> -----Original Message----- > From: Chao Yu <[email protected]> > Sent: Monday, March 7, 2022 9:43 AM > To: Fengnan Chang <[email protected]>; [email protected] > Cc: [email protected]; 常凤楠 > <[email protected]> > Subject: Re: [RFC PATCH] f2fs: fix compress file start atomic write may cause > data corruption > > On 2022/3/5 12:00, Fengnan Chang wrote: > > When compressed file has blocks, start atomic write will be failed, > > but > > You mean f2fs_ioc_start_atomic_write will succeed, but compressed flag will > be remained in inode?
Yes. > > > still set FI_ATOMIC_FILE flag, if write partial cluster and commit > > atomic write will cause data corruption. > > Could you please explain more about why data will be corrupted? 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 no-compressed, page 1 and 2 will be compressed data or zero. And before f2fs: compress: remove unneeded read when rewrite whole cluster), even Step 2 is not right, but whole cluster will mark dirty in write_begin, and whole cluster will be re-write as no-compressed cluster, so it's ok. > > Thanks, > > > Fixes: 4c8ff7095bef (f2fs: support data compression) > > Fixes: 7eab7a696827 (f2fs: compress: remove unneeded read when rewrite > > whole cluster) > > > > Signed-off-by: Fengnan Chang <[email protected]> > > --- > > fs/f2fs/data.c | 4 +--- > > fs/f2fs/file.c | 3 ++- > > 2 files changed, 3 insertions(+), 4 deletions(-) > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index > > 6b5f389ba998..5cbee4ed0982 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -3358,8 +3358,7 @@ static int f2fs_write_begin(struct file *file, struct > address_space *mapping, > > int ret; > > > > *fsdata = NULL; > > - > > - if (len == PAGE_SIZE) > > + if (len == PAGE_SIZE && !(f2fs_is_atomic_file(inode))) > > goto repeat; > > > > ret = f2fs_prepare_compress_overwrite(inode, pagep, diff --git > > a/fs/f2fs/file.c b/fs/f2fs/file.c index cfdc41f87f5d..26a648ef9e1f > > 100644 > > --- a/fs/f2fs/file.c > > +++ b/fs/f2fs/file.c > > @@ -2009,7 +2009,8 @@ static int f2fs_ioc_start_atomic_write(struct > > file *filp) > > > > inode_lock(inode); > > > > - f2fs_disable_compressed_file(inode); > > + if (!f2fs_disable_compressed_file(inode)) > > + return -EINVAL; > > > > if (f2fs_is_atomic_file(inode)) { > > if (is_inode_flag_set(inode, FI_ATOMIC_REVOKE_REQUEST)) _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
