mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
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2619ba1f0f
Signed-off-by: Chris Mason <chris.mason@oracle.com>
289 lines
8.0 KiB
C
289 lines
8.0 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 BTRFS_ROOT_TRANS_TAG 0
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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->generation++;
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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->fs_info->generation;
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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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u64 running_trans_id;
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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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running_trans_id = root->fs_info->running_transaction->transid;
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if (root != root->fs_info->tree_root && root->last_trans <
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running_trans_id) {
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radix_tree_tag_set(&root->fs_info->fs_roots_radix,
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(unsigned long)root->root_key.objectid,
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BTRFS_ROOT_TRANS_TAG);
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root->commit_root = root->node;
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get_bh(root->node);
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}
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root->last_trans = running_trans_id;
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h->transid = running_trans_id;
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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->btree_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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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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struct dirty_root {
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struct list_head list;
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struct btrfs_key snap_key;
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struct buffer_head *commit_root;
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struct btrfs_root *root;
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};
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int add_dirty_roots(struct btrfs_trans_handle *trans,
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struct radix_tree_root *radix, struct list_head *list)
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{
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struct dirty_root *dirty;
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struct btrfs_root *gang[8];
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struct btrfs_root *root;
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int i;
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int ret;
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int err;
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while(1) {
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ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
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ARRAY_SIZE(gang),
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BTRFS_ROOT_TRANS_TAG);
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if (ret == 0)
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break;
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for (i = 0; i < ret; i++) {
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root = gang[i];
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radix_tree_tag_clear(radix,
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(unsigned long)root->root_key.objectid,
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BTRFS_ROOT_TRANS_TAG);
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if (root->commit_root == root->node) {
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WARN_ON(root->node->b_blocknr !=
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btrfs_root_blocknr(&root->root_item));
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brelse(root->commit_root);
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root->commit_root = NULL;
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continue;
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}
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dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
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BUG_ON(!dirty);
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memcpy(&dirty->snap_key, &root->root_key,
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sizeof(root->root_key));
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dirty->commit_root = root->commit_root;
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root->commit_root = NULL;
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dirty->root = root;
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root->root_key.offset = root->fs_info->generation;
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btrfs_set_root_blocknr(&root->root_item,
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root->node->b_blocknr);
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err = btrfs_insert_root(trans, root->fs_info->tree_root,
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&root->root_key,
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&root->root_item);
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BUG_ON(err);
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list_add(&dirty->list, list);
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}
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}
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return 0;
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}
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int drop_dirty_roots(struct btrfs_root *tree_root, struct list_head *list)
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{
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struct dirty_root *dirty;
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struct btrfs_trans_handle *trans;
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int ret;
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while(!list_empty(list)) {
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dirty = list_entry(list->next, struct dirty_root, list);
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list_del_init(&dirty->list);
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trans = btrfs_start_transaction(tree_root, 1);
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ret = btrfs_drop_snapshot(trans, dirty->root,
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dirty->commit_root);
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BUG_ON(ret);
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ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
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BUG_ON(ret);
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ret = btrfs_end_transaction(trans, tree_root);
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BUG_ON(ret);
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kfree(dirty);
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}
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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 btrfs_transaction *cur_trans;
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struct list_head dirty_fs_roots;
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DEFINE_WAIT(wait);
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INIT_LIST_HEAD(&dirty_fs_roots);
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mutex_lock(&root->fs_info->trans_mutex);
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if (trans->transaction->in_commit) {
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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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add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
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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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btrfs_set_super_generation(root->fs_info->disk_super,
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root->fs_info->generation + 1);
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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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drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
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return ret;
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}
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