]> bbs.cooldavid.org Git - net-next-2.6.git/blobdiff - fs/btrfs/transaction.c
Btrfs: Integrate metadata reservation with start_transaction
[net-next-2.6.git] / fs / btrfs / transaction.c
index 21ad37c0519995d19575555717da67664c7daebc..2616491a5c5be1080a925cae2369324e2522d70c 100644 (file)
@@ -165,53 +165,89 @@ enum btrfs_trans_type {
        TRANS_USERSPACE,
 };
 
+static int may_wait_transaction(struct btrfs_root *root, int type)
+{
+       if (!root->fs_info->log_root_recovering &&
+           ((type == TRANS_START && !root->fs_info->open_ioctl_trans) ||
+            type == TRANS_USERSPACE))
+               return 1;
+       return 0;
+}
+
 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
-                                            int num_blocks, int type)
+                                                   u64 num_items, int type)
 {
-       struct btrfs_trans_handle *h =
-               kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
+       struct btrfs_trans_handle *h;
+       struct btrfs_transaction *cur_trans;
+       int retries = 0;
        int ret;
+again:
+       h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
+       if (!h)
+               return ERR_PTR(-ENOMEM);
 
        mutex_lock(&root->fs_info->trans_mutex);
-       if (!root->fs_info->log_root_recovering &&
-           ((type == TRANS_START && !root->fs_info->open_ioctl_trans) ||
-            type == TRANS_USERSPACE))
+       if (may_wait_transaction(root, type))
                wait_current_trans(root);
+
        ret = join_transaction(root);
        BUG_ON(ret);
 
-       h->transid = root->fs_info->running_transaction->transid;
-       h->transaction = root->fs_info->running_transaction;
-       h->blocks_reserved = num_blocks;
+       cur_trans = root->fs_info->running_transaction;
+       cur_trans->use_count++;
+       mutex_unlock(&root->fs_info->trans_mutex);
+
+       h->transid = cur_trans->transid;
+       h->transaction = cur_trans;
        h->blocks_used = 0;
        h->block_group = 0;
+       h->bytes_reserved = 0;
        h->delayed_ref_updates = 0;
        h->block_rsv = NULL;
 
-       if (!current->journal_info && type != TRANS_USERSPACE)
-               current->journal_info = h;
+       smp_mb();
+       if (cur_trans->blocked && may_wait_transaction(root, type)) {
+               btrfs_commit_transaction(h, root);
+               goto again;
+       }
+
+       if (num_items > 0) {
+               ret = btrfs_trans_reserve_metadata(h, root, num_items,
+                                                  &retries);
+               if (ret == -EAGAIN) {
+                       btrfs_commit_transaction(h, root);
+                       goto again;
+               }
+               if (ret < 0) {
+                       btrfs_end_transaction(h, root);
+                       return ERR_PTR(ret);
+               }
+       }
 
-       root->fs_info->running_transaction->use_count++;
+       mutex_lock(&root->fs_info->trans_mutex);
        record_root_in_trans(h, root);
        mutex_unlock(&root->fs_info->trans_mutex);
+
+       if (!current->journal_info && type != TRANS_USERSPACE)
+               current->journal_info = h;
        return h;
 }
 
 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
-                                                  int num_blocks)
+                                                  int num_items)
 {
-       return start_transaction(root, num_blocks, TRANS_START);
+       return start_transaction(root, num_items, TRANS_START);
 }
 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
                                                   int num_blocks)
 {
-       return start_transaction(root, num_blocks, TRANS_JOIN);
+       return start_transaction(root, 0, TRANS_JOIN);
 }
 
 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
                                                         int num_blocks)
 {
-       return start_transaction(r, num_blocks, TRANS_USERSPACE);
+       return start_transaction(r, 0, TRANS_USERSPACE);
 }
 
 /* wait for a transaction commit to be fully complete */
@@ -312,6 +348,8 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
                count++;
        }
 
+       btrfs_trans_release_metadata(trans, root);
+
        mutex_lock(&info->trans_mutex);
        cur_trans = info->running_transaction;
        WARN_ON(cur_trans != trans->transaction);
@@ -757,47 +795,49 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
        struct btrfs_root *root = pending->root;
        struct btrfs_root *parent_root;
        struct inode *parent_inode;
+       struct dentry *dentry;
        struct extent_buffer *tmp;
        struct extent_buffer *old;
        int ret;
-       u64 objectid;
-       int namelen;
        u64 index = 0;
-
-       parent_inode = pending->dentry->d_parent->d_inode;
-       parent_root = BTRFS_I(parent_inode)->root;
+       u64 objectid;
 
        new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
        if (!new_root_item) {
-               ret = -ENOMEM;
+               pending->error = -ENOMEM;
                goto fail;
        }
+
        ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
-       if (ret)
+       if (ret) {
+               pending->error = ret;
                goto fail;
+       }
 
        key.objectid = objectid;
-       /* record when the snapshot was created in key.offset */
-       key.offset = trans->transid;
-       btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+       key.offset = (u64)-1;
+       key.type = BTRFS_ROOT_ITEM_KEY;
 
-       memcpy(&pending->root_key, &key, sizeof(key));
-       pending->root_key.offset = (u64)-1;
+       trans->block_rsv = &pending->block_rsv;
 
+       dentry = pending->dentry;
+       parent_inode = dentry->d_parent->d_inode;
+       parent_root = BTRFS_I(parent_inode)->root;
        record_root_in_trans(trans, parent_root);
+
        /*
         * insert the directory item
         */
-       namelen = strlen(pending->name);
        ret = btrfs_set_inode_index(parent_inode, &index);
        BUG_ON(ret);
        ret = btrfs_insert_dir_item(trans, parent_root,
-                           pending->name, namelen,
-                           parent_inode->i_ino,
-                           &pending->root_key, BTRFS_FT_DIR, index);
+                               dentry->d_name.name, dentry->d_name.len,
+                               parent_inode->i_ino, &key,
+                               BTRFS_FT_DIR, index);
        BUG_ON(ret);
 
-       btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2);
+       btrfs_i_size_write(parent_inode, parent_inode->i_size +
+                                        dentry->d_name.len * 2);
        ret = btrfs_update_inode(trans, parent_root, parent_inode);
        BUG_ON(ret);
 
@@ -814,22 +854,29 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
        free_extent_buffer(old);
 
        btrfs_set_root_node(new_root_item, tmp);
-       ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
-                               new_root_item);
-       BUG_ON(ret);
+       /* record when the snapshot was created in key.offset */
+       key.offset = trans->transid;
+       ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
        btrfs_tree_unlock(tmp);
        free_extent_buffer(tmp);
+       BUG_ON(ret);
 
-       ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
-                                pending->root_key.objectid,
+       /*
+        * insert root back/forward references
+        */
+       ret = btrfs_add_root_ref(trans, tree_root, objectid,
                                 parent_root->root_key.objectid,
-                                parent_inode->i_ino, index, pending->name,
-                                namelen);
+                                parent_inode->i_ino, index,
+                                dentry->d_name.name, dentry->d_name.len);
        BUG_ON(ret);
 
+       key.offset = (u64)-1;
+       pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
+       BUG_ON(IS_ERR(pending->snap));
 fail:
        kfree(new_root_item);
-       return ret;
+       btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
+       return 0;
 }
 
 /*
@@ -898,6 +945,8 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
        ret = btrfs_run_delayed_refs(trans, root, 0);
        BUG_ON(ret);
 
+       btrfs_trans_release_metadata(trans, root);
+
        cur_trans = trans->transaction;
        /*
         * set the flushing flag so procs in this transaction have to