[PATCH v2 15/15] Btrfs: tree mod log sanity checks in join_transaction
From: Jan Schmidt <hidden>
Date: 2012-05-26 10:59:52
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
When a fresh transaction begins, the tree mod log must be clean. Users of the tree modification log must ensure they never span across transaction boundaries. We reset the sequence to 0 in this safe situation to make absolutely sure overflow can't happen. Signed-off-by: Jan Schmidt <redacted> --- fs/btrfs/transaction.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index eb2bd82..3f50cba 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c@@ -122,6 +122,15 @@ loop: cur_trans->delayed_refs.flushing = 0; cur_trans->delayed_refs.run_delayed_start = 0; cur_trans->delayed_refs.seq = 1; + + /* + * although the tree mod log is per file system and not per transaction, + * the log must never go across transaction boundaries. + */ + BUG_ON(!list_empty(&fs_info->tree_mod_seq_list)); + BUG_ON(!RB_EMPTY_ROOT(&fs_info->tree_mod_log)); + atomic_set(&fs_info->tree_mod_seq, 0); + init_waitqueue_head(&cur_trans->delayed_refs.seq_wait); spin_lock_init(&cur_trans->commit_lock); spin_lock_init(&cur_trans->delayed_refs.lock);
--
1.7.3.4