On 07/29, Chao Yu wrote: > Ping, Added. Thanks.
> > On 2021/7/20 9:19, Chao Yu wrote: > > On 2021/7/20 9:15, Jaegeuk Kim wrote: > > > Wasn't it supposed to be v1? > > > > I skip IPU case for v1, and resend it as v3, is it fine to you? > > > > Thanks, > > > > > > > > On 07/20, Chao Yu wrote: > > > > [1] > > > > https://www.mail-archive.com/[email protected]/msg15126.html > > > > > > > > As [1] reported, if lower device doesn't support write barrier, in below > > > > case: > > > > > > > > - write page #0; persist > > > > - overwrite page #0 > > > > - fsync > > > > - write data page #0 OPU into device's cache > > > > - write inode page into device's cache > > > > - issue flush > > > > > > > > If SPO is triggered during flush command, inode page can be persisted > > > > before data page #0, so that after recovery, inode page can be recovered > > > > with new physical block address of data page #0, however there may > > > > contains dummy data in new physical block address. > > > > > > > > Then what user will see is: after overwrite & fsync + SPO, old data in > > > > file was corrupted, if any user do care about such case, we can suggest > > > > user to use STRICT fsync mode, in this mode, we will force to use atomic > > > > write sematics to keep write order in between data/node and last node, > > > > so that it avoids potential data corruption during fsync(). > > > > > > > > Signed-off-by: Chao Yu <[email protected]> > > > > --- > > > > fs/f2fs/file.c | 12 ++++++++++++ > > > > 1 file changed, 12 insertions(+) > > > > > > > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > > > > index 6afd4562335f..00b45876eaa1 100644 > > > > --- a/fs/f2fs/file.c > > > > +++ b/fs/f2fs/file.c > > > > @@ -301,6 +301,18 @@ static int f2fs_do_sync_file(struct file *file, > > > > loff_t start, loff_t end, > > > > f2fs_exist_written_data(sbi, ino, > > > > UPDATE_INO)) > > > > goto flush_out; > > > > goto out; > > > > + } else { > > > > + /* > > > > + * for OPU case, during fsync(), node can be persisted > > > > before > > > > + * data when lower device doesn't support write > > > > barrier, result > > > > + * in data corruption after SPO. > > > > + * So for strict fsync mode, force to use atomic write > > > > sematics > > > > + * to keep write order in between data/node and last > > > > node to > > > > + * avoid potential data corruption. > > > > + */ > > > > + if (F2FS_OPTION(sbi).fsync_mode == > > > > + FSYNC_MODE_STRICT && !atomic) > > > > + atomic = true; > > > > } > > > > go_write: > > > > /* > > > > -- > > > > 2.22.1 > > > > > > _______________________________________________ > > Linux-f2fs-devel mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
