gfs2: support ludicrously large folios in gfs2_trans_add_databufs()

We may someday support folios larger than 4GB, so use a size_t for the
byte count within a folio to prevent unpleasant truncations.

Link: https://lkml.kernel.org/r/20230612210141.730128-6-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/gfs2/aops.c

@@ -38,13 +38,13 @@
 
 
 void gfs2_trans_add_databufs(struct gfs2_inode *ip, struct folio *folio,
-			     unsigned int from, unsigned int len)
+			     size_t from, size_t len)
 {
 	struct buffer_head *head = folio_buffers(folio);
 	unsigned int bsize = head->b_size;
 	struct buffer_head *bh;
-	unsigned int to = from + len;
-	unsigned int start, end;
+	size_t to = from + len;
+	size_t start, end;
 
 	for (bh = head, start = 0; bh != head || !start;
 	     bh = bh->b_this_page, start = end) {

fs/gfs2/aops.h

@@ -10,6 +10,6 @@
 
 extern void adjust_fs_space(struct inode *inode);
 extern void gfs2_trans_add_databufs(struct gfs2_inode *ip, struct folio *folio,
-				    unsigned int from, unsigned int len);
+				    size_t from, size_t len);
 
 #endif /* __AOPS_DOT_H__ */