Re: [PATCH] netfs, ceph: Partially revert "netfs: Replace PG_fscache by setting folio->private and marking dirty"

[Xiubo Li <xiubli@redhat.com>]

On 8/15/24 03:50, David Howells wrote:
>      
> This partially reverts commit 2ff1e97587f4d398686f52c07afde3faf3da4e5c.
>
> In addition to reverting the removal of PG_private_2 wrangling from the
> buffered read code[1][2], the removal of the waits for PG_private_2 from
> netfs_release_folio() and netfs_invalidate_folio() need reverting too.
>
> It also adds a wait into ceph_evict_inode() to wait for netfs read and
> copy-to-cache ops to complete.
>
> Fixes: 2ff1e97587f4 ("netfs: Replace PG_fscache by setting folio->private and marking dirty")
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Max Kellermann <max.kellermann@ionos.com>
> cc: Ilya Dryomov <idryomov@gmail.com>
> cc: Xiubo Li <xiubli@redhat.com>
> cc: Jeff Layton <jlayton@kernel.org>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: ceph-devel@vger.kernel.org
> cc: netfs@lists.linux.dev
> cc: linux-fsdevel@vger.kernel.org
> cc: linux-mm@kvack.org
> Link: https://lore.kernel.org/r/3575457.1722355300@warthog.procyon.org.uk [1]
> Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8e5ced7804cb9184c4a23f8054551240562a8eda [2]
> ---
>   fs/ceph/inode.c |    1 +
>   fs/netfs/misc.c |    7 +++++++
>   2 files changed, 8 insertions(+)
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 71cd70514efa..4a8eec46254b 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -695,6 +695,7 @@ void ceph_evict_inode(struct inode *inode)
>   
>   	percpu_counter_dec(&mdsc->metric.total_inodes);
>   
> +	netfs_wait_for_outstanding_io(inode);
>   	truncate_inode_pages_final(&inode->i_data);
>   	if (inode->i_state & I_PINNING_NETFS_WB)
>   		ceph_fscache_unuse_cookie(inode, true);
> diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c
> index 83e644bd518f..554a1a4615ad 100644
> --- a/fs/netfs/misc.c
> +++ b/fs/netfs/misc.c
> @@ -101,6 +101,8 @@ void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
>   
>   	_enter("{%lx},%zx,%zx", folio->index, offset, length);
>   
> +	folio_wait_private_2(folio); /* [DEPRECATED] */
> +
>   	if (!folio_test_private(folio))
>   		return;
>   
> @@ -165,6 +167,11 @@ bool netfs_release_folio(struct folio *folio, gfp_t gfp)
>   
>   	if (folio_test_private(folio))
>   		return false;
> +	if (unlikely(folio_test_private_2(folio))) { /* [DEPRECATED] */
> +		if (current_is_kswapd() || !(gfp & __GFP_FS))
> +			return false;
> +		folio_wait_private_2(folio);
> +	}
>   	fscache_note_page_release(netfs_i_cookie(ctx));
>   	return true;
>   }
>
Tested it and worked fine.

Reviewed-by: Xiubo Li <xiubli@redhat.com>
Tested-by: Xiubo Li <xiubli@redhat.com>

Thanks