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/ialloc.c b/fs/ext4/ialloc.c
index 25c4b3173fd9..ac377505ed57 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -279,7 +279,7 @@ out:
                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
                 if (!fatal)
                         fatal = err;
-                sb->s_dirt = 1;
+                ext4_mark_super_dirty(sb);
         } else
                 ext4_error(sb, "bit already cleared for inode %lu", ino);
 
@@ -965,7 +965,7 @@ got:
         percpu_counter_dec(&sbi->s_freeinodes_counter);
         if (S_ISDIR(mode))
                 percpu_counter_inc(&sbi->s_dirs_counter);
-        sb->s_dirt = 1;
+        ext4_mark_super_dirty(sb);
 
         if (sbi->s_log_groups_per_flex) {
                 flex_group = ext4_flex_group(sbi, group);