Re: [PATCH] f2fs: compress: remove unneed check condition

From: Chao Yu
Date: Thu Apr 22 2021 - 02:51:22 EST


On 2021/4/22 12:04, Jaegeuk Kim wrote:
On 04/21, Chao Yu wrote:
In only call path of __cluster_may_compress(), __f2fs_write_data_pages()
has checked SBI_POR_DOING condition, and also cluster_may_compress()
has checked CP_ERROR_FLAG condition, so remove redundant check condition
in __cluster_may_compress() for cleanup.

I think cp_error can get any time without synchronization. Is it safe to say
it's redundant?

Yes,

But no matter how late we check cp_error, cp_error can happen after our
check points, it won't cause regression if we remove cp_error check there,
because for compress write, it uses OPU, it won't overwrite any existed data
in device.

Seems it will be more appropriate to check cp_error in
f2fs_write_compressed_pages() like we did in f2fs_write_single_data_page()
rather than in __cluster_may_compress().

BTW, shouldn't we rename __cluster_may_compress() to
cluster_beyond_filesize() for better readability?

Thanks,



Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
fs/f2fs/compress.c | 5 -----
1 file changed, 5 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 3c9d797dbdd6..532c311e3a89 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -906,11 +906,6 @@ static bool __cluster_may_compress(struct compress_ctx *cc)
f2fs_bug_on(sbi, !page);
- if (unlikely(f2fs_cp_error(sbi)))
- return false;
- if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
- return false;
-
/* beyond EOF */
if (page->index >= nr_pages)
return false;
--
2.29.2
.