drbd/update-to-8.4.6-5.patch

diff --git a/ChangeLog b/ChangeLog
index 47d535d..eddc3a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,14 @@
 Latest:
 ------
- For even more detail, use "git log" or visit http://git.drbd.org/.
+ For even more detail, visit http://git.linbit.com/drbd-8.4.git
+
+ * fix latency regression introduced with 8.4.5
+   protocol A was sometimes synchronous, C sometimes double-latency
+ * avoid potential deadlock during handshake
+ * avoid potential deadlock in disconnect during resync
+   with fencing resource-and-stonith
+ * allow IO during some bitmap bulk IO operations
+ * fix "endless" transfer log walk in protocol A
 
 8.4.6 (api:genl1/proto:86-101)
 -------
diff --git a/drbd-kernel.spec b/drbd-kernel.spec
index 489b09f..9b70767 100644
--- a/drbd-kernel.spec
+++ b/drbd-kernel.spec
@@ -1,7 +1,7 @@
 Name: drbd-kernel
 Summary: Kernel driver for DRBD
 Version: 8.4.6
-Release: 1%{?dist}
+Release: 5%{?dist}
 Source: http://oss.linbit.com/drbd/drbd-%{version}.tar.gz
 License: GPLv2+
 Group: System Environment/Kernel
@@ -97,6 +97,12 @@ echo "override drbd * weak-updates" \
 rm -rf %{buildroot}
 
 %changelog
+* Wed Sep 16 2015  Lars Ellenberg <lars@linbit.com> - 8.4.6-5
+- New upstream release.
+
+* Thu Jul 30 2015 Lars Ellenberg <lars@linbit.com> - 8.4.6-4
+- New upstream release.
+
 * Fri Apr  3 2015 Philipp Reisner <phil@linbit.com> - 8.4.6-1
 - New upstream release.
 
diff --git a/drbd-km.spec b/drbd-km.spec
index 859aa51..0cb976d 100644
--- a/drbd-km.spec
+++ b/drbd-km.spec
@@ -10,7 +10,7 @@
 Name: drbd-km
 Summary: DRBD driver for Linux
 Version: 8.4.6
-Release: 1
+Release: 5
 Source: http://oss.linbit.com/%{name}/8.4/drbd-%{version}.tar.gz
 License: GPLv2+
 ExclusiveOS: linux
@@ -32,7 +32,7 @@ setting up high availability (HA) clusters.
 Summary: Kernel driver for DRBD.
 Group: System Environment/Kernel
 # always require a suitable userland and depmod.
-Requires: drbd-utils = %{version}, /sbin/depmod
+Requires: drbd-utils >= 8.9.2, /sbin/depmod
 # to be able to override from build scripts which flavor of kernel we are building against.
 Requires: %{expand: %(echo ${DRBD_KMOD_REQUIRES:-kernel})}
 # TODO: break up this generic .spec file into per distribution ones,
@@ -92,6 +92,12 @@ uname -r | grep BOOT ||
 
 
 %changelog
+* Wed Sep 16 2015  Lars Ellenberg <lars@linbit.com> - 8.4.6-5
+- New upstream release.
+
+* Thu Jul 30 2015 Lars Ellenberg <lars@linbit.com> - 8.4.6-4
+- New upstream release.
+
 * Fri Apr  3 2015 Philipp Reisner <phil@linbit.com> - 8.4.6-1
 - New upstream release.
 
diff --git a/drbd/compat/tests/have_WB_congested_enum.c b/drbd/compat/tests/have_WB_congested_enum.c
new file mode 100644
index 0000000..37fb32d
--- /dev/null
+++ b/drbd/compat/tests/have_WB_congested_enum.c
@@ -0,0 +1,13 @@
+#include <linux/backing-dev.h>
+
+
+/* With commit 4452226 (linux v4.2)
+   BDI_async_congested was renamed to WB_async_congested and
+   BDI_sync_congested was renamed to WB_sync_congested.
+   */
+
+void foo(void)
+{
+	int a = WB_async_congested;
+	int b = WB_sync_congested;
+}
diff --git a/drbd/compat/tests/have_generic_start_io_acct.c b/drbd/compat/tests/have_generic_start_io_acct.c
new file mode 100644
index 0000000..14a18d1
--- /dev/null
+++ b/drbd/compat/tests/have_generic_start_io_acct.c
@@ -0,0 +1,8 @@
+#include <linux/bio.h>
+
+/* Introduced by mainline commit 394ffa503b, available since v3.19 */
+
+void foo(void)
+{
+	generic_start_io_acct(WRITE, 0, (struct hd_struct *) NULL);
+}
diff --git a/drbd/compat/tests/have_simple_positive.c b/drbd/compat/tests/have_simple_positive.c
new file mode 100644
index 0000000..410f157
--- /dev/null
+++ b/drbd/compat/tests/have_simple_positive.c
@@ -0,0 +1,8 @@
+#include <linux/dcache.h>
+
+/* Since dc3f4198e (linux v4.2) simple_positive is accessible for modules */
+
+void foo(void)
+{
+	int r = simple_positive((struct dentry *)NULL);
+}
diff --git a/drbd/compat/tests/sock_create_kern_has_five_parameters.c b/drbd/compat/tests/sock_create_kern_has_five_parameters.c
new file mode 100644
index 0000000..342af09
--- /dev/null
+++ b/drbd/compat/tests/sock_create_kern_has_five_parameters.c
@@ -0,0 +1,11 @@
+#include <linux/net.h>
+
+
+/* With commit eeb1bd5 (linux v4.2) a new parameter was inserted in
+   first position */
+
+void foo(void)
+{
+	int err;
+	err = sock_create_kern((struct net *)NULL, 0, 0, 0, (struct socket **)NULL);
+}
diff --git a/drbd/drbd_actlog.c b/drbd/drbd_actlog.c
index 00c7956..1a274c5 100644
--- a/drbd/drbd_actlog.c
+++ b/drbd/drbd_actlog.c
@@ -312,7 +312,162 @@ bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *
 	return need_transaction;
 }
 
-static int al_write_transaction(struct drbd_device *device);
+#if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
+/* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
+ * are still coupled, or assume too much about their relation.
+ * Code below will not work if this is violated.
+ * Will be cleaned up with some followup patch.
+ */
+# error FIXME
+#endif
+
+static unsigned int al_extent_to_bm_page(unsigned int al_enr)
+{
+	return al_enr >>
+		/* bit to page */
+		((PAGE_SHIFT + 3) -
+		/* al extent number to bit */
+		 (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
+}
+
+static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
+{
+	const unsigned int stripes = device->ldev->md.al_stripes;
+	const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
+
+	/* transaction number, modulo on-disk ring buffer wrap around */
+	unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
+
+	/* ... to aligned 4k on disk block */
+	t = ((t % stripes) * stripe_size_4kB) + t/stripes;
+
+	/* ... to 512 byte sector in activity log */
+	t *= 8;
+
+	/* ... plus offset to the on disk position */
+	return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
+}
+
+static int __al_write_transaction(struct drbd_device *device, struct al_transaction_on_disk *buffer)
+{
+	struct lc_element *e;
+	sector_t sector;
+	int i, mx;
+	unsigned extent_nr;
+	unsigned crc = 0;
+	int err = 0;
+
+	memset(buffer, 0, sizeof(*buffer));
+	buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
+	buffer->tr_number = cpu_to_be32(device->al_tr_number);
+
+	i = 0;
+
+	/* Even though no one can start to change this list
+	 * once we set the LC_LOCKED -- from drbd_al_begin_io(),
+	 * lc_try_lock_for_transaction() --, someone may still
+	 * be in the process of changing it. */
+	spin_lock_irq(&device->al_lock);
+	list_for_each_entry(e, &device->act_log->to_be_changed, list) {
+		if (i == AL_UPDATES_PER_TRANSACTION) {
+			i++;
+			break;
+		}
+		buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
+		buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
+		if (e->lc_number != LC_FREE)
+			drbd_bm_mark_for_writeout(device,
+					al_extent_to_bm_page(e->lc_number));
+		i++;
+	}
+	spin_unlock_irq(&device->al_lock);
+	BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
+
+	buffer->n_updates = cpu_to_be16(i);
+	for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
+		buffer->update_slot_nr[i] = cpu_to_be16(-1);
+		buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
+	}
+
+	buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
+	buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
+
+	mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
+		   device->act_log->nr_elements - device->al_tr_cycle);
+	for (i = 0; i < mx; i++) {
+		unsigned idx = device->al_tr_cycle + i;
+		extent_nr = lc_element_by_index(device->act_log, idx)->lc_number;
+		buffer->context[i] = cpu_to_be32(extent_nr);
+	}
+	for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
+		buffer->context[i] = cpu_to_be32(LC_FREE);
+
+	device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
+	if (device->al_tr_cycle >= device->act_log->nr_elements)
+		device->al_tr_cycle = 0;
+
+	sector = al_tr_number_to_on_disk_sector(device);
+
+	crc = crc32c(0, buffer, 4096);
+	buffer->crc32c = cpu_to_be32(crc);
+
+	if (drbd_bm_write_hinted(device))
+		err = -EIO;
+	else {
+		bool write_al_updates;
+		rcu_read_lock();
+		write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
+		rcu_read_unlock();
+		if (write_al_updates) {
+			if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) {
+				err = -EIO;
+				drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
+			} else {
+				device->al_tr_number++;
+				device->al_writ_cnt++;
+			}
+		}
+	}
+
+	return err;
+}
+
+static int al_write_transaction(struct drbd_device *device)
+{
+	struct al_transaction_on_disk *buffer;
+	int err;
+
+	if (!get_ldev(device)) {
+		drbd_err(device, "disk is %s, cannot start al transaction\n",
+			drbd_disk_str(device->state.disk));
+		return -EIO;
+	}
+
+	/* The bitmap write may have failed, causing a state change. */
+	if (device->state.disk < D_INCONSISTENT) {
+		drbd_err(device,
+			"disk is %s, cannot write al transaction\n",
+			drbd_disk_str(device->state.disk));
+		put_ldev(device);
+		return -EIO;
+	}
+
+	/* protects md_io_buffer, al_tr_cycle, ... */
+	buffer = drbd_md_get_buffer(device, __func__);
+	if (!buffer) {
+		drbd_err(device, "disk failed while waiting for md_io buffer\n");
+		put_ldev(device);
+		return -ENODEV;
+	}
+
+	err = __al_write_transaction(device, buffer);
+
+	drbd_md_put_buffer(device);
+	put_ldev(device);
+
+	return err;
+}
+
 
 void drbd_al_begin_io_commit(struct drbd_device *device)
 {
@@ -444,153 +599,6 @@ void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i)
 	wake_up(&device->al_wait);
 }
 
-#if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
-/* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
- * are still coupled, or assume too much about their relation.
- * Code below will not work if this is violated.
- * Will be cleaned up with some followup patch.
- */
-# error FIXME
-#endif
-
-static unsigned int al_extent_to_bm_page(unsigned int al_enr)
-{
-	return al_enr >>
-		/* bit to page */
-		((PAGE_SHIFT + 3) -
-		/* al extent number to bit */
-		 (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
-}
-
-static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
-{
-	const unsigned int stripes = device->ldev->md.al_stripes;
-	const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
-
-	/* transaction number, modulo on-disk ring buffer wrap around */
-	unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
-
-	/* ... to aligned 4k on disk block */
-	t = ((t % stripes) * stripe_size_4kB) + t/stripes;
-
-	/* ... to 512 byte sector in activity log */
-	t *= 8;
-
-	/* ... plus offset to the on disk position */
-	return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
-}
-
-int al_write_transaction(struct drbd_device *device)
-{
-	struct al_transaction_on_disk *buffer;
-	struct lc_element *e;
-	sector_t sector;
-	int i, mx;
-	unsigned extent_nr;
-	unsigned crc = 0;
-	int err = 0;
-
-	if (!get_ldev(device)) {
-		drbd_err(device, "disk is %s, cannot start al transaction\n",
-			drbd_disk_str(device->state.disk));
-		return -EIO;
-	}
-
-	/* The bitmap write may have failed, causing a state change. */
-	if (device->state.disk < D_INCONSISTENT) {
-		drbd_err(device,
-			"disk is %s, cannot write al transaction\n",
-			drbd_disk_str(device->state.disk));
-		put_ldev(device);
-		return -EIO;
-	}
-
-	/* protects md_io_buffer, al_tr_cycle, ... */
-	buffer = drbd_md_get_buffer(device, __func__);
-	if (!buffer) {
-		drbd_err(device, "disk failed while waiting for md_io buffer\n");
-		put_ldev(device);
-		return -ENODEV;
-	}
-
-	memset(buffer, 0, sizeof(*buffer));
-	buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
-	buffer->tr_number = cpu_to_be32(device->al_tr_number);
-
-	i = 0;
-
-	/* Even though no one can start to change this list
-	 * once we set the LC_LOCKED -- from drbd_al_begin_io(),
-	 * lc_try_lock_for_transaction() --, someone may still
-	 * be in the process of changing it. */
-	spin_lock_irq(&device->al_lock);
-	list_for_each_entry(e, &device->act_log->to_be_changed, list) {
-		if (i == AL_UPDATES_PER_TRANSACTION) {
-			i++;
-			break;
-		}
-		buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
-		buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
-		if (e->lc_number != LC_FREE)
-			drbd_bm_mark_for_writeout(device,
-					al_extent_to_bm_page(e->lc_number));
-		i++;
-	}
-	spin_unlock_irq(&device->al_lock);
-	BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
-
-	buffer->n_updates = cpu_to_be16(i);
-	for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
-		buffer->update_slot_nr[i] = cpu_to_be16(-1);
-		buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
-	}
-
-	buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
-	buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
-
-	mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
-		   device->act_log->nr_elements - device->al_tr_cycle);
-	for (i = 0; i < mx; i++) {
-		unsigned idx = device->al_tr_cycle + i;
-		extent_nr = lc_element_by_index(device->act_log, idx)->lc_number;
-		buffer->context[i] = cpu_to_be32(extent_nr);
-	}
-	for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
-		buffer->context[i] = cpu_to_be32(LC_FREE);
-
-	device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
-	if (device->al_tr_cycle >= device->act_log->nr_elements)
-		device->al_tr_cycle = 0;
-
-	sector = al_tr_number_to_on_disk_sector(device);
-
-	crc = crc32c(0, buffer, 4096);
-	buffer->crc32c = cpu_to_be32(crc);
-
-	if (drbd_bm_write_hinted(device))
-		err = -EIO;
-	else {
-		bool write_al_updates;
-		rcu_read_lock();
-		write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
-		rcu_read_unlock();
-		if (write_al_updates) {
-			if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) {
-				err = -EIO;
-				drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
-			} else {
-				device->al_tr_number++;
-				device->al_writ_cnt++;
-			}
-		}
-	}
-
-	drbd_md_put_buffer(device);
-	put_ldev(device);
-
-	return err;
-}
-
 static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
 {
 	int rv;
@@ -630,21 +638,24 @@ void drbd_al_shrink(struct drbd_device *device)
 	wake_up(&device->al_wait);
 }
 
-int drbd_initialize_al(struct drbd_device *device, void *buffer)
+int drbd_al_initialize(struct drbd_device *device, void *buffer)
 {
 	struct al_transaction_on_disk *al = buffer;
 	struct drbd_md *md = &device->ldev->md;
-	sector_t al_base = md->md_offset + md->al_offset;
 	int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
 	int i;
 
-	memset(al, 0, 4096);
-	al->magic = cpu_to_be32(DRBD_AL_MAGIC);
-	al->transaction_type = cpu_to_be16(AL_TR_INITIALIZED);
-	al->crc32c = cpu_to_be32(crc32c(0, al, 4096));
+	__al_write_transaction(device, al);
+	/* There may or may not have been a pending transaction. */
+	spin_lock_irq(&device->al_lock);
+	lc_committed(device->act_log);
+	spin_unlock_irq(&device->al_lock);
 
-	for (i = 0; i < al_size_4k; i++) {
-		int err = drbd_md_sync_page_io(device, device->ldev, al_base + i * 8, WRITE);
+	/* The rest of the transactions will have an empty "updates" list, and
+	 * are written out only to provide the context, and to initialize the
+	 * on-disk ring buffer. */
+	for (i = 1; i < al_size_4k; i++) {
+		int err = __al_write_transaction(device, al);
 		if (err)
 			return err;
 	}
diff --git a/drbd/drbd_debugfs.c b/drbd/drbd_debugfs.c
index da50b19..df9b4a8 100644
--- a/drbd/drbd_debugfs.c
+++ b/drbd/drbd_debugfs.c
@@ -429,14 +429,6 @@ static int in_flight_summary_show(struct seq_file *m, void *pos)
 #endif
 
 
-/* simple_positive(file->f_path.dentry) respectively debugfs_positive(),
- * but neither is "reachable" from here.
- * So we have our own inline version of it above.  :-( */
-static inline int debugfs_positive(struct dentry *dentry)
-{
-        return dentry->d_inode && !d_unhashed(dentry);
-}
-
 /* make sure at *open* time that the respective object won't go away. */
 static int drbd_single_open(struct file *file, int (*show)(struct seq_file *, void *),
 		                void *data, struct kref *kref,
@@ -454,7 +446,7 @@ static int drbd_single_open(struct file *file, int (*show)(struct seq_file *, vo
 	/* serialize with d_delete() */
 	mutex_lock(&parent->d_inode->i_mutex);
 	/* Make sure the object is still alive */
-	if (debugfs_positive(file->f_dentry)
+	if (simple_positive(file->f_dentry)
 	&& kref_get_unless_zero(kref))
 		ret = 0;
 	mutex_unlock(&parent->d_inode->i_mutex);
diff --git a/drbd/drbd_int.h b/drbd/drbd_int.h
index 08d6648..d1e2bc0 100644
--- a/drbd/drbd_int.h
+++ b/drbd/drbd_int.h
@@ -36,6 +36,9 @@
 #include <linux/crypto.h>
 #include <linux/tcp.h>
 #include <linux/mutex.h>
+#include <linux/major.h>
+#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/genhd.h>
 #include <linux/idr.h>
 #include <net/tcp.h>
@@ -98,14 +101,10 @@ extern int fault_devs;
 
 extern char usermode_helper[];
 
-#include <linux/major.h>
 #ifndef DRBD_MAJOR
 # define DRBD_MAJOR 147
 #endif
 
-#include <linux/blkdev.h>
-#include <linux/bio.h>
-
 /* This is used to stop/restart our threads.
  * Cannot use SIGTERM nor SIGKILL, since these
  * are sent out by init on runlevel changes
@@ -593,7 +592,6 @@ enum {
 
 	MD_NO_BARRIER,		/* meta data device does not support barriers,
 				   so don't even try */
-	SUSPEND_IO,		/* suspend application io */
 	BITMAP_IO,		/* suspend application io;
 				   once no more io in flight, start bitmap io */
 	BITMAP_IO_QUEUED,       /* Started bitmap IO */
@@ -986,6 +984,7 @@ struct drbd_device {
 	atomic_t rs_pending_cnt; /* RS request/data packets on the wire */
 	atomic_t unacked_cnt;	 /* Need to send replies for */
 	atomic_t local_cnt;	 /* Waiting for local completion */
+	atomic_t suspend_cnt;
 
 	/* Interval tree of pending local write requests */
 	struct rb_root read_requests;
@@ -1785,7 +1784,7 @@ extern int __drbd_change_sync(struct drbd_device *device, sector_t sector, int s
 #define drbd_rs_failed_io(device, sector, size) \
 	__drbd_change_sync(device, sector, size, RECORD_RS_FAILED)
 extern void drbd_al_shrink(struct drbd_device *device);
-extern int drbd_initialize_al(struct drbd_device *, void *);
+extern int drbd_al_initialize(struct drbd_device *, void *);
 
 /* drbd_nl.c */
 /* state info broadcast */
@@ -2376,7 +2375,7 @@ static inline bool may_inc_ap_bio(struct drbd_device *device)
 
 	if (drbd_suspended(device))
 		return false;
-	if (test_bit(SUSPEND_IO, &device->flags))
+	if (atomic_read(&device->suspend_cnt))
 		return false;
 
 	/* to avoid potential deadlock or bitmap corruption,
diff --git a/drbd/drbd_main.c b/drbd/drbd_main.c
index f41aa8a..31bf43f 100644
--- a/drbd/drbd_main.c
+++ b/drbd/drbd_main.c
@@ -2435,7 +2435,7 @@ static void drbd_cleanup(void)
  * @congested_data:	User data
  * @bdi_bits:		Bits the BDI flusher thread is currently interested in
  *
- * Returns 1<<BDI_async_congested and/or 1<<BDI_sync_congested if we are congested.
+ * Returns 1<<WB_async_congested and/or 1<<WB_sync_congested if we are congested.
  */
 static int drbd_congested(void *congested_data, int bdi_bits)
 {
@@ -2452,14 +2452,14 @@ static int drbd_congested(void *congested_data, int bdi_bits)
 	}
 
 	if (test_bit(CALLBACK_PENDING, &first_peer_device(device)->connection->flags)) {
-		r |= (1 << BDI_async_congested);
+		r |= (1 << WB_async_congested);
 		/* Without good local data, we would need to read from remote,
 		 * and that would need the worker thread as well, which is
 		 * currently blocked waiting for that usermode helper to
 		 * finish.
 		 */
 		if (!get_ldev_if_state(device, D_UP_TO_DATE))
-			r |= (1 << BDI_sync_congested);
+			r |= (1 << WB_sync_congested);
 		else
 			put_ldev(device);
 		r &= bdi_bits;
@@ -2475,9 +2475,9 @@ static int drbd_congested(void *congested_data, int bdi_bits)
 			reason = 'b';
 	}
 
-	if (bdi_bits & (1 << BDI_async_congested) &&
+	if (bdi_bits & (1 << WB_async_congested) &&
 	    test_bit(NET_CONGESTED, &first_peer_device(device)->connection->flags)) {
-		r |= (1 << BDI_async_congested);
+		r |= (1 << WB_async_congested);
 		reason = reason == 'b' ? 'a' : 'n';
 	}
 
@@ -3601,7 +3601,12 @@ static int w_bitmap_io(struct drbd_work *w, int unused)
 	struct bm_io_work *work = &device->bm_io_work;
 	int rv = -EIO;
 
-	D_ASSERT(device, atomic_read(&device->ap_bio_cnt) == 0);
+	if (work->flags != BM_LOCKED_CHANGE_ALLOWED) {
+		int cnt = atomic_read(&device->ap_bio_cnt);
+		if (cnt)
+			drbd_err(device, "FIXME: ap_bio_cnt %d, expected 0; queued for '%s'\n",
+					cnt, work->why);
+	}
 
 	if (get_ldev(device)) {
 		drbd_bm_lock(device, work->why, work->flags);
@@ -3659,7 +3664,9 @@ void drbd_queue_bitmap_io(struct drbd_device *device,
 
 	spin_lock_irq(&device->resource->req_lock);
 	set_bit(BITMAP_IO, &device->flags);
-	if (atomic_read(&device->ap_bio_cnt) == 0) {
+	/* don't wait for pending application IO if the caller indicates that
+	 * application IO does not conflict anyways. */
+	if (flags == BM_LOCKED_CHANGE_ALLOWED || atomic_read(&device->ap_bio_cnt) == 0) {
 		if (!test_and_set_bit(BITMAP_IO_QUEUED, &device->flags))
 			drbd_queue_work(&first_peer_device(device)->connection->sender_work,
 					&device->bm_io_work.w);
@@ -3679,18 +3686,20 @@ void drbd_queue_bitmap_io(struct drbd_device *device,
 int drbd_bitmap_io(struct drbd_device *device, int (*io_fn)(struct drbd_device *),
 		char *why, enum bm_flag flags)
 {
+	/* Only suspend io, if some operation is supposed to be locked out */
+	const bool do_suspend_io = flags & (BM_DONT_CLEAR|BM_DONT_SET|BM_DONT_TEST);
 	int rv;
 
 	D_ASSERT(device, current != first_peer_device(device)->connection->worker.task);
 
-	if ((flags & BM_LOCKED_SET_ALLOWED) == 0)
+	if (do_suspend_io)
 		drbd_suspend_io(device);
 
 	drbd_bm_lock(device, why, flags);
 	rv = io_fn(device);
 	drbd_bm_unlock(device);
 
-	if ((flags & BM_LOCKED_SET_ALLOWED) == 0)
+	if (do_suspend_io)
 		drbd_resume_io(device);
 
 	return rv;
diff --git a/drbd/drbd_nl.c b/drbd/drbd_nl.c
index 9c14cf3..bb7e1b0 100644
--- a/drbd/drbd_nl.c
+++ b/drbd/drbd_nl.c
@@ -903,9 +903,11 @@ char *ppsize(char *buf, unsigned long long size)
  * and can be long lived.
  * This changes an device->flag, is triggered by drbd internals,
  * and should be short-lived. */
+/* It needs to be a counter, since multiple threads might
+   independently suspend and resume IO. */
 void drbd_suspend_io(struct drbd_device *device)
 {
-	set_bit(SUSPEND_IO, &device->flags);
+	atomic_inc(&device->suspend_cnt);
 	if (drbd_suspended(device))
 		return;
 	wait_event(device->misc_wait, !atomic_read(&device->ap_bio_cnt));
@@ -913,8 +915,8 @@ void drbd_suspend_io(struct drbd_device *device)
 
 void drbd_resume_io(struct drbd_device *device)
 {
-	clear_bit(SUSPEND_IO, &device->flags);
-	wake_up(&device->misc_wait);
+	if (atomic_dec_and_test(&device->suspend_cnt))
+		wake_up(&device->misc_wait);
 }
 
 /**
@@ -927,27 +929,32 @@ void drbd_resume_io(struct drbd_device *device)
 enum determine_dev_size
 drbd_determine_dev_size(struct drbd_device *device, enum dds_flags flags, struct resize_parms *rs) __must_hold(local)
 {
-	sector_t prev_first_sect, prev_size; /* previous meta location */
-	sector_t la_size_sect, u_size;
+	struct md_offsets_and_sizes {
+		u64 last_agreed_sect;
+		u64 md_offset;
+		s32 al_offset;
+		s32 bm_offset;
+		u32 md_size_sect;
+
+		u32 al_stripes;
+		u32 al_stripe_size_4k;
+	} prev;
+	sector_t u_size, size;
 	struct drbd_md *md = &device->ldev->md;
-	u32 prev_al_stripe_size_4k;
-	u32 prev_al_stripes;
-	sector_t size;
 	char ppb[10];
 	void *buffer;
 
 	int md_moved, la_size_changed;
 	enum determine_dev_size rv = DS_UNCHANGED;
 
-	/* race:
-	 * application request passes inc_ap_bio,
-	 * but then cannot get an AL-reference.
-	 * this function later may wait on ap_bio_cnt == 0. -> deadlock.
+	/* We may change the on-disk offsets of our meta data below.  Lock out
+	 * anything that may cause meta data IO, to avoid acting on incomplete
+	 * layout changes or scribbling over meta data that is in the process
+	 * of being moved.
 	 *
-	 * to avoid that:
-	 * Suspend IO right here.
-	 * still lock the act_log to not trigger ASSERTs there.
-	 */
+	 * Move is not exactly correct, btw, currently we have all our meta
+	 * data in core memory, to "move" it we just write it all out, there
+	 * are no reads. */
 	drbd_suspend_io(device);
 	buffer = drbd_md_get_buffer(device, __func__); /* Lock meta-data IO */
 	if (!buffer) {
@@ -955,19 +962,17 @@ drbd_determine_dev_size(struct drbd_device *device, enum dds_flags flags, struct
 		return DS_ERROR;
 	}
 
-	/* no wait necessary anymore, actually we could assert that */
-	wait_event(device->al_wait, lc_try_lock(device->act_log));
-
-	prev_first_sect = drbd_md_first_sector(device->ldev);
-	prev_size = device->ldev->md.md_size_sect;
-	la_size_sect = device->ldev->md.la_size_sect;
+	/* remember current offset and sizes */
+	prev.last_agreed_sect = md->la_size_sect;
+	prev.md_offset = md->md_offset;
+	prev.al_offset = md->al_offset;
+	prev.bm_offset = md->bm_offset;
+	prev.md_size_sect = md->md_size_sect;
+	prev.al_stripes = md->al_stripes;
+	prev.al_stripe_size_4k = md->al_stripe_size_4k;
 
 	if (rs) {
 		/* rs is non NULL if we should change the AL layout only */
-
-		prev_al_stripes = md->al_stripes;
-		prev_al_stripe_size_4k = md->al_stripe_size_4k;
-
 		md->al_stripes = rs->al_stripes;
 		md->al_stripe_size_4k = rs->al_stripe_size / 4;
 		md->al_size_4k = (u64)rs->al_stripes * rs->al_stripe_size / 4;
@@ -980,7 +985,7 @@ drbd_determine_dev_size(struct drbd_device *device, enum dds_flags flags, struct
 	rcu_read_unlock();
 	size = drbd_new_dev_size(device, device->ldev, u_size, flags & DDSF_FORCED);
 
-	if (size < la_size_sect) {
+	if (size < prev.last_agreed_sect) {
 		if (rs && u_size == 0) {
 			/* Remove "rs &&" later. This check should always be active, but
 			   right now the receiver expects the permissive behavior */
@@ -1001,30 +1006,29 @@ drbd_determine_dev_size(struct drbd_device *device, enum dds_flags flags, struct
 		err = drbd_bm_resize(device, size, !(flags & DDSF_NO_RESYNC));
 		if (unlikely(err)) {
 			/* currently there is only one error: ENOMEM! */
-			size = drbd_bm_capacity(device)>>1;
+			size = drbd_bm_capacity(device);
 			if (size == 0) {
 				drbd_err(device, "OUT OF MEMORY! "
 				    "Could not allocate bitmap!\n");
 			} else {
 				drbd_err(device, "BM resizing failed. "
-				    "Leaving size unchanged at size = %lu KB\n",
-				    (unsigned long)size);
+				    "Leaving size unchanged\n");
 			}
 			rv = DS_ERROR;
 		}
 		/* racy, see comments above. */
 		drbd_set_my_capacity(device, size);
-		device->ldev->md.la_size_sect = size;
+		md->la_size_sect = size;
 		drbd_info(device, "size = %s (%llu KB)\n", ppsize(ppb, size>>1),
 		     (unsigned long long)size>>1);
 	}
 	if (rv <= DS_ERROR)
 		goto err_out;
 
-	la_size_changed = (la_size_sect != device->ldev->md.la_size_sect);
+	la_size_changed = (prev.last_agreed_sect != md->la_size_sect);
 
-	md_moved = prev_first_sect != drbd_md_first_sector(device->ldev)
-		|| prev_size	   != device->ldev->md.md_size_sect;
+	md_moved = prev.md_offset    != md->md_offset
+		|| prev.md_size_sect != md->md_size_sect;
 
 	if (la_size_changed || md_moved || rs) {
 		u32 prev_flags;
@@ -1033,20 +1037,29 @@ drbd_determine_dev_size(struct drbd_device *device, enum dds_flags flags, struct
 		 * Clear the timer, to avoid scary "timer expired!" messages,
 		 * "Superblock" is written out at least twice below, anyways. */
 		del_timer(&device->md_sync_timer);
-		drbd_al_shrink(device); /* All extents inactive. */
 
+		/* We won't change the "al-extents" setting, we just may need
+		 * to move the on-disk location of the activity log ringbuffer.
+		 * Lock for transaction is good enough, it may well be "dirty"
+		 * or even "starving". */
+		wait_event(device->al_wait, lc_try_lock_for_transaction(device->act_log));
+
+		/* mark current on-disk bitmap and activity log as unreliable */
 		prev_flags = md->flags;
-		md->flags &= ~MDF_PRIMARY_IND;
+		md->flags |= MDF_FULL_SYNC | MDF_AL_DISABLED;
 		drbd_md_write(device, buffer);
 
+		drbd_al_initialize(device, buffer);
+
 		drbd_info(device, "Writing the whole bitmap, %s\n",
 			 la_size_changed && md_moved ? "size changed and md moved" :
 			 la_size_changed ? "size changed" : "md moved");
 		/* next line implicitly does drbd_suspend_io()+drbd_resume_io() */
 		drbd_bitmap_io(device, md_moved ? &drbd_bm_write_all : &drbd_bm_write,
 			       "size changed", BM_LOCKED_MASK);
-		drbd_initialize_al(device, buffer);
 
+		/* on-disk bitmap and activity log is authoritative again
+		 * (unless there was an IO error meanwhile...) */
 		md->flags = prev_flags;
 		drbd_md_write(device, buffer);
 
@@ -1055,20 +1068,22 @@ drbd_determine_dev_size(struct drbd_device *device, enum dds_flags flags, struct
 				  md->al_stripes, md->al_stripe_size_4k * 4);
 	}
 
-	if (size > la_size_sect)
-		rv = la_size_sect ? DS_GREW : DS_GREW_FROM_ZERO;
-	if (size < la_size_sect)
+	if (size > prev.last_agreed_sect)
+		rv = prev.last_agreed_sect ? DS_GREW : DS_GREW_FROM_ZERO;
+	if (size < prev.last_agreed_sect)
 		rv = DS_SHRUNK;
 
 	if (0) {
 	err_out:
-		if (rs) {
-			md->al_stripes = prev_al_stripes;
-			md->al_stripe_size_4k = prev_al_stripe_size_4k;
-			md->al_size_4k = (u64)prev_al_stripes * prev_al_stripe_size_4k;
-
-			drbd_md_set_sector_offsets(device, device->ldev);
-		}
+		/* restore previous offset and sizes */
+		md->la_size_sect = prev.last_agreed_sect;
+		md->md_offset = prev.md_offset;
+		md->al_offset = prev.al_offset;
+		md->bm_offset = prev.bm_offset;
+		md->md_size_sect = prev.md_size_sect;
+		md->al_stripes = prev.al_stripes;
+		md->al_stripe_size_4k = prev.al_stripe_size_4k;
+		md->al_size_4k = (u64)prev.al_stripes * prev.al_stripe_size_4k;
 	}
 	lc_unlock(device->act_log);
 	wake_up(&device->al_wait);
@@ -2764,6 +2779,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 		mutex_unlock(&device->resource->conf_update);
 		synchronize_rcu();
 		kfree(old_disk_conf);
+		new_disk_conf = NULL;
 	}
 
 	ddsf = (rs.resize_force ? DDSF_FORCED : 0) | (rs.no_resync ? DDSF_NO_RESYNC : 0);
@@ -2797,6 +2813,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 
  fail_ldev:
 	put_ldev(device);
+	kfree(new_disk_conf);
 	goto fail;
 }
 
@@ -3216,8 +3233,8 @@ static void device_to_statistics(struct device_statistics *s,
 		q = bdev_get_queue(device->ldev->backing_bdev);
 		s->dev_lower_blocked =
 			bdi_congested(&q->backing_dev_info,
-				      (1 << BDI_async_congested) |
-				      (1 << BDI_sync_congested));
+				      (1 << WB_async_congested) |
+				      (1 << WB_sync_congested));
 		put_ldev(device);
 	}
 	s->dev_size = drbd_get_capacity(device->this_bdev);
diff --git a/drbd/drbd_receiver.c b/drbd/drbd_receiver.c
index 5e6b149..06e5667 100644
--- a/drbd/drbd_receiver.c
+++ b/drbd/drbd_receiver.c
@@ -673,7 +673,7 @@ static struct socket *drbd_try_connect(struct drbd_connection *connection, int u
 		((struct sockaddr_in *)&src_in6)->sin_port = 0; /* AF_INET & AF_SCI */
 
 	what = "sock_create_kern_in_try_connect";
-	err = sock_create_kern(((struct sockaddr *)&src_in6)->sa_family,
+	err = sock_create_kern(&init_net, ((struct sockaddr *)&src_in6)->sa_family,
 			       SOCK_STREAM, IPPROTO_TCP, &sock);
 	if (err < 0) {
 		sock = NULL;
@@ -767,7 +767,7 @@ static struct socket *create_listen_socket(struct drbd_connection *connection,
 	rcu_read_unlock();
 
 	what = "sock_create_kern";
-	err = sock_create_kern(addr->sa_family, SOCK_STREAM, IPPROTO_TCP, &s_listen);
+	err = sock_create_kern(&init_net, addr->sa_family, SOCK_STREAM, IPPROTO_TCP, &s_listen);
 	if (err) {
 		s_listen = NULL;
 		goto out;
@@ -5173,9 +5173,11 @@ static int drbd_disconnected(struct drbd_peer_device *peer_device)
 
 	drbd_md_sync(device);
 
-	/* serialize with bitmap writeout triggered by the state change,
-	 * if any. */
-	wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
+	if (get_ldev(device)) {
+		drbd_bitmap_io(device, &drbd_bm_write_copy_pages,
+				"write from disconnected", BM_LOCKED_CHANGE_ALLOWED);
+		put_ldev(device);
+	}
 
 	/* tcp_close and release of sendpage pages can be deferred.  I don't
 	 * want to use SO_LINGER, because apparently it can be deferred for
diff --git a/drbd/drbd_req.c b/drbd/drbd_req.c
index 38fe40d..305fe71 100644
--- a/drbd/drbd_req.c
+++ b/drbd/drbd_req.c
@@ -31,73 +31,41 @@
 #include "drbd_req.h"
 
 
-/* We only support diskstats for 2.6.16 and up.
- * see also commit commit a362357b6cd62643d4dda3b152639303d78473da
- * Author: Jens Axboe <axboe@suse.de>
- * Date:   Tue Nov 1 09:26:16 2005 +0100
- *     [BLOCK] Unify the separate read/write io stat fields into arrays */
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
-#define _drbd_start_io_acct(...) do {} while (0)
-#define _drbd_end_io_acct(...)   do {} while (0)
-#else
 
 static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size);
 
+#ifndef __disk_stat_inc
 /* Update disk stats at start of I/O request */
 static void _drbd_start_io_acct(struct drbd_device *device, struct drbd_request *req)
 {
-	const int rw = bio_data_dir(req->master_bio);
-#ifndef __disk_stat_inc
-	int cpu;
-#endif
-
-#ifndef COMPAT_HAVE_ATOMIC_IN_FLIGHT
-	spin_lock_irq(&device->resource->req_lock);
-#endif
-
-#ifdef __disk_stat_inc
-	__disk_stat_inc(device->vdisk, ios[rw]);
-	__disk_stat_add(device->vdisk, sectors[rw], req->i.size >> 9);
-	disk_round_stats(device->vdisk);
-	device->vdisk->in_flight++;
-#else
-	cpu = part_stat_lock();
-	part_round_stats(cpu, &device->vdisk->part0);
-	part_stat_inc(cpu, &device->vdisk->part0, ios[rw]);
-	part_stat_add(cpu, &device->vdisk->part0, sectors[rw], req->i.size >> 9);
-	(void) cpu; /* The macro invocations above want the cpu argument, I do not like
-		       the compiler warning about cpu only assigned but never used... */
-	part_inc_in_flight(&device->vdisk->part0, rw);
-	part_stat_unlock();
-#endif
-
-#ifndef COMPAT_HAVE_ATOMIC_IN_FLIGHT
-	spin_unlock_irq(&device->resource->req_lock);
-#endif
+	generic_start_io_acct(bio_data_dir(req->master_bio), req->i.size >> 9,
+			      &device->vdisk->part0);
 }
 
 /* Update disk stats when completing request upwards */
 static void _drbd_end_io_acct(struct drbd_device *device, struct drbd_request *req)
 {
-	int rw = bio_data_dir(req->master_bio);
+	generic_end_io_acct(bio_data_dir(req->master_bio),
+			    &device->vdisk->part0, req->start_jif);
+}
+#else
+static void _drbd_start_io_acct(struct drbd_device *device, struct drbd_request *req)
+{
+	const int rw = bio_data_dir(req->master_bio);
+	BUILD_BUG_ON(sizeof(atomic_t) != sizeof(device->vdisk->in_flight));
+	disk_stat_inc(device->vdisk, ios[rw]);
+	disk_stat_add(device->vdisk, sectors[rw], req->i.size >> 9);
+	disk_round_stats(device->vdisk);
+	atomic_inc((atomic_t*)&device->vdisk->in_flight);
+}
+static void _drbd_end_io_acct(struct drbd_device *device, struct drbd_request *req)
+{
+	const int rw = bio_data_dir(req->master_bio);
 	unsigned long duration = jiffies - req->start_jif;
-#ifndef __disk_stat_inc
-	int cpu;
-#endif
-
-#ifdef __disk_stat_add
-	__disk_stat_add(device->vdisk, ticks[rw], duration);
+	disk_stat_add(device->vdisk, ticks[rw], duration);
 	disk_round_stats(device->vdisk);
-	device->vdisk->in_flight--;
-#else
-	cpu = part_stat_lock();
-	part_stat_add(cpu, &device->vdisk->part0, ticks[rw], duration);
-	part_round_stats(cpu, &device->vdisk->part0);
-	part_dec_in_flight(&device->vdisk->part0, rw);
-	part_stat_unlock();
-#endif
+	atomic_dec((atomic_t*)&device->vdisk->in_flight);
 }
-
 #endif
 
 static struct drbd_request *drbd_req_new(struct drbd_device *device,
@@ -509,7 +477,7 @@ static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
 			atomic_add(req->i.size >> 9, &device->ap_in_flight);
 			set_if_null_req_not_net_done(peer_device, req);
 		}
-		if (s & RQ_NET_PENDING)
+		if (req->rq_state & RQ_NET_PENDING)
 			set_if_null_req_ack_pending(peer_device, req);
 	}
 
@@ -1028,16 +996,20 @@ static void complete_conflicting_writes(struct drbd_request *req)
 	sector_t sector = req->i.sector;
 	int size = req->i.size;
 
-	i = drbd_find_overlap(&device->write_requests, sector, size);
-	if (!i)
-		return;
-
 	for (;;) {
-		prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
-		i = drbd_find_overlap(&device->write_requests, sector, size);
-		if (!i)
+		drbd_for_each_overlap(i, &device->write_requests, sector, size) {
+			/* Ignore, if already completed to upper layers. */
+			if (i->completed)
+				continue;
+			/* Handle the first found overlap.  After the schedule
+			 * we have to restart the tree walk. */
 			break;
+		}
+		if (!i)	/* if any */
+			break;
+
 		/* Indicate to wake up device->misc_wait on progress.  */
+		prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
 		i->waiting = true;
 		spin_unlock_irq(&device->resource->req_lock);
 		schedule();
diff --git a/drbd/drbd_state.c b/drbd/drbd_state.c
index a64cf22..4cf2c93 100644
--- a/drbd/drbd_state.c
+++ b/drbd/drbd_state.c
@@ -1490,7 +1490,7 @@ int drbd_bitmap_io_from_worker(struct drbd_device *device,
 	D_ASSERT(device, current == first_peer_device(device)->connection->worker.task);
 
 	/* open coded non-blocking drbd_suspend_io(device); */
-	set_bit(SUSPEND_IO, &device->flags);
+	atomic_inc(&device->suspend_cnt);
 
 	drbd_bm_lock(device, why, flags);
 	rv = io_fn(device);
@@ -1940,12 +1940,17 @@ static void after_state_ch(struct drbd_device *device, union drbd_state os,
 
 	/* This triggers bitmap writeout of potentially still unwritten pages
 	 * if the resync finished cleanly, or aborted because of peer disk
-	 * failure, or because of connection loss.
+	 * failure, or on transition from resync back to AHEAD/BEHIND.
+	 *
+	 * Connection loss is handled in drbd_disconnected() by the receiver.
+	 *
 	 * For resync aborted because of local disk failure, we cannot do
 	 * any bitmap writeout anymore.
+	 *
 	 * No harm done if some bits change during this phase.
 	 */
-	if (os.conn > C_CONNECTED && ns.conn <= C_CONNECTED && get_ldev(device)) {
+	if ((os.conn > C_CONNECTED && os.conn < C_AHEAD) &&
+	    (ns.conn == C_CONNECTED || ns.conn >= C_AHEAD) && get_ldev(device)) {
 		drbd_queue_bitmap_io(device, &drbd_bm_write_copy_pages, NULL,
 			"write from resync_finished", BM_LOCKED_CHANGE_ALLOWED);
 		put_ldev(device);
diff --git a/drbd/drbd_wrappers.h b/drbd/drbd_wrappers.h
index ea2a1fe..d7a4138 100644
--- a/drbd/drbd_wrappers.h
+++ b/drbd/drbd_wrappers.h
@@ -1421,4 +1421,57 @@ do {								\
 } while (0)
 #endif
 
+#ifndef COMPAT_HAVE_GENERIC_START_IO_ACCT
+#ifndef __disk_stat_inc
+static inline void generic_start_io_acct(int rw, unsigned long sectors,
+					 struct hd_struct *part)
+{
+	int cpu;
+	BUILD_BUG_ON(sizeof(atomic_t) != sizeof(part->in_flight[0]));
+
+	cpu = part_stat_lock();
+	part_round_stats(cpu, part);
+	part_stat_inc(cpu, part, ios[rw]);
+	part_stat_add(cpu, part, sectors[rw], sectors);
+	(void) cpu; /* The macro invocations above want the cpu argument, I do not like
+		       the compiler warning about cpu only assigned but never used... */
+	/* part_inc_in_flight(part, rw); */
+	atomic_inc((atomic_t*)&part->in_flight[rw]);
+	part_stat_unlock();
+}
+
+static inline void generic_end_io_acct(int rw, struct hd_struct *part,
+				  unsigned long start_time)
+{
+	unsigned long duration = jiffies - start_time;
+	int cpu;
+
+	cpu = part_stat_lock();
+	part_stat_add(cpu, part, ticks[rw], duration);
+	part_round_stats(cpu, part);
+	/* part_dec_in_flight(part, rw); */
+	atomic_dec((atomic_t*)&part->in_flight[rw]);
+	part_stat_unlock();
+}
+#endif /* __disk_stat_inc */
+#endif /* COMPAT_HAVE_GENERIC_START_IO_ACCT */
+
+
+#ifndef COMPAT_SOCK_CREATE_KERN_HAS_FIVE_PARAMETERS
+#define sock_create_kern(N,F,T,P,S) sock_create_kern(F,T,P,S)
+#endif
+
+#ifndef COMPAT_HAVE_WB_CONGESTED_ENUM
+#define WB_async_congested BDI_async_congested
+#define WB_sync_congested BDI_sync_congested
+#endif
+
+#ifndef COMPAT_HAVE_SIMPLE_POSITIVE
+#include <linux/dcache.h>
+static inline int simple_positive(struct dentry *dentry)
+{
+        return dentry->d_inode && !d_unhashed(dentry);
+}
+#endif
+
 #endif
diff --git a/drbd/linux/lru_cache.h b/drbd/linux/lru_cache.h
index 98e231c..a1347c5 100644
--- a/drbd/linux/lru_cache.h
+++ b/drbd/linux/lru_cache.h
@@ -300,7 +300,7 @@ extern unsigned int lc_put(struct lru_cache *lc, struct lc_element *e);
 extern void lc_committed(struct lru_cache *lc);
 
 struct seq_file;
-extern size_t lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc);
+extern void lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc);
 
 extern void lc_seq_dump_details(struct seq_file *seq, struct lru_cache *lc, char *utext,
 				void (*detail) (struct seq_file *, struct lc_element *));
diff --git a/drbd/lru_cache.c b/drbd/lru_cache.c
index 76308df..038c986 100644
--- a/drbd/lru_cache.c
+++ b/drbd/lru_cache.c
@@ -233,7 +233,7 @@ void lc_reset(struct lru_cache *lc)
  * @seq: the seq_file to print into
  * @lc: the lru cache to print statistics of
  */
-size_t lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc)
+void lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc)
 {
 	/* NOTE:
 	 * total calls to lc_get are
@@ -242,10 +242,9 @@ size_t lc_seq_printf_stats(struct seq_file *seq, struct lru_cache *lc)
 	 * progress) and "changed", when this in fact lead to an successful
 	 * update of the cache.
 	 */
-	return seq_printf(seq, "\t%s: used:%u/%u "
-		"hits:%lu misses:%lu starving:%lu locked:%lu changed:%lu\n",
-		lc->name, lc->used, lc->nr_elements,
-		lc->hits, lc->misses, lc->starving, lc->locked, lc->changed);
+	seq_printf(seq, "\t%s: used:%u/%u hits:%lu misses:%lu starving:%lu locked:%lu changed:%lu\n",
+		   lc->name, lc->used, lc->nr_elements,
+		   lc->hits, lc->misses, lc->starving, lc->locked, lc->changed);
 }
 
 static struct hlist_head *lc_hash_slot(struct lru_cache *lc, unsigned int enr)
diff --git a/preamble b/preamble
index 603c8ca..a230a24 100644
--- a/preamble
+++ b/preamble
@@ -1,5 +1,5 @@
 # always require a suitable userland
-Requires: drbd-utils = 8.4.5
+Requires: drbd-utils >= 8.9.2
 
 %if %{defined suse_kernel_module_package}
 %if 0%{?sles_version} == 10