ext4: Clean up s_dirt handling
We don't need to set s_dirt in most of the ext4 code when journaling
is enabled. In ext3/4 some of the summary statistics for # of free
inodes, blocks, and directories are calculated from the per-block
group statistics when the file system is mounted or unmounted. As a
result the superblock doesn't have to be updated, either via the
journal or by setting s_dirt. There are a few exceptions, most
notably when resizing the file system, where the superblock needs to
be modified --- and in that case it should be done as a journalled
operation if possible, and s_dirt set only in no-journal mode.
This patch will optimize out some unneeded disk writes when using ext4
with a journal.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 12b3bc0..d9d2671 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2812,7 +2812,7 @@
err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
out_err:
- sb->s_dirt = 1;
+ ext4_mark_super_dirty(sb);
brelse(bitmap_bh);
return err;
}
@@ -4680,7 +4680,7 @@
put_bh(bitmap_bh);
goto do_more;
}
- sb->s_dirt = 1;
+ ext4_mark_super_dirty(sb);
error_return:
if (freed)
dquot_free_block(inode, freed);