]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - fs/btrfs/inode.c
Btrfs: Give each subvol and snapshot their own anonymous devid
[linux-2.6-omap-h63xx.git] / fs / btrfs / inode.c
index 6739424c0fe683b40fa076a9c438c4d8a0bed63a..7ef79ce86e2514d5b4c496c9cff1628911edfa07 100644 (file)
@@ -37,6 +37,7 @@
 #include <linux/version.h>
 #include <linux/xattr.h>
 #include <linux/posix_acl.h>
+#include <linux/falloc.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
@@ -85,6 +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
@@ -179,7 +184,7 @@ static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
                int i = 0;
                while(compressed_size > 0) {
                        cpage = compressed_pages[i];
-                       cur_size = min(compressed_size,
+                       cur_size = min_t(unsigned long, compressed_size,
                                       PAGE_CACHE_SIZE);
 
                        kaddr = kmap(cpage);
@@ -238,6 +243,7 @@ static int cow_file_range_inline(struct btrfs_trans_handle *trans,
                data_len = compressed_size;
 
        if (start > 0 ||
+           actual_end >= PAGE_CACHE_SIZE ||
            data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
            (!compressed_size &&
            (actual_end & (root->sectorsize - 1)) == 0) ||
@@ -246,9 +252,8 @@ static int cow_file_range_inline(struct btrfs_trans_handle *trans,
                return 1;
        }
 
-       mutex_lock(&BTRFS_I(inode)->extent_mutex);
        ret = btrfs_drop_extents(trans, root, inode, start,
-                                aligned_end, aligned_end, &hint_byte);
+                                aligned_end, start, &hint_byte);
        BUG_ON(ret);
 
        if (isize > actual_end)
@@ -258,39 +263,75 @@ static int cow_file_range_inline(struct btrfs_trans_handle *trans,
                                   compressed_pages);
        BUG_ON(ret);
        btrfs_drop_extent_cache(inode, start, aligned_end, 0);
-       mutex_unlock(&BTRFS_I(inode)->extent_mutex);
+       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;
@@ -298,21 +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 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;
@@ -323,7 +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);
@@ -332,18 +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,
@@ -370,26 +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;
                }
@@ -423,6 +467,7 @@ again:
                 * free any pages it allocated and our page pointer array
                 */
                for (i = 0; i < nr_pages_ret; i++) {
+                       WARN_ON(pages[i]->mapping);
                        page_cache_release(pages[i]);
                }
                kfree(pages);
@@ -433,57 +478,282 @@ again:
                /* flag the file so we don't compress in the future */
                btrfs_set_flag(inode, NOCOMPRESS);
        }
+       if (will_compress) {
+               *num_added += 1;
+
+               /* 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);
+
+               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;
+       }
 
-       BUG_ON(disk_num_bytes >
-              btrfs_super_total_bytes(&root->fs_info->super_copy));
+out:
+       return 0;
 
-       mutex_lock(&BTRFS_I(inode)->extent_mutex);
-       btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
-       mutex_unlock(&BTRFS_I(inode)->extent_mutex);
+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);
 
-       while(disk_num_bytes > 0) {
-               unsigned long min_bytes;
+       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->orig_start = em->start;
+
+               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;
+               em->orig_start = em->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;
-
-               mutex_lock(&BTRFS_I(inode)->extent_mutex);
                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);
@@ -495,12 +765,10 @@ again:
                        btrfs_drop_extent_cache(inode, start,
                                                start + ram_size - 1, 0);
                }
-               mutex_unlock(&BTRFS_I(inode)->extent_mutex);
 
                cur_alloc_size = ins.offset;
                ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
-                                              ram_size, cur_alloc_size, 0,
-                                              will_compress);
+                                              ram_size, cur_alloc_size, 0);
                BUG_ON(ret);
 
                if (disk_num_bytes < cur_alloc_size) {
@@ -508,80 +776,145 @@ 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++)
-               page_cache_release(pages[i]);
-       if (pages)
-               kfree(pages);
+/*
+ * 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;
+}
 
-       goto out;
+/*
+ * 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);
+       }
+}
+
+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;
 }
 
 /*
@@ -592,124 +925,195 @@ 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)
+                             u64 start, u64 end, int *page_started, int force,
+                             unsigned long *nr_written)
 {
-       u64 extent_start;
-       u64 extent_end;
-       u64 bytenr;
-       u64 loops = 0;
-       u64 total_fs_bytes;
        struct btrfs_root *root = BTRFS_I(inode)->root;
-       struct btrfs_block_group_cache *block_group;
        struct btrfs_trans_handle *trans;
        struct extent_buffer *leaf;
-       int found_type;
        struct btrfs_path *path;
-       struct btrfs_file_extent_item *item;
-       int ret;
-       int err = 0;
+       struct btrfs_file_extent_item *fi;
        struct btrfs_key found_key;
+       u64 cow_start;
+       u64 cur_offset;
+       u64 extent_end;
+       u64 disk_bytenr;
+       u64 num_bytes;
+       int extent_type;
+       int ret;
+       int type;
+       int nocow;
+       int check_prev = 1;
 
-       total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
        path = btrfs_alloc_path();
        BUG_ON(!path);
        trans = btrfs_join_transaction(root, 1);
        BUG_ON(!trans);
-again:
-       ret = btrfs_lookup_file_extent(NULL, root, path,
-                                      inode->i_ino, start, 0);
-       if (ret < 0) {
-               err = ret;
-               goto out;
-       }
 
-       if (ret != 0) {
-               if (path->slots[0] == 0)
-                       goto not_found;
-               path->slots[0]--;
-       }
-
-       leaf = path->nodes[0];
-       item = btrfs_item_ptr(leaf, path->slots[0],
-                             struct btrfs_file_extent_item);
-
-       /* are we inside the extent that was found? */
-       btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
-       found_type = btrfs_key_type(&found_key);
-       if (found_key.objectid != inode->i_ino ||
-           found_type != BTRFS_EXTENT_DATA_KEY)
-               goto not_found;
+       cow_start = (u64)-1;
+       cur_offset = start;
+       while (1) {
+               ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
+                                              cur_offset, 0);
+               BUG_ON(ret < 0);
+               if (ret > 0 && path->slots[0] > 0 && check_prev) {
+                       leaf = path->nodes[0];
+                       btrfs_item_key_to_cpu(leaf, &found_key,
+                                             path->slots[0] - 1);
+                       if (found_key.objectid == inode->i_ino &&
+                           found_key.type == BTRFS_EXTENT_DATA_KEY)
+                               path->slots[0]--;
+               }
+               check_prev = 0;
+next_slot:
+               leaf = path->nodes[0];
+               if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+                       ret = btrfs_next_leaf(root, path);
+                       if (ret < 0)
+                               BUG_ON(1);
+                       if (ret > 0)
+                               break;
+                       leaf = path->nodes[0];
+               }
 
-       found_type = btrfs_file_extent_type(leaf, item);
-       extent_start = found_key.offset;
-       if (found_type == BTRFS_FILE_EXTENT_REG) {
-               u64 extent_num_bytes;
+               nocow = 0;
+               disk_bytenr = 0;
+               btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 
-               extent_num_bytes = btrfs_file_extent_num_bytes(leaf, item);
-               extent_end = extent_start + extent_num_bytes;
-               err = 0;
+               if (found_key.objectid > inode->i_ino ||
+                   found_key.type > BTRFS_EXTENT_DATA_KEY ||
+                   found_key.offset > end)
+                       break;
 
-               if (btrfs_file_extent_compression(leaf, item) ||
-                   btrfs_file_extent_encryption(leaf,item) ||
-                   btrfs_file_extent_other_encoding(leaf, item))
-                       goto not_found;
+               if (found_key.offset > cur_offset) {
+                       extent_end = found_key.offset;
+                       goto out_check;
+               }
 
-               if (loops && start != extent_start)
-                       goto not_found;
+               fi = btrfs_item_ptr(leaf, path->slots[0],
+                                   struct btrfs_file_extent_item);
+               extent_type = btrfs_file_extent_type(leaf, fi);
+
+               if (extent_type == BTRFS_FILE_EXTENT_REG ||
+                   extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
+                       struct btrfs_block_group_cache *block_group;
+                       disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+                       extent_end = found_key.offset +
+                               btrfs_file_extent_num_bytes(leaf, fi);
+                       if (extent_end <= start) {
+                               path->slots[0]++;
+                               goto next_slot;
+                       }
+                       if (btrfs_file_extent_compression(leaf, fi) ||
+                           btrfs_file_extent_encryption(leaf, fi) ||
+                           btrfs_file_extent_other_encoding(leaf, fi))
+                               goto out_check;
+                       if (disk_bytenr == 0)
+                               goto out_check;
+                       if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
+                               goto out_check;
+                       if (btrfs_cross_ref_exist(trans, root, disk_bytenr))
+                               goto out_check;
+                       block_group = btrfs_lookup_block_group(root->fs_info,
+                                                              disk_bytenr);
+                       if (!block_group || block_group->ro)
+                               goto out_check;
+                       disk_bytenr += btrfs_file_extent_offset(leaf, fi);
+                       nocow = 1;
+               } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+                       extent_end = found_key.offset +
+                               btrfs_file_extent_inline_len(leaf, fi);
+                       extent_end = ALIGN(extent_end, root->sectorsize);
+               } else {
+                       BUG_ON(1);
+               }
+out_check:
+               if (extent_end <= start) {
+                       path->slots[0]++;
+                       goto next_slot;
+               }
+               if (!nocow) {
+                       if (cow_start == (u64)-1)
+                               cow_start = cur_offset;
+                       cur_offset = extent_end;
+                       if (cur_offset > end)
+                               break;
+                       path->slots[0]++;
+                       goto next_slot;
+               }
 
-               if (start < extent_start || start >= extent_end)
-                       goto not_found;
+               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,
+                                       nr_written, 1);
+                       BUG_ON(ret);
+                       cow_start = (u64)-1;
+               }
 
-               bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
-               if (bytenr == 0)
-                       goto not_found;
+               disk_bytenr += cur_offset - found_key.offset;
+               num_bytes = min(end + 1, extent_end) - cur_offset;
+               if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
+                       struct extent_map *em;
+                       struct extent_map_tree *em_tree;
+                       em_tree = &BTRFS_I(inode)->extent_tree;
+                       em = alloc_extent_map(GFP_NOFS);
+                       em->start = cur_offset;
+                       em->orig_start = em->start;
+                       em->len = num_bytes;
+                       em->block_len = num_bytes;
+                       em->block_start = disk_bytenr;
+                       em->bdev = root->fs_info->fs_devices->latest_bdev;
+                       set_bit(EXTENT_FLAG_PINNED, &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, em->start,
+                                               em->start + em->len - 1, 0);
+                       }
+                       type = BTRFS_ORDERED_PREALLOC;
+               } else {
+                       type = BTRFS_ORDERED_NOCOW;
+               }
 
-               if (btrfs_cross_ref_exists(trans, root, &found_key, bytenr))
-                       goto not_found;
-               /*
-                * we may be called by the resizer, make sure we're inside
-                * the limits of the FS
-                */
-               block_group = btrfs_lookup_block_group(root->fs_info,
-                                                      bytenr);
-               if (!block_group || block_group->ro)
-                       goto not_found;
+               ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
+                                              num_bytes, num_bytes, type);
+               BUG_ON(ret);
 
-               bytenr += btrfs_file_extent_offset(leaf, item);
-               extent_num_bytes = min(end + 1, extent_end) - start;
-               ret = btrfs_add_ordered_extent(inode, start, bytenr,
-                                               extent_num_bytes,
-                                               extent_num_bytes, 1, 0);
-               if (ret) {
-                       err = ret;
-                       goto out;
-               }
+               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);
+               cur_offset = extent_end;
+               if (cur_offset > end)
+                       break;
+       }
+       btrfs_release_path(root, path);
 
-               btrfs_release_path(root, path);
-               start = extent_end;
-               if (start <= end) {
-                       loops++;
-                       goto again;
-               }
-       } else {
-not_found:
-               btrfs_end_transaction(trans, root);
-               btrfs_free_path(path);
-               return cow_file_range(inode, locked_page, start, end,
-                                     page_started);
+       if (cur_offset <= end && cow_start == (u64)-1)
+               cow_start = cur_offset;
+       if (cow_start != (u64)-1) {
+               ret = cow_file_range(inode, locked_page, cow_start, end,
+                                    page_started, nr_written, 1);
+               BUG_ON(ret);
        }
-out:
-       WARN_ON(err);
-       btrfs_end_transaction(trans, root);
+
+       ret = btrfs_end_transaction(trans, root);
+       BUG_ON(ret);
        btrfs_free_path(path);
-       return err;
+       return 0;
 }
 
 /*
  * 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;
@@ -717,10 +1121,13 @@ 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);
+                                        page_started, 0, nr_written);
+       else if (btrfs_test_flag(inode, PREALLOC))
+               ret = run_delalloc_nocow(inode, locked_page, start, end,
+                                        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;
 }
@@ -792,6 +1199,9 @@ 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;
@@ -812,7 +1222,7 @@ int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
  * At IO completion time the cums attached on the ordered extent record
  * are inserted into the btree
  */
-int __btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
+int __btrfs_submit_bio_start(struct inode *inode, int rw, struct bio *bio,
                          int mirror_num, unsigned long bio_flags)
 {
        struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -820,7 +1230,21 @@ int __btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 
        ret = btrfs_csum_one_bio(root, inode, bio);
        BUG_ON(ret);
+       return 0;
+}
 
+/*
+ * in order to insert checksums into the metadata in large chunks,
+ * we wait until bio submission time.   All the pages in the bio are
+ * checksummed and sums are attached onto the ordered extent record.
+ *
+ * At IO completion time the cums attached on the ordered extent record
+ * are inserted into the btree
+ */
+int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
+                         int mirror_num, unsigned long bio_flags)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
        return btrfs_map_bio(root, rw, bio, mirror_num, 1);
 }
 
@@ -833,28 +1257,30 @@ int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 {
        struct btrfs_root *root = BTRFS_I(inode)->root;
        int ret = 0;
+       int skip_sum;
 
        ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
        BUG_ON(ret);
 
-       if (btrfs_test_opt(root, NODATASUM) ||
-           btrfs_test_flag(inode, NODATASUM)) {
-               goto mapit;
-       }
-
+       skip_sum = btrfs_test_opt(root, NODATASUM) ||
+               btrfs_test_flag(inode, NODATASUM);
+
        if (!(rw & (1 << BIO_RW))) {
-               btrfs_lookup_bio_sums(root, inode, bio);
 
-               if (bio_flags & EXTENT_BIO_COMPRESSED) {
+               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;
-       }
-       return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
+       } else if (!skip_sum) {
+               /* we're doing a write, do the async checksumming */
+               return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
                                   inode, rw, bio, mirror_num,
-                                  bio_flags, __btrfs_submit_bio_hook);
+                                  bio_flags, __btrfs_submit_bio_start,
+                                  __btrfs_submit_bio_done);
+       }
+
 mapit:
        return btrfs_map_bio(root, rw, bio, mirror_num, 0);
 }
@@ -881,6 +1307,9 @@ 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);
 }
@@ -977,6 +1406,63 @@ int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
        return -EAGAIN;
 }
 
+static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
+                                      struct inode *inode, u64 file_pos,
+                                      u64 disk_bytenr, u64 disk_num_bytes,
+                                      u64 num_bytes, u64 ram_bytes,
+                                      u8 compression, u8 encryption,
+                                      u16 other_encoding, int extent_type)
+{
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       struct btrfs_file_extent_item *fi;
+       struct btrfs_path *path;
+       struct extent_buffer *leaf;
+       struct btrfs_key ins;
+       u64 hint;
+       int ret;
+
+       path = btrfs_alloc_path();
+       BUG_ON(!path);
+
+       ret = btrfs_drop_extents(trans, root, inode, file_pos,
+                                file_pos + num_bytes, file_pos, &hint);
+       BUG_ON(ret);
+
+       ins.objectid = inode->i_ino;
+       ins.offset = file_pos;
+       ins.type = BTRFS_EXTENT_DATA_KEY;
+       ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
+       BUG_ON(ret);
+       leaf = path->nodes[0];
+       fi = btrfs_item_ptr(leaf, path->slots[0],
+                           struct btrfs_file_extent_item);
+       btrfs_set_file_extent_generation(leaf, fi, trans->transid);
+       btrfs_set_file_extent_type(leaf, fi, extent_type);
+       btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
+       btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
+       btrfs_set_file_extent_offset(leaf, fi, 0);
+       btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
+       btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
+       btrfs_set_file_extent_compression(leaf, fi, compression);
+       btrfs_set_file_extent_encryption(leaf, fi, encryption);
+       btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
+       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;
+       ins.type = BTRFS_EXTENT_ITEM_KEY;
+       ret = btrfs_alloc_reserved_extent(trans, root, leaf->start,
+                                         root->root_key.objectid,
+                                         trans->transid, inode->i_ino, &ins);
+       BUG_ON(ret);
+
+       btrfs_free_path(path);
+       return 0;
+}
+
 /* as ordered data IO finishes, this gets called so we can finish
  * an ordered extent if the range of bytes in the file it covers are
  * fully written.
@@ -987,12 +1473,7 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
        struct btrfs_trans_handle *trans;
        struct btrfs_ordered_extent *ordered_extent;
        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
-       struct btrfs_file_extent_item *extent_item;
-       struct btrfs_path *path = NULL;
-       struct extent_buffer *leaf;
-       u64 alloc_hint = 0;
-       struct list_head list;
-       struct btrfs_key ins;
+       int compressed = 0;
        int ret;
 
        ret = btrfs_dec_test_ordered_pending(inode, start, end - start + 1);
@@ -1006,70 +1487,30 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
        if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))
                goto nocow;
 
-       path = btrfs_alloc_path();
-       BUG_ON(!path);
-
        lock_extent(io_tree, ordered_extent->file_offset,
                    ordered_extent->file_offset + ordered_extent->len - 1,
                    GFP_NOFS);
 
-       INIT_LIST_HEAD(&list);
-
-       mutex_lock(&BTRFS_I(inode)->extent_mutex);
-
-       ret = btrfs_drop_extents(trans, root, inode,
-                                ordered_extent->file_offset,
-                                ordered_extent->file_offset +
-                                ordered_extent->len,
-                                ordered_extent->file_offset, &alloc_hint);
-       BUG_ON(ret);
-
-       ins.objectid = inode->i_ino;
-       ins.offset = ordered_extent->file_offset;
-       ins.type = BTRFS_EXTENT_DATA_KEY;
-       ret = btrfs_insert_empty_item(trans, root, path, &ins,
-                                     sizeof(*extent_item));
-       BUG_ON(ret);
-       leaf = path->nodes[0];
-       extent_item = btrfs_item_ptr(leaf, path->slots[0],
-                                    struct btrfs_file_extent_item);
-       btrfs_set_file_extent_generation(leaf, extent_item, trans->transid);
-       btrfs_set_file_extent_type(leaf, extent_item, BTRFS_FILE_EXTENT_REG);
-       btrfs_set_file_extent_disk_bytenr(leaf, extent_item,
-                                         ordered_extent->start);
-       btrfs_set_file_extent_disk_num_bytes(leaf, extent_item,
-                                            ordered_extent->disk_len);
-       btrfs_set_file_extent_offset(leaf, extent_item, 0);
-
        if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
-               btrfs_set_file_extent_compression(leaf, extent_item, 1);
-       else
-               btrfs_set_file_extent_compression(leaf, extent_item, 0);
-       btrfs_set_file_extent_encryption(leaf, extent_item, 0);
-       btrfs_set_file_extent_other_encoding(leaf, extent_item, 0);
-
-       /* ram bytes = extent_num_bytes for now */
-       btrfs_set_file_extent_num_bytes(leaf, extent_item,
-                                       ordered_extent->len);
-       btrfs_set_file_extent_ram_bytes(leaf, extent_item,
-                                       ordered_extent->len);
-       btrfs_mark_buffer_dirty(leaf);
-
-       btrfs_drop_extent_cache(inode, ordered_extent->file_offset,
-                               ordered_extent->file_offset +
-                               ordered_extent->len - 1, 0);
-       mutex_unlock(&BTRFS_I(inode)->extent_mutex);
-
-       ins.objectid = ordered_extent->start;
-       ins.offset = ordered_extent->disk_len;
-       ins.type = BTRFS_EXTENT_ITEM_KEY;
-       ret = btrfs_alloc_reserved_extent(trans, root, leaf->start,
-                                         root->root_key.objectid,
-                                         trans->transid, inode->i_ino, &ins);
-       BUG_ON(ret);
-       btrfs_release_path(root, path);
-
-       inode_add_bytes(inode, ordered_extent->len);
+               compressed = 1;
+       if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
+               BUG_ON(compressed);
+               ret = btrfs_mark_extent_written(trans, root, inode,
+                                               ordered_extent->file_offset,
+                                               ordered_extent->file_offset +
+                                               ordered_extent->len);
+               BUG_ON(ret);
+       } else {
+               ret = insert_reserved_file_extent(trans, inode,
+                                               ordered_extent->file_offset,
+                                               ordered_extent->start,
+                                               ordered_extent->disk_len,
+                                               ordered_extent->len,
+                                               ordered_extent->len,
+                                               compressed, 0, 0,
+                                               BTRFS_FILE_EXTENT_REG);
+               BUG_ON(ret);
+       }
        unlock_extent(io_tree, ordered_extent->file_offset,
                    ordered_extent->file_offset + ordered_extent->len - 1,
                    GFP_NOFS);
@@ -1089,8 +1530,6 @@ nocow:
        btrfs_put_ordered_extent(ordered_extent);
 
        btrfs_end_transaction(trans, root);
-       if (path)
-               btrfs_free_path(path);
        return 0;
 }
 
@@ -1369,10 +1808,6 @@ void btrfs_orphan_cleanup(struct btrfs_root *root)
        struct inode *inode;
        int ret = 0, nr_unlink = 0, nr_truncate = 0;
 
-       /* don't do orphan cleanup if the fs is readonly. */
-       if (root->fs_info->sb->s_flags & MS_RDONLY)
-               return;
-
        path = btrfs_alloc_path();
        if (!path)
                return;
@@ -1777,7 +2212,12 @@ static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
        struct btrfs_trans_handle *trans;
        unsigned long nr = 0;
 
-       if (inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
+       /*
+        * the FIRST_FREE_OBJECTID check makes sure we don't try to rmdir
+        * the root of a subvolume or snapshot
+        */
+       if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
+           inode->i_ino == BTRFS_FIRST_FREE_OBJECTID) {
                return -ENOTEMPTY;
        }
 
@@ -2010,6 +2450,7 @@ 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)
@@ -2049,6 +2490,7 @@ 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;
@@ -2061,6 +2503,10 @@ 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);
@@ -2105,7 +2551,7 @@ 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 -
@@ -2295,81 +2741,98 @@ out:
        return ret;
 }
 
-static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
+int btrfs_cont_expand(struct inode *inode, loff_t size)
 {
-       struct inode *inode = dentry->d_inode;
+       struct btrfs_trans_handle *trans;
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+       struct extent_map *em;
+       u64 mask = root->sectorsize - 1;
+       u64 hole_start = (inode->i_size + mask) & ~mask;
+       u64 block_end = (size + mask) & ~mask;
+       u64 last_byte;
+       u64 cur_offset;
+       u64 hole_size;
        int err;
 
-       err = inode_change_ok(inode, attr);
+       if (size <= hole_start)
+               return 0;
+
+       err = btrfs_check_free_space(root, 1, 0);
        if (err)
                return err;
 
-       if (S_ISREG(inode->i_mode) &&
-           attr->ia_valid & ATTR_SIZE && attr->ia_size > inode->i_size) {
-               struct btrfs_trans_handle *trans;
-               struct btrfs_root *root = BTRFS_I(inode)->root;
-               struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
-
-               u64 mask = root->sectorsize - 1;
-               u64 hole_start = (inode->i_size + mask) & ~mask;
-               u64 block_end = (attr->ia_size + mask) & ~mask;
-               u64 hole_size;
-               u64 alloc_hint = 0;
-
-               if (attr->ia_size <= hole_start)
-                       goto out;
+       btrfs_truncate_page(inode->i_mapping, inode->i_size);
 
-               err = btrfs_check_free_space(root, 1, 0);
-               if (err)
-                       goto fail;
+       while (1) {
+               struct btrfs_ordered_extent *ordered;
+               btrfs_wait_ordered_range(inode, hole_start,
+                                        block_end - hole_start);
+               lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+               ordered = btrfs_lookup_ordered_extent(inode, hole_start);
+               if (!ordered)
+                       break;
+               unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+               btrfs_put_ordered_extent(ordered);
+       }
 
-               btrfs_truncate_page(inode->i_mapping, inode->i_size);
+       trans = btrfs_start_transaction(root, 1);
+       btrfs_set_trans_block_group(trans, inode);
 
-               hole_size = block_end - hole_start;
-               while(1) {
-                       struct btrfs_ordered_extent *ordered;
-                       btrfs_wait_ordered_range(inode, hole_start, hole_size);
-
-                       lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
-                       ordered = btrfs_lookup_ordered_extent(inode, hole_start);
-                       if (ordered) {
-                               unlock_extent(io_tree, hole_start,
-                                             block_end - 1, GFP_NOFS);
-                               btrfs_put_ordered_extent(ordered);
-                       } else {
+       cur_offset = hole_start;
+       while (1) {
+               em = btrfs_get_extent(inode, NULL, 0, cur_offset,
+                               block_end - cur_offset, 0);
+               BUG_ON(IS_ERR(em) || !em);
+               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;
-                       }
-               }
-
-               trans = btrfs_start_transaction(root, 1);
-               btrfs_set_trans_block_group(trans, inode);
-               mutex_lock(&BTRFS_I(inode)->extent_mutex);
-               err = btrfs_drop_extents(trans, root, inode,
-                                        hole_start, block_end, hole_start,
-                                        &alloc_hint);
-
-               if (alloc_hint != EXTENT_MAP_INLINE) {
                        err = btrfs_insert_file_extent(trans, root,
-                                                      inode->i_ino,
-                                                      hole_start, 0, 0,
-                                                      hole_size, 0, hole_size,
-                                                      0, 0, 0);
+                                       inode->i_ino, cur_offset, 0,
+                                       0, hole_size, 0, hole_size,
+                                       0, 0, 0);
                        btrfs_drop_extent_cache(inode, hole_start,
-                                               (u64)-1, 0);
-                       btrfs_check_file(root, inode);
+                                       last_byte - 1, 0);
                }
-               mutex_unlock(&BTRFS_I(inode)->extent_mutex);
-               btrfs_end_transaction(trans, root);
-               unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+               free_extent_map(em);
+               cur_offset = last_byte;
+               if (err || cur_offset >= block_end)
+                       break;
+       }
+
+       btrfs_end_transaction(trans, root);
+       unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+       return err;
+}
+
+static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+       struct inode *inode = dentry->d_inode;
+       int err;
+
+       err = inode_change_ok(inode, attr);
+       if (err)
+               return err;
+
+       if (S_ISREG(inode->i_mode) &&
+           attr->ia_valid & ATTR_SIZE && attr->ia_size > inode->i_size) {
+               err = btrfs_cont_expand(inode, attr->ia_size);
                if (err)
                        return err;
        }
-out:
+
        err = inode_setattr(inode, attr);
 
        if (!err && ((attr->ia_valid & ATTR_MODE)))
                err = btrfs_acl_chmod(inode);
-fail:
        return err;
 }
 
@@ -2580,15 +3043,14 @@ struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
        return inode;
 }
 
-static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
-                                  struct nameidata *nd)
+struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
 {
        struct inode * inode;
        struct btrfs_inode *bi = BTRFS_I(dir);
        struct btrfs_root *root = bi->root;
        struct btrfs_root *sub_root = root;
        struct btrfs_key location;
-       int ret, new, do_orphan = 0;
+       int ret, new;
 
        if (dentry->d_name.len > BTRFS_NAME_LEN)
                return ERR_PTR(-ENAMETOOLONG);
@@ -2609,17 +3071,21 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
                inode = btrfs_iget(dir->i_sb, &location, sub_root, &new);
                if (IS_ERR(inode))
                        return ERR_CAST(inode);
-
-               /* the inode and parent dir are two different roots */
-               if (new && root != sub_root) {
-                       igrab(inode);
-                       sub_root->inode = inode;
-                       do_orphan = 1;
-               }
        }
+       return inode;
+}
+
+static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
+                                  struct nameidata *nd)
+{
+       struct inode *inode;
 
-       if (unlikely(do_orphan))
-               btrfs_orphan_cleanup(sub_root);
+       if (dentry->d_name.len > BTRFS_NAME_LEN)
+               return ERR_PTR(-ENAMETOOLONG);
+
+       inode = btrfs_lookup_dentry(dir, dentry);
+       if (IS_ERR(inode))
+               return ERR_CAST(inode);
 
        return d_splice_alias(inode, dentry);
 }
@@ -2675,7 +3141,6 @@ static int btrfs_real_readdir(struct file *filp, void *dirent,
                        return 0;
                filp->f_pos = 2;
        }
-
        path = btrfs_alloc_path();
        path->reada = 2;
 
@@ -2705,6 +3170,7 @@ static int btrfs_real_readdir(struct file *filp, void *dirent,
                                path->slots[0]++;
                        }
                }
+
                advance = 1;
                item = btrfs_item_nr(leaf, slot);
                btrfs_item_key_to_cpu(leaf, &found_key, slot);
@@ -2740,16 +3206,25 @@ static int btrfs_real_readdir(struct file *filp, void *dirent,
 
                        d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
                        btrfs_dir_item_key_to_cpu(leaf, di, &location);
+
+                       /* is this a reference to our own snapshot? If so
+                        * skip it
+                        */
+                       if (location.type == BTRFS_ROOT_ITEM_KEY &&
+                           location.objectid == root->root_key.objectid) {
+                               over = 0;
+                               goto skip;
+                       }
                        over = filldir(dirent, name_ptr, name_len,
                                       found_key.offset, location.objectid,
                                       d_type);
 
+skip:
                        if (name_ptr != tmp_name)
                                kfree(name_ptr);
 
                        if (over)
                                goto nopos;
-
                        di_len = btrfs_dir_name_len(leaf, di) +
                                 btrfs_dir_data_len(leaf, di) + sizeof(*di);
                        di_cur += di_len;
@@ -2775,7 +3250,7 @@ int btrfs_write_inode(struct inode *inode, int wait)
        struct btrfs_trans_handle *trans;
        int ret = 0;
 
-       if (root->fs_info->closing > 1)
+       if (root->fs_info->btree_inode == inode)
                return 0;
 
        if (wait) {
@@ -2864,8 +3339,7 @@ out:
  * helper to find a free sequence number in a given directory.  This current
  * code is very simple, later versions will do smarter things in the btree
  */
-static int btrfs_set_inode_index(struct inode *dir, struct inode *inode,
-                                u64 *index)
+int btrfs_set_inode_index(struct inode *dir, u64 *index)
 {
        int ret = 0;
 
@@ -2911,7 +3385,7 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
                return ERR_PTR(-ENOMEM);
 
        if (dir) {
-               ret = btrfs_set_inode_index(dir, inode, index);
+               ret = btrfs_set_inode_index(dir, index);
                if (ret)
                        return ERR_PTR(ret);
        }
@@ -3197,7 +3671,7 @@ static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
        err = btrfs_check_free_space(root, 1, 0);
        if (err)
                goto fail;
-       err = btrfs_set_inode_index(dir, inode, &index);
+       err = btrfs_set_inode_index(dir, &index);
        if (err)
                goto fail;
 
@@ -3350,7 +3824,7 @@ static noinline int uncompress_inline(struct btrfs_path *path,
 
        read_extent_buffer(leaf, tmp, ptr, inline_size);
 
-       max_size = min(PAGE_CACHE_SIZE, max_size);
+       max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
        ret = btrfs_zlib_decompress(tmp, page, extent_offset,
                                    inline_size, max_size);
        if (ret) {
@@ -3417,6 +3891,7 @@ again:
        }
        em->bdev = root->fs_info->fs_devices->latest_bdev;
        em->start = EXTENT_MAP_HOLE;
+       em->orig_start = EXTENT_MAP_HOLE;
        em->len = (u64)-1;
        em->block_len = (u64)-1;
 
@@ -3452,30 +3927,51 @@ again:
        found_type = btrfs_file_extent_type(leaf, item);
        extent_start = found_key.offset;
        compressed = btrfs_file_extent_compression(leaf, item);
-       if (found_type == BTRFS_FILE_EXTENT_REG) {
+       if (found_type == BTRFS_FILE_EXTENT_REG ||
+           found_type == BTRFS_FILE_EXTENT_PREALLOC) {
                extent_end = extent_start +
                       btrfs_file_extent_num_bytes(leaf, item);
-               err = 0;
-               if (start < extent_start || start >= extent_end) {
-                       em->start = start;
-                       if (start < extent_start) {
-                               if (start + len <= extent_start)
-                                       goto not_found;
-                               em->len = extent_end - extent_start;
-                       } else {
-                               em->len = len;
+       } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+               size_t size;
+               size = btrfs_file_extent_inline_len(leaf, item);
+               extent_end = (extent_start + size + root->sectorsize - 1) &
+                       ~((u64)root->sectorsize - 1);
+       }
+
+       if (start >= extent_end) {
+               path->slots[0]++;
+               if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+                       ret = btrfs_next_leaf(root, path);
+                       if (ret < 0) {
+                               err = ret;
+                               goto out;
                        }
-                       goto not_found_em;
+                       if (ret > 0)
+                               goto not_found;
+                       leaf = path->nodes[0];
                }
+               btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+               if (found_key.objectid != objectid ||
+                   found_key.type != BTRFS_EXTENT_DATA_KEY)
+                       goto not_found;
+               if (start + len <= found_key.offset)
+                       goto not_found;
+               em->start = start;
+               em->len = found_key.offset - start;
+               goto not_found_em;
+       }
+
+       if (found_type == BTRFS_FILE_EXTENT_REG ||
+           found_type == BTRFS_FILE_EXTENT_PREALLOC) {
+               em->start = extent_start;
+               em->len = extent_end - extent_start;
+               em->orig_start = extent_start -
+                                btrfs_file_extent_offset(leaf, item);
                bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
                if (bytenr == 0) {
-                       em->start = extent_start;
-                       em->len = extent_end - extent_start;
                        em->block_start = EXTENT_MAP_HOLE;
                        goto insert;
                }
-               em->start = extent_start;
-               em->len = extent_end - extent_start;
                if (compressed) {
                        set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
                        em->block_start = bytenr;
@@ -3485,46 +3981,32 @@ again:
                        bytenr += btrfs_file_extent_offset(leaf, item);
                        em->block_start = bytenr;
                        em->block_len = em->len;
+                       if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
+                               set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
                }
                goto insert;
        } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
-               u64 page_start;
                unsigned long ptr;
                char *map;
                size_t size;
                size_t extent_offset;
                size_t copy_size;
 
-               size = btrfs_file_extent_inline_len(leaf, item);
-               extent_end = (extent_start + size + root->sectorsize - 1) &
-                       ~((u64)root->sectorsize - 1);
-               if (start < extent_start || start >= extent_end) {
-                       em->start = start;
-                       if (start < extent_start) {
-                               if (start + len <= extent_start)
-                                       goto not_found;
-                               em->len = extent_end - extent_start;
-                       } else {
-                               em->len = len;
-                       }
-                       goto not_found_em;
-               }
                em->block_start = EXTENT_MAP_INLINE;
-
                if (!page || create) {
                        em->start = extent_start;
-                       em->len = (size + root->sectorsize - 1) &
-                       ~((u64)root->sectorsize - 1);
+                       em->len = extent_end - extent_start;
                        goto out;
                }
 
-               page_start = page_offset(page) + pg_offset;
-               extent_offset = page_start - extent_start;
+               size = btrfs_file_extent_inline_len(leaf, item);
+               extent_offset = page_offset(page) + pg_offset - extent_start;
                copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
                                size - extent_offset);
                em->start = extent_start + extent_offset;
                em->len = (copy_size + root->sectorsize - 1) &
                        ~((u64)root->sectorsize - 1);
+               em->orig_start = EXTENT_MAP_INLINE;
                if (compressed)
                        set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
                ptr = btrfs_file_extent_inline_start(item) + extent_offset;
@@ -3569,6 +4051,7 @@ not_found:
        em->len = len;
 not_found_em:
        em->block_start = EXTENT_MAP_HOLE;
+       set_bit(EXTENT_FLAG_VACANCY, &em->flags);
 insert:
        btrfs_release_path(root, path);
        if (em->start > start || extent_map_end(em) <= start) {
@@ -3675,6 +4158,7 @@ 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);
 }
@@ -3885,13 +4369,13 @@ out:
  * Invalidate a single dcache entry at the root of the filesystem.
  * Needed after creation of snapshot or subvolume.
  */
-void btrfs_invalidate_dcache_root(struct btrfs_root *root, char *name,
+void btrfs_invalidate_dcache_root(struct inode *dir, char *name,
                                  int namelen)
 {
        struct dentry *alias, *entry;
        struct qstr qstr;
 
-       alias = d_find_alias(root->fs_info->sb->s_root->d_inode);
+       alias = d_find_alias(dir);
        if (alias) {
                qstr.name = name;
                qstr.len = namelen;
@@ -3923,7 +4407,6 @@ int btrfs_create_subvol_root(struct btrfs_root *new_root, struct dentry *dentry,
                return PTR_ERR(inode);
        inode->i_op = &btrfs_dir_inode_operations;
        inode->i_fop = &btrfs_dir_file_operations;
-       new_root->inode = inode;
 
        inode->i_nlink = 1;
        btrfs_i_size_write(inode, 0);
@@ -4069,6 +4552,7 @@ static int btrfs_getattr(struct vfsmount *mnt,
 {
        struct inode *inode = dentry->d_inode;
        generic_fillattr(inode, stat);
+       stat->dev = BTRFS_I(inode)->root->anon_super.s_dev;
        stat->blksize = PAGE_CACHE_SIZE;
        stat->blocks = (inode_get_bytes(inode) +
                        BTRFS_I(inode)->delalloc_bytes) >> 9;
@@ -4086,6 +4570,11 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
        u64 index = 0;
        int ret;
 
+       /* we're not allowed to rename between subvolumes */
+       if (BTRFS_I(old_inode)->root->root_key.objectid !=
+           BTRFS_I(new_dir)->root->root_key.objectid)
+               return -EXDEV;
+
        if (S_ISDIR(old_inode->i_mode) && new_inode &&
            new_inode->i_size > BTRFS_EMPTY_DIR_SIZE) {
                return -ENOTEMPTY;
@@ -4125,7 +4614,7 @@ static int btrfs_rename(struct inode * old_dir, struct dentry *old_dentry,
                }
 
        }
-       ret = btrfs_set_inode_index(new_dir, old_inode, &index);
+       ret = btrfs_set_inode_index(new_dir, &index);
        if (ret)
                goto out_fail;
 
@@ -4152,6 +4641,9 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root)
        struct inode *inode;
        unsigned long flags;
 
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
+
        spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
        while(!list_empty(head)) {
                binode = list_entry(head->next, struct btrfs_inode,
@@ -4174,9 +4666,11 @@ 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;
@@ -4281,6 +4775,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
        inode->i_op = &btrfs_symlink_inode_operations;
        inode->i_mapping->a_ops = &btrfs_symlink_aops;
        inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
+       inode_set_bytes(inode, name_len);
        btrfs_i_size_write(inode, name_len - 1);
        err = btrfs_update_inode(trans, root, inode);
        if (err)
@@ -4298,6 +4793,130 @@ out_fail:
        return err;
 }
 
+static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
+                              u64 alloc_hint, int mode)
+{
+       struct btrfs_trans_handle *trans;
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       struct btrfs_key ins;
+       u64 alloc_size;
+       u64 cur_offset = start;
+       u64 num_bytes = end - start;
+       int ret = 0;
+
+       trans = btrfs_join_transaction(root, 1);
+       BUG_ON(!trans);
+       btrfs_set_trans_block_group(trans, inode);
+
+       while (num_bytes > 0) {
+               alloc_size = min(num_bytes, root->fs_info->max_extent);
+               ret = btrfs_reserve_extent(trans, root, alloc_size,
+                                          root->sectorsize, 0, alloc_hint,
+                                          (u64)-1, &ins, 1);
+               if (ret) {
+                       WARN_ON(1);
+                       goto out;
+               }
+               ret = insert_reserved_file_extent(trans, inode,
+                                                 cur_offset, ins.objectid,
+                                                 ins.offset, ins.offset,
+                                                 ins.offset, 0, 0, 0,
+                                                 BTRFS_FILE_EXTENT_PREALLOC);
+               BUG_ON(ret);
+               num_bytes -= ins.offset;
+               cur_offset += ins.offset;
+               alloc_hint = ins.objectid + ins.offset;
+       }
+out:
+       if (cur_offset > start) {
+               inode->i_ctime = CURRENT_TIME;
+               btrfs_set_flag(inode, PREALLOC);
+               if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+                   cur_offset > i_size_read(inode))
+                       btrfs_i_size_write(inode, cur_offset);
+               ret = btrfs_update_inode(trans, root, inode);
+               BUG_ON(ret);
+       }
+
+       btrfs_end_transaction(trans, root);
+       return ret;
+}
+
+static long btrfs_fallocate(struct inode *inode, int mode,
+                           loff_t offset, loff_t len)
+{
+       u64 cur_offset;
+       u64 last_byte;
+       u64 alloc_start;
+       u64 alloc_end;
+       u64 alloc_hint = 0;
+       u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
+       struct extent_map *em;
+       int ret;
+
+       alloc_start = offset & ~mask;
+       alloc_end =  (offset + len + mask) & ~mask;
+
+       mutex_lock(&inode->i_mutex);
+       if (alloc_start > inode->i_size) {
+               ret = btrfs_cont_expand(inode, alloc_start);
+               if (ret)
+                       goto out;
+       }
+
+       while (1) {
+               struct btrfs_ordered_extent *ordered;
+               lock_extent(&BTRFS_I(inode)->io_tree, alloc_start,
+                           alloc_end - 1, GFP_NOFS);
+               ordered = btrfs_lookup_first_ordered_extent(inode,
+                                                           alloc_end - 1);
+               if (ordered &&
+                   ordered->file_offset + ordered->len > alloc_start &&
+                   ordered->file_offset < alloc_end) {
+                       btrfs_put_ordered_extent(ordered);
+                       unlock_extent(&BTRFS_I(inode)->io_tree,
+                                     alloc_start, alloc_end - 1, GFP_NOFS);
+                       btrfs_wait_ordered_range(inode, alloc_start,
+                                                alloc_end - alloc_start);
+               } else {
+                       if (ordered)
+                               btrfs_put_ordered_extent(ordered);
+                       break;
+               }
+       }
+
+       cur_offset = alloc_start;
+       while (1) {
+               em = btrfs_get_extent(inode, NULL, 0, cur_offset,
+                                     alloc_end - cur_offset, 0);
+               BUG_ON(IS_ERR(em) || !em);
+               last_byte = min(extent_map_end(em), alloc_end);
+               last_byte = (last_byte + mask) & ~mask;
+               if (em->block_start == EXTENT_MAP_HOLE) {
+                       ret = prealloc_file_range(inode, cur_offset,
+                                       last_byte, alloc_hint, mode);
+                       if (ret < 0) {
+                               free_extent_map(em);
+                               break;
+                       }
+               }
+               if (em->block_start <= EXTENT_MAP_LAST_BYTE)
+                       alloc_hint = em->block_start;
+               free_extent_map(em);
+
+               cur_offset = last_byte;
+               if (cur_offset >= alloc_end) {
+                       ret = 0;
+                       break;
+               }
+       }
+       unlock_extent(&BTRFS_I(inode)->io_tree, alloc_start, alloc_end - 1,
+                     GFP_NOFS);
+out:
+       mutex_unlock(&inode->i_mutex);
+       return ret;
+}
+
 static int btrfs_set_page_dirty(struct page *page)
 {
        return __set_page_dirty_nobuffers(page);
@@ -4311,6 +4930,7 @@ static int btrfs_permission(struct inode *inode, int mask)
 }
 
 static struct inode_operations btrfs_dir_inode_operations = {
+       .getattr        = btrfs_getattr,
        .lookup         = btrfs_lookup,
        .create         = btrfs_create,
        .unlink         = btrfs_unlink,
@@ -4384,6 +5004,7 @@ static struct inode_operations btrfs_file_inode_operations = {
        .listxattr      = btrfs_listxattr,
        .removexattr    = btrfs_removexattr,
        .permission     = btrfs_permission,
+       .fallocate      = btrfs_fallocate,
 };
 static struct inode_operations btrfs_special_inode_operations = {
        .getattr        = btrfs_getattr,