Re: [PATCH v6 0/2] btrfs: Don't block system suspend during fstrim

[David Sterba <dsterba@suse.cz>]

On Tue, Sep 17, 2024 at 10:33:03PM +0200, Luca Stefani wrote:
> Changes since v5:
> * Make chunk size a define
> * Remove superfluous trim_interrupted checks
>   after moving them to trim_no_bitmap/trim_bitmaps
> 
> Changes since v4:
> * Set chunk size to 1G
> * Set proper error return codes in case of interruption
> * Dropped fstrim_range fixup as pulled in -next
> 
> Changes since v3:
> * Went back to manual chunk size
> 
> Changes since v2:
> * Use blk_alloc_discard_bio directly
> * Reset ret to ERESTARTSYS
> 
> Changes since v1:
> * Use bio_discard_limit to calculate chunk size
> * Makes use of the split chunks
> 
> Original discussion: https://lore.kernel.org/lkml/20240822164908.4957-1-luca.stefani.ge1@gmail.com/
> v1: https://lore.kernel.org/lkml/20240902114303.922472-1-luca.stefani.ge1@gmail.com/
> v2: https://lore.kernel.org/lkml/20240902205828.943155-1-luca.stefani.ge1@gmail.com/
> v3: https://lore.kernel.org/lkml/20240903071625.957275-4-luca.stefani.ge1@gmail.com/
> v4: https://lore.kernel.org/lkml/20240916101615.116164-1-luca.stefani.ge1@gmail.com/
> v5: https://lore.kernel.org/lkml/20240916125707.127118-1-luca.stefani.ge1@gmail.com/
> 
> ---
> 
> NB: I didn't change btrfs_discard_workfn yet to add error checks
> as I don't know what semantics we should have in that case.
> The work queue is always re-scheduled and created with WQ_FREEZABLE
> so it should be automatically frozen. Shall I simply add some logs?

About that, this may be a bit tricky, interrupting trim there is handled
but the accounting may get wrong. This is related but a different
problem than the suspend vs trim.