Enable multipage folio support for the afs filesystem.  This is on top of
Matthew Wilcox's for-next branch.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
---
 fs/afs/inode.c |    2 ++
 fs/afs/write.c |    2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 5964f8aee090..7dc7eb5f8e63 100644
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -96,12 +96,14 @@ static int afs_inode_init_from_status(struct afs_operation *op,
 		inode->i_op	= &afs_file_inode_operations;
 		inode->i_fop	= &afs_file_operations;
 		inode->i_mapping->a_ops	= &afs_file_aops;
+		mapping_set_large_folios(inode->i_mapping);
 		break;
 	case AFS_FTYPE_DIR:
 		inode->i_mode	= S_IFDIR |  (status->mode & S_IALLUGO);
 		inode->i_op	= &afs_dir_inode_operations;
 		inode->i_fop	= &afs_dir_file_operations;
 		inode->i_mapping->a_ops	= &afs_dir_aops;
+		mapping_set_large_folios(inode->i_mapping);
 		break;
 	case AFS_FTYPE_SYMLINK:
 		/* Symlinks with a mode of 0644 are actually mountpoints. */
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 5e9157d0da29..d6cc0fa44316 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -91,7 +91,7 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 			goto flush_conflicting_write;
 	}
 
-	*_page = &folio->page;
+	*_page = folio_file_page(folio, pos / PAGE_SIZE);
 	_leave(" = 0");
 	return 0;
 

Hi David,

I love your patch! Yet something to improve:

[auto build test ERROR on dhowells-fs/fscache-next]
[also build test ERROR on linux/master linus/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/David-Howells/afs-Enable-multipage-folio-support/20220226-075436
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git fscache-next
config: i386-randconfig-a005 (https://download.01.org/0day-ci/archive/20220226/202202261524.4tAqmT0a-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/91637acf6da0c809e1bedc59696d6bc0a8604f03
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review David-Howells/afs-Enable-multipage-folio-support/20220226-075436
        git checkout 91637acf6da0c809e1bedc59696d6bc0a8604f03
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "PageHeadHuge" [fs/afs/kafs.ko] undefined!

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

On Fri, Feb 25, 2022 at 11:53:46PM +0000, David Howells wrote:
> Enable multipage folio support for the afs filesystem.  This is on top of
> Matthew Wilcox's for-next branch.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: Marc Dionne <marc.dionne@auristor.com>
> cc: linux-afs@lists.infradead.org

I can't say that I've audited AFS for its correct use of folios
everywhere, but since you've tested it, I have no objections:

Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>