What are the implications of not clearing v1 before enabling v2?
>From btrfs insp dump-t, I still see the v1 bitmaps present:
root tree
leaf 6468501504 items 42 free space 9246 generation 22 owner ROOT_TREE
leaf 6468501504 flags 0x1(WRITTEN) backref revision 1
...
item 30 key (FREE_SPACE UNTYPED 22020096) itemoff 11145 itemsize 41
location key (256 INODE_ITEM 0)
cache generation 17 entries 0 bitmaps 0
item 31 key (FREE_SPACE UNTYPED 1095761920) itemoff 11104 itemsize 41
location key (257 INODE_ITEM 0)
cache generation 17 entries 0 bitmaps 0
...
And later the free space tree:
free space tree key (FREE_SPACE_TREE ROOT_ITEM 0)
leaf 6471073792 items 39 free space 15196 generation 22 owner FREE_SPACE_TREE
leaf 6471073792 flags 0x1(WRITTEN) backref revision 1
fs uuid 3c464210-08c7-4cf0-b175-e4b781ebea19
chunk uuid f1d18732-7c3d-401c-8637-e7d4d9c7a0b8
item 0 key (1048576 FREE_SPACE_INFO 4194304) itemoff 16275 itemsize 8
free space info extent count 2 flags 0
item 1 key (1048576 FREE_SPACE_EXTENT 16384) itemoff 16275 itemsize 0
free space extent
item 2 key (1081344 FREE_SPACE_EXTENT 4161536) itemoff 16275 itemsize 0
free space extent
...
I was surprised there's no warning when I use space_cache=v2 without
first clearing v1.
--
Chris Murphy
