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, 1 insertions, 5 deletions

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 95b7594..bd30799 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -377,14 +377,11 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
 	ext4_grpblk_t bit;
 	unsigned int i;
 	struct ext4_group_desc *desc;
-	struct ext4_super_block *es;
-	struct ext4_sb_info *sbi;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	int err = 0, ret, blk_free_count;
 	ext4_grpblk_t blocks_freed;
 	struct ext4_group_info *grp;
 
-	sbi = EXT4_SB(sb);
-	es = sbi->s_es;
 	ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
 
 	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
@@ -477,7 +474,6 @@ void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
 	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
 	if (!err)
 		err = ret;
-	sb->s_dirt = 1;
 
 error_return:
 	brelse(bitmap_bh);