hfs: get rid of hfs_sync_super

This patch makes hfs stop using the VFS '->write_super()' method along with
the 's_dirt' superblock flag, because they are on their way out.

The whole "superblock write-out" VFS infrastructure is served by the
'sync_supers()' kernel thread, which wakes up every 5 (by default) seconds and
writes out all dirty superblocks using the '->write_super()' call-back.  But the
problem with this thread is that it wastes power by waking up the system every
5 seconds, even if there are no diry superblocks, or there are no client
file-systems which would need this (e.g., btrfs does not use
'->write_super()'). So we want to kill it completely and thus, we need to make
file-systems to stop using the '->write_super()' VFS service, and then remove
it together with the kernel thread.

Tested using fsstress from the LTP project.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 4 insertions, 7 deletions

diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 90c1ccbff8e4..ee1bc55677f1 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -220,7 +220,7 @@ struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, umode_t mode)
         insert_inode_hash(inode);
         mark_inode_dirty(inode);
         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
-        sb->s_dirt = 1;
+        hfs_mark_mdb_dirty(sb);
 
         return inode;
 }
@@ -235,7 +235,7 @@ void hfs_delete_inode(struct inode *inode)
                 if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
                         HFS_SB(sb)->root_dirs--;
                 set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
-                sb->s_dirt = 1;
+                hfs_mark_mdb_dirty(sb);
                 return;
         }
         HFS_SB(sb)->file_count--;
@@ -248,7 +248,7 @@ void hfs_delete_inode(struct inode *inode)
                 }
         }
         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
-        sb->s_dirt = 1;
+        hfs_mark_mdb_dirty(sb);
 }
 
 void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
@@ -644,10 +644,7 @@ static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
 
         /* sync the superblock to buffers */
         sb = inode->i_sb;
-        if (sb->s_dirt) {
-                sb->s_dirt = 0;
-                hfs_mdb_commit(sb);
-        }
+        flush_delayed_work_sync(&HFS_SB(sb)->mdb_work);
         /* .. finally sync the buffers to disk */
         err = sync_blockdev(sb->s_bdev);
         if (!ret)