[PATCH] libf2fs: Fix calculation of usable segments for single zoned
From: Yonggil Song
Date: Mon Oct 07 2024 - 01:21:40 EST
There was a bug that did not subtract the super block area when calculating
the usable segments for a single zoned device with a conventional zone.
This bug resulted in incorrect the overprovision and reserved area.
<256MiB legacy block + zoned block w/ 32MiB zone size>
Info: Overprovision ratio = 3.570%
Info: Overprovision segments = 656 (GC reserved = 560)
<8 conventional zone + 1016 sequential zone w/ 32MiB zone size>
Info: Overprovision ratio = 3.700%
Info: Overprovision segments = 676 (GC reserved = 578)
This patch fixes the bug by subtracting the super block area when there is
only one zoned device.
Signed-off-by: Yonggil Song <yonggil.song@xxxxxxxxxxx>
---
lib/libf2fs_zoned.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/lib/libf2fs_zoned.c b/lib/libf2fs_zoned.c
index 89ba5ad73a76..cc5c064b7e3e 100644
--- a/lib/libf2fs_zoned.c
+++ b/lib/libf2fs_zoned.c
@@ -555,6 +555,11 @@ uint32_t f2fs_get_usable_segments(struct f2fs_super_block *sb)
}
usable_segs -= (get_sb(main_blkaddr) - get_sb(segment0_blkaddr)) >>
get_sb(log_blocks_per_seg);
+
+ /* single zoned device needs to remove a super block area */
+ if (c.ndevs == 1)
+ usable_segs -= (get_sb(segment0_blkaddr) >> get_sb(log_blocks_per_seg));
+
return usable_segs;
#endif
return get_sb(segment_count_main);
--
2.43.0