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>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 12b3bc026a68..d9d267181ddc 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2812,7 +2812,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
         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 @@ do_more:
                 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);