Messages in this thread | | | From | Miklos Szeredi <> | Date | Mon, 23 Apr 2018 15:39:45 +0200 | Subject | Re: [RFC PATCH 13/35] ovl: readd fsync |
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On Mon, Apr 23, 2018 at 3:36 PM, Vivek Goyal <vgoyal@redhat.com> wrote: > On Thu, Apr 12, 2018 at 05:08:04PM +0200, Miklos Szeredi wrote: >> Implement stacked fsync(). >> >> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> >> --- >> fs/overlayfs/file.c | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c >> index b98204c1c19c..4417527667ff 100644 >> --- a/fs/overlayfs/file.c >> +++ b/fs/overlayfs/file.c >> @@ -222,10 +222,30 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) >> return ret; >> } >> >> +static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync) >> +{ >> + struct fd real; >> + const struct cred *old_cred; >> + int ret; >> + >> + ret = ovl_real_file(file, &real); >> + if (ret) >> + return ret; >> + >> + old_cred = ovl_override_creds(file_inode(file)->i_sb); >> + ret = vfs_fsync_range(real.file, start, end, datasync); >> + revert_creds(old_cred); > > Can we avoid calling fsync() on real file if it is not upper. Is it worth > optimizing.
Not sure it's worth bothering with. If caller of fsync(2) didn't worry about cost, then why should we?
Thanks, Miklos
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