On Wed, 2019-08-28 at 09:28 -0400, Brian Foster wrote:
> On Fri, Aug 23, 2019 at 09:00:22AM +0800, Ian Kent wrote:
> > Add the fs_context_operations method .free that performs fs
> > context cleanup on context release.
> >
> > Signed-off-by: Ian Kent <raven@xxxxxxxxxx>
> > ---
> > fs/xfs/xfs_super.c | 22 ++++++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> > diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> > index aae0098fecab..9976163dc537 100644
> > --- a/fs/xfs/xfs_super.c
> > +++ b/fs/xfs/xfs_super.c
> > @@ -2129,10 +2129,32 @@ static const struct super_operations
> > xfs_super_operations = {
> > .free_cached_objects = xfs_fs_free_cached_objects,
> > };
> >
> > +static void xfs_fc_free(struct fs_context *fc)
> > +{
> > + struct xfs_fs_context *ctx = fc->fs_private;
> > + struct xfs_mount *mp = fc->s_fs_info;
> > +
> > + if (mp) {
> > + /*
> > + * If an error occurs before ownership the xfs_mount
> > + * info struct is passed to xfs by the VFS (by
> > assigning
> > + * it to sb->s_fs_info and clearing the corresponding
> > + * fs_context field, which is done before calling fill
> > + * super via .get_tree()) there may be some strings to
> > + * cleanup.
> > + */
>
> The code looks straightforward but I find the comment confusing. How
> can
> the VFS pass ownership of the xfs_mount if it's an XFS private data
> structure?
>
> > + kfree(mp->m_logname);
> > + kfree(mp->m_rtname);
> > + kfree(mp);
> > + }
> > + kfree(ctx);
>
> Also, should we at least reassign associated fc pointers to NULL if
> we
> have multiple places to free things like ctx or mp?
Not sure about that, I think the next thing to happen
here is the mount context is freed by the VFS.
I'll check.
>
> Brian
>
> > +}
> > +
> > static const struct fs_context_operations xfs_context_ops = {
> > .parse_param = xfs_parse_param,
> > .get_tree = xfs_get_tree,
> > .reconfigure = xfs_reconfigure,
> > + .free = xfs_fc_free,
> > };
> >
> > static struct file_system_type xfs_fs_type = {
> >
