Re: [PATCH 26/32] afs: Use fs_context to pass parameters over automount [ver #8]

From: David Howells
Date: Thu Jun 07 2018 - 16:45:37 EST


Goldwyn Rodrigues <rgoldwyn@xxxxxxx> wrote:

Goldwyn Rodrigues <rgoldwyn@xxxxxxx> wrote:

> > +static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
> > +{
> > + struct fs_context *fc;
> > + struct vfsmount *mnt;
> > + int ret;
> > +
> > + BUG_ON(!d_inode(mntpt));
> > +
> > + fc = vfs_new_fs_context(&afs_fs_type, mntpt, 0,
> > + FS_CONTEXT_FOR_SUBMOUNT);
> > + if (IS_ERR(fc))
> > + return ERR_CAST(fc);
> > +
> > + ret = afs_mntpt_set_params(fc, mntpt);
> > + if (ret < 0)
> > + goto error_fc;
> > +
> > + ret = vfs_get_tree(fc);
> > + if (ret < 0)
> > + goto error_fc;
> > +
> > + mnt = vfs_create_mount(fc, 0);
> > + if (IS_ERR(mnt)) {
> > + ret = PTR_ERR(mnt);
> > + goto error_fc;
> > + }
> >
> > - free_page((unsigned long) devname);
> > - free_page((unsigned long) options);
> > - _leave(" = %p", mnt);
> > + put_fs_context(fc);
> > return mnt;
> >
> Why are you performing a put_fs_context(fc) in the success code path? Do
> we not need a reference of fc anymore?

No. This is the ->d_automount() hook. The context is created at the top of
the function, configuration is done, the superblock is obtained, a mount
object is created (for which we get a ref returned). After that point, we
don't need the context any more and no one else is going to clean it up for
us.

David