cated space we have. Then if we fail to make a reservation within our allocated space, check to see if we can overcommit. In the normal flushing case (like with delalloc metadata reservations) we'll take the free space and divide it by 2 if our metadata profile is setup for DUP or any of those, and then divide it by 8 to make sure we don't overcommit too much. Then if we're in a non-flushing case (we really need this reservation now!) we only limit ourselves to half of the free space. This makes this fio test [torrent] filename=torrent-test rw=randwrite size=4g ioengine=sync directory=/mnt/btrfs-test go from taking around 45 minutes to 10 seconds on my freshly formatted 3 TiB file system. This doesn't seem to break my other enospc tests, but could really use some more testing as this is a super scary change. Thanks, Signed-off-by: Josef Bacik