On Mon, Nov 22, 2021 at 5:01 AM Chengguang Xu <cgxu519@xxxxxxxxxxxx> wrote: > > From: Chengguang Xu <charliecgxu@xxxxxxxxxxx> > > Now overlayfs can only sync own dirty inodes during syncfs, > so remove unnecessary sync_filesystem() on upper file system. > > Signed-off-by: Chengguang Xu <charliecgxu@xxxxxxxxxxx> > --- > fs/overlayfs/super.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index ccffcd96491d..213b795a6a86 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -292,18 +292,14 @@ static int ovl_sync_fs(struct super_block *sb, int wait) > /* > * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). > * All the super blocks will be iterated, including upper_sb. > - * > - * If this is a syncfs(2) call, then we do need to call > - * sync_filesystem() on upper_sb, but enough if we do it when being > - * called with wait == 1. > */ > - if (!wait) > - return 0; > - > upper_sb = ovl_upper_mnt(ofs)->mnt_sb; > - > down_read(&upper_sb->s_umount); > - ret = sync_filesystem(upper_sb); > + if (wait) > + wait_sb_inodes(upper_sb); > + if (upper_sb->s_op->sync_fs) > + upper_sb->s_op->sync_fs(upper_sb, wait); > + ret = ovl_sync_upper_blockdev(upper_sb, wait); I think it will be cleaner to use a helper ovl_sync_upper_filesystem() with everything from upper_sb = ... and a comment to explain that this is a variant of __sync_filesystem() where all the dirty inodes write have already been started. Thanks, Amir. P.S. I like this "stoopid proof" v6 because I can understand it ;-)
