linux-kernel - [PATCH v2] f2fs: compress: disallow disabling compress on non-empty compressed file

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Date:   Wed, 27 Oct 2021 13:16:00 +0900
From:   Hyeong-Jun Kim <hj514.kim@...sung.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <chao@...nel.org>
Cc:     Hyeong-Jun Kim <hj514.kim@...sung.com>,
        Sungjong Seo <sj1557.seo@...sung.com>,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] f2fs: compress: disallow disabling compress on non-empty
 compressed file

Compresse file and normal file has differ in i_addr addressing,
specifically addrs per inode/block. So, we will face data loss, if we
disable the compression flag on non-empty files. Therefore we should
disallow not only enabling but disabling the compression flag on
non-empty files.

---
v2:
 - check F2FS_HAS_BLOCKS() instead of i_size

Fixes: 4c8ff7095bef ("f2fs: support data compression")
Signed-off-by: Sungjong Seo <sj1557.seo@...sung.com>
Signed-off-by: Hyeong-Jun Kim <hj514.kim@...sung.com>
---
 fs/f2fs/f2fs.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index b8e8f8c716b0..23b437dc7d65 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4177,8 +4177,7 @@ static inline bool f2fs_disable_compressed_file(struct inode *inode)
 
 	if (!f2fs_compressed_file(inode))
 		return true;
-	if (S_ISREG(inode->i_mode) &&
-		(get_dirty_pages(inode) || atomic_read(&fi->i_compr_blocks)))
+	if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode))
 		return false;
 
 	fi->i_flags &= ~F2FS_COMPR_FL;
-- 
2.25.1