On 2020/5/12 上午2:58, David Sterba wrote: > On Tue, May 05, 2020 at 08:02:19AM +0800, Qu Wenruo wrote: >> This patchset can be fetched from github: >> https://github.com/adam900710/btrfs-progs/tree/skinny_bg_tree >> Which is based on v5.6 tag, with extra cleanups (sent to mail list) applied. >> >> This patchset provides the needed user space infrastructure for SKINNY_BG_TREE >> feature. >> >> Since it's an new incompatible feature, unlike SKINNY_METADATA, btrfs-progs >> is needed to convert existing fs (unmounted) to new format, and >> vice-verse. >> >> Now btrfstune can convert regular extent tree fs to bg tree fs to >> improve mount time. >> >> For the performance improvement, please check the kernel patchset cover >> letter or the last patch. >> (SPOILER ALERT: It's super fast) >> >> Changelog: >> v2: >> - Rebase to v5.2.2 tag >> - Add btrfstune ability to convert existing fs to BG_TREE feature >> >> v3: >> - Fix a bug that temp chunks are not cleaned up properly >> This is caused by wrong timing btrfs_convert_to_bg_tree() is called. >> It should be called after temp chunks cleaned up. >> >> - Fix a bug that an extent buffer get leaked >> This is caused by newly created bg tree not added to dirty list. >> >> v4: >> - Go with skinny bg tree other than regular block group item >> We're introducing a new incompatible feature anyway, why not go >> extreme? >> >> - Use the same refactor as kernel. >> To make code much cleaner and easier to read. >> >> - Add the ability to rollback to regular extent tree. >> So confident tester can try SKINNY_BG_TREE using their real world >> data, and rollback if they still want to mount it using older kernels. >> >> Qu Wenruo (11): >> btrfs-progs: check/lowmem: Lookup block group item in a seperate >> function >> btrfs-progs: block-group: Refactor how we read one block group item >> btrfs-progs: Rename btrfs_remove_block_group() and >> free_block_group_item() >> btrfs-progs: block-group: Refactor how we insert a block group item >> btrfs-progs: block-group: Rename write_one_cahce_group() > > I'll add the above patches independently, for the rest I don't know. I > still think the separate tree is somehow wrong so have to convince > myself that it's not. No problem. Since the refactor would be the basis for whatever the final method we choose, it should be pretty OK. Even if we go something like (0, NEW_BLOCK_GROUP_ITEM, bytenr) in extent tree, the refactor still makes a lot of sense. BTW, if we merge the skip_bg mount option before this patchset, we could even make the skinny_bg_tree feature RO compactable. So it would be a good time reviewing that feature. Thanks, Qu
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