3 files changed, 87 insertions, 27 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2d166ca8b104..26d0cdd46f49 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -244,12 +244,17 @@ struct btrfs_fs_info {
         struct btrfs_root *extent_root;
         struct btrfs_root *tree_root;
         struct btrfs_root *dev_root;
-        struct btrfs_key current_insert;
         struct btrfs_key last_insert;
         struct radix_tree_root fs_roots_radix;
         struct radix_tree_root pending_del_radix;
         struct radix_tree_root pinned_radix;
         struct radix_tree_root dev_radix;
+
+        u64 extent_tree_insert[BTRFS_MAX_LEVEL * 3];
+        int extent_tree_insert_nr;
+        u64 extent_tree_prealloc[BTRFS_MAX_LEVEL * 3];
+        int extent_tree_prealloc_nr;
+
         u64 generation;
         struct btrfs_transaction *running_transaction;
         struct btrfs_super_block *disk_super;
@@ -267,8 +272,7 @@ struct btrfs_fs_info {
 
 /*
  * in ram representation of the tree.  extent_root is used for all allocations
- * and for the extent tree extent_root root.  current_insert is used
- * only for the extent tree.
+ * and for the extent tree extent_root root.
  */
 struct btrfs_root {
         struct buffer_head *node;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7aff6bb55d91..956727f015a5 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -542,6 +542,8 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
         fs_info->do_barriers = 1;
+        fs_info->extent_tree_insert_nr = 0;
+        fs_info->extent_tree_prealloc_nr = 0;
         BTRFS_I(fs_info->btree_inode)->root = tree_root;
         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
                sizeof(struct btrfs_key));
@@ -555,7 +557,6 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         }
         mutex_init(&fs_info->trans_mutex);
         mutex_init(&fs_info->fs_mutex);
-        memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 
         __setup_root(sb->s_blocksize, dev_root,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 116519503d0c..e6fe3fd38819 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -169,9 +169,8 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
         btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
         btrfs_set_extent_owner(&extent_item, extent_root->root_key.objectid);
 
-        for (i = 0; i < extent_root->fs_info->current_insert.flags; i++) {
-                ins.objectid = extent_root->fs_info->current_insert.objectid +
-                                i;
+        for (i = 0; i < extent_root->fs_info->extent_tree_insert_nr; i++) {
+                ins.objectid = extent_root->fs_info->extent_tree_insert[i];
                 super_blocks_used = btrfs_super_blocks_used(info->disk_super);
                 btrfs_set_super_blocks_used(info->disk_super,
                                             super_blocks_used + 1);
@@ -179,7 +178,8 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
                                         sizeof(extent_item));
                 BUG_ON(ret);
         }
-        extent_root->fs_info->current_insert.offset = 0;
+        extent_root->fs_info->extent_tree_insert_nr = 0;
+        extent_root->fs_info->extent_tree_prealloc_nr = 0;
         return 0;
 }
 
@@ -349,7 +349,10 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         int start_found;
         struct btrfs_leaf *l;
         struct btrfs_root * root = orig_root->fs_info->extent_root;
+        struct btrfs_fs_info *info = root->fs_info;
         int total_needed = num_blocks;
+        int total_found = 0;
+        int fill_prealloc = 0;
         int level;
 
         path = btrfs_alloc_path();
@@ -357,8 +360,12 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
 
         level = btrfs_header_level(btrfs_buffer_header(root->node));
-        total_needed += (level + 2) * 3;
-        if (root->fs_info->last_insert.objectid == 0 && search_end == (u64)-1) {
+        if (num_blocks == 0) {
+                fill_prealloc = 1;
+                num_blocks = 1;
+                total_needed = min(level + 2, BTRFS_MAX_LEVEL) * 3;
+        }
+        if (info->last_insert.objectid == 0 && search_end == (u64)-1) {
                 struct btrfs_disk_key *last_key;
                 btrfs_init_path(path);
                 ins->objectid = (u64)-1;
@@ -373,8 +380,8 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                 last_key = &l->items[path->slots[0]].key;
                 search_start = btrfs_disk_key_objectid(last_key);
         }
-        if (root->fs_info->last_insert.objectid > search_start)
-                search_start = root->fs_info->last_insert.objectid;
+        if (info->last_insert.objectid > search_start)
+                search_start = info->last_insert.objectid;
 
 check_failed:
         btrfs_init_path(path);
@@ -392,6 +399,10 @@ check_failed:
                 l = btrfs_buffer_leaf(path->nodes[0]);
                 slot = path->slots[0];
                 if (slot >= btrfs_header_nritems(&l->header)) {
+                        if (fill_prealloc) {
+                                info->extent_tree_prealloc_nr = 0;
+                                total_found = 0;
+                        }
                         ret = btrfs_next_leaf(root, path);
                         if (ret == 0)
                                 continue;
@@ -399,13 +410,13 @@ check_failed:
                                 goto error;
                         if (!start_found) {
                                 ins->objectid = search_start;
-                                ins->offset = (u64)-1;
+                                ins->offset = (u64)-1 - search_start;
                                 start_found = 1;
                                 goto check_pending;
                         }
                         ins->objectid = last_block > search_start ?
                                         last_block : search_start;
-                        ins->offset = (u64)-1;
+                        ins->offset = (u64)-1 - ins->objectid;
                         goto check_pending;
                 }
                 btrfs_disk_key_to_cpu(&key, &l->items[slot].key);
@@ -414,7 +425,7 @@ check_failed:
                                 if (last_block < search_start)
                                         last_block = search_start;
                                 hole_size = key.objectid - last_block;
-                                if (hole_size > total_needed) {
+                                if (hole_size > num_blocks) {
                                         ins->objectid = last_block;
                                         ins->offset = hole_size;
                                         goto check_pending;
@@ -433,17 +444,51 @@ check_pending:
         btrfs_release_path(root, path);
         BUG_ON(ins->objectid < search_start);
         for (test_block = ins->objectid;
-             test_block < ins->objectid + total_needed; test_block++) {
-                if (test_radix_bit(&root->fs_info->pinned_radix,
-                                      test_block)) {
+             test_block < ins->objectid + num_blocks; test_block++) {
+                if (test_radix_bit(&info->pinned_radix, test_block)) {
                         search_start = test_block + 1;
                         goto check_failed;
                 }
         }
-        BUG_ON(root->fs_info->current_insert.offset);
-        root->fs_info->current_insert.offset = total_needed - num_blocks;
-        root->fs_info->current_insert.objectid = ins->objectid + num_blocks;
-        root->fs_info->current_insert.flags = 0;
+        if (!fill_prealloc && info->extent_tree_insert_nr) {
+                u64 last =
+                  info->extent_tree_insert[info->extent_tree_insert_nr - 1];
+                if (ins->objectid + num_blocks >
+                    info->extent_tree_insert[0] &&
+                    ins->objectid <= last) {
+                        search_start = last + 1;
+                        WARN_ON(1);
+                        goto check_failed;
+                }
+        }
+        if (!fill_prealloc && info->extent_tree_prealloc_nr) {
+                u64 first =
+                  info->extent_tree_prealloc[info->extent_tree_prealloc_nr - 1];
+                if (ins->objectid + num_blocks > first &&
+                    ins->objectid <= info->extent_tree_prealloc[0]) {
+                        search_start = info->extent_tree_prealloc[0] + 1;
+                        WARN_ON(1);
+                        goto check_failed;
+                }
+        }
+        if (fill_prealloc) {
+                int nr;
+                test_block = ins->objectid;
+                while(test_block < ins->objectid + ins->offset &&
+                      total_found < total_needed) {
+                        nr = total_needed - total_found - 1;
+                        BUG_ON(nr < 0);
+                        root->fs_info->extent_tree_prealloc[nr] =
+                                test_block;
+                        total_found++;
+                        test_block++;
+                }
+                if (total_found < total_needed) {
+                        search_start = test_block;
+                        goto check_failed;
+                }
+                root->fs_info->extent_tree_prealloc_nr = total_found;
+        }
         root->fs_info->last_insert.objectid = ins->objectid;
         ins->offset = num_blocks;
         btrfs_free_path(path);
@@ -472,25 +517,35 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
         struct btrfs_fs_info *info = root->fs_info;
         struct btrfs_root *extent_root = info->extent_root;
         struct btrfs_extent_item extent_item;
+        struct btrfs_key prealloc_key;
 
         btrfs_set_extent_refs(&extent_item, 1);
         btrfs_set_extent_owner(&extent_item, owner);
 
         if (root == extent_root) {
-                BUG_ON(extent_root->fs_info->current_insert.offset == 0);
+                int nr;
+                BUG_ON(info->extent_tree_prealloc_nr == 0);
                 BUG_ON(num_blocks != 1);
-                BUG_ON(extent_root->fs_info->current_insert.flags ==
-                       extent_root->fs_info->current_insert.offset);
                 ins->offset = 1;
-                ins->objectid = extent_root->fs_info->current_insert.objectid +
-                                extent_root->fs_info->current_insert.flags++;
+                info->extent_tree_prealloc_nr--;
+                nr = info->extent_tree_prealloc_nr;
+                ins->objectid = info->extent_tree_prealloc[nr];
+                info->extent_tree_insert[info->extent_tree_insert_nr++] =
+                        ins->objectid;
                 return 0;
         }
+        /* do the real allocation */
         ret = find_free_extent(trans, root, num_blocks, search_start,
                                search_end, ins);
         if (ret)
                 return ret;
 
+        /* then do prealloc for the extent tree */
+        ret = find_free_extent(trans, root, 0, ins->objectid + ins->offset,
+                               search_end, &prealloc_key);
+        if (ret)
+                return ret;
+
         super_blocks_used = btrfs_super_blocks_used(info->disk_super);
         btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
                                     num_blocks);