Re: [f2fs-dev] [PATCH v2] f2fs: accurately adjust free_sections during free_segment_range

[Chao Yu <chao@kernel.org>]

On 8/25/26 09:53, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@google.com>
> 
> In free_segment_range(), MAIN_SECS(sbi) is temporarily reduced by `secs`
> to restrict block allocation to the safe remaining main area while valid
> blocks in the truncated range are evacuated by GC.
> 
> However, FREE_I(sbi)->free_sections tracks the total number of free
> sections across the whole filesystem. If any sections within the
> truncated range were already free upon entering free_segment_range(),
> failing to deduct them from free_sections causes the filesystem to
> overestimate available free sections in the active, reduced main area.
> This leads to inconsistent free section accounting during GC data
> migration and can trigger unexpected allocation failures or assertion
> errors when space is tight.
> 
> Fix this by calculating the number of already-free sections in the
> truncated range, deducting them from free_sections upon entering
> free_segment_range(), and restoring them on exit.
> 
> Fixes: b4b10061ef98 ("f2fs: refactor resize_fs to avoid meta updates in progress")
> Cc: stable@vger.kernel.org
> Signed-off-by: Daeho Jeong <daehojeong@google.com>
> Signed-off-by: Sunmin Jeong <s_min.jeong@samsung.com>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,