On Tue, Jan 08, 2019 at 03:47:13PM +0800, Qu Wenruo wrote: > On 2019/1/8 下午3:30, Nikolay Borisov wrote: > > On 7.01.19 г. 21:10 ч., David Sterba wrote: > >> On Tue, Dec 18, 2018 at 03:10:02PM +0200, Nikolay Borisov wrote: > >>> We can never have extents marked as EXTENT_MAP_DELALLOC since this > >>> value is only ever used by btrfs_get_extent_fiemap. In this case the > >>> extent map is created by btrfs_get_extent_fiemap and is never really > >>> published, this flag is used to return the corresponding userspace one. > >>> Considering this, it's pointless having a check for EXTENT_MAP_DELALLOC > >>> in mergable_maps. Just remove it. > >> > >> An assert would be good and a comment at EXTENT_MAP_DELALLOC definition > >> repeating what's in the changelog. Otherwise ok. > > > > Do we really need the assert though, it's plainly obvious > > EXTENT_MAP_DELALLOC is only set in a single function? > > IMHO ASSERT() is not for now, but for the future. > Later on maybe some modification would change when and who sets DELALLOC > bit. Agreed, that's exactly the point. We want to catch when DELALLOC is accidentally found during normal extent merging.
