Re: [PATCH v5 03/16] fs: introduce alloc_inode_sb() to allocate filesystems specific inode

[Muchun Song <songmuchun@bytedance.com>]

On Wed, Jan 12, 2022 at 2:55 AM Roman Gushchin <guro@fb.com> wrote:
>
> On Mon, Dec 20, 2021 at 04:56:36PM +0800, Muchun Song wrote:
> > The allocated inode cache is supposed to be added to its memcg list_lru
> > which should be allocated as well in advance. That can be done by
> > kmem_cache_alloc_lru() which allocates object and list_lru. The file
> > systems is main user of it. So introduce alloc_inode_sb() to allocate
> > file system specific inodes and set up the inode reclaim context
> > properly. The file system is supposed to use alloc_inode_sb() to
> > allocate inodes. In the later patches, we will convert all users to the
> > new API.
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> > ---
> >  Documentation/filesystems/porting.rst |  5 +++++
> >  fs/inode.c                            |  2 +-
> >  include/linux/fs.h                    | 11 +++++++++++
> >  3 files changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
> > index bf19fd6b86e7..c9c157d7b7bb 100644
> > --- a/Documentation/filesystems/porting.rst
> > +++ b/Documentation/filesystems/porting.rst
> > @@ -45,6 +45,11 @@ typically between calling iget_locked() and unlocking the inode.
> >
> >  At some point that will become mandatory.
> >
> > +**mandatory**
> > +
> > +The foo_inode_info should always be allocated through alloc_inode_sb() rather
> > +than kmem_cache_alloc() or kmalloc() related.
>
> I'd add a couple of words on why it has to be allocated this way.

Will do.

> > +
> >  ---
>
> Reviewed-by: Roman Gushchin <guro@fb.com>

Thanks.