affs: get rid of affs_sync_super
This patch makes affs 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.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/affs/super.c b/fs/affs/super.c
index 0496cbb..c70f1e5 100644
--- a/fs/affs/super.c
+++ b/fs/affs/super.c
@@ -17,6 +17,7 @@
#include <linux/magic.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/writeback.h>
#include "affs.h"
extern struct timezone sys_tz;
@@ -47,6 +48,7 @@
struct affs_sb_info *sbi = AFFS_SB(sb);
pr_debug("AFFS: put_super()\n");
+ cancel_delayed_work_sync(&sbi->sb_work);
kfree(sbi->s_prefix);
affs_free_bitmap(sb);
affs_brelse(sbi->s_root_bh);
@@ -54,23 +56,45 @@
sb->s_fs_info = NULL;
}
-static void
-affs_write_super(struct super_block *sb)
-{
- if (!(sb->s_flags & MS_RDONLY))
- affs_commit_super(sb, 1);
- sb->s_dirt = 0;
- pr_debug("AFFS: write_super() at %lu, clean=2\n", get_seconds());
-}
-
static int
affs_sync_fs(struct super_block *sb, int wait)
{
affs_commit_super(sb, wait);
- sb->s_dirt = 0;
return 0;
}
+static void flush_superblock(struct work_struct *work)
+{
+ struct affs_sb_info *sbi;
+ struct super_block *sb;
+
+ sbi = container_of(work, struct affs_sb_info, sb_work.work);
+ sb = sbi->sb;
+
+ spin_lock(&sbi->work_lock);
+ sbi->work_queued = 0;
+ spin_unlock(&sbi->work_lock);
+
+ affs_commit_super(sb, 1);
+}
+
+void affs_mark_sb_dirty(struct super_block *sb)
+{
+ struct affs_sb_info *sbi = AFFS_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->sb_work, delay);
+ sbi->work_queued = 1;
+ }
+ spin_unlock(&sbi->work_lock);
+}
+
static struct kmem_cache * affs_inode_cachep;
static struct inode *affs_alloc_inode(struct super_block *sb)
@@ -132,7 +156,6 @@
.write_inode = affs_write_inode,
.evict_inode = affs_evict_inode,
.put_super = affs_put_super,
- .write_super = affs_write_super,
.sync_fs = affs_sync_fs,
.statfs = affs_statfs,
.remount_fs = affs_remount,
@@ -302,6 +325,8 @@
sbi->sb = sb;
mutex_init(&sbi->s_bmlock);
spin_lock_init(&sbi->symlink_lock);
+ spin_lock_init(&sbi->work_lock);
+ INIT_DELAYED_WORK(&sbi->sb_work, flush_superblock);
if (!parse_options(data,&uid,&gid,&i,&reserved,&root_block,
&blocksize,&sbi->s_prefix,
@@ -526,6 +551,7 @@
return -EINVAL;
}
+ flush_delayed_work_sync(&sbi->sb_work);
replace_mount_options(sb, new_opts);
sbi->s_flags = mount_flags;