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>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3b6df71..746a9ac 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1007,8 +1007,8 @@ struct btrfs_root {
        u32 stripesize;
 
        u32 type;
-       u64 highest_inode;
-       u64 last_inode_alloc;
+
+       u64 highest_objectid;
        int ref_cows;
        int track_dirty;
        u64 defrag_trans_start;

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 16dae12..790f4b6 100644 (file)
--- 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;
 }
 

diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 6b627c6..fc6f4a7 100644 (file)
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -177,8 +177,6 @@ int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
 
        ret = btrfs_insert_empty_item(trans, root, path, &key,
                                      sizeof(struct btrfs_inode_item));
-       if (ret == 0 && objectid > root->highest_inode)
-               root->highest_inode = objectid;
        return ret;
 }
 

diff --git a/fs/btrfs/inode-map.c b/fs/btrfs/inode-map.c
index 9abbced..c56eb59 100644 (file)
--- a/fs/btrfs/inode-map.c
+++ b/fs/btrfs/inode-map.c
@@ -43,9 +43,10 @@ int btrfs_find_highest_inode(struct btrfs_root *root, u64 *objectid)
                slot = path->slots[0] - 1;
                l = path->nodes[0];
                btrfs_item_key_to_cpu(l, &found_key, slot);
-               *objectid = found_key.objectid;
+               *objectid = max_t(u64, found_key.objectid,
+                                 BTRFS_FIRST_FREE_OBJECTID - 1);
        } else {
-               *objectid = BTRFS_FIRST_FREE_OBJECTID;
+               *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
        }
        ret = 0;
 error:
@@ -53,91 +54,27 @@ error:
        return ret;
 }
 
-/*
- * walks the btree of allocated inodes and find a hole.
- */
 int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
                             struct btrfs_root *root,
                             u64 dirid, u64 *objectid)
 {
-       struct btrfs_path *path;
-       struct btrfs_key key;
        int ret;
-       int slot = 0;
-       u64 last_ino = 0;
-       int start_found;
-       struct extent_buffer *l;
-       struct btrfs_key search_key;
-       u64 search_start = dirid;
-
        mutex_lock(&root->objectid_mutex);
-       if (root->last_inode_alloc >= BTRFS_FIRST_FREE_OBJECTID &&
-           root->last_inode_alloc < BTRFS_LAST_FREE_OBJECTID) {
-               *objectid = ++root->last_inode_alloc;
-               mutex_unlock(&root->objectid_mutex);
-               return 0;
-       }
-       path = btrfs_alloc_path();
-       BUG_ON(!path);
-       search_start = max(search_start, (u64)BTRFS_FIRST_FREE_OBJECTID);
-       search_key.objectid = search_start;
-       search_key.type = 0;
-       search_key.offset = 0;
-
-       start_found = 0;
-       ret = btrfs_search_slot(trans, root, &search_key, path, 0, 0);
-       if (ret < 0)
-               goto error;
 
-       while (1) {
-               l = path->nodes[0];
-               slot = path->slots[0];
-               if (slot >= btrfs_header_nritems(l)) {
-                       ret = btrfs_next_leaf(root, path);
-                       if (ret == 0)
-                               continue;
-                       if (ret < 0)
-                               goto error;
-                       if (!start_found) {
-                               *objectid = search_start;
-                               start_found = 1;
-                               goto found;
-                       }
-                       *objectid = last_ino > search_start ?
-                               last_ino : search_start;
-                       goto found;
-               }
-               btrfs_item_key_to_cpu(l, &key, slot);
-               if (key.objectid >= search_start) {
-                       if (start_found) {
-                               if (last_ino < search_start)
-                                       last_ino = search_start;
-                               if (key.objectid > last_ino) {
-                                       *objectid = last_ino;
-                                       goto found;
-                               }
-                       } else if (key.objectid > search_start) {
-                               *objectid = search_start;
-                               goto found;
-                       }
-               }
-               if (key.objectid >= BTRFS_LAST_FREE_OBJECTID)
-                       break;
+       if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
+               ret = btrfs_find_highest_inode(root, &root->highest_objectid);
+               if (ret)
+                       goto out;
+       }
 
-               start_found = 1;
-               last_ino = key.objectid + 1;
-               path->slots[0]++;
+       if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
+               ret = -ENOSPC;
+               goto out;
        }
-       BUG_ON(1);
-found:
-       btrfs_release_path(root, path);
-       btrfs_free_path(path);
-       BUG_ON(*objectid < search_start);
-       mutex_unlock(&root->objectid_mutex);
-       return 0;
-error:
-       btrfs_release_path(root, path);
-       btrfs_free_path(path);
+
+       *objectid = ++root->highest_objectid;
+       ret = 0;
+out:
        mutex_unlock(&root->objectid_mutex);
        return ret;
 }

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 81ba665..9e81f31 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3624,9 +3624,6 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
        if (ret != 0)
                goto fail;
 
-       if (objectid > root->highest_inode)
-               root->highest_inode = objectid;
-
        inode->i_uid = current_fsuid();
 
        if (dir && (dir->i_mode & S_ISGID)) {

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index f4a7b62..6e674d7 100644 (file)
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2951,7 +2951,6 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
        struct btrfs_key tmp_key;
        struct btrfs_root *log;
        struct btrfs_fs_info *fs_info = log_root_tree->fs_info;
-       u64 highest_inode;
        struct walk_control wc = {
                .process_func = process_one_buffer,
                .stage = 0,
@@ -3010,11 +3009,6 @@ again:
                                                      path);
                        BUG_ON(ret);
                }
-               ret = btrfs_find_highest_inode(wc.replay_dest, &highest_inode);
-               if (ret == 0) {
-                       wc.replay_dest->highest_inode = highest_inode;
-                       wc.replay_dest->last_inode_alloc = highest_inode;
-               }
 
                key.offset = found_key.offset - 1;
                wc.replay_dest->log_root = NULL;