From 9b56adcf525522e9ffa52471260298d91fc1d395 Mon Sep 17 00:00:00 2001 From: Fengnan Chang Date: Fri, 18 Mar 2022 09:23:04 +0800 Subject: f2fs: fix compressed file start atomic write may cause data corruption When compressed file has blocks, f2fs_ioc_start_atomic_write will succeed, but compressed flag will be remained in inode. If write partial compreseed cluster and commit atomic write will cause data corruption. This is the reproduction process: Step 1: create a compressed file ,write 64K data , call fsync(), then the blocks are write as compressed cluster. Step2: iotcl(F2FS_IOC_START_ATOMIC_WRITE) --- this should be fail, but not. write page 0 and page 3. iotcl(F2FS_IOC_COMMIT_ATOMIC_WRITE) -- page 0 and 3 write as normal file, Step3: drop cache. read page 0-4 -- Since page 0 has a valid block address, read as non-compressed cluster, page 1 and 2 will be filled with compressed data or zero. The root cause is, after commit 7eab7a696827 ("f2fs: compress: remove unneeded read when rewrite whole cluster"), in step 2, f2fs_write_begin() only set target page dirty, and in f2fs_commit_inmem_pages(), we will write partial raw pages into compressed cluster, result in corrupting compressed cluster layout. Fixes: 4c8ff7095bef ("f2fs: support data compression") Fixes: 7eab7a696827 ("f2fs: compress: remove unneeded read when rewrite whole cluster") Reported-by: kernel test robot Reported-by: Dan Carpenter Signed-off-by: Fengnan Chang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/f2fs/data.c') diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index b09f401f8960..5675af1b6916 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -3363,7 +3363,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping, *fsdata = NULL; - if (len == PAGE_SIZE) + if (len == PAGE_SIZE && !(f2fs_is_atomic_file(inode))) goto repeat; ret = f2fs_prepare_compress_overwrite(inode, pagep, -- cgit v1.2.3