On Thu, Jan 08, 2015 at 02:33:17PM -0600, Eric Sandeen wrote:
> On 1/8/15 2:18 PM, Jaegeuk Kim wrote:
> > On Thu, Jan 08, 2015 at 01:54:20PM -0600, Eric Sandeen wrote:
> >> On 1/8/15 12:10 PM, Jaegeuk Kim wrote:
> >>> This patch add an ioctl to shutdown f2fs, which stops all the further
> >>> block
> >>> writes after this point.
> >>
> >> would it make sense to just re-use the xfs ioctl nr, if the semantics are
> >> the same?
> >
> > The semantics are not same for now.
> > In order to reuse xfs ioctl, it needs to support options for flushing logs.
>
> the xfs iotl has 3 behaviors optional:
>
> #define XFS_FSOP_GOING_FLAGS_DEFAULT 0x0 /* going down */
> #define XFS_FSOP_GOING_FLAGS_LOGFLUSH 0x1 /* flush log but not
> data */
> #define XFS_FSOP_GOING_FLAGS_NOLOGFLUSH 0x2 /* don't flush log
> nor data */
>
> if f2fs currently supports a subset, you could just -EOPNOTSUPP on the others.
No, just do a default shutdown operation if the semantics cannot be
supported.
- XFS_FSOP_GOING_FLAGS_DEFAULT ==
consistent on disk before shutdown
+ implemented by freeze/thaw/shutdown sequence
- XFS_FSOP_GOING_FLAGS_LOGFLUSH ==
consistent journal on disk before shutdown
+ implemented by journal flush/shutdown sequence
- XFS_FSOP_GOING_FLAGS_NOLOGFLUSH ==
nothing consistent on disk before shutdown
+ just a shutdown call.
f2fs can at least support XFS_FSOP_GOING_FLAGS_DEFAULT and
XFS_FSOP_GOING_FLAGS_NOLOGFLUSH....
> If the semantics are completely different, maybe it shouldn't share the
> name at all. ;)
The semantics are quite clear and generic - when you look at what
they actually mean rather than looking at the implementation.
There's no need for new ioctls here.
Cheers,
Dave.
--
Dave Chinner
da...@fromorbit.com
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