ext4: split off ext4_journalled_invalidatepage()

In data=journal mode we don't need delalloc or DIO handling in invalidatepage
and similarly in other modes we don't need the journal handling. So split
invalidatepage implementations.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/inode.c

@@ -2880,25 +2880,34 @@ static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offs
 
 static void ext4_invalidatepage(struct page *page, unsigned long offset)
 {
-	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
-
 	trace_ext4_invalidatepage(page, offset);
 
 	/*
 	 * free any io_end structure allocated for buffers to be discarded
 	 */
 	if (ext4_should_dioread_nolock(page->mapping->host))
 		ext4_invalidatepage_free_endio(page, offset);
+
+	/* No journalling happens on data buffers when this function is used */
+	WARN_ON(page_has_buffers(page) && buffer_jbd(page_buffers(page)));
+
+	block_invalidatepage(page, offset);
+}
+
+static void ext4_journalled_invalidatepage(struct page *page,
+					   unsigned long offset)
+{
+	journal_t *journal = EXT4_JOURNAL(page->mapping->host);
+
+	trace_ext4_journalled_invalidatepage(page, offset);
+
 	/*
 	 * If it's a full truncate we just forget about the pending dirtying
 	 */
 	if (offset == 0)
 		ClearPageChecked(page);
 
-	if (journal)
-		jbd2_journal_invalidatepage(journal, page, offset);
-	else
-		block_invalidatepage(page, offset);
+	jbd2_journal_invalidatepage(journal, page, offset);
 }
 
 static int ext4_releasepage(struct page *page, gfp_t wait)
@@ -3264,7 +3273,7 @@ static const struct address_space_operations ext4_journalled_aops = {
 	.write_end		= ext4_journalled_write_end,
 	.set_page_dirty		= ext4_journalled_set_page_dirty,
 	.bmap			= ext4_bmap,
-	.invalidatepage		= ext4_invalidatepage,
+	.invalidatepage		= ext4_journalled_invalidatepage,
 	.releasepage		= ext4_releasepage,
 	.direct_IO		= ext4_direct_IO,
 	.is_partially_uptodate  = block_is_partially_uptodate,

include/trace/events/ext4.h

@@ -451,7 +451,7 @@ DEFINE_EVENT(ext4__page_op, ext4_releasepage,
 	TP_ARGS(page)
 );
 
-TRACE_EVENT(ext4_invalidatepage,
+DECLARE_EVENT_CLASS(ext4_invalidatepage_op,
 	TP_PROTO(struct page *page, unsigned long offset),
 
 	TP_ARGS(page, offset),
@@ -477,6 +477,18 @@ TRACE_EVENT(ext4_invalidatepage,
 		  (unsigned long) __entry->index, __entry->offset)
 );
 
+DEFINE_EVENT(ext4_invalidatepage_op, ext4_invalidatepage,
+	TP_PROTO(struct page *page, unsigned long offset),
+
+	TP_ARGS(page, offset)
+);
+
+DEFINE_EVENT(ext4_invalidatepage_op, ext4_journalled_invalidatepage,
+	TP_PROTO(struct page *page, unsigned long offset),
+
+	TP_ARGS(page, offset)
+);
+
 TRACE_EVENT(ext4_discard_blocks,
 	TP_PROTO(struct super_block *sb, unsigned long long blk,
 			unsigned long long count),