From ff7c1d33551862c86f7737fe88edc3e499d291e6 Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Mon, 26 Nov 2012 08:41:29 +0000 Subject: [PATCH] Btrfs: don't start a new transaction when starting sync If there is no running transaction in the fs, we needn't start a new one when we want to start sync. Signed-off-by: Miao Xie Signed-off-by: Chris Mason --- fs/btrfs/ioctl.c | 14 ++++++++++---- fs/btrfs/transaction.c | 13 ++++++++----- 2 files changed, 18 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 5022e62e63a8..7b1f614f51f6 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3065,16 +3065,22 @@ static noinline long btrfs_ioctl_start_sync(struct btrfs_root *root, u64 transid; int ret; - trans = btrfs_start_transaction(root, 0); - if (IS_ERR(trans)) - return PTR_ERR(trans); + trans = btrfs_attach_transaction(root); + if (IS_ERR(trans)) { + if (PTR_ERR(trans) != -ENOENT) + return PTR_ERR(trans); + + /* No running transaction, don't bother */ + transid = root->fs_info->last_trans_committed; + goto out; + } transid = trans->transid; ret = btrfs_commit_transaction_async(trans, root, 0); if (ret) { btrfs_end_transaction(trans, root); return ret; } - +out: if (argp) if (copy_to_user(argp, &transid, sizeof(transid))) return -EFAULT; diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index bcc6b65be3b0..8db401fa2f8f 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1307,9 +1307,10 @@ static void do_async_commit(struct work_struct *work) * We've got freeze protection passed with the transaction. * Tell lockdep about it. */ - rwsem_acquire_read( - &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], - 0, 1, _THIS_IP_); + if (ac->newtrans->type < TRANS_JOIN_NOLOCK) + rwsem_acquire_read( + &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], + 0, 1, _THIS_IP_); current->journal_info = ac->newtrans; @@ -1347,8 +1348,10 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans, * Tell lockdep we've released the freeze rwsem, since the * async commit thread will be the one to unlock it. */ - rwsem_release(&root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], - 1, _THIS_IP_); + if (trans->type < TRANS_JOIN_NOLOCK) + rwsem_release( + &root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1], + 1, _THIS_IP_); schedule_delayed_work(&ac->work, 0); -- 2.20.1