From: Qu Wenruo Date: Mon, 1 Aug 2022 01:35:57 +0000 (+0800) Subject: btrfs: dump extra info if one free space cache has more bitmaps than it should X-Git-Tag: v6.6.17~6129^2~219 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=62cd9d4474282a1eb84f945955c56cbfc42e1ffe;p=platform%2Fkernel%2Flinux-rpi.git btrfs: dump extra info if one free space cache has more bitmaps than it should There is an internal report on hitting the following ASSERT() in recalculate_thresholds(): ASSERT(ctl->total_bitmaps <= max_bitmaps); Above @max_bitmaps is calculated using the following variables: - bytes_per_bg 8 * 4096 * 4096 (128M) for x86_64/x86. - block_group->length The length of the block group. @max_bitmaps is the rounded up value of block_group->length / 128M. Normally one free space cache should not have more bitmaps than above value, but when it happens the ASSERT() can be triggered if CONFIG_BTRFS_ASSERT is also enabled. But the ASSERT() itself won't provide enough info to know which is going wrong. Is the bg too small thus it only allows one bitmap? Or is there something else wrong? So although I haven't found extra reports or crash dump to do further investigation, add the extra info to make it more helpful to debug. Reviewed-by: Anand Jain Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 996da650..85404c6 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -693,6 +693,12 @@ static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) max_bitmaps = max_t(u64, max_bitmaps, 1); + if (ctl->total_bitmaps > max_bitmaps) + btrfs_err(block_group->fs_info, +"invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu", + block_group->start, block_group->length, + ctl->total_bitmaps, ctl->unit, max_bitmaps, + bytes_per_bg); ASSERT(ctl->total_bitmaps <= max_bitmaps); /*