diff options
Diffstat (limited to 'fs/btrfs/transaction.c')
| -rw-r--r-- | fs/btrfs/transaction.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c new file mode 100644 index 00000000000..8dc1c170f10 --- /dev/null +++ b/fs/btrfs/transaction.c @@ -0,0 +1,199 @@ +#include <linux/module.h> +#include <linux/fs.h> +#include "ctree.h" +#include "disk-io.h" +#include "transaction.h" + + +static void put_transaction(struct btrfs_transaction *transaction) +{ + transaction->use_count--; + if (transaction->use_count == 0) + kfree(transaction); +} + +static int join_transaction(struct btrfs_root *root) +{ + struct btrfs_transaction *cur_trans; + cur_trans = root->fs_info->running_transaction; + if (!cur_trans) { + cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS); + BUG_ON(!cur_trans); + root->fs_info->running_transaction = cur_trans; + cur_trans->num_writers = 0; + cur_trans->transid = root->root_key.offset + 1; + init_waitqueue_head(&cur_trans->writer_wait); + init_waitqueue_head(&cur_trans->commit_wait); + cur_trans->in_commit = 0; + cur_trans->use_count = 0; + cur_trans->commit_done = 0; + } + cur_trans->num_writers++; + return 0; +} + +struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, + int num_blocks) +{ + struct btrfs_trans_handle *h = kmalloc(sizeof(*h), GFP_NOFS); + int ret; + + mutex_lock(&root->fs_info->trans_mutex); + 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; + h->blocks_used = 0; + root->fs_info->running_transaction->use_count++; + mutex_unlock(&root->fs_info->trans_mutex); + return h; +} + +int btrfs_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + struct btrfs_transaction *cur_trans; + mutex_lock(&root->fs_info->trans_mutex); + cur_trans = root->fs_info->running_transaction; + WARN_ON(cur_trans->num_writers <= 1); + if (waitqueue_active(&cur_trans->writer_wait)) + wake_up(&cur_trans->writer_wait); + cur_trans->num_writers--; + put_transaction(cur_trans); + mutex_unlock(&root->fs_info->trans_mutex); + kfree(trans); + return 0; +} + + +int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + filemap_write_and_wait(root->fs_info->sb->s_bdev->bd_inode->i_mapping); + return 0; +} + +int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + int ret; + u64 old_extent_block; + struct btrfs_fs_info *fs_info = root->fs_info; + struct btrfs_root *tree_root = fs_info->tree_root; + struct btrfs_root *extent_root = fs_info->extent_root; + struct btrfs_root *inode_root = fs_info->inode_root; + + btrfs_set_root_blocknr(&inode_root->root_item, + inode_root->node->b_blocknr); + ret = btrfs_update_root(trans, tree_root, + &inode_root->root_key, + &inode_root->root_item); + BUG_ON(ret); + while(1) { + old_extent_block = btrfs_root_blocknr(&extent_root->root_item); + if (old_extent_block == extent_root->node->b_blocknr) + break; + btrfs_set_root_blocknr(&extent_root->root_item, + extent_root->node->b_blocknr); + ret = btrfs_update_root(trans, tree_root, + &extent_root->root_key, + &extent_root->root_item); + BUG_ON(ret); + } + return 0; +} + +static int wait_for_commit(struct btrfs_root *root, + struct btrfs_transaction *commit) +{ + DEFINE_WAIT(wait); + commit->use_count++; + while(!commit->commit_done) { + prepare_to_wait(&commit->commit_wait, &wait, + TASK_UNINTERRUPTIBLE); + if (commit->commit_done) + break; + mutex_unlock(&root->fs_info->trans_mutex); + schedule(); + mutex_lock(&root->fs_info->trans_mutex); + } + finish_wait(&commit->commit_wait, &wait); + return 0; +} + +int btrfs_commit_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + int ret = 0; + struct buffer_head *snap = root->commit_root; + struct btrfs_key snap_key; + struct btrfs_transaction *cur_trans; + DEFINE_WAIT(wait); + + mutex_lock(&root->fs_info->trans_mutex); + if (trans->transaction->in_commit) { + cur_trans = trans->transaction; + trans->transaction->use_count++; + btrfs_end_transaction(trans, root); + ret = wait_for_commit(root, cur_trans); + BUG_ON(ret); + put_transaction(cur_trans); + mutex_unlock(&root->fs_info->trans_mutex); + return 0; + } + while (trans->transaction->num_writers > 1) { + prepare_to_wait(&trans->transaction->writer_wait, &wait, + TASK_UNINTERRUPTIBLE); + if (trans->transaction->num_writers <= 1) + break; + mutex_unlock(&root->fs_info->trans_mutex); + schedule(); + mutex_lock(&root->fs_info->trans_mutex); + } + finish_wait(&trans->transaction->writer_wait, &wait); + + cur_trans = root->fs_info->running_transaction; + root->fs_info->running_transaction = NULL; + mutex_unlock(&root->fs_info->trans_mutex); + + memcpy(&snap_key, &root->root_key, sizeof(snap_key)); + root->root_key.offset++; + + if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) { + btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr); + ret = btrfs_insert_root(trans, root->fs_info->tree_root, + &root->root_key, &root->root_item); + BUG_ON(ret); + } + + ret = btrfs_commit_tree_roots(trans, root); + BUG_ON(ret); + + ret = btrfs_write_and_wait_transaction(trans, root); + BUG_ON(ret); + + write_ctree_super(trans, root); + btrfs_finish_extent_commit(trans, root->fs_info->extent_root); + btrfs_finish_extent_commit(trans, root->fs_info->tree_root); + put_transaction(cur_trans); + kfree(trans); + + if (root->node != root->commit_root) { + trans = btrfs_start_transaction(root, 1); + root->commit_root = root->node; + get_bh(root->node); + ret = btrfs_drop_snapshot(trans, root, snap); + BUG_ON(ret); + + ret = btrfs_del_root(trans, root->fs_info->tree_root, + &snap_key); + BUG_ON(ret); + root->fs_info->generation = root->root_key.offset + 1; + ret = btrfs_end_transaction(trans, root); + BUG_ON(ret); + } + + return ret; +} + |