Btrfs: Replace extent tree preallocation code with some bit radix magic.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

5 files changed, 49 insertions, 195 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8b7d01597f4f..59e09e37ab93 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -299,12 +299,7 @@ struct btrfs_fs_info {
         struct radix_tree_root block_group_radix;
         struct radix_tree_root block_group_data_radix;
         struct radix_tree_root extent_map_radix;
-
-        u64 extent_tree_insert[BTRFS_MAX_LEVEL * 6];
-        int extent_tree_insert_nr;
-        u64 extent_tree_prealloc[BTRFS_MAX_LEVEL * 6];
-        int extent_tree_prealloc_nr;
-
+        struct radix_tree_root extent_ins_radix;
         u64 generation;
         struct btrfs_transaction *running_transaction;
         struct btrfs_super_block *disk_super;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c948416fea3a..192211274ce5 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -427,6 +427,7 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         init_bit_radix(&fs_info->pinned_radix);
         init_bit_radix(&fs_info->pending_del_radix);
         init_bit_radix(&fs_info->extent_map_radix);
+        init_bit_radix(&fs_info->extent_ins_radix);
         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
         INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
         INIT_RADIX_TREE(&fs_info->block_group_data_radix, GFP_KERNEL);
@@ -443,8 +444,6 @@ 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;
         fs_info->closing = 0;
 
         INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index f7d76d34fc37..ba50bd7b9a78 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -22,12 +22,6 @@
 #include "print-tree.h"
 #include "transaction.h"
 
-static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
-                            *orig_root, u64 num_blocks, u64 empty_size,
-                            u64 search_start,
-                            u64 search_end, u64 hint_block,
-                            struct btrfs_key *ins, u64 exclude_start,
-                            u64 exclude_nr, int data);
 static int finish_current_insert(struct btrfs_trans_handle *trans, struct
                                  btrfs_root *extent_root);
 static int del_pending_extents(struct btrfs_trans_handle *trans, struct
@@ -174,9 +168,6 @@ static u64 find_search_start(struct btrfs_root *root,
 
         if (cache->data)
                 goto out;
-        if (num > 1) {
-                last = max(last, cache->last_prealloc);
-        }
 again:
         ret = cache_block_group(root, cache);
         if (ret)
@@ -374,18 +365,12 @@ int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
         struct btrfs_key key;
         struct btrfs_leaf *l;
         struct btrfs_extent_item *item;
-        struct btrfs_key ins;
         u32 refs;
 
         path = btrfs_alloc_path();
         if (!path)
                 return -ENOMEM;
-        ret = find_free_extent(trans, root->fs_info->extent_root, 0, 0, 0,
-                               (u64)-1, 0, &ins, 0, 0, 0);
-        if (ret) {
-                btrfs_free_path(path);
-                return ret;
-        }
+
         key.objectid = blocknr;
         key.flags = 0;
         btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
@@ -532,13 +517,7 @@ static int write_one_cache_group(struct btrfs_trans_handle *trans,
         int pending_ret;
         struct btrfs_root *extent_root = root->fs_info->extent_root;
         struct btrfs_block_group_item *bi;
-        struct btrfs_key ins;
 
-        ret = find_free_extent(trans, extent_root, 0, 0, 0, (u64)-1, 0, &ins,
-                               0, 0, 0);
-        /* FIXME, set bit to recalc cache groups on next mount */
-        if (ret)
-                return ret;
         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
         if (ret < 0)
                 goto fail;
@@ -706,14 +685,6 @@ static int update_block_group(struct btrfs_trans_handle *trans,
         return 0;
 }
 
-static int try_remove_page(struct address_space *mapping, unsigned long index)
-{
-        int ret;
-        return 0;
-        ret = invalidate_mapping_pages(mapping, index, index);
-        return ret;
-}
-
 int btrfs_copy_pinned(struct btrfs_root *root, struct radix_tree_root *copy)
 {
         unsigned long gang[8];
@@ -732,6 +703,9 @@ int btrfs_copy_pinned(struct btrfs_root *root, struct radix_tree_root *copy)
                         last = gang[i] + 1;
                 }
         }
+        ret = find_first_radix_bit(&root->fs_info->extent_ins_radix, gang, 0,
+                                   ARRAY_SIZE(gang));
+        WARN_ON(ret);
         return 0;
 }
 
@@ -740,7 +714,6 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
                                struct radix_tree_root *unpin_radix)
 {
         unsigned long gang[8];
-        struct inode *btree_inode = root->fs_info->btree_inode;
         struct btrfs_block_group_cache *block_group;
         u64 first = 0;
         int ret;
@@ -765,14 +738,9 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
                                 block_group->pinned--;
                                 if (gang[i] < block_group->last_alloc)
                                         block_group->last_alloc = gang[i];
-                                if (gang[i] < block_group->last_prealloc)
-                                        block_group->last_prealloc = gang[i];
                                 if (!block_group->data)
                                         set_radix_bit(extent_radix, gang[i]);
                         }
-                        try_remove_page(btree_inode->i_mapping,
-                                        gang[i] << (PAGE_CACHE_SHIFT -
-                                                    btree_inode->i_blkbits));
                 }
         }
         return 0;
@@ -785,7 +753,8 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
         struct btrfs_extent_item extent_item;
         int i;
         int ret;
-        u64 super_blocks_used;
+        int err;
+        unsigned long gang[8];
         struct btrfs_fs_info *info = extent_root->fs_info;
 
         btrfs_set_extent_refs(&extent_item, 1);
@@ -794,16 +763,21 @@ 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->extent_tree_insert_nr; i++) {
-                ins.objectid = extent_root->fs_info->extent_tree_insert[i];
-                super_blocks_used = btrfs_super_blocks_used(&info->super_copy);
-                btrfs_set_super_blocks_used(&info->super_copy,
-                                            super_blocks_used + 1);
-                ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
-                                        sizeof(extent_item));
-                BUG_ON(ret);
+        while(1) {
+                ret = find_first_radix_bit(&info->extent_ins_radix, gang, 0,
+                                           ARRAY_SIZE(gang));
+                if (!ret)
+                        break;
+
+                for (i = 0; i < ret; i++) {
+                        ins.objectid = gang[i];
+                        err = btrfs_insert_item(trans, extent_root, &ins,
+                                                &extent_item,
+                                                sizeof(extent_item));
+                        clear_radix_bit(&info->extent_ins_radix, gang[i]);
+                        WARN_ON(err);
+                }
         }
-        extent_root->fs_info->extent_tree_insert_nr = 0;
         return 0;
 }
 
@@ -856,7 +830,6 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         struct btrfs_root *extent_root = info->extent_root;
         int ret;
         struct btrfs_extent_item *ei;
-        struct btrfs_key ins;
         u32 refs;
 
         key.objectid = blocknr;
@@ -868,12 +841,6 @@ static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         if (!path)
                 return -ENOMEM;
 
-        ret = find_free_extent(trans, root, 0, 0, 0, (u64)-1, 0, &ins, 0, 0, 0);
-        if (ret) {
-                btrfs_free_path(path);
-                return ret;
-        }
-
         ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
         if (ret < 0)
                 return ret;
@@ -1003,35 +970,17 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
         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;
         struct btrfs_block_group_cache *block_group;
         int full_scan = 0;
         int wrapped = 0;
         u64 limit;
 
+        WARN_ON(num_blocks < 1);
         ins->flags = 0;
         btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
 
         level = btrfs_header_level(btrfs_buffer_header(root->node));
-        if (num_blocks == 0) {
-                fill_prealloc = 1;
-                num_blocks = 1;
-                total_needed = (min(level + 1, BTRFS_MAX_LEVEL)) * 6;
-        }
-        if (fill_prealloc) {
-                u64 first;
-                int nr = info->extent_tree_prealloc_nr;
-                first = info->extent_tree_prealloc[nr - 1];
-                if (info->extent_tree_prealloc_nr >= total_needed &&
-                    first >= search_start) {
-                        ins->objectid = info->extent_tree_prealloc[0];
-                        ins->offset = 1;
-                        return 0;
-                }
-                info->extent_tree_prealloc_nr = 0;
-        }
         if (search_end == (u64)-1)
                 search_end = btrfs_super_total_blocks(&info->super_copy);
         if (hint_block) {
@@ -1091,10 +1040,6 @@ 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;
-                        }
                         if (start_found)
                                 limit = last_block +
                                         (block_group->key.offset >> 1);
@@ -1170,67 +1115,21 @@ check_pending:
         }
         for (test_block = ins->objectid;
              test_block < ins->objectid + num_blocks; test_block++) {
-                if (test_radix_bit(&info->pinned_radix, test_block)) {
+                if (test_radix_bit(&info->pinned_radix, test_block) ||
+                    test_radix_bit(&info->extent_ins_radix, test_block)) {
                         search_start = test_block + 1;
                         goto new_group;
                 }
         }
-        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(!full_scan);
-                        goto new_group;
-                }
-        }
-        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;
-                        goto new_group;
-                }
-        }
         if (exclude_nr > 0 && (ins->objectid + num_blocks > exclude_start &&
             ins->objectid < exclude_start + exclude_nr)) {
                 search_start = exclude_start + exclude_nr;
                 goto new_group;
         }
-        if (fill_prealloc) {
-                int nr;
-                test_block = ins->objectid;
-                if (test_block - info->extent_tree_prealloc[total_needed - 1] >=
-                    leaf_range(root)) {
-                        total_found = 0;
-                        info->extent_tree_prealloc_nr = total_found;
-                }
-                while(test_block < ins->objectid + ins->offset &&
-                      total_found < total_needed) {
-                        nr = total_needed - total_found - 1;
-                        BUG_ON(nr < 0);
-                        info->extent_tree_prealloc[nr] = test_block;
-                        total_found++;
-                        test_block++;
-                }
-                if (total_found < total_needed) {
-                        search_start = test_block;
-                        goto new_group;
-                }
-                info->extent_tree_prealloc_nr = total_found;
-        }
         if (!data) {
                 block_group = btrfs_lookup_block_group(info, ins->objectid);
-                if (block_group) {
-                        if (fill_prealloc)
-                                block_group->last_prealloc =
-                                     info->extent_tree_prealloc[total_needed-1];
-                        else
-                                trans->block_group = block_group;
-                }
+                if (block_group)
+                        trans->block_group = block_group;
         }
         ins->offset = num_blocks;
         btrfs_free_path(path);
@@ -1278,85 +1177,41 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
         int pending_ret;
         u64 super_blocks_used;
         u64 search_start = 0;
-        u64 exclude_start = 0;
-        u64 exclude_nr = 0;
         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) {
-                int nr;
-                BUG_ON(info->extent_tree_prealloc_nr == 0);
-                BUG_ON(num_blocks != 1);
-                ins->offset = 1;
-                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;
-                ret = update_block_group(trans, root,
-                                         ins->objectid, ins->offset, 1, 0, 0);
-                WARN_ON(info->extent_tree_insert_nr >
-                        ARRAY_SIZE(info->extent_tree_insert));
-                BUG_ON(ret);
-                return 0;
-        }
-
-        /*
-         * if we're doing a data allocation, preallocate room in the
-         * extent tree first.  This way the extent tree blocks end up
-         * in the correct block group.
-         */
-        if (data) {
-                ret = find_free_extent(trans, root, 0, 0, 0,
-                                       search_end, 0, &prealloc_key, 0, 0, 0);
-                BUG_ON(ret);
-                if (ret)
-                        return ret;
-                exclude_nr = info->extent_tree_prealloc_nr;
-                exclude_start = info->extent_tree_prealloc[exclude_nr - 1];
-        }
-
-        /* do the real allocation */
+        WARN_ON(num_blocks < 1);
         ret = find_free_extent(trans, root, num_blocks, empty_size,
                                search_start, search_end, hint_block, ins,
-                               exclude_start, exclude_nr, data);
+                               trans->alloc_exclude_start,
+                               trans->alloc_exclude_nr, data);
         BUG_ON(ret);
         if (ret)
                 return ret;
 
-        /*
-         * if we're doing a metadata allocation, preallocate space in the
-         * extent tree second.  This way, we don't create a tiny hole
-         * in the allocation map between any unused preallocation blocks
-         * and the metadata block we're actually allocating.  On disk,
-         * it'll go:
-         * [block we've allocated], [used prealloc 1], [ unused prealloc ]
-         * The unused prealloc will get reused the next time around.
-         */
-        if (!data) {
-                exclude_start = ins->objectid;
-                exclude_nr = ins->offset;
-                hint_block = exclude_start + exclude_nr;
-                ret = find_free_extent(trans, root, 0, 0, search_start,
-                                       search_end, hint_block,
-                                       &prealloc_key, exclude_start,
-                                       exclude_nr, 0);
-                BUG_ON(ret);
-                if (ret)
-                        return ret;
-        }
-
         super_blocks_used = btrfs_super_blocks_used(&info->super_copy);
         btrfs_set_super_blocks_used(&info->super_copy, super_blocks_used +
                                     num_blocks);
+
+        if (root == extent_root) {
+                BUG_ON(num_blocks != 1);
+                set_radix_bit(&root->fs_info->extent_ins_radix, ins->objectid);
+                goto update_block;
+        }
+
+        WARN_ON(trans->alloc_exclude_nr);
+        trans->alloc_exclude_start = ins->objectid;
+        trans->alloc_exclude_nr = ins->offset;
         ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
                                 sizeof(extent_item));
 
+        trans->alloc_exclude_start = 0;
+        trans->alloc_exclude_nr = 0;
+
         BUG_ON(ret);
         finish_current_insert(trans, extent_root);
         pending_ret = del_pending_extents(trans, extent_root);
@@ -1366,6 +1221,8 @@ int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
         if (pending_ret) {
                 return pending_ret;
         }
+
+update_block:
         ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
                                  data);
         BUG_ON(ret);
@@ -1750,7 +1607,6 @@ int btrfs_read_block_groups(struct btrfs_root *root)
                 memcpy(&cache->key, &found_key, sizeof(found_key));
                 cache->last_alloc = cache->key.objectid;
                 cache->first_free = cache->key.objectid;
-                cache->last_prealloc = cache->key.objectid;
                 cache->pinned = 0;
                 cache->cached = 0;
 
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 88b0752550b6..e64ecec3f52e 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -109,6 +109,8 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
         h->blocks_reserved = num_blocks;
         h->blocks_used = 0;
         h->block_group = NULL;
+        h->alloc_exclude_nr = 0;
+        h->alloc_exclude_start = 0;
         root->fs_info->running_transaction->use_count++;
         mutex_unlock(&root->fs_info->trans_mutex);
         return h;
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 8b2714e65562..65a395eeca91 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -39,6 +39,8 @@ struct btrfs_trans_handle {
         unsigned long blocks_used;
         struct btrfs_transaction *transaction;
         struct btrfs_block_group_cache *block_group;
+        u64 alloc_exclude_start;
+        u64 alloc_exclude_nr;
 };