[PATCH 10/13] DRBD: worker

Philipp Reisner
2009-03-30T16:50:31Z

Our generic worker thread. Does the actual sending of data via the network
link. Does all the after-state-change activities, that have to be done
without holding the req_lock spinlock. And some other stuff.

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

---
diff -uNrp linux-2.6.29/drivers/block/drbd/drbd_worker.c linux-2.6.29-drbd/drivers/block/drbd/drbd_worker.c
--- linux-2.6.29/drivers/block/drbd/drbd_worker.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.29-drbd/drivers/block/drbd/drbd_worker.c 2009-03-30 16:51:48.331706000 +0200
@@ -0,0 +1,1463 @@
+/*
+ drbd_worker.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 <linux/sched.h>
+#include <linux/smp_lock.h>
+#include <linux/wait.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/mm.h>
+#include <linux/string.h>
+#include <linux/scatterlist.h>
+
+#include <linux/drbd.h>
+#include "drbd_int.h"
+#include "drbd_req.h"
+
+#define SLEEP_TIME (HZ/10)
+
+STATIC int w_make_ov_request(struct drbd_conf *mdev, struct drbd_work *w, int cancel);
+
+
+
+/* defined here:
+ drbd_md_io_complete
+ drbd_endio_write_sec
+ drbd_endio_read_sec
+ drbd_endio_pri
+
+ * more endio handlers:
+ atodb_endio in drbd_actlog.c
+ drbd_bm_async_io_complete in drbd_bitmap.c
+
+ * For all these callbacks, note the follwing:
+ * The callbacks will be called in irq context by the IDE drivers,
+ * and in Softirqs/Tasklets/BH context by the SCSI drivers.
+ * Try to get the locking right :)
+ *
+ */
+
+
+/* About the global_state_lock
+ Each state transition on an device holds a read lock. In case we have
+ to evaluate the sync after dependencies, we grab a write lock, because
+ we need stable states on all devices for that. */
+rwlock_t global_state_lock;
+
+/* used for synchronous meta data and bitmap IO
+ * submitted by drbd_md_sync_page_io()
+ */
+void drbd_md_io_complete(struct bio *bio, int error)
+{
+ struct drbd_md_io *md_io;
+
+ /* error parameter ignored:
+ * drbd_md_sync_page_io explicitly tests bio_uptodate(bio); */
+
+ md_io = (struct drbd_md_io *)bio->bi_private;
+
+ md_io->error = error;
+
+ dump_internal_bio("Md", md_io->mdev, bio, 1);
+
+ complete(&md_io->event);
+}
+
+/* reads on behalf of the partner,
+ * "submitted" by the receiver
+ */
+void drbd_endio_read_sec(struct bio *bio, int error) __releases(local)
+{
+ unsigned long flags = 0;
+ struct Tl_epoch_entry *e = NULL;
+ struct drbd_conf *mdev;
+ int uptodate = bio_flagged(bio, BIO_UPTODATE);
+
+ e = bio->bi_private;
+ mdev = e->mdev;
+
+ if (!error && !uptodate) {
+ /* strange behaviour of some lower level drivers...
+ * fail the request by clearing the uptodate flag,
+ * but do not return any error?!
+ * do we want to drbd_WARN() on this? */
+ error = -EIO;
+ }
+
+ D_ASSERT(e->block_id != ID_VACANT);
+
+ dump_internal_bio("Sec", mdev, bio, 1);
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ mdev->read_cnt += e->size >> 9;
+ list_del(&e->w.list);
+ if (list_empty(&mdev->read_ee))
+ wake_up(&mdev->ee_wait);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ drbd_chk_io_error(mdev, error, FALSE);
+ drbd_queue_work(&mdev->data.work, &e->w);
+ dec_local(mdev);
+
+ MTRACE(TraceTypeEE, TraceLvlAll,
+ INFO("Moved EE (READ) to worker sec=%llus size=%u ee=%p\n",
+ (unsigned long long)e->sector, e->size, e);
+ );
+}
+
+/* writes on behalf of the partner, or resync writes,
+ * "submitted" by the receiver.
+ */
+void drbd_endio_write_sec(struct bio *bio, int error) __releases(local)
+{
+ unsigned long flags = 0;
+ struct Tl_epoch_entry *e = NULL;
+ struct drbd_conf *mdev;
+ sector_t e_sector;
+ int do_wake;
+ int is_syncer_req;
+ int do_al_complete_io;
+ int uptodate = bio_flagged(bio, BIO_UPTODATE);
+
+ e = bio->bi_private;
+ mdev = e->mdev;
+
+ if (!error && !uptodate) {
+ /* strange behaviour of some lower level drivers...
+ * fail the request by clearing the uptodate flag,
+ * but do not return any error?!
+ * do we want to drbd_WARN() on this? */
+ error = -EIO;
+ }
+
+ /* error == -ENOTSUPP would be a better test,
+ * alas it is not reliable */
+ if (error && e->flags & EE_IS_BARRIER) {
+ drbd_bump_write_ordering(mdev, WO_bdev_flush);
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ list_del(&e->w.list);
+ e->w.cb = w_e_reissue;
+ __release(local); /* Actually happens in w_e_reissue. */
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+ drbd_queue_work(&mdev->data.work, &e->w);
+ return;
+ }
+
+ D_ASSERT(e->block_id != ID_VACANT);
+
+ dump_internal_bio("Sec", mdev, bio, 1);
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ mdev->writ_cnt += e->size >> 9;
+ is_syncer_req = is_syncer_block_id(e->block_id);
+
+ /* after we moved e to done_ee,
+ * we may no longer access it,
+ * it may be freed/reused already!
+ * (as soon as we release the req_lock) */
+ e_sector = e->sector;
+ do_al_complete_io = e->flags & EE_CALL_AL_COMPLETE_IO;
+
+ list_del(&e->w.list); /* has been on active_ee or sync_ee */
+ list_add_tail(&e->w.list, &mdev->done_ee);
+
+ MTRACE(TraceTypeEE, TraceLvlAll,
+ INFO("Moved EE (WRITE) to done_ee sec=%llus size=%u ee=%p\n",
+ (unsigned long long)e->sector, e->size, e);
+ );
+
+ /* No hlist_del_init(&e->colision) here, we did not send the Ack yet,
+ * neither did we wake possibly waiting conflicting requests.
+ * done from "drbd_process_done_ee" within the appropriate w.cb
+ * (e_end_block/e_end_resync_block) or from _drbd_clear_done_ee */
+
+ do_wake = is_syncer_req
+ ? list_empty(&mdev->sync_ee)
+ : list_empty(&mdev->active_ee);
+
+ if (error)
+ __drbd_chk_io_error(mdev, FALSE);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ if (is_syncer_req)
+ drbd_rs_complete_io(mdev, e_sector);
+
+ if (do_wake)
+ wake_up(&mdev->ee_wait);
+
+ if (do_al_complete_io)
+ drbd_al_complete_io(mdev, e_sector);
+
+ wake_asender(mdev);
+ dec_local(mdev);
+
+}
+
+/* read, readA or write requests on Primary comming from drbd_make_request
+ */
+void drbd_endio_pri(struct bio *bio, int error)
+{
+ unsigned long flags;
+ struct drbd_request *req = bio->bi_private;
+ struct drbd_conf *mdev = req->mdev;
+ enum drbd_req_event what;
+ int uptodate = bio_flagged(bio, BIO_UPTODATE);
+
+ if (!error && !uptodate) {
+ /* strange behaviour of some lower level drivers...
+ * fail the request by clearing the uptodate flag,
+ * but do not return any error?!
+ * do we want to drbd_WARN() on this? */
+ error = -EIO;
+ }
+
+ dump_internal_bio("Pri", mdev, bio, 1);
+
+ /* to avoid recursion in _req_mod */
+ what = error
+ ? (bio_data_dir(bio) == WRITE)
+ ? write_completed_with_error
+ : read_completed_with_error
+ : completed_ok;
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ _req_mod(req, what, error);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+}
+
+int w_io_error(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct drbd_request *req = (struct drbd_request *)w;
+ int ok;
+
+ /* NOTE: mdev->bc can be NULL by the time we get here! */
+ /* D_ASSERT(mdev->bc->dc.on_io_error != PassOn); */
+
+ /* the only way this callback is scheduled is from _req_may_be_done,
+ * when it is done and had a local write error, see comments there */
+ drbd_req_free(req);
+
+ ok = drbd_io_error(mdev, FALSE);
+ if (unlikely(!ok))
+ ERR("Sending in w_io_error() failed\n");
+ return ok;
+}
+
+int w_read_retry_remote(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct drbd_request *req = (struct drbd_request *)w;
+
+ /* We should not detach for read io-error,
+ * but try to WRITE the DataReply to the failed location,
+ * to give the disk the chance to relocate that block */
+ drbd_io_error(mdev, FALSE); /* tries to schedule a detach and notifies peer */
+
+ spin_lock_irq(&mdev->req_lock);
+ if (cancel ||
+ mdev->state.conn < Connected ||
+ mdev->state.pdsk <= Inconsistent) {
+ _req_mod(req, send_canceled, 0);
+ spin_unlock_irq(&mdev->req_lock);
+ ALERT("WE ARE LOST. Local IO failure, no peer.\n");
+ return 1;
+ }
+ spin_unlock_irq(&mdev->req_lock);
+
+ return w_send_read_req(mdev, w, 0);
+}
+
+int w_resync_inactive(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ ERR_IF(cancel) return 1;
+ ERR("resync inactive, but callback triggered??\n");
+ return 1; /* Simply ignore this! */
+}
+
+STATIC void drbd_csum(struct drbd_conf *mdev, struct crypto_hash *tfm, struct bio *bio, void *digest)
+{
+ struct hash_desc desc;
+ struct scatterlist sg;
+ struct bio_vec *bvec;
+ int i;
+
+ desc.tfm = tfm;
+ desc.flags = 0;
+
+ sg_init_table(&sg, 1);
+ crypto_hash_init(&desc);
+
+ __bio_for_each_segment(bvec, bio, i, 0) {
+ sg_set_page(&sg, bvec->bv_page, bvec->bv_len, bvec->bv_offset);
+ crypto_hash_update(&desc, &sg, sg.length);
+ }
+ crypto_hash_final(&desc, digest);
+}
+
+STATIC int w_e_send_csum(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct Tl_epoch_entry *e = (struct Tl_epoch_entry *)w;
+ int digest_size;
+ void *digest;
+ int ok;
+
+ D_ASSERT(e->block_id == DRBD_MAGIC + 0xbeef);
+
+ if (unlikely(cancel)) {
+ drbd_free_ee(mdev, e);
+ return 1;
+ }
+
+ if (likely(drbd_bio_uptodate(e->private_bio))) {
+ digest_size = crypto_hash_digestsize(mdev->csums_tfm);
+ digest = kmalloc(digest_size, GFP_KERNEL);
+ if (digest) {
+ drbd_csum(mdev, mdev->csums_tfm, e->private_bio, digest);
+
+ inc_rs_pending(mdev);
+ ok = drbd_send_drequest_csum(mdev,
+ e->sector,
+ e->size,
+ digest,
+ digest_size,
+ CsumRSRequest);
+ kfree(digest);
+ } else {
+ ERR("kmalloc() of digest failed.\n");
+ ok = 0;
+ }
+ } else {
+ drbd_io_error(mdev, FALSE);
+ ok = 1;
+ }
+
+ drbd_free_ee(mdev, e);
+
+ if (unlikely(!ok))
+ ERR("drbd_send_drequest(..., csum) failed\n");
+ return ok;
+}
+
+#define GFP_TRY (__GFP_HIGHMEM | __GFP_NOWARN)
+
+STATIC int read_for_csum(struct drbd_conf *mdev, sector_t sector, int size)
+{
+ struct Tl_epoch_entry *e;
+
+ if (!inc_local(mdev))
+ return 0;
+
+ if (FAULT_ACTIVE(mdev, DRBD_FAULT_AL_EE))
+ return 2;
+
+ e = drbd_alloc_ee(mdev, DRBD_MAGIC+0xbeef, sector, size, GFP_TRY);
+ if (!e) {
+ dec_local(mdev);
+ return 2;
+ }
+
+ spin_lock_irq(&mdev->req_lock);
+ list_add(&e->w.list, &mdev->read_ee);
+ spin_unlock_irq(&mdev->req_lock);
+
+ e->private_bio->bi_end_io = drbd_endio_read_sec;
+ e->private_bio->bi_rw = READ;
+ e->w.cb = w_e_send_csum;
+
+ mdev->read_cnt += size >> 9;
+ drbd_generic_make_request(mdev, DRBD_FAULT_RS_RD, e->private_bio);
+
+ return 1;
+}
+
+void resync_timer_fn(unsigned long data)
+{
+ unsigned long flags;
+ struct drbd_conf *mdev = (struct drbd_conf *) data;
+ int queue;
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+
+ if (likely(!test_and_clear_bit(STOP_SYNC_TIMER, &mdev->flags))) {
+ queue = 1;
+ if (mdev->state.conn == VerifyS)
+ mdev->resync_work.cb = w_make_ov_request;
+ else
+ mdev->resync_work.cb = w_make_resync_request;
+ } else {
+ queue = 0;
+ mdev->resync_work.cb = w_resync_inactive;
+ }
+
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ /* harmless race: list_empty outside data.work.q_lock */
+ if (list_empty(&mdev->resync_work.list) && queue)
+ drbd_queue_work(&mdev->data.work, &mdev->resync_work);
+}
+
+int w_make_resync_request(struct drbd_conf *mdev,
+ struct drbd_work *w, int cancel)
+{
+ unsigned long bit;
+ sector_t sector;
+ const sector_t capacity = drbd_get_capacity(mdev->this_bdev);
+ int max_segment_size = mdev->rq_queue->max_segment_size;
+ int number, i, size;
+ int align;
+
+ if (unlikely(cancel))
+ return 1;
+
+ if (unlikely(mdev->state.conn < Connected)) {
+ ERR("Confused in w_make_resync_request()! cstate < Connected");
+ return 0;
+ }
+
+ if (mdev->state.conn != SyncTarget)
+ ERR("%s in w_make_resync_request\n",
+ conns_to_name(mdev->state.conn));
+
+ if (!inc_local(mdev)) {
+ /* Since we only need to access mdev->rsync a
+ inc_local_if_state(mdev,Failed) would be sufficient, but
+ to continue resync with a broken disk makes no sense at
+ all */
+ ERR("Disk broke down during resync!\n");
+ mdev->resync_work.cb = w_resync_inactive;
+ return 1;
+ }
+ /* All goto requeses have to happend after this block: inc_local() */
+
+ number = SLEEP_TIME*mdev->sync_conf.rate / ((BM_BLOCK_SIZE/1024)*HZ);
+
+ if (atomic_read(&mdev->rs_pending_cnt) > number)
+ goto requeue;
+ number -= atomic_read(&mdev->rs_pending_cnt);
+
+ for (i = 0; i < number; i++) {
+next_sector:
+ size = BM_BLOCK_SIZE;
+ bit = drbd_bm_find_next(mdev, mdev->bm_resync_fo);
+
+ if (bit == -1UL) {
+ mdev->bm_resync_fo = drbd_bm_bits(mdev);
+ mdev->resync_work.cb = w_resync_inactive;
+ dec_local(mdev);
+ return 1;
+ }
+
+ sector = BM_BIT_TO_SECT(bit);
+
+ if (drbd_try_rs_begin_io(mdev, sector)) {
+ mdev->bm_resync_fo = bit;
+ goto requeue;
+ }
+ mdev->bm_resync_fo = bit + 1;
+
+ if (unlikely(drbd_bm_test_bit(mdev, bit) == 0)) {
+ drbd_rs_complete_io(mdev, sector);
+ goto next_sector;
+ }
+
+#if DRBD_MAX_SEGMENT_SIZE > BM_BLOCK_SIZE
+ /* try to find some adjacent bits.
+ * we stop if we have already the maximum req size.
+ *
+ * Aditionally always align bigger requests, in order to
+ * be prepared for all stripe sizes of software RAIDs.
+ *
+ * we _do_ care about the agreed-uppon q->max_segment_size
+ * here, as splitting up the requests on the other side is more
+ * difficult. the consequence is, that on lvm and md and other
+ * "indirect" devices, this is dead code, since
+ * q->max_segment_size will be PAGE_SIZE.
+ */
+ align = 1;
+ for (;;) {
+ if (size + BM_BLOCK_SIZE > max_segment_size)
+ break;
+
+ /* Be always aligned */
+ if (sector & ((1<<(align+3))-1))
+ break;
+
+ /* do not cross extent boundaries */
+ if (((bit+1) & BM_BLOCKS_PER_BM_EXT_MASK) == 0)
+ break;
+ /* now, is it actually dirty, after all?
+ * caution, drbd_bm_test_bit is tri-state for some
+ * obscure reason; ( b == 0 ) would get the out-of-band
+ * only accidentally right because of the "oddly sized"
+ * adjustment below */
+ if (drbd_bm_test_bit(mdev, bit+1) != 1)
+ break;
+ bit++;
+ size += BM_BLOCK_SIZE;
+ if ((BM_BLOCK_SIZE << align) <= size)
+ align++;
+ i++;
+ }
+ /* if we merged some,
+ * reset the offset to start the next drbd_bm_find_next from */
+ if (size > BM_BLOCK_SIZE)
+ mdev->bm_resync_fo = bit + 1;
+#endif
+
+ /* adjust very last sectors, in case we are oddly sized */
+ if (sector + (size>>9) > capacity)
+ size = (capacity-sector)<<9;
+ if (mdev->agreed_pro_version >= 89 && mdev->csums_tfm) {
+ switch (read_for_csum(mdev, sector, size)) {
+ case 0: /* Disk failure*/
+ dec_local(mdev);
+ return 0;
+ case 2: /* Allocation failed */
+ drbd_rs_complete_io(mdev, sector);
+ mdev->bm_resync_fo = BM_SECT_TO_BIT(sector);
+ goto requeue;
+ /* case 1: everything ok */
+ }
+ } else {
+ inc_rs_pending(mdev);
+ if (!drbd_send_drequest(mdev, RSDataRequest,
+ sector, size, ID_SYNCER)) {
+ ERR("drbd_send_drequest() failed, aborting...\n");
+ dec_rs_pending(mdev);
+ dec_local(mdev);
+ return 0;
+ }
+ }
+ }
+
+ if (mdev->bm_resync_fo >= drbd_bm_bits(mdev)) {
+ /* last syncer _request_ was sent,
+ * but the RSDataReply not yet received. sync will end (and
+ * next sync group will resume), as soon as we receive the last
+ * resync data block, and the last bit is cleared.
+ * until then resync "work" is "inactive" ...
+ */
+ mdev->resync_work.cb = w_resync_inactive;
+ dec_local(mdev);
+ return 1;
+ }
+
+ requeue:
+ mod_timer(&mdev->resync_timer, jiffies + SLEEP_TIME);
+ dec_local(mdev);
+ return 1;
+}
+
+int w_make_ov_request(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ int number, i, size;
+ sector_t sector;
+ const sector_t capacity = drbd_get_capacity(mdev->this_bdev);
+
+ if (unlikely(cancel))
+ return 1;
+
+ if (unlikely(mdev->state.conn < Connected)) {
+ ERR("Confused in w_make_ov_request()! cstate < Connected");
+ return 0;
+ }
+
+ number = SLEEP_TIME*mdev->sync_conf.rate / ((BM_BLOCK_SIZE/1024)*HZ);
+ if (atomic_read(&mdev->rs_pending_cnt) > number)
+ goto requeue;
+
+ number -= atomic_read(&mdev->rs_pending_cnt);
+
+ sector = mdev->ov_position;
+ for (i = 0; i < number; i++) {
+ size = BM_BLOCK_SIZE;
+
+ if (drbd_try_rs_begin_io(mdev, sector)) {
+ mdev->ov_position = sector;
+ goto requeue;
+ }
+
+ if (sector + (size>>9) > capacity)
+ size = (capacity-sector)<<9;
+
+ inc_rs_pending(mdev);
+ if (!drbd_send_ov_request(mdev, sector, size)) {
+ dec_rs_pending(mdev);
+ return 0;
+ }
+ sector += BM_SECT_PER_BIT;
+ if (sector >= capacity) {
+ mdev->resync_work.cb = w_resync_inactive;
+
+ return 1;
+ }
+ }
+ mdev->ov_position = sector;
+
+ requeue:
+ mod_timer(&mdev->resync_timer, jiffies + SLEEP_TIME);
+ return 1;
+}
+
+
+int w_ov_finished(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ kfree(w);
+ ov_oos_print(mdev);
+ drbd_resync_finished(mdev);
+
+ return 1;
+}
+
+STATIC int w_resync_finished(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ kfree(w);
+
+ drbd_resync_finished(mdev);
+
+ return 1;
+}
+
+int drbd_resync_finished(struct drbd_conf *mdev)
+{
+ unsigned long db, dt, dbdt;
+ unsigned long n_oos;
+ union drbd_state_t os, ns;
+ struct drbd_work *w;
+ char *khelper_cmd = NULL;
+
+ /* Remove all elements from the resync LRU. Since future actions
+ * might set bits in the (main) bitmap, then the entries in the
+ * resync LRU would be wrong. */
+ if (drbd_rs_del_all(mdev)) {
+ /* In case this is not possible now, most probabely because
+ * there are RSDataReply Packets lingering on the worker's
+ * queue (or even the read operations for those packets
+ * is not finished by now). Retry in 100ms. */
+
+ drbd_kick_lo(mdev);
+ __set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(HZ / 10);
+ w = kmalloc(sizeof(struct drbd_work), GFP_ATOMIC);
+ if (w) {
+ w->cb = w_resync_finished;
+ drbd_queue_work(&mdev->data.work, w);
+ return 1;
+ }
+ ERR("Warn failed to drbd_rs_del_all() and to kmalloc(w).\n");
+ }
+
+ dt = (jiffies - mdev->rs_start - mdev->rs_paused) / HZ;
+ if (dt <= 0)
+ dt = 1;
+ db = mdev->rs_total;
+ dbdt = Bit2KB(db/dt);
+ mdev->rs_paused /= HZ;
+
+ if (!inc_local(mdev))
+ goto out;
+
+ spin_lock_irq(&mdev->req_lock);
+ os = mdev->state;
+
+ /* This protects us against multiple calls (that can happen in the presence
+ of application IO), and against connectivity loss just before we arrive here. */
+ if (os.conn <= Connected)
+ goto out_unlock;
+
+ ns = os;
+ ns.conn = Connected;
+
+ INFO("%s done (total %lu sec; paused %lu sec; %lu K/sec)\n",
+ (os.conn == VerifyS || os.conn == VerifyT) ?
+ "Online verify " : "Resync",
+ dt + mdev->rs_paused, mdev->rs_paused, dbdt);
+
+ n_oos = drbd_bm_total_weight(mdev);
+
+ if (os.conn == VerifyS || os.conn == VerifyT) {
+ if (n_oos) {
+ ALERT("Online verify found %lu %dk block out of sync!\n",
+ n_oos, Bit2KB(1));
+ khelper_cmd = "out-of-sync";
+ }
+ } else {
+ D_ASSERT((n_oos - mdev->rs_failed) == 0);
+
+ if (os.conn == SyncTarget || os.conn == PausedSyncT)
+ khelper_cmd = "after-resync-target";
+
+ if (mdev->csums_tfm && mdev->rs_total) {
+ const unsigned long s = mdev->rs_same_csum;
+ const unsigned long t = mdev->rs_total;
+ const int ratio =
+ (t == 0) ? 0 :
+ (t < 100000) ? ((s*100)/t) : (s/(t/100));
+ INFO("%u %% had equal check sums, eliminated: %luK; "
+ "transferred %luK total %luK\n",
+ ratio,
+ Bit2KB(mdev->rs_same_csum),
+ Bit2KB(mdev->rs_total - mdev->rs_same_csum),
+ Bit2KB(mdev->rs_total));
+ }
+ }
+
+ if (mdev->rs_failed) {
+ INFO(" %lu failed blocks\n", mdev->rs_failed);
+
+ if (os.conn == SyncTarget || os.conn == PausedSyncT) {
+ ns.disk = Inconsistent;
+ ns.pdsk = UpToDate;
+ } else {
+ ns.disk = UpToDate;
+ ns.pdsk = Inconsistent;
+ }
+ } else {
+ ns.disk = UpToDate;
+ ns.pdsk = UpToDate;
+
+ if (os.conn == SyncTarget || os.conn == PausedSyncT) {
+ if (mdev->p_uuid) {
+ int i;
+ for (i = Bitmap ; i <= History_end ; i++)
+ _drbd_uuid_set(mdev, i, mdev->p_uuid[i]);
+ drbd_uuid_set(mdev, Bitmap, mdev->bc->md.uuid[Current]);
+ _drbd_uuid_set(mdev, Current, mdev->p_uuid[Current]);
+ } else {
+ ERR("mdev->p_uuid is NULL! BUG\n");
+ }
+ }
+
+ drbd_uuid_set_bm(mdev, 0UL);
+
+ if (mdev->p_uuid) {
+ /* Now the two UUID sets are equal, update what we
+ * know of the peer. */
+ int i;
+ for (i = Current ; i <= History_end ; i++)
+ mdev->p_uuid[i] = mdev->bc->md.uuid[i];
+ }
+ }
+
+ _drbd_set_state(mdev, ns, ChgStateVerbose, NULL);
+out_unlock:
+ spin_unlock_irq(&mdev->req_lock);
+ dec_local(mdev);
+out:
+ mdev->rs_total = 0;
+ mdev->rs_failed = 0;
+ mdev->rs_paused = 0;
+
+ if (test_and_clear_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags)) {
+ drbd_WARN("Writing the whole bitmap, due to failed kmalloc\n");
+ drbd_queue_bitmap_io(mdev, &drbd_bm_write, NULL, "write from resync_finished");
+ }
+
+ drbd_bm_recount_bits(mdev);
+
+ if (khelper_cmd)
+ drbd_khelper(mdev, khelper_cmd);
+
+ return 1;
+}
+
+/**
+ * w_e_end_data_req: Send the answer (DataReply) in response to a DataRequest.
+ */
+int w_e_end_data_req(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct Tl_epoch_entry *e = (struct Tl_epoch_entry *)w;
+ int ok;
+
+ if (unlikely(cancel)) {
+ drbd_free_ee(mdev, e);
+ dec_unacked(mdev);
+ return 1;
+ }
+
+ if (likely(drbd_bio_uptodate(e->private_bio))) {
+ ok = drbd_send_block(mdev, DataReply, e);
+ } else {
+ if (__ratelimit(&drbd_ratelimit_state))
+ ERR("Sending NegDReply. sector=%llus.\n",
+ (unsigned long long)e->sector);
+
+ ok = drbd_send_ack(mdev, NegDReply, e);
+
+ drbd_io_error(mdev, FALSE);
+ }
+
+ dec_unacked(mdev);
+
+ spin_lock_irq(&mdev->req_lock);
+ if (drbd_bio_has_active_page(e->private_bio)) {
+ /* This might happen if sendpage() has not finished */
+ list_add_tail(&e->w.list, &mdev->net_ee);
+ } else {
+ drbd_free_ee(mdev, e);
+ }
+ spin_unlock_irq(&mdev->req_lock);
+
+ if (unlikely(!ok))
+ ERR("drbd_send_block() failed\n");
+ return ok;
+}
+
+/**
+ * w_e_end_rsdata_req: Send the answer (RSDataReply) to a RSDataRequest.
+ */
+int w_e_end_rsdata_req(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct Tl_epoch_entry *e = (struct Tl_epoch_entry *)w;
+ int ok;
+
+ if (unlikely(cancel)) {
+ drbd_free_ee(mdev, e);
+ dec_unacked(mdev);
+ return 1;
+ }
+
+ if (inc_local_if_state(mdev, Failed)) {
+ drbd_rs_complete_io(mdev, e->sector);
+ dec_local(mdev);
+ }
+
+ if (likely(drbd_bio_uptodate(e->private_bio))) {
+ if (likely(mdev->state.pdsk >= Inconsistent)) {
+ inc_rs_pending(mdev);
+ ok = drbd_send_block(mdev, RSDataReply, e);
+ } else {
+ if (__ratelimit(&drbd_ratelimit_state))
+ ERR("Not sending RSDataReply, "
+ "partner DISKLESS!\n");
+ ok = 1;
+ }
+ } else {
+ if (__ratelimit(&drbd_ratelimit_state))
+ ERR("Sending NegRSDReply. sector %llus.\n",
+ (unsigned long long)e->sector);
+
+ ok = drbd_send_ack(mdev, NegRSDReply, e);
+
+ drbd_io_error(mdev, FALSE);
+
+ /* update resync data with failure */
+ drbd_rs_failed_io(mdev, e->sector, e->size);
+ }
+
+ dec_unacked(mdev);
+
+ spin_lock_irq(&mdev->req_lock);
+ if (drbd_bio_has_active_page(e->private_bio)) {
+ /* This might happen if sendpage() has not finished */
+ list_add_tail(&e->w.list, &mdev->net_ee);
+ } else {
+ drbd_free_ee(mdev, e);
+ }
+ spin_unlock_irq(&mdev->req_lock);
+
+ if (unlikely(!ok))
+ ERR("drbd_send_block() failed\n");
+ return ok;
+}
+
+int w_e_end_csum_rs_req(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct Tl_epoch_entry *e = (struct Tl_epoch_entry *)w;
+ struct digest_info *di;
+ int digest_size;
+ void *digest = NULL;
+ int ok, eq = 0;
+
+ if (unlikely(cancel)) {
+ drbd_free_ee(mdev, e);
+ dec_unacked(mdev);
+ return 1;
+ }
+
+ drbd_rs_complete_io(mdev, e->sector);
+
+ di = (struct digest_info *)(unsigned long)e->block_id;
+
+ if (likely(drbd_bio_uptodate(e->private_bio))) {
+ /* quick hack to try to avoid a race against reconfiguration.
+ * a real fix would be much more involved,
+ * introducing more locking mechanisms */
+ if (mdev->csums_tfm) {
+ digest_size = crypto_hash_digestsize(mdev->csums_tfm);
+ D_ASSERT(digest_size == di->digest_size);
+ digest = kmalloc(digest_size, GFP_KERNEL);
+ }
+ if (digest) {
+ drbd_csum(mdev, mdev->csums_tfm, e->private_bio, digest);
+ eq = !memcmp(digest, di->digest, digest_size);
+ kfree(digest);
+ }
+
+ if (eq) {
+ drbd_set_in_sync(mdev, e->sector, e->size);
+ mdev->rs_same_csum++;
+ ok = drbd_send_ack(mdev, RSIsInSync, e);
+ } else {
+ inc_rs_pending(mdev);
+ e->block_id = ID_SYNCER;
+ ok = drbd_send_block(mdev, RSDataReply, e);
+ }
+ } else {
+ ok = drbd_send_ack(mdev, NegRSDReply, e);
+ if (__ratelimit(&drbd_ratelimit_state))
+ ERR("Sending NegDReply. I guess it gets messy.\n");
+ drbd_io_error(mdev, FALSE);
+ }
+
+ dec_unacked(mdev);
+
+ kfree(di);
+
+ spin_lock_irq(&mdev->req_lock);
+ if (drbd_bio_has_active_page(e->private_bio)) {
+ /* This might happen if sendpage() has not finished */
+ list_add_tail(&e->w.list, &mdev->net_ee);
+ } else {
+ drbd_free_ee(mdev, e);
+ }
+ spin_unlock_irq(&mdev->req_lock);
+
+ if (unlikely(!ok))
+ ERR("drbd_send_block/ack() failed\n");
+ return ok;
+}
+
+int w_e_end_ov_req(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct Tl_epoch_entry *e = (struct Tl_epoch_entry *)w;
+ int digest_size;
+ void *digest;
+ int ok = 1;
+
+ if (unlikely(cancel)) {
+ drbd_free_ee(mdev, e);
+ dec_unacked(mdev);
+ return 1;
+ }
+
+ if (likely(drbd_bio_uptodate(e->private_bio))) {
+ digest_size = crypto_hash_digestsize(mdev->verify_tfm);
+ digest = kmalloc(digest_size, GFP_KERNEL);
+ if (digest) {
+ drbd_csum(mdev, mdev->verify_tfm, e->private_bio, digest);
+ ok = drbd_send_drequest_csum(mdev, e->sector, e->size,
+ digest, digest_size, OVReply);
+ if (ok)
+ inc_rs_pending(mdev);
+ kfree(digest);
+ }
+ }
+
+ dec_unacked(mdev);
+
+ spin_lock_irq(&mdev->req_lock);
+ drbd_free_ee(mdev, e);
+ spin_unlock_irq(&mdev->req_lock);
+
+ return ok;
+}
+
+void drbd_ov_oos_found(struct drbd_conf *mdev, sector_t sector, int size)
+{
+ if (mdev->ov_last_oos_start + mdev->ov_last_oos_size == sector) {
+ mdev->ov_last_oos_size += size>>9;
+ } else {
+ mdev->ov_last_oos_start = sector;
+ mdev->ov_last_oos_size = size>>9;
+ }
+ drbd_set_out_of_sync(mdev, sector, size);
+ set_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags);
+}
+
+int w_e_end_ov_reply(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct Tl_epoch_entry *e = (struct Tl_epoch_entry *)w;
+ struct digest_info *di;
+ int digest_size;
+ void *digest;
+ int ok, eq = 0;
+
+ if (unlikely(cancel)) {
+ drbd_free_ee(mdev, e);
+ dec_unacked(mdev);
+ return 1;
+ }
+
+ /* after "cancel", because after drbd_disconnect/drbd_rs_cancel_all
+ * the resync lru has been cleaned up already */
+ drbd_rs_complete_io(mdev, e->sector);
+
+ di = (struct digest_info *)(unsigned long)e->block_id;
+
+ if (likely(drbd_bio_uptodate(e->private_bio))) {
+ digest_size = crypto_hash_digestsize(mdev->verify_tfm);
+ digest = kmalloc(digest_size, GFP_KERNEL);
+ if (digest) {
+ drbd_csum(mdev, mdev->verify_tfm, e->private_bio, digest);
+
+ D_ASSERT(digest_size == di->digest_size);
+ eq = !memcmp(digest, di->digest, digest_size);
+ kfree(digest);
+ }
+ } else {
+ ok = drbd_send_ack(mdev, NegRSDReply, e);
+ if (__ratelimit(&drbd_ratelimit_state))
+ ERR("Sending NegDReply. I guess it gets messy.\n");
+ drbd_io_error(mdev, FALSE);
+ }
+
+ dec_unacked(mdev);
+
+ kfree(di);
+
+ if (!eq)
+ drbd_ov_oos_found(mdev, e->sector, e->size);
+ else
+ ov_oos_print(mdev);
+
+ ok = drbd_send_ack_ex(mdev, OVResult, e->sector, e->size,
+ eq ? ID_IN_SYNC : ID_OUT_OF_SYNC);
+
+ spin_lock_irq(&mdev->req_lock);
+ drbd_free_ee(mdev, e);
+ spin_unlock_irq(&mdev->req_lock);
+
+ if (--mdev->ov_left == 0) {
+ ov_oos_print(mdev);
+ drbd_resync_finished(mdev);
+ }
+
+ return ok;
+}
+
+int w_prev_work_done(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ clear_bit(WORK_PENDING, &mdev->flags);
+ wake_up(&mdev->misc_wait);
+ return 1;
+}
+
+int w_send_barrier(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct drbd_barrier *b = (struct drbd_barrier *)w;
+ struct Drbd_Barrier_Packet *p = &mdev->data.sbuf.Barrier;
+ int ok = 1;
+
+ /* really avoid racing with tl_clear. w.cb may have been referenced
+ * just before it was reassigned and requeued, so double check that.
+ * actually, this race was harmless, since we only try to send the
+ * barrier packet here, and otherwise do nothing with the object.
+ * but compare with the head of w_clear_epoch */
+ spin_lock_irq(&mdev->req_lock);
+ if (w->cb != w_send_barrier || mdev->state.conn < Connected)
+ cancel = 1;
+ spin_unlock_irq(&mdev->req_lock);
+ if (cancel)
+ return 1;
+
+ if (!drbd_get_data_sock(mdev))
+ return 0;
+ p->barrier = b->br_number;
+ /* inc_ap_pending was done where this was queued.
+ * dec_ap_pending will be done in got_BarrierAck
+ * or (on connection loss) in w_clear_epoch. */
+ ok = _drbd_send_cmd(mdev, mdev->data.socket, Barrier,
+ (struct Drbd_Header *)p, sizeof(*p), 0);
+ drbd_put_data_sock(mdev);
+
+ return ok;
+}
+
+int w_send_write_hint(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ if (cancel)
+ return 1;
+ return drbd_send_short_cmd(mdev, UnplugRemote);
+}
+
+/**
+ * w_send_dblock: Send a mirrored write request.
+ */
+int w_send_dblock(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct drbd_request *req = (struct drbd_request *)w;
+ int ok;
+
+ if (unlikely(cancel)) {
+ req_mod(req, send_canceled, 0);
+ return 1;
+ }
+
+ ok = drbd_send_dblock(mdev, req);
+ req_mod(req, ok ? handed_over_to_network : send_failed, 0);
+
+ return ok;
+}
+
+/**
+ * w_send_read_req: Send a read requests.
+ */
+int w_send_read_req(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+ struct drbd_request *req = (struct drbd_request *)w;
+ int ok;
+
+ if (unlikely(cancel)) {
+ req_mod(req, send_canceled, 0);
+ return 1;
+ }
+
+ ok = drbd_send_drequest(mdev, DataRequest, req->sector, req->size,
+ (unsigned long)req);
+
+ if (!ok) {
+ /* ?? we set Timeout or BrokenPipe in drbd_send();
+ * so this is probably redundant */
+ if (mdev->state.conn >= Connected)
+ drbd_force_state(mdev, NS(conn, NetworkFailure));
+ }
+ req_mod(req, ok ? handed_over_to_network : send_failed, 0);
+
+ return ok;
+}
+
+STATIC int _drbd_may_sync_now(struct drbd_conf *mdev)
+{
+ struct drbd_conf *odev = mdev;
+
+ while (1) {
+ if (odev->sync_conf.after == -1)
+ return 1;
+ odev = minor_to_mdev(odev->sync_conf.after);
+ ERR_IF(!odev) return 1;
+ if ((odev->state.conn >= SyncSource &&
+ odev->state.conn <= PausedSyncT) ||
+ odev->state.aftr_isp || odev->state.peer_isp ||
+ odev->state.user_isp)
+ return 0;
+ }
+}
+
+/**
+ * _drbd_pause_after:
+ * Finds all devices that may not resync now, and causes them to
+ * pause their resynchronisation.
+ * Called from process context only (admin command and after_state_ch).
+ */
+STATIC int _drbd_pause_after(struct drbd_conf *mdev)
+{
+ struct drbd_conf *odev;
+ int i, rv = 0;
+
+ for (i = 0; i < minor_count; i++) {
+ odev = minor_to_mdev(i);
+ if (!odev)
+ continue;
+ if (odev->state.conn == StandAlone && odev->state.disk == Diskless)
+ continue;
+ if (!_drbd_may_sync_now(odev))
+ rv |= (__drbd_set_state(_NS(odev, aftr_isp, 1), ChgStateHard, NULL)
+ != SS_NothingToDo);
+ }
+
+ return rv;
+}
+
+/**
+ * _drbd_resume_next:
+ * Finds all devices that can resume resynchronisation
+ * process, and causes them to resume.
+ * Called from process context only (admin command and worker).
+ */
+STATIC int _drbd_resume_next(struct drbd_conf *mdev)
+{
+ struct drbd_conf *odev;
+ int i, rv = 0;
+
+ for (i = 0; i < minor_count; i++) {
+ odev = minor_to_mdev(i);
+ if (!odev)
+ continue;
+ if (odev->state.aftr_isp) {
+ if (_drbd_may_sync_now(odev))
+ rv |= (__drbd_set_state(_NS(odev, aftr_isp, 0),
+ ChgStateHard, NULL)
+ != SS_NothingToDo) ;
+ }
+ }
+ return rv;
+}
+
+void resume_next_sg(struct drbd_conf *mdev)
+{
+ write_lock_irq(&global_state_lock);
+ _drbd_resume_next(mdev);
+ write_unlock_irq(&global_state_lock);
+}
+
+void suspend_other_sg(struct drbd_conf *mdev)
+{
+ write_lock_irq(&global_state_lock);
+ _drbd_pause_after(mdev);
+ write_unlock_irq(&global_state_lock);
+}
+
+void drbd_alter_sa(struct drbd_conf *mdev, int na)
+{
+ int changes;
+
+ write_lock_irq(&global_state_lock);
+ mdev->sync_conf.after = na;
+
+ do {
+ changes = _drbd_pause_after(mdev);
+ changes |= _drbd_resume_next(mdev);
+ } while (changes);
+
+ write_unlock_irq(&global_state_lock);
+}
+
+/**
+ * drbd_start_resync:
+ * @side: Either SyncSource or SyncTarget
+ * Start the resync process. Called from process context only,
+ * either admin command or drbd_receiver.
+ * Note, this function might bring you directly into one of the
+ * PausedSync* states.
+ */
+void drbd_start_resync(struct drbd_conf *mdev, enum drbd_conns side)
+{
+ union drbd_state_t ns;
+ int r;
+
+ MTRACE(TraceTypeResync, TraceLvlSummary,
+ INFO("Resync starting: side=%s\n",
+ side == SyncTarget ? "SyncTarget" : "SyncSource");
+ );
+
+ drbd_bm_recount_bits(mdev);
+
+ /* In case a previous resync run was aborted by an IO error... */
+ drbd_rs_cancel_all(mdev);
+
+ if (side == SyncTarget) {
+ /* Since application IO was locked out during WFBitMapT and
+ WFSyncUUID we are still unmodified. Before going to SyncTarget
+ we check that we might make the data inconsistent. */
+ r = drbd_khelper(mdev, "before-resync-target");
+ r = (r >> 8) & 0xff;
+ if (r > 0) {
+ INFO("before-resync-target handler returned %d, "
+ "dropping connection.\n", r);
+ drbd_force_state(mdev, NS(conn, Disconnecting));
+ return;
+ }
+ }
+
+ drbd_state_lock(mdev);
+
+ if (!inc_local_if_state(mdev, Negotiating)) {
+ drbd_state_unlock(mdev);
+ return;
+ }
+
+ if (side == SyncTarget) {
+ mdev->bm_resync_fo = 0;
+ } else /* side == SyncSource */ {
+ u64 uuid;
+
+ get_random_bytes(&uuid, sizeof(u64));
+ drbd_uuid_set(mdev, Bitmap, uuid);
+ drbd_send_sync_uuid(mdev, uuid);
+
+ D_ASSERT(mdev->state.disk == UpToDate);
+ }
+
+ write_lock_irq(&global_state_lock);
+ ns = mdev->state;
+
+ ns.aftr_isp = !_drbd_may_sync_now(mdev);
+
+ ns.conn = side;
+
+ if (side == SyncTarget)
+ ns.disk = Inconsistent;
+ else /* side == SyncSource */
+ ns.pdsk = Inconsistent;
+
+ r = __drbd_set_state(mdev, ns, ChgStateVerbose, NULL);
+ ns = mdev->state;
+
+ if (ns.conn < Connected)
+ r = SS_UnknownError;
+
+ if (r == SS_Success) {
+ mdev->rs_total =
+ mdev->rs_mark_left = drbd_bm_total_weight(mdev);
+ mdev->rs_failed = 0;
+ mdev->rs_paused = 0;
+ mdev->rs_start =
+ mdev->rs_mark_time = jiffies;
+ mdev->rs_same_csum = 0;
+ _drbd_pause_after(mdev);
+ }
+ write_unlock_irq(&global_state_lock);
+ drbd_state_unlock(mdev);
+ dec_local(mdev);
+
+ if (r == SS_Success) {
+ INFO("Began resync as %s (will sync %lu KB [%lu bits set]).\n",
+ conns_to_name(ns.conn),
+ (unsigned long) mdev->rs_total << (BM_BLOCK_SIZE_B-10),
+ (unsigned long) mdev->rs_total);
+
+ if (mdev->rs_total == 0) {
+ drbd_resync_finished(mdev);
+ return;
+ }
+
+ if (ns.conn == SyncTarget) {
+ D_ASSERT(!test_bit(STOP_SYNC_TIMER, &mdev->flags));
+ mod_timer(&mdev->resync_timer, jiffies);
+ }
+
+ drbd_md_sync(mdev);
+ }
+}
+
+int drbd_worker(struct Drbd_thread *thi)
+{
+ struct drbd_conf *mdev = thi->mdev;
+ struct drbd_work *w = NULL;
+ LIST_HEAD(work_list);
+ int intr = 0, i;
+
+ sprintf(current->comm, "drbd%d_worker", mdev_to_minor(mdev));
+
+ while (get_t_state(thi) == Running) {
+ drbd_thread_current_set_cpu(mdev);
+
+ if (down_trylock(&mdev->data.work.s)) {
+ mutex_lock(&mdev->data.mutex);
+ if (mdev->data.socket && !mdev->net_conf->no_cork)
+ drbd_tcp_uncork(mdev->data.socket);
+ mutex_unlock(&mdev->data.mutex);
+
+ intr = down_interruptible(&mdev->data.work.s);
+
+ mutex_lock(&mdev->data.mutex);
+ if (mdev->data.socket && !mdev->net_conf->no_cork)
+ drbd_tcp_cork(mdev->data.socket);
+ mutex_unlock(&mdev->data.mutex);
+ }
+
+ if (intr) {
+ D_ASSERT(intr == -EINTR);
+ flush_signals(current);
+ ERR_IF (get_t_state(thi) == Running)
+ continue;
+ break;
+ }
+
+ if (get_t_state(thi) != Running)
+ break;
+ /* With this break, we have done a down() but not consumed
+ the entry from the list. The cleanup code takes care of
+ this... */
+
+ w = NULL;
+ spin_lock_irq(&mdev->data.work.q_lock);
+ ERR_IF(list_empty(&mdev->data.work.q)) {
+ /* something terribly wrong in our logic.
+ * we were able to down() the semaphore,
+ * but the list is empty... doh.
+ *
+ * what is the best thing to do now?
+ * try again from scratch, restarting the receiver,
+ * asender, whatnot? could break even more ugly,
+ * e.g. when we are primary, but no good local data.
+ *
+ * I'll try to get away just starting over this loop.
+ */
+ spin_unlock_irq(&mdev->data.work.q_lock);
+ continue;
+ }
+ w = list_entry(mdev->data.work.q.next, struct drbd_work, list);
+ list_del_init(&w->list);
+ spin_unlock_irq(&mdev->data.work.q_lock);
+
+ if (!w->cb(mdev, w, mdev->state.conn < Connected)) {
+ /* drbd_WARN("worker: a callback failed! \n"); */
+ if (mdev->state.conn >= Connected)
+ drbd_force_state(mdev,
+ NS(conn, NetworkFailure));
+ }
+ }
+
+ spin_lock_irq(&mdev->data.work.q_lock);
+ i = 0;
+ while (!list_empty(&mdev->data.work.q)) {
+ list_splice_init(&mdev->data.work.q, &work_list);
+ spin_unlock_irq(&mdev->data.work.q_lock);
+
+ while (!list_empty(&work_list)) {
+ w = list_entry(work_list.next, struct drbd_work, list);
+ list_del_init(&w->list);
+ w->cb(mdev, w, 1);
+ i++; /* dead debugging code */
+ }
+
+ spin_lock_irq(&mdev->data.work.q_lock);
+ }
+ sema_init(&mdev->data.work.s, 0);
+ /* DANGEROUS race: if someone did queue his work within the spinlock,
+ * but up() ed outside the spinlock, we could get an up() on the
+ * semaphore without corresponding list entry.
+ * So don't do that.
+ */
+ spin_unlock_irq(&mdev->data.work.q_lock);
+
+ D_ASSERT(mdev->state.disk == Diskless && mdev->state.conn == StandAlone);
+ /* _drbd_set_state only uses stop_nowait.
+ * wait here for the Exiting receiver. */
+ drbd_thread_stop(&mdev->receiver);
+ drbd_mdev_cleanup(mdev);
+
+ INFO("worker terminated\n");
+
+ return 0;
+}