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>
diff --git a/fs/hfs/super.c b/fs/hfs/super.c
index 99c6239..4eb873e 100644
--- a/fs/hfs/super.c
+++ b/fs/hfs/super.c
@@ -29,38 +29,9 @@
MODULE_LICENSE("GPL");
-/*
- * hfs_write_super()
- *
- * Description:
- * This function is called by the VFS only. When the filesystem
- * is mounted r/w it updates the MDB on disk.
- * Input Variable(s):
- * struct super_block *sb: Pointer to the hfs superblock
- * Output Variable(s):
- * NONE
- * Returns:
- * void
- * Preconditions:
- * 'sb' points to a "valid" (struct super_block).
- * Postconditions:
- * The MDB is marked 'unsuccessfully unmounted' by clearing bit 8 of drAtrb
- * (hfs_put_super() must set this flag!). Some MDB fields are updated
- * and the MDB buffer is written to disk by calling hfs_mdb_commit().
- */
-static void hfs_write_super(struct super_block *sb)
-{
- sb->s_dirt = 0;
-
- /* sync everything to the buffers */
- hfs_mdb_commit(sb);
-}
-
static int hfs_sync_fs(struct super_block *sb, int wait)
{
hfs_mdb_commit(sb);
- sb->s_dirt = 0;
-
return 0;
}
@@ -73,11 +44,44 @@
*/
static void hfs_put_super(struct super_block *sb)
{
+ cancel_delayed_work_sync(&HFS_SB(sb)->mdb_work);
hfs_mdb_close(sb);
/* release the MDB's resources */
hfs_mdb_put(sb);
}
+static void flush_mdb(struct work_struct *work)
+{
+ struct hfs_sb_info *sbi;
+ struct super_block *sb;
+
+ sbi = container_of(work, struct hfs_sb_info, mdb_work.work);
+ sb = sbi->sb;
+
+ spin_lock(&sbi->work_lock);
+ sbi->work_queued = 0;
+ spin_unlock(&sbi->work_lock);
+
+ hfs_mdb_commit(sb);
+}
+
+void hfs_mark_mdb_dirty(struct super_block *sb)
+{
+ struct hfs_sb_info *sbi = HFS_SB(sb);
+ unsigned long delay;
+
+ if (sb->s_flags & MS_RDONLY)
+ return;
+
+ spin_lock(&sbi->work_lock);
+ if (!sbi->work_queued) {
+ delay = msecs_to_jiffies(dirty_writeback_interval * 10);
+ queue_delayed_work(system_long_wq, &sbi->mdb_work, delay);
+ sbi->work_queued = 1;
+ }
+ spin_unlock(&sbi->work_lock);
+}
+
/*
* hfs_statfs()
*
@@ -177,7 +181,6 @@
.write_inode = hfs_write_inode,
.evict_inode = hfs_evict_inode,
.put_super = hfs_put_super,
- .write_super = hfs_write_super,
.sync_fs = hfs_sync_fs,
.statfs = hfs_statfs,
.remount_fs = hfs_remount,
@@ -382,6 +385,8 @@
sbi->sb = sb;
sb->s_fs_info = sbi;
+ spin_lock_init(&sbi->work_lock);
+ INIT_DELAYED_WORK(&sbi->mdb_work, flush_mdb);
res = -EINVAL;
if (!parse_options((char *)data, sbi)) {