From 9d0d47d5c3c5b53d444ecf7022bedc5553c544c0 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Tue, 21 Mar 2023 11:13:41 +0000 Subject: [PATCH] btrfs: update flush method assertion when reserving space When reserving space, at space-info.c:__reserve_bytes(), we assert that either the current task is not holding a transacion handle, or, if it is, that the flush method is not BTRFS_RESERVE_FLUSH_ALL. This is because that flush method can trigger transaction commits, and therefore could lead to a deadlock. However there are other 2 flush methods that can trigger transaction commits: 1) BTRFS_RESERVE_FLUSH_ALL_STEAL 2) BTRFS_RESERVE_FLUSH_EVICT So update the assertion to check the flush method is also not one those two methods if the current task is holding a transaction handle. Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/space-info.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 3eecce8..379a0e7 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -1603,7 +1603,18 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info, bool pending_tickets; ASSERT(orig_bytes); - ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL); + /* + * If have a transaction handle (current->journal_info != NULL), then + * the flush method can not be neither BTRFS_RESERVE_FLUSH_ALL* nor + * BTRFS_RESERVE_FLUSH_EVICT, as we could deadlock because those + * flushing methods can trigger transaction commits. + */ + if (current->journal_info) { + /* One assert per line for easier debugging. */ + ASSERT(flush != BTRFS_RESERVE_FLUSH_ALL); + ASSERT(flush != BTRFS_RESERVE_FLUSH_ALL_STEAL); + ASSERT(flush != BTRFS_RESERVE_FLUSH_EVICT); + } if (flush == BTRFS_RESERVE_FLUSH_DATA) async_work = &fs_info->async_data_reclaim_work; -- 2.7.4