On 15.07.2017 00:36, Omar Sandoval wrote: > On Thu, Jul 06, 2017 at 10:59:27PM -0700, Omar Sandoval wrote: >> From: Omar Sandoval <[email protected]> >> >> 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. > > Jeff, Nikolay, did either of you get a chance to test this yet?
I tested this patch with generic/273 and it didn't prevent ENOSPC there. > >> Signed-off-by: Omar Sandoval <[email protected]> >> --- >> I don't have a good reproducer for this except for the btrfs send stream >> I was given by someone internally, unfortunately. >> >> fs/btrfs/extent-tree.c | 4 ---- >> 1 file changed, 4 deletions(-) >> >> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c >> index 33d979e9ea2a..83eecd33ad96 100644 >> --- a/fs/btrfs/extent-tree.c >> +++ b/fs/btrfs/extent-tree.c >> @@ -4776,10 +4776,6 @@ static void shrink_delalloc(struct btrfs_root *root, >> u64 to_reclaim, u64 orig, >> else >> flush = BTRFS_RESERVE_NO_FLUSH; >> spin_lock(&space_info->lock); >> - if (can_overcommit(root, space_info, orig, flush)) { >> - spin_unlock(&space_info->lock); >> - break; >> - } >> if (list_empty(&space_info->tickets) && >> list_empty(&space_info->priority_tickets)) { >> spin_unlock(&space_info->lock); >> -- >> 2.13.2 >> > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
