18 files changed, 580 insertions, 317 deletions

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 019e8af449ab..6ea5cd0a595f 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -48,6 +48,9 @@ struct btrfs_worker_thread {
         /* number of things on the pending list */
         atomic_t num_pending;
 
+        /* reference counter for this struct */
+        atomic_t refs;
+
         unsigned long sequence;
 
         /* protects the pending list. */
@@ -93,17 +96,40 @@ static void check_busy_worker(struct btrfs_worker_thread *worker)
         }
 }
 
-static noinline int run_ordered_completions(struct btrfs_workers *workers,
-                                            struct btrfs_work *work)
+static void check_pending_worker_creates(struct btrfs_worker_thread *worker)
 {
+        struct btrfs_workers *workers = worker->workers;
         unsigned long flags;
 
+        rmb();
+        if (!workers->atomic_start_pending)
+                return;
+
+        spin_lock_irqsave(&workers->lock, flags);
+        if (!workers->atomic_start_pending)
+                goto out;
+
+        workers->atomic_start_pending = 0;
+        if (workers->num_workers >= workers->max_workers)
+                goto out;
+
+        spin_unlock_irqrestore(&workers->lock, flags);
+        btrfs_start_workers(workers, 1);
+        return;
+
+out:
+        spin_unlock_irqrestore(&workers->lock, flags);
+}
+
+static noinline int run_ordered_completions(struct btrfs_workers *workers,
+                                            struct btrfs_work *work)
+{
         if (!workers->ordered)
                 return 0;
 
         set_bit(WORK_DONE_BIT, &work->flags);
 
-        spin_lock_irqsave(&workers->lock, flags);
+        spin_lock(&workers->order_lock);
 
         while (1) {
                 if (!list_empty(&workers->prio_order_list)) {
@@ -126,45 +152,117 @@ static noinline int run_ordered_completions(struct btrfs_workers *workers,
                 if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
                         break;
 
-                spin_unlock_irqrestore(&workers->lock, flags);
+                spin_unlock(&workers->order_lock);
 
                 work->ordered_func(work);
 
                 /* now take the lock again and call the freeing code */
-                spin_lock_irqsave(&workers->lock, flags);
+                spin_lock(&workers->order_lock);
                 list_del(&work->order_list);
                 work->ordered_free(work);
         }
 
-        spin_unlock_irqrestore(&workers->lock, flags);
+        spin_unlock(&workers->order_lock);
         return 0;
 }
 
+static void put_worker(struct btrfs_worker_thread *worker)
+{
+        if (atomic_dec_and_test(&worker->refs))
+                kfree(worker);
+}
+
+static int try_worker_shutdown(struct btrfs_worker_thread *worker)
+{
+        int freeit = 0;
+
+        spin_lock_irq(&worker->lock);
+        spin_lock_irq(&worker->workers->lock);
+        if (worker->workers->num_workers > 1 &&
+            worker->idle &&
+            !worker->working &&
+            !list_empty(&worker->worker_list) &&
+            list_empty(&worker->prio_pending) &&
+            list_empty(&worker->pending)) {
+                freeit = 1;
+                list_del_init(&worker->worker_list);
+                worker->workers->num_workers--;
+        }
+        spin_unlock_irq(&worker->workers->lock);
+        spin_unlock_irq(&worker->lock);
+
+        if (freeit)
+                put_worker(worker);
+        return freeit;
+}
+
+static struct btrfs_work *get_next_work(struct btrfs_worker_thread *worker,
+                                        struct list_head *prio_head,
+                                        struct list_head *head)
+{
+        struct btrfs_work *work = NULL;
+        struct list_head *cur = NULL;
+
+        if(!list_empty(prio_head))
+                cur = prio_head->next;
+
+        smp_mb();
+        if (!list_empty(&worker->prio_pending))
+                goto refill;
+
+        if (!list_empty(head))
+                cur = head->next;
+
+        if (cur)
+                goto out;
+
+refill:
+        spin_lock_irq(&worker->lock);
+        list_splice_tail_init(&worker->prio_pending, prio_head);
+        list_splice_tail_init(&worker->pending, head);
+
+        if (!list_empty(prio_head))
+                cur = prio_head->next;
+        else if (!list_empty(head))
+                cur = head->next;
+        spin_unlock_irq(&worker->lock);
+
+        if (!cur)
+                goto out_fail;
+
+out:
+        work = list_entry(cur, struct btrfs_work, list);
+
+out_fail:
+        return work;
+}
+
 /*
  * main loop for servicing work items
  */
 static int worker_loop(void *arg)
 {
         struct btrfs_worker_thread *worker = arg;
-        struct list_head *cur;
+        struct list_head head;
+        struct list_head prio_head;
         struct btrfs_work *work;
+
+        INIT_LIST_HEAD(&head);
+        INIT_LIST_HEAD(&prio_head);
+
         do {
-                spin_lock_irq(&worker->lock);
-again_locked:
+again:
                 while (1) {
-                        if (!list_empty(&worker->prio_pending))
-                                cur = worker->prio_pending.next;
-                        else if (!list_empty(&worker->pending))
-                                cur = worker->pending.next;
-                        else
+
+
+                        work = get_next_work(worker, &prio_head, &head);
+                        if (!work)
                                 break;
 
-                        work = list_entry(cur, struct btrfs_work, list);
                         list_del(&work->list);
                         clear_bit(WORK_QUEUED_BIT, &work->flags);
 
                         work->worker = worker;
-                        spin_unlock_irq(&worker->lock);
 
                         work->func(work);
 
@@ -175,9 +273,13 @@ again_locked:
                          */
                         run_ordered_completions(worker->workers, work);
 
-                        spin_lock_irq(&worker->lock);
-                        check_idle_worker(worker);
+                        check_pending_worker_creates(worker);
+
                 }
+
+                spin_lock_irq(&worker->lock);
+                check_idle_worker(worker);
+
                 if (freezing(current)) {
                         worker->working = 0;
                         spin_unlock_irq(&worker->lock);
@@ -216,8 +318,10 @@ again_locked:
                                 spin_lock_irq(&worker->lock);
                                 set_current_state(TASK_INTERRUPTIBLE);
                                 if (!list_empty(&worker->pending) ||
-                                    !list_empty(&worker->prio_pending))
-                                        goto again_locked;
+                                    !list_empty(&worker->prio_pending)) {
+                                        spin_unlock_irq(&worker->lock);
+                                        goto again;
+                                }
 
                                 /*
                                  * this makes sure we get a wakeup when someone
@@ -226,8 +330,13 @@ again_locked:
                                 worker->working = 0;
                                 spin_unlock_irq(&worker->lock);
 
-                                if (!kthread_should_stop())
-                                        schedule();
+                                if (!kthread_should_stop()) {
+                                        schedule_timeout(HZ * 120);
+                                        if (!worker->working &&
+                                            try_worker_shutdown(worker)) {
+                                                return 0;
+                                        }
+                                }
                         }
                         __set_current_state(TASK_RUNNING);
                 }
@@ -242,16 +351,30 @@ int btrfs_stop_workers(struct btrfs_workers *workers)
 {
         struct list_head *cur;
         struct btrfs_worker_thread *worker;
+        int can_stop;
 
+        spin_lock_irq(&workers->lock);
         list_splice_init(&workers->idle_list, &workers->worker_list);
         while (!list_empty(&workers->worker_list)) {
                 cur = workers->worker_list.next;
                 worker = list_entry(cur, struct btrfs_worker_thread,
                                     worker_list);
-                kthread_stop(worker->task);
-                list_del(&worker->worker_list);
-                kfree(worker);
+
+                atomic_inc(&worker->refs);
+                workers->num_workers -= 1;
+                if (!list_empty(&worker->worker_list)) {
+                        list_del_init(&worker->worker_list);
+                        put_worker(worker);
+                        can_stop = 1;
+                } else
+                        can_stop = 0;
+                spin_unlock_irq(&workers->lock);
+                if (can_stop)
+                        kthread_stop(worker->task);
+                spin_lock_irq(&workers->lock);
+                put_worker(worker);
         }
+        spin_unlock_irq(&workers->lock);
         return 0;
 }
 
@@ -266,10 +389,13 @@ void btrfs_init_workers(struct btrfs_workers *workers, char *name, int max)
         INIT_LIST_HEAD(&workers->order_list);
         INIT_LIST_HEAD(&workers->prio_order_list);
         spin_lock_init(&workers->lock);
+        spin_lock_init(&workers->order_lock);
         workers->max_workers = max;
         workers->idle_thresh = 32;
         workers->name = name;
         workers->ordered = 0;
+        workers->atomic_start_pending = 0;
+        workers->atomic_worker_start = 0;
 }
 
 /*
@@ -293,7 +419,9 @@ int btrfs_start_workers(struct btrfs_workers *workers, int num_workers)
                 INIT_LIST_HEAD(&worker->prio_pending);
                 INIT_LIST_HEAD(&worker->worker_list);
                 spin_lock_init(&worker->lock);
+
                 atomic_set(&worker->num_pending, 0);
+                atomic_set(&worker->refs, 1);
                 worker->workers = workers;
                 worker->task = kthread_run(worker_loop, worker,
                                            "btrfs-%s-%d", workers->name,
@@ -303,7 +431,6 @@ int btrfs_start_workers(struct btrfs_workers *workers, int num_workers)
                         kfree(worker);
                         goto fail;
                 }
-
                 spin_lock_irq(&workers->lock);
                 list_add_tail(&worker->worker_list, &workers->idle_list);
                 worker->idle = 1;
@@ -367,28 +494,18 @@ static struct btrfs_worker_thread *find_worker(struct btrfs_workers *workers)
 {
         struct btrfs_worker_thread *worker;
         unsigned long flags;
+        struct list_head *fallback;
 
 again:
         spin_lock_irqsave(&workers->lock, flags);
         worker = next_worker(workers);
-        spin_unlock_irqrestore(&workers->lock, flags);
 
         if (!worker) {
-                spin_lock_irqsave(&workers->lock, flags);
                 if (workers->num_workers >= workers->max_workers) {
-                        struct list_head *fallback = NULL;
-                        /*
-                         * we have failed to find any workers, just
-                         * return the force one
-                         */
-                        if (!list_empty(&workers->worker_list))
-                                fallback = workers->worker_list.next;
-                        if (!list_empty(&workers->idle_list))
-                                fallback = workers->idle_list.next;
-                        BUG_ON(!fallback);
-                        worker = list_entry(fallback,
-                                  struct btrfs_worker_thread, worker_list);
-                        spin_unlock_irqrestore(&workers->lock, flags);
+                        goto fallback;
+                } else if (workers->atomic_worker_start) {
+                        workers->atomic_start_pending = 1;
+                        goto fallback;
                 } else {
                         spin_unlock_irqrestore(&workers->lock, flags);
                         /* we're below the limit, start another worker */
@@ -396,6 +513,23 @@ again:
                         goto again;
                 }
         }
+        spin_unlock_irqrestore(&workers->lock, flags);
+        return worker;
+
+fallback:
+        fallback = NULL;
+        /*
+         * we have failed to find any workers, just
+         * return the first one we can find.
+         */
+        if (!list_empty(&workers->worker_list))
+                fallback = workers->worker_list.next;
+        if (!list_empty(&workers->idle_list))
+                fallback = workers->idle_list.next;
+        BUG_ON(!fallback);
+        worker = list_entry(fallback,
+                  struct btrfs_worker_thread, worker_list);
+        spin_unlock_irqrestore(&workers->lock, flags);
         return worker;
 }
 
@@ -435,9 +569,9 @@ int btrfs_requeue_work(struct btrfs_work *work)
                 worker->working = 1;
         }
 
-        spin_unlock_irqrestore(&worker->lock, flags);
         if (wake)
                 wake_up_process(worker->task);
+        spin_unlock_irqrestore(&worker->lock, flags);
 out:
 
         return 0;
@@ -463,14 +597,18 @@ int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
 
         worker = find_worker(workers);
         if (workers->ordered) {
-                spin_lock_irqsave(&workers->lock, flags);
+                /*
+                 * you're not allowed to do ordered queues from an
+                 * interrupt handler
+                 */
+                spin_lock(&workers->order_lock);
                 if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags)) {
                         list_add_tail(&work->order_list,
                                       &workers->prio_order_list);
                 } else {
                         list_add_tail(&work->order_list, &workers->order_list);
                 }
-                spin_unlock_irqrestore(&workers->lock, flags);
+                spin_unlock(&workers->order_lock);
         } else {
                 INIT_LIST_HEAD(&work->order_list);
         }
@@ -492,10 +630,10 @@ int btrfs_queue_worker(struct btrfs_workers *workers, struct btrfs_work *work)
                 wake = 1;
         worker->working = 1;
 
-        spin_unlock_irqrestore(&worker->lock, flags);
-
         if (wake)
                 wake_up_process(worker->task);
+        spin_unlock_irqrestore(&worker->lock, flags);
+
 out:
         return 0;
 }
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index 1b511c109db6..fc089b95ec14 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -73,6 +73,15 @@ struct btrfs_workers {
         /* force completions in the order they were queued */
         int ordered;
 
+        /* more workers required, but in an interrupt handler */
+        int atomic_start_pending;
+
+        /*
+         * are we allowed to sleep while starting workers or are we required
+         * to start them at a later time?
+         */
+        int atomic_worker_start;
+
         /* list with all the work threads.  The workers on the idle thread
          * may be actively servicing jobs, but they haven't yet hit the
          * idle thresh limit above.
@@ -90,6 +99,9 @@ struct btrfs_workers {
         /* lock for finding the next worker thread to queue on */
         spinlock_t lock;
 
+        /* lock for the ordered lists */
+        spinlock_t order_lock;
+
         /* extra name for this worker, used for current->name */
         char *name;
 };
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 9d8ba4d54a37..a11a32058b50 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -506,10 +506,10 @@ static noinline int add_ra_bio_pages(struct inode *inode,
                  */
                 set_page_extent_mapped(page);
                 lock_extent(tree, last_offset, end, GFP_NOFS);
-                spin_lock(&em_tree->lock);
+                read_lock(&em_tree->lock);
                 em = lookup_extent_mapping(em_tree, last_offset,
                                            PAGE_CACHE_SIZE);
-                spin_unlock(&em_tree->lock);
+                read_unlock(&em_tree->lock);
 
                 if (!em || last_offset < em->start ||
                     (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) ||
@@ -593,11 +593,11 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
         em_tree = &BTRFS_I(inode)->extent_tree;
 
         /* we need the actual starting offset of this extent in the file */
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree,
                                    page_offset(bio->bi_io_vec->bv_page),
                                    PAGE_CACHE_SIZE);
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
 
         compressed_len = em->block_len;
         cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 837435ce84ca..732d5b884aa7 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2290,7 +2290,7 @@ extern struct file_operations btrfs_file_operations;
 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct inode *inode,
                        u64 start, u64 end, u64 locked_end,
-                       u64 inline_limit, u64 *hint_block);
+                       u64 inline_limit, u64 *hint_block, int drop_cache);
 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
                               struct btrfs_root *root,
                               struct inode *inode, u64 start, u64 end);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index e83be2e4602c..253da7e01ab3 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -123,15 +123,15 @@ static struct extent_map *btree_get_extent(struct inode *inode,
         struct extent_map *em;
         int ret;
 
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree, start, len);
         if (em) {
                 em->bdev =
                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
-                spin_unlock(&em_tree->lock);
+                read_unlock(&em_tree->lock);
                 goto out;
         }
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
 
         em = alloc_extent_map(GFP_NOFS);
         if (!em) {
@@ -144,7 +144,7 @@ static struct extent_map *btree_get_extent(struct inode *inode,
         em->block_start = 0;
         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 
-        spin_lock(&em_tree->lock);
+        write_lock(&em_tree->lock);
         ret = add_extent_mapping(em_tree, em);
         if (ret == -EEXIST) {
                 u64 failed_start = em->start;
@@ -163,7 +163,7 @@ static struct extent_map *btree_get_extent(struct inode *inode,
                 free_extent_map(em);
                 em = NULL;
         }
-        spin_unlock(&em_tree->lock);
+        write_unlock(&em_tree->lock);
 
         if (ret)
                 em = ERR_PTR(ret);
@@ -1325,9 +1325,9 @@ static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
         offset = page_offset(page);
 
         em_tree = &BTRFS_I(inode)->extent_tree;
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
         if (!em) {
                 __unplug_io_fn(bdi, page);
                 return;
@@ -1698,7 +1698,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
                 err = -EINVAL;
                 goto fail_iput;
         }
-
+printk("thread pool is %d\n", fs_info->thread_pool_size);
         /*
          * we need to start all the end_io workers up front because the
          * queue work function gets called at interrupt time, and so it
@@ -1743,20 +1743,22 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         fs_info->endio_workers.idle_thresh = 4;
         fs_info->endio_meta_workers.idle_thresh = 4;
 
-        fs_info->endio_write_workers.idle_thresh = 64;
-        fs_info->endio_meta_write_workers.idle_thresh = 64;
+        fs_info->endio_write_workers.idle_thresh = 2;
+        fs_info->endio_meta_write_workers.idle_thresh = 2;
+
+        fs_info->endio_workers.atomic_worker_start = 1;
+        fs_info->endio_meta_workers.atomic_worker_start = 1;
+        fs_info->endio_write_workers.atomic_worker_start = 1;
+        fs_info->endio_meta_write_workers.atomic_worker_start = 1;
 
         btrfs_start_workers(&fs_info->workers, 1);
         btrfs_start_workers(&fs_info->submit_workers, 1);
         btrfs_start_workers(&fs_info->delalloc_workers, 1);
         btrfs_start_workers(&fs_info->fixup_workers, 1);
-        btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
-        btrfs_start_workers(&fs_info->endio_meta_workers,
-                            fs_info->thread_pool_size);
-        btrfs_start_workers(&fs_info->endio_meta_write_workers,
-                            fs_info->thread_pool_size);
-        btrfs_start_workers(&fs_info->endio_write_workers,
-                            fs_info->thread_pool_size);
+        btrfs_start_workers(&fs_info->endio_workers, 1);
+        btrfs_start_workers(&fs_info->endio_meta_workers, 1);
+        btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
+        btrfs_start_workers(&fs_info->endio_write_workers, 1);
 
         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 72a2b9c28e9f..edd86ae9e149 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5396,9 +5396,9 @@ static noinline int relocate_data_extent(struct inode *reloc_inode,
         lock_extent(&BTRFS_I(reloc_inode)->io_tree, start, end, GFP_NOFS);
         while (1) {
                 int ret;
-                spin_lock(&em_tree->lock);
+                write_lock(&em_tree->lock);
                 ret = add_extent_mapping(em_tree, em);
-                spin_unlock(&em_tree->lock);
+                write_unlock(&em_tree->lock);
                 if (ret != -EEXIST) {
                         free_extent_map(em);
                         break;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 68260180f587..a102422cd92e 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -367,10 +367,10 @@ static int insert_state(struct extent_io_tree *tree,
         }
         if (bits & EXTENT_DIRTY)
                 tree->dirty_bytes += end - start + 1;
-        set_state_cb(tree, state, bits);
-        state->state |= bits;
         state->start = start;
         state->end = end;
+        set_state_cb(tree, state, bits);
+        state->state |= bits;
         node = tree_insert(&tree->state, end, &state->rb_node);
         if (node) {
                 struct extent_state *found;
@@ -471,10 +471,14 @@ static int clear_state_bit(struct extent_io_tree *tree,
  * bits were already set, or zero if none of the bits were already set.
  */
 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
-                     int bits, int wake, int delete, gfp_t mask)
+                     int bits, int wake, int delete,
+                     struct extent_state **cached_state,
+                     gfp_t mask)
 {
         struct extent_state *state;
+        struct extent_state *cached;
         struct extent_state *prealloc = NULL;
+        struct rb_node *next_node;
         struct rb_node *node;
         u64 last_end;
         int err;
@@ -488,6 +492,17 @@ again:
         }
 
         spin_lock(&tree->lock);
+        if (cached_state) {
+                cached = *cached_state;
+                *cached_state = NULL;
+                if (cached->tree && cached->start == start) {
+                        atomic_dec(&cached->refs);
+                        state = cached;
+                        last_end = state->end;
+                        goto found;
+                }
+                free_extent_state(cached);
+        }
         /*
          * this search will find the extents that end after
          * our range starts
@@ -496,6 +511,7 @@ again:
         if (!node)
                 goto out;
         state = rb_entry(node, struct extent_state, rb_node);
+hit_next:
         if (state->start > end)
                 goto out;
         WARN_ON(state->end < start);
@@ -555,11 +571,21 @@ again:
                 prealloc = NULL;
                 goto out;
         }
-
+found:
+        if (state->end < end && prealloc && !need_resched())
+                next_node = rb_next(&state->rb_node);
+        else
+                next_node = NULL;
         set |= clear_state_bit(tree, state, bits, wake, delete);
         if (last_end == (u64)-1)
                 goto out;
         start = last_end + 1;
+        if (start <= end && next_node) {
+                state = rb_entry(next_node, struct extent_state,
+                                 rb_node);
+                if (state->start == start)
+                        goto hit_next;
+        }
         goto search_again;
 
 out:
@@ -653,26 +679,37 @@ static void set_state_bits(struct extent_io_tree *tree,
         state->state |= bits;
 }
 
+static void cache_state(struct extent_state *state,
+                        struct extent_state **cached_ptr)
+{
+        if (cached_ptr && !(*cached_ptr)) {
+                if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {
+                        *cached_ptr = state;
+                        atomic_inc(&state->refs);
+                }
+        }
+}
+
 /*
- * set some bits on a range in the tree.  This may require allocations
- * or sleeping, so the gfp mask is used to indicate what is allowed.
+ * set some bits on a range in the tree.  This may require allocations or
+ * sleeping, so the gfp mask is used to indicate what is allowed.
  *
- * If 'exclusive' == 1, this will fail with -EEXIST if some part of the
- * range already has the desired bits set.  The start of the existing
- * range is returned in failed_start in this case.
+ * If any of the exclusive bits are set, this will fail with -EEXIST if some
+ * part of the range already has the desired bits set.  The start of the
+ * existing range is returned in failed_start in this case.
  *
- * [start, end] is inclusive
- * This takes the tree lock.
+ * [start, end] is inclusive This takes the tree lock.
  */
+
 static int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
-                          int bits, int exclusive, u64 *failed_start,
+                          int bits, int exclusive_bits, u64 *failed_start,
+                          struct extent_state **cached_state,
                           gfp_t mask)
 {
         struct extent_state *state;
         struct extent_state *prealloc = NULL;
         struct rb_node *node;
         int err = 0;
-        int set;
         u64 last_start;
         u64 last_end;
 again:
@@ -683,6 +720,13 @@ again:
         }
 
         spin_lock(&tree->lock);
+        if (cached_state && *cached_state) {
+                state = *cached_state;
+                if (state->start == start && state->tree) {
+                        node = &state->rb_node;
+                        goto hit_next;
+                }
+        }
         /*
          * this search will find all the extents that end after
          * our range starts.
@@ -694,8 +738,8 @@ again:
                 BUG_ON(err == -EEXIST);
                 goto out;
         }
-
         state = rb_entry(node, struct extent_state, rb_node);
+hit_next:
         last_start = state->start;
         last_end = state->end;
 
@@ -706,17 +750,28 @@ again:
          * Just lock what we found and keep going
          */
         if (state->start == start && state->end <= end) {
-                set = state->state & bits;
-                if (set && exclusive) {
+                struct rb_node *next_node;
+                if (state->state & exclusive_bits) {
                         *failed_start = state->start;
                         err = -EEXIST;
                         goto out;
                 }
                 set_state_bits(tree, state, bits);
+                cache_state(state, cached_state);
                 merge_state(tree, state);
                 if (last_end == (u64)-1)
                         goto out;
+
                 start = last_end + 1;
+                if (start < end && prealloc && !need_resched()) {
+                        next_node = rb_next(node);
+                        if (next_node) {
+                                state = rb_entry(next_node, struct extent_state,
+                                                 rb_node);
+                                if (state->start == start)
+                                        goto hit_next;
+                        }
+                }
                 goto search_again;
         }
 
@@ -737,8 +792,7 @@ again:
          * desired bit on it.
          */
         if (state->start < start) {
-                set = state->state & bits;
-                if (exclusive && set) {
+                if (state->state & exclusive_bits) {
                         *failed_start = start;
                         err = -EEXIST;
                         goto out;
@@ -750,6 +804,7 @@ again:
                         goto out;
                 if (state->end <= end) {
                         set_state_bits(tree, state, bits);
+                        cache_state(state, cached_state);
                         merge_state(tree, state);
                         if (last_end == (u64)-1)
                                 goto out;
@@ -774,6 +829,7 @@ again:
                         this_end = last_start - 1;
                 err = insert_state(tree, prealloc, start, this_end,
                                    bits);
+                cache_state(prealloc, cached_state);
                 prealloc = NULL;
                 BUG_ON(err == -EEXIST);
                 if (err)
@@ -788,8 +844,7 @@ again:
          * on the first half
          */
         if (state->start <= end && state->end > end) {
-                set = state->state & bits;
-                if (exclusive && set) {
+                if (state->state & exclusive_bits) {
                         *failed_start = start;
                         err = -EEXIST;
                         goto out;
@@ -798,6 +853,7 @@ again:
                 BUG_ON(err == -EEXIST);
 
                 set_state_bits(tree, prealloc, bits);
+                cache_state(prealloc, cached_state);
                 merge_state(tree, prealloc);
                 prealloc = NULL;
                 goto out;
@@ -826,86 +882,64 @@ int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
                      gfp_t mask)
 {
         return set_extent_bit(tree, start, end, EXTENT_DIRTY, 0, NULL,
-                              mask);
-}
-
-int set_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
-                       gfp_t mask)
-{
-        return set_extent_bit(tree, start, end, EXTENT_ORDERED, 0, NULL, mask);
+                              NULL, mask);
 }
 
 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
                     int bits, gfp_t mask)
 {
         return set_extent_bit(tree, start, end, bits, 0, NULL,
-                              mask);
+                              NULL, mask);
 }
 
 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
                       int bits, gfp_t mask)
 {
-        return clear_extent_bit(tree, start, end, bits, 0, 0, mask);
+        return clear_extent_bit(tree, start, end, bits, 0, 0, NULL, mask);
 }
 
 int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end,
                      gfp_t mask)
 {
         return set_extent_bit(tree, start, end,
-                              EXTENT_DELALLOC | EXTENT_DIRTY,
-                              0, NULL, mask);
+                              EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE,
+                              0, NULL, NULL, mask);
 }
 
 int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
                        gfp_t mask)
 {
         return clear_extent_bit(tree, start, end,
-                                EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, mask);
-}
-
-int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
-                         gfp_t mask)
-{
-        return clear_extent_bit(tree, start, end, EXTENT_ORDERED, 1, 0, mask);
+                                EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
+                                NULL, mask);
 }
 
 int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
                      gfp_t mask)
 {
         return set_extent_bit(tree, start, end, EXTENT_NEW, 0, NULL,
-                              mask);
+                              NULL, mask);
 }
 
 static int clear_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
                        gfp_t mask)
 {
-        return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0, mask);
+        return clear_extent_bit(tree, start, end, EXTENT_NEW, 0, 0,
+                                NULL, mask);
 }
 
 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
                         gfp_t mask)
 {
         return set_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, NULL,
-                              mask);
+                              NULL, mask);
 }
 
 static int clear_extent_uptodate(struct extent_io_tree *tree, u64 start,
                                  u64 end, gfp_t mask)
 {
-        return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0, mask);
-}
-
-static int set_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end,
-                         gfp_t mask)
-{
-        return set_extent_bit(tree, start, end, EXTENT_WRITEBACK,
-                              0, NULL, mask);
-}
-
-static int clear_extent_writeback(struct extent_io_tree *tree, u64 start,
-                                  u64 end, gfp_t mask)
-{
-        return clear_extent_bit(tree, start, end, EXTENT_WRITEBACK, 1, 0, mask);
+        return clear_extent_bit(tree, start, end, EXTENT_UPTODATE, 0, 0,
+                                NULL, mask);
 }
 
 int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
@@ -917,13 +951,15 @@ int wait_on_extent_writeback(struct extent_io_tree *tree, u64 start, u64 end)
  * either insert or lock state struct between start and end use mask to tell
  * us if waiting is desired.
  */
-int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
+int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
+                     int bits, struct extent_state **cached_state, gfp_t mask)
 {
         int err;
         u64 failed_start;
         while (1) {
-                err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
-                                     &failed_start, mask);
+                err = set_extent_bit(tree, start, end, EXTENT_LOCKED | bits,
+                                     EXTENT_LOCKED, &failed_start,
+                                     cached_state, mask);
                 if (err == -EEXIST && (mask & __GFP_WAIT)) {
                         wait_extent_bit(tree, failed_start, end, EXTENT_LOCKED);
                         start = failed_start;
@@ -935,27 +971,40 @@ int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
         return err;
 }
 
+int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask)
+{
+        return lock_extent_bits(tree, start, end, 0, NULL, mask);
+}
+
 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
                     gfp_t mask)
 {
         int err;
         u64 failed_start;
 
-        err = set_extent_bit(tree, start, end, EXTENT_LOCKED, 1,
-                             &failed_start, mask);
+        err = set_extent_bit(tree, start, end, EXTENT_LOCKED, EXTENT_LOCKED,
+                             &failed_start, NULL, mask);
         if (err == -EEXIST) {
                 if (failed_start > start)
                         clear_extent_bit(tree, start, failed_start - 1,
-                                         EXTENT_LOCKED, 1, 0, mask);
+                                         EXTENT_LOCKED, 1, 0, NULL, mask);
                 return 0;
         }
         return 1;
 }
 
+int unlock_extent_cached(struct extent_io_tree *tree, u64 start, u64 end,
+                         struct extent_state **cached, gfp_t mask)
+{
+        return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, cached,
+                                mask);
+}
+
 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end,
                   gfp_t mask)
 {
-        return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, mask);
+        return clear_extent_bit(tree, start, end, EXTENT_LOCKED, 1, 0, NULL,
+                                mask);
 }
 
 /*
@@ -974,7 +1023,6 @@ int set_range_dirty(struct extent_io_tree *tree, u64 start, u64 end)
                 page_cache_release(page);
                 index++;
         }
-        set_extent_dirty(tree, start, end, GFP_NOFS);
         return 0;
 }
 
@@ -994,7 +1042,6 @@ static int set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
                 page_cache_release(page);
                 index++;
         }
-        set_extent_writeback(tree, start, end, GFP_NOFS);
         return 0;
 }
 
@@ -1232,6 +1279,7 @@ static noinline u64 find_lock_delalloc_range(struct inode *inode,
         u64 delalloc_start;
         u64 delalloc_end;
         u64 found;
+        struct extent_state *cached_state = NULL;
         int ret;
         int loops = 0;
 
@@ -1269,6 +1317,7 @@ again:
                 /* some of the pages are gone, lets avoid looping by
                  * shortening the size of the delalloc range we're searching
                  */
+                free_extent_state(cached_state);
                 if (!loops) {
                         unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
                         max_bytes = PAGE_CACHE_SIZE - offset;
@@ -1282,18 +1331,21 @@ again:
         BUG_ON(ret);
 
         /* step three, lock the state bits for the whole range */
-        lock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
+        lock_extent_bits(tree, delalloc_start, delalloc_end,
+                         0, &cached_state, GFP_NOFS);
 
         /* then test to make sure it is all still delalloc */
         ret = test_range_bit(tree, delalloc_start, delalloc_end,
-                             EXTENT_DELALLOC, 1);
+                             EXTENT_DELALLOC, 1, cached_state);
         if (!ret) {
-                unlock_extent(tree, delalloc_start, delalloc_end, GFP_NOFS);
+                unlock_extent_cached(tree, delalloc_start, delalloc_end,
+                                     &cached_state, GFP_NOFS);
                 __unlock_for_delalloc(inode, locked_page,
                               delalloc_start, delalloc_end);
                 cond_resched();
                 goto again;
         }
+        free_extent_state(cached_state);
         *start = delalloc_start;
         *end = delalloc_end;
 out_failed:
@@ -1307,7 +1359,8 @@ int extent_clear_unlock_delalloc(struct inode *inode,
                                 int clear_unlock,
                                 int clear_delalloc, int clear_dirty,
                                 int set_writeback,
-                                int end_writeback)
+                                int end_writeback,
+                                int set_private2)
 {
         int ret;
         struct page *pages[16];
@@ -1325,8 +1378,9 @@ int extent_clear_unlock_delalloc(struct inode *inode,
         if (clear_delalloc)
                 clear_bits |= EXTENT_DELALLOC;
 
-        clear_extent_bit(tree, start, end, clear_bits, 1, 0, GFP_NOFS);
-        if (!(unlock_pages || clear_dirty || set_writeback || end_writeback))
+        clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
+        if (!(unlock_pages || clear_dirty || set_writeback || end_writeback ||
+              set_private2))
                 return 0;
 
         while (nr_pages > 0) {
@@ -1334,6 +1388,10 @@ int extent_clear_unlock_delalloc(struct inode *inode,
                                      min_t(unsigned long,
                                      nr_pages, ARRAY_SIZE(pages)), pages);
                 for (i = 0; i < ret; i++) {
+
+                        if (set_private2)
+                                SetPagePrivate2(pages[i]);
+
                         if (pages[i] == locked_page) {
                                 page_cache_release(pages[i]);
                                 continue;
@@ -1476,14 +1534,17 @@ out:
  * range is found set.
  */
 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
-                   int bits, int filled)
+                   int bits, int filled, struct extent_state *cached)
 {
         struct extent_state *state = NULL;
         struct rb_node *node;
         int bitset = 0;
 
         spin_lock(&tree->lock);
-        node = tree_search(tree, start);
+        if (cached && cached->tree && cached->start == start)
+                node = &cached->rb_node;
+        else
+                node = tree_search(tree, start);
         while (node && start <= end) {
                 state = rb_entry(node, struct extent_state, rb_node);
 
@@ -1526,7 +1587,7 @@ static int check_page_uptodate(struct extent_io_tree *tree,
 {
         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
         u64 end = start + PAGE_CACHE_SIZE - 1;
-        if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1))
+        if (test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL))
                 SetPageUptodate(page);
         return 0;
 }
@@ -1540,7 +1601,7 @@ static int check_page_locked(struct extent_io_tree *tree,
 {
         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
         u64 end = start + PAGE_CACHE_SIZE - 1;
-        if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0))
+        if (!test_range_bit(tree, start, end, EXTENT_LOCKED, 0, NULL))
                 unlock_page(page);
         return 0;
 }
@@ -1552,10 +1613,7 @@ static int check_page_locked(struct extent_io_tree *tree,
 static int check_page_writeback(struct extent_io_tree *tree,
                              struct page *page)
 {
-        u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
-        u64 end = start + PAGE_CACHE_SIZE - 1;
-        if (!test_range_bit(tree, start, end, EXTENT_WRITEBACK, 0))
-                end_page_writeback(page);
+        end_page_writeback(page);
         return 0;
 }
 
@@ -1613,13 +1671,11 @@ static void end_bio_extent_writepage(struct bio *bio, int err)
                 }
 
                 if (!uptodate) {
-                        clear_extent_uptodate(tree, start, end, GFP_ATOMIC);
+                        clear_extent_uptodate(tree, start, end, GFP_NOFS);
                         ClearPageUptodate(page);
                         SetPageError(page);
                 }
 
-                clear_extent_writeback(tree, start, end, GFP_ATOMIC);
-
                 if (whole_page)
                         end_page_writeback(page);
                 else
@@ -1983,7 +2039,8 @@ static int __extent_read_full_page(struct extent_io_tree *tree,
                         continue;
                 }
                 /* the get_extent function already copied into the page */
-                if (test_range_bit(tree, cur, cur_end, EXTENT_UPTODATE, 1)) {
+                if (test_range_bit(tree, cur, cur_end,
+                                   EXTENT_UPTODATE, 1, NULL)) {
                         check_page_uptodate(tree, page);
                         unlock_extent(tree, cur, cur + iosize - 1, GFP_NOFS);
                         cur = cur + iosize;
@@ -2078,6 +2135,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         u64 iosize;
         u64 unlock_start;
         sector_t sector;
+        struct extent_state *cached_state = NULL;
         struct extent_map *em;
         struct block_device *bdev;
         int ret;
@@ -2124,6 +2182,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         delalloc_end = 0;
         page_started = 0;
         if (!epd->extent_locked) {
+                u64 delalloc_to_write;
                 /*
                  * make sure the wbc mapping index is at least updated
                  * to this page.
@@ -2143,6 +2202,14 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                         tree->ops->fill_delalloc(inode, page, delalloc_start,
                                                  delalloc_end, &page_started,
                                                  &nr_written);
+                        delalloc_to_write = (delalloc_end -
+                                        max_t(u64, page_offset(page),
+                                              delalloc_start) + 1) >>
+                                        PAGE_CACHE_SHIFT;
+                        if (wbc->nr_to_write < delalloc_to_write) {
+                                wbc->nr_to_write = min_t(long, 8192,
+                                                 delalloc_to_write);
+                        }
                         delalloc_start = delalloc_end + 1;
                 }
 
@@ -2160,15 +2227,10 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                         goto done_unlocked;
                 }
         }
-        lock_extent(tree, start, page_end, GFP_NOFS);
-
-        unlock_start = start;
-
         if (tree->ops && tree->ops->writepage_start_hook) {
                 ret = tree->ops->writepage_start_hook(page, start,
                                                       page_end);
                 if (ret == -EAGAIN) {
-                        unlock_extent(tree, start, page_end, GFP_NOFS);
                         redirty_page_for_writepage(wbc, page);
                         update_nr_written(page, wbc, nr_written);
                         unlock_page(page);
@@ -2184,12 +2246,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
         update_nr_written(page, wbc, nr_written + 1);
 
         end = page_end;
-        if (test_range_bit(tree, start, page_end, EXTENT_DELALLOC, 0))
-                printk(KERN_ERR "btrfs delalloc bits after lock_extent\n");
-
         if (last_byte <= start) {
-                clear_extent_dirty(tree, start, page_end, GFP_NOFS);
-                unlock_extent(tree, start, page_end, GFP_NOFS);
                 if (tree->ops && tree->ops->writepage_end_io_hook)
                         tree->ops->writepage_end_io_hook(page, start,
                                                          page_end, NULL, 1);
@@ -2197,13 +2254,10 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                 goto done;
         }
 
-        set_extent_uptodate(tree, start, page_end, GFP_NOFS);
         blocksize = inode->i_sb->s_blocksize;
 
         while (cur <= end) {
                 if (cur >= last_byte) {
-                        clear_extent_dirty(tree, cur, page_end, GFP_NOFS);
-                        unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
                         if (tree->ops && tree->ops->writepage_end_io_hook)
                                 tree->ops->writepage_end_io_hook(page, cur,
                                                          page_end, NULL, 1);
@@ -2235,12 +2289,6 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                  */
                 if (compressed || block_start == EXTENT_MAP_HOLE ||
                     block_start == EXTENT_MAP_INLINE) {
-                        clear_extent_dirty(tree, cur,
-                                           cur + iosize - 1, GFP_NOFS);
-
-                        unlock_extent(tree, unlock_start, cur + iosize - 1,
-                                      GFP_NOFS);
-
                         /*
                          * end_io notification does not happen here for
                          * compressed extents
@@ -2265,13 +2313,12 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
                 }
                 /* leave this out until we have a page_mkwrite call */
                 if (0 && !test_range_bit(tree, cur, cur + iosize - 1,
-                                   EXTENT_DIRTY, 0)) {
+                                   EXTENT_DIRTY, 0, NULL)) {
                         cur = cur + iosize;
                         pg_offset += iosize;
                         continue;
                 }
 
-                clear_extent_dirty(tree, cur, cur + iosize - 1, GFP_NOFS);
                 if (tree->ops && tree->ops->writepage_io_hook) {
                         ret = tree->ops->writepage_io_hook(page, cur,
                                                 cur + iosize - 1);
@@ -2309,12 +2356,12 @@ done:
                 set_page_writeback(page);
                 end_page_writeback(page);
         }
-        if (unlock_start <= page_end)
-                unlock_extent(tree, unlock_start, page_end, GFP_NOFS);
         unlock_page(page);
 
 done_unlocked:
 
+        /* drop our reference on any cached states */
+        free_extent_state(cached_state);
         return 0;
 }
 
@@ -2339,7 +2386,6 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
                              writepage_t writepage, void *data,
                              void (*flush_fn)(void *))
 {
-        struct backing_dev_info *bdi = mapping->backing_dev_info;
         int ret = 0;
         int done = 0;
         struct pagevec pvec;
@@ -2414,10 +2460,6 @@ retry:
                         }
                         if (ret || wbc->nr_to_write <= 0)
                                 done = 1;
-                        if (wbc->nonblocking && bdi_write_congested(bdi)) {
-                                wbc->encountered_congestion = 1;
-                                done = 1;
-                        }
                 }
                 pagevec_release(&pvec);
                 cond_resched();
@@ -2604,10 +2646,10 @@ int extent_invalidatepage(struct extent_io_tree *tree,
                 return 0;
 
         lock_extent(tree, start, end, GFP_NOFS);
-        wait_on_extent_writeback(tree, start, end);
+        wait_on_page_writeback(page);
         clear_extent_bit(tree, start, end,
                          EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
-                         1, 1, GFP_NOFS);
+                         1, 1, NULL, GFP_NOFS);
         return 0;
 }
 
@@ -2687,7 +2729,7 @@ int extent_prepare_write(struct extent_io_tree *tree,
                     !isnew && !PageUptodate(page) &&
                     (block_off_end > to || block_off_start < from) &&
                     !test_range_bit(tree, block_start, cur_end,
-                                    EXTENT_UPTODATE, 1)) {
+                                    EXTENT_UPTODATE, 1, NULL)) {
                         u64 sector;
                         u64 extent_offset = block_start - em->start;
                         size_t iosize;
@@ -2701,7 +2743,7 @@ int extent_prepare_write(struct extent_io_tree *tree,
                          */
                         set_extent_bit(tree, block_start,
                                        block_start + iosize - 1,
-                                       EXTENT_LOCKED, 0, NULL, GFP_NOFS);
+                                       EXTENT_LOCKED, 0, NULL, NULL, GFP_NOFS);
                         ret = submit_extent_page(READ, tree, page,
                                          sector, iosize, page_offset, em->bdev,
                                          NULL, 1,
@@ -2742,13 +2784,13 @@ int try_release_extent_state(struct extent_map_tree *map,
         int ret = 1;
 
         if (test_range_bit(tree, start, end,
-                           EXTENT_IOBITS | EXTENT_ORDERED, 0))
+                           EXTENT_IOBITS, 0, NULL))
                 ret = 0;
         else {
                 if ((mask & GFP_NOFS) == GFP_NOFS)
                         mask = GFP_NOFS;
                 clear_extent_bit(tree, start, end, EXTENT_UPTODATE,
-                                 1, 1, mask);
+                                 1, 1, NULL, mask);
         }
         return ret;
 }
@@ -2771,29 +2813,28 @@ int try_release_extent_mapping(struct extent_map_tree *map,
                 u64 len;
                 while (start <= end) {
                         len = end - start + 1;
-                        spin_lock(&map->lock);
+                        write_lock(&map->lock);
                         em = lookup_extent_mapping(map, start, len);
                         if (!em || IS_ERR(em)) {
-                                spin_unlock(&map->lock);
+                                write_unlock(&map->lock);
                                 break;
                         }
                         if (test_bit(EXTENT_FLAG_PINNED, &em->flags) ||
                             em->start != start) {
-                                spin_unlock(&map->lock);
+                                write_unlock(&map->lock);
                                 free_extent_map(em);
                                 break;
                         }
                         if (!test_range_bit(tree, em->start,
                                             extent_map_end(em) - 1,
-                                            EXTENT_LOCKED | EXTENT_WRITEBACK |
-                                            EXTENT_ORDERED,
-                                            0)) {
+                                            EXTENT_LOCKED | EXTENT_WRITEBACK,
+                                            0, NULL)) {
                                 remove_extent_mapping(map, em);
                                 /* once for the rb tree */
                                 free_extent_map(em);
                         }
                         start = extent_map_end(em);
-                        spin_unlock(&map->lock);
+                        write_unlock(&map->lock);
 
                         /* once for us */
                         free_extent_map(em);
@@ -3203,7 +3244,7 @@ int extent_range_uptodate(struct extent_io_tree *tree,
         int uptodate;
         unsigned long index;
 
-        ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
+        ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1, NULL);
         if (ret)
                 return 1;
         while (start <= end) {
@@ -3233,7 +3274,7 @@ int extent_buffer_uptodate(struct extent_io_tree *tree,
                 return 1;
 
         ret = test_range_bit(tree, eb->start, eb->start + eb->len - 1,
-                           EXTENT_UPTODATE, 1);
+                           EXTENT_UPTODATE, 1, NULL);
         if (ret)
                 return ret;
 
@@ -3269,7 +3310,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
                 return 0;
 
         if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
-                           EXTENT_UPTODATE, 1)) {
+                           EXTENT_UPTODATE, 1, NULL)) {
                 return 0;
         }
 
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 5bc20abf3f3d..14ed16fd862d 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -13,10 +13,8 @@
 #define EXTENT_DEFRAG (1 << 6)
 #define EXTENT_DEFRAG_DONE (1 << 7)
 #define EXTENT_BUFFER_FILLED (1 << 8)
-#define EXTENT_ORDERED (1 << 9)
-#define EXTENT_ORDERED_METADATA (1 << 10)
-#define EXTENT_BOUNDARY (1 << 11)
-#define EXTENT_NODATASUM (1 << 12)
+#define EXTENT_BOUNDARY (1 << 9)
+#define EXTENT_NODATASUM (1 << 10)
 #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK)
 
 /* flags for bio submission */
@@ -142,6 +140,8 @@ int try_release_extent_state(struct extent_map_tree *map,
                              struct extent_io_tree *tree, struct page *page,
                              gfp_t mask);
 int lock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);
+int lock_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
+                     int bits, struct extent_state **cached, gfp_t mask);
 int unlock_extent(struct extent_io_tree *tree, u64 start, u64 end, gfp_t mask);
 int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end,
                     gfp_t mask);
@@ -155,11 +155,12 @@ u64 count_range_bits(struct extent_io_tree *tree,
                      u64 max_bytes, unsigned long bits);
 
 int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
-                   int bits, int filled);
+                   int bits, int filled, struct extent_state *cached_state);
 int clear_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
                       int bits, gfp_t mask);
 int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
-                     int bits, int wake, int delete, gfp_t mask);
+                     int bits, int wake, int delete, struct extent_state **cached,
+                     gfp_t mask);
 int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
                     int bits, gfp_t mask);
 int set_extent_uptodate(struct extent_io_tree *tree, u64 start, u64 end,
@@ -282,5 +283,6 @@ int extent_clear_unlock_delalloc(struct inode *inode,
                                 int clear_unlock,
                                 int clear_delalloc, int clear_dirty,
                                 int set_writeback,
-                                int end_writeback);
+                                int end_writeback,
+                                int set_private2);
 #endif
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 30c9365861e6..5bc7a0d325e7 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -36,7 +36,7 @@ void extent_map_exit(void)
 void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask)
 {
         tree->map.rb_node = NULL;
-        spin_lock_init(&tree->lock);
+        rwlock_init(&tree->lock);
 }
 
 /**
@@ -198,6 +198,56 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next)
         return 0;
 }
 
+int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
+{
+        int ret = 0;
+        struct extent_map *merge = NULL;
+        struct rb_node *rb;
+        struct extent_map *em;
+
+        write_lock(&tree->lock);
+        em = lookup_extent_mapping(tree, start, len);
+
+        WARN_ON(em->start != start || !em);
+
+        if (!em)
+                goto out;
+
+        clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+
+        if (em->start != 0) {
+                rb = rb_prev(&em->rb_node);
+                if (rb)
+                        merge = rb_entry(rb, struct extent_map, rb_node);
+                if (rb && mergable_maps(merge, em)) {
+                        em->start = merge->start;
+                        em->len += merge->len;
+                        em->block_len += merge->block_len;
+                        em->block_start = merge->block_start;
+                        merge->in_tree = 0;
+                        rb_erase(&merge->rb_node, &tree->map);
+                        free_extent_map(merge);
+                }
+        }
+
+        rb = rb_next(&em->rb_node);
+        if (rb)
+                merge = rb_entry(rb, struct extent_map, rb_node);
+        if (rb && mergable_maps(em, merge)) {
+                em->len += merge->len;
+                em->block_len += merge->len;
+                rb_erase(&merge->rb_node, &tree->map);
+                merge->in_tree = 0;
+                free_extent_map(merge);
+        }
+
+        free_extent_map(em);
+out:
+        write_unlock(&tree->lock);
+        return ret;
+
+}
+
 /**
  * add_extent_mapping - add new extent map to the extent tree
  * @tree:       tree to insert new map in
@@ -222,7 +272,6 @@ int add_extent_mapping(struct extent_map_tree *tree,
                 ret = -EEXIST;
                 goto out;
         }
-        assert_spin_locked(&tree->lock);
         rb = tree_insert(&tree->map, em->start, &em->rb_node);
         if (rb) {
                 ret = -EEXIST;
@@ -285,7 +334,6 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
         struct rb_node *next = NULL;
         u64 end = range_end(start, len);
 
-        assert_spin_locked(&tree->lock);
         rb_node = __tree_search(&tree->map, start, &prev, &next);
         if (!rb_node && prev) {
                 em = rb_entry(prev, struct extent_map, rb_node);
@@ -331,7 +379,6 @@ int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
         int ret = 0;
 
         WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
-        assert_spin_locked(&tree->lock);
         rb_erase(&em->rb_node, &tree->map);
         em->in_tree = 0;
         return ret;
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index fb6eeef06bb0..d3d442f4bbbd 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -31,7 +31,7 @@ struct extent_map {
 
 struct extent_map_tree {
         struct rb_root map;
-        spinlock_t lock;
+        rwlock_t lock;
 };
 
 static inline u64 extent_map_end(struct extent_map *em)
@@ -59,4 +59,5 @@ struct extent_map *alloc_extent_map(gfp_t mask);
 void free_extent_map(struct extent_map *em);
 int __init extent_map_init(void);
 void extent_map_exit(void);
+int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len);
 #endif
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 4b833972273a..571ad3c13b47 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -112,8 +112,6 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
         int err = 0;
         int i;
         struct inode *inode = fdentry(file)->d_inode;
-        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
-        u64 hint_byte;
         u64 num_bytes;
         u64 start_pos;
         u64 end_of_last_block;
@@ -125,22 +123,6 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 
         end_of_last_block = start_pos + num_bytes - 1;
-
-        lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
-        trans = btrfs_join_transaction(root, 1);
-        if (!trans) {
-                err = -ENOMEM;
-                goto out_unlock;
-        }
-        btrfs_set_trans_block_group(trans, inode);
-        hint_byte = 0;
-
-        set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
-
-        /* check for reserved extents on each page, we don't want
-         * to reset the delalloc bit on things that already have
-         * extents reserved.
-         */
         btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
         for (i = 0; i < num_pages; i++) {
                 struct page *p = pages[i];
@@ -155,9 +137,6 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                  * at this time.
                  */
         }
-        err = btrfs_end_transaction(trans, root);
-out_unlock:
-        unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
         return err;
 }
 
@@ -189,18 +168,18 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                 if (!split2)
                         split2 = alloc_extent_map(GFP_NOFS);
 
-                spin_lock(&em_tree->lock);
+                write_lock(&em_tree->lock);
                 em = lookup_extent_mapping(em_tree, start, len);
                 if (!em) {
-                        spin_unlock(&em_tree->lock);
+                        write_unlock(&em_tree->lock);
                         break;
                 }
                 flags = em->flags;
                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
-                        spin_unlock(&em_tree->lock);
                         if (em->start <= start &&
                             (!testend || em->start + em->len >= start + len)) {
                                 free_extent_map(em);
+                                write_unlock(&em_tree->lock);
                                 break;
                         }
                         if (start < em->start) {
@@ -210,6 +189,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                                 start = em->start + em->len;
                         }
                         free_extent_map(em);
+                        write_unlock(&em_tree->lock);
                         continue;
                 }
                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
@@ -260,7 +240,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                         free_extent_map(split);
                         split = NULL;
                 }
-                spin_unlock(&em_tree->lock);
+                write_unlock(&em_tree->lock);
 
                 /* once for us */
                 free_extent_map(em);
@@ -289,7 +269,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct inode *inode,
                        u64 start, u64 end, u64 locked_end,
-                       u64 inline_limit, u64 *hint_byte)
+                       u64 inline_limit, u64 *hint_byte, int drop_cache)
 {
         u64 extent_end = 0;
         u64 search_start = start;
@@ -314,7 +294,8 @@ noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
         int ret;
 
         inline_limit = 0;
-        btrfs_drop_extent_cache(inode, start, end - 1, 0);
+        if (drop_cache)
+                btrfs_drop_extent_cache(inode, start, end - 1, 0);
 
         path = btrfs_alloc_path();
         if (!path)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 59cba180fe83..941f1b71cd22 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -231,7 +231,8 @@ static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
         }
 
         ret = btrfs_drop_extents(trans, root, inode, start,
-                                 aligned_end, aligned_end, start, &hint_byte);
+                                 aligned_end, aligned_end, start,
+                                 &hint_byte, 1);
         BUG_ON(ret);
 
         if (isize > actual_end)
@@ -240,7 +241,7 @@ static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
                                    inline_len, compressed_size,
                                    compressed_pages);
         BUG_ON(ret);
-        btrfs_drop_extent_cache(inode, start, aligned_end, 0);
+        btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
         return 0;
 }
 
@@ -425,7 +426,7 @@ again:
                         extent_clear_unlock_delalloc(inode,
                                                      &BTRFS_I(inode)->io_tree,
                                                      start, end, NULL, 1, 0,
-                                                     0, 1, 1, 1);
+                                                     0, 1, 1, 1, 0);
                         ret = 0;
                         goto free_pages_out;
                 }
@@ -611,9 +612,9 @@ static noinline int submit_compressed_extents(struct inode *inode,
                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 
                 while (1) {
-                        spin_lock(&em_tree->lock);
+                        write_lock(&em_tree->lock);
                         ret = add_extent_mapping(em_tree, em);
-                        spin_unlock(&em_tree->lock);
+                        write_unlock(&em_tree->lock);
                         if (ret != -EEXIST) {
                                 free_extent_map(em);
                                 break;
@@ -640,7 +641,7 @@ static noinline int submit_compressed_extents(struct inode *inode,
                                              async_extent->start,
                                              async_extent->start +
                                              async_extent->ram_size - 1,
-                                             NULL, 1, 1, 0, 1, 1, 0);
+                                             NULL, 1, 1, 0, 1, 1, 0, 0);
 
                 ret = btrfs_submit_compressed_write(inode,
                                     async_extent->start,
@@ -713,7 +714,7 @@ static noinline int cow_file_range(struct inode *inode,
                         extent_clear_unlock_delalloc(inode,
                                                      &BTRFS_I(inode)->io_tree,
                                                      start, end, NULL, 1, 1,
-                                                     1, 1, 1, 1);
+                                                     1, 1, 1, 1, 0);
                         *nr_written = *nr_written +
                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
                         *page_started = 1;
@@ -747,9 +748,9 @@ static noinline int cow_file_range(struct inode *inode,
                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 
                 while (1) {
-                        spin_lock(&em_tree->lock);
+                        write_lock(&em_tree->lock);
                         ret = add_extent_mapping(em_tree, em);
-                        spin_unlock(&em_tree->lock);
+                        write_unlock(&em_tree->lock);
                         if (ret != -EEXIST) {
                                 free_extent_map(em);
                                 break;
@@ -776,11 +777,14 @@ static noinline int cow_file_range(struct inode *inode,
                 /* we're not doing compressed IO, don't unlock the first
                  * page (which the caller expects to stay locked), don't
                  * clear any dirty bits and don't set any writeback bits
+                 *
+                 * Do set the Private2 bit so we know this page was properly
+                 * setup for writepage
                  */
                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
                                              start, start + ram_size - 1,
                                              locked_page, unlock, 1,
-                                             1, 0, 0, 0);
+                                             1, 0, 0, 0, 1);
                 disk_num_bytes -= cur_alloc_size;
                 num_bytes -= cur_alloc_size;
                 alloc_hint = ins.objectid + ins.offset;
@@ -853,7 +857,7 @@ static int cow_file_range_async(struct inode *inode, struct page *locked_page,
         int limit = 10 * 1024 * 1042;
 
         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED |
-                         EXTENT_DELALLOC, 1, 0, GFP_NOFS);
+                         EXTENT_DELALLOC, 1, 0, NULL, GFP_NOFS);
         while (start < end) {
                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
                 async_cow->inode = inode;
@@ -1080,9 +1084,9 @@ out_check:
                         em->bdev = root->fs_info->fs_devices->latest_bdev;
                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
                         while (1) {
-                                spin_lock(&em_tree->lock);
+                                write_lock(&em_tree->lock);
                                 ret = add_extent_mapping(em_tree, em);
-                                spin_unlock(&em_tree->lock);
+                                write_unlock(&em_tree->lock);
                                 if (ret != -EEXIST) {
                                         free_extent_map(em);
                                         break;
@@ -1101,7 +1105,7 @@ out_check:
 
                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
                                         cur_offset, cur_offset + num_bytes - 1,
-                                        locked_page, 1, 1, 1, 0, 0, 0);
+                                        locked_page, 1, 1, 1, 0, 0, 0, 1);
                 cur_offset = extent_end;
                 if (cur_offset > end)
                         break;
@@ -1374,10 +1378,8 @@ again:
         lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
 
         /* already ordered? We're done */
-        if (test_range_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
-                             EXTENT_ORDERED, 0)) {
+        if (PagePrivate2(page))
                 goto out;
-        }
 
         ordered = btrfs_lookup_ordered_extent(inode, page_start);
         if (ordered) {
@@ -1413,11 +1415,9 @@ static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
         struct inode *inode = page->mapping->host;
         struct btrfs_writepage_fixup *fixup;
         struct btrfs_root *root = BTRFS_I(inode)->root;
-        int ret;
 
-        ret = test_range_bit(&BTRFS_I(inode)->io_tree, start, end,
-                             EXTENT_ORDERED, 0);
-        if (ret)
+        /* this page is properly in the ordered list */
+        if (TestClearPagePrivate2(page))
                 return 0;
 
         if (PageChecked(page))
@@ -1455,9 +1455,19 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
         BUG_ON(!path);
 
         path->leave_spinning = 1;
+
+        /*
+         * we may be replacing one extent in the tree with another.
+         * The new extent is pinned in the extent map, and we don't want
+         * to drop it from the cache until it is completely in the btree.
+         *
+         * So, tell btrfs_drop_extents to leave this extent in the cache.
+         * the caller is expected to unpin it and allow it to be merged
+         * with the others.
+         */
         ret = btrfs_drop_extents(trans, root, inode, file_pos,
                                  file_pos + num_bytes, locked_end,
-                                 file_pos, &hint);
+                                 file_pos, &hint, 0);
         BUG_ON(ret);
 
         ins.objectid = inode->i_ino;
@@ -1485,7 +1495,6 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
         btrfs_mark_buffer_dirty(leaf);
 
         inode_add_bytes(inode, num_bytes);
-        btrfs_drop_extent_cache(inode, file_pos, file_pos + num_bytes - 1, 0);
 
         ins.objectid = disk_bytenr;
         ins.offset = disk_num_bytes;
@@ -1596,6 +1605,9 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
                                                 ordered_extent->len,
                                                 compressed, 0, 0,
                                                 BTRFS_FILE_EXTENT_REG);
+                unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
+                                   ordered_extent->file_offset,
+                                   ordered_extent->len);
                 BUG_ON(ret);
         }
         unlock_extent(io_tree, ordered_extent->file_offset,
@@ -1623,6 +1635,7 @@ nocow:
 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
                                 struct extent_state *state, int uptodate)
 {
+        ClearPagePrivate2(page);
         return btrfs_finish_ordered_io(page->mapping->host, start, end);
 }
 
@@ -1669,13 +1682,13 @@ static int btrfs_io_failed_hook(struct bio *failed_bio,
                 failrec->last_mirror = 0;
                 failrec->bio_flags = 0;
 
-                spin_lock(&em_tree->lock);
+                read_lock(&em_tree->lock);
                 em = lookup_extent_mapping(em_tree, start, failrec->len);
                 if (em->start > start || em->start + em->len < start) {
                         free_extent_map(em);
                         em = NULL;
                 }
-                spin_unlock(&em_tree->lock);
+                read_unlock(&em_tree->lock);
 
                 if (!em || IS_ERR(em)) {
                         kfree(failrec);
@@ -1794,7 +1807,7 @@ static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
                 return 0;
 
         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
-            test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1)) {
+            test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
                                   GFP_NOFS);
                 return 0;
@@ -2935,7 +2948,7 @@ int btrfs_cont_expand(struct inode *inode, loff_t size)
                                                  cur_offset,
                                                  cur_offset + hole_size,
                                                  block_end,
-                                                 cur_offset, &hint_byte);
+                                                 cur_offset, &hint_byte, 1);
                         if (err)
                                 break;
                         err = btrfs_insert_file_extent(trans, root,
@@ -4064,11 +4077,11 @@ struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
         int compressed;
 
 again:
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree, start, len);
         if (em)
                 em->bdev = root->fs_info->fs_devices->latest_bdev;
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
 
         if (em) {
                 if (em->start > start || em->start + em->len <= start)
@@ -4215,6 +4228,11 @@ again:
                                 map = kmap(page);
                                 read_extent_buffer(leaf, map + pg_offset, ptr,
                                                    copy_size);
+                                if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
+                                        memset(map + pg_offset + copy_size, 0,
+                                               PAGE_CACHE_SIZE - pg_offset -
+                                               copy_size);
+                                }
                                 kunmap(page);
                         }
                         flush_dcache_page(page);
@@ -4259,7 +4277,7 @@ insert:
         }
 
         err = 0;
-        spin_lock(&em_tree->lock);
+        write_lock(&em_tree->lock);
         ret = add_extent_mapping(em_tree, em);
         /* it is possible that someone inserted the extent into the tree
          * while we had the lock dropped.  It is also possible that
@@ -4299,7 +4317,7 @@ insert:
                         err = 0;
                 }
         }
-        spin_unlock(&em_tree->lock);
+        write_unlock(&em_tree->lock);
 out:
         if (path)
                 btrfs_free_path(path);
@@ -4398,13 +4416,21 @@ static void btrfs_invalidatepage(struct page *page, unsigned long offset)
         u64 page_start = page_offset(page);
         u64 page_end = page_start + PAGE_CACHE_SIZE - 1;
 
+
+        /*
+         * we have the page locked, so new writeback can't start,
+         * and the dirty bit won't be cleared while we are here.
+         *
+         * Wait for IO on this page so that we can safely clear
+         * the PagePrivate2 bit and do ordered accounting
+         */
         wait_on_page_writeback(page);
+
         tree = &BTRFS_I(page->mapping->host)->io_tree;
         if (offset) {
                 btrfs_releasepage(page, GFP_NOFS);
                 return;
         }
-
         lock_extent(tree, page_start, page_end, GFP_NOFS);
         ordered = btrfs_lookup_ordered_extent(page->mapping->host,
                                            page_offset(page));
@@ -4415,16 +4441,21 @@ static void btrfs_invalidatepage(struct page *page, unsigned long offset)
                  */
                 clear_extent_bit(tree, page_start, page_end,
                                  EXTENT_DIRTY | EXTENT_DELALLOC |
-                                 EXTENT_LOCKED, 1, 0, GFP_NOFS);
-                btrfs_finish_ordered_io(page->mapping->host,
-                                        page_start, page_end);
+                                 EXTENT_LOCKED, 1, 0, NULL, GFP_NOFS);
+                /*
+                 * whoever cleared the private bit is responsible
+                 * for the finish_ordered_io
+                 */
+                if (TestClearPagePrivate2(page)) {
+                        btrfs_finish_ordered_io(page->mapping->host,
+                                                page_start, page_end);
+                }
                 btrfs_put_ordered_extent(ordered);
                 lock_extent(tree, page_start, page_end, GFP_NOFS);
         }
         clear_extent_bit(tree, page_start, page_end,
-                 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC |
-                 EXTENT_ORDERED,
-                 1, 1, GFP_NOFS);
+                 EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC,
+                 1, 1, NULL, GFP_NOFS);
         __btrfs_releasepage(page, GFP_NOFS);
 
         ClearPageChecked(page);
@@ -4521,11 +4552,14 @@ again:
         }
         ClearPageChecked(page);
         set_page_dirty(page);
+        SetPageUptodate(page);
 
         BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 
 out_unlock:
+        if (!ret)
+                return VM_FAULT_LOCKED;
         unlock_page(page);
 out:
         return ret;
@@ -5058,6 +5092,8 @@ static int prealloc_file_range(struct btrfs_trans_handle *trans,
                                                   0, 0, 0,
                                                   BTRFS_FILE_EXTENT_PREALLOC);
                 BUG_ON(ret);
+                btrfs_drop_extent_cache(inode, cur_offset,
+                                        cur_offset + ins.offset -1, 0);
                 num_bytes -= ins.offset;
                 cur_offset += ins.offset;
                 alloc_hint = ins.objectid + ins.offset;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index bd88f25889f7..ef0188fb3cc4 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -596,9 +596,8 @@ again:
                 clear_page_dirty_for_io(page);
 
                 btrfs_set_extent_delalloc(inode, page_start, page_end);
-
-                unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
                 set_page_dirty(page);
+                unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
                 unlock_page(page);
                 page_cache_release(page);
                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
@@ -976,7 +975,7 @@ static long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 
         /* punch hole in destination first */
         btrfs_drop_extents(trans, root, inode, off, off + len,
-                           off + len, 0, &hint_byte);
+                           off + len, 0, &hint_byte, 1);
 
         /* clone data */
         key.objectid = src->i_ino;
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index d6f0806c682f..4a9c8c4cec25 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -159,8 +159,6 @@ static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
  *
  * len is the length of the extent
  *
- * This also sets the EXTENT_ORDERED bit on the range in the inode.
- *
  * The tree is given a single reference on the ordered extent that was
  * inserted.
  */
@@ -181,6 +179,7 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
         entry->start = start;
         entry->len = len;
         entry->disk_len = disk_len;
+        entry->bytes_left = len;
         entry->inode = inode;
         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
                 set_bit(type, &entry->flags);
@@ -195,9 +194,6 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
                            &entry->rb_node);
         BUG_ON(node);
 
-        set_extent_ordered(&BTRFS_I(inode)->io_tree, file_offset,
-                           entry_end(entry) - 1, GFP_NOFS);
-
         spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
         list_add_tail(&entry->root_extent_list,
                       &BTRFS_I(inode)->root->fs_info->ordered_extents);
@@ -241,13 +237,10 @@ int btrfs_dec_test_ordered_pending(struct inode *inode,
         struct btrfs_ordered_inode_tree *tree;
         struct rb_node *node;
         struct btrfs_ordered_extent *entry;
-        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
         int ret;
 
         tree = &BTRFS_I(inode)->ordered_tree;
         mutex_lock(&tree->mutex);
-        clear_extent_ordered(io_tree, file_offset, file_offset + io_size - 1,
-                             GFP_NOFS);
         node = tree_search(tree, file_offset);
         if (!node) {
                 ret = 1;
@@ -260,11 +253,16 @@ int btrfs_dec_test_ordered_pending(struct inode *inode,
                 goto out;
         }
 
-        ret = test_range_bit(io_tree, entry->file_offset,
-                             entry->file_offset + entry->len - 1,
-                             EXTENT_ORDERED, 0);
-        if (ret == 0)
+        if (io_size > entry->bytes_left) {
+                printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
+                       (unsigned long long)entry->bytes_left,
+                       (unsigned long long)io_size);
+        }
+        entry->bytes_left -= io_size;
+        if (entry->bytes_left == 0)
                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
+        else
+                ret = 1;
 out:
         mutex_unlock(&tree->mutex);
         return ret == 0;
@@ -476,6 +474,7 @@ int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
         u64 orig_end;
         u64 wait_end;
         struct btrfs_ordered_extent *ordered;
+        int found;
 
         if (start + len < start) {
                 orig_end = INT_LIMIT(loff_t);
@@ -502,6 +501,7 @@ again:
                                            orig_end >> PAGE_CACHE_SHIFT);
 
         end = orig_end;
+        found = 0;
         while (1) {
                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
                 if (!ordered)
@@ -514,6 +514,7 @@ again:
                         btrfs_put_ordered_extent(ordered);
                         break;
                 }
+                found++;
                 btrfs_start_ordered_extent(inode, ordered, 1);
                 end = ordered->file_offset;
                 btrfs_put_ordered_extent(ordered);
@@ -521,8 +522,8 @@ again:
                         break;
                 end--;
         }
-        if (test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
-                           EXTENT_ORDERED | EXTENT_DELALLOC, 0)) {
+        if (found || test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
+                           EXTENT_DELALLOC, 0, NULL)) {
                 schedule_timeout(1);
                 goto again;
         }
@@ -613,7 +614,7 @@ int btrfs_ordered_update_i_size(struct inode *inode,
          */
         if (test_range_bit(io_tree, disk_i_size,
                            ordered->file_offset + ordered->len - 1,
-                           EXTENT_DELALLOC, 0)) {
+                           EXTENT_DELALLOC, 0, NULL)) {
                 goto out;
         }
         /*
@@ -664,7 +665,7 @@ int btrfs_ordered_update_i_size(struct inode *inode,
          */
         if (i_size_test > entry_end(ordered) &&
             !test_range_bit(io_tree, entry_end(ordered), i_size_test - 1,
-                           EXTENT_DELALLOC, 0)) {
+                           EXTENT_DELALLOC, 0, NULL)) {
                 new_i_size = min_t(u64, i_size_test, i_size_read(inode));
         }
         BTRFS_I(inode)->disk_i_size = new_i_size;
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h
index 3d31c8827b01..993a7ea45c70 100644
--- a/fs/btrfs/ordered-data.h
+++ b/fs/btrfs/ordered-data.h
@@ -85,6 +85,9 @@ struct btrfs_ordered_extent {
         /* extent length on disk */
         u64 disk_len;
 
+        /* number of bytes that still need writing */
+        u64 bytes_left;
+
         /* flags (described above) */
         unsigned long flags;
 
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index c04f7f212602..3be16ccc7eea 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2180,7 +2180,7 @@ static int tree_block_processed(u64 bytenr, u32 blocksize,
                                 struct reloc_control *rc)
 {
         if (test_range_bit(&rc->processed_blocks, bytenr,
-                           bytenr + blocksize - 1, EXTENT_DIRTY, 1))
+                           bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
                 return 1;
         return 0;
 }
@@ -2646,9 +2646,9 @@ int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key)
         lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
         while (1) {
                 int ret;
-                spin_lock(&em_tree->lock);
+                write_lock(&em_tree->lock);
                 ret = add_extent_mapping(em_tree, em);
-                spin_unlock(&em_tree->lock);
+                write_unlock(&em_tree->lock);
                 if (ret != -EEXIST) {
                         free_extent_map(em);
                         break;
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index d91b0de7c502..8661a7381b39 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -534,7 +534,7 @@ static noinline int replay_one_extent(struct btrfs_trans_handle *trans,
         saved_nbytes = inode_get_bytes(inode);
         /* drop any overlapping extents */
         ret = btrfs_drop_extents(trans, root, inode,
-                         start, extent_end, extent_end, start, &alloc_hint);
+                         start, extent_end, extent_end, start, &alloc_hint, 1);
         BUG_ON(ret);
 
         if (found_type == BTRFS_FILE_EXTENT_REG ||
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5dbefd11b4af..d2358c06bbd9 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -276,7 +276,7 @@ loop_lock:
                  * is now congested.  Back off and let other work structs
                  * run instead
                  */
-                if (pending && bdi_write_congested(bdi) && batch_run > 32 &&
+                if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
                     fs_info->fs_devices->open_devices > 1) {
                         struct io_context *ioc;
 
@@ -1749,9 +1749,9 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
          * step two, delete the device extents and the
          * chunk tree entries
          */
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
 
         BUG_ON(em->start > chunk_offset ||
                em->start + em->len < chunk_offset);
@@ -1780,9 +1780,9 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset);
         BUG_ON(ret);
 
-        spin_lock(&em_tree->lock);
+        write_lock(&em_tree->lock);
         remove_extent_mapping(em_tree, em);
-        spin_unlock(&em_tree->lock);
+        write_unlock(&em_tree->lock);
 
         kfree(map);
         em->bdev = NULL;
@@ -2294,9 +2294,9 @@ again:
         em->block_len = em->len;
 
         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
-        spin_lock(&em_tree->lock);
+        write_lock(&em_tree->lock);
         ret = add_extent_mapping(em_tree, em);
-        spin_unlock(&em_tree->lock);
+        write_unlock(&em_tree->lock);
         BUG_ON(ret);
         free_extent_map(em);
 
@@ -2491,9 +2491,9 @@ int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
         int readonly = 0;
         int i;
 
-        spin_lock(&map_tree->map_tree.lock);
+        read_lock(&map_tree->map_tree.lock);
         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
-        spin_unlock(&map_tree->map_tree.lock);
+        read_unlock(&map_tree->map_tree.lock);
         if (!em)
                 return 1;
 
@@ -2518,11 +2518,11 @@ void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
         struct extent_map *em;
 
         while (1) {
-                spin_lock(&tree->map_tree.lock);
+                write_lock(&tree->map_tree.lock);
                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
                 if (em)
                         remove_extent_mapping(&tree->map_tree, em);
-                spin_unlock(&tree->map_tree.lock);
+                write_unlock(&tree->map_tree.lock);
                 if (!em)
                         break;
                 kfree(em->bdev);
@@ -2540,9 +2540,9 @@ int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
         struct extent_map_tree *em_tree = &map_tree->map_tree;
         int ret;
 
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree, logical, len);
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
         BUG_ON(!em);
 
         BUG_ON(em->start > logical || em->start + em->len < logical);
@@ -2604,9 +2604,9 @@ again:
                 atomic_set(&multi->error, 0);
         }
 
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree, logical, *length);
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
 
         if (!em && unplug_page)
                 return 0;
@@ -2763,9 +2763,9 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
         u64 stripe_nr;
         int i, j, nr = 0;
 
-        spin_lock(&em_tree->lock);
+        read_lock(&em_tree->lock);
         em = lookup_extent_mapping(em_tree, chunk_start, 1);
-        spin_unlock(&em_tree->lock);
+        read_unlock(&em_tree->lock);
 
         BUG_ON(!em || em->start != chunk_start);
         map = (struct map_lookup *)em->bdev;
@@ -3053,9 +3053,9 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
         logical = key->offset;
         length = btrfs_chunk_length(leaf, chunk);
 
-        spin_lock(&map_tree->map_tree.lock);
+        read_lock(&map_tree->map_tree.lock);
         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
-        spin_unlock(&map_tree->map_tree.lock);
+        read_unlock(&map_tree->map_tree.lock);
 
         /* already mapped? */
         if (em && em->start <= logical && em->start + em->len > logical) {
@@ -3114,9 +3114,9 @@ static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
                 map->stripes[i].dev->in_fs_metadata = 1;
         }
 
-        spin_lock(&map_tree->map_tree.lock);
+        write_lock(&map_tree->map_tree.lock);
         ret = add_extent_mapping(&map_tree->map_tree, em);
-        spin_unlock(&map_tree->map_tree.lock);
+        write_unlock(&map_tree->map_tree.lock);
         BUG_ON(ret);
         free_extent_map(em);