1 files changed, 500 insertions, 143 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3df0ffad976e..e01c0d0310ab 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -86,6 +86,10 @@ static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
 
 static void btrfs_truncate(struct inode *inode);
 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
+static noinline int cow_file_range(struct inode *inode,
+                                   struct page *locked_page,
+                                   u64 start, u64 end, int *page_started,
+                                   unsigned long *nr_written, int unlock);
 
 /*
  * a very lame attempt at stopping writes when the FS is 85% full.  There
@@ -262,35 +266,72 @@ static int cow_file_range_inline(struct btrfs_trans_handle *trans,
         return 0;
 }
 
+struct async_extent {
+        u64 start;
+        u64 ram_size;
+        u64 compressed_size;
+        struct page **pages;
+        unsigned long nr_pages;
+        struct list_head list;
+};
+
+struct async_cow {
+        struct inode *inode;
+        struct btrfs_root *root;
+        struct page *locked_page;
+        u64 start;
+        u64 end;
+        struct list_head extents;
+        struct btrfs_work work;
+};
+
+static noinline int add_async_extent(struct async_cow *cow,
+                                     u64 start, u64 ram_size,
+                                     u64 compressed_size,
+                                     struct page **pages,
+                                     unsigned long nr_pages)
+{
+        struct async_extent *async_extent;
+
+        async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
+        async_extent->start = start;
+        async_extent->ram_size = ram_size;
+        async_extent->compressed_size = compressed_size;
+        async_extent->pages = pages;
+        async_extent->nr_pages = nr_pages;
+        list_add_tail(&async_extent->list, &cow->extents);
+        return 0;
+}
+
 /*
- * when extent_io.c finds a delayed allocation range in the file,
- * the call backs end up in this code.  The basic idea is to
- * allocate extents on disk for the range, and create ordered data structs
- * in ram to track those extents.
+ * we create compressed extents in two phases.  The first
+ * phase compresses a range of pages that have already been
+ * locked (both pages and state bits are locked).
  *
- * locked_page is the page that writepage had locked already.  We use
- * it to make sure we don't do extra locks or unlocks.
+ * This is done inside an ordered work queue, and the compression
+ * is spread across many cpus.  The actual IO submission is step
+ * two, and the ordered work queue takes care of making sure that
+ * happens in the same order things were put onto the queue by
+ * writepages and friends.
  *
- * *page_started is set to one if we unlock locked_page and do everything
- * required to start IO on it.  It may be clean and already done with
- * IO when we return.
+ * If this code finds it can't get good compression, it puts an
+ * entry onto the work queue to write the uncompressed bytes.  This
+ * makes sure that both compressed inodes and uncompressed inodes
+ * are written in the same order that pdflush sent them down.
  */
-static int cow_file_range(struct inode *inode, struct page *locked_page,
-                          u64 start, u64 end, int *page_started)
+static noinline int compress_file_range(struct inode *inode,
+                                        struct page *locked_page,
+                                        u64 start, u64 end,
+                                        struct async_cow *async_cow,
+                                        int *num_added)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
-        u64 alloc_hint = 0;
         u64 num_bytes;
-        unsigned long ram_size;
         u64 orig_start;
         u64 disk_num_bytes;
-        u64 cur_alloc_size;
         u64 blocksize = root->sectorsize;
         u64 actual_end;
-        struct btrfs_key ins;
-        struct extent_map *em;
-        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
         int ret = 0;
         struct page **pages = NULL;
         unsigned long nr_pages;
@@ -298,22 +339,12 @@ static int cow_file_range(struct inode *inode, struct page *locked_page,
         unsigned long total_compressed = 0;
         unsigned long total_in = 0;
         unsigned long max_compressed = 128 * 1024;
-        unsigned long max_uncompressed = 256 * 1024;
+        unsigned long max_uncompressed = 128 * 1024;
         int i;
-        int ordered_type;
         int will_compress;
 
-        trans = btrfs_join_transaction(root, 1);
-        BUG_ON(!trans);
-        btrfs_set_trans_block_group(trans, inode);
         orig_start = start;
 
-        /*
-         * compression made this loop a bit ugly, but the basic idea is to
-         * compress some pages but keep the total size of the compressed
-         * extent relatively small.  If compression is off, this goto target
-         * is never used.
-         */
 again:
         will_compress = 0;
         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
@@ -324,7 +355,13 @@ again:
 
         /* we want to make sure that amount of ram required to uncompress
          * an extent is reasonable, so we limit the total size in ram
-         * of a compressed extent to 256k
+         * of a compressed extent to 128k.  This is a crucial number
+         * because it also controls how easily we can spread reads across
+         * cpus for decompression.
+         *
+         * We also want to make sure the amount of IO required to do
+         * a random read is reasonably small, so we limit the size of
+         * a compressed extent to 128k.
          */
         total_compressed = min(total_compressed, max_uncompressed);
         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
@@ -333,18 +370,16 @@ again:
         total_in = 0;
         ret = 0;
 
-        /* we do compression for mount -o compress and when the
-         * inode has not been flagged as nocompress
+        /*
+         * we do compression for mount -o compress and when the
+         * inode has not been flagged as nocompress.  This flag can
+         * change at any time if we discover bad compression ratios.
          */
         if (!btrfs_test_flag(inode, NOCOMPRESS) &&
             btrfs_test_opt(root, COMPRESS)) {
                 WARN_ON(pages);
                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
 
-                /* we want to make sure the amount of IO required to satisfy
-                 * a random read is reasonably small, so we limit the size
-                 * of a compressed extent to 128k
-                 */
                 ret = btrfs_zlib_compress_pages(inode->i_mapping, start,
                                                 total_compressed, pages,
                                                 nr_pages, &nr_pages_ret,
@@ -371,26 +406,34 @@ again:
                 }
         }
         if (start == 0) {
+                trans = btrfs_join_transaction(root, 1);
+                BUG_ON(!trans);
+                btrfs_set_trans_block_group(trans, inode);
+
                 /* lets try to make an inline extent */
-                if (ret || total_in < (end - start + 1)) {
+                if (ret || total_in < (actual_end - start)) {
                         /* we didn't compress the entire range, try
-                         * to make an uncompressed inline extent.  This
-                         * is almost sure to fail, but maybe inline sizes
-                         * will get bigger later
+                         * to make an uncompressed inline extent.
                          */
                         ret = cow_file_range_inline(trans, root, inode,
                                                     start, end, 0, NULL);
                 } else {
+                        /* try making a compressed inline extent */
                         ret = cow_file_range_inline(trans, root, inode,
                                                     start, end,
                                                     total_compressed, pages);
                 }
+                btrfs_end_transaction(trans, root);
                 if (ret == 0) {
+                        /*
+                         * inline extent creation worked, we don't need
+                         * to create any more async work items.  Unlock
+                         * and free up our temp pages.
+                         */
                         extent_clear_unlock_delalloc(inode,
                                                      &BTRFS_I(inode)->io_tree,
-                                                     start, end, NULL,
-                                                     1, 1, 1);
-                        *page_started = 1;
+                                                     start, end, NULL, 1, 0,
+                                                     0, 1, 1, 1);
                         ret = 0;
                         goto free_pages_out;
                 }
@@ -435,53 +478,280 @@ again:
                 /* flag the file so we don't compress in the future */
                 btrfs_set_flag(inode, NOCOMPRESS);
         }
+        if (will_compress) {
+                *num_added += 1;
 
-        BUG_ON(disk_num_bytes >
-               btrfs_super_total_bytes(&root->fs_info->super_copy));
+                /* the async work queues will take care of doing actual
+                 * allocation on disk for these compressed pages,
+                 * and will submit them to the elevator.
+                 */
+                add_async_extent(async_cow, start, num_bytes,
+                                 total_compressed, pages, nr_pages_ret);
 
-        btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
+                if (start + num_bytes < end) {
+                        start += num_bytes;
+                        pages = NULL;
+                        cond_resched();
+                        goto again;
+                }
+        } else {
+                /*
+                 * No compression, but we still need to write the pages in
+                 * the file we've been given so far.  redirty the locked
+                 * page if it corresponds to our extent and set things up
+                 * for the async work queue to run cow_file_range to do
+                 * the normal delalloc dance
+                 */
+                if (page_offset(locked_page) >= start &&
+                    page_offset(locked_page) <= end) {
+                        __set_page_dirty_nobuffers(locked_page);
+                        /* unlocked later on in the async handlers */
+                }
+                add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0);
+                *num_added += 1;
+        }
 
-        while(disk_num_bytes > 0) {
-                unsigned long min_bytes;
+out:
+        return 0;
+
+free_pages_out:
+        for (i = 0; i < nr_pages_ret; i++) {
+                WARN_ON(pages[i]->mapping);
+                page_cache_release(pages[i]);
+        }
+        if (pages)
+                kfree(pages);
+
+        goto out;
+}
+
+/*
+ * phase two of compressed writeback.  This is the ordered portion
+ * of the code, which only gets called in the order the work was
+ * queued.  We walk all the async extents created by compress_file_range
+ * and send them down to the disk.
+ */
+static noinline int submit_compressed_extents(struct inode *inode,
+                                              struct async_cow *async_cow)
+{
+        struct async_extent *async_extent;
+        u64 alloc_hint = 0;
+        struct btrfs_trans_handle *trans;
+        struct btrfs_key ins;
+        struct extent_map *em;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+        struct extent_io_tree *io_tree;
+        int ret;
+
+        if (list_empty(&async_cow->extents))
+                return 0;
+
+        trans = btrfs_join_transaction(root, 1);
+
+        while(!list_empty(&async_cow->extents)) {
+                async_extent = list_entry(async_cow->extents.next,
+                                          struct async_extent, list);
+                list_del(&async_extent->list);
 
+                io_tree = &BTRFS_I(inode)->io_tree;
+
+                /* did the compression code fall back to uncompressed IO? */
+                if (!async_extent->pages) {
+                        int page_started = 0;
+                        unsigned long nr_written = 0;
+
+                        lock_extent(io_tree, async_extent->start,
+                                    async_extent->start + async_extent->ram_size - 1,
+                                    GFP_NOFS);
+
+                        /* allocate blocks */
+                        cow_file_range(inode, async_cow->locked_page,
+                                       async_extent->start,
+                                       async_extent->start +
+                                       async_extent->ram_size - 1,
+                                       &page_started, &nr_written, 0);
+
+                        /*
+                         * if page_started, cow_file_range inserted an
+                         * inline extent and took care of all the unlocking
+                         * and IO for us.  Otherwise, we need to submit
+                         * all those pages down to the drive.
+                         */
+                        if (!page_started)
+                                extent_write_locked_range(io_tree,
+                                                  inode, async_extent->start,
+                                                  async_extent->start +
+                                                  async_extent->ram_size - 1,
+                                                  btrfs_get_extent,
+                                                  WB_SYNC_ALL);
+                        kfree(async_extent);
+                        cond_resched();
+                        continue;
+                }
+
+                lock_extent(io_tree, async_extent->start,
+                            async_extent->start + async_extent->ram_size - 1,
+                            GFP_NOFS);
                 /*
-                 * the max size of a compressed extent is pretty small,
-                 * make the code a little less complex by forcing
-                 * the allocator to find a whole compressed extent at once
+                 * here we're doing allocation and writeback of the
+                 * compressed pages
                  */
-                if (will_compress)
-                        min_bytes = disk_num_bytes;
-                else
-                        min_bytes = root->sectorsize;
+                btrfs_drop_extent_cache(inode, async_extent->start,
+                                        async_extent->start +
+                                        async_extent->ram_size - 1, 0);
+
+                ret = btrfs_reserve_extent(trans, root,
+                                           async_extent->compressed_size,
+                                           async_extent->compressed_size,
+                                           0, alloc_hint,
+                                           (u64)-1, &ins, 1);
+                BUG_ON(ret);
+                em = alloc_extent_map(GFP_NOFS);
+                em->start = async_extent->start;
+                em->len = async_extent->ram_size;
+
+                em->block_start = ins.objectid;
+                em->block_len = ins.offset;
+                em->bdev = root->fs_info->fs_devices->latest_bdev;
+                set_bit(EXTENT_FLAG_PINNED, &em->flags);
+                set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
+
+                while(1) {
+                        spin_lock(&em_tree->lock);
+                        ret = add_extent_mapping(em_tree, em);
+                        spin_unlock(&em_tree->lock);
+                        if (ret != -EEXIST) {
+                                free_extent_map(em);
+                                break;
+                        }
+                        btrfs_drop_extent_cache(inode, async_extent->start,
+                                                async_extent->start +
+                                                async_extent->ram_size - 1, 0);
+                }
+
+                ret = btrfs_add_ordered_extent(inode, async_extent->start,
+                                               ins.objectid,
+                                               async_extent->ram_size,
+                                               ins.offset,
+                                               BTRFS_ORDERED_COMPRESSED);
+                BUG_ON(ret);
+
+                btrfs_end_transaction(trans, root);
+
+                /*
+                 * clear dirty, set writeback and unlock the pages.
+                 */
+                extent_clear_unlock_delalloc(inode,
+                                             &BTRFS_I(inode)->io_tree,
+                                             async_extent->start,
+                                             async_extent->start +
+                                             async_extent->ram_size - 1,
+                                             NULL, 1, 1, 0, 1, 1, 0);
+
+                ret = btrfs_submit_compressed_write(inode,
+                                         async_extent->start,
+                                         async_extent->ram_size,
+                                         ins.objectid,
+                                         ins.offset, async_extent->pages,
+                                         async_extent->nr_pages);
+
+                BUG_ON(ret);
+                trans = btrfs_join_transaction(root, 1);
+                alloc_hint = ins.objectid + ins.offset;
+                kfree(async_extent);
+                cond_resched();
+        }
+
+        btrfs_end_transaction(trans, root);
+        return 0;
+}
+
+/*
+ * when extent_io.c finds a delayed allocation range in the file,
+ * the call backs end up in this code.  The basic idea is to
+ * allocate extents on disk for the range, and create ordered data structs
+ * in ram to track those extents.
+ *
+ * locked_page is the page that writepage had locked already.  We use
+ * it to make sure we don't do extra locks or unlocks.
+ *
+ * *page_started is set to one if we unlock locked_page and do everything
+ * required to start IO on it.  It may be clean and already done with
+ * IO when we return.
+ */
+static noinline int cow_file_range(struct inode *inode,
+                                   struct page *locked_page,
+                                   u64 start, u64 end, int *page_started,
+                                   unsigned long *nr_written,
+                                   int unlock)
+{
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct btrfs_trans_handle *trans;
+        u64 alloc_hint = 0;
+        u64 num_bytes;
+        unsigned long ram_size;
+        u64 disk_num_bytes;
+        u64 cur_alloc_size;
+        u64 blocksize = root->sectorsize;
+        u64 actual_end;
+        struct btrfs_key ins;
+        struct extent_map *em;
+        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+        int ret = 0;
+
+        trans = btrfs_join_transaction(root, 1);
+        BUG_ON(!trans);
+        btrfs_set_trans_block_group(trans, inode);
 
+        actual_end = min_t(u64, i_size_read(inode), end + 1);
+
+        num_bytes = (end - start + blocksize) & ~(blocksize - 1);
+        num_bytes = max(blocksize,  num_bytes);
+        disk_num_bytes = num_bytes;
+        ret = 0;
+
+        if (start == 0) {
+                /* lets try to make an inline extent */
+                ret = cow_file_range_inline(trans, root, inode,
+                                            start, end, 0, NULL);
+                if (ret == 0) {
+                        extent_clear_unlock_delalloc(inode,
+                                                     &BTRFS_I(inode)->io_tree,
+                                                     start, end, NULL, 1, 1,
+                                                     1, 1, 1, 1);
+                        *nr_written = *nr_written +
+                             (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
+                        *page_started = 1;
+                        ret = 0;
+                        goto out;
+                }
+        }
+
+        BUG_ON(disk_num_bytes >
+               btrfs_super_total_bytes(&root->fs_info->super_copy));
+
+        btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
+
+        while(disk_num_bytes > 0) {
                 cur_alloc_size = min(disk_num_bytes, root->fs_info->max_extent);
                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
-                                           min_bytes, 0, alloc_hint,
+                                           root->sectorsize, 0, alloc_hint,
                                            (u64)-1, &ins, 1);
                 if (ret) {
-                        WARN_ON(1);
-                        goto free_pages_out_fail;
+                        BUG();
                 }
                 em = alloc_extent_map(GFP_NOFS);
                 em->start = start;
 
-                if (will_compress) {
-                        ram_size = num_bytes;
-                        em->len = num_bytes;
-                } else {
-                        /* ramsize == disk size */
-                        ram_size = ins.offset;
-                        em->len = ins.offset;
-                }
+                ram_size = ins.offset;
+                em->len = ins.offset;
 
                 em->block_start = ins.objectid;
                 em->block_len = ins.offset;
                 em->bdev = root->fs_info->fs_devices->latest_bdev;
                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
 
-                if (will_compress)
-                        set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
-
                 while(1) {
                         spin_lock(&em_tree->lock);
                         ret = add_extent_mapping(em_tree, em);
@@ -495,10 +765,8 @@ again:
                 }
 
                 cur_alloc_size = ins.offset;
-                ordered_type = will_compress ? BTRFS_ORDERED_COMPRESSED : 0;
                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
-                                               ram_size, cur_alloc_size,
-                                               ordered_type);
+                                               ram_size, cur_alloc_size, 0);
                 BUG_ON(ret);
 
                 if (disk_num_bytes < cur_alloc_size) {
@@ -506,82 +774,145 @@ again:
                                cur_alloc_size);
                         break;
                 }
-
-                if (will_compress) {
-                        /*
-                         * we're doing compression, we and we need to
-                         * submit the compressed extents down to the device.
-                         *
-                         * We lock down all the file pages, clearing their
-                         * dirty bits and setting them writeback.  Everyone
-                         * that wants to modify the page will wait on the
-                         * ordered extent above.
-                         *
-                         * The writeback bits on the file pages are
-                         * cleared when the compressed pages are on disk
-                         */
-                        btrfs_end_transaction(trans, root);
-
-                        if (start <= page_offset(locked_page) &&
-                            page_offset(locked_page) < start + ram_size) {
-                                *page_started = 1;
-                        }
-
-                        extent_clear_unlock_delalloc(inode,
-                                                     &BTRFS_I(inode)->io_tree,
-                                                     start,
-                                                     start + ram_size - 1,
-                                                     NULL, 1, 1, 0);
-
-                        ret = btrfs_submit_compressed_write(inode, start,
-                                                 ram_size, ins.objectid,
-                                                 cur_alloc_size, pages,
-                                                 nr_pages_ret);
-
-                        BUG_ON(ret);
-                        trans = btrfs_join_transaction(root, 1);
-                        if (start + ram_size < end) {
-                                start += ram_size;
-                                alloc_hint = ins.objectid + ins.offset;
-                                /* pages will be freed at end_bio time */
-                                pages = NULL;
-                                goto again;
-                        } else {
-                                /* we've written everything, time to go */
-                                break;
-                        }
-                }
                 /* 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
                  */
                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
                                              start, start + ram_size - 1,
-                                             locked_page, 0, 0, 0);
+                                             locked_page, unlock, 1,
+                                             1, 0, 0, 0);
                 disk_num_bytes -= cur_alloc_size;
                 num_bytes -= cur_alloc_size;
                 alloc_hint = ins.objectid + ins.offset;
                 start += cur_alloc_size;
         }
-
-        ret = 0;
 out:
+        ret = 0;
         btrfs_end_transaction(trans, root);
 
         return ret;
+}
 
-free_pages_out_fail:
-        extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
-                                     start, end, locked_page, 0, 0, 0);
-free_pages_out:
-        for (i = 0; i < nr_pages_ret; i++) {
-                WARN_ON(pages[i]->mapping);
-                page_cache_release(pages[i]);
+/*
+ * work queue call back to started compression on a file and pages
+ */
+static noinline void async_cow_start(struct btrfs_work *work)
+{
+        struct async_cow *async_cow;
+        int num_added = 0;
+        async_cow = container_of(work, struct async_cow, work);
+
+        compress_file_range(async_cow->inode, async_cow->locked_page,
+                            async_cow->start, async_cow->end, async_cow,
+                            &num_added);
+        if (num_added == 0)
+                async_cow->inode = NULL;
+}
+
+/*
+ * work queue call back to submit previously compressed pages
+ */
+static noinline void async_cow_submit(struct btrfs_work *work)
+{
+        struct async_cow *async_cow;
+        struct btrfs_root *root;
+        unsigned long nr_pages;
+
+        async_cow = container_of(work, struct async_cow, work);
+
+        root = async_cow->root;
+        nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
+                PAGE_CACHE_SHIFT;
+
+        atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
+
+        if (atomic_read(&root->fs_info->async_delalloc_pages) <
+            5 * 1042 * 1024 &&
+            waitqueue_active(&root->fs_info->async_submit_wait))
+                wake_up(&root->fs_info->async_submit_wait);
+
+        if (async_cow->inode) {
+                submit_compressed_extents(async_cow->inode, async_cow);
         }
-        if (pages)
-                kfree(pages);
+}
 
-        goto out;
+static noinline void async_cow_free(struct btrfs_work *work)
+{
+        struct async_cow *async_cow;
+        async_cow = container_of(work, struct async_cow, work);
+        kfree(async_cow);
+}
+
+static int cow_file_range_async(struct inode *inode, struct page *locked_page,
+                                u64 start, u64 end, int *page_started,
+                                unsigned long *nr_written)
+{
+        struct async_cow *async_cow;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        unsigned long nr_pages;
+        u64 cur_end;
+        int limit = 10 * 1024 * 1042;
+
+        if (!btrfs_test_opt(root, COMPRESS)) {
+                return cow_file_range(inode, locked_page, start, end,
+                                      page_started, nr_written, 1);
+        }
+
+        clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED |
+                         EXTENT_DELALLOC, 1, 0, GFP_NOFS);
+        while(start < end) {
+                async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
+                async_cow->inode = inode;
+                async_cow->root = root;
+                async_cow->locked_page = locked_page;
+                async_cow->start = start;
+
+                if (btrfs_test_flag(inode, NOCOMPRESS))
+                        cur_end = end;
+                else
+                        cur_end = min(end, start + 512 * 1024 - 1);
+
+                async_cow->end = cur_end;
+                INIT_LIST_HEAD(&async_cow->extents);
+
+                async_cow->work.func = async_cow_start;
+                async_cow->work.ordered_func = async_cow_submit;
+                async_cow->work.ordered_free = async_cow_free;
+                async_cow->work.flags = 0;
+
+                while(atomic_read(&root->fs_info->async_submit_draining) &&
+                      atomic_read(&root->fs_info->async_delalloc_pages)) {
+                        wait_event(root->fs_info->async_submit_wait,
+                             (atomic_read(&root->fs_info->async_delalloc_pages)
+                              == 0));
+                }
+
+                nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
+                        PAGE_CACHE_SHIFT;
+                atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
+
+                btrfs_queue_worker(&root->fs_info->delalloc_workers,
+                                   &async_cow->work);
+
+                if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
+                        wait_event(root->fs_info->async_submit_wait,
+                           (atomic_read(&root->fs_info->async_delalloc_pages) <
+                            limit));
+                }
+
+                while(atomic_read(&root->fs_info->async_submit_draining) &&
+                      atomic_read(&root->fs_info->async_delalloc_pages)) {
+                        wait_event(root->fs_info->async_submit_wait,
+                          (atomic_read(&root->fs_info->async_delalloc_pages) ==
+                           0));
+                }
+
+                *nr_written += nr_pages;
+                start = cur_end + 1;
+        }
+        *page_started = 1;
+        return 0;
 }
 
 /*
@@ -592,7 +923,8 @@ free_pages_out:
  * blocks on disk
  */
 static int run_delalloc_nocow(struct inode *inode, struct page *locked_page,
-                              u64 start, u64 end, int *page_started, int force)
+                              u64 start, u64 end, int *page_started, int force,
+                              unsigned long *nr_written)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
@@ -711,7 +1043,8 @@ out_check:
                 btrfs_release_path(root, path);
                 if (cow_start != (u64)-1) {
                         ret = cow_file_range(inode, locked_page, cow_start,
-                                        found_key.offset - 1, page_started);
+                                        found_key.offset - 1, page_started,
+                                        nr_written, 1);
                         BUG_ON(ret);
                         cow_start = (u64)-1;
                 }
@@ -748,9 +1081,10 @@ out_check:
                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
                                                num_bytes, num_bytes, type);
                 BUG_ON(ret);
+
                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
                                         cur_offset, cur_offset + num_bytes - 1,
-                                        locked_page, 0, 0, 0);
+                                        locked_page, 1, 1, 1, 0, 0, 0);
                 cur_offset = extent_end;
                 if (cur_offset > end)
                         break;
@@ -761,7 +1095,7 @@ out_check:
                 cow_start = cur_offset;
         if (cow_start != (u64)-1) {
                 ret = cow_file_range(inode, locked_page, cow_start, end,
-                                     page_started);
+                                     page_started, nr_written, 1);
                 BUG_ON(ret);
         }
 
@@ -775,7 +1109,8 @@ out_check:
  * extent_io.c call back to do delayed allocation processing
  */
 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
-                              u64 start, u64 end, int *page_started)
+                              u64 start, u64 end, int *page_started,
+                              unsigned long *nr_written)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         int ret;
@@ -783,13 +1118,13 @@ static int run_delalloc_range(struct inode *inode, struct page *locked_page,
         if (btrfs_test_opt(root, NODATACOW) ||
             btrfs_test_flag(inode, NODATACOW))
                 ret = run_delalloc_nocow(inode, locked_page, start, end,
-                                         page_started, 0);
+                                         page_started, 0, nr_written);
         else if (btrfs_test_flag(inode, PREALLOC))
                 ret = run_delalloc_nocow(inode, locked_page, start, end,
-                                         page_started, 1);
+                                         page_started, 1, nr_written);
         else
-                ret = cow_file_range(inode, locked_page, start, end,
-                                     page_started);
+                ret = cow_file_range_async(inode, locked_page, start, end,
+                                     page_started, nr_written);
 
         return ret;
 }
@@ -861,6 +1196,9 @@ int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
         u64 map_length;
         int ret;
 
+        if (bio_flags & EXTENT_BIO_COMPRESSED)
+                return 0;
+
         length = bio->bi_size;
         map_tree = &root->fs_info->mapping_tree;
         map_length = length;
@@ -925,12 +1263,12 @@ int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
                 btrfs_test_flag(inode, NODATASUM);
 
         if (!(rw & (1 << BIO_RW))) {
-                if (!skip_sum)
-                        btrfs_lookup_bio_sums(root, inode, bio);
 
                 if (bio_flags & EXTENT_BIO_COMPRESSED)
                         return btrfs_submit_compressed_read(inode, bio,
                                                     mirror_num, bio_flags);
+                else if (!skip_sum)
+                        btrfs_lookup_bio_sums(root, inode, bio);
                 goto mapit;
         } else if (!skip_sum) {
                 /* we're doing a write, do the async checksumming */
@@ -966,6 +1304,9 @@ static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
 
 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end)
 {
+        if ((end & (PAGE_CACHE_SIZE - 1)) == 0) {
+                WARN_ON(1);
+        }
         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
                                    GFP_NOFS);
 }
@@ -2105,6 +2446,7 @@ noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
         int pending_del_nr = 0;
         int pending_del_slot = 0;
         int extent_type = -1;
+        int encoding;
         u64 mask = root->sectorsize - 1;
 
         if (root->ref_cows)
@@ -2144,6 +2486,7 @@ search_again:
                 leaf = path->nodes[0];
                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
                 found_type = btrfs_key_type(&found_key);
+                encoding = 0;
 
                 if (found_key.objectid != inode->i_ino)
                         break;
@@ -2156,6 +2499,10 @@ search_again:
                         fi = btrfs_item_ptr(leaf, path->slots[0],
                                             struct btrfs_file_extent_item);
                         extent_type = btrfs_file_extent_type(leaf, fi);
+                        encoding = btrfs_file_extent_compression(leaf, fi);
+                        encoding |= btrfs_file_extent_encryption(leaf, fi);
+                        encoding |= btrfs_file_extent_other_encoding(leaf, fi);
+
                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
                                 item_end +=
                                     btrfs_file_extent_num_bytes(leaf, fi);
@@ -2200,7 +2547,7 @@ search_again:
                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
                         u64 num_dec;
                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
-                        if (!del_item) {
+                        if (!del_item && !encoding) {
                                 u64 orig_num_bytes =
                                         btrfs_file_extent_num_bytes(leaf, fi);
                                 extent_num_bytes = new_size -
@@ -2436,7 +2783,14 @@ int btrfs_cont_expand(struct inode *inode, loff_t size)
                 last_byte = min(extent_map_end(em), block_end);
                 last_byte = (last_byte + mask) & ~mask;
                 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+                        u64 hint_byte = 0;
                         hole_size = last_byte - cur_offset;
+                        err = btrfs_drop_extents(trans, root, inode,
+                                                 cur_offset,
+                                                 cur_offset + hole_size,
+                                                 cur_offset, &hint_byte);
+                        if (err)
+                                break;
                         err = btrfs_insert_file_extent(trans, root,
                                         inode->i_ino, cur_offset, 0,
                                         0, hole_size, 0, hole_size,
@@ -3785,6 +4139,7 @@ int btrfs_writepages(struct address_space *mapping,
                      struct writeback_control *wbc)
 {
         struct extent_io_tree *tree;
+
         tree = &BTRFS_I(mapping->host)->io_tree;
         return extent_writepages(tree, mapping, btrfs_get_extent, wbc);
 }
@@ -4285,9 +4640,11 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root)
          * ordered extents get created before we return
          */
         atomic_inc(&root->fs_info->async_submit_draining);
-        while(atomic_read(&root->fs_info->nr_async_submits)) {
+        while(atomic_read(&root->fs_info->nr_async_submits) ||
+              atomic_read(&root->fs_info->async_delalloc_pages)) {
                 wait_event(root->fs_info->async_submit_wait,
-                   (atomic_read(&root->fs_info->nr_async_submits) == 0));
+                   (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
+                    atomic_read(&root->fs_info->async_delalloc_pages) == 0));
         }
         atomic_dec(&root->fs_info->async_submit_draining);
         return 0;