fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info

Now that we got rid of the bdi abuse on character devices we can always use
sb->s_bdi to get at the backing_dev_info for a file, except for the block
device special case.  Export inode_to_bdi and replace uses of
mapping->backing_dev_info with it to prepare for the removal of
mapping->backing_dev_info.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

2 files changed, 4 insertions, 4 deletions

diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
index 7afb52f6a25a..51aa889611cf 100644
--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -1081,7 +1081,7 @@ mds_commit:
         spin_unlock(cinfo->lock);
         if (!cinfo->dreq) {
                 inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
-                inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
+                inc_bdi_stat(inode_to_bdi(page_file_mapping(req->wb_page)->host),
                              BDI_RECLAIMABLE);
                 __mark_inode_dirty(req->wb_context->dentry->d_inode,
                                    I_DIRTY_DATASYNC);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index af3af685a9e3..298abcc5281b 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -786,7 +786,7 @@ nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
         spin_unlock(cinfo->lock);
         if (!cinfo->dreq) {
                 inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
-                inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
+                inc_bdi_stat(inode_to_bdi(page_file_mapping(req->wb_page)->host),
                              BDI_RECLAIMABLE);
                 __mark_inode_dirty(req->wb_context->dentry->d_inode,
                                    I_DIRTY_DATASYNC);
@@ -853,7 +853,7 @@ static void
 nfs_clear_page_commit(struct page *page)
 {
         dec_zone_page_state(page, NR_UNSTABLE_NFS);
-        dec_bdi_stat(page_file_mapping(page)->backing_dev_info, BDI_RECLAIMABLE);
+        dec_bdi_stat(inode_to_bdi(page_file_mapping(page)->host), BDI_RECLAIMABLE);
 }
 
 /* Called holding inode (/cinfo) lock */
@@ -1564,7 +1564,7 @@ void nfs_retry_commit(struct list_head *page_list,
                 nfs_mark_request_commit(req, lseg, cinfo);
                 if (!cinfo->dreq) {
                         dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
-                        dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
+                        dec_bdi_stat(inode_to_bdi(page_file_mapping(req->wb_page)->host),
                                      BDI_RECLAIMABLE);
                 }
                 nfs_unlock_and_release_request(req);