jffs2: get rid of jffs2_sync_super

Currently JFFS2 file-system maps the VFS "superblock" abstraction to the
write-buffer. Namely, it uses VFS services to synchronize the write-buffer
periodically.

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 superblock 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 no matter what. 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.

This patch switches the JFFS2 write-buffer management from
'->write_super()'/'->s_dirt' to a delayed work. Instead of setting the 's_dirt'
flag we just schedule a delayed work for synchronizing the write-buffer.

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

1 files changed, 2 insertions, 5 deletions

diff --git a/fs/jffs2/os-linux.h b/fs/jffs2/os-linux.h
index 1cd3aec9d9ae..bcd983d7e7f9 100644
--- a/fs/jffs2/os-linux.h
+++ b/fs/jffs2/os-linux.h
@@ -95,6 +95,7 @@ static inline void jffs2_init_inode_info(struct jffs2_inode_info *f)
 #define jffs2_ubivol(c) (0)
 #define jffs2_ubivol_setup(c) (0)
 #define jffs2_ubivol_cleanup(c) do {} while (0)
+#define jffs2_dirty_trigger(c) do {} while (0)
 
 #else /* NAND and/or ECC'd NOR support present */
 
@@ -135,14 +136,10 @@ void jffs2_ubivol_cleanup(struct jffs2_sb_info *c);
 #define jffs2_nor_wbuf_flash(c) (c->mtd->type == MTD_NORFLASH && ! (c->mtd->flags & MTD_BIT_WRITEABLE))
 int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c);
 void jffs2_nor_wbuf_flash_cleanup(struct jffs2_sb_info *c);
+void jffs2_dirty_trigger(struct jffs2_sb_info *c);
 
 #endif /* WRITEBUFFER */
 
-static inline void jffs2_dirty_trigger(struct jffs2_sb_info *c)
-{
-        OFNI_BS_2SFFJ(c)->s_dirt = 1;
-}
-
 /* background.c */
 int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c);
 void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c);