ocfs2: simplify ocfs2_invalidatepage() and ocfs2_releasepage()

Ocfs2 doesn't do data journalling.  Thus its ->invalidatepage and
->releasepage functions never get called on buffers that have journal
heads attached.  So just use standard variants of functions from
buffer.c.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/aops.c

@@ -594,26 +594,11 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
 	ocfs2_rw_unlock(inode, level);
 }
 
-/*
- * ocfs2_invalidatepage() and ocfs2_releasepage() are shamelessly stolen
- * from ext3.  PageChecked() bits have been removed as OCFS2 does not
- * do journalled data.
- */
-static void ocfs2_invalidatepage(struct page *page, unsigned int offset,
-				 unsigned int length)
-{
-	journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
-
-	jbd2_journal_invalidatepage(journal, page, offset, length);
-}
-
 static int ocfs2_releasepage(struct page *page, gfp_t wait)
 {
-	journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
-
 	if (!page_has_buffers(page))
 		return 0;
-	return jbd2_journal_try_to_free_buffers(journal, page, wait);
+	return try_to_free_buffers(page);
 }
 
 static ssize_t ocfs2_direct_IO(int rw,
@@ -2092,7 +2077,7 @@ const struct address_space_operations ocfs2_aops = {
 	.write_end		= ocfs2_write_end,
 	.bmap			= ocfs2_bmap,
 	.direct_IO		= ocfs2_direct_IO,
-	.invalidatepage		= ocfs2_invalidatepage,
+	.invalidatepage		= block_invalidatepage,
 	.releasepage		= ocfs2_releasepage,
 	.migratepage		= buffer_migrate_page,
 	.is_partially_uptodate	= block_is_partially_uptodate,