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>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/affs/affs.h b/fs/affs/affs.h
index 5a726e992245..3a130e27eb15 100644
--- a/fs/affs/affs.h
+++ b/fs/affs/affs.h
@@ -3,6 +3,7 @@
 #include <linux/buffer_head.h>
 #include <linux/amigaffs.h>
 #include <linux/mutex.h>
+#include <linux/workqueue.h>
 
 /* AmigaOS allows file names with up to 30 characters length.
  * Names longer than that will be silently truncated. If you
@@ -101,6 +102,9 @@ struct affs_sb_info {
         char s_volume[32];              /* Volume prefix for absolute symlinks. */
         spinlock_t symlink_lock;        /* protects the previous two */
         struct super_block *sb;         /* the VFS superblock object */
+        int work_queued;                /* non-zero delayed work is queued */
+        struct delayed_work sb_work;    /* superblock flush delayed work */
+        spinlock_t work_lock;           /* protects sb_work and work_queued */
 };
 
 #define SF_INTL         0x0001          /* International filesystem. */
@@ -121,6 +125,8 @@ static inline struct affs_sb_info *AFFS_SB(struct super_block *sb)
         return sb->s_fs_info;
 }
 
+void affs_mark_sb_dirty(struct super_block *sb);
+
 /* amigaffs.c */
 
 extern int      affs_insert_hash(struct inode *inode, struct buffer_head *bh);