On Fri, Jan 07, 2022 at 05:52:48PM -0800, Jaegeuk Kim wrote: > On 01/07, Eric Biggers wrote: > > Hi Jaegeuk, > > > > On Tue, Jan 04, 2022 at 01:24:16PM -0800, Jaegeuk Kim wrote: > > > DIO preallocates physical blocks before writing data, but if an error > > > occurrs > > > or power-cut happens, we can see block contents from the disk. This patch > > > tries > > > to fix it by 1) turning to buffered writes for DIO into holes, 2) > > > truncating > > > unwritten blocks from error or power-cut. > > > > > > Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org> > > > --- > > > fs/f2fs/data.c | 5 ++++- > > > fs/f2fs/f2fs.h | 5 +++++ > > > fs/f2fs/file.c | 27 ++++++++++++++++++--------- > > > fs/f2fs/inode.c | 8 ++++++++ > > > 4 files changed, 35 insertions(+), 10 deletions(-) > > > > Unfortunately, this patch doesn't completely fix the uninitialized data > > exposure. The problem is that it only makes DIO writes fall back to > > buffered > > writes for holes, and not for reserved blocks (NEW_ADDR). f2fs's reserved > > blocks are *not* the same as the unwritten extents that other filesystems > > have; > > f2fs's reserved blocks have to be turned into regular blocks before DIO can > > write to them. That immediately exposes them to concurrent reads (at least > > buffered reads, but I think DIO reads too). > > Isn't it resolved by i_size which gives the written blocks only? >
I'm not sure what you mean, but this is for non-extending writes, so i_size isn't relevant. - Eric _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
