Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block: (34 commits)
  cfq-iosched: Fix the incorrect timeslice accounting with forced_dispatch
  loop: Update mtime when writing using aops
  block: expose the statistics in blkio.time and blkio.sectors for the root cgroup
  backing-dev: Handle class_create() failure
  Block: Fix block/elevator.c elevator_get() off-by-one error
  drbd: lc_element_by_index() never returns NULL
  cciss: unlock on error path
  cfq-iosched: Do not merge queues of BE and IDLE classes
  cfq-iosched: Add additional blktrace log messages in CFQ for easier debugging
  i2o: Remove the dangerous kobj_to_i2o_device macro
  block: remove 16 bytes of padding from struct request on 64bits
  cfq-iosched: fix a kbuild regression
  block: make CONFIG_BLK_CGROUP visible
  Remove GENHD_FL_DRIVERFS
  block: Export max number of segments and max segment size in sysfs
  block: Finalize conversion of block limits functions
  block: Fix overrun in lcm() and move it to lib
  vfs: improve writeback_inodes_wb()
  paride: fix off-by-one test
  drbd: fix al-to-on-disk-bitmap for 4k logical_block_size
  ...

34 files changed, 475 insertions, 178 deletions

diff --git a/Documentation/DocBook/tracepoint.tmpl b/Documentation/DocBook/tracepoint.tmpl
index 8bca1d5cec0..e8473eae2a2 100644
--- a/Documentation/DocBook/tracepoint.tmpl
+++ b/Documentation/DocBook/tracepoint.tmpl
@@ -16,6 +16,15 @@
      </address>
     </affiliation>
    </author>
+   <author>
+    <firstname>William</firstname>
+    <surname>Cohen</surname>
+    <affiliation>
+     <address>
+      <email>wcohen@redhat.com</email>
+     </address>
+    </affiliation>
+   </author>
   </authorgroup>
 
   <legalnotice>
@@ -91,4 +100,8 @@
 !Iinclude/trace/events/signal.h
   </chapter>
 
+  <chapter id="block">
+   <title>Block IO</title>
+!Iinclude/trace/events/block.h
+  </chapter>
 </book>
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 6fab97ea7e6..508b5b2b028 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -1162,8 +1162,8 @@ where a driver received a request ala this before:
 
 As mentioned, there is no virtual mapping of a bio. For DMA, this is
 not a problem as the driver probably never will need a virtual mapping.
-Instead it needs a bus mapping (pci_map_page for a single segment or
-use blk_rq_map_sg for scatter gather) to be able to ship it to the driver. For
+Instead it needs a bus mapping (dma_map_page for a single segment or
+use dma_map_sg for scatter gather) to be able to ship it to the driver. For
 PIO drivers (or drivers that need to revert to PIO transfer once in a
 while (IDE for example)), where the CPU is doing the actual data
 transfer a virtual mapping is needed. If the driver supports highmem I/O,
diff --git a/block/Kconfig b/block/Kconfig
index 62a5921321c..f9e89f4d94b 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -78,8 +78,9 @@ config BLK_DEV_INTEGRITY
         Protection.  If in doubt, say N.
 
 config BLK_CGROUP
-        tristate
+        tristate "Block cgroup support"
         depends on CGROUPS
+        depends on CFQ_GROUP_IOSCHED
         default n
         ---help---
         Generic block IO controller cgroup interface. This is the common
diff --git a/block/blk-settings.c b/block/blk-settings.c
index d9a9db5f0a2..f5ed5a1187b 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -8,6 +8,7 @@
 #include <linux/blkdev.h>
 #include <linux/bootmem.h>      /* for max_pfn/max_low_pfn */
 #include <linux/gcd.h>
+#include <linux/lcm.h>
 #include <linux/jiffies.h>
 #include <linux/gfp.h>
 
@@ -462,16 +463,6 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
 }
 EXPORT_SYMBOL(blk_queue_stack_limits);
 
-static unsigned int lcm(unsigned int a, unsigned int b)
-{
-        if (a && b)
-                return (a * b) / gcd(a, b);
-        else if (b)
-                return b;
-
-        return a;
-}
-
 /**
  * blk_stack_limits - adjust queue_limits for stacked devices
  * @t:  the stacking driver limits (top device)
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index c2b821fa324..306759bbdf1 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -107,6 +107,19 @@ static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
         return queue_var_show(max_sectors_kb, (page));
 }
 
+static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
+{
+        return queue_var_show(queue_max_segments(q), (page));
+}
+
+static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
+{
+        if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
+                return queue_var_show(queue_max_segment_size(q), (page));
+
+        return queue_var_show(PAGE_CACHE_SIZE, (page));
+}
+
 static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
 {
         return queue_var_show(queue_logical_block_size(q), page);
@@ -281,6 +294,16 @@ static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
         .show = queue_max_hw_sectors_show,
 };
 
+static struct queue_sysfs_entry queue_max_segments_entry = {
+        .attr = {.name = "max_segments", .mode = S_IRUGO },
+        .show = queue_max_segments_show,
+};
+
+static struct queue_sysfs_entry queue_max_segment_size_entry = {
+        .attr = {.name = "max_segment_size", .mode = S_IRUGO },
+        .show = queue_max_segment_size_show,
+};
+
 static struct queue_sysfs_entry queue_iosched_entry = {
         .attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
         .show = elv_iosched_show,
@@ -356,6 +379,8 @@ static struct attribute *default_attrs[] = {
         &queue_ra_entry.attr,
         &queue_max_hw_sectors_entry.attr,
         &queue_max_sectors_entry.attr,
+        &queue_max_segments_entry.attr,
+        &queue_max_segment_size_entry.attr,
         &queue_iosched_entry.attr,
         &queue_hw_sector_size_entry.attr,
         &queue_logical_block_size_entry.attr,
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index fc98a48554f..838834be115 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -48,6 +48,7 @@ static const int cfq_hist_divisor = 4;
 #define CFQ_SERVICE_SHIFT       12
 
 #define CFQQ_SEEK_THR           (sector_t)(8 * 100)
+#define CFQQ_CLOSE_THR          (sector_t)(8 * 1024)
 #define CFQQ_SECT_THR_NONROT    (sector_t)(2 * 32)
 #define CFQQ_SEEKY(cfqq)        (hweight32(cfqq->seek_history) > 32/8)
 
@@ -948,6 +949,11 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
         unsigned int major, minor;
 
         cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
+        if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
+                sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+                cfqg->blkg.dev = MKDEV(major, minor);
+                goto done;
+        }
         if (cfqg || !create)
                 goto done;
 
@@ -1518,7 +1524,8 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
                                    struct cfq_queue *cfqq)
 {
         if (cfqq) {
-                cfq_log_cfqq(cfqd, cfqq, "set_active");
+                cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d",
+                                cfqd->serving_prio, cfqd->serving_type);
                 cfqq->slice_start = 0;
                 cfqq->dispatch_start = jiffies;
                 cfqq->allocated_slice = 0;
@@ -1661,9 +1668,9 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
 }
 
 static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-                               struct request *rq, bool for_preempt)
+                               struct request *rq)
 {
-        return cfq_dist_from_last(cfqd, rq) <= CFQQ_SEEK_THR;
+        return cfq_dist_from_last(cfqd, rq) <= CFQQ_CLOSE_THR;
 }
 
 static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
@@ -1690,7 +1697,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
          * will contain the closest sector.
          */
         __cfqq = rb_entry(parent, struct cfq_queue, p_node);
-        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
+        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
                 return __cfqq;
 
         if (blk_rq_pos(__cfqq->next_rq) < sector)
@@ -1701,7 +1708,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
                 return NULL;
 
         __cfqq = rb_entry(node, struct cfq_queue, p_node);
-        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
+        if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
                 return __cfqq;
 
         return NULL;
@@ -1722,6 +1729,8 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
 {
         struct cfq_queue *cfqq;
 
+        if (cfq_class_idle(cur_cfqq))
+                return NULL;
         if (!cfq_cfqq_sync(cur_cfqq))
                 return NULL;
         if (CFQQ_SEEKY(cur_cfqq))
@@ -1788,7 +1797,11 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
          * Otherwise, we do only if they are the last ones
          * in their service tree.
          */
-        return service_tree->count == 1 && cfq_cfqq_sync(cfqq);
+        if (service_tree->count == 1 && cfq_cfqq_sync(cfqq))
+                return 1;
+        cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d",
+                        service_tree->count);
+        return 0;
 }
 
 static void cfq_arm_slice_timer(struct cfq_data *cfqd)
@@ -1833,8 +1846,11 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
          * time slice.
          */
         if (sample_valid(cic->ttime_samples) &&
-            (cfqq->slice_end - jiffies < cic->ttime_mean))
+            (cfqq->slice_end - jiffies < cic->ttime_mean)) {
+                cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d",
+                                cic->ttime_mean);
                 return;
+        }
 
         cfq_mark_cfqq_wait_request(cfqq);
 
@@ -2042,6 +2058,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
                 slice = max(slice, 2 * cfqd->cfq_slice_idle);
 
         slice = max_t(unsigned, slice, CFQ_MIN_TT);
+        cfq_log(cfqd, "workload slice:%d", slice);
         cfqd->workload_expires = jiffies + slice;
         cfqd->noidle_tree_requires_idle = false;
 }
@@ -2189,10 +2206,13 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
         struct cfq_queue *cfqq;
         int dispatched = 0;
 
-        while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL)
+        /* Expire the timeslice of the current active queue first */
+        cfq_slice_expired(cfqd, 0);
+        while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL) {
+                __cfq_set_active_queue(cfqd, cfqq);
                 dispatched += __cfq_forced_dispatch_cfqq(cfqq);
+        }
 
-        cfq_slice_expired(cfqd, 0);
         BUG_ON(cfqd->busy_queues);
 
         cfq_log(cfqd, "forced_dispatch=%d", dispatched);
@@ -3104,7 +3124,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
          * if this request is as-good as one we would expect from the
          * current cfqq, let it preempt
          */
-        if (cfq_rq_close(cfqd, cfqq, rq, true))
+        if (cfq_rq_close(cfqd, cfqq, rq))
                 return true;
 
         return false;
@@ -3308,6 +3328,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
                 if (cfq_should_wait_busy(cfqd, cfqq)) {
                         cfqq->slice_end = jiffies + cfqd->cfq_slice_idle;
                         cfq_mark_cfqq_wait_busy(cfqq);
+                        cfq_log_cfqq(cfqd, cfqq, "will busy wait");
                 }
 
                 /*
diff --git a/block/elevator.c b/block/elevator.c
index df75676f667..76e3702d538 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -154,7 +154,7 @@ static struct elevator_type *elevator_get(const char *name)
 
                 spin_unlock(&elv_list_lock);
 
-                sprintf(elv, "%s-iosched", name);
+                snprintf(elv, sizeof(elv), "%s-iosched", name);
 
                 request_module("%s", elv);
                 spin_lock(&elv_list_lock);
diff --git a/drivers/block/DAC960.c b/drivers/block/DAC960.c
index 459f1bc25a7..c5f22bb0a48 100644
--- a/drivers/block/DAC960.c
+++ b/drivers/block/DAC960.c
@@ -2533,7 +2533,6 @@ static bool DAC960_RegisterBlockDevice(DAC960_Controller_T *Controller)
         Controller->RequestQueue[n] = RequestQueue;
         blk_queue_bounce_limit(RequestQueue, Controller->BounceBufferLimit);
         RequestQueue->queuedata = Controller;
-        blk_queue_max_hw_segments(RequestQueue, Controller->DriverScatterGatherLimit);
         blk_queue_max_segments(RequestQueue, Controller->DriverScatterGatherLimit);
         blk_queue_max_hw_sectors(RequestQueue, Controller->MaxBlocksPerCommand);
         disk->queue = RequestQueue;
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 17956ff6a08..df018990c42 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -536,7 +536,9 @@ static void atodb_endio(struct bio *bio, int error)
         put_ldev(mdev);
 }
 
+/* sector to word */
 #define S2W(s)  ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL))
+
 /* activity log to on disk bitmap -- prepare bio unless that sector
  * is already covered by previously prepared bios */
 static int atodb_prepare_unless_covered(struct drbd_conf *mdev,
@@ -546,13 +548,20 @@ static int atodb_prepare_unless_covered(struct drbd_conf *mdev,
 {
         struct bio *bio;
         struct page *page;
-        sector_t on_disk_sector = enr + mdev->ldev->md.md_offset
-                                      + mdev->ldev->md.bm_offset;
+        sector_t on_disk_sector;
         unsigned int page_offset = PAGE_SIZE;
         int offset;
         int i = 0;
         int err = -ENOMEM;
 
+        /* We always write aligned, full 4k blocks,
+         * so we can ignore the logical_block_size (for now) */
+        enr &= ~7U;
+        on_disk_sector = enr + mdev->ldev->md.md_offset
+                             + mdev->ldev->md.bm_offset;
+
+        D_ASSERT(!(on_disk_sector & 7U));
+
         /* Check if that enr is already covered by an already created bio.
          * Caution, bios[] is not NULL terminated,
          * but only initialized to all NULL.
@@ -588,7 +597,7 @@ static int atodb_prepare_unless_covered(struct drbd_conf *mdev,
 
         offset = S2W(enr);
         drbd_bm_get_lel(mdev, offset,
-                        min_t(size_t, S2W(1), drbd_bm_words(mdev) - offset),
+                        min_t(size_t, S2W(8), drbd_bm_words(mdev) - offset),
                         kmap(page) + page_offset);
         kunmap(page);
 
@@ -597,7 +606,7 @@ static int atodb_prepare_unless_covered(struct drbd_conf *mdev,
         bio->bi_bdev = mdev->ldev->md_bdev;
         bio->bi_sector = on_disk_sector;
 
-        if (bio_add_page(bio, page, MD_SECTOR_SIZE, page_offset) != MD_SECTOR_SIZE)
+        if (bio_add_page(bio, page, 4096, page_offset) != 4096)
                 goto out_put_page;
 
         atomic_inc(&wc->count);
@@ -1327,7 +1336,7 @@ int drbd_rs_del_all(struct drbd_conf *mdev)
                 /* ok, ->resync is there. */
                 for (i = 0; i < mdev->resync->nr_elements; i++) {
                         e = lc_element_by_index(mdev->resync, i);
-                        bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
+                        bm_ext = lc_entry(e, struct bm_extent, lce);
                         if (bm_ext->lce.lc_number == LC_FREE)
                                 continue;
                         if (bm_ext->lce.lc_number == mdev->resync_wenr) {
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 3d6f3d98894..3390716898d 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -67,7 +67,7 @@ struct drbd_bitmap {
         size_t   bm_words;
         size_t   bm_number_of_pages;
         sector_t bm_dev_capacity;
-        struct semaphore bm_change; /* serializes resize operations */
+        struct mutex bm_change; /* serializes resize operations */
 
         atomic_t bm_async_io;
         wait_queue_head_t bm_io_wait;
@@ -115,7 +115,7 @@ void drbd_bm_lock(struct drbd_conf *mdev, char *why)
                 return;
         }
 
-        trylock_failed = down_trylock(&b->bm_change);
+        trylock_failed = !mutex_trylock(&b->bm_change);
 
         if (trylock_failed) {
                 dev_warn(DEV, "%s going to '%s' but bitmap already locked for '%s' by %s\n",
@@ -126,7 +126,7 @@ void drbd_bm_lock(struct drbd_conf *mdev, char *why)
                     b->bm_task == mdev->receiver.task ? "receiver" :
                     b->bm_task == mdev->asender.task  ? "asender"  :
                     b->bm_task == mdev->worker.task   ? "worker"   : "?");
-                down(&b->bm_change);
+                mutex_lock(&b->bm_change);
         }
         if (__test_and_set_bit(BM_LOCKED, &b->bm_flags))
                 dev_err(DEV, "FIXME bitmap already locked in bm_lock\n");
@@ -148,7 +148,7 @@ void drbd_bm_unlock(struct drbd_conf *mdev)
 
         b->bm_why  = NULL;
         b->bm_task = NULL;
-        up(&b->bm_change);
+        mutex_unlock(&b->bm_change);
 }
 
 /* word offset to long pointer */
@@ -296,7 +296,7 @@ int drbd_bm_init(struct drbd_conf *mdev)
         if (!b)
                 return -ENOMEM;
         spin_lock_init(&b->bm_lock);
-        init_MUTEX(&b->bm_change);
+        mutex_init(&b->bm_change);
         init_waitqueue_head(&b->bm_io_wait);
 
         mdev->bitmap = b;
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index d9301e861d9..e5e86a78182 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -261,6 +261,9 @@ static inline const char *cmdname(enum drbd_packets cmd)
                 [P_OV_REQUEST]          = "OVRequest",
                 [P_OV_REPLY]            = "OVReply",
                 [P_OV_RESULT]           = "OVResult",
+                [P_CSUM_RS_REQUEST]     = "CsumRSRequest",
+                [P_RS_IS_IN_SYNC]       = "CsumRSIsInSync",
+                [P_COMPRESSED_BITMAP]   = "CBitmap",
                 [P_MAX_CMD]             = NULL,
         };
 
@@ -443,13 +446,18 @@ struct p_rs_param_89 {
         char csums_alg[SHARED_SECRET_MAX];
 } __packed;
 
+enum drbd_conn_flags {
+        CF_WANT_LOSE = 1,
+        CF_DRY_RUN = 2,
+};
+
 struct p_protocol {
         struct p_header head;
         u32 protocol;
         u32 after_sb_0p;
         u32 after_sb_1p;
         u32 after_sb_2p;
-        u32 want_lose;
+        u32 conn_flags;
         u32 two_primaries;
 
               /* Since protocol version 87 and higher. */
@@ -791,6 +799,8 @@ enum {
                                  * while this is set. */
         RESIZE_PENDING,         /* Size change detected locally, waiting for the response from
                                  * the peer, if it changed there as well. */
+        CONN_DRY_RUN,           /* Expect disconnect after resync handshake. */
+        GOT_PING_ACK,           /* set when we receive a ping_ack packet, misc wait gets woken */
 };
 
 struct drbd_bitmap; /* opaque for drbd_conf */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index ab871e00ffc..67e0fc54224 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1668,7 +1668,7 @@ int drbd_send_sync_param(struct drbd_conf *mdev, struct syncer_conf *sc)
 int drbd_send_protocol(struct drbd_conf *mdev)
 {
         struct p_protocol *p;
-        int size, rv;
+        int size, cf, rv;
 
         size = sizeof(struct p_protocol);
 
@@ -1685,9 +1685,21 @@ int drbd_send_protocol(struct drbd_conf *mdev)
         p->after_sb_0p   = cpu_to_be32(mdev->net_conf->after_sb_0p);
         p->after_sb_1p   = cpu_to_be32(mdev->net_conf->after_sb_1p);
         p->after_sb_2p   = cpu_to_be32(mdev->net_conf->after_sb_2p);
-        p->want_lose     = cpu_to_be32(mdev->net_conf->want_lose);
         p->two_primaries = cpu_to_be32(mdev->net_conf->two_primaries);
 
+        cf = 0;
+        if (mdev->net_conf->want_lose)
+                cf |= CF_WANT_LOSE;
+        if (mdev->net_conf->dry_run) {
+                if (mdev->agreed_pro_version >= 92)
+                        cf |= CF_DRY_RUN;
+                else {
+                        dev_err(DEV, "--dry-run is not supported by peer");
+                        return 0;
+                }
+        }
+        p->conn_flags    = cpu_to_be32(cf);
+
         if (mdev->agreed_pro_version >= 87)
                 strcpy(p->integrity_alg, mdev->net_conf->integrity_alg);
 
@@ -3161,14 +3173,18 @@ void drbd_free_bc(struct drbd_backing_dev *ldev)
 void drbd_free_sock(struct drbd_conf *mdev)
 {
         if (mdev->data.socket) {
+                mutex_lock(&mdev->data.mutex);
                 kernel_sock_shutdown(mdev->data.socket, SHUT_RDWR);
                 sock_release(mdev->data.socket);
                 mdev->data.socket = NULL;
+                mutex_unlock(&mdev->data.mutex);
         }
         if (mdev->meta.socket) {
+                mutex_lock(&mdev->meta.mutex);
                 kernel_sock_shutdown(mdev->meta.socket, SHUT_RDWR);
                 sock_release(mdev->meta.socket);
                 mdev->meta.socket = NULL;
+                mutex_unlock(&mdev->meta.mutex);
         }
 }
 
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 4df3b40b105..6429d2b19e0 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -285,8 +285,8 @@ int drbd_set_role(struct drbd_conf *mdev, enum drbd_role new_role, int force)
                 }
 
                 if (r == SS_NO_UP_TO_DATE_DISK && force &&
-                    (mdev->state.disk == D_INCONSISTENT ||
-                     mdev->state.disk == D_OUTDATED)) {
+                    (mdev->state.disk < D_UP_TO_DATE &&
+                     mdev->state.disk >= D_INCONSISTENT)) {
                         mask.disk = D_MASK;
                         val.disk  = D_UP_TO_DATE;
                         forced = 1;
@@ -407,7 +407,7 @@ static int drbd_nl_primary(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp,
         }
 
         reply->ret_code =
-                drbd_set_role(mdev, R_PRIMARY, primary_args.overwrite_peer);
+                drbd_set_role(mdev, R_PRIMARY, primary_args.primary_force);
 
         return 0;
 }
@@ -941,6 +941,25 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
 
         drbd_md_set_sector_offsets(mdev, nbc);
 
+        /* allocate a second IO page if logical_block_size != 512 */
+        logical_block_size = bdev_logical_block_size(nbc->md_bdev);
+        if (logical_block_size == 0)
+                logical_block_size = MD_SECTOR_SIZE;
+
+        if (logical_block_size != MD_SECTOR_SIZE) {
+                if (!mdev->md_io_tmpp) {
+                        struct page *page = alloc_page(GFP_NOIO);
+                        if (!page)
+                                goto force_diskless_dec;
+
+                        dev_warn(DEV, "Meta data's bdev logical_block_size = %d != %d\n",
+                             logical_block_size, MD_SECTOR_SIZE);
+                        dev_warn(DEV, "Workaround engaged (has performance impact).\n");
+
+                        mdev->md_io_tmpp = page;
+                }
+        }
+
         if (!mdev->bitmap) {
                 if (drbd_bm_init(mdev)) {
                         retcode = ERR_NOMEM;
@@ -980,25 +999,6 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
                 goto force_diskless_dec;
         }
 
-        /* allocate a second IO page if logical_block_size != 512 */
-        logical_block_size = bdev_logical_block_size(nbc->md_bdev);
-        if (logical_block_size == 0)
-                logical_block_size = MD_SECTOR_SIZE;
-
-        if (logical_block_size != MD_SECTOR_SIZE) {
-                if (!mdev->md_io_tmpp) {
-                        struct page *page = alloc_page(GFP_NOIO);
-                        if (!page)
-                                goto force_diskless_dec;
-
-                        dev_warn(DEV, "Meta data's bdev logical_block_size = %d != %d\n",
-                             logical_block_size, MD_SECTOR_SIZE);
-                        dev_warn(DEV, "Workaround engaged (has performance impact).\n");
-
-                        mdev->md_io_tmpp = page;
-                }
-        }
-
         /* Reset the "barriers don't work" bits here, then force meta data to
          * be written, to ensure we determine if barriers are supported. */
         if (nbc->dc.no_md_flush)
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index d065c646b35..ed9f1de24a7 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2513,6 +2513,10 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_conf *mdev, enum drbd_rol
         }
 
         if (hg == -100) {
+                /* FIXME this log message is not correct if we end up here
+                 * after an attempted attach on a diskless node.
+                 * We just refuse to attach -- well, we drop the "connection"
+                 * to that disk, in a way... */
                 dev_alert(DEV, "Split-Brain detected, dropping connection!\n");
                 drbd_khelper(mdev, "split-brain");
                 return C_MASK;
@@ -2538,6 +2542,16 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_conf *mdev, enum drbd_rol
                 }
         }
 
+        if (mdev->net_conf->dry_run || test_bit(CONN_DRY_RUN, &mdev->flags)) {
+                if (hg == 0)
+                        dev_info(DEV, "dry-run connect: No resync, would become Connected immediately.\n");
+                else
+                        dev_info(DEV, "dry-run connect: Would become %s, doing a %s resync.",
+                                 drbd_conn_str(hg > 0 ? C_SYNC_SOURCE : C_SYNC_TARGET),
+                                 abs(hg) >= 2 ? "full" : "bit-map based");
+                return C_MASK;
+        }
+
         if (abs(hg) >= 2) {
                 dev_info(DEV, "Writing the whole bitmap, full sync required after drbd_sync_handshake.\n");
                 if (drbd_bitmap_io(mdev, &drbd_bmio_set_n_write, "set_n_write from sync_handshake"))
@@ -2585,7 +2599,7 @@ static int receive_protocol(struct drbd_conf *mdev, struct p_header *h)
         struct p_protocol *p = (struct p_protocol *)h;
         int header_size, data_size;
         int p_proto, p_after_sb_0p, p_after_sb_1p, p_after_sb_2p;
-        int p_want_lose, p_two_primaries;
+        int p_want_lose, p_two_primaries, cf;
         char p_integrity_alg[SHARED_SECRET_MAX] = "";
 
         header_size = sizeof(*p) - sizeof(*h);
@@ -2598,8 +2612,14 @@ static int receive_protocol(struct drbd_conf *mdev, struct p_header *h)
         p_after_sb_0p   = be32_to_cpu(p->after_sb_0p);
         p_after_sb_1p   = be32_to_cpu(p->after_sb_1p);
         p_after_sb_2p   = be32_to_cpu(p->after_sb_2p);
-        p_want_lose     = be32_to_cpu(p->want_lose);
         p_two_primaries = be32_to_cpu(p->two_primaries);
+        cf              = be32_to_cpu(p->conn_flags);
+        p_want_lose = cf & CF_WANT_LOSE;
+
+        clear_bit(CONN_DRY_RUN, &mdev->flags);
+
+        if (cf & CF_DRY_RUN)
+                set_bit(CONN_DRY_RUN, &mdev->flags);
 
         if (p_proto != mdev->net_conf->wire_protocol) {
                 dev_err(DEV, "incompatible communication protocols\n");
@@ -3118,13 +3138,16 @@ static int receive_state(struct drbd_conf *mdev, struct p_header *h)
 
                 put_ldev(mdev);
                 if (nconn == C_MASK) {
+                        nconn = C_CONNECTED;
                         if (mdev->state.disk == D_NEGOTIATING) {
                                 drbd_force_state(mdev, NS(disk, D_DISKLESS));
-                                nconn = C_CONNECTED;
                         } else if (peer_state.disk == D_NEGOTIATING) {
                                 dev_err(DEV, "Disk attach process on the peer node was aborted.\n");
                                 peer_state.disk = D_DISKLESS;
+                                real_peer_disk = D_DISKLESS;
                         } else {
+                                if (test_and_clear_bit(CONN_DRY_RUN, &mdev->flags))
+                                        return FALSE;
                                 D_ASSERT(oconn == C_WF_REPORT_PARAMS);
                                 drbd_force_state(mdev, NS(conn, C_DISCONNECTING));
                                 return FALSE;
@@ -3594,10 +3617,7 @@ static void drbd_disconnect(struct drbd_conf *mdev)
 
         /* asender does not clean up anything. it must not interfere, either */
         drbd_thread_stop(&mdev->asender);
-
-        mutex_lock(&mdev->data.mutex);
         drbd_free_sock(mdev);
-        mutex_unlock(&mdev->data.mutex);
 
         spin_lock_irq(&mdev->req_lock);
         _drbd_wait_ee_list_empty(mdev, &mdev->active_ee);
@@ -4054,6 +4074,8 @@ static int got_PingAck(struct drbd_conf *mdev, struct p_header *h)
 {
         /* restore idle timeout */
         mdev->meta.socket->sk->sk_rcvtimeo = mdev->net_conf->ping_int*HZ;
+        if (!test_and_set_bit(GOT_PING_ACK, &mdev->flags))
+                wake_up(&mdev->misc_wait);
 
         return TRUE;
 }
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index b453c2bca3b..44bf6d11197 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -938,7 +938,8 @@ int w_e_end_csum_rs_req(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
 
                 if (eq) {
                         drbd_set_in_sync(mdev, e->sector, e->size);
-                        mdev->rs_same_csum++;
+                        /* rs_same_csums unit is BM_BLOCK_SIZE */
+                        mdev->rs_same_csum += e->size >> BM_BLOCK_SHIFT;
                         ok = drbd_send_ack(mdev, P_RS_IS_IN_SYNC, e);
                 } else {
                         inc_rs_pending(mdev);
@@ -1288,6 +1289,14 @@ int drbd_alter_sa(struct drbd_conf *mdev, int na)
         return retcode;
 }
 
+static void ping_peer(struct drbd_conf *mdev)
+{
+        clear_bit(GOT_PING_ACK, &mdev->flags);
+        request_ping(mdev);
+        wait_event(mdev->misc_wait,
+                   test_bit(GOT_PING_ACK, &mdev->flags) || mdev->state.conn < C_CONNECTED);
+}
+
 /**
  * drbd_start_resync() - Start the resync process
  * @mdev:       DRBD device.
@@ -1371,7 +1380,6 @@ void drbd_start_resync(struct drbd_conf *mdev, enum drbd_conns side)
                 _drbd_pause_after(mdev);
         }
         write_unlock_irq(&global_state_lock);
-        drbd_state_unlock(mdev);
         put_ldev(mdev);
 
         if (r == SS_SUCCESS) {
@@ -1382,11 +1390,8 @@ void drbd_start_resync(struct drbd_conf *mdev, enum drbd_conns side)
 
                 if (mdev->rs_total == 0) {
                         /* Peer still reachable? Beware of failing before-resync-target handlers! */
-                        request_ping(mdev);
-                        __set_current_state(TASK_INTERRUPTIBLE);
-                        schedule_timeout(mdev->net_conf->ping_timeo*HZ/9); /* 9 instead 10 */
+                        ping_peer(mdev);
                         drbd_resync_finished(mdev);
-                        return;
                 }
 
                 /* ns.conn may already be != mdev->state.conn,
@@ -1398,6 +1403,7 @@ void drbd_start_resync(struct drbd_conf *mdev, enum drbd_conns side)
 
                 drbd_md_sync(mdev);
         }
+        drbd_state_unlock(mdev);
 }
 
 int drbd_worker(struct drbd_thread *thi)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cb69929d917..8546d123b9a 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -237,6 +237,8 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
                 if (ret)
                         goto fail;
 
+                file_update_time(file);
+
                 transfer_result = lo_do_transfer(lo, WRITE, page, offset,
                                 bvec->bv_page, bv_offs, size, IV);
                 copied = size;
diff --git a/drivers/block/paride/pcd.c b/drivers/block/paride/pcd.c
index 8866ca369d5..71acf4e5335 100644
--- a/drivers/block/paride/pcd.c
+++ b/drivers/block/paride/pcd.c
@@ -341,11 +341,11 @@ static int pcd_wait(struct pcd_unit *cd, int go, int stop, char *fun, char *msg)
                && (j++ < PCD_SPIN))
                 udelay(PCD_DELAY);
 
-        if ((r & (IDE_ERR & stop)) || (j >= PCD_SPIN)) {
+        if ((r & (IDE_ERR & stop)) || (j > PCD_SPIN)) {
                 s = read_reg(cd, 7);
                 e = read_reg(cd, 1);
                 p = read_reg(cd, 2);
-                if (j >= PCD_SPIN)
+                if (j > PCD_SPIN)
                         e |= 0x100;
                 if (fun)
                         printk("%s: %s %s: alt=0x%x stat=0x%x err=0x%x"
diff --git a/drivers/block/paride/pf.c b/drivers/block/paride/pf.c
index ddb4f9abd48..c059aab3006 100644
--- a/drivers/block/paride/pf.c
+++ b/drivers/block/paride/pf.c
@@ -391,11 +391,11 @@ static int pf_wait(struct pf_unit *pf, int go, int stop, char *fun, char *msg)
                && (j++ < PF_SPIN))
                 udelay(PF_SPIN_DEL);
 
-        if ((r & (STAT_ERR & stop)) || (j >= PF_SPIN)) {
+        if ((r & (STAT_ERR & stop)) || (j > PF_SPIN)) {
                 s = read_reg(pf, 7);
                 e = read_reg(pf, 1);
                 p = read_reg(pf, 2);
-                if (j >= PF_SPIN)
+                if (j > PF_SPIN)
                         e |= 0x100;
                 if (fun)
                         printk("%s: %s %s: alt=0x%x stat=0x%x err=0x%x"
diff --git a/drivers/block/paride/pt.c b/drivers/block/paride/pt.c
index 1e4006e18f0..bc5825fdeaa 100644
--- a/drivers/block/paride/pt.c
+++ b/drivers/block/paride/pt.c
@@ -274,11 +274,11 @@ static int pt_wait(struct pt_unit *tape, int go, int stop, char *fun, char *msg)
                && (j++ < PT_SPIN))
                 udelay(PT_SPIN_DEL);
 
-        if ((r & (STAT_ERR & stop)) || (j >= PT_SPIN)) {
+        if ((r & (STAT_ERR & stop)) || (j > PT_SPIN)) {
                 s = read_reg(pi, 7);
                 e = read_reg(pi, 1);
                 p = read_reg(pi, 2);
-                if (j >= PT_SPIN)
+                if (j > PT_SPIN)
                         e |= 0x100;
                 if (fun)
                         printk("%s: %s %s: alt=0x%x stat=0x%x err=0x%x"
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 4b12b820c9a..2138a7ae050 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -348,14 +348,13 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
         set_capacity(vblk->disk, cap);
 
         /* We can handle whatever the host told us to handle. */
-        blk_queue_max_phys_segments(q, vblk->sg_elems-2);
-        blk_queue_max_hw_segments(q, vblk->sg_elems-2);
+        blk_queue_max_segments(q, vblk->sg_elems-2);
 
         /* No need to bounce any requests */
         blk_queue_bounce_limit(q, BLK_BOUNCE_ANY);
 
         /* No real sector limit. */
-        blk_queue_max_sectors(q, -1U);
+        blk_queue_max_hw_sectors(q, -1U);
 
         /* Host can optionally specify maximum segment size and number of
          * segments. */
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 58c62ff42ab..8b827f37b03 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2186,7 +2186,7 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
         blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
 
         gd->driverfs_dev = &sdp->sdev_gendev;
-        gd->flags = GENHD_FL_EXT_DEVT | GENHD_FL_DRIVERFS;
+        gd->flags = GENHD_FL_EXT_DEVT;
         if (sdp->removable)
                 gd->flags |= GENHD_FL_REMOVABLE;
 
diff --git a/fs/bio.c b/fs/bio.c
index e1f922184b4..e7bf6ca64dc 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -554,7 +554,7 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
                                         .bi_rw = bio->bi_rw,
                                 };
 
-                                if (q->merge_bvec_fn(q, &bvm, prev) < len) {
+                                if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) {
                                         prev->bv_len -= len;
                                         return 0;
                                 }
@@ -607,7 +607,7 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
                  * merge_bvec_fn() returns number of bytes it can accept
                  * at this offset
                  */
-                if (q->merge_bvec_fn(q, &bvm, bvec) < len) {
+                if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) {
                         bvec->bv_page = NULL;
                         bvec->bv_len = 0;
                         bvec->bv_offset = 0;
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 781a322ccb4..4b37f7cea4d 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -554,108 +554,85 @@ select_queue:
         return ret;
 }
 
-static void unpin_sb_for_writeback(struct super_block **psb)
+static void unpin_sb_for_writeback(struct super_block *sb)
 {
-        struct super_block *sb = *psb;
-
-        if (sb) {
-                up_read(&sb->s_umount);
-                put_super(sb);
-                *psb = NULL;
-        }
+        up_read(&sb->s_umount);
+        put_super(sb);
 }
 
+enum sb_pin_state {
+        SB_PINNED,
+        SB_NOT_PINNED,
+        SB_PIN_FAILED
+};
+
 /*
  * For WB_SYNC_NONE writeback, the caller does not have the sb pinned
  * before calling writeback. So make sure that we do pin it, so it doesn't
  * go away while we are writing inodes from it.
- *
- * Returns 0 if the super was successfully pinned (or pinning wasn't needed),
- * 1 if we failed.
  */
-static int pin_sb_for_writeback(struct writeback_control *wbc,
-                                struct inode *inode, struct super_block **psb)
+static enum sb_pin_state pin_sb_for_writeback(struct writeback_control *wbc,
+                                              struct super_block *sb)
 {
-        struct super_block *sb = inode->i_sb;
-
-        /*
-         * If this sb is already pinned, nothing more to do. If not and
-         * *psb is non-NULL, unpin the old one first
-         */
-        if (sb == *psb)
-                return 0;
-        else if (*psb)
-                unpin_sb_for_writeback(psb);
-
         /*
          * Caller must already hold the ref for this
          */
         if (wbc->sync_mode == WB_SYNC_ALL) {
                 WARN_ON(!rwsem_is_locked(&sb->s_umount));
-                return 0;
+                return SB_NOT_PINNED;
         }
-
         spin_lock(&sb_lock);
         sb->s_count++;
         if (down_read_trylock(&sb->s_umount)) {
                 if (sb->s_root) {
                         spin_unlock(&sb_lock);
-                        goto pinned;
+                        return SB_PINNED;
                 }
                 /*
                  * umounted, drop rwsem again and fall through to failure
                  */
                 up_read(&sb->s_umount);
         }
-
         sb->s_count--;
         spin_unlock(&sb_lock);
-        return 1;
-pinned:
-        *psb = sb;
-        return 0;
+        return SB_PIN_FAILED;
 }
 
-static void writeback_inodes_wb(struct bdi_writeback *wb,
-                                struct writeback_control *wbc)
+/*
+ * Write a portion of b_io inodes which belong to @sb.
+ * If @wbc->sb != NULL, then find and write all such
+ * inodes. Otherwise write only ones which go sequentially
+ * in reverse order.
+ * Return 1, if the caller writeback routine should be
+ * interrupted. Otherwise return 0.
+ */
+static int writeback_sb_inodes(struct super_block *sb,
+                               struct bdi_writeback *wb,
+                               struct writeback_control *wbc)
 {
-        struct super_block *sb = wbc->sb, *pin_sb = NULL;
-        const unsigned long start = jiffies;    /* livelock avoidance */
-
-        spin_lock(&inode_lock);
-
-        if (!wbc->for_kupdate || list_empty(&wb->b_io))
-                queue_io(wb, wbc->older_than_this);
-
         while (!list_empty(&wb->b_io)) {
-                struct inode *inode = list_entry(wb->b_io.prev,
-                                                struct inode, i_list);
                 long pages_skipped;
-
-                /*
-                 * super block given and doesn't match, skip this inode
-                 */
-                if (sb && sb != inode->i_sb) {
+                struct inode *inode = list_entry(wb->b_io.prev,
+                                                 struct inode, i_list);
+                if (wbc->sb && sb != inode->i_sb) {
+                        /* super block given and doesn't
+                           match, skip this inode */
                         redirty_tail(inode);
                         continue;
                 }
-
+                if (sb != inode->i_sb)
+                        /* finish with this superblock */
+                        return 0;
                 if (inode->i_state & (I_NEW | I_WILL_FREE)) {
                         requeue_io(inode);
                         continue;
                 }
-
                 /*
                  * Was this inode dirtied after sync_sb_inodes was called?
                  * This keeps sync from extra jobs and livelock.
                  */
-                if (inode_dirtied_after(inode, start))
-                        break;
-
-                if (pin_sb_for_writeback(wbc, inode, &pin_sb)) {
-                        requeue_io(inode);
-                        continue;
-                }
+                if (inode_dirtied_after(inode, wbc->wb_start))
+                        return 1;
 
                 BUG_ON(inode->i_state & (I_FREEING | I_CLEAR));
                 __iget(inode);
@@ -674,14 +651,50 @@ static void writeback_inodes_wb(struct bdi_writeback *wb,
                 spin_lock(&inode_lock);
                 if (wbc->nr_to_write <= 0) {
                         wbc->more_io = 1;
-                        break;
+                        return 1;
                 }
                 if (!list_empty(&wb->b_more_io))
                         wbc->more_io = 1;
         }
+        /* b_io is empty */
+        return 1;
+}
+
+static void writeback_inodes_wb(struct bdi_writeback *wb,
+                                struct writeback_control *wbc)
+{
+        int ret = 0;
 
-        unpin_sb_for_writeback(&pin_sb);
+        wbc->wb_start = jiffies; /* livelock avoidance */
+        spin_lock(&inode_lock);
+        if (!wbc->for_kupdate || list_empty(&wb->b_io))
+                queue_io(wb, wbc->older_than_this);
+
+        while (!list_empty(&wb->b_io)) {
+                struct inode *inode = list_entry(wb->b_io.prev,
+                                                 struct inode, i_list);
+                struct super_block *sb = inode->i_sb;
+                enum sb_pin_state state;
+
+                if (wbc->sb && sb != wbc->sb) {
+                        /* super block given and doesn't
+                           match, skip this inode */
+                        redirty_tail(inode);
+                        continue;
+                }
+                state = pin_sb_for_writeback(wbc, sb);
+
+                if (state == SB_PIN_FAILED) {
+                        requeue_io(inode);
+                        continue;
+                }
+                ret = writeback_sb_inodes(sb, wb, wbc);
 
+                if (state == SB_PINNED)
+                        unpin_sb_for_writeback(sb);
+                if (ret)
+                        break;
+        }
         spin_unlock(&inode_lock);
         /* Leave any unwritten inodes on b_io */
 }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ebd22dbed86..6690e8bae7b 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -158,7 +158,6 @@ enum rq_flag_bits {
 struct request {
         struct list_head queuelist;
         struct call_single_data csd;
-        int cpu;
 
         struct request_queue *q;
 
@@ -166,9 +165,11 @@ struct request {
         enum rq_cmd_type_bits cmd_type;
         unsigned long atomic_flags;
 
+        int cpu;
+
         /* the following two fields are internal, NEVER access directly */
-        sector_t __sector;              /* sector cursor */
         unsigned int __data_len;        /* total data len */
+        sector_t __sector;              /* sector cursor */
 
         struct bio *bio;
         struct bio *biotail;
@@ -201,20 +202,20 @@ struct request {
 
         unsigned short ioprio;
 
+        int ref_count;
+
         void *special;          /* opaque pointer available for LLD use */
         char *buffer;           /* kaddr of the current segment if available */
 
         int tag;
         int errors;
 
-        int ref_count;
-
         /*
          * when request is used as a packet command carrier
          */
-        unsigned short cmd_len;
         unsigned char __cmd[BLK_MAX_CDB];
         unsigned char *cmd;
+        unsigned short cmd_len;
 
         unsigned int extra_len; /* length of alignment and padding */
         unsigned int sense_len;
@@ -921,26 +922,7 @@ extern void blk_cleanup_queue(struct request_queue *);
 extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
 extern void blk_queue_bounce_limit(struct request_queue *, u64);
 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
-
-/* Temporary compatibility wrapper */
-static inline void blk_queue_max_sectors(struct request_queue *q, unsigned int max)
-{
-        blk_queue_max_hw_sectors(q, max);
-}
-
 extern void blk_queue_max_segments(struct request_queue *, unsigned short);
-
-static inline void blk_queue_max_phys_segments(struct request_queue *q, unsigned short max)
-{
-        blk_queue_max_segments(q, max);
-}
-
-static inline void blk_queue_max_hw_segments(struct request_queue *q, unsigned short max)
-{
-        blk_queue_max_segments(q, max);
-}
-
-
 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
 extern void blk_queue_max_discard_sectors(struct request_queue *q,
                 unsigned int max_discard_sectors);
@@ -1030,11 +1012,6 @@ static inline int sb_issue_discard(struct super_block *sb,
 
 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 
-#define MAX_PHYS_SEGMENTS 128
-#define MAX_HW_SEGMENTS 128
-#define SAFE_MAX_SECTORS 255
-#define MAX_SEGMENT_SIZE        65536
-
 enum blk_default_limits {
         BLK_MAX_SEGMENTS        = 128,
         BLK_SAFE_MAX_SECTORS    = 255,
diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index 78962272338..4341b1a97a3 100644
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -56,7 +56,7 @@ extern const char *drbd_buildtag(void);
 #define REL_VERSION "8.3.7"
 #define API_VERSION 88
 #define PRO_VERSION_MIN 86
-#define PRO_VERSION_MAX 91
+#define PRO_VERSION_MAX 92
 
 
 enum drbd_io_error_p {
diff --git a/include/linux/drbd_nl.h b/include/linux/drbd_nl.h
index a4d82f89599..f7431a4ca60 100644
--- a/include/linux/drbd_nl.h
+++ b/include/linux/drbd_nl.h
@@ -12,7 +12,7 @@
 #endif
 
 NL_PACKET(primary, 1,
-       NL_BIT(          1,      T_MAY_IGNORE,   overwrite_peer)
+       NL_BIT(          1,      T_MAY_IGNORE,   primary_force)
 )
 
 NL_PACKET(secondary, 2, )
@@ -63,6 +63,7 @@ NL_PACKET(net_conf, 5,
         NL_BIT(         41,     T_MAY_IGNORE,   always_asbp)
         NL_BIT(         61,     T_MAY_IGNORE,   no_cork)
         NL_BIT(         62,     T_MANDATORY,    auto_sndbuf_size)
+        NL_BIT(         70,     T_MANDATORY,    dry_run)
 )
 
 NL_PACKET(disconnect, 6, )
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 56b50514ab2..5f2f4c4d8fb 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -109,7 +109,7 @@ struct hd_struct {
 };
 
 #define GENHD_FL_REMOVABLE                      1
-#define GENHD_FL_DRIVERFS                       2
+/* 2 is unused */
 #define GENHD_FL_MEDIA_CHANGE_NOTIFY            4
 #define GENHD_FL_CD                             8
 #define GENHD_FL_UP                             16
diff --git a/include/linux/i2o.h b/include/linux/i2o.h
index 87018dc5527..9e7a12d6385 100644
--- a/include/linux/i2o.h
+++ b/include/linux/i2o.h
@@ -782,7 +782,6 @@ extern int i2o_exec_lct_get(struct i2o_controller *);
 #define to_i2o_driver(drv) container_of(drv,struct i2o_driver, driver)
 #define to_i2o_device(dev) container_of(dev, struct i2o_device, device)
 #define to_i2o_controller(dev) container_of(dev, struct i2o_controller, device)
-#define kobj_to_i2o_device(kobj) to_i2o_device(container_of(kobj, struct device, kobj))
 
 /**
  *      i2o_out_to_virt - Turn an I2O message to a virtual address
diff --git a/include/linux/lcm.h b/include/linux/lcm.h
new file mode 100644
index 00000000000..7bf01d779b4
--- /dev/null
+++ b/include/linux/lcm.h
@@ -0,0 +1,8 @@
+#ifndef _LCM_H
+#define _LCM_H
+
+#include <linux/compiler.h>
+
+unsigned long lcm(unsigned long a, unsigned long b) __attribute_const__;
+
+#endif /* _LCM_H */
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 76e8903cd20..36520ded3e0 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -34,6 +34,9 @@ struct writeback_control {
         enum writeback_sync_modes sync_mode;
         unsigned long *older_than_this; /* If !NULL, only write back inodes
                                            older than this */
+        unsigned long wb_start;         /* Time writeback_inodes_wb was
+                                           called. This is needed to avoid
+                                           extra jobs and livelock */
         long nr_to_write;               /* Write this many pages, and decrement
                                            this for each page written */
         long pages_skipped;             /* Pages which were not written */
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 5fb72733331..d870a918559 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -40,6 +40,16 @@ DECLARE_EVENT_CLASS(block_rq_with_error,
                   __entry->nr_sector, __entry->errors)
 );
 
+/**
+ * block_rq_abort - abort block operation request
+ * @q: queue containing the block operation request
+ * @rq: block IO operation request
+ *
+ * Called immediately after pending block IO operation request @rq in
+ * queue @q is aborted. The fields in the operation request @rq
+ * can be examined to determine which device and sectors the pending
+ * operation would access.
+ */
 DEFINE_EVENT(block_rq_with_error, block_rq_abort,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
@@ -47,6 +57,15 @@ DEFINE_EVENT(block_rq_with_error, block_rq_abort,
         TP_ARGS(q, rq)
 );
 
+/**
+ * block_rq_requeue - place block IO request back on a queue
+ * @q: queue holding operation
+ * @rq: block IO operation request
+ *
+ * The block operation request @rq is being placed back into queue
+ * @q.  For some reason the request was not completed and needs to be
+ * put back in the queue.
+ */
 DEFINE_EVENT(block_rq_with_error, block_rq_requeue,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
@@ -54,6 +73,17 @@ DEFINE_EVENT(block_rq_with_error, block_rq_requeue,
         TP_ARGS(q, rq)
 );
 
+/**
+ * block_rq_complete - block IO operation completed by device driver
+ * @q: queue containing the block operation request
+ * @rq: block operations request
+ *
+ * The block_rq_complete tracepoint event indicates that some portion
+ * of operation request has been completed by the device driver.  If
+ * the @rq->bio is %NULL, then there is absolutely no additional work to
+ * do for the request. If @rq->bio is non-NULL then there is
+ * additional work required to complete the request.
+ */
 DEFINE_EVENT(block_rq_with_error, block_rq_complete,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
@@ -95,6 +125,16 @@ DECLARE_EVENT_CLASS(block_rq,
                   __entry->nr_sector, __entry->comm)
 );
 
+/**
+ * block_rq_insert - insert block operation request into queue
+ * @q: target queue
+ * @rq: block IO operation request
+ *
+ * Called immediately before block operation request @rq is inserted
+ * into queue @q.  The fields in the operation request @rq struct can
+ * be examined to determine which device and sectors the pending
+ * operation would access.
+ */
 DEFINE_EVENT(block_rq, block_rq_insert,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
@@ -102,6 +142,14 @@ DEFINE_EVENT(block_rq, block_rq_insert,
         TP_ARGS(q, rq)
 );
 
+/**
+ * block_rq_issue - issue pending block IO request operation to device driver
+ * @q: queue holding operation
+ * @rq: block IO operation operation request
+ *
+ * Called when block operation request @rq from queue @q is sent to a
+ * device driver for processing.
+ */
 DEFINE_EVENT(block_rq, block_rq_issue,
 
         TP_PROTO(struct request_queue *q, struct request *rq),
@@ -109,6 +157,17 @@ DEFINE_EVENT(block_rq, block_rq_issue,
         TP_ARGS(q, rq)
 );
 
+/**
+ * block_bio_bounce - used bounce buffer when processing block operation
+ * @q: queue holding the block operation
+ * @bio: block operation
+ *
+ * A bounce buffer was used to handle the block operation @bio in @q.
+ * This occurs when hardware limitations prevent a direct transfer of
+ * data between the @bio data memory area and the IO device.  Use of a
+ * bounce buffer requires extra copying of data and decreases
+ * performance.
+ */
 TRACE_EVENT(block_bio_bounce,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
@@ -138,6 +197,14 @@ TRACE_EVENT(block_bio_bounce,
                   __entry->nr_sector, __entry->comm)
 );
 
+/**
+ * block_bio_complete - completed all work on the block operation
+ * @q: queue holding the block operation
+ * @bio: block operation completed
+ *
+ * This tracepoint indicates there is no further work to do on this
+ * block IO operation @bio.
+ */
 TRACE_EVENT(block_bio_complete,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
@@ -193,6 +260,14 @@ DECLARE_EVENT_CLASS(block_bio,
                   __entry->nr_sector, __entry->comm)
 );
 
+/**
+ * block_bio_backmerge - merging block operation to the end of an existing operation
+ * @q: queue holding operation
+ * @bio: new block operation to merge
+ *
+ * Merging block request @bio to the end of an existing block request
+ * in queue @q.
+ */
 DEFINE_EVENT(block_bio, block_bio_backmerge,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
@@ -200,6 +275,14 @@ DEFINE_EVENT(block_bio, block_bio_backmerge,
         TP_ARGS(q, bio)
 );
 
+/**
+ * block_bio_frontmerge - merging block operation to the beginning of an existing operation
+ * @q: queue holding operation
+ * @bio: new block operation to merge
+ *
+ * Merging block IO operation @bio to the beginning of an existing block
+ * operation in queue @q.
+ */
 DEFINE_EVENT(block_bio, block_bio_frontmerge,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
@@ -207,6 +290,13 @@ DEFINE_EVENT(block_bio, block_bio_frontmerge,
         TP_ARGS(q, bio)
 );
 
+/**
+ * block_bio_queue - putting new block IO operation in queue
+ * @q: queue holding operation
+ * @bio: new block operation
+ *
+ * About to place the block IO operation @bio into queue @q.
+ */
 DEFINE_EVENT(block_bio, block_bio_queue,
 
         TP_PROTO(struct request_queue *q, struct bio *bio),
@@ -243,6 +333,15 @@ DECLARE_EVENT_CLASS(block_get_rq,
                   __entry->nr_sector, __entry->comm)
 );
 
+/**
+ * block_getrq - get a free request entry in queue for block IO operations
+ * @q: queue for operations
+ * @bio: pending block IO operation
+ * @rw: low bit indicates a read (%0) or a write (%1)
+ *
+ * A request struct for queue @q has been allocated to handle the
+ * block IO operation @bio.
+ */
 DEFINE_EVENT(block_get_rq, block_getrq,
 
         TP_PROTO(struct request_queue *q, struct bio *bio, int rw),
@@ -250,6 +349,17 @@ DEFINE_EVENT(block_get_rq, block_getrq,
         TP_ARGS(q, bio, rw)
 );
 
+/**
+ * block_sleeprq - waiting to get a free request entry in queue for block IO operation
+ * @q: queue for operation
+ * @bio: pending block IO operation
+ * @rw: low bit indicates a read (%0) or a write (%1)
+ *
+ * In the case where a request struct cannot be provided for queue @q
+ * the process needs to wait for an request struct to become
+ * available.  This tracepoint event is generated each time the
+ * process goes to sleep waiting for request struct become available.
+ */
 DEFINE_EVENT(block_get_rq, block_sleeprq,
 
         TP_PROTO(struct request_queue *q, struct bio *bio, int rw),
@@ -257,6 +367,14 @@ DEFINE_EVENT(block_get_rq, block_sleeprq,
         TP_ARGS(q, bio, rw)
 );
 
+/**
+ * block_plug - keep operations requests in request queue
+ * @q: request queue to plug
+ *
+ * Plug the request queue @q.  Do not allow block operation requests
+ * to be sent to the device driver. Instead, accumulate requests in
+ * the queue to improve throughput performance of the block device.
+ */
 TRACE_EVENT(block_plug,
 
         TP_PROTO(struct request_queue *q),
@@ -293,6 +411,13 @@ DECLARE_EVENT_CLASS(block_unplug,
         TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
 );
 
+/**
+ * block_unplug_timer - timed release of operations requests in queue to device driver
+ * @q: request queue to unplug
+ *
+ * Unplug the request queue @q because a timer expired and allow block
+ * operation requests to be sent to the device driver.
+ */
 DEFINE_EVENT(block_unplug, block_unplug_timer,
 
         TP_PROTO(struct request_queue *q),
@@ -300,6 +425,13 @@ DEFINE_EVENT(block_unplug, block_unplug_timer,
         TP_ARGS(q)
 );
 
+/**
+ * block_unplug_io - release of operations requests in request queue
+ * @q: request queue to unplug
+ *
+ * Unplug request queue @q because device driver is scheduled to work
+ * on elements in the request queue.
+ */
 DEFINE_EVENT(block_unplug, block_unplug_io,
 
         TP_PROTO(struct request_queue *q),
@@ -307,6 +439,17 @@ DEFINE_EVENT(block_unplug, block_unplug_io,
         TP_ARGS(q)
 );
 
+/**
+ * block_split - split a single bio struct into two bio structs
+ * @q: queue containing the bio
+ * @bio: block operation being split
+ * @new_sector: The starting sector for the new bio
+ *
+ * The bio request @bio in request queue @q needs to be split into two
+ * bio requests. The newly created @bio request starts at
+ * @new_sector. This split may be required due to hardware limitation
+ * such as operation crossing device boundaries in a RAID system.
+ */
 TRACE_EVENT(block_split,
 
         TP_PROTO(struct request_queue *q, struct bio *bio,
@@ -337,6 +480,16 @@ TRACE_EVENT(block_split,
                   __entry->comm)
 );
 
+/**
+ * block_remap - map request for a partition to the raw device
+ * @q: queue holding the operation
+ * @bio: revised operation
+ * @dev: device for the operation
+ * @from: original sector for the operation
+ *
+ * An operation for a partition on a block device has been mapped to the
+ * raw block device.
+ */
 TRACE_EVENT(block_remap,
 
         TP_PROTO(struct request_queue *q, struct bio *bio, dev_t dev,
@@ -370,6 +523,17 @@ TRACE_EVENT(block_remap,
                   (unsigned long long)__entry->old_sector)
 );
 
+/**
+ * block_rq_remap - map request for a block operation request
+ * @q: queue holding the operation
+ * @rq: block IO operation request
+ * @dev: device for the operation
+ * @from: original sector for the operation
+ *
+ * The block operation request @rq in @q has been remapped.  The block
+ * operation request @rq holds the current information and @from hold
+ * the original sector.
+ */
 TRACE_EVENT(block_rq_remap,
 
         TP_PROTO(struct request_queue *q, struct request *rq, dev_t dev,
diff --git a/lib/Makefile b/lib/Makefile
index 2e152aed719..0d4015205c6 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -21,7 +21,7 @@ lib-y	+= kobject.o kref.o klist.o
 
 obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
          bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
-         string_helpers.o gcd.o list_sort.o
+         string_helpers.o gcd.o lcm.o list_sort.o
 
 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
 CFLAGS_kobject.o += -DDEBUG
diff --git a/lib/lcm.c b/lib/lcm.c
new file mode 100644
index 00000000000..157cd88a6ff
--- /dev/null
+++ b/lib/lcm.c
@@ -0,0 +1,15 @@
+#include <linux/kernel.h>
+#include <linux/gcd.h>
+#include <linux/module.h>
+
+/* Lowest common multiple */
+unsigned long lcm(unsigned long a, unsigned long b)
+{
+        if (a && b)
+                return (a * b) / gcd(a, b);
+        else if (b)
+                return b;
+
+        return a;
+}
+EXPORT_SYMBOL_GPL(lcm);
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 0e8ca034770..f13e067e146 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -227,6 +227,9 @@ static struct device_attribute bdi_dev_attrs[] = {
 static __init int bdi_class_init(void)
 {
         bdi_class = class_create(THIS_MODULE, "bdi");
+        if (IS_ERR(bdi_class))
+                return PTR_ERR(bdi_class);
+
         bdi_class->dev_attrs = bdi_dev_attrs;
         bdi_debug_init();
         return 0;