39 files changed, 2932 insertions, 1311 deletions

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index bda1497add4c..51bf5155ee75 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -290,6 +290,7 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
         unsigned long start_time;
         ssize_t ret = 0;
         int writing = 0;
+        int at_head = 0;
         struct request *rq;
         char sense[SCSI_SENSE_BUFFERSIZE];
         struct bio *bio;
@@ -313,6 +314,8 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
                 case SG_DXFER_FROM_DEV:
                         break;
                 }
+        if (hdr->flags & SG_FLAG_Q_AT_HEAD)
+                at_head = 1;
 
         rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
         if (!rq)
@@ -369,7 +372,7 @@ static int sg_io(struct request_queue *q, struct gendisk *bd_disk,
          * (if he doesn't check that is his problem).
          * N.B. a non-zero SCSI status is _not_ necessarily an error.
          */
-        blk_execute_rq(q, bd_disk, rq, 0);
+        blk_execute_rq(q, bd_disk, rq, at_head);
 
         hdr->duration = jiffies_to_msecs(jiffies - start_time);
 
diff --git a/drivers/block/drbd/Makefile b/drivers/block/drbd/Makefile
index 8b450338075e..4464e353c1e8 100644
--- a/drivers/block/drbd/Makefile
+++ b/drivers/block/drbd/Makefile
@@ -3,5 +3,6 @@ drbd-y += drbd_worker.o drbd_receiver.o drbd_req.o drbd_actlog.o
 drbd-y += drbd_main.o drbd_strings.o drbd_nl.o
 drbd-y += drbd_interval.o drbd_state.o
 drbd-y += drbd_nla.o
+drbd-$(CONFIG_DEBUG_FS) += drbd_debugfs.o
 
 obj-$(CONFIG_BLK_DEV_DRBD)     += drbd.o
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 05a1780ffa85..d26a3fa63688 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -92,34 +92,26 @@ struct __packed al_transaction_on_disk {
         __be32  context[AL_CONTEXT_PER_TRANSACTION];
 };
 
-struct update_odbm_work {
-        struct drbd_work w;
-        struct drbd_device *device;
-        unsigned int enr;
-};
-
-struct update_al_work {
-        struct drbd_work w;
-        struct drbd_device *device;
-        struct completion event;
-        int err;
-};
-
-
-void *drbd_md_get_buffer(struct drbd_device *device)
+void *drbd_md_get_buffer(struct drbd_device *device, const char *intent)
 {
         int r;
 
         wait_event(device->misc_wait,
-                   (r = atomic_cmpxchg(&device->md_io_in_use, 0, 1)) == 0 ||
+                   (r = atomic_cmpxchg(&device->md_io.in_use, 0, 1)) == 0 ||
                    device->state.disk <= D_FAILED);
 
-        return r ? NULL : page_address(device->md_io_page);
+        if (r)
+                return NULL;
+
+        device->md_io.current_use = intent;
+        device->md_io.start_jif = jiffies;
+        device->md_io.submit_jif = device->md_io.start_jif - 1;
+        return page_address(device->md_io.page);
 }
 
 void drbd_md_put_buffer(struct drbd_device *device)
 {
-        if (atomic_dec_and_test(&device->md_io_in_use))
+        if (atomic_dec_and_test(&device->md_io.in_use))
                 wake_up(&device->misc_wait);
 }
 
@@ -145,10 +137,11 @@ void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_b
 
 static int _drbd_md_sync_page_io(struct drbd_device *device,
                                  struct drbd_backing_dev *bdev,
-                                 struct page *page, sector_t sector,
-                                 int rw, int size)
+                                 sector_t sector, int rw)
 {
         struct bio *bio;
+        /* we do all our meta data IO in aligned 4k blocks. */
+        const int size = 4096;
         int err;
 
         device->md_io.done = 0;
@@ -156,15 +149,15 @@ static int _drbd_md_sync_page_io(struct drbd_device *device,
 
         if ((rw & WRITE) && !test_bit(MD_NO_FUA, &device->flags))
                 rw |= REQ_FUA | REQ_FLUSH;
-        rw |= REQ_SYNC;
+        rw |= REQ_SYNC | REQ_NOIDLE;
 
         bio = bio_alloc_drbd(GFP_NOIO);
         bio->bi_bdev = bdev->md_bdev;
         bio->bi_iter.bi_sector = sector;
         err = -EIO;
-        if (bio_add_page(bio, page, size, 0) != size)
+        if (bio_add_page(bio, device->md_io.page, size, 0) != size)
                 goto out;
-        bio->bi_private = &device->md_io;
+        bio->bi_private = device;