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Commit 8bdc81c5 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by Al Viro
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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: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 06688905

fs/jffs2/jffs2_fs_sb.h

+4 −0
Original line number Diff line number Diff line
@@ -126,6 +126,10 @@ struct jffs2_sb_info { 
	struct jffs2_inodirty *wbuf_inodes;

	struct rw_semaphore wbuf_sem;	/* Protects the write buffer */



	struct delayed_work wbuf_dwork; /* write-buffer write-out work */

	int wbuf_queued;                /* non-zero delayed work is queued */

	spinlock_t wbuf_dwork_lock;     /* protects wbuf_dwork and and wbuf_queued */



	unsigned char *oobbuf;

	int oobavail; /* How many bytes are available for JFFS2 in OOB */

#endif

fs/jffs2/os-linux.h

+2 −5
Original line number Diff line number Diff line
@@ -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);

fs/jffs2/super.c

+0 −13
Original line number Diff line number Diff line
@@ -63,18 +63,6 @@ static void jffs2_i_init_once(void *foo) 
	inode_init_once(&f->vfs_inode);

}



static void jffs2_write_super(struct super_block *sb)

{

	struct jffs2_sb_info *c = JFFS2_SB_INFO(sb);



	sb->s_dirt = 0;



	if (!(sb->s_flags & MS_RDONLY)) {

		jffs2_dbg(1, "%s()\n", __func__);

		jffs2_flush_wbuf_gc(c, 0);

	}

}



static const char *jffs2_compr_name(unsigned int compr)

{

	switch (compr) {
@@ -246,7 +234,6 @@ static const struct super_operations jffs2_super_operations = 
	.alloc_inode =	jffs2_alloc_inode,

	.destroy_inode =jffs2_destroy_inode,

	.put_super =	jffs2_put_super,

	.write_super =	jffs2_write_super,

	.statfs =	jffs2_statfs,

	.remount_fs =	jffs2_remount_fs,

	.evict_inode =	jffs2_evict_inode,

fs/jffs2/wbuf.c

+52 −3
Original line number Diff line number Diff line
@@ -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 @@ static void jffs2_wbuf_dirties_inode(struct jffs2_sb_info *c, uint32_t ino) 
{

	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 @@ int jffs2_write_nand_badblock(struct jffs2_sb_info *c, struct jffs2_eraseblock * 
	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 @@ int jffs2_nand_flash_setup(struct jffs2_sb_info *c) 


	/* 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 @@ int jffs2_dataflash_setup(struct jffs2_sb_info *c) { 


	/* 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 @@ int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c) { 


	/* 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 @@ int jffs2_ubivol_setup(struct jffs2_sb_info *c) { 
		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;