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authorChris Mason <chris.mason@oracle.com>2009-04-24 14:39:25 -0400
committerChris Mason <chris.mason@oracle.com>2009-04-24 15:46:05 -0400
commit59bc5c758ece00fb0b2a170dd8fbbf31f1856c8a (patch)
tree746fcdfe8181c638b593174deb4d841310e8c698 /fs/btrfs/transaction.c
parente980b50cda1610f1c17978d9b7fd311a9dd93877 (diff)
Btrfs: fix deadlocks and stalls on dead root removal
After a transaction commit, the old root of the subvol btrees are sent through snapshot removal. This is what actually frees up any blocks replaced by COW, and anything the old blocks pointed to. Snapshot deletion will pause when a transaction commit has started, which helps to avoid a huge amount of delayed reference count updates piling up as the transaction is trying to close. But, this pause happens after the snapshot deletion process has asked other procs on the system to throttle back a bit so that it can make progress. We don't want to throttle everyone while we're waiting for the transaction commit, it leads to deadlocks in the user transaction ioctls used by Ceph and makes things slower in general. This patch changes things to avoid the throttling while we sleep. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/transaction.c')
-rw-r--r--fs/btrfs/transaction.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 2869b3361eb6..01b143605ec1 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -687,7 +687,13 @@ static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
687 prepare_to_wait(&info->transaction_wait, &wait, 687 prepare_to_wait(&info->transaction_wait, &wait,
688 TASK_UNINTERRUPTIBLE); 688 TASK_UNINTERRUPTIBLE);
689 mutex_unlock(&info->trans_mutex); 689 mutex_unlock(&info->trans_mutex);
690
691 atomic_dec(&info->throttles);
692 wake_up(&info->transaction_throttle);
693
690 schedule(); 694 schedule();
695
696 atomic_inc(&info->throttles);
691 mutex_lock(&info->trans_mutex); 697 mutex_lock(&info->trans_mutex);
692 finish_wait(&info->transaction_wait, &wait); 698 finish_wait(&info->transaction_wait, &wait);
693 } 699 }