[Drbd-dev] [PATCH 00/24] RFC: DRBD Fixes and REQ_DISCARD support

[Drbd-dev] [PATCH 00/24] RFC: DRBD Fixes and REQ_DISCARD support

[Philipp Reisner]

This patch series contains these new features for DRBD:
 * Support for REQ_DISCARD
 * Allow parallel promote/demote
 * Allow online changing of al-stripes and al-stripe-size with the
   resize command

and contains fixes for these issues:
 * fix potential deadlock when concurrently fencing and establishing a connection
 * fix potential distributed deadlock during verify or resync
 * fix decoding of bitmap vli rle for device sizes > 64 TB
 * fix for deadlock when using automatic split-brain-recovery
 * only fail empty flushes if no good data is reachable
 * avoid to shrink max_bio_size due to peer re-configuration
 * fix resume-io after reconnect with broken fence-peer handler
 * fix too large bursts for very slow resync rates
 * don't let application IO throttle resync to a stall
 * Fixed a hole in the challenge-response implementation
 * Fixed a theoretical IO deadlock (Only triggers with unusual small AL i.e. 7)
 * Fixed attaching to disks with fixed size external meta-data
   (This regressions was introduced with 8.4.3)
 * Fixed a crash when the connection broke at a very exact point in
   time while a graceful disconnect executes

Lars Ellenberg (15):
  drbd: fix stalled resync detection in /proc/drbd
  drbd: resync: fix too large bursts for very slow rates
  drbd: fix potential distributed deadlock during verify or resync
  drbd: don't let application IO pre-empt resync too often
  drbd: perpare for genetlink parallel_ops
  drbd: allow parallel promote/demote actions
  drbd: prepare receiving side for REQ_DISCARD
  drbd: prepare sending side for REQ_DISCARD
  drbd: Enable QUEUE_FLAG_DISCARD only if the peer can recieve P_TRIM
  drbd: fix a race between start_resync and send_and_submit
  drbd: keep max-bio size during detach/attach on disconnected primary
  drbd: add back some fairness to AL transactions
  drbd: always implicitly close last epoch when idle
  drbd: evaluate disk and network timeout on different requests
  drbd: use list_first_entry_or_null in first_peer_device/first_connection

Philipp Reisner (9):
  drbd: Break a deadlock while concurrent fencing and establishing a connection
  drbd: Leave IO suspended if the fence handler find the peer primary
  drbd: Remove drbd_wrappers.h
  drbd: Allow online layout change of AL while peer is not connected
  drbd: Do not BUG() when connection breaks in a special way
  drbd: Fix a hole in the challange-response connection authentication
  drbd: use blk_set_stacking_limits()
  drbd: Test cstate while holding req_lock
  drbd: Allow attaching of a newly created device to any backing device

 drivers/block/drbd/drbd_actlog.c   |  23 +-
 drivers/block/drbd/drbd_int.h      |  92 ++++++-
 drivers/block/drbd/drbd_main.c     |  28 ++-
 drivers/block/drbd/drbd_nl.c       | 485 ++++++++++++++++++++++---------------
 drivers/block/drbd/drbd_nla.c      |   1 -
 drivers/block/drbd/drbd_proc.c     |   2 +-
 drivers/block/drbd/drbd_protocol.h |  12 +
 drivers/block/drbd/drbd_receiver.c | 196 ++++++++++-----
 drivers/block/drbd/drbd_req.c      |  74 ++++--
 drivers/block/drbd/drbd_req.h      |   6 +-
 drivers/block/drbd/drbd_state.c    |  38 +--
 drivers/block/drbd/drbd_worker.c   | 107 ++++----
 drivers/block/drbd/drbd_wrappers.h |  54 -----
 13 files changed, 701 insertions(+), 417 deletions(-)
 delete mode 100644 drivers/block/drbd/drbd_wrappers.h

-- 
1.9.1

[Drbd-dev] [PATCH 01/24] drbd: Break a deadlock while concurrent fencing and establishing a connection

[Philipp Reisner]

When we need to outdate the peer while being promoted to primary,
and the connection gets established at the same time, we deadlock
in drbd_try_outdate_peer() when trying to clear the susp_fen
bit.

Fix this by setting the STATE_SENT bit while holding the mutex.

Using drbd_change_state(.. , CS_HARD, ..) which does not block
until STATE_SENT is cleared, is only for clearness. It does
not contribute anything to the fix.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_receiver.c | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 68e3992..125c9e8 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1026,24 +1026,27 @@ randomize:
 	if (drbd_send_protocol(connection) == -EOPNOTSUPP)
 		return -1;
 
+	/* Prevent a race between resync-handshake and
+	 * being promoted to Primary.
+	 *
+	 * Grab and release the state mutex, so we know that any current
+	 * drbd_set_role() is finished, and any incoming drbd_set_role
+	 * will see the STATE_SENT flag, and wait for it to be cleared.
+	 */
+	idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
+		mutex_lock(peer_device->device->state_mutex);
+
 	set_bit(STATE_SENT, &connection->flags);
 
+	idr_for_each_entry(&connection->peer_devices, peer_device, vnr)
+		mutex_unlock(peer_device->device->state_mutex);
+
 	rcu_read_lock();
 	idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
 		struct drbd_device *device = peer_device->device;
 		kref_get(&device->kref);
 		rcu_read_unlock();
 
-		/* Prevent a race between resync-handshake and
-		 * being promoted to Primary.
-		 *
-		 * Grab and release the state mutex, so we know that any current
-		 * drbd_set_role() is finished, and any incoming drbd_set_role
-		 * will see the STATE_SENT flag, and wait for it to be cleared.
-		 */
-		mutex_lock(device->state_mutex);
-		mutex_unlock(device->state_mutex);
-
 		if (discard_my_data)
 			set_bit(DISCARD_MY_DATA, &device->flags);
 		else
-- 
1.9.1

[Drbd-dev] [PATCH 02/24] drbd: Leave IO suspended if the fence handler find the peer primary

[Philipp Reisner]

Actually we are clearing the susp_fen flag if we are not going
to call a fencing handler.

For setting the susp_fen flag needs to be edge-triggerd, and not
level triggered.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_nl.c    |  8 ++++++++
 drivers/block/drbd/drbd_state.c | 24 +++++++++++++-----------
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 526414b..5ccbd71 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -426,6 +426,14 @@ static enum drbd_fencing_p highest_fencing_policy(struct drbd_connection *connec
 	}
 	rcu_read_unlock();
 
+	if (fp == FP_NOT_AVAIL) {
+		/* IO Suspending works on the whole resource.
+		   Do it only for one device. */
+		vnr = 0;
+		peer_device = idr_get_next(&connection->peer_devices, &vnr);
+		drbd_change_state(peer_device->device, CS_VERBOSE | CS_HARD, NS(susp_fen, 0));
+	}
+
 	return fp;
 }
 
diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index 1a84345..3796662 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -54,8 +54,8 @@ static void after_state_ch(struct drbd_device *device, union drbd_state os,
 static enum drbd_state_rv is_valid_state(struct drbd_device *, union drbd_state);
 static enum drbd_state_rv is_valid_soft_transition(union drbd_state, union drbd_state, struct drbd_connection *);
 static enum drbd_state_rv is_valid_transition(union drbd_state os, union drbd_state ns);
-static union drbd_state sanitize_state(struct drbd_device *device, union drbd_state ns,
-				       enum sanitize_state_warnings *warn);
+static union drbd_state sanitize_state(struct drbd_device *device, union drbd_state os,
+				       union drbd_state ns, enum sanitize_state_warnings *warn);
 
 static inline bool is_susp(union drbd_state s)
 {
@@ -287,7 +287,7 @@ _req_st_cond(struct drbd_device *device, union drbd_state mask,
 
 	spin_lock_irqsave(&device->resource->req_lock, flags);
 	os = drbd_read_state(device);
-	ns = sanitize_state(device, apply_mask_val(os, mask, val), NULL);
+	ns = sanitize_state(device, os, apply_mask_val(os, mask, val), NULL);
 	rv = is_valid_transition(os, ns);
 	if (rv >= SS_SUCCESS)
 		rv = SS_UNKNOWN_ERROR;  /* cont waiting, otherwise fail. */
@@ -333,7 +333,7 @@ drbd_req_state(struct drbd_device *device, union drbd_state mask,
 
 	spin_lock_irqsave(&device->resource->req_lock, flags);
 	os = drbd_read_state(device);
-	ns = sanitize_state(device, apply_mask_val(os, mask, val), NULL);
+	ns = sanitize_state(device, os, apply_mask_val(os, mask, val), NULL);
 	rv = is_valid_transition(os, ns);
 	if (rv < SS_SUCCESS) {
 		spin_unlock_irqrestore(&device->resource->req_lock, flags);
@@ -740,8 +740,8 @@ static void print_sanitize_warnings(struct drbd_device *device, enum sanitize_st
  * 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_device *device, union drbd_state ns,
-				       enum sanitize_state_warnings *warn)
+static union drbd_state sanitize_state(struct drbd_device *device, union drbd_state os,
+				       union drbd_state ns, enum sanitize_state_warnings *warn)
 {
 	enum drbd_fencing_p fp;
 	enum drbd_disk_state disk_min, disk_max, pdsk_min, pdsk_max;
@@ -882,11 +882,13 @@ static union drbd_state sanitize_state(struct drbd_device *device, union drbd_st
 	}
 
 	if (fp == FP_STONITH &&
-	    (ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.pdsk > D_OUTDATED))
+	    (ns.role == R_PRIMARY && ns.conn < C_CONNECTED && ns.pdsk > D_OUTDATED) &&
+	    !(os.role == R_PRIMARY && os.conn < C_CONNECTED && os.pdsk > D_OUTDATED))
 		ns.susp_fen = 1; /* Suspend IO while fence-peer handler runs (peer lost) */
 
 	if (device->resource->res_opts.on_no_data == OND_SUSPEND_IO &&
-	    (ns.role == R_PRIMARY && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE))
+	    (ns.role == R_PRIMARY && ns.disk < D_UP_TO_DATE && ns.pdsk < D_UP_TO_DATE) &&
+	    !(os.role == R_PRIMARY && os.disk < D_UP_TO_DATE && os.pdsk < D_UP_TO_DATE))
 		ns.susp_nod = 1; /* Suspend IO while no data available (no accessible data available) */
 
 	if (ns.aftr_isp || ns.peer_isp || ns.user_isp) {
@@ -958,7 +960,7 @@ __drbd_set_state(struct drbd_device *device, union drbd_state ns,
 
 	os = drbd_read_state(device);
 
-	ns = sanitize_state(device, ns, &ssw);
+	ns = sanitize_state(device, os, ns, &ssw);
 	if (ns.i == os.i)
 		return SS_NOTHING_TO_DO;
 
@@ -1656,7 +1658,7 @@ conn_is_valid_transition(struct drbd_connection *connection, union drbd_state ma
 	idr_for_each_entry(&connection->peer_devices, peer_device, vnr) {
 		struct drbd_device *device = peer_device->device;
 		os = drbd_read_state(device);
-		ns = sanitize_state(device, apply_mask_val(os, mask, val), NULL);
+		ns = sanitize_state(device, os, apply_mask_val(os, mask, val), NULL);
 
 		if (flags & CS_IGN_OUTD_FAIL && ns.disk == D_OUTDATED && os.disk < D_OUTDATED)
 			ns.disk = os.disk;
@@ -1718,7 +1720,7 @@ conn_set_state(struct drbd_connection *connection, union drbd_state mask, union
 		number_of_volumes++;
 		os = drbd_read_state(device);
 		ns = apply_mask_val(os, mask, val);
-		ns = sanitize_state(device, ns, NULL);
+		ns = sanitize_state(device, os, ns, NULL);
 
 		if (flags & CS_IGN_OUTD_FAIL && ns.disk == D_OUTDATED && os.disk < D_OUTDATED)
 			ns.disk = os.disk;
-- 
1.9.1

[Drbd-dev] [PATCH 03/24] drbd: Remove drbd_wrappers.h

[Philipp Reisner]

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_actlog.c   |  1 -
 drivers/block/drbd/drbd_int.h      | 35 ++++++++++++++++++++++++
 drivers/block/drbd/drbd_nl.c       |  1 -
 drivers/block/drbd/drbd_nla.c      |  1 -
 drivers/block/drbd/drbd_req.h      |  1 -
 drivers/block/drbd/drbd_wrappers.h | 54 --------------------------------------
 6 files changed, 35 insertions(+), 58 deletions(-)
 delete mode 100644 drivers/block/drbd/drbd_wrappers.h

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 90ae4ba..7e7b0e1 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -29,7 +29,6 @@
 #include <linux/drbd_limits.h>
 #include <linux/dynamic_debug.h>
 #include "drbd_int.h"
-#include "drbd_wrappers.h"
 
 
 enum al_transaction_types {
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index e7093d4..361a2e9 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1283,6 +1283,10 @@ extern void conn_try_outdate_peer_async(struct drbd_connection *connection);
 extern int drbd_khelper(struct drbd_device *device, char *cmd);
 
 /* drbd_worker.c */
+/* bi_end_io handlers */
+extern void drbd_md_io_complete(struct bio *bio, int error);
+extern void drbd_peer_request_endio(struct bio *bio, int error);
+extern void drbd_request_endio(struct bio *bio, int error);
 extern int drbd_worker(struct drbd_thread *thi);
 enum drbd_ret_code drbd_resync_after_valid(struct drbd_device *device, int o_minor);
 void drbd_resync_after_changed(struct drbd_device *device);
@@ -1401,6 +1405,37 @@ static inline void drbd_tcp_quickack(struct socket *sock)
 			(char*)&val, sizeof(val));
 }
 
+/* sets the number of 512 byte sectors of our virtual device */
+static inline void drbd_set_my_capacity(struct drbd_device *device,
+					sector_t size)
+{
+	/* set_capacity(device->this_bdev->bd_disk, size); */
+	set_capacity(device->vdisk, size);
+	device->this_bdev->bd_inode->i_size = (loff_t)size << 9;
+}
+
+/*
+ * used to submit our private bio
+ */
+static inline void drbd_generic_make_request(struct drbd_device *device,
+					     int fault_type, struct bio *bio)
+{
+	__release(local);
+	if (!bio->bi_bdev) {
+		printk(KERN_ERR "drbd%d: drbd_generic_make_request: "
+				"bio->bi_bdev == NULL\n",
+		       device_to_minor(device));
+		dump_stack();
+		bio_endio(bio, -ENODEV);
+		return;
+	}
+
+	if (drbd_insert_fault(device, fault_type))
+		bio_endio(bio, -EIO);
+	else
+		generic_make_request(bio);
+}
+
 void drbd_bump_write_ordering(struct drbd_connection *connection, enum write_ordering_e wo);
 
 /* drbd_proc.c */
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 5ccbd71..e891cb0 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -34,7 +34,6 @@
 #include "drbd_int.h"
 #include "drbd_protocol.h"
 #include "drbd_req.h"
-#include "drbd_wrappers.h"
 #include <asm/unaligned.h>
 #include <linux/drbd_limits.h>
 #include <linux/kthread.h>
diff --git a/drivers/block/drbd/drbd_nla.c b/drivers/block/drbd/drbd_nla.c
index fa672b6d..b2d4791 100644
--- a/drivers/block/drbd/drbd_nla.c
+++ b/drivers/block/drbd/drbd_nla.c
@@ -1,4 +1,3 @@
-#include "drbd_wrappers.h"
 #include <linux/kernel.h>
 #include <net/netlink.h>
 #include <linux/drbd_genl_api.h>
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index c684c96..07cc8e8 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -30,7 +30,6 @@
 #include <linux/slab.h>
 #include <linux/drbd.h>
 #include "drbd_int.h"
-#include "drbd_wrappers.h"
 
 /* The request callbacks will be called in irq context by the IDE drivers,
    and in Softirqs/Tasklets/BH context by the SCSI drivers,
diff --git a/drivers/block/drbd/drbd_wrappers.h b/drivers/block/drbd/drbd_wrappers.h
deleted file mode 100644
index 3db9eba..0000000
--- a/drivers/block/drbd/drbd_wrappers.h
+++ /dev/null
@@ -1,54 +0,0 @@
-#ifndef _DRBD_WRAPPERS_H
-#define _DRBD_WRAPPERS_H
-
-#include <linux/ctype.h>
-#include <linux/mm.h>
-#include "drbd_int.h"
-
-/* see get_sb_bdev and bd_claim */
-extern char *drbd_sec_holder;
-
-/* sets the number of 512 byte sectors of our virtual device */
-static inline void drbd_set_my_capacity(struct drbd_device *device,
-					sector_t size)
-{
-	/* set_capacity(device->this_bdev->bd_disk, size); */
-	set_capacity(device->vdisk, size);
-	device->this_bdev->bd_inode->i_size = (loff_t)size << 9;
-}
-
-#define drbd_bio_uptodate(bio) bio_flagged(bio, BIO_UPTODATE)
-
-/* bi_end_io handlers */
-extern void drbd_md_io_complete(struct bio *bio, int error);
-extern void drbd_peer_request_endio(struct bio *bio, int error);
-extern void drbd_request_endio(struct bio *bio, int error);
-
-/*
- * used to submit our private bio
- */
-static inline void drbd_generic_make_request(struct drbd_device *device,
-					     int fault_type, struct bio *bio)
-{
-	__release(local);
-	if (!bio->bi_bdev) {
-		printk(KERN_ERR "drbd%d: drbd_generic_make_request: "
-				"bio->bi_bdev == NULL\n",
-		       device_to_minor(device));
-		dump_stack();
-		bio_endio(bio, -ENODEV);
-		return;
-	}
-
-	if (drbd_insert_fault(device, fault_type))
-		bio_endio(bio, -EIO);
-	else
-		generic_make_request(bio);
-}
-
-#ifndef __CHECKER__
-# undef __cond_lock
-# define __cond_lock(x,c) (c)
-#endif
-
-#endif
-- 
1.9.1

[Drbd-dev] [PATCH 04/24] drbd: Allow online layout change of AL while peer is not connected

[Philipp Reisner]

If a user forces the operation he takes the blame in case
the peer does not have enough space. No reason to dey this...

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_nl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index e891cb0..d219210 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -2489,7 +2489,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 			goto fail_ldev;
 		}
 
-		if (device->state.conn != C_CONNECTED) {
+		if (device->state.conn != C_CONNECTED && !rs.resize_force) {
 			retcode = ERR_MD_LAYOUT_CONNECTED;
 			goto fail_ldev;
 		}
-- 
1.9.1

[Drbd-dev] [PATCH 05/24] drbd: fix stalled resync detection in /proc/drbd

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

If we don't make resync or verify progress for "too long",
we want to flag it as "stalled".

Since 2010, "use rolling marks for resync speed calculation"
this "too long" was wrong by a factor of HZ.
With HZ 250, it would have been flagged as stalled
after 100 minutes.

Hardcode 3 minutes instead.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index 2f26e8f..89736bd 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -116,7 +116,7 @@ static void drbd_syncer_progress(struct drbd_device *device, struct seq_file *se
 	/* ------------------------ ~18s average ------------------------ */
 	i = (device->rs_last_mark + 2) % DRBD_SYNC_MARKS;
 	dt = (jiffies - device->rs_mark_time[i]) / HZ;
-	if (dt > (DRBD_SYNC_MARK_STEP * DRBD_SYNC_MARKS))
+	if (dt > 180)
 		stalled = 1;
 
 	if (!dt)
-- 
1.9.1

[Drbd-dev] [PATCH 06/24] drbd: resync: fix too large bursts for very slow rates

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

While merging adjacent dirty blocks into resync requests,
the resync rate throttle was disregarded.
For very low resync rates, the effective rate may have exceeded
the intended rate by a larger margin.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_worker.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 2c4ce42..dcd95a6 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -647,7 +647,7 @@ next_sector:
 		 */
 		align = 1;
 		rollback_i = i;
-		for (;;) {
+		while (i < number) {
 			if (size + BM_BLOCK_SIZE > max_bio_size)
 				break;
 
-- 
1.9.1

[Drbd-dev] [PATCH 07/24] drbd: fix potential distributed deadlock during verify or resync

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

If max-buffers and socket buffer sizes are "too small" for the chosen
resync rate, this could lead potentially lead to a distributed deadlock,
which may or may not resolve itself via the "ko-count" and request
timeout mechanism, or could be resolved by forced disconnect.

One option to deal with this is proper configuration:
use larger max-buffer and socket buffers settings,
or reduce the resync rate.

But even with bad configuration we should not deadlock,
but "gracefully" recover.

The issue is avoided by using only up to max-buffers/2 for resync
requests, and by using max-buffers not as a hard limit for data buffer
allocations, but as a throttle threshold only.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_receiver.c | 17 ++++++++++++-----
 drivers/block/drbd/drbd_worker.c   | 27 +++++++++++++++++----------
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 125c9e8..6ffbc22 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -234,9 +234,17 @@ static void drbd_kick_lo_and_reclaim_net(struct drbd_device *device)
  * @retry:	whether to retry, if not enough pages are available right now
  *
  * Tries to allocate number pages, first from our own page pool, then from
- * the kernel, unless this allocation would exceed the max_buffers setting.
+ * the kernel.
  * Possibly retry until DRBD frees sufficient pages somewhere else.
  *
+ * If this allocation would exceed the max_buffers setting, we throttle
+ * allocation (schedule_timeout) to give the system some room to breathe.
+ *
+ * We do not use max-buffers as hard limit, because it could lead to
+ * congestion and further to a distributed deadlock during online-verify or
+ * (checksum based) resync, if the max-buffers, socket buffer sizes and
+ * resync-rate settings are mis-configured.
+ *
  * Returns a page chain linked via page->private.
  */
 struct page *drbd_alloc_pages(struct drbd_peer_device *peer_device, unsigned int number,
@@ -246,10 +254,8 @@ struct page *drbd_alloc_pages(struct drbd_peer_device *peer_device, unsigned int
 	struct page *page = NULL;
 	struct net_conf *nc;
 	DEFINE_WAIT(wait);
-	int mxb;
+	unsigned int mxb;
 
-	/* Yes, we may run up to @number over max_buffers. If we
-	 * follow it strictly, the admin will get it wrong anyways. */
 	rcu_read_lock();
 	nc = rcu_dereference(peer_device->connection->net_conf);
 	mxb = nc ? nc->max_buffers : 1000000;
@@ -277,7 +283,8 @@ struct page *drbd_alloc_pages(struct drbd_peer_device *peer_device, unsigned int
 			break;
 		}
 
-		schedule();
+		if (schedule_timeout(HZ/10) == 0)
+			mxb = UINT_MAX;
 	}
 	finish_wait(&drbd_pp_wait, &wait);
 
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index dcd95a6..7e633ca 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -492,10 +492,9 @@ struct fifo_buffer *fifo_alloc(int fifo_size)
 	return fb;
 }
 
-static int drbd_rs_controller(struct drbd_device *device)
+static int drbd_rs_controller(struct drbd_device *device, unsigned int sect_in)
 {
 	struct disk_conf *dc;
-	unsigned int sect_in;  /* Number of sectors that came in since the last turn */
 	unsigned int want;     /* The number of sectors we want in the proxy */
 	int req_sect; /* Number of sectors to request in this turn */
 	int correction; /* Number of sectors more we need in the proxy*/
@@ -505,9 +504,6 @@ static int drbd_rs_controller(struct drbd_device *device)
 	int max_sect;
 	struct fifo_buffer *plan;
 
-	sect_in = atomic_xchg(&device->rs_sect_in, 0); /* Number of sectors that came in */
-	device->rs_in_flight -= sect_in;
-
 	dc = rcu_dereference(device->ldev->disk_conf);
 	plan = rcu_dereference(device->rs_plan_s);
 
@@ -550,11 +546,16 @@ static int drbd_rs_controller(struct drbd_device *device)
 
 static int drbd_rs_number_requests(struct drbd_device *device)
 {
-	int number;
+	unsigned int sect_in;  /* Number of sectors that came in since the last turn */
+	int number, mxb;
+
+	sect_in = atomic_xchg(&device->rs_sect_in, 0);
+	device->rs_in_flight -= sect_in;
 
 	rcu_read_lock();
+	mxb = drbd_get_max_buffers(device) / 2;
 	if (rcu_dereference(device->rs_plan_s)->size) {
-		number = drbd_rs_controller(device) >> (BM_BLOCK_SHIFT - 9);
+		number = drbd_rs_controller(device, sect_in) >> (BM_BLOCK_SHIFT - 9);
 		device->c_sync_rate = number * HZ * (BM_BLOCK_SIZE / 1024) / SLEEP_TIME;
 	} else {
 		device->c_sync_rate = rcu_dereference(device->ldev->disk_conf)->resync_rate;
@@ -562,8 +563,14 @@ static int drbd_rs_number_requests(struct drbd_device *device)
 	}
 	rcu_read_unlock();
 
-	/* ignore the amount of pending requests, the resync controller should
-	 * throttle down to incoming reply rate soon enough anyways. */
+	/* Don't have more than "max-buffers"/2 in-flight.
+	 * Otherwise we may cause the remote site to stall on drbd_alloc_pages(),
+	 * potentially causing a distributed deadlock on congestion during
+	 * online-verify or (checksum-based) resync, if max-buffers,
+	 * socket buffer sizes and resync rate settings are mis-configured. */
+	if (mxb - device->rs_in_flight < number)
+		number = mxb - device->rs_in_flight;
+
 	return number;
 }
 
@@ -597,7 +604,7 @@ static int make_resync_request(struct drbd_device *device, int cancel)
 
 	max_bio_size = queue_max_hw_sectors(device->rq_queue) << 9;
 	number = drbd_rs_number_requests(device);
-	if (number == 0)
+	if (number <= 0)
 		goto requeue;
 
 	for (i = 0; i < number; i++) {
-- 
1.9.1

[Drbd-dev] [PATCH 08/24] drbd: don't let application IO pre-empt resync too often

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

Before, application IO could pre-empt resync activity
for up to hardcoded 20 seconds per resync request.
A very busy server could throttle the effective resync bandwidth
down to one request per 20 seconds.

Now, we only let application IO pre-empt resync traffic
while the current resync rate estimate is above c-min-rate.

If you disable the c-min-rate throttle feature (set c-min-rate = 0),
application IO will no longer pre-empt resync traffic at all.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_actlog.c   | 13 +++++------
 drivers/block/drbd/drbd_int.h      |  3 ++-
 drivers/block/drbd/drbd_receiver.c | 47 +++++++++++++++++++++-----------------
 3 files changed, 34 insertions(+), 29 deletions(-)

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 7e7b0e1..8dd09a7 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -1022,8 +1022,7 @@ int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
 	unsigned int enr = BM_SECT_TO_EXT(sector);
 	struct bm_extent *bm_ext;
 	int i, sig;
-	int sa = 200; /* Step aside 200 times, then grab the extent and let app-IO wait.
-			 200 times -> 20 seconds. */
+	bool sa;
 
 retry:
 	sig = wait_event_interruptible(device->al_wait,
@@ -1034,12 +1033,15 @@ retry:
 	if (test_bit(BME_LOCKED, &bm_ext->flags))
 		return 0;
 
+	/* step aside only while we are above c-min-rate; unless disabled. */
+	sa = drbd_rs_c_min_rate_throttle(device);
+
 	for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
 		sig = wait_event_interruptible(device->al_wait,
 					       !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) ||
-					       test_bit(BME_PRIORITY, &bm_ext->flags));
+					       (sa && test_bit(BME_PRIORITY, &bm_ext->flags)));
 
-		if (sig || (test_bit(BME_PRIORITY, &bm_ext->flags) && sa)) {
+		if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) {
 			spin_lock_irq(&device->al_lock);
 			if (lc_put(device->resync, &bm_ext->lce) == 0) {
 				bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
@@ -1051,9 +1053,6 @@ retry:
 				return -EINTR;
 			if (schedule_timeout_interruptible(HZ/10))
 				return -EINTR;
-			if (sa && --sa == 0)
-				drbd_warn(device, "drbd_rs_begin_io() stepped aside for 20sec."
-					 "Resync stalled?\n");
 			goto retry;
 		}
 	}
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 361a2e9..f0cabea 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1339,7 +1339,8 @@ extern void start_resync_timer_fn(unsigned long data);
 /* drbd_receiver.c */
 extern int drbd_receiver(struct drbd_thread *thi);
 extern int drbd_asender(struct drbd_thread *thi);
-extern int drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector);
+extern bool drbd_rs_c_min_rate_throttle(struct drbd_device *device);
+extern bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector);
 extern int drbd_submit_peer_request(struct drbd_device *,
 				    struct drbd_peer_request *, const unsigned,
 				    const int);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 6ffbc22..10d2dcb 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2323,39 +2323,45 @@ out_interrupted:
  * The current sync rate used here uses only the most recent two step marks,
  * to have a short time average so we can react faster.
  */
-int drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector)
+bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector)
 {
-	struct gendisk *disk = device->ldev->backing_bdev->bd_contains->bd_disk;
-	unsigned long db, dt, dbdt;
 	struct lc_element *tmp;
-	int curr_events;
-	int throttle = 0;
-	unsigned int c_min_rate;
+	bool throttle = true;
 
-	rcu_read_lock();
-	c_min_rate = rcu_dereference(device->ldev->disk_conf)->c_min_rate;
-	rcu_read_unlock();
-
-	/* feature disabled? */
-	if (c_min_rate == 0)
-		return 0;
+	if (!drbd_rs_c_min_rate_throttle(device))
+		return false;
 
 	spin_lock_irq(&device->al_lock);
 	tmp = lc_find(device->resync, BM_SECT_TO_EXT(sector));
 	if (tmp) {
 		struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
-		if (test_bit(BME_PRIORITY, &bm_ext->flags)) {
-			spin_unlock_irq(&device->al_lock);
-			return 0;
-		}
+		if (test_bit(BME_PRIORITY, &bm_ext->flags))
+			throttle = false;
 		/* Do not slow down if app IO is already waiting for this extent */
 	}
 	spin_unlock_irq(&device->al_lock);
 
+	return throttle;
+}
+
+bool drbd_rs_c_min_rate_throttle(struct drbd_device *device)
+{
+	struct gendisk *disk = device->ldev->backing_bdev->bd_contains->bd_disk;
+	unsigned long db, dt, dbdt;
+	unsigned int c_min_rate;
+	int curr_events;
+
+	rcu_read_lock();
+	c_min_rate = rcu_dereference(device->ldev->disk_conf)->c_min_rate;
+	rcu_read_unlock();
+
+	/* feature disabled? */
+	if (c_min_rate == 0)
+		return false;
+
 	curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
 		      (int)part_stat_read(&disk->part0, sectors[1]) -
 			atomic_read(&device->rs_sect_ev);
-
 	if (!device->rs_last_events || curr_events - device->rs_last_events > 64) {
 		unsigned long rs_left;
 		int i;
@@ -2378,12 +2384,11 @@ int drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector)
 		dbdt = Bit2KB(db/dt);
 
 		if (dbdt > c_min_rate)
-			throttle = 1;
+			return true;
 	}
-	return throttle;
+	return false;
 }
 
-
 static int receive_DataRequest(struct drbd_connection *connection, struct packet_info *pi)
 {
 	struct drbd_peer_device *peer_device;
-- 
1.9.1

[Drbd-dev] [PATCH 09/24] drbd: Do not BUG() when connection breaks in a special way

[Philipp Reisner]

When a 'cluster wide' disconnect executes, the result comes back
from the peer, and immediately after that the connection breaks
then _conn_rq_cond() reported back SS_CW_SUCCESS.
Therefore _conn_request_state() calls conn_set_state(), which
has a BUG() in it.
The BUG() is hit because conn_is_valid_transition() does not like
the transaction. Which goes back to is_valid_soft_transition()
returning SS_OUTDATE_WO_CONN.

This fix is to consider an error reported by is_valid_soft_transition()
even when the peer agreed to the transaction.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_state.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index 3796662..a5d8aae 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -1765,19 +1765,19 @@ conn_set_state(struct drbd_connection *connection, union drbd_state mask, union
 static enum drbd_state_rv
 _conn_rq_cond(struct drbd_connection *connection, union drbd_state mask, union drbd_state val)
 {
-	enum drbd_state_rv rv;
+	enum drbd_state_rv err, rv = SS_UNKNOWN_ERROR; /* continue waiting */;
 
 	if (test_and_clear_bit(CONN_WD_ST_CHG_OKAY, &connection->flags))
-		return SS_CW_SUCCESS;
+		rv = SS_CW_SUCCESS;
 
 	if (test_and_clear_bit(CONN_WD_ST_CHG_FAIL, &connection->flags))
-		return SS_CW_FAILED_BY_PEER;
+		rv = SS_CW_FAILED_BY_PEER;
 
-	rv = conn_is_valid_transition(connection, mask, val, 0);
-	if (rv == SS_SUCCESS && connection->cstate == C_WF_REPORT_PARAMS)
-		rv = SS_UNKNOWN_ERROR; /* continue waiting */
+	err = conn_is_valid_transition(connection, mask, val, 0);
+	if (err == SS_SUCCESS && connection->cstate == C_WF_REPORT_PARAMS)
+		return rv;
 
-	return rv;
+	return err;
 }
 
 enum drbd_state_rv
-- 
1.9.1

[Drbd-dev] [PATCH 10/24] drbd: perpare for genetlink parallel_ops

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

Because all administrative requests via genetlink have been globally
serialized via genl_lock(), we used to have one static struct
drbd_config_context "admin context".

Move this on-stack to the respective callback functions.

This will allow us to selectively drop the genl_lock()
(or use genl_family->parallel_ops) in the future.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_int.h  |  28 +++-
 drivers/block/drbd/drbd_main.c |  12 +-
 drivers/block/drbd/drbd_nl.c   | 333 ++++++++++++++++++++---------------------
 3 files changed, 198 insertions(+), 175 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index f0cabea..20a1772 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -814,6 +814,28 @@ struct drbd_device {
 	struct submit_worker submit;
 };
 
+struct drbd_config_context {
+	/* assigned from drbd_genlmsghdr */
+	unsigned int minor;
+	/* assigned from request attributes, if present */
+	unsigned int volume;
+#define VOLUME_UNSPECIFIED		(-1U)
+	/* pointer into the request skb,
+	 * limited lifetime! */
+	char *resource_name;
+	struct nlattr *my_addr;
+	struct nlattr *peer_addr;
+
+	/* reply buffer */
+	struct sk_buff *reply_skb;
+	/* pointer into reply buffer */
+	struct drbd_genlmsghdr *reply_dh;
+	/* resolved from attributes, if possible */
+	struct drbd_device *device;
+	struct drbd_resource *resource;
+	struct drbd_connection *connection;
+};
+
 static inline struct drbd_device *minor_to_device(unsigned int minor)
 {
 	return (struct drbd_device *)idr_find(&drbd_devices, minor);
@@ -1229,9 +1251,9 @@ extern struct bio *bio_alloc_drbd(gfp_t gfp_mask);
 extern rwlock_t global_state_lock;
 
 extern int conn_lowest_minor(struct drbd_connection *connection);
-enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned int minor, int vnr);
+extern enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor);
 extern void drbd_destroy_device(struct kref *kref);
-extern void drbd_delete_device(struct drbd_device *mdev);
+extern void drbd_delete_device(struct drbd_device *device);
 
 extern struct drbd_resource *drbd_create_resource(const char *name);
 extern void drbd_free_resource(struct drbd_resource *resource);
@@ -1257,7 +1279,7 @@ extern int is_valid_ar_handle(struct drbd_request *, sector_t);
 
 
 /* drbd_nl.c */
-extern int drbd_msg_put_info(const char *info);
+extern int drbd_msg_put_info(struct sk_buff *skb, const char *info);
 extern void drbd_suspend_io(struct drbd_device *device);
 extern void drbd_resume_io(struct drbd_device *device);
 extern char *ppsize(char *buf, unsigned long long size);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 331e5cc..865fdb3 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2687,14 +2687,16 @@ static int init_submitter(struct drbd_device *device)
 	return 0;
 }
 
-enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned int minor, int vnr)
+enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor)
 {
+	struct drbd_resource *resource = adm_ctx->resource;
 	struct drbd_connection *connection;
 	struct drbd_device *device;
 	struct drbd_peer_device *peer_device, *tmp_peer_device;
 	struct gendisk *disk;
 	struct request_queue *q;
 	int id;
+	int vnr = adm_ctx->volume;
 	enum drbd_ret_code err = ERR_NOMEM;
 
 	device = minor_to_device(minor);
@@ -2763,7 +2765,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 	if (id < 0) {
 		if (id == -ENOSPC) {
 			err = ERR_MINOR_EXISTS;
-			drbd_msg_put_info("requested minor exists already");
+			drbd_msg_put_info(adm_ctx->reply_skb, "requested minor exists already");
 		}
 		goto out_no_minor_idr;
 	}
@@ -2773,7 +2775,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 	if (id < 0) {
 		if (id == -ENOSPC) {
 			err = ERR_MINOR_EXISTS;
-			drbd_msg_put_info("requested minor exists already");
+			drbd_msg_put_info(adm_ctx->reply_skb, "requested minor exists already");
 		}
 		goto out_idr_remove_minor;
 	}
@@ -2794,7 +2796,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 		if (id < 0) {
 			if (id == -ENOSPC) {
 				err = ERR_INVALID_REQUEST;
-				drbd_msg_put_info("requested volume exists already");
+				drbd_msg_put_info(adm_ctx->reply_skb, "requested volume exists already");
 			}
 			goto out_idr_remove_from_resource;
 		}
@@ -2803,7 +2805,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_resource *resource, unsigned i
 
 	if (init_submitter(device)) {
 		err = ERR_NOMEM;
-		drbd_msg_put_info("unable to create submit workqueue");
+		drbd_msg_put_info(adm_ctx->reply_skb, "unable to create submit workqueue");
 		goto out_idr_remove_vol;
 	}
 
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index d219210..118ac72 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -81,32 +81,6 @@ int drbd_adm_get_status_all(struct sk_buff *skb, struct netlink_callback *cb);
 /* used blkdev_get_by_path, to claim our meta data device(s) */
 static char *drbd_m_holder = "Hands off! this is DRBD's meta data device.";
 
-/* Configuration is strictly serialized, because generic netlink message
- * processing is strictly serialized by the genl_lock().
- * Which means we can use one static global drbd_config_context struct.
- */
-static struct drbd_config_context {
-	/* assigned from drbd_genlmsghdr */
-	unsigned int minor;
-	/* assigned from request attributes, if present */
-	unsigned int volume;
-#define VOLUME_UNSPECIFIED		(-1U)
-	/* pointer into the request skb,
-	 * limited lifetime! */
-	char *resource_name;
-	struct nlattr *my_addr;
-	struct nlattr *peer_addr;
-
-	/* reply buffer */
-	struct sk_buff *reply_skb;
-	/* pointer into reply buffer */
-	struct drbd_genlmsghdr *reply_dh;
-	/* resolved from attributes, if possible */
-	struct drbd_device *device;
-	struct drbd_resource *resource;
-	struct drbd_connection *connection;
-} adm_ctx;
-
 static void drbd_adm_send_reply(struct sk_buff *skb, struct genl_info *info)
 {
 	genlmsg_end(skb, genlmsg_data(nlmsg_data(nlmsg_hdr(skb))));
@@ -116,9 +90,8 @@ static void drbd_adm_send_reply(struct sk_buff *skb, struct genl_info *info)
 
 /* Used on a fresh "drbd_adm_prepare"d reply_skb, this cannot fail: The only
  * reason it could fail was no space in skb, and there are 4k available. */
-int drbd_msg_put_info(const char *info)
+int drbd_msg_put_info(struct sk_buff *skb, const char *info)
 {
-	struct sk_buff *skb = adm_ctx.reply_skb;
 	struct nlattr *nla;
 	int err = -EMSGSIZE;
 
@@ -146,38 +119,38 @@ int drbd_msg_put_info(const char *info)
 #define DRBD_ADM_NEED_MINOR	1
 #define DRBD_ADM_NEED_RESOURCE	2
 #define DRBD_ADM_NEED_CONNECTION 4
-static int drbd_adm_prepare(struct sk_buff *skb, struct genl_info *info,
-		unsigned flags)
+static int drbd_adm_prepare(struct drbd_config_context *adm_ctx,
+	struct sk_buff *skb, struct genl_info *info, unsigned flags)
 {
 	struct drbd_genlmsghdr *d_in = info->userhdr;
 	const u8 cmd = info->genlhdr->cmd;
 	int err;
 
-	memset(&adm_ctx, 0, sizeof(adm_ctx));
+	memset(adm_ctx, 0, sizeof(*adm_ctx));
 
 	/* genl_rcv_msg only checks for CAP_NET_ADMIN on "GENL_ADMIN_PERM" :( */
 	if (cmd != DRBD_ADM_GET_STATUS && !capable(CAP_NET_ADMIN))
 	       return -EPERM;
 
-	adm_ctx.reply_skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
-	if (!adm_ctx.reply_skb) {
+	adm_ctx->reply_skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+	if (!adm_ctx->reply_skb) {
 		err = -ENOMEM;
 		goto fail;
 	}
 
-	adm_ctx.reply_dh = genlmsg_put_reply(adm_ctx.reply_skb,
+	adm_ctx->reply_dh = genlmsg_put_reply(adm_ctx->reply_skb,
 					info, &drbd_genl_family, 0, cmd);
 	/* put of a few bytes into a fresh skb of >= 4k will always succeed.
 	 * but anyways */
-	if (!adm_ctx.reply_dh) {
+	if (!adm_ctx->reply_dh) {
 		err = -ENOMEM;
 		goto fail;
 	}
 
-	adm_ctx.reply_dh->minor = d_in->minor;
-	adm_ctx.reply_dh->ret_code = NO_ERROR;
+	adm_ctx->reply_dh->minor = d_in->minor;
+	adm_ctx->reply_dh->ret_code = NO_ERROR;
 
-	adm_ctx.volume = VOLUME_UNSPECIFIED;
+	adm_ctx->volume = VOLUME_UNSPECIFIED;
 	if (info->attrs[DRBD_NLA_CFG_CONTEXT]) {
 		struct nlattr *nla;
 		/* parse and validate only */
@@ -187,7 +160,7 @@ static int drbd_adm_prepare(struct sk_buff *skb, struct genl_info *info,
 
 		/* It was present, and valid,
 		 * copy it over to the reply skb. */
-		err = nla_put_nohdr(adm_ctx.reply_skb,
+		err = nla_put_nohdr(adm_ctx->reply_skb,
 				info->attrs[DRBD_NLA_CFG_CONTEXT]->nla_len,
 				info->attrs[DRBD_NLA_CFG_CONTEXT]);
 		if (err)
@@ -196,102 +169,103 @@ static int drbd_adm_prepare(struct sk_buff *skb, struct genl_info *info,
 		/* and assign stuff to the global adm_ctx */
 		nla = nested_attr_tb[__nla_type(T_ctx_volume)];
 		if (nla)
-			adm_ctx.volume = nla_get_u32(nla);
+			adm_ctx->volume = nla_get_u32(nla);
 		nla = nested_attr_tb[__nla_type(T_ctx_resource_name)];
 		if (nla)
-			adm_ctx.resource_name = nla_data(nla);
-		adm_ctx.my_addr = nested_attr_tb[__nla_type(T_ctx_my_addr)];
-		adm_ctx.peer_addr = nested_attr_tb[__nla_type(T_ctx_peer_addr)];
-		if ((adm_ctx.my_addr &&
-		     nla_len(adm_ctx.my_addr) > sizeof(adm_ctx.connection->my_addr)) ||
-		    (adm_ctx.peer_addr &&
-		     nla_len(adm_ctx.peer_addr) > sizeof(adm_ctx.connection->peer_addr))) {
+			adm_ctx->resource_name = nla_data(nla);
+		adm_ctx->my_addr = nested_attr_tb[__nla_type(T_ctx_my_addr)];
+		adm_ctx->peer_addr = nested_attr_tb[__nla_type(T_ctx_peer_addr)];
+		if ((adm_ctx->my_addr &&
+		     nla_len(adm_ctx->my_addr) > sizeof(adm_ctx->connection->my_addr)) ||
+		    (adm_ctx->peer_addr &&
+		     nla_len(adm_ctx->peer_addr) > sizeof(adm_ctx->connection->peer_addr))) {
 			err = -EINVAL;
 			goto fail;
 		}
 	}
 
-	adm_ctx.minor = d_in->minor;
-	adm_ctx.device = minor_to_device(d_in->minor);
-	if (adm_ctx.resource_name) {
-		adm_ctx.resource = drbd_find_resource(adm_ctx.resource_name);
+	adm_ctx->minor = d_in->minor;
+	adm_ctx->device = minor_to_device(d_in->minor);
+	if (adm_ctx->resource_name) {
+		adm_ctx->resource = drbd_find_resource(adm_ctx->resource_name);
 	}
 
-	if (!adm_ctx.device && (flags & DRBD_ADM_NEED_MINOR)) {
-		drbd_msg_put_info("unknown minor");
+	if (!adm_ctx->device && (flags & DRBD_ADM_NEED_MINOR)) {
+		drbd_msg_put_info(adm_ctx->reply_skb, "unknown minor");
 		return ERR_MINOR_INVALID;
 	}
-	if (!adm_ctx.resource && (flags & DRBD_ADM_NEED_RESOURCE)) {
-		drbd_msg_put_info("unknown resource");
-		if (adm_ctx.resource_name)
+	if (!adm_ctx->resource && (flags & DRBD_ADM_NEED_RESOURCE)) {
+		drbd_msg_put_info(adm_ctx->reply_skb, "unknown resource");
+		if (adm_ctx->resource_name)
 			return ERR_RES_NOT_KNOWN;
 		return ERR_INVALID_REQUEST;
 	}
 
 	if (flags & DRBD_ADM_NEED_CONNECTION) {
-		if (adm_ctx.resource) {
-			drbd_msg_put_info("no resource name expected");
+		if (adm_ctx->resource) {
+			drbd_msg_put_info(adm_ctx->reply_skb, "no resource name expected");
 			return ERR_INVALID_REQUEST;
 		}
-		if (adm_ctx.device) {
-			drbd_msg_put_info("no minor number expected");
+		if (adm_ctx->device) {
+			drbd_msg_put_info(adm_ctx->reply_skb, "no minor number expected");
 			return ERR_INVALID_REQUEST;
 		}
-		if (adm_ctx.my_addr && adm_ctx.peer_addr)
-			adm_ctx.connection = conn_get_by_addrs(nla_data(adm_ctx.my_addr),
-							  nla_len(adm_ctx.my_addr),
-							  nla_data(adm_ctx.peer_addr),
-							  nla_len(adm_ctx.peer_addr));
-		if (!adm_ctx.connection) {
-			drbd_msg_put_info("unknown connection");
+		if (adm_ctx->my_addr && adm_ctx->peer_addr)
+			adm_ctx->connection = conn_get_by_addrs(nla_data(adm_ctx->my_addr),
+							  nla_len(adm_ctx->my_addr),
+							  nla_data(adm_ctx->peer_addr),
+							  nla_len(adm_ctx->peer_addr));
+		if (!adm_ctx->connection) {
+			drbd_msg_put_info(adm_ctx->reply_skb, "unknown connection");
 			return ERR_INVALID_REQUEST;
 		}
 	}
 
 	/* some more paranoia, if the request was over-determined */
-	if (adm_ctx.device && adm_ctx.resource &&
-	    adm_ctx.device->resource != adm_ctx.resource) {
+	if (adm_ctx->device && adm_ctx->resource &&
+	    adm_ctx->device->resource != adm_ctx->resource) {
 		pr_warning("request: minor=%u, resource=%s; but that minor belongs to resource %s\n",
-				adm_ctx.minor, adm_ctx.resource->name,
-				adm_ctx.device->resource->name);
-		drbd_msg_put_info("minor exists in different resource");
+				adm_ctx->minor, adm_ctx->resource->name,
+				adm_ctx->device->resource->name);
+		drbd_msg_put_info(adm_ctx->reply_skb, "minor exists in different resource");
 		return ERR_INVALID_REQUEST;
 	}
-	if (adm_ctx.device &&
-	    adm_ctx.volume != VOLUME_UNSPECIFIED &&
-	    adm_ctx.volume != adm_ctx.device->vnr) {
+	if (adm_ctx->device &&
+	    adm_ctx->volume != VOLUME_UNSPECIFIED &&
+	    adm_ctx->volume != adm_ctx->device->vnr) {
 		pr_warning("request: minor=%u, volume=%u; but that minor is volume %u in %s\n",
-				adm_ctx.minor, adm_ctx.volume,
-				adm_ctx.device->vnr,
-				adm_ctx.device->resource->name);
-		drbd_msg_put_info("minor exists as different volume");
+				adm_ctx->minor, adm_ctx->volume,
+				adm_ctx->device->vnr,
+				adm_ctx->device->resource->name);
+		drbd_msg_put_info(adm_ctx->reply_skb, "minor exists as different volume");
 		return ERR_INVALID_REQUEST;
 	}
 
 	return NO_ERROR;
 
 fail:
-	nlmsg_free(adm_ctx.reply_skb);
-	adm_ctx.reply_skb = NULL;
+	nlmsg_free(adm_ctx->reply_skb);
+	adm_ctx->reply_skb = NULL;
 	return err;
 }
 
-static int drbd_adm_finish(struct genl_info *info, int retcode)
+static int drbd_adm_finish(struct drbd_config_context *adm_ctx,
+	struct genl_info *info, int retcode)
 {
-	if (adm_ctx.connection) {
-		kref_put(&adm_ctx.connection->kref, drbd_destroy_connection);
-		adm_ctx.connection = NULL;
+	if (adm_ctx->connection) {
+		kref_put(&adm_ctx->connection->kref, &drbd_destroy_connection);
+		adm_ctx->connection = NULL;
 	}
-	if (adm_ctx.resource) {
-		kref_put(&adm_ctx.resource->kref, drbd_destroy_resource);
-		adm_ctx.resource = NULL;
+	if (adm_ctx->resource) {
+		kref_put(&adm_ctx->resource->kref, drbd_destroy_resource);
+		adm_ctx->resource = NULL;
 	}
 
-	if (!adm_ctx.reply_skb)
+	if (!adm_ctx->reply_skb)
 		return -ENOMEM;
 
-	adm_ctx.reply_dh->ret_code = retcode;
-	drbd_adm_send_reply(adm_ctx.reply_skb, info);
+	adm_ctx->reply_dh->ret_code = retcode;
+	drbd_adm_send_reply(adm_ctx->reply_skb, info);
 	return 0;
 }
 
@@ -707,11 +681,12 @@ static const char *from_attrs_err_to_txt(int err)
 
 int drbd_adm_set_role(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct set_role_parms parms;
 	int err;
 	enum drbd_ret_code retcode;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -722,7 +697,7 @@ int drbd_adm_set_role(struct sk_buff *skb, struct genl_info *info)
 		err = set_role_parms_from_attrs(&parms, info);
 		if (err) {
 			retcode = ERR_MANDATORY_TAG;
-			drbd_msg_put_info(from_attrs_err_to_txt(err));
+			drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 			goto out;
 		}
 	}
@@ -732,7 +707,7 @@ int drbd_adm_set_role(struct sk_buff *skb, struct genl_info *info)
 	else
 		retcode = drbd_set_role(adm_ctx.device, R_SECONDARY, 0);
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -1265,13 +1240,14 @@ static unsigned int drbd_al_extents_max(struct drbd_backing_dev *bdev)
 
 int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	struct drbd_device *device;
 	struct disk_conf *new_disk_conf, *old_disk_conf;
 	struct fifo_buffer *old_plan = NULL, *new_plan = NULL;
 	int err, fifo_size;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -1301,7 +1277,7 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 	err = disk_conf_from_attrs_for_change(new_disk_conf, info);
 	if (err && err != -ENOMSG) {
 		retcode = ERR_MANDATORY_TAG;
-		drbd_msg_put_info(from_attrs_err_to_txt(err));
+		drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 		goto fail_unlock;
 	}
 
@@ -1392,12 +1368,13 @@ fail_unlock:
 success:
 	put_ldev(device);
  out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_device *device;
 	int err;
 	enum drbd_ret_code retcode;
@@ -1413,7 +1390,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 	enum drbd_state_rv rv;
 	struct net_conf *nc;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -1462,7 +1439,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 	err = disk_conf_from_attrs(new_disk_conf, info);
 	if (err) {
 		retcode = ERR_MANDATORY_TAG;
-		drbd_msg_put_info(from_attrs_err_to_txt(err));
+		drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 		goto fail;
 	}
 
@@ -1804,7 +1781,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 	kobject_uevent(&disk_to_dev(device->vdisk)->kobj, KOBJ_CHANGE);
 	put_ldev(device);
 	conn_reconfig_done(first_peer_device(device)->connection);
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 
  force_diskless_dec:
@@ -1828,7 +1805,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 	kfree(new_plan);
 
  finish:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -1867,11 +1844,12 @@ out:
  * Only then we have finally detached. */
 int drbd_adm_detach(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	struct detach_parms parms = { };
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -1881,14 +1859,14 @@ int drbd_adm_detach(struct sk_buff *skb, struct genl_info *info)
 		err = detach_parms_from_attrs(&parms, info);
 		if (err) {
 			retcode = ERR_MANDATORY_TAG;
-			drbd_msg_put_info(from_attrs_err_to_txt(err));
+			drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 			goto out;
 		}
 	}
 
 	retcode = adm_detach(adm_ctx.device, parms.force_detach);
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -2062,6 +2040,7 @@ static void free_crypto(struct crypto *crypto)
 
 int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	struct drbd_connection *connection;
 	struct net_conf *old_net_conf, *new_net_conf = NULL;
@@ -2070,7 +2049,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 	int rsr; /* re-sync running */
 	struct crypto crypto = { };
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_CONNECTION);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_CONNECTION);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2091,7 +2070,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 	old_net_conf = connection->net_conf;
 
 	if (!old_net_conf) {
-		drbd_msg_put_info("net conf missing, try connect");
+		drbd_msg_put_info(adm_ctx.reply_skb, "net conf missing, try connect");
 		retcode = ERR_INVALID_REQUEST;
 		goto fail;
 	}
@@ -2103,7 +2082,7 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 	err = net_conf_from_attrs_for_change(new_net_conf, info);
 	if (err && err != -ENOMSG) {
 		retcode = ERR_MANDATORY_TAG;
-		drbd_msg_put_info(from_attrs_err_to_txt(err));
+		drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 		goto fail;
 	}
 
@@ -2174,12 +2153,13 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
  done:
 	conn_reconfig_done(connection);
  out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_peer_device *peer_device;
 	struct net_conf *old_net_conf, *new_net_conf = NULL;
 	struct crypto crypto = { };
@@ -2189,14 +2169,14 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 	int i;
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_RESOURCE);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
 
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
 		goto out;
 	if (!(adm_ctx.my_addr && adm_ctx.peer_addr)) {
-		drbd_msg_put_info("connection endpoint(s) missing");
+		drbd_msg_put_info(adm_ctx.reply_skb, "connection endpoint(s) missing");
 		retcode = ERR_INVALID_REQUEST;
 		goto out;
 	}
@@ -2242,7 +2222,7 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 	err = net_conf_from_attrs(new_net_conf, info);
 	if (err && err != -ENOMSG) {
 		retcode = ERR_MANDATORY_TAG;
-		drbd_msg_put_info(from_attrs_err_to_txt(err));
+		drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 		goto fail;
 	}
 
@@ -2291,7 +2271,7 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 	retcode = conn_request_state(connection, NS(conn, C_UNCONNECTED), CS_VERBOSE);
 
 	conn_reconfig_done(connection);
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 
 fail:
@@ -2300,7 +2280,7 @@ fail:
 
 	conn_reconfig_done(connection);
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -2363,13 +2343,14 @@ static enum drbd_state_rv conn_try_disconnect(struct drbd_connection *connection
 
 int drbd_adm_disconnect(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct disconnect_parms parms;
 	struct drbd_connection *connection;
 	enum drbd_state_rv rv;
 	enum drbd_ret_code retcode;
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_CONNECTION);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_CONNECTION);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2381,7 +2362,7 @@ int drbd_adm_disconnect(struct sk_buff *skb, struct genl_info *info)
 		err = disconnect_parms_from_attrs(&parms, info);
 		if (err) {
 			retcode = ERR_MANDATORY_TAG;
-			drbd_msg_put_info(from_attrs_err_to_txt(err));
+			drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 			goto fail;
 		}
 	}
@@ -2392,7 +2373,7 @@ int drbd_adm_disconnect(struct sk_buff *skb, struct genl_info *info)
 	else
 		retcode = NO_ERROR;
  fail:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -2414,6 +2395,7 @@ void resync_after_online_grow(struct drbd_device *device)
 
 int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct disk_conf *old_disk_conf, *new_disk_conf = NULL;
 	struct resize_parms rs;
 	struct drbd_device *device;
@@ -2424,7 +2406,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 	sector_t u_size;
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2443,7 +2425,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 		err = resize_parms_from_attrs(&rs, info);
 		if (err) {
 			retcode = ERR_MANDATORY_TAG;
-			drbd_msg_put_info(from_attrs_err_to_txt(err));
+			drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 			goto fail_ldev;
 		}
 	}
@@ -2535,7 +2517,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 	}
 
  fail:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 
  fail_ldev:
@@ -2545,11 +2527,12 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 
 int drbd_adm_resource_opts(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	struct res_opts res_opts;
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_RESOURCE);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2562,7 +2545,7 @@ int drbd_adm_resource_opts(struct sk_buff *skb, struct genl_info *info)
 	err = res_opts_from_attrs(&res_opts, info);
 	if (err && err != -ENOMSG) {
 		retcode = ERR_MANDATORY_TAG;
-		drbd_msg_put_info(from_attrs_err_to_txt(err));
+		drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 		goto fail;
 	}
 
@@ -2574,16 +2557,17 @@ int drbd_adm_resource_opts(struct sk_buff *skb, struct genl_info *info)
 	}
 
 fail:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_device *device;
 	int retcode; /* enum drbd_ret_code rsp. enum drbd_state_rv */
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2614,16 +2598,17 @@ int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info)
 	drbd_resume_io(device);
 
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 static int drbd_adm_simple_request_state(struct sk_buff *skb, struct genl_info *info,
 		union drbd_state mask, union drbd_state val)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2631,7 +2616,7 @@ static int drbd_adm_simple_request_state(struct sk_buff *skb, struct genl_info *
 
 	retcode = drbd_request_state(adm_ctx.device, mask, val);
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -2646,10 +2631,11 @@ static int drbd_bmio_set_susp_al(struct drbd_device *device)
 
 int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	int retcode; /* drbd_ret_code, drbd_state_rv */
 	struct drbd_device *device;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2683,15 +2669,16 @@ int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info)
 	drbd_resume_io(device);
 
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_pause_sync(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2700,16 +2687,17 @@ int drbd_adm_pause_sync(struct sk_buff *skb, struct genl_info *info)
 	if (drbd_request_state(adm_ctx.device, NS(user_isp, 1)) == SS_NOTHING_TO_DO)
 		retcode = ERR_PAUSE_IS_SET;
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_resume_sync(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	union drbd_dev_state s;
 	enum drbd_ret_code retcode;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2726,7 +2714,7 @@ int drbd_adm_resume_sync(struct sk_buff *skb, struct genl_info *info)
 	}
 
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -2737,10 +2725,11 @@ int drbd_adm_suspend_io(struct sk_buff *skb, struct genl_info *info)
 
 int drbd_adm_resume_io(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_device *device;
 	int retcode; /* enum drbd_ret_code rsp. enum drbd_state_rv */
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2762,7 +2751,7 @@ int drbd_adm_resume_io(struct sk_buff *skb, struct genl_info *info)
 	drbd_resume_io(device);
 
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -2938,10 +2927,11 @@ nla_put_failure:
 
 int drbd_adm_get_status(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -2953,7 +2943,7 @@ int drbd_adm_get_status(struct sk_buff *skb, struct genl_info *info)
 		return err;
 	}
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -3140,11 +3130,12 @@ dump:
 
 int drbd_adm_get_timeout_type(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	struct timeout_parms tp;
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -3161,17 +3152,18 @@ int drbd_adm_get_timeout_type(struct sk_buff *skb, struct genl_info *info)
 		return err;
 	}
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_start_ov(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_device *device;
 	enum drbd_ret_code retcode;
 	struct start_ov_parms parms;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -3186,7 +3178,7 @@ int drbd_adm_start_ov(struct sk_buff *skb, struct genl_info *info)
 		int err = start_ov_parms_from_attrs(&parms, info);
 		if (err) {
 			retcode = ERR_MANDATORY_TAG;
-			drbd_msg_put_info(from_attrs_err_to_txt(err));
+			drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 			goto out;
 		}
 	}
@@ -3201,20 +3193,21 @@ int drbd_adm_start_ov(struct sk_buff *skb, struct genl_info *info)
 	retcode = drbd_request_state(device, NS(conn, C_VERIFY_S));
 	drbd_resume_io(device);
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 
 int drbd_adm_new_c_uuid(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_device *device;
 	enum drbd_ret_code retcode;
 	int skip_initial_sync = 0;
 	int err;
 	struct new_c_uuid_parms args;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -3226,7 +3219,7 @@ int drbd_adm_new_c_uuid(struct sk_buff *skb, struct genl_info *info)
 		err = new_c_uuid_parms_from_attrs(&args, info);
 		if (err) {
 			retcode = ERR_MANDATORY_TAG;
-			drbd_msg_put_info(from_attrs_err_to_txt(err));
+			drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 			goto out_nolock;
 		}
 	}
@@ -3276,21 +3269,22 @@ out_dec:
 out:
 	mutex_unlock(device->state_mutex);
 out_nolock:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 static enum drbd_ret_code
-drbd_check_resource_name(const char *name)
+drbd_check_resource_name(struct drbd_config_context *adm_ctx)
 {
+	const char *name = adm_ctx->resource_name;
 	if (!name || !name[0]) {
-		drbd_msg_put_info("resource name missing");
+		drbd_msg_put_info(adm_ctx->reply_skb, "resource name missing");
 		return ERR_MANDATORY_TAG;
 	}
 	/* if we want to use these in sysfs/configfs/debugfs some day,
 	 * we must not allow slashes */
 	if (strchr(name, '/')) {
-		drbd_msg_put_info("invalid resource name");
+		drbd_msg_put_info(adm_ctx->reply_skb, "invalid resource name");
 		return ERR_INVALID_REQUEST;
 	}
 	return NO_ERROR;
@@ -3298,11 +3292,12 @@ drbd_check_resource_name(const char *name)
 
 int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 	struct res_opts res_opts;
 	int err;
 
-	retcode = drbd_adm_prepare(skb, info, 0);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, 0);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -3312,18 +3307,18 @@ int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info)
 	err = res_opts_from_attrs(&res_opts, info);
 	if (err && err != -ENOMSG) {
 		retcode = ERR_MANDATORY_TAG;
-		drbd_msg_put_info(from_attrs_err_to_txt(err));
+		drbd_msg_put_info(adm_ctx.reply_skb, from_attrs_err_to_txt(err));
 		goto out;
 	}
 
-	retcode = drbd_check_resource_name(adm_ctx.resource_name);
+	retcode = drbd_check_resource_name(&adm_ctx);
 	if (retcode != NO_ERROR)
 		goto out;
 
 	if (adm_ctx.resource) {
 		if (info->nlhdr->nlmsg_flags & NLM_F_EXCL) {
 			retcode = ERR_INVALID_REQUEST;
-			drbd_msg_put_info("resource exists");
+			drbd_msg_put_info(adm_ctx.reply_skb, "resource exists");
 		}
 		/* else: still NO_ERROR */
 		goto out;
@@ -3332,28 +3327,29 @@ int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info)
 	if (!conn_create(adm_ctx.resource_name, &res_opts))
 		retcode = ERR_NOMEM;
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_new_minor(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_genlmsghdr *dh = info->userhdr;
 	enum drbd_ret_code retcode;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_RESOURCE);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
 		goto out;
 
 	if (dh->minor > MINORMASK) {
-		drbd_msg_put_info("requested minor out of range");
+		drbd_msg_put_info(adm_ctx.reply_skb, "requested minor out of range");
 		retcode = ERR_INVALID_REQUEST;
 		goto out;
 	}
 	if (adm_ctx.volume > DRBD_VOLUME_MAX) {
-		drbd_msg_put_info("requested volume id out of range");
+		drbd_msg_put_info(adm_ctx.reply_skb, "requested volume id out of range");
 		retcode = ERR_INVALID_REQUEST;
 		goto out;
 	}
@@ -3367,9 +3363,9 @@ int drbd_adm_new_minor(struct sk_buff *skb, struct genl_info *info)
 		goto out;
 	}
 
-	retcode = drbd_create_device(adm_ctx.resource, dh->minor, adm_ctx.volume);
+	retcode = drbd_create_device(&adm_ctx, dh->minor);
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
@@ -3390,9 +3386,10 @@ static enum drbd_ret_code adm_del_minor(struct drbd_device *device)
 
 int drbd_adm_del_minor(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	enum drbd_ret_code retcode;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_MINOR);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_MINOR);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -3400,19 +3397,20 @@ int drbd_adm_del_minor(struct sk_buff *skb, struct genl_info *info)
 
 	retcode = adm_del_minor(adm_ctx.device);
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_resource *resource;
 	struct drbd_connection *connection;
 	struct drbd_device *device;
 	int retcode; /* enum drbd_ret_code rsp. enum drbd_state_rv */
 	unsigned i;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_RESOURCE);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -3426,14 +3424,14 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 		idr_for_each_entry(&connection->peer_devices, peer_device, i) {
 			retcode = drbd_set_role(peer_device->device, R_SECONDARY, 0);
 			if (retcode < SS_SUCCESS) {
-				drbd_msg_put_info("failed to demote");
+				drbd_msg_put_info(adm_ctx.reply_skb, "failed to demote");
 				goto out;
 			}
 		}
 
 		retcode = conn_try_disconnect(connection, 0);
 		if (retcode < SS_SUCCESS) {
-			drbd_msg_put_info("failed to disconnect");
+			drbd_msg_put_info(adm_ctx.reply_skb, "failed to disconnect");
 			goto out;
 		}
 	}
@@ -3442,7 +3440,7 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 	idr_for_each_entry(&resource->devices, device, i) {
 		retcode = adm_detach(device, 0);
 		if (retcode < SS_SUCCESS || retcode > NO_ERROR) {
-			drbd_msg_put_info("failed to detach");
+			drbd_msg_put_info(adm_ctx.reply_skb, "failed to detach");
 			goto out;
 		}
 	}
@@ -3460,7 +3458,7 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 		retcode = adm_del_minor(device);
 		if (retcode != NO_ERROR) {
 			/* "can not happen" */
-			drbd_msg_put_info("failed to delete volume");
+			drbd_msg_put_info(adm_ctx.reply_skb, "failed to delete volume");
 			goto out;
 		}
 	}
@@ -3471,17 +3469,18 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 	retcode = NO_ERROR;
 
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
 int drbd_adm_del_resource(struct sk_buff *skb, struct genl_info *info)
 {
+	struct drbd_config_context adm_ctx;
 	struct drbd_resource *resource;
 	struct drbd_connection *connection;
 	enum drbd_ret_code retcode;
 
-	retcode = drbd_adm_prepare(skb, info, DRBD_ADM_NEED_RESOURCE);
+	retcode = drbd_adm_prepare(&adm_ctx, skb, info, DRBD_ADM_NEED_RESOURCE);
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
@@ -3506,7 +3505,7 @@ int drbd_adm_del_resource(struct sk_buff *skb, struct genl_info *info)
 	drbd_free_resource(resource);
 	retcode = NO_ERROR;
 out:
-	drbd_adm_finish(info, retcode);
+	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
 
-- 
1.9.1

[Drbd-dev] [PATCH 11/24] drbd: allow parallel promote/demote actions

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

We plan to use genl_family->parallel_ops = true in the future,
but need to review all possible interactions first.

For now, only selectively drop genl_lock() in drbd_set_role(),
instead serializing on our own internal resource->conf_update mutex.

We now can be promoted/demoted on many resources in parallel,
which may significantly improve cluster failover times
when fencing is required.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_int.h  |   1 +
 drivers/block/drbd/drbd_main.c |   1 +
 drivers/block/drbd/drbd_nl.c   | 100 +++++++++++++++++++++++++++++++++++------
 3 files changed, 88 insertions(+), 14 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 20a1772..fe6295c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -579,6 +579,7 @@ struct drbd_resource {
 	struct list_head resources;
 	struct res_opts res_opts;
 	struct mutex conf_update;	/* mutex for ready-copy-update of net_conf and disk_conf */
+	struct mutex adm_mutex;		/* mutex to serialize administrative requests */
 	spinlock_t req_lock;
 
 	unsigned susp:1;		/* IO suspended by user */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 865fdb3..05db597 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2570,6 +2570,7 @@ struct drbd_resource *drbd_create_resource(const char *name)
 	INIT_LIST_HEAD(&resource->connections);
 	list_add_tail_rcu(&resource->resources, &drbd_resources);
 	mutex_init(&resource->conf_update);
+	mutex_init(&resource->adm_mutex);
 	spin_lock_init(&resource->req_lock);
 	return resource;
 
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 118ac72..bb36792 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -115,6 +115,10 @@ int drbd_msg_put_info(struct sk_buff *skb, const char *info)
  * and per-family private info->pointers.
  * But we need to stay compatible with older kernels.
  * If it returns successfully, adm_ctx members are valid.
+ *
+ * At this point, we still rely on the global genl_lock().
+ * If we want to avoid that, and allow "genl_family.parallel_ops", we may need
+ * to add additional synchronization against object destruction/modification.
  */
 #define DRBD_ADM_NEED_MINOR	1
 #define DRBD_ADM_NEED_RESOURCE	2
@@ -166,7 +170,7 @@ static int drbd_adm_prepare(struct drbd_config_context *adm_ctx,
 		if (err)
 			goto fail;
 
-		/* and assign stuff to the global adm_ctx */
+		/* and assign stuff to the adm_ctx */
 		nla = nested_attr_tb[__nla_type(T_ctx_volume)];
 		if (nla)
 			adm_ctx->volume = nla_get_u32(nla);
@@ -186,6 +190,13 @@ static int drbd_adm_prepare(struct drbd_config_context *adm_ctx,
 
 	adm_ctx->minor = d_in->minor;
 	adm_ctx->device = minor_to_device(d_in->minor);
+
+	/* We are protected by the global genl_lock().
+	 * But we may explicitly drop it/retake it in drbd_adm_set_role(),
+	 * so make sure this object stays around. */
+	if (adm_ctx->device)
+		kref_get(&adm_ctx->device->kref);
+
 	if (adm_ctx->resource_name) {
 		adm_ctx->resource = drbd_find_resource(adm_ctx->resource_name);
 	}
@@ -241,6 +252,14 @@ static int drbd_adm_prepare(struct drbd_config_context *adm_ctx,
 		return ERR_INVALID_REQUEST;
 	}
 
+	/* still, provide adm_ctx->resource always, if possible. */
+	if (!adm_ctx->resource) {
+		adm_ctx->resource = adm_ctx->device ? adm_ctx->device->resource
+			: adm_ctx->connection ? adm_ctx->connection->resource : NULL;
+		if (adm_ctx->resource)
+			kref_get(&adm_ctx->resource->kref);
+	}
+
 	return NO_ERROR;
 
 fail:
@@ -252,6 +271,10 @@ fail:
 static int drbd_adm_finish(struct drbd_config_context *adm_ctx,
 	struct genl_info *info, int retcode)
 {
+	if (adm_ctx->device) {
+		kref_put(&adm_ctx->device->kref, drbd_destroy_device);
+		adm_ctx->device = NULL;
+	}
 	if (adm_ctx->connection) {
 		kref_put(&adm_ctx->connection->kref, &drbd_destroy_connection);
 		adm_ctx->connection = NULL;
@@ -635,11 +658,11 @@ drbd_set_role(struct drbd_device *device, enum drbd_role new_role, int force)
 			put_ldev(device);
 		}
 	} else {
-		mutex_lock(&device->resource->conf_update);
+		/* Called from drbd_adm_set_role only.
+		 * We are still holding the conf_update mutex. */
 		nc = first_peer_device(device)->connection->net_conf;
 		if (nc)
 			nc->discard_my_data = 0; /* without copy; single bit op is atomic */
-		mutex_unlock(&device->resource->conf_update);
 
 		set_disk_ro(device->vdisk, false);
 		if (get_ldev(device)) {
@@ -701,11 +724,16 @@ int drbd_adm_set_role(struct sk_buff *skb, struct genl_info *info)
 			goto out;
 		}
 	}
+	genl_unlock();
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 
 	if (info->genlhdr->cmd == DRBD_ADM_PRIMARY)
 		retcode = drbd_set_role(adm_ctx.device, R_PRIMARY, parms.assume_uptodate);
 	else
 		retcode = drbd_set_role(adm_ctx.device, R_SECONDARY, 0);
+
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
+	genl_lock();
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -1251,9 +1279,10 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info)
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
-		goto out;
+		goto finish;
 
 	device = adm_ctx.device;
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 
 	/* we also need a disk
 	 * to change the options on */
@@ -1368,6 +1397,8 @@ fail_unlock:
 success:
 	put_ldev(device);
  out:
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
+ finish:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
@@ -1397,6 +1428,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 		goto finish;
 
 	device = adm_ctx.device;
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	conn_reconfig_start(first_peer_device(device)->connection);
 
 	/* if you want to reconfigure, please tear down first */
@@ -1781,6 +1813,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 	kobject_uevent(&disk_to_dev(device->vdisk)->kobj, KOBJ_CHANGE);
 	put_ldev(device);
 	conn_reconfig_done(first_peer_device(device)->connection);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 
@@ -1803,7 +1836,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 	kfree(new_disk_conf);
 	lc_destroy(resync_lru);
 	kfree(new_plan);
-
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
  finish:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -1864,7 +1897,9 @@ int drbd_adm_detach(struct sk_buff *skb, struct genl_info *info)
 		}
 	}
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	retcode = adm_detach(adm_ctx.device, parms.force_detach);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2053,9 +2088,10 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
-		goto out;
+		goto finish;
 
 	connection = adm_ctx.connection;
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 
 	new_net_conf = kzalloc(sizeof(struct net_conf), GFP_KERNEL);
 	if (!new_net_conf) {
@@ -2153,6 +2189,8 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
  done:
 	conn_reconfig_done(connection);
  out:
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
+ finish:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
@@ -2202,6 +2240,7 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 		}
 	}
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	connection = first_connection(adm_ctx.resource);
 	conn_reconfig_start(connection);
 
@@ -2271,6 +2310,7 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
 	retcode = conn_request_state(connection, NS(conn, C_UNCONNECTED), CS_VERBOSE);
 
 	conn_reconfig_done(connection);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 
@@ -2279,6 +2319,7 @@ fail:
 	kfree(new_net_conf);
 
 	conn_reconfig_done(connection);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2367,11 +2408,13 @@ int drbd_adm_disconnect(struct sk_buff *skb, struct genl_info *info)
 		}
 	}
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	rv = conn_try_disconnect(connection, parms.force_disconnect);
 	if (rv < SS_SUCCESS)
 		retcode = rv;  /* FIXME: Type mismatch. */
 	else
 		retcode = NO_ERROR;
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
  fail:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2410,8 +2453,9 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
-		goto fail;
+		goto finish;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	device = adm_ctx.device;
 	if (!get_ldev(device)) {
 		retcode = ERR_NO_DISK;
@@ -2517,6 +2561,8 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
 	}
 
  fail:
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
+ finish:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 
@@ -2549,12 +2595,14 @@ int drbd_adm_resource_opts(struct sk_buff *skb, struct genl_info *info)
 		goto fail;
 	}
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	err = set_resource_options(adm_ctx.resource, &res_opts);
 	if (err) {
 		retcode = ERR_INVALID_REQUEST;
 		if (err == -ENOMEM)
 			retcode = ERR_NOMEM;
 	}
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 
 fail:
 	drbd_adm_finish(&adm_ctx, info, retcode);
@@ -2573,6 +2621,7 @@ int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info)
 	if (retcode != NO_ERROR)
 		goto out;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	device = adm_ctx.device;
 
 	/* If there is still bitmap IO pending, probably because of a previous
@@ -2596,7 +2645,7 @@ int drbd_adm_invalidate(struct sk_buff *skb, struct genl_info *info)
 	} else
 		retcode = drbd_request_state(device, NS(conn, C_STARTING_SYNC_T));
 	drbd_resume_io(device);
-
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2614,7 +2663,9 @@ static int drbd_adm_simple_request_state(struct sk_buff *skb, struct genl_info *
 	if (retcode != NO_ERROR)
 		goto out;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	retcode = drbd_request_state(adm_ctx.device, mask, val);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2641,6 +2692,7 @@ int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info)
 	if (retcode != NO_ERROR)
 		goto out;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	device = adm_ctx.device;
 
 	/* If there is still bitmap IO pending, probably because of a previous
@@ -2667,7 +2719,7 @@ int drbd_adm_invalidate_peer(struct sk_buff *skb, struct genl_info *info)
 	} else
 		retcode = drbd_request_state(device, NS(conn, C_STARTING_SYNC_S));
 	drbd_resume_io(device);
-
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2684,8 +2736,10 @@ int drbd_adm_pause_sync(struct sk_buff *skb, struct genl_info *info)
 	if (retcode != NO_ERROR)
 		goto out;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	if (drbd_request_state(adm_ctx.device, NS(user_isp, 1)) == SS_NOTHING_TO_DO)
 		retcode = ERR_PAUSE_IS_SET;
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2703,6 +2757,7 @@ int drbd_adm_resume_sync(struct sk_buff *skb, struct genl_info *info)
 	if (retcode != NO_ERROR)
 		goto out;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	if (drbd_request_state(adm_ctx.device, NS(user_isp, 0)) == SS_NOTHING_TO_DO) {
 		s = adm_ctx.device->state;
 		if (s.conn == C_PAUSED_SYNC_S || s.conn == C_PAUSED_SYNC_T) {
@@ -2712,7 +2767,7 @@ int drbd_adm_resume_sync(struct sk_buff *skb, struct genl_info *info)
 			retcode = ERR_PAUSE_IS_CLEAR;
 		}
 	}
-
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -2735,6 +2790,7 @@ int drbd_adm_resume_io(struct sk_buff *skb, struct genl_info *info)
 	if (retcode != NO_ERROR)
 		goto out;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	device = adm_ctx.device;
 	if (test_bit(NEW_CUR_UUID, &device->flags)) {
 		drbd_uuid_new_current(device);
@@ -2749,7 +2805,7 @@ int drbd_adm_resume_io(struct sk_buff *skb, struct genl_info *info)
 			tl_restart(first_peer_device(device)->connection, FAIL_FROZEN_DISK_IO);
 	}
 	drbd_resume_io(device);
-
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -3182,6 +3238,8 @@ int drbd_adm_start_ov(struct sk_buff *skb, struct genl_info *info)
 			goto out;
 		}
 	}
+	mutex_lock(&adm_ctx.resource->adm_mutex);
+
 	/* w_make_ov_request expects position to be aligned */
 	device->ov_start_sector = parms.ov_start_sector & ~(BM_SECT_PER_BIT-1);
 	device->ov_stop_sector = parms.ov_stop_sector;
@@ -3192,6 +3250,8 @@ int drbd_adm_start_ov(struct sk_buff *skb, struct genl_info *info)
 	wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
 	retcode = drbd_request_state(device, NS(conn, C_VERIFY_S));
 	drbd_resume_io(device);
+
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -3224,6 +3284,7 @@ int drbd_adm_new_c_uuid(struct sk_buff *skb, struct genl_info *info)
 		}
 	}
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	mutex_lock(device->state_mutex); /* Protects us against serialized state changes. */
 
 	if (!get_ldev(device)) {
@@ -3268,6 +3329,7 @@ out_dec:
 	put_ldev(device);
 out:
 	mutex_unlock(device->state_mutex);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out_nolock:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -3324,6 +3386,7 @@ int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info)
 		goto out;
 	}
 
+	/* not yet safe for genl_family.parallel_ops */
 	if (!conn_create(adm_ctx.resource_name, &res_opts))
 		retcode = ERR_NOMEM;
 out:
@@ -3363,7 +3426,9 @@ int drbd_adm_new_minor(struct sk_buff *skb, struct genl_info *info)
 		goto out;
 	}
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	retcode = drbd_create_device(&adm_ctx, dh->minor);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -3395,7 +3460,9 @@ int drbd_adm_del_minor(struct sk_buff *skb, struct genl_info *info)
 	if (retcode != NO_ERROR)
 		goto out;
 
+	mutex_lock(&adm_ctx.resource->adm_mutex);
 	retcode = adm_del_minor(adm_ctx.device);
+	mutex_unlock(&adm_ctx.resource->adm_mutex);
 out:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
@@ -3414,9 +3481,10 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
-		goto out;
+		goto finish;
 
 	resource = adm_ctx.resource;
+	mutex_lock(&resource->adm_mutex);
 	/* demote */
 	for_each_connection(connection, resource) {
 		struct drbd_peer_device *peer_device;
@@ -3467,8 +3535,9 @@ int drbd_adm_down(struct sk_buff *skb, struct genl_info *info)
 	synchronize_rcu();
 	drbd_free_resource(resource);
 	retcode = NO_ERROR;
-
 out:
+	mutex_unlock(&resource->adm_mutex);
+finish:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
@@ -3484,9 +3553,10 @@ int drbd_adm_del_resource(struct sk_buff *skb, struct genl_info *info)
 	if (!adm_ctx.reply_skb)
 		return retcode;
 	if (retcode != NO_ERROR)
-		goto out;
+		goto finish;
 
 	resource = adm_ctx.resource;
+	mutex_lock(&resource->adm_mutex);
 	for_each_connection(connection, resource) {
 		if (connection->cstate > C_STANDALONE) {
 			retcode = ERR_NET_CONFIGURED;
@@ -3505,6 +3575,8 @@ int drbd_adm_del_resource(struct sk_buff *skb, struct genl_info *info)
 	drbd_free_resource(resource);
 	retcode = NO_ERROR;
 out:
+	mutex_unlock(&resource->adm_mutex);
+finish:
 	drbd_adm_finish(&adm_ctx, info, retcode);
 	return 0;
 }
-- 
1.9.1

[Drbd-dev] [PATCH 12/24] drbd: prepare receiving side for REQ_DISCARD

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

If the receiver needs to serve a discard request on a queue that does
not announce to be discard cabable, it falls back to do synchronous
blkdev_issue_zeroout().

We expect only "reasonably" large (up to one activity log extent?)
discard requests.

We do this to not to not block the receiver for too long in this
fallback code path, and to not set/clear too many bits inside one
spinlock_irq_save() in drbd_set_in_sync/drbd_set_out_of_sync,

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_actlog.c   |  6 +--
 drivers/block/drbd/drbd_int.h      | 19 ++++++++-
 drivers/block/drbd/drbd_protocol.h | 10 +++++
 drivers/block/drbd/drbd_receiver.c | 79 +++++++++++++++++++++++++++++---------
 drivers/block/drbd/drbd_worker.c   | 12 ++++--
 5 files changed, 100 insertions(+), 26 deletions(-)

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 8dd09a7..8fc5d71 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -845,7 +845,7 @@ void __drbd_set_in_sync(struct drbd_device *device, sector_t sector, int size,
 	int wake_up = 0;
 	unsigned long flags;
 
-	if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
+	if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_SIZE) {
 		drbd_err(device, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
 				(unsigned long long)sector, size);
 		return;
@@ -919,7 +919,7 @@ int __drbd_set_out_of_sync(struct drbd_device *device, sector_t sector, int size
 	if (size == 0)
 		return 0;
 
-	if (size < 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
+	if (size < 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_SIZE) {
 		drbd_err(device, "sector: %llus, size: %d\n",
 			(unsigned long long)sector, size);
 		return 0;
@@ -1286,7 +1286,7 @@ void drbd_rs_failed_io(struct drbd_device *device, sector_t sector, int size)
 	sector_t esector, nr_sectors;
 	int wake_up = 0;
 
-	if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
+	if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_SIZE) {
 		drbd_err(device, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
 				(unsigned long long)sector, size);
 		return;
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index fe6295c..29123df 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -382,6 +382,12 @@ enum {
 	__EE_CALL_AL_COMPLETE_IO,
 	__EE_MAY_SET_IN_SYNC,
 
+	/* is this a TRIM aka REQ_DISCARD? */
+	__EE_IS_TRIM,
+	/* our lower level cannot handle trim,
+	 * and we want to fall back to zeroout instead */
+	__EE_IS_TRIM_USE_ZEROOUT,
+
 	/* In case a barrier failed,
 	 * we need to resubmit without the barrier flag. */
 	__EE_RESUBMITTED,
@@ -405,7 +411,9 @@ enum {
 };
 #define EE_CALL_AL_COMPLETE_IO (1<<__EE_CALL_AL_COMPLETE_IO)
 #define EE_MAY_SET_IN_SYNC     (1<<__EE_MAY_SET_IN_SYNC)
-#define	EE_RESUBMITTED         (1<<__EE_RESUBMITTED)
+#define EE_IS_TRIM             (1<<__EE_IS_TRIM)
+#define EE_IS_TRIM_USE_ZEROOUT (1<<__EE_IS_TRIM_USE_ZEROOUT)
+#define EE_RESUBMITTED         (1<<__EE_RESUBMITTED)
 #define EE_WAS_ERROR           (1<<__EE_WAS_ERROR)
 #define EE_HAS_DIGEST          (1<<__EE_HAS_DIGEST)
 #define EE_RESTART_REQUESTS	(1<<__EE_RESTART_REQUESTS)
@@ -1162,6 +1170,12 @@ struct bm_extent {
 #define DRBD_MAX_SIZE_H80_PACKET (1U << 15) /* Header 80 only allows packets up to 32KiB data */
 #define DRBD_MAX_BIO_SIZE_P95    (1U << 17) /* Protocol 95 to 99 allows bios up to 128KiB */
 
+/* For now, don't allow more than one activity log extent worth of data
+ * to be discarded in one go. We may need to rework drbd_al_begin_io()
+ * to allow for even larger discard ranges */
+#define DRBD_MAX_DISCARD_SIZE	AL_EXTENT_SIZE
+#define DRBD_MAX_DISCARD_SECTORS (DRBD_MAX_DISCARD_SIZE >> 9)
+
 extern int  drbd_bm_init(struct drbd_device *device);
 extern int  drbd_bm_resize(struct drbd_device *device, sector_t sectors, int set_new_bits);
 extern void drbd_bm_cleanup(struct drbd_device *device);
@@ -1359,6 +1373,8 @@ extern int w_start_resync(struct drbd_work *, int);
 extern void resync_timer_fn(unsigned long data);
 extern void start_resync_timer_fn(unsigned long data);
 
+extern void drbd_endio_write_sec_final(struct drbd_peer_request *peer_req);
+
 /* drbd_receiver.c */
 extern int drbd_receiver(struct drbd_thread *thi);
 extern int drbd_asender(struct drbd_thread *thi);
@@ -1370,6 +1386,7 @@ extern int drbd_submit_peer_request(struct drbd_device *,
 extern int drbd_free_peer_reqs(struct drbd_device *, struct list_head *);
 extern struct drbd_peer_request *drbd_alloc_peer_req(struct drbd_peer_device *, u64,
 						     sector_t, unsigned int,
+						     bool,
 						     gfp_t) __must_hold(local);
 extern void __drbd_free_peer_req(struct drbd_device *, struct drbd_peer_request *,
 				 int);
diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h
index 3c04ec0..478c63d 100644
--- a/drivers/block/drbd/drbd_protocol.h
+++ b/drivers/block/drbd/drbd_protocol.h
@@ -54,6 +54,11 @@ enum drbd_packet {
 	P_CONN_ST_CHG_REPLY   = 0x2b, /* meta sock: Connection side state req reply */
 	P_RETRY_WRITE	      = 0x2c, /* Protocol C: retry conflicting write request */
 	P_PROTOCOL_UPDATE     = 0x2d, /* data sock: is used in established connections */
+        /* 0x2e to 0x30 reserved, used in drbd 9 */
+
+	/* REQ_DISCARD. We used "discard" in different contexts before,
+	 * which is why I chose TRIM here, to disambiguate. */
+	P_TRIM                = 0x31,
 
 	P_MAY_IGNORE	      = 0x100, /* Flag to test if (cmd > P_MAY_IGNORE) ... */
 	P_MAX_OPT_CMD	      = 0x101,
@@ -119,6 +124,11 @@ struct p_data {
 	u32	    dp_flags;
 } __packed;
 
+struct p_trim {
+	struct p_data p_data;
+	u32	    size;	/* == bio->bi_size */
+} __packed;
+
 /*
  * commands which share a struct:
  *  p_block_ack:
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 10d2dcb..9640b64 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -65,7 +65,7 @@ enum finish_epoch {
 static int drbd_do_features(struct drbd_connection *connection);
 static int drbd_do_auth(struct drbd_connection *connection);
 static int drbd_disconnected(struct drbd_peer_device *);
-
+static void conn_wait_active_ee_empty(struct drbd_connection *connection);
 static enum finish_epoch drbd_may_finish_epoch(struct drbd_connection *, struct drbd_epoch *, enum epoch_event);
 static int e_end_block(struct drbd_work *, int);
 
@@ -338,7 +338,7 @@ You must not have the req_lock:
 
 struct drbd_peer_request *
 drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
-		    unsigned int data_size, gfp_t gfp_mask) __must_hold(local)
+		    unsigned int data_size, bool has_payload, gfp_t gfp_mask) __must_hold(local)
 {
 	struct drbd_device *device = peer_device->device;
 	struct drbd_peer_request *peer_req;
@@ -355,7 +355,7 @@ drbd_alloc_peer_req(struct drbd_peer_device *peer_device, u64 id, sector_t secto
 		return NULL;
 	}
 
-	if (data_size) {
+	if (has_payload && data_size) {
 		page = drbd_alloc_pages(peer_device, nr_pages, (gfp_mask & __GFP_WAIT));
 		if (!page)
 			goto fail;
@@ -1325,6 +1325,20 @@ int drbd_submit_peer_request(struct drbd_device *device,
 	unsigned nr_pages = (ds + PAGE_SIZE -1) >> PAGE_SHIFT;
 	int err = -ENOMEM;
 
+	if (peer_req->flags & EE_IS_TRIM_USE_ZEROOUT) {
+		/* wait for all pending IO completions, before we start
+		 * zeroing things out. */
+		conn_wait_active_ee_empty(first_peer_device(device)->connection);
+		if (blkdev_issue_zeroout(device->ldev->backing_bdev,
+			sector, ds >> 9, GFP_NOIO))
+			peer_req->flags |= EE_WAS_ERROR;
+		drbd_endio_write_sec_final(peer_req);
+		return 0;
+	}
+
+	if (peer_req->flags & EE_IS_TRIM)
+		nr_pages = 0; /* discards don't have any payload. */
+
 	/* In most cases, we will only need one bio.  But in case the lower
 	 * level restrictions happen to be different at this offset on this
 	 * side than those of the sending peer, we may need to submit the
@@ -1336,7 +1350,7 @@ int drbd_submit_peer_request(struct drbd_device *device,
 next_bio:
 	bio = bio_alloc(GFP_NOIO, nr_pages);
 	if (!bio) {
-		drbd_err(device, "submit_ee: Allocation of a bio failed\n");
+		drbd_err(device, "submit_ee: Allocation of a bio failed (nr_pages=%u)\n", nr_pages);
 		goto fail;
 	}
 	/* > peer_req->i.sector, unless this is the first bio */
@@ -1350,6 +1364,11 @@ next_bio:
 	bios = bio;
 	++n_bios;
 
+	if (rw & REQ_DISCARD) {
+		bio->bi_iter.bi_size = ds;
+		goto submit;
+	}
+
 	page_chain_for_each(page) {
 		unsigned len = min_t(unsigned, ds, PAGE_SIZE);
 		if (!bio_add_page(bio, page, len, 0)) {
@@ -1370,8 +1389,9 @@ next_bio:
 		sector += len >> 9;
 		--nr_pages;
 	}
-	D_ASSERT(device, page == NULL);
 	D_ASSERT(device, ds == 0);
+submit:
+	D_ASSERT(device, page == NULL);
 
 	atomic_set(&peer_req->pending_bios, n_bios);
 	do {
@@ -1500,19 +1520,21 @@ static int receive_Barrier(struct drbd_connection *connection, struct packet_inf
  * and from receive_Data */
 static struct drbd_peer_request *
 read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
-	      int data_size) __must_hold(local)
+	      struct packet_info *pi) __must_hold(local)
 {
 	struct drbd_device *device = peer_device->device;
 	const sector_t capacity = drbd_get_capacity(device->this_bdev);
 	struct drbd_peer_request *peer_req;
 	struct page *page;
 	int dgs, ds, err;
+	int data_size = pi->size;
 	void *dig_in = peer_device->connection->int_dig_in;
 	void *dig_vv = peer_device->connection->int_dig_vv;
 	unsigned long *data;
+	struct p_trim *trim = (pi->cmd == P_TRIM) ? pi->data : NULL;
 
 	dgs = 0;
-	if (peer_device->connection->peer_integrity_tfm) {
+	if (!trim && peer_device->connection->peer_integrity_tfm) {
 		dgs = crypto_hash_digestsize(peer_device->connection->peer_integrity_tfm);
 		/*
 		 * FIXME: Receive the incoming digest into the receive buffer
@@ -1524,9 +1546,15 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 		data_size -= dgs;
 	}
 
+	if (trim) {
+		D_ASSERT(peer_device, data_size == 0);
+		data_size = be32_to_cpu(trim->size);
+	}
+
 	if (!expect(IS_ALIGNED(data_size, 512)))
 		return NULL;
-	if (!expect(data_size <= DRBD_MAX_BIO_SIZE))
+	/* prepare for larger trim requests. */
+	if (!trim && !expect(data_size <= DRBD_MAX_BIO_SIZE))
 		return NULL;
 
 	/* even though we trust out peer,
@@ -1542,11 +1570,11 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector,
 	/* GFP_NOIO, because we must not cause arbitrary write-out: in a DRBD
 	 * "criss-cross" setup, that might cause write-out on some other DRBD,
 	 * which in turn might block on the other node at this very place.  */
-	peer_req = drbd_alloc_peer_req(peer_device, id, sector, data_size, GFP_NOIO);
+	peer_req = drbd_alloc_peer_req(peer_device, id, sector, data_size, trim == NULL, GFP_NOIO);
 	if (!peer_req)
 		return NULL;
 
-	if (!data_size)
+	if (trim)
 		return peer_req;
 
 	ds = data_size;
@@ -1686,12 +1714,12 @@ static int e_end_resync_block(struct drbd_work *w, int unused)
 }
 
 static int recv_resync_read(struct drbd_peer_device *peer_device, sector_t sector,
-			    int data_size) __releases(local)
+			    struct packet_info *pi) __releases(local)
 {
 	struct drbd_device *device = peer_device->device;
 	struct drbd_peer_request *peer_req;
 
-	peer_req = read_in_block(peer_device, ID_SYNCER, sector, data_size);
+	peer_req = read_in_block(peer_device, ID_SYNCER, sector, pi);
 	if (!peer_req)
 		goto fail;
 
@@ -1707,7 +1735,7 @@ static int recv_resync_read(struct drbd_peer_device *peer_device, sector_t secto
 	list_add(&peer_req->w.list, &device->sync_ee);
 	spin_unlock_irq(&device->resource->req_lock);
 
-	atomic_add(data_size >> 9, &device->rs_sect_ev);
+	atomic_add(pi->size >> 9, &device->rs_sect_ev);
 	if (drbd_submit_peer_request(device, peer_req, WRITE, DRBD_FAULT_RS_WR) == 0)
 		return 0;
 
@@ -1795,7 +1823,7 @@ static int receive_RSDataReply(struct drbd_connection *connection, struct packet
 		/* data is submitted to disk within recv_resync_read.
 		 * corresponding put_ldev done below on error,
 		 * or in drbd_peer_request_endio. */
-		err = recv_resync_read(peer_device, sector, pi->size);
+		err = recv_resync_read(peer_device, sector, pi);
 	} else {
 		if (__ratelimit(&drbd_ratelimit_state))
 			drbd_err(device, "Can not write resync data to local disk.\n");
@@ -2206,7 +2234,7 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
 	 */
 
 	sector = be64_to_cpu(p->sector);
-	peer_req = read_in_block(peer_device, p->block_id, sector, pi->size);
+	peer_req = read_in_block(peer_device, p->block_id, sector, pi);
 	if (!peer_req) {
 		put_ldev(device);
 		return -EIO;
@@ -2216,7 +2244,15 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
 
 	dp_flags = be32_to_cpu(p->dp_flags);
 	rw |= wire_flags_to_bio(dp_flags);
-	if (peer_req->pages == NULL) {
+	if (pi->cmd == P_TRIM) {
+		struct request_queue *q = bdev_get_queue(device->ldev->backing_bdev);
+		peer_req->flags |= EE_IS_TRIM;
+		if (!blk_queue_discard(q))
+			peer_req->flags |= EE_IS_TRIM_USE_ZEROOUT;
+		D_ASSERT(peer_device, peer_req->i.size > 0);
+		D_ASSERT(peer_device, rw & REQ_DISCARD);
+		D_ASSERT(peer_device, peer_req->pages == NULL);
+	} else if (peer_req->pages == NULL) {
 		D_ASSERT(device, peer_req->i.size == 0);
 		D_ASSERT(device, dp_flags & DP_FLUSH);
 	}
@@ -2252,7 +2288,12 @@ static int receive_Data(struct drbd_connection *connection, struct packet_info *
 		update_peer_seq(peer_device, peer_seq);
 		spin_lock_irq(&device->resource->req_lock);
 	}
-	list_add(&peer_req->w.list, &device->active_ee);
+	/* if we use the zeroout fallback code, we process synchronously
+	 * and we wait for all pending requests, respectively wait for
+	 * active_ee to become empty in drbd_submit_peer_request();
+	 * better not add ourselves here. */
+	if ((peer_req->flags & EE_IS_TRIM_USE_ZEROOUT) == 0)
+		list_add(&peer_req->w.list, &device->active_ee);
 	spin_unlock_irq(&device->resource->req_lock);
 
 	if (device->state.conn == C_SYNC_TARGET)
@@ -2451,7 +2492,8 @@ static int receive_DataRequest(struct drbd_connection *connection, struct packet
 	/* GFP_NOIO, because we must not cause arbitrary write-out: in a DRBD
 	 * "criss-cross" setup, that might cause write-out on some other DRBD,
 	 * which in turn might block on the other node at this very place.  */
-	peer_req = drbd_alloc_peer_req(peer_device, p->block_id, sector, size, GFP_NOIO);
+	peer_req = drbd_alloc_peer_req(peer_device, p->block_id, sector, size,
+			true /* has real payload */, GFP_NOIO);
 	if (!peer_req) {
 		put_ldev(device);
 		return -ENOMEM;
@@ -4438,6 +4480,7 @@ static struct data_cmd drbd_cmd_handler[] = {
 	[P_OUT_OF_SYNC]     = { 0, sizeof(struct p_block_desc), receive_out_of_sync },
 	[P_CONN_ST_CHG_REQ] = { 0, sizeof(struct p_req_state), receive_req_conn_state },
 	[P_PROTOCOL_UPDATE] = { 1, sizeof(struct p_protocol), receive_protocol },
+	[P_TRIM]	    = { 0, sizeof(struct p_trim), receive_Data },
 };
 
 static void drbdd(struct drbd_connection *connection)
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 7e633ca..5fd4eae 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -118,7 +118,7 @@ static void drbd_endio_read_sec_final(struct drbd_peer_request *peer_req) __rele
 
 /* writes on behalf of the partner, or resync writes,
  * "submitted" by the receiver, final stage.  */
-static void drbd_endio_write_sec_final(struct drbd_peer_request *peer_req) __releases(local)
+void drbd_endio_write_sec_final(struct drbd_peer_request *peer_req) __releases(local)
 {
 	unsigned long flags = 0;
 	struct drbd_peer_device *peer_device = peer_req->peer_device;
@@ -150,7 +150,9 @@ static void drbd_endio_write_sec_final(struct drbd_peer_request *peer_req) __rel
 
 	do_wake = list_empty(block_id == ID_SYNCER ? &device->sync_ee : &device->active_ee);
 
-	if (test_bit(__EE_WAS_ERROR, &peer_req->flags))
+	/* FIXME do we want to detach for failed REQ_DISCARD?
+	 * ((peer_req->flags & (EE_WAS_ERROR|EE_IS_TRIM)) == EE_WAS_ERROR) */
+	if (peer_req->flags & EE_WAS_ERROR)
 		__drbd_chk_io_error(device, DRBD_WRITE_ERROR);
 	spin_unlock_irqrestore(&device->resource->req_lock, flags);
 
@@ -176,10 +178,12 @@ void drbd_peer_request_endio(struct bio *bio, int error)
 	struct drbd_device *device = peer_req->peer_device->device;
 	int uptodate = bio_flagged(bio, BIO_UPTODATE);
 	int is_write = bio_data_dir(bio) == WRITE;
+	int is_discard = !!(bio->bi_rw & REQ_DISCARD);
 
 	if (error && __ratelimit(&drbd_ratelimit_state))
 		drbd_warn(device, "%s: error=%d s=%llus\n",
-				is_write ? "write" : "read", error,
+				is_write ? (is_discard ? "discard" : "write")
+					: "read", error,
 				(unsigned long long)peer_req->i.sector);
 	if (!error && !uptodate) {
 		if (__ratelimit(&drbd_ratelimit_state))
@@ -395,7 +399,7 @@ static int read_for_csum(struct drbd_peer_device *peer_device, sector_t sector,
 	/* GFP_TRY, because if there is no memory available right now, this may
 	 * be rescheduled for later. It is "only" background resync, after all. */
 	peer_req = drbd_alloc_peer_req(peer_device, ID_SYNCER /* unused */, sector,
-				       size, GFP_TRY);
+				       size, true /* has real payload */, GFP_TRY);
 	if (!peer_req)
 		goto defer;
 
-- 
1.9.1

[Drbd-dev] [PATCH 13/24] drbd: prepare sending side for REQ_DISCARD

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

Note that I do NOT call __drbd_chk_io_error for failed REQ_DISCARD.
That may be wrong, though, or needs to differ between EOPNOTSUPP and
other errors...

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_main.c   | 15 +++++++++++++--
 drivers/block/drbd/drbd_req.c    |  7 +++++++
 drivers/block/drbd/drbd_req.h    |  5 ++++-
 drivers/block/drbd/drbd_worker.c |  7 ++++++-
 4 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 05db597..960645c 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1607,8 +1607,8 @@ static u32 bio_flags_to_wire(struct drbd_connection *connection, unsigned long b
 		return bi_rw & REQ_SYNC ? DP_RW_SYNC : 0;
 }
 
-/* Used to send write requests
- * R_PRIMARY -> Peer	(P_DATA)
+/* Used to send write or TRIM aka REQ_DISCARD requests
+ * R_PRIMARY -> Peer	(P_DATA, P_TRIM)
  */
 int drbd_send_dblock(struct drbd_peer_device *peer_device, struct drbd_request *req)
 {
@@ -1640,6 +1640,16 @@ int drbd_send_dblock(struct drbd_peer_device *peer_device, struct drbd_request *
 			dp_flags |= DP_SEND_WRITE_ACK;
 	}
 	p->dp_flags = cpu_to_be32(dp_flags);
+
+	if (dp_flags & DP_DISCARD) {
+		struct p_trim *t = (struct p_trim*)p;
+		t->size = cpu_to_be32(req->i.size);
+		err = __send_command(peer_device->connection, device->vnr, sock, P_TRIM, sizeof(*t), NULL, 0);
+		goto out;
+	}
+
+	/* our digest is still only over the payload.
+	 * TRIM does not carry any payload. */
 	if (dgs)
 		drbd_csum_bio(peer_device->connection->integrity_tfm, req->master_bio, p + 1);
 	err = __send_command(peer_device->connection, device->vnr, sock, P_DATA, sizeof(*p) + dgs, NULL, req->i.size);
@@ -1675,6 +1685,7 @@ int drbd_send_dblock(struct drbd_peer_device *peer_device, struct drbd_request *
 		     ... Be noisy about digest too large ...
 		} */
 	}
+out:
 	mutex_unlock(&sock->mutex);  /* locked by drbd_prepare_command() */
 
 	return err;
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 3779c8d..7aadd09 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -522,6 +522,13 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
 		mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
 		break;
 
+	case DISCARD_COMPLETED_NOTSUPP:
+	case DISCARD_COMPLETED_WITH_ERROR:
+		/* I'd rather not detach from local disk just because it
+		 * failed a REQ_DISCARD. */
+		mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
+		break;
+
 	case QUEUE_FOR_NET_READ:
 		/* READ or READA, and
 		 * no local disk,
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index 07cc8e8..8566cd5 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -110,11 +110,14 @@ enum drbd_req_event {
 	BARRIER_ACKED, /* in protocol A and B */
 	DATA_RECEIVED, /* (remote read) */
 
+	COMPLETED_OK,
 	READ_COMPLETED_WITH_ERROR,
 	READ_AHEAD_COMPLETED_WITH_ERROR,
 	WRITE_COMPLETED_WITH_ERROR,
+	DISCARD_COMPLETED_NOTSUPP,
+	DISCARD_COMPLETED_WITH_ERROR,
+
 	ABORT_DISK_IO,
-	COMPLETED_OK,
 	RESEND,
 	FAIL_FROZEN_DISK_IO,
 	RESTART_FROZEN_DISK_IO,
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 5fd4eae..26338be 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -267,7 +267,12 @@ void drbd_request_endio(struct bio *bio, int error)
 
 	/* to avoid recursion in __req_mod */
 	if (unlikely(error)) {
-		what = (bio_data_dir(bio) == WRITE)
+		if (bio->bi_rw & REQ_DISCARD)
+			what = (error == -EOPNOTSUPP)
+				? DISCARD_COMPLETED_NOTSUPP
+				: DISCARD_COMPLETED_WITH_ERROR;
+		else
+			what = (bio_data_dir(bio) == WRITE)
 			? WRITE_COMPLETED_WITH_ERROR
 			: (bio_rw(bio) == READ)
 			  ? READ_COMPLETED_WITH_ERROR
-- 
1.9.1

[Drbd-dev] [PATCH 14/24] drbd: Enable QUEUE_FLAG_DISCARD only if the peer can recieve P_TRIM

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

Allow the user of REQ_DISCARD.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_int.h      |  1 +
 drivers/block/drbd/drbd_nl.c       | 20 ++++++++++++++++++++
 drivers/block/drbd/drbd_protocol.h |  2 ++
 drivers/block/drbd/drbd_receiver.c | 18 ++++++++++++++----
 4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 29123df..d5f39fd 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -618,6 +618,7 @@ struct drbd_connection {
 	struct drbd_socket data;	/* data/barrier/cstate/parameter packets */
 	struct drbd_socket meta;	/* ping/ack (metadata) packets */
 	int agreed_pro_version;		/* actually used protocol version */
+	u32 agreed_features;
 	unsigned long last_received;	/* in jiffies, either socket */
 	unsigned int ko_count;
 
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index bb36792..2364b78 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1133,6 +1133,26 @@ static void drbd_setup_queue_param(struct drbd_device *device, unsigned int max_
 
 	if (get_ldev_if_state(device, D_ATTACHING)) {
 		struct request_queue * const b = device->ldev->backing_bdev->bd_disk->queue;
+		struct drbd_connection *connection = first_peer_device(device)->connection;
+
+		if (blk_queue_discard(b) &&
+		    (connection->cstate < C_CONNECTED || connection->agreed_features & FF_TRIM)) {
+			/* inherit from backing queue */
+			q->limits.discard_zeroes_data = 1;
+			/* For now, don't allow more than one activity log extent worth of data
+			 * to be discarded in one go. We may need to rework drbd_al_begin_io()
+			 * to allow for even larger discard ranges */
+			q->limits.max_discard_sectors = DRBD_MAX_DISCARD_SECTORS;
+
+			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
+			/* REALLY? Is stacking secdiscard "legal"? */
+			if (blk_queue_secdiscard(b))
+				queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, q);
+		} else {
+			q->limits.max_discard_sectors = 0;
+			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
+			queue_flag_clear_unlocked(QUEUE_FLAG_SECDISCARD, q);
+		}
 
 		blk_queue_stack_limits(q, b);
 
diff --git a/drivers/block/drbd/drbd_protocol.h b/drivers/block/drbd/drbd_protocol.h
index 478c63d..2da9104a 100644
--- a/drivers/block/drbd/drbd_protocol.h
+++ b/drivers/block/drbd/drbd_protocol.h
@@ -160,6 +160,8 @@ struct p_block_req {
  *   ReportParams
  */
 
+#define FF_TRIM      1
+
 struct p_connection_features {
 	u32 protocol_min;
 	u32 feature_flags;
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 9640b64..3fa3b78 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -46,9 +46,10 @@
 #include "drbd_int.h"
 #include "drbd_protocol.h"
 #include "drbd_req.h"
-
 #include "drbd_vli.h"
 
+#define PRO_FEATURES (FF_TRIM)
+
 struct packet_info {
 	enum drbd_packet cmd;
 	unsigned int size;
@@ -3705,6 +3706,13 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 		put_ldev(device);
 	}
 
+	device->peer_max_bio_size = be32_to_cpu(p->max_bio_size);
+	drbd_reconsider_max_bio_size(device);
+	/* Leave drbd_reconsider_max_bio_size() before drbd_determine_dev_size().
+	   In case we cleared the QUEUE_FLAG_DISCARD from our queue in
+	   drbd_reconsider_max_bio_size(), we can be sure that after
+	   drbd_determine_dev_size() no REQ_DISCARDs are in the queue. */
+
 	ddsf = be16_to_cpu(p->dds_flags);
 	if (get_ldev(device)) {
 		dd = drbd_determine_dev_size(device, ddsf, NULL);
@@ -3717,9 +3725,6 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
 		drbd_set_my_capacity(device, p_size);
 	}
 
-	device->peer_max_bio_size = be32_to_cpu(p->max_bio_size);
-	drbd_reconsider_max_bio_size(device);
-
 	if (get_ldev(device)) {
 		if (device->ldev->known_size != drbd_get_capacity(device->ldev->backing_bdev)) {
 			device->ldev->known_size = drbd_get_capacity(device->ldev->backing_bdev);
@@ -4688,6 +4693,7 @@ static int drbd_send_features(struct drbd_connection *connection)
 	memset(p, 0, sizeof(*p));
 	p->protocol_min = cpu_to_be32(PRO_VERSION_MIN);
 	p->protocol_max = cpu_to_be32(PRO_VERSION_MAX);
+	p->feature_flags = cpu_to_be32(PRO_FEATURES);
 	return conn_send_command(connection, sock, P_CONNECTION_FEATURES, sizeof(*p), NULL, 0);
 }
 
@@ -4741,10 +4747,14 @@ static int drbd_do_features(struct drbd_connection *connection)
 		goto incompat;
 
 	connection->agreed_pro_version = min_t(int, PRO_VERSION_MAX, p->protocol_max);
+	connection->agreed_features = PRO_FEATURES & be32_to_cpu(p->feature_flags);
 
 	drbd_info(connection, "Handshake successful: "
 	     "Agreed network protocol version %d\n", connection->agreed_pro_version);
 
+	drbd_info(connection, "Agreed to%ssupport TRIM on protocol level\n",
+		  connection->agreed_features & FF_TRIM ? " " : " not ");
+
 	return 1;
 
  incompat:
-- 
1.9.1

[Drbd-dev] [PATCH 15/24] drbd: fix a race between start_resync and send_and_submit

[Philipp Reisner]

From: Lars Ellenberg <lars@linbit.com>

In the drbd make request function, specifically in
drbd_send_and_submit(), we decide whether we want to send the actual
write request, or only a "set this block out of sync" information.

We do so based on the current connection state, while holding the req_lock.
The connection state is not supposed to change while holding the req_lock.

But in drbd_start_resync, we did change that state anyways,
while only holding the global_state_lock, which is enough to change
sync-after dependencies (paused vs active resync), but
not good enough to change the connection state.

Fix: in drbd_start_resync, first grab the req_lock to serialize with
drbd_send_and_submit(), before grabbing the global_state_lock
to be able to evaluate the sync-after dependencies.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_worker.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 26338be..34dde10 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1686,11 +1686,15 @@ void drbd_start_resync(struct drbd_device *device, enum drbd_conns side)
 	}
 	clear_bit(B_RS_H_DONE, &device->flags);
 
-	write_lock_irq(&global_state_lock);
+	/* req_lock: serialize with drbd_send_and_submit() and others
+	 * global_state_lock: for stable sync-after dependencies */
+	spin_lock_irq(&device->resource->req_lock);
+	write_lock(&global_state_lock);
 	/* Did some connection breakage or IO error race with us? */
 	if (device->state.conn < C_CONNECTED
 	|| !get_ldev_if_state(device, D_NEGOTIATING)) {
-		write_unlock_irq(&global_state_lock);
+		write_unlock(&global_state_lock);
+		spin_unlock_irq(&device->resource->req_lock);
 		mutex_unlock(device->state_mutex);
 		return;
 	}
@@ -1730,7 +1734,8 @@ void drbd_start_resync(struct drbd_device *device, enum drbd_conns side)
 		}
 		_drbd_pause_after(device);
 	}
-	write_unlock_irq(&global_state_lock);
+	write_unlock(&global_state_lock);
+	spin_unlock_irq(&device->resource->req_lock);
 
 	if (r == SS_SUCCESS) {
 		/* reset rs_last_bcast when a resync or verify is started,
-- 
1.9.1

[Drbd-dev] [PATCH 16/24] drbd: keep max-bio size during detach/attach on disconnected primary

[Philipp Reisner]

From: Lars Ellenberg <lars@linbit.com>

We want to store in persistent meta data what the peer DRBD can handle,
which, due to spreading requests to multiple bios,
may be more than its backing device can handle.

Otherwise, if a disconnected Primary temporarily loses access to its local data
as well, we may accidentally shrink the max-bio setting, portentially causing
already assembled, but not yet processed, application bios to be spuriously
failed due to device limits.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_nl.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 2364b78..a187c5b 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1194,8 +1194,14 @@ void drbd_reconsider_max_bio_size(struct drbd_device *device)
 			peer = DRBD_MAX_BIO_SIZE_P95;  /* drbd 8.3.8 onwards, before 8.4.0 */
 		else
 			peer = DRBD_MAX_BIO_SIZE;
-	}
 
+		/* We may later detach and re-attach on a disconnected Primary.
+		 * Avoid this setting to jump back in that case.
+		 * We want to store what we know the peer DRBD can handle,
+		 * not what the peer IO backend can handle. */
+		if (peer > device->peer_max_bio_size)
+			device->peer_max_bio_size = peer;
+	}
 	new = min(local, peer);
 
 	if (device->state.role == R_PRIMARY && new < now)
-- 
1.9.1

[Drbd-dev] [PATCH 17/24] drbd: add back some fairness to AL transactions

[Philipp Reisner]

From: Lars Ellenberg <lars@linbit.com>

When batching more updates to the activity log into single transactions,
we lost the ability for new requests to force themselves into the active
set: all preparation steps became non-blocking, and if all currently
hot extents keep busy, they could starve out new incoming requests
to cold extents for quite a while.

This can only happen if your IO backend accepts more IO operations per
average DRBD replication round trip time than you have al-extents
configured.

If we have incoming requests to cold extents,
at least do one blocking update per transaction.

In an artificial worst-case workload on SSD with an asynchronous 600 ms
replication link, with al-extents = 7 (the minimum we allow), and
concurrent full resynch, without this patch, some write requests have
been observed to be starved for 40 seconds.
With this patch, application observed a worst case latency of twice the
replication round trip time.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_actlog.c |  3 +--
 drivers/block/drbd/drbd_int.h    |  1 +
 drivers/block/drbd/drbd_req.c    | 20 ++++++++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 8fc5d71..05a1780 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -203,7 +203,7 @@ int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bd
 
 	BUG_ON(!bdev->md_bdev);
 
-	drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
+	dynamic_drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
 	     current->comm, current->pid, __func__,
 	     (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ",
 	     (void*)_RET_IP_ );
@@ -275,7 +275,6 @@ bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval
 	return _al_get(device, first, true);
 }
 
-static
 bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i)
 {
 	/* for bios crossing activity log extent boundaries,
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index d5f39fd..297ba40 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1487,6 +1487,7 @@ extern const char *drbd_conn_str(enum drbd_conns s);
 extern const char *drbd_role_str(enum drbd_role s);
 
 /* drbd_actlog.c */
+extern bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i);
 extern int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i);
 extern void drbd_al_begin_io_commit(struct drbd_device *device, bool delegate);
 extern bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i);
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 7aadd09..99411bf 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1242,6 +1242,7 @@ void do_submit(struct work_struct *ws)
 		if (list_empty(&incoming))
 			break;
 
+skip_fast_path:
 		wait_event(device->al_wait, prepare_al_transaction_nonblock(device, &incoming, &pending));
 		/* Maybe more was queued, while we prepared the transaction?
 		 * Try to stuff them into this transaction as well.
@@ -1280,6 +1281,25 @@ void do_submit(struct work_struct *ws)
 			list_del_init(&req->tl_requests);
 			drbd_send_and_submit(device, req);
 		}
+
+		/* If all currently hot activity log extents are kept busy by
+		 * incoming requests, we still must not totally starve new
+		 * requests to cold extents. In that case, prepare one request
+		 * in blocking mode. */
+		list_for_each_entry_safe(req, tmp, &incoming, tl_requests) {
+			list_del_init(&req->tl_requests);
+			req->rq_state |= RQ_IN_ACT_LOG;
+			if (!drbd_al_begin_io_prepare(device, &req->i)) {
+				/* Corresponding extent was hot after all? */
+				drbd_send_and_submit(device, req);
+			} else {
+				/* Found a request to a cold extent.
+				 * Put on "pending" list,
+				 * and try to cumulate with more. */
+				list_add(&req->tl_requests, &pending);
+				goto skip_fast_path;
+			}
+		}
 	}
 }
 
-- 
1.9.1

[Drbd-dev] [PATCH 18/24] drbd: always implicitly close last epoch when idle

[Philipp Reisner]

From: Lars Ellenberg <lars@linbit.com>

Once our sender thread needs to wait_for_work(),
and actually needs to schedule(), just before we do that,
we already check if it is useful to implicitly close the last epoch.

The condition was too strict: only implicitly close the epoch,
if there have been no new (write) requests at all.

The assumption was that if there were new requests, they would
always be communicated one way or another, and would send necessary
epoch separating barriers explicitly.

This is not always true, e.g. when becoming diskless,
or while explicitly starting a full resync.

The last communicated epoch could stay open for a long time,
locking down corresponding activity log extents.

It is safe to always implicitly send that last barrier, as soon as we
determin that there cannot be more requests in the last communicated
epoch, even if there have been (uncommunicated) new requests in new
epochs meanwhile.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_worker.c | 48 +++++++++++++---------------------------
 1 file changed, 15 insertions(+), 33 deletions(-)

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 34dde10..d8f57b6 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1799,34 +1799,6 @@ void drbd_start_resync(struct drbd_device *device, enum drbd_conns side)
 	mutex_unlock(device->state_mutex);
 }
 
-/* If the resource already closed the current epoch, but we did not
- * (because we have not yet seen new requests), we should send the
- * corresponding barrier now.  Must be checked within the same spinlock
- * that is used to check for new requests. */
-static bool need_to_send_barrier(struct drbd_connection *connection)
-{
-	if (!connection->send.seen_any_write_yet)
-		return false;
-
-	/* Skip barriers that do not contain any writes.
-	 * This may happen during AHEAD mode. */
-	if (!connection->send.current_epoch_writes)
-		return false;
-
-	/* ->req_lock is held when requests are queued on
-	 * connection->sender_work, and put into ->transfer_log.
-	 * It is also held when ->current_tle_nr is increased.
-	 * So either there are already new requests queued,
-	 * and corresponding barriers will be send there.
-	 * Or nothing new is queued yet, so the difference will be 1.
-	 */
-	if (atomic_read(&connection->current_tle_nr) !=
-	    connection->send.current_epoch_nr + 1)
-		return false;
-
-	return true;
-}
-
 static bool dequeue_work_batch(struct drbd_work_queue *queue, struct list_head *work_list)
 {
 	spin_lock_irq(&queue->q_lock);
@@ -1885,12 +1857,22 @@ static void wait_for_work(struct drbd_connection *connection, struct list_head *
 			spin_unlock_irq(&connection->resource->req_lock);
 			break;
 		}
-		send_barrier = need_to_send_barrier(connection);
+
+		/* We found nothing new to do, no to-be-communicated request,
+		 * no other work item.  We may still need to close the last
+		 * epoch.  Next incoming request epoch will be connection ->
+		 * current transfer log epoch number.  If that is different
+		 * from the epoch of the last request we communicated, it is
+		 * safe to send the epoch separating barrier now.
+		 */
+		send_barrier =
+			atomic_read(&connection->current_tle_nr) !=
+			connection->send.current_epoch_nr;
 		spin_unlock_irq(&connection->resource->req_lock);
-		if (send_barrier) {
-			drbd_send_barrier(connection);
-			connection->send.current_epoch_nr++;
-		}
+
+		if (send_barrier)
+			maybe_send_barrier(connection,
+					connection->send.current_epoch_nr + 1);
 		schedule();
 		/* may be woken up for other things but new work, too,
 		 * e.g. if the current epoch got closed.
-- 
1.9.1

[Drbd-dev] [PATCH 19/24] drbd: Fix a hole in the challange-response connection authentication

[Philipp Reisner]

In the implementation as it was, the two peers sent each other
a challenge, and expects the challenge hashed with the shared
secret back.

A attacker could simply wait for the challenge of the peer, and
send the same challenge back. Then it waits for the response, and
sends the same response back.

Prevent this by not accepting a challenge from the peer that is
the same as the challenge sent to the peer.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_receiver.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 3fa3b78..b6c8aaf 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -4846,6 +4846,12 @@ static int drbd_do_auth(struct drbd_connection *connection)
 		goto fail;
 	}
 
+	if (pi.size < CHALLENGE_LEN) {
+		drbd_err(connection, "AuthChallenge payload too small.\n");
+		rv = -1;
+		goto fail;
+	}
+
 	peers_ch = kmalloc(pi.size, GFP_NOIO);
 	if (peers_ch == NULL) {
 		drbd_err(connection, "kmalloc of peers_ch failed\n");
@@ -4859,6 +4865,12 @@ static int drbd_do_auth(struct drbd_connection *connection)
 		goto fail;
 	}
 
+	if (!memcmp(my_challenge, peers_ch, CHALLENGE_LEN)) {
+		drbd_err(connection, "Peer presented the same challenge!\n");
+		rv = -1;
+		goto fail;
+	}
+
 	resp_size = crypto_hash_digestsize(connection->cram_hmac_tfm);
 	response = kmalloc(resp_size, GFP_NOIO);
 	if (response == NULL) {
-- 
1.9.1

[Drbd-dev] [PATCH 20/24] drbd: evaluate disk and network timeout on different requests

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

Just because it is the oldest not yet completed request
does not make it the oldest request waiting for disk.
Or waiting for the peer.

And we completely missed already completed requests
that would still hold references to activity log extents,
waiting only for the barrier ack.

Find two oldest not yet completely processed requests,
one that is still waiting for local completion,
and one that is still waiting for some response from the peer.
These may or may not be the same request object.

Then separately apply the network and disk timeouts, respectively.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_req.c | 47 ++++++++++++++++++++++++++++++-------------
 1 file changed, 33 insertions(+), 14 deletions(-)

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 99411bf..09803d0 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1353,23 +1353,35 @@ int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct
 	return limit;
 }
 
-static struct drbd_request *find_oldest_request(struct drbd_connection *connection)
+static void find_oldest_requests(
+		struct drbd_connection *connection,
+		struct drbd_device *device,
+		struct drbd_request **oldest_req_waiting_for_peer,
+		struct drbd_request **oldest_req_waiting_for_disk)
 {
-	/* Walk the transfer log,
-	 * and find the oldest not yet completed request */
 	struct drbd_request *r;
+	*oldest_req_waiting_for_peer = NULL;
+	*oldest_req_waiting_for_disk = NULL;
 	list_for_each_entry(r, &connection->transfer_log, tl_requests) {
-		if (atomic_read(&r->completion_ref))
-			return r;
+		const unsigned s = r->rq_state;
+		if (!*oldest_req_waiting_for_peer
+		&& ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE)))
+			*oldest_req_waiting_for_peer = r;
+
+		if (!*oldest_req_waiting_for_disk
+		&& (s & RQ_LOCAL_PENDING) && r->device == device)
+			*oldest_req_waiting_for_disk = r;
+
+		if (*oldest_req_waiting_for_peer && *oldest_req_waiting_for_disk)
+			break;
 	}
-	return NULL;
 }
 
 void request_timer_fn(unsigned long data)
 {
 	struct drbd_device *device = (struct drbd_device *) data;
 	struct drbd_connection *connection = first_peer_device(device)->connection;
-	struct drbd_request *req; /* oldest request */
+	struct drbd_request *req_disk, *req_peer; /* oldest request */
 	struct net_conf *nc;
 	unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */
 	unsigned long now;
@@ -1393,8 +1405,8 @@ void request_timer_fn(unsigned long data)
 	now = jiffies;
 
 	spin_lock_irq(&device->resource->req_lock);
-	req = find_oldest_request(connection);
-	if (!req) {
+	find_oldest_requests(connection, device, &req_peer, &req_disk);
+	if (req_peer == NULL && req_disk == NULL) {
 		spin_unlock_irq(&device->resource->req_lock);
 		mod_timer(&device->request_timer, now + et);
 		return;
@@ -1416,19 +1428,26 @@ void request_timer_fn(unsigned long data)
 	 * ~198 days with 250 HZ, we have a window where the timeout would need
 	 * to expire twice (worst case) to become effective. Good enough.
 	 */
-	if (ent && req->rq_state & RQ_NET_PENDING &&
-		 time_after(now, req->start_time + ent) &&
+	if (ent && req_peer &&
+		 time_after(now, req_peer->start_time + ent) &&
 		!time_in_range(now, connection->last_reconnect_jif, connection->last_reconnect_jif + ent)) {
 		drbd_warn(device, "Remote failed to finish a request within ko-count * timeout\n");
 		_drbd_set_state(_NS(device, conn, C_TIMEOUT), CS_VERBOSE | CS_HARD, NULL);
 	}
-	if (dt && req->rq_state & RQ_LOCAL_PENDING && req->device == device &&
-		 time_after(now, req->start_time + dt) &&
+	if (dt && req_disk &&
+		 time_after(now, req_disk->start_time + dt) &&
 		!time_in_range(now, device->last_reattach_jif, device->last_reattach_jif + dt)) {
 		drbd_warn(device, "Local backing device failed to meet the disk-timeout\n");
 		__drbd_chk_io_error(device, DRBD_FORCE_DETACH);
 	}
-	nt = (time_after(now, req->start_time + et) ? now : req->start_time) + et;
+
+	/* Reschedule timer for the nearest not already expired timeout.
+	 * Fallback to now + min(effective network timeout, disk timeout). */
+	ent = (ent && req_peer && time_before(now, req_peer->start_time + ent))
+		? req_peer->start_time + ent : now + et;
+	dt = (dt && req_disk && time_before(now, req_disk->start_time + dt))
+		? req_disk->start_time + dt : now + et;
+	nt = time_before(ent, dt) ? ent : dt;
 	spin_unlock_irq(&connection->resource->req_lock);
 	mod_timer(&device->request_timer, nt);
 }
-- 
1.9.1

[Drbd-dev] [PATCH 21/24] drbd: use blk_set_stacking_limits()

[Philipp Reisner]

...instead directly assigning to q->limits.discard_zeroes_data

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_nl.c | 12 ++++++------
 include/linux/drbd.h         |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index a187c5b..b4fc401 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1114,15 +1114,18 @@ static void drbd_setup_queue_param(struct drbd_device *device, unsigned int max_
 	struct request_queue * const q = device->rq_queue;
 	unsigned int max_hw_sectors = max_bio_size >> 9;
 	unsigned int max_segments = 0;
+	struct request_queue *b = NULL;
 
 	if (get_ldev_if_state(device, D_ATTACHING)) {
-		struct request_queue * const b = device->ldev->backing_bdev->bd_disk->queue;
+		b = device->ldev->backing_bdev->bd_disk->queue;
 
 		max_hw_sectors = min(queue_max_hw_sectors(b), max_bio_size >> 9);
 		rcu_read_lock();
 		max_segments = rcu_dereference(device->ldev->disk_conf)->max_bio_bvecs;
 		rcu_read_unlock();
-		put_ldev(device);
+
+		blk_set_stacking_limits(&q->limits);
+		blk_queue_max_write_same_sectors(q, 0);
 	}
 
 	blk_queue_logical_block_size(q, 512);
@@ -1131,14 +1134,11 @@ static void drbd_setup_queue_param(struct drbd_device *device, unsigned int max_
 	blk_queue_max_segments(q, max_segments ? max_segments : BLK_MAX_SEGMENTS);
 	blk_queue_segment_boundary(q, PAGE_CACHE_SIZE-1);
 
-	if (get_ldev_if_state(device, D_ATTACHING)) {
-		struct request_queue * const b = device->ldev->backing_bdev->bd_disk->queue;
+	if (b) {
 		struct drbd_connection *connection = first_peer_device(device)->connection;
 
 		if (blk_queue_discard(b) &&
 		    (connection->cstate < C_CONNECTED || connection->agreed_features & FF_TRIM)) {
-			/* inherit from backing queue */
-			q->limits.discard_zeroes_data = 1;
 			/* For now, don't allow more than one activity log extent worth of data
 			 * to be discarded in one go. We may need to rework drbd_al_begin_io()
 			 * to allow for even larger discard ranges */
diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index 3dbe9bd..fffd4b8 100644
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -52,7 +52,7 @@
 #endif
 
 extern const char *drbd_buildtag(void);
-#define REL_VERSION "8.4.3"
+#define REL_VERSION "8.4.4"
 #define API_VERSION 1
 #define PRO_VERSION_MIN 86
 #define PRO_VERSION_MAX 101
-- 
1.9.1

[Drbd-dev] [PATCH 22/24] drbd: Test cstate while holding req_lock

[Philipp Reisner]

In case a connection transitions into C_TIMEOUT within the timer
function (request_timer_fn()) we need to make sure that the receiver
thread (potentially running on a different CPU) sees the updated
cstate later on.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_nl.c | 3 ++-
 include/linux/drbd.h         | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index b4fc401..f4d3aff 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -442,12 +442,13 @@ bool conn_try_outdate_peer(struct drbd_connection *connection)
 	char *ex_to_string;
 	int r;
 
+	spin_lock_irq(&connection->resource->req_lock);
 	if (connection->cstate >= C_WF_REPORT_PARAMS) {
 		drbd_err(connection, "Expected cstate < C_WF_REPORT_PARAMS\n");
+		spin_unlock_irq(&connection->resource->req_lock);
 		return false;
 	}
 
-	spin_lock_irq(&connection->resource->req_lock);
 	connect_cnt = connection->connect_cnt;
 	spin_unlock_irq(&connection->resource->req_lock);
 
diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index fffd4b8..3dbe9bd 100644
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -52,7 +52,7 @@
 #endif
 
 extern const char *drbd_buildtag(void);
-#define REL_VERSION "8.4.4"
+#define REL_VERSION "8.4.3"
 #define API_VERSION 1
 #define PRO_VERSION_MIN 86
 #define PRO_VERSION_MAX 101
-- 
1.9.1

[Drbd-dev] [PATCH 23/24] drbd: Allow attaching of a newly created device to any backing device

[Philipp Reisner]

A newly created device was never exposed before, i.e. has a
exposed_data_uuid of 0. Then it is valid to attach to any current_uuid
of a backing device (of course also to a newly created one (4))

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_nl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index f4d3aff..1b35c45 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1662,7 +1662,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	if (device->state.conn < C_CONNECTED &&
-	    device->state.role == R_PRIMARY &&
+	    device->state.role == R_PRIMARY && device->ed_uuid &&
 	    (device->ed_uuid & ~((u64)1)) != (nbc->md.uuid[UI_CURRENT] & ~((u64)1))) {
 		drbd_err(device, "Can only attach to data with current UUID=%016llX\n",
 		    (unsigned long long)device->ed_uuid);
-- 
1.9.1

[Drbd-dev] [PATCH 24/24] drbd: use list_first_entry_or_null in first_peer_device/first_connection

[Philipp Reisner]

From: Lars Ellenberg <lars.ellenberg@linbit.com>

If there are no peer_devices or connections, I'd rather have NULL
than some "arbitrary" address pretending to point to a struct.

Helps to avoid hard to debug symptoms, in case we ever try to use
and dereference a drbd_connection or drbd_peer_device
where we in fact don't have any connection at all.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
 drivers/block/drbd/drbd_int.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 297ba40..a76ceb3 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -853,7 +853,7 @@ static inline struct drbd_device *minor_to_device(unsigned int minor)
 
 static inline struct drbd_peer_device *first_peer_device(struct drbd_device *device)
 {
-	return list_first_entry(&device->peer_devices, struct drbd_peer_device, peer_devices);
+	return list_first_entry_or_null(&device->peer_devices, struct drbd_peer_device, peer_devices);
 }
 
 #define for_each_resource(resource, _resources) \
@@ -2222,7 +2222,7 @@ static inline void drbd_md_flush(struct drbd_device *device)
 
 static inline struct drbd_connection *first_connection(struct drbd_resource *resource)
 {
-	return list_first_entry(&resource->connections,
+	return list_first_entry_or_null(&resource->connections,
 				struct drbd_connection, connections);
 }
 
-- 
1.9.1

Re: [Drbd-dev] [PATCH 00/24] RFC: DRBD Fixes and REQ_DISCARD support

[Jens Axboe]

On 04/28/2014 10:43 AM, Philipp Reisner wrote:
> This patch series contains these new features for DRBD:
>  * Support for REQ_DISCARD
>  * Allow parallel promote/demote
>  * Allow online changing of al-stripes and al-stripe-size with the
>    resize command
> 
> and contains fixes for these issues:
>  * fix potential deadlock when concurrently fencing and establishing a connection
>  * fix potential distributed deadlock during verify or resync
>  * fix decoding of bitmap vli rle for device sizes > 64 TB
>  * fix for deadlock when using automatic split-brain-recovery
>  * only fail empty flushes if no good data is reachable
>  * avoid to shrink max_bio_size due to peer re-configuration
>  * fix resume-io after reconnect with broken fence-peer handler
>  * fix too large bursts for very slow resync rates
>  * don't let application IO throttle resync to a stall
>  * Fixed a hole in the challenge-response implementation
>  * Fixed a theoretical IO deadlock (Only triggers with unusual small AL i.e. 7)
>  * Fixed attaching to disks with fixed size external meta-data
>    (This regressions was introduced with 8.4.3)
>  * Fixed a crash when the connection broke at a very exact point in
>    time while a graceful disconnect executes
> 
> Lars Ellenberg (15):
>   drbd: fix stalled resync detection in /proc/drbd
>   drbd: resync: fix too large bursts for very slow rates
>   drbd: fix potential distributed deadlock during verify or resync
>   drbd: don't let application IO pre-empt resync too often
>   drbd: perpare for genetlink parallel_ops
>   drbd: allow parallel promote/demote actions
>   drbd: prepare receiving side for REQ_DISCARD
>   drbd: prepare sending side for REQ_DISCARD
>   drbd: Enable QUEUE_FLAG_DISCARD only if the peer can recieve P_TRIM
>   drbd: fix a race between start_resync and send_and_submit
>   drbd: keep max-bio size during detach/attach on disconnected primary
>   drbd: add back some fairness to AL transactions
>   drbd: always implicitly close last epoch when idle
>   drbd: evaluate disk and network timeout on different requests
>   drbd: use list_first_entry_or_null in first_peer_device/first_connection
> 
> Philipp Reisner (9):
>   drbd: Break a deadlock while concurrent fencing and establishing a connection
>   drbd: Leave IO suspended if the fence handler find the peer primary
>   drbd: Remove drbd_wrappers.h
>   drbd: Allow online layout change of AL while peer is not connected
>   drbd: Do not BUG() when connection breaks in a special way
>   drbd: Fix a hole in the challange-response connection authentication
>   drbd: use blk_set_stacking_limits()
>   drbd: Test cstate while holding req_lock
>   drbd: Allow attaching of a newly created device to any backing device
> 
>  drivers/block/drbd/drbd_actlog.c   |  23 +-
>  drivers/block/drbd/drbd_int.h      |  92 ++++++-
>  drivers/block/drbd/drbd_main.c     |  28 ++-
>  drivers/block/drbd/drbd_nl.c       | 485 ++++++++++++++++++++++---------------
>  drivers/block/drbd/drbd_nla.c      |   1 -
>  drivers/block/drbd/drbd_proc.c     |   2 +-
>  drivers/block/drbd/drbd_protocol.h |  12 +
>  drivers/block/drbd/drbd_receiver.c | 196 ++++++++++-----
>  drivers/block/drbd/drbd_req.c      |  74 ++++--
>  drivers/block/drbd/drbd_req.h      |   6 +-
>  drivers/block/drbd/drbd_state.c    |  38 +--
>  drivers/block/drbd/drbd_worker.c   | 107 ++++----
>  drivers/block/drbd/drbd_wrappers.h |  54 -----
>  13 files changed, 701 insertions(+), 417 deletions(-)
>  delete mode 100644 drivers/block/drbd/drbd_wrappers.h

Added for 3.16, thanks.


-- 
Jens Axboe

Re: [PATCH 00/24] RFC: DRBD Fixes and REQ_DISCARD support

[Jens Axboe]

On 04/28/2014 10:43 AM, Philipp Reisner wrote:
> This patch series contains these new features for DRBD:
>  * Support for REQ_DISCARD
>  * Allow parallel promote/demote
>  * Allow online changing of al-stripes and al-stripe-size with the
>    resize command
> 
> and contains fixes for these issues:
>  * fix potential deadlock when concurrently fencing and establishing a connection
>  * fix potential distributed deadlock during verify or resync
>  * fix decoding of bitmap vli rle for device sizes > 64 TB
>  * fix for deadlock when using automatic split-brain-recovery
>  * only fail empty flushes if no good data is reachable
>  * avoid to shrink max_bio_size due to peer re-configuration
>  * fix resume-io after reconnect with broken fence-peer handler
>  * fix too large bursts for very slow resync rates
>  * don't let application IO throttle resync to a stall
>  * Fixed a hole in the challenge-response implementation
>  * Fixed a theoretical IO deadlock (Only triggers with unusual small AL i.e. 7)
>  * Fixed attaching to disks with fixed size external meta-data
>    (This regressions was introduced with 8.4.3)
>  * Fixed a crash when the connection broke at a very exact point in
>    time while a graceful disconnect executes
> 
> Lars Ellenberg (15):
>   drbd: fix stalled resync detection in /proc/drbd
>   drbd: resync: fix too large bursts for very slow rates
>   drbd: fix potential distributed deadlock during verify or resync
>   drbd: don't let application IO pre-empt resync too often
>   drbd: perpare for genetlink parallel_ops
>   drbd: allow parallel promote/demote actions
>   drbd: prepare receiving side for REQ_DISCARD
>   drbd: prepare sending side for REQ_DISCARD
>   drbd: Enable QUEUE_FLAG_DISCARD only if the peer can recieve P_TRIM
>   drbd: fix a race between start_resync and send_and_submit
>   drbd: keep max-bio size during detach/attach on disconnected primary
>   drbd: add back some fairness to AL transactions
>   drbd: always implicitly close last epoch when idle
>   drbd: evaluate disk and network timeout on different requests
>   drbd: use list_first_entry_or_null in first_peer_device/first_connection
> 
> Philipp Reisner (9):
>   drbd: Break a deadlock while concurrent fencing and establishing a connection
>   drbd: Leave IO suspended if the fence handler find the peer primary
>   drbd: Remove drbd_wrappers.h
>   drbd: Allow online layout change of AL while peer is not connected
>   drbd: Do not BUG() when connection breaks in a special way
>   drbd: Fix a hole in the challange-response connection authentication
>   drbd: use blk_set_stacking_limits()
>   drbd: Test cstate while holding req_lock
>   drbd: Allow attaching of a newly created device to any backing device
> 
>  drivers/block/drbd/drbd_actlog.c   |  23 +-
>  drivers/block/drbd/drbd_int.h      |  92 ++++++-
>  drivers/block/drbd/drbd_main.c     |  28 ++-
>  drivers/block/drbd/drbd_nl.c       | 485 ++++++++++++++++++++++---------------
>  drivers/block/drbd/drbd_nla.c      |   1 -
>  drivers/block/drbd/drbd_proc.c     |   2 +-
>  drivers/block/drbd/drbd_protocol.h |  12 +
>  drivers/block/drbd/drbd_receiver.c | 196 ++++++++++-----
>  drivers/block/drbd/drbd_req.c      |  74 ++++--
>  drivers/block/drbd/drbd_req.h      |   6 +-
>  drivers/block/drbd/drbd_state.c    |  38 +--
>  drivers/block/drbd/drbd_worker.c   | 107 ++++----
>  drivers/block/drbd/drbd_wrappers.h |  54 -----
>  13 files changed, 701 insertions(+), 417 deletions(-)
>  delete mode 100644 drivers/block/drbd/drbd_wrappers.h

Added for 3.16, thanks.


-- 
Jens Axboe