The patch below does not apply to the 4.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 17024ad0a0fdfcfe53043afb969b813d3e020c21 Mon Sep 17 00:00:00 2001 From: Omar Sandoval <osandov@xxxxxx> Date: Thu, 20 Jul 2017 15:10:35 -0700 Subject: [PATCH] Btrfs: fix early ENOSPC due to delalloc If a lot of metadata is reserved for outstanding delayed allocations, we rely on shrink_delalloc() to reclaim metadata space in order to fulfill reservation tickets. However, shrink_delalloc() has a shortcut where if it determines that space can be overcommitted, it will stop early. This made sense before the ticketed enospc system, but now it means that shrink_delalloc() will often not reclaim enough space to fulfill any tickets, leading to an early ENOSPC. (Reservation tickets don't care about being able to overcommit, they need every byte accounted for.) Fix it by getting rid of the shortcut so that shrink_delalloc() reclaims all of the metadata it is supposed to. This fixes early ENOSPCs we were seeing when doing a btrfs receive to populate a new filesystem, as well as early ENOSPCs Christoph saw when doing a big cp -r onto Btrfs. Fixes: 957780eb2788 ("Btrfs: introduce ticketed enospc infrastructure") Tested-by: Christoph Anton Mitterer <mail@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Josef Bacik <jbacik@xxxxxx> Signed-off-by: Omar Sandoval <osandov@xxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index a6635f07b8f1..e3b0b4196d3d 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4825,10 +4825,6 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim, else flush = BTRFS_RESERVE_NO_FLUSH; spin_lock(&space_info->lock); - if (can_overcommit(fs_info, space_info, orig, flush, false)) { - spin_unlock(&space_info->lock); - break; - } if (list_empty(&space_info->tickets) && list_empty(&space_info->priority_tickets)) { spin_unlock(&space_info->lock);