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From:   Chao Yu <yuchao0@huawei.com>
To:     <jaegeuk@kernel.org>
CC:     <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, <chao@kernel.org>,
        Chao Yu <yuchao0@huawei.com>
Subject: [PATCH] f2fs: compress: fix to disallow enabling compress on non-empty file
Date:   Fri, 18 Sep 2020 11:03:49 +0800
Message-ID: <20200918030349.19667-1-yuchao0@huawei.com>
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Precedence: bulk

Compressed inode and normal inode has different layout, so we should
disallow enabling compress on non-empty file to avoid race condition
during inode .i_addr array parsing and updating.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/file.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 58e464cc15f0..139fdfc1dc55 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1821,6 +1821,8 @@ static int f2fs_setflags_common(struct inode *inode, u32 iflags, u32 mask)
 		if (iflags & F2FS_COMPR_FL) {
 			if (!f2fs_may_compress(inode))
 				return -EINVAL;
+			if (inode->i_size)
+				return -EINVAL;
 
 			set_compress_context(inode);
 		}
-- 
2.26.2