225 lines
6.5 KiB
C
225 lines
6.5 KiB
C
#include <linux/module.h>
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#include <linux/fs.h>
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#include "ctree.h"
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#include "disk-io.h"
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#include "transaction.h"
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static int total_trans = 0;
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extern struct kmem_cache *btrfs_trans_handle_cachep;
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extern struct kmem_cache *btrfs_transaction_cachep;
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#define TRANS_MAGIC 0xE1E10E
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static void put_transaction(struct btrfs_transaction *transaction)
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{
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WARN_ON(transaction->use_count == 0);
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transaction->use_count--;
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WARN_ON(transaction->magic != TRANS_MAGIC);
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if (transaction->use_count == 0) {
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WARN_ON(total_trans == 0);
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total_trans--;
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memset(transaction, 0, sizeof(*transaction));
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kmem_cache_free(btrfs_transaction_cachep, transaction);
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}
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}
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static int join_transaction(struct btrfs_root *root)
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{
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struct btrfs_transaction *cur_trans;
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cur_trans = root->fs_info->running_transaction;
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if (!cur_trans) {
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cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
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GFP_NOFS);
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total_trans++;
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BUG_ON(!cur_trans);
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root->fs_info->running_transaction = cur_trans;
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cur_trans->num_writers = 0;
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cur_trans->transid = root->root_key.offset + 1;
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init_waitqueue_head(&cur_trans->writer_wait);
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init_waitqueue_head(&cur_trans->commit_wait);
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cur_trans->magic = TRANS_MAGIC;
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cur_trans->in_commit = 0;
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cur_trans->use_count = 1;
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cur_trans->commit_done = 0;
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}
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cur_trans->num_writers++;
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return 0;
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}
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struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
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int num_blocks)
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{
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struct btrfs_trans_handle *h =
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kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
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int ret;
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mutex_lock(&root->fs_info->trans_mutex);
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ret = join_transaction(root);
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BUG_ON(ret);
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h->transid = root->fs_info->running_transaction->transid;
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h->transaction = root->fs_info->running_transaction;
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h->blocks_reserved = num_blocks;
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h->blocks_used = 0;
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root->fs_info->running_transaction->use_count++;
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mutex_unlock(&root->fs_info->trans_mutex);
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h->magic = h->magic2 = TRANS_MAGIC;
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return h;
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}
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int btrfs_end_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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struct btrfs_transaction *cur_trans;
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WARN_ON(trans->magic != TRANS_MAGIC);
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WARN_ON(trans->magic2 != TRANS_MAGIC);
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mutex_lock(&root->fs_info->trans_mutex);
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cur_trans = root->fs_info->running_transaction;
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WARN_ON(cur_trans->num_writers < 1);
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if (waitqueue_active(&cur_trans->writer_wait))
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wake_up(&cur_trans->writer_wait);
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cur_trans->num_writers--;
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put_transaction(cur_trans);
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mutex_unlock(&root->fs_info->trans_mutex);
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memset(trans, 0, sizeof(*trans));
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kmem_cache_free(btrfs_trans_handle_cachep, trans);
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return 0;
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}
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int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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filemap_write_and_wait(root->fs_info->sb->s_bdev->bd_inode->i_mapping);
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return 0;
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}
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int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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int ret;
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u64 old_extent_block;
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struct btrfs_fs_info *fs_info = root->fs_info;
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struct btrfs_root *tree_root = fs_info->tree_root;
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struct btrfs_root *extent_root = fs_info->extent_root;
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struct btrfs_root *inode_root = fs_info->inode_root;
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btrfs_set_root_blocknr(&inode_root->root_item,
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inode_root->node->b_blocknr);
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ret = btrfs_update_root(trans, tree_root,
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&inode_root->root_key,
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&inode_root->root_item);
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BUG_ON(ret);
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while(1) {
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old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
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if (old_extent_block == extent_root->node->b_blocknr)
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break;
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btrfs_set_root_blocknr(&extent_root->root_item,
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extent_root->node->b_blocknr);
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ret = btrfs_update_root(trans, tree_root,
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&extent_root->root_key,
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&extent_root->root_item);
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BUG_ON(ret);
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}
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return 0;
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}
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static int wait_for_commit(struct btrfs_root *root,
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struct btrfs_transaction *commit)
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{
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DEFINE_WAIT(wait);
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while(!commit->commit_done) {
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prepare_to_wait(&commit->commit_wait, &wait,
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TASK_UNINTERRUPTIBLE);
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if (commit->commit_done)
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break;
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mutex_unlock(&root->fs_info->trans_mutex);
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schedule();
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mutex_lock(&root->fs_info->trans_mutex);
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}
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finish_wait(&commit->commit_wait, &wait);
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return 0;
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}
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int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
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struct btrfs_root *root)
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{
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int ret = 0;
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struct buffer_head *snap;
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struct btrfs_key snap_key;
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struct btrfs_transaction *cur_trans;
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DEFINE_WAIT(wait);
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mutex_lock(&root->fs_info->trans_mutex);
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if (trans->transaction->in_commit) {
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printk("already in commit!, waiting\n");
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cur_trans = trans->transaction;
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trans->transaction->use_count++;
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btrfs_end_transaction(trans, root);
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ret = wait_for_commit(root, cur_trans);
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BUG_ON(ret);
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put_transaction(cur_trans);
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mutex_unlock(&root->fs_info->trans_mutex);
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return 0;
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}
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cur_trans = trans->transaction;
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trans->transaction->in_commit = 1;
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while (trans->transaction->num_writers > 1) {
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WARN_ON(cur_trans != trans->transaction);
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prepare_to_wait(&trans->transaction->writer_wait, &wait,
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TASK_UNINTERRUPTIBLE);
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if (trans->transaction->num_writers <= 1)
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break;
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mutex_unlock(&root->fs_info->trans_mutex);
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schedule();
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mutex_lock(&root->fs_info->trans_mutex);
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finish_wait(&trans->transaction->writer_wait, &wait);
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}
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finish_wait(&trans->transaction->writer_wait, &wait);
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WARN_ON(cur_trans != trans->transaction);
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if (root->node != root->commit_root) {
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memcpy(&snap_key, &root->root_key, sizeof(snap_key));
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root->root_key.offset++;
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}
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if (btrfs_root_blocknr(&root->root_item) != root->node->b_blocknr) {
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btrfs_set_root_blocknr(&root->root_item, root->node->b_blocknr);
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ret = btrfs_insert_root(trans, root->fs_info->tree_root,
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&root->root_key, &root->root_item);
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BUG_ON(ret);
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}
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ret = btrfs_commit_tree_roots(trans, root);
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BUG_ON(ret);
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cur_trans = root->fs_info->running_transaction;
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root->fs_info->running_transaction = NULL;
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mutex_unlock(&root->fs_info->trans_mutex);
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ret = btrfs_write_and_wait_transaction(trans, root);
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BUG_ON(ret);
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write_ctree_super(trans, root);
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btrfs_finish_extent_commit(trans, root);
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mutex_lock(&root->fs_info->trans_mutex);
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cur_trans->commit_done = 1;
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wake_up(&cur_trans->commit_wait);
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put_transaction(cur_trans);
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put_transaction(cur_trans);
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mutex_unlock(&root->fs_info->trans_mutex);
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kmem_cache_free(btrfs_trans_handle_cachep, trans);
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if (root->node != root->commit_root) {
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trans = btrfs_start_transaction(root, 1);
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snap = root->commit_root;
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root->commit_root = root->node;
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get_bh(root->node);
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ret = btrfs_drop_snapshot(trans, root, snap);
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BUG_ON(ret);
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ret = btrfs_del_root(trans, root->fs_info->tree_root,
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&snap_key);
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BUG_ON(ret);
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root->fs_info->generation = root->root_key.offset + 1;
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ret = btrfs_end_transaction(trans, root);
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BUG_ON(ret);
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}
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return ret;
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}
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