);
    + sector = mdev->ldev->md.md_offset;
    +
    + if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
    + clear_bit(MD_DIRTY, &mdev->flags);
    + } else {
    + /* this was a try anyways ... */
    + dev_err(DEV, "meta data update failed!\n");
    +
    + drbd_chk_io_error(mdev, 1, TRUE);
    + drbd_io_error(mdev, TRUE);
    + }
    +
    + /* Update mdev->ldev->md.la_size_sect,
    + * since we updated it on metadata. */
    + mdev->ldev->md.la_size_sect = drbd_get_capacity(mdev->this_bdev);
    +
    + mutex_unlock(&mdev->md_io_mutex);
    + put_ldev(mdev);
    +}
    +
    +/**
    + * drbd_md_read() - Reads in the meta data super block
    + * @mdev: DRBD device.
    + * @bdev: Device from which the meta data should be read in.
    + *
    + * Return 0 (NO_ERROR) on success, and an enum drbd_ret_codes in case
    + * something goes wrong. Currently only: ERR_IO_MD_DISK, ERR_MD_INVALID.
    + */
    +int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
    +{
    + struct meta_data_on_disk *buffer;
    + int i, rv = NO_ERROR;
    +
    + if (!get_ldev_if_state(mdev, D_ATTACHING))
    + return ERR_IO_MD_DISK;
    +
    + trace_drbd_md_io(mdev, READ, bdev);
    +
    + mutex_lock(&mdev->md_io_mutex);
    + buffer = (struct meta_data_on_disk *)page_address(mdev->md_io_page);
    +
    + if (!drbd_md_sync_page_io(mdev, bdev, bdev->md.md_offset, READ)) {
    + /* NOTE: cant do normal error processing here as this is
    + called BEFORE disk is attached */
    + dev_err(DEV, "Error while reading metadata.\n");
    + rv = ERR_IO_MD_DISK;
    + goto err;
    + }
    +
    + if (be32_to_cpu(buffer->magic) != DRBD_MD_MAGIC) {
    + dev_err(DEV, "Error while reading metadata, magic not found.\n");
    + rv = ERR_MD_INVALID;
    + goto err;
    + }
    + if (be32_to_cpu(buffer->al_offset) != bdev->md.al_offset) {
    + dev_err(DEV, "unexpected al_offset: %d (expected %d)\n",
    + be32_to_cpu(buffer->al_offset), bdev->md.al_offset);
    + rv = ERR_MD_INVALID;
    + goto err;
    + }
    + if (be32_to_cpu(buffer->bm_offset) != bdev->md.bm_offset) {
    + dev_err(DEV, "unexpected bm_offset: %d (expected %d)\n",
    + be32_to_cpu(buffer->bm_offset), bdev->md.bm_offset);
    + rv = ERR_MD_INVALID;
    + goto err;
    + }
    + if (be32_to_cpu(buffer->md_size_sect) != bdev->md.md_size_sect) {
    + dev_err(DEV, "unexpected md_size: %u (expected %u)\n",
    + be32_to_cpu(buffer->md_size_sect), bdev->md.md_size_sect);
    + rv = ERR_MD_INVALID;
    + goto err;
    + }
    +
    + if (be32_to_cpu(buffer->bm_bytes_per_bit) != BM_BLOCK_SIZE) {
    + dev_err(DEV, "unexpected bm_bytes_per_bit: %u (expected %u)\n",
    + be32_to_cpu(buffer->bm_bytes_per_bit), BM_BLOCK_SIZE);
    + rv = ERR_MD_INVALID;
    + goto err;
    + }
    +
    + bdev->md.la_size_sect = be64_to_cpu(buffer->la_size);
    + for (i = UI_CURRENT; i < UI_SIZE; i++)
    + bdev->md.uuid[i] = be64_to_cpu(buffer->uuid[i]);
    + bdev->md.flags = be32_to_cpu(buffer->flags);
    + mdev->sync_conf.al_extents = be32_to_cpu(buffer->al_nr_extents);
    + bdev->md.device_uuid = be64_to_cpu(buffer->device_uuid);
    +
    + if (mdev->sync_conf.al_extents < 7)
    + mdev->sync_conf.al_extents = 127;
    +
    + err:
    + mutex_unlock(&mdev->md_io_mutex);
    + put_ldev(mdev);
    +
    + return rv;
    +}
    +
    +/**
    + * drbd_md_mark_dirty() - Mark meta data super block as dirty
    + * @mdev: DRBD device.
    + *
    + * Call this function if you change enything that should be written to
    + * the meta-data super block. This function sets MD_DIRTY, and starts a
    + * timer that ensures that within five seconds you have to call drbd_md_sync().
    + */
    +void drbd_md_mark_dirty(struct drbd_conf *mdev)
    +{
    + set_bit(MD_DIRTY, &mdev->flags);
    + mod_timer(&mdev->md_sync_timer, jiffies + 5*HZ);
    +}
    +
    +
    +STATIC void drbd_uuid_move_history(struct drbd_conf *mdev) __must_hold(local)
    +{
    + int i;
    +
    + for (i = UI_HISTORY_START; i < UI_HISTORY_END; i++) {
    + mdev->ldev->md.uuid[i+1] = mdev->ldev->md.uuid[i];
    +
    + trace_drbd_uuid(mdev, i+1);
    + }
    +}
    +
    +void _drbd_uuid_set(struct drbd_conf *mdev, int idx, u64 val) __must_hold(local)
    +{
    + if (idx == UI_CURRENT) {
    + if (mdev->state.role == R_PRIMARY)
    + val |= 1;
    + else
    + val &= ~((u64)1);
    +
    + drbd_set_ed_uuid(mdev, val);
    + }
    +
    + mdev->ldev->md.uuid[idx] = val;
    + trace_drbd_uuid(mdev, idx);
    + drbd_md_mark_dirty(mdev);
    +}
    +
    +
    +void drbd_uuid_set(struct drbd_conf *mdev, int idx, u64 val) __must_hold(local)
    +{
    + if (mdev->ldev->md.uuid[idx]) {
    + drbd_uuid_move_history(mdev);
    + mdev->ldev->md.uuid[UI_HISTORY_START] = mdev->ldev->md.uuid[idx];
    + trace_drbd_uuid(mdev, UI_HISTORY_START);
    + }
    + _drbd_uuid_set(mdev, idx, val);
    +}
    +
    +/**
    + * drbd_uuid_new_current() - Creates a new current UUID
    + * @mdev: DRBD device.
    + *
    + * Creates a new current UUID, and rotates the old current UUID into
    + * the bitmap slot. Causes an incremental resync upon next connect.
    + */
    +void drbd_uuid_new_current(struct drbd_conf *mdev) __must_hold(local)
    +{
    + u64 val;
    +
    + dev_info(DEV, "Creating new current UUID\n");
    + D_ASSERT(mdev->ldev->md.uuid[UI_BITMAP] == 0);
    + mdev->ldev->md.uuid[UI_BITMAP] = mdev->ldev->md.uuid[UI_CURRENT];
    + trace_drbd_uuid(mdev, UI_BITMAP);
    +
    + get_random_bytes(&val, sizeof(u64));
    + _drbd_uuid_set(mdev, UI_CURRENT, val);
    +}
    +
    +void drbd_uuid_set_bm(struct drbd_conf *mdev, u64 val) __must_hold(local)
    +{
    + if (mdev->ldev->md.uuid[UI_BITMAP] == 0 && val == 0)
    + return;
    +
    + if (val == 0) {
    + drbd_uuid_move_history(mdev);
    + mdev->ldev->md.uuid[UI_HISTORY_START] = mdev->ldev->md.uuid[UI_BITMAP];
    + mdev->ldev->md.uuid[UI_BITMAP] = 0;
    + trace_drbd_uuid(mdev, UI_HISTORY_START);
    + trace_drbd_uuid(mdev, UI_BITMAP);
    + } else {
    + if (mdev->ldev->md.uuid[UI_BITMAP])
    + dev_warn(DEV, "bm UUID already set");
    +
    + mdev->ldev->md.uuid[UI_BITMAP] = val;
    + mdev->ldev->md.uuid[UI_BITMAP] &= ~((u64)1);
    +
    + trace_drbd_uuid(mdev, UI_BITMAP);
    + }
    + drbd_md_mark_dirty(mdev);
    +}
    +
    +/**
    + * drbd_bmio_set_n_write() - io_fn for drbd_queue_bitmap_io() or drbd_bitmap_io()
    + * @mdev: DRBD device.
    + *
    + * Sets all bits in the bitmap and writes the whole bitmap to stable storage.
    + */
    +int drbd_bmio_set_n_write(struct drbd_conf *mdev)
    +{
    + int rv = -EIO;
    +
    + if (get_ldev_if_state(mdev, D_ATTACHING)) {
    + drbd_md_set_flag(mdev, MDF_FULL_SYNC);
    + drbd_md_sync(mdev);
    + drbd_bm_set_all(mdev);
    +
    + rv = drbd_bm_write(mdev);
    +
    + if (!rv) {
    + drbd_md_clear_flag(mdev, MDF_FULL_SYNC);
    + drbd_md_sync(mdev);
    + }
    +
    + put_ldev(mdev);
    + }
    +
    + return rv;
    +}
    +
    +/**
    + * drbd_bmio_clear_n_write() - io_fn for drbd_queue_bitmap_io() or drbd_bitmap_io()
    + * @mdev: DRBD device.
    + *
    + * Clears all bits in the bitmap and writes the whole bitmap to stable storage.
    + */
    +int drbd_bmio_clear_n_write(struct drbd_conf *mdev)
    +{
    + int rv = -EIO;
    +
    + if (get_ldev_if_state(mdev, D_ATTACHING)) {
    + drbd_bm_clear_all(mdev);
    + rv = drbd_bm_write(mdev);
    + put_ldev(mdev);
    + }
    +
    + return rv;
    +}
    +
    +STATIC int w_bitmap_io(struct drbd_conf *mdev, struct drbd_work *w, int unused)
    +{
    + struct bm_io_work *work = (struct bm_io_work *)w;
    + int rv;
    +
    + D_ASSERT(atomic_read(&mdev->ap_bio_cnt) == 0);
    +
    + drbd_bm_lock(mdev, work->why);
    + rv = work->io_fn(mdev);
    + drbd_bm_unlock(mdev);
    +
    + clear_bit(BITMAP_IO, &mdev->flags);
    + wake_up(&mdev->misc_wait);
    +
    + if (work->done)
    + work->done(mdev, rv);
    +
    + clear_bit(BITMAP_IO_QUEUED, &mdev->flags);
    + work->why = NULL;
    +
    + return 1;
    +}
    +
    +/**
    + * drbd_queue_bitmap_io() - Queues an IO operation on the whole bitmap
    + * @mdev: DRBD device.
    + * @io_fn: IO callback to be called when bitmap IO is possible
    + * @done: callback to be called after the bitmap IO was performed
    + * @why: Descriptive text of the reason for doing the IO
    + *
    + * While IO on the bitmap happens we freeze appliation IO thus we ensure
    + * that drbd_set_out_of_sync() can not be called. This function MAY ONLY be
    + * called from worker context. It MUST NOT be used while a previous such
    + * work is still pending!
    + */
    +void drbd_queue_bitmap_io(struct drbd_conf *mdev,
    + int (*io_fn)(struct drbd_conf *),
    + void (*done)(struct drbd_conf *, int),
    + char *why)
    +{
    + D_ASSERT(current == mdev->worker.task);
    +
    + D_ASSERT(!test_bit(BITMAP_IO_QUEUED, &mdev->flags));
    + D_ASSERT(!test_bit(BITMAP_IO, &mdev->flags));
    + D_ASSERT(list_empty(&mdev->bm_io_work.w.list));
    + if (mdev->bm_io_work.why)
    + dev_err(DEV, "FIXME going to queue '%s' but '%s' still pending?\n",
    + why, mdev->bm_io_work.why);
    +
    + mdev->bm_io_work.io_fn = io_fn;
    + mdev->bm_io_work.done = done;
    + mdev->bm_io_work.why = why;
    +
    + set_bit(BITMAP_IO, &mdev->flags);
    + if (atomic_read(&mdev->ap_bio_cnt) == 0) {
    + if (list_empty(&mdev->bm_io_work.w.list)) {
    + set_bit(BITMAP_IO_QUEUED, &mdev->flags);
    + drbd_queue_work(&mdev->data.work, &mdev->bm_io_work.w);
    + } else
    + dev_err(DEV, "FIXME avoided double queuing bm_io_work\n");
    + }
    +}
    +
    +/**
    + * drbd_bitmap_io() - Does an IO operation on the whole bitmap
    + * @mdev: DRBD device.
    + * @io_fn: IO callback to be called when bitmap IO is possible
    + * @why: Descriptive text of the reason for doing the IO
    + *
    + * freezes application IO while that the actual IO operations runs. This
    + * functions MAY NOT be called from worker context.
    + */
    +int drbd_bitmap_io(struct drbd_conf *mdev, int (*io_fn)(struct drbd_conf *), char *why)
    +{
    + int rv;
    +
    + D_ASSERT(current != mdev->worker.task);
    +
    + drbd_suspend_io(mdev);
    +
    + drbd_bm_lock(mdev, why);
    + rv = io_fn(mdev);
    + drbd_bm_unlock(mdev);
    +
    + drbd_resume_io(mdev);
    +
    + return rv;
    +}
    +
    +void drbd_md_set_flag(struct drbd_conf *mdev, int flag) __must_hold(local)
    +{
    + if ((mdev->ldev->md.flags & flag) != flag) {
    + drbd_md_mark_dirty(mdev);
    + mdev->ldev->md.flags |= flag;
    + }
    +}
    +
    +void drbd_md_clear_flag(struct drbd_conf *mdev, int flag) __must_hold(local)
    +{
    + if ((mdev->ldev->md.flags & flag) != 0) {
    + drbd_md_mark_dirty(mdev);
    + mdev->ldev->md.flags &= ~flag;
    + }
    +}
    +int drbd_md_test_flag(struct drbd_backing_dev *bdev, int flag)
    +{
    + return (bdev->md.flags & flag) != 0;
    +}
    +
    +STATIC void md_sync_timer_fn(unsigned long data)
    +{
    + struct drbd_conf *mdev = (struct drbd_conf *) data;
    +
    + drbd_queue_work_front(&mdev->data.work, &mdev->md_sync_work);
    +}
    +
    +STATIC int w_md_sync(struct drbd_conf *mdev, struct drbd_work *w, int unused)
    +{
    + dev_warn(DEV, "md_sync_timer expired! Worker calls drbd_md_sync().\n");
    + drbd_md_sync(mdev);
    +
    + return 1;
    +}
    +
    +#ifdef DRBD_ENABLE_FAULTS
    +/* Fault insertion support including random number generator shamelessly
    + * stolen from kernel/rcutorture.c */
    +struct fault_random_state {
    + unsigned long state;
    + unsigned long count;
    +};
    +
    +#define FAULT_RANDOM_MULT 39916801 /* prime */
    +#define FAULT_RANDOM_ADD 479001701 /* prime */
    +#define FAULT_RANDOM_REFRESH 10000
    +
    +/*
    + * Crude but fast random-number generator. Uses a linear congruential
    + * generator, with occasional help from get_random_bytes().
    + */
    +STATIC unsigned long
    +_drbd_fault_random(struct fault_random_state *rsp)
    +{
    + long refresh;
    +
    + if (--rsp->count < 0) {
    + get_random_bytes(&refresh, sizeof(refresh));
    + rsp->state += refresh;
    + rsp->count = FAULT_RANDOM_REFRESH;
    + }
    + rsp->state = rsp->state * FAULT_RANDOM_MULT + FAULT_RANDOM_ADD;
    + return swahw32(rsp->state);
    +}
    +
    +STATIC char *
    +_drbd_fault_str(unsigned int type) {
    + static char *_faults[] = {
    + "Meta-data write",
    + "Meta-data read",
    + "Resync write",
    + "Resync read",
    + "Data write",
    + "Data read",
    + "Data read ahead",
    + "BM allocation",
    + "EE allocation"
    + };
    +
    + return (type < DRBD_FAULT_MAX) ? _faults[type] : "**Unknown**";
    +}
    +
    +unsigned int
    +_drbd_insert_fault(struct drbd_conf *mdev, unsigned int type)
    +{
    + static struct fault_random_state rrs = {0, 0};
    +
    + unsigned int ret = (
    + (fault_devs == 0 ||
    + ((1 << mdev_to_minor(mdev)) & fault_devs) != 0) &&
    + (((_drbd_fault_random(&rrs) % 100) + 1) <= fault_rate));
    +
    + if (ret) {
    + fault_count++;
    +
    + if (printk_ratelimit())
    + dev_warn(DEV, "***Simulating %s failure\n",
    + _drbd_fault_str(type));
    + }
    +
    + return ret;
    +}
    +#endif
    +
    +module_init(drbd_init)
    +module_exit(drbd_cleanup)

    \
     
     \ /
      Last update: 2009-05-15 14:15    [W:0.220 / U:180.544 seconds]
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