Btrfs: do not reuse objectid of deleted snapshot/subvol

The new back reference format does not allow reusing objectid of
deleted snapshot/subvol. So we use ++highest_objectid to allocate
objectid for new snapshot/subvol.

Now we use ++highest_objectid to allocate objectid for both new inode
and new snapshot/subvolume, so this patch removes 'find hole' code in
btrfs_find_free_objectid.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 14 insertions, 25 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 16dae122dda4..790f4b61a3d7 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -895,8 +895,7 @@ static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
         root->fs_info = fs_info;
         root->objectid = objectid;
         root->last_trans = 0;
-        root->highest_inode = 0;
-        root->last_inode_alloc = 0;
+        root->highest_objectid = 0;
         root->name = NULL;
         root->in_sysfs = 0;
         root->inode_tree.rb_node = NULL;
@@ -1095,7 +1094,6 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
         struct btrfs_fs_info *fs_info = tree_root->fs_info;
         struct btrfs_path *path;
         struct extent_buffer *l;
-        u64 highest_inode;
         u64 generation;
         u32 blocksize;
         int ret = 0;
@@ -1110,7 +1108,7 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
                         kfree(root);
                         return ERR_PTR(ret);
                 }
-                goto insert;
+                goto out;
         }
 
         __setup_root(tree_root->nodesize, tree_root->leafsize,
@@ -1120,39 +1118,30 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
         path = btrfs_alloc_path();
         BUG_ON(!path);
         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
-        if (ret != 0) {
-                if (ret > 0)
-                        ret = -ENOENT;
-                goto out;
+        if (ret == 0) {
+                l = path->nodes[0];
+                read_extent_buffer(l, &root->root_item,
+                                btrfs_item_ptr_offset(l, path->slots[0]),
+                                sizeof(root->root_item));
+                memcpy(&root->root_key, location, sizeof(*location));
         }
-        l = path->nodes[0];
-        read_extent_buffer(l, &root->root_item,
-               btrfs_item_ptr_offset(l, path->slots[0]),
-               sizeof(root->root_item));
-        memcpy(&root->root_key, location, sizeof(*location));
-        ret = 0;
-out:
-        btrfs_release_path(root, path);
         btrfs_free_path(path);
         if (ret) {
-                kfree(root);
+                if (ret > 0)
+                        ret = -ENOENT;
                 return ERR_PTR(ret);
         }
+
         generation = btrfs_root_generation(&root->root_item);
         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
                                      blocksize, generation);
         root->commit_root = btrfs_root_node(root);
         BUG_ON(!root->node);
-insert:
-        if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
+out:
+        if (location->objectid != BTRFS_TREE_LOG_OBJECTID)
                 root->ref_cows = 1;
-                ret = btrfs_find_highest_inode(root, &highest_inode);
-                if (ret == 0) {
-                        root->highest_inode = highest_inode;
-                        root->last_inode_alloc = highest_inode;
-                }
-        }
+
         return root;
 }