tree-wide: fix assorted typos all over the place
[safe/jmp/linux-2.6] / fs / btrfs / transaction.c
index a320580..bca82a4 100644 (file)
 #include <linux/sched.h>
 #include <linux/writeback.h>
 #include <linux/pagemap.h>
+#include <linux/blkdev.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
-
-static int total_trans = 0;
-extern struct kmem_cache *btrfs_trans_handle_cachep;
-extern struct kmem_cache *btrfs_transaction_cachep;
-
-static struct workqueue_struct *trans_wq;
+#include "locking.h"
+#include "tree-log.h"
 
 #define BTRFS_ROOT_TRANS_TAG 0
-#define BTRFS_ROOT_DEFRAG_TAG 1
 
-static void put_transaction(struct btrfs_transaction *transaction)
+static noinline void put_transaction(struct btrfs_transaction *transaction)
 {
        WARN_ON(transaction->use_count == 0);
        transaction->use_count--;
        if (transaction->use_count == 0) {
-               WARN_ON(total_trans == 0);
-               total_trans--;
                list_del_init(&transaction->list);
                memset(transaction, 0, sizeof(*transaction));
                kmem_cache_free(btrfs_transaction_cachep, transaction);
        }
 }
 
-static int join_transaction(struct btrfs_root *root)
+static noinline void switch_commit_root(struct btrfs_root *root)
+{
+       free_extent_buffer(root->commit_root);
+       root->commit_root = btrfs_root_node(root);
+}
+
+/*
+ * either allocate a new transaction or hop into the existing one
+ */
+static noinline int join_transaction(struct btrfs_root *root)
 {
        struct btrfs_transaction *cur_trans;
        cur_trans = root->fs_info->running_transaction;
        if (!cur_trans) {
                cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
                                             GFP_NOFS);
-               total_trans++;
                BUG_ON(!cur_trans);
                root->fs_info->generation++;
-               root->fs_info->running_transaction = cur_trans;
                cur_trans->num_writers = 1;
                cur_trans->num_joined = 0;
                cur_trans->transid = root->fs_info->generation;
                init_waitqueue_head(&cur_trans->writer_wait);
                init_waitqueue_head(&cur_trans->commit_wait);
                cur_trans->in_commit = 0;
+               cur_trans->blocked = 0;
                cur_trans->use_count = 1;
                cur_trans->commit_done = 0;
                cur_trans->start_time = get_seconds();
+
+               cur_trans->delayed_refs.root.rb_node = NULL;
+               cur_trans->delayed_refs.num_entries = 0;
+               cur_trans->delayed_refs.num_heads_ready = 0;
+               cur_trans->delayed_refs.num_heads = 0;
+               cur_trans->delayed_refs.flushing = 0;
+               cur_trans->delayed_refs.run_delayed_start = 0;
+               spin_lock_init(&cur_trans->delayed_refs.lock);
+
                INIT_LIST_HEAD(&cur_trans->pending_snapshots);
                list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
-               btrfs_ordered_inode_tree_init(&cur_trans->ordered_inode_tree);
-               extent_map_tree_init(&cur_trans->dirty_pages,
+               extent_io_tree_init(&cur_trans->dirty_pages,
                                     root->fs_info->btree_inode->i_mapping,
                                     GFP_NOFS);
+               spin_lock(&root->fs_info->new_trans_lock);
+               root->fs_info->running_transaction = cur_trans;
+               spin_unlock(&root->fs_info->new_trans_lock);
        } else {
                cur_trans->num_writers++;
                cur_trans->num_joined++;
@@ -80,101 +93,292 @@ static int join_transaction(struct btrfs_root *root)
        return 0;
 }
 
-static int record_root_in_trans(struct btrfs_root *root)
+/*
+ * this does all the record keeping required to make sure that a reference
+ * counted root is properly recorded in a given transaction.  This is required
+ * to make sure the old root from before we joined the transaction is deleted
+ * when the transaction commits
+ */
+static noinline int record_root_in_trans(struct btrfs_trans_handle *trans,
+                                        struct btrfs_root *root)
 {
-       u64 running_trans_id = root->fs_info->running_transaction->transid;
-       if (root->ref_cows && root->last_trans < running_trans_id) {
+       if (root->ref_cows && root->last_trans < trans->transid) {
                WARN_ON(root == root->fs_info->extent_root);
-               if (root->root_item.refs != 0) {
-                       radix_tree_tag_set(&root->fs_info->fs_roots_radix,
-                                  (unsigned long)root->root_key.objectid,
-                                  BTRFS_ROOT_TRANS_TAG);
-                       radix_tree_tag_set(&root->fs_info->fs_roots_radix,
-                                  (unsigned long)root->root_key.objectid,
-                                  BTRFS_ROOT_DEFRAG_TAG);
-                       root->commit_root = root->node;
-                       extent_buffer_get(root->node);
-               } else {
-                       WARN_ON(1);
-               }
-               root->last_trans = running_trans_id;
+               WARN_ON(root->commit_root != root->node);
+
+               radix_tree_tag_set(&root->fs_info->fs_roots_radix,
+                          (unsigned long)root->root_key.objectid,
+                          BTRFS_ROOT_TRANS_TAG);
+               root->last_trans = trans->transid;
+               btrfs_init_reloc_root(trans, root);
        }
        return 0;
 }
 
-struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
-                                                  int num_blocks)
+int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *root)
+{
+       if (!root->ref_cows)
+               return 0;
+
+       mutex_lock(&root->fs_info->trans_mutex);
+       if (root->last_trans == trans->transid) {
+               mutex_unlock(&root->fs_info->trans_mutex);
+               return 0;
+       }
+
+       record_root_in_trans(trans, root);
+       mutex_unlock(&root->fs_info->trans_mutex);
+       return 0;
+}
+
+/* wait for commit against the current transaction to become unblocked
+ * when this is done, it is safe to start a new transaction, but the current
+ * transaction might not be fully on disk.
+ */
+static void wait_current_trans(struct btrfs_root *root)
+{
+       struct btrfs_transaction *cur_trans;
+
+       cur_trans = root->fs_info->running_transaction;
+       if (cur_trans && cur_trans->blocked) {
+               DEFINE_WAIT(wait);
+               cur_trans->use_count++;
+               while (1) {
+                       prepare_to_wait(&root->fs_info->transaction_wait, &wait,
+                                       TASK_UNINTERRUPTIBLE);
+                       if (cur_trans->blocked) {
+                               mutex_unlock(&root->fs_info->trans_mutex);
+                               schedule();
+                               mutex_lock(&root->fs_info->trans_mutex);
+                               finish_wait(&root->fs_info->transaction_wait,
+                                           &wait);
+                       } else {
+                               finish_wait(&root->fs_info->transaction_wait,
+                                           &wait);
+                               break;
+                       }
+               }
+               put_transaction(cur_trans);
+       }
+}
+
+static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
+                                            int num_blocks, int wait)
 {
        struct btrfs_trans_handle *h =
                kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
        int ret;
 
        mutex_lock(&root->fs_info->trans_mutex);
+       if (!root->fs_info->log_root_recovering &&
+           ((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2))
+               wait_current_trans(root);
        ret = join_transaction(root);
        BUG_ON(ret);
 
-       record_root_in_trans(root);
        h->transid = root->fs_info->running_transaction->transid;
        h->transaction = root->fs_info->running_transaction;
        h->blocks_reserved = num_blocks;
        h->blocks_used = 0;
-       h->block_group = NULL;
+       h->block_group = 0;
        h->alloc_exclude_nr = 0;
        h->alloc_exclude_start = 0;
+       h->delayed_ref_updates = 0;
+
+       if (!current->journal_info)
+               current->journal_info = h;
+
        root->fs_info->running_transaction->use_count++;
+       record_root_in_trans(h, root);
        mutex_unlock(&root->fs_info->trans_mutex);
        return h;
 }
 
-int btrfs_end_transaction(struct btrfs_trans_handle *trans,
-                         struct btrfs_root *root)
+struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
+                                                  int num_blocks)
 {
-       struct btrfs_transaction *cur_trans;
+       return start_transaction(root, num_blocks, 1);
+}
+struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
+                                                  int num_blocks)
+{
+       return start_transaction(root, num_blocks, 0);
+}
 
+struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
+                                                        int num_blocks)
+{
+       return start_transaction(r, num_blocks, 2);
+}
+
+/* wait for a transaction commit to be fully complete */
+static noinline int wait_for_commit(struct btrfs_root *root,
+                                   struct btrfs_transaction *commit)
+{
+       DEFINE_WAIT(wait);
        mutex_lock(&root->fs_info->trans_mutex);
-       cur_trans = root->fs_info->running_transaction;
+       while (!commit->commit_done) {
+               prepare_to_wait(&commit->commit_wait, &wait,
+                               TASK_UNINTERRUPTIBLE);
+               if (commit->commit_done)
+                       break;
+               mutex_unlock(&root->fs_info->trans_mutex);
+               schedule();
+               mutex_lock(&root->fs_info->trans_mutex);
+       }
+       mutex_unlock(&root->fs_info->trans_mutex);
+       finish_wait(&commit->commit_wait, &wait);
+       return 0;
+}
+
+#if 0
+/*
+ * rate limit against the drop_snapshot code.  This helps to slow down new
+ * operations if the drop_snapshot code isn't able to keep up.
+ */
+static void throttle_on_drops(struct btrfs_root *root)
+{
+       struct btrfs_fs_info *info = root->fs_info;
+       int harder_count = 0;
+
+harder:
+       if (atomic_read(&info->throttles)) {
+               DEFINE_WAIT(wait);
+               int thr;
+               thr = atomic_read(&info->throttle_gen);
+
+               do {
+                       prepare_to_wait(&info->transaction_throttle,
+                                       &wait, TASK_UNINTERRUPTIBLE);
+                       if (!atomic_read(&info->throttles)) {
+                               finish_wait(&info->transaction_throttle, &wait);
+                               break;
+                       }
+                       schedule();
+                       finish_wait(&info->transaction_throttle, &wait);
+               } while (thr == atomic_read(&info->throttle_gen));
+               harder_count++;
+
+               if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
+                   harder_count < 2)
+                       goto harder;
+
+               if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
+                   harder_count < 10)
+                       goto harder;
+
+               if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
+                   harder_count < 20)
+                       goto harder;
+       }
+}
+#endif
+
+void btrfs_throttle(struct btrfs_root *root)
+{
+       mutex_lock(&root->fs_info->trans_mutex);
+       if (!root->fs_info->open_ioctl_trans)
+               wait_current_trans(root);
+       mutex_unlock(&root->fs_info->trans_mutex);
+}
+
+static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
+                         struct btrfs_root *root, int throttle)
+{
+       struct btrfs_transaction *cur_trans;
+       struct btrfs_fs_info *info = root->fs_info;
+       int count = 0;
+
+       while (count < 4) {
+               unsigned long cur = trans->delayed_ref_updates;
+               trans->delayed_ref_updates = 0;
+               if (cur &&
+                   trans->transaction->delayed_refs.num_heads_ready > 64) {
+                       trans->delayed_ref_updates = 0;
+
+                       /*
+                        * do a full flush if the transaction is trying
+                        * to close
+                        */
+                       if (trans->transaction->delayed_refs.flushing)
+                               cur = 0;
+                       btrfs_run_delayed_refs(trans, root, cur);
+               } else {
+                       break;
+               }
+               count++;
+       }
+
+       mutex_lock(&info->trans_mutex);
+       cur_trans = info->running_transaction;
        WARN_ON(cur_trans != trans->transaction);
        WARN_ON(cur_trans->num_writers < 1);
        cur_trans->num_writers--;
+
        if (waitqueue_active(&cur_trans->writer_wait))
                wake_up(&cur_trans->writer_wait);
        put_transaction(cur_trans);
-       mutex_unlock(&root->fs_info->trans_mutex);
+       mutex_unlock(&info->trans_mutex);
+
+       if (current->journal_info == trans)
+               current->journal_info = NULL;
        memset(trans, 0, sizeof(*trans));
        kmem_cache_free(btrfs_trans_handle_cachep, trans);
+
        return 0;
 }
 
+int btrfs_end_transaction(struct btrfs_trans_handle *trans,
+                         struct btrfs_root *root)
+{
+       return __btrfs_end_transaction(trans, root, 0);
+}
 
-int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
-                                    struct btrfs_root *root)
+int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
+                                  struct btrfs_root *root)
+{
+       return __btrfs_end_transaction(trans, root, 1);
+}
+
+/*
+ * when btree blocks are allocated, they have some corresponding bits set for
+ * them in one of two extent_io trees.  This is used to make sure all of
+ * those extents are sent to disk but does not wait on them
+ */
+int btrfs_write_marked_extents(struct btrfs_root *root,
+                              struct extent_io_tree *dirty_pages)
 {
        int ret;
-       int err;
+       int err = 0;
        int werr = 0;
-       struct extent_map_tree *dirty_pages;
        struct page *page;
        struct inode *btree_inode = root->fs_info->btree_inode;
-       u64 start;
+       u64 start = 0;
        u64 end;
        unsigned long index;
 
-       if (!trans || !trans->transaction) {
-               return filemap_write_and_wait(btree_inode->i_mapping);
-       }
-       dirty_pages = &trans->transaction->dirty_pages;
-       while(1) {
-               ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
+       while (1) {
+               ret = find_first_extent_bit(dirty_pages, start, &start, &end,
                                            EXTENT_DIRTY);
                if (ret)
                        break;
-               clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
-               while(start <= end) {
+               while (start <= end) {
+                       cond_resched();
+
                        index = start >> PAGE_CACHE_SHIFT;
                        start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
-                       page = find_lock_page(btree_inode->i_mapping, index);
+                       page = find_get_page(btree_inode->i_mapping, index);
                        if (!page)
                                continue;
+
+                       btree_lock_page_hook(page);
+                       if (!page->mapping) {
+                               unlock_page(page);
+                               page_cache_release(page);
+                               continue;
+                       }
+
                        if (PageWriteback(page)) {
                                if (PageDirty(page))
                                        wait_on_page_writeback(page);
@@ -190,162 +394,225 @@ int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
                        page_cache_release(page);
                }
        }
-       err = filemap_fdatawait(btree_inode->i_mapping);
        if (err)
                werr = err;
        return werr;
 }
 
-int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
-                           struct btrfs_root *root)
+/*
+ * when btree blocks are allocated, they have some corresponding bits set for
+ * them in one of two extent_io trees.  This is used to make sure all of
+ * those extents are on disk for transaction or log commit.  We wait
+ * on all the pages and clear them from the dirty pages state tree
+ */
+int btrfs_wait_marked_extents(struct btrfs_root *root,
+                             struct extent_io_tree *dirty_pages)
 {
        int ret;
-       u64 old_extent_block;
-       struct btrfs_fs_info *fs_info = root->fs_info;
-       struct btrfs_root *tree_root = fs_info->tree_root;
-       struct btrfs_root *extent_root = fs_info->extent_root;
+       int err = 0;
+       int werr = 0;
+       struct page *page;
+       struct inode *btree_inode = root->fs_info->btree_inode;
+       u64 start = 0;
+       u64 end;
+       unsigned long index;
+
+       while (1) {
+               ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
+                                           EXTENT_DIRTY);
+               if (ret)
+                       break;
+
+               clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
+               while (start <= end) {
+                       index = start >> PAGE_CACHE_SHIFT;
+                       start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
+                       page = find_get_page(btree_inode->i_mapping, index);
+                       if (!page)
+                               continue;
+                       if (PageDirty(page)) {
+                               btree_lock_page_hook(page);
+                               wait_on_page_writeback(page);
+                               err = write_one_page(page, 0);
+                               if (err)
+                                       werr = err;
+                       }
+                       wait_on_page_writeback(page);
+                       page_cache_release(page);
+                       cond_resched();
+               }
+       }
+       if (err)
+               werr = err;
+       return werr;
+}
+
+/*
+ * when btree blocks are allocated, they have some corresponding bits set for
+ * them in one of two extent_io trees.  This is used to make sure all of
+ * those extents are on disk for transaction or log commit
+ */
+int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
+                                       struct extent_io_tree *dirty_pages)
+{
+       int ret;
+       int ret2;
 
-       btrfs_write_dirty_block_groups(trans, extent_root);
-       while(1) {
-               old_extent_block = btrfs_root_bytenr(&extent_root->root_item);
-               if (old_extent_block == extent_root->node->start)
+       ret = btrfs_write_marked_extents(root, dirty_pages);
+       ret2 = btrfs_wait_marked_extents(root, dirty_pages);
+       return ret || ret2;
+}
+
+int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
+                                    struct btrfs_root *root)
+{
+       if (!trans || !trans->transaction) {
+               struct inode *btree_inode;
+               btree_inode = root->fs_info->btree_inode;
+               return filemap_write_and_wait(btree_inode->i_mapping);
+       }
+       return btrfs_write_and_wait_marked_extents(root,
+                                          &trans->transaction->dirty_pages);
+}
+
+/*
+ * this is used to update the root pointer in the tree of tree roots.
+ *
+ * But, in the case of the extent allocation tree, updating the root
+ * pointer may allocate blocks which may change the root of the extent
+ * allocation tree.
+ *
+ * So, this loops and repeats and makes sure the cowonly root didn't
+ * change while the root pointer was being updated in the metadata.
+ */
+static int update_cowonly_root(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *root)
+{
+       int ret;
+       u64 old_root_bytenr;
+       struct btrfs_root *tree_root = root->fs_info->tree_root;
+
+       btrfs_write_dirty_block_groups(trans, root);
+
+       while (1) {
+               old_root_bytenr = btrfs_root_bytenr(&root->root_item);
+               if (old_root_bytenr == root->node->start)
                        break;
-               btrfs_set_root_bytenr(&extent_root->root_item,
-                                     extent_root->node->start);
-               btrfs_set_root_level(&extent_root->root_item,
-                                    btrfs_header_level(extent_root->node));
+
+               btrfs_set_root_node(&root->root_item, root->node);
                ret = btrfs_update_root(trans, tree_root,
-                                       &extent_root->root_key,
-                                       &extent_root->root_item);
+                                       &root->root_key,
+                                       &root->root_item);
+               BUG_ON(ret);
+
+               ret = btrfs_write_dirty_block_groups(trans, root);
                BUG_ON(ret);
-               btrfs_write_dirty_block_groups(trans, extent_root);
        }
+
+       if (root != root->fs_info->extent_root)
+               switch_commit_root(root);
+
        return 0;
 }
 
-static int wait_for_commit(struct btrfs_root *root,
-                          struct btrfs_transaction *commit)
+/*
+ * update all the cowonly tree roots on disk
+ */
+static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
+                                        struct btrfs_root *root)
 {
-       DEFINE_WAIT(wait);
-       mutex_lock(&root->fs_info->trans_mutex);
-       while(!commit->commit_done) {
-               prepare_to_wait(&commit->commit_wait, &wait,
-                               TASK_UNINTERRUPTIBLE);
-               if (commit->commit_done)
-                       break;
-               mutex_unlock(&root->fs_info->trans_mutex);
-               schedule();
-               mutex_lock(&root->fs_info->trans_mutex);
+       struct btrfs_fs_info *fs_info = root->fs_info;
+       struct list_head *next;
+       struct extent_buffer *eb;
+       int ret;
+
+       ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+       BUG_ON(ret);
+
+       eb = btrfs_lock_root_node(fs_info->tree_root);
+       btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
+       btrfs_tree_unlock(eb);
+       free_extent_buffer(eb);
+
+       ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+       BUG_ON(ret);
+
+       while (!list_empty(&fs_info->dirty_cowonly_roots)) {
+               next = fs_info->dirty_cowonly_roots.next;
+               list_del_init(next);
+               root = list_entry(next, struct btrfs_root, dirty_list);
+
+               update_cowonly_root(trans, root);
        }
-       mutex_unlock(&root->fs_info->trans_mutex);
-       finish_wait(&commit->commit_wait, &wait);
+
+       down_write(&fs_info->extent_commit_sem);
+       switch_commit_root(fs_info->extent_root);
+       up_write(&fs_info->extent_commit_sem);
+
        return 0;
 }
 
-struct dirty_root {
-       struct list_head list;
-       struct btrfs_root *root;
-       struct btrfs_root *latest_root;
-};
-
-int btrfs_add_dead_root(struct btrfs_root *root,
-                       struct btrfs_root *latest,
-                       struct list_head *dead_list)
+/*
+ * dead roots are old snapshots that need to be deleted.  This allocates
+ * a dirty root struct and adds it into the list of dead roots that need to
+ * be deleted
+ */
+int btrfs_add_dead_root(struct btrfs_root *root)
 {
-       struct dirty_root *dirty;
-
-       dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
-       if (!dirty)
-               return -ENOMEM;
-       dirty->root = root;
-       dirty->latest_root = latest;
-       list_add(&dirty->list, dead_list);
+       mutex_lock(&root->fs_info->trans_mutex);
+       list_add(&root->root_list, &root->fs_info->dead_roots);
+       mutex_unlock(&root->fs_info->trans_mutex);
        return 0;
 }
 
-static int add_dirty_roots(struct btrfs_trans_handle *trans,
-                          struct radix_tree_root *radix,
-                          struct list_head *list)
+/*
+ * update all the cowonly tree roots on disk
+ */
+static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
+                                   struct btrfs_root *root)
 {
-       struct dirty_root *dirty;
        struct btrfs_root *gang[8];
-       struct btrfs_root *root;
+       struct btrfs_fs_info *fs_info = root->fs_info;
        int i;
        int ret;
        int err = 0;
-       u32 refs;
 
-       while(1) {
-               ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
+       while (1) {
+               ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
+                                                (void **)gang, 0,
                                                 ARRAY_SIZE(gang),
                                                 BTRFS_ROOT_TRANS_TAG);
                if (ret == 0)
                        break;
                for (i = 0; i < ret; i++) {
                        root = gang[i];
-                       radix_tree_tag_clear(radix,
-                                    (unsigned long)root->root_key.objectid,
-                                    BTRFS_ROOT_TRANS_TAG);
-                       if (root->commit_root == root->node) {
-                               WARN_ON(root->node->start !=
-                                       btrfs_root_bytenr(&root->root_item));
-                               free_extent_buffer(root->commit_root);
-                               root->commit_root = NULL;
-
-                               /* make sure to update the root on disk
-                                * so we get any updates to the block used
-                                * counts
-                                */
-                               err = btrfs_update_root(trans,
-                                               root->fs_info->tree_root,
-                                               &root->root_key,
-                                               &root->root_item);
-                               continue;
+                       radix_tree_tag_clear(&fs_info->fs_roots_radix,
+                                       (unsigned long)root->root_key.objectid,
+                                       BTRFS_ROOT_TRANS_TAG);
+
+                       btrfs_free_log(trans, root);
+                       btrfs_update_reloc_root(trans, root);
+
+                       if (root->commit_root != root->node) {
+                               switch_commit_root(root);
+                               btrfs_set_root_node(&root->root_item,
+                                                   root->node);
                        }
-                       dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
-                       BUG_ON(!dirty);
-                       dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
-                       BUG_ON(!dirty->root);
-
-                       memset(&root->root_item.drop_progress, 0,
-                              sizeof(struct btrfs_disk_key));
-                       root->root_item.drop_level = 0;
-
-                       memcpy(dirty->root, root, sizeof(*root));
-                       dirty->root->node = root->commit_root;
-                       dirty->latest_root = root;
-                       root->commit_root = NULL;
-
-                       root->root_key.offset = root->fs_info->generation;
-                       btrfs_set_root_bytenr(&root->root_item,
-                                             root->node->start);
-                       btrfs_set_root_level(&root->root_item,
-                                            btrfs_header_level(root->node));
-                       err = btrfs_insert_root(trans, root->fs_info->tree_root,
+
+                       err = btrfs_update_root(trans, fs_info->tree_root,
                                                &root->root_key,
                                                &root->root_item);
                        if (err)
                                break;
-
-                       refs = btrfs_root_refs(&dirty->root->root_item);
-                       btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
-                       err = btrfs_update_root(trans, root->fs_info->tree_root,
-                                               &dirty->root->root_key,
-                                               &dirty->root->root_item);
-
-                       BUG_ON(err);
-                       if (refs == 1) {
-                               list_add(&dirty->list, list);
-                       } else {
-                               WARN_ON(1);
-                               kfree(dirty->root);
-                               kfree(dirty);
-                       }
                }
        }
        return err;
 }
 
+/*
+ * defrag a given btree.  If cacheonly == 1, this won't read from the disk,
+ * otherwise every leaf in the btree is read and defragged.
+ */
 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
 {
        struct btrfs_fs_info *info = root->fs_info;
@@ -353,6 +620,7 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
        struct btrfs_trans_handle *trans;
        unsigned long nr;
 
+       smp_mb();
        if (root->defrag_running)
                return 0;
        trans = btrfs_start_transaction(root, 1);
@@ -361,241 +629,244 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
                ret = btrfs_defrag_leaves(trans, root, cacheonly);
                nr = trans->blocks_used;
                btrfs_end_transaction(trans, root);
-               mutex_unlock(&info->fs_mutex);
                btrfs_btree_balance_dirty(info->tree_root, nr);
                cond_resched();
 
-               mutex_lock(&info->fs_mutex);
                trans = btrfs_start_transaction(root, 1);
-               if (ret != -EAGAIN)
+               if (root->fs_info->closing || ret != -EAGAIN)
                        break;
        }
        root->defrag_running = 0;
-       radix_tree_tag_clear(&info->fs_roots_radix,
-                    (unsigned long)root->root_key.objectid,
-                    BTRFS_ROOT_DEFRAG_TAG);
+       smp_mb();
        btrfs_end_transaction(trans, root);
        return 0;
 }
 
-int btrfs_defrag_dirty_roots(struct btrfs_fs_info *info)
+#if 0
+/*
+ * when dropping snapshots, we generate a ton of delayed refs, and it makes
+ * sense not to join the transaction while it is trying to flush the current
+ * queue of delayed refs out.
+ *
+ * This is used by the drop snapshot code only
+ */
+static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
 {
-       struct btrfs_root *gang[1];
-       struct btrfs_root *root;
-       int i;
-       int ret;
-       int err = 0;
-       u64 last = 0;
+       DEFINE_WAIT(wait);
 
-       while(1) {
-               ret = radix_tree_gang_lookup_tag(&info->fs_roots_radix,
-                                                (void **)gang, last,
-                                                ARRAY_SIZE(gang),
-                                                BTRFS_ROOT_DEFRAG_TAG);
-               if (ret == 0)
-                       break;
-               for (i = 0; i < ret; i++) {
-                       root = gang[i];
-                       last = root->root_key.objectid + 1;
-                       btrfs_defrag_root(root, 1);
-               }
+       mutex_lock(&info->trans_mutex);
+       while (info->running_transaction &&
+              info->running_transaction->delayed_refs.flushing) {
+               prepare_to_wait(&info->transaction_wait, &wait,
+                               TASK_UNINTERRUPTIBLE);
+               mutex_unlock(&info->trans_mutex);
+
+               schedule();
+
+               mutex_lock(&info->trans_mutex);
+               finish_wait(&info->transaction_wait, &wait);
        }
-       btrfs_defrag_root(info->extent_root, 1);
-       return err;
+       mutex_unlock(&info->trans_mutex);
+       return 0;
 }
 
-static int drop_dirty_roots(struct btrfs_root *tree_root,
-                           struct list_head *list)
+/*
+ * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
+ * all of them
+ */
+int btrfs_drop_dead_root(struct btrfs_root *root)
 {
-       struct dirty_root *dirty;
        struct btrfs_trans_handle *trans;
+       struct btrfs_root *tree_root = root->fs_info->tree_root;
        unsigned long nr;
-       u64 num_bytes;
-       u64 bytes_used;
-       int ret = 0;
-       int err;
-
-       while(!list_empty(list)) {
-               struct btrfs_root *root;
-
-               mutex_lock(&tree_root->fs_info->fs_mutex);
-               dirty = list_entry(list->next, struct dirty_root, list);
-               list_del_init(&dirty->list);
+       int ret;
 
-               num_bytes = btrfs_root_used(&dirty->root->root_item);
-               root = dirty->latest_root;
-               root->fs_info->throttles++;
+       while (1) {
+               /*
+                * we don't want to jump in and create a bunch of
+                * delayed refs if the transaction is starting to close
+                */
+               wait_transaction_pre_flush(tree_root->fs_info);
+               trans = btrfs_start_transaction(tree_root, 1);
+
+               /*
+                * we've joined a transaction, make sure it isn't
+                * closing right now
+                */
+               if (trans->transaction->delayed_refs.flushing) {
+                       btrfs_end_transaction(trans, tree_root);
+                       continue;
+               }
 
-               while(1) {
-                       trans = btrfs_start_transaction(tree_root, 1);
-                       ret = btrfs_drop_snapshot(trans, dirty->root);
-                       if (ret != -EAGAIN) {
-                               break;
-                       }
+               ret = btrfs_drop_snapshot(trans, root);
+               if (ret != -EAGAIN)
+                       break;
 
-                       err = btrfs_update_root(trans,
-                                       tree_root,
-                                       &dirty->root->root_key,
-                                       &dirty->root->root_item);
-                       if (err)
-                               ret = err;
-                       nr = trans->blocks_used;
-                       ret = btrfs_end_transaction(trans, tree_root);
-                       BUG_ON(ret);
-                       mutex_unlock(&tree_root->fs_info->fs_mutex);
-                       btrfs_btree_balance_dirty(tree_root, nr);
-                       cond_resched();
-                       mutex_lock(&tree_root->fs_info->fs_mutex);
-               }
-               BUG_ON(ret);
-               root->fs_info->throttles--;
-
-               num_bytes -= btrfs_root_used(&dirty->root->root_item);
-               bytes_used = btrfs_root_used(&root->root_item);
-               if (num_bytes) {
-                       record_root_in_trans(root);
-                       btrfs_set_root_used(&root->root_item,
-                                           bytes_used - num_bytes);
-               }
-               ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
-               if (ret) {
-                       BUG();
+               ret = btrfs_update_root(trans, tree_root,
+                                       &root->root_key,
+                                       &root->root_item);
+               if (ret)
                        break;
-               }
+
                nr = trans->blocks_used;
                ret = btrfs_end_transaction(trans, tree_root);
                BUG_ON(ret);
 
-               free_extent_buffer(dirty->root->node);
-               kfree(dirty->root);
-               kfree(dirty);
-               mutex_unlock(&tree_root->fs_info->fs_mutex);
-
                btrfs_btree_balance_dirty(tree_root, nr);
                cond_resched();
        }
-       return ret;
-}
+       BUG_ON(ret);
 
-int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
-                               struct btrfs_root *root)
-{
-       struct btrfs_transaction *cur_trans = trans->transaction;
-       struct inode *inode;
-       u64 root_objectid = 0;
-       u64 objectid = 0;
-       int ret;
+       ret = btrfs_del_root(trans, tree_root, &root->root_key);
+       BUG_ON(ret);
 
-       root->fs_info->throttles++;
-       while(1) {
-               ret = btrfs_find_first_ordered_inode(
-                               &cur_trans->ordered_inode_tree,
-                               &root_objectid, &objectid);
-               if (!ret)
-                       break;
+       nr = trans->blocks_used;
+       ret = btrfs_end_transaction(trans, tree_root);
+       BUG_ON(ret);
 
-               mutex_unlock(&root->fs_info->trans_mutex);
-               mutex_unlock(&root->fs_info->fs_mutex);
-               inode = btrfs_ilookup(root->fs_info->sb, objectid,
-                                     root_objectid);
-               if (inode) {
-                       if (S_ISREG(inode->i_mode))
-                               filemap_fdatawrite(inode->i_mapping);
-                       iput(inode);
-               }
-               mutex_lock(&root->fs_info->fs_mutex);
-               mutex_lock(&root->fs_info->trans_mutex);
-       }
-       while(1) {
-               root_objectid = 0;
-               objectid = 0;
-               ret = btrfs_find_del_first_ordered_inode(
-                               &cur_trans->ordered_inode_tree,
-                               &root_objectid, &objectid);
-               if (!ret)
-                       break;
-               mutex_unlock(&root->fs_info->trans_mutex);
-               mutex_unlock(&root->fs_info->fs_mutex);
-               inode = btrfs_ilookup(root->fs_info->sb, objectid,
-                                     root_objectid);
-               if (inode) {
-                       if (S_ISREG(inode->i_mode))
-                               filemap_write_and_wait(inode->i_mapping);
-                       iput(inode);
-               }
-               mutex_lock(&root->fs_info->fs_mutex);
-               mutex_lock(&root->fs_info->trans_mutex);
-       }
-       root->fs_info->throttles--;
-       return 0;
+       free_extent_buffer(root->node);
+       free_extent_buffer(root->commit_root);
+       kfree(root);
+
+       btrfs_btree_balance_dirty(tree_root, nr);
+       return ret;
 }
+#endif
 
-static int create_pending_snapshot(struct btrfs_trans_handle *trans,
+/*
+ * new snapshots need to be created at a very specific time in the
+ * transaction commit.  This does the actual creation
+ */
+static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
                                   struct btrfs_fs_info *fs_info,
                                   struct btrfs_pending_snapshot *pending)
 {
        struct btrfs_key key;
-       struct btrfs_root_item new_root_item;
+       struct btrfs_root_item *new_root_item;
        struct btrfs_root *tree_root = fs_info->tree_root;
        struct btrfs_root *root = pending->root;
        struct extent_buffer *tmp;
+       struct extent_buffer *old;
        int ret;
        u64 objectid;
 
+       new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
+       if (!new_root_item) {
+               ret = -ENOMEM;
+               goto fail;
+       }
        ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
        if (ret)
                goto fail;
 
-       memcpy(&new_root_item, &root->root_item, sizeof(new_root_item));
+       record_root_in_trans(trans, root);
+       btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
+       memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
 
        key.objectid = objectid;
-       key.offset = 1;
+       /* record when the snapshot was created in key.offset */
+       key.offset = trans->transid;
        btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
 
-       extent_buffer_get(root->node);
-       btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
-       free_extent_buffer(tmp);
+       old = btrfs_lock_root_node(root);
+       btrfs_cow_block(trans, root, old, NULL, 0, &old);
+       btrfs_set_lock_blocking(old);
 
-       btrfs_copy_root(trans, root, root->node, &tmp, objectid);
+       btrfs_copy_root(trans, root, old, &tmp, objectid);
+       btrfs_tree_unlock(old);
+       free_extent_buffer(old);
 
-       btrfs_set_root_bytenr(&new_root_item, tmp->start);
-       btrfs_set_root_level(&new_root_item, btrfs_header_level(tmp));
+       btrfs_set_root_node(new_root_item, tmp);
        ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
-                               &new_root_item);
+                               new_root_item);
+       btrfs_tree_unlock(tmp);
        free_extent_buffer(tmp);
        if (ret)
                goto fail;
 
+       key.offset = (u64)-1;
+       memcpy(&pending->root_key, &key, sizeof(key));
+fail:
+       kfree(new_root_item);
+       btrfs_unreserve_metadata_space(root, 6);
+       return ret;
+}
+
+static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
+                                  struct btrfs_pending_snapshot *pending)
+{
+       int ret;
+       int namelen;
+       u64 index = 0;
+       struct btrfs_trans_handle *trans;
+       struct inode *parent_inode;
+       struct inode *inode;
+       struct btrfs_root *parent_root;
+
+       parent_inode = pending->dentry->d_parent->d_inode;
+       parent_root = BTRFS_I(parent_inode)->root;
+       trans = btrfs_join_transaction(parent_root, 1);
+
        /*
         * insert the directory item
         */
-       key.offset = (u64)-1;
-       ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
-                                   pending->name, strlen(pending->name),
-                                   root->fs_info->sb->s_root->d_inode->i_ino,
-                                   &key, BTRFS_FT_DIR);
+       namelen = strlen(pending->name);
+       ret = btrfs_set_inode_index(parent_inode, &index);
+       ret = btrfs_insert_dir_item(trans, parent_root,
+                           pending->name, namelen,
+                           parent_inode->i_ino,
+                           &pending->root_key, BTRFS_FT_DIR, index);
 
        if (ret)
                goto fail;
 
-       ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
-                            pending->name, strlen(pending->name), objectid,
-                            root->fs_info->sb->s_root->d_inode->i_ino);
+       btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2);
+       ret = btrfs_update_inode(trans, parent_root, parent_inode);
+       BUG_ON(ret);
+
+       ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
+                                pending->root_key.objectid,
+                                parent_root->root_key.objectid,
+                                parent_inode->i_ino, index, pending->name,
+                                namelen);
+
+       BUG_ON(ret);
+
+       inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
+       d_instantiate(pending->dentry, inode);
 fail:
+       btrfs_end_transaction(trans, fs_info->fs_root);
        return ret;
 }
 
-static int create_pending_snapshots(struct btrfs_trans_handle *trans,
-                                  struct btrfs_fs_info *fs_info)
+/*
+ * create all the snapshots we've scheduled for creation
+ */
+static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
+                                            struct btrfs_fs_info *fs_info)
 {
        struct btrfs_pending_snapshot *pending;
        struct list_head *head = &trans->transaction->pending_snapshots;
        int ret;
 
-       while(!list_empty(head)) {
+       list_for_each_entry(pending, head, list) {
+               ret = create_pending_snapshot(trans, fs_info, pending);
+               BUG_ON(ret);
+       }
+       return 0;
+}
+
+static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans,
+                                            struct btrfs_fs_info *fs_info)
+{
+       struct btrfs_pending_snapshot *pending;
+       struct list_head *head = &trans->transaction->pending_snapshots;
+       int ret;
+
+       while (!list_empty(head)) {
                pending = list_entry(head->next,
                                     struct btrfs_pending_snapshot, list);
-               ret = create_pending_snapshot(trans, fs_info, pending);
+               ret = finish_pending_snapshot(fs_info, pending);
                BUG_ON(ret);
                list_del(&pending->list);
                kfree(pending->name);
@@ -604,6 +875,34 @@ static int create_pending_snapshots(struct btrfs_trans_handle *trans,
        return 0;
 }
 
+static void update_super_roots(struct btrfs_root *root)
+{
+       struct btrfs_root_item *root_item;
+       struct btrfs_super_block *super;
+
+       super = &root->fs_info->super_copy;
+
+       root_item = &root->fs_info->chunk_root->root_item;
+       super->chunk_root = root_item->bytenr;
+       super->chunk_root_generation = root_item->generation;
+       super->chunk_root_level = root_item->level;
+
+       root_item = &root->fs_info->tree_root->root_item;
+       super->root = root_item->bytenr;
+       super->generation = root_item->generation;
+       super->root_level = root_item->level;
+}
+
+int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
+{
+       int ret = 0;
+       spin_lock(&info->new_trans_lock);
+       if (info->running_transaction)
+               ret = info->running_transaction->in_commit;
+       spin_unlock(&info->new_trans_lock);
+       return ret;
+}
+
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root)
 {
@@ -611,21 +910,36 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
        unsigned long timeout = 1;
        struct btrfs_transaction *cur_trans;
        struct btrfs_transaction *prev_trans = NULL;
-       struct list_head dirty_fs_roots;
-       struct extent_map_tree *pinned_copy;
        DEFINE_WAIT(wait);
        int ret;
+       int should_grow = 0;
+       unsigned long now = get_seconds();
+       int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
+
+       btrfs_run_ordered_operations(root, 0);
 
-       INIT_LIST_HEAD(&dirty_fs_roots);
+       /* make a pass through all the delayed refs we have so far
+        * any runnings procs may add more while we are here
+        */
+       ret = btrfs_run_delayed_refs(trans, root, 0);
+       BUG_ON(ret);
+
+       cur_trans = trans->transaction;
+       /*
+        * set the flushing flag so procs in this transaction have to
+        * start sending their work down.
+        */
+       cur_trans->delayed_refs.flushing = 1;
+
+       ret = btrfs_run_delayed_refs(trans, root, 0);
+       BUG_ON(ret);
 
        mutex_lock(&root->fs_info->trans_mutex);
-       if (trans->transaction->in_commit) {
-               cur_trans = trans->transaction;
-               trans->transaction->use_count++;
+       if (cur_trans->in_commit) {
+               cur_trans->use_count++;
                mutex_unlock(&root->fs_info->trans_mutex);
                btrfs_end_transaction(trans, root);
 
-               mutex_unlock(&root->fs_info->fs_mutex);
                ret = wait_for_commit(root, cur_trans);
                BUG_ON(ret);
 
@@ -633,198 +947,192 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                put_transaction(cur_trans);
                mutex_unlock(&root->fs_info->trans_mutex);
 
-               mutex_lock(&root->fs_info->fs_mutex);
                return 0;
        }
 
-       pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
-       if (!pinned_copy)
-               return -ENOMEM;
-
-       extent_map_tree_init(pinned_copy,
-                            root->fs_info->btree_inode->i_mapping, GFP_NOFS);
-
        trans->transaction->in_commit = 1;
-       cur_trans = trans->transaction;
+       trans->transaction->blocked = 1;
        if (cur_trans->list.prev != &root->fs_info->trans_list) {
                prev_trans = list_entry(cur_trans->list.prev,
                                        struct btrfs_transaction, list);
                if (!prev_trans->commit_done) {
                        prev_trans->use_count++;
-                       mutex_unlock(&root->fs_info->fs_mutex);
                        mutex_unlock(&root->fs_info->trans_mutex);
 
                        wait_for_commit(root, prev_trans);
 
-                       mutex_lock(&root->fs_info->fs_mutex);
                        mutex_lock(&root->fs_info->trans_mutex);
                        put_transaction(prev_trans);
                }
        }
 
+       if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
+               should_grow = 1;
+
        do {
+               int snap_pending = 0;
                joined = cur_trans->num_joined;
+               if (!list_empty(&trans->transaction->pending_snapshots))
+                       snap_pending = 1;
+
                WARN_ON(cur_trans != trans->transaction);
                prepare_to_wait(&cur_trans->writer_wait, &wait,
                                TASK_UNINTERRUPTIBLE);
 
                if (cur_trans->num_writers > 1)
                        timeout = MAX_SCHEDULE_TIMEOUT;
-               else
+               else if (should_grow)
                        timeout = 1;
 
-               mutex_unlock(&root->fs_info->fs_mutex);
                mutex_unlock(&root->fs_info->trans_mutex);
 
-               schedule_timeout(timeout);
+               if (flush_on_commit) {
+                       btrfs_start_delalloc_inodes(root);
+                       ret = btrfs_wait_ordered_extents(root, 0);
+                       BUG_ON(ret);
+               } else if (snap_pending) {
+                       ret = btrfs_wait_ordered_extents(root, 1);
+                       BUG_ON(ret);
+               }
+
+               /*
+                * rename don't use btrfs_join_transaction, so, once we
+                * set the transaction to blocked above, we aren't going
+                * to get any new ordered operations.  We can safely run
+                * it here and no for sure that nothing new will be added
+                * to the list
+                */
+               btrfs_run_ordered_operations(root, 1);
+
+               smp_mb();
+               if (cur_trans->num_writers > 1 || should_grow)
+                       schedule_timeout(timeout);
 
-               mutex_lock(&root->fs_info->fs_mutex);
                mutex_lock(&root->fs_info->trans_mutex);
                finish_wait(&cur_trans->writer_wait, &wait);
-               ret = btrfs_write_ordered_inodes(trans, root);
-
        } while (cur_trans->num_writers > 1 ||
-                (cur_trans->num_joined != joined));
+                (should_grow && cur_trans->num_joined != joined));
 
        ret = create_pending_snapshots(trans, root->fs_info);
        BUG_ON(ret);
 
+       ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
+       BUG_ON(ret);
+
        WARN_ON(cur_trans != trans->transaction);
 
-       ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
-                             &dirty_fs_roots);
+       /* btrfs_commit_tree_roots is responsible for getting the
+        * various roots consistent with each other.  Every pointer
+        * in the tree of tree roots has to point to the most up to date
+        * root for every subvolume and other tree.  So, we have to keep
+        * the tree logging code from jumping in and changing any
+        * of the trees.
+        *
+        * At this point in the commit, there can't be any tree-log
+        * writers, but a little lower down we drop the trans mutex
+        * and let new people in.  By holding the tree_log_mutex
+        * from now until after the super is written, we avoid races
+        * with the tree-log code.
+        */
+       mutex_lock(&root->fs_info->tree_log_mutex);
+
+       ret = commit_fs_roots(trans, root);
        BUG_ON(ret);
 
-       ret = btrfs_commit_tree_roots(trans, root);
+       /* commit_fs_roots gets rid of all the tree log roots, it is now
+        * safe to free the root of tree log roots
+        */
+       btrfs_free_log_root_tree(trans, root->fs_info);
+
+       ret = commit_cowonly_roots(trans, root);
        BUG_ON(ret);
 
+       btrfs_prepare_extent_commit(trans, root);
+
        cur_trans = root->fs_info->running_transaction;
        spin_lock(&root->fs_info->new_trans_lock);
        root->fs_info->running_transaction = NULL;
        spin_unlock(&root->fs_info->new_trans_lock);
-       btrfs_set_super_generation(&root->fs_info->super_copy,
-                                  cur_trans->transid);
-       btrfs_set_super_root(&root->fs_info->super_copy,
-                            root->fs_info->tree_root->node->start);
-       btrfs_set_super_root_level(&root->fs_info->super_copy,
-                          btrfs_header_level(root->fs_info->tree_root->node));
 
-       write_extent_buffer(root->fs_info->sb_buffer,
-                           &root->fs_info->super_copy, 0,
-                           sizeof(root->fs_info->super_copy));
+       btrfs_set_root_node(&root->fs_info->tree_root->root_item,
+                           root->fs_info->tree_root->node);
+       switch_commit_root(root->fs_info->tree_root);
+
+       btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
+                           root->fs_info->chunk_root->node);
+       switch_commit_root(root->fs_info->chunk_root);
+
+       update_super_roots(root);
 
-       btrfs_copy_pinned(root, pinned_copy);
+       if (!root->fs_info->log_root_recovering) {
+               btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
+               btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
+       }
+
+       memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
+              sizeof(root->fs_info->super_copy));
+
+       trans->transaction->blocked = 0;
+
+       wake_up(&root->fs_info->transaction_wait);
 
        mutex_unlock(&root->fs_info->trans_mutex);
-       mutex_unlock(&root->fs_info->fs_mutex);
        ret = btrfs_write_and_wait_transaction(trans, root);
        BUG_ON(ret);
-       write_ctree_super(trans, root);
+       write_ctree_super(trans, root, 0);
 
-       mutex_lock(&root->fs_info->fs_mutex);
-       btrfs_finish_extent_commit(trans, root, pinned_copy);
-       mutex_lock(&root->fs_info->trans_mutex);
+       /*
+        * the super is written, we can safely allow the tree-loggers
+        * to go about their business
+        */
+       mutex_unlock(&root->fs_info->tree_log_mutex);
 
-       kfree(pinned_copy);
+       btrfs_finish_extent_commit(trans, root);
+
+       /* do the directory inserts of any pending snapshot creations */
+       finish_pending_snapshots(trans, root->fs_info);
+
+       mutex_lock(&root->fs_info->trans_mutex);
 
        cur_trans->commit_done = 1;
+
        root->fs_info->last_trans_committed = cur_trans->transid;
+
        wake_up(&cur_trans->commit_wait);
+
        put_transaction(cur_trans);
        put_transaction(cur_trans);
 
-       if (root->fs_info->closing)
-               list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
-       else
-               list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
-
        mutex_unlock(&root->fs_info->trans_mutex);
-       kmem_cache_free(btrfs_trans_handle_cachep, trans);
 
-       if (root->fs_info->closing) {
-               mutex_unlock(&root->fs_info->fs_mutex);
-               drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
-               mutex_lock(&root->fs_info->fs_mutex);
-       }
+       if (current->journal_info == trans)
+               current->journal_info = NULL;
+
+       kmem_cache_free(btrfs_trans_handle_cachep, trans);
        return ret;
 }
 
+/*
+ * interface function to delete all the snapshots we have scheduled for deletion
+ */
 int btrfs_clean_old_snapshots(struct btrfs_root *root)
 {
-       struct list_head dirty_roots;
-       INIT_LIST_HEAD(&dirty_roots);
+       LIST_HEAD(list);
+       struct btrfs_fs_info *fs_info = root->fs_info;
 
-       mutex_lock(&root->fs_info->trans_mutex);
-       list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
-       mutex_unlock(&root->fs_info->trans_mutex);
+       mutex_lock(&fs_info->trans_mutex);
+       list_splice_init(&fs_info->dead_roots, &list);
+       mutex_unlock(&fs_info->trans_mutex);
 
-       if (!list_empty(&dirty_roots)) {
-               drop_dirty_roots(root, &dirty_roots);
-       }
-       return 0;
-}
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
-void btrfs_transaction_cleaner(void *p)
-#else
-void btrfs_transaction_cleaner(struct work_struct *work)
-#endif
-{
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
-       struct btrfs_fs_info *fs_info = p;
-#else
-       struct btrfs_fs_info *fs_info = container_of(work,
-                                                    struct btrfs_fs_info,
-                                                    trans_work.work);
+       while (!list_empty(&list)) {
+               root = list_entry(list.next, struct btrfs_root, root_list);
+               list_del(&root->root_list);
 
-#endif
-       struct btrfs_root *root = fs_info->tree_root;
-       struct btrfs_transaction *cur;
-       struct btrfs_trans_handle *trans;
-       unsigned long now;
-       unsigned long delay = HZ * 30;
-       int ret;
-
-       mutex_lock(&root->fs_info->fs_mutex);
-       mutex_lock(&root->fs_info->trans_mutex);
-       cur = root->fs_info->running_transaction;
-       if (!cur) {
-               mutex_unlock(&root->fs_info->trans_mutex);
-               goto out;
-       }
-       now = get_seconds();
-       if (now < cur->start_time || now - cur->start_time < 30) {
-               mutex_unlock(&root->fs_info->trans_mutex);
-               delay = HZ * 5;
-               goto out;
+               if (btrfs_header_backref_rev(root->node) <
+                   BTRFS_MIXED_BACKREF_REV)
+                       btrfs_drop_snapshot(root, 0);
+               else
+                       btrfs_drop_snapshot(root, 1);
        }
-       mutex_unlock(&root->fs_info->trans_mutex);
-       btrfs_defrag_dirty_roots(root->fs_info);
-       trans = btrfs_start_transaction(root, 1);
-       ret = btrfs_commit_transaction(trans, root);
-out:
-       mutex_unlock(&root->fs_info->fs_mutex);
-       btrfs_clean_old_snapshots(root);
-       btrfs_transaction_queue_work(root, delay);
-}
-
-void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
-{
-       queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
-}
-
-void btrfs_transaction_flush_work(struct btrfs_root *root)
-{
-       cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
-       flush_workqueue(trans_wq);
-}
-
-void __init btrfs_init_transaction_sys(void)
-{
-       trans_wq = create_workqueue("btrfs");
-}
-
-void btrfs_exit_transaction_sys(void)
-{
-       destroy_workqueue(trans_wq);
+       return 0;
 }
-