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>
diff --git a/fs/jffs2/wbuf.c b/fs/jffs2/wbuf.c
index 74d9be1..6f4529d 100644
--- a/fs/jffs2/wbuf.c
+++ b/fs/jffs2/wbuf.c
@@ -20,6 +20,7 @@
#include <linux/mtd/nand.h>
#include <linux/jiffies.h>
#include <linux/sched.h>
+#include <linux/writeback.h>
#include "nodelist.h"
@@ -85,7 +86,7 @@
{
struct jffs2_inodirty *new;
- /* Mark the superblock dirty so that kupdated will flush... */
+ /* Schedule delayed write-buffer write-out */
jffs2_dirty_trigger(c);
if (jffs2_wbuf_pending_for_ino(c, ino))
@@ -1148,6 +1149,47 @@
return 1;
}
+static struct jffs2_sb_info *work_to_sb(struct work_struct *work)
+{
+ struct delayed_work *dwork;
+
+ dwork = container_of(work, struct delayed_work, work);
+ return container_of(dwork, struct jffs2_sb_info, wbuf_dwork);
+}
+
+static void delayed_wbuf_sync(struct work_struct *work)
+{
+ struct jffs2_sb_info *c = work_to_sb(work);
+ struct super_block *sb = OFNI_BS_2SFFJ(c);
+
+ spin_lock(&c->wbuf_dwork_lock);
+ c->wbuf_queued = 0;
+ spin_unlock(&c->wbuf_dwork_lock);
+
+ if (!(sb->s_flags & MS_RDONLY)) {
+ jffs2_dbg(1, "%s()\n", __func__);
+ jffs2_flush_wbuf_gc(c, 0);
+ }
+}
+
+void jffs2_dirty_trigger(struct jffs2_sb_info *c)
+{
+ struct super_block *sb = OFNI_BS_2SFFJ(c);
+ unsigned long delay;
+
+ if (sb->s_flags & MS_RDONLY)
+ return;
+
+ spin_lock(&c->wbuf_dwork_lock);
+ if (!c->wbuf_queued) {
+ jffs2_dbg(1, "%s()\n", __func__);
+ delay = msecs_to_jiffies(dirty_writeback_interval * 10);
+ queue_delayed_work(system_long_wq, &c->wbuf_dwork, delay);
+ c->wbuf_queued = 1;
+ }
+ spin_unlock(&c->wbuf_dwork_lock);
+}
+
int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
{
struct nand_ecclayout *oinfo = c->mtd->ecclayout;
@@ -1169,6 +1211,8 @@
/* Initialise write buffer */
init_rwsem(&c->wbuf_sem);
+ spin_lock_init(&c->wbuf_dwork_lock);
+ INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
c->wbuf_pagesize = c->mtd->writesize;
c->wbuf_ofs = 0xFFFFFFFF;
@@ -1207,8 +1251,8 @@
/* Initialize write buffer */
init_rwsem(&c->wbuf_sem);
-
-
+ spin_lock_init(&c->wbuf_dwork_lock);
+ INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
c->wbuf_pagesize = c->mtd->erasesize;
/* Find a suitable c->sector_size
@@ -1267,6 +1311,9 @@
/* Initialize write buffer */
init_rwsem(&c->wbuf_sem);
+ spin_lock_init(&c->wbuf_dwork_lock);
+ INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
+
c->wbuf_pagesize = c->mtd->writesize;
c->wbuf_ofs = 0xFFFFFFFF;
@@ -1299,6 +1346,8 @@
return 0;
init_rwsem(&c->wbuf_sem);
+ spin_lock_init(&c->wbuf_dwork_lock);
+ INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
c->wbuf_pagesize = c->mtd->writesize;
c->wbuf_ofs = 0xFFFFFFFF;