lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Btrfs: add sequence numbers to delayed refs

Browse Source 
Sequence numbers are needed to reconstruct the backrefs of a given extent to
a certain point in time. The total set of backrefs consist of the set of
backrefs recorded on disk plus the enqueued delayed refs for it that existed
at that moment.

This patch also adds a list that records all delayed refs which are
currently in the process of being added.

When walking all refs of an extent in btrfs_find_all_roots(), we freeze the
current state of delayed refs, honor anythinh up to this point and prevent
processing newer delayed refs to assert consistency.

Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
This commit is contained in:
Arne Jansen
2011-09-14 12:37:00 +02:00
committed by Jan Schmidt
parent 5b25f70f42
commit 00f04b8879
3 changed files with 108 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
fs/btrfs/transaction.c
View File

@ -36,6 +36,8 @@ static noinline void put_transaction(struct btrfs_transaction *transaction)
WARN_ON(atomic_read(&transaction->use_count) == 0);
if (atomic_dec_and_test(&transaction->use_count)) {
BUG_ON(!list_empty(&transaction->list));
WARN_ON(transaction->delayed_refs.root.rb_node);
WARN_ON(!list_empty(&transaction->delayed_refs.seq_head));
memset(transaction, 0, sizeof(*transaction));
kmem_cache_free(btrfs_transaction_cachep, transaction);
}
@ -108,8 +110,10 @@ loop:
cur_trans->delayed_refs.num_heads = 0;
cur_trans->delayed_refs.flushing = 0;
cur_trans->delayed_refs.run_delayed_start = 0;
cur_trans->delayed_refs.seq = 1;
spin_lock_init(&cur_trans->commit_lock);
spin_lock_init(&cur_trans->delayed_refs.lock);
INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head);
INIT_LIST_HEAD(&cur_trans->pending_snapshots);
list_add_tail(&cur_trans->list, &root->fs_info->trans_list);