ext4: dynamically allocate the jbd2_inode in ext4_inode_info as necessary
Replace the jbd2_inode structure (which is 48 bytes) with a pointer
and only allocate the jbd2_inode when it is needed --- that is, when
the file system has a journal present and the inode has been opened
for writing. This allows us to further slim down the ext4_inode_info
structure.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0801ee6..2693fcd 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -55,10 +55,17 @@
loff_t new_size)
{
trace_ext4_begin_ordered_truncate(inode, new_size);
- return jbd2_journal_begin_ordered_truncate(
- EXT4_SB(inode->i_sb)->s_journal,
- &EXT4_I(inode)->jinode,
- new_size);
+ /*
+ * If jinode is zero, then we never opened the file for
+ * writing, so there's no need to call
+ * jbd2_journal_begin_ordered_truncate() since there's no
+ * outstanding writes we need to flush.
+ */
+ if (!EXT4_I(inode)->jinode)
+ return 0;
+ return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode),
+ EXT4_I(inode)->jinode,
+ new_size);
}
static void ext4_invalidatepage(struct page *page, unsigned long offset);
@@ -4054,7 +4061,7 @@
if (ext4_should_journal_data(inode)) {
err = ext4_handle_dirty_metadata(handle, inode, bh);
} else {
- if (ext4_should_order_data(inode))
+ if (ext4_should_order_data(inode) && EXT4_I(inode)->jinode)
err = ext4_jbd2_file_inode(handle, inode);
mark_buffer_dirty(bh);
}