On Thu, Apr 9, 2020 at 10:29 AM Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> wrote: > > Stacked filesystems like overlayfs has no own writeback, but they have to > forward syncfs() requests to backend for keeping data integrity. > > During global sync() each overlayfs instance calls method ->sync_fs() > for backend although it itself is in global list of superblocks too. > As a result one syscall sync() could write one superblock several times > and send multiple disk barriers. > > This patch adds flag SB_I_SKIP_SYNC into sb->sb_iflags to avoid that. > > Reported-by: Dmitry Monakhov <dmtrmonakhov@xxxxxxxxxxxxxx> > Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx> Thanks, applied. Miklos
